The Impact of Positive Definite Moisture Advection and Low-Level
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Water Vapour Transport to the High Latitudes: Mechanisms And
Water vapour transport to the high latitudes : mechanisms and variability from reanalyses and radiosoundings Ambroise Dufour To cite this version: Ambroise Dufour. Water vapour transport to the high latitudes : mechanisms and variability from reanalyses and radiosoundings. Earth Sciences. Université Grenoble Alpes, 2016. English. NNT : 2016GREAU042. tel-01562031 HAL Id: tel-01562031 https://tel.archives-ouvertes.fr/tel-01562031 Submitted on 13 Jul 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THÈSE Pour obtenir le grade de DOCTEUR DE L’UNIVERSITÉ DE GRENOBLE Spécialité : Sciences de la Terre et de l’Environnement Arrêté ministériel : 7 août 2006 Présentée par Ambroise DUFOUR Thèse dirigée par Olga ZOLINA préparée au sein du Laboratoire de Glaciologie et Géophysique de l’Environnement et de l’École Doctorale Terre, Univers, Environnement Transport de vapeur d’eau vers les hautes latitudes Mécanismes et variabilité d’après réanalyses et radiosondages Soutenue le 24 mars 2016, devant le jury composé de : M. Christophe GENTHON Directeur de recherche, LGGE, Président M. Stefan BRÖNNIMANN Professeur, Université de Berne, Rapporteur M. Richard P. ALLAN Professeur, Université de Reading, Rapporteur Mme Valérie MASSON-DELMOTTE Directrice de recherche, LSCE, Examinatrice M. -
Heat Advection Processes Leading to El Niño Events As
1 2 Title: 3 Heat advection processes leading to El Niño events as depicted by an ensemble of ocean 4 assimilation products 5 6 Authors: 7 Joan Ballester (1,2), Simona Bordoni (1), Desislava Petrova (2), Xavier Rodó (2,3) 8 9 Affiliations: 10 (1) California Institute of Technology (Caltech), Pasadena, California, United States 11 (2) Institut Català de Ciències del Clima (IC3), Barcelona, Catalonia, Spain 12 (3) Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain 13 14 Corresponding author: 15 Joan Ballester 16 California Institute of Technology (Caltech) 17 1200 E California Blvd, Pasadena, CA 91125, US 18 Mail Code: 131-24 19 Tel.: +1-626-395-8703 20 Email: [email protected] 21 22 Manuscript 23 Submitted to Journal of Climate 24 1 25 26 Abstract 27 28 The oscillatory nature of El Niño-Southern Oscillation results from an intricate 29 superposition of near-equilibrium balances and out-of-phase disequilibrium processes between the 30 ocean and the atmosphere. Several authors have shown that the heat content stored in the equatorial 31 subsurface is key to provide memory to the system. Here we use an ensemble of ocean assimilation 32 products to describe how heat advection is maintained in each dataset during the different stages of 33 the oscillation. 34 Our analyses show that vertical advection due to surface horizontal convergence and 35 downwelling motion is the only process contributing significantly to the initial subsurface warming 36 in the western equatorial Pacific. This initial warming is found to be advected to the central Pacific 37 by the equatorial undercurrent, which, together with the equatorward advection associated with 38 anomalies in both the meridional temperature gradient and circulation at the level of the 39 thermocline, explains the heat buildup in the central Pacific during the recharge phase. -
Moisture Transport in Observations and Reanalyses As a Proxy for Snow
Moisture transport in observations and reanalyses as a proxy for snow accumulation in East Antarctica Ambroise DufourIGE, Claudine CharrondièreIGE, and Olga ZolinaIGE, IORAS IGEInstitut des Géosciences de l’Environnement, CNRS/UGA, Grenoble, France IORASP. P. Shirshov Institute of Oceanology, Russian Academy of Science, Moscow, Russia Correspondence to: Ambroise DUFOUR ([email protected]) Abstract. Atmospheric moisture convergence on ice-sheets provides an estimate of snow accumulation which is critical to quantify sea level changes. In the case of East Antarctica, we computed moisture transport from 1980 to 2016 in five reanalyses and in radiosonde observations. Moisture convergence in reanalyses is more consistent than net preciptation but still ranges from 72 5 to 96 mm per year in the four most recent reanalyses, ERA Interim, NCEP CFSR, JRA 55 and MERRA 2. The representation of long term variability in reanalyses is also inconsistent which justified the resort