The CubeSpark mission concept is being developed as a constellation of up to six satellites in low-Earth orbit (LEO) for high resolution 3D lightning mapping using optical and radio frequency (RF) sensors. Individual lightning VHF signals are simulated from Earth’s atmosphere through the ionosphere to each satellite, using their arrival times to reconstruct source locations. Here we present recent updates to these simulations based on improved ionospheric modeling, with a focus on the expected three-dimensional resolution. These studies include testing from the equator up to high latitudes, with varying vertical total electron content (vTEC), and using between one and six orbiting stations. In addition to the more robust ionosphere model, the constellation formation has also been updated to reduce its resulting errors and increase the effective range of VHF geolocation from space. The goals of CubeSpark include mapping thundercloud charge structure as well as lightning channel lengths relevant to climatology, meteorology, and more. These applications require location uncertainty less than 1-2 km in each dimension. This improved algorithm shows sufficient resolution up to high latitudes, including significantly larger areas having 3D resolution less than 1 km. Analysis of the distributions of biases in simulated arrival times has also revealed the unexpected relationship between the shape of those distributions and the resulting uncertainties. This work helps to refine our understanding of the sources of error in lightning geolocation and reinforces the potential for post-processing improvements in this and other similar systems.

Lightning↗

NASA NTRSDate not supplied

Evaluation of Present and Future Spaceborne Lightning Observations During the ALOFT Campaign

The ALOFT1 campaign took place during July 2023. The NASA ER-2 high-altitude aircraft was based in Tampa, Florida, and flew approximately 60 hours sampling tropical and sub-tropical thunderstorms that were mostly contained within the common fields of view of GLM4-16 and GLM-18. In addition, multiple underflights of the ISS LIS5 instrument occurred. The FEGS2 and LIP6 instrument suite on the ER-2 provided a combination of multispectral optical, slow and fast electric field change, and three-dimensional electric field measurements of lightning and thunderstorms. Notably, in addition to the 777-nm band used by GLM and LIS, FEGS also observed at 337 nm, 500 nm, 868 nm, wideband visible-to-infrared, and shortwave infrared. A spectrometer that spanned most major lightning bands from the ultraviolet to infrared was included. Observations of gamma-ray production by thunderstorms were also collected during ALOFT. Thus, the lightning-observing suite on the ER-2 during ALOFT provides an unprecedented suborbital dataset for direct optical-to-optical and indirect radio-to-optical validation of existing spaceborne lightning sensors like GLM and LIS. In addition, the multispectral observations from FEGS enables evaluation of current and future spaceborne lightning-observing concepts. For example, the 337-nm channel is relevant to both existing missions like ASIM7 as well as future concepts like the CubeSpark mission currently being formulated by NASA. Complementary to LIS, the ISS also carries the STP-H88 payload, which features microwave radiometers covering 18-182 GHz, while the ER-2 carried radiometers covering 10-684 GHz, enabling evaluation of spaceborne passive microwave measurements that are complementary to the lightning observations. 1. Airborne Lightning Observatory for FEGS2 and TGFs3 2. Fly’s Eye GLM4 Simulator 3. Terrestrial Gamma-ray Flashes 4. Geostationary Lightning Mapper 5. International Space Station Lightning Imaging Sensor 6. Lightning Instrument Package 7. Atmosphere-Space Interactions Monitor 8. 8th Space Test Program – Houston mission

