Extended Abstract

The representation of the rain gauges in estimating the strength ofrainfall during the “plum rain” in Anhui provinceJiuke Wang, Xiaoyang LiuDepartment of Atmospheric and Oceanic Science, Peking Universitywangjiuke@gmail.comKey word:Rainfall, Rain gage, Representation1 IntroductionIt is widely known that the precipitation has a great influence on human lives, for example,water r esource a rrangement, flood forecast and a gricultures, T herefore, t he quantitativeevaluation o f the s patial distribution of rainfall is of great impotence (Manel E llouze, 200 8).Since a weather surveillance radar c ould cover a h uge ar ea w ith h igh s patial a nd temporalresolution, using radar for precipitation estimation is always the best choice (Lisbeth Pedersen,2008).However, not all of the river basins or interested areas are under the monitoring of radar, themost common way to estimate rainfall is still the use of rain gages. Many hydrologists considerthe rain gauge data to be the “ground truth”, filled the data of rain gauge into the hydrologicalmodel as mean de pth of the r ainfall of a given ar ea, assuming that a single g auge i srepresentative of the entire given area. In some cases, this very assumption leads to a huge error(Lisbeth Pedersen, 2008).The f lood probability, o ne o f t he r esults o f t he h ydrological m odel, is se nsitive t o t hespatial distribution of rainfall, the uncertainty of the spatial distribution of rainfall has importantimpact not only on the properties of floods, such as runoff volumes, but also on the estimationsof hydrological model parameters (Patrick Arnaud, 2001). Therefore, the errors of the data ofthe rain gages, due to the lack of representation, must be determined before further usage.The “plum rain” is a set of processes of precipitation in southeast of China, usually fromJune to July, w hich a lways c ontains floods or ot her hydrologic d isasters. In or der to p rovideaccurately hydrological information, a dense network of rain gages is set up. In general, denserthe network is, more accurate the spatial distribution of rainfall is. However, maintaining o nemore hydrological station or weather station operational is always need good financial supportwhile the accuracy of estimations is not equally improved.Supported by a CINRAD-98D radar located in Hefei, provincial capital of Hefei province,spatial distribution of rainfall with high spatial and temporal resolution can be acquired throughthe joint estimation of radar and network of rain gages. In this research, the relationship betweenthe number of the rain gages and the accuracy of the estimation of rainfall will be analyzed.-119-