Scattering of lightning optical radiation by complex, inhomogeneous clouds

Author(s):  
Alejandro Luque Estepa ◽  
Francisco José Gordillo-Vázquez ◽  
Dongshuai Li ◽  
Alejandro Malagón-Romero ◽  
Sergio Soler ◽  
...  

<p>Lightning flashes emit intense optical radiation that can be detected from space. Several space missions work by observing this light in order to investigate lightning, thunderstorms, and other phenomena closely associated to them such as Transient Luminous Events (TLEs) and Terrestrial Gamma-ray Flashes (TGFs).</p><p>In its path towards a satellite-borne observing device, the optical radiation emitted by a flash is scattered many times by the droplets and ice crystals in the cloud. The detected signal is thus shaped by and contains information about the cloud geometry and composition. This is particularly relevant for instruments with a high spatial resolution such as the cameras in the Modular Multispectral Imaging Array (MMIA), which is part of the Atmosphere-Space Interactions Monitor (ASIM) currently onboard the International Space Station. These cameras provide images of lightning-illuminated cloud tops with a resolution of about 400 m.</p><p>We present a numerical code that can simulate light scattering in clouds with complex geometries and location-dependent droplet density and effective radius. The cloud geometry is specified by a number of elementary shapes (e.g. spheres and cylinders) that can be linearly deformed as well as combined by set operations such as unions, intersections and subtractions. The cloud composition can be specified by arbitrary functions. Designed to aid in the interpretation of satellite images, the code simulates spatially resolved observations from an arbitrary viewpoint. Some examples and applications of this tool will be discussed.</p>

2020 ◽  
Author(s):  
Matteo Battisti ◽  
Enrico Arnone ◽  
Mario Bertaina ◽  
Marco Casolino ◽  
Olivier Chanrion ◽  
...  

<p>The search for the physical mechanisms of lightning, transient luminous events and terrestrial gamma-ray flashes is receiving an extraordinary support by new space observations that have recently become available. Next to lightning detectors on geostationary satellites, new low orbit experiments are giving an unprecedented insight in the very source of these processes. Looking at the physics behind these new observations requires however to have a variety of different instruments covering the same event, and this is proving extremely challenging. Here, we present observations of UV emissions of elves and lightning taken for the first time simultaneously from the two instruments Mini-EUSO and ASIM operating on the international space station. Mini-EUSO was designed to perform observations of the UV-light night emission from Earth. It is a wide field of view telescope (44°x44° square FOV) installed for the first time on October 2019 inside the Zvezda Module of the ISS, looking nadir through a UV transparent window. Its optical system consists of two Fresnel lenses for light collection. The light is focused onto an array of 36 multi-anode photomultiplier tubes (MAPMT), for a total of 2304 pixels. Each pixel has a footprint on ground of ~5.5 km. The instrument is capable of single-photon counting on three different timescales: a 2.5 microsecond (D1) and a 320 microsecond (D2) timescale with a dedicated trigger system, and a 40.96ms timescale (D3) used to produce a continuous monitoring of the UV emission from the Earth. ASIM is an experiment dedicated to lightning and atmospheric processes. Its Modular Multispectral Imaging Array (MMIA) is made of an array of 3 high speed photometers probing different wavelength sampling at rates up to 100 kHz, and 2 Electron Multiplication Charge Coupled Devices (EM-CCDs) with a sub-km spatial resolution with an 80° FOV and recording up to 12 frames per second. Mini-EUSO detected several bright atmospheric events like lightning and elves, with a few km spatial resolution and different time resolutions, probing therefore different stages of the electromagnetic phenomena. Observations from Mini-EUSO were simultaneously captured by ASIM instruments, allowing for the first time to compare and complement the capabilities of the two instruments with a time inter-calibration based on unambiguous series of lightning detections.</p>


2020 ◽  
Author(s):  
Jesús Alberto López ◽  
Joan Montanyà ◽  
Oscar van der Velde ◽  
Ferran Fabró ◽  
Javier Navarro ◽  
...  

