1983-2013年西藏自治区气象灾害时空分布特征与变化趋势

西藏自治区地处青藏高原这一独特的孕灾环境中，气象灾害的频发对当地农牧业、生态环境等敏感领域的影响尤为显著。通过收集西藏自治区1983-2013年气象灾害事件，分析了干旱、雪灾、霜冻、冰雹和洪涝五种灾害的年际、月际、空间分布特征。结果表明：在时间分布上，研究区五种气象灾害在1983-1995年发生总频次呈增涨趋势，1995年后趋于稳定，其中干旱多发生在3-6月，雪灾全年均有发生，霜冻多发生在4月、5月和8月，冰雹和暴雨洪涝灾害季节性强，主要发生在6-9月；在空间分布上，气象灾害高发区分布于西藏自治区南部，其中，干旱多发区分布于日喀则市中东部和山南市北部，雪灾多发区分布于那曲、阿里以及西藏自治区南部边缘地区，霜冻多发区分布于西藏自治区东、南部少数地区，冰雹频发区多呈带状且分布于雅鲁藏布江流域，暴雨洪涝多发区分布于西藏自治区中、东部河谷地带。基于历史气象灾害事件，开展西藏自治区气象灾害的时空分布特征及趋势研究，其结果对农业气象灾害预测预报，区域农业防灾减灾等具有重要的意义。

Temporal and spatial distribution characteristics and changing trend of meteorologic disaster in Tibet Autonomous Region from 1983 through 2013

Tibet autonomous region is located on the Tibetan Plateau, where frequently occurs meteorological disasters, significantly impacting the local agriculture, animal husbandry, ecological environment. The frequent occurrence of meteorological disasters is especially harmful to the sensitive areas, such as agriculture and animal husbandry, and ecological environment. Therefore, based on the historical meteorological disaster events, it is of great significance to carry out a study of the temporal and spatial distribution characteristics and changing trend of meteorological disasters in Tibet Autonomous Region, which can be used for meteorological disaster prediction and disaster prevention and mitigation. In this paper, the annual, monthly and spatial distribution characteristics of drought, snow, frost, hail and flood disasters are analyzed through collecting information of agricultural mete-orological disasters and losses in the region from 1983 through 2013. The results are as follows. In terms of tem-poral distribution, the frequency of the agrometeorological disaster had presented an increasing trend from 1983 to 1995. After 1995, it has changed to stationary. Drought had occurred mostly from March to June. The snow-storm had occurred throughout the year. Frost mostly had occurred in spring and early autumn. Hail and rain flood disasters had characterized of strong seasonality. They almost all had occurred from June to September in summer. In terms of spatial distribution, southern Tibet had been a high incidence area of agricultural meteoro-logical disasters. Drought disasters had occurred mostly in the mid-eastern Xigaze Prefecture and the northern Lhoka Prefecture. The snowstorms had easy appeared widely in Nagqu Prefecture, Ali Prefecture and the south-ern edge of the Tibet Autonomous Region. The influence scope of frost disaster had been the least, which had occurred only in some eastern and southern areas. Hail disasters had showed zonal distribution, which had oc-curred mostly in the Yarlung Zangbo River basin. Storm flood disasters had been prone to occur in the mid-east-ern valley areas. This research has great significance to the regional agricultural disaster prevention and mitiga-tion.