e2o_getvar - retrieve variables

e2o_getval gets variables from the server for a specific region (specified in the ini file) and optionally resamples those to a specified Digital Elevation Model (DEM). e2o_getvar outputs daily values in the original units. The script does physical downscaling only for Temperature and Precipitation. The other variables are interpolated only. In order to downscale the precipitation data you must first download the data from: https://github.com/earth2observe/downscaling-tools/releases/tag/2016-data-prec. We use the WorldClim data, see Hijmans et. al. 2005. If you have other high resolution climatology data you can use that instead of the worldclim data.

Note

Use the e2o_calculateEvaporation script for more elaborate downscaling options for evaporation and the variables needed to calculate it.

Usage:

e2o_getvar.py -I the_ini_file

ini file configuration

The .ini file below shows the available options

# This example downloads and resamples the MSWEP precipitation data
# MSWEP is the precipitation forcing of the WRR2
# The file is setup to retrieve a full year of data

# Example 1: resample only



[url]
# WRR1 (EI with corrections and MSWEP)
# Leave these as they are unless you have specific needs
serverroot = http://wci.earth2observe.eu/thredds/dodsC/
wrrsetroot = jrc/MSWEP/daily_e2o_netcdf_convention/


[selection]
# set the start and end year, month and day
startyear = 1979
endyear= 1979
startmonth = 1
endmonth = 12
startday = 1
endday = 31

# Resample to a local dem (must be specified later on)
resampling=True
# Set the variable to use here, see the table in the documentation for names
variable=Rainfall
filename=Rainf_daily_MSWEP_025_
standard_name=rainfal_flux


#Table: Variables and names to be used in the ini file

#==================================== ====================== ==================== =========================================
#Variable                             Filenames WRR2         Filenames WRR1       standard_name
#==================================== ====================== ==================== =========================================
#Temperature                          Tair_daily_EI_025_     Tair_daily_E2OBS_    air_temperature
#DownwellingLongWaveRadiation         LWdown_daily_EI_025_   LWdown_daily_E2OBS_  surface_downwelling_longwave_flux_in_air
#SurfaceAtmosphericPressure           PSurf_daily_EI_025_    PSurf_daily_E2OBS_   surface_air_pressure
#NearSurfaceSpecificHumidity          Qair_daily_EI_025_     Qair_daily_E2OBS_    specific_humidity
#Rainfall                             Rainf_daily_MSWEP_025_ Rainf_daily_E2OBS_   rainfall_flux
#SurfaceIncidentShortwaveRadiation    SWdown_daily_EI_025_   SWdown_daily_E2OBS_  surface_downwelling_shortwave_flux_in_air
#SnowfallRate                         Snowf_daily_MSWEP_025_ Snowf_daily_E2OBS_   snowfall_flux
#NearSurfaceWindSpeed                 Wind_daily_EI_025_     Wind_daily_E2OBS_    wind_speed
#LapseRate                            lapseM_EI_025_                 -            air_temperature_lapse_rate
#TotalPrecipitation                   -                      -                    precipitation_flux
#==================================== ====================== ==================== =========================================


# Optional conversions
[conversion]
# to celcius
Temperature= Temperature - 273.15
# To mm
Rainfall= Rainfall * 86400

[downscaling]
# The local dem
highResDEM=wflow_dem.map
# If set to False, only interpolate
downscaling=False

# interpolation type: linear, nearest
interpolmethod=nearest


[output]
# Gdal output format string
# See: http://www.gdal.org/formats_list.html
# examples: AAIGrid, PCRaster, GTiff
format=GTiff
directory=output/
prefix=P

Table: Variables and names to be used in the ini file

Variable Filenames WRR2 Filenames WRR1 standard_name
Temperature Tair_daily_EI_025_ Tair_daily_E2OBS_ air_temperature
DownwellingLongWaveRadiation LWdown_daily_EI_025_ LWdown_daily_E2OBS_ surface_downwelling_longwave_flux_in_air
SurfaceAtmosphericPressure PSurf_daily_EI_025_ PSurf_daily_E2OBS_ surface_air_pressure
NearSurfaceSpecificHumidity Qair_daily_EI_025_ Qair_daily_E2OBS_ specific_humidity
Rainfall Rainf_daily_MSWEP_025_ Rainf_daily_E2OBS_ rainfall_flux
SurfaceIncidentShortwaveRadiation SWdown_daily_EI_025_ SWdown_daily_E2OBS_ surface_downwelling_shortwave_flux_in_air
SnowfallRate Snowf_daily_MSWEP_025_ Snowf_daily_E2OBS_ snowfall_flux
TotalPrecipitation
precipitation_flux
NearSurfaceWindSpeed Wind_daily_EI_025_ Wind_daily_E2OBS_ wind_speed
LapseRate lapseM_EI_025_
air_temperature_lapse_rate

TotalPrecipitation is a virtual name and will instruct the script to sum Rainfall and SnowfallRate.

