Web-MARS is a set of web applications giving you access to MARS through your web browser e.g. by browsing the MARS Catalogue, retrieving data etc. The MARS Catalogue is dynamically built from the content of MARS meta data databases as you browse them. The MARS Catalogue represents the exact state of the MARS content. Every single one of the billions of meteorological fields can be reached and retrieved from there.

In Web-MARS you can click through the archive, starting at various entry points. This is in contrast to using a MARS request where you need to know exactly how to describe a particular field before retrieval.

When browsing through the MARS Catalogue you will end up on a page where to make your final choice of data and chose one of the following options: 

  • Check for availability
  • View the MARS request
  • Estimate download size
  • Retrieve the selection in GRIB or NetCDF (experimental)

Web-MARS should mainly be used to locate particular data in the archive rather than to retrieve huge data volumes from MARS: Start with the most suitable archive 'view' to search for the data you are interested in, once you are on the last page (and probably after you have checked the availability of the data) choose the second option above, 'View the MARS request', and use the piece of MARS request, e.g. with further modifications to the date keyword, with the mars command in a batch job. The usage of the mars command and the MARS language are explained in some detail in this user guide.

The MARS system responds to tens of thousands of requests daily. The duration of a retrieval depends on the number of concurrent requests the system is processing and the amount of data retrieved, as well as the number of tape mounts involved. You can monitor the progress of your requests from the Server Activity.

Another useful tool is the Parameter Database which for each parameter shows how it is coded in GRIB format and lists the parameter ID, long and short name and the unit. For many parameters it will also provide links to the IFS documentation.