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FAQSolution

General

Why are my requests in a 'running' or 'pending' state for a long time?

The Climate Data Store is used daily by thousands of users requesting and processing data. It is possible that sometimes the system goes under stress.

CEMS-flood datasets are archived in MARS (Meteorological Archival and Retrieval System). Every Wednesday there is a MARS system session, that can affect request queuing time.

More information in CDS - Best Practices.

EFAS

How do I spatially subset the dataset?

Currently, there is no service to subset/ crop EFAS data. CEMS-Flood is developing a tool to do this which will be made available in future (see Extract subset of CEMS-Flood Data for further details).

GloFAS

How do I spatially subset the dataset?

It is possible to subset GloFAS datasets using the 'area' keyword in the CDS API request,

example request 
import cdsapi

c = cdsapi.Client()

c.retrieve(
    'cems-glofas-reforecast',
    {
        'system_version': 'version_2_2',
        'variable': 'river_discharge_in_the_last_24_hours',
        'format': 'grib',
        'hydrological_model': 'htessel_lisflood',
        'product_type': 'control_reforecast',
        'hyear': '2016',
        'hmonth': 'january',
        'hday': '10',
        'leadtime_hour': '24',
        'area': [
            10.95, -30.95, -15.75, 30.05, # North West South East
        ],
    },
    'download.grib')


or directly by using the "Geographical area" widget in the CDS download form.



Why are latitude and longitude coordinates are multiples of 0.05?

In the GRIB format, the data field is represented by a grid of points. 

GloFAS datasets have a spatial resolution of 0.1x0.1 degrees.

The points coordinates, multiple of 0.05 and spaced by 0.1 degrees, represent the centre of a cell of 0.1x0.1 degree.

Why does the GRIB format have longitude ranges between 180 and 540?

GRIB format does not allow negative longitude values, therefore the range is computed adding 360 to the longitude range (180 = -180 + 360, 540 = 180 + 360).

When reading GRIB with the Python Xarray/CFGRIB converter, the tool automatically converts the range back to -180 to 180. 

Potential How-to pages / FAQs:

  • How to extract a time-series for a single point from one of the EFAS/GloFAS datasets (Re: Extracting single point)
  • Timeout errors / Delays when retrieving data from CDS
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