东北地区夏季冷暖年大气环流异常的空间特征及演变

GLOBAL CIRCULATION ANOMALOUS SPATIALCHARACTER OF COLD/WARM YEARS INSUMMER IN EASTNORTHERN CHINAAND LONG-PERIOD VARIATION

本文利用40年全球范围的温度场、高度场、UV风场资料,分析东北地区冷暖夏年的大气环流异常空间特征及长期演变。分析结果表明,东北低温冷害是一种时空尺度都很大的灾害性天气气候现象,冷夏年500hPa盛行经向环流,高纬有阻高或暖脊维持,西太平洋副高偏弱,温度场、高度场的垂直分布为伸展至对流层顶的正压结构,纬向呈一波型异常结构,有超长波槽稳定维持于东北地区。冷夏前期,大陆冷高压偏弱,冷空气活跃,冰岛低压和阿留申低压发展较深,太平洋副高持续偏弱,这种状态可以持续到夏季,便形成了东北地区的冷夏。

By using of temperature,height,UV wind field datasets for global 40 years, global circulation anomalous spatial feature of cold/warm years in summer in east-northern China and its long-period variation is analysed. Conclusion shows that low temperature cool injury is a kind of synoptic climatic characteristics, in cold summer years radial circulation prevails in 500hPa geo-potential height, there is blocking high or warm ridge in high-latitude, west Pacific sub-high is weaker,vertical distribution of temperature and height field extends to tropopause,there is an anomalous one-wave structure in zonal direction. In pre-cold summer,continual cold high is weaker,cold air is active,Icelandic low and Aleutian low develop more heavier,Pacific sub-high continues weaker,which can sustain to summer,so that this case leads to cold summer in east-north of China.