Always refer to the MARS user documentation for up to date changes to the MARS Service.
Retrieving subareas of GloFAS data
The GloFAS grid can not be interpolated as that would return incorrect river discharge values.
Therefore, in MARS retrievals for subareas of GloFAS data the specified bounding box should match with the GloFAS grid, which includes points with coordinate values ending as .x25 or .x75 for v4.0, and as .x5 for earlier versions. For example, for v4.0 the area of [-8.425, 16.275, -20.625, 39.175] is appropriate, while for earlier versions it would be [-8.45, 16.25,-20.65, 39.15].
The MARS service grants users access to several hundred Petabytes of data on a mix of disk and tape storage.
It is important when accessing data inside MARS that we access the data in the most resonable way as doing this can help reduce wait times for our requests and for others.
As detailed in the MARS Web page, users can use the MARS Catalogue to build a request to submit to MARS.
Users can either request data via the catalogue or copy the output into a text file and submit it to the mars command for retrieval.
Regardless of how you will download the data, it is always best to use the Catalogue's
'Estimate Download Size' facility to check that the download you want to make is a reasonable request that is not going to sit in the queue for a long time
Users of MARS inside ECMWF will know this as the MARS LIST command.
The response of the 'Estimate Download Size' command can aid users in making informed decisions about their requested data.
Data is dispersed across tapes, usually depending on the dates.
A user requesting data over many tapes is likely to wait longer as the system has to load data from all of the tapes in order to return the data.
A user requesting data only on one tape can request several different requests as long as they are on different tapes.