The Group for High Resolution Sea Surface Temperature (GHRSST) and its use of ship SST
Creators: name: Beggs, Helen,
name: Wimmer, Werenfrid
name: O'Carroll, Anne
name: Bearzotti, Chiara
name: Vazquez-Cuervo, Jorge
name: Zhang, Haifeng
Publisher: name: Zenodo
Year: 2023

description: Beggs, Helen, Werenfrid Wimmer, Anne O'Carroll, Chiara Bearzotti, Jorge Vazquez-Cuervo, Haifeng Zhang and the GHRSST Science Team Presented at the 12th Session of the Ship Observation Team, 15th – 18th May 2023, Melbourne (Hybrid), Australia. The Group for High Resolution Sea Surface Temperature (GHRSST: https://www.ghrsst.org) is an open international science group that coordinates research and operational developments in satellite-derived sea surface temperature (SST) and promotes the application of satellites for monitoring SST. It achieves these aims by enabling SST data producers, users and scientists to collaborate within an agreed framework of best practices. In-situ SST data have long been used to ground-truth satellite-derived SST observations, including within GHRSST. SST at centimetres to several metres depth ("SSTdepth") measured by drifting buoys, moorings and Argo floats are widely used by meteorological, academic and space agencies for bias-correction and verification of satellite SST products. Well-calibrated and high-frequency observations of ship SSTdepth, such as those produced by the Australian Integrated Marine Observing System (IMOS), research vessels or Saildrones, are also used by GHRSST to validate satellite SST products and are particularly useful in coastal highly dynamic regions to verify their feature resolution. In addition, near real-time observations of SSTdepth from ships of opportunity, available from the Global Telecommunication System (GTS), are routinely ingested into most operational SST analyses used for Numerical Weather Prediction and other applications. They often provide the only SST observations in near-coastal, cloudy regions lacking in other in-situ and satellite SST observations and are therefore valuable. It is requested that meteorological and oceanographic agencies focus on improving the quality and uncertainty of ship SST data supplied to the GTS, to improve the accuracy of SST analyses and climate data records, particularly in near-coastal regions. The most valuable SST observations for satellite verification, however, are those provided by infrared radiometers on ships of opportunity that measure the temperature in the thermal "skin" at around 10 microns depth ("SSTskin"), the same depths as measured by infrared radiometers on satellites. GHRSST uses the fiducial ship SSTskin observations from the International Shipborne Radiometer Network (ships4sst.org) for SI traceable verification of satellite SST products. The international network of universities and agencies deploy autonomous infrared SST radiometers on ships of opportunity (ferries, cruise ships and research vessels). Delayed mode SSTskin data are processed after cruises with all pre- and post-cruise calibration information, quality-controlled, and total uncertainties are estimated. The data are converted to the in-situ radiometer format (L2R), based on the GHRSST level 2 satellite SST (L2P) format, and uploaded to the Ships4SST database, hosted by Ifremer. From here, they are available via ships4sst.org for users to access for satellite SST verification. See https://ships4sst.org for how to join meetings and become involved. Or visit the GHRSST website for this specific task team: https://www.ghrsst.org/about-ghrsst/task-teams/task-team-on-shipborne-radiometry/