3.2. Input/Output Files for the Land DA System 

This chapter provides practical information on input and output files and parameters for the Land DA System, including the UFS Weather Model, its Noah-MP Land Surface Model (LSM) component, and the JEDI data assimilation (DA) system.

3.2.1. Data Overview 

The Land DA System requires the following files for each case/configuration:

For all cases:

NOAH-MP initial conditions (ICs) files

FV3 fix files (tiled)

JEDI input fix files

Observation data files (IMS, GHCN, SMAP, SMOPS)

Cartopy Natural Earth files (only if running the plotting task)

For LND cases:

Forcing files (ERA5 or GSWP3)

For ATML cases:

FV3 fix files (global)

For coldstart cases:

Model output from a previous model run (e.g., from GDAS, GFS, SMAP, or SMOPS).

For warmstart cases:

Restart files from a model run starting the cycle before the user’s selected date (e.g., RESTART files from a WM run)

These files will be described in more detail throughout this chapter. Users can download many of these files from the Land DA data bucket using the instructions provided in the next section.

3.2.1.1. Data for Sample Cases 

The Land DA data bucket contains input files required for cases described in the Land DA System documentation. These files are publicly available, and users can download the data and untar the files via the command line using wget (or via the Amazon Web Services [AWS] Command Line Interface [CLI]):

wget https://noaa-ufs-land-da-pds.s3.amazonaws.com/current_land_da_release_data/v3.0.0/LandDAInputDatav3.0.0.tar.gz
tar xvfz LandDAInputDatav3.0.0.tar.gz

These files and their parameters are described in the following subsections. Although this download provides all files needed to run the provided sample cases, users wishing to configure their own cases will need to read Section 3.2.2 to determine what additional data they may need to download and where to find it.

3.2.1.2. Obtaining Data for User-Defined Cases 

In theory, users can run the Land DA System for dates other than the sample cases provided. This is not yet a supported feature, but users are welcome to try it after running the provided sample cases successfully. However, user-defined cases may require significant troubleshooting. Users may reach out through GitHub Discussions Q & A, and the Land DA development team will assist as time allows. The data descriptions throughout this chapter provide suggestions for how to obtain the various data required for different components of the Land DA System.

3.2.2. Input Files 

3.2.2.1. Data Applicable to All Land DA Configurations 

The Noah-MP LSM requires multiple input files to run, including static datasets (fix files containing climatological information, terrain, and land use data) and initial conditions files. Users may reference the Community Noah-MP Land Surface Modeling System Technical Description Version 5.0 (2023) for a detailed technical description of certain elements of the Noah-MP model.

In Noah-MP, the tiled fix file(s) and initial conditions file(s) specify model parameters. These files are required for all configurations of the Land DA System. Additionally, the DA system requires JEDI fix files and observations as input. If users intend to perform plotting tasks, Cartopy Natural Earth files are also necessary.

3.2.2.1.1. Noah-MP Initial Conditions 

Required for: All Land DA cases

The initial conditions files include the initial state variables that are required for the UFS land snow DA to begin a cycling run. The data must be provided in netCDF format.

By default, on Level 1 systems and in the Land DA data bucket, the initial conditions files are located at inputs/NOAHMP_IC/ufs-land_C96_init_fields.tile*.nc (downloaded in Section 3.2.1.1). Each file corresponds to one of the six tiles of the global FV3 grid.

The files contain the following data:

Table 3.2 Variables specified in the initial conditions files `ufs-land_C96_init_fields.tile*.nc`
Variables	Long Name	Units
time(time)	“time”	“seconds since 1970-01-01 00:00:00”
geolat(lat, lon)	“latitude”	“degrees_north”
geolon(lat, lon)	“longitude”	“degrees_east”
snow_water_equivalent(time, lat, lon)	“snow water equivalent”	“mm”
snow_depth(time, lat, lon)	“snow depth”	“m”
canopy_water(time, lat, lon)	“canopy surface water”	“mm”
skin_temperature(time, lat, lon)	“surface skin temperature”	“K”
soil_temperature(time, soil_levels, lat, lon)	“soil temperature”	“K”
soil_moisture(time, soil_levels, lat, lon)	“volumetric soil moisture”	“m3/m3”
soil_liquid(time, soil_levels, lat, lon)	“volumetric soil liquid”	“m3/m3”