to observations. Moisture fluxes are measured on a daily basis via radiosondes launched from a network of stations surrounding East Antarc- tica. Observations agree with reanalyses on the major role of extreme advection events and transient eddy fluxes. Although assimilated, the observations reveal processes reanalyses cannot model, some due to a lack of horizontal and vertical resolu- 10 tion especially the oldest, NCEP DOE R2. Additionally, the observational time series are not affected by new satellite data unlike reanalyses. We formed pan-continental estimates of convergence by aggregating anomalies from all available stations. We found statistically significant trends neither in moisture convergence nor in precipitable water. 1 Introduction East Antarctica stores the equivalent of 53.3 m of sea level rise out of the 58.3 for the whole continent (Fretwell et al., 2013). -
Seasonal Cycle of Idealized Polar Clouds: Large Eddy
ESSOAr | https://doi.org/10.1002/essoar.10503204.1 | CC_BY_NC_ND_4.0 | First posted online: Tue, 9 Jun 2020 15:35:29 | This content has not been peer reviewed. manuscript submitted to Journal of Advances in Modeling Earth Systems 1 Seasonal cycle of idealized polar clouds: large eddy 2 simulations driven by a GCM 1 2;3 2 4 3 Xiyue Zhang , Tapio Schneider , Zhaoyi Shen , Kyle G. Pressel , and Ian 5 4 Eisenman 1 5 National Center for Atmospheric Research, Boulder, Colorado, USA 2 6 California Institute of Technology, Pasadena, California, USA 3 7 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA 4 8 Pacific Northwest National Labratory, Richland, Washington, USA 5 9 Scripps Institution of Oceanography, University of California, San Diego, California, USA 10 Key Points: 11 • LES driven by time-varying large-scale forcing from an idealized GCM is used to 12 simulate the seasonal cycle of Arctic clouds 13 • Simulated low-level cloud liquid is maximal in late summer to early autumn, and 14 minimal in winter, consistent with observations 15 • Large-scale advection provides the main moisture source for cloud liquid and shapes 16 its seasonal cycle Corresponding author: X. Zhang, [email protected] {1{ ESSOAr | https://doi.org/10.1002/essoar.10503204.1 | CC_BY_NC_ND_4.0 | First posted online: Tue, 9 Jun 2020 15:35:29 | This content has not been peer reviewed. manuscript submitted to Journal of Advances in Modeling Earth Systems 17 Abstract 18 The uncertainty in polar cloud feedbacks calls for process understanding of the cloud re- 19 sponse to climate warming. -
Contribution of Horizontal Advection to the Interannual Variability of Sea Surface Temperature in the North Atlantic
964 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 33 Contribution of Horizontal Advection to the Interannual Variability of Sea Surface Temperature in the North Atlantic NATHALIE VERBRUGGE Laboratoire d'Etudes en GeÂophysique et OceÂanographie Spatiales, Toulouse, France GILLES REVERDIN Laboratoire d'Etudes en GeÂophysique et OceÂanographie Spatiales, Toulouse, and Laboratoire d'OceÂanographie Dynamique et de Climatologie, Paris, France (Manuscript received 9 February 2002, in ®nal form 15 October 2002) ABSTRACT The interannual variability of sea surface temperature (SST) in the North Atlantic is investigated from October 1992 to October 1999 with special emphasis on analyzing the contribution of horizontal advection to this variability. Horizontal advection is estimated using anomalous geostrophic currents derived from the TOPEX/ Poseidon sea level data, average currents estimated from drifter data, scatterometer-derived Ekman drifts, and monthly SST data. These estimates have large uncertainties, in particular related to the sea level product, the average currents, and the mixed-layer depth, that contribute signi®cantly to the nonclosure of the surface tem- perature budget. The large scales in winter temperature change over a year present similarities with the heat ¯uxes integrated over the same periods. However, the amplitudes do not match well. Furthermore, in the western subtropical gyre (south of the Gulf Stream) and in the subpolar regions, the time evolutions of both ®elds are different. In both regions, advection is found to contribute signi®cantly to the interannual winter temperature variability. In the subpolar gyre, advection often contributes more to the SST variability than the heat ¯uxes. It seems in particular responsible for a low-frequency trend from 1994 to 1998 (increase in the subpolar gyre and decrease in the western subtropical gyre), which is not found in the heat ¯uxes and in the North Atlantic Oscillation index after 1996. -
