不同辐射背景下大西洋热盐环流下沉区混合层深度变化

摘要

基于政府间气候变化专门委员会(Intergovernmental Panel on Climate Change,IPCC)4种最新辐射强迫情景,利用ECHAM5/MPI-OM(European Centre Hamburg Model 5/Max Planck Institute Ocean Model)气候模式输出的1850-2300年逐月混合层深度、海表面温度、海表面盐度数据,分析大西洋热盐环流下沉区混合层深度的变化情况.结果表明:随辐射强迫增加,热盐环流下沉区混合层深度下降,混合层深度振荡周期在格陵兰-冰岛-挪威海(Greenland Sea-Iceland Sea-Norwegian Sea,GIN)海域减小,在拉布拉多海(Labrador Sea,LAB)海域变化不大;与GIN海域相比,LAB海域混合层深度对辐射强迫变化更敏感;两海区温度对混合层深度的影响时间较长,混合层深度对盐度的变化反应迅速;混合层深度变化的主导因素在LAB海域中为盐度,而在GIN海域,低辐射强迫下温度主导混合层深度变化,中高辐射强迫下温度与盐度共同起主导作用.%Based on four radiative forcing scenarios from IPCC (Intergovernmental Panel on Climate Change),we used the ECHAM5/MPI-OM model's outputs (monthly data time from 1850 to 2300),including monthly mixed layer depth data,sea surface data,and sea surface salinity data,to analyze the variability of mixed layer depth in thermohaline circulation (THC) down-welling area.The result shows that along with the radiative forcing rises,the mixed layer depth declined in both down-welling areas,the oscillation period of mixed layer depth declines in Greenland Sea-Iceland Sea-Norwegian Sea area (GIN) when the radiative forcing climbs,which does not occurs in Labrador Sea (LAB) area.The LAB area is more sensitive to the radiative forcing change than the GIN area.In both GIN and LAB areas,the impact of sea surface temperature on mixed layer depth is long-lasting and response of mixed layer depth to sea surface salinity change is prompt.The main factor for inducing variability of mixed layer depth in LAB area is salinity,while in GIN area,it depends on radiative forcing scenarios.