(WROC-TV Rochester, NY)- There’s so much to see if you just stop for a minute and take a closer look.
It may sound trite, but when it comes to the science of meteorology, a satellite picture can truly say “a thousand words”.
When watching the weather report, it’s easy to take for granted the graphical presentation that’s delivered. To that end, the resolution capability of today’s weather satellites is something that can easily be taken for granted as well, given the rapid advancements in technology over a very short time frame.
To appreciate where we are with this, you have to remember where we were, and how we started.
When I started out as a meteorologist fresh out of Vermont’s Lyndon State College twenty-one years ago, the resolution capability of the operational GOES weather satellite (GOES stands for Geostationary Operational Environmental Satellite) paled in comparison to what we have today. We were lucky to have imagery that was twelve kilometers in resolution, which twenty years ago was an incredible improvement, considering the first weather satellites were television cameras sent into space in 1960.
That’s right: television camera technology was used for the first weather satellite. The achievement of launching that satellite, known as TIROS-1, was a milestone in meteorology. For the first time, it was possible to view large scale cloud patterns in their totality, and from this, identify storm regions. The satellite provided the first long-term observations of a developing storm from orbit. In the case of TIROS-1, the satellite tracked the disintegration of a large storm off the coast of Bermuda over the course of four days. That was something only that could be dreamed about before its time!
Fast forward to 2021, and the amount of detail that can be picked up is truly remarkable. The third generation of GOES, known as GOES-R, can look at our atmosphere with a spatial resolution of one half of a kilometer. This resolution is important as meteorologists use the imagery to determine cloud shapes, heights, and type. Changes in these cloud properties, along with cloud movement, provide valuable information to weather forecasters to determine what is happening right now and to determine what will happen in the days, hours, and now thanks to the higher resolutions, even minutes ahead.
And while spatial resolutions have changed, and have changed for the better, the premise as to how the GOES system works has pretty much stayed the same. The sensors onboard the satellites react to two basic types of radiant energy: visible and infrared.
The first is visible light. Visible light is produced by the sun and reflected off of Earth’s surfaces and clouds back up to the satellite. Darker ground surfaces (dense areas of forest for example), along with water bodies in clear areas, reflect little sunlight back up to space, and therefore appear dark or grey. All clouds look white to the sensor as they do to our eyes. The detail of ONE cloud during the day is evident on this visible satellite imagery. Unfortunately, it is only available during the day.
The image you see in this blog is today’s visible satellite image. You can clearly see the darker bodies of the Great Lakes, the land that is dark where clear sky prevails, and the clouds that billowed up with the heating of the day over the higher terrain. It amounts to nothing short of a piece of meteorological artistry!
The second type of radiant energy detected is heat energy, or infrared energy. The sensors on board the satellite detect the infrared or heat energy given off by the Earth and detect those that are within range of the temperatures of Earth’s land and water surfaces. The intensity of the energy is related to the specific temperature of the surface. Because the Earth AND the atmosphere emit energy by day and by night, this type of satellite imagery, the infrared satellite imagery, is always available. Without this technology, we would not be able to track storm systems at night.
Then there’s the sensor on the satellite that tracks atmospheric moisture, or as we call it in “the biz”, the water vapor imagery (also an infrared sensor). The water vapor sensors aboard weather satellites reveal regions of high atmospheric water vapor concentration between 10,000 and 22,000 feet. It’s a great way to see advancing high clouds from a large scale storm system, and to determine where large moisture plumes are located sometimes known as “atmospheric rivers”.
With all those bases covered, meteorologists can track clouds and storm systems more accurately and with great precision giving you a better forecast.
Space junk and rocket launches have filled our news feeds over the last week or two. One thing is for sure: the GOES satellite series is not junk! It’s here to stay for a while, and will continue to be refined and upgraded through at least 2030. NOAA’s GOES-R Series satellites comprise the Western Hemisphere’s most advanced weather-observing and environmental-monitoring system. It’s continued fine tuning means better forecasts and better monitoring of our changing climate and changing world.
So the next time you see a looping satellite image shown in a weather segment, remember, there’s more to the story than just what meets the eye.