Timothy Lang↗

NASA NTRSDate not supplied

Future Lightning Instruments for Weather and Climate Monitoring From LEO

Lightning is not only a natural hazard, but it also holds information about physical processes at work in deep convection and influences atmospheric oxidants that modulate ozone and methane. Hence, spaceborne lightning observations are essential for monitoring extreme events and feedbacks in Earth’s climate system. Low-Earth orbiting (LEO) lightning mapping instruments established a 25-year record of global lightning activity and resulted in a wealth of studies that motivated its designation as an Essential Climate Variable by the World Meteorological Organization. Although geostationary observations of lightning have become increasingly available since 2017, LEO lightning mappers continue to serve critical needs given their unique vantage point and acceptance as a unifying reference for geostationary lightning mapper and ground-based global lightning datasets. At the close of 2023, the Lightning Imaging Sensor (LIS) will cease operations on the International Space Station, which introduces a critical gap in LEO-based monitoring of global lightning activity. To address this need, NASA is developing new lightning mapping technology that enables future LEO-based satellite missions. Existing LEO-based lightning mappers rely on narrowband optical emissions centered on 777.4-nm and detectors that capture 500 images per second to detect lightning both day and night. Lightning can also produce optical emissions in a narrowband centered on 337-nm without any corresponding emissions at the traditionally used near-infrared (NIR) wavelength. These near-ultraviolet (UV) emissions are associated with earlier stage electrical breakdown (e.g., streamers), may frequent intense regions of deep convective storms, and may be a significant source of nitrogen oxide production in the upper atmosphere. A new lightning mapping instrument called the CubeSat Lightning Imaging and Detection Experiment (CLIDE) is being designed at NASA Marshall Space Flight Center to use high-speed, scientific CMOS image sensors capable of detecting lightning’s transient optical emissions in the near-UV and NIR during both daylit and nighttime scenes. This will extend the record of global lightning activity and help pave the way for future small satellite missions that combine radio and optical lightning detectors to obtain novel three-dimensional maps of lightning on a global scale, which can revolutionize the way lightning is used to monitor weather and understand changes in climate.

lightning↗

NASA NTRSDate not supplied

3D Geolocation of Simulated Lightning Sources from Low-Earth Orbit

The recent removal of the Lightning Imaging Sensor from the International Space Station has left an observational gap in lightning detection from low-Earth orbit (LEO). However, new studies have demonstrated the potential for 3D geolocation of lightning sources using orbiting sensors. The Cubespark mission concept aims to take advantage of these developments by deploying a constellation of satellites with radio frequency (RF) sensors and optical imagers to not only map lightning locations, but also to collect bi-spectral flash images. These new capabilities include mapping storm charge structure, flash channel structure, and distinguishing microphysical processes throughout flash development, helping link microphysics and convective processes with overall flash and storm structure around the globe from LEO. In this study, we simulate lightning RF sources in the very high frequency (VHF) band, extrapolate their signals to space-based detection using an improved ionospheric model, and reconstruct their 3D locations using a time-of-arrival (TOA) minimization algorithm. Various constellation configurations, locations, and atmospheric conditions are considered in order to identify and quantify the three main sources of geolocation error: geometric, ionospheric, and instrumental effects. The promising results of this study emphasize the potential of space-based 3D lightning mapping under diverse conditions. 3D resolution is shown to be better than 1-2 km in many cases, enabling new global applications in meteorology and climate sciences. Here we present a selection of these geolocation results as seen from space alongside recent advancements, paving the way for a future generation of LEO lightning mappers.

CubeSpark↗

NASA NTRSDate not supplied

3D Lightning Geolocation with the CubeSpark Constellation

The new CubeSpark mission concept is being developed as a constellation of up to six satellites for high-resolution 3D lightning mapping. Each satellite in low-Earth orbit (LEO) will use optical and radio frequency (RF) sensors to geolocate individual sources from lightning flashes. The purpose of this study is to evaluate the potential accuracies and feasibilities of RF-based geolocation methods. This is done using a robust simulation framework to accurately depict the ionosphere’s effect on propagating RF signals, using their arrival times at each station to reconstruct source locations. We identified the primary sources of error as geometric, ionospheric, and instrumental. These are each analyzed to determine their quantitative effect on geolocation uncertainty. CubeSpark’s science objectives include mapping thundercloud charge regions and even individual flash channel structure for applications across a wide range of fields from climatology to hydrology. These applications require geolocation accuracy better than 1-2 km in each dimension, thus special care must be taken to optimize constellation design, minimize the main sources of error, and maximize CubeSpark’s potential. The algorithms developed in this study show promising results, with large regions having both horizontal and vertical uncertainties less than 1 km. After the removal of the Lightning Imaging Sensor from the International Space Station, an observational gap has been left for lightning observers from LEO. It therefore becomes increasingly vital to evaluate and improve on the current state of lightning mapping to prepare for the next generation of 3D lightning geolocation.