Using the examples

examplerun1.ini

This example downloads and resamples MSWEP rainfall data (WRR2). No downscaling is applied. All output is stored in sequential geotiff files in output/Rainfall/P00EX100000.???, one for each timestep.

examplerun2.ini

This example downloads and resamples MSWEP rainfall data (WRR2). Downscaling is applied using nearest interpolation. Therefore you need to have downloaded and installed the Prec.zip file at: https://github.com/earth2observe/downscaling-tools/releases/tag/2016-data-prec All output is stored in sequential geotiff files in output/Rainfall/EX200000.???, one for each timestep.

examplerun3.ini

This example downloads and resamples MSWEP rainfall data (WRR2). Downscaling is applied using linear interpolation. Therefore you need to have downloaded and installed the Prec.zip file at: https://github.com/earth2observe/downscaling-tools/releases/tag/2016-data-prec All output is stored in sequential geotiff files in output/Rainfall/EX300000.???, one for each timestep.

examplerun4.ini

As example 3 but the output is saved in a netcdf file (output/Rainfall.nc)

examplerun5.ini

This example downloads and resamples MSWEP snowfall data (WRR2). Downscaling is applied using linear interpolation. Therefore you need to have downloaded and installed the Prec.zip file at: https://github.com/earth2observe/downscaling-tools/releases/tag/2016-data-prec All output is stored in sequential geotiff files in output/SnowfallRate/EX500000.???, one for each timestep.

examplerun6.ini

This example downloads and resamples WFDEI TotalPrecipitation (Rain and Snow) data (WRR1). No downscaling is applied but only resampling using linear interpolation. All output is stored in sequential geotiff files in output/TotalPrecipitation/EX6.???, one for each timestep.

examplerun7.ini

This example downloads and resamples WFDEI Air Temperature data (WRR1). Downscaling is applied using a fixed laps rate and
linear interpolation.

All output is stored in sequential geotiff files in output/Temperature/EX7000.???, one for each timestep.

examplerun8.ini

This example downloads and resamples MSWEP TotalPrecipitation (Rain and Snow) data (WRR2). All output is stored in sequential geotiff files in output/TotalPrecipitation/EX80000.???, one for each timestep.

examplerun9.ini

This example downloads and resamples MSWEP TotalPrecipitation (Rain and Snow) data (WRR2) for Fiji All output is stored in sequential geotiff files in output/TotalPrecipitation/EX90000.???, one for each timestep.

Implementation

Get a variable from the forcing data from the e2o server for a specific region and time range

usage:

e2o_getvar.py -I inifile [-l loglevel][-h]

-I inifile - ini file with settings which data to get -l loglevel (must be one of DEBUG, WARNING, ERROR)

See: http://e2o-downscaling-tools.readthedocs.io/en/latest/e2o_getvar.html

e2o_dstools.e2o_getvar.downscale(variable, data, datalow, wrrversion, serverroot, wrrsetroot, BB, currentdate, XH, YH, XL, YL, interpolmethod, ncoutfillval, hiresdem, resLowResDEM, interpolmode, logger, localdatadir='')
Parameters:
  • variable –
  • data –
  • wrrversion –
Returns:
e2o_dstools.e2o_getvar.save_as_mapsstack(lat, lon, data, times, directory, prefix='E2O', oformat='PCRaster')

Save a data matrix (multiple times) as a stack of (pcraster) maps.

Parameters:
  • lat –
  • lon –
  • data –
  • times –
  • directory –
  • prefix –
  • oformat –
Returns:
e2o_dstools.e2o_getvar.usage(*args)

Print usage information

  • *args: command line arguments given

References

Hijmans, R.J., S.E. Cameron, J.L. Parra, P.G. Jones and A. Jarvis, 2005. Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology 25: 1965-1978.