气候变暖背景下西藏地区工程施工气象条件分析

利用降水、气温、积雪、风和相对湿度等影响工程施工建设的气象要素综合定义了工程施工气象指数，根据其对工程施工影响程度分为5级；采用1980—2013年西藏地区38个气象站资料分析了西藏地区工程施工的气候条件特征，以及气候变化背景下西藏地区工程施工气象等级变化，结果表明：气温和降水是影响西藏工程建设气象等级的主要因素，6—9月是西藏地区适宜工程建设期；适宜施工日数自东南向西北减少，适宜施工期开始日自东南向西北推进，适宜施工期结束日自西北向东南推进，海拔越低，适宜施工日数越多、适宜施工期开始越早、适宜施工期结束越晚；随着气候变暖，西藏地区适宜施工日数增加，表现为适宜施工期开始日提前和适宜施工期结束日推迟。

Characteristics of Weather Conditions for Construction Workability in Tibet and in Context of Climate Warming

By means of precipitation, air temperature, snow cover, wind speed, and relative humidity influencing the construction, the Construction Workability Weather Index (CWI) is defined comprehensively. The construction weather conditions are classified in 5 levels according to CWI and their influences. With the data from 38 meteorological stations in Tibet from 1980 to 2013, the climatic conditions for construction workability in Tibet and its changes under the background of global climate change are analyzed. The results show that temperature and precipitation are the main factors that influence the meteorological grades for construction workability in Tibet; June, July, August and September are suitable periods for constructions; the number of suitable days for constructions appears to reduce from southeast to northwest; the start time of suitable periods delays from the southeast to the northwest; and the end time of suitable periods delays form the northwest to the southeast. At lower altitudes, there are more suitable days for construction, the sooner the construction period starts, and later the suitable construction period ends. With global climate warming, the number of suitable days for construction in Tibet increases, and the start time of suitable periods for constructions advances and the end time delays.