Measured Constraints on Cloud Top Entrainment to Reduce Uncertainty of Nonprecipitating Stratocumulus Shortwave Radiative Forcing in the Southern Ocean
Measured Constraints on Cloud Top Entrainment to Reduce Uncertainty of Nonprecipitating Stratocumulus Shortwave Radiative Forcing in the Southern Ocean
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DOI：
10.1029/2020gl090513
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发表时间：
2020-11
影响因子：
5.2
通讯作者：
K. Sanchez;Gregory Charles Roberts;M. Diao;L. Russell
中科院分区：
文献类型：
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作者：
K. Sanchez;Gregory Charles Roberts;M. Diao;L. Russell
层积云顶夹带对云的性质有显著的影响，但很少有观测量化其影响。通过明确的0 - D包模式模拟，初始化云下原位测量，并通过云特性的原位测量验证，南大洋的云顶夹带使短波云辐射强迫（SWCF）减少了100 W m−2。经夹带校正的SWCF的影响是云底气溶胶颗粒浓度或上升气流变化的2至20倍。在估计云强迫时，经夹带校正的SWCF的变率可解释高达50 W m−2的不确定性。估算夹带对云特性影响所需的测量可以从现有的机载平台得到约束，并提供非降水层积云云辐射特性的一阶近似。这些测量得出的夹带估算值可用于验证和改进全球气候模式中夹带的参数化。
Stratocumulus cloud top entrainment has a significant effect on cloud properties, but there are few observations quantifying its impact. Using explicit 0‐D parcel model simulations, initialized with below‐cloud in situ measurements, and validated with in situ measurements of cloud properties, the shortwave cloud radiative forcing (SWCF) was reduced by up to 100 W m−2 by cloud top entrainment in the Southern Ocean. The impact of entrainment‐corrected SWCF is between 2 and 20 times that of changes in the aerosol particle concentration or updraft at cloud base. The variability in entrainment‐corrected SWCF accounts for up to 50 W m−2 uncertainty in estimating cloud forcing. Measurements necessary for estimating the impact of entrainment on cloud properties can be constrained from existing airborne platforms and provide a first‐order approximation for cloud radiative properties of nonprecipitating stratocumulus clouds. These measurement‐derived estimates of entrainment can be used to validate and improve parameterizations of entrainment in Global Climate Models.