A129-09
Common evaluation/evolution of cloud-radiation processes in 2020 from 25km S2S to 3km NWP

Friday, 11 December 2020: 10:54
Virtual
Stan Benjamin, NOAA Global Systems Laboratory, Boulder, CO, United States, Joseph Olson, University of Colorado at Boulder, Boulder, CO, United States, Shan Sun, University of Colorado Boulder, Boulder, CO, United States, Georg A Grell, NOAA Earth System Research Laboratory, Boulder, CO, United States, Tatiana G Smirnova, NOAA/ESRL/GSD - CIRES, Boulder, CO, United States and Hannah Barnes, University of Washington Seattle Campus, Seattle, WA, United States
Abstract:
Subgrid-scale cloud representation and the closely related surface-energy balance continue to be a central challenge from subseasonal-to-seasonal models down to storm-scale models applied for forecast duration of only a few hours. Previously, NOAA/ESRL confirmed this issue from 3-km model (HRRR using WRF-ARW) for short-range forecasting including sub-grid-scale cloud representation up to a 25-km subseasonal model (FV3-GFS) testing a common suite of scale-aware physical parameterizations.

In a major physics suite component developed during 2018 to 2020-- modified representation of subgrid cloud water in the turbulence MYNN parameterization resulted in much improved agreement with radiation measurements as shown with 2018-2020 testing of the 3km HRRR model. Latest results will be shown using SURFRAD radiation and METAR ceiling observations, indicating much improved bias in downward solar radiation and in cloud location (via mean absolute error metric), as well as with 2m temperature and precipitation.

In addition, new evaluations with the same convection-allowing suite (“mesoscale” suite) of physical parameterizations revised further for subseasonal 30-day tests over summer and winter periods with the 25km NOAA FV3-GFS model. These results are compared with CERES-estimated cloud and downward solar radiation fields. The radiation results from this very preliminary subseasonal test with the ESRL-HRRR physics suite will be compared with previous subseasonal tests using the GFS physics suite and at different horizontal resolution. This global application now confirms much better downward solar-radiation results over oceans for both January and June from a July-2020 version over a 2018 of this “mesoscale” suite.

Background: NOAA Global Systems Laboratory, together with NCAR, has developed this mesoscale scale-aware parameterization suite (turbulent mixing (MYNN – Olson et al 2019), deep/shallow convection (Grell-Freitas), 9-layer land/snow/vegetation/lake model) to improve PBL biases (temperature and moisture) including better representation of clouds and precipitation. This parameterization suite development has been accompanied by an effort for improved data assimilation of clouds, near-surface observations and radar for the atmosphere-land system.

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