ECMWF open data can be retrieved from the Amazon S3 buckets using the earthkit or ecmwf-opendata Python libraries.
The earthkit and ecmwf-opendata package¶
Below, two examples for downloading data from the Amazon’s AWS location.
# !pip3 install earthkit ecmwf-opendatafrom ecmwf.opendata import Client
client = Client(source="aws")
request = {
"time": 0,
"type": "fc",
"step": 24,
"param": "2t",
}
client.retrieve(request, "aws_2t_data.grib2")
da_2t = ekd.from_source("file", "aws_2t_data.grib2")
da_2t.ls()import earthkit.data as ekd
data = ekd.from_source("s3", {
"endpoint": "s3.amazonaws.com",
"region": "eu-central-1",
"bucket": "ecmwf-forecasts",
"objects": "20230118/00z/0p4-beta/oper/20230118000000-0h-oper-fc.grib2"
}, anon=True)
ds = data.to_xarray()
dsRetrieve data for only one parameter¶
To download the single 2t parameter, we read the _offset and _length values from the corresponding index file.
index_file = ekd.from_source("s3",
{"endpoint": "s3.amazonaws.com",
"region": "eu-central-1",
"bucket": "ecmwf-forecasts",
"objects": "20250430/12z/aifs-single/0p25/oper/20250430120000-12h-oper-fc.index",
}, anon=True)
index_file = index_file.to_pandas()
value = index_file.iloc[[42]].to_string(index=False, header=False)
valuereq = {"endpoint": "s3.amazonaws.com",
"region": "eu-central-1",
"bucket": "ecmwf-forecasts",
"objects": { "object": "20250430/12z/aifs-single/0p25/oper/20250430120000-12h-oper-fc.grib2", "parts": (34015908, 560208)},
}
data = ekd.from_source("s3", req, anon=True)
data.ls()