Process‐Level Assessment of the Iris Effect Over Tropical Oceans
Process‐Level Assessment of the Iris Effect Over Tropical Oceans
复制标题
热带海洋虹膜效应的过程级评估
DOI：
10.1029/2022gl097997
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发表时间：
2022
影响因子：
5.2
通讯作者：
Masunaga Hirohiko
中科院分区：
文献类型：
--
作者：
Ito Masato;Masunaga Hirohiko
虹膜假说提出了一种云反馈机制，即在较暖的气候中热带砧云部分（CF）的减少可能通过增强的长波辐射来减缓变暖。两种不同的物理过程，一个涉及降水效率，另一个关注对流层上层的稳定性，在文献中被认为是虹膜效应的原因。在这项研究中，A‐Train观测和再分析数据进行了分析，以评估这两个过程。主要调查结果如下：（a）对流层上部稳定度对砧CF的影响很大，正如稳定性虹膜理论所预测的那样;（B）降水效率不太可能控制砧CF，但与中低层CF有关;（c）在日周期上积分时，白天和夜间云辐射效应预计将在很大程度上抵消，表明中性云反馈。
The iris hypothesis suggests a cloud feedback mechanism that a reduction in the tropical anvil cloud fraction (CF) in a warmer climate may act to mitigate the warming by enhanced outgoing longwave radiation. Two different physical processes, one involving precipitation efficiency and the other focusing on upper‐tropospheric stability, have been argued in the literature to be responsible for the iris effect. In this study, A‐Train observations and reanalysis data are analyzed to assess these two processes. Major findings are as follows: (a) the anvil CF changes evidently with upper‐tropospheric stability as expected from the stability iris theory, (b) precipitation efficiency is unlikely to have control on the anvil CF but is related to mid‐ and low‐level CFs, and (c) the day and nighttime cloud radiative effects are expected to largely cancel out when integrated over a diurnal cycle, suggesting a neutral cloud feedback.