Lightning Climatology Oklahoma Lightning Mapping Array May September

Lightning Climatology Oklahoma Lightning Mapping Array May - September, 2004 - 2005 Paul Krehbiel New Mexico Tech September 28, 2005

Lightning Mapping Arrays (LMAs) ● Utilize time-of-arrival technique ● Consist of 10 -12 stations over 50 -70 km diameter area ● Passive system: locates impulsive radio frequency signals produced by lightning (radio 'static') ● Listens in a locally unused VHF TV channel (e. g. , Ch 3, 5, 8) ● Produce observations in near real-time (1 -2 minute delay) ● Provide good spatial accuracy and temporal resolution Existing systems: ● New Mexico Tech LMAs: Northern Alabama (NASA/Huntsville), Oklahoma (OU/NSSL), Langmuir Laboratory (NMT), WSMR, . . . ● Vaisala (formerly GAI) LDAR II: Dallas/Ft. Worth, Houston (TAMU), Kennedy Space Center.

Oklahoma LMA data: Real time observations: • Cover a large area (400 -500 km diameter) • 3 D over 200 -300 km diameter area • Data are simultaneous; short update times (2 min) Useful information: • Plan source densities (vertically integrated) • Altitude vs. time source density plots Lightning activity shows where strong convection is occurring, and if intensifying or weakening (See lightning. nmt. edu)

Zoomed-in example: Density of Points Display Moore, OK tornadic storm May 10, 2003 10 min of observations (NLDN events in green) -> xlma analysis software Texas

Climatology Data from Oklahoma LMA The following slides show on a month-by-month basis the number of located LMA sources as a function of the day of the month and the hour of each day, in the form of a 3 -dimensional bar graph (generated using the ‘bar 3’ plotting tool of Matlab). The vertical bars indicate the number of sources per hour on a logarithmic scale to prevent large mesoscale systems from dominating the plots. The units are kilosources/hour, with a threshold value of 1000 sources/hour being applied to discriminate against weakly-detected, distant storms from cluttering up the presentation (any storm of reasonable size and within range of the LMA will produce several thousand sources/hour). To determine what the storms look like during an active period, see http: //lightning. nmt. edu/oklma. (Bar graphs are shown only for April through September but are available for the entire year. )

Number of located LMA sources, April 2004, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, April 2005, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, May 2004, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, May 2005, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, June 2004, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, June 2005, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, July 2004, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, July 2005, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, Aug. 2004, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, Aug. 2005, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, Sept. 2004, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

Number of located LMA sources, Sept. 2005, Oklahoma (Daylight ~12 -24 UTC; 7 am – 7 pm CDT)

For real-time data plots, archived daily and hourly, see http: //lightning. nmt. edu/oklma

Lightning Climatology STEPS 2000 Lightning Mapping Array (NW Kansas, E Colorado, SW Nebraska) May 24 – August 10, 2000

Two supercell storms in NW Kansas–SW Nebraska - June 7, STEPS 2000 -13 station LMA network - Close storm: Low Precip - Far storm: High Precip - 10 min time interval - ~Continuous IC lightning - Inverted polarity storms (deep mid-level + charge - Only one NLDN event - negative CG (real? ) - Major advantage of total lightning vs. CG only Note: Major Ch 3 TV interference data processed with autothresholding.

Aircraft track and storms, May 25, STEPS 2000 (Aircraft being charged while flying through downwind cirrus/anvil cloud)

Example of Highly Dendritic Negative CG flash Height vs Time Height vs E-W Plan View Height vs N-S

Number of located LMA sources, May 2000, STEPS (Daylight ~12 -02 UTC; 6 am – 8 pm MDT)

Number of located LMA sources, June 2000, STEPS (Daylight ~12 -02 UTC; 6 am – 8 pm MDT)

Number of located LMA sources, July 2000, STEPS (Daylight ~12 -02 UTC; 6 am – 8 pm MDT)

Number of located LMA sources, August 2000, STEPS (Daylight ~12 -02 UTC; 6 am – 8 pm MDT)

(The End)

Time-of-Arrival Concept: impulsive lightning event at (x, y, z; t) z x y

Oklahoma Lightning Mapping Array 11 station network, 50 km diameter Real-time processing & display University of Oklahoma/National Severe Storms Laboratory

Oklahoma LMA Station

North Alabama Lightning Mapping Array (NASA) Map (10 stations) http: //branch. nsstc. nasa. gov/ One hour of real-time data

New Mexico LMA Networks

Portable LMA System (Vortex II, DC Network, DC 3? ) • Electronics housed in shielded thermoelectric cooler enclosure • Operate from external 12 VDC battery and/or power supply. ~12 (+48) watts power • Battery operation: 48+ hours (w/out cooling) 20+ hours (with cooling) • Lightweight (10 lbs) • ¼ wave ground plane antenna (Ch. 8 shown; 180 -186 MHz) • Connected to receiver in box by coaxial cable • Other external connectors: GPS antenna, ethernet, 12 VDC