Lightning stroke data from the National Lightning Detection Network (NLDN) for particular periods during the IMPACTS_2022 campaign. Data are available for 14-15, 17-20, and 28-31 January as well as 4-5, 12-13, 17-20, and 24-26 February 2022.

The National Lightning Detection Network, NLDN, consists of over 100 remote, ground-based sensing stations located across the United States that instantaneously detect the electromagnetic signals given off when lightning strikes the earth's surface. These remote sensors send the raw data via a satellite-based communications network to the Network Control Center operated by Vaisala Inc. in Tucson, Arizona. Within seconds of a lightning strike, the NCC's central analyzers process information on the location, time, polarity, and communicated to users across the country.

More information:
http://thunderstorm.vaisala.com

This password protected dataset contains the Vaisala National Lightning Detection Network (NLDN) data for the region from 28-49 N and 75-103W during the PLOWS 2009-2010 field season (November 2009 to 10 March 2010). These data contain NLDN lightning stroke data with the following parameters: date, time, latitude, longitude, polarity and peak current. This dataset was made available from Vaisala, Inc. free of charge to PLOWS investigators ONLY and all users are required to abide by the Vaisala NLDN data policy to researchers: 1) Lightning data supplied by Vaisala may not be used for direct comparisons with other lightning detection networks, unless approved by the Development Center for Meteorology. This is to ensure proper lightning data interpretation, proper analysis techniques and the appropriateness of the lightning dataset to be used in comparisons. 2) Prior to submission of any publication employing data provided under this policy, Vaisala must be given the opportunity to look over elements of the manuscript related to Vaisala data for technical accuracy. Vaisala will also be open to assisting the authors by providing additional technical details if so desired by both Vaisala and the authors. Vaisala must be acknowledged as the source of the information and data. 3) There can be no proprietary or commercial restrictions on the research results, and the investigator(s) must be directly associated with an academic or research organization. 4) Archival of the data is allowed, but the data will not be shared with or sold to another party without Vaisala's expressed permission. Before access can be granted, the user must fill out and sign the Vaisala Lightning Data Research Policy to signify their agreement with these terms. The agreement is available online: http://www.eol.ucar.edu/projects/plows/documents/Vaisala_Lightning_Data_Research_Policy.pdf When completed and signed the form should be sent to: Steve Williams NCAR/EOL P.O. Box 3000 Boulder, CO 80307...

This dataset contains cloud-to-ground lightning strike information collected by Vaisala's National Lightning Detection Network and aggregated into 0.1 x 0.1 degree tiles by the experts at the National Centers for Environmental Information (NCEI) as part of their Severe Weather Data Inventory. This data provides historical cloud-to-ground data aggregated into tiles that around roughly 11 KMs for redistribution. This provides users with the number of lightning strikes each day, as well as the center point for each tile. The sample queries below will help you get started using BigQuery's GIS capabilities to analyze the data. For more on BigQuery GIS, see the documentation available here. The data begins in 1987 and runs through current day, with a delay of a few days for processing. For near real-time lightning information, see the Cloud Public Data's metadata listing of GOES-16 data for cloud-to-cloud and cloud-to-ground strikes over the eastern half of the western hemisphere. GOES-17 data covering the western half of the western hemisphere will be available soon. This public dataset is hosted in Google BigQuery and is included in BigQuery's 1TB/mo of free tier processing. This means that each user receives 1TB of free BigQuery processing every month, which can be used to run queries on this public dataset. Watch this short video to learn how to get started quickly using BigQuery to access public datasets. What is BigQuery .

