Wednesday, March 13, 2019

GOES 17 and Himawari-8: coverage in the central Pacific

Some of you may remember that I wrote three posts in October 2017 of some Aero Clipper research in Guam, some of the links in these articles have expired but I am leaving these posts up. This research was done with the cooperation of the National Weather Service Weather Forecast Office in Guam. My friends at the NWS Guam WFO were wonderful, answering my questions via Facebook Messenger. I have periodically kept in touch with the Guam WFO since then.

I have been writing about GOES-17 aka GOES West recently. I was wondering if the GOES-17 coverage area reached as far west as Guam, I thought that it might but was not sure. So, I contacted them on Facebook this past Monday, March 11th) and asked them. They were. as always, very helpful. I learned that Guam and the nearby islands in the Mariana Islands are barely on the western edge of the GOES_17 coverage area. While technically visible on GOES-17 images, they get much better coverage from the Japanese Meteorological Agency's Himawari-8 satellite. I will get to those images a little later, but first some information about the Himawari-8. The Himawari-8 was launched on October 7, 2014 and flies in a geostationary orbit (22,300 miles above the Earth) at 140° East (I think). According to an October 2014 press release from the World Meteorological Association announcing the launch of Himawari-8:
Himawari-8, with the first of 16-channel imager onboard geostationary satellites with highest resolution of 0.5 km and a full disk scanning of 10 minutes,  heralds the advent of a new generation of meteorological geostationary satellites. Satellite launches in the 2015-2019 timeframe are also planned by the China Meteorological Administration, EUMETSAT, India Space Research Organization, Korea Meteorological Administration, the Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) and U.S. National Oceanic and Atmospheric Administration.
To read a brief description of the about the Himawari (AHI) Imager go here. The home page of the Meteorological Satellite Center (MSC) of the Japanese Meteorological Agency may be found here, and is chock of all kinds of information that some of you might find useful including but not limited to Himawari-8 images and a users guide. Finally, NOAA has a page dedicated to Himaware-8 images that may be found here.

Ok, back to satellite imagery of Guam and the adjoining Mariana Islands (part of Micronesia). First I asked my friends at the WFO Guam to clarify the geography of the region to provide a context for the two satellite images that I will share at the end of this article:
For the geographical stuff, some circles confirm all of the region Micronesia, but most refer to Guam as part of the Mariana Islands, Guam being the southern most; the Marshall Islands are the easternmost of Micronesia, Palau being the westernmost. All of these island regions are part of our forecasting domain.
My friends at WFO Guam told me that their forecasting area of responsibility (AOR) "as the Equator to 25N latitude, from 130E longitude to the Date Line." That is quite a large area. I did a rough image of their AOR from Google Earth. Unfortunately Google Earth does not show the international date line, but it does show the antimeridian (180° from the prime meridian) that goes through Greenwich England. The antimeridian is not co-terminus with the international date line, but it is close enough and my friends at WFO Guam said that my image from Google Earth is a good representation of their AOR.



Finally! Now for the two annotated satellite images that my friends from the WFO Guam sent to me on March 11th. I don't know date of this satellite imagery. You can easily see that Hawaii shows up in the GOES West image with Guam, the Mariana Islands and the rest of Micronesia is on the far western edge of the coverage area. Then note in the Himawari image how clearly Guam and the rest of Micronesia shows in this image.

Thanks to the NWS Guam WFO for sharing and annotating this image

Thanks to the NWS Guam WFO for sharing and annotating this image




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