Lecture 18 Condensation And
Lecture 18 Condensation and Fog Cloud Formation by Condensation • Mixed into air are myriad submicron particles (sulfuric acid droplets, soot, dust, salt), many of which are attracted to water molecules. As RH rises above 80%, these particles bind more water and swell, producing haze. • When the air becomes supersaturated, the largest of these particles act as condensation nucleii onto which water condenses as cloud droplets. • Typical cloud droplets have diameters of 2-20 microns (diameter of a hair is about 100 microns). • There are usually 50-1000 droplets per cm3, with highest droplet concentra- tions in polluted continental regions. Why can you often see your breath? Condensation can occur when warm moist (but unsaturated air) mixes with cold dry (and unsat- urated) air (also contrails, chimney steam, steam fog). Temp. RH SVP VP cold air (A) 0 C 20% 6 mb 1 mb(clear) B breath (B) 36 C 80% 63 mb 55 mb(clear) C 50% cold (C)18 C 140% 20 mb 28 mb(fog) 90% cold (D) 4 C 90% 8 mb 6 mb(clear) D A • The 50-50 mix visibly condenses into a short- lived cloud, but evaporates as breath is EOM 4.5 diluted. Fog Fog: cloud at ground level Four main types: radiation fog, advection fog, upslope fog, steam fog. TWB p. 68 • Forms due to nighttime longwave cooling of surface air below dew point. • Promoted by clear, calm, long nights. Common in Seattle in winter. • Daytime warming of ground and air ‘burns off’ fog when temperature exceeds dew point. • Fog may lift into a low cloud layer when it thickens or dissipates. -
Observational Study of a Diurnal Mesoscale Convective Complex
CRARP 25-02 OBSERVATIONAL STUDY OF A DIURNAL MESOSCALE CONVECTIVE COMPLEX David Novak1 and Edward Shimon National Weather Service Forecasting Office Duluth, Minnesota 1. Introduction The Mesoscale Convective Complex (MCC) has been described by Maddox (1980), Bosart and Sanders (1981), and Maddox (1983) as a unique class of intense convection organized on the meso-alpha scale, which occurs primarily in the central United States during the convective season. Fritsch et al. (1981) and Wetzel (1983) showed that MCCs produce locally intense rainfall, large hail, and damaging winds, requiring coincident operational warnings of both severe weather and flash flooding. In contrast to most convection MCCs are distinctly nocturnal (Maddox 1983). Augustine and Caracena (1994) as well as McAnelly and Cotton (1986) have shown that MCCs commence from afternoon thunderstorms in the western Great Plains that organize and continue to develop at night into MCCs. Physically, this nocturnal preference has been linked to the Low Level Jet (LLJ) (Maddox 1980; Wetzel 1983; Maddox 1983), which enhances warm air advection and the flux of moist, unstable air into the system. Composites from Maddox (1983) confirm that MCCs reach maximum size around local midnight, corresponding with the strongest LLJ, and weaken during the morning hours when the LLJ typically weakens (Fig. 1). In contrast to this widely confirmed characteristic of MCCs, convection on 14 August 2000 organized during the early morning in eastern North Dakota, reached maximum intensity and organization during the day across northern Minnesota and northern Wisconsin, and then slowly weakened during the early morning hours of 15 August in central Wisconsin. -
Oak Lawn Tornado 1967 an Analysis of the Northern Illinois Tornado Outbreak of April 21St, 1967 Oak Lawn History
Oak Lawn Tornado 1967 An analysis of the Northern Illinois Tornado Outbreak of April 21st, 1967 Oak Lawn History • First Established in the 1840s and 1850s • School house first built in 1860 • Immigrants came after the civil war • Post office first established in 1882 • Innovative development plan began in 1927 • Population exponentially grew up to the year of 1967 Path of the Storm • The damage path spanned from Palos, Illinois (about 2-3 miles west/southwest of Oak Lawn) to Lake Michigan. With the worst damage occurring in the Oak Lawn area. Specifically, the corner of 95th street and Southwest Highway • Other places that received Significant damage includes: 89th and Kedzie Avenue 88th and California Avenue Near the Dan Ryan at 83rd Street Timing (All times below