Last Revised: February 2016

Map Information

This nowCOAST™ time-enabled map service provides maps of lightning strike density data from the NOAA/National Weather Service/NCEP's Ocean Prediction Center (OPC) which emulate (simulate) data from the future NOAA GOES-R Global Lightning Mapper (GLM). The purpose of this product is to provide mariners and others with enhanced "awareness of developing and transitory thunderstorm activity, to give users the ability to determine whether a cloud system is producing lightning and if that activity is increasing or decreasing..." Lightning Strike Density, as opposed to display of individual strikes, highlights the location of lightning cores and trends of increasing and decreasing activity. The maps depict the density of lightning strikes during a 15 minute time period at an 8 km x 8 km spatial resolution. The lightning strike density maps cover the geographic area from 25 degrees South to 80 degrees North latitude and from 110 degrees East to 0 degrees West longitude. The map units are number of strikes per square km per minute multiplied by a scaling factor of 10^3. The strike density is color coded using a color scheme which allows the data to be easily seen when overlaid on GOES imagery and to distinguish areas of low and high density values. The maps are updated on nowCOAST™ approximately every 15 minutes. The latest data depicted on the maps are approximately 12 minutes old (or older). Given the spatial resolution and latency of the data, the data should NOT be used to activite your lightning safety plans. Always follow the safety rule: when you first hear thunder or see lightning in your area, activate your emergency plan. If outdoors, immediately seek shelter in a substantial building or a fully enclosed metal vehicle such as a car, truck or van. Do not resume activities until 30 minutes after the last observed lightning or thunder. For more detailed information about layer update frequency and timing, please reference the
nowCOAST™ Dataset Update Schedule.

Background Information

The source for the data is OPC's gridded lightning strike density data on an 8x8 km grid. The gridded data emulate the spatial resolution of the future Global Lightning Mapper (GLM) instrument to be flown on the NOAA GOES-R series of geostationary satellites, with the first satellite scheduled for launch in late 2016.

The gridded data is based on data from Vaisala's ground based U.S. National Lightning Detection Network (NLDN) and its global lightning detection network referred to as the Global Lightning Dataset (GLD360). These networks are capable of detecting cloud-to-ground strikes, cloud-to-ground flash information and survey level cloud lightning information. According to the National Lightning Safety Institute, NLDN uses radio frequency detectors in the spectrum 1.0 kHz through 400 kHz to measure energy discharges from lightning as well as approximate distance and direction. According to Vaisala, the GLD360 network is capable of a detection efficiency greater than 70% over most of the Northern Hemisphere with a median location accuracy of 5 km or better. OPC's gridded data are coarser than the original source data from Vaisala's networks. The 15-minute gridded source data are updated at OPC every 15 minutes at 10 minutes past the valid time.

The lightning strike density product from NWS/NCEP/OPC is considered a derived product or Level 5 product ("NOAA-generated products using lightning data as input but not displaying the contractor transmitted/provided lightning data") and is appropriate for public distribution.

Time Information

This map service is time-enabled, meaning that each individual layer contains time-varying data and can be utilized by clients capable of making map requests that include a time component.

In addition to ArcGIS Server REST access, time-enabled OGC WMS 1.3.0 access is also provided by this service.

This particular service can be queried with or without the use of a time component. If the time parameter is specified in a request, the data or imagery most relevant to the provided time value, if any, will be returned. If the time parameter is not specified in a request, the latest data or imagery valid for the present system time will be returned to the client. If the time parameter is not specified and no data or imagery is available for the present time, no data will be returned.

This service is configured with time coverage support, meaning that the service will always return the most relevant available data, if any, to the specified time value. For example, if the service contains data valid today at 12:00 and 12:10 UTC, but a map request specifies a time value of today at 12:07 UTC, the data valid at 12:10 UTC will be returned to the user. This behavior allows more flexibility for users, especially when displaying multiple time-enabled layers together despite slight differences in temporal resolution or update frequency.

When interacting with this time-enabled service, only a single instantaneous time value should be specified in each request. If instead a time range is specified in a request (i.e. separate start time and end time values are given), the data returned may be different than what was intended.

Care must be taken to ensure the time value specified in each request falls within the current time coverage of the service. Because this service is frequently updated as new data becomes available, the user must periodically determine the service's time extent. However, due to software limitations, the time extent of the service and map layers as advertised by ArcGIS Server does not always provide the most up-to-date start and end times of available data. Instead, users have three options for determining the latest time extent of the service:

  Issue a returnUpdates=true request (ArcGIS REST protocol only)
  for an individual layer or for the service itself, which will return
  the current start and end times of available data, in epoch time format
  (milliseconds since 00:00 January 1, 1970). To see an example, click on
  the "Return Updates" link at the bottom of the REST Service page under
  "Supported Operations". Refer to the
  ArcGIS REST API Map Service Documentation
  for more information.


