青藏高原东部牧区雪灾的气候特征分析

通过对 196 7— 1996年 2 5个测站的雪灾资料分析 ,揭示了青藏高原东部牧区有雪灾期从上年10月到当年 5月长达 8个月 ,雪灾在一年之中有 3个高发月 :11月、3月和 2月 ;雪灾主要发生在巴颜喀拉山南缘和东麓地区 ,近 30a来呈上升趋势。 196 8— 1976年冬春为一较长时段的雪灾发生的低值期 ,从 1977— 1992年有 3个高峰期和 2个低谷期 ,从 1993年开始又进入高发期 ;高原东部牧区冬春雪灾存在着明显的 5 6a的和较弱的 2 3a周期变化。本文中定义发生在 15月的雪灾为后冬雪灾 ,发生在10 12月的雪灾为前冬雪灾。研究表明 ,70年代是前冬雪灾的高发期 ,80年代末到 90年代是后冬雪灾的高发期。雪灾期西太副高的年际差异是雪灾发生年际振荡的一个可能原因

Climatic Character Analyese of Snow Disasters in East Qinghai-Xizang Plateau Livestock Farm

The data set of snow disasters from 1967 to 1996 in 25 stations on the Qinghai-Xizang Plateau livestock farm is analyzed. The results show that the period of snow disasters last 8 months from last October to May. March and April are two high frequency months of snow disasters. The snow disaster on the Qinghai-Xizang Plateau livestock farm is mainly to the south and east of the Bayankalashan mountains and has an increasing trend in recent 30 years. The winter and spring snow disasters were little from 1968 to 1976, had three high periods and two low periods from 1977 to 1992 and have been in a new high period since 1993. There is an obvious 5~6 year cycle and a weak 2~3 year cycle of the snow disaster. We define snow disasters from January to May as the latter winter snow disaster and ones from October to December as the former winter snow disaster. We found that there was high former winter snow disaster in 1970s and was high latter winter snow disaster in the period from the end of 1980s to 1990s. The inter-annual anomaly of the subtropical high in the West Pacific Ocean is a main factor that the snow disaster varies.