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

2020 ◽  
Author(s):  
Stan Benjamin ◽  
Joseph Joseph Olson ◽  
Shan Sun ◽  
Georg Georg Grell ◽  
Curtis Curtis Alexander
Keyword(s):  
Solar Radiation ◽  
Turbulent Mixing ◽  
Earth System ◽  
Subgrid Scale ◽  
System Research ◽  
Shallow Convection ◽  
Near Surface ◽  
Land System ◽  
Scale Models ◽  
Physical Parameterizations

<p>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.  </p><p>In a major physics suite component -- modified representation of subgrid cloud water 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.</p><p>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 Nov-2019 version over a 2018 of the “mesoscale” suite.</p><p>Background: NOAA Earth System Research Laboratory, together with NCAR, has developed this parameterization suite (turbulent mixing, deep/shallow convection, 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.</p><p>Subgrid-scale cloud representation continues 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) for short-range forecasting including sub-grid-scale cloud representation up to a 60-km subseasonal model testing a common suite of scale-aware physical parameterizations.   Some progress has been made in 2018-2019 to substantially reduce cloud deficiency and excessive downward solar radiation at least over land areas.</p><p>Recent development and refinements to this common suite of physical parameterizations for scale-aware deep/shallow convection and boundary-layer mixing over this wide range of time and spatial scales will be reported in this presentation showing some progress. Evaluation of components of this suite is being evaluated for cloud/radiation (using SURFRAD, CERES, METAR ceiling) and near-surface (METAR, mesonet, aircraft, rawinsonde).</p><p>NOAA Earth System Research Laboratory, together with NCAR, has developed this parameterization suite (turbulent mixing, deep/shallow convection, 9-layer land/snow/vegetation 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.  </p><p>The MYNN boundary-layer EDMF scheme (Olson, et al 2019), RUC land-surface model (Smirnova et al. 2016 MWR), Grell-Freitas scheme (2014, Atmos. Chem. Phys.), and aerosol-aware cloud microphysics (Thompson and Eidhammer 2015) have been applied and tested extensively for the NOAA hourly updated 3-km High-Resolution Rapid Refresh (HRRR) and 13-km Rapid Refresh model/assimilation systems over the United States and North America.   This mesoscale but also scale-aware suite is being tested,</p>

Homogeneity of the Subgrid-Scale Turbulent Mixing in Large-Eddy Simulation of Shallow Convection

2013 ◽  
Vol 70 (9) ◽  
pp. 2751-2767 ◽  
Author(s):  
Dorota Jarecka ◽  
Wojciech W. Grabowski ◽  
Hugh Morrison ◽  
Hanna Pawlowska
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Droplet Radius ◽  
Subgrid Scale ◽  
Shallow Convection ◽  
Eddy Simulation ◽  
Droplet Concentration ◽  
Large Eddy ◽  
Double Moment ◽  
The Mean

Abstract This paper presents an approach to locally predict homogeneity of the subgrid-scale turbulent mixing in large-eddy simulation of shallow clouds applying double-moment warm-rain microphysics. The homogeneity of subgrid-scale mixing refers to the partitioning of the cloud water evaporation due to parameterized entrainment between changes of the mean droplet radius and changes of the mean droplet concentration. Homogeneous and extremely inhomogeneous mixing represent two limits of possible scenarios, where the droplet concentration and the mean droplet radius remains unchanged during the microphysical adjustment, respectively. To predict the subgrid-scale mixing scenario, the double-moment microphysics scheme is merged with the approach to delay droplet evaporation resulting from entrainment. Details of the new scheme and its application in the Barbados Oceanographic and Meteorological Experiment (BOMEX) shallow convection case are discussed. The simulated homogeneity of mixing varies significantly inside small convective clouds, from close to homogeneous to close to extremely inhomogeneous. The mean mixing characteristics become more homogeneous with height, reflecting increases of the mean droplet size and the mean turbulence intensity, both favoring homogeneous mixing. Model results are consistent with microphysical effects of entrainment and mixing deduced from field observations. Mixing close to homogeneous is predicted in volumes with the highest liquid water content (LWC) and strongest updraft at a given height, whereas mixing in strongly diluted volumes is typically close to extremely inhomogeneous. The simulated homogeneity of mixing has a small impact on mean microphysical characteristics. This result agrees with the previous study applying prescribed mixing scenarios and can be explained by the high humidity of the clear air involved in the subgrid-scale mixing.

