CEDA Archive

This article describes accessing the CEDA Archive  from JASMIN:

Overview  

The CEDA Archive provides direct access to thousands of atmospheric, climate change and earth observation datasets. The Archive is directly accessible as a file system from the shared science machines on JASMIN.

It is a separate service run by the CEDA team - it is not a JASMIN service. Therefore, many of the links in this document will take you to the CEDA Archive help documentation site  (as the information relates to CEDA Archive services). This is separate from the JASMIN help documentation site (which is specifically about JASMIN services).

Register for a CEDA Account  

First, you need a CEDA Archive account. If you do not have a CEDA account, please follow the steps in this CEDA help document  to register as a new CEDA user. It also explains how you can reset your password if you have forgotten it. When you have made a CEDA account, you will then need to use the CEDA portal to link it to your JASMIN account  .

The JASMIN Account Portal deals with the management of access to JASMIN resources (e.g. compute and storage), whereas MyCEDA  (the CEDA Accounts Portal) deals with access to CEDA resources (e.g. access to datasets in the archives). You will need both accounts linked in order to access CEDA Archive data from JASMIN - you can check whether your accounts are linked from within the CEDA Accounts Portal  .

Accessing the CEDA Archive on JASMIN servers  

Once you have linked your CEDA and JASMIN accounts, you will have access to large parts of the archive straightaway.

The contents of the CEDA Archive are available on the file system under /badc and /neodc. Note: do not access data via any symlinks that point to /datacentre/archvol* - these are not permanent links and may change when data are migrated to new storage. Please use the archive path names under /badc and /neodc. Search the CEDA data catalogue  for further details about data held in the archive.

Note: /badc is for atmospheric & climate model data, /neodc is for earth observation data - they are named after CEDA’s previous archive names (British Atmospheric Data Centre, and the NERC Earth Observation Data Centre).

Most data on the Archive is open access - however, some datasets are restricted. You can work this out by looking at the UNIX access groups the data are within (see below). If your required datasets are restricted, access to these can be obtained by applying for specific access via the data centre (see this article   for more details). If direct access is not possible the data can be obtained via standard FTP and web-based  access methods to the CEDA Archive and transferred to a suitable group workspace on JASMIN. As the data centres use the same JASMIN infrastructure the transfer rates are high.

The CEDA Data Catalogue  is a useful tool to find and apply for access to datasets.

Archive access groups  

The UNIX access groups used within the CEDA Archive are listed below with links to example datasets in the CEDA data catalogue for those wishing to use them:

• open Available to any logged in JASMIN user with a linked CEDA user account. See a full list of available datasets here  .
• cmip5_research restricted CMIP3  and CMIP5   datasets
• esacat1 Satellite data including MERIS  , MIPAS  and SCIAMACHY  .
• ecmwf Access to the ECMWF Operational Datasets  .
• eurosat Satellite data including IASI  , AVHRR-3  and GOME-2  .
• ukmo_wx Met Office observational dataset collections including LIDARNET  , MIDAS  , MetDB  and NIMROD 
• ukmo_clim Climatology datasets from the Met Office, including Central England Temperature  dataset collection, HadISST  .
• byacl These data have specific restrictions on them meaning that they can’t be accessed directly from JASMIN, but can be obtained via FTP and web access.

Data Licensing  

All use of data accessed directly from the CEDA Archive must be used in line with the relevant data licence in place for the relevant dataset for the purposes stated in the access application. Data licence information can be found on the relevant CEDA Data Catalogue page, a link to which can be found in the 00README_catalogue_and_licence.txt files found in the archive. For specific data licences granted for restricted datasets, users should log into their MyCEDA page to view their granted licence and the associated usage purpose under which access was granted. Any required alternative use of the data beyond the original purpose stated in the original licence application can only be made with a freshly granted new licence application.

Accessing data in the archive  

In the example below, the logged-in user is listing the contents of the CRU data sets within the BADC archive. These are “open” so all logged-in users can access them:

ls -l /badc/cru/data
total 320
-rw-r-----  1 badc open  396 Feb 18  2015 00README
drwxr-x---  8 badc open 4096 Mar 22 10:32 cru_cy
drwxr-x---  4 badc open 4096 Dec  6  2014 crutem
drwxr-x--- 12 badc open 4096 May  9 14:11 cru_ts
drwxr-x---  3 badc open 4096 Feb 18  2015 PDSI

The CEDA Archive Data Browser  is a good place to start as it gives a web-based view of the data with additional metadata but enables copying & pasting the directory path for use within the JASMIN environment: