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Climate , D. G. Feist 8 ˚ 4 a University of Sciences Sciences Dynamics Chemistry of the Past Solid Earth O Techniques Geoscientific Methods and and Physics Atmospheric Atmospheric Atmospheric Data Systems Geoscientific 2 ` a degli Studi, L’Aquila, , P. Raspollini Earth System Earth System Measurement Instrumentation Hydrology and , M. Weber Ocean Science Annales Annales Biogeosciences 1 The Cryosphere Natural Hazards Hazards Natural , M. Milz and Earth System System Earth and 10,**** 1,** Model Development Geophysicae ¨ ur Physik der Atmosph , C. Cornacchia , G. Stiller 3,* † 11, , C. Piccolo , A. Lengel 4 1

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, A. Bracher 2 , C. Schiller 11 Climate , A. Kleinert 7 Sciences Sciences Dynamics Chemistry of the Past Solid Earth , G. Pappalardo Techniques Geoscientific Methods and and Physics Advances in Advances 2 Atmospheric Atmospheric Atmospheric Data Systems Geoscientific Geosciences Earth System Earth System Measurement Instrumentation Hydrology and Ocean Science Biogeosciences The Cryosphere Natural Hazards Hazards Natural , G. Berthet , S. Rohs 1 7 EGU Journal Logos (RGB) EGU Journal and Earth System System Earth and , M. Iarlori ¨ ur Luft- und Raumfahrt (DLR), Institut f Model Development 6 ce, Exeter, UK , J. Ovarlez ffi , V. Rizi 2 9,*** , A. Fix , H. Oelhaf 1 1 1 enhofen, Germany ¨ ¨ uller ff ulich, Germany ´ eans, France now at: Met O now at: METEOTEST, Bern, Switzerland Istituto di Fisica Applicata “Nello Carrara” (IFAC), del Consiglio NazionaleInstitute delle for Ricerche Energy and Climate Research – Stratosphere (IEK-7), Forschungszentrum ¨ now at: Carl Zeiss AG, Oberkochen, Germany This discussion paper is/has beenand under Physics review (ACP). for Please the refer journal to Atmospheric the Chemistry corresponding final paper in ACP if available. ulich, J Institute of Environmental Physics and Remote Sensing (IUP/IFE), University ofCNR-IMAA, Bremen, Consiglio Nazionale delle Ricerche – Istituto di MetodologieMax per Planck l’Analisi Institute for Biogeochemistry, Jena,Deutsches Germany Zentrum f Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute ofLaboratoire de Technology Physique et Chimie de l’Environnement et de l’Espace (LPC2E), CNRS, Department of Computer science, Electrical and Space engineering, Lule Institute of Applied Physics (IAP), University of Bern, Bern, Switzerland CETEMPS – Dipartimento di Scienze Fisiche e Chimiche – Universit deceased now at: Alfred Wegener Institute (AWI), Bremerhaven, Germany S. C. M J.-B. Renard Oberpfa 3 Bremen, Germany 4 Ambientale, Tito Scalo,5 Potenza, Italy 6 * ** *** **** † Received: 11 January 2013 – Accepted: 1Correspondence February to: 2013 G. – Wetzel Published: ([email protected]) 15 FebruaryPublished 2013 by Copernicus Publications on behalf of the European Geosciences Union. H. Fischer G. Zhang 1 (KIT), Karlsruhe, Germany 2 Orl Italy 8 Technology, Kiruna, Sweden 9 10 (CNR), Firenze, Italy 11 J 7 operational data collected between July 2002 and March 2004 G. Wetzel Validation of MIPAS-ENVISAT H Atmos. Chem. Phys. Discuss., 13, 4433–4489,www.atmos-chem-phys-discuss.net/13/4433/2013/ 2013 doi:10.5194/acpd-13-4433-2013 © Author(s) 2013. CC Attribution 3.0 License. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | O O 2 2 ects, sharp O values in ff erent biases 2 ff O data is obvi- 2 O profiles are less reliable, suf- 2 ect on the outgoing long-wave radiation ff 4436 4435 O enters the stratosphere primarily in the trop- O are most challenging. Altogether it can be 2 2 O amount in the upper troposphere and lowermost 2 O profiles yield valuable information on the vertical distribu- 2 O mixing ratios over the 1980s and 1990s (e.g., Michelsen et 2 O) is a highly variable atmospheric constituent. It plays a dominant O) is one of the operationally retrieved key species of the Michelson O quantities observed by MIPAS and the validation instruments are 2 2 2 O in the radiatively sensitive UT/LS along with the underlying processes 2 O in the stratosphere with an overall accuracy of about 10 to 30 % and a 2 erences of H O loss reaction with the electronically excited oxygen atom (producing the OH rad- Water vapour is produced in the troposphere mainly by evaporation processes over ff 2 trends in H H ical) becomes only importantyields, along in with the shortwavethe upper mesosphere photodissociation stratosphere and reactions, thermosphere. and to Recenttrend lower research declining in mesosphere has stratospheric H focused and H onal., a 2000; positive Oltmans global et al.,substantial 2000; Rosenlof and et unexpected al., decrease 2001; inyear Nedoluha stratospheric 2000 et water (Randel al., was et 2003) documented al., whereas after 2006; a Scherer the et al., 2008; Fueglistaler, 2012). Understanding which decrease strongly with altitude. H ics through the tropical transitionHowever, layer the (TTL) (see, actual e.g., Brasseur pathwayssphere and of are Solomon, still 2005). water under transport debatemixing from (see, ratios e.g., the are Fueglistaler UT et increasing al., into with 2009). the altitude In lower the due stratosphere, strato- to methane oxidation. The competing Water vapour (H role in the transferin of the energy troposphere, in its the emissionin atmosphere. in the the While stratosphere. infrared it Hence, spectral thestratosphere is region H a (UT/LS) contributes strong has to greenhouse a awhich gas cooling regulates considerable the e globalShine, radiation 1999; budget Solomon of et the al., atmosphere 2010). (see, e.g., Forsterwater and and land surfaces leading to maximum concentrations near the Earth’s surface volume mixing ratio (VMR). Some profiles are characterized by retrieval instabilities. 1 Introduction vertical discontinuities, and frequent horizontal gradients in both temperature and H when comparing HALOE and ACE-FTSand data. the Pronounced correlative deviations instruments betweensphere, occur MIPAS in a the region lowermost whereconcluded stratosphere retrievals that and of MIPAS upper H H tropo- tion of H precision of typically 5these to global 15 and % continuous –the data region well are around within very the the valuablefering tropopause for predicted from retrieved scientific a error MIPAS studies. H number budget, of However, proving in obstacles that such as retrieval boundary and cloud e present in the MIPASB, data to the when satellite compared instruments HALOE(Atmospheric to (Halogen Chemistry Occultation its Experiment, Experiment) Fourier balloon-borne Transform and Spectrometer), ACE-FTS wave counterpart and airborne to MIPAS- sensor the MM- AMSOS (AirborneIn Microwave Stratospheric the Observing mesosphere System). the situation is unclear due to the occurrence of di dependent observations from balloons,have aircraft, been satellites, compared to and European ground-baseddata Space stations comprising Agency the (ESA) version time 4.61sured period operational with from H full July spectral 2002ous resolution. until in No March the significant 2004 lower where biasDi stratosphere MIPAS in mea- (above the the MIPAS H hygropause)mostly well between within about the 15 combinedsphere and total (above 30 about errors km. in 30 km), this a altitude tendency region. towards In a the small upper positive strato- bias (up to 10 %) is Water vapour (H Interferometer for Passive Atmospheric Soundingvironmental (MIPAS) satellite instrument ENVISAT aboard which the1 was March en- launched 2002 into and its operated sun-synchronous until April orbit 2012. on Within the MIPAS validation activities, in- Abstract 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | O 2 O have been 2 O in the strato- 2 O profiles from the 2 O profile comparisons 2 O validation activities for the opera- 2 ermann et al., 2002). ff O measurements were obtained in the 2 O. 2 O is mostly limited to the troposphere and 2 4438 4437 O measurements with high spatial resolution during two mis- orts in validation. Balloon-borne observations are very useful 2 ff O assessment is restricted to the time period from July 2002 until March O are the Sub-Millimeter Radiometer (SMR) aboard the Odin satellite 2 2 O was the Limb Infrared Monitor of the Stratosphere (LIMS) (Fischer et al., 2 O products of version 4.61 provided by the European Space Agency (ESA). 2 O demand large e 2 This paper outlines the results of the MIPAS H The complexity and lifetime of such space instruments along with the importance The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS; Fischer More recently, solar occultation satellite instruments observing H Space-borne instruments which are still in operation and which measure vertical Satellite measurements are essential for monitoring the distribution and trend of H 2004 where MIPAS was operated at full spectral resolution. H lower stratosphere. The use ofposes independent has satellite the measurements great advantage forstatistics that validation for nearly pur- all global seasons coverage is in available. combination with a large tional H It belongs to aperformed series in of a validation consistent studiesal., of manner 2007; MIPAS (Cortesi Wang operational et et products al.,studies, al., which the 2007; 2007; were H Wetzel Payan et et al., al., 2007). 2009; In Ridolfi accordance et with these validation flights is limited special careThis has holds to be also taken for concerninglarger aircraft the horizontal measurements quality regions (e.g. of compared the Falcon to coincidence. Ground-based and balloons LearJet) measurements but which from can distinctly may beinformation lower cover flight on carried altitudes. the out vertical more distribution or of H less continuously, but the the Scanning Imaging1999) Absorption and Spectrometer the Global (SCIAMACHY;(Bertaux Ozone Bovensmann Monitoring et et by al., Occultation al., 1991). ofand It climate Stars measures relevant (GOMOS) a constituents instrument including wide H range of tracers, chemicallyof active H species for validation being capable ofa measuring large accurately a vertical large coverage number at of molecules superior with vertical resolution. Since the number of balloon ment (ACE) instrument on2008), the launched SCISAT-1 in satellite August (Nassar 2003;ney et a et second-generation al., al., MLS 2007; 2005; on Santee Carleer the et Aura et satellite al., al., (Man- 2005) with dataet from al., begin of 2008) mission is in August one 2004. of the three chemistry instruments onboard ENVISAT, besides (Urban et al., 2007), launched in February 2001; the Atmospheric Chemistry Experi- profiles of H 1996) and the Microwave Limb SounderInfrared (MLS) Spectrometers (Pumphrey and et al., Telescopes for 2000). theformed The Cryogenic Atmosphere limb (CRISTA) emission experiment H per- sions of the Space Shuttle in 1994 and 1997sphere (O were the(Nedoluha et Polar al., OzoneSounder 2003; (ILAS/ILAS-II) and (Kanzawa Lumpe et Aerosol al., et 2002; Measurement Griesfeller al., et (POAM) al., 2006) 2008). III and the instrument Improved Limb Atmospheric spectral region (Chiou et al.,visible spectral 1997). range Further by the H Halogenper Occultation Atmosphere Experiment (HALOE) Research aboard Satellite the1996; Up- (UARS) Nedoluha between et 1991 al.,the and 2003). Improved Other 2005 Stratospheric instruments (Harries and on Mesospheric et UARS Sounder al., detecting (ISAMS) (Goss-Custard H et al., aboard the Nimbus-7 satelliteAtmospheric launched Trace in Molecule Spectroscopy October instrument 1978. (ATMOS)tation as In the Fourier the first 1980s transform limb and infrared occul- upper 1990s (FTIR) troposphere the spectrometer to provided theShuttle H lower between mesosphere 1985 during and fourAerosol 1994 short and (Abbas missions Gas et of Experimentand al., the (SAGE provided 1996a, Space II) a b). wastroposphere The 21 launched and second yr into stratosphere Stratospheric record its using of orbit solar in global occultation October trace in 1984 the gas visible measurements and of near-infrared the sunlit upper 2010). on a globalspheric scale. H One of1981; the Russell first III spaceborne et instruments al., able 1984), to a measure limb-emission strato- filter radiometer which was deployed are crucial for understanding and predicting rates of global warming (Solomon et al., 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , 3 O, O 2 ; uncertainty 3 . A random re- O data. 1 2 − erent spectral and ff erent validation instru- , and NH ff 2 erent seasons. The follow- ff V6 data have shown that dif- , ClONO , and 1652 cm 3 1 − with an unapodized full spectral resolution , 1646 cm 1 4440 4439 1 − erences can be around 10 % or larger. − ff ciently well-conditioned, regularization and a priori ffi O data , 947 cm 2 1 − are retrieved individually in the reported sequence. and 2410 cm 2 1 O volume mixing ratios are less than 5 % in the stratosphere − 2 O based on this data and time period is subject of this paper. 