STEPS 2000 JD 00156 04JUN2000
PRELIMINARY SPRITE LOG
The following is a very preliminary listing of the times of sprites imaged at the Yucca Ridge Field Station. These are based solely on real-time visual inspection of the video monitoring system. There are most likely some additional sprites not listed and not all those below may in fact be sprites. All times are UTC. Times are likely to be within ±5 seconds of actual time.
SUMMARY: Full Operations. Long range viewing. Employed ITT GEN III unit for first time with great success. Few small cells moved off mountains in afternoon but no real convection developed anywhere along Front Range. However, several systems in Midwest allowed for longer range viewing. An MCS in eastern NE and Iowa grew to rather large size towards midnight. Though viewing was near optimal, we never say any TLEs form this system. It did have relatively low flash rates, and it is possible that thin smoke limited viewing at sub 3 degree elevations at these longer ranges (700+ km). A more intense MCS in SD moved southeast. It began producing elves around 0539 Z. There were about a dozen "elves" in as many minutes. Several were very large, but many were very small, thin disks which tended to form in the same place. They appeared clearly in the ITT GEN III system, and the red and blue Xybions, as well as the Stanford camera. The TLEs were associated with very sharp, crisp loud VLF bursts. Definitely not sprite-like VLF. Not sure if any sprites were seen from this system, which had relatively modest stratiform region, and many intense convective cores (>65 dBZ). The events lasted for about two hours. Then a new cell formed almost in the field of view at about 400 km range, producing many cloud flashes. This cell had low CG rates, but a high percent of positive. It had multiple cores and reached 71 dBZ, most likely a hailer. Cloud flashes greater than 1 per second, but as storm developed and moved southeast, never saw any evidence of a TLE. Classic null case (though this storm may have produced TLEs after shut down). While originally on the northeast fringe of the LMA, the storm was out of LMA range so a decision was made to terminate. Thunderstorm watches issued for SD, ern NE, MN and IA storms, but not central NE storms. Mounting ring on GEN III did not fit quite right, causing some blurring of image.
Shot Red XYBION patrol and Blue Xybion Zoom along with GEN III (4 Sony tapes plus two hours on S-VHS with GPS timing). Perhaps some residual smoke in area, though sky was unusually clear, but lacked a little crispness. Moon not a factor. Very few clouds in FOV.
Total TLEs from Yucca Ridge This Campaign: 190
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(S) = Sprite; (E) = Elve; (B) = Blue Jet; (CF/CG) = Cloud/Ground flash; (M)=Meteor
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JD 00156 – 4 JUN 2000
0342Z. Start LLTV Observations
0750Z. End LLTV Observations
O425.15 [E?]
0539.13 [E]
0539.40 [E?]
0540.05 [E,S?]
0541.52 [E?]
0542.24 [E]
0544.55 [E?]
0545.38 [E?]
0545.55 [E]
0546.10 [E]
0547.15 [E]
0549.24 [E]
0549.34 [E]
0551.42 [E?]
0609.16 [E]
0612.25 [E-]
0614.34 [E]
0615.08 [E]
0616.35 [E-]
0617.50 [E]
0623.47 [E]
0624.01 [E]
0624.34 [E]
0625.56 [E]
0627.17 [E?]
0628.00 [E+]
0631.07 [E?]
0643.02 [E?]
0730.25 [?]