are in CST on April 21st, 1967) • 8 AM – Thunderstorms develop around the borders of Iowa, Nebraska, Kansas, and Missouri • 4:45 PM – Cell is first indicated on radar (18 miles west/northwest of Joliet) • 5:15 PM – rotating clouds reported 10 miles north of Joliet • 5:18 PM – Restaurant at the corner of McCarthy Road and 127th Street had their windows blown out • 5:24 PM – Funnel Cloud reported (Touchdown confirmed) • 5:26 PM – Storm continues Northeast and crosses Roberts Road between 101st and 102nd streets • 5:32 PM - Tornado cause worst damage at 95th street and Southwest highway • 5:33 PM – Tornado causes damage to Hometown City Hall • 5:34 PM – Tornado passes grounds of Beverly Hills Country Club • 5:35 PM – Tornado crosses Dan Ryan Expressway and flips over a semi • 5:39 PM – Tornado passes Filtration plant at 78th and Lake Michigan and Dissipates Notable Areas Destroyed •Fairway Supermarket •Sherwood Restaurant •Shoot’s Lynwood Tavern •Suburban Bus Terminal •Airway Trailer Park •Oak Lawn Roller Rink •Plenty More! Pictures to the right were taken BEFORE the twister 52 Total Tornadoes in 6 states (5 EF4’s including the Oak Lawn, Belvidere, and Lake Zurich Tornadoes) Oak Lawn Tornado Blue = EF4 Next several slides summary • The next several slides, I will be going through different parameters. -
Wind Enhances Differential Air Advection in Surface Snow at Sub- Meter Scales Stephen A
Wind enhances differential air advection in surface snow at sub- meter scales Stephen A. Drake1, John S. Selker2, Chad W. Higgins2 1College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, 97333, USA 5 2Biological and Ecological Engineering, Oregon State University, Corvallis, 97333, USA Correspondence to: Stephen A. Drake ([email protected]) Abstract. Atmospheric pressure gradients and pressure fluctuations drive within-snow air movement that enhances gas mobility through interstitial pore space. The magnitude of this enhancement in relation to snow microstructure properties cannot be well predicted with current methods. In a set of field experiments we injected a dilute mixture of 1% carbon 10 monoxide and nitrogen gas of known volume into the topmost layer of a snowpack and, using a distributed array of thin film sensors, measured plume evolution as a function of wind forcing. We found enhanced dispersion in the streamwise direction and also along low resistance pathways in the presence of wind. These results suggest that atmospheric constituents contained in snow can be anisotropically mixed depending on the wind environment and snow structure, having implications for surface snow reaction rates and interpretation of firn and ice cores. 15 1 Introduction Atmospheric pressure changes over a broad range of temporal and spatial scales stimulate air movement in near-surface snow pore space (Clarke et al., 1987) that redistribute radiatively and chemically active trace species (Waddington et al., 1996) such as O3 (Albert et al., 2002), OH (Domine and Shepson, 2002) and NO (Pinzer et al., 2010) thereby influencing their reaction rates. Pore space in snow is saturated within a few millimeters of depth in the snowpack that does not have 20 large air spaces (Neumann et al., 2009) so atmospheric pressure changes induce interstitial air movement that enhances snow metamorphism (Calonne et al., 2015; Ebner et al., 2015) and augments vapor exchange between the snowpack and atmosphere. -
A Simple Moisture Advection Model of Specific Humidity
1NOVEMBER 2016 C HADWICK ET AL. 7613 A Simple Moisture Advection Model of Specific Humidity Change over Land in Response to SST Warming ROBIN CHADWICK,PETER GOOD, AND KATE WILLETT Met Office Hadley Centre, Exeter, United Kingdom (Manuscript received 24 March 2016, in final form 25 July 2016) ABSTRACT A simple conceptual model of surface specific humidity change (Dq) over land is described, based on the effect of increased moisture advection from the oceans in response to sea surface temperature (SST) warming. In this model, future q over land is determined by scaling the present-day pattern of land q by the fractional increase in the oceanic moisture source. Simple model estimates agree well with climate model projections of future Dq (mean spatial correlation coefficient 0.87), so Dq over both land and ocean can be viewed primarily as a thermodynamic process controlled by SST warming. Precipitation change (DP) is also affected by Dq, and