The full Land DA data bucket download (see Section 3.2.1.1) includes ICs for Land DA in the inputs/NOAHMP_IC directory. These are essentially dummy ICs that can be used with LND and warmstart ATML cases. For ATML coldstart cases, the fcst_ic task will generate the ICs by running the model for one cycle before performing DA, and users need not worry about staging ICs. For LND or ATML warmstart cases, ICs must be provided. Users can use the ICs from the inputs/NOAHMP_IC directory (downloaded from the data bucket) for any case. In theory, users can also choose to use/produce their own ICs, either by running the ATML coldstart case for the cycle before the desired date or by generating them from the GDAS results. However, this is not yet supported functionality for the Land DA System.

3.2.2.1.2. FV3_fix_tiled Files 

Required for: All Land DA cases (currently supported only for C96 resolution)

The UFS land component also requires a series of tiled static (fix) files that will be used by the component model. These files are resolution-dependent and contain information on maximum snow albedo, slope type, soil color and type, substrate temperature, vegetation greenness and type, and orography (grid and land mask information). These files are located in the inputs/FV3_fix_tiled/C96 directory (downloaded in Section 3.2.1.1). They should be used even for user-defined cases, since they do not change from case to case.

C96.facsf.tile*.nc
C96_grid.tile*.nc
C96.maximum_snow_albedo.tile*.nc
C96.slope_type.tile*.nc
C96.snowfree_albedo.tile*.nc
C96.soil_color.tile*.nc
C96.soil_type.tile*.nc
C96.substrate_temperature.tile*.nc
C96.vegetation_greenness.tile*.nc
C96.vegetation_type.tile*.nc
C96_oro_data.tile*.nc
C96_oro_data_ss.tile*.nc
C96_oro_data_ls.tile*.nc
C96_grid_spec.nc
C96_mosaic.nc

The C96_grid.tile*.nc files contain grid information for tiles 1-6 at C96 grid resolution and were formerly named oro_Cxx.mx100.tile*.nc (where mx100 refers to the ocean resolution (100=1º)). The C96_grid_spec.nc file contains information on the mosaic grid.

Note

The C96_grid_spec.nc and C96_mosaic.nc files are the same file under different names and may be used interchangeably.

Note

The inputs data directory also contains data for C192 and C384 resolution, but running at these higher resolutions is currently unsupported functionality.

3.2.2.1.3. Fixed JEDI Input Files 

Required for: All Land DA cases

The JEDI DA component of the Land DA System requires several fixed fv3files files as input. Most of these files are used by the JEDI Geometry class.

The fv3files include:

ak/bk values
field tables
namelist files

These files are explained in detail in the JEDI fv3files documentation. They are available in the inputs/DATA_jedi_input/fv3files directory (downloaded in Section 3.2.1.1).

3.2.2.1.4. Observation Data 

Required for: All Land DA cases

The Land DA System can accept GHCN, IMS, and SFCSNO snow observation data. It accepts SMAP or SMOPS soil moisture observation data. Users need only provide one type of observation data depending on whether they plan to perform snow or soil moisture data assimilation.

Currently, snow observation data is primarily drawn from the Global Historical Climatology Network (GHCN) and the U.S. National Ice Center (USNIC) Interactive Multisensor Snow and Ice Mapping System (IMS). GHCN and IMS data for provided sample cases are available in the inputs/DA_obs directory. These data are converted to IODA format in the prep_data task.

Soil moisture data is primarily drawn from the National Snow and Ice Data Center Soil Moisture Active Passive (SMAP) data set or from the NOAA Soil Moisture Operational Products System (SMOPS) data set. SMAP and SMOPS data for provided sample cases are available in the inputs/DATA_[smap|smops] directories. These data are converted to IODA format in the prep_data task.

