Subsurface Salinity
 |
The global subsurface salinity observing system is vital for closure of the global hydrological cycle, estimates of oceanic evaporation and precipitation, and halosteric component of sea level change. Subsurface salinity are required to calculate in situ density and ocean freshwater transports, respectively, and coincident subsurface observations of salinity, temperature and pressure provide an estimate of the ocean geostrophic velocity. In addition, subsurface salinity is used to derive large-scale gridded climate products including ocean velocity, mixed-layer depth, density stratification, sea level and indirect subsurface ocean mixing used in many weather and climate applications. | |
| Domain: | Ocean | |
| Subdomain: | Physical | |
| Scientific Area: | Hydrosphere | |
| ECV Steward: | Eitarou Oka | |
| Products: | Sea Surface Salinity | |
Global Zonally Averaged Salinity
|
Figure: Global zonally averaged linear salinity trends [psu/50 yr] (color) with mean salinity [psu] (black contours). Source: Durack and Wijffels (2010) 50 year trends in Global Ocean Salinities and their relationship to broad-scale warming. Journal of Climate. https://doi.org/10.1175/2010JCLI3377.1 |
ECV Products and Requirements
These products and requirements reflect the Implementation Plan 2022 (GCOS-244).
The requirements are found in the complete 2022 ECVs Requirements document as well: ECV Subsurface Salinity.
| Products | Interior Salinity | |||
| Upper Ocean | Deep ocean | |||
| (*) | Unit | Values | Values | |
| Horizontal Resolution | G | km | 10 | |
| B | ||||
| T | 100 | |||
| Vertical Resolution | G | m | 1 | 1 |
| B | ||||
| T | 10 | 100 | ||
| Temporal Resolution | G | d | 1 | |
| B | ||||
| T | 30 | |||
| Timeliness | G | d | 1 | |
| B | ||||
| T | 30 | |||
| Required Measurement Uncertainty (2-sigma) | G | K | 0.01 | 0.005 |
| B | ||||
| T | 0.05 | 0.02 | ||
| Stability | G | K | ||
| B | ||||
| T | ||||
(*) Goal (G): an ideal requirement above which further improvements are not necessary. Breakthrough (B): an intermediate level between threshold and goal which, if achieved, would result in a significant improvement for the targeted application. The breakthrough value may also indicate the level at which specified uses within climate monitoring become possible. It may be appropriate to have different breakthrough values for different uses. Threshold (T): the minimum requirement to be met to ensure that data are useful
Data Sources
This list provides sources for openly accessible data sets with worldwide coverage for which metadata is available. It is curated by the respective GCOS ECV Steward(s). The list does not claim to be complete. Anyone with a suitable dataset who wishes it to be added to this list should contact the GCOS Secretariat.
- The Global Temperature and Salinity Profile Programme (GTSPP)
https://www.nodc.noaa.gov/GTSPP/access_data/index.html
- World Ocean Database, National Center for Environmental Information (NCEI)
https://www.nodc.noaa.gov/OC5/SELECT/dbsearch/dbsearch.html
- Coriolis
