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How Well Are Clouds Simulated over Greenland in Climate Models? Consequences for the Surface Cloud Radiative Effect over the Ice Sheet
- Source :
- Journal of Climate, Journal of Climate, American Meteorological Society, 2018, 31 (22), pp.9293-9312. ⟨10.1175/JCLI-D-18-0023.1⟩, Journal of Climate, 2018, 31 (22), pp.9293-9312. ⟨10.1175/JCLI-D-18-0023.1⟩
- Publication Year :
- 2018
- Publisher :
- American Meteorological Society, 2018.
-
Abstract
- Using lidar and radiative flux observations from space and ground, and a lidar simulator, we evaluate clouds simulated by climate models over the Greenland ice sheet, including predicted cloud cover, cloud fraction profile, cloud opacity, and surface cloud radiative effects. The representation of clouds over Greenland is a central concern for the models because clouds impact ice sheet surface melt. We find that over Greenland, most of the models have insufficient cloud cover during summer. In addition, all models create too few nonopaque, liquid-containing clouds optically thin enough to let direct solar radiation reach the surface (−1% to −3.5% at the ground level). Some models create too few opaque clouds. In most climate models, the cloud properties biases identified over all Greenland also apply at Summit, Greenland, proving the value of the ground observatory in model evaluation. At Summit, climate models underestimate cloud radiative effect (CRE) at the surface, especially in summer. The primary driver of the summer CRE biases compared to observations is the underestimation of the cloud cover in summer (−46% to −21%), which leads to an underestimated longwave radiative warming effect (CRELW= −35.7 to −13.6 W m−2compared to the ground observations) and an underestimated shortwave cooling effect (CRESW= +1.5 to +10.5 W m−2compared to the ground observations). Overall, the simulated clouds do not radiatively warm the surface as much as observed.
- Subjects :
- Cloud forcing
Atmospheric Science
010504 meteorology & atmospheric sciences
General circulation models
Greenland ice sheet
[SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology
010502 geochemistry & geophysics
01 natural sciences
Cloud radiative effect
Atmosphere
Radiative flux
Clouds
0105 earth and related environmental sciences
geography
geography.geographical_feature_category
Snowmelt/icemelt
Lidar
[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology
13. Climate action
Climatology
Environmental science
Climate model
Ice sheets
Ice sheet
Subjects
Details
- ISSN :
- 15200442 and 08948755
- Volume :
- 31
- Database :
- OpenAIRE
- Journal :
- Journal of Climate
- Accession number :
- edsair.doi.dedup.....456d41d5647a058d3ea2cb57a7695d77