Hi all,
I’m trying to download ERA5 data in spherical harmonics, so as to compute accurate spatial derivatives of variables like pv, u, and v. The default resolution of T639 seems too computationally expensive for me for now, so I’m therefore wondering if I can request a more sparse truncation (T106, or T85) in the first place, or if there’s a tool for coarsening my downloaded T639 data… Thanks! Attaching code using api for reference:
import cdsapi
Create a CDS API client
c = cdsapi.Client()
Filename for the combined data
filename = ‘/nobackup1/x_yan/ERA5/spherical_isentropic/T85_19980101_20031231_isentropic.grib’
Retrieve data for selected time range with spectral truncation T85
c.retrieve(“reanalysis-era5-complete”, {
“class”: “ea”,
“date”: “1998-01-01/to/2003-12-31”,
“expver”: “1”,
“levelist”: “315/330/350”,
“levtype”: “pt”,
“param”: “60.128/131/132”,
“stream”: “oper”,
“time”: “00:00:00/06:00:00/12:00:00/18:00:00”,
“type”: “an”,
“grid”: “T85”, # Specifying spectral truncation T85
},
filename
)
which gives HTTPError: 400 Client Error: Bad Request for url: https://cds.climate.copernicus.eu/api/retrieve/v1/jobs/3c3202c4-b8c4-47b0-b1c9-608298d7ba3f/results
The job has failed.
MARS has returned an error, please check your selection.
Request submitted to the MARS server:
[{‘class’: [‘ea’], ‘date’: ‘1998-01-01/to/2003-12-31’, ‘expver’: [‘1’], ‘grid’: ‘T85’, ‘levelist’: ‘315/330/350’, ‘levtype’: ‘pt’, ‘param’: ‘60.128/131/132’, ‘stream’: ‘oper’, ‘time’: ‘00:00:00/06:00:00/12:00:00/18:00:00’, ‘type’: ‘an’, ‘database’: ‘fdbmarser’}]
Full error message:
mars - ERROR - 20250120.214725 - undefined value : T85 for parameter GRID
mars - ERROR - 20250120.214725 - Values are :
The job failed with: MarsRuntimeError