DOCSLIB.ORG

Seasonal and Local Solar Time Variation of the Meridional Wind at 95 Km from Observations of the 11.072-Ghz Ozone Line and the 557.7-Nm Oxygen Line

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Seasonal and Local Solar Time Variation of the Meridional Wind at 95 Km from Observations of the 11.072-Ghz Ozone Line and the 557.7-Nm Oxygen Line Seasonal and Local Solar Time Variation of the Meridional Wind at 95 km from Observations of the 11.072-GHz Ozone Line and the 557.7-nm Oxygen Line The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Rogers, Alan E. E. et al. “Seasonal and Local Solar Time Variation of the Meridional Wind at 95 Km from Observations of the 11.072-GHz Ozone Line and the 557.7-Nm Oxygen Line.” Journal of Atmospheric and Oceanic Technology 33.7 (2016): 1355–1361. © 2016 American Meteorological Society As Published http://dx.doi.org/10.1175/jtech-d-15-0247.1 Publisher American Meteorological Society Version Final published version Citable link http://hdl.handle.net/1721.1/107662 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. JULY 2016 R O G E R S E T A L . 1355 Seasonal and Local Solar Time Variation of the Meridional Wind at 95km from Observations of the 11.072-GHz Ozone Line and the 557.7-nm Oxygen Line ALAN E. E. ROGERS,PHILIP J. ERICKSON, AND LARISA P. GONCHARENKO Haystack Observatory, Massachusetts Institute of Technology, Westford, Massachusetts OMAR B. ALAM School of Applied and Engineering Physics, Cornell University, Ithaca, New York a JOHN NOTO,ROBERT B. KERR, AND SUDHA KAPALI Scientific Solutions, Inc., North Chelmsford, Massachusetts (Manuscript received 8 December 2015, in final form 31 March 2016) ABSTRACT Ground-based spectrometers have been deployed to measure the concentration, velocity, and temperature of ozone in the mesosphere and lower thermosphere (MLT), using low-cost satellite television electronics to observe the 11.072-GHz line of ozone. The ozone line was observed at an altitude near 95 km at 388N, 718W using three spectrometers located at the Massachusetts Institute of Technology’s Haystack Observatory (Westford, Massa- chusetts), Chelmsford High School (Chelmsford, Massachusetts), and Union College (Schenectady, New York), each pointed south at 88 elevation. Observations from 2009 through 2014 were used to derive the nightly averaged seasonal variation of the 95-km altitude meridional wind velocity, as well as the seasonally averaged variation of the meridional wind with local solar time. The results indicate a seasonal trend in which the winds at 95 km are directed 2 2 southward at about 10 m s 1 in the summer of the Northern Hemisphere and northward at about 10 m s 1 in the winter. Nighttime data from 25to15 local solar time show a gradual transition of the meridional wind velocity 2 from about 220 to 20 m s 1. These variations correlate well with nighttime wind measurements using 557.7-nm optical airglow observations from the Millstone Hill high-resolution Fábry–Perot interferometer (FPI) in Westford. 1. Introduction goal of providing locally acquired data to aid in the teaching of data analysis methods and statistics to high school stu- The Mesospheric Ozone System for Atmospheric In- dents, MOSAIC provides an ongoing source of science- vestigations in the Classroom (MOSAIC) is an educational quality data on mesospheric ozone variations, and the data project focused on ground-based observations of the rela- are publicly available online.1 The ozone in the upper me- tively weak microwave line of ozone at 11.072 454 5 GHz sosphere is measured by MOSAIC using a satellite TV low- (Pickett et al. 1998) in the upper mesosphere using low-cost noise block downconverter, followed by an intermediate satellite television (TV) electronics. Along with its primary frequency downconverter and analog-to-digital converter. To increase the strength of the line, the antenna beam is pointed an elevation of 88 to increase the pathlength Denotes Open Access content. through the atmosphere. The ozone in the upper meso- sphere is at low pressure, so a narrow Doppler broadened line originating from an altitude of about 95 km stands out a Current affiliation: Scientific Computing, Inc., Springfield, Virginia. Corresponding author address: Alan E. E. Rogers, Haystack 1 MOSAIC data are archived in the Madrigal distributed data- Observatory, Massachusetts Institute of Technology, Off Route 40, base system, supported by the U.S. National Science Foundation’s Westford, MA 01886-1299. Atmospheric and Geospace Sciences directorate for atmospheric E-mail: [email protected] studies (http://madrigal.haystack.mit.edu/). DOI: 10.1175/JTECH-D-15-0247.1 Ó 2016 American Meteorological Society 1356 JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY VOLUME 33 from the pressure-broadened line from the ozone at lower altitudes. In this paper we assume a nominal altitude for the secondary maximum of the