Atmospheric radio occultation relies on the detection of a change in a radio signal as it passes through a planet's atmosphere, i.e. as it is occulted by the atmosphere. When electromagnetic radiation passes through the atmosphere, it is refracted (or bent). The magnitude of the refraction depends on the gradient of refractivity normal to the path, which in turn depends on the density gradient. The effect is most pronounced when the radiation traverses a long atmospheric limb path. At radio frequencies the amount of bending cannot be measured directly; instead, the bending can be calculated using the Doppler shift of the signal given the geometry of the emitter and receiver. The amount of bending can be related to the refractive index by using an Abel transform on the formula relating bending angle to refractivity. In the case of the neutral atmosphere (below the ionosphere) information on the atmosphere's temperature, pressure and water vapor content can be derived by giving radio occultation data applications in meteorology.[1]
GNSS radio occultationedit
GNSS radio occultation (GNSS-RO), historically also known as GPS radio occultation (GPS-RO or GPSRO), is a type of radio occultation that relies on radio transmissions from GPS (Global Positioning System), or more generally from GNSS (Global Navigation Satellite System), satellites.[2][3] This is a relatively new technique (first applied in 1995) for performing atmospheric measurements. It is used as a weather forecasting tool, and could also be harnessed in monitoring climate change. The technique involves a low-Earth-orbit satellite receiving a signal from a GPS satellite. The signal has to pass through the atmosphere and gets refracted along the way. The magnitude of the refraction depends on the temperature and water vapor concentration in the atmosphere.[4]
GNSS radio occultation amounts to an almost instantaneous depiction of the atmospheric state. The relative position between the GPS satellite and the low-Earth-orbit satellite changes over time, allowing for a vertical scanning of successive layers of the atmosphere.[5]
GPSRO observations can also be conducted from aircraft[6] or on high mountaintops.[7]
^ abDing, Tong; Awange, Joseph L.; Scherllin‐Pirscher, Barbara; Kuhn, Michael; Anyah, Richard; Zerihun, Ayalsew; Bui, Luyen K. (16 September 2022). "GNSS Radio Occultation Infilling of the African Radiosonde Data Gaps Reveals Drivers of Tropopause Climate Variability". Journal of Geophysical Research: Atmospheres. 127 (17). Bibcode:2022JGRD..12736648D. doi:10.1029/2022JD036648. hdl:20.500.11937/91903. S2CID 251652497.
^Melbourne et al. 1994. The application of spacebourne GPS to atmospheric limb sounding and global change monitoring. Publication 94-18, Jet Propulsion Laboratory
^Kursinski et al. 1997. Observing the Earth's atmosphere with radio occultation measurements using the Global Positioning System. J. Geophys. Res. 102:23.429-23.465.
^"GPS 'thermometer' could flag up climate change". Retrieved 2008-02-16.
^. Archived from the original on 2009-05-15. Retrieved 2008-02-16.
^Xie, F.; Haase, J. S.; Syndergaard, S. (2008). "Profiling the atmosphere using the airborne GPS occultation technique: A sensitivity study". IEEE Transactions on Geoscience and Remote Sensing. 46 (11). doi:10.1109/TGRS.2008.2004713. S2CID 23345728.
^Zuffada, C.; Hajj, G. A.; Kursinski, E. R. (1999). "A novel approach to atmospheric profiling with a mountain-based or airborne GPS receiver" (PDF). Journal of Geophysical Research. 104 (D20): 24435–24447. Bibcode:1999JGR...10424435Z. doi:10.1029/1999JD900766.
