堵河流域致洪暴雨气候特征分析

利用1998～2005年资料对堵河流域面雨量、流域内主要水文站点的流量及堵河下游的黄龙滩水库坝前水位等气象水文要素进行全面分析,给出了堵河流域致洪暴雨标准,分析堵河流域致洪暴雨时空分布特征和环流形势特征。结果表明：①堵河流域致洪暴雨主要为连续性强降水,具有持续时间长的特点。②堵河中上游的西南部及竹溪泉河、竹山官渡河地区对流域降水贡献最大,其次是竹溪河地区。③堵河流域致洪暴雨发生的有利环流特征为：西太平洋副高位置适合;700 hPa在副高和大陆高压间形成东北～西南向幅合带,西南地区低涡发展东移;850 hPa高原南部低值系统发展并逐日东移至重庆地区,在堵河流域附近形成低涡或切变。物理量场特征为：暴雨前高原地区及堵河流域以南地区增暖明显,影响冷空气以偏东路径为主;暴雨925～500 hPa在30～40°N为NEE～SWW走向的等θse密集带,水汽辐合逐渐有利于堵河流域暴雨的发生。

Climatic Characteristics Analysis of Flood-producing Rainstorm in Duhe Drainage Area

Based on the analysis of area rainfall,flow of hydrology stations,water level at Huanglong Dam in downstream of Duhe River basin,the standards of flood-producing rainstorm in Duhe River were given.And the spatial-temporal distribution characteristics of flood-producing rainstorm were analyzed.① Flood-producing rainstorm in Duhe drainage area were mainly caused by continuity heavy rainfall.② The river basin of the southeast of Duhe River were the main origin place of flood.③The heavy rain area was correlated with the location of West Pacific subtropical high,the formation,development and movement of meso-scale convergence disturbances at the low-middle layer.④Before heavy rain,Qinghai-Tibet Plateau and southern of Duhe River were warmer,the energy frontal zone existed at 925-500 hPa in 30-40°N,cold air come from east,water vapour convergence strengthen.