nighttime ozone to be 95 km (Smith and Marsh 2005). We also assume based on satellite measurements (Gao et al. 2012) that the 557.7-nm oxygen line originates from the same altitude. A complete de- scription of the instrument and measurements of the sea- sonal and diurnal variations of ozone near the mesopause for data collected in 2008 were reported by Rogers et al. (2009). The repeatability of seasonal mesospheric ozone variations from 2008 through 2011 at six sites in the north- eastern United States was reported by Rogers et al. (2012). While the observed line is only about 20 mK out of a background system noise of about 100 K, it is never- theless possible to estimate the average velocity of the ozone from the small shift in the line center frequency due to the Doppler shift from the wind at 95 km. In this paper, we report the average nighttime mesospheric wind from three spectrometers located at the Massachusetts Institute of Technology (MIT)’s Haystack Observatory (Westford, Massachusetts), Chelmsford High School (Chelmsford, Massachusetts), and Union College (Sche- nectady, New York) using data from 2010 through 2014. These sites have their antenna beams pointing south, al- FIG. 1. Seasonal trend in the average velocity of ozone at night. The error bars are 61s. lowing the measurement of the meridional wind at a latitude of 388N and a longitude around 718W, where the antenna beams intersect the region at 95 km. velocity data during nighttime only (Rogers et al. 2009). Daytime data are not available due to the an- nihilation of most of the ozone at 95 km by ultraviolet 2. Instrumentation photons from the sun. This reduces the opacity by a The velocity data were acquired from a network of factor of about 10 (Smith and Marsh 2005) and reduces three ozone spectrometers located at the MIT Hay- the signal to a few millikelvins, resulting in an in- stack Observatory (42.6188N, 71.4988W), Union Col- sufficient signal-to-noise ratio (SNR). lege (42.8178N, 73.9288W), and Chelmsford High Information on the temperature of the ozone in the School (42.6198N, 71.3678W). The spectrometers are mesosphere and lower thermosphere (MLT) can be pointed at azimuths 1908,1808, and 1728, respectively. obtained from the line shape near the peak, where the The beam of each spectrometer physically intersects width is determined primarily from the Doppler the ozone layer at 95 km at 388N, 718W, which is in the broadening of the ozone above about 90 km. However, Atlantic Ocean about 200 km off the coast of Maryland. the results we report in this paper are obtained from Data at Haystack were taken from 24 January 2009 single-channel spectrometers for which the SNR is in- through 13 August 2014. Data at Union College were sufficient to obtain measurements of temperature with taken from 19 February 2009 through 8 June 2015. Fi- integration times of less than several weeks. In the fu- nally, data at Chelmsford High School were taken from ture, following the spectrometer enhancements, which 25 December 2011 through 8 June 2015. The three will be discussed in section 6, we may be able to obtain spectrometers use temperature-controlled oven crystal temperatures on time scales of geophysical relevance. oscillators at 10 MHz as a frequency reference. Tests were made of the accuracy of the reference by 3. Results injecting a test signal at 11.072 454 5 GHz from a syn- thesizer whose reference had been checked against an Figures 1 and 2 show velocity data from the MOSAIC atomic clock. The accuracy of the frequency control of spectrometers at Haystack, Union, and Chelmsford. By the ozone spectrometers was estimated to be within 7 convention, negative velocities denote winds directed parts in 109, corresponding to a line-of-sight velocity southward (northerly wind), and positive velocities de- 2 accuracy of 2 m s 1. Ozone spectrometers collect wind note winds directed northward (southerly wind). To JULY 2016 R O G E R S E T A L . 1357 significant given the large instrumental noise in the ozone data, it could be related to a longer time coverage by the Haystack spectrometer (2009–15) that includes a period of very low solar activity and potential de- pendence of MLT winds on solar activity or quasi- biennial oscillation (Forbes et al. 2008; Oberheide et al. 2009). In addition, a frequency error could be re- sponsible. The Haystack spectrometer electronics is the only one of the network’s three spectrometers whose data are used in this paper that is located in an unheated building. The new spectrometers will be equipped with a stable frequency reference as will be discussed in section 6. Figure 2 reveals significant local time variation, in that there are southward winds from 25 through 11 h local solar time, and northward winds from 12 through 15h. The transition point appears to be within 2 h after mid- night, and the full transition is from about 220 2 to 125 m s 1 in amplitude.