2 O column above the uppermost retrieval level; horizontal gradient 2 O, and NO (Fischer et al., 2008). The vertical instantaneous field of view (IFOV) is 2 1 − ,N 4 O operational version 4.61 data analysis has been carried out in four mi- 2 , CH 3 O profile retrieval: pressure-temperature random retrieval errors; spectroscopic data O data users. ects due to assuming a horizontally homogeneous atmosphere for each profile; and The H Level 1B and level 2 processing of data version 4.61 (high spectral resolution mode) After an increasing frequency of problems with the interferometer drive system in late In the following section, an overview of the MIPAS data analysis is given. Section 3 2 2 ff e errors due to the assumption of local thermodynamic equilibrium (LTE) in the upper error variance covariance matrixsources calculated are during estimated the for retrievaling day process. and Further parameter night error errors conditions andH and forward di model errorserrors have due been to taken uncertainties intometric in account the gain, for intensity, instrumental width the line andties shape, position in and assumed of profiles spectral emission of calibration lines;in the inaccuracies; radio- contaminant high-altitude uncertain- species O H next steps, volume mixing ratioHNO (VMR) profiles of the primary target species H crowindows around 808 cm trieval error due to instrument noise is extracted from the diagonal elements of the rameters has been performedKleinert by ESA et using al. thespectra (2007) operational are processors for described analyzed level by using 1bthe a and forward global model Raspollini according fit ettrieval to approach is al. a by performed (2006) non-linear varying on for Gauss-Newton theprocess the procedure. level same has input Since vertical been 2. parameters grid the found Calibrated of information to as re- appeared be the not measurements su and necessaryand the for pressure inversion a at stable retrieval. the In measured a tangent first altitudes step, are temperature retrieved simultaneously. In the and the processing codes. Althoughtion the mode validation data of is this not newfar finished reduced no yet spectral indication and resolu- is of therefore any not significant included deterioration in in this the paper, qualityincluding there of is all so the steps H from raw data to calibrated spectra and profiles of atmospheric pa- spatial sampling of MIPAS since 2005 has posed changes in the calibration scheme The duty cycle of thisfrom so-called 30 optimized % resolution in mode January has 2005 to been 100 steadily % increased from December 2007 on. The di 68 km were recorded (in stepsThe of validation 3 km of below H 45 km) in the full spectral resolution mode. 2003 and beginning 2004 andto upon suspend subsequent the detailed investigations nominaltions. it operations Since was decided January from 2005 Marchplatform until 2004 was April lost) onwards 2012 the for (when instrument detailedtion was the (41 back investiga- communication % to with of operation nominal) the but for at satellite the reduced benefit spectral of resolu- an equivalent improvement in spatial sampling. about 3 km. The1 instrument March was 2002. launched It into10:00 passes its a.m. the local sun-synchronous equator time. orbitin in After by its southwards the ESA direction nominal commissioning on 14.3 measurementing phase times mode each MIPAS each from was orbit day July run approximately at 72 2002 predominantly limb until scans the covering end tangent of altitudes March between 2004. 8 Dur- and H 2 MIPAS operations and H The limb-viewing Fourier transformbeen spectrometer MIPAS designed on to ENVISAT (MIPAS-E)bands operate has between in 685 cm theof mid-infrared 0.025 cm spectral region covering five spectral ferences in retrieved H except in the Antarctic winter where di describes the intercomparison method and thements comparison and to di another retrieval processor. Section 4 gives concluding remarks for MIPAS between version 4.61 and the newly processed ML2PP 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | where 0.5 σ/N O retrievals be- 2 erence of MIPAS ff of both instruments comb σ profile pairs of compared N for erences between measured quanti- ff mean O radiosonde data are compared to x 2 O observations when they exceed these ∆ of a number of profile pairs is calculated 2 4442 4441 mean,rel erence ff x ∆ erence by the mean profile value of the validation ff O profiles observed by airborne and satellite sensors as erence 2 ff ) (1) n I, x O data. In most cases pressure is used as the primary vertical 100%. (2) 2 · − n erence (standard error of the mean, SEM) is given by n I, ff are the precision, systematic or total errors of MIPAS and the val- , (3) M, x 2 I I are VMR values of MIPAS and the validating Instrument at one altitude 1 x mean ( I = σ σ N P x 1 n erences. The mean di x erences in altitude resolution. All di + = N ff ∆ erence and the combined random error helps to validate the precision of 1 N ff n X ff 2 M O observations from ground and H and 1 σ N = and 2 M q M = σ x = erences are displayed together with the combined errors mean mean,rel is the standard deviation (SD). The comparison between the standard deviation of ff x x comb As part of the validation programber of of the balloon chemistry instruments flights aboard carrying ENVISAT a in-situ num- and remote sensing instruments were performed and another instrument is consideredis significant smaller if the than standard the errorversus bias of itself. the the The bias correlative (SEM) comparison instrumentsstatistical between and the comparisons the VMR or di combined totalto systematic error identify in error unexplained biases the in in case thecombined the MIPAS of error H case limits. single of comparisons is appropriate 3.1 Intercomparison of balloon-borne observations sources (e.g. spectroscopic uncertainties)calculated have mean been di included. The uncertaintyσ of the the mean di MIPAS since both terms should be of comparable magnitude. A bias between MIPAS measurement and correspond, in general,parisons, to systematic random errors noise of errors.have For the randomly statistical temperature and com- profile are usedbudget. therefore for Other included the error in H sources theall are precision validation treated (random) studies as part of systematic.tency of This MIPAS (Cortesi operational the approach et trace error was al., gas applied 2007;It products to Payan should et as al., be a 2009; mentionedcharacterized matter Wang for et that of all al., validation consis- not 2007; instruments Wetzel in all et the error same al., detail. 2007). sources However, dominant (as error specified in Sect. 2) could be which are defined as: σ where idation instrument, respectively. Precision errors characterize the reproducibility of a Di ∆ ties of MIPAS andas the validation relative instrument di areobservations expressed is in given as: either absolute units or 3 Intercomparison results In the following sections,well H as H MIPAS version 4.61 H coordinate and the MIPAS averaging kernelsignificant is di applied to the correlative data in case of where level. The mean relative di by dividing the meaninstrument: absolute di ∆ the dominant error sourceserror in ranges typically the between stratosphere 5is % and within and 10 upper 25 % % troposphere. to inand 30 The this %. systematic altitude random The region total components. while error Awith is the their calculated total detailed as magnitudes error discussion the is root of given mean in all square Raspollini error of et random al. components (2006). together atmosphere (above 45 km). Pressure-temperature and spectroscopic data errors are 5 5 25 15 20 10 15 10 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | erence lies ff O is depicted in Fig. 2. 2 . Transitions between 1210 O was analyzed in MIPAS-B 1 2 − O in the stratosphere. The sum 2 N) on 24 September 2002, Kiruna O retrieval and is therefore compa- ◦ 2 have also been used for the data anal- 1 − 4444 4443 band centred at 1595 cm 2 ν erence above 200 hPa pressure altitude (averaged over all alti- O validation is given in Table 1. ff 2 ] is therefore a good measure for the hydrogen budget because 4 O values. This positive bias turns out to be significant with respect to O mixing ratios strongly increase. However, the mean di 2 2 and around 808 and 825 cm produces about two molecules of H 1 N) on 20/21 March 2003, and again from Kiruna on 3 July 2003. MIPAS-B 4 2[CH − ◦ ¨ opfner et al., 2002). A Tikhonov-Phillips regularization approach constrain- + O] 2 [H erence was not more than 14 min. The MIPAS-E profile (see Fig. 1) is in good agree- As a further test we compare also the hydrogen budget. The oxidation chain of the A summary of all MIPAS balloon comparisons to MIPAS-E H A perfect coincidence between MIPAS-B and MIPAS-E could be achieved during the Three validation flights were carried out within 2002 to 2004 with the cryogenic = ff ). Further improvement of the NESR can be achieved by averaging spectra taken at profiles of both MIPAS instruments are within the range of the in-situ measurements at tudes) amounts to 0.13 ppmv (3.0 %). molecule CH H it is a quasibudget conserved as quantity obtained by in both this MIPAS instrumentstions altitude in (Engel comparison region. et to Figure earlier al., 3 in-situratio 1996; observa- displays Herman profiles the et exhibit hydrogen al., largercompared 2002). variations to In (at the general, least MIPAS-E profiles individual retrieved partly mixing from caused MIPAS-B by spectra. retrieval Mean oscillations) inferred mixing ratio For most altitudes, anyis deviation visible above is about within 20low hPa. the