  Issue an Identify (ArcGIS REST) or GetFeatureInfo (WMS) request against
  the proper layer corresponding with the target dataset. For raster
  data, this would be the "Image Footprints with Time Attributes" layer
  in the same group as the target "Image" layer being displayed. For
  vector (point, line, or polygon) data, the target layer can be queried
  directly. In either case, the attributes returned for the matching
  raster(s) or vector feature(s) will include the following:


      validtime: Valid timestamp.


      starttime: Display start time.


      endtime: Display end time.


      reftime: Reference time (sometimes referred to as
      issuance time, cycle time, or initialization time).


      projmins: Number of minutes from reference time to valid
      time.


      desigreftime: Designated reference time; used as a
      common reference time for all items when individual reference
      times do not match.


      desigprojmins: Number of minutes from designated
      reference time to valid time.




  Query the nowCOAST™ LayerInfo web service, which has been created to
  provide additional information about each data layer in a service,
  including a list of all available "time stops" (i.e. "valid times"),
  individual timestamps, or the valid time of a layer's latest available
  data (i.e. "Product Time"). For more information about the LayerInfo
  web service, including examples of various types of requests, refer to
  the 
  nowCOAST™ LayerInfo Help Documentation

References

Kithil, 2015: Overview of Lightning Detection Equipment, National
Lightning Safety Institute, Louisville, CO. (Available from
http://www.lightningsafety.com/nsli_ihm/detectors.html).


NASA and NOAA, 2014: Geostationary Lightning Mapper (GLM). (Available at
http://www.goes-r.gov/spacesegment/glm.html).


NWS, 2013: Lightning Strike Density Product Description Document.
NOAA/NWS/NCEP/Ocean Prediction Center, College Park, MD (Available at
http://www.opc.ncep.noaa.gov/lightning/lightning_pdd.php
and http://products.weather.gov/PDD/Experimental%20Lightning%20Strike%20Density%20Product%2020130913.pdf).


NOAA Knows Lightning. NWS, Silver Spring, MD (Available at
http://www.lightningsafety.noaa.gov/resources/lightning3_050714.pdf).


Siebers, A., 2013: Soliciting Comments until June 3, 2014 on an
Experimental Lightning Strike Density product (Offshore Waters). Public
Information Notice, NOAA/NWS Headquarters, Washington, DC (Available at
http://www.nws.noaa.gov/om/notification/pns13lightning_strike_density.htm).

Map Information This nowCOAST time-enabled map service provides maps of experimental lightning strike density data from the NOAA/National Weather Service/NCEP's Ocean Prediction Center (OPC) which emulate (simulate) data from the future NOAA GOES-R Global Lightning Mapper (GLM). The purpose of this experimental product is to provide mariners and others with enhanced "awareness of developing and transitory thunderstorm activity, to give users the ability to determine whether a cloud system is producing lightning and if that activity is increasing or decreasing..." Lightning Strike Density, as opposed to display of individual strikes, highlights the location of lightning cores and trends of increasing and decreasing activity. The maps depict the density of lightning strikes during a 15 minute time period at an 8 km x 8 km spatial resolution. The lightning strike density maps cover the geographic area from 25 degrees South to 80 degrees North latitude and from 110 degrees East to 0 degrees West longitude. The map units are number of strikes per square km per minute multiplied by a scaling factor of 10^3. The strike density is color coded using a color scheme which allows the data to be easily seen when overlaid on GOES imagery and to distinguish values at low density values. The maps are updated on nowCOAST approximately every 15 minutes. The latest data depicted on the maps are approximately 12 minutes old (or older). The OPC lightning strike density product is still experimental and may not always be available. Given the spatial resolution and latency of the data, the data should NOT be used to activite your lightning safety plans. Always follow the safety rule: when you first hear thunder or see lightning in your area, activate your emergency plan. If outdoors, immediately seek shelter in a substantial building or a fully enclosed metal vehicle such as a car, truck or a van. Do not resume activities until 30 minutes after the last observed lightning or thunder. For more detailed information about the update schedule for the lightning strike density data maps on nowCOAST, please see: http://new.nowcoast.noaa.gov/help/#section=updateschedule Background Information The source for the data is OPC's gridded lightning strike density data on an 8 x 8 km grid. The gridded data emulate the spatial resolution of the future Global Lightning Mapper (GLM) instrument to be flown on the NOAA GOES-R series of geostationary satellites, with the first satellite scheduled for launch in early 2016. The gridded data is based on data from Vaisala's ground based Vaisala's U.S. National Lightning Detection Network (NLDN) and its global lightning detection network referred to as the Global Lightning Dataset (GLD360). These networks are capable of detecting cloud-to-ground strokes, cloud-to-ground flash information and survey level cloud lightning information. According to the National Lightning Safety Institute, NLDN uses radio frequency detectors in the spectrum 1.0 kHz through 400 kHz to measure energy discharges from lightning as well as approximate distance and direction. According to Vaisala, the GLD360 network is capable of a detection efficiency greater than 70% over most of the Northern Hemisphere with a median location accuracy of 5 km or better. OPC's experimental gridded data are coarser than the original source data from Vaisala's networks. The 15-minute gridded source data are updated at OPC every 15 minutes at 10 minutes past the valid time. The lightning strike density product from NWS/NCEP/OPC is considered a derived product or Level 5 product ("NOAA-generated products using lightning data as input but not displaying the contractor transmitted/provided lightning data") and is appropriate for public distribution. Time Information

