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首页> 外文期刊>Journal of Climate >Cloud effects on the meridional atmospheric energy budget estimated from Clouds and the Earth's Radiant Energy System (CERES) data.
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Cloud effects on the meridional atmospheric energy budget estimated from Clouds and the Earth's Radiant Energy System (CERES) data.

机译：根据云和地球辐射能系统（CERES）数据估算的云对子午大气能量预算的影响。

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摘要

The zonal mean atmospheric cloud radiative effect, defined as the difference between the top-of-the-atmosphere (TOA) and surface cloud radiative effects, is estimated from 3 yr of Clouds and the Earth's Radiant Energy System (CERES) data. The zonal mean shortwave effect is small, though it tends to be positive (warming). This indicates that clouds increase shortwave absorption in the atmosphere, especially in midlatitudes. The zonal mean atmospheric cloud radiative effect is, however, dominated by the longwave effect. The zonal mean longwave effect is positive in the tropics and decreases with latitude to negative values (cooling) in polar regions. The meridional gradient of the cloud effect between midlatitude and polar regions exists even when uncertainties in the cloud effect on the surface enthalpy flux and in the modelled irradiances are taken into account. This indicates that clouds increase the rate of generation of the mean zonal available potential energy. Because the atmospheric cooling effect in polar regions is predominately caused by low-level clouds, which tend to be stationary, it is postulated here that the meridional and vertical gradients of the cloud effect increase the rate of meridional energy transport by the dynamics of the atmosphere from the midlatitudes to the polar region, especially in fall and winter. Clouds then warm the surface in the polar regions except in the Arctic in summer. Clouds, therefore, contribute toward increasing the rate of meridional energy transport from the midlatitudes to the polar regions through the atmosphere.
机译：纬向平均大气云辐射效应（定义为最高大气层（TOA）与地表云辐射效应之间的差异）是根据3年的云和地球辐射能系统（CERES）数据估算得出的。区域平均短波效应很小，尽管趋向于是正的（变暖）。这表明云增加了大气中短波的吸收，特别是在中纬度地区。然而，纬向平均大气云辐射效应主要由长波效应决定。在热带地区纬向平均纬向效应为正，在极地地区则随着纬度降至负值（冷却）而减小。即使考虑到表面焓通量和模拟辐照度的不确定性，中纬度和极地地区之间的云效应也存在子午梯度。这表明云增加了平均纬向可用势能的产生率。由于极地地区的大气冷却效应主要是由低层云引起的，而低层云往往是静止的，因此这里假定云效应的子午和垂直梯度会通过大气动力学增加子午能量传输的速率。从中纬度到极地地区，尤其是在秋季和冬季。然后，夏季除北极以外，云层会加热极地地区的表面。因此，云有助于提高子午线能量通过大气层从中纬度到极地地区的传输速度。

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