Publication Abstracts

Kennedy et al. 2010

Kennedy, A.D., X. Dong, B. Xi, P. Minnis, A.D. Del Genio, A.B. Wolf, and M.M. Khaiyer, 2010: Evaluation of the NASA GISS Single Column Model simulated clouds using combined surface and satellite observations. J. Climate, 23, 5175-5192, doi:10.1175/2010JCLI3353.1.

Three years of surface and Geostationary Operational Environmental Satellite (GOES) satellite data at the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site are used to evaluate the NASA GISS Single Column Model (SCM) simulated clouds from January 1999 to December 2001. The GOES derived total cloud fractions for both 0.5° and 2.5° grid boxes are in excellent agreement with surface observations, suggesting that ARM point observations can represent large areal observations. Low (<2 km), middle (2-6 km), and high (>6 km) levels of cloud fractions, however, have negative biases as compared to the ARM results due to multi-layer cloud scenes which can either mask lower cloud layers or cause misidentifications of cloud tops. Compared to the ARM observations, the SCM simulated most mid-level clouds, overestimated low clouds (4%), and underestimated total and high clouds by 7% and 15%, respectively. To examine the dependence of the modeled high and low clouds on the large-scale synoptic patterns and variables such as relative humidity (RH) and pressure vertical velocity (omega), North American Regional Reanalysis (NARR) data are included. The sucessfuly modeled and missed high clouds are primarily associated with a trough and ridge upstream of the ARM SGP, respectively. The PDFs of observed high and low occurrence as a function of RH reveal that high clouds have a Gaussian-like distribution with mode RH values of ∼40-50%, whereas low clouds have a gamma-like distribution with the highest cloud probability occurring at RH ∼ 75-85%. The PDFs of modeled low clouds are similar to those observed, however, for high clouds the PDFs are shifted towards higher values of RH. This results in a negative bias for the modeled high clouds because many of the observed clouds occur at RH values below the SCM specified stratiform parameterization threshold RH of 60%. Despite many similarities between PDFs derived from the NARR and ARM forcing datasets for RH and omega, differences do exist. This warrents further investigation of the forcing and reanalysis datasets.

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BibTeX Citation

  author={Kennedy, A. D. and Dong, X. and Xi, B. and Minnis, P. and Del Genio, A. D. and Wolf, A. B. and Khaiyer, M. M.},
  title={Evaluation of the NASA GISS Single Column Model simulated clouds using combined surface and satellite observations},
  journal={J. Climate},

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RIS Citation

ID  - ke08100v
AU  - Kennedy, A. D.
AU  - Dong, X.
AU  - Xi, B.
AU  - Minnis, P.
AU  - Del Genio, A. D.
AU  - Wolf, A. B.
AU  - Khaiyer, M. M.
PY  - 2010
TI  - Evaluation of the NASA GISS Single Column Model simulated clouds using combined surface and satellite observations
JA  - J. Climate
VL  - 23
SP  - 5175
EP  - 5192
DO  - 10.1175/2010JCLI3353.1
ER  -

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