东亚中纬度夏季陆面异常增暖与土壤湿度异常的联系
投稿时间: 2018-04-07  最后修改时间: 2018-04-12  点此下载全文
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作者单位E-mail
余波 南京信息工程大学 大气科学学院  
陈海山 南京信息工程大学 气象灾害教育部重点实验室 haishan@nuist.edu.cn 
中文摘要:利用1979-2015年ERA-Interim再分析资料,分析了东亚中纬度夏季陆面热力的时空分布特征及其与前期春季土壤湿度异常的联系,探讨了前期春季土壤湿度影响东亚中纬度夏季陆面热力增暖的可能途径。结果表明,东亚中纬度夏季土壤表层温度呈全区一致增暖趋势,其中贝加尔湖及以南地区温度变化最剧烈、增暖最迅速,且1998年前后存在一个明显由冷向暖转变的年代际转变。进一步分析发现,春、夏季西西伯利亚到贝加尔湖北部地区土壤湿度与夏季贝加尔湖及以南地区土壤表层温度在年代际和年际尺度上均存在紧密联系:西西伯利亚到贝加尔湖北部地区土壤湿度异常偏高,通常对应贝加尔湖及南部地区夏季土壤表层温度偏高。西西伯利亚到贝加尔湖北部地区春、夏土壤湿度异常可以引起夏季大气环流异常,从而对东亚夏季中纬度陆面热力异常产生影响:春、夏土壤湿度偏高时,贝加尔湖及其南部地区上空位势高度正异常,对应异常反气旋性环流,云量会减少,有利于东亚中纬度的陆面增暖;反之,则对应气旋性异常环流,不利于陆面增暖。
中文关键词:东亚中纬度  土壤表层温度  陆面增暖  土壤湿度
 
Linkage between summer land surface warming in mid-latitude of East Asia and soil moisture anomalies
Abstract:Based on the reanalysis data of ERA-Interim during 1979-2015, the linkage between soil moisture anomalies and anomalous land surface warming in the middle latitude of East Asia and possible mechanisms were investigated. Result shows that there is a significant warming of summer land surface in the middle latitude of East Asia with the most rapid and strongest warming happened around the Lake Baikal. Meanwhile, an evident interdecadal transition from the cold state to the warm state was detected around 1998. Further analysis suggests that there are close relationships between spring/summer soil moisture anomalies over regions from the West Siberia to the north of the Lake Baikal and summer soil surface temperature around the Lake Baikal at both interdecadal and interannual scales. Increased spring and summer soil moisture in the West Siberia is usually related to the land surface warming near the Lake Baikal. Anomalous soil moisture can alter the land surface thermal forcing to the atmosphere and thus causes anomalous general circulation. Increased spring and summer soil moisture tends to induce positive geopotential height anomalies and anticyclonic anomalous circulation over the Lake Baikal, which can further reduce summer cloud amount over this region and result in significant land surface warming near the Lake Baikal. On the contrary, decreased spring and summer soil moisture usually produces cyclonic anomalous circulation and increased summer cloud amount around the Lake Baikal, which does not benefit the land surface warming over this region.
keywords:Mid latitude of East Asia  Surface soil temperature  Land surface warming  Soil moisture
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