The research of soil moisture difference using the delaying effect of the precipitation on the vegetation

摘要

The soil moisture is a very important parameter in many researches, and now the soil moisture is measured mainly in point. A new method to analyze the difference of soil moisture in area scale was advanced. This soil moisture is different from the surface soil moisture, and it is related closely with the vegetation growth. The experiment was conducted in Yellow River Basin in China. The change of vegetation cover is the result from many factors except for the precipitation and temperature, and the soil moisture is an important factor. Based on the anterior research results and our analysis, we postulated that soil moisture in Yellow River Basin is mainly determined by the precipitation. The delaying effect of the precipitation on the vegetation cover was analyzed in the Yellow River Basin using the cross partial correlation index between precipitation and NDVI which reflect the vegetation cover, and the cross partial correlation index has already excluded the impact of temperature on vegetation cover. Because different delaying effect is decided by the soil moisture, different delaying effect represents the different soil moisture. The delaying interval can be adapted to measure soil moisture difference in different level. And on the basis of the above result, the difference of soil moisture in Yellow River Basin was analyzed, and the difference map of soil moisture in Yellow River Basin was made finally.