In each experiment, the land_analysis.yaml file sets the type(s) of observation files to be used in the experiment via the OBS_*_SNOW variables (based on selections in config.yaml). Before assimilation, the files for the specified observation type are copied to the run directory (usually ${BASEDIR}/ptmp/<envir>/com/landda/${model_ver}/landda.${PDY}${cyc}/obs by default — see Section 3.1.3.1 for more on these variables), sometimes with a naming-convention change (e.g., ghcn_snwd_ioda_${YYYY}${MM}${DD}.nc to ghcn_snow_${YYYY}${MM}${DD}${HH}.nc).

3.2.2.1.4.1. GHCN Snow Depth Files 

Snow depth observations can be taken from the Global Historical Climatology Network (GHCN), which provides daily climate summaries sourced from a global network of 100,000 stations. NOAA’s NCEI provides access to these snow depth and snowfall measurements through daily-generated individual station ASCII files or GZipped tar files of full-network observations on the NCEI server or Climate Data Online. Alternatively, users may acquire yearly tarballs via wget:

wget https://www1.ncdc.noaa.gov/pub/data/ghcn/daily/by_year/{YYYY}.csv.gz

where ${YYYY} is replaced with the year of interest. Note that these yearly tarballs contain all measurement types from the daily GHCN output, and thus, snow depth must be manually extracted from this broader data set.

These raw snow depth observations need to be converted into IODA-formatted netCDF files for ingestion into the JEDI DA system. This process is handled in the prep_data task using the ush/ghcn_snod2ioda.py utility script.

A selection of GHCN files is available in the inputs/DA_obs/GHCN/${YEAR} directories. The primary observation variable is totalSnowDepth, which, along with the metadata fields of datetime, latitude, longitude, stationElevation, and stationIdentification is defined along the nlocs dimension. Also present are ObsError, ObsValue, and PreQC values corresponding to each totalSnowDepth measurement on nlocs. The magnitude of nlocs varies between files; this is due to the fact that the number of stations reporting snow depth observations for a given day can vary in the GHCN.

GHCN files for 2000, 2011, and 2025 are already provided in IODA format for the v3.0.0 release. Table 2.1.4.2.1 indicates where users can find data on NOAA RDHPCS platforms. Tar files containing the data are located in the publicly-available Land DA Data Bucket. Once untarred, the snow depth files are located in inputs/DA_obs/GHCN/${YEAR}. Each file follows the naming convention of ghcn_snwd_ioda_${YYYY}${MM}${DD}.nc, where ${YYYY} is the four-digit cycle year, ${MM} is the two-digit cycle month, and ${DD} is the two-digit cycle day.

3.2.2.1.4.2. IMS Snow Depth Files 

The Interactive Multisensor Snow and Ice Mapping System (IMS) is an “operational software package used to demarcate the presence of snow and ice across the entire northern hemisphere.” It produces daily 4-km resolution maps of snow and ice in the Northern Hemisphere; these maps are distributed by the U.S. National Ice Center. Files are available in compressed ASCII format. Users can download these files from the U.S. National Ice Center Archive.

These raw snow depth observations need to be converted into IODA-formatted netCDF files for ingestion into the JEDI system. This process is handled in the prep_data task. First, the ASCII files are processed for the UFS model grid using the sorc/calcfIMS.fd executable, and then the output is converted into IODA format using the ush/ghcn_snod2ioda.py utility script.

Note

When the IMS option is turned on, SFCSNO files are also added because IMS data alone does not produce satisfactory results compared to GHCN data (see GitHub Issue #223 and PR #224).

