تقرير
An Initial Assessment of a SMAP Soil Moisture Disaggregation Scheme Using TIR Surface Evaporation Data over the Continental United States
| العنوان: | An Initial Assessment of a SMAP Soil Moisture Disaggregation Scheme Using TIR Surface Evaporation Data over the Continental United States |
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| المؤلفون: | Vikalp Mishra, W Lee Ellenburg, Robert E Griffin, John R Mecikalski, James F Cruise, Christopher R Hain, Martha C Anderson |
| المصدر: | International Journal of Applied Earth Observation and Geoinformation. 68 |
| بيانات النشر: | United States: NASA Center for Aerospace Information (CASI), 2018. |
| سنة النشر: | 2018 |
| مصطلحات موضوعية: | Earth Resources And Remote Sensing |
| الوصف: | The Soil Moisture Active Passive (SMAP) mission is dedicated toward global soil moisture mapping. Typically, an L-band microwave radiometer has spatial resolution on the order of 36-40 km, which is too coarse for many specific hydro-meteorological and agricultural applications. With the failure of the SMAP active radar within three months of becoming operational, an intermediate (9-km) and finer (3-km) scale soil moisture product solely from the SMAP mission is no longer possible. Therefore, the focus of this study is a disaggregation of the 36-km resolution SMAP passive-only surface soil moisture (SSM) using the Soil Evaporative Efficiency (SEE) approach to spatial scales of 3-km and 9-km. The SEE was computed using thermal-infrared (TIR) estimation of surface evaporation over Continental U.S. (CONUS). The disaggregation results were compared with the 3 months of SMAP-Active (SMAP-A) and Active/Passive (AP) products, while comparisons with SMAP-Enhanced (SMAP-E), SMAP-Passive (SMAP-P), as well as with more than 180 Soil Climate Analysis Network (SCAN) stations across CONUS were performed for a 19 month period. At the 9-km spatial scale, the TIR-Downscaled data correlated strongly with the SMAP-E SSM both spatially (r = 0.90) and temporally (r = 0.87). In comparison with SCAN observations, overall correlations of 0.49 and 0.47; bias of −0.022 and −0.019 and unbiased RMSD of 0.105 and 0.100 were found for SMAP-E and TIR-Downscaled SSM across the Continental U.S., respectively. At 3-km scale, TIR-Downscaled and SMAP-A had a mean temporal correlation of only 0.27. In terms of gain statistics, the highest percentage of SCAN sites with positive gains (>55%) was observed with the TIR-Downscaled SSM at 9-km. Overall, the TIR-based downscaled SSM showed strong correspondence with SMAP-E; compared to SCAN, and overall both SMAP-E and TIR-Downscaled performed similarly, however, gain statistics show that TIR-Downscaled SSM slightly outperformed SMAP-E. |
| نوع الوثيقة: | Report |
| اللغة: | English |
| تدمد: | 0303-2434 |
| DOI: | 10.1016/j.jag.2018.02.005 |
| URL الوصول: | https://ntrs.nasa.gov/citations/20180002110 |
| ملاحظات: | SCMD-EarthScienceSystem_281945 WBS 281945.02.80.01.36 NNM11AA01A NNX15AN58H |
| رقم الأكسشن: | edsnas.20180002110 |
| قاعدة البيانات: | NASA Technical Reports |
| تدمد: | 03032434 |
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| DOI: | 10.1016/j.jag.2018.02.005 |