On November 19, 2016, the GOES-R, a revolutionary new weather weather satellite, was successfully launched from Cape Canaveral. After the satellite was in orbit, it was renamed the GOES-16, keeping with the convention of naming the operational geostationary weather satellites in the order they were launched. The GOES-R/GOES-16 is the first of the next series of four geostationary satellites (GOES-R, S, T, and U). These satellites will replace the current GOES (Geostationary Operational Satellite System) satellites (GOES 13, 14, and 15) and offer a bunch of exciting new capabilities.
Geostationary satellites like the GOES-16 are so called because they continuously hover over a single point above the Earth’s surface. In other words, they take the exact same amount of time to orbit the earth as the Earth takes to complete one full rotation about its axis. To be in this geosynchronous orbit, a satellite must be positioned exactly 22,236 miles directly above the equator. Because they hover over one point, geostationary satellites are extremely useful for monitoring weather data in real-time. With 5 total meteorological geostationary satellites currently deployed by the US (GOES East and West), Europe (Meteosat), India (INSAT), and Japan (GMS), we have nearly continuous satellite coverage of every area on Earth except the polar regions, which are covered by polar-orbiting satellites like the NASA AQUA and TERRA satellites.
The GOES-16 will replace the current GOES East (GOES-13) satellite and will offer coverage of Eastern North America, all of South America, and much of the Northern Atlantic/Southern Pacific. The planned launch date for GOES-S, which will replace GOES West (GOES-15), is March 1, 2018
In addition to simply being a new replacement for GOES-13, the GOES-16 has some awesome new instruments aboard it. There are six new instruments/suites, two dedicated for weather and four dedicated for astronomy/space weather. Let’s learn a little bit about them!
1.) The Advanced Baseline Imager (ABI)
The Advanced Baseline Imager (ABI) is the new imager for the GOES-16 and replaces the old imager on the GOES 13, 14, and 15 satellites. The ABI is significantly more sophisticated than it’s predecessor in three main ways: spectral bands, resolution, and frequency of images.
The ABI will view the Earth in 16 different “spectral bands,” where each spectral band is a specific portion of the electromagnetic spectrum. The old GOES imager only viewed the Earth in 5 different spectral bands: one visible band and four infrared bands. Table and diagram below are taken from a document about the GOES satellite from the UW-Madison Space Science and Engineering Center (SSEC).
Below is a list of the spectral bands the ABI will use. With more spectral bands come more capabilities. One of the capabilities I am most excited about is that our visible images will now be in color instead of black and white. I absolutely love the beautiful visible imagery from the MODIS sensor aboard NASA’s AQUA and TERRA satellites, and it will be wonderful to have similar imagery from a geostationary satellite.
The resolution (pixel size) of our current imager is 1 km for the one visible band and 4 km for the four infrared bands. The GOES R will halve these numbers, and because pixels are squares, this means the GOES-16 will have four times the resolution. The ABI is actually already installed aboard Japan’s GMS satellite, and it offers some spectacular shots. Here’s an image of Australia shot last Saturday (Friday evening for us in the Pacific Northwest). What a beautiful shot!
Finally, the ABI will be able to scan the atmosphere much more quickly than the current imager, therefore giving us faster image intervals. The current imager aboard the GOES gives us satellite pictures every 15 minutes, but the ABI will give us those images every 5 minutes. Additionally, it has the capability of zooming in on a small area and taking shots of it every 30 seconds. I’m looking forward to these shots for tracking the evolution of severe thunderstorms over the Great Plains!
2.) The Geostationary Lightning Mapper
One of the weather instruments aboard the GOES-16 that I and many other meteorologists are extremely excited about is the Geostationary Lightning Mapper (GLM). The GLM will monitor lightning flashes by detecting sudden optical changes from space. It is the first operational lightning mapper to be flown in geostationary orbit.
We are able to monitor lightning over the U.S. and just off our coast by using ground-based sensors that measure pulses of electromagnetic radiation from lightning strikes. Unfortunately, these systems mainly capture cloud-to-ground flashes and not cloud-to-cloud, which are more common. Moreover, they don’t capture lightning that occurs extremely far away. With the GLM, not a single flash will be missed.
Lightning data is good for more than, well, just knowing if there is lightning. According to University of Washington Professor Cliff Mass, lightning tells us that (a) the atmosphere is saturated, (b) the atmosphere is unstable (large decrease in temperature with height, making it easier for warm air at the surface to rise), and (c) there is ice in the cloud from which the lightning strike originated, as ice particles colliding into each other are responsible for separating charges in a cloud and creating lightning. This information can then be fed into models to give us a more complete description of the atmosphere and better forecasts.
The ABI and GLM are the main instruments aboard the GOES-R for analyzing the weather on Earth. But there four more components aboard the GOES-R that monitor the environment around the satellite, the Earth’s magnetosphere, and the sun, and they deserve recognition too!
Astronomy/Space Weather Instruments
1.) The Space Environment In-Situ Suite
The Space Environment In-Situ Suite (SEISS) is a suite of four sensors that will track electron, proton, and ion fluxes in the magnetosphere.
The MPS-LO (Magnetospheric Particle Sensor-LO) measures the flux of low-energy electrons & protons in space and will let scientists know how the GOES-R is accumulating charge over time. If the spacecraft accumulates charge, an electrostatic discharge (ESD) can occur as the spacecraft attempts to release excess charge. Lightning is an example of a powerful ESD we are all familiar with, but very small ESDs can still cause massive damage to these very expensive instruments aboard satellites.
The MPS-HI sensor is like the MPS-LO sensor but, as the name suggests, measures the flux of medium-to-high energy electrons & protons. High electron fluxes in particular are very damaging to spacecraft due to the potential for an ESD inside the spacecraft.
The SGPS (Solar and Galactic Proton Sensor) will measure protons inside the Earth’s magnetosphere originating from the sun or other energy sources throughout the Universe. This information will be used by the Space Weather Prediction Center to issue Radiation Storm Warnings to protect both astronauts and those in high-altitude aircraft from radiation. Additionally, radiation storms can cause communication blackouts, so the SGPS will provide some lead time for those as well.
The EHIS (Energetic Heavy Ion Sensor) will measure the fluxes of “heavy ions” ranging from hydrogen to nickel in the Earth’s magnetosphere. Like the SGPS, the EHIS is useful for warning astronauts and high-altitude aircraft of high levels of radiation in the magnetosphere.
2.) The Extreme Ultraviolet and X-Ray Irradiance Sensors (EXIS)
The Extreme Ultraviolet and X-Ray Irradiance Sensors (EXIS) monitor radiation in the extreme ultraviolet and x-ray wavelengths originating from the sun, thus providing scientists information regarding the power of the solar wind. Monitoring the sun is very important because solar flares and coronal mass ejections can cause massive communication blackouts by damaging satellites, and the EXIS will allow the NOAA Space Weather Prediction Center to issue warnings of radio blackouts that could disrupt communication systems for millions of people on Earth.
3.) The Magnetometer
The magnetometer (MAG) will measure the Earth’s magnetic field. Magnetometers are some of the most widely-used observation instruments aboard satellites today, and each of the current GOES satellites have one. Monitoring the magnetic field is important for both providing warnings to satellite operators/power utilities in the event of a geomagnetic storm and to help model Earth’s magnetosphere for research.
4.) The Solar Ultraviolet Imager
Like the EXIS, the Solar Ultraviolet Imager (SUVI) also monitors radiation from the sun. However, while the EXIS is a suite of sensors that measure radiation, the SUVI is a telescope that provides us with images of the sun in the extreme ultraviolet part of the UV spectrum. Like the EXIS, information from the SUVI will be used by the Space Weather Prediction Center to forecast geomagnetic storms that could affect satellites, communication, and the power grid.
The SUVI replaces the current SXI (Solar X-ray Imager) aboard the GOES satellites and will offer us better resolution and spatial coverage of the sun than its predecessor. And as the picture above shows, the SXI was no slouch in the imagery department.
In conclusion, the GOES-16 is a vast improvement over our previous generation of GOES satellites and will offer invaluable information to meteorologists and astronomers alike. Once GOES-S is launched (and thus is named GOES-17), our coverage will expand to Western North America and much of the Pacific.
Written by Charlie Phillips – charlie.weathertogether.net. Last updated 12/1/2017