基于多源降水数据的洞庭湖流域夏季降水与西太平洋副热带高压的关系

基于中国气象科学数据共享服务网提供的1979~2012年夏季6~8月降水实测数据（CMD）和3种不同来源的再分析降水数据,研究和比较副高特征指数与洞庭湖流域夏季降水的关系及空间差异。结果表明：① 6、7月副热带高压（副高）脊线位置偏北,洞庭湖流域大部分区域降水偏多,8月偏少;6、7月北界位置偏北使流域东南降水偏少、西北降水偏多,8月大部分地区降水偏多;6~8月西伸脊点位置东移使降水偏多范围自东向西增大;6月份副高强度增强使东部和南部降水偏多、西部和北部降水偏少,7和8月大部分地区降水减少。② 再分析降水数据大体上能反映出7月份脊线指数、6和7月北界指数、6~8月西伸脊点指数和副高强度指数对相应月份CMD降水的影响。③ 副高特征指数对CMD降水的拟合能力存在区域差异。

Relationship Between Summer Precipitation of Different Data in Dongting Lake and Western Pacific Subtropical High

This study was to compare the relationship between western pacific subtropical High(WPSH) and summer precipitation from different precipitation data in Dongting Lake Basin (107°13'-114°18'E,24°35′-30°27′N). The data included observation precipitation of 27 meteorological stations from China meteorological data sharing service system (CMD), and the reanalysis precipitation data such as European centre for medium-range weather forecasts ERA-Interim reanalyse data (ERA-Interim), climatic research unit time-series version 3.21 of high resolution gridded data of month-by-month variation in climate (CRU-TS 3.21), and the version 2 global precipitation climatology project monthly precipitation analysis (GPCP V2.2). Employed multivariate regression analysis,standard multiple regression equations were set up by using five indices of WPSH and monthly precipitation data from June to August. The distribution and change of the partial regression coefficients of five subtropical high indices were discussed, and the composite influence of subtropical high indices on the precipitation was analyzed by multiple correlation coefficient of every equation. The results indicated that the CMD precipitation in most area of Dongting Lake Basin increased but decreased in August by the position of ridge line moving northward in June and July. The position variation of ridge line in July and August made significant changes in precipitation. For precipitation from ERA-Interim data in June, all reanalysis data in July, CRU data in August, the ridge indice performed the same influence as it did on CMD. With the position of northern boundary moving northward, the precipitation in June and July increased in northwest but decreased in sourtheast, and increased in August in most area of Dongting Lake Basin. The position variation of northern boundary in July and August effected significantly. The influences of northern boundary indice on three reanalysis precipitation data in June and July were similar to that of CMD, but different in July. When the west-extending ridge point position moved easterward, the rainfall area enlarged from east to west, but the precipitation changes in June only was effected significantly by its variation. The influences of west-extending ridge point indice on three reanalysis precipitation data were generally coincident with that of CMD except GPCP in August. There were more precipitation in east and south, but less in west and north because of strengthening Intensity of WPSH in June, which made less precipitation in July and August to most area of Dongting Lake Basin. From June to August, intensity indice did not effect significantly. All three reanalysis data could reflect the influence what the intensity indice did on CMD. According to the methods used in this study, the area indice and the intensity indice showed the reverse effect on precipitation.The fitting ability of five indices of WPSH exhibited differently in time and space for CMD precipitation data. Based on time perspective, the fitting ability in June was better than July and August. Spatially, it showed good fitting ability in west and east of Dongting Lake Basin in June, so did in south and north in July and August. For ERA-Interim, CRU and GPCP data, the fitting ability of five indicators of WPSH in some areas agreed with what CMD showed in June and July. But in August, it had a good consistance with that of CMD in the whole basin for ERA-Interim.