AAPP V3.5 Update Release, 12/02/2003 *************************************************************************** This release contains the following files, for copying to the specified directories: avhcal.txt --> .../AAPP/sources/calibration/avhrcl/avhcal.txt calcoef.dat --> .../AAPP/sources/calibration/hirscl/calcoef.dat LUT.fdf --> .../AAPP/sources/preproc/atovpp/LUT.fdf To activate the files in your AAPP you have either 1. to copy the files also to the directories where they are read from avhcal.txt --> .../AAPP/data/calibration/coef/avhcl/avhcal.txt calcoef.dat --> .../AAPP/data/calibration/coef/hirs/calcoef.dat LUT.fdf --> .../AAPP/data/preproc/LUT.fdf or 2. to rebuild parts of the AAPP system by running INST_3 with manual input option 6 (rebuild part of the system) option 13 (avhrcl) option 6 (rebuild part of the system) option 14 (hirscl) option 6 (rebuild part of the system) option 20 (atovpp) *************************************************************************** What are the modifications? avhcal.txt : the calibration coefficients of visible AVHRR channel 3A of NOAA 16 have been modified following NOAA (see NOAA's announcement below) and the count from where on the second calibration coefficients set of the visible AVHRR channels is to be applied has been changed for NOAA 16 + 17 (see comment in the file) calcoef.dat : the calibration coeffients for the visible HIRS channel 20 of NOAA 15 + 16 have been changed LUT.fdf : the AMSU-A to HIRS mapping correction table for NOAA 17 has been updated. *************************************************************************** Topic: Visible Calibration Monthly Updates Date/Time(UTC) Message Issued: 27 January 2003; 2000 UTC Satellite(s) Involved: NOAA-16 Instrument(s) Involved: AVHRR Product(s) Involved/Affected: Channel 3A data users Date/Time(UTC) of Initial Implementation: 11 February 2003/1700 UTC Details/Specifics of Change: The Office of Research and Applications instrument scientist, Dr. Xiangqian Wu, has determined that the NOAA-16 AVHRR visible calibration coefficients (slope and intercept) need to be updated. A monthly update procedure was established for NOAA-J/14 such that updates were done on the second Tuesday of each month. We would like to do the same for the NOAA-KLM satellites beginning with NOAA-L/16. The first update is planned for the second Tuesday in February ( February 11 ). Updates for following months will occur on the second Tuesday. A notice containing the new values will be issued. Dr. Wu reports that the expected impact on the user community is as follows: "For Channel 3A, currently all counts less than 71 results in negative albedo. This error will be corrected such that all counts greater than 38 will results in positive albedo. This is the most significant change of this update. Additionally for Channel 3A, albedo for counts less than 413 will increase, typically less than 0.5% but up to 0.85% (at count=71, from 0% to 0.85%). For counts between 414 and 541, the albedo will decrease slightly, typically less than 0.2% but up to 0.48% (at count=499, from 12.09% to 11.61%). For counts greater than 542, the albedo will increase, up to 4.76% at count=959 (from 95.17% to 99.93%)." Dr. Wu has provided a more detailed explanation of why these updates are needed. This information has been added to the NOAA KLM Users' Guide in Appendix D.2. Please click on the following link to go directly to that section of the users' guide. The text begins following Table D.2-6. http://www2.ncdc.noaa.gov/docs/klm/html/d/app-d2.htm#a120902a Operations estimates that a two week notice to the user community for this initial update is sufficient. Please contact us as soon as possible if this is not the case. Test data will be made available for the February 11 update. No test data will be provided for other updates. CEMSCS users will find test level 1B data beginning with the extent, "P1S" for 1B* data and "P1B" for 1B data. Other level 1B users will find test data on the anonymous ftp site - ftp://metroweb.nesdis.noaa.gov under the subdirectory pub/ppp/NOAA16. Following are the new coefficients: NO CHANGE IN CHANNELS 1 AND 2 Channel 3A OLD NEW Slope (Low) 0.0287 0.0262 Intercept (Low) -2.043 -1.01 Slope (high) 0.1806 0.1920 Intercept (high) -78.03 -84.2 Contact Person(s) Name/Email/Phone Number for Questions: Emily.Harrod@noaa.gov/301-457-5247 ext. 117 or Robert.levin@noaa.gov/301-457-5247 ext. 124 Web site(s) that contain other relevant information (where applicable): http://noaasis.noaa.gov/NOAASIS/ml/calibration.html - NOAASIS Satellite Instrument Calibration web site http://www.oso.noaa.gov/daily-news/index.htm - SOCC morning reports http://www.osdpd.noaa.gov/PSB/PPP/PPP.html - History of level 1B notices http://www.ssd.noaa.gov/PS/SATS/messages.html - All user notices