A pair of microwave radiometers gathered data on Hurricane Ian as they passed over the Caribbean Sea aboard the International Space Station (ISS).
Two recently launched instruments captured images of Hurricane Ian on Tuesday, September 27, 2022, as the storm approached Cuba on its way north toward the U.S. mainland. Designed and built at NASA’s Jet Propulsion Laboratory in Southern California, these instruments were created to provide forecasters data on weather over the open ocean.
COWVR (short for Compact Ocean Wind Vector Radiometer) and TEMPEST (Temporal Experiment for Storms and Tropical Systems) observe the planet’s atmosphere and surface from aboard the ISS, which passed in low-Earth orbit over the Caribbean Sea at about 12:30 a.m. EDT.
According to the National Hurricane Center, Ian made landfall in Cuba’s Pinar del Rio province at 4:30 a.m. EDT. At that time, it was a Category 3 hurricane, with estimated wind speeds of 125 mph (205 kph).
The image at the top of the page combines microwave emissions measurements from both COWVR and TEMPEST. White sections indicate the presence of clouds. Green portions indicate rain. Yellow, red, and black indicate where air and water vapor were moving most swiftly. Ian’s center is seen just off of Cuba’s southern coast, and the storm is shown covering the island with rain and wind.
COWVR and TEMPEST sent the data for this image back to Earth in a direct stream via NASA’s tracking and data relay satellite (TDRS) constellation. The data were processed at JPL and made available to forecasters less than two hours after collection.
COWVR, which is comparable in size to a minifridge, measures natural microwave emissions over the ocean. The magnitude of the emissions increases with the amount of rain in the atmosphere, and the strongest rain produces the strongest microwave emissions. About the size of a cereal box, TEMPEST tracks microwaves at a much shorter wavelength. This allows it to see ice particles within the hurricane’s cloudy regions that are thrust into the upper atmosphere by the storm.
Both microwave radiometers were developed to demonstrate that smaller, more energy-efficient, more simply designed sensors can perform most of the same measurements as current space-based weather instruments that are heavier, consume more power, and cost much more to construct.
COWVR’s development was funded by the U.S. Space Force, and TEMPEST was developed with NASA funding. The U.S. Space Test Program-Houston 8 (STP-H8) is responsible for hosting the instruments on the space station under Space Force funding in partnership with NASA. Data from the instruments is being used by government and university weather forecasters and scientists. The mission will inform the development of future space-based weather sensors, and researchers are working on mission concepts that would take advantage of the low-cost microwave sensor technologies to study long-standing questions, such as how heat from the ocean fuels global weather patterns.