Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean
Global Navigation Satellite Systems reflectometry (GNSS-R) is a particular case of a multistatic radar in which the signals transmitted by navigation satellites are the signals of opportunity. These signals can be processed as a radar scatterometer, as a radar altimeter, or as an unfocused synthetic...
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| Format: | Article |
| Language: | English |
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IEEE
2022-01-01
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| Series: | IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/9911632/ |
| _version_ | 1828343048996651008 |
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| author | Adriano Camps Hyuk Park |
| author_facet | Adriano Camps Hyuk Park |
| author_sort | Adriano Camps |
| collection | DOAJ |
| description | Global Navigation Satellite Systems reflectometry (GNSS-R) is a particular case of a multistatic radar in which the signals transmitted by navigation satellites are the signals of opportunity. These signals can be processed as a radar scatterometer, as a radar altimeter, or as an unfocused synthetic aperture radar. GNSS-R has shown its potential to infer numerous geophysical variables: over land soil moisture, vegetation height, detection of freeze-thaw state, etc., map sea ice extent and type…, and over the ocean wind speed and direction, significant wave height, altimetric measurements or even more recently NASA has released a marine plastics litter product, and some also claim that sea surface salinity (SSS) can be inferred. In addition, retrieval algorithms neglect some of the variations of the delay Doppler map (DDM) that are linked to the observation geometry, i.e., look angle with respect to the speed vectors of the transmitter and receiver. All these different effects impact the DDM peak value and its shape, and may affect the retrieval of geophysical parameters, and ultimately the data interpretation. In this study, the following factors impacting the DDM peak value are studied: the observation geometry, the sea surface temperature, and SSS, the 10 m height wind speed (U<sub>10</sub>) and direction (WD), the presence of foam, the sea development state, the presence of swell, currents, rain, and the presence of oil slicks perturbing the sea surface roughness. This illustrates the complexity of the challenges presented when trying to retrieve some of these variables, the required corrections, and their accuracy. |
| first_indexed | 2024-04-13T23:37:12Z |
| format | Article |
| id | doaj.art-896d29b09b6b499f9fea9d9a23ca5076 |
| institution | Directory Open Access Journal |
| issn | 2151-1535 |
| language | English |
| last_indexed | 2024-04-13T23:37:12Z |
| publishDate | 2022-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing |
| spelling | doaj.art-896d29b09b6b499f9fea9d9a23ca50762022-12-22T02:24:41ZengIEEEIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing2151-15352022-01-01158624863110.1109/JSTARS.2022.32118769911632Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the OceanAdriano Camps0https://orcid.org/0000-0002-9514-4992Hyuk Park1https://orcid.org/0000-0003-0031-0802Department of Signal Theory and Communications, Universitat Politecnica de Catalunya–BarcelonaTech, and IEEC/CTE-UPC, Barcelona, SpainDepartment of Physics, Universitat Politecnica de Catalunya–BarcelonaTech, and IEEC/CTE-UPC, Barcelona, SpainGlobal Navigation Satellite Systems reflectometry (GNSS-R) is a particular case of a multistatic radar in which the signals transmitted by navigation satellites are the signals of opportunity. These signals can be processed as a radar scatterometer, as a radar altimeter, or as an unfocused synthetic aperture radar. GNSS-R has shown its potential to infer numerous geophysical variables: over land soil moisture, vegetation height, detection of freeze-thaw state, etc., map sea ice extent and type…, and over the ocean wind speed and direction, significant wave height, altimetric measurements or even more recently NASA has released a marine plastics litter product, and some also claim that sea surface salinity (SSS) can be inferred. In addition, retrieval algorithms neglect some of the variations of the delay Doppler map (DDM) that are linked to the observation geometry, i.e., look angle with respect to the speed vectors of the transmitter and receiver. All these different effects impact the DDM peak value and its shape, and may affect the retrieval of geophysical parameters, and ultimately the data interpretation. In this study, the following factors impacting the DDM peak value are studied: the observation geometry, the sea surface temperature, and SSS, the 10 m height wind speed (U<sub>10</sub>) and direction (WD), the presence of foam, the sea development state, the presence of swell, currents, rain, and the presence of oil slicks perturbing the sea surface roughness. This illustrates the complexity of the challenges presented when trying to retrieve some of these variables, the required corrections, and their accuracy.https://ieeexplore.ieee.org/document/9911632/Delay doppler mapgeophysical variablesglobal navigation satellite systems reflectometry (GNSS-R)oceansensitivity |
| spellingShingle | Adriano Camps Hyuk Park Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Delay doppler map geophysical variables global navigation satellite systems reflectometry (GNSS-R) ocean sensitivity |
| title | Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean |
| title_full | Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean |
| title_fullStr | Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean |
| title_full_unstemmed | Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean |
| title_short | Sensitivity of Delay Doppler Map in Spaceborne GNSS-R to Geophysical Variables of the Ocean |
| title_sort | sensitivity of delay doppler map in spaceborne gnss r to geophysical variables of the ocean |
| topic | Delay doppler map geophysical variables global navigation satellite systems reflectometry (GNSS-R) ocean sensitivity |
| url | https://ieeexplore.ieee.org/document/9911632/ |
| work_keys_str_mv | AT adrianocamps sensitivityofdelaydopplermapinspacebornegnssrtogeophysicalvariablesoftheocean AT hyukpark sensitivityofdelaydopplermapinspacebornegnssrtogeophysicalvariablesoftheocean |