NASA GHRC Collaboration between NASA MSFC and The University of Alabama in Huntsville
  • Access Data
    • Dataset List (HyDRO)
      • View a list of all GHRC dataset holdings using our custom search tool, HyDRO.
    • Search (HyDRO)
      • HyDRO is GHRC's custom dataset search and order tool.

        With HyDRO, you can search, discover, and filter GHRC's dataset holdings.

        HyDRO will also help you find information about browse imagery, access restrictions, and dataset guide documents.
    • CSE
      • The GHRC Coincidence Search Engine (CSE) may be used to search for times when up to four satellites were over or within the same geographic area simultaneously.

        Searches may be constrained by time, geographic area, and/or distance between the satellites.
    • THREDDS
      • This is our current OPeNDAP server.

        You can access, download, and subset selected datasets with THREDDS. You can also obtain WMS links and applicable documentation and browse images for some datasets.
    • Storm Tracks DB
      • The Tropical Storm Tracks database is derived from the storm data published by the National Hurricane Center (NHC).

        This web page provides a convenient user interface for casually browsing storm information, including location, category, and wind speed.
    • AMSU Temp Trends
      • Daily averaged temperatures of the Earth are measured by the Advanced Microwave Sounding Unit (AMSU) on NASA's Aqua satellite.
    • NASA Earthdata Search
      • Earthdata is NASA's next generation metadata and service discovery tool, providing search and access capabilities for dataset holdings at all of the Distributed Active Archive Centers (DAACs) including the GHRC.
    • Latest Data (HyDRO)
      • View the latest additions to our data holdings using HyDRO.
  • Measurements
    • Lightning
      • Lightning data from satellite, airborne and ground instruments.
    • Water Vapor & Precipitation
      • Precipitation, atmospheric water vapor and related measurements.
    • Temperature
      • Long term atmospheric temperature records from satellites; ground-based and airborne observations from satellites.
  • Field Campaigns
    • Hurricane Science
      • GHRC has worked with NASA's Hurricane Science Research Program (HSRP) since the 1990's. We are the archive and distribution center for data collected during HSRP field campaigns, as well as the recent Hurricane Science and Severe Storm Sentinel (HS3) Earth Venture mission. Field campaigns provide for intensive observation of specific phenomena using a variety of instruments on aircraft, satellites and surface networks.

        GHRC also hosts a database of Atlantic and Pacific tropical storm tracks derived from the storm data published by the National Hurricane Center (NHC).
    • HS3
      • Hurricane and Severe Storm Sentinel (HS3) is a NASA airborne field campaign aimed at better understanding the physical processes that control hurricane intensity change, addressing questions related to the roles of environmental conditions and internal storm structures to storm intensification.

        A variety of in-situ, satellite observations, airborne data, meteorological analyses, and simulation data were collected with missions over the Atlantic in August and September of three observation years (2012, 2013, 2014). These data are available at GHRC beginning in 2015.
    • GRIP (2010)
      • The Genesis and Rapid Intensification Processes (GRIP) experiment was a NASA Earth science field experiment in 2010 that was conducted to better understand how tropical storms form and develop into major hurricanes.

        The GRIP deployment was 15 August – 30 September 2010 with bases in Ft. Lauderdale, FL for the DC-8, at Houston, TX for the WB-57, and at NASA Dryden Flight Research Facility, CA for the Global Hawk.
    • TC4 (2007)
      • The NASA TC4 (Tropical Composition, Cloud and Climate Coupling) mission investigated the structure and properties of the chemical, dynamic, and physical processes in atmosphere of the tropical Eastern Pacific.

        TC4 was based in San Jose, Costa Rica during July 2007.

        The Real Time Mission Monitor provided simultaneous aircraft status for three aircraft during the TC4 experiment. During TC4, the NASA ER-2, WB-57 and DC-8 aircraft flew missions at various times. The science flights were scheduled between 17 July and 8 August 2007.
    • NAMMA (2006)
      • The NASA African Monsoon Multidisciplinary Analyses (NAMMA) campaign was a field research investigation based in the Cape Verde Islands, 350 miles off the coast of Senegal in west Africa.