3.2.2.1.4.3. SFCSNO Files 

SFCSNO files are Global Telecommunication System (GTS) data from GDAS/GFS. GTS is “[t]he co-ordinated global system of telecommunication facilities and arrangements for the rapid collection, exchange and distribution of observations and processed information within the framework of the World Weather Watch.” SFCSNO files are already provided in BUFR format in the usual locations on NOAA RDHPCS platforms and in the publicly-available Land DA Data Bucket. In both cases, they are located in the inputs/DATA_gdas directory (downloaded above from the data bucket). Each file is named gdas.t00z.sfcsno.tm00.bufr_d and is located under the relevant cycle date (e.g., inputs/DATA_gdas/20250119/gdas.t00z.sfcsno.tm00.bufr_d). IODA can read BUFR files when provided with an appropriate mapping file, such as the parm/jedi/bufr_sfcsno_mapping.yaml in the Land DA repository. The jedi_<algorithm>_snow.yaml file produced by the jcb task contains information on observations, including the IODA “engine” used to read the file (bufr for BUFR files) and the path to the “mapping file.” For example:

observations:
  obs perturbations: false
  observers:
  - obs space:
    name: sfcsno
    obsdatain:
      engine:
        type: bufr
        obsfile: obs/obs.20250119.t00z.sfcsno.tm00.bufr_d
        mapping file: obs/bufr_sfcsno_mapping.yaml
        missing file action: warn
    obsdataout:
      engine:
        type: H5File
        obsfile: diags/diag.sfcsno_2025011900.nc
    simulated variables:
    - totalSnowDepth

3.2.2.1.4.4. SMAP Soil Moisture Files 

Soil Moisture Active Passive (SMAP) data “includes data products derived from an L-band radiometer and high-resolution L-band radar instrument that make up the orbiting observatory of the Soil Moisture Active Passive (SMAP) satellite mission.” Observations for Land DA sample cases are available in the inputs/DATA_smap directory (downloaded in Section 3.2.1.1). The ush directory contains two utility scripts that will be used by the prep_data task to convert SMAP soil moisture data to IODA format: smap_ioda_concat_files.py and smap_ssm2ioda.py.

Users can download additional observation data for specific dates of choice (31 March 2015 to present) from the National Snow and Ice Data Center. There are several ways to download this data, but these instructions will explain how to download via browser/HTTPS from the NASA Earthdata website.

Before getting started, create a NASA Earthdata Login (EDL) at https://urs.earthdata.nasa.gov/.
Navigate to the Earthdata page containing data for the “SMAP Enhanced L2 Radiometer half-Orbit 9km EASE-Grid Soil Moisture, Version 6” (SPL2SMP_E) data set: https://cmr.earthdata.nasa.gov/virtual-directory/collections/C2938663676-NSIDC_CPRD/temporal.
Search for the desired files by clicking through the appropriate year, month, and day links.
Download all files for a given day by clicking to download.

For additional download options, visit the NSIDC NASA Earthdata Cloud Data Access Guide.

3.2.2.1.4.5. SMOPS Soil Moisture Files 

The Soil Moisture Operational Products System (SMOPS) “combines soil moisture retrievals from multi-satellites/sensors to provide a global soil moisture map with more spatial and temporal coverage.” Observations for Land DA sample cases are available in the inputs/DATA_smops directory (downloaded in Section 3.2.1.1). However, users can download additional observation data for specific dates of choice from the National Environmental Satellite, Data, and Information Service (NESDIS) by navigating to the NESDIS STAR file share and selecting/downloading data for those dates.

3.2.2.1.5. Cartopy Natural Earth Files 

The set of Natural Earth raster files and shapefiles required for Land DA System plotting tasks is available in the inputs/NaturalEarth directory (downloaded in Section 3.2.1.1). The full set of Natural Earth shapefiles can also be downloaded from the Natural Earth website.

3.2.2.2. Data Required for LND Configurations Only

Required for: LND configurations (Noah-MP + DATM)

When the NOAH-MP land component is used without an active atmospheric component, atmospheric forcing files must be provided for the data atmosphere (DATM) component. Currently, users can choose between ERA5 atmospheric forcing data or GSWP3 atmospheric forcing data.

