PARMIO: A Reference Quality Model for Ocean Surface Emissivity and Backscatter from the Microwave to the Infrared

The need for a community reference quality ocean emission and reflection model for use across a broad spectral range [microwave (MW) and infrared (IR)], as well as supporting passive and active remote sensing, has been identified in various reports and international workshops. Notably, the European Commission Horizon2020 project, GAIA-CLIM (www.gaia-clim.eu), identified in Deliverable D6.11 that the lack of a reference-quality ocean emission and backscatter model was a major gap in our ability to provide absolute calibration of the satellite-based observing system. The gap was also identified by the ECMWF–JCSDA–NWPSAF all-sky assimilation workshop in December 2015 and again in February 2020 and the twenty-first meeting of the International TOVS Working Group in December 2017.

On 18 and 19 October 2022, an international science team of the International Space Science Institute (ISSI) met for the final meeting of a project started in November 2019 to develop a reference model, with the objective of it being maintained and supported, with traceable uncertainty estimation, with documented and freely available code, allowing for new science for MW to IR, and with capability to support passive and active applications (including with bidirectional reflectance distribution function, BRDF).

The meeting was split into four main parts. First, the reference model was presented with discussion of the parameterization options for its various components. Second, evaluation and validation of the model was reported in the microwave and in the infrared, for passive and active applications. Third, a fast model based on the reference model for use in data assimilation was presented. Finally, the next steps for the model development and dissemination were discussed. The reports and findings of the ISSI team are available at www.issibern.ch/teams/oceansurfemiss/, where presentations are also available. This is a short meeting report to bring the team’s activities to the attention of a wider audience.