Nighttime weather satellite interruption

[David Wolfson]

Why is data from the GOES satellite interrupted for several hours in the morning?

 

[Jeff Snyder]

It's the GOES eclipse:

What is a satellite eclipse period?
Since GOES is in a geosynchronous orbit, the sun will yearly traverse a +/- 23.5 degree angle perpendicular to the Earth's equator (GOES orbit plane). As a result, near the Vernal and Autumnal Equinoxes the Earth disk will periodically occult the sun, from a GOES perspective. Essentially, there are two eclipse seasons for each GOES spacecraft. Each eclipse season spans a 48-day period, symmetric around the equinox and the sun occultation lasts for a maximum of 72 minutes/day during the equinox. Each GOES spacecraft utilizes a solar array that converts sunlight into electricity in order to power the satellite. Each day during the eclipse season the sun is blocked by the Earth and sunlight is not available to the GOES solar array. Therefore, the energy needed to power the instruments is not available and the instruments are powered off. There is typically a 0-3 hour outage of imagery each day as GOES progresses through eclipse season. The maximum outage of 3 hours will occur at or near the equinox.

--> NWS Southern Region GOES Satellite FAQs

You can view the schedule of the nightly outage at http://www.ssd.noaa.gov/PS/SATS/eclipse.html .

 

[Gregg Gallina]

To piggyback... GOES-13 (currently over 100W) will have enough stored power to its batteries to not have to go into eclipse. However...there will still be individual image dropouts due to direct sunlight incursion where the image will not be scanned to protect the sensor from overload called Keep out Zones (KOZ). There will be plenty of those come this time of year...but overall less missed images than current Goes series.

 

[David Wolfson]

Thanks for the good information setting me straight!