Several pre-configured LND cases are available in the Land DA repository:

Table 3.3 Preconfigured LND Cases
File Name	Data Forcing	JEDI Algorithm	Observation Data	Start Type	DATE_FIRST_CYCLE	Number of 24-hr Cycles
config.LND.era5.3dvar.ims.DA-fcst.warmstart.yaml	ERA5	3dvar	IMS	warm	2025-01-19 00z	2
config.LND.era5.letkfoi.ghcn.DA-fcst.coldstart.yaml	ERA5	letkf-oi	GHCN	cold	2025-01-17 00z	2
config.LND.era5.letkfoi.smap.free-fcst.warmstart.yaml	ERA5	letkf-oi	SMAP	warm	2025-01-19 00z	1
config.LND.gswp3.3dvar.ghcn.DA-fcst.coldstart.yaml	GSWP3	3dvar	GHCN	cold	2000-01-30 00z	3
config.LND.gswp3.letkfoi.ghcn.DA-fcst.warmstart.yaml	GSWP3	letkf-oi	GHCN	warm	2000-02-02 00z	2
config.LND.era5.letkfoi.smops.free-fcst.coldstart.yaml	ERA5	letkf-oi	SMOPS	cold	2022-12-20 00z	3

On Level 1 platforms, the requisite data are pre-staged at the locations listed in Section 2.1. The data are also publicly available via the Land DA Data Bucket.

3.2.2.2.1. GSWP3 Forcing Files 

Global Soil Wetness Project Phase 3 (GSWP3) forcing files for the LND configuration are located in the inputs/DATM_input_data/gswp3 directory (downloaded above).

clmforc.GSWP3.c2011.0.5x0.5.Prec.1999-12.nc
clmforc.GSWP3.c2011.0.5x0.5.Prec.2000-01.nc
clmforc.GSWP3.c2011.0.5x0.5.Prec.2000-02.nc
clmforc.GSWP3.c2011.0.5x0.5.Solr.1999-12.nc
clmforc.GSWP3.c2011.0.5x0.5.Solr.2000-01.nc
clmforc.GSWP3.c2011.0.5x0.5.Solr.2000-02.nc
clmforc.GSWP3.c2011.0.5x0.5.TPQWL.1999-12.nc
clmforc.GSWP3.c2011.0.5x0.5.TPQWL.2000-01.nc
clmforc.GSWP3.c2011.0.5x0.5.TPQWL.2000-02.nc
clmforc.GSWP3.c2011.0.5x0.5.TPQWL.SCRIP.210520_ESMFmesh.nc
fv1.9x2.5_141008_ESMFmesh.nc
topodata_0.9x1.25_USGS_070110_stream_c151201.nc
topodata_0.9x1.SCRIP.210520_ESMFmesh.nc

These files provide atmospheric forcing data related to precipitation, solar radiation, longwave radiation, temperature, pressure, winds, humidity, topography, and mesh data.

Formerly, this data was available a now-defunct University of Tokyo website. It may be possible to download the GSWP3 data from the Inter-Sectoral Impact Model Intercomparison Project website, but Land DA developers have not tried this method, and users download materials at their own risk.

3.2.2.2.2. ERA5 Forcing Files 

ECMWF Reanalysis v5 (ERA5) forcing files for the LND configuration are located in the inputs/DATM_input_data/era5 directory (downloaded above). They are named ERA5_forcing_YYYY-MM-DD_fix.nc. Additionally, there is an ERA5_mesh.nc file:

ERA5_forcing_2010-12-31_fix.nc
ERA5_forcing_2011-01-01_fix.nc
ERA5_forcing_2011-01-02_fix.nc
...
ERA5_forcing_2025-01-19_fix.nc
ERA5_forcing_2025-01-20_fix.nc
ERA5_forcing_2025-01-21_fix.nc
ERA5_forcing_2025-01-23_fix.nc
ERA5_mesh.nc

These files provide atmospheric forcing data related to precipitation, solar radiation, longwave radiation, temperature, surface pressure, wind speed, specific humidity, and mesh data.