where Large the combined deviations H occur errorclearly around limits. within the the A hygropause combined total and positive error, be- 200 except bias hPa. the lowermost The altitude mean region di below about di ment with MIPAS-B betweenexhibits about higher 20 H and 100 hPa.the combined Above systematic these errors above altitudes, aboutsystematic MIPAS-E 7 hPa errors indicating additional there. yet A unidentified The negative altitude bias of is the hygropause visiblebilities is around which captured and occur very frequently well below in by the MIPAS-E. the Some hygropause. ESA retrieval operational insta- data retrieval are also visible. mainly from the HITRAN 2004the database MIPAS-B (Rothman data et analysis al., is 2005). given A in further Wetzel et overview al. on flight (2006) on and references 24 therein. Septemberservations 2002 in above the southern compared altitude France. region The was mean within about distance 200 of km and both the ob- mean time the database taken for the MIPAS-E data analysis (Flaud et al., 2003) and originate and 1245 cm ysis. Spectroscopic parameters chosen for the MIPAS-B retrieval are consistent with grid. Retrieval calculations of atmosphericgrid target parameters with were a performed least at squaresby a fitting the 1 km Karlsruhe algorithm Optimized using and analytical Preciseal., derivative Radiative 2002; transfer spectra H Algorithm calculated (KOPRA; Stiller et ing with respect toresolution the is shape typically of between an 2rable and a to 4 priori or km better for profile than the was the H verticalproven adopted. resolution microwindows The of in MIPAS-E. resulting H the vertical atmospheric parameters covered bythe MIPAS-E. sophisticated Essential line for of the sight stabilizationtion balloon system, system instrument which and is is supplemented based with ondata an an inertial processing additional naviga- star including reference instrument system.al. characterization The (2004) MIPAS-B is and references described therein. in The Friedl-Vallon measurements et were done typically at a 1.5 km (Sweden, 68 can be regarded ascations precursor are of quite MIPAS on similar, such ENVISAT.critical Therefore, as a parameters, spectral number however, resolution of the andof specifi- spectral MIPAS-B the performance coverage. For NESR is some (Noiseaccuracy superior, and Equivalent e.g. precision Spectral in which Radiance), theσ is, and case in in terms the ofthe case tangent same pointing of altitude, angle in the which the pointing is order justified of in 90 the m balloon (3 case. MIPAS-B measures all loon flights used for H Fourier transform infrared spectrometer MIPAS-B, thecovering balloon-borne mid-latitude version of summer, MIPAS, polarflights winter/spring, took and place polar from summer Aire conditions. sur The l’Adour (France, 44 within dedicated campaigns at various geophysical conditions. An overview of all bal- 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | erence of 0.16 ppmv O gradient ff 2 − deviations between 4 ´ etrie Stratospherique) was photofragment fluorescence O profiles from the upper tro- 2 α O profile shown in Fig. 2, since the 2 O and mean CH ¨ 2 oger et al. (1999). ´ eorologie Dynamique) and has been oper- erence H ´ et ff 4446 4445 erences are less than 1 ppmv (20 %) and within ff ¨ ulich and is based on the Lyman- O profiles measured during the FISH flight onboard the TRIPLE bal- erences between MIPAS-E and FISH for this trajectory comparison. 2 ff erences which are barely within the combined total error limits. However, erence between MIPAS and the smoothed FISH profile is only ff O values reveal a slight positive bias increasing with altitude. Anyhow, the ff 2 ects. Above this altitude region, mean deviations are mostly well inside the ff erence profile was calculated taking into account the number of coincident measure- erences are mostly within the combined errors. erence profile is similar to the mean di 2.7 %). For the June 2003 flight, the comparison was restricted to only three altitude A summary of the direct comparison of all balloon flights is given in Fig. 7. A mean The Fast In situ Stratospheric Hygrometer (FISH) has been developed at the Data of two balloon flights have been used for the intercomparison with MIPAS. Both ENVISAT validation flights with ELHYSA were performed on 16 January 2003 and The frost point hygrometer ELHYSA (Etude de L’Hygrom ff ff ff − combined errors. It should beand mentioned MIPAS-E that at the pronounced 24 kmdeviation deviation between is is FISH largely linked comparable to toMIPAS-E H only the combined one precision single errors.mean collocation. Above deviation about The over 27 overall all km, Hence standard altitudes the above 10 general km agreementfound is to between found be balloon-borne to quite good. be observations only and 0.07 MIPAS-E ppmv is (1.7 %). ment sequences. Below about 13all km intercomparisons at is mid quite and large, presumably highaltitude due latitudes, of to the the uncertainties mean tropopause regarding di the andin exact hygropause the in troposphere, as connection well with ascloud the due e strong to sometimes H strong horizontal inhomogeneities and displays mean di Only collocations below aboutson. 50 In hPa this pressure altitudethe altitude range, combined could total mean be errors. di It foundtics is is for noticeable enhanced, that compari- for the thedeviations agreement are upper with generally two MIPAS-E larger altitudes, is than where close the statis- to combined precision perfect. errors. However, standard di the mean di ( levels due to a lacknumber of of FISH matches data between between MIPAS-E andtories about FISH, have 20 been 4-days and calculated forward 60 using and hPa. a backward To increase coincidence trajec- criterion the of small 150 km and 0.5 h. Figure 6 yielding to di loon gondola on 6 March 2003. The MIPAS profile exhibits some retrieval instabilities Forschungszentrum J technique. FISH has beenWith used a in measurement several frequency campaigns of0.13–0.18 ppmv, both 1 and Hz, from the the balloon accuracy noise andand is equivalent the aircraft. mixing 0.15–0.2 calibration ppmv. ratio Further procedure at are details 3 described ppmv of in is the Z instrument flights were performed fromFigure Kiruna 5 shows on H 6 March 2003 and 9 June 2003, respectively. 11 March 2004 frombetween Kiruna. MIPAS and Results ELHYSA are isations displayed quite occur satisfying in in for Fig. the bothdi lowermost 4. flights. stratosphere, The However, especially some overall for devi- agreement the January flight. Anyhow, developed at the LMD (Laboratoireated de routinely M from balloonLPC2E and (Laboratoire airborne de platforms Physiquestratospheric since et balloon 1987; Chimie version acquires it de real-time is l’Environnementposphere in-situ now H et and operated de the by l’Espace). lowervertical The resolution stratosphere of (see, few e.g.,percent. tens Ovarlez of meters and and Ovarlez, with 1994) a with high absolute a accuracy of several and MIPAS-B profiles istitude close regions to are mostly perfect.di within Mean the deviations combined above totalhydrogen and budget errors. is below dominated The by this shape theboth molecule al- of H sensors the are less mean than H 0.4 ppmv in all compared altitudes (Payan et al., 2009). around 7 ppmv. Between 120 hPa and 7 hPa the agreement between mean MIPAS-E 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | O O 2 2 O-DIAL) was flown 2 cult to measure due ffi ¨ uller et al. (2008). ENVISAT O volume mixing ratios between 2 ect the MIPAS retrieval can clearly erences between MIPAS and FISH ff erences. These are being discussed ff ff 4448 4447 erential Absorption Lidar (H ff O was measured in-situ and with remote sensing O line to roughly 1 MHz over the whole bandwidth 2 2 O in regions with very high spatial variability. 2 ¨ uller et al., 2008). erences between both measurement sets are within the com- ff O VMR di 2 The Airborne Microwave Stratospheric Observing System (AMSOS) detects spectral The DLR airborne water vapour Di The hygrometer (FISH) has already been described in Sect. 3.1. An aircraft version in the following sub-sections. Unlessfor maximum otherwise space noted, and time a separation standard of 300 collocation km criterion and 3 h between the observations of is positive at all altitudesbroad with agreement values reaching with 10 the to findingscount 20 from that % AMSOS the above data 30 balloon km. have comparisonsto This been when result other assigned is taking data with in sets into a (cf. dry ac- M bias of 0–20 %3.3 in comparisons Intercomparison of satellite observations Intercomparisons of satellitestatistics sensors allows identifying are potential systematic useful di for cross-validation since the large validation flights were carriedfrom out the in tropics September tostatistical 2002 the analysis covering Arctic, shows a providing a a widebetween mean large latitude deviation 20 between number range and the of 25deviation data collocations km for sets (Fig. altitude, all in 12). direct increasing the collocations The to order found of more between 5 MIPAS than % and AMSOS 15 % measured higher H up. The mean emissions of atmospheric water vapouroptical near spectrometers 183.3 resolve GHz the from H anand aircraft. roughly Two 25 acousto- kHz near theduring line centre. the A flight. single About spectrum 20 is ofFrom measured them every these are 10 integrated integrated to for 15 spectra, improving s about the altitude signal-to-noise 15 profiles km error. to of 60 H kmsurement are method retrieved and along instrument the flight isRetrieval track. given A method in detailed Feist and description et of error al. mea- (2007) analysis and are references therein. discussed in M are most probably not influencedUT/LS, by H high cirrus. Withinbined this error small bars altitude region atthe in the tropopause the upper MIPAS clearly edge shows of a the dry comparable bias altitude (Fig. range 11). whereas around cases, and no clouds were detected above the flight path of the aircraft, MIPAS data be detected with the DIAL. Since spatial and temporal collocation was good for all onboard the Falcon aircraftscription several together times with from anand Forli Kiemle assessment in et of al. October accuracyaround (2008). 