Load more

Recommended publications
  • A Very Bright SAR Arc: Implications for Extreme Magnetosphere-Ionosphere Coupling J
    A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling J. Baumgardner, J. Wroten, J. Semeter, J. Kozyra, M. Buonsanto, P. Erickson, M. Mendillo To cite this version: J. Baumgardner, J. Wroten, J. Semeter, J. Kozyra, M. Buonsanto, et al.. A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling. Annales Geophysicae, European Geo- sciences Union, 2008, 25 (12), pp.2593-2608. <hal-00318424> HAL Id: hal-00318424 https://hal.archives-ouvertes.fr/hal-00318424 Submitted on 2 Jan 2008 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. Ann. Geophys., 25, 2593–2608, 2007 www.ann-geophys.net/25/2593/2007/ Annales © European Geosciences Union 2007 Geophysicae A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling J. Baumgardner1, J. Wroten1, J. Semeter1, J. Kozyra2, M. Buonsanto3, P. Erickson3, and M. Mendillo1 1Center for Space Physics, Boston University, Boston, MA, USA 2Department of Atmospheric, Oceanic and Space Science, University of Michigan, Ann Arbor, MI, USA 3MIT Haystack Observatory, Westford, MA, USA Received: 8 August 2007 – Revised: 3 September 2007 – Accepted: 25 October 2007 – Published: 2 January 2008 Abstract. In contrast to the polar aurora visible during geo- 1 Introduction magnetic storms, stable auroral red (SAR) arcs offer a sub- visual manifestation of direct magnetosphere-ionosphere Extreme events in the solar-terrestrial system offer rare op- (M-I) coupling at midlatitudes.
    [Show full text]
  • Incoherent Scatter Radar Observation at Millstone Hill
    Ionospheric longitudinal variations at midlatitudes: Incoherent scatter radar observation at Millstone Hill The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Zhang, ShunRong et al. “Ionospheric Longitudinal Variations at Midlatitudes: Incoherent Scatter Radar Observation at Millstone Hill.” Science China Technological Sciences 55.5 (2012): 1153–1160. As Published http://dx.doi.org/10.1007/s11431-012-4784-y Publisher SP Science China Press Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/104911 SCIENCE CHINA Technological Sciences May 2012 Vol.55 No.5: 1153–1160 doi: 10.1007/s11431-012-4784-y Ionospheric longitudinal variations at midlatitudes: Incoherent scatter radar observation at Millstone Hill ZHANG ShunRong*, COSTER Anthea, HOLT John, FOSTER John & ERICKSON Phil MIT Haystack Observatory, Off Route 40, Westford, MA 01866, USA Received January 2, 2012; accepted February 9, 2012; published online March 26, 2012 Incoherent scatter radar (ISR) extra-wide coverage experiments during the period of 1978–2011 at Millstone Hill are used to investigate longitudinal differences in electron density. This work is motivated by a recent finding of the US east-west coast difference in TEC suggesting a combined effect of changing geomagnetic declination and zonal winds. The current study pro- vides strong supporting evidence of the longitudinal change and the plausible mechanism by examining the climatology of electron density Ne on both east and west sides of the radar with a longitude separation of up to 40o for different heights within 300–450 km. Main findings include: 1) The east-west difference can be up to 60% and varies over the course of the day, being positive (East side Ne > West side Ne) in the late evening, and negative (West side Ne > East side Ne) in the pre-noon.
