Comparing clouds and their seasonal variations in 10 atmospheric general circulation models with satellite measurements Export

@article{citeulike:176857, abstract = {To assess the current status of climate models in simulating clouds, basic cloud climatologies from ten atmospheric general circulation models are compared with satellite measurements from the International Satellite Cloud Climatology Project (ISCCP) and the Clouds and Earth's Radiant Energy System (CERES) program. An ISCCP simulator is employed in all models to facilitate the comparison. Models simulated a four-fold difference in high-top clouds. There are also, however, large uncertainties in satellite high thin clouds to effectively constrain the models. The majority of models only simulated 30\&\#8211;40\% of middle-top clouds in the ISCCP and CERES data sets. Half of the models underestimated low clouds, while none overestimated them at a statistically significant level. When stratified in the optical thickness ranges, the majority of the models simulated optically thick clouds more than twice the satellite observations. Most models, however, underestimated optically intermediate and thin clouds. Compensations of these clouds biases are used to explain the simulated longwave and shortwave cloud radiative forcing at the top of the atmosphere. Seasonal sensitivities of clouds are also analyzed to compare with observations. Models are shown to simulate seasonal variations better for high clouds than for low clouds. Latitudinal distribution of the seasonal variations correlate with satellite measurements at \>0.9, 0.6\&\#8211;0.9, and \&\#8722;0.2\&\#8211;0.7 levels for high, middle, and low clouds, respectively. The seasonal sensitivities of cloud types are found to strongly depend on the basic cloud climatology in the models. Models that systematically underestimate middle clouds also underestimate seasonal variations, while those that overestimate optically thick clouds also overestimate their seasonal sensitivities. Possible causes of the systematic cloud biases in the models are discussed.}, author = {Zhang, M. H. and Lin, W. Y. and Klein, S. A. and Bacmeister, J. T. and Bony, S. and Cederwall, R. T. and Del Genio, A. D. D. and Hack, J. J. and Loeb, N. G. and Lohmann, U. and Minnis, P. and Musat, I. and Pincus, R. and Stier, P. and Suarez, M. J. and Webb, M. J. and Wu, J. B. and Xie, S. C. and Yao, M. and Zhang, J. H.}, citeulike-article-id = {176857}, citeulike-linkout-0 = {http://www.agu.org/pubs/crossref/2005/2004JD005021.shtml}, citeulike-linkout-1 = {http://dx.doi.org/10.1029/2004JD005021}, citeulike-linkout-2 = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005JGRD..11015S02Z}, day = {3}, doi = {10.1029/2004JD005021}, journal = {Journal of Geophysical Research}, keywords = {climate, cloud, gcm, seasonal}, month = {May}, pages = {D15S02+}, posted-at = {2008-01-03 09:24:43}, priority = {2}, title = {Comparing clouds and their seasonal variations in 10 atmospheric general circulation models with satellite measurements}, url = {http://dx.doi.org/10.1029/2004JD005021}, volume = {110}, year = {2005} }

TY - JOUR ID - citeulike:176857 L3 - citeulike-article-id:176857 N2 - To assess the current status of climate models in simulating clouds, basic cloud climatologies from ten atmospheric general circulation models are compared with satellite measurements from the International Satellite Cloud Climatology Project (ISCCP) and the Clouds and Earth's Radiant Energy System (CERES) program. An ISCCP simulator is employed in all models to facilitate the comparison. Models simulated a four-fold difference in high-top clouds. There are also, however, large uncertainties in satellite high thin clouds to effectively constrain the models. The majority of models only simulated 30–40% of middle-top clouds in the ISCCP and CERES data sets. Half of the models underestimated low clouds, while none overestimated them at a statistically significant level. When stratified in the optical thickness ranges, the majority of the models simulated optically thick clouds more than twice the satellite observations. Most models, however, underestimated optically intermediate and thin clouds. Compensations of these clouds biases are used to explain the simulated longwave and shortwave cloud radiative forcing at the top of the atmosphere. Seasonal sensitivities of clouds are also analyzed to compare with observations. Models are shown to simulate seasonal variations better for high clouds than for low clouds. Latitudinal distribution of the seasonal variations correlate with satellite measurements at >0.9, 0.6–0.9, and −0.2–0.7 levels for high, middle, and low clouds, respectively. The seasonal sensitivities of cloud types are found to strongly depend on the basic cloud climatology in the models. Models that systematically underestimate middle clouds also underestimate seasonal variations, while those that overestimate optically thick clouds also overestimate their seasonal sensitivities. Possible causes of the systematic cloud biases in the models are discussed. JF - Journal of Geophysical Research TI - Comparing clouds and their seasonal variations in 10 atmospheric general circulation models with satellite measurements VL - 110 SP - D15S02 KW - climate KW - cloud KW - gcm KW - seasonal AU - Zhang, MH AU - Lin, WY AU - Klein, SA AU - Bacmeister, JT AU - Bony, S AU - Cederwall, RT AU - Del Genio, ADD AU - Hack, JJ AU - Loeb, NG AU - Lohmann, U AU - Minnis, P AU - Musat, I AU - Pincus, R AU - Stier, P AU - Suarez, MJ AU - Webb, MJ AU - Wu, JB AU - Xie, SC AU - Yao, M AU - Zhang, JH PY - 2005/05/03/ UR - http://dx.doi.org/10.1029/2004JD005021 ER -