1. 15 May 2009ACSPO v1.10 GAC1 ACSPO upgrade to v1.10 Effective Date: 04 March 2009 Sasha Ignatov, XingMing Liang, Yury Kihai, Boris Petrenko, John Stroup NOAA/NESDIS/STAR John Sapper and Denise Frey NOAA/NESDIS/OSDPD

2. 15 May 2009ACSPO v1.10 GAC2 Major upgrades in ACSPO v1.10  daily (AVHRR-based) 0.25º Reynolds SST (instead of weekly 1º)  new Community Radiative Transfer Model v1.1 (instead of r577)  CRTM built-in Wu-Smith emissivity model (instead of flat-surface Fresnel)  Plank-weighted (PW) CRTM coefficients for NOAA-17, -18, -19, and MetOp-A (for NOAA-16, ORD coefficients are still used)  Improved cloud detection -Using dynamic biases for brightness temperatures and SST filters estimated in real-time. (Before, biases were assumed to be constant) -Introducing ambient cloud filter  Day-night switch for cloud mask and SST algorithm occurs at 90° Solar Zenith Angle (instead of 85° in v1.00)

3. 15 May 2009ACSPO v1.10 GAC3 Number of Observations

4. 15 May 2009ACSPO v1.10 GAC4 During nighttime, number of OBS reduced due to -Change in day-night threshold from 85° to 90° SZA -Using ambient cloud filter Number of Observations: NIGHTTIME v1.00 v1.10

5. 15 May 2009ACSPO v1.10 GAC5 During daytime, number of OBS increased due to -Change in day-night threshold from 85° to 90° SZA (despite adding ambient cloudiness filter) Number of Observations: DAYTIME v1.00 v1.10

6. 15 May 2009ACSPO v1.10 GAC6 Cloud Mask

7. 15 May 2009ACSPO v1.10 GAC7 “Sat-Reynolds” SST anomalies in ACSPO v1.00 (3 March 2009) -Note multiple areas with negative anomalies (likely due to cloud leakage) -Cold biases at swath edges Cloud Mask Quality: ACSPO v1.00 NightDay

8. 15 May 2009ACSPO v1.10 GAC8 “Sat-Reynolds” SST anomalies in ACSPO v1.10 (4 March 2009) -Areas with negative anomalies reduced -Cold biases at swath edges reduced Cloud Mask Quality: ACSPO v1.10 NightDay

9. 15 May 2009ACSPO v1.10 GAC9 SST

10. 15 May 2009ACSPO v1.10 GAC10 -Standard Deviation of “SAT-Reynolds” SST reduced -Weekly cycle significantly reduced or removed Nighttime RMS “Sat-Reynolds” SST improved v1.00 v1.10

11. 15 May 2009ACSPO v1.10 GAC11 Daytime RMS “Sat-Reynolds” SST improved v1.00 v1.10 -Standard Deviation of “SAT-Reynolds” SST reduced -Weekly cycle significantly reduced or removed

12. 15 May 2009ACSPO v1.10 GAC12 Channel 4 Clear-Sky Brightness Temperatures

13. 15 May 2009ACSPO v1.10 GAC13 Nighttime RMS “CRTM-AVHRR” v1.00 v1.10 -Standard Deviation of “CRTM-AVHRR” BT reduced -Weekly cycle significantly reduced or removed

14. 15 May 2009ACSPO v1.10 GAC14 v1.00 v1.10 Daytime RMS “CRTM-AVHRR” -Standard Deviation of “CRTM-AVHRR” BT reduced -Weekly cycle significantly reduced or removed

15. 15 May 2009ACSPO v1.10 GAC15  Number of nighttime observations slightly reduced  Number of daytime obs slightly increased  Cloud mask improved during both day and night  AVHRR SST in v1.10 agrees better with Reynolds SST  Brightness Temperatures agree better with CRTM  For more information see http://ams.confex.com/ams/pdfpapers/143875.pdf Summary of Performance ACSPO v1.10 vs1.00

16. 15 May 2009ACSPO v1.10 GAC16  View Zenith Angle biases in retrieved SSTs have been reduced in v1.10 but we still do not recommend using SSTs beyond VZA>55º, at least for quantitative analyses. (Note that the clear-sky brightness temperatures are less subject to the angular biases.)  Residual cloud problem has been reduced in v1.10 but nighttime SSTs are still subject to residual cloud in the areas with persistent cloudiness (such as the roaring forties in the North and in the South and ITCZ). Caution should be used with the current nighttime product in those areas.  The aerosol optical depth parameters for channels 1, 2, and 3a have not been fully evaluated yet so please use caution if using these parameters Known Limitations in ACSPO v1.10

17. 15 May 2009ACSPO v1.10 GAC17  ACSPO v1.20 -Land-sea mask (1km instead of 8km) + land proximity distance -Day-night twilight zone indication -Code modularization, stability, & error handling -Resolve remaining FRAC/GAC inconsistencies  ACSPO v1.30 -Graceful degradation (Reynolds SST & GFS) -Cloud mask improvements  ACSPO v1.40 -L1b converter as front end -Further code modularization & clean-up  Level 2P, 3 and 4 development -Currently, ACSPO products are only available in L2 (swath granules) -Development of L2P (GHRSST compliant), L3 (field analysis) and L4 (weekly and monthly composites) products is currently underway Ongoing ACSPO improvements