Characteristics Of Extreme Precipitation In Qinba Mountain Area

The study of extreme precipitation is a significant factor for investigating rainstorms,flash floods,and unpredictable disasters.Located in the transitional climate zone of China,the Qinba mountain is sensitive to extreme climate and rainstorm events.With the widely spatial and temporal scale of TRMM precipitation data at the present,the accuracy and ability of satellite data to measure the extreme precipitation characteristic in this area are still unclear in the mountain region.Thus,it is crucial to investigate the feature of precipitation extremes in this region with satellite data and compare it with gauge data.According to this,the study aims to（1）validate the accuracy of TRMM-3B42V7 precipitation data against the rain gauge data from 1998 to 2014 over Qinba,（2）calculate the 1Day,3Day,5Day,and 7Day extreme precipitation of validated TRMM and gauge data,（3）compare the minimum,medium,maximum 5Day,and 7Day extreme precipitation,（4）calculate the mountain rainstorm by using the 1Day extreme precipitation datasets of TRMM and rain-gauge.Statistical metrics（CC,MBE,RMSE）was used in validation as the performance measure.The 1Day,3Day,5Day,and 7Day extreme precipitation was identified by the 95^th percentile method.The Mountain equivalent rainfall concept was applied to determine the mountain rainstorm.As the results,（1）The validation showed well agreement but better consistency found at the lower-elevated stations.In addition,the evaluation metrics also demonstrated indistinctly topography dependence in this area at both timescales.For the monthly time scale,the highest correlation and less error magnitude values were found at Changqingpu and Jiangkou stations,respectively.For the annual timescale,the highest correlation was found at Gaotan and Changqingpu stations,and the less error magnitude was identified at Nankuanpping station.（2）The percentile method indicated that,overall,the 1Day,3Day,5Day,and 7Day gauges respectively found the highest and lowest threshold at Zhenba and Jiangkou stations,while the satellite-based dataset had the highest and lowest threshold at Gaotan and Taibai station,respectively.（3）Based on the comparison,the TRMM satellite product can capture the extreme precipitation mostly at the station below 433m（R²>0.5）for 5Day datasets,while7Day datasets reveal contrast patterns.（4）By applying the MER concept,the TRMM-based and gauge-based ratio revealed a similar pattern of mountain rainstorms at higher elevations and slightly different in the middle region.The mountain rainstorm amount was double the extreme rainfall at a higher elevation.Therefore,the defined extreme precipitation characteristics can assist the disaster risk reduction and mitigation strategy in the Qinba mountain of Shaanxi and also provide a reference for improving the satellite algorithm in extreme precipitation measurement.