3.2.2.2.2.1. ERA5 Forcing Data Downloads 

Users who wish to develop a new case using different forecast/cycling dates may download ERA5 data for free from Copernicus. First, register for an account at https://cds.climate.copernicus.eu. After creating a username and password and signing in, users can navigate to the page for ERA5 hourly data on single levels from 1940 to present. Then, select the items required for the Land DA System:

Product type:

Reanalysis

Variable:

Under Popular, select:
- 10m u-component of wind
- 10m v-component of wind
- 2m dewpoint temperature
- 2m temperature
- Surface pressure
Under Mean rates, select:
- Mean surface downward long-wave radiation flux
- Mean surface downward short-wave radiation flux
- Mean total precipitation rate

Year:

Select year(s) of the data to download.

Month:

Select month(s) of the data to download.

Day:

Select day(s) of the data to download.

Time:

Click “Select all”

Geographical area:

Whole available region

Data format:

NetCDF4

Download format:

“Unarchived” or “Zip”

Read the license and click “Accept terms”.

Once the data is downloaded, change the file names:

mv data_stream-oper_stepType-avg.nc era5_[yyyymmdd]_avg.nc
mv data_stream-oper_stepType-instant.nc era5_[yyyymmdd]_instant.nc

Move or soft link the files to the ${BASEDIR}/land-DA_workflow/fix directory for the prep_data workflow task.

3.2.2.3. Input Files for the ATML (FV3 + LND) Configuration 

Required for: ATML configuration (Noah-MP + FV3)

In the ATML configuration of the Land DA System, users run with the active FV3 atmospheric component. One Pre-configured ATML case is available in the Land DA repository:

Table 3.4 Preconfigured ATML Cases
File Name	JEDI Algorithm	Observation Data	Start Type	DATE_FIRST_CYCLE	Number of 24-hr Cycles
config.ATML.3dvar.ghcn.DA-fcst.coldstart.yaml	3dvar	IMS	cold	2022-12-21 00z	2

The FV3 component requires global fix files and FV3 initial conditions files. On Level 1 platforms, the requisite data are pre-staged at the locations listed in Section 2.1. The data are also publicly available via the Land DA Data Bucket.

3.2.2.3.1. Global Fix Files 

Required for: ATML configurations

Global fix file data for the FV3 component are required to run the ATML configurations. They are located in the inputs/FV3_fix_global directory (downloaded in Section 3.2.1.1).

aeroclim.m[01-12].nc
aerosol.dat
CCN_ACTIVATE.BIN
co2historicaldata_[2009-2024].txt
co2monthlycyc.txt
freezeH2O.dat
global_glacier.2x2.grb
global_h2oprdlos.f77
global_hyblev.l128.txt
global_maxice.2x2.grb
global_o3prdlos.f77
global_slmask.t1534.3072.1536.grb
global_snoclim.1.875.grb
global_soilmgldas.statsgo.t1534.3072.1536.grb
IMS-NIC.blended.ice.monthly.clim.grb
optics_[BC|DU|OC|SS|SU].dat
qr_acr_qsV2.dat
RTGSST.1982.2012.monthly.clim.grb
sfc_emissivity_idx.txt
snow_bump_nicas_250km_shadowlevels_nicas.nc
solarconstant_noaa_an.txt
ugwp_limb_tau.nc

Note that options in brackets indicate multiple files with similar naming conventions (e.g., aeroclim.m[01-12].nc means that there are twelve files, numbered from aeroclim.m01.nc to aeroclim.m12.nc).

