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Comparison of active microwave soil water content with infrared surface temperatures and surface moisture availability
Author(s) -
Perry Eileen M.,
Carlson Toby N.
Publication year - 1988
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr024i010p01818
Subject(s) - water content , environmental science , soil science , microwave , moisture , radiometer , soil water , scatterometer , atmospheric sciences , remote sensing , meteorology , wind speed , geology , geography , geotechnical engineering , physics , quantum mechanics
Active microwave soil water content and thermal infrared surface temperatures were made simultaneously from an aircraft flying at 400 m over a vegetated region in France. Microwave soil water content was obtained using the French ERASME scatterometer and the surface temperatures with the aid of a PRT‐5 radiometer. Correlations between surface temperature or soil moisture availability (determined from model calculations) and microwave soil moisture were made in both the space (within and between fields) and time domains. With the aid of a model (Carlson, 1986) we estimate a standard error in the infrared temperature and soil moisture availability due to influences other than that of soil moisture. We find that where the standard deviation of the temperature or moisture availability is greater than this standard error (which is the equivalent of about ±2°C), correlations between soil water content and moisture availability become significant and improve with increasing spatial or temporal variance in the measured surface temperatures. When drying is allowed to proceed under strong sunlight for a period of a week or so, the temporal variations in soil moisture become so large that the temporal correlation between surface temperature and soil water content approaches −1.0. On the other hand, spatial correlations over wet terrain show very poor correlation with measured soil moisture.