Validation of CrIMSS sounding products of Cloud contamination and angle dependency Zhenglong Li, Jun Li, and Yue Li University of Wisconsin - Madison

Outline CrIMSS sounding products are affected by – cloud contamination – viewing angle Validation using – ECMWF – CrIS radiance observations

Pre-processing VIIRS Cloud fraction – VIIRS Cloud fraction: collocation of VIIRS cloud mask geolocation with CrIS SDR geolocation – Cloud fraction is calculated for each CrIS FOV by counting the cloudy VIIRS pixels Simulated CrIS radiance by SARTA – CrIMSS T/Q/Tskin – CrIMSS(IP) O3 – UW hyperspectral land surface emissivity

CrIMSS overall quality flag - Ascending Most of the retrievals are microwave only; thus may use CrIS spectrum validate CrIMSS sounding Poor retrievals in high latitude areas

CrIS 11-micron Tb - Ascending Exclude FORs with poor retrievals Compare with CrIS cloud fraction in next slide

CrIS cloud fraction - Ascending Exclude FORs with poor retrievals Consistent with CrIS BT image in previous slide

Tskin: CrIMSS-ECMWF - Ascending Exclude FORs with poor retrievals Land is more prone to emissivity uncertainty Appears to be geographically related with clouds Appears to be related to satellite viewing angle between 40 S and 40 N

CrIS cloud fraction - Ascending Exclude FORs with poor retrievals Compare with T500 diff in next slide

T 500 hPa: CrIMSS-ECMWF - Ascending Exclude FORs with poor retrievals Appears to be geographically related with clouds in southern hemisphere Appears to be related to satellite viewing angle between 40 S and 40 N

CrIMSS overall quality flag - Descending Most of the retrievals are microwave only; thus may use CrIS spectrum validate CrIMSS sounding Poor retrievals in high latitude areas

CrIS 11-micron Tb - Descending Exclude FORs with poor retrievals Compare with CrIS cloud fraction in next slide

CrIS cloud fraction - Descending Exclude FORs with poor retrievals Consistent with CrIS BT image in previous slide

Tskin: CrIMSS-ECMWF - Descending Exclude FORs with poor retrievals Appears to be geographically related with clouds Appears to be related to satellite viewing angle between 40 S and 40 N

CrIS cloud fraction - Descending Exclude FORs with poor retrievals Compare with T500 diff in next slide

T 500 hPa: CrIMSS-ECMWF - Descending Exclude FORs with poor retrievals Appears to be geographically related with clouds in southern hemisphere Appears to be related to satellite viewing angle between 40 S and 40 N

Clouds affect CrIMSS sounding - Ascending CF: cloud fraction Dash lines: bias Solid lines: STD Dev Clouds affect both precisions and accuracies, both T and Q Clouds affect precisions slightly more than accuracies Reference: ECMWF

Clouds affect CrIMSS sounding - Descending CF: cloud fraction Dash lines: bias Solid lines: STD Dev Clouds affect both precisions and accuracies, both T and Q Clouds affect precisions slightly more than accuracies Reference: ECMWF

Angle affects CrIMSS sounding - Ascending ANG: satellite viewing angle Dash lines: bias Solid lines: STD Dev Angle affects T more than Q Angle affects accuracies more than precisions All sky Reference: ECMWF

Angle affects CrIMSS sounding - Descending ANG: satellite viewing angle Dash lines: bias Solid lines: STD Dev Angle affects T more than Q Angle affects accuracies more than precisions Reference: ECMWF All sky

Angle affects CrIMSS sounding - Ascending Reference: CrIS radiance obs Clear sky Ocean only Lower atmosphere Upper atmosphere Combination of T/ε angle dependency T angle dependency Mean difference between CrIS obs and calc An example of CrIS Tb spectrum in longwave CO2 band

Angle affects CrIMSS sounding - Descending Reference: CrIS radiance obs Clear sky Ocean only Lower atmosphere Upper atmosphere Combination of T/ε angle dependency T angle dependency An example of CrIS Tb spectrum in longwave CO2 band Mean difference between CrIS obs and calc

Summary CrIMSS sounding products agree with ECMWF reasonably well Cloud presence slightly degrades the CrIMSS sounding products, both temperature and moisture, and both precisions and accuracies CrIMSS temperature sounding products are slightly degraded with larger satellite viewing angle; more temperature bias Suggest to add quality flags of cloud fraction and angle dependency