2002. Italy is Individual A are given results shown system by of inpoints de- Poberaj the of Fig. et comparison the 10. vertical to Although al. profilemuch in MIPAS (2002) overlap observations higher general with resolution not the than more DIAL MIPAS thanto profile in two validate observations, the MIPAS the MIPAS tropopause data DIAL data regionto has and in a strong is this gradients. thus region In well where addition, adapted clouds water that vapour may is a di of MIPAS with respectof to FISH up in to the 75of % upper coincidences at troposphere in 180 and the hPa. trajectory lowermost However,which match when stratosphere are the taking clearly deviations into are within decreasedthe the account to problem combined the of less systematic increasing validation than error of 10 number % limits. H This example illustrates was flown several times aboarddation the flights high-altitude were M55 performed Geophysica from aircraft. Forliand MIPAS (Italy) vali- March and Kiruna 2003. (Sweden) Figures betweenfor July 8 2002 all and Geophysica 9 flights showdence (Fig. mean within 8) di a and with 300matches 4-days km forward between and and backward MIPAS 3 trajectory and calculationsh h FISH looking (Fig. coincidence within for 9). a limit The coincidence direct in criterion coincidence direct comparison of coinci- exhibits 150 km a significant and negative 0.5 deviation The validation program of thea chemistry number instruments of aboard aircraft ENVISAT flights comprisedinstruments where also within H dedicated campaigns.validation An is overview given in of Table aircraft 2. flights used for H 3.2 Intercomparison of aircraft observations 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | N O 2 ◦ S to 80 ◦ O profiles are displayed in 2 in August 2005. SAGE II was O version 19 data is compared ff 2 O profiles were reported to show 2 O profiles were interpolated to a mean 2 4450 4449 , and aerosol extinction at four infrared wave- 2 O, NO, NO O data seems to reveal a negative bias of about 5 % in the 2 O is retrieved using the 935 nm channel (Chu et al., 1993). 2 2 band. In this study HALOE H ,H 4 2 ν N. H ◦ during each sunrise and sunset with a latitudinal coverage between O 2 2 O data version 6.2 is used for the intercomparison to MIPAS. Preci- erences between MIPAS and HALOE as a function of latitude are given 2 ff S and 80 ◦ , HCl, HF, CH 3 O, and NO 2 erences between MIPAS and SAGE II observed H ff erence is found to be within a 10 % limit for most coincident altitudes except of ,H Di Observed di 3 ff The Atmospheric Chemistry Experiment on theorbit satellite SCISAT-1 in was August launched 2003 into its (Bernath et al., 2005). The primary instrument is a high-resolution the MIPAS data. Thisaccount bias all reaches collocations up and to(see is 10 Fig. % 16). still above The clearly aboutPlease overall within note 40 mean hPa that the deviation the when between SAGE combined taking II MIPASthe systematic comparisons and into HALOE are error SAGE comparisons. confined II limit to a is smaller only altitude 5.0 range %. than 3.3.3 ACE-FTS comparison the altitude range between 15good and 40 agreement km, with SAGE II correlativedecreasing H measurements precision above within 40 10 km. % with a positiveFig. bias 15 and and in Table 4.10 %, Mean deviations showing between a MIPAS and similar SAGE II behaviour are to mostly within the HALOE comparison with a positive bias in Budget Satellite (ERBS)ber was 1984 launched (Mauldin into eta its al., seven-channel non-sun 1985) solar synchronous and occultationinfrared spectral was orbit instrument range. powered It in which collected o Octo- workedO aerosol concentrations in and the data of visibleabout trace 80 gases and like near- In this study, H sion and accuracy of this data version has been assessed by Taha et al. (2004). In 7.5 %. 3.3.2 SAGE II comparison The Stratospheric Aerosol and Gas Experiment II (SAGE II) on the Earth Radiation stratosphere and lower mesosphere. For all collocations the averaged bias amounts to into account all collocationsthe (see combined systematic Fig. error 14). limits Although it the is observed significant bias in is terms well of the within SEM in the upper al. (2000), HALOE V19 H stratosphere. in Fig. 13 anddi in Table 3. The agreementthe between Southern both Hemisphere sensors in mid-latitudesstratosphere. terms where Overall, of the a the deviations mean generalof are slight MIPAS larger compared positive in to bias the HALOE (increasing upper which slightly extends with up altitude) to 12 % can be recognized taking sorption of the H to MIPAS. The validation andal., intercomparison 1996) to of independent previous measurements versionstratosphere has 17 and shown data mesosphere an overall (Harries (30 % accuracy et The of at 10 precision the % upper in in and the theAccording lower measurement lower to boundary). stratosphere an was intercomparison determined study to of be various within instruments a performed few by percent. Kley et 3.3.1 HALOE comparison The Halogen Occultation Experimentboard (HALOE) the Upper was Atmosphere launched Research in2005. Satellite (UARS) The September and experiment 1991 operated used on untilture, November solar O occultation to measurelengths vertical (Russell profiles III of et tempera- over al., the 1993). course The of latitudinal one coverage ranges year. from The 80 channel near 6.6 µm was tuned to detect the ab- both MIPAS and thepressure reference grid instrument over H profiles all measured collocated by the observations. validationby instruments Since averaging is kernels the has comparable been to vertical applied MIPAS no for resolution the smoothing intercomparison of of the H observed profiles. the two involved sensors has been applied. For each of the selected collocation pairs, 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | er- ff N to ◦ 13.8 % is visible. − erences are mostly ff E, 683 m a.s.l.). These ◦ erence of all collocations ff O is one of the key species 2 N, 13.4 ◦ O observations showed relative 2 spectral regions, to infer profiles from 5 to O profiles with small retrieval uncertainties in O VMR gradients in the compared profiles can 4452 4451 1 2 2 − O values at a specific altitude level. Anyhow, the erences in the altitude position of the tropopause 2 ff O version 2.2 data for the comparison to MIPAS. Profile O retrieval utilizes numerous microwindows, located in 2 2 . Profiles of a large number of trace species are retrieved 1 − O values below the hygropause lead to larger absolute di 2 erences in the H ff and 1360–2000 cm 1 − erence of all collocations is displayed in Fig. 18. Di ff S with a majority of observations in the polar region. H erences of about 18 % in the lowermost stratosphere and 30 % in the upper tropo- O profile observations were carried out within a ground-based measurement cam- ◦ In addition, the CNR-IMAA lidar system for water vapour profiling was used for val- For this intercomparison, radiosonde measurements carried out between July 2002 The mean di For the MIPAS versus ACE-FTS comparisons the mean di ff 2 lidar and MIPAS observations can be considered as simultaneous. ences below 12 km which are somewhat larger than theidation combined of total errors. MIPAS. Thiswater lidar vapour instrument profiles from isresolution about capable in 100 of time m and determining, above spaceof the during altitude and station night and with up within a time, to 10 statisticalparisons % 12 km with error within lidar a.s.l. typically 8 profiles, to with within the 12 5it high km same % has criterion altitude up to (Mona as to et for be 8 the al.,integration km kept radiosondes window 2007). in (typically was For of mind adopted, intercom- 10 but that min) water centred around vapour the lidar MIPAS overpass. profiles Therefore are obtained with a temporal resolution of the ground-based measurementsthe comparable satellite to sensor. the vertical resolution of within the combinedStrongly total increasing errors H and an overall negative bias of (Italy). Radiosondes measuringmidity atmospheric were pressure, launched at temperature the Universityprofiles and of were L’Aquila relative (42.4 measured with hu- balloon-borne Vaisala sondes. and March 2004 in coincidence withwith MIPAS temperature overpasses are radiosonde considered. vs. In2007), accordance MIPAS a temperature intercomparisons collocation (Ridolfi criterionhave et been of smoothed al., 300 km with the and averaging 3 kernel h matrix was of established. MIPAS to Observed make profiles the altitude H paign for the validationdi of Metodologie per MIPAS l’Analisi temperature AmbientaleIMAA) and del in water Consiglio Potenza vapour Nazionale (Italy) data delle and Ricerche by the (CNR- the Department Istituto of Physics of the University of L’Aquila 3.4 Intercomparison of ground-based observations and radiosonde data between about 100 hPa andmesosphere 0.5 and hPa below pressure 100 altitude. hPa in However,stratosphere, above the a 0.5 region dry hPa of in bias the the least is upper partly visible troposphere connected in and with the lowermost vertical MIPASand di data. hygropause in Deviations the below profiles. Strong 100 H then hPa lead are to at large di mean negative bias calculated over all altitudeswith is a only large 5.9 %. standard This, deviation however, goes which along exceeds the mean combined precision error. sphere suggesting a systematictroposphere dry in bias winter and of spring the (Hegglin ACE-FTS et data, al., at 2008). over least all for latitudes the is upper shownMIPAS in and Fig. ACE-FTS 17. is For the quite mean good deviation, the over agreement a between large altitude region in the stratosphere 90 km altitude. Here we usecomparisons H of this data versionSMR) to observations space-borne and measurements (SAGE from II,a balloon-borne HALOE, frostpoint ground POAM hygrometers based III, and lidar MIPAS, havethat been ACE-FTS performed measurements by provide Carleer H the et al. stratosphere (2008). of The better authorsaltitude than show region. 5 % However, from adi 15 comparison to to 70 aircraft km, gradually H increasing above this tween 750 and 4400from cm measured spectra with85 a vertical resolution ofprovided 3 by to ACE-FTS. 4 The km H betweenthe about 950–975 cm 85 Fourier transform spectrometer (ACE-FTS) which operates in solar occultation be- 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | a ı O ´ 2 cient erent ff ffi erences in ff O profiles ob- O values near 2 and in the H 2 E) between July 1 O retrievals may ◦ sica de Andaluc 2 − ı ´ erent thresholds of erence of 1 K in the ff ff ected tangent limb view ff N, 15.7 ◦ erences in the temperature ff and 960 cm O mixing ratios for lidar values 1 2 − erence of about 10 % which corresponds . Since profiles are retrieved on a fine ver- O vertical profiles have been compared to ff O has been described by Milz et al. (2005). 1 2 2 − erence between both processors is less than 4454 4453 ff erence between the distribution retrieved with ff erences of more than 1 ppmv occur in the UT/LS ff O retrieval are altitude dependent and are located 2 O VMR di 2 erent lowermost boundaries of the retrievals. and 1655 cm ff O VMR di 1 2 − erences between ESA and IMK/IAA products can arise from the ff O were observed from Potenza (40.6 2 O retrieval calculations have also been performed with the dedicated scien- 2 O deviations are at least partly connected with di 2 0.89 is found. MIPAS underestimates the lidar H = r As shown in various retrieval studies and statistical analyses, H The zonally averaged H Lidar profiles of H -band between 1220 cm 2 parisons is given in Table 5. The objective of thistained study in has the been firstresolution to MIPAS measurements) validate operational by MIPAS period operational comparisonpreviously H July validated to instruments. 