lightning↗

NASA NTRSDate not supplied

Overview of Lightning Science at NASA Marshall Space Flight Center

NASA Marshall Space Flight Center (MSFC) is a recognized world leader in the science of lightning. To date, MSFC has led three space-based global lightning observing missions and has helped lead multiple suborbital field campaigns involving lightning observations. Recently, the MSFC Lightning Team is closing out the recently completed International Space Station Lightning Imaging Sensor (ISS LIS) mission, including developing a nearly three-decade global climatology of lightning from space. This work also includes integrating lightning observations with data from NASA precipitation missions. The Team is also busy analyzing data from a recent airborne field campaign that observed dozens of terrestrial gamma-ray flashes (TGFs) from intense tropical thunderstorms. Lightning Team members are also leaders in validation of the Geostationary Lightning Mapper (GLM) operated by NOAA, and in developing lightning safety applications and studying the relationship between lightning and wildfires. The Lightning Team also studies chemical production by lightning and contributes to the National Climate Assessment (NCA). Finally, the Lightning Team is busy developing the next generation of spaceborne lightning sensors to broaden our understanding of the relationships between lightning, weather, climate, and atmospheric composition.

Timothy Lang↗

NASA NTRSDate not supplied

The Lightning Instrument Package

Explore the source record for details and available documents.

Christopher J Schultz↗

NASA NTRSDate not supplied

Space-based Sensor for Extreme Fire Weather Events

Catastrophic bushfires are becoming increasingly prevalent as climate change advances. Impacts extend beyond national borders. Multinational efforts can inform new science and management practices. Space-based sensors and integrated data facilities will play an important role. This paper describes a collaborative project between a consortium of Australian universities and NASA Centers to develop and implement a small satellite platform comprising highly integrated thermal and lightning sensors coupled with AI-based edge computing to help predict, detect, and track bushfires, supporting mitigation activities. This will fill an important capability gap since Australia does not currently have any sovereign Earth observation satellites. This program is enabled by and builds on Australia-NASA collaboration and will also support fire science and management activities in the broader global context.

wildfire↗

NASA NTRSDate not supplied

The Next Generation of Lightning Mapping

With the removal of the Lightning Imaging Sensor from the International Space Station, a gap has opened in lightning observation from low-Earth orbit. The CubeSpark mission concept aims to fill this role using a constellation of satellites with radio frequency (RF) sensors and bi-spectral optical imagers to observe lightning flashes more completely and with better resolution than is currently possible from space. In this study, we assess the feasibility of multiple methods of not only mapping lightning locations, but also inferring 3D flash and charge structures. This is done primarily by simulating lightning emissions in the very high frequency (VHF) band, modeling their propagation to orbital sensors, and reconstructing their locations using time-of-arrival (TOA) minimization algorithms. Constellation shape, number, and atmospheric conditions are varied in order to quantify the three main sources of geolocation error: geometric, ionospheric, and instrumental effects. The promising results presented here demonstrate 3D resolution better than 1-2 km in many cases, enabling new applications in meteorology and climate sciences.

