摘要
鉴于陆气相互作用对极端高温事件的重要作用,利用ERA5-Land陆面再分析资料,分析了基于敏感度的中国区域夏季地表气温与土壤湿度、土壤温度耦合强度的多时间尺度分布特征。研究结果表明,基于不同耦合过程指标定义的陆气耦合强度在中国区域呈不同的空间分布特征,其中基于潜热通量的陆面变量—地表气温耦合的“热点”区域主要分布在中国的西北地区和长江流域,基于感热通量的陆面变量—地表气温耦合的“热点”区域则主要分布在河套—内蒙古地区、新疆西南部地区,以及长江以南部分区域。这说明夏季地表气温对陆面变量异常的敏感度的区域差异,与不同区域陆面异常影响地表气温的主导过程密切相关。此外,陆气耦合强度的强弱还随时间尺度而变化,其中月—季节尺度的陆气耦合强度要明显弱于日、候及旬尺度的耦合强度;就日、候及旬时间尺度而言,基于潜热交换过程的陆面变量—地表气温的耦合强度在全国大部分地区随时间尺度的增加而减弱,基于感热通量的陆气耦合强度在南方大部分地区也随时间尺度的增加逐渐减弱,但在北方大部分地区则表现为随时间尺度增加逐渐增强。相比较于表层土壤湿度与地表气温的耦合强度,次表层土壤湿度与地表气温的耦合强度在中国西北地区明显减弱。
Given the important role of land–atmosphere coupling(LAC)in extreme hot events,the multi-timescale characteristics of sensitivity-based coupling strength,which is between surface air temperature and land surface conditions in summer,were analyzed over China using the ERA5-Land reanalysis dataset.Results show that LAC strength varies remarkably with regions.In particular,the LAC hot spots where variations in land surface conditions considerably influence the surface air temperature through latent heat exchange are primarily located in Northwest China and Yangtze River basin.However,in terms of LAC defined by the sensitivity of surface air temperature to the land condition anomalies through sensible heat exchange,the hot spots are mainly located in the Hetao–Inner Mongolia areas,southwestern Xinjiang,and part of the south Yangtze River.This indicates that the differences in the spatial distribution of LAC indices can be largely explained by the dominant processes,in which land surface anomalies significantly affect the surface air temperature.Moreover,LAC strength varies considerably among different timescales,with monthly LAC strength being significantly weaker than that of shorter timescales(i.e.,daily,pentad,and ten-day).As timescales increasing from one to ten days,the land–air temperature coupling strength based on latent heat flux gets weaker in majority parts of China,while that based on sensible heat flux gets stronger in the northern parts of China but remains a weakened state in other regions.Furthermore,in Northwest China,the coupling strength between the subsurface soil moisture and surface air temperature is weaker than that between the surface soil moisture and surface air temperature.
作者
杨洋
林朝晖
骆利峰
YANG Yang;LIN Zhaohui;and LUO Lifeng(International Center for Climate and Environment Sciences,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;University of Chinese Academy of Sciences,Beijing 100049;Department of Geography,Environment and Spatial Sciences,Michigan State University,Michigan State,East Lansing 48824)
出处
《气候与环境研究》
CSCD
北大核心
2022年第3期333-350,共18页
Climatic and Environmental Research
基金
国家重点研发计划项目2017YFA0604304。
关键词
陆气耦合强度
土壤湿度—气温耦合
土壤温度—气温耦合
耦合时间尺度
Land–atmosphere coupling strength
Soil moisture–air temperature coupling
Soil temperature–air temperature coupling
Coupling timescales