    [Show full text]
  • The CEDAR Post
    The CEDAR Post August 1998 Volume 34 FROM THE STEERING COMMITTEE The June 1998 CEDAR meeting was another productive and successful forum for interactions by our community. This issue of the Post presents summaries ofthe meeting highlights and the workshops convened at the meeting. A new membership list of the CEDAR Science Steering IN THIS ISSUE Committee (CSSC) for 1998-1999 is given on page 2. From the Steering Committee 1 Cassandra Fesen (University of Texas at Dallas) was CEDAR Science Steering Committee for 1998-99 2 Status of the Polar Cap Observatory 3 appointed to the committee and will chair it starting at the K. Baker: New NSF Program Director 4 end of the next CEDAR meeting in June 1999. Jean-Pierre CEDAR's Huailin Chen wins OSA's Allen Prize 4 CEDAR Post-doctoral Fellowships for 1998-2000 4 St. Maurice (University of Western Ontario, Canada) will be NSF Grant Awards from FY 1998 CEDAR Competition 5 one of the two international representatives on the CSSC. Summary Report: 1998 CEDAR Meeting 6 Roger Smith (University of Alaska) has been appointed to Workshop Reports'. serve as a liaison with the GEM community and will also ISR World Day Schedule for 1999 7 serve on the GEM Steering Committee. Andrew Stephan Communicating with One's Peers 7 I.idar: Overview, Progress and Updates 8 (Boston University) will be the student representative for Upper Atmosphere Facilities/IS Radars 9 1998-1999. We thank Michael Mendillo, Gordon Shepherd Wide Latitude Substorm (WLS) Study 9 and Julie Chang who completed their terms on the CSSC in CEDAR Storm Study 10 Synthesizing High-latitude IonosphericElectrodynamics 11 June 1998.
    [Show full text]
  • Thermospheric Poleward Wind Surge at Midlatitudes During Great Storm Intervals
    Thermospheric poleward wind surge at midlatitudes during great storm intervals The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Zhang, Shun-Rong, Philip J. Erickson, John C. Foster, John M. Holt, Anthea J. Coster, Jonathan J. Makela, John Noto, et al. “Thermospheric Poleward Wind Surge at Midlatitudes during Great Storm Intervals.” Geophysical Research Letters 42, no. 13 (July 16, 2015): 5132–40. As Published http://dx.doi.org/10.1002/2015GL064836 Publisher American Geophysical Union (AGU) Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/98250 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. 1 Thermospheric Poleward Wind Surge at Mid-Latitudes During Great 2 Storm Intervals 3 4 Shun-Rong Zhang1,*, Philip J. Erickson1, John C. Foster1, John M. Holt1, Anthea J. 5 Coster1, Jonathan J. Makela2, John Noto3, John W. Meriwether4, Brian J. Harding2, 6 Juanita Riccobono3 and Robert B. Kerr3 7 8 1 MIT Haystack Observatory, Westford, MA, USA 9 2 Department of Electrical and Computer Engineering, University of Illinois at 10 Urbana-Champaign, Urbana, Illinois, USA 11 3 Scientific Solution, Inc., Chelmsford, MA, USA 12 4 Department of Physics and Astronomy, Clemson University, Clemson, SC, USA 13 14 * Correspondence: 15 Dr. Shunrong Zhang ([email protected]) 16 MIT Haystack Observatory 17 Off Route 40 18 Westford, MA 01886 19 USA 20 21 Key points 22 1.
