The repository assumes responsibility for long-term preservation and manages this function in a planned and documented way
ESPRI manages and distributes data sets of different nature and from several reference sources, which require different levels of long-term archiving.
Climate model results do not all need to be archived in the long term. Climate models are improved over time superseding previous runs. It is commonly accepted by the designated community that climate models data are deprecated after seven years. Therefore, only a subset of climate model results used by the IPCC AR are archived in the long term by the DKRZ (Germany) for transparency and the reproducibility of analyses, statistics and figures.
Observations acquired from IPSL Observation Center or replicated from other partners must be archived in the long term to complete a long time series to be used in many impact studies.
In addition, ESPRI repository has a commitment as a DOI provider to maintain data and metadata over the long term, in accordance with DataCite requirements. The deletion of items from a data collection can be done at the request of the data provider only. This deletion is not automatic, but implemented by the ESPRI service. If a permanent identifier, such as DOI, has been registered on the dataset in ESPRI’s preservation custody, the metadata record is updated to inform of the deletion of the dataset and to refer to a new version for example.
The Data Management Plan details the archiving and preservation principles and processes applied by ESPRI repository, depending on the level of availability required for each data type.
A user guide has been added to the ESPRI website in order to introduce users to ESPRI data and services. They are encouraged to consult the DMP where they can easily read the preservation levels applied to ESPRI-managed data.
As a summary, the nature of ESPRI repository implies a disciplinary code of conduct in order to provide a relevant analysis reproducibility based in the following essential aspects that makes up the ESPRI preservation plan:
1. Long-lasting data formats and metadata that are adapted for long-term preservation and enable data reuse
The use of the formats guarantees the reconstruction of information systems over time independently of the used technologies (i.e. easier migration on different filesystems, standard conversion tools). For instance, the netCDF format was created in the 1970s by the UNIDATA consortium. This set of software libraries and necessary programming interfaces (Python, C, Fortran, etc.) are well-supported and regularly updated.
2. The resilience of the in-house migration/preservation procedures
ESPRI has been constantly monitoring its hardware performances to initiate updates when needed ; and passive preservation tasks needed to recover data from redundant storage. From the beginning of ESPRI, a number of migrations have been successfully performed without any loss of information that demonstrates the format/metadata robustness and the resilience of the migration/preservation procedures.
3. A long and solid collaboration with our partners
Through its multi-site implementation, ESPRI has a ten-year partnership with HPC partners. The close collaborations between both IT staffs led to build data management plans accommodating ESPRI preservation needs with their on-site security constraints in order to ensure a high level of data availability for users.
4. Solid and lasting partnerships established with identified custodians
ESPRI storage aims at identifying depositors who are partners in projects in which IPSL participates or coordinates. In such a case the depositor delegates data storage and access to ESPRI facilities. The depositor can also delegate the data transfer or make the copy himself by registering to the ESPRI center. The deposited data must conform to the Data Management Plan (DMP) of the projects co-authored by at least one ESPRI data manager. On the one hand, the DMP provides clear guidelines for deposit and easier transfer of custody of data to ESPRI (i.e. the conformance to our data and metadata requirements and the compatibility with our data preservation procedures). On the other hand, the deposited data can only be transformed by the depositor. ESPRI may not modify any data without the prior consent of the Prime Investigators of the projects. On request of the depositor, ESPRI maintains the copyright on the deposited data as well as restricted data access.