| Paper: | TH-A2.20 |
| Session: | Applications of Radiometry II |
| Time: | Thursday, March 29, 09:00 - 10:20 |
| Presentation: |
Poster
|
| Topic: |
Theory, physical principles and electromagnetic models: |
| Title: |
High-Resolution Enhanced Product based on SMAP Active Passive Approach using Sentinel 1A and 1B SAR Data |
| Authors: |
Narendra Das; NASA Jet Propulsion Laboratory | | |
| | Dara Entekhabi; Massachusetts Institute of Technology | | |
| | R. Scott Dunbar; NASA Jet Propulsion Laboratory | | |
| | Seungbum Kim; NASA Jet Propulsion Laboratory | | |
| | Simon Yueh; NASA Jet Propulsion Laboratory | | |
| | Andreas Colliander; NASA Jet Propulsion Laboratory | | |
| | Thomas Jagdhuber; German Aerospace Center | | |
| | Jeffrey Walker; Monash University | | |
| Abstract: |
NASA’s Soil Moisture Active Passive (SMAP) mission was launched on January 31st, 2015. SMAP utilized an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna until July 7th, 2015, when the SMAP radar encountered an anomaly and became inoperable. During the SMAP post-radar phase, many ways have been explored to recover the high-resolution soil moisture capability of the SMAP mission. One of the feasible approaches is to substitute the SMAP radar with other available SAR data. Sentinel 1A/1B SAR data has been found most suitable for combining with the SMAP radiometer data because of its almost similar orbit configuration that allows overlapping of their swaths with minimal time difference, which is key to the SMAP active-passive algorithm. The Sentinel SDV (Standard Dual VV+VH)-mode acquisition also provides the co-pol and cross-pol observations required for the SMAP Active Passive algorithm. Some differences do exist between the SMAP SAR data and Sentinel SAR data. They are mainly: 1) Sentinel has C-band SAR and SMAP is L-band; 2) Sentinel has multi incidence angle within its swath, and SMAP has single incidence angle; and 3) Sentinel swath width is ~300 km as compared to SMAP 1000 km swath width. On any given day, the narrow swath width of the Sentinel observations will significantly reduce the spatial coverage of the SMAP active-passive approach as compared to the SMAP swath coverage. The temporal resolution (revisit interval) is also degraded from 3 days to 12 days. One advantage of using Sentinel 1A/1B data in the SMAP Active Passive algorithm is the potential of obtaining the disaggregated brightness temperature and thus soil moisture at a much finer spatial resolution of 3 km. The Beta version of the SMAP-Sentinel Active Passive high-resolution product is now available to the public (released on Nov 1st, 2017) through NSIDC (NASA DAAC). The duration of this product is from May 2015 to current date. The presentation will focus on the basics of the Active Passive algorithm, the characteristics and evolution of the algorithm parameters over different landcover and seasons, and major details of the SMAP-Sentinel Active Passive product. |
