西藏古乡沟泥石流与气象条件的关系

Meteorology Conditions for Frequent Debris Flows from Guxiang Valley in Tibet,China

古乡沟位于西藏波密县境内,是发育在念青唐古拉山脉冰川边缘地区的一条大型冰川泥石流沟。自1953年暴发特大泥石流以来,在夏秋季节连续高温或多雨的气候条件下,就会频繁暴发泥石流,几次至百余次不等。为了研究古乡沟泥石流活动与气象条件的关系,以古乡沟1964~1965年暴发的中等及以上规模泥石流（Qmax≥50 m3/s）作为研究对象,结合所在期间（5~9月）的气象资料,通过非参数检验方法,发现泥石流暴发与日降雨R和日最高气温Tmax存在密切关系。最后,分别就多雨（R≥5 mm）和少雨（R〈5 mm）两种气象条件下,分别讨论泥石流暴发概率与降雨和气温的关系,其相关性好。

Destructive debris flows occur frequently at glacierized Mount Nyenchen Tanglha,Bomi,Tibet.Since 1953,hundreds of such flows have occurred in the Guxiang valley during periods of atypically hot or rainy weather in summer or early autumn.In the years of 1964 and 1965,85 and 10 debris flows have been documented respectively by a temporary debris-flow observation station.In this article,25 debris flows with discharge Qmaxabove50 m3/ s occurred in these two yeas are selected as our study object.Supported by the meteorology data,statistical analysis shows that outburst debris flows from Guxiang glacier are highly correlated with atypical weather.Finally,the conditional probability of debris flow from Guxiang glacier,as a function of daily rainfall（ R） and maximum temperature（ Tmax）,for rainy days（ R≥5 mm） and dry days（ R〈 5 mm）,is discussed to predict debris-flow probability.