The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation
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 ob...
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ftdukeunivdsp:oai:localhost:10161/4277 2023-11-12T04:13:36+01:00 The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation Medvigy, David Walko, Robert L Otte, Martin J Avissar, Roni 2010 application/pdf https://hdl.handle.net/10161/4277 en_US eng American Meteorological Society 10.1175/2009MWR3131.1 Monthly Weather Review 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. 0027-0644 https://hdl.handle.net/10161/4277 cloud microphysics parameterization part ii numerical-simulation global precipitation boundary-layers arctic stratus climate system rams shallow meteorology & atmospheric sciences Other article 2010 ftdukeunivdsp 2023-10-17T09:38:44Z 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. Version of Record Other/Unknown Material Arctic Duke University Libraries: DukeSpace Arctic |
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Duke University Libraries: DukeSpace |
op_collection_id |
ftdukeunivdsp |
language |
English |
topic |
cloud microphysics parameterization part ii numerical-simulation global precipitation boundary-layers arctic stratus climate system rams shallow meteorology & atmospheric sciences |
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cloud microphysics parameterization part ii numerical-simulation global precipitation boundary-layers arctic stratus climate system rams shallow meteorology & atmospheric sciences Medvigy, David Walko, Robert L Otte, Martin J Avissar, Roni The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation |
topic_facet |
cloud microphysics parameterization part ii numerical-simulation global precipitation boundary-layers arctic stratus climate system rams shallow meteorology & atmospheric sciences |
description |
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. Version of Record |
format |
Other/Unknown Material |
author |
Medvigy, David Walko, Robert L Otte, Martin J Avissar, Roni |
author_facet |
Medvigy, David Walko, Robert L Otte, Martin J Avissar, Roni |
author_sort |
Medvigy, David |
title |
The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation |
title_short |
The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation |
title_full |
The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation |
title_fullStr |
The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation |
title_full_unstemmed |
The Ocean-Land-Atmosphere-Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation |
title_sort |
ocean-land-atmosphere-model: optimization and evaluation of simulated radiative fluxes and precipitation |
publisher |
American Meteorological Society |
publishDate |
2010 |
url |
https://hdl.handle.net/10161/4277 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
10.1175/2009MWR3131.1 Monthly Weather Review 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. 0027-0644 https://hdl.handle.net/10161/4277 |
_version_ |
1782331532832145408 |