2002 independent MIPAS to H measurementsground-based, March of aircraft, balloon-borne, di 2004 and (so-called satellitecomparison observations. full has A also retrieval processor been includedoperational to retrieval better procedure. assess A potential summary inaccuracies of during the the assessment of the individual com- Leicester Thesis, 2007). From thatcan it appears reduce that some using of a thethe more variability tropopause. stringent but cloud does filtering not explain all of the low H 4 Conclusions of both processors occurred forSeptember example 2002 in (Wetzel the et al., mesosphere 2007). andat The upper 100 comparisons stratosphere hPa, in in mainly Fig. 20 sincethe have the been cloud truncated IMK/IAA index and yielding to ESA di processors use di react sensitively to clouds inbut also the on FOV, two not (cloud-free) only layersand above at that ozone the (e.g. in cloud-a Sembhi the H., tropical “Observing UT/LS water with vapour the MIPAS instrument on ENVISAT”, University of regularization used by IMK/IAA while nomore, regularization H has been used byprofiles ESA. Further- retrieved by the processors. Forstratosphere instance, would a temperature result di into a roughly H 0.6 ppmv. Deviations of up to 5 K between the retrieved temperature profiles the season studied. Di and in the Arctic upper stratosphere. Deviation patterns up to about 0.5 ppmv vary with ν tical grid (1 km fromregularization 6 has to been 42 applied km to altitude) avoid independent retrieval of instabilities. the actualthe tangent processors altitudes, by a ESAmonths and is IMK/IAA shown (data intween about version Fig. 100 13) hPa 20. and for 0.5 Over0.5 hPa, a ppmv the wide (less sample di than undisturbed 10 period %). regionsregion Largest of around di in three the the tropopause/hygropause (not stratosphere shown be- in the plot), in the mesosphere, tific IMK/IAA data processor (vonMeteorology Clarmann and et Climate al., Research (IMK) 2003),(IAA). and developed The the at principal Instituto the retrieval de Institute strategy Astrof for Selected for H microwindows for themainly H in the spectral window region between 795 cm comparison. Some deviations are atthe least altitude partly position connected of withinhomogeneities. the vertical No di tropopause seasonal and dependenceobserved. hygropause between in the the data profiles of and both horizontal instruments3.5 is Retrieval processor comparison MIPAS H 2002 and February 2004. Ais total of confined 12 to profiles could theand be 12 narrow used km. for Results overlapping the of altitude comparison thisof which comparison region are of displayed in both Fig.below 19. instruments about A between correlation 20 ppmv coe 5 which corresponds to the upper altitudes in the region of inter- 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ects ff O mean 2 O profiles tend ects from (thin) 2 ff erent spectral regions ff O profiles collected between 2 erent instruments. ff O profiles in the lowermost stratosphere 2 4456 4455 O VMR, (2) large horizontal inhomogeneities, 2 ects might be advantageous there. ff O in the stratosphere such that these data sets are very 2 erences between MIPAS and the validation instruments are ff O data from observations of di O is also obvious in the AMSOS aircraft comparisons and the 2 2 O profiles in this altitude region. O gradient. Any vertical altitude shift results in comparably large 2 Financial support by the DLR (Project 50EE0020) and ESA for the 2 ects caused by improper assumptions of the atmospheric state parameters ff erent biases. Altogether, it can be concluded that MIPAS V4.61 H The validation results are generally in line with the ex ante estimated MIPAS error A critical altitude range for evaluating the validation results is the region of the upper In the lower and middle stratosphere between about 15 and 30 km (above the hy- In the middle and upper stratosphere (above about 10–15 hPa or 28–30 km), a ten- ff the SAGE II groupand at Aerosol Branch NASA for LaRC, providing especially the to data and Larry information Thomason, on and these data. the The NASA validation Radiation work Acknowledgements. MIPAS-B balloon flights isSpatiales (CNES) gratefully balloon acknowledged. launching We teampeople and thank for the excellent the balloon Swedish operations, Space Centre the Corporationcrew DLR National (SSC) flight for Esrange department d’Etudes excellent and the campaignNaujokat) Russian operation Geophysica for and meteorological the(DLR) support Free in University and retrieving ofwas trajectory the Berlin provided calculations. primarily (K. DIAL by Grunow AssistanceEngineering data the Research and by Council Canadian is (NSERC) B. Space C. of greatlyP. Canada. Agency Kiemle Bernath The (CSA) acknowledged. authors and and would Funding like C. theUniversity, to for especially Natural thank Boone K. to Sciences the for Walker, J. and providing M. ACE Russell ACE mission III, data. and We at thank NASA LaRC, the especially HALOE to group E. Thompson, at and Hampton the total error exceedsMIPAS the operational 100 % data limit are abovecodes therefore 65 taking km less into (Raspollini reliable account et above non-LTE e al., the 2006) stratopause. such Dedicated that al., 2006). Theranging estimation from for 5 thedation to random exercise 25 part might %. of also Some bewere the systematic used related error to mixing to derive (precision) spectroscopy, ratio H since typically profile di was deviations inJuly the 2002 vali- and Januaryon 2004 (so global called distribution full ofvaluable resolution for H scientific data) studies. yield In valuable the information mesosphere, MIPAS errors generally increase and profiles and to increased standard deviations in statistical comparisons. limits, particularly within a broadretrieval range of error the stratosphere. (accuracy) The totalsphere had MIPAS und H been upper predicted troposphere, with to largest be errors within near 10 the hygropause to (Raspollini 30 et % in the strato- This yields, of course, to some larger deviations for specific data points in the compared cirrus clouds that aremay not on identified one invalue the hand of cloud deteriorate conclusions screening the drawn procedures. fromIn retrievals, These single the on e comparisons comparisons the or thedetermination those other quality with of hand of a the they limited agreement tropopausetemperature statistics. undermine may and and be the hygropause H which highlydeviations mark dependent and the on biases of sign the the change exact and intercompared in H upper the troposphere. Itto should exhibit retrieval be oscillations, mentioned particularly that in the single region MIPAS of H the tropopause/hygropause. troposphere and lowermostaltitude stratosphere region (around is the certainlyspatial tropopause/hygropause). most gradients This challenging in for temperature(3) any and FOV satellite H E sensor duebelow to the (1) lowermost strong tangent altitude, and (4) straylight and other e MIPAS satellite and MIPAS-B comparisonsrespect can to be the recognized, standard thattotal errors. error is In significant of addition, with the thewet comparison mean in bias the though in hydrogen being budget MIPASsatellite looks H mostly comparisons very within similar. to This HALOE, the SAGEture combined II, is and unclear ACE-FTS. In sincedi the the mesosphere, only the satellite pic- comparisons to HALOE and ACE-FTS exhibit gropause), observed di mostly well within the combinedbias in total the error MIPAS bars. H There is no indication ofdency a towards significant a positive bias that is increasing with altitude (up to about 10 %) in the 5 5 30 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , Geophys. Res. 4 O and CH ` ere, M., Drummond, J. R., 2 , 2008. ¨ el, S., Rozanov, V. V., Chance, , 2007. ` ere, E., Pellinen, R., Korylla, E., Korpela, S., 4458 4457 , Geophys. Res. Lett., 23, 2405–2408, 1996b. ` ere, M., Demoulin, P., Godin-Beekmann, S., Jones, 4 , 2005. doi:10.5194/acpd-8-4499-2008 O and CH 2 ¨ opfner, M., Milz, M., von Clarmann, T., Kivi, R., Valverde-Canossa, doi:10.5194/acp-7-4807-2007 ´ egie, G., Widemann, T., Chassefi doi:10.1029/2005GL022386 ¨ omel, H., Kar, J., H gen budget in the ArcticExperiment, winter stratosphere J. during Geophys. Res., the 101, European Arctic 14495–14503, Stratospheric 1996. Ozone E., Catoire, V., Chance,N., K. 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Centre of the References the SciLoV project.funded The by PON CNR-IMAA 2000–2006, ground-based Misuraactivities II.1, facility were MIUR. supported The for CNR-IMAA by Earth ENVISATreceived ESA/ESTEC calibration/validation from Observation contract No. Italian was 16040/02/NL/SF. “Ministero TheCETEMPS partly dell’Ambiente financial balloon sounding support e activities, della is Tutela gratefully del acknowledged. An Territorio acknowledgement e goes del Mare” for the by IUP-IFE Bremen was funded in part by BMBF (FKZ 01 SF994) and ESA/ESRIN under 5 5 30 25 20 15 10 30 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , 2008. , 1996. (Correc- ´ opez-Puertas, , 2009. ¨ oger, C., and Desh- , 2008. o, J.-L., and Brown, L. 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A., 5 5 30 25 20 30 15 25 10 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | erence 3 h 3 h 3 h 2 h ff < di ≤ ≤ ≤ erence ff 300 km 300 km 300 km 80 km ≤ < ≤ ≤ (at 20 km) di 2051 3403 3390 3404 3411 2881 2896 4649 4935 5214 5250 5386/5387 4466 4465 N 2001 N 3318 N 2865–2868 N 4585 ◦ ◦ ◦ ◦ 35–46 38–50 16–89 61–78 20/21 Mar 20039 Jun 2003 MIPAS-B3 Jul 2003 78/2811 km Mar 2004 FISH 15/24 min MIPAS-B ELHYSA 2 km 312 195 km km 1 28 min min 501 min N) 6 Mar 2003 FISH 192 km 73 min ◦ N) ◦ 18 Oct 2002 23 Oct 2002 24 Oct 2002 25 Oct 2002 17 Sep 2002 18 Sep 2002 19 Sep 2002 18 Jul 2002 22 Jul 2002 24 Oct 2002 15 Jan 2003 19 Jan 2003 8 Feb 2003 28 Feb 2003 2 Mar 2003 12 Mar 2003 LocationKiruna(Sweden, 68 Date 16 Jan 2003 InstrumentAire sur l’Adour ELHYSA Distance(France, 44 24 Sep 2002 532 Time km MIPAS-B 183 min 207/79 km 14/10 min Overview on aircraft flights used for the validation of MIPAS-E. Distances between Overview of balloon flights used for the validation of MIPAS-E. Distances and times O-DIAL 2 (aboard Falcon) AMSOS (aboard Swiss Air Force Learjet) H Instrument DateFISH (aboard Geophysica) Lat. range Orbit Distance Time Table 2. MIPAS-E and the validation instrument refer to the UT/LS region. Table 1. between MIPAS-E and the validation instrument refer to an altitude of 20 km. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ) N Aug 02/03 + erent latitudinal ff erences (MRD, (MIPAS- ff O profiles for di 2 Month of year N erent pressure altitudes (Press. alt.) and ff 4468 4467 1 to 9 %3 to 9 % 8–19 % 9–18 % 27 169 Jan/Mar/Apr 03, July Apr/Jun 02/03 03, July 02/03, Sep 03 4 to 26 %6 to 16 10–34 % %1 to 18 10–35 % % 381 to 12 % 70 6–16 % Jan 03/04, May 03, 8–30 July % 125 Jan 03/04, Feb 03, Nov 387 Apr/May 03 03, July 02/03 July 02–Feb 04 − − − − − − N 100–5 hPa 0 to 9 % 10–17 % 288 July 02–Feb 04 ◦ N 100–0.2 hPa ◦ N 100–5 hPa SSN 100–5 hPa 100–5 hPa 6 to 11 % 100–5 hPa 2 to 12 % 8–16 % 10–22 % 63 29 Dec 03, Feb Jan 04 03/04, Apr/May 03, July 03 Statistics of the MIPAS vs. HALOE comparison of H Same as Table 3 but MIPAS vs. SAGE-II comparison. ◦ ◦ ◦ ◦ SSN 100–0.2 hPaN 100–0.2 hPa 2 to 100–0.2 hPa 18 % 100–0.2 hPa 6–41 % 154 Nov 02–Jan 03, Nov 03–Feb 04 ◦ ◦ ◦ ◦ S–90 S–90 ◦ ◦ 60–90 90 Zone60–90 30–60 Press.30–60 alt. MRD SD N Month of year Zone60–90 28–60 Press.30–60 alt.60–90 90 MRD SD HALOE)/HALOE)), standard deviation (SD), number of collocations within the SZA range ( only matches within the same air mass are included; mean relative di Table 4. regions (Zone). Statistical results are given for di are shown, too. Table 3. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