<p>Since April 2018, the Atmosphere-Space Interactions Monitor (ASIM) has been in operation on board the International Space Station (ISS). ASIM is composed of the Modular X-and Gamma Ray Sensor (MXGS) as well as a multispectral and high resolution array of photometers and cameras, called the Modular Multispectral Imaging Array (MMIA). These instruments allow us to investigate Terrestrial Gamma-Flashes, Transient Luminous Events and their interactions with thunderstorms and lightning flashes.</p><p>The Colombia Lightning Mapping Array (COL-LMA), operational since 2017, is the first VHF range network installed and working in a tropical region, and can contribute to the electrical understanding of thunderstorms and lightning leader processes associated with high energy phenomena in the upper atmosphere.</p><p>This work employs data from the MMIA array to investigate optical emission patterns at different bands (337 nm, 180-230 nm and 777.4 nm) caused by lightning leader development and cloud-to-ground flashes, derived from the COL-LMA and LINET network respectively. All cases are also correlated with optical observation from the Lightning Imaging Sensor (LIS) on board the ISS, and the Geostationary Lightning Mapper sensor on the GOES-R satellite.</p><p>The region of study is defined by the high detection-efficiency area of the COL-LMA around the Magdalena river valley. MMIA-ASIM information since July 2019 corresponding to passes over this tropical region has been analysed.</p>


2020 ◽  
Author(s):  
Andrey Mezentsev ◽  
Nikolai Østgaard ◽  
Martino Marisaldi ◽  
Pavlo Kochkin ◽  
Torsten Neubert ◽  
...  

<p>Launched and installed at the International Space Station in April 2018, the Atmosphere-Space Interactions Monitor (ASIM) provides science data since June 2018. Suite of onboard instruments contains optical and high energy detectors payloads. Modular Multi-spectral Imaging Array (MMIA) includes three photometers (180-240 nm, 337 nm and 777.4 nm) sampling at 100 kHz, and two cameras (337 nm and 777.4 nm) sampling at 12 Hz. It allows for lightning and transient luminous events (TLEs) observations during the orbital eclipses. The Modular X- and Gamma-ray Sensor (MXGS) detects X- and Gamma-ray photons, and is dedicated to detection of Terrestrial Gamma-ray Flashes (TGFs). The mutual relative timing accuracy between MXGS and MMIA is as good as +/- 5 µs.</p><p> </p><p>TGFs are known to be associated with the +IC lightning discharges. ASIM provides a unique possibility for simultaneous observations of TGFs together with the underlying optical activity inside the thundercloud. In this contribution we summarize the almost two years of ASIM observations to make an overview of the various optical contexts accompanying the TGF production.</p>


2020 ◽  
Vol 13 (11) ◽  
pp. 5549-5566
Author(s):  
Alejandro Luque ◽  
Francisco José Gordillo-Vázquez ◽  
Dongshuai Li ◽  
Alejandro Malagón-Romero ◽  
Francisco Javier Pérez-Invernón ◽  
...  

Abstract. We describe a computer code that simulates how a satellite observes optical radiation emitted by a lightning flash after it is scattered within an intervening cloud. Our code, CloudScat.jl, is flexible, fully open source and specifically tailored to modern instruments such as the Modular Multispectral Imaging Array (MMIA) component of the Atmosphere–Space Interactions Monitor (ASIM) that operates from the International Space Station. In this article, we describe the algorithms implemented in the code and discuss several applications and examples, with an emphasis on the interpretation of MMIA data.


2020 ◽  
Author(s):  
Olivier Chanrion ◽  
Torsten Neubert ◽  
Chiara Zuccoti ◽  
Matthias Heumesser ◽  
Krystallia Dimitriadou ◽  
...  

<p>The Atmosphere-Space Interaction (ASIM) mission was launched on April 2, 2018 and installed on an external platform of the Columbus Module of the International Space Station the 13th.</p><p>The main objectives of the mission are to observe and study thunderstorms and their interaction with the atmosphere. ASIM embarks two main instruments pointing at Nadir, the Modular Multispectral Imaging Array (MMIA) observing in the visible and the Modular X- and Gamma- ray Sensor (MXGS) observing in the X- and Gamma-ray bands.</p><p>In this presentation we focus on observations made by the MMIA which includes two cameras operating in the bands 337/5 nm and 777.4/3 nm and three photometers operating in the bands 180-230 nm, 337/5 nm and 777.4/5 nm. Specifically, we analyze the short duration pulses recorded in the 180-230 nm band.</p><p>After about 2 years of operations, more than 2500 of such events were identified in the data. They are likely to be recordings of ELVEs (Emissions of Light and Very low frequency perturbation due to Electromagnetic pulse sources), occurring in the ionosphere in response to lightning currents.</p><p>We show the amplitude, spatial and temporal distributions of the events and compare the results with those of previous studies. We present an analysis of the temporal characteristics of the pulses themselves and of their delays regarding the parent lightning observed in the other ASIM photometers or in the GLD360 ground lightning detection network recordings. Finally, we compare some typical events with modeling.</p>


2020 ◽  
Author(s):  
Ingrid Bjørge-Engeland ◽  
Nikolai Østgaard ◽  
Chris Alexander Skeie ◽  
Andrey Mezentsev ◽  
Torsten Neubert ◽  
...  