3.2.2.3.2. `ATML` Input Data for Initial Conditions Generation 

Required for: ATML coldstart cases

Input data from GDAS or GFS is required to run the ATML configurations. The data are located in the inputs/DATA_[gdas|gfs] directories (downloaded above) and are used as initial conditions for the fcst_ic task. The exlandda_fcst_ic.sh script sets the default path to this data using the COMINgdas and COMINgfs variables. The operational WCOSS Implementation Standards designate COMIN* directories as directories containing input data for the model indicated in the directory name (e.g., COMINgfs contains input data for the GFS model). In addition, these directories (DATA_[gdas|gfs]) contain the IMS raw data files. Within each COMIN* directory, data is organized by cycle date. For example, for 20250119, the following data is present in the DATA_gdas/20250119 directory:

gdas.t00z.imssnow96.asc
gdas.t00z.imssnow96.grib2
gdas.t00z.sfcsno.tm00.bufr_d
gdas.t00z.snocvr.tm00.bufr_d

3.2.2.4. Restart Files 

Required for: Warmstart cases

To restart the Land DA System successfully after land model execution, all parameters, states, and fluxes used for a subsequent time iteration are stored in a restart file. This restart file is named ufs_land_restart.${FILEDATE}.tile#.nc where FILEDATE is in YYYY-MM-DD_HH-mm-SS format and # is 1-6 (e.g., ufs_land_restart.2000-01-05_00-00-00.tile1.nc). The restart file contains all the model fields and their values at a specific point in time; this information can be used to restart the model immediately to run the next cycle. The Land DA System reads the states from the restart file and replaces them after the DA step with the updated analysis. Then, this updated information is fed into the model. Table 3.5 lists the fields in the Land DA restart file.

Table 3.5 Files Included in `ufs_land_restart.{FILEDATE}.nc`
Variable	Long name	Unit
time	time	“seconds since 1970-01-01 00:00:00”
timestep	time step	“seconds”
vegetation_fraction	Vegetation fraction	“-”
emissivity_total	surface emissivity	“-”
albedo_direct_vis	surface albedo - direct visible	“-”
albedo_direct_nir	surface albedo - direct NIR	“-”
albedo_diffuse_vis	surface albedo - diffuse visible	“-”
albedo_diffuse_nir	surface albedo - diffuse NIR	“-”
temperature_soil_bot	deep soil temperature	“K”
cm_noahmp	surface exchange coefficient for momentum	“m/s”
ch_noahmp	surface exchange coefficient heat & moisture	“m/s”
forcing_height	height of forcing	“m”
max_vegetation_frac	maximum fractional coverage of vegetation	“fraction”
albedo_total	grid composite albedo	“fraction”
snow_water_equiv	snow water equivalent	“mm”
snow_depth	snow depth	“m”
temperature_radiative	surface radiative temperature	“K”
soil_moisture_vol	volumetric moisture content in soil level	“m3/m3”
temperature_soil	temperature in soil level	“K”
soil_liquid_vol	volumetric liquid content in soil level	“m3/m3”
canopy_water	canopy moisture content	“m”
transpiration_heat	plant transpiration	“W/m2”
friction_velocity	friction velocity	“m/s”
z0_total	surface roughness	“m”
snow_cover_fraction	snow cover fraction	“fraction”
spec_humidity_surface	diagnostic specific humidity at surface	“kg/kg”
ground_heat_total	soil heat flux	“W/m2”
runoff_baseflow	drainage runoff	“mm/s”
latent_heat_total	latent heat flux	“W/m2”
sensible_heat_flux	sensible heat flux	“W/m2”
evaporation_potential	potential evaporation	“mm/s”
runoff_surface	surface runoff	“mm/s”
latent_heat_ground	direct soil latent heat flux	“W/m2”
latent_heat_canopy	canopy water latent heat flux	“W/m2”
snow_sublimation	sublimation/deposit from snowpack	“mm/s”
soil_moisture_total	total soil column moisture content	“mm”
precip_adv_heat_total	precipitation advected heat - total	“W/m2”
cosine_zenith	cosine of zenith angle	“-”
snow_levels	active snow levels	“-”
temperature_leaf	leaf temperature	“K”
temperature_ground	ground temperature	“K”
canopy_ice	canopy ice	“mm”
canopy_liquid	canopy liquid	“mm”
vapor_pres_canopy_air	water vapor pressure in canopy air space	“Pa”
temperature_canopy_air	temperature in canopy air space	“K”
canopy_wet_fraction	fraction of canopy covered by water	“-”
snow_water_equiv_old	snow water equivalent - before integration	“mm”
snow_albedo_old	snow albedo - before integration	“-”
snowfall	snowfall	“mm/s”
lake_water	depth of water in lake	“mm”
depth_water_table	depth to water table	“m”
aquifer_water	aquifer water content	“mm”
saturated_water	aquifer + saturated soil water content	“mm”
leaf_carbon	carbon in leaves	“g/m2”
root_carbon	carbon in roots	“g/m2”
stem_carbon	carbon in stems	“g/m2”
wood_carbon	carbon in wood	“g/m2”
soil_carbon_stable	stable carbon in soil	“g/m2”
soil_carbon_fast	fast carbon in soil	“g/m2”
leaf_area_index	leaf area index	“m2/m2”
stem_area_index	stem area index	“m2/m2”
snow_age	BATS non-dimensional snow age	“-”
soil_moisture_wtd	soil water content between bottom of the soil and water table	“m3/m3”
deep_recharge	deep recharge for runoff_option 5	“m”
recharge	recharge for runoff_option 5	“m”
temperature_2m	grid diagnostic temperature at 2 meters	“K”
spec_humidity_2m	grid diagnostic specific humidity at 2 meters	“kg/kg”
eq_soil_water_vol	equilibrium soil water content	“m3/m3”
temperature_snow	snow level temperature	“K”
interface_depth	layer-bottom depth from snow surface	“m”
snow_level_ice	ice content of snow levels	“mm”
snow_level_liquid	liquid content of snow levels	“mm”

