Soil moisture content is an essential climate variable that plays an important role in the exchange of water, energy and biochemical fluxes between the land surface and atmosphere at local, regional and global scales. Near surface soil moisture (SSM) content is operationally delivered at low resolution (e.g. >=25 km) by earth observation missions, such as ESA/SMOS, NASA/SMAP and EUMETSAT/ASCAT. However numerous land applications would benefit from the availability of SSM at higher resolution. The launch of the C-band Sentinel-1 (S-1) European Radar Observatory, with its frequent revisit, large geographical coverage and data continuity, has opened new perspectives to SAR derived SSM products and stimulated a large research effort to develop SSM products at high resolution (e.g. 1 km). The objective of Exploit-S-1 has been to demonstrate and quantify the capabilities of the S-1 mission to support systematic SSM product generation at high resolution and at regional/continental scale. A suite of four SSM retrieval methods, based on previous research into C-band soil moisture retrieval, has been selected, tailored to S-1 data and implemented. The selection has been driven by the most promising trade-off among robustness, retrieval accuracy and potential matching with the requirements of different applications, such as numerical weather prediction, watershed management, runoff prediction, estimation of evapotranspiration, flood forecasting, in terms of accuracy, resolution and product frequency. A key component of Exploit-S-1 has been the validation activity. To this regard, Exploit-S-1 has also benefitted from the advice and support of an External Advisory Team (EAT) consisting of International leading experts in microwave SSM retrieval and application that has provided their expertise in all the phases of the project and, particularly, in the validation phase. In addition, a pivotal element of Exploit-S-1 has been the assessment of the optimal pre-processing of S-1 time series for SSM retrieval, which can be considered a standard also for other S-1 retrieval studies. The project has been organized in three main tasks: Scientific Review and Requirements Consolidation, Implementation and Validation, Ideas for further scientific research. Based on the specific characteristics of each retrieval approach, a sensitivity analysis, the assessment of algorithm performance on experimental data, the time series Short term Change Detection (STCD) approach has been selected as the most promising approach for further development as a pre-operational S-1 SSM product and its production has been extended over the entire Mediterranean basin. The developed product is derived from time series of VV&VH S-1 observations and delivered at a spatial resolution of ~1 km. A companion SSM standard deviation product at 1 km is delivered as an additional information layer.
Exploitation of S-1 for Surface Soil Moisture Retrieval at High Resolution - Final Report (D4.2)
Francesco Mattia;Anna Balenzano;GiuseppeSatalino;Francesco Lovergine;
2020
Abstract
Soil moisture content is an essential climate variable that plays an important role in the exchange of water, energy and biochemical fluxes between the land surface and atmosphere at local, regional and global scales. Near surface soil moisture (SSM) content is operationally delivered at low resolution (e.g. >=25 km) by earth observation missions, such as ESA/SMOS, NASA/SMAP and EUMETSAT/ASCAT. However numerous land applications would benefit from the availability of SSM at higher resolution. The launch of the C-band Sentinel-1 (S-1) European Radar Observatory, with its frequent revisit, large geographical coverage and data continuity, has opened new perspectives to SAR derived SSM products and stimulated a large research effort to develop SSM products at high resolution (e.g. 1 km). The objective of Exploit-S-1 has been to demonstrate and quantify the capabilities of the S-1 mission to support systematic SSM product generation at high resolution and at regional/continental scale. A suite of four SSM retrieval methods, based on previous research into C-band soil moisture retrieval, has been selected, tailored to S-1 data and implemented. The selection has been driven by the most promising trade-off among robustness, retrieval accuracy and potential matching with the requirements of different applications, such as numerical weather prediction, watershed management, runoff prediction, estimation of evapotranspiration, flood forecasting, in terms of accuracy, resolution and product frequency. A key component of Exploit-S-1 has been the validation activity. To this regard, Exploit-S-1 has also benefitted from the advice and support of an External Advisory Team (EAT) consisting of International leading experts in microwave SSM retrieval and application that has provided their expertise in all the phases of the project and, particularly, in the validation phase. In addition, a pivotal element of Exploit-S-1 has been the assessment of the optimal pre-processing of S-1 time series for SSM retrieval, which can be considered a standard also for other S-1 retrieval studies. The project has been organized in three main tasks: Scientific Review and Requirements Consolidation, Implementation and Validation, Ideas for further scientific research. Based on the specific characteristics of each retrieval approach, a sensitivity analysis, the assessment of algorithm performance on experimental data, the time series Short term Change Detection (STCD) approach has been selected as the most promising approach for further development as a pre-operational S-1 SSM product and its production has been extended over the entire Mediterranean basin. The developed product is derived from time series of VV&VH S-1 observations and delivered at a spatial resolution of ~1 km. A companion SSM standard deviation product at 1 km is delivered as an additional information layer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
