Disaggregation Model of Daily Rainfall and Its Application in the Xiaolihe Watershed, Yellow River

In the continuous simulation of the whole sediment process in Coarse Sediment Area, one of the outstanding problems is vetting rainfall data with high spatial and temporal resolution. For the calculation in Digital Watershed Model of Yellow River, one characteristic is huge calculation, as calculation is carried out on each river segment, with 797 river segments in a drainage area of 807km(2). A down-scaling method was proposed which could disaggregate daily rainfall data into one-hour timescale rapidly. This method was based on rain-cell conception and relationships between rainfall depth and duration time grouped by month. Secondly, several event-related characteristics, the distribution of event amount, event start time and the concurrency of number of events on a day of the venerated hourly rainfall series, were compared with the observed data. Thirdly, this method was used in the hydrology simulation of water and sediment erosion in Xiaolihe Watershed. The analysis indicated that, the proposed method could be used to down-scale daily rainfall series to hourly, and then used in the simulation of sediment process with Digital Watershed Model of Yellow River.