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Global Distribution of       L-Band Ionospheric Scintillation                     Xiaoqing Pi                 Anthony J. M...
Outline                                   NASA       • Motivation of the study                 To characterize ionospheri...
Plasma Bubbles and Scintillation Effects                          NASA                     Captured in PolSAR Images      ...
Plasma Bubbles and Scintillation Effects                          NASA                     Captured in PolSAR Images      ...
Plasma Bubbles and Scintillation Effects                          NASA                     Captured in PolSAR Images      ...
Scintillation LT & LAT Distribution                          NASA                    from Ground-Based Measurements       ...
GPS Radio Occultation Tracking                               NASA                                                         ...
Ionospheric Measurements                                          NASA                        from GPS Radio Occultations ...
COSMIC 1-Sec S4 Proxy                                 NASA                for Amplitude Scintillation Measurements        ...
Measured S4 Index and Retrieved Ne Profile                           NASA      F-region                                   ...
F- and E-Region Irregularities/Scintillations                         NASA                                                ...
Ionospheric Scintillation                                 NASA                    Associated with Various Inhomogeneities ...
Data Presentation                                  NASA    • S4,max and its corresponding tangent point altitude (TPALT)  ...
Global Distribution of Amplitude Scintillation                  NASA                   Altitude Range: 150~600 km         ...
Scintillation Occurrence: (2009, LON, LAT)                        NASAJAN                                   FEBMAR        ...
Scintillation Occurrence: (2009, LON, LAT)                        NASAMAY                                   JUNJUL        ...
Scintillation Occurrence: (2009, LON, LAT)                        NASASEP                                  OCTNOV         ...
Scintillation Occurrence: (2009, LT, LAT)                        NASAJAN                                  FEBMAR          ...
Scintillation Occurrence: (2009, LT, LAT)                        NASAMAY                                   JUNJUL         ...
Scintillation Occurrence: (2009, LT, LAT)                        NASASEP                                  OCTNOV          ...
Summary                                         NASA       • Amplitude scintillation measured using GPS radio         occu...
Summary (Cont.)                                     NASA    • The results of the L-band amplitude scintillation      analy...
Copyright Note                                  NASA                             Copyright 2010,                by the Cal...
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  1. 1. Global Distribution of L-Band Ionospheric Scintillation Xiaoqing Pi Anthony J. Mannucci Anthony FreemanJet Propulsion Laboratory, California Institute of Technology IGARSS, Vancouver, Canada, July 26, 2011
  2. 2. Outline NASA • Motivation of the study  To characterize ionospheric scintillation using GPS data made with GPS radio occultation receivers onboard six COSMIC satellites  To provide statistics of global ionospheric scintillation to support spaceborne remote sensing radar mission planning and data analyses • Statistical Analysis  COSMIC 1-sec S4 measurements (amplitude scintillation)  Global measurements made from all COSMIC satellites in 12 months  LAT, LON, LT, and ALT distribution; F and E regions • SummaryJuly 26, 2011 Global Distribution of Ionospheric Scintillation 2
  3. 3. Plasma Bubbles and Scintillation Effects NASA Captured in PolSAR Images Polarimetric observations made using ALOS PALSAR reveal • random fluctuations of polarization (Faraday rotation) • depletion of Faraday rotation (or TEC) [Pi et al., 2011, JGR]September 21, 2009 Pi et al.: Ionospheric Variations Imaged Using GPS & SAR 3
  4. 4. Plasma Bubbles and Scintillation Effects NASA Captured in PolSAR Images Polarimetric observations made using ALOS PALSAR reveal • random fluctuations of polarization (Faraday rotation) • depletion of Faraday rotation (or TEC) [Pi et al., 2011, JGR]September 21, 2009 Pi et al.: Ionospheric Variations Imaged Using GPS & SAR 4
  5. 5. Plasma Bubbles and Scintillation Effects NASA Captured in PolSAR Images Polarimetric observations made using ALOS PALSAR reveal • random fluctuations of polarization (Faraday rotation) • depletion of Faraday rotation (or TEC) [Pi et al., 2011, JGR]September 21, 2009 Pi et al.: Ionospheric Variations Imaged Using GPS & SAR 5
  6. 6. Scintillation LT & LAT Distribution NASA from Ground-Based Measurements [Basu, 2003]December 19, 2008 Pi et al.: Imaging the Ionosphere Using SAR & GPS 6
  7. 7. GPS Radio Occultation Tracking NASA LEO GPS [wikipedia.com]July 26, 2011 Global Distribution of Ionospheric Scintillation 7
