摘要
使用中国气象局资料中心整编的572个站点1960年1月1日到2005年12月31日日最低温度、日平均气压、日平均风速和北极涛动（A0）指数等气象要素，从一个新的角度分析了我国寒潮时空变化与冬季增暖的联系。寒潮爆发以降温、升压和大风天气为主要特征。定义1日和2日降温达到10℃以上的降温事件为寒潮，大于20℃为极端寒潮。发生在我国的寒潮以北方（35°N以北）最多，其次是中国东部的江南地区。东北的寒潮始于10月，而河套和江南的寒潮在4月份比较频繁。把10月到次年4月寒潮频繁活动的时段确定为冬季风时期。在所有的降温事件中，只有不到1／3的事件伴随有升压和大风天气。过去的45个冬季风期间，寒潮和极端寒潮事件普遍减少，我国新疆、华北、东北和华东减少最为显著，减少的最大幅度达到142次／10a。降温事件、升压频次和大风频次也都在减少。AO指数升高表征了西风带上天气尺度斜压波动的减少和减弱，从而导致我国中高纬度寒潮事件的减少。降温频次的减少在一定程度上导致了冬季最低温度平均值的升高，形成了持续的暖冬。
This study used the data of 572 stations from the China Meteorology Data Sharing Service System, from 1 January 1960 to 31 December 2005. The variables including the daily minimum temperature, mean surface pressure, mean wind speed and the Arctic Oscillation （AO） index were used for analysing the relationship between cold wave events and warm winter in China. The arrival of cold wave is generally characterized by a sharp drop of temperature, steep rise of pressure, and strengthening of wind at the surface In the nationwide view, the temperature drop above 10℃ in one or two days was defined as cold wave, that above 20℃ as extreme cold wave Cold wave occurred most frequently in northern China （north of 35°N） and south parts of the middle-lower reaches of the Yangtze River （i. e , Jiangran）. Climatologically, cold wave began in October in Northeast China. A peak period was found in April over central North China and the Jiangnan. Cold wave was active from October to April, which was the winter monsoon period. Among all temperature drop events, less than one third of them were accompanied with pressure rise and strong wind.
In the last 45 winters, the frequencies of cold waves and extreme cold waves were generally decreasing, significantly in Xinjiang, central North China, Northeast China and East China, with the maximum negative trend about 1 - 2 times per decade. Decreasing trends were observed from those events of temperature drop, pressure rise and strong wind. The increase of AO index denoted the weakening and reducing of baroclinic waves along westerly zone, which was not in favor of the cold wave in China. To some extent, the frequency decrease of temperature drop affected the mean minimum temperature in winter, and led to continuous warm winters.
出处
《大气科学》
CSCD
北大核心
2007年第6期1266-1278,共13页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目40475032
国家重点基础研究发展规划项目2006CB400504
关键词
寒潮
极端事件
气温
变化趋势
cold wave, extreme event, temperature, trend