Restart files are located in the inputs/DATA_RESTART directory (downloaded above from the data bucket). Each forecast cycle also outputs restart files that can be used as input for the next cycle date(s). These restart files will appear in the /ptmp/<envir>/com/landda/v<X.Y.Z>/landda.${PDY}/RESTART directory. However, users can generate their own RESTART files by running a coldstart GDAS or WM experiment and using the RESTART files produced.

3.2.3. Output Files 

Output files for each cycle appear in the ${BASEDIR}/ptmp/<envir>/com/landda/v<X.Y.Z>/landda.${PDY} directory. Users can also reach this directory via a shortcut in the experiment directory: ${BASEDIR}/exp_case/lnd_era5_warmstart_00/com_dir/landda.${PDY}. This directory contains subdirectories with experiment output for each cycle:

hofx
plot
RESTART

The hofx directory contains information from the data assimilation that is used by the plotting tasks to create plots, which are stored in the plot directory. The RESTART directory contains RESTART files for the next cycle.

3.2.4. Viewing NetCDF Files 

Many Land DA System input and output files are in NetCDF format. Users can view file information, variables, and notes for NetCDF files using the ncdump module. The -h option provides summary (“header”) information. On Level 1 platforms, users can load the Land DA environment from land-DA_workflow:

cd ${BASEDIR}/land-DA_workflow
module use modulefiles
module load wflow_<platform>

where <platform> is ursa, orion, hercules, or gaeac6.

Then, users can load netcdf and run ncdump -h path/to/filename.nc, where path/to/filename.nc is replaced with the path to the file. For example, on Hercules, users might run:

cd ${BASEDIR}/land-DA_workflow
module use modulefiles
module load wflow_hercules
ncdump -h /work/noaa/epic/UFS_Land-DA_v3.0/inputs/NOAHMP_IC/ufs-land_C96_init_fields.tile1.nc

On other systems, users need to load NetCDF modules before running the ncdump command above. This may also require users to load a compiler and MPI module. For example:

module load netcdf-c/4.9.2
ncdump -h /path/to/inputs/NOAHMP_IC/ufs-land_C96_init_fields.tile1.nc

Users may need to modify the module load command to reflect modules that are available on their system. On many systems, the module avail command can show users which modules are currently available to load, while the module spider command shows all modules on the system and identifies their dependencies so that users can load them in the proper order.