Abstract: Soil water is a type of water resource. Although there are many methods to monitor the soil water in field, to effectually obtain data of the soil water in macro scale region is a difficult problem when evaluating water cycle. Yellow River is the second river in China, which covers an area of 752 443km 2, so it is important for the water management to calculate the soil water. On the basis of AVHRR-pathfinder data, we employed the Vegetation-Temperature Condition Index (VTCI) to monitor the land surface condition. After checking up the remote sensing data with soil water in the field, we found that VTCI is sensible to the soil water in top soil in Yellow River Basin, which agrees with other achievement. Besides, the data of soil water in field expresses obvious relation of soil water between up layer soil and down layer soil. Therefore, we set up a model to calculate soil water in soil profile (0～1m) in Yellow River Basin by combining meteorological information and remote sensing data. The data used in the research includes AVHRR-pathfinder data during 1982～1998 and soil water, precipitation and evaporation information, which were respectively monitored by 29 agriculture weather stations and 263 national weather stations. Finally, the calculated soil water was compared with survey data and checked up by the method of water balance, and the results are satisfied. It is concluded that our method can be applied in surveying soil water for soil profile in macro scale region during long time and the calculated soil water can be supplied to the research of water cycle in Yellow River Basin.

Key words: remote sensing, soil water, water cycle, Yellow River