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Land-Surface Models in MM5 Version 3

How to run Noah LSM

Since Version 3.6, the Oregon State University / NCEP Eta Land-Surface Model (OSU LSM) in MM5 (Chen and Dudhia 1999) has been replaced by an updated version of the model, known as the Noah LSM, which includes many improvements from NCEP, NCAR, AFWA and UCLA. Like the OSU LSM, using the Noah LSM option in MM5 requires additional inputs to initialize the model.

1. Noah LSM Requirements in Model Pre-Processing System

To use the Noah LSM option, the MM5 model requires several additional input fields. The Version 3 TERRAIN program provides an annual-mean deep soil temperature adjusted to model terrain elevation, a monthly climatological vegetation fraction, dominant soil type, and dominant vegetation type in each grid cell. All of the inputs to the TERRAIN program are provided by mesouser.

The REGRID program provides soil moisture, soil temperature at various depths, water-equivalent snow depth, sea ice, and optionally canopy moisture and soil water content. These additional fields are currently available from the NCEP/NCAR Reanalysis (NNRP, 2.5 degree resolution over past 40 more years), NCEP's global Final Analyses (FNL, 1.0 degree resolution since Sept 1999) and the Eta AWIP analyses (for the Continental US only, about 40 km resolution since May 1995). These datasets are archived at NCAR. The additional soil data are also available in real-time from NCEP's ftp site from Eta and AVN model outputs (ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/), or from AFWA-produced AGRMET data (http://www2.mmm.ucar.edu/mm5/doc.html). These input data are illustrated in Fig. D-1.

Two additional types of input can be ingested in the REGRID/regridder program as well: 1-degree global maximum snow albedo, and 0.15-degree monthly climatological (snow-free) albedo. The recommendation is to use the maximum snow albedo (which is used in the Noah LSM to limit values of albedo when snow is present), and use the climatological albedo with caution (for example, one may want to only use this field when the grid size is above the data resolution which is about 16 km). These two datasets are provided by mesouser. The maximum snow albedo data are provided in REGRID tar file (REGRID/regridder/ALMX_FILE), and one can obtain monthly albedo from:

ftp://ftp.ucar.edu/mesouser/MM5V3/REGRID_DATA/MONTHLY_ALBEDO.TAR.gz

or on MSS:

/MESOUSER/DATASETS/REGRID/MONTHLY_ALBEDO.TAR.gz

All LSM fields are passed along in programs RAWINS/LITTLE_R and INTERPF.

 

 

2. How to Set Program Switches to Run LSM

Terrain -

In terrain.deck, set namelist variable

LSMDATA = .T.,

and select values 1 or 2 for VEGTYPE. e.g.,

VEGTYPE = 1,

(In V3.3 or earlier terrain.deck, select

set NewLandUseOnly = FALSE

set LandSurface = TRUE

and either

set VegType = USGS

or

set VegType = SiB

The rest of the terrain.deck is the same.)

Note that SiB data is only available for North America, but these categories corresepond to those used in the Eta model's operational LSM. However, either set can be used in MM5's version of the LSM. Also, note that the SiB classification lacks an `urban' category.

These setups will make use of the terrestrial datasets to create the following additional fields on the model grid in the TERRAIN output:

1. VEGFRCnn (nn=1,12): vegetation fraction monthly climatology
2. TEMPGRD: annual mean ground temp adjusted to model terrain elevation
3. SOILINDX: dominant soil type (currently 30" over US, 5-minutes elsewhere)

Note, for soil types, one may choose either soil type data over top layer (0 - 30 cm), or bottom layer (30 - 100 cm). Selecting the bottom soil data can be done by uncommenting the script variable BotSoil near the top of terrain.deck. A comparison of top and bottom soil types over the continental US may be found online at http://www2.mmm.ucar.edu/mm5/mm5v3/new-soil.html.

