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Users do not have root access. In order to allow them to install python packages they have to setup a virtual environment.

Those with root access, or that have already configured a working python environment can go tho the next session

To fully cover the topic of installing virtual environments, users can look at this tutorial Using virtual Python environment.

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source ~/.bashrc # (or source use_environments)


mkvirtualenv cdsapi # or add -p [path to python executable you wish to use it can be different from the one specified in the set up script]


workon cdsapi # to activate the environment / deactivate    # to deactivate the environment

After entering the virtual environment using the command workon, we can use pip to install any package available via PyPI.

Installing the API using pip

Just execute:

pip install cdsapi

Or in case of root install sudo pip install cdsapi

For non linux/mac users

The point is to download and install your favorite python version then install the command pip, following common instructions, set up the command line environment to point to python and pip and then run pip install cdsapi.

Using the API 

Installing credentials

Users have to locate theyr credentials on the climate data store.

In order to have credentials, users must register in the climate data store.

Registered users can access https://cds.climate.copernicus.eu/api-how-to and locate the fieeld named "Install the CDS API key" .

The two lines specifying url and key must be copied ina specific file: $HOME/.cdsapirc

Non linux like users at the moment can use the credentials within the applications without using the file .cdsapirc (this means that they will produce code exposing the credentials which is a bad habit).

Disabling the ECMWF's proxy settings

For users using non ECMWF's computers (windows and othere notebooks) this step is not necessary.

In order to use the web api we need that in the environment

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running it the proxy settings are deactivated (this because the CDS is within the premesis)

To achieve this goal, in the console with the cdsapi environment type:

export http_proxy=
export https_proxy=

Just type enter after = !

Retrieving data

The 2 examples presented in https://cds.climate.copernicus.eu/api-how-to  are a good and simple examples working under unix like systems

#!/usr/bin/env python
import cdsapi
c = cdsapi.Client()
c.retrieve("reanalysis-era5-pressure-levels",
               {
                "variable": "temperature",
                "pressure_level": "1000",
                "product_type": "reanalysis",
                "date": "2008-01-01",
                "time": "12:00",
                "format": "grib"
                },
               "download.grib")

#!/usr/bin/env python
import cdsapi
c = cdsapi.Client()

c.retrieve("insitu-glaciers-elevation-mass",
				{
				 "variable": "elevation_change",
				 "format": "tgz"
				 },
				"download.tar.gz")

In case the user is using python under windows, the script need to be changed.

The change involve onlu the code line c = cdsapi.Client()

It must be changed in:

c = cdsapi.Client(api_key=[your key as specified in the api-how-to], end_point=''https://cds.climate.copernicus.eu/api/v2")

More hands on example:

#!/usr/bin/env python
import cdsapi
from datetime import datetime, timedelta

p_levels = [str(z)  for z in ([1] + list(range(50, 1050, 50)))]
c = cdsapi.Client()


def days_of_month(y, m):
    d0 = datetime(y, m, 1)
    d1 = datetime(y, m + 1, 1)
    out = list()
    while d0 < d1:
        out.append(d0.strftime('%Y-%m-%d'))
        d0 += timedelta(days=1)
    return out

for y in range(2008, 2018):
    for m in range(1,13):
        for d in days_of_month(y, m):
            c.retrieve("reanalysis-era5-pressure-levels",
                       {
                           "variable": "temperature",
                           "pressure_level": p_levels,
                           "product_type": "reanalysis",
                           "date": d,
                           "time":[
                               '00:00','01:00','02:00',
                               '03:00','04:00','05:00',
                               '06:00','07:00','08:00',
                               '09:00','10:00','11:00',
                               '12:00','13:00','14:00',
                               '15:00','16:00','17:00',
                               '18:00','19:00','20:00',
                               '21:00','22:00','23:00'
                           ],
                           "format": "netcdf"
                       },
                       "ea_t_{day}.nc".format(day=d)
                       )

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