CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS EDR Algorithms for the Cross-track Infrared Sounder Xu Liu Atmospheric Environmental research, Inc. 131 HartwellAve, Lexington, Ma Contact: and Ronald J. Glumb, Christopher E. Lietzke and Joseph P. Predina ITT Industries, ITT Aerospace/Communications, 1919 West Cook Road, P.O. Box 3700, Fort Wayne, IN 46801, USA Contact:

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 2 CrIMSS EDR Products CrIS EDR Algorithm p s (NWP) Surface Map Climateology (first guess)

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 3 AMSU/MHS Channels Used (ATMS to replace AMSU/MHS) CrIS EDR Algorithm

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 4 CrIS Channels Used Channels Excluded During MW/IR Retrieval –Ozone Band from 950 cm-1 to 1095 cm-1 –Trace gas channels –Low information content channels (channel selection) –Good results using only 400, 300 and 150 channels Special High Information Content Channels Used –709.5 cm-1 to 746 cm-1 for cloud parameter  estimation and Principle Component Analysis (PCA) for estimating number of cloud formations –2190 cm-1 to 2250 cm-1 for cloud parameter  estimation CrIS EDR Algorithm

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 5 Fast Forward Model Optimal Spectral Sampling (OSS) –Developed at Atmospheric Environmental Research (AER) –Fast and accurate (validated against Line-by-line models) –Can model non-localized Instrument Line Shape (ILS) –Computes Jacobian efficiently –Accurate treatment of reflective radiation from surface –Both MW and IR versions developed CrIS EDR Algorithm Benchmarked against AIRS fast forward model in 1999……… OSS > 20 times faster OSS > 40 times faster when including Jacobians Only 20% Speed Penalty when Modeling sinc vs. Blackman-Harris Instrument ILS

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 6 Retrieval Methodology (Rogers, 1976) CrIS EDR Algorithm Observed Radiance Calculated Radiance Matrix of Partial Derivatives of y i With Respect to x Retrieved Variable Error Covariance Matrix of Background Error Covariance Matrix of Measurement Background Temp/moisture/ Emissivity/ Reflectivity/ etc. EOF Form Used General Form Used EOF Form Has Much Smaller Dimension & Is Modified to Handle Nonlinear Case

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 7 Retrieved Parameters CrIS EDR Algorithm

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 8 CrIMSS Retrieval Process (1 of 6) Initialization –Load instrument specifications (AMSU, MHS, CrIS frequencies, Noise, etc.) –Load climatoligical atmospheric data base –Load surface background data base (Mean profiles, error covariance matrices) –Load OSS parameters (Optical depth tables) –Load solar spectrum –Load topography & land/ocean mask CrIS EDR Algorithm Fast Forward Model Parameters Indexed Every 10 Degree of Temperature GTOPO30 Digital Elevation Map, land/ocean mask Used for First Guess

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 9 CrIMSS Retrieval Process (2 of 6) Preprocessing –Test for precipitation –Compute surface pressure from NWP data –Test for surface type Land Ocean Ice Snow Coast: ocean/land Coast: ice/snow –Choose Background by Surface type & mix with emissivity information CrIS EDR Algorithm Land/ocean maps & MW Brightness Temperature 31, 50, 89 & 23 GHz MW Land Emissivity per Grody model (Grody, 1988) MW Ocean Emissivity per Wilheit model (Wilheit, 1979) Interpolated in Time and Space

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 10 CrIMSS Retrieval Process (3 of 6) Microwave Only Retrieval –Average radiances from 9 MHS FOVs –Execute OSS fast forward model based upon climatology first guess –Perform inversion & update first guess profile –Calculate new radiances using OSS –Test for convergence –Continue iteration if convergence criteria not met CrIS EDR Algorithm

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 11 CrIMSS Retrieval Process (4 of 6) CrIS EDR Algorithm Scene Classification –Purpose Maximize # of good retrievals within a field of regard (FOR) Optimize an FOV clustering strategy for treatment of clouds and use of cloud clearing algorithm –Method Form matrix of 9 FOVs by 62 IR channels in the spectral region from 709 to 748 cm -1 Analyze for up to 9 principle components Determine number of cloud formations present from PCA analysis & 2 statistical tests Cluster minimum number of FOVs needed to perform cloud clearing principle components indicating 2 cloud formations Example of PCA Analysis

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 12 CrIMSS Retrieval Process (5 of 6) CrIS EDR Algorithm Combined MW/IR Retrieval –Uses MW retrieval as first guess (profiles, surface, cloud parameters) –Modified Maximum Likelihood Method for nonlinear retrieval –Dynamically adjust channel weights to improve convergence and stability –Cloud clearing parameter  estimated each iteration –FOVs averaged above 80 mbar –Test for convergence –Continue iterations if convergence criteria not met

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 13 CrIMSS Retrieval Process (6 of 6) Quality Control –If normalized  2 > 1.0 for the retrieval, then retrieval is not reported –If MW radiances after MW/IR retrieval differ by more than 3 K from observed radiances, then entire retrieval rejected –If MW retrieval and MW/IR retrieval differ by more than 3 K, then the MW/IR retrieval is rejected –If difference between cloud cleared CrIMSS radiances and VIIRS cloud free radiance is greater than 2 k, then retrieval is suspect CrIS EDR Algorithm

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 14 Performance for Various Levels of Channel Selection CrIS EDR Algorithm

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 15 CrIMSS Projected Performance CrIS EDR Algorithm Based on Global Average

CrIS Use or disclosure of data contained on this sheet is subject to NPOESS Program restrictions. ITT INDUSTRIES AER BOMEM BALL DRS 16 Expected Improvement Over HIRS (RMS Uncertainty, Global Average Basis) CrIS EDR Algorithm CrIS HIRS CrIS HIRS