Radiative and Convective Driving of Tropical High Clouds
Radiative and Convective Driving of Tropical High Clouds
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热带高云的辐射和对流驱动
DOI：
10.1175/2007jcli1628.1
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发表时间：
2007
影响因子：
4.9
通讯作者：
R. Wood
中科院分区：
文献类型：
--
作者：
T. Kubar;D. Hartmann;R. Wood
使用卫星云数据从Aqua中分辨率成像光谱仪（MODIS）和配置的降水率从先进的微波扫描辐射计（AMSR），它表明，降雨率是密切相关的非常厚的高云，这是一个更好的代理降水比输出长波辐射（OLR）的量。它还表明，薄高云，它有一个积极的净辐射效应的顶部的大气层（TOA）的能量平衡，是丰富的西太平洋相比，东太平洋的近两倍。对于给定的降雨率，铁砧云在西太平洋也更丰富。与西太平洋相比，东太平洋所有高云的集合导致了更多的TOA辐射冷却，主要是因为西太平洋有更多的高云，薄云。在西太平洋，高云也有系统地冷约5 K.作者研究了砧云温度是由低层等效位温（E）更好地预测，还是由与晴空辐射冷却相关的高层辐合峰值更好地预测。对流层上部E与上升凝结层LCL相同的温度似乎影响最冷、最厚云的温度，但与砧云的温度没有简单的关系。相反，它示出的中位砧云顶温度和晴空辐合的峰值温度之间存在线性关系。因此，辐射驱动的晴空辐合廓线与EP中较暖的砧云相一致。
Using satellite cloud data from the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) and collocated precipitation rates from the Advanced Microwave Scanning Radiometer (AMSR), it is shown that rain rate is closely related to the amount of very thick high cloud, which is a better proxy for precipitation than outgoing longwave radiation (OLR). It is also shown that thin high cloud, which has a positive net radiative effect on the top-of-atmosphere (TOA) energy balance, is nearly twice as abundant in the west Pacific compared to the east Pacific. For a given rain rate, anvil cloud is also more abundant in the west Pacific. The ensemble of all high clouds in the east Pacific induces considerably more TOA radiative cooling compared to the west Pacific, primarily because of more high, thin cloud in the west Pacific. High clouds are also systematically colder in the west Pacific by about 5 K. The authors examine whether the anvil cloud temperature is better predicted by low-level equivalent potential temperature (E), or by the peak in upper-level convergence associated with radiative cooling in clear skies. The temperature in the upper troposphere where E is the same as that at the lifting condensation level (LCL) seems to influence the temperatures of the coldest, thickest clouds, but has no simple relation to anvil cloud. It is shown instead that a linear relationship exists between the median anvil cloud-top temperature and the temperature at the peak in clear-sky convergence. The radiatively driven clear-sky convergence profiles are thus consistent with the warmer anvil clouds in the EP versus the WP.