Observations from NASA’s newest storm-observing satellites have captured the evolution of Hurricane Adrian’s structure as the storm strengthens.

In the last week of June 2023, the first hurricane of this season passed off Mexico in the eastern part of the Pacific Ocean. The storm, Hurricane Adrian, was moving northwest of the coast and posed no threat to landfall. However, Hadrian attracted attention for another reason, especially among academics. It was the first hurricane observed by NASA’s newest storm-tracking satellites.

This animation shows the evolution of the clouds of Hurricane Adrian from the morning of June 28 to the afternoon of June 29. Nearby, Beatrice was turning into a tropical storm, seen in these images as less organized clouds closer to the beach. Credit: NASA

Data from the animation (top) and sequence (bottom) images were acquired by the Time-Based Precipitation Structure Observations and the TROPICS mission, which stands for Smallsats Constellation and Storm Intensity. The images shown were selected from about two dozen images taken by satellites at the time.

“As communities around the world experience the increasing effects of increased extreme weather, it has never been more important to deliver timely data to those who need it most to protect livelihoods and lives,” said NASA Administrator Bill Nelson. “TROPICS will provide critical information for forecasters, helping us better prepare for hurricanes and tropical storms.”

TROPICS is a constellation of four identical CubeSats designed to monitor tropical cyclones. Economical satellites the size of a milk carton were launched by Rocket Lab in May 2023. Each TROPICS CubeSat includes a microwave radiometer that collects data through 12 channels to detect temperature, humidity and precipitation during and around the storm.

The image in this animation was created from data collected by a single channel (205 GHz) susceptible to cloud ice. Each scene shows the brightness temperature; that is, the radiation intensity that can be detected at that frequency of the channel moving upwards from the cloud layers to the satellites.

Cool glowing temperatures (blue and white) represent radiation scattered by ice particles in storm clouds. The lower the temperature, the more ice there can be in the atmosphere column. Cloud ice is a sign of intense heat and moisture movement (convection) during a storm, said Will McCarthy, TROPICS program scientist and director of the Weather and Atmospheric Dynamics Program at NASA Headquarters.

Scott Brown, a research meteorologist at NASA’s Goddard Space Flight Center and a TROPICS project scientist, explained that the patterns seen in the brightness temperature data can show the location of rain bands, the convection intensity, whether a storm forms an eye and how these structures change over time. All of this is important for understanding how storms will develop.

“Structural changes in luminosity temperature can help us determine whether a storm is intensifying,” said Patrick Durand, assistant program manager for mission programs at NASA’s Marshall Space Flight Center. These structural changes are less noticeable in natural color images, which mostly show cloud tops. And some features, such as the eye, often appear in microwave images before being detected by infrared sensors on other satellites.

Some of these structural changes can be seen in animation and a series of images. The first frame of the animation shows the development of the storm on June 28, which can be seen as a warmer area surrounded by cooler areas associated with clouds and falling ice. At the time this image was created, NOAA’s National Hurricane Center had recently upgraded Adrian from a tropical storm to a Category 1 hurricane. This image continued to strengthen throughout the series and remained a Category 1 storm.

In the image taken at 10:58 p.m. ET (4:58 p.m. local time) on June 29, the eyewall shows stronger convection and the eye appears smaller, usually during storm intensification. By 22:18 UTC (4:18 p.m. local time) on that day, strong convection could be seen in the south of the eye, a new rain band developed on the north side and the eye was reduced to its smallest size seen in the image series.

Similar microwave measurements can be made by other satellites, such as the Global Precipitation Measurement (GPM) mission. But TROPICS has a time advantage. The orbits of most science satellites only allow us to observe storms every 6 to 12 hours, while Earth orbit and multiple TROPICS satellites allow us to catch storms approximately every hour. This is a huge advantage when trying to understand a fast moving storm.

“Long-term repeat visit observations of tropical cyclones reveal the detailed structure of tropical cyclones’ inner eye and rainbands,” said William Blackwell, the mission’s principal investigator at the MIT Lincoln Laboratory. “The rapidly updated data provided by TROPICS clearly demonstrate the dynamic evolution of storm structure and environmental conditions.”

As TROPICS continues to collect data on tropical cyclones, weather researchers will learn more about environmental factors that affect storm structure and intensity. Such information can be useful to NOAA, the US Joint Typhoon Warning Center and international organizations responsible for hurricane, typhoon and cyclone forecasting. Source