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UFS-SRW v3.0.0 SciDoc updates #91
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/** | ||
\page CLM_LAKE_model CLM Lake Model | ||
\section des_clmlake Description | ||
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The Community Land Model (CLM) lake model is a multi-level one-dimensional lake model that has been implemented within the operational 3-km HRRR and | ||
13-km RAP for small lakes (Benjamin et al. (2022) \cite gmd-15-6659-2022). It is the Community Land Model, version 4.5. | ||
Subin et al. (2012) \cite Subin_2012 describe the 1-d CLM lake model as applied within the Community Earth System | ||
Model (CESM) as a component of the overall CESM CLM (Lawrence et al. (2019) \cite Lawrence_2019). Gu et al. (2015) \cite Gu2015 | ||
describe the introduction of the CLM lake model into the WRF model and inital experiments using its 1-d solution for both | ||
lakes Superior (average depth of 147 m) and Erie (average depth of 19 m). | ||
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The atmospheric inputs into the model are temperature, water vapor, horizontal wind components from the lowest atmospheric level | ||
and short-wave and longwave radiative fluxes. The CLM lake model then provides latent heat and sensible heat fluxes back to the | ||
atmosphere. It also computes 2-m temperature/moisture, skin temperature, lake temperature, ice fraction, ice thickness, snow water | ||
equivalent and snow depth. The CLM lake model divides the vertical lake profile into 10 layers driven by wind-driven eddies. The | ||
thickness of the top layer is fixed to 10-cm and the rest of the lake depth is divided evenly into the other 9 layers. Energy | ||
transfer (heat and kinetic energy) occurs between lake layers via eddy and molecular diffusion as a function of the vertical | ||
temperature gradient. The CLM lake model also uses a 10-layer soil model beneath the lake, a multi-layer ice formation model and | ||
up to 5-layer snow-on-ice model. Multiple layers in lake model have the potential to better represent vertical mixing processes | ||
in the lake. | ||
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Testing of the CLM lake model within RAP/HRRR applications showed computational efficiency of the model with no change of even | ||
0.1% in run time. The lake/snow variables have to be continuously transfered within the CLM lake model from one forecast to another, | ||
constrained by the atmospheric data assimilation. The lake-cycling initialization in RAP/HRRR has been effective overall, owing to | ||
accurate houly estimates of near-surface temperature, moisture and winds, and shortwave and longwave estimates provided to the 1-d CLM | ||
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lake model every time step (Benjamin et al. (2022) \cite gmd-15-6659-2022). Cycling technique showed improvements over initializing | ||
lake temperatures from the SST analysis, problematic for small water bodies. The improvements are particularly eminent during transition | ||
periods between cold and warm seasons, and in the regions with anomalies in weather conditions. The CLM lake model has the potential | ||
to improve surface prediction in the vicinity of small lakes. | ||
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The CLM lake model requires bathymetry for the lake points in the model domain. Grid points are assigned as lake points when the | ||
fraction of lake coverage in the grid cell exceeds 50% and when this point is disconnected from oceans. The lake water mask is | ||
therefore binary, set to either 1 or 0. This binary approach for models with higher horizontal resolution, for example, 3-km resolution in | ||
in the UFS SRW App, is capable of capturing the effect of lakes on regional heat and moisture fluxes. | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. @ligiabernardet Your comment "in the regional application of UFS (RRFS) -> in the UFS SRW App" is addressed here. |
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Lake depths for the RRFS lake configuration (Fig.1) are assigned from a global dataset provided by Kourzeneva et al.(2012) \cite Kourzeneva_2012, | ||
this dataset is referred to as GLOBv3 bathymetry in the UFS_UTL. | ||
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@image html https://user-images.githubusercontent.com/12705538/250180794-76af93a2-a7ba-4e9a-9478-5657198862b8.png "Figure 1: Lake depths for lakes in the 3-km RRFS domain." width=600 | ||
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To cold-start the CLM lake model in the UFS SRW App: | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. @ligiabernardet Your comment "To cold-start the CLM lake model in RRFS -. To cold-start the CLM lake model in the UFS SRW App" is addressed here. |
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- Use the CLM option in the input.nml | ||
\n - lkm = 1 | ||
\n - iopt_lake = 2 | ||
- Lake temperature is initialized from interpolation between SST at the surface and \f$-4^oC\f$ at 50-m depth | ||
\n - A special case is for the Great Salt Lake, the temperature is limited with +/- 3 K from the bi-weekly climatology | ||
- Temperature for soil under the lake is initialized from bottom lake temperature at the top to the substrate soil temperature at the bottom of soil layer | ||
- Lake ice at the top level is initialized from the GFS ice concentration | ||
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The differences of surface variables from the experimental RRFS 6-h forecast with/without CLM lake model are shown in Figure 2 for 2-m temperature and in Figure 3 for 2-m dewpoint. | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. @ligiabernardet Your comment "The differences of surface variables from the RRFS 6-h forecast -> The differences of surface variables from the experimental RRFS 6-h forecast" is addressed here. |
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@image html https://user-images.githubusercontent.com/12705538/250180790-63159300-33f6-4b34-9e9c-b65885213c30.png "Figure 2: Differences of 2-m temperature between the RRFS coupled to the CLM model and the RRFS without CLM." width=600 | ||
@image html https://user-images.githubusercontent.com/12705538/250180787-8fc9a820-5f80-4f06-b50a-88b2d20ebc53.png "Figure 3: Differences of 2-m dew point between the RRFS coupled to the CLM model and the RRFS without CLM." width=600 | ||
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\section intra_clmlake Intraphysics Communication | ||
- \ref arg_table_clm_lake_run | ||
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*/ |
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@ligiabernardet Regarding your comment "It also computes 2-m temperature: Of the air?? That is surprising to me.", I see Man leaves it as is. I guess the reason for this is because CLM works like a land surface model but over lake grid points, where it would calculate those 2-m diagnostics based on M-O similarity theory (https://www2.cesm.ucar.edu/models/cesm2/land/CLM50_Tech_Note.pdf, ~Page 48).