The reason why the models fail is because they have in them 7 physics» mistakes, the worst of which is a claim, from meteorology, that single pyrgeometers measure a real energy flux instead of the S - B temperature signal. (bishop-hill.net)
«An absolute cavity pyrgeometer to measure the absolute outdoor longwave irradiance with traceability to international system of units, SI.» (arm.gov)
But you can't measure DLR from orbit; you need ground sites, and that fact, combined with the fact that pyrgeometers remain quite expensive, means you can't achieve the same global coverage that satellites give. (hubpages.com)