The relation between thermal infrared data obtained by airborne MSS measurements and soil moisture content in the Kujukuri Coastal Plain has been investigated.
The results are as follows.
1) Not only the rising rate or variation of the surface radiant temperature but also the surface radiant temperature itself is closely correlated with soil moisture content.
2) For the estimation of soil moisture content based on the thermal infrared data, application of the exponential decay curve or the linear model with the logarithmic transforming for straightness seems to be preferable rather than that of the linear model with the original data, in consideration of the statistical processing and physical properties of the soil. Though the selection of an appropriate model is difficult at a present, the problem should be resolved as a result of future analyses.
3) The moisture content of sandy soil can be estimated on the basis of surface radiant temperature and its rising rate for appropriate periods in a half day. However, for the establishment of soil moisture estimation models in the remote sensing, parameters free from several soil physical properties such as soil textural class, content of certain minerals, porosity, roughness of soil surface, the time of measurement and regional differences, should be developed through normalization using some weather elements which affect the variation of the soil surface temperature physically.
4) Similar experimental studies in other areas and other seasons are necessary for the establishment of the measurement system desired by this study.