Based on the data from 1998 to 2005,area rainfall,flow of main hydrologic stations in Duhe River and upstream water level of the dam of Huanglongtan Reservoir in the lower reaches of Duhe River were analyzed,and the s...Based on the data from 1998 to 2005,area rainfall,flow of main hydrologic stations in Duhe River and upstream water level of the dam of Huanglongtan Reservoir in the lower reaches of Duhe River were analyzed,and the standard of flood-producing rainstorm in Duhe River was given,while temporal and spatial distribution and circulation flow situation characteristic of flood-producing rainstorm in Duhe River were studied.The results showed that the flood-producing rainstorm in Duhe River was mainly continuous intensive precipitation with the characteristic of long duration.There was most rainfall in Zhuxiquan River,Zhushanguandu River and southwest part of the middle and upper reaches of Duhe River,and next came Zhuxi River.Flood-producing rainstorm occurred in Duhe River with some favorable circulation features.For example,it was more favorable in the west Pacific subtropical high,and the convergence zone at northeast-southwest direction was formed between subtropical high and continental high pressure at 700 hPa,while southwest vortex moved eastward.Low pressure system at 850 hPa in south part of plateau developed and moved eastward to Chongqing region and formed low vortex or shear near Duhe River basin.Moreover,the characteristics of physical quantity field were analyzed,the results showed that temperature in plateau area and the south area of Duhe River basin increased obviously before rainstorm,and east pathway was the main path of cold air which affected flood-producing rainstorm in Duhe River.There was a θse intensive belt with NEE-SWW direction at 30°-40° N at 925-500 hPa,and moisture convergence was beneficial to the occurrence of rainstorm in Duhe River.展开更多
利用NCEP/NCAR的逐日再分析资料,分析了2005年6月华南致洪暴雨的环流背景及其可能成因。结果表明:2004—2005年经历的一次弱E l N ino事件是2005年华南致洪暴雨的气候背景。与2005年夏季相比较,6月17—26日强降水期间,华南地区的视加热&...利用NCEP/NCAR的逐日再分析资料,分析了2005年6月华南致洪暴雨的环流背景及其可能成因。结果表明:2004—2005年经历的一次弱E l N ino事件是2005年华南致洪暴雨的气候背景。与2005年夏季相比较,6月17—26日强降水期间,华南地区的视加热<Q1>和视水汽汇<Q2>异常强烈,并且<Q1>和<Q2>的高值带与该时段降水量分布非常相似,高值中心与雨量中心位置基本一致。阿拉伯海东岸和孟加拉湾地区的异常加热源在其西北侧强迫出的高层异常反气旋性环流,使得南亚高压加强偏西。我国大陆处于异常气旋性环流之下,不利于南亚高压北上,有利于南亚高压在青藏高原南部、华南地区维持,使得华南地区位于高空西风急流南侧的上升运动区,有利于该区域强降水发生和维持,形成洪涝。展开更多
文摘Based on the data from 1998 to 2005,area rainfall,flow of main hydrologic stations in Duhe River and upstream water level of the dam of Huanglongtan Reservoir in the lower reaches of Duhe River were analyzed,and the standard of flood-producing rainstorm in Duhe River was given,while temporal and spatial distribution and circulation flow situation characteristic of flood-producing rainstorm in Duhe River were studied.The results showed that the flood-producing rainstorm in Duhe River was mainly continuous intensive precipitation with the characteristic of long duration.There was most rainfall in Zhuxiquan River,Zhushanguandu River and southwest part of the middle and upper reaches of Duhe River,and next came Zhuxi River.Flood-producing rainstorm occurred in Duhe River with some favorable circulation features.For example,it was more favorable in the west Pacific subtropical high,and the convergence zone at northeast-southwest direction was formed between subtropical high and continental high pressure at 700 hPa,while southwest vortex moved eastward.Low pressure system at 850 hPa in south part of plateau developed and moved eastward to Chongqing region and formed low vortex or shear near Duhe River basin.Moreover,the characteristics of physical quantity field were analyzed,the results showed that temperature in plateau area and the south area of Duhe River basin increased obviously before rainstorm,and east pathway was the main path of cold air which affected flood-producing rainstorm in Duhe River.There was a θse intensive belt with NEE-SWW direction at 30°-40° N at 925-500 hPa,and moisture convergence was beneficial to the occurrence of rainstorm in Duhe River.
文摘利用NCEP/NCAR的逐日再分析资料,分析了2005年6月华南致洪暴雨的环流背景及其可能成因。结果表明:2004—2005年经历的一次弱E l N ino事件是2005年华南致洪暴雨的气候背景。与2005年夏季相比较,6月17—26日强降水期间,华南地区的视加热<Q1>和视水汽汇<Q2>异常强烈,并且<Q1>和<Q2>的高值带与该时段降水量分布非常相似,高值中心与雨量中心位置基本一致。阿拉伯海东岸和孟加拉湾地区的异常加热源在其西北侧强迫出的高层异常反气旋性环流,使得南亚高压加强偏西。我国大陆处于异常气旋性环流之下,不利于南亚高压北上,有利于南亚高压在青藏高原南部、华南地区维持,使得华南地区位于高空西风急流南侧的上升运动区,有利于该区域强降水发生和维持,形成洪涝。