Slide 1

On the Development of GOES-R Longwave Earth Radiation Budget Products Hai-Tien Lee (1) & Istvan Laszlo (2) (1) CICS/ESSIC-NOAA, University of Maryland (2) NOAA/NESDIS/STAR GOES-R 2007 Annual MeetingLansdowne, VA, May 15-18, 2007 Acknowledgments: Nicolas Clerbaux, Steven Dewitte (RMI, Belgium), Jacqueline Russell (Imperial College, UK), GERB and SEVIRI Teams, Fred Rose & CERES Team, and NASA Langley Data Center. GOES-R Risk Reduction and AWG Projects. Slide 2 2 LW Earth Radiation Budget Parameters Top of the atmosphere Outgoing Longwave Radiation (OLR) - Physical-based multi-spectral regression model Surface Downward Longwave Radiation (DLW) - Physical-based multi-spectral non-linear regression model, physical-based statistical parameterization Surface Upward Longwave Radiation (ULW) - physical method Slide 3 3 Algorithm Heritage Slide 4 4 HIRS OLR Climate Data Record 1979 - 2003 (Lee et al., 2007) HIRS OLR Climate Data Record in excellent agreement with broadband measurements. HIRS OLR Validation (Ellingson et al., 1994) HIRS OLR is Operational since 1998. Tropical Mean HIRS Multi-spectral OLR Algorithm N i = channel i radiance = local zenith angle a i = regression coefficient Slide 5 5 SEVIRI OLR Validation Slide 6 6 Methods and Issues for Measurements Collocation Slide 7 7 OLR Validation Reference CERES SSF OLR Daytime Nighttime June 2004 Slide 8 8 SEVIRI-CERES OLR Differences June 2004 Negative DifferencesPositive Differences Day Night Highly variable cloud, e.g., ITCZ, is a scene that the measurements were typically mismatched - producing both large positive and negative random errors. Slide 9 9 Space and Time Collocation Observation Time in 15 min. window View zenith angle matched (azimuth is not!) Spatial Homogeneity SEVIRI radiances averaged for a 3x3-pixel target (red, 9km at nadir) collocates with a CERES footprint (yellow, 20km at nadir). Slide 10 10 Collocated, VZA-matched SEVIRI and CERES OLR June 2004 Night-time How do the observation time differences and the varying spatial homogeneity affect the validation results? Mean OLR DiffStd OLR Diff Homogeneity Index Bins Threshold of Time diff (sec) Slide 11 11 Threshold and Absolute Homogeneity Statistics for points < thresholdStatistics for points for index bins LimitRange Slide 12 12 Validation Results Slide 13 13 SEVIRI Model Comparison June 21-27 and Dec. 11-17, 2004 Meteosat8 full disk domain CERES SSF FM1/2 (Ed2b), FM3/4 (Ed1b) View zenith angle matched (