As known to all, variance of soil water not only has great impact on regional hydro, but also influences climate greatly through vegetation and soil. Monitoring and simulation of soil moisture are important basis of land sustainable use, planning and management of water re- sources and water-saving technique in agriculture. Therefore, soil water has been up to the a-genda in the Global Soil Wetness Project, and become one of the focuses in the study of Global Climate Change. A critical review on soil moisture monitoring, spatial variability and simulation was carried out in this paper.As a result, it can be concluded that '3S'techniques including Geographical Information System (GIS), Remote Sensing (RS), and Global Position System (GPS) have played an important role in the monitoring soil moisture.The pre-processing, communicating and mining for soil moisture data have been timely dealt with by computer networks in some developed countries.However, many developing countries include China failed to do that.The Geo-statistics theory has already been extensively employed to analyze the spatial pattern and variability of soil moisture, but most existed researches have been done in the fine and small scales, and few researches in coarse scales.After analyzing advantages and disadvantages of the established models for simulating soil moisture, we proposed that integrated non-parameter models should be established to simulate soil moisture by combining '3S' techniques and Geo-statistics theory .This paper is attempts to probe into the study of monitoring and simulating soil moisture and summarize the methods and approaches used in the soil water research, which may be helpful for improving the relevant study in China.
Progress in Geography