中国西北地区气候态变化对极端天气监测的影响

中国西北地区对气候变化的响应极其敏感，西北地区1961-2013年气候变化趋势，分为Ⅰ态（1961-1990年）、Ⅱ态（1971-2000年）、Ⅲ态（1981-2010年）和Ⅳ态（1961-2013年）等4个气候态。利用西北地区年平均气温和降水资料、日最高气温极值和日最大降水量极值资料，基于两种极端天气事件的定义，分析了气候态变化对极端天气监测的影响。结果表明：年平均气温变化受气候态改变的影响较年降水量更为明显。在Ⅰ态和Ⅱ态下进行气温要素评价分析，会突出气温升高的现象，在Ⅲ态下会出现气温降低，气候态改变对降水量等级影响很小。Ⅰ态、Ⅱ态和Ⅲ态下，在20世纪70年代和90年代以来的两个时段内，日极端高温和日极端降水事件均出现增多，其中Ⅰ态增多幅度最大，Ⅲ态的影响最小。在空间分布上，西北地区受气候态影响的敏感区域，主要是新疆北部、青海北部、甘肃中部和东部、宁夏大部和陕西部分地区。

Influence of Climate State Change to Weather Extreme Monitoring in Northwest China

The Northwest China is very sensitive to the climate change. The trend of climate change in Northwest China is divided into four climate states, as Ⅰ state(from 1961 to 1990),Ⅱ state(from 1970 to 2000), Ⅲ state (from 1981 to 2010) and Ⅳ state(from 1961 to 2013). Using the annual average temperature, annual average precipitation, daily max temperature extreme, and daily precipitation extreme data in Northwest China, we analyzed the effect of climate state change on extreme weather monitoring. The results showed that the influence of climate change on average annual temperature was more obvious than annual precipitation. There is the phenomenon of temperature rise under the Ⅰ state and Ⅱ state, and there is the phenomenon of temperature decrease under Ⅲ state during the temperature evaluation analysis. Climate states change have little impact on precipitation levels. The extreme daily max temperature event and extreme daily precipitation event increased under three climate states in 1970s and from 1990s to 2010s, and the amplification is biggest under Ⅰ state, and is most little under Ⅲ state. In Northwest China, the main sensitive areas to the climate states change are northwest Xinjiang, north Qinghai, the center and east of Gansu, most of Ningxia and some area of Shaanxi.