The influence of mid-latitude storm tracks on hot, cold, dry and wet extremes.
The influence of mid-latitude storm tracks on hot, cold, dry and wet extremes.
复制标题
DOI：
10.1038/srep17491
复制
发表时间：
2015-12-11
影响因子：
4.6
通讯作者：
Coumou D
中科院分区：
文献类型：
--
作者：
Lehmann J;Coumou D
中纬度环流的变化可对极端天气事件的数量和强度产生重大影响。特别是，高振幅准定常行星波与地表长期极端天气有关。相比之下，快速传播的天气尺度波及其对热极端和冷极端的直接影响的分析很少，虽然这种波的变化已经被检测到，并预计在21世纪世纪。在这里，我们应用天气活动与地面温度和降水的每月网格观测资料的回归分析。我们表明，在中纬度大陆地区的大部分地区，夏季极端高温与低风暴轴活动。在冬季，寒流的出现与北美东部、欧洲和亚洲中部至东部部分地区的低风暴路径活动有关。因此，风暴路径对大陆温度具有缓和作用。显著的风暴路径活动有利于全年的月降雨量极值，而干旱则与缺乏降雨量有关。趋势分析揭示了近几十年来显著的区域变化，有利于美国东部的寒流，加州的干旱和欧亚大陆的极端高温的发生。
Changes in mid-latitude circulation can strongly affect the number and intensity of extreme weather events. In particular, high-amplitude quasi-stationary planetary waves have been linked to prolonged weather extremes at the surface. In contrast, analyses of fast-traveling synoptic-scale waves and their direct influence on heat and cold extremes are scarce though changes in such waves have been detected and are projected for the 21st century. Here we apply regression analyses of synoptic activity with surface temperature and precipitation in monthly gridded observational data. We show that over large parts of mid-latitude continental regions, summer heat extremes are associated with low storm track activity. In winter, the occurrence of cold spells is related to low storm track activity over parts of eastern North America, Europe, and central- to eastern Asia. Storm tracks thus have a moderating effect on continental temperatures. Pronounced storm track activity favors monthly rainfall extremes throughout the year, whereas dry spells are associated with a lack thereof. Trend analyses reveal significant regional changes in recent decades favoring the occurrence of cold spells in the eastern US, droughts in California and heat extremes over Eurasia.