        Commenced in August 2006, NASA scientists employed surface observation networks and aircraft to characterize the evolution and structure of African Easterly Waves (AEWs) and Mesoscale Convective Systems over continental western Africa, and their associated impacts on regional water and energy budgets.
    • TCSP (2005)
      • The Tropical Cloud Systems and Processes (TCSP) mission was an Earth science field research investigation focused on the study of the dynamics and thermodynamics of precipitating cloud systems and tropical cyclones. TCSP was conducted during the period July 1-27, 2005 out of the Juan Santamaria Airfield in San Jose, Costa Rica.

        The TCSP field experiment flew 12 NASA ER-2 science flights, including missions to Hurricanes Dennis and Emily, Tropical Storm Gert and an eastern Pacific mesoscale complex that may possibly have further developed into Tropical Storm Eugene.
    • ACES (2002)
      • The Altus Cumulus Electrification Study (ACES) was aimed at better understanding the causes and effects of electrical storms.

        Based at the Naval Air Station Key West in Florida, researchers in August 2002 chased down thunderstorms using an uninhabited aerial vehicle, or "UAV", allowing them to achieve dual goals of gathering weather data safely and testing new aircraft technology. This marked the first time a UAV was used to conduct lightning research.
    • CAMEX-4 (2001)
      • The Convection And Moisture EXperiment (CAMEX) was a series of NASA-sponsored hurricane science field research investigations. The fourth field campaign in the CAMEX series (CAMEX-4) was held in 16 August - 24 September, 2001 and was based out of Jacksonville Naval Air Station, Florida.

        CAMEX-4 was focused on the study of tropical cyclone (hurricane) development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.
    • CAMEX-3 (1998)
      • The Convection And Moisture EXperiment (CAMEX) is a series of hurricane science field research investigations sponsored by NASA. The third field campaign in the CAMEX series (CAMEX-3) was based at Patrick Air Force Base, Florida from 6 August - 23 September, 1998.

        CAMEX-3 successfully studied Hurricanes Bonnie, Danielle, Earl and Georges, yielding data on hurricane structure, dynamics, and motion. CAMEX-3 collected data for research in tropical cyclone development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.
    • GPM Ground Validation
      • The NASA Global Precipitation Measurement Mission (GPM) Ground Validation (GV) program includes the following field campaigns:

        a) LPVEx, Gulf of Finland in autumn 2010, to study rainfall in high latitude environments

        b) MC3E, cental Oklahoma spring and early summer 2011, to develop a complete characterization of convective cloud systems, precipitation and the environment

        c) GCPEx, Ontario, Canada winter of 2011-2012, direct and remove sensing observations, and coordinated model simulations of precipitating snow.

        d) IFloodS, Iowa, spring and early summer 2013, to study the relative roles of rainfall quantities and other factors in flood genesis.

        e) IPEx, N. Carolina Appalachians/Piedmont region May-June 2014, for hydrologic validation over varied topography.

        f) OLYMPEx, Washington's Olympic Peninsula scheduled November 2015-February 2016, for hydrologic validation in extreme coastal and topographic gradients
    • OLYMPEX (Upcoming)
      • The OLYMPEX field campaign is scheduled to take place between November, 2015, and February, 2016, on the Olympic Peninsula in the Pacific Northwest of the United States.

        This field campaign will provide ground-based validation support of the Global Precipitation Measurement (GPM) satellite program that is a joint effort between NASA and the NASDA space agency of Japan.

        As for all GPM-GV campaigns, the GHRC will provide a collaboration portal to help investigators exchange planning information, and to support collection of real-time data as well as mission science, project and instrument status reports during the campaign.
    • IPHEx (2014)
      • The Integrated Precipitation and Hydrology Experiment (IPHEx) was conducted in North Carolina during the months of April-June, 2014.

        IPHEx sought to characterize warm season orographic precipitation regimes, and the relationship between precipitation regimes and hydrologic processes in regions of complex terrain.
    • IFLOODs (2013)
      • The Iowa Flood Studies (IFloodS) experiment was conducted in the central to northeastern part of Iowa in Midwestern United States during the months of April-June, 2013.

