Assessing the quality of sea surface temperature observations from drifting buoys and ships on a platform‐by‐platform basis

[1] This study investigates how the quality of sea surface temperature (SST) observationsmade by drifting buoys ( drifters) and ships for 1996–2010 can be improved through retrospective quality control (QC) against a reference field. The observationsused are a blend of delayed mode data taken from the International Comprehensive Ocean-Atmosphere Data Set(versions 2.0 and 2.5) and real time data obtained from the Global Telecommunication System. A comparison of drifterand ship measurements on a platform-by-platform basis to high-quality SST estimates from the Along track scanning radiometer Reprocessing for Climate (ARC) project reveals drifter observationsare generally of good quality but frequently suffer from gross errors, whilst ship observationsare generally of worse quality and show a diverse range of measurement errors. QC procedures are developed which similarly assess drifterand ship SST observationsthrough comparison with the Met Office Operational SST and Sea Ice Analysis (OSTIA). These procedures make use of seasonal background error variance estimates now available for OSTIA. Drifter observationsdisplaying some commonly observedgross errors are flagged and ship callsigns whose observationsare deemed unreliable are blacklisted. Validation of the QC outcomes against ARC and Argodemonstrates that this retrospective QC improves the quality of drifterand ship observations, though some limitations are discussed.