Possible Extensions to the Orographic Drag Scheme in ACME

Wednesday, May 6, 2015 - 07:00
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The orographic gravity wave drag (OGWD) parameterization in CESM1.3, which forms the basis for the ACME model does not include the effects of low-level flow blocking or topographic anisotropy, i.e., ridge orientation. These effects were introduced in many atmospheric models during the early 2000's and found to improve performance in climate and forecast simulations. This presentation will describe an extended OGWD scheme for CAM/ACME that includes low-level blocking and anisotropy. Evaluation using climate simulations as well as short term forecasts initialized with ERA-Interim reanalysis will be discussed. Independent validation of low-level winds and momentum tendencies from the MERRA reanalysis will also be shown.