        IFloodS' primary goal was to discern the relative roles of rainfall quantities such as rate and accumulation as compared to other factors (e.g. transport of water in the drainage network) in flood genesis.
    • GCPEX (2011-2012)
      • The GPM Cold-season Precipitation Experiment (GCPEx) occurred in Ontario, Canada during the winter season (Jan 15- Feb 26) of 2011-2012.

        GCPEx addressed shortcomings in GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. Collectively the GCPEx data set provides a high quality, physically-consistent and coherent data set suited to the development and testing of GPM snowfall retrieval algorithm physics.
    • MC3E (2011)
      • The Mid-latitude Continental Convective Clouds Experiment (MC3E) took place in central Oklahoma during the April–June 2011 period.

        The overarching goal was to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that had never before been available.
    • LPVEx (2010)
      • The Light Precipitation Evaluation Experiment (LPVEx) took place in the Gulf of Finland in September and October, 2010 and collected microphysical properties, associated remote sensing observations, and coordinated model simulations of high latitude precipitation systems to drive the evaluation and development of precipitation algorithms for current and future satellite platforms.

        In doing so, LPVEx sought to address the general lack of dedicated ground-validation datasets from the ongoing development of new or improved algorithms for detecting and quantifying high latitude rainfall
  • Projects
    • HS3
      • Hurricane and Severe Storm Sentinel (HS3) is a NASA airborne field campaign aimed at better understanding the physical processes that control hurricane intensity change, addressing questions related to the roles of environmental conditions and internal storm structures to storm intensification.
    • DISCOVER - MEaSUREs
      • DISCOVER was funded by NASA’s MEaSUREs program to provide highly accurate, multi-decadal geophysical products derived from satellite microwave sensors.
    • LIS
      • Lightning observations from the Lightning Imaging Sensors (LIS) aboard the NASA’s TRMM satellite and International Space Station, as well as airborne observations and ground validation data.
    • SANDS
      • The SANDS project addressed Gulf of Mexico Alliance priority issues by generating enhanced imagery from MODIS and Landsat data to identify suspended sediment resulting from tropical cyclones. These tropical cyclones have significantly altered normal coastal processes and characteristics in the Gulf region through sediment disturbance.
  • Resources
    • Tools & Technologies
      • A collection of tools & technologies developed and/or used by GHRC.
    • Publications
      • View GHRC & ITSC publications on the ITSC website
    • Innovations Lab
      • The GHRC Innovations Lab is a showcase for emerging geoinformatics technologies resulting from NASA-sponsored research at the University of Alabama in Huntsville.
    • Educational Resources
      • A list of resources from NASA, MSFC, and other sources for teachers and students focused on global change, hydrology, and science education.
    • Referencing our data
      • GHRC dataset citation help and examples.
    • Documents
      • Documentation related to GHRC datasets, software, and other offerings.
  • Multimedia
  • About
    • Welcome
      • Local resources, lodging information, and weather to help you plan your visit to GHRC.
    • GHRC Personnel
      • A list to help you keep in touch with our personnel
    • FAQ
      • Frequently Asked Questions about GHRC data and services, and their answers.
    • Glossary
      • Terms and their definitions
    • Referencing our data
      • GHRC dataset citation help and examples
  • Cite Us
  • Contact Us
Lightning & Atmospheric Electricity Research

Lightning Home

The Lightning Team

A Lightning Primer

File Cabinet and Bookshelf

 

Global Lightning Image
Global Lightning Image
Global lightning strikes from January 1998 to present day from the NASA/MSFC Lightning Imaging Sensor

A Lightning Primer

Investigations Using Rockets, High-Altitude Airplanes & Spacecraft

For many investigations, lightning must be observed from as close a vantage point as possible. One technique is to probe inside hostile thunderstorms in order to study how thunderclouds electrify, but this does not ensure close-up encounters with lightning. Close-up measurements are difficult to obtain because of the unpredictability of where and when lightning will strike. Hence, methods have been developed to create lightning discharges under somewhat controlled conditions.

Rocket-triggered lightning research has been an important tool lightning for close-up investigation.

