In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 19, No. 5 ( 2019-03-04), p. 2813-2832
Abstract:
Abstract. Recent studies have shown that, in response to a surface warming,
the marine tropical low-cloud 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.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-19-2813-2019
DOI:
10.5194/acp-19-2813-2019-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