the new simple model can be included in a decomposition of tropical precipitation change, where it provides increased physical understanding of the processes that drive DP over land. Confidence in the thermodynamic part of extreme precipitation change over land is increased by this improved understanding, and this should scale approximately with Clausius–Clapeyron oceanic q increases under SST warming. Residuals of actual climate model Dq from simple model estimates are often associated with regions of large circulation change, and can be thought of as the ‘‘dynamical’’ part of specific humidity change. The simple model is used to explore intermodel uncertainty in Dq, and there are substantial contributions to uncertainty from both the thermodynamic (simple model) and dynamical (residual) terms. -
OBSERVATIONAL ANALYSIS of the PREDICTABILITY of MESOSCALE CONVECTIVE SYSTEMS by Israel L
National Science Foundation Graduate Fellowship DGE-0234615 and Grant ATM-0324324 OBSERVATIONAL ANALYSIS OF THE PREDICTABILITY OF MESOSCALE CONVECTIVE SYSTEMS by Israel L. Jirak William R. Cotton, P.I. OBSERVATIONAL ANALYSIS OF THE PREDICTABILITY OF MESOSCALE CONVECTIVE SYSTEMS by Israel L. Jirak Department of Atmospheric Science Colorado State University Fort Collins, Colorado 80523 Research Supported by National Science Foundation under a Graduate Fellowship DGE-0234615 and Grant ATM-0324324 October 27, 2006 Atmospheric Science Paper No. 778 ABSTRACT OBSERVATIONAL ANALYSIS OF THE PREDICTABILITY OF MESOSCALE CONVECTIVE SYSTEMS Mesoscale convective systems (MCSs) have a large influence on the weather over the central United States during the warm season by generating essential rainfall and severe weather. To gain insight into the predictability of these systems, the precursor environment of several hundred MCSs were thoroughly studied across the U.S. during the warm seasons of 1996-98. Surface analyses were used to identify triggering mechanisms for each system, and North American Regional Reanalyses (NARR) were used to examine dozens of parameters prior to MCS development. Statistical and composite analyses of these parameters were performed to extract valuable information about the environments in which MCSs form. Similarly, environments that are unable to support organized convective systems were also carefully investigated for comparison with MCS precursor environments. The analysis of these distinct environmental conditions led to the discovery of significant differences between environments that support MCS development and those that do not support convective organization. MCSs were most commonly initiated by frontal boundaries; however, such features that enhance convective initiation are often not sufficient for MCS development, as the environment needs to lend additional support for the development and organization oflong-lived convective systems. -
A Study of Morning Radiation Fog Formation
Air Force Institute of Technology AFIT Scholar Theses and Dissertations Student Graduate Works 3-2000 A Study of Morning Radiation Fog Formation Jimmie L. Trigg Jr. Follow this and additional works at: https://scholar.afit.edu/etd Part of the Meteorology Commons Recommended Citation Trigg, Jimmie L. Jr., "A Study of Morning Radiation Fog Formation" (2000). Theses and Dissertations. 4872. https://scholar.afit.edu/etd/4872 This Thesis is brought to you for free and open access by the Student Graduate Works at AFIT Scholar. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of AFIT Scholar. For more information, please contact [email protected]. A STUDY OF MORNING RADIATION FOG FORMATION THESIS Jimmie L. Trigg, Captain, USAF AFIT/GM/ENP/OOM-14 DEPARTMENT OF THE AIR FORCE rv> AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. rv» DUG QUALITY mmMMM) 4 Acknowledgments I would like to take this opportunity to thank the many people who have helped me in this research and preparation of this thesis. First, I must thank the crew in the weather lab; Pete Rahe, Ed Goetz, Tami Parsons, Liz Boll, Lisa Shoemaker, Mike Holmes and Steve Dickerson. Their help in programming and their understanding during my numerous Tourettes Syndrome like outbreaks made the semester manageable. Next, I would like to thank my thesis advisor Major Gary Huffines. Our numerous conversations and his suggestions gave me the right amount of assistance to focus and concentrate on the subject when I needed it.