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  Time series definitions

Defined regions

In order to analyse and validate the bulk SSTs estimated at the Met Office from brightness temperatures recorded by the AATSR instrument in near-real time, various time series are compiled for the following regions:

Global: 180W to 180E, 90S to 90N
UK waters: 20W to 10E, 40N to 60N
Elnino: 150W to 90W, 5S to 5N
Tropics: 180W to 180E, 20S to 20N
West Pacific: 140E to 180E, 10S to 10N
North Atlantic: 40W to 15W, 40N to 60N

Only SSTs which pass certain quality control tests are included in these analyses: they must be deemed to not be cloud contaminated, from threshold tests against the number of pixels contributing to each cell, and from threshold tests against climate datasets. Checks are also performed to test for the presence of ice in the cell, with positive results rejected. Finally, a mean global offset is added to the SST, differing for 2-channel and 3-channel retrievals, to correct for mean biases observed between the retrieval algorithms and against in situ SST data.

Mean AATSR sea surface temperatures

The daily number of global AATSR skin SSTs within the ESA Meteo product are displayed, including the daily number of 2-channel daytime and 3-channel night-time SSTs.

The 10 arc minute AATSR sea surface temperatures are averaged to a 1 degree resolution. Time series for the mean and number of 1 degree SSTs are displayed for each of the defined regions.

The mean SST plots display both skin SST and bulk SST (corrected for the skin effect) observations estimated at the Met Office. using a dual-view, 2-channel retrieval algorithm at day and night, and a dual-view, 3-channel retrieval algorithm for night time observations only. The bulk SSTs are included when a good skin delta-T (the modelled difference between the skin and bulk SSTs) has been calculated.

Additionally, time series of the skin SST within the Meteo product minus the skin SST estimated at the Met Office, and of the 2-channel bulk SST minus the Met Office's NWP SST are displayed.

Comparisons with HadISST1

The bulk SSTs estimated at the Met Office for AATSR are compared with near-real time HadISST1 (Hadley Centre Sea-Ice and Sea Surface Temperature) data. HadISST1 data is supplied on a spatial resolution of 1 degree over the whole globe by the Hadley Centre on a monthly basis and originates from insitu and AVHRR (Advanced Very High Resolution Radiometer) SST observations. The near-real time monthly HadISST1 analysis is available a month after the end of the analysis month.

More information on Met Office climate datasets

Time series are produced for comparisons against the bulk SST derived at the Met Office and additionally against the ESA supplied skin SST, for the defined regions.

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