This map is time-enabled, meaning that each individual layer contains time-varying data and can be utilized by clients capable of making map requests that include a time component.

This particular service can be queried with or without the use of a time component. If the time parameter is specified in a request, the data or imagery most relevant to the provided time value, if any, will be returned. If the time parameter is not specified in a request, the latest data or imagery valid for the present system time will be returned to the client. If the time parameter is not specified and no data or imagery is available for the present time, no data will be returned.

In addition to ArcGIS Server REST access, time-enabled OGC WMS 1.3.0 access is also provided by this service.

Due to software limitations, the time extent of the service and map layers displayed below does not provide the most up-to-date start and end times of available data. Instead, users have three options for determining the latest time information about the service:

Issue a returnUpdates=true request for an individual layer or for the service itself, which will return the current start and end times of available data, in epoch time format (milliseconds since 00:00 January 1, 1970). To see an example, click on the "Return Updates" link at the bottom of this page under "Supported Operations". Refer to the ArcGIS REST API Map Service Documentation for more information.

Issue an Identify (ArcGIS REST) or GetFeatureInfo (WMS) request against the proper layer corresponding with the target dataset. For raster data, this would be the "Image Footprints with Time Attributes" layer in the same group as the target "Image" layer being displayed. For vector (point, line, or polygon) data, the target layer can be queried directly. In either case, the attributes returned for the matching raster(s) or vector feature(s) will include the following:

validtime: Valid timestamp.

starttime: Display start time.

endtime: Display end time.

reftime: Reference time (sometimes reffered to as issuance time, cycle time, or initialization time).

projmins: Number of minutes from reference time to valid time.

desigreftime: Designated reference time; used as a common reference time for all items when individual reference times do not match.

desigprojmins: Number of minutes from designated reference time to valid time.

Query the nowCOAST LayerInfo web service, which has been created to provide additional information about each data layer in a service, including a list of all available "time stops" (i.e. "valid times"), individual timestamps, or the valid time of a layer's latest available data (i.e. "Product Time"). For more information about the LayerInfo web service, including examples of various types of requests, refer to the nowCOAST help documentation at: http://new.nowcoast.noaa.gov/help/#section=layerinfo

References Kithil, 2015: Overview of Lightning Detection Equipment, National Lightning Safety Institute, Louisville, CO. (Available from http://www.lightningsafety.com/nsli_ihm/detectors.html).NASA and NOAA, 2014: Geostationary Lightning Mapper (GLM). (Available at http://www.goes-r.gov/spacesegment/glm.html).NWS, 2013: Experimental Lightning Strike Density Product Description Document. NOAA/NWS/NCEP/Ocean Prediction Center, College Park, MD (Available at http://www.opc.ncep.noaa.gov/lightning/lightning_pdd.php and http://products.weather.gov/PDD/Experimental%20Lightning%20Strike%20Density%20Product%2020130913.pdf). ,li>NOAA Knows Lightning. NWS, Silver Spring, MD (Available at http://www.lightningsafety.noaa.gov/resources/lightning3_050714.pdf).) Siebers, A., 2013: Soliciting Comments until June 3, 2014 on an Experimental Lightning Strike Density product (Offshore Waters). Public Information Notice, NOAA/NWS Headquarters, Washington, DC (Available at http://www.nws.noaa.gov/om/notification/pns13lightning_strike_density.htm).

