Show simple item record Medvigy, David en_US Walko, Robert L. en_US Otte, Martin J. en_US Avissar, Roni en_US 2011-06-21T17:27:48Z 2011-06-21T17:27:48Z 2010 en_US
dc.identifier.citation Medvigy,David;Walko,Robert L.;Otte,Martin J.;Avissar,Roni. 2010. The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation. Monthly Weather Review 138(5): 1923-1939. en_US
dc.identifier.issn 0027-0644 en_US
dc.description.abstract This work continues the presentation and evaluation of the Ocean Land Atmosphere Model (OLAM), focusing on the model's ability to represent radiation and precipitation. OLAM is a new, state-of-the-art earth system model, capable of user-specified grid resolution and local mesh refinement. An objective optimization of the microphysics parameterization is carried out. Data products from the Clouds and the Earth's Radiant Energy System (CERES) and the Global Precipitation Climatology Project (GPCP) are used to construct a maximum likelihood function, and thousands of simulations using different values for key parameters are carried out. Shortwave fluxes are found to be highly sensitive to both the density of cloud droplets and the assumed shape of the cloud droplet diameter distribution function. Because there is considerable uncertainty in which values for these parameters to use in climate models, they are targeted as the tunable parameters of the objective optimization procedure, which identified high-likelihood volumes of parameter space as well as parameter uncertainties and covariances. Once optimized, the model closely matches observed large-scale radiative fluxes and precipitation. The impact of model resolution is also tested. At finer characteristic length scales (CLS), smaller-scale features such as the ITCZ are better resolved. It is also found that the Amazon was much better simulated at 100- than 200-km CLS. Furthermore, a simulation using OLAM's variable resolution functionality to cover South America with 100-km CLS and the rest of the world with 200-km CLS generates a precipitation pattern in the Amazon similar to the global 100-km CLS run. en_US
dc.language.iso en_US en_US
dc.relation.isversionof doi:10.1175/2009MWR3131.1 en_US
dc.subject cloud microphysics parameterization en_US
dc.subject part ii en_US
dc.subject numerical-simulation en_US
dc.subject global precipitation en_US
dc.subject boundary-layers en_US
dc.subject arctic stratus en_US
dc.subject climate en_US
dc.subject system en_US
dc.subject rams en_US
dc.subject shallow en_US
dc.subject meteorology & atmospheric sciences en_US
dc.title The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation en_US
dc.title.alternative en_US
dc.description.version Version of Record en_US 2010-5-0 en_US
duke.description.endpage 1939 en_US
duke.description.issue 5 en_US
duke.description.startpage 1923 en_US
duke.description.volume 138 en_US
dc.relation.journal Monthly Weather Review en_US

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