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Figure 15. Ambient electric field meter recordings for an upward flash with an UNL. The red trace is from the West Sensor site EFM, the black trace is from the North Sensor site EFM, and the blue trace is from the South Sensor site EFM.

Edens, H. E., K. B. Eack, E. M. Eastvedt, J. J. Trueblood, W. P. Winn, P. R. Krehbiel, G. D. Aulich, S. J. Hunyady, W. C. Murray, W. Rison, S. A. Behnke, and R. J. Thomas (2012), VHF lightning mapping observations of a triggered lightning flash, Geophys. Res. Lett., 39, L19807, doi:10.1029/2012GL053666.

###### ACKNOWLEDGMENT

Jiang, R., X. Qie, Z. Wu, D. Wang, M. Liu, G. Lu and D. Liu (2014), Characteristics of upward lightning from a 325-m-tall meteorology tower, J. Atmos. Res., 149, pp. 111-119, doi:10.1016/j.amtosres.2014.06.007

This research was made possible through National Science Foundation (NSF) grant AGS-1048103 and through FAPESP grants 2012/15375-7 and 2013/05784-0. Additionally, NSF grant ATM – 0813672 provided funding for concurrent high- speed optical spectra observations during UPLIGHTS. We would like to thank Dr. Walt Lyons for his help with forecasting and insight and expertise into the development of horizontally extensive flashes. We would also like to acknowledge Chip Redmond, John Hamilton, Jeferson Alves and Dan McKemy for their participation in the collection of data during UPLIGHTS. A special thank you to Mike Bickett for his many contributions in the fabrication, installation and maintenance of equipment and housings used during UPLIGHTS and to Seth White, Eddie and Marty Rypkema, Pete Lein, Kim Kjerstad, Rick MacDonald, Bill Kopp, Travis Madsen, Quiten Feickert, Dan Holsworth and Jim Bickett for the use of their land for sensors and observations. The data collected during UPLIGHTS is maintained by and available upon request from Tom A. Warner, tom.warner@ztresearch.com. A duplicate copy of this data is maintained by Marcelo Saba, Ph.D., marcelo.saba@inpe.br and Carina Schumann, Ph.D., carina.schumann@gmail.com.

Krehbiel, P. R.., R. J. Thomas, W. Rison, T. Hamlin, J. Harlin and M. Davis (2000), GPS-based mapping system reveals lightning inside storms, Eos, Trans. Am. Geophys. Union, 81, 21.

Lu, G., S. A. Cummer, J. Li, F. Han, R. J. Blakeslee, and H. J. Christian (2009), Charge transfer and in-cloud structure of large-charge-moment positive lightning strokes in a mesoscale convective system, Geophys. Res. Lett., 36, L15805, doi:10.1029/2009GL038880.

Lyons, W. A., S. A. Cummer, S. A. Rutledge, T. J. Lang, T. Meyer, T. A. Warner, and T.A. Samaras (2011), TLEs and their parent lightning discharges, paper presented at 14th Intl. Conf. on Atmospheric Electricity, August 7-12, Rio De Janeiro, Brazil, 4 pp.

Lyons, W. A., T. A. Warner, S. A. Cummer, S. A. Rutledge, T. J. Lang, T. C. Meyer, G. Lu, T. E. Nelson, and T. Samaras (2012) Different strokes: Researching the unusual lightning discharges associated with sprites and jets and atypical meteorological regimes, paper presented at the 22nd Intl. Lightning Detection Conf., Broomfield, CO, Vaisala, Inc., www.vaisala.com/en/events/ildcilmc/ Pages/ILDC-2012-archive.aspx

Lyons, W. A., T.E. Nelson, T.A. Warner, T.J. Lang, K. Cummins, M. Quick, W. Rison, P. Krehbiel, S.A. Cummer, J. Myers, T. Samaras, P. Samaras, C. Young (2014), Meteorological Aspects of Two Modes of Lightning Triggered Upward Lightning (LTUL) Events in Sprite-Producing MCSs , paper presented at the 23nd International Lightning Detection Conference, Mar 18 - 19, Tucson, Arizona.

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