This package provides access to the Climate Data Store (a.k.a. CDS) service.

The CDS website provides a Show API request button at the bottom of the download tab of each dataset. This button generates the code to download the dataset with the Python cdsapi module. I've designed this class so that one could copy/paste the generated Python code with minimum modification in C#.

The code in based on the explanations provided in the ECMWF forum: https://forum.ecmwf.int/t/ecmwf-apis-faq-api-data-documentation/6880/1. I've use it in personal ML/DL projects for water resources assessment propertly.

The package will attempt to use CDS credentials using three different methods with the following priority:

1. direct credentials provided through the scoped values `CDSAPI.KEY` and `CDSAPI.URL`
2. environmental variables `CDSAPI_URL` and `CDSAPI_KEY`
3. default credential file in home directory `~/.cdsapirc`

A valid credential file is a text file with two lines:

url: https://yourendpoint
key: your-personal-api-token

Instructions on how to create the file for your user account can be found here.

For the following example to work, make sure your ~/.cdsapirc file exists or the env vars CDSAPI_URL and CDSAPI_KEY are set.

Suppose that the Show API request button generated the following Python code:

#!/usr/bin/env python
import cdsapi

dataset = "reanalysis-era5-single-levels"
request = {
    "product_type": ["reanalysis"],
    "variable": [
        "10m_u_component_of_wind",
        "10m_v_component_of_wind"
    ],
    "year": ["2024"],
    "month": ["12"],
    "day": ["06"],
    "time": ["16:00"],
    "data_format": "netcdf",
    "download_format": "unarchived",
    "area": [58, 6, 55, 9]
}

client = cdsapi.Client()
client.retrieve(dataset, request).download()

You can obtain the same results in C#:

var dataset = "reanalysis-era5-pressure-levels-monthly-means";
var filename = "era5.grib";
var request = new Dictionary<string,object>() {
            {"data_format", "grib"},
            {"product_type", "monthly_averaged_reanalysis"},
            {"variable", "divergence"},
            {"pressure_level", "1"},
            {"year","2020"},
            {"month","06"},
            {"area", new double [] {90,-180,-90,180}},
            {"time","00:00"}
        };

var response = await CDSAPI.Retrieve(dataset, request, filename);

Besides the downloaded file, the retrieve function also returns a dictionary with metadata:

Dict{String,Any} with 6 entries:
  "result_provided_by" => "8a3eb001-c8e3-4a9c-8170-28191ebea14b"
  "location"           => "http://136.156.133.36/cache-compute-0010/cache/data0/dataset-insitu-glaciers-elevation-mass-8a3eb001a14b.tar.gz"
  "content_type"       => "application/gzip"
  "request_id"         => "04534ef1-874d-4c81-bb59-9b5effe63e9e"
  "content_length"     => 193660
  "state"              => "completed"