Analysis of Areal Rainfall Monitoring within Hualin Catchment

Taking two flood processes in Hualin Catchment as an example, the precipitation analysis field P_s and P_r within the basin obtained by the rain gauge interpolation and by the combination of rain gauge and radar data, respectively, were compared. The influences of precipitation fields from different sources on the calculation of areal rainfall and the hydrological response of the catchment were analyzed. The results show that: rain gauge nets with sparse or uneven distribution may miss the heavy precipitation centers, leading to large deviations between the areal rainfall value from P_s and the value from P_r; the difference field (P_r-P_s) of precipitation analysis fields from different sources can intuitively show whether heavy precipitation has occurred in areas without rain gauges, which is helpful to judge the meteorological risk grade of flash flood or geological disaster in these areas. The location, evolution and movement of all heavy precipitation storms leading to a flood peak determine the hydrological response to a large extent, so it is necessary to focus on monitoring whether the heavy precipitation clusters move along the confluence direction of the catchment.