Subject: Correction for In-Band Stray Light Problem on NOAA-17 SBUV/2 - Issued: Topic: Correction for In-Band Stray Light Problem on NOAA-17 SBUV/2 Satellite(s) Involved: NOAA-17 Instrument(s) Involved: SBUV/2 Product(s) Involved/Affected: SBUV/2 Total and Profile Ozone distributed via daily and orbital Product Master File (PMF) in Binary and BUFR format, both Version 6 and Version 8 products. Date/Time(UTC) of Initial Implementation: 26 July 2007, 1730 UTC Contact Person(s) Name/Email/Phone Number for Questions: Donna.McNamara@noaa.gov 301-763-8142 ext. 145 Web site(s) that contain other relevant information (where applicable): N/A Details/Specifics of Change: This morning we implemented a correction to N17 to reduce the affect of the in-band stray light problem that occurs in the southern hemisphere at >75 degrees solar zenith angle. Last summer we implemented a profile error code flag to indicated when this problem was occurring. The flag is 8/18 (ascending/descending) for Version 6, which is also used for the error "total ozone not available". The flag is 7/17 (ascending /descending) for Version 8, which is also used for the error "upper level profile anomaly". (Please contact us is you would like a full list of the error flags.) We have opted to continue to flag this data, although users may now find the data usable for their applications. The problem was modeled, and a correction was provided to us by SSAI contractors at NASA. A similar problem occurs with N18 in the northern hemisphere at >75 degrees solar zenith angle. The behavior of N18 has not yet been well modeled by NASA. When we receive a correction for N18, we will implement it and notify the users. Finally - Version 6 product users are reminded that we will be terminating the distribution of Version 6 products on Dec 1, 2007. Please switch to using Version 8 products as soon as possible. -- Donna P. McNamara Physical Scientist NOAA/NESDIS/OSDPD/SSD/PIB 5200 Auth Rd., Rm 510 Camp Springs MD 20746 Phone: (301)763-8142x145 Fax: (301)899-9196