基于美国大气研究中心的CCSM3(Community Climate System Model version 3)模式,对淡水扰动试验中不同大西洋经圈翻转环流(Atlantic Meridional Overturning Circulation,AMOC)平均强度下,中国气候的年代际响应特征进行研究。结果表明:...基于美国大气研究中心的CCSM3(Community Climate System Model version 3)模式,对淡水扰动试验中不同大西洋经圈翻转环流(Atlantic Meridional Overturning Circulation,AMOC)平均强度下,中国气候的年代际响应特征进行研究。结果表明:在年代际尺度上,中国区域地表气温和降水强度变化与AMOC强度变化的关系紧密,然而,不同平均强度下,中国气候的年代际响应特征不同。高平均强度下,中国区域地表气温升高,中国北部降水增多、南部降水减少;低平均强度下,则反之。不同平均强度下,中国区域年平均地表气温和降水EOF第一特征向量的空间分布存在显著差异:高平均强度下,地表气温呈现中国全区域一致的分布型,降水呈现自北向南的“-+-”型的雨带分布;低平均强度下,地表气温呈现中国区域南北反相的偶极子分布型,降水呈现自北向南的“-+”型的雨带分布。与低平均强度相比,在高平均强度下,EOF第一模态的时间系数的年代际变化尺度均更长。展开更多
大西洋经向翻转环流(Atlantic meridional overturning circulation,AMOC)作为全球大洋的极向热量输送带,对大西洋附近区域的天气及全球气候变化都存在至关重要的影响。采用自然资源部第一海洋研究所研发的地球系统模式FIO-ESM v2.0(Fir...大西洋经向翻转环流(Atlantic meridional overturning circulation,AMOC)作为全球大洋的极向热量输送带,对大西洋附近区域的天气及全球气候变化都存在至关重要的影响。采用自然资源部第一海洋研究所研发的地球系统模式FIO-ESM v2.0(First Institute of Oceanography-earth system model version 2.0)分析了1850~2014年AMOC的空间分布特征及时间变化规律,并进一步讨论造成该变化的可能因素。研究结果表明:1850~2014年AMOC最大值出现在40°N、1000 m深度附近,其时间序列总体呈现-0.0791×10^(6)m^(3)/(s·a)的减弱趋势,该期间伴随着Labrador、Irminger海域冬季混合层深度的变浅。通过将模式计算的AMOC强度与RAPID(rapid climate change programme)和OSNAP(overturning in the subpolar North Atlantic program)观测资料进行对比,结合模式间并行比较结果显示该模式能较好地再现观测数据期间的AMOC变化规律。FIO-ESM v2.0模式模拟的AMOC具有55 a左右的年代际周期,Labrador、Irminger海域冬季混合层深度变化揭示的对流变化以及Labrador、GIN海域表层海水密度变化造成的海水下沉对AMOC强度的周期性振荡贡献较明显,其周期性变化与海表盐度(sea surface salinity,SSS)、海表温度(sea surface temperature,SST)、蒸发与降水的差值、北大西洋涛动(North Atlantic oscillation,NAO)等要素的变化密切相关。展开更多
An OGCM, LICOM2.0, was used to investigate the effects of different surface boundary conditions for sea surface salinity （SSS） on simulations of global mean salinity, SSS, and the Atlantic Meridional Overturning Cir...An OGCM, LICOM2.0, was used to investigate the effects of different surface boundary conditions for sea surface salinity （SSS） on simulations of global mean salinity, SSS, and the Atlantic Meridional Overturning Circulation （AMOC）. Four numerical experiments （CTRL, Expl, Exp2 and Exp3） were designed with the same forcing data-set, CORE.v2, and different surface boundary conditions for SSS~ A new surface salinity boundary condition that consists of both virtual and real salt fluxes was adopted in the fourth experiment （Exp3）. Compared with the other experiments, the new salinity boundary condition prohibited a monotonous increasing or decreasing global mean salinity trend. As a result, global salinity was approximately conserved in EXP3. In the default salinity boundary condition setting in LICOM2.0, a weak restoring salinity term plays an essential role in reducing the simulated SSS bias, tending to increase the global mean salinity. However, a strong restoring salinity term under the sea ice can reduce the global mean salinity. The authors also found that adopting simulated SSS in the virtual salt flux instead of constant reference salinity improved the simulation of AMOC, whose strength became closer to that observed.展开更多