With this technique, small sounding rockets connected to long copper wires have replaced Franklin's kite. These rockets are launched into thunderstorms with electronic sensors located near the bottom end of the wire instead of a key. When the rocket is struck by lightning, the wire is vaporized.

Data collected before and during the occurrence of lightning provide detailed information of the discharge's characteristics. Sounding rockets can also provide in-cloud measurements of thunderstorms in a challenging environment. While extensive ground based optical and electrical measurements of lightning have been made, the emphasis has been on cloud-to-ground discharges with little study of intra-cloud lightning being undertaken. This is partly due to the fact that optical measurements of in-cloud lightning are severely affected by light scattering from water droplets within the cloud. For this reason, ground-based measurements alone have not been considered an appropriate means for determining the optical characteristics of lightning as viewed from above.

ER-2 In order to determine the requirements for making optical measurements from space, U-2 and ER-2 high altitude airplanes have been used to study the electrical and optical characteristics of lightning activity in thunderstorms. Flying at an altitude of 20 km and at speeds of 200 meters per second, they are capable of flying over very large thunderstorms.

Much has been learned from these aircraft observations. For example, they have confirmed C. T. R. Wilson's theory that strong electric fields over the tops of thunderstorms cause conduction currents to flow to the tops of clouds. The penetrative convective cells which rise above the anvil are the most active electric regions in the storm and cause the most intense electrical stresses, as seen from high altitude aircraft.

ER-2 Configuration for Storm Observations

The ER-2 has a larger payload capability than its predecessor the U-2. Both have provided direct observations of severe thunderstorms and other clouds using multi-sensor payloads including lasers, infrared, visible and microwave scanners, spectrometers, and electric field antennas.

Lightning Image from above clouds In addition, photography of lightning from above clouds has been accomplished using an open shutter technique. In this method, the camera is pointed toward the thundercloud with the shutter open. In the dark nocturnal sky, no light falls onto the film until lightning strikes. An example of an open shutter photograph from the U-2 is shown on the left. The illuminated storm cell depicts a convective cloud turret approximately 11 km in height and 12 km in diameter.

To complement the optical measurements from aircraft, video lightning images have been taken during a number of space shuttle flights while conducting the Mesoscale Lightning Observation Experiment (MLE). These observations have revealed many interesting lightning events.

For example, on April 28, 1990, a video image from space showed a single stratospheric luminous discharge appearing to move upward into clear night air. This was recorded on the space shuttle STS-32 mission using the payload bay TV camera.

The direction of this event has not been firmly established, however, the stratospheric discharge is of interest because it may provide evidence for a theory postulated by C. T. R. Wilson Lightning discharge process in 1925. This theory predicted that electric fields can cause ionization at great heights and could therefore give rise to discharges between clouds and the upper atmosphere.

Stratospheric lightning could potentially deposit significant energy into the stratosphere, causing important chemical perturbations. In addition, these lightning events may generate strong electric fields and electromagnetic pulses which might interact with the Earth's ionosphere and magnetosphere. Finally, strong fields at high altitudes may generate runaway electrons which could then produce high energy x-rays and even gamma rays. Thus, it is possible that lightning may generate electromagnetic radiation, ranging from extremely low frequency to gamma radiation.

Researchers from the Geophysical Institute at the University of Alaska have confirmed shuttle observations by capturing images on videotape of what appear to be brief flashes of light emanating from thunderstorms into the stratosphere. These "stratospheric optical flashes", also known as "red sprites", were photographed from NASA's DC-8 Airborne Laboratory while flying at an altitude of about l2 km during a night-time mission to videotape lightning over Iowa and Kansas during June and July of 1993. Stratospheric flashes are brief, persisting for less than about a tenth of a second. They appear to be associated with intense thunderstorm activity, but are both rare and fainter than typical cloud-to-ground or intra-cloud lightning. Unlike familiar ground level lightning events that are electrical discharges confined to narrow channels, the flashes appear to cover a relatively broad horizontal extent of several miles, and to extend to altitudes of perhaps as much as 95 km, or about 60 miles.