CubeSpark↗

NASA NTRSDate not supplied

Reanalysis of Fly's Eye GLM Simulator (FEGS) Optical Pulse Detections from the 2017 GOES-R Post Launch Test (GOES-R PLT) Field Campaign

In 2017, the GOES-R PLT field campaign was conducted to validate new instruments on board GOES-16, including the Geostationary Lightning Mapper (GLM). A NASA ER-2 high altitude aircraft was equipped with a sensor suite including FEGS and an electric field change meter (EFCM) for complementary observations of lightning. As part of a modern reanalysis, we plan to combine aircraft and ground observations from the lightning instrumentation and polarimetric Doppler radars for a more complete characterization of optical lightning measurements in the context of convective properties. This presentation focuses on our initial efforts which include a reanalysis of the FEGS multi-spectral optical waveforms using an updated pulse detection algorithm and a comparison of detected pulses with coincident EFCM and Lightning Mapping Array (LMA) data. We will present on characteristics of discharge processes including leaders, strokes, and continuing current signatures as observed by the suite of aircraft and ground-based lightning instrumentation.

T Daniel Walker↗

NASA NTRSDate not supplied

A Field Campaign to Study Lightning that Ignites the Bush

The impact of recent wildland fires in the United States and Australia have received much attention in the past several years. As a result, NASA has developed a new Earth Science program to better understand, predict, and manage this phenomenon, as well as a future suborbital mission to studying pyro-cumulonimbus clouds and their effects on the Earth system. In Australia, government and philanthropic stakeholders are supporting a series of field campaigns over the next few years to inform science requirements and advance technology for a future satellite mission to monitor Bushfires. Lightning flashes are a major source of wildland fires, but uncertainties remain about the physical characteristics of lightning and their parent thunderstorms responsible for igniting wildfires. It was long believed that most lightning-ignited wildfires are largely caused by positive flashes to the ground (CGs) and multi-stroke CGs, but a recent study looking at 26-years of NLDN data indicate otherwise. Perhaps this finding is due to statistical chance—there are more negative CGs that occur globally—or perhaps there is some unknown electrical property of the thundercloud from which the igniting flashes emanate. Regardless, new observing strategies are needed. Additionally, long continuing current CGs, which are more likely to ignite a fire, can elude detection by operational ground-based lightning location systems, making it difficult to efficiently identify potential wildland fires and manage them before they have adverse impacts. To address these science and operational gaps, NASA’s Lightning Mapping Array along with electric and magnetic field change meters will be deployed for the Australian Bushfire campaign to document the electrical structure and properties of thunderstorms and lightning that occur in a wildland fire susceptible region. Another aspect of the campaign will be the use of NASA’s airborne lightning observatory, which includes a spectrometer and high-speed imager, to document the radiometric attributes of these flashes coincident with the ground-based RF observations. These observations will be used to better understand the properties of lightning that ignite wildland fires as well as inform design of a lightning detection system for the future Bushfire Monitoring satellite mission.

lightning↗

NASA NTRSDate not supplied

Using Optical Lightning Detection Data from the 2017 GOES-R Post Launch Test Field Campaign Flights as an Evaluation of Convective Processes

The primary mechanisms for thunderstorm electrification and lightning production are widely understood and allow connections between lightning intensity and occurrence to be used to derive storm strength and forecast the probability of related weather phenomena. However, these assumed relationships between lightning and convective properties were discovered primarily using ground-based lightning sensors and measurements, meaning the true depth of insight from space or air based detections is widely unexplored. In 2017, a field campaign was launched to validate the instrumentation aboard the GOES-16 satellite. It involved flying a NASA-ER2 aircraft over multiple storms across the continental US and it included the Fly’s Eye GLM Simulator (FEGS) as a proxy for the Geostationary Lightning Mapper (GLM). Utilizing the data from this field campaign, one of the main goals of this project is to investigate how attributes of convection impact optical lightning detection and the subsequent assumptions that can be made in relation to convective dynamics and precipitation microphysics. Hydrometeor identification, 3D winds retrieval, and additional radar and LiDAR data analysis will be utilized alongside FEGS and interferometer data in order to observe these relationships. This presentation will be to lay out the initial conclusions from our analysis and to explore any new insights or contradictions within our findings.

Kaitlyn Wheeler↗