REGRID -

The datasets that have the required additional fields to run Noah LSM in MM5 are Eta (AWIP or Eta212 grid), NNRP and NCEP's FNL data archived at NCAR (DSS609.2, DSS090.0, and DSS083.2, respectively). Real-time data from NCEP's Eta and AVN can also be used.

To get the NNRP data from NCAR archive, use either get_nnrp.deck.ibm for batch IBM job, or get_nnrp.csh for running interactively from pregrid/nnrp directory.

To get the FNL data from NCAR archive, go to http://dss.ucar.edu/datasets/ds083.2/inventories/, and download individual files as needed.

There isn't a deck or script to get NCAR archived AWIP data at this time. But you can do the following to obtain the data (Note that the Eta dataset only covers Continental US. It starts May 1995, and may have missing periods):

1. Use Web browser to go to

   ftp://ncardata.ucar.edu/datasets/ds609.2/inventories/eta.inv

and find out which Gxxxxx file contains the time period of your interest. Should get both 3Danal and SFanal files.

2. On NCAR's computer, type the following to get the dataset in non-cos-blocked format:

   msread -fBI Gxxxxx /DSS/Gxxxxx

(You may then ftp this file back to your local workstation to do the rest. Note though these files are very BIG in size: the 3Danal file is about 1Gb each, and SFanal is about 250 mb. If ftping big file is a problem, do steps 3 and 4 on Cray, and ftp the files after step 4.)

3. Type the following to obtain all file listed in the Gxxxxx file:

   tar tvf Gxxxxx > tar.list

Or find out the files from

   ftp://ncardata.ucar.edu/datasets/ds609.2/inventories/TARLIST

and click on the appropriate tarlist file.

4. Extract the tmXX files to use by typing, using G40001 (containing upperair data) and G40006 (containing surface data) files as an example:

    tar -xvf G40001 9706_3Danal/97062400.AWIP3D00.tm00
and
    tar -xvf G40006 9706_SFanal/97062400.AWIPSF00.tm00

Repeat the last two commands several times to obtain all time periods. The tm00 files are to be used by pregrid program. (If one wants to use other tmXX files, please refer to the DSS document at http://dss.ucar.edu/datasets/ds609.2/docs/awip212.html.) The extracted file for each time period is considerably smaller in file size: about 5 Mb each for upperair data and 1.2 Mb for surface data. You can ftp each file back to your workstation, or tar them up and then ftp the file back. Note, if you would like to run REGRID on NCAR's IBM using AWIP dataset, you can either run the job interactively if your domain size is not too big (IBM allows for 32 Mb of memory for interactive job only), or you can modify the deck to extract the files only.

In pregrid.csh make sure you have either Eta (AWIP or Eta212 grid), or NNRP, or FNL data for the relevant dates, set SRCSOIL to either $SRC3D or different input files, and:

   set VTSOIL = ../grib.misc/Vtable.AWIPSOIL
or
   set VTSOIL = ../grib.misc/Vtable.NNRPSOIL
or
   set VTSOIL = ../grib.misc/Vtable.AVNSOIL

For snow data, you will need to set SRCSNOW for input files and use one of the Vtable file for VTSNOW (Vtable.AWIPSNOW, or Vtable.NNRPSNOW, or Vtable.AVNSNOW).

If you have other LSM data, check the Vtables above to see which fields that may be used. The fields added to the standard meteorological fields by setting SRCSOIL (and SRCSNOW) are:

1. SOILTnnn: Soil temp at various depths (nnn are in cm; unit: K)
2. SOILMnnn: Soil moisture at various depths (nnn are in cm; unit: fraction)
3. SOILHGT: Analysis surface elevation, used in REGRID to adjust soil temp (unit: m)
4. WEASD: Water-equivalent snow depth (optional but highly desirable; unit: kg m{-2})
5. SEAICE: Sea-ice mask (optional but highly desirable; 0 or 1)
6. SOILWnnn: Soil water (optional and currently from AGRMET only; unit: m3/m3)

where nnn is equal to 010, 040, 100 and 200 (10, 40, 100 and 200 cm, respectively) for various datasets we support. Among these fields, only the soil temperature, soil moisture, and soil height fields are required by the Noah LSM option. But we recommend that fields WEASD and SEAICE are made available. If your LSM data contain fields at levels other than those listed, you can still use them. For example, you may get soil temperature at 10 and 200 cm only, or perhaps at other levels, you can modify Vtable to extract these fields. When you run MM5, you can use the namelist options ISTLYR and ISMLYR (available since V3-2) to define where your data are (see below).

Since V3.6, REGRID may ingest AGRMET LSM data. This dataset is produced by AFWA, and made available to MM5 users since October 2002 (with two months delay in real-time). The data are archived at NCAR on MSS: /MESOUSER/DATASETS/AGRMET/. Vtables for this dataset are provided in REGRID/pregrid/grib.misc/Vtable.AGRMETxxxx. Soil temperature, moisture, water, landsea mask and soil height fields are extracted from this dataset. One may use this dataset in combination with other three-dimensional meteorological input.

In regridder, do not use sst_to_ice_threshold in the namelist.input, i.e. do not turn sea water into land ice. Use the SEAICE field in the input instead.

MM5 -

To use the Noah LSM, set ISOIL=2 in configure.user prior to compilation. IBLTYP=4 or 5 (the Eta or MRF PBL) must be used for now. They are the only ones coupled to the LSM.

If you have ingested climatological albedo fields from REGRID, you may choose to use or not use them in MM5. Set the following namelist variables to .FALSE. if you don't want to use them in the model:

   RDMAXALB = .FALSE.,
   RDBRDALB = .FALSE.,

We generally recommend that one uses the climatological maximum snow albedo only.

To use input soil temperature and moisture at levels other than the default, one can add namelist variables ISTLYR and ISMLYR in the namelist LPARAM section to specify these levels. For example,

   ISTLYR = 10,200,0,0,
   ISMLYR = 10,200,0,0,

TThis shows that the input soil temperature only comes in at 10 and 200 cm levels. Note that one can only input up to 4 levels of soil temperature and moisture. The prediction levels in current MM5/Noah LSM are 5, 25, 70, and 150 cm and are bounded between surface and 300 cm below. The climatological deep soil temperature generated in program TERRAIN is used as the lower boundary condition for the Noah LSM, while open-boundary condition is used for soil moisture and soil water.

Additional Noah LSM prognostic outputs from MM5 are:

1. SOIL Tn (n=1,4): The soil temp at all 4 soil levels, unit K;
2. SOIL Mn (n=1,4): The soil moisture at all 4 soil levels, unit m3/m3;
3. SOIL Wn (n=1,4): The soil water at all 4 soil levels, unit m3/m3;
4. CANOPYM: Canopy moisture, unit m;
5. SNOWH: Snow height, unit m;
6. WEASD: Water equivalent snow depth, unit mm;
7. SFCRNOFF: Surface runoff accumulation, unit mm;
8. UGDRNOFF: Underground runoff accumulation, unit mm;
9. GRNFLX: Ground head flux, unit W m-2;
10. ALB: Albedo, unit fraction.

Note 1: If using NNRP soil moisture, you may want to check init.F and initnest.F, where there is a correction for some known biases in soil moisture. Comment out GOTO 1001, and GOTO 2001 in those routines respectively, if you want to use this correction.

Note 2: If you want diagnostic LSM prints at a gridpoint, change the line in surfce.F (SURFCE.284) to NOOUT=1 and edit the IF statements determining where and how often to output data.

Note 3: When using NESTDOWN to generate input files for a one-way nested run, again make sure that one doesn't use the sst_to_ice_threshold option, and check interpolated fields (especially those of masked fields: e.g. sea ice, snow height, soil water, and other LSM fields) carefully.

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