radio, occultation, remote, sensing, technique, used, measuring, physical, properties, planetary, atmosphere, ring, system, other, satellite, carriers, onboard, gnss, include, champ, satellite, grace, grace, metop, recently, launched, cosmic, analysis, signal,. Radio occultation RO is a remote sensing technique used for measuring the physical properties of a planetary atmosphere or ring system Other satellite carriers onboard GNSS Radio occultation include CHAMP satellite GRACE and GRACE FO MetOp and the recently launched COSMIC 2 1 Radio occultation analysis of signal delay by the tandem FORMOSAT 3 COSMIC used as atmospheric sounding Contents 1 Atmospheric radio occultation 2 GNSS radio occultation 3 Planetary satellite missions 4 Satellite missions 5 See also 6 References 7 External linksAtmospheric radio occultation editAtmospheric radio occultation relies on the detection of a change in a radio signal as it passes through a planet s atmosphere i e as it is occulted by the atmosphere When electromagnetic radiation passes through the atmosphere it is refracted or bent The magnitude of the refraction depends on the gradient of refractivity normal to the path which in turn depends on the density gradient The effect is most pronounced when the radiation traverses a long atmospheric limb path At radio frequencies the amount of bending cannot be measured directly instead the bending can be calculated using the Doppler shift of the signal given the geometry of the emitter and receiver The amount of bending can be related to the refractive index by using an Abel transform on the formula relating bending angle to refractivity In the case of the neutral atmosphere below the ionosphere information on the atmosphere s temperature pressure and water vapor content can be derived by giving radio occultation data applications in meteorology 1 GNSS radio occultation editGNSS radio occultation GNSS RO historically also known as GPS radio occultation GPS RO or GPSRO is a type of radio occultation that relies on radio transmissions from GPS Global Positioning System or more generally from GNSS Global Navigation Satellite System satellites 2 3 This is a relatively new technique first applied in 1995 for performing atmospheric measurements It is used as a weather forecasting tool and could also be harnessed in monitoring climate change The technique involves a low Earth orbit satellite receiving a signal from a GPS satellite The signal has to pass through the atmosphere and gets refracted along the way The magnitude of the refraction depends on the temperature and water vapor concentration in the atmosphere 4 GNSS radio occultation amounts to an almost instantaneous depiction of the atmospheric state The relative position between the GPS satellite and the low Earth orbit satellite changes over time allowing for a vertical scanning of successive layers of the atmosphere 5 GPSRO observations can also be conducted from aircraft 6 or on high mountaintops 7 nbsp Illustration of radio occultationPlanetary satellite missions editCurrent missions include REX on New Horizons 8 Satellite missions editCLARREO Microlab 1 FORMOSAT 3 COSMIC FORMOSAT 7 COSMIC 2 CHAMP GRACE Oceansat Sentinel 6 Michael Freilich GRAS sensor onboard MetOp satellite Spire LEMUR cubesats Yunyao 1See also editAtmospheric limb sounding Bistatic radarReferences edit a b Ding Tong Awange Joseph L Scherllin Pirscher Barbara Kuhn Michael Anyah Richard Zerihun Ayalsew Bui Luyen K 16 September 2022 GNSS Radio Occultation Infilling of the African Radiosonde Data Gaps Reveals Drivers of Tropopause Climate Variability Journal of Geophysical Research Atmospheres 127 17 Bibcode 2022JGRD 12736648D doi 10 1029 2022JD036648 hdl 20 500 11937 91903 S2CID 251652497 Melbourne et al 1994 The application of spacebourne GPS to atmospheric limb sounding and global change monitoring Publication 94 18 Jet Propulsion Laboratory Kursinski et al 1997 Observing the Earth s atmosphere with radio occultation measurements using the Global Positioning System J Geophys Res 102 23 429 23 465 GPS thermometer could flag up climate change Retrieved 2008 02 16 GPS Space Based amp GPS Radio occultation Archived from the original on 2009 05 15 Retrieved 2008 02 16 Xie F Haase J S Syndergaard S 2008 Profiling the atmosphere using the airborne GPS occultation technique A sensitivity study IEEE Transactions on Geoscience and Remote Sensing 46 11 doi 10 1109 TGRS 2008 2004713 S2CID 23345728 Zuffada C Hajj G A Kursinski E R 1999 A novel approach to atmospheric profiling with a mountain based or airborne GPS receiver PDF Journal of Geophysical Research 104 D20 24435 24447 Bibcode 1999JGR 10424435Z doi 10 1029 1999JD900766 Payload Technical Specifications Pluto jhuapl edu Retrieved 2023 01 27 External links editCOSMIC Project Website GeoOptics LLC Website First commercial operational RO Constellation PlanetIQ Website ROM SAF monitoring ROM SAF website ECMWF monitoring GENESIS WebsitePortals nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Outer space nbsp Solar System Retrieved from https en wikipedia org w index php title Radio occultation amp oldid 1200715089, wikipedia, wiki, book, books, library,