• Update Frequency: Weekly

Data from this dataset can be downloaded/accessed through this dataset page and Kaggle's API.

Context

Severe weather is defined as a destructive storm or weather. It is usually applied to local, intense, often damaging storms such as thunderstorms, hail storms, and tornadoes, but it can also describe more widespread events such as tropical systems, blizzards, nor'easters, and derechos.

The Severe Weather Data Inventory (SWDI) is an integrated database of severe weather records for the United States. The records in SWDI come from a variety of sources in the NCDC archive. SWDI provides the ability to search through all of these data to find records covering a particular time period and geographic region, and to download the results of your search in a variety of formats. The formats currently supported are Shapefile (for GIS), KMZ (for Google Earth), CSV (comma-separated), and XML.

Content

The current data layers in SWDI are:
- Filtered Storm Cells (Max Reflectivity >= 45 dBZ) from NEXRAD (Level-III Storm Structure Product)
- All Storm Cells from NEXRAD (Level-III Storm Structure Product)
- Filtered Hail Signatures (Max Size > 0 and Probability = 100%) from NEXRAD (Level-III Hail Product)
- All Hail Signatures from NEXRAD (Level-III Hail Product)
- Mesocyclone Signatures from NEXRAD (Level-III Meso Product)
- Digital Mesocyclone Detection Algorithm from NEXRAD (Level-III MDA Product)
- Tornado Signatures from NEXRAD (Level-III TVS Product)
- Preliminary Local Storm Reports from the NOAA National Weather Service
- Lightning Strikes from Vaisala NLDN

Disclaimer:
SWDI provides a uniform way to access data from a variety of sources, but it does not provide any additional quality control beyond the processing which took place when the data were archived. The data sources in SWDI will not provide complete severe weather coverage of a geographic region or time period, due to a number of factors (eg, reports for a location or time period not provided to NOAA). The absence of SWDI data for a particular location and time should not be interpreted as an indication that no severe weather occurred at that time and location. Furthermore, much of the data in SWDI is automatically derived from radar data and represents probable conditions for an event, rather than a confirmed occurrence.

Acknowledgements

Dataset Source: NOAA. This dataset is publicly available for anyone to use under the following terms provided by the Dataset Source — http://www.data.gov/privacy-policy#data_policy — and is provided "AS IS" without any warranty, express or implied, from Google. Google disclaims all liability for any damages, direct or indirect, resulting from the use of the dataset.

Cover photo by NASA on Unsplash
Unsplash Images are distributed under a unique Unsplash License.

The data consists of cloud-to-ground lightning strikes recorded by Vaisala's National Lightning Detection Network (NLDN) and aggregated into 0.1° latitude by 0.1° longitude tiles by the National Centers for Environmental Information. This means that all daily strikes within each 0.1° x 0.1° area are summed and assigned to the geographic coordinates representing the center of that area.

It's important to note that because the length of a degree of latitude decreases as you move away from the equator, the area covered by each tile becomes smaller the farther north you go. For instance, tiles at 50°N measure roughly 7 km by 11 km, while those at 20°N are about 10 km by 11 km—making the southern tiles nearly 43% larger in area.

For more information, you can see the https://ghrc.nsstc.nasa.gov/uso/ds_docs/nldn/gai_dataset.html#

This dataset contains 5 minute resolution lightning strike data for Central America.

This data set contains the cloud-to-ground and in-cloud lightning data from the National Lightning Detection Network (NLDN).

Lightning stroke data from the National Lightning Detection Network (NLDN) for the IMPACTS 2023 campaign.

