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DOI	10.5194/acp-22-861-2022
	Albedo susceptibility of northeastern Pacific stratocumulus: the role of covarying meteorological conditions
	Zhang, Jianhao; Zhou, Xiaoli; Goren, Tom; Feingold, Graham
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	861
结束页码	880
卷号	22 期号:2 页码:20
英文摘要	Quantification of the radiative adjustment of marine low clouds to aerosol perturbations, regionally and globally, remains the largest source of uncertainty in assessing current and future climate. One of the important steps towards quantifying the role of aerosol in modifying cloud radiative properties is to quantify the susceptibility of cloud albedo and liquid water path (LWP) to perturbations in cloud droplet number concentration (N-d). We use 10 years of spaceborne observations from the polar-orbiting Aqua satellite to quantify the albedo susceptibility of marine low clouds to Nd perturbations over the northeast (NE) Pacific stratocumulus (Sc) region. Mutual information analysis reveals a dominating control of cloud state (e.g., LWP and N-d) on low-cloud albedo susceptibility, relative to the meteorological states that drive these cloud states. Through a LWP-Nd space decomposition of albedo susceptibilities, we show clear separation among susceptibility regimes (brightening or darkening), consistent with previously established mechanisms through which aerosol modulates cloud properties. These regimes include (i) thin non-precipitating clouds (LWP < 55 g m(-2)) that exhibit brightening (occurring 37 % of the time), corresponding to the Twomey effect; (ii) thicker non-precipitating clouds, corresponding to entrainment-driven negative LWP adjustments that manifest as a darkening regime (36 % of the time); and (iii) another brightening regime (22 % of the time) consisting of mostly precipitating clouds, corresponding to precipitation-suppression LWP positive adjustments. Overall, we find an annual-mean regional low-cloud brightening potential of 20.8 +/- 2.68 W m(-2 )ln(N-d)(-1), despite an overall negative LWP adjustment for non-precipitating marine stratocumulus, owing to the high occurrence of the Twomey-brightening regime. Over the NE Pacific, clear seasonal covariabilities among meteorological factors related to the large-scale circulation are found to play an important role in grouping conditions favorable for each susceptibility regime. When considering the covarying meteorological conditions, our results indicate that for the northeastern Pacific stratocumulus, clouds that exhibit the strongest brightening potential occur most frequently within shallow marine boundary layers over a cool ocean surface with a stable atmosphere and a dry free troposphere above. Clouds that exhibit a darkening potential associated with negative LWP adjustments occur most frequently within deep marine boundary layers in which the atmospheric instability and the ocean surface are not strong and warm enough to produce frequent precipitation. Cloud brightening associated with warm-rain suppression is found to preferably occur either under unstable atmospheric conditions or humid free-tropospheric conditions that co-occur with a warm ocean surface.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000747144300001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273659
作者单位	National Oceanic Atmospheric Admin (NOAA) - USA; University of Colorado System; University of Colorado Boulder; Leipzig University
推荐引用方式 GB/T 7714	Zhang, Jianhao,Zhou, Xiaoli,Goren, Tom,et al. Albedo susceptibility of northeastern Pacific stratocumulus: the role of covarying meteorological conditions[J],2022,22(2):20.
APA	Zhang, Jianhao,Zhou, Xiaoli,Goren, Tom,&Feingold, Graham.(2022).Albedo susceptibility of northeastern Pacific stratocumulus: the role of covarying meteorological conditions.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(2),20.
MLA	Zhang, Jianhao,et al."Albedo susceptibility of northeastern Pacific stratocumulus: the role of covarying meteorological conditions".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.2(2022):20.