Mechanism of tropical low‐cloud response to surface warming using weather and climate simulations
Mechanism of tropical low‐cloud response to surface warming using weather and climate simulations
复制标题
利用天气和气候模拟热带低云对地表变暖的响应机制
DOI：
10.1002/grl.50474
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发表时间：
2013
影响因子：
5.2
通讯作者：
Y. Kamae
中科院分区：
文献类型：
--
作者：
Satoru Demoto;M. Watanabe;Y. Kamae
为了了解短波云辐射反馈对大气环流模式（GCM）中全球变暖的机制，我们分析了热带云对大气GCM中海表温度均匀增加的响应，采用两种不同的实验设计：一个单一的大气模式相互比较项目（AMIP）运行30年，以及一系列10天的天气后报，随后转置AMIP II（TAMIP）。考虑到云过程的快速时间尺度，后报集合可以捕获AMIP实验中获得的初始瞬态响应，该实验显示热带沉降区低云减少。云的减少发生在前10天在TAMIP当海洋边界层（MBL）是不稳定的，因为在MBL和高空之间的快速和缓慢升温的对比。增强蒸发从海面，应该润湿的MBL通过湍流混合被抑制的表面风速降低与减速的步行者流通。因此，下沉区低云变化的标志大致取决于MBL的对流干燥和湍流增湿之间的竞争。
To understand mechanisms of shortwave cloud‐radiative feedback to global warming in a general circulation model (GCM), we analyzed the response of tropical clouds to uniform increase of sea surface temperature in an atmospheric GCM with two different experimental designs: a single Atmospheric Model Intercomparison Project (AMIP) run for 30 years and a series of 10 day weather hindcasts following the Transpose AMIP II (TAMIP). Given the fast time scale of cloud processes, the hindcast ensemble can capture initial transient responses toward equilibrium obtained in the AMIP experiment, which shows a reduction of low clouds over tropical subsidence regions. The reduction of clouds occurs in the first 10 days in TAMIP when the marine boundary layer (MBL) is destabilized because of contrast between fast and slow warming in the MBL and aloft. Enhanced evaporation from the sea surface that should moisten the MBL through turbulent mixing is suppressed by a reduced surface wind speed associated with a slowdown of the Walker circulation. The sign of the low‐cloud change over the subsidence regime is thus determined roughly by competition between convective drying and turbulent moistening of the MBL.
影响因子：
4.9
作者：
Watanabe, Masahiro;Suzuki, Tatsuo;Kimoto, Masahide
通讯作者：
Kimoto, Masahide