Consistency between the NASS Soil Moisture Condition Table and the SMAP L4SM Product
Abstract
USDA National Agricultural Statistics Service (NASS) produces weekly soil moisture (SM) condition for each US state. The tables indicate the percentage of cultivated land area that have SM conditions corresponding to four levels of water availability in relation to the crop growth stage (the levels are very short, short, adequate and surplus). NASS generates these tables based on field surveys in each state conducted by local respondents based on their experience of the local land and crop conditions. The assessment includes determination of surface and root-zone SM conditions. Even though the surveys follow a common protocol, the results of these surveys are inherently subjective. NASA launched the SMAP (Soil Moisture Active Passive) mission in early 2015. The objective of the mission is global SM and soil freeze/thaw measurements. Alongside SM measurements, the mission produces Level 4 model-based data assimilation products for surface and root-zone SM over a 9-km global grid. The objective of this study is to find out whether the SMAP produced SM is consistent with the NASS SM conditions. The analysis uses statistical matching of SMAP SM and SM condition fraction to find threshold values in each state for different SM conditions. The results show that the threshold values derived from SMAP behave in a consistent manner over the seasonal cycle of vegetation growth. This is an indication that it is possible to derive the SM condition from the objectively generated SMAP products that is consistent with the NASS values that are based on the subjective surveys. Furthermore, the results demonstrated that the SMAP SM can be used to generate SM conditions maps at 9-km resolution at daily temporal fidelity. Acknowledgement: The research described in this abstract was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H51W1638C
- Keywords:
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- 1833 Hydroclimatology;
- HYDROLOGYDE: 1843 Land/atmosphere interactions;
- HYDROLOGYDE: 1855 Remote sensing;
- HYDROLOGYDE: 1866 Soil moisture;
- HYDROLOGY