Publication Abstracts

Cesana et al. 2019

Cesana, G., A.D. Del Genio, A.S. Ackerman, M. Kelley, G. Elsaesser, A.M. Fridlind, Y. Cheng, and M.-S. Yao, 2019: Evaluating models' response of tropical low clouds to SST forcings using CALIPSO observations. Atmos. Chem. Phys., 19, 2813-2832, doi:10.5194/acp-19-2813-2019.

Recent studies have shown that in response to a surface warming, the marine tropical lowcloud cover (LCC) as observed by passive-sensor satellites substantially decreases, therefore generating a smaller negative value of the top-of-the-atmosphere (TOA) cloud radiative effect (CRE). Here we study the LCC and CRE interannual changes in response to sea surface temperature (SST) forcings in the GISS Model E2 climate model, a developmental version of the GISS Model E3 climate model, and in 12 other climate models, as a function of their ability to represent the vertical structure of the cloud response to SST change against 10 years of CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) observations. The more realistic models (those that satisfy the observational constraint) capture the observed interannual LCC change quite well (ΔLCC/ΔSST = -3.49±1.01 % K-1 vs. ΔLCC/ΔSSTobs = -3.59±0.28 % K-1) while the others largely underestimate it (ΔLCC/ΔSST = -1.32±1.28 % K-1). Consequently, the more realistic models simulate more positive shortwave (SW) feedback (ΔCRE/ΔSST = 2.60±1.13 W m-2 K-1) than the less realistic models (ΔCRE/ΔSST = 0.87±2.63 W m-2 K-1), in better agreement with the observations (ΔCRE/ΔSSTobs = 3±0.26 W m-2 K-1), although slightly underestimated. The ability of the models to represent moist processes within the planetary boundary layer (PBL) and produce persistent stratocumulus (Sc) decks appears crucial to replicating the observed relationship between clouds, radiation and surface temperature. This relationship is different depending on the type of low clouds in the observations. Over stratocumulus regions, cloud-top height increases slightly with SST, accompanied by a large decrease in cloud fraction, whereas over trade cumulus (Cu) regions, cloud fraction decreases everywhere, to a smaller extent.

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BibTeX Citation

  author={Cesana, G. and Del Genio, A. D. and Ackerman, A. S. and Kelley, M. and Elsaesser, G. and Fridlind, A. M. and Cheng, Y. and Yao, M.-S.},
  title={Evaluating models' response of tropical low clouds to SST forcings using CALIPSO observations},
  journal={Atmospheric Chemistry and Physics},

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RIS Citation

ID  - ce02100m
AU  - Cesana, G.
AU  - Del Genio, A. D.
AU  - Ackerman, A. S.
AU  - Kelley, M.
AU  - Elsaesser, G.
AU  - Fridlind, A. M.
AU  - Cheng, Y.
AU  - Yao, M.-S.
PY  - 2019
TI  - Evaluating models' response of tropical low clouds to SST forcings using CALIPSO observations
JA  - Atmos. Chem. Phys.
JO  - Atmospheric Chemistry and Physics
VL  - 19
SP  - 2813
EP  - 2832
DO  - 10.5194/acp-19-2813-2019
ER  -

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