Abstract | ||
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Disaggregation based on Physical And Theoretical scale Change (DisPATCh) is an algorithm dedicated to the disaggregation of soil moisture observations using high-resolution soil temperature data. DisPATCh converts soil temperature fields into soil moisture fields given a semi-empirical soil evaporative efficiency model and a first-order Taylor series expansion around the field-mean soil moisture. In this study, the disaggregation approach is applied to Soil Moisture and Ocean Salinity (SMOS) satellite data over the 500 km by 100 km Australian Airborne Calibration/validation Experiments for SMOS (AACES) area. The 40-km resolution SMOS surface soil moisture pixels are disaggregated at 1-km resolution using the soil skin temperature derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data, and subsequently compared with the AACES intensive ground measurements aggregated at 1-km resolution. The objective is to test DisPATCh under various surface and atmospheric conditions. It is found that the accuracy of disaggregation products varies greatly according to season: while the correlation coefficient between disaggregated and in situ soil moisture is about 0.7 during the summer AACES, it is approximately zero during the winter AACES, consistent with a weaker coupling between evaporation and surface soil moisture in temperate than in semi-arid climate. Moreover, during the summer AACES, the correlation coefficient between disaggregated and in situ soil moisture is increased from 0.70 to 0.85, by separating the 1-km pixels where MODIS temperature is mainly controlled by soil evaporation, from those where MODIS temperature is controlled by both soil evaporation and vegetation transpiration. It is also found that the 5-km resolution atmospheric correction of the official MODIS temperature data has a significant impact on DisPATCh output. An alternative atmospheric correction at 40-km resolution increases the correlation coefficient between disaggregated and in - itu soil moisture from 0.72 to 0.82 during the summer AACES. Results indicate that DisPATCh has a strong potential in low-vegetated semi-arid areas where it can be used as a tool to evaluate SMOS data (by reducing the mismatch in spatial extent between SMOS observations and localized in situ measurements), and as a further step, to derive a 1-km resolution soil moisture product adapted for large-scale hydrological studies. |
Year | DOI | Venue |
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2012 | 10.1109/TGRS.2011.2175000 | Geoscience and Remote Sensing, IEEE Transactions |
Keywords | Field | DocType |
geophysical techniques,radiometry,soil,AACES intensive ground measurements,Australian Airborne Calibration-validation Experiments,DisPATCh algorithm,DisPATCh output,MODIS data,MODIS temperature data,Moderate Resolution Imaging Spectroradiometer,SMOS AACES area,SMOS satellite data,SMOS soil moisture,Soil Moisture and Ocean Salinity,Southeastern Australia,Taylor series expansion,atmospheric correction,correlation coefficient,field-mean soil moisture,high-resolution soil temperature data,soil evaporative efficiency model,soil moisture disaggregation,soil moisture fields,soil moisture observations,soil temperature fields,surface soil moisture pixels,Australian Airborne Calibration/validation Experiments for SMOS (AACES),Disaggregation based on Physical And Theoretical scale Change (DisPATCh),Moderate Resolution Imaging Spectroradiometer (MODIS),Soil Moisture and Ocean Salinity (SMOS),calibration/validation,disaggregation,field campaign | Atmospheric correction,Correlation coefficient,Soil science,Moderate-resolution imaging spectroradiometer,Vegetation,Evaporation,Remote sensing,Radiometry,Water content,Transpiration,Mathematics | Journal |
Volume | Issue | ISSN |
50 | 5 | 0196-2892 |
Citations | PageRank | References |
6 | 0.85 | 0 |
Authors | ||
7 |
Name | Order | Citations | PageRank |
---|---|---|---|
Olivier Merlin | 1 | 141 | 19.31 |
Christoph Rüdiger | 2 | 190 | 23.56 |
Ahmad Al Bitar | 3 | 261 | 26.44 |
Philippe Richaume | 4 | 269 | 30.37 |
Jeffrey P. Walker | 5 | 231 | 32.78 |
Yann H. Kerr | 6 | 953 | 105.41 |
Al Bitar, A. | 7 | 6 | 0.85 |