# CORA dataset

CORA (standing for Coriolis Ocean database ReAnalysis) is a global oceanographic temperature and salinity dataset produced and maintained by the French institute IFREMER. Most of those data are real-time data coming from different types of platforms such as research vessels, profilers, underwater gliders, drifting buoys, moored buoys, sea mammals and ships of opportunity.

## Description

This in-situ dataset produced by the French institute Ifremer in the framework of the European project MyOcean and French project CORIOLIS is a picture of the content of the operational oceanographic database CORIOLIS. This database is the main tool of Coriolis project which is a global data assembly center of in situ data: such as US-GODAE centre of Monterey in California. The latest version of CORA product is v5.0, it covers the years 1950 up to 2015 and has been released in April 2017. Observations are profiles distributed on measured levels (pressure or depth) and organized by dates of measurement and type of platform. Main users of CORA dataset are ocean modelers who needs to constraint and initialize their model. CORA is free of access and can be download via CORIOLIS website in netCDF file format. The main different of CORA dataset with other available datasets is that CORA provides data at depth levels where measurements were made rather than at standard levels such as in World Ocean Atlas or ENACT3. In addition data in CORA are retrieved from Coriolis database where each profile is visually checked by specialist operators if suspicious.

## Validation procedure
### Validation in database

* duplicate observation check
* automatic checks (spikes, climatology, monotonic depth, valid date/position,...)
* objective analysis (ISAS software with 21 days, 300 km covariance ray): suspicious observations are visualized by an operator

### Validation post extraction

* second duplicate observation check (detection and choice parameters tuned)
* refined climatological test
* XBT depth correction
* second objective analysis with tuned parameters: anomalies are visualized
* ARGO special diagnostics

## Data sources

The CORA dataset is designed for operational oceanography, so most global real time monitoring networks are plugged into this database. The data sources are the following:
* ARGO (autonomous drifting profilers)
* The global network of moored buoys comprising the TAO/TRITON, PIRATA and RAMA arrays
* EGO (underwater gliders)
* GTSPP (channel of real-time data distribution maintained by the US institute NOAA)
* GOSUD thermosalinograph data coming from opportunity ships
* GTS (BATHY, TESSAC, drifting buoys messages) channel of low resolution data distribution
* Sea mammals equipped with sensors (seals and sea elephants)
* other datasets integrated in delayed-time (CTD, XBT, oceanographic cruises,...)

## Versions

official versions of CORA product :
| | Date of release | Time span | Comments |
| CORA1.0 | 2007 | 2002-2006 | Beta version of the dataset, full years extracted |
| CORA2.2 | 2009 | 1990-2008 | Add of validation procedures (climatological checks) and gridding of the data |
| CORA3.1 | 2010 | 1990-2009 | Full years updated + 2009 added |
| CORA3.2 | 2011 | 1990-2010 | Add of validation procedures (duplicate check, XBT depth correction) integration of sea mammals data, automatisation of the update procedure |
| CORA3.3 | 2012 | 1990-2011 | Article submitted to Ocean Science review, add of year 2011, completion of anomalies feedback from objective analysis towards CORA dataset and Coriolis database. |
| CORA3.4 | 2013 | 1990-2011 | New ICES CTD data added |
| CORA4.0 | 2014 | 1990-2012 | Update of profiles and addition of Time series from drifters, ferrybox, profilers. |
| CORA4.1 | 2015 | 1950-1989 (Extraction from EN4), 1990-2013 | Addition of TSG data, delayed mode sea mammals and surface drifters + Integration of XBT and CTD from EN4 |
| CORA4.2 | 2016 | 1950-1989 (Extraction from EN4), 1990-2014 | Inclusion of 2,4 million profiles from the SHOM (Service Hydrographique de la Marine), mostly of XBTs CTDs and MBTs from 1950 to 2009 |
| CORA5.0 | 2017 | 1950-2015 | |