Hi Marek, re: > I have two questions, that I need to most recent update on: > # > 1. How far North, (or more general what is the geographic span in > latitude/longitude of current GOES-11(W) iand GOES-12(E)? The northern/southern most extent of any GOES scan is determined by the scanning schedule which changes. If you take into account that both GOES-East and GOES-West perform full disk scans every three hours, then you would have to say that the northern most extent is 90N and the southern most is 90S. If you are looking for the North/South extents of any particular scan, you will have to calculate the value from the scan itself. Again, the scanning is more-or-less fixed, but it does change a bit. > 2. What is the current exact geographic position of GOES-11 > and GOES-12? > Can somebody provide me that info? Geostationary satellites are, in fact, not located at a fixed longitude or latitude... GOES-12 drifts from east to west and is then moved back east by station keeping maneuvers. Likewise, GOES-11 drifts from west to east and is then moved back west by station keeping maneuvers. Both satellites drift away from 0 latitude and are returned to 0 latitude through station keeping maneuvers. Station keeping maneuvers are made because NOAA operations is required to keep its geostationary satellites within a 1 degree box centered on their nominal (intended) longitudnal locations. This is so that geostationary satellites maintain a 2 degree separation in space. The nominal location for GOES-11 is 135W longitude. The nominal location for GOES-12 is 75W longitude. NOAA posts the _forecast_ locations of GOES-10/11/12 on a NOAASIS website about once per week: http://noaasis.noaa.gov/cemscs/eqxngs.txt We have been monitoring this site since setting up a GOES-10 ingest system at the end of January, 2007. Over the course of now almost 12 months, we determined that the locations being posted on the NOAASIS website were not necessarily correct. I had an interaction Chris Wheeler, the GOES Team Lead for NOAA, back on November 28, 2007 about our observation that the values being reported were seemingly inconsistent with the requirement that geostationary satellites be kept within a one degree box centered on their nominal position. The graph I have attached illustrates the point that we made to Chris -- the indicated longitudnal position of GOES-12 far exceeded the 1 degree box requirement. Chris passed the word to appropriate people so that they could look into how the values that were being posted were generated. They apparently found some sort of a problem, since the values since the end of November, 2007 have been much more in line with what they should be. > Thanks, No worries. Cheers, Tom **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: DZP-918446 Department: Support Datastream Priority: Normal Status: Closed
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