SPATIOTEMPORAL CHARACTERISTICS OF HOURLY RAINFALL IN THE UPPER REACHES OF HANJIANG RIVER BASIN

The spatiotemporal distribution of rainfall in. mountainous area has great importance in the prediction and prevention the natural rainfall hazard, such as, flash flood, landslides and debris flow. In the Hanjiang River Basin, rainfall variation patterns, especially the variations of hourly rainfall have not been examined in detailed. This study aims to analysis the spatial patterns of hourly rainfall by a number of statistics, thereby, demonstrating the correlations with the time-scale and geographical features. The result indicates that the frequency of hourly rainfall has significant positive with all the geographical features. The monsoon climate and local terrain information both affect the local short-time scale rainfall, especially in the Northeast part of the watershed. For temporal variations, the shorter time scale rainfall occurs in the midnight on the South part of the watershed, and rainfall from monsoon season dictates the distribution of yearly rainfall. Statistically, the result showed that, the season factor plays an important role in the spatial correlation, based on the empirical model. The spatial correlation coefficients are also increase with the increase of accumulate rainfall time scale. In summary, the results presented in this article demonstrates the distributions of the rainfall regime from the viewpoints of quantitative and qualitative in the upper reaches of Hanjiang River Basin.