    [Show full text]
  • A Workstation-Based Incoherent Scatter Radar Data Acquisition System J
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by HAL-INSU MIDAS-W: a workstation-based incoherent scatter radar data acquisition system J. M. Holt, P. J. Erickson, A. M. Gorczyca, T. Grydeland To cite this version: J. M. Holt, P. J. Erickson, A. M. Gorczyca, T. Grydeland. MIDAS-W: a workstation-based incoherent scatter radar data acquisition system. Annales Geophysicae, European Geosciences Union, 2000, 18 (9), pp.1231-1241. <hal-00316793> HAL Id: hal-00316793 https://hal.archives-ouvertes.fr/hal-00316793 Submitted on 1 Jan 2000 HAL is a multi-disciplinary open access L'archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destin´eeau d´ep^otet `ala diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publi´esou non, lished or not. The documents may come from ´emanant des ´etablissements d'enseignement et de teaching and research institutions in France or recherche fran¸caisou ´etrangers,des laboratoires abroad, or from public or private research centers. publics ou priv´es. Ann. Geophysicae 18, 1231±1241 /2000) Ó EGS ± Springer-Verlag 2000 MIDAS-W: a workstation-based incoherent scatter radar data acquisition system J. M. Holt1, P. J. Erickson1, A. M. Gorczyca1, T. Grydeland2 1 Massachusetts Institute of Technology, Haystack Observatory, Westford, MA 01886, USA 2 University of Tromsù, Tromsù, Norway Received: 28 December 1999 / Revised: 19 June 2000 / Accepted: 21 June 2000 Abstract. The Millstone Hill Incoherent Scatter Data simpli®ed, because a workstation with the new software Acquisition System /MIDAS) is based on an abstract can be added to the network without impacting the model of an incoherent scatter radar.
    [Show full text]
  • Comparison of Simultaneous Chatanika and Millstone Hill Observations with Ionospheric Model Predictions
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 91, NO. A6, PAGES 6986-6998, JUNE 1, 1986 Comparison of Simultaneous Chatanika and Millstone Hill Observations With Ionospheric Model Predictions c. E. RASMUSSEN,' R. W. SCHUNK,' J. J. SOJKA,' v. B. WICKWAR,2 O. DE LA BEAUJARDIERE,2 J. FOSTER,) J. HOLT,) D. S. EVANS,4 AND E. NIELSEN S As part of the MITHRAS program, the Chatanika and Millstone Hill incoherent-scatter radars ma.de coordinated observations of the polar ionosphere on June 27 and 28, 1981. We compare the.se da~a with predictions made by a high-latitude ionospheric mo~el. Qualitative.ly, th~ same ~eatu~es are eVident In b?th the model and the radar data: fairly constant densities on the dayslde with a mid-latitude trough formmg poleward of65 degrees around 1900 ML T (magneti~ ~ocal time~. T~is trough is seen toe~tend equat?r~ard with increasing MLT, such that the minimum densities occurnng m the tro~gh appear J~st after ml~nlght around 60 degrees dipole latitude. These features are primari~y understood In terms of different re~lOns .of convection, further influenced by photoionization and vertical transport. The only area~ of major. diS- agreement between the measurements and model are noted in the auroral ov~l and ~t a portion of the times during which substorms occurred. Quantitatively, equally good agreement IS obtamed . be~ween the model predictions and the radar data. The densities. predicted by t~e model a~e usually :-Vlthm 25% of tho~e measured by the radars, alth ough appreciable differences occur In some regions of the IOnosphere at certam times.
    [Show full text]
  • Comparison of the First Long-Duration IS Experiment Measurements Over
    Advances in Space Research 37 (2006) 1102–1107 www.elsevier.com/locate/asr Comparison of the first long-duration IS experiment measurements over Millstone Hill and EISCAT Svalbard radar with IRI2001 Jiuhou Lei a,b,c,*, Libo Liu a, Weixing Wan a, Shun-Rong Zhang d, A.P. Van Eyken e a Institute of Geology and Geophysics, CAS, Beijing 100029, P.R. China b Wuhan Institute of Physics and Mathematics, CAS, Wuhan 430071, P.R. China c Graduate School of the Chinese Academy of Sciences, P.R. China d Haystack Observatory, Massachusetts Institute of Technology, Westford, Massachusetts, USA e EISCAT Scientific Association, Headquarters, Kiruna, Sweden Received 10 August 2004; received in revised form 25 January 2005; accepted 26 January 2005 Abstract The first long-duration incoherent scatter (IS) radar observations over Millstone Hill (42.6°N, 288.5°E) and EISCAT Svalbard radar (ESR, 78.15°N, 16.05°E) from October 4 to November 4, 2002 are compared with the newly updated version of the IRI model (IRI2001). The present study showed that: (1) For the peak parameters hmF2 and foF2, the IRI results are in good agreement with the observations over Millstone Hill, but there are large discrepancies over ESR. For the B parameters, the table option of IRI pro- duces closer values to the observed ones with respect to the GulyaevaÕs option. (2) When the observed F2 peak parameters are used as input of IRI, the IRI model produces the reasonably results for the bottomside profiles during daytime over Millstone Hill, while it gives a lower bottomside density during nighttime over Millstone Hill and the whole day over ESR than what is observed exper- imentally.
