Scientists use instruments on the International Space Station to study phenomena in Earth’s ionosphere or upper atmosphere including thunderstorms, lightning, and transient luminous events (TLEs). TLEs take many forms, including blue jets, discharges that grow upward into the stratosphere from cloud tops, and colorful bursts of energy above storms called Stratospheric/Mesospheric Perturbations Resulting from Intense Thunderstorm Electrification or SPRITES.
TLEs can disrupt communication systems on the ground and pose a threat to aircraft and spacecraft. Understanding these phenomena also could improve atmospheric models and weather predictions. Because these events occur well above the altitudes of normal lightning and storm clouds, they are difficult to observe from the ground. ASIM, an investigation from ESA (European Space Agency), uses a monitor on the exterior of the space station to collect data on TLEs. These data are providing insights into how thunderstorms affect Earth’s atmosphere and helping to improve atmospheric models used for weather and climate predictions.
A study based on ASIM data confirmed that lightning-like discharges at the tops of thunderstorms can create another type of TLE, massive glowing rings in the upper atmosphere known as Emissions of Light and VLF Perturbations from EMP events, or ELVES. This experiment showed that these discharges influence the ionosphere and helped scientists learn more about Earth and space weather.
ASIM-based research also described the physical properties of different types of corona discharges in thunderstorm clouds. Corona discharges are linked to powerful but short-lived electrical bursts near the tops of clouds. The data provide a reference to support further investigation into the mechanisms behind these discharges and their role in the initiation of lightning, an important problem in lightning physics.
Other researchers used ASIM measurements along with ground-based electric field measurements to determine the height of a blue discharge from a thundercloud.
Another ESA investigation, Thor-Davis, evaluated use of a special camera to photograph high-altitude thunderstorms through the windows of the space station’s cupola. The camera can observe thunderstorm electrical activity at up to 100,000 frames per second and could be a useful tool for space-based observation of severe electrical storms and other applications.
The JAXA (Japan Aerospace Exploration Agency) investigation Light-1 CubeSat used detectors integrated into a compact satellite to observe terrestrial gamma-ray flashes in the upper atmosphere. These high intensity, energetic events can expose aircraft, aircraft electronics, and passengers to excessive radiation. Researchers are planning to compare data collected from the mission with ground-based observations to provide more comprehensive maps of lightning and thunderstorms in the atmosphere. Small satellite detectors could cost less and be manufactured in less time than other approaches.
