Time Evolution of Satellite‐Based Optical Properties in Lightning Flashes, and its Impact on GLM Flash Detection

Zhang, Daile; Cummins, K. L.

doi:10.1029/2019jd032024

Cited by 52 publications

(103 citation statements)

References 30 publications

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“…Here we used the local pixel footprint area ( a ) which in the corner of the field of view of the instruments on the ISS is significantly larger than in nadir direction. For a detailed explanation about the conversion, refer to Zhang and Cummins (2020, Appendix A). For conversion of the photometer flux density values (W m −2 ), we multiplied by sample time, yielding q /(π D 2 /4), then used their formula A.7 (left side) where it can be noted that pixel footprint area a divided by pixel solid angle ω yields distance squared ( z 2 ), eliminating the need to know the emitting area.…”

Section: Methods and Datamentioning

confidence: 99%

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

Velde

Montanyà

Neubert

et al. 2020

Earth and Space Science

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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.

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Section: Methods and Datamentioning

confidence: 99%

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

Velde

Montanyà

Neubert

et al. 2020

Earth and Space Science

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“…Analyses of optical and combined optical/RF emissions from lightning have provided a wealth of insights on processes involved in the lightning discharge (Bitzer, 2017; Noble et al, 2004; Østgaard et al, 2013; Peterson et al, 2017; Peterson & Rudlosky, 2019; Suszcynsky et al, 2000; Thomas et al, 2000; Ushio et al, 2002; Zhang & Cummins, 2020). Hence, the capability of ISS LIS to detect the optical fingerprint of lightning on a global scale with a relatively high DE makes for a unique data set to compare with optical, RF, and other measurements of lightning and related atmospheric electrical phenomena.…”

Section: Current and Future Cross‐platform Sciencementioning

confidence: 99%

“…Just a single flash observation provides confirmation of a convective system to the AWC, enabling aircraft to be rerouted safely around these systems. Due to reduced DE during the day, as well as coarser pixel resolution off boresight, weaker and smaller size flashes are not as well detected by the GLM instruments (Zhang & Cummins, 2020). For these reasons AWC and other NWS service centers have found that ISS LIS augments their confidence in GLM (and ground‐based) detection of lightning especially over oceanic regions (Goodman, Blakeslee, Pettegrew, Terborg, Stevenson, et al, 2020).…”

Section: Analysis and Findingsmentioning

confidence: 99%

Three Years of the Lightning Imaging Sensor Onboard the International Space Station: Expanded Global Coverage and Enhanced Applications

et al. 2020

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The Lightning Imaging Sensor (LIS) was launched to the International Space Station (ISS) in February 2017, detecting optical signatures of lightning with storm‐scale horizontal resolution during both day and night. ISS LIS data are available beginning 1 March 2017. Millisecond timing allows detailed intercalibration and validation with other spaceborne and ground‐based lightning sensors. Initial comparisons with those other sensors suggest flash detection efficiency around 60% (diurnal variability of 51–75%), false alarm rate under 5%, timing accuracy better than 2 ms, and horizontal location accuracy around 3 km. The spatially uniform flash detection capability of ISS LIS from low‐Earth orbit allows assessment of spatially varying flash detection efficiency for other sensors and networks, particularly the Geostationary Lightning Mappers. ISS LIS provides research data suitable for investigations of lightning physics, climatology, thunderstorm processes, and atmospheric composition, as well as real‐time lightning data for operational forecasting and aviation weather interests. ISS LIS enables enrichment and extension of the long‐term global climatology of lightning from space and is the only recent platform that extends the global record to higher latitudes (±55°). The global spatial distribution of lightning from ISS LIS is broadly similar to previous data sets, with globally averaged seasonal/annual flash rates about 5–10% lower. This difference is likely due to reduced flash detection efficiency that will be mitigated in future ISS LIS data processing, as well as the shorter ISS LIS period of record. The expected land/ocean contrast in the diurnal variability of global lightning is also observed.

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“…It is worth noting that the number of return strokes per flash was not the only factor that explains the flash duration. Changes in the electric field and current intensity will also affect the flash duration [86,124]. Figure 8 shows a comparison of the statistical results for the characteristic parameters of radiation in the LMI and LIS flashes.…”

Section: Optical Radiation Characteristics Of Lightning Signalsmentioning

confidence: 99%

Preliminary Observations from the China Fengyun-4A Lightning Mapping Imager and Its Optical Radiation Characteristics

et al. 2020

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The Fengyun-4A (FY-4A) Lightning Mapping Imager (LMI) is the first satellite-borne lightning imager developed in China, which can detect lightning over China and its neighboring regions based on a geostationary satellite platform. In this study, the spatial distribution and temporal variation characteristics of lightning activity over China and its neighboring regions were analyzed in detail based on 2018 LMI observations. The observation characteristics of the LMI were revealed through a comparison with the Tropical Rainfall Measuring Mission (TRMM)-Lightning Imaging Sensor (LIS) and World Wide Lightning Location Network (WWLLN) observations. Moreover, the optical radiation characteristics of lightning signals detected by the LMI were examined. Factors that may affect LMI detection were discussed by analyzing the differences in optical radiation characteristics between LMI and LIS flashes. The results are as follows. Spatially, the flash density distribution pattern detected by the LMI was similar to those detected by the LIS and WWLLN. High-flash density regions were mainly concentrated over Southeastern China and Northeastern India. Temporally, LMI flashes exhibited notable seasonal and diurnal variation characteristics. The LMI detected a concentrated lightning outbreak over Northeastern India in the premonsoon season and over Southeastern China in the monsoon season, which was consistent with LIS and WWLLN observations. LMI-observed diurnal peak flash rates occurred in the afternoon over most of the regions. There was a “stepwise” decrease in the LMI-observed optical radiance, footprint size, duration, and number of groups per flash, from the ocean to the coastal regions to the inland regions. LMI flashes exhibited higher optical radiance but lasted for shorter durations than LIS flashes. LMI observations are not only related to instrument performance but are also closely linked to onboard and ground data processing. In future, targeted improvements can be made to the data processing algorithm for the LMI to further enhance its detection capability.

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Time Evolution of Satellite‐Based Optical Properties in Lightning Flashes, and its Impact on GLM Flash Detection

Cited by 52 publications

References 30 publications

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

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

Three Years of the Lightning Imaging Sensor Onboard the International Space Station: Expanded Global Coverage and Enhanced Applications

Preliminary Observations from the China Fengyun-4A Lightning Mapping Imager and Its Optical Radiation Characteristics

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