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The Atmosphere-Space Interactions Monitor (ASIM) is an Earth observation facility for the study of severe thunderstorms and their role in the Earth’s atmosphere and climate. Upper-atmospheric lightning, known as transient luminous events or terrestrial gamma-ray flashes, occurs well above the altitudes of normal lightning and storm clouds with a process of run-away electron discharge being suggested as the main mechanism. ASIM studies these high-altitude electrical discharges from the external payload platform on the Columbus module of the International Space Station.
The following content was provided by Torsten Neubert, Ph.D., and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Erasmus Experiment Archive.
Torsten Neubert, Ph.D., National Space Institute, Technical University of Denmark (DTU Space), Kongens Lyngby, Denmark
Nikolai Østgaard, Ph.D., Norway
Elisabeth Blanc, Commissariat a l’Energie Atomique, Bruyeres le Chatel, France
Victor Reglero Velascoi, Ph.D., Spain
European Space Agency (ESA), Noordwijk, Netherlands
Sponsoring Space Agency
European Space Agency (ESA)
European Space Agency
ISS Expedition Duration
February 2018 – August 2018
Upper-atmospheric lightning, or transient luminous events, occur well above the altitudes of normal lightning and storm clouds. The most common ground-based observations are of “sprites”, a manifestation of electrical break-down in the mesosphere. Other classes of this phenomenon include the “blue jet” (a discharge propagating upwards into the stratosphere from cloud tops) and ELVES, (a concentric ring of emissions from neutrals excited by a lightning electromagnetic pulse at the bottom edge of ionosphere). Observations have further documented giant discharges that create an electrical breakdown of the atmosphere from the top of thunderstorms, to the bottom ionosphere. Terrestrial gamma-ray flashes are another type of flash phenomenon occurring in the atmosphere above thunderstorms. Evidence suggests that the run-away electron discharge process is the main mechanism in lightning, sprites, and terrestrial gamma-ray flashes.
The Atmosphere-Space Interactions Monitor (ASIM) monitors such phenomena from the external payload platform of ESA’s Columbus Laboratory of the International Space Station. ASIM provides the most comprehensive global survey of transient luminous events and terrestrial gamma-ray flashes in the region of the atmosphere within and above severe thunderstorms, to help determine their physics, and how they relate to lightning. ASIM also quantifies the effects of gravity waves on the mesosphere, studies high-altitude cloud formation, and determines the characteristic of thunderstorms that make them effective in the perturbation of the high-altitude atmosphere. Any improvements in the knowledge of processes occurring in Earth’s atmosphere can help to improve atmospheric models, and hence predictions related to climatology and meteorology.
ASIM is designed to measure the region of the atmosphere within and above severe thunderstorms:
High-altitude electrical discharges in the stratosphere and mesosphere and intra-cloud lightning in the troposphere.
Creation of high-altitude clouds, more specifically, the thunderstorm-driven processes to be observed, e.g. electrical discharges, include the newly discovered Transient Luminous Events (TLEs), and Terrestrial Gamma-ray Flashes (TGFs). Commanding from the ground is required). The Modular Multispectral Imaging Array (MMIA) operates only at night, the Modular X- and Gamma-Ray Sensor (MXGS) is operating day and night.
ASIM observes the atmospheric events of interest in two different ways:
Event-triggered: This is the standard mode. The detectors are on and measuring continuously. The atmospheric event occurs and is detected, and recognized, by the onboard software. The relevant data is then stored.
Time/location-activated: The observation (start, duration) is planned ahead of time. Once the observation has been performed, the relevant data is stored. The Science Team prepares the plans for time/location-activated observations at least 24 hours before the observation takes place.
The ASIM mission improves knowledge in various areas related to space, including the effect of thunderstorms on the ionosphere and the radiation belts, and determining the distribution of meteors in the Earth’s environment, and quantifies their effect on the atmosphere.
The ASIM mission improves knowledge of the effect of dust storms, pollutants from huge cities, forest fires, and volcanoes on cloud formation and electrification, as well as the intensification of hurricanes and its relation to eye-wall lightning activity. Of course, any improvements in the knowledge of processes occurring in Earth’s atmosphere can help to improve atmospheric models, and hence predictions related to climatology and meteorology.
Operational Requirements and Protocols
There are two ways to perform observations: triggering and monitoring:
In the triggered mode, there is a continuous flow of data, which is continuously erased, unless the observed luminous flux fulfills certain criteria (e.g. intensity, duration). In such cases the other ASIM instruments are triggered, the data are saved, and transmitted to ground.
With monitoring, a certain type of observation is planned in advance, for a given duration.