#Copmare observations meteo data and model output

This project provides tools for operating and comparing observed meteo conditions and gridded fields of meteo quantities produced by an atmospheric model.

Tools are based on NCAR Command language (ncl). The source data are converted into the netCDF format to be operated.

Data sources

List of WMO stations {#wmo-list}

The official list of meteo stations provided by WMO is here. It is hard to be combined into a single file, so the tool uses the list downloaded here here. It is not ultimately full and may become outdated. If so you may edit it manually.

Meteo observations

Currently the only supported format of meteo observations is isd-lite. You can download data the from NCAR database. The files have format XXXXX0-99999-YYYY where XXXXX is WMO id of a stations and YYYY is a year of reported observations.

Atmospheric models

Currently the only model which output is supported is Arctic System Reanalysis NCAR of both 15km and 30km resolutions. You can download data there. Register If you have no NCAR account. For the script to operate it needs at least full one-year set of model data.

Dependencies

You need UNIX and ncl-ncarg package (v6.4.0) installed .

How to use

This section gives step-by-step instructions how to compare observations and model results using tools provided here. There are two ways to operate the scripts: using command line arguments or editing the configuring script workspace/config.ncl

1. Update the file data/wmo_ids.txt with list of WMO stations if needed. See wmo list section

2. Enter working directory

    cd workspace

3. Convert wmo stations list data/wmo_ids.txt from text format to a netCDF format file netcdf/workspace/wmo_ids.nc.

    ncl wmoid_to_netcdf.ncl

   To change default input and output files edit values of wmo_ids_list_txt, wmo_ids_list_nc attributes in configurating script workspace/config.ncl or pass command line arguments when running the script:

    ncl wmoid_to_netcdf.ncl 'wmo_ids_list_txt="../data/wmo_ids.txt"' 'wmo_ids_list_nc="./netcdf/wmo_ids.nc"'

4. Download isd-lite into data/isd. Convert them to a netCDF format. List wmo identifiers in the attribute wmo_ids of configuring script or pass as cmd option. For setting periods of time list years with 'years'. If you need only one station wmo_id cmd argument is recognized, for one year only you may pass year argument.

    ncl isd_to_obs.ncl 'wmo_ids=(/ "23724", "01025", "71916"/)' year=2004

   This converts files ../data/isd/XXXXX0-99999-2004 to ./workspace/netcdf/obs_XXXXX-2004.nc adding station metadata from ./netcdf/wmo_ids.nc. You may change defaults using wmo_ids_list_nc, isd_dir, and obs_nc_prefix options.

5. Interpolate ASR gridded data to station observations. Pass isd_nc_dir to set directory where isd files are searched, to set stations pass wmo_id or wmo_ids, to set years pass year or years, to set directory where asr file are searched pass asr_dir, pass asr_prefix: source asr files are {asr_dir}/asr_prefix-YYYYMMDD.nc, pass output_prefix to produce output files {output_prefix}_XXXXX-YYYY

     ncl asr_to_obs.ncl 'isd_nc_dir="./netcdf"' 'asr_dir="~/workspace/data/asr30"' 'asr_prefix="asr30km.anl.2D."' 'wmo_ids=(/"23724", "01025", "71916"/)' year=2004 'output_prefix="netcdf/asr30"'

6. To plot observed values and corresponding model values run at one graph run

    ncl compare.ncl

For developers

• To print sea level pressure provided by reanalisys run

    ncl plot.ncl

• station.ncl seems to be not working

• check_re.ncl is not ready yet