<p>In 2018, the Atmospheric Space Interactions Monitor (ASIM) was launched and mounted onboard the Columbus module of the International Space Station (ISS). Using data from the Modular X- and Gamma-Ray Sensor (MXGS) and the Modular Multispectral Imaging Array (MMIA), we investigate the time sequence of the TGFs detected by MXGS and the optical pulses detected by the MMIA. The optical pulses are observed in the 337 nm and 777.4 nm, and the X- and gamma-rays are detected by the High Energy Detector of MXGS, which is sensitive to energies from 300 keV to more than 30 MeV. We will also look into the TGF duration and any correlation with the time between the TGFs and the main optical signals. The data used is from June 2018 (shortly after mounting on the Columbus module) until the end of March 2019, when the relative timing uncertainty between the two instruments was +/- 80 us. The data after this is presented in Skeie et al.</p>


2021 ◽  
Author(s):  
Ingrid Bjørge-Engeland ◽  
Nikolai Østgaard ◽  
Andrey Mezentsev ◽  
Torsten Neubert ◽  
Chris Alexander Skeie ◽  
...  

<p><span>The Atmospheric Space Interactions Monitor (ASIM) was launched in 2018, and has since then observed Terrestrial Gamma-ray Flashes (TGFs) and Transient Luminous Events (TLEs). ASIM consists of the Modular X- and Gamma-ray Sensor (MXGS) and the Modular Multispectral Imaging Array (MMIA). Using data from both MXGS and MMIA, we investigate observations of TGFs (detected by MXGS) with accompanying elves (detected by MMIA). We study the optical signatures of the elves detected by a photometer of MMIA operating in the 180-230 nm band. Lightning sferics associated with these events have been detected by WWLLN and GLD360. Several TGFs have associated lightning sferics outside the field of view of MMIA, but due to the expanding rings of the elves we can still observe optical signatures from accompanying elves. Using GLD360 data we also study properties of the lightning strokes. </span></p>


2020 ◽  
Author(s):  
Martino Marisaldi ◽  
Andrey Mezentsev ◽  
David Sarria ◽  
Anders Lindanger ◽  
Nikolai Østgaard ◽  
...  

<p>The Atmosphere Space Interaction Monitor (ASIM) mission onboard the International Space Station is the first mission specifically dedicated to the observation of Terrestrial Gamma-ray Flashes (TGF) and Transient Luminous Events (TLE). ASIM, together with the Fermi and AGILE satellites, are the only three currently operating missions capable to detect TGFs from space. Depending on orbital parameters, pairs of these missions periodically get closer than few hundreds kilometers, observing the same region on the Earth surface for up to several tens of seconds. This offers the unique chance to observe the same TGF from two different viewing angles. Such observations allow to probe the TGF production geometry and possibly put constraints on production models and electric field geometry at the source.</p><p>Here we present four TGFs detected by ASIM and simultaneously detected by Fermi (three events) or AGILE (one event) in the period June 2018 - November 2019. We present location data, light curves, and possible constraints to emission geometry based on coupled observations and Monte Carlo simulations. </p>


2020 ◽  
Author(s):  
Alejandro Luque ◽  
Francisco José Gordillo-Vázquez ◽  
Dongshuai Li ◽  
Alejandro Malagón-Romero ◽  
Francisco Javier Pérez-Invernón ◽  
...  

Abstract. We describe a computer code that simulates how a satellite observes optical radiation emitted by a lightning flash after it is scattered within an intervening cloud. Our code, CloudScat.jl, is flexible, fully open source and specifically tailored to modern instruments such as the Modular Multispectral Imaging Array (MMIA) component of the Atmosphere-Space Interactions Monitor (ASIM) that operates from the International Space Station. In this article we describe the algorithms implemented in the code and discuss several applications and examples, with an emphasis on the interpretation of MMIA data.


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