34

1 10 100 1 to 9 %; positive 5.9 %, larger devi- 2 to 12 %, positive − − − 27 km, mean deviation > erence: erence: erence: ff ff ff combined precision (black (black precision combined σ B (flight no. 11, sequence N3, erences within 10 %, except Arctic upper ff

within 20 % above hygropause bias in Jan 03 and 30 % (direct comparison) comparison within 10 % bias (except around 50 hPa) bias above about 30 km ations around hygropause and in lowersphere, meso- SD generallyprecision errors exceeding combined large standard deviation observed within (large) error bars,dence no seasonal depen- with altitude (up to 20 %) stratosphere and mesosphere O data and independent observations combined precision (black dotted lines) 2 σ O VMR (ppmv) O VMR red squared line) on 24 September 2002 above red squared line) on 24 September 2 H Approx. alt. Comments 18–53 km positive bias above about 30 km,16–60 increasing km16–36 km mean relative di mean relative di 4470 4469 MIPAS-E: 22:07:50UT MIPAS-B: 22:21:42UT rence (red solid line) and 1 Aire: Aire: 24-SEP-2002, F11, Seq. N3 Balloon comparisons (cf. Figs. 1–7) Aircraft comparisons (cf. Figs. 8–12) Satellite comparisons (cf. Figs. 13–17) NH mid/high 9–20 km negative bias in tropopause region, trajectory region low/mid/high mid/high mid/high 0246810 0246810 IMK/IAA vs. ESA Processor versions (cf. Fig. 20) O profiles measured by MIPAS- O profiles measured 2 Ground-based & radiosonde comparisons (cf. Figs. 18–19) O profiles measured by MIPAS-B (flight no. 11, sequence N3, black erence (red solid line) and 1 2 ff

Difference Comb. prec. err. Comb. total err. Jan/Feb/Mar 03 Jul 02–Feb 04 NH mid/high 5–12 km good correlation between both instruments Sep/Oct/Nov 03 NH/SH allFeb 03–Mar 04 15–65 km NH Di mid 6–23 km no significant bias, mean deviation small but erent instruments. Time periods, latitudinal regions, approximate altitudes of -2 0 2 -2 0 2 ff MIPAS-E -MIPAS-E MIPAS-B Difference (ppmv)

1

10 Pressure (hPa) Pressure 100 Comparison of H Quality of the agreement between MIPAS H O-DIAL Oct 02 NH mid 12–17 km some negative deviations near 140 hPa 2 Comparison of H Instrument Time periodMIPAS-B Latitude ELHYSA Sep 02/Mar/Jul 03FISH NH mid/high Jan 03/Mar 04 10–39 km NH small Mar/Jun highFISH 03 positive bias H 10–27 kmAMSOS Jul/Oct NH 02/ high mean deviation within Sep 02 30 %, small 13–27HALOE negative kmSAGE II mean deviation within 20 Jul % 02–Feb (trajectory 04 match) ACE-FTS NH Jul 02–Feb 04 Feb/Mar NH/SH 04 NH/SH NH/SH all 7–70 km mean relative di IMAA Potenza (lidar) ULAQ L’Aquila (radiosondes) dotted lines) and total errors (black dashed lines). lines). (black dashed errors and total dotted lines) black squared line) and MIPAS-E (orbit 2975, southern France along with diffe Fig. 1. squared line) and MIPAS-E (orbitern 2975, France red along squared with line) di on 24 September 2002 above south- Fig. 1. and total errors (black dashed lines). carried out by di Table 5. the intercomparisons together with comments are summarized. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 35 36 1 10 100 10 100                

Mean diff. Mean

MIPAS-E - MIPAS-B MIPAS-E by Engel et performed -3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3 Difference (ppmv) nd MIPAS-B together with 10 100 ed out by Herman et al. (2002) et al. (2002) ed out by Herman sd) O VMR rel. diff. rel. (%) O VMR 2 H ons (solid grey bar) viation (red dotted lines) and the standard -80 -60 -40 -20 0 20 40 60 80 -80 -60 -40 -20 0 20 40 60 80 tted lines) and total (dashed lines) errors. For errors. lines) total (dashed and tted lines) the mean deviation together with precision the mean of all comparisons between MIPAS-E and between MIPAS-E and of all comparisons mean combined errors. Red values indicate the the errors. Red values indicate mean combined Arctic winter 1999/2000 (Herman et al., 2002) 1 10 100 total mean combined error combined mean total 4472 4471                 VMR (ppmv) VMR erences of all comparisons between MIPAS-E and

arisons between MIPAS-E a 4 ff ts (solid dark grey bar) carri MIPAS-E - MIPAS-B, ( MIPAS-B, - MIPAS-E prec. O+2*CH for the statistical analysis. for the statistical analysis. 2 H Arctic winter 1991/1992 (A. Engel et al., 1996) 345678910 345678910 O VMR absolute diff. (ppmv) absolute O VMR 2

10

100

-4 -3 -2 -1 0 1 2 3 4 (hPa) Pressure -4 -3 -2 -1 0 1 2 3 4 H Hydrogen budget of all comp 1 MIPAS-B: Seq. S, 24-09-02, 21:50 21:50 UTC 24-09-02, S, Seq. MIPAS-B: UTC 22:06 24-09-02, 15, Rec. MIPAS-E: UTC 22:05 24-09-02, 14, Rec. MIPAS-E: UTC 22:22 24-09-02, N3, Seq. MIPAS-B: UTC 22:08 24-09-02, 16, Rec. MIPAS-E: UTC 20:56 20-03-03, N3a, Seq. MIPAS-B: UTC 21:10 20-03-03, 20, Rec. MIPAS-E: UTC 08:48 21-03-03, D15c, Seq. MIPAS-B: UTC 09:08 21-03-03, 30, Rec. MIPAS-E: UTC 01:13 03-07-03, 3, Seq. MIPAS-B: UTC 09:39 03-07-03, 06, Rec. MIPAS-E: mean MIPAS-B mean MIPAS-E

10

100 Mean absolute and relative differences erences and combined precision (dotted lines) and total (dashed lines) errors. For Pressure (hPa) Pressure ff

al. (1996) and aircraft measuremen Fig. 3. precision (do absolute differences and combined Arctic winter balloon-borne observati comparison, are shown, too. Mean absolute and relative di Hydrogen budget of all comparisons between MIPAS-E and MIPAS-B together with

Fig. 2. de MIPAS-B (red solid lines) including standard plotted as error bars around error of the mean, lines) dashed (blue and total (blue dotted lines) number of collocations used number

915 absolute di Fig. 3. comparison, Arctic winter balloon-borneal. (1996) observations and (solid aircraft grey measurementsare bar) (solid shown, dark too. performed grey by bar) Engel carried et out by Herman et al. (2002) Fig. 2. MIPAS-B (red solid lines) includingof standard the deviation (red mean, dotted plotted lines) asted and error lines) the bars and standard around total error the (blueof mean dashed collocations deviation lines) used together mean with for combined the precision errors. statistical (blue Red dot- analysis. values indicate the number Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | N) ◦ 68 ∼ 38 10 100

37

10 100 10 100 solute and relative

d with the averaging averaging d with the Difference (%) -40 -20 0 20 40 -40 -20 0 20 40

10 100 tot. mean comb. error comb. mean tot. and the balloon-borne in-situ

Difference (%) -40 -20 0 20 40 -40 -20 0 20 40 Difference (%) -40 -20 0 20 40 -40 -20 0 20 40 e vertical resolution of both N) along with absolute and relative 10 100 tot. mean comb. error comb. tot. mean tot. mean comb. error comb. mean tot. 10 100 ◦ MIPAS-E - FISH (smoothed) - FISH MIPAS-E prec.

68 nd 11 March 2004 (bottom) at Kiruna at Kiruna nd 11 March 2004 (bottom) ∼ MIPAS-E - ELHYSA(smoothed) MIPAS-E prec. MIPAS-E - ELHYSA(smoothed) prec. d line) and ELHYSA (black solid line) and ELHYSA (black solid line) d line) nces (blue squared lines) and combined total nces (blue squared lines) and combined (~68°N) along with ab -2 -1 0 1 2 -2 -1 0 1 2 resolution of both instruments comparable. comparable. resolution of both instruments -2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2

FISH profile was smoothe FISH

in-situ ELHYSA profile was smoothed with the in-situ ELHYSA profile was smoothed

Difference (ppmv)

Difference (ppmv)

Difference (ppmv)

10 100 4474 4473 10 100 10 100 lue squared line) to make th lue squared line) to make erences (blue squared lines) and combined errors (blue ff O profiles measured by MIPAS-E by MIPAS-E O profiles measured 2 O profiles measured by MIPAS-E and the balloon-borne in- 2 O VMR (ppmv)O VMR O VMR (ppmv) O VMR 2 2 H H O profiles from 16 January 2003 (top) a O profiles from MIPAS-E,Jan. 16 2003, 20:51 UT ELHYSA, 16 Jan. 2003, 16:56-19:10UT ELHYSA,Jan. 16 2003, smoothed 2 MIPAS-E, 11 Mar. 2004, 20:50 UT 20:50 MIPAS-E, Mar. 2004, 11 UT 20:22-21:51 11 Mar. 2004, ELHYSA, smoothed 11 Mar. 2004, ELHYSA, 0246810 0246810 0246810 0246810

10 10 Comparison between MIPAS-E (red square Pressure (hPa) Pressure Pressure (hPa) Pressure 100 100 O VMR (ppmv)O VMR 2 H measured H measured Fig. 4. (~68°N) along with absolute and relative differe of MIPAS-E (b kernel averaging errors (blue dotted and dashed lines). The comparable. instruments MIPAS, 6 Mar. 2003, 8:39 UT 8:39 Mar. 2003, MIPAS, 6 FISH, 6 Mar. 2003, 9:32-10:18 UT smoothed 2003, Mar. FISH, 6 0246810 0246810 Direct comparison of H Direct comparison

10 Pressure (hPa) Pressure 100 differences and combined errors. The in-situ in-situ The errors. differences and combined Annotation as per Fig. 4. Fig. 5. FISH on 6 March 2003 at Kiruna instrument the vertical kernel of MIPAS-E to make

O profiles from 16 January 2003 (top) and 11 March 2004 (bottom) at Kiruna ( 2 Direct comparison of H Comparison between MIPAS-E (red squared line) and ELHYSA (black solid line) mea- erences and combined errors. The in-situ FISH profile was smoothed with the averaging ff situ instrument FISH on 6 March 2003 at Kiruna ( Fig. 5. di kernel of MIPAS-E to makeas the per vertical Fig. resolution 4. of both instruments comparable. Annotation Fig. 4. sured H along with absolutedotted and and relative dashed di lines). Theof in-situ MIPAS-E (blue ELHYSA squared profile line) was to smoothed make with the the vertical averaging resolution kernel of both instruments comparable. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

39

Altitude (km) Altitude 40 40 60 80 100 120 140 160 180 200 40 35 30 25 20 15 10                    O profiles measured by O profiles measured by O profiles measured 2 2 MIPAS-E and balloon-

sd) sd) Difference (%)

systematic O VMR Difference (%) Difference VMR O

2

lack solid lines), FISH (green solid lines), lines), FISH (green solid lack solid lines), MIPAS-E - MIPAS-B MIPAS-E - FISH MIPAS-E - ELHYSA MIPAS-E ( - All MIPAS-E prec. mean comb. err. tot.

