Reduction of thermal stratification due to global warming in winter and spring  

作　　者：Jie LIU Jianming DENG Xiangming TANG 

机构地区：[1]State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China

出　　处：《Journal of Oceanology and Limnology》2025年第1期1-15,共15页海洋湖沼学报(英文)

基　　金：Supported by the 14th Five-Year National Key Research and Development Program of China(No.2022YFC3202004);the National Natural Science Foundation of China(No.42220104010);the Natural Science Foundation of Jiangsu Province(No.BK20220041);the Young Scientists Group Project of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,China(No.E1SL002)。

摘　　要：Global warming has been reported to enhance thermal stratification and decrease the mixlayer depth(MLD)in waters due to higher surface water temperatures,especially in summer.Previous studies were conducted for individual cases or specific periods.At present,there is a lack of global assessments on the influence of climate warming in different seasons on thermal stratification.The ECMWF Reanalysis v5(ERA5)dataset was used to estimate the variability of water body mixing and its drivers in different seasons and regions.Results indicate that global warming could enhance thermal stratification and decrease the MLD globally in summer.Wind speed was the primary driver of MLD changes,followed by temperature.However,ice melt due to global warming enhanced the mixing in icecovered waters in the Northern Hemisphere,and early ice melt led to early mixing.Ice depth was the primary driver of MLD changes in the Northern Hemisphere due to delayed ice formation and earlier melting,while wind speed was the primary driver in other regions or during ice-free seasons.The enhanced mixing due to earlier ice melt out in late winter and early spring could promote water circulation and nutrient turnover,and replenish dissolved oxygen in deep water,thereby promoting the maximum biomass of cyanobacteria and advance harmful algal blooms.

关 键 词：global warming mix-layer depth(MLD) thermal stratification ice depth ECMWF Reanalysis v5(ERA5)dataset 

分 类 号：P467[天文地球—大气科学及气象学] X143[环境科学与工程—环境科学]