This page summarises the common principles for generating SSES
Background
- Moving towards providing uniform uncertainty estimates for users
- Need to define common principles to do this
- These principles need to be based on quantitative analysis and be documented
- These will form the basis of the QA4EO protocol on SST validation
Quality levels
- Common scale for quality level
- Scale of 2 (worst quality) to 5 (best quality)
- Clearly defined for each producer
SSES (Single Sensor Error Statistics)
- Compliant with QA4EO. Derivation of quality indicator (i.e.SSES) to be traceable, i.e. documented and available. But… need common reference. ncludes QC of reference data
- SSES are to provide users with a common uncertainty estimate in comparison to the agreed reference source
- SSTs should be the best estimate prior to SSES production. Responsibility of the SST producer
- SSES are for users NOT for producers
- At present the reference is drifting buoys. By convention (only really global source)
- Content: A bias (not a correction term) and a standard deviation reflecting the local accuracy (at pixel) of the SST estimate. Application of SSES is consistent with the product definition (skin; sub-skin)
- Hierarchical SSES references can be used. Global stats to DRIFTING BUOYS, regional stats using other reference sources such as radiometers, the GTMBA (Tropical moored buoys) or L4 analyses
- Use of common match-up thresholds for SSES: Centre pixel clear; +/- 2 hrs (ideally 30 mins) for all sensors.
- Continuous fields preferred, i.e. no discontinuities between Quality Levels although discontinuities may be inevitable
- SSES must be free from diurnal variability and ideally estimated from night time match-ups
- A common skin to sub-skin adjustment of 0.17 K should be used
(Last Updated: 11-05-2010)