28 September 2017

New GOES-16 Weather Satellite Will Be Turned Off for 14 Days

Posted by Dan Satterfield

Images like this from the new GOES-16 weather satellite have become a must-see for meteorologists.

GOES-16 will become the new GOES-EAST satellite late this year as the old GOES-13 is retired. We knew this move was coming but NOAA has just announced the details of the move. Currently, the new GOES-16 is over the equator south of the central U.S. At this checkout location, it can just barely see the edge of Africa, but it gives very good coverage to the western U.S. Once the move happens, the west coast will still be in view, (although at a high angle) and this will be the case until the new GOES-S is launched hopefully later next year.

So Why Move It?

This is the view from the old GOES-13 today at the GOES East position.

We need two satellites to get a good view of storms in the Pacific along with developing hurricanes in the Atlantic, so putting GOES-16 where the old GOES is now we will have continuous coverage from India through Europe and all the way to Japan using the European, U.S. and the Japanese Himawari satellites. The new position for GOES-16 will actually give us a more direct look at storms along the eastern seaboard of the U.S. this winter, with better coverage for Canada and South America.

In the past when a satellite was moved, we would still get images, but this time the imager and other equipment on GOES-16 will be put in standby mode. This means we will be relying again on the old GOES-13 ( 4 images an hour vs 12). We will also lose the greater resolution and one-minute imagery when needed. This outage will begin at 18 GMT on 30 November and continue through 11 December. It will then take three days for calibration with images back on 14 December. These dates were chosen because hurricane season ends on the 30th and the main brunt of winter is usually after mid-December.

View from GOES-16 today at the check-out location. Notice how much more of the Pacific is visible.

It has to be done and while we meteorologists will whimper for 15 days, there is no doubt that GOES-16 has already paid for itself many times over. Just ask Irma, Maria, and Harvey.

Orbital Mechanics
To move the satellite they will slow it down very slightly, which will drop it into a lower orbit that will take less than 23 hours 56 minutes and 47 seconds (It takes the Earth that time to revolve once.). This will cause it to drift slowly eastward (at a rate of 1.41 degrees of longitude per day) until another thruster fire puts it back at an altitude where it will rotate as the earth does. It will then appear to be hover over the same spot all the time, even though it’s moving over 9 km a second. It could be done more quickly but that would use more fuel.

While almost everyone has an app on their smart-phone with radar, meteorologists rely heavily on satellite imagery for forecasting. We will desperately miss this data for 15 days, but it must be done. You can get GOES-16 data free on your iPhone by going to the app store and searching for SSEC GOES UW-Madison. EVERY synoptic meteorologist I know has this app!

The official notice from NOAA is below:

Once GOES-16 reaches 75.2 degrees West on December 11, 2017, there will be three days of calibration activity. All instruments will resume nominal operations on December 14, 2017 and GOES-16 will officially become GOES-East.
There will be a three week period of overlap with GOES-13, which will remain at 75 degrees West, after GOES-16 becomes GOES-East. GOES-13 will remain on and provide data until January 2, 2018 at which time it will begin drifting to its storage location at 60 degrees West. During this period of overlap, GOES-13 GVAR will be relayed through GOES-14.
Additional information will be communicated as needed. Key points: – November 30, 2017 GOES-16 drift begins 1800 UTC – December 7, 2017 GOES-13 GVAR relay through GOES-14 begins – December 11, 2017 GOES-16 drift ends – During drift, no instrument data will be captured or distributed from ABI, GLM, EXIS, SUVI, and SEISS. MAG data will still be distributed. – During drift, GRB, DCS, HRIT/EMWIN, and SARSAT will be disabled –
December 14, 2017 GOES-16 resumes nominal operations and GOES-East operational status after calibration activities – December 14, 2017 GOES-13 GVAR available only through GOES-14 – No maneuvers / special operations during Thanksgiving and Christmas holidays – No GOES-East transition / interruption during designated Critical Weather Days –
January 2, 2018 GOES-13 will stop transmitting data – January 22, 2018 GOES-13 will reach storage location at 60 degrees West