Vaisala Long Range Lightning Detection Network
These data are restricted to collaborators that have a working relationship with the NASA Marshall Space Flight Center (MSFC) Lightning Group.
Introduction
This dataset consists of lightning data produced by a Long Range Lightning Detection Network operated by the Vaisala Group. The Vaisala website is located at LightningStorm.com and should be contacted by non-NASA affiliated researchers for obtaining lightning data.
The network is comprised of the U.S. National Lightning Detection Network (NLDN) and the Canadian Lightning Detection Network (CLDN), the latter commissioned for operations in February 1999. These two networks comprise an integrated North American Lightning Detection Network (NALDN) consisting of 187 sensors. The sensors 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 Gulf of Mexico, the Atlantic, and the Pacific Oceans. A combination of time of arrival and direction finding technology is used to locate each flash. The NLDN uses 47 Advanced Lightning Direction Finders (ALDFs) in combination with 59 LPATS III electric field sensors. The CLDN uses 26 IMPACT/ES sensors and 55 LPATS-IV sensors. Depending on the location within the network, Vaisala claims a location accuracy of 500 meters, with a detection probability between 80-90 percent, varying by region. These data are ingested in near real-time and stored in a raw data file.
File Format for Raw Data
Raw Long Range Lightning data is saved as ASCII text files as shown in the sample data line below. Each field of data is separated by a space. Below the example data line appears a table showing each field and its associated function.
This dataset starts April 22, 2003, and has a format that looks like the example below, which continues until Feburary 7, 2007:
Sample data line:
02/06/07 00:00:14 31.440 -178.423 2.0
| Column Number |
Field name |
Example |
1 |
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2 |
Time of strike (to seconds)
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3 |
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4 |
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5 |
Semimajor Axis in Kilometers, of 50% probability ellipse for each flash
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On Feburary 7, 2003, this dataset had a change in the way the date was shown for each lightning strike. The data continued like this until the version 2 data started on June 10, 2007. (The column layout was un-changed) See data sample below.
Sample data line:
2007-02-07 18:32:15 36.325 -65.727 2.4
On June 10 2007, we started ingesting and archiving the data in the extended format as shown below. At this time the daily files include a "v2" in the filenames.
Sample data line:
06/27/07 16:18:21.898 18.739 -88.184 0.0 kA 0 1.0 0.4 2.5 8 1.2 13
On April 3 2008, we started ingesting the stroke data, with an additional field added for " Cloud-to-Ground / In-Cloud Discriminator (0=CG, 1=IC)". This is field number 13 in the chart below. The version number of these data have changed to "v3" in the filenames.
Sample data line:
04/04/08 10:19:21.223 17.539 -84.283 0.4 kA 0 1.0 0.4 2.3 8 1.1 12 0
On may 21, 2008, the Cloud-to-Ground / In-Cloud Discriminator (field 13) was again changed. This field is now either a "G" or a "C", for Cloud-to-Ground or Cloud-to-Cloud, respectively.
Sample data line:
05/22/08 10:15:21.243 17.529 -84.283 0.4 kA 0 1.0 0.4 2.3 8 1.1 12 G
Version 2 and version 3 data are discribed in the chart below, with version 2 having only the first 12 column entries.
| Column Number |
Field name |
Example |
1 |
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2 |
Time of strike (UTC; to milliseconds)
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3 |
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4 |
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5 |
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6 |
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7 |
Semi-major Axis in Kilometers, of 50% probability ellipse for each flash
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8 |
Semi-minor Axis in Kilometers,of 50% probability ellipse for each flash
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9 |
Ratio, Semi-major to Semi-mminor Axis
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2.5
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10 |
Angle of 50% probability ellipse from North (Angle of Orientation )
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11 |
Chi-squared value of statistical calculation
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12 |
Number of sensors reporting the flash
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13 |
Cloud-to-Ground / In-Cloud Discriminator (0=CG, 1=IC) or (G,C) |
(0,1) or (G,C) |
File Naming Convention
A raw data file is produced for each day of the year. The naming convention for the Vaisala Long Range Detection Network raw data file is:
VLrflashyyyy.ddd_daily_lit.raw, or
VLrflashyyyy.ddd_daily_v?_lit.raw
where yyyy is the year and ddd is the day of year, and v? is the version number. Version 2 is the extended version started on June 10, 2007, and version 3 is the version started on April 3, 2008.
Citing Lightning Data
Our data sets are provided through the NASA Earth Science Data and Information System (ESDIS) Project and the Global Hydrology Resource Center (GHRC) Distributed Active Archive Center (DAAC). GHRC DAAC is one of NASA's Earth Observing System Data and Information System (EOSDIS) data centers that are part of the ESDIS project. ESDIS data are not copyrighted; however, in the event that you publish our data or results derived by using our data, we request that you include an acknowledgment within the text of the article and a citation on your reference list. Examples for general acknowledgments, data set citation in a reference listing, and crediting online web images and information can be found at: http://ghrc.nsstc.nasa.gov/uso/citation.html
References
Cummins, K. L., R. B. Pyle, and G. Fournier, 1999. An Integrated North American Lightning Detection Network, Proceedings of the 11th International Conference on Atmospheric Electricity, Guntersville, AL, June 7-11.
Cramer, J. A., and K. L. Cummins, 1999. Long-Range and Trans-Oceanic Lightning Detection, Proceedings of the 11th International Conference on Atmospheric Electricity, Guntersville, AL, June 7-11.
Cummins, K. L., M. J. Murphy, E. A. Bardo, W. L. Hiscox, R. B. Pyle, and A. E. Pifer, 1998. A Combined TOA/MDF Technology Upgrade of the U. S. National Lightning Detection Network, J. Geophys. Res., 103, 9035-9044.
Idone, V. P., D. A. Davis, P. K. Moore, Y. Wang, R. W. Henderson, M. Ries, and P. F. Jamason, 1998. Performance evaluation of the U. S. National Lightning Detection Network in eastern New York, 1, Detection Efficiency, J. Geophys. Res., 103, 9045-9056.
Contact Information
To order this data or for further information, please contact:
Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: support-ghrc@earthdata.nasa.gov
Web: http://ghrc.nsstc.nasa.gov/
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