McClain recognized that international agreements for data exchange must be established whereas few currently exist. Ultimately, a plan must be developed and supported by the community for evaluating and comparing onboard and vicarious calibration information and associated uncertainty budgets. Global Geophysical Product Validation Wayne Esaias and Frank Muller-Karger, University of South Florida, presented a summary of Group 2's deliberations. Esaias stated that comparison of satellite-derived values with real in situ values is the basis for determining the accuracy of a data product in extended ranges. Error fields can also be interpreted in terms of the spatial and temporal statistics of the geophysical variables of interest.
Every mission has a very basic, minimal validation program, but none are global in scope.
Some validation programs are tuned to specific regions and sensors of interest. Esaias added that the community should use the sun photometer network to help with vicarious calibration. Esaias said there is a need to identify key regions that may have inadequate in-situ validation activities ongoing. Global survey cruises and focused field expeditions can be used to collect uninterrupted time series data on important variables. He recommended that the GSFC Wallops Flight Facility be used to obtain aerosol optical depth data.