The Seasonal Cycle of Atmospheric Heating and Temperature
The Seasonal Cycle of Atmospheric Heating and Temperature
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DOI：
10.1175/jcli-d-12-00713.1
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发表时间：
2013-07-01
影响因子：
4.9
通讯作者：
Battisti, David S.
中科院分区：
文献类型：
--
作者：
Donohoe, Aaron;Battisti, David S.
大气加热的季节性循环分为两部分：一部分是由于大气中的直接太阳吸收，另一部分是由于通过潜热、感热和辐射热通量从地表到大气的能量通量。观测和耦合的气候模式进行了分析。北方热带外大气的绝大多数季节性加热（观测值中的78%和模式平均值中的67%）是由于大气短波吸收。在南部热带外地区，无论是观测还是模式，大气的季节性加热都完全是由大气短波吸收引起的，地面热通量与大气的季节性加热相反。大气温度的季节循环在北方热带外和南半球近正压区都是地面放大的，在这两种情况下，温度的垂直廓线都反映了季节加热的来源，在北方热带外，陆地和海洋大气加热的季节循环有明显的不同。在陆地上，地表能量通量补充了驱动吸收的短波通量;在海洋上，它们反对吸收的短波通量。这就造成了陆地和海洋上空大气温度的巨大季节差异。由平均西风引起的向下梯度温度平流减弱了陆地上空大气加热的季节性循环，并放大了海洋上空的这种循环。纬向能量输送的季节性周期为4.1 PW。最后，作者研究了11个模型中大气加热的季节性周期的变化，这些模型来自耦合模型相互比较项目（CMIP 3）的第3阶段，这是由于大气中二氧化碳的浓度比工业化前增加了一倍。对流层的季节性加热到处都因水蒸气对短波吸收的增加而加强;在海冰被海洋取代的地方，对流层的季节性加热减少，这增加了气候系统的有效储热库，从而减少了地表和大气之间能量通量的季节性幅度。因此，对流层上部（大气短波吸收增加的地方）温度的季节性幅度增加，而地面（冰融化的地方）温度的季节性幅度减少。
The seasonal cycle of the heating of the atmosphere is divided into a component due to direct solar absorption in the atmosphere and a component due to the flux of energy from the surface to the atmosphere via latent, sensible, and radiative heat fluxes. Both observations and coupled climate models are analyzed. The vast majority of the seasonal heating of the northern extratropics (78% in the observations and 67% in the model average) is due to atmospheric shortwave absorption. In the southern extratropics, the seasonal heating of the atmosphere is entirely due to atmospheric shortwave absorption in both the observations and the models, and the surface heat flux opposes the seasonal heating of the atmosphere. The seasonal cycle of atmospheric temperature is surface amplified in the northern extratropics and nearly barotropic in the Southern Hemisphere; in both cases, the vertical profile of temperature reflects the source of the seasonal heating.In the northern extratropics, the seasonal cycle of atmospheric heating over land differs markedly from that over the ocean. Over the land, the surface energy fluxes complement the driving absorbed shortwave flux; over the ocean, they oppose the absorbed shortwave flux. This gives rise to large seasonal differences in the temperature of the atmosphere over land and ocean. Downgradient temperature advection by the mean westerly winds damps the seasonal cycle of heating of the atmosphere over the land and amplifies it over the ocean. The seasonal cycle in the zonal energy transport is 4.1 PW.Finally, the authors examine the change in the seasonal cycle of atmospheric heating in 11 models from phase 3 of the Coupled Model Intercomparison Project (CMIP3) due to a doubling of atmospheric carbon dioxide from preindustrial concentrations. The seasonal heating of the troposphere is everywhere enhanced by increased shortwave absorption by water vapor; it is reduced where sea ice has been replaced by ocean, which increases the effective heat storage reservoir of the climate system and thereby reduces the seasonal magnitude of energy fluxes between the surface and the atmosphere. As a result, the seasonal amplitude of temperature increases in the upper troposphere (where atmospheric shortwave absorption increases) and decreases at the surface (where the ice melts).