scholarly journals Explicit Representation of Spatial Subgrid-Scale Heterogeneity in an ESM

2016 ◽  
Vol 17 (5) ◽  
pp. 1357-1371 ◽  
Author(s):  
Philipp de Vrese ◽  
Stefan Hagemann
Keyword(s):  
Land Surface ◽  
Large Fraction ◽  
Atmospheric Model ◽  
Surface Fluxes ◽  
Earth System ◽  
Subgrid Scale ◽  
Effective Parameters ◽  
Max Planck ◽  
Near Surface ◽  
Horizontal Length

Abstract In present-day Earth system models, the coupling of land surface and atmosphere is based on simplistic assumptions. Often the heterogeneous land surface is represented by a set of effective parameters valid for an entire model grid box. Other models assume that the surface fluxes become horizontally homogeneous at the lowest atmospheric model level. For heterogeneity above a certain horizontal length scale this is not the case, resulting in spatial subgrid-scale variability in the fluxes and in the state of the atmosphere. The Max Planck Institute for Meteorology’s Earth System Model is used with three different coupling schemes to assess the importance of the representation of spatial heterogeneity at the land surface as well as within the atmosphere. Simulations show that the land surface–atmosphere coupling distinctly influences the simulated near-surface processes with respect to different land-cover types. The representation of heterogeneity also has a distinct impact on the simulated gridbox mean state and fluxes in a large fraction of land surface.

scholarly journals Assessing Surface Solar Radiation Fluxes in the CMIP Ensembles

2016 ◽  
Vol 29 (20) ◽  
pp. 7231-7246 ◽  
Author(s):  
Alexander Loew ◽  
Axel Andersson ◽  
Jörg Trentmann ◽  
Marc Schröder
Keyword(s):  
Solar Radiation ◽  
System Modeling ◽  
Major Influence ◽  
Earth System ◽  
Surface Solar Radiation ◽  
Near Surface ◽  
System Models ◽  
Radiation Fluxes ◽  
Model Ranking ◽  
Earth System Models

Abstract Earth system models are indispensable tools in climate studies. The Coupled Model Intercomparison Project (CMIP) is a coordinated effort of the Earth system modeling community to intercompare existing models. An accurate simulation of surface solar radiation fluxes is of major importance for the accuracy of simulations of the near-surface climate in Earth system models. The present study provides a quantitative assessment of the accuracy and multidecadal changes of surface solar radiation fluxes for model results from two phases of CMIP. The entire archives of phase 5 of CMIP (CMIP5) and its predecessor phase 3 (CMIP3) are analyzed for present-day climate conditions. A relative model ranking is provided, and its uncertainty is quantified using different global observational records. It is shown that the choice of an observational dataset can have a major influence on relative model ranking between CMIP models. However the multidecadal variability of surface solar radiation fluxes, also known as global “dimming” or “brightening,” is largely underestimated by the CMIP models.