-60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 ndard error of the mean, plotted as error bars. ndard error of the mean, (hPa) Pressure error of the mean, plotted as error bars. Red error of the mean, 2003 and 9 June 2003 together with combined 2003 and 9 June 2003 together with combined rors (red dashed lines) as well as standard lines) as well as standard dashed rors (red mean combined precision (red dotted lines), mean 10 Mean diff. >10 km: 1.7 ± 2.3 % 2.3 ± 1.7 km: >10 diff. Mean 40 60 80 100 120 140 160 180 200 100 ct comparisons between ct comparisons 4476 4475     tot. mean comb. error comb. mean tot.                (MIPAS-E - Balloon) - (MIPAS-E MIPAS-E - FISH (smoothed), ( (smoothed), - FISH MIPAS-E prec.

(< 150 km and < 0.5 h, trajectory match) trajectory h, km < 0.5 150 and (< d lines) and the standard sd) Difference (ppmv) O VMR DifferenceVMR O H (ppmv) 2 H systematic -2 -1 0 1 2 -2 -1 0 1 2 erences from a trajectory match statistics between H -3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3 ff

40 35 30 25 20 15 10 40 60 80

MIPAS-E - MIPAS-B MIPAS-E - FISH MIPAS-E - ELHYSA MIPAS-E ( - All MIPAS-E prec. tot. mean comb.err. (km) Altitude 100 120 140 160 180 200 Differences of all (red solid lines) dire Pressure (hPa) Pressure H statistics between a trajectory match Mean differences from erences of all (red solid lines) direct comparisons between MIPAS-E and balloon- Mean diff. >10 diff. km:Mean -0.07 0.24 ± ppmv ff Di Mean di

Fig. 7. deviation (red thin dotte and ELHYSA (blue solid lines), together with together lines), and ELHYSA (blue solid and total er lines), dash-dotted (red systematic values indicate the number of collocations. borne observations of the instruments MIPAS-B (b borne observations of the instruments

Fig. 6. MIPAS-E and balloon-borne FISH on 6 March MIPAS-E and balloon-borne FISH on 6 March errors, as well as standard deviation and the sta Annotation as per Fig. 2. 920 Fig. 7. borne observations of theand ELHYSA instruments (blue MIPAS-B solid (black lines),tematic together solid (red with dash-dotted lines), lines), mean and FISH combined total(red precision (green errors thin (red (red solid dotted dotted dashed lines) lines) lines), lines), and asdicate sys- well the the as standard number standard error of deviation of collocations. the mean, plotted as error bars. Red values in- Fig. 6. MIPAS-E and balloon-borne FISH onerrors, as 6 well March as 2003 standardAnnotation and deviation as 9 and per June the Fig. 2003 standard 2. together error of with the combined mean, plotted as error bars.

Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

42 41 50 100 150 200 250 300 50 100 150 200 250 300 350 400         s), and total errors out above Italy and nes) between MIPAS-E

and 3 h together with mean and 3 h together with mean sd) sd) the averaging kernel of MIPAS- of kernel the averaging

Difference (%) Difference (%) Difference

-100 -50 0 50 100 -100 -50 0 50 100 (blue dash-dotted line tot. mean comb. error comb. tot. mean tot. mean comb. error comb. mean tot. -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 (red dotted lines) and the standard error of the standard the lines) and (red dotted rences (red squared li (red rences 50 100 150 200 250 300 50 100 150 200 250 300 350 400 ll Geophysica flights carried 4478 4477 erences (red squared lines) between MIPAS-E and    syst. syst.     ff syst.  ct coincidence limit of 300 km km of 300 ct coincidence limit MIPAS-E - FISH (smoothed), ( (smoothed), - FISH MIPAS-E prec. SH profiles were smoothed with MIPAS-E - FISH (smoothed), ( prec.

(< 150 km and < 0.5 h, trajectory match) h, trajectory < 0.5 km and (< 150 (< 300 km and < 3 h, direct coincidence) direct h, 3 < and km (< 300 Difference (ppmv) Difference Difference (ppmv) Difference -3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3 1----02 4 6 810 -10-8-6-4-20 1----02 4 6 810 -10-8-6-4-20 50 Same as Fig. 8 but for trajectory calculations within a coincidence limit of 150 km and km 150 of limit coincidence a within calculations trajectory for but 8 as Fig. Same

Absolute (left) and relative (right) diffe (right) and relative Absolute (left) 50

100 150 200 250 300

100 150 200 250 300 350 400 Pressure (hPa) Pressure Pressure (hPa) Pressure

Fig. 9. 0.5 h. combined precision (blue dotted lines), systematic dotted (blue precision combined deviation as standard as well lines) dashed (blue northern Sweden within a dire plotted as error bars. FI mean, of collocations. E. Red values indicate the number

and the stratospheric hygrometer FISH for a and the stratospheric hygrometer Fig. 8. Same as Fig. 8 but for trajectory calculations within a coincidence limit of 150 km and Absolute (left) and relative (right) di Fig. 9. 0.5 h. the stratospheric hygrometer FISH forern all Sweden Geophysica within flights a carriedprecision direct out (blue coincidence above dotted Italy limit lines), and of systematiclines) north- 300 (blue as km dash-dotted well and lines), as 3 and standardted total h deviation errors as together (red (blue with dotted error dashed lines) mean bars.values and combined indicate FISH the the standard profiles number error of were of collocations. the smoothed mean, with plot- the averaging kernel of MIPAS-E. Red Fig. 8. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 44

43

60 80 100 120 140 160 180 200 220 240 O-DIAL 2 O-DIAL obser- 2   O-DIAL smoothed O-DIAL, 2 2

(green triangles). H H V4.61 MIPAS V4.62 MIPAS O VMR (ppmv) O VMR (ppmv) 2 2 H H MIPAS Orbit 3390 23-OCT-2002 3390 23-OCT-2002 Orbit MIPAS °E 4.4 °N, 42.7 UTC, 21:55 MIPAS Orbit 3411 25-OCT-2002 3411 25-OCT-2002 Orbit MIPAS 50.09:33 °N,UTC, 10.4 °E 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20

sd) 60 80 60 80

100 120 140 160 180 200 220 240 100 120 140 160 180 200 220 240

rnel of MIPAS. O VMR rel. diff. rel. (%) O VMR 2 H one case, version 4.62 -80 -60 -40 -20 0 20 40 60 80 -80 -60 -40 -20 0 20 40 60 80 O-DIAL, ( 2

e standard error of the mean, plotted as error

60 80 100 120 140 160 180 200 220 240 ons between MIPAS and smoothed H 4480 4479   O VMR (ppmv) O VMR (ppmv) 2 2 H H ith the averaging ke averaging ith the MIPAS - H MIPAS error combined mean total MIPAS Orbit 3404 24-OCT-2002 3404 24-OCT-2002 Orbit MIPAS °E 13.2 °N, 37.7 UTC, 21:23 MIPAS Orbit 3318 18-OCT-2002 3318 18-OCT-2002 Orbit MIPAS 16.1°E °N, 37.7 UTC, 21:11 0 2 4 6 8 101214161820 0 2 4 6 8 101214161820 O-DIAL profiles (blue solid lines and circles) and MIPAS

60 80 60 80

2 with mean combined total errors (blue dashed lines) as well as well lines) (blue dashed errors combined total with mean

100 120 140 160 180 200 220 240 100 120 140 160 180 200 220 240 MIPAS and circles) lines and solid (blue O-DIAL profiles 2 triangles) and, in Mean difference: ppmv (-17.4%) Mean -1.13 the number of collocations. the number

O VMR (ppmv) VMR O (ppmv) VMR O O VMR absolute diff. (ppmv) absolute O VMR 2 2 2 erences of all comparisons between MIPAS and smoothed H H H ff -4 -3 -2 -1 0 1 2 3 4 -4 -3 -2 -1 0 1 2 3 4 H Mean differences of all comparis differences Mean MIPAS Orbit 3318 18-OCT-2002 3318 18-OCT-2002 Orbit MIPAS 21:1142.3 UTC, °N, 15.2 °E MIPAS Orbit 3404 24-OCT-2002 3404 24-OCT-2002 Orbit MIPAS °E 12.3 °N, 42.4 UTC, 21:23 60 80

0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20

100 120 140 160 180 200 220 240 6060 8080 60 80

100100 120120 140140 160160 180180 200200 220220 240240 100 120 140 160 180 200 220 240 (hPa) Pressure

Comparison of observed H Pressure (hPa) Pressure Pressure (hPa) Pressure Comparison of observed H Mean di

Fig. 11. observations (red circles) together as standard deviation (red dotted lines) and th bars. Red values indicate O data points version 4.61 (red w O-DIAL profiles have been smoothed 2 2

Fig. 10. H H O data points versionO-DIAL 4.61 profiles (red have been triangles) smoothed and, with in the one averaging kernel case, of version MIPAS. 4.62 (green triangles). 2 2 925 vations (red circles) togetherstandard with deviation (red mean dotted combined lines)Red total and values errors the indicate standard (blue the error number dashed of of lines) the collocations. as mean, well plotted as as error bars. Fig. 11. H H Fig. 10.

Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

45 O profiles 0.1 1 10 100 1000 0.1 1 10 100 1000 2 60 55 50 45 40 35 30 25 20 15 46 O profiles as measured O profiles as measured 2

O VMR atto-28° (38) -60° O VMR O VMR atto-60° -90° (154)O VMR 2 2 ean combined precision (black (black precision ean combined (MIPAS - HALOE) / HALOE(MIPAS [%] (MIPAS - HALOE) / HALOE(MIPAS [%] mean comb. err. prec. mean dev. rel. ± SEM SD mean err. comb. sys. mean comb. err. prec. mean dev. rel. ± SEM SD mean err. comb. sys. Comparison of H Comparison of H error O measurements for all available 28 28 for all available O measurements  2 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 1 1 MIPAS - AMSOS (all) MIPAS - AMSOS MIPAS - AMSOS (mean) 2 10 10 0.1 0.1

100 100

1000 1000 O measurements for all available 28 direct

Pressure [hPa] Pressure Pressure [hPa] Pressure 2 uthern (right) hemisphere for different latitude latitude different for hemisphere (right) uthern

) are plotted, too.

solid line). Individual comparisons: blue dotted solid line). Individual comparisons:

4482 4481 e standard error of the mean) of H e standard error of the mean) 0.1 1 10 100 1000 0.1 1 10 100 1000 Mean Difference (%) lack dashed lines deviation (red dotted lines) and m

O VMR at O 30° VMR 60° to (70) O VMR at O 60° VMR 90° to (125) 2 2 erence: magenta solid line). Individual comparisons: blue dotted lines, ff (MIPAS - (MIPAS HALOE) / HALOE [%] (MIPAS - HALOE) / HALOE [%] mean rel. dev. ± SEM SD mean comb. err. sys. mean comb. prec. err. mean rel. dev. ± SEM SD mean comb. err. sys. mean comb. prec. err. Comparison of H Comparison of H 2-0 1020304050 -20-100 2-0 1020304050 -20-100

standard deviation: red dashed lines. 60 55 50 45 40 35 30 25 20 15 Comparison between MIPAS and AMSOS H and Comparison between MIPAS

 4-02-0 10203040 -40-30-20-100 4-02-0 10203040 -40-30-20-100 4-02-0 10203040 -40-30-20-100 10203040 -40-30-20-100 Altitude (km) Altitude Mean relative deviation (including th 1 1 10 10 0.1 0.1

100 100

1000 1000

Pressure [hPa] Pressure Pressure [hPa] Pressure Mean relative deviation (including the standard error of the mean) of H Comparison between MIPAS and AMSOS H

Fig. 12. direct collocations (mean difference: magenta difference: magenta direct collocations (mean lines, 2 erent latitude regions (red solid lines). Standard deviation (red dotted lines) and mean

Fig. 13. and so (left) by MIPAS and HALOE in the northern errors (b dotted lines) and systematic regions (red solid lines). Standard ff standard deviation: red dashed lines. σ 930 as measured by MIPASfor and di HALOE incombined the precision (black Northern dotted (left) lines)too. and and systematic Southern errors (black (right) dashed Hemisphere lines) are plotted, Fig. 13. collocations (mean di 2 Fig. 12. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

47

1 10 100 1000 1 10 100 1000 O profiles as 0.1 1 10 100 1000 2 48 O profiles as measured 2

O VMR atto-60° -90° (63)O VMR O VMR at -28° to -60° (29) -60° to -28° at VMR O 2 2 misphere for different latitude for different misphere (MIPAS - SAGE II) / SAGE(MIPAS II [%] (MIPAS - SAGE II) / SAGE II [%] - SAGE II) / (MIPAS mean dev. rel. ± SEM SD mean err. comb. sys. mean comb. err. prec. mean dev. ± SEM rel. SD err. mean comb. sys. mean err. comb. prec. Comparison of H Comparison of H -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 1 1 10 10

100 100

1000 1000

Pressure [hPa] Pressure [hPa] Pressure mean diff.:7.5 ± 1.2 %

4484 4483 O VMR atO -90° VMR to (387) 90° 2 e standard error of the mean) of H of the mean) e standard error 1 10 100 1000 1 10 100 1000 (left) and southern (right) he O profiles as measured by MIPAS and HALOE for all by MIPAS and O profiles as measured O profiles as measured by MIPAS and HALOE for all 2 2 (MIPAS - HALOE) / HALOE [%] HALOE - HALOE) / (MIPAS

mean comb. prec. err. prec. comb. mean mean rel. dev. ± SEM ± dev. rel. mean SD mean err. comb. sys. Comparison of H O VMR at 60°to 90°(169)VMR O O VMR at30° to 60° (27) O VMR 2 2 (MIPAS - SAGE II) / SAGE II [%] (MIPAS - SAGE II) / SAGE(MIPAS II [%] 4-02-0 10203040 -40-30-20-100 4-02-0 10203040 -40-30-20-100 mean rel. dev. ± SEM SD mean comb. err. sys. mean comb. prec. err. mean dev. rel. ± SEM SD mean err. comb. sys. mean comb. err. prec. Comparison of H 1 Comparison of H 10 0.1 100

1000

-40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40 Mean relative deviation (including th 1 1 Pressure [hPa] Pressure 10 10

100 100

1000 1000

Pressure [hPa] Pressure Mean relative deviation of H [hPa] Pressure Mean relative deviation of H Mean relative deviation (including the standard error of the mean) of H regions. Annotation as per Fig. 13. Fig. 15. by MIPAS and SAGE II in the northern erent latitude regions. Annotation as per Fig. 13.

Fig. 14. collocations (387). Annotation as per Fig. 13. collocations (387). Annotation as per Fig. 13. ff Fig. 15. measured by MIPAS anddi SAGE II in the Northern (left) and Southern (right) Hemisphere for collocations (387). Annotation as per Fig. 13. Fig. 14. 935 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

50

49

1 10 100 1000 0.01 0.1 1 10 100 1000 of the mean) of MIPAS and of MIPAS of the mean) N in February and March 2004. ◦ S and 85° N in February and March mean dev. rel. ± SEM SD err. sys. comb. mean mean comb.prec. err. O: All Latitudes (n=166) 2 mean diff.: 5.0 ± 1.2 % S and 85 expected combined precision error over most most precision error over expected combined ◦ titude range as compared to the SAGE-II to the as compared titude range the hygropause region below 100 hPa pressure 4486 4485 O VMR at -90°O VMR to 90° (288) 2 O profiles as measured by MIPAS and SAGE II for all O profiles as measured O profiles as measured by MIPAS and SAGE II for all ncluding the standard error 2 2 Relative DifferenceRelative (%) (MIPAS (MIPAS - SAGE II) / SAGE II [%] mean comb. err. prec. meandev. rel. ± SEM SD mean err. comb. sys. erence (including the standard error of the mean) of MIPAS and ACE- Comparison ofComparison H ff mean diff.: -5.9 ± 4.4 % (MIPAS -(MIPAS ACE-FTS)/ACE-FTS H -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 4-02-0 10203040 -40-30-20-100 4-02-0 10203040 -40-30-20-100 O profiles (166 collocations) between 85° 1 2 1 10 10 erences appear mainly in the hygropause region below 100 hPa pressure alti- 0.1 100 100 ff

0.01 1000 1000

Mean relative difference (i Pressure [hPa] Pressure Pressure (hPa) Pressure Mean relative deviation of H Mean relative deviation of H Mean relative di O profiles (166 collocations) between 85 2

Fig. 17. ACE-FTS H in differences appear mainly 2004. Systematic the altitude. The standard deviation is exceeding Annotation as per Fig. 13. comparisons. altitudes. Please note the much broader al the much note altitudes. Please collocations (288). Annotation as per Fig. 13. collocations (288). Annotation as per Fig. 13. Fig. 16. FTS H tude. The standard deviationaltitudes. is Please exceeding note the theisons. much expected Annotation broader combined as per altitude precision Fig. range error 13. as over compared most to the SAGE-II compar- Fig. 17. Systematic di collocations (288). Annotation as per Fig. 13. Fig. 16. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

52

Pressure (hPa) Pressure 51 1000 100 10 1 1 10 100 MIPAS and 12 lidar soundings erences below 12 km; red squares: ff O VMR Difference (%) Difference VMR O ing 2002 and 2004, together with 2 (MIPAS-ULAQ)/ULAQ12 km) (< (MIPAS-ULAQ)/ULAQ12 km) (> comb. err. mean tot. with is calculated for all data points. -200 0 200 -200 0 200 is calculated for all data points. points. all data for is calculated r r Mean diff.Mean % ± > 12 km: 10.9 -13.8

1 10 cient 100 Black squares: differences below 12 km; red squares: differences below 12 km; Black 4488 4487 ffi O Lidar (ppmv) 2 H (MIPAS - ULAQ)(MIPAS O mixing ratios measured by ratios measured O mixing 2 O profiles measured by MIPAS and thirteen radio soundings O profiles measured O profiles measured by MIPAS and thirteen radio soundings O mixing ratios measured by MIPAS and 12 lidar soundings 2 2 2 ila, performed in winter/spr ila, performed

A correlation coefficient r = 0.89 MIPAS-ULAQ (< 12 km) 12 (< MIPAS-ULAQ km) 12 (> MIPAS-ULAQ err. comb. mean tot. with CNR-IMAA Tito Scalo - Potenza, Italy: MIPAS vs. Lidar Scalo - Potenza, Italy: MIPAS vs. CNR-IMAA Tito O VMR DifferenceO VMR (ppmv) H 2 1 10 100 1000 1 10 100 1000 H Mean diff.Mean km: ± > 12 ppmv -10.2 3.2 1 10 100

-100-80 -60 -40 -20 0 20 40 60 80 100 -100-80 -60 -40 -20 0 20 40 60 80 100

1000 1

Differences between H 2 10 erences between H

O MIPAS (ppmv) MIPAS O H Correlation between H 100 Pressure (hPa) Pressure ff Correlation between H Di

Fig. 18. of the University of L’Aqu bars. plotted as error total errors, combined squares: differences above 12 km.

Fig. 19. July 2002 and February 2004. Green line by the CNR-IMAA in Potenza between performed denotes the 1:1 diagonal. erences above 12 km. ff performed by the CNR-IMAAdenotes the in 1 Potenza : 1 between diagonal. July A 2002 correlation coe and February 2004. Green line Fig. 19. di of the Universitybined of total L’Aquila, errors, performed plotted in as winter/spring error bars. 2002 Black and squares: 2004, di together with com- Fig. 18. 940 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 53

ppmv 2 1 0 -1 -2 0.1 1 10 100 cept of the Arctic cessors for the Sept. to Nov. cessors for O VMR distributions in the 100hPa to 0.1 2 ppmv (or about 10%) ex ppmv O VMR distributions in the 100 hPa to 0.1 hPa undary of the MIPAS measurement range. undary of the MIPAS measurement 2 4489

sh colours negative deviations. negative deviations. sh colours Latitude (deg) ved by the ESA and IMK/IAA pro H2O, ESA - IMK, Sep.-Nov. 2003 - IMK, Sep.-Nov. H2O, ESA 8-04-0 20406080 -80-60-40-200 8-04-0 20406080 -80-60-40-200 1 10 Difference of global zonally averaged H 0.1

100

erence of global zonally averaged H Pressure (hPa) Pressure ff Di

Fig. 20. hPa altitude range as retrie 2003 period. Deviations are mostly within 0.25 2003 period. Deviations are mostly Reddish colours denote positive and blui Reddish colours denote positive upper stratosphere and towards the upper bo Fig. 20. altitude range as retrieved by the2003 ESA period. and IMK/IAA Deviations processors are forper the mostly stratosphere September within and to towards 0.25 November ppmv thecolours (or upper denote boundary about positive of and 10 %) bluish the colours except MIPAS measurement negative of range. deviations. the Reddish Arctic up-