    [Show full text]
  • Boston University Center for Space Physics
    2011-2012 Annual Report Boston University Center for Space Physics Director: John Clarke 1 Associate Director: Josh Semeter Table of Contents Executive Summary ................................................................................................................................................................. 1 Overview ............................................................................................................................................................................. 1 Highlights ............................................................................................................................................................................ 1 CSP Operations ........................................................................................................................................................................ 2 Selected Research Highlights .................................................................................................................................................. 3 PICTURE: The Search for Extra‐solar Planets ...................................................................................................................... 3 Preparing for the Mars Science Lander ............................................................................................................................... 3 Detecting Aurora on Uranus ..............................................................................................................................................
    [Show full text]
  • MIT Haystack & Millstone Hill Observatories & Lincoln Space
    MASSACHUSETTS INSTITUTE OF TECHNOLOGY HAYSTACK OBSERVATORY MILLSTONE HILL OBSERVATORY LINCOLN SPACE SURVEILLANCE COMPLEX 1 NORTHEAST RADIO OBSERVATORY CORPORATION MIT LINCOLN LABORATORY CONTENTS Page General Information ........................................................ 2 Introduction .................................................................... 3 Haystack Observatory...................................................... 4 Very Long Baseline Interferometry (VLBI) ...................... 8 Millstone Hill Observatory ............................................ 15 Lincoln Space Surveillance Complex ............................. 21 Educational Role and Contributions ............................. 26 Infrastructure and Other Facilities ................................. 31 GENERAL INFORMATION General information about the research facilities and programs at the Observatory and its parent organizations are available on the World Wide Web at the following addresses: Haystack Observatory http://www.haystack.edu/haystack Millstone Hill Observatory http://www.haystack.edu Lincoln Laboratory http://www.ll.mit.edu Massachusetts Institute of Technology http://web.mit.edu 2 INTRODUCTION Nestled among the hilly woods of Westford, Tyngsboro, and Groton, Massachusetts, and surrounded by some of the nation’s most prestigious universities and research centers, an array of large radio, radar, and optical instruments are used by scientists and engineers from the Massachusetts Institute of Technology (MIT), the Northeast Radio Observatory Corporation
    [Show full text]
  • A Statistical Study of Ionospheric Profile Parameters Derived From
    GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L14804, doi:10.1029/2004GL020578, 2004 A statistical study of ionospheric profile parameters derived from Millstone Hill incoherent scatter radar measurements Jiuhou Lei,1,2,3 Libo Liu,1 Weixing Wan,1 Shun-Rong Zhang,4 and John M. Holt4 Received 22 May 2004; revised 14 June 2004; accepted 18 June 2004; published 24 July 2004. [1] Diurnal, seasonal, and solar activity variations of the 1990] took the constant value of 3. Comparisons with bottomside electron density profile parameters B0 and B1, observations revealed large discrepancies in the bottomside representing the F2 layer thickness and shape, are studied density at various stations [e.g., Zhang et al., 1996; Sethi and using a large incoherent scatter radar dataset for Millstone Pandey, 2001, and references therein], therefore there were Hill covering the period 1976–2002. These results are various attempts to develop a new model for B0and compared with the latest IRI model. Our statistical study is B1[Huang and Reinisch, 1997; Adeniyi and Radicella, characterized by morning and afternoon falls in the diurnal 1998; Mahajan and Sethi, 2001; Sethi et al., 2000; Zhang et variation of B0 for seasons other than summer and a 15% al., 2000] through a series of IRI task force activities change in B1 over a solar cycle, features not fully well [Radicella, 2001]. Some of the results from these efforts represented by the standard IRI model. The standard IRI B1, have now been included in the newest IRI model, IRI-2001. however, is very close to observations in terms of the In this model, B0 tables were obtained from more iono- diurnal variation.