文摘基于美国大气研究中心的CCSM3(Community Climate System Model version 3)模式,对淡水扰动试验中不同大西洋经圈翻转环流(Atlantic Meridional Overturning Circulation,AMOC)平均强度下,中国气候的年代际响应特征进行研究。结果表明:在年代际尺度上,中国区域地表气温和降水强度变化与AMOC强度变化的关系紧密,然而,不同平均强度下,中国气候的年代际响应特征不同。高平均强度下,中国区域地表气温升高,中国北部降水增多、南部降水减少;低平均强度下,则反之。不同平均强度下,中国区域年平均地表气温和降水EOF第一特征向量的空间分布存在显著差异:高平均强度下,地表气温呈现中国全区域一致的分布型,降水呈现自北向南的“-+-”型的雨带分布;低平均强度下,地表气温呈现中国区域南北反相的偶极子分布型,降水呈现自北向南的“-+”型的雨带分布。与低平均强度相比,在高平均强度下,EOF第一模态的时间系数的年代际变化尺度均更长。
文摘大西洋经向翻转环流(Atlantic meridional overturning circulation,AMOC)作为全球大洋的极向热量输送带,对大西洋附近区域的天气及全球气候变化都存在至关重要的影响。采用自然资源部第一海洋研究所研发的地球系统模式FIO-ESM v2.0(First Institute of Oceanography-earth system model version 2.0)分析了1850~2014年AMOC的空间分布特征及时间变化规律,并进一步讨论造成该变化的可能因素。研究结果表明:1850~2014年AMOC最大值出现在40°N、1000 m深度附近,其时间序列总体呈现-0.0791×10^(6)m^(3)/(s·a)的减弱趋势,该期间伴随着Labrador、Irminger海域冬季混合层深度的变浅。通过将模式计算的AMOC强度与RAPID(rapid climate change programme)和OSNAP(overturning in the subpolar North Atlantic program)观测资料进行对比,结合模式间并行比较结果显示该模式能较好地再现观测数据期间的AMOC变化规律。FIO-ESM v2.0模式模拟的AMOC具有55 a左右的年代际周期,Labrador、Irminger海域冬季混合层深度变化揭示的对流变化以及Labrador、GIN海域表层海水密度变化造成的海水下沉对AMOC强度的周期性振荡贡献较明显,其周期性变化与海表盐度(sea surface salinity,SSS)、海表温度(sea surface temperature,SST)、蒸发与降水的差值、北大西洋涛动(North Atlantic oscillation,NAO)等要素的变化密切相关。
基金partially supported by the National Basic Research Program of China[grant number 2013CB956204]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010403],[grant number XDA11010304]the National Natural Science Foundation of China[grant number 41305028]
文摘An OGCM, LICOM2.0, was used to investigate the effects of different surface boundary conditions for sea surface salinity （SSS） on simulations of global mean salinity, SSS, and the Atlantic Meridional Overturning Circulation （AMOC）. Four numerical experiments （CTRL, Expl, Exp2 and Exp3） were designed with the same forcing data-set, CORE.v2, and different surface boundary conditions for SSS~ A new surface salinity boundary condition that consists of both virtual and real salt fluxes was adopted in the fourth experiment （Exp3）. Compared with the other experiments, the new salinity boundary condition prohibited a monotonous increasing or decreasing global mean salinity trend. As a result, global salinity was approximately conserved in EXP3. In the default salinity boundary condition setting in LICOM2.0, a weak restoring salinity term plays an essential role in reducing the simulated SSS bias, tending to increase the global mean salinity. However, a strong restoring salinity term under the sea ice can reduce the global mean salinity. The authors also found that adopting simulated SSS in the virtual salt flux instead of constant reference salinity improved the simulation of AMOC, whose strength became closer to that observed.
