UPLIGHTS – Second Season Observations

The second summer of observations for the UPLIGHTS campaign took place from May – Aug 2013.  Unlike the previous year where drought conditions limited the total number of storms, this year saw a dramatic increase in the number of thunderstorms and upward flashes.

The second observation season of UPLIGHTS took place from 27 May 2013 – 15 Aug 2013.  There were a total of 81 operations days with assets deploying on 33 days (41%).  High-speed camera captures were made on 19 days (23%).  There were 20 down days (25%) in which weather conditions precluded any chance of observations.

During the 19 days when high-speed captures were made, there were a total of 134 flashes observed encompassing 262 individual high-speed captures.  A breakdown of captured flash types is given in Table 1 below.  Unlike the previous season, in which there were only 2 upward flashes observed, there were 15 upward flashes observed during the operations timeframe.  The storms associated with the 15 upward flashes occurred on 5 different days: 30 May, 23 Jun, 8 Jul, 25 Jul and 5 Aug 2013.

From 21 May to 9 Jun, the ZT Research observation truck along with two high-speed cameras deployed near Salina, Kansas to capture upward flashes from wind turbines near a Lightning Mapping Array.  54 flashes were captured during this time, one of which was an upward flash.

There were two additional days when upward flashes occurred outside of the operations timeframe.  On 9 Sep 2013 there were 8 upward flashes when a well-organized MCS and trailing stratiform precipitation region passed over Rapid City.  These upward flashes were observed with autonomously operating standard-speed video cameras and digital still cameras along with an electric field meter.  On 4 Oct 2013, an intense blizzard impacted the western South Dakota region.  During heavy snow in Rapid City, it appears there were 25 self-initiated upward flashes from the towers.  5 of these upward flashes were recorded by interferometer system before it lost power.  An electric field meter located 5 km west of the towers recorded data for the entire storm.

Table 1. Flashes captured with high-speed cameras

UP

+CG

-CG

IC

Total

15

56

50

28

134*

UP = upward flash

+CG = positive cloud-to-ground flash

-CG = negative cloud-to-ground flash

IC = cloud flash

*The total reflects the sum of CG and IC flashes.  The 15 upward flashes occurred during either a CG or IC flash.

Total upward flashes from 2013 being evaluated and analyzed by UT date:

  • 30 May: 1
  • 23 Jun: 5
  • 8 Jul: 2
  • 25 Jul: 4
  • 5 Aug: 2
  • 9 Sep: 8
  • 4 Oct: 5 recorded by the interferometer system (25 total)
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