Basic studies on the estimations of poor drainage places and groundwater lever by satellite data
1998
Wang, X. (Hokkaido Univ., Sapporo (Japan). Faculty of Agriculture) | Horiguchi, I. | Takeda, T.
The basic studies for estimations of soil moisture and groundwater level were performed using surface temperature measured on the ground and derived from Landsat data in crop fields of Tokachi Plain. Generally, the areas with low surface temperature are equal to the areas with high soil moisture content and high groundwater level. This relation was confirmed by the ground measurements and Landsat data. On the analyses of Landsat data, the analyzed areas were classified using vegetation index and cluster analysis methods, and the areas with low temperature were calculated for each classification and compared with ground data, because surface temperature depend on surface conditions. The following results are obtained: 1) Surface temperature measured by radiative thermometer has the best correlation with soil moisture of 10-15 cm soil depth, 2) The day that surface temperature has the highest correlation coefficient with soil moisture and groundwater level, is with fine days prior to taking data and has relatively heavy rainfalls (over 11 mm) before 5-9 days, 3) The data of good agreement between the areas with low temperature derived from Landsat data and observation of poor drainage areas, have much rainfall in 5-9 days prior to taking the data and relatively light rainfalls in days before 5-9 days
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