  8. 8. Ionospheric Measurements NASA from GPS Radio Occultations Density Profiles • Time sequence of dual-frequency GPS phase and pseudorange measurements to derive TEC along the signal path • Abel inversion  electron and neutral density profile Scintillation • 50-Hz L1 C/A SNR data • 1-sec amplitude scintillation S4 proxy • Time sequence of S4  S4 alt profile • S4,max for the profileJuly 26, 2011 Global Distribution of Ionospheric Scintillation 8
  9. 9. COSMIC 1-Sec S4 Proxy NASA for Amplitude Scintillation Measurements • 1-second S4 index proxy, is the low-pass filtered intensity, and the filtering is performed on . The average is approximately derived from the SNR data. • SNR: L1-C/A signal to noise ratio, sampled at 50 Hz • No phase scintillation measurements (which require higher standard and more expensive oscillator as well as more CPU, storage, and power)July 26, 2011 Global Distribution of Ionospheric Scintillation 9
  10. 10. Measured S4 Index and Retrieved Ne Profile NASA F-region Weak topside Scintillation Irregularities (?) or noisy ? data Nighttime Duration:   9.7 min E Layer TP range:  ~ 10.7° Max S4  ~ 4.7° • LEO: CSM02 • LAT: –42.519° • GPS: PRN11 • LON: 168.043°July 26, 2011 Global Distribution of Ionospheric Scintillation 10
  11. 11. F- and E-Region Irregularities/Scintillations NASA EveningF-RegionIrregularities F-Region and E-Region Scintillation E Layer • LEO: CSM04 • LAT: –4.086° • GPS: PRN19 • LON: 37.336°July 26, 2011 Global Distribution of Ionospheric Scintillation 11
  12. 12. Ionospheric Scintillation NASA Associated with Various Inhomogeneities Topside Irregularities F-region Irregularities E-Region Layering, etc. • LEO’s: CSM01-06 • 2009.274 (one day in Oct) • GPS’s: All • Global, all timeJuly 26, 2011 Global Distribution of Ionospheric Scintillation 12
  13. 13. Data Presentation NASA • S4,max and its corresponding tangent point altitude (TPALT)  Radio occultation links: elevation angle ≤ 0°  Tangent point: the point along the radio link where the distance to the center of the Earth is closest  Maximum S4 in an occultation profile  TPALT: altitude of the tangent point • Data binning • Median(S4,max) • ALT range  150 – 600 km (F region)  80 – 150 km (D and E region) • Occurrence Rate  N_Events(S4,max >= S4,max0) / N_Total_SamplesJuly 26, 2011 Global Distribution of Ionospheric Scintillation 13
  14. 14. Global Distribution of Amplitude Scintillation NASA Altitude Range: 150~600 km October 2009LAT S4 LONLAT S4 LTJuly 26, 2011 Global Distribution of Ionospheric Scintillation 14
  15. 15. Scintillation Occurrence: (2009, LON, LAT) NASAJAN FEBMAR APRJuly 26, 2011 Global Distribution of Ionospheric Scintillation 15
  16. 16. Scintillation Occurrence: (2009, LON, LAT) NASAMAY JUNJUL AUGJuly 26, 2011 Global Distribution of Ionospheric Scintillation 16
  17. 17. Scintillation Occurrence: (2009, LON, LAT) NASASEP OCTNOV DECJuly 26, 2011 Global Distribution of Ionospheric Scintillation 17
  18. 18. Scintillation Occurrence: (2009, LT, LAT) NASAJAN FEBMAR APRJuly 26, 2011 Global Distribution of Ionospheric Scintillation 18
  19. 19. Scintillation Occurrence: (2009, LT, LAT) NASAMAY JUNJUL AUGJuly 26, 2011 Global Distribution of Ionospheric Scintillation 19
  20. 20. Scintillation Occurrence: (2009, LT, LAT) NASASEP OCTNOV DECJuly 26, 2011 Global Distribution of Ionospheric Scintillation 20
  21. 21. Summary NASA • Amplitude scintillation measured using GPS radio occultation signals must be characterized according to altitude regions (F and E regions) where different ionospheric phenomena occur  F-region ionospheric irregularities, which also cause scintillation in ground-based GPS observations  E-region density changes or layering in a narrow altitude range, which usually do not cause scintillation in ground-based GPS or spaceborne observationsJuly 26, 2011 Global Distribution of Ionospheric Scintillation 21
  22. 22. Summary (Cont.) NASA • The results of the L-band amplitude scintillation analysis  Distinguished local time, longitudinal, and seasonal variations at low latitudes – Equinox months: extending to most longitudes – May through August: Pacific regions – Dec through Feb: America longitudes – Nighttime phenomenon: after sunset, through 3 or 4 AM  Insignificant amplitude scintillation in high latitude/Auroral regions – Dec 2009: an exception; daytime scintillation is observed in the southern hemisphere  Note (based on previous studies using ground-based GPS data): – Phase scintillation cannot be ignored at high latitudes, which is not analyzed here – Phase scintillation is usually as strong as amplitude at low latitudes, and stronger than amplitude scintillation at high latitudesJuly 26, 2011 Global Distribution of Ionospheric Scintillation 22
  23. 23. Copyright Note NASA Copyright 2010, by the California Institute of Technology. All RIGHTS RESERVED. United States Government Sponsorship acknowledged.July 26, 2011 Global Distribution of Ionospheric Scintillation 23
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