Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas
Radar altimetry provides information on the topography of the Earth surface. It is commonly used for the monitoring not only sea surface height but also ice sheets topography and inland water levels. The radar altimetry backscattering coefficient, which depends on surface roughness and water content...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-04-01
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| Series: | Remote Sensing |
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| Online Access: | http://www.mdpi.com/2072-4292/10/4/582 |
| _version_ | 1818958388366671872 |
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| author | Christophe Fatras Pierre Borderies Frédéric Frappart Eric Mougin Denis Blumstein Fernando Niño |
| author_facet | Christophe Fatras Pierre Borderies Frédéric Frappart Eric Mougin Denis Blumstein Fernando Niño |
| author_sort | Christophe Fatras |
| collection | DOAJ |
| description | Radar altimetry provides information on the topography of the Earth surface. It is commonly used for the monitoring not only sea surface height but also ice sheets topography and inland water levels. The radar altimetry backscattering coefficient, which depends on surface roughness and water content, can be related to surface properties such as surface soil moisture content. In this study, the influence of surface soil moisture on the radar altimetry echo and backscattering coefficient is analyzed over semi-arid areas. A semi-empirical model of the soil’s complex dielectric permittivity that takes into account that small-scale roughness and large-scale topography was developed to simulate the radar echoes. It was validated using waveforms acquired at Ku and Ka-bands by ENVISAT RA-2 and SARAL AltiKa respectively over several sites in Mali. Correlation coefficients ranging from 0.66 to 0.94 at Ku-band and from 0.27 to 0.96 at Ka-band were found. The increase in surface soil moisture from 0.02 to 0.4 (i.e., the typical range of variations in semi-arid areas) increase the backscattering from 10 to 15 dB between the core of the dry and the maximum of the rainy seasons. |
| first_indexed | 2024-12-20T11:24:57Z |
| format | Article |
| id | doaj.art-5fd741858c7745039ecefff9d8bbd6f9 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-12-20T11:24:57Z |
| publishDate | 2018-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-5fd741858c7745039ecefff9d8bbd6f92022-12-21T19:42:25ZengMDPI AGRemote Sensing2072-42922018-04-0110458210.3390/rs10040582rs10040582Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid AreasChristophe Fatras0Pierre Borderies1Frédéric Frappart2Eric Mougin3Denis Blumstein4Fernando Niño5Office National d’Etudes et de Recherches Aerospatiales (ONERA), 2 Avenue Edouard Belin, 31055 Toulouse CEDEX 4, FranceOffice National d’Etudes et de Recherches Aerospatiales (ONERA), 2 Avenue Edouard Belin, 31055 Toulouse CEDEX 4, FranceGeosciences Environnement Toulouse (GET), UMR 5563, CNRS/IRD/UPS, Observatoire Midi-Pyrenees 8 (OMP), 14 Avenue Edouard Belin, 31400 Toulouse, FranceGeosciences Environnement Toulouse (GET), UMR 5563, CNRS/IRD/UPS, Observatoire Midi-Pyrenees 8 (OMP), 14 Avenue Edouard Belin, 31400 Toulouse, FranceLaboratoire d’Etudes en Geophysique et Oceanographie Spatiales (LEGOS), UMR 5566, CNRS/IRD/UPS, Observatoire Midi-Pyrenees 8 (OMP), 14 Avenue Edouard Belin, 31400 Toulouse, FranceLaboratoire d’Etudes en Geophysique et Oceanographie Spatiales (LEGOS), UMR 5566, CNRS/IRD/UPS, Observatoire Midi-Pyrenees 8 (OMP), 14 Avenue Edouard Belin, 31400 Toulouse, FranceRadar altimetry provides information on the topography of the Earth surface. It is commonly used for the monitoring not only sea surface height but also ice sheets topography and inland water levels. The radar altimetry backscattering coefficient, which depends on surface roughness and water content, can be related to surface properties such as surface soil moisture content. In this study, the influence of surface soil moisture on the radar altimetry echo and backscattering coefficient is analyzed over semi-arid areas. A semi-empirical model of the soil’s complex dielectric permittivity that takes into account that small-scale roughness and large-scale topography was developed to simulate the radar echoes. It was validated using waveforms acquired at Ku and Ka-bands by ENVISAT RA-2 and SARAL AltiKa respectively over several sites in Mali. Correlation coefficients ranging from 0.66 to 0.94 at Ku-band and from 0.27 to 0.96 at Ka-band were found. The increase in surface soil moisture from 0.02 to 0.4 (i.e., the typical range of variations in semi-arid areas) increase the backscattering from 10 to 15 dB between the core of the dry and the maximum of the rainy seasons.http://www.mdpi.com/2072-4292/10/4/582radar altimetrywaveformdielectric permittivitysoil moisture |
| spellingShingle | Christophe Fatras Pierre Borderies Frédéric Frappart Eric Mougin Denis Blumstein Fernando Niño Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas Remote Sensing radar altimetry waveform dielectric permittivity soil moisture |
| title | Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas |
| title_full | Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas |
| title_fullStr | Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas |
| title_full_unstemmed | Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas |
| title_short | Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas |
| title_sort | impact of surface soil moisture variations on radar altimetry echoes at ku and ka bands in semi arid areas |
| topic | radar altimetry waveform dielectric permittivity soil moisture |
| url | http://www.mdpi.com/2072-4292/10/4/582 |
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