SO-WISE South Atlantic Ocean and Indian Ocean Observational Constraints

This dataset contains an initial set of curated and processed oceanographic observations collected as part of a joint effort between the EU SO-CHIC project and a UKRI Future Leaders Fellowship. It is partly intended to be used as a set of observational constraints for a Weddell Gyre region state estimate, although it can be used for more general analysis purposes as well. It has been used as part of an unsupervised clustering analysis [see Jones (2022) for software and Jones and Zhou (2022) for labelled dataset, see references]. 

Overall spatial and temporal coverage

• Latitude: 85°S-30°S
• Longitude: 65°W-80°E
• Time: 1974-2020

Contents

• CPOM_SSH: sea-ice corrected sea surface height 
• CTD: temperature and salinity profiles from ship-based CTD casts 
• FLOATS: temperature and salinity profiles from Argo floats 
• SEALS: temperature and salinity profiles from seal-mounted profilers
• Stress_and_EKE: sea-ice corrected surface stress and EKE 
• XBT: temperature and salinity profiles from expendable bathythermographs (XBTs)

Profile quality control

We only consider profiles with good position and time flags, as well as good temperature, salinity, and pressure measurements with good flags. Duplicated profiles are identified when multiple profiles are found within 24 hours over the same 2 km x 2 km grid cell, and only one profile within the spatio-temporal window is used. We then used the MITprof toolbox (Forget, G., 2017) to pre-process the selected profiles, re-gridding them onto 72 standard pressure levels; the vertical interval varies from 20 dbar at the surface to 100 dbar in the deep ocean. 

SSH processing

SSH data is sea-ice corrected version provided by the Centre for Polar Observation and Modelling (CPOM) in the UK. It is composed by two satellite missions, Envisat (2004/05-2012/03) and Cryosat-2 (2010/07-2020/04). The data is available in montly along-track format. A gaussian 300km filter, ±3 std outliner removal and 0.5x0.25 deg interpolation is applied to grid the data. Intersatellite offset is removed using the overlapped period between two missions using the mean difference map. SSH is referenced to EIGEN6C4 geoid to obtain the dynamic ocean topography feild for the computation of geostrophic velocity. See the README in the Stress_and_EKE directory for more information. 

Sources

• Argo floats: http://argo.ucsd.edu
• World Ocean Database: https://www.ncei.noaa.gov/products/world-ocean-database
• MEOP-CTD Database (seal profilers): https://www.meop.net/
• CDRv4 available via NSIDC: https://nsidc.org/data/G02202
• Polar Pathfinder sea ice drift data via NSIDC: https://nsidc.org/data/nsidc-0116

Version

This is a pre-production version, in that it has not yet been used with a state estimate.