Skip to content

Globsim

stgruber edited this page Aug 6, 2017 · 20 revisions

About

Globsim helps you to download reanalysis data from ERA-Interim, MERRA2, and JRA-55 for a target area and to interpolate it to point time series for individual locations (here called 'stations'). This is intended to replace or supplement meteorological observations in remote areas. This page provides high-level information that is required as an entry point to using Globsim. All python code is documented with comment and (doxypyppy?). The sub-directory examples/ contains examples of relevant control files.

Directories and files

Globsim weeks with three differing directories. The source directory is what is contained in this GitHub repository (default: ~/src/globsim). The credentials directory is where your login credential files for the differing reanalyses are found (default: ~/.). The project directory is the location to which data is downloaded and where processed data is found. The project directory is subdivided by re-analysis type and by the type of derived product.

Credentials directory

Contains credentials files with login information, see directory examples/.

 .ecmwfapirc  (ERA-Interim credentials)
 .merrarc     (MERRA2 credentials)
 .jra55rc     (JRA-55 credentials)

Project directory

 project_a/              (project directory)
 project_a/jra-55/       (JRA-55 data)
 project_a/eraint/       (ERA-Interim data)
 project_a/merra2/       (MERRA 2 data)
 project_a/par/          (parameter files for data download and interpolation)

Download parameter file

 # This is an example of a Globsim download parameter file
 # Use extension like this: 'project_a.globsim_download'

 # logistics
 project_directory = /home/sgruber/src/globsim/examples/
 credentials_directory = ~/.

 # chunk size for splitting files and download [days]
 chunk_size = 5

 # area bounding box [decimal degrees]
 bbN = 65.0
 bbS = 64.0 
 bbW = -111.0
 bbE = -110.0

 # ground elevation range within area [m]
 ele_min = 0
 ele_max = 2000

 # time slice [YYYY/MM/DD]
 beg = 1980/01/01
 end = 1980/01/03

 # variables to download [CF Standard Name Table]
 variables = air_temperature, relative_humidity, precipitation_amount, downwelling_longwave_flux_in_air, downwelling_shortwave_flux_in_air, downwelling_shortwave_flux_in_air_assuming_clear_sky, wind_from_direction, wind_speed

Interpolation parameter file

This is an example of a Globsim interpolation parameter file. It defines the project directory to be used, the desired time slice and the desired variables for interpolation. Use extension like this: 'my_stations.globsim_interpolate'

 # logistics
 project_directory = /home/sgruber/src/globsim/examples/

 # time slice [YYYY/MM/DD]
 beg = 1980/01/01
 end = 1980/01/02

 # variables to download [CF Standard Name Table]
 variables = air_temperature, relative_humidity, precipitation_amount, downwelling_longwave_flux_in_air, downwelling_shortwave_flux_in_air, downwelling_shortwave_flux_in_air_assuming_clear_sky, wind_from_direction, wind_speed

Station list for interpolation

This is an example of a Globsim station list file. The resulting netCDF file will use the station numbers as identifiers. Use extension like this: 'my_stations.csv'

 station_number, station_name, longitude_dd, latitude_dd, elevation_m 
 1, yellowknife_airport, -114.44234, 62.46720, 207
 2, ekati_airport, -110.60804, 64.70591, 461