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High cloud variations with surface temperature from 2002 to 2015: Contributions to atmospheric radiative cooling rate and precipitation changes
Author(s) -
Liu Run,
Liou KuoNan,
Su Hui,
Gu Yu,
Zhao Bin,
Jiang Jonathan H.,
Liu Shaw Chen
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd026303
Subject(s) - cloud fraction , cirrus , atmospheric sciences , precipitation , radiative cooling , radiative transfer , cloud forcing , climatology , environmental science , lapse rate , middle latitudes , cloud cover , meteorology , cloud computing , physics , radiative forcing , geology , aerosol , quantum mechanics , computer science , operating system
The global mean precipitation is largely constrained by atmospheric radiative cooling rates ( Q r ), which are sensitive to changes in high cloud fraction. We investigate variations of high cloud fraction with surface temperature ( T s ) from July 2002 to June 2015 and compute their radiative effects on Q r using the Fu‐Liou‐Gu plane‐parallel radiation model. We find that the tropical mean (30°S–30°N) high cloud fraction decreases with increasing T s at a rate of about −1.0 ± 0.34% K −1 from 2002 to 2015, which leads to an enhanced atmospheric cooling around 0.86 W m −2 K −1 . On the other hand, the northern midlatitudes (30°N–60°N) high cloud fraction increases with surface warming at a rate of 1.85 ± 0.65% K −1 and the near‐global mean (60°S–60°N) high cloud fraction shows a statistically insignificant decreasing trend with increasing T s over the analysis period. Dividing high clouds into cirrus, cirrostratus, and deep convective clouds, we find that cirrus cloud fraction increases with surface warming at a rate of 0.32 ± 0.11% K −1 (0.01 ± 0.17% K −1 ) for the near‐global mean (tropical mean), while cirrostratus and deep convective clouds decrease with surface warming at a rate of −0.02 ± 0.18% K −1 and −0.33 ± 0.18% K −1 for the near‐global mean and −0.64 ± 0.23% K −1 and −0.37 ± 0.13% K −1 for the tropical mean, respectively. High cloud fraction response to feedback to T s accounts for approximately 1.9 ± 0.7% and 16.0 ± 6.1% of the increase in precipitation per unit surface warming over the period of 2002–2015 for the near‐global mean and the tropical mean, respectively.