The UPward LIGHtning Triggering Study (UPLIGHTS) took place from 1 Sep 2011 – 31 Aug 2014. There were three summer thunderstorm seasons in which formal observations were made. These timeframes were
16 May – 24 Aug 2012
27 May – 15 Aug 2013
30 May – 31 Aug 2014
There were a total of 276 operations days with assets deploying on 85 days (31%). High-speed camera captures were made on 58 days (21%). There were 100 down days (36%) in which weather conditions precluded any chance of observations.
During the 58 days when high-speed captures were made, there were a total of 705 flashes observed encompassing 1,237 individual high-speed captures. A breakdown of flashes captured with high-speed cameras is given below.
There were a total of 67 upward flashes observed during the UPLIGHTS campaign (i.e., 1 Sep 2011 – 31 Aug 2014), however, only 34 occurred during the formal observation timeframes. 31 of the 34 upward flashes were captured by high-speed cameras. There were two days in which upward flashes occurred outside of these observation periods. On 9 Sep 2013 a linear MCS with well-defined trailing stratiform precipitation area produced 8 upward flashes. Although there were no high-speed cameras or INPE fast antenna sensors operating, autonomous standard-speed video cameras, digital still cameras and electric field meters recorded the flashes. 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. A single electric field meter located 5 km west of the towers recorded data for the entire storm. Therefore, there were an additional 33 upward flashes recorded outside of the observation timeframes by some of the autonomously operating UPLIGHTS assets. Considering only those upward flashes occurring at one or more of the towers in Rapid City, there were 63 upward flashes 38 of which occurred during summertime thunderstorms.
|Rapid City towers, summer storm (13 storms)||38|
|Rapid City towers, winter storm (single blizzard)||25|
Flashes captured with high-speed cameras
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 31 upward flashes occurred during either a CG or IC flash.