Lightning Detection Networks (Ground Based)

National and regional lightning networks which use magnetic direction finders, time of arrival techniques, or VHF interferometry, provide important lightning and storm information. For a number of years, the Federal Government assisted in the financing of a national lightning data service combining independently operated systems into one network. Used primarily for operational evaluation by NOAA, it evolved into a product with substantial value for both private industry and by other Federal agencies. By 1991, recognition of the importance of lightning detection had become apparent with economically viable commercially-sponsored systems coming into existence.

Lightning Dectector The National Lightning Detection Network (NLDN) which is operated by Global Atmospherics, Inc. (GAI) in Tucson, Arizona, is a network of at least 130 magnetic direction finders which covers the entire United States. Each direction finder determines a direction toward a detected electromagnetic lightning discharge. The location of the lightning discharge is determined by triangulation. Each of these sensors is capable of detecting cloud-to-ground lightning flashes at a distance of 400 km away and greater. Processed information is transmitted to the Network Control Center (NCC) in the form of a grid map showing lightning across the U.S.

The Atmospheric Research Systems, Inc. (ARSI) time-of-arrival (TOA) system provides 11 Lightning Position And Tracking Systems (LPATS) which cover the U.S. and extend hundreds of miles into both oceans and beyond the borders of Canada and Mexico. ARSI ground strokes lightning data includes information on latitude and longitude, date and time, polarity, and amplitude.

Recently, GDS purchased the ARSI system, and is in the process of combining the direction finding and time of arrival techniques into a single comprehensive network.

NLDN Sensor Map The TOA system operates by digitizing the waveform of a received lightning signal at each sensor and accurately timing the peak with a resolution of up to 100 nanoseconds. The difference of arrival time at four or more receivers is then used to calculate the location. The geographical positions of the various sensors making up the network are shown in the U.S. map.

Internationally, two very different types of lightning detection and location networks have been developed. The SAFIR two-dimensional VHF interferometer system developed by the French aerospace research organization ONERA and commercialized by Dimensions of France, is used to provide detailed information on all types of lightning activity within a relatively small area. The VLF Arrival-Time Difference (ATD) system designed and operated by the United Kingdom Meteorological Office, detects and locates lightning at very long range, but with less detection efficiency. In addition, other networks cover portions of Europe, Asia, Australia, China, and Canada.

Global Studies

Lightning and Cloud Global lightning signatures from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) have been analyzed from the filmstrip imagery which is archived at the National Snow and Ice Data Center in Boulder, Colorado. These signatures show up as horizontal streaks on the film images. The location of each of these streaks has been digitized in order to develop a preliminary database of global lightning activity.

While the database continues to be enlarged, the available data are spotty, making a comprehensive history of global lightning behavior impossible to produce. However, direct digital OLS data are becoming available now which will greatly improve and expand the global lightning database which is an important reference dataset.

Lightning annual, interannual , and seasonal variations could then be compared with other global datasets (e.g. precipitation; global and regional synoptic patterns) both to improve understanding of the role of lightning on a global basis and to use lightning as an indicator of global change.

The Global Electric Circuit

Global Electric Circuit During fair weather, a potential difference of 200,000 to 500,000 Volts exists between the Earth's surface and the ionosphere, with a fair weather current of about 2x10-12 amperes/meter2. It is widely believed that this potential difference is due to the world-wide distribution of thunderstorms.

Present measurements indicate that an average of almost 1 ampere of current flows into the stratosphere during the active phase of a typical thunderstorm. Therefore, to maintain the fair weather global electric current flowing to the surface, one to two thousand thunderstorms must be active at any given time. While present theory suggests that thunderstorms are responsible for the ionospheric potential and atmospheric current for fair weather, the details are not fully understood.

Ground-based radio frequency measurements of global rates have significant uncertainties and limitations. A high resolution space based sensor is necessary in order to help eliminate some of the present uncertainties associated with measuring global lightning activity.

The OTD is a highly compact combination of optical and electronic elements. It was developed as an in-house project at NASA's Marshall Space Flight Center in Huntsville, Alabama. The name, Optical Transient Detector, refers to its capability to detect the momentary changes in an optical scene which indicates the occurrence of lightning. The OTD instrument is a major advance over previous technology in that it can gather lightning data under daytime conditions as well as at night. In addition, it provides much higher detection efficiency and spatial resolution than has been attained by earlier lightning sensors.

