Hyperspectral Sensing Provides Millions of Data Points for Weather Forecasting
L3Harris Corporation’s CrIS instrument improves both the quality and quantity of temperature and moisture data collection, and is one of the top contributors to weather forecast accuracy worldwide.
The accuracy of today’s weather forecasts relies on hyperspectral infrared data collected by instruments on polar-orbiting satellites. Harris is advancing the state of the art in this technology—and significantly improving weather forecasts—through the Cross-track Infrared Sounder.
Predicting the weather is like solving a puzzle with millions of pieces, each representing a data point—a measurement of an element like temperature, moisture, and wind in the atmosphere. The U.S. National Weather Service and other weather services around the world feed these “pieces” into sophisticated computer models to produce weather forecasts that help us prepare for the next hour, the next day, and in some cases, beyond two weeks—forecasts that save lives, protect property, and enhance the economy.
Most weather data comes from satellites, specifically polar satellites that orbit the earth from pole to pole 14 times a day as the earth rotates underneath. In fact, polar satellites are considered the “backbone” of weather forecasts, providing 85 percent of the data that goes into weather models. Through instruments called sounders, these satellites collect the most important data used for weather forecasts today: three-dimensional profiles, or soundings, of temperature and moisture from the earth’s surface to the top of the atmosphere.
Harris’ Cross-track Infrared Sounder (CrIS) is one of these instruments. CrIS is a hyperspectral infrared sounder on board the National Oceanic and Atmospheric Administration’s (NOAA’s) next-generation Joint Polar Satellite System (JPSS) series. Hyperspectral infrared sounders, which use thousands of spectral channels to make detailed measurements of temperature and moisture, improve the accuracy of weather forecasts more than any other type of data, according to the National Academies’ 2017-2027 Decadal Survey for Earth Science and Applications from Space. Representing the state of the art in this type of sensing, CrIS “sees” more than 2,000 channels of infrared light—not visible to the human eye—compared to only 19 channels available from previous technology. The result is millions of new data points captured at more levels of the atmosphere for significantly better weather forecasts.
From Chapter 7 of the 2017-2027 Decadal Survey for Earth Science and Applications from Space. Blue line indicates that hyperspectral infrared sounders such as CrIS improve the accuracy of 24-hour weather forecasts more than any other type of sensor data. (National Academies of Sciences, Engineering, and Medicine; Division on Engineering and Physical Sciences; Space Studies Board)
According to Harris Chief Solutions Engineer Ron Glumb, CrIS data not only feeds into weather models, but also is used directly by National Weather Service forecasters to enable “nowcasting,” or short-term forecasting, of severe weather such as thunderstorms and tornadoes. “CrIS soundings supplement traditional weather balloon observations, offering much denser spatial coverage over both land and ocean,” explains Glumb. “They are also used to detect pockets of cold air aloft that can endanger aircraft and provide cloud height information important to certain users, like warfighters.”
Through CrIS, Harris has not only exceeded the performance of previous infrared sounders, the company also has decreased the instrument’s size and power requirements. “Now we are building on what we achieved with CrIS by continuing to invest in the development of even smaller hyperspectral instruments for weather and other applications, opening the door for use on smallsats and the benefits they offer,” says Glumb.
The first CrIS instrument was launched in 2011 on NOAA’s Suomi National Polar-orbiting Partnership satellite, the first of five satellites in NOAA’s JPSS series. The most recent CrIS was launched in November 2017 on JPSS, now called NOAA-20, with additional CrIS instruments planned for JPSS-2, 3, and 4.
Click here to read Hyperspectral Imaging: An Emerging Tool for Mission Readiness.