    [Show full text]
  • Validation and Characterization of Ionospheric Densities Measured by DMSP
    Air Force Institute of Technology AFIT Scholar Theses and Dissertations Student Graduate Works 3-2001 Validation and Characterization of Ionospheric Densities Measured by DMSP Herbert L. Keyser Follow this and additional works at: https://scholar.afit.edu/etd Part of the Atmospheric Sciences Commons Recommended Citation Keyser, Herbert L., "Validation and Characterization of Ionospheric Densities Measured by DMSP" (2001). Theses and Dissertations. 4643. https://scholar.afit.edu/etd/4643 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]. VALIDATION AND CHARACTERIZATION OF IONOSPHERIC DENSITIES MEASURED BY DMSP THESIS Herbert L. Keyser, Captain, USAF AFIT/GAP/ENP/01M-05 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. The views expressed in this thesis are those of the author and do not reflect the official policy or position of the United States Air Force, Department of Defense, or the U. S. Government. AFIT/GAP/ENP/OlM-05 VALIDATION AND CHARACTERIZATION OF IONOSPHERIC DENSITIES MEASURED BY DMSP THESIS Presented to the Faculty Department of Engineering Physics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In Partial Fulfillment of the Requirements for the Degree of Master of Science in Applied Physics Herbert L. Keyser, B.S. Captain, USAF March 2001 APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED.
    [Show full text]
  • The Advanced Modular Incoherent Scatter Radar (AMISR) Historical Perspectives
    The Advanced Modular Incoherent Scatter Radar (AMISR) Historical Perspectives Bob Robinson National Science Foundation Earth’s Atmosphere The Ionosphere/Thermosphere/Mesosphere Space Weather Effects Incoherent Scatter Radars: The most direct technique for routinely observing fundamental properties of the ionosphere and upper atmosphere. Ionosphere The weak return signals from high-power radio transmitters are used to deduce properties of the ionosphere Ionospheric Electron Electron Ion Drift Collision and Ion Density Velocity Frequencies Composition Temps. The History of Incoherent Scatter 1955 in a Nutshell 1960 The Era of Construction for U. S. Incoherent Scatter Radars 1965 1970 The National Science Foundation takes over 1975 1980 The Era of Construction for European 1985 Incoherent Scatter Radars 1990 1995 2000 The Age of AMISR 2005 2010 1958-1959 Bill Gordon conceives of the idea of incoherent scatter and construction begins at Arecibo, Puerto Rico, with funding from the Defense Advanced Research Project Office (DARPA) 1961 The Jicamarca Observatory is constructed near Lima, Peru, by the National Bureau of Standards. 1962 Construction of Arecibo is completed. 1963 The Millstone Hill zenith antenna is constructed by MIT Lincoln Laboratories at a site near Boston, MA 1971 The Chatanika Radar is moved from Stanford University to a new site near Fairbanks, Alaska. 1982 The Chatanika Radar is moved to a new location near Sondrestrom, Greenland, The NSF Incoherent1970 Scatter – 1980 Radar Chain-2006Chain-2007 The U. S. National Science Foundation takes over operation of four incoherent scatter radars PFR Sondrestrom (SRF) 2007 SRF 1982 1982 AMISR- Sondrestrom Poker Flat MH 1962 AO 1962 MillstoneMillstone Hill Hill(MH) JRO Jicamarca (JRO) JRO 1963 Jicamarca AreciboArecibo (AO) 1981 The European conquest begins with the construction of the EISCAT UHF system at Tromso, Norway.
    [Show full text]