At the heart of the system is a solid-state optical sensor similar in some ways to a TV camera. However, in overall design and many specific features, OTD had to be uniquely designed for the job of observing and measuring lightning from space. Like a TV camera, the OTD has a lens system, a detector array (serving a function somewhat analogous to the retina in the human eye), and circuitry to convert the electronic output of the system's detector array into useful data.

Further Information:

OTD Homepage

Tropical Rainfall Measuring Mission (TRMM)

Rainfall is at the heart of Earth's unique ability to sustain life as we know it. Vegetable, animal, and human life is controlled to a large degree by the availability of moisture. On the global scale, heat released by the condensation of water vapor is a principal cause of motion in the atmosphere. Tropical rainfall, due to its abundance, plays a significant role in this process.

The measurement of rainfall is a difficult challenge due to its high spatial and temporal variability. Tropical rainfall is especially difficult as it is relatively inaccessible to in situ measurements.

Launched in November, 1997, TRMM is a space based system for measuring tropical rainfall and its variations. Its orbit is circular, at an inclination of 35 degrees to the equator, and at an altitude of 350 km. The low altitude of TRMM provides high resolution images, thus, more accurate rainfall measurements are obtained over very small areas of the globe.

TRMM is an international collaboration with Japan, providing the first Precipitation Radar (PR) in space. The PR instrument provides information on 3-D rainfall distributions over both land and ocean.

A multichannel microwave radiometer, referred to as the TRMM Microwave Imager (TMI), provides information on precipitation content, and the real distribution and intensity of rainfall.

The Visible InfraRed Scanner (VIRS) provides high resolution information on cloud coverage and type, and cloud top temperatures.

The Clouds and the Earth's Radiant Energy System (CERES) is a visible and infrared sensor designed especially to measure emitted and reflected radiative energy from the Earth, and from the atmosphere and its constituents.

The Lightning Imaging Sensor (LIS) is investigating the global incidence of lightning and the relationship of lightning to precipitation and other geophysical parameters.

Further Information:

TRMM NASAFact Sheet
Tropical Rainfall Measuring Mission (TRMM)

 

Lightning Imaging Sensor (LIS)

Lightning Imaging Sensor

This instrument, flying on the TRMM Observatory, was designed to study the distribution and variability of total lightning on a global basis. It consists of a staring imager which is optimized to locate and detect lightning with storm-scale resolution of 5-10 km over a large region (600 x 600 km) of the Earth's surface. The field of view (FOV) is sufficient to observe a point on the Earth or a cloud for 80 seconds, adequate to estimate the flashing rate of many storms. The instrument records the time of occurrence of a lightning event, measures the radiant energy, and estimates the location.

This calibrated lightning sensor uses a wide FOV expanded optics lens with a narrow-band filter in conjunction with a high speed charge-coupled device detection array. A Real-Time Event Processor (RTEP) is used to determine when a lightning flash occurs, even in the presence of bright sunlit clouds.

Weak lightning signals that occur during the day are hard to detect because of background illumination. The RTEP will remove the background signal, thus enabling the system to detect weak lightning and achieve a 90% detection efficiency.

TRMM will study mesoscale phenomena such as storm convection, dynamics, and microphysics. These will be related to global rates and amounts and distribution of convective precipitation, as well as to the release and transport of latent heat, which are all influenced by global scale processes.

LIS contributes significantly to several TRMM mission objectives by providing a global lightning and thunderstorm climatology from which changes (even subtle temperature variations) might be easily detected.

Further Information:

LIS Homepage

Christian, H.J., R.J. Blakeslee, and S.J. Goodman, The Detection of Lightning from Geostationary Orbit, Journal of Geophysical Research, Vol. 94, 13,329-13,337, 1989.

Christian, H.J., R.J. Blakeslee, and S.J. Goodman, Lightning Imaging Sensor (LIS) for the Earth Observing System, NASA Technical Memorandum 4350, MSFC, Huntsville, AL, February, 1992.

 

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