In just a few years, the National Oceanic and Atmospheric Administration (NOAA) will launch its Geostationary Extended Observations (GeoXO) satellite system. I recently had the pleasure of speaking to one of the scientists working on GeoXO, Dr. Gregory Frost, about what the technology is and how it has the capability to save lives.
First, what is a geostationary satellite and how does it differ from other kinds of satellites? One common type of satellite is a “low-Earth” orbit satellite. These can measure the entire globe within a few days. Geostationary satellites orbit at a much higher altitude (36,000 km compared to 700 km for “low-Earth” satellites) and move at the same rate as the Earth. What this means is, as Dr. Frost says, “A geostationary satellite's instruments are able to continuously view the same part of the Earth at all times. Geostationary satellites generally produce information about a given location on the Earth and the atmosphere above that location on an hourly or even more frequent (minute-by-minute) basis.” This essentially means that geostationary satellites can remain over one location, like the United States and provide near constant updates about important metrics, something other satellites, like ones in “low-Earth” orbit, are unable to do.
One such metric is Atmospheric Composition (AC). AC is basically the amount of atmospheric trace gases (which are all the different gas compounds other than nitrogen, oxygen, argon, and water vapor in the air), how high they are in the atmosphere, and where they are geographically. Atmospheric trace gases only make up 0.1% of the atmosphere, but they still play an important part in our environment. As Dr. Frost points out, “While the total mass of all atmospheric trace gases and aerosols is small, these atmospheric components play pivotal roles in air quality, weather, and climate, both directly and via complex feedbacks with the ocean, the land, and the cryosphere (i.e., ice and snow on the surface).” Though the amount of atmospheric trace gases is small, they interact with our environment in ways that greatly affect our planet and lives, making atmospheric composition an important metric that needs to be measured.
The way AC is measured is through atmospheric composition products (a very creative name) which show where certain trace gases are and how much is present at that point. The way these measurements are taken is through geostationary satellites such as those in the GeoXO mission. The science behind measuring AC is an interesting, yet somewhat complex topic that Dr. Frost explains, “Satellite instruments, like those of … GeoXO and other missions, generally detect sunlight that has either interacted with the Earth's atmosphere and is reflected up to the satellite, or sunlight that has been absorbed and then re-emitted by the Earth.” After the satellite detects sunlight that has interacted with the atmosphere, scientists can measure how intense certain light wavelengths are. This intensity along with the structure of the atmosphere and how it interacts with light will then reflect the amount of trace gas that is in the atmosphere.
Now why does this all matter? Who cares if a satellite can measure how much of a certain gas is in the atmosphere? How does it save lives? Atmospheric compositions products inside geostationary satellites will “produce a lot of data that complements the other observing systems, allowing us to track changes in air pollutants that affect quality, observe atmospheric components that can influence the weather, and monitor greenhouse gases that are the source of climate change.” Not only will they provide more data, but the data will also be much more frequent due to the essential qualities of geostationary satellites: they can monitor one place continuously. Essentially, GeoXO is a step forward in monitoring air quality; tracking dangerous, live-threatening events like wildfires and volcanos; and better measuring environmental regulations and their effect on the climate. With GeoXO, “Federal, state, and local agencies [can] issue better weather and air quality forecasts that help to warn people of severe weather or hazardous air quality, so that they can take actions to avoid these events,” something which will directly save lives of people around the country.