NGAS CrIMSS EDR Algorithm Assessment and Code/LUT Update Recommendation

1. NGAS CrIMSS EDR Algorithm Assessment and Code/LUT Update Recommendation June 26, 2012 NPP Support CLIN 5050

2. CrIMSS EDR Retrieval and ATMS SDR Bias Correction Assessment • Evaluating ATMS bias correction • Bias correction based on NaRC estimates • Accuracy evaluated by examination of • MW radiance residuals from the second stage IR+MW combined retrieval • MW-Only retrieval vs IR retrieval vs ECMWF Truth • Radiance residual errors attributed to inconsistency between IR and MW radiances/RTMs • Residual differences need to be tuned out to pass quality control • Low convergence rate for IR+MW combined retreival mostly caused by inconsistency in radiances/RTMs • Explore feasibility of estimating ATMS SDR/RTM biases using IR retrieval results • Clear converged retrievals only • Non-surface channels only • Surface channels need to have emissivity problem fixed first • Preliminary results seem to be mixed

3. MW Radiance Residuals: CH 15 MW Radiance Residual: MW+IR Retrieval MW Radiance Residual: MW-Only Retrieval

4. MW Radiance Residuals: CH 18 MW Radiance Residual: MW+IR Retrieval MW Radiance Residual: MW-Only Retrieval

5. Comparison of MW and IR Retrieval Against ECMWF Truth: AVTP Daytime

6. Comparison of MW and IR Retrieval Against ECMWF Truth: AVTP Nighttime

7. Comparison of MW and IR Retrieval Against ECMWF Truth: AVMP Daytime

8. Comparison of MW and IR Retrieval Against ECMWF Truth: AVMP Nighttime

9. ATMS SDR Bias Estimates: Temperature Sounding Channels 4-15 CH5 CH4 CH6 CH7 CH11 CH8 CH9 CH10 CH12 CH13 CH15 CH14 Red: Estimated MW SDR Bias from IR – no ATMS tuning Blue: Estimated MW SDR Bias from IR – with ATMS tuning Black: ATMS SDR bias correction

10. ATMS SDR Bias Estimates: Moisture Sounding Channels 17-22 CH18 CH17 CH19 CH22 CH20 CH21 Red: Estimated MW SDR Bias from IR – no ATMS tuning Blue: Estimated MW SDR Bias from IR – with ATMS tuning Black: ATMS SDR bias correction

11. Surface Channels CH 1 CH 2 CH 3 CH 16

12. Build MX6.3 Timeline and Recommendation • Already missed MX6-Mx6.2, and next available build is MX6.3 • Cut-off date for DPA/DPE AERB approval is 7/27/12 • Effective cut-off date for submission to DPE/DPA is 7/19/12 (one week before AERB) • All changes need to be verified on G-ADA • Updated LUTs need to be converted into operational format • Code and LUT changes need to be implemented and tested using operational code on G-ADA • Submission package includes code/LUT updates, performance test report, functional test input and out files, DPE code/LUT changes forms • NGAS Recommendation • Given the schedule constraint, NGAS recommend to submit to DPA/DPE a change request that includes code change for ATMS bias correction, adding a new LUT (ATMS scan-dependent biases), and updating the climatology LUT (MW emissivity) • Other candidates for LUT update: CrIS sensor error LUTandCrIS RTM bias LUT?

13. CrIMSS Algorithm Software Code Update • Add a functionality to perform ATMS SDR scan dependent bias correction • Introduce a new LUT: ATMS SDR bias correction table • The new LUT will be derived from Obs-Cal differences for every channel/scan position, and have a size of (30x22) • It can be initially populated with LaRC’s estimates • Add code to read in the LUT and remove the bias from the observed ATMS SDRs Do IFOR=1,30 Do ICH=1,22 TB_Corrected (IFOR,ICH)= TB_SDR(IFOR,ICH) – ATMS_BIAS(IFOR, ICH) ENDDO ENDDO • For the delivery, the LUT will be in acsii format, with hard-coded file name and path. IDPS will be requested to put the LUT in DMS structure and develop the corresponding I/O interface to properly load the LUT • Code affected: calcCrimssProfiles.f • Documentation affected: CrIMSS ATBD, CrIMSS OAD, Common Data Format Control Book Vol. VIII • These documents need to be updated by their “owners” . The delivery package will not include the updated documents - NGAS no longer own these documents

14. CrIMSS Algorithm Software LUT Update • Updating CrIMSS LUTs to improve EDR performance • Candidates for MX6.3 Implementation • Climatology LUT (only MW emissivity affected) • Low MW-only convergence (~50%) believed to be caused by MW emissivity a priori not consistent with the observations over land. LaRC’s new LUT has significantly improved MW-Only convergence, and is a good candidate for updating this table • The team may want to consider MW emissivity retrieval using offline code to refine the LUT later • CrIS sensor error LUT • At-launch LUT is too conservative, and needs to be refined to reduce percentage of cloudy scenes being mis-classified as clear • CrIS SDR team and NGAS have post-launch estimates of the noise component of the LUT • Recommend the team test performance impact on EDR quality/convergence • CrIS RTM bias correction LUT • At-launch LUT based on IASI proxy data • Large inconsistency between MW and IR for moisture channels – suspect of IR RTM tuning effects • NGAS is generating simulated radiance from ECMWF, and is ready to tune this LUT • Once verified for positive impact, NG can convert these LUTs into ops format and test on G-ADA for submission to DPE/DPA