Subject: Upgrades to 3B40RT, 3B41RT, 3B42RT Date: Fri, 4 Feb 2005 14:11:50 -0500 From: George Huffman To: Recipient List Suppressed:; Hello! Users are advised that an upgrade was installed after the 07Z 3 February 2005 observation time for the software used to produce the near-real-time Multi-Satellite Precipitation Analysis (MPA-RT) precipitation estimates. These data are being computed at TSDIS, where Erich Stocker deserves a great deal of credit for developing and honchoing the production end. Users of the merged microwave product (3B40RT) and the combined product (3B42RT) should see much denser microwave coverage. Users of the microwave-calibrated IR product (3B41RT) and 3B42RT should see improved control of unrealistically large areas of high rain. Please contact me if you find problems. I am appending the relevant entry from 3B4XRT_WHATSNEW at the end of this mail. The documentation has been substantially revised, so you are asked to pull fresh copies from ftp://meso912.gsfc.nasa.gov/pub/agnes/huffman/rt_examples/docs . As you will see from the file dates, the following have been revised: 3B40RT_README 3B40RT_README.ipwg 3B41RT_README 3B41RT_README.ipwg 3B42RT_README 3B42RT_README.ipwg 3B4XRT_README 3B4XRT_WHATSNEW 3B4XRT_doc Most ordinary users will likely only need 3B4XRT_README and 3B4XRT_doc . Recall that the root URL for these data is the anonymous ftp site: ftp://trmmopen.gsfc.nasa.gov/pub/merged The research version of the MPA, the Version 6 TRMM algorithm 3B42, has been reprocessed through the year 2000, and continues at a rate of 5-8 times wall-clock speed. Sometime this month it is expected that 3B42 will start to be applied to current data, in addition to the reprocessing activity. Version 5 3B42 is still available from the Goddard DAAC. Finally, you received this message because of prior discussions or e-mails. Please reply if you wish to be removed from the list or if you know of a colleague who wishes to be put on the list. Regards, GJH DETAILS: Version 1.3 was instituted as of 08Z 3 February 2005, providing several important upgrades: * Precipitation estimates from the AMSR-E and the 3 AMSU-B sensors are incorporated in the HQ product (3B40RT), which nearly doubles the coverage by HQ data in the latitude band 50 deg N-S from ~45% to nearly 80%. * Inter-satellite calibration in the HQ product is climatological, reducing the real-time computational load and preparing for the eventual termination of TRMM. The calibrations of AMSU-B and AMSR-E to TMI each have one set of coefficients for land and a separate set for ocean, while SSM/I uses one et for land and 5 for ocean, covering the latitude bands 90-30 deg. S, 30-10 deg. S, 10 deg. S-N, 10-30 deg. N, and 30-90 deg. N. AMSR-E uses a 2-month set of match-ups to ensure sufficient sampling, while all of the others work with single-month accumulations. The AMSR-E and AMSU-B coefficients apply to the entire year, while SSM/I uses a separate set for each season. * VAR coefficients are recomputed every 3 hr to better control unrealistically high VAR estimates when a batch of unusually cold IR Tb's are encountered in a region. The calculation is now done with all of the HQ-IR match-ups observed in the previous 5 pentads, plus whatever match-ups have occurred in the current pentad. -- George J. Huffman, Ph.D. (Voice) +1 301-614-6308 Sci. Sys. & Appl., Inc. (FAX) +1 301-614-5492 NASA/GSFC Code 613.1 (Email) huffman@agnes.gsfc.nasa.gov Greenbelt, MD 20771 USA (Office) Bld. 33 Room C410