March 02, 2018

The New West Coast Weather Satellite is Launched

Every western U.S. weather enthusiast should be pleased with the successful launch yesterday of the GOES-S satellite, a major improvement upon the current NOAA/NWS weather satellite, GOES-15.  I mean really better.

By the way, GOES stands for Geostationary Operational Environmental Satellite--you can impress your friends with such information.

GOES-S, built by Lockheed Martin, was launched around 2 PM PST from Cape Kennedy using an United Launch Alliance (ULA) Atlas-5 rocket.

Within a few weeks GOES-S will move into a stable geostationary orbit 22,300 miles (35,800 kilometers) above the earth's equator, an orbit that allows it to rotate with the same angular velocity as the earth, thus staying above a fixed location with respect to the earth's surface. It's final position, as GOES-West, will be around 135W longitude, giving it a good view of the eastern Pacific and western North America.

There are five geostationary operational weather satellites (see figure).  Two belong to the US (GOES E and W), one is Japanese (GMS), one Indian (INSAT) and one is European (METEOSAT).    Between then we have total, continuous coverage from the equator to roughly 70N and 70S.   GOES-E has already been replaced with the new technology it is our turn.

 Why are we so excited about GOES-S (which will become GOES-17 when operational)?   Well, for many reasons.

First, it has much higher resolution sensors.  

In the visible part of the spectrum, the pixels are .5 km on a side for the new satellite versus 1 km for the old.  That means sharper, more detail imagery.  Here is an example for a hurricane eye (left is what we have now, right is what we will have).

The other wavelengths are also better, going from 4-km to 2-km on a side.  That means the infrared pictures you see most of the time will be much sharper.

GOES-S views in two wavelengths in the visible, which allows it to produce color pictures, compared to the black and white imagery of the old satellite (see example).

And the new satellite can scan the planet much faster.  For example, GOES-S will produce a new image 12 times per hour, versus 4 times per hour for the current satellite.  For fast changing weather situations, high time resolution is very informative, particularly for severe weather situations.

The new satellite also has the ability to detect lightning from space, using very sensitive photo sensors.  To illustrate, here is the lightning detected from space during Hurricane Harvey from the new GOES-E satellite:

Now, I have only described a few of the amazing capabilities of the new GOES satellite.  It will take about 6 months to check it out and to complete necessary calibration chores, but next winter season we should have a much more detailed and comprehensive view of eastern Pacific weather from space.

Finally, let me note that the weather satellite like this don't come cheap, with each satellite costing about 350 million dollars, plus launch and monitoring costs.  Weather satellites are critical for weather prediction and monitoring of our planet, and weather forecasting would be much less skillful without them.


  1. Great news, and I'm hoping that we'll also get another radar station in the aforementioned "dead zone" along the coast.

  2. Beautiful visible light 4km image picture of snow cover today.Color pics from the new satellite will be fantastic!

  3. How will the budget cuts being bandied around effect future weather satellite launches?


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