青藏高原东部牧区秋季雪灾天气的形成及预报

对青藏高原东部牧区 (196 7─ 1996年 )秋季发生的成灾性降雪天气过程 ,进行了较为详细的分析。探讨了欧亚区域大型天气系统活动对成灾性降雪天气形势的形成所起的作用 ,指出北冰洋低压槽和西太副高分别是秋季降雪天气形成的主导因素和稳定因素。归纳出三种成灾性降雪天气形成的概念模型。指出高原偏西南风低空急流是高原秋季降雪过程的主要天气系统 ,讨论了急流轴附近的非地转风发展对降雪和最低气温所产生的作用。最后提出了雪灾预报思路

The Forming and Forecasting of Autumn Snow-Disaster Weather in Easten Pastoral-Area of Qinghai-Xizang Plateau

The forming and forecasting analysis of autumn snow disaster weather in the easten pastoral area of Qinghai-Xizang Plateau (hereafter EPAQXP) during the period of 1967\_1996 has been made. The Eurasian weather situations on large scale of forming sonw disaster weather in the EPAQXP are sumed up and classified. The Arctic Ocean trough and subtropical high ridge are pointed out to be dominant and steady factors. The three kinds of weather patterns are sumed up in the forming snow disaster weather, andthe ageostrophic wind near southwest lower-level jet is analyzed in the plateau, and they are showed that the lower-level jet is major snow-produced system and the strong convergence is one of reasons causing heavy snow. The effect of the ageostrophic wind on snowing and creating minimum temperature are discussed. Eventually, some of the indexes for snowing weather forecast are given.