温州地区夏季高温气候特征与成因

Climate characters of high temperature and its formation reason in summer in Wenzhou

利用1971—2010年温州地区夏季高温资料,建立温州地区高温过程时间序列,探讨温州地区的高温气候特征和主要天气系统。结果表明:夏季高温日分布具有明显的时间和空间特征,从高温日的年际变化看,温州地区夏季高温自2003年后出现了突增,危害性高温出现频率明显增加;副热带高压是影响温州地区夏季高温的主要天气系统,当本区处于副热带高压脊线附近且为偏西气流,低层有暖中心配合,且日照时数比较长时,将会出现危害性高温;当副热带高压减退温州地区处于西南(或偏西)气流中,850 hPa温度场上华南处于20℃(或以上)的暖区(舌)控制时,日照时数长,本区也易出现高温天气,但出现危害性或强危害性天气的概率较低,此类高温一般出现在6月下旬旬末到7月上中旬;台风等热带低值系统外围的偏北气流引起的强烈下沉增温作用,也会导致温州地区出现高温。

Based on the summer high temperature data from 1971 to 2010 in Wenzhou,the time sequence of high temperature process was built and the climate characters and the main weather systems were discussed. The results indicate that the temporal and spatial characteristics of summer high temperature are significant. The high tempera- ture day increases suddenly since 2003, so is the frequency of hazard high temperature day. The main weather sys- tem influencing summer high temperature is subtropical high. When there is westely air flow,it is located near the ridge line of the subtropical high, there is warm center in the low level, and sunshine duration is long, the hazard high temperature will happen. When subtropical high reduces, it is southwesterly air flow in Wenzhou, it is con- trolled by warm area with above 20 ℃ at 850 hPa in south China, sunshine duration is long, high temperature weather occurs usually in Wenzhou. The above two weather types often appear from the last ten days of June to the first twenty days of July, and their probability is lower. The descending action caused by the north air flow outside the tropical system such as typhoon and so on will lead to high temperature weather ,too.