Observational Evidence for Two Modes of Coupling Between Sea Surface Temperatures, Tropospheric Temperature Profile, and Shortwave Cloud Radiative Effect in the Tropics
Observational Evidence for Two Modes of Coupling Between Sea Surface Temperatures, Tropospheric Temperature Profile, and Shortwave Cloud Radiative Effect in the Tropics
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DOI：
10.1029/2019gl083990
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发表时间：
2019-08-28
影响因子：
5.2
通讯作者：
Fueglistaler, S.
中科院分区：
文献类型：
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作者：
Fueglistaler, S.
CERES/EBAF v4观测到的热带平均短波云辐射效应(SWCRE)异常可以用观测到的沙洲平均海表面温度(SST)和发生深对流的最暖30%与沙洲(SST#)之差来解释。观测到的对流层温度显示，边界层覆盖强度随时间的变化与SST#的演变一致。CERES/EBAF v4数据证实，较冷水域的相关云量变化是SWCRE的主要原因。在大气环流模式模拟中注意到的这种“模式效应”的观测证据表明，SST#捕捉到了大部分这种效应。观测到的灵敏度(条带上的dSWCRE/d(SST)接近1.8W.m(-2)·K-1，dSWCRE/dSST(#)接近-4.8W.m(-2).K-1)很大程度上反映了厄尔尼诺-南方涛动。随着厄尔尼诺的发展，沙坝上的(SST)增加，SST#减少(两者都增加了SWCRE)。只有在厄尔尼诺高峰期之后，SST#才增加，SWCRE减少。SST#也与热带温度趋势廓线的争议以及赤道太平洋SST趋势观测和模拟之间的差异有关。讨论了因果关系和对未来气候的影响。
Tropical average shortwave cloud radiative effect (SWCRE) anomalies observed by CERES/EBAF v4 are explained by observed average sea surface temperature ((SST) over bar) and the difference between the warmest 30% where deep convection occurs and (SST) over bar (SST#). Observed tropospheric temperatures show variations in boundary layer capping strength over time consistent with the evolution of SST#. The CERES/EBAF v4 data confirm that associated cloud fraction changes over the colder waters dominate SWCRE. This observational evidence for the "pattern effect" noted in General Circulation Model simulations suggests that SST# captures much of this effect. The observed sensitivities (dSWCRE/d (SST) over bar approximate to 1.8W.m(-2).K-1, dSWCRE/dSST(# )approximate to -4.8W.m(-2).K-1) largely reflect El Nino-Southern Oscillation. As El Nino develops, (SST) over bar increases and SST# decreases (both increasing SWCRE). Only after the El Nino peak, SST# increases and SWCRE decreases. SST# is also relevant for the tropical temperature trend profile controversy and the discrepancy between observed and modeled equatorial Pacific SST trends. Causality and implications for future climates are discussed.