Spatial clustering of the Qinling-Huaihe region based on precipitation indexes
Precipitation in Qinling-Huaihe region not only varied greatly at both the inter-and intra-annual time scales,but also exhibited strong spatial variability due to complex and diverse landforms,along with unstable monsoon climate.The amount of precipitation amount as well as its variation showed strong regional characteristics over multi-year time scale,especially in case of multi-year annual precipitation.However,the current research adopted study area for the spatial-temporal characteristics analysis of precipitation in Qinling-Huaihe region which is identical to the administrative regions,or was directly bounded by Qinling Mountains or Huaihe River.Therefore,spatial variability of precipitation in Qinling-Huaihe region has not been fully reflected.Three types of precipitation indexes were used to divide the subregions of Qinling-Huaihe with step-wise clustering method.They were the multi-year average precipitation amount at different time scales,including multi-year average(daily,monthly,yearly and five years and 10 years)precipitation amount,the connection numbers of every two stations in terms of the abundant,normal,or dry states of annual precipitation at each site,and the connection number of every two stations based on the trends of annual precipitation change in adjacent years.Average and standard deviation analysis method was used to identify the abundant,normal,or dry states of annual precipitation at each site,assuming that each state had equal probability,and this method was also suitable to identify the trends of increase,decrease,and unchangeability,of annual precipitation change in adjacent years.The Qinling-Huaihe region can be divided into four subregions based on the pentad precipitation according to the indexes of multi-year average precipitation amount at different time scales,namely the subregion between Yangtze and Huaihe,the subregion between Huanghe and Huaihe,the subregion north of Qinling Mountains,and the subregion south of the Qinling Mountains.Furthermore,with the connection number of stations based on the annual precipitation amount of abundant,normal,or dry states,the Qinling-Huaihe region could be divided into four subregions,namely the subregion between Yangtze and Huaihe with multi-year annual precipitation greater than 900 mm,the subregion between Huanghe and Huaihe with multi-year annual precipitation less than 900 mm,the subregion of surrounding area near the junction of Qinling Mountains and Huaihe River,and the subregion containing Loess Plateau Region at the north of Qinling Mountains and west section at the south of the Qinling Mountains.At the same time,with the connection number of stations based on the increase,decrease or unchangeability state of annual precipitation change in adjacent years,the Qinling-Huaihe region could be divided into three regions,namely the subregion between Yangtze and Huaihe,the subregion between Huanghe and Huaihe,and the subregion containing the south and north regions of the Qinling Mountains.After combining the results of subregion with the three precipitation indexes,the Qinling-Huaihe region could be spatially divided into six regions,i.e.,five major subregions and one transitional subregion,namely,the subregion between Yangtze and Huaihe,the subregion between Huanghe and Huaihe,the subregion at the south of Qinling Mountains,the subregion of west section at the north of the Qinling Mountains and the loess Plateau Region at the north of Qinling Mountains,the subregion of Guanzhong Plain and its nearby regions,and the transitional region between Qinling and Huaihe River in north-south orientation.The discordancy measure test was carried out using the L-moment ratios approach,and the results showed that six subregions divided in this study could be considered as homogeneous regions.
dynamic spatial clustering of precipitationpentad rainfallannual precipitation statevariability of annual precipitation in adjacent yearsset pair analysisQinling-Huaihe region
万方数据
维普