This dataset contains the daily number of lightning strikes in 20km grid boxes collected throughout Alaska as part of the AK NSF EPSCoR Fire and Ice program.The dataset is is part of a historical study to evaluate the predictability of lightning in Alaska. These data were derived from the historical lightning strikes recorded by Alaska Lightning Detection Database (ALDN) for 1986 - 2017. The data were gridded to 20km for ease of comparison with existing downscaled climate data by counting the number of lightning flashes that occurred in each grid box. The 2012-2017 are only available in the form of the individual flashes while the number of flashes in each strike were estimated for 1986-2011 based on the observed multiplicity parameter. Purpose The data were prepared to improve forecasts of lightning in Alaska. These forecasts have historically focused on short-term weather at the National Weather Service but the data are being explored for subseasonal to seasonal forecasting applications. Lineage Observed cloud-to-ground lightning strike data were obtained from the Alaska Lightning Detection Network (ALDN) for 1986–2015 (1987 and 1989 are missing data). The ALDN data consist of the location, date, and time of each lightning strike determined by a network of magnetic-direction-finding stations. The number of lightning strikes over land were counted within each 20-km grid box. The count of strikes was produced at a daily scale. The lightning data were homogenized (the sensor network has been changed over time) by exploiting the strike multiplicity information that was included in the pre-2012 data, which provides an estimate of the number of strokes that occurred within each flash of lightning. The multiplicity parameter (i.e., the number of strokes) was summed for the pre-2012 data instead of counting each flash that occurred in each 20-km grid box. This simple approach provides an estimated number of lightning strokes each year over the 1986–2011 period that is more in line with how lightning was observed during the 2012–15 period in the interior.

The NAMMA ATD Lightning data provided by the UK Meterological Office from multiple outstations contains lightning stroke data, latitude and longitude, accuracy and weighting for fading-in flashes of lightning for the African Coast during the NAMMA experiment. Time is determined by the Arrival Time Difference (ATD) of the reporting stations. These data files were generated during support of the NASA African Monsoon Multidisciplinary Analyses (NAMMA) campaign, a field research investigation sponsored by the Science Mission Directorate of the National Aeronautics and Space Administration (NASA). This mission was based in the Cape Verde Islands, 350 miles off the coast of Senegal in west Africa. Commencing 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.

This data collection consists of archived Geostationary Operational Environmental Satellite-R (GOES-R) Series Geostationary Lightning Mapper (GLM) Level 0 data from the GOES-East and GOES-West satellites in the operational (OPS) and the post-launch test (PLT) phases. The GOES-R Series provides continuity of the GOES mission through 2035 and improvements in geostationary satellite observational data. GOES-16, the first GOES-R satellite, began operating as GOES-East on December 18, 2017. GOES-17 began operating as GOES-West on February 12, 2019. GOES-T launched on March 1, 2022, and was renamed to GOES-18 on March 14, 2022. GOES-U, the final satellite in the series, is scheduled to launch in 2024. GLM is a near-infrared optical transient detector observing the Western Hemisphere. The GLM Level 0 data are composed of Consultative Committee for Space Data Systems (CCSDS) packets containing the science, housekeeping, engineering, and diagnostic telemetry data downlinked from the instrument. The Level 0 data files also contain orbit and attitude/angular rate packets generated by the GOES spacecraft. Each CCSDS packet contains a unique Application Process Identifier (APID) in the primary header that identifies the specific type of packet, and is used to support interpretation of its contents. Users may refer to the GOES-R Series Product Definition and Users’ Guide (PUG) Volume 1 (Main) and Volume 2 (Level 0 Products) for Level 0 data documentation. Related instrument calibration data and Level 1b processing information are archived and available for order at the NOAA CLASS website. The GLM Level 0 data files are delivered in a netCDF-4 file format, however, the constituent CCSDS packets are stored in a byte array making the data opaque for standard netCDF reader applications. The GLM Level 0 data files are packaged in hourly tar files (data bundles) by satellite for the archive. Recently ingested archive tar files are available for 14 days on an anonymous FTP server for users to download. Data archived on offline tape may be requested from NCEI.

This data set is restricted to EOS affiliated researchers. The U.S. National Lightning Detection Network is a commercial lightning detection network operated by Global Atmospherics, Inc., (GAI), formerly Geomet Data Services. A network of about 105 antennae are connected to a central processor that records the time, polarity, signal strength, and number of strokes of each cloud-to-ground lightning flash detected over the United States starting from Jan. 1, 1994 to present.