Modeling of Subgrid-Scale Mixing in Large-Eddy Simulation of Shallow Convection

2009 ◽  
Vol 66 (7) ◽  
pp. 2125-2133 ◽  
Author(s):  
Dorota Jarecka ◽  
Wojciech W. Grabowski ◽  
Hanna Pawlowska
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Cloud Water ◽  
Water Evaporation ◽  
Subgrid Scale ◽  
Cloud Environment ◽  
Shallow Convection ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Original Approach

Abstract This paper discusses an extension of the approach proposed previously to represent the delay of cloud water evaporation and buoyancy reversal due to the cloud–environment mixing in bulk microphysics large-eddy simulation of clouds. In the original approach, an additional equation for the mean spatial scale of cloudy filaments was introduced to represent the progress toward microscale homogenization of a volume undergoing turbulent cloud–environment mixing, with the evaporation of cloud water allowed only when the filament scale approached the Kolmogorov microscale. Here, it is shown through a posteriori analysis of model simulations that one should also predict the volume fraction of the cloudy air that was diagnosed in the original approach. The resulting model of turbulent mixing and homogenization, referred to as the λ–β model, is applied in a series of shallow convection simulations using various spatial resolutions and compared to the traditional bulk model. This work represents an intermediate step in the development of a modeling framework to simulate characteristics of microphysical transformations during entrainment and subgrid-scale turbulent mixing.

Subgrid-scale models for large-eddy simulations of compressible wall bounded flows

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1340-1350 ◽  
Author(s):  
E. Lenormand ◽  
P. Sagaut ◽  
L. Ta Phuoc ◽  
P. Comte
Keyword(s):  
Large Eddy Simulations ◽  
Subgrid Scale ◽  
Scale Models ◽  
Large Eddy ◽  
Wall Bounded Flows

scholarly journals Modeling microphysical effects of entrainment in clouds observed during EUCAARI-IMPACT field campaign

2013 ◽  
Vol 13 (16) ◽  
pp. 8489-8503 ◽  
Author(s):  
D. Jarecka ◽  
H. Pawlowska ◽  
W. W. Grabowski ◽  
A. A. Wyszogrodzki
Keyword(s):  
Boundary Layer ◽  
Turbulent Mixing ◽  
Marine Boundary Layer ◽  
Cloud Droplet ◽  
Droplet Radius ◽  
Subgrid Scale ◽  
Microphysics Scheme ◽  
Local Conditions ◽  
Field Campaign ◽  
Les Model

Abstract. This paper discusses aircraft observations and large-eddy simulation (LES) modeling of 15 May 2008, North Sea boundary-layer clouds from the EUCAARI-IMPACT field campaign. These clouds are advected from the northeast by the prevailing lower-tropospheric winds and featured stratocumulus-over-cumulus cloud formations. An almost-solid stratocumulus deck in the upper part of the relatively deep, weakly decoupled marine boundary layer overlays a field of small cumuli. The two cloud formations have distinct microphysical characteristics that are in general agreement with numerous past observations of strongly diluted shallow cumuli on one hand and solid marine stratocumulus on the other. Based on the available observations, a LES model setup is developed and applied in simulations using a novel LES model. The model features a double-moment warm-rain bulk microphysics scheme combined with a sophisticated subgrid-scale scheme allowing local prediction of the homogeneity of the subgrid-scale turbulent mixing. The homogeneity depends on the characteristic time scales for the droplet evaporation and for the turbulent homogenization. In the model, these scales are derived locally based on the subgrid-scale turbulent kinetic energy, spatial scale of cloudy filaments, mean cloud droplet radius, and humidity of the cloud-free air entrained into a cloud, all predicted by the LES model. The model reproduces contrasting macrophysical and microphysical characteristics of the cumulus and stratocumulus cloud layers. Simulated subgrid-scale turbulent mixing within the cumulus layer and near the stratocumulus top is on average quite inhomogeneous, but varies significantly depending on the local conditions.

scholarly journals Comparisons of Subgrid-Scale Models for OpenFoam Large- Eddy Simulation

2021 ◽  
Vol 1802 (4) ◽  
pp. 042088
Author(s):  
Zhipeng Feng ◽  
Huanhuan Qi ◽  
Xuan Huang ◽  
Shuai Liu ◽  
Jian Liu
Keyword(s):  
Large Eddy Simulation ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Scale Models ◽  
Large Eddy
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