ALCF

Automatic Lidar and Ceilometer
Framework

Documentation

Model guide

The following GCM, NWP models and reanalyses are supported:

Note: The ERA-Interim reanalysis is not supported due to the required fields (mass fraction of cloud liquid water and ice in air) not available in the dataset.

Below is a description of the model output supported by the ALCF. You might have to modify the code for reading the model output depending on the exact format of the model output, such as variable names and how they are split among the output files.

AMPS

Source: alcf/models/amps.py

The ALCF is compatible with the NetCDF AMPS output. You can find the AMPS archive on the Earth System Grid (ESG) website. The following files conver 24 hours of model output:

wrfout_dxx_YYYYmmdd00_f003.nc
wrfout_dxx_YYYYmmdd00_f006.nc
wrfout_dxx_YYYYmmdd00_f009.nc
wrfout_dxx_YYYYmmdd00_f012.nc
wrfout_dxx_YYYYmmdd12_f003.nc
wrfout_dxx_YYYYmmdd12_f006.nc
wrfout_dxx_YYYYmmdd12_f009.nc
wrfout_dxx_YYYYmmdd12_f012.nc

where xx is the AMPS grid, YYYYmmdd is the year (YYYY), month (mm) and day (dd). The *_f000.nc files are not suitable for use with the ALCF as they do not contain all required variables.

ERA5

Source: alcf/models/era5.py

ERA5 reanalysis data can be downloaded from Copernicus. Download the following datasets:

ERA5 hourly data on pressure levels from 1979 to present

ERA5 hourly data on single levels from 1979 to present

Save the pressure-level files in a directory named plev and the surface-level files in a directory named surf. Pass the path to the parent directory to alcf model or alcf auto model.

JRA-55

Source: alcf/models/jra55.py

The JRA-55 reanalysis data can be downloaded from the JRA-55 project website. The following fields are required by the ALCF:

Download files for the period of interest all into the same directory. The JRA-55 GRIB files have to be converted to NetCDF before they can be used with the ALCF. Use grib_to_netcdf to convert the data. All data files should reside in the same directory.

MERRA-2

Source: alcf/models/merra2.py

MERRA-2 reanalysis files can be found via the NASA EarthData portal. Description of the MERRA-2 products can be found in the MERRA-2: File Specification document. The model-level products are recommended due to their higher resolution. Only the “Assimilated Meteorological Fields” contain the required variables. The recommended product is the “inst3_3d_asm_Nv (M2I3NVASM): Assimilated Meteorological Fields”, i.e. the 3-hourly instantaneous 3D assimilated fields on model levels. You can find the product files by searching for “M2I3NVASM” on NASA EarthData, or directly on the NASA EOSDIS FTP server.

NZCSM

Source: alcf/models/nzcsm.py

New Zealand Convective Scale Model (NZCSM) is a NWP model based on the UK Met Office Unified Model. The following model output variables are needed to run the lidar simulator:

NZESM (experimental)

Source: alcf/models/nzesm.py

New Zealand Earth System Model output is a model based on HadGEM3. The model output variables needed are:

UM

Source: alcf/models/um.py

The NetCDF output (configuration option l_netcdf) of the UK Met Office Unified Model (UM) is supported. The following variables are required:

ALCF <= 1.0.0-beta.2:

ALCF > 1.0.0-beta.2:

The variables should be provided on all theta levels and as high temporal sampling as possible (instantaneous). All variables should be dumped together to the same NetCDF file, split by time into arbitrary number of files.

In addition, a file containing model orography is required. Convert the model grid qrparam.orog file distributed with the UM to NetCDF with iris:

python -c "import iris;c=iris.load('qrparm.orog');iris.save(c,'qrparm.orog.nc')"

and put qrparm.orog.nc in the same directory as the model output files.