The Global Hydrology Resource Center generates a cloud-to-ground lightning product from the data collected from the U.S. National Lightning Detection Network, a commercial lightning detection network operated by Global Atmospherics, Inc. (GAI), formerly Geomet Data Services. The daily products are produced by binning the number of flashes occurring in each pixel (pixel is approximately 8 km by 8 km) during a 24 hr period (00 UTC to 00 UTC). The data set begins on July 8, 1994 and continues through the present.

The Severe Weather Data Inventory (SWDI) is an integrated database of severe weather records for the United States. SWDI enables a user to search through a variety of source data sets in the NCDC (now NCEI) archive in order to find records covering a particular time period and geographic region, and then to download the results of the search in a variety of formats. The formats currently supported are Shapefile (for GIS), KMZ (for Google Earth), CSV (comma-separated), and XML. The current data layers in SWDI are: Storm Cells from NEXRAD (Level-III Storm Structure Product); Hail Signatures from NEXRAD (Level-III Hail Product); Mesocyclone Signatures from NEXRAD (Level-III Meso Product); Digital Mesocyclone Detection Algorithm from NEXRAD (Level-III MDA Product); Tornado Signature from NEXRAD (Level-III TVS Product); Preliminary Local Storm Reports from the NOAA National Weather Service; Lightning Strikes from Vaisala NLDN.

These data come from the lightning sensor on the barge. The sensor reports every lightning strike within a 300 mile (480km) radius and distinguishes CG-IC strikes and strike polarity. This dataset has been quality controlled.

The Geostationary Lightning Mapper Level 2 Lightning Detection product contains a list of lightning flashes, and their constituent groups and events. The definition of and relationship among flashes, groups, and events are governed by the following spatial and temporal characteristics: An event represents the signal detected from the cloud top associated with a lightning emission in an individual sensor pixel for a 2ms integration period; A group represents the events detected in adjacent sensor pixels for the same integration period as an event; A flash represents a series of measurements constrained by temporal and spatial extent thresholds that are associated with one or more groups. The parent, child relationship among specific flashes, groups, and events is stored in the product. Data for each flash includes an energy-weighted centroid latitude, longitude _location, time span of occurrence, amount of radiant energy, and coverage area. Data for each group includes an energy-weighted centroid latitude, longitude _location, mean time of occurrence, amount of radiant energy, and coverage area. Data for each event includes a latitude, longitude _location, time of occurrence, and amount of radiant energy. The product includes data quality information for each flash and group. A Lightning Detection product file contains a set of flashes, and its constituent groups and events for a 20 second period. The units of measure for the flash, group, and event radiant energy values is Joules. The units of measure for the flash and group coverage areas is square meters.

The NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) combines detailed, flash-specific measurements of lightning with both theoretical and empirical laboratory results to obtain estimates of lightning NOx production. Each LNOM dataset is based on measurements from a specific regional VHF Lightning Mapping Array (LMA), and on ground flash location, peak current, and stroke multiplicity data from the National Lightning Detection Network (NLDN). Both the LMA and NLDN data are used to determine the flash type (ground or cloud) of each flash occurring within an analysis cylinder. The LNOM analyzes the LMA sources to estimate the total channel length of each flash. It also produces the Segment Altitude Distribution (SAD) product by dicing up the lightning channel into 10-m segments, and then tallies those segments as a function of altitude. From all of the 10-m segments, the LNOM computes the vertical lightning NOx profile inside the analysis cylinder and the total NOx produced by each flash. A summation of the NOx profiles contributed to the analysis cylinder by each flash gives the final lightning NOx profile product for the analysis period studied (typically a 1 month profile). The LNOM NOx profiles include NOx from several non-return stroke lightning NOx production mechanisms. Users of LNOM data typically include regional air quality and global chemistry/climate modelers who need to better-parameterize lightning NOx sources. Rather than assigning an unrealistic fixed amount of NOx to ground and cloud flashes, the modeler can employ LNOM data to assign realistic (and statistical) NOx profiles to each flash.