The SST processing module implements five single-algorithm SST algorithms.
Each derives SST as weighted combinations of the brightness temperatures measured in both views (nadir and oblique) and by the thermal channels (S7 to S9).
The weights are functions of the viewing geometry, water vapour loading and pixel combination.
Five different algorithms are implemented, each optimised for different operating regimes.
The same weights are used to generate estimates of the instrumental measurement noise contributions to the total SST uncertainty, in combination with estimates of the uncertainty in bias due to the presence of nearby cloud and water vapour.
Note that the following processing steps described in Calculate Exception Flags, Calculate SST values and variances and Compute pseudo-random error are repeated once for each SST parameter (N2, N3R, N3, D2, D3 SST products).
The following figure describes the successive processing sub-steps. Note that only major sub-steps are fully described.
A specific Bayesian cloud masking module over ocean pixels is implemented.