Comparison of High‐Speed Optical Observations of a Lightning Flash From Space and the Ground

Abstract

We analyze a nighttime negative cloud-to-ground lightning flash in Colombia observed from the ground with a high-speed camera at 5,000 images per second and from space by the Atmosphere-Space Interactions Monitor (ASIM) on the International Space Station (ISS), the Lightning Imaging Sensor also on the ISS (ISS-LIS), and the Geostationary Lightning Mapper (GLM) on GOES-16. The space instruments measure the oxygen band at 777.4 nm, allowing for direct comparisons of measurements, and the ground-based camera observes in a wide visible band. After conversion to energy emitted at the cloud top, we find a good linear correspondence of the optical energies measured by the three space instruments, except that GLM values were 3 times higher. We attribute this mainly to the difference in viewing angles between spacecraft and the cloud. Over the entirety of the ASIM observed flash, optical pulses were detected by GLM and LIS, only when the energy reported by ASIM was greater than 332 J and 949 J, respectively. Their detection rate corresponds to 14% and 2.5%, respectively, of the flash duration observed by ASIM. The temporal variation of the high-speed camera luminosity matched well the features observed by ASIM around the time of the stroke but reached~3.9 times higher peak intensity during the return stroke, attributed to its broader spectral sensitivity band and a viewing angle advantage. Plain Language Summary This paper describes the detection of the same lightning flash in Colombia by three different optical imaging systems monitoring lightning activity from space, as well as a high-speed camera at the ground. Each space instrument (ASIM imager and photometer, ISS-LIS, and GLM) has different characteristics, from the spacecraft orbit altitude to the detector spatial and temporal resolution. To make meaningful comparisons, we demonstrate how to calculate the optical energy emitted at the cloud top from the original luminosity values as received by each instrument. Then, reported cloud top energy and lightning detection efficiency for parts of the lightning flash duration are compared. The results show that during this flash, GLM detected only 14% of its total luminous activity as recorded by the sensitive ASIM photometer, and those features were reported 3 times more intense, most likely because of the different viewing angle to the storm. GLM detected a wider luminous cloud top area during the cloud-to-ground stroke than ASIM. The spatial resolution of the ASIM imager allows to identify cloud features also seen in GOES-16 meteorological satellite images.

Initiation of lightning flashes simultaneously observed from space and the ground: Narrow bipolar events

“…3d match well with the ASIM red channel signals in Fig. 3c with higher amplitudes as also reported before by van der Velde et al (2020).…”

A Simultaneous Observation of Lightning by ASIM, Colombia‐Lightning Mapping Array, GLM, and ISS‐LIS

“…The spatial resolution of the cameras is ∼400 m per pixel toward nadir. A more detailed description of the instruments is found in Chanrion et al (2019) and in van der Velde et al (2020).…”

“…Because ASIM instruments provide high temporal and spatial resolution of optical activity in the clouds with additional spectral bands. ASIM offers an opportunity to explore in more detail the performance of the lightning imagers in geostationary orbit (e.g., van der Velde et al, 2020). The comparison of data from ASIM in the low-Earth-orbit of the ISS (∼400 km, 51.6° inclination) to the geostationary instruments is facilitated by a LIS instrument, also on the ISS (Blakeslee et al, 2020).…”

A simultaneous observation of lightning by ASIM, Colombia-Lightning Mapping Array, GLM and ISS-LIS

“…ASIM offers an opportunity to explore in more detail the performance of the lightning imagers in geostationary orbit (e.g. van der Velde et al, 2020). The comparison of data from ASIM in the low-Earth-orbit of the ISS (~400 km, 51.6 o inclination) to the geostationary instruments is facilitated by a LIS instrument, also on the ISS (Blakeslee et al, 2020).…”

“…The spatial resolution of the cameras is ∼ 400 m per pixel towards nadir. A more detailed description of the instruments is found in Chanrion et al (2019) and in van der Velde et al (2020).…”