Sustainability of HIRS OLR Climate Data Record—From Research to Operation

Outgoing longwave radiation (OLR) at the top of the atmosphere is a component of the radiation budget for the earth/atmospheric system, and it is also one of the key parameters for climate monitoring. Long-term OLR observation is used to evaluate the global changes and to assess the fidelity of the re-analyses and forecasts from numerical weather/climate prediction models. Accurate OLR can be estimated from High-resolution Infrared Radiation Sounder (HIRS) radiance observations with the multispectral regression model first developed by Ellingson et al. (1989). NOAA/NESDIS implemented this algorithm and has been generating the HIRS OLR product operationally since 1998. A suite of procedures is established to generate HIRS OLR climate data record (CDR) following recent researches sponsored by NPOESS Risk Reduction and NOAA Scientific Data Stewardship projects. A 30-year (1979-2008) continuous HIRS OLR CDR with global coverage has been produced and released. We are currently constructing the prototype operational production system and will soon start the transition towards sustainable operation at the National Climate Data Center (NCDC). In this paper, we will discuss the results of the HIRS OLR CDR product validation, the maturity and ongoing improvement of the methodologies, and the requirements for achieving sustainable OLR CDR product – emphasizing the pre-scoped reprocessing capability, continuing product validation and verification activities, and future sounder instruments. The conformation to relevant standards such as NetCDF-4 data format, Climate and Forecast metadata definitions, and software development, will also be addressed.