Jurecka, Joseph William (2008-08). An evaluation of lightning flash characteristics using LDAR and NLDN networks with warm season southeast Texas thunderstorms. Master's Thesis. Thesis uri icon

abstract

  • A comparison of flash parameters from the National Lightning Detection Network (NLDN) is made with data obtained from the Houston Lightning Detection and Ranging II (LDAR) network. This research focuses on relating the peak current and number of strokes in a negative flash (multiplicity) of lightning with the spatial extent and mean altitude of three-dimensional lightning in 1407 flashes as mapped by the LDAR network. It is shown that increasing negative multiplicities over the range two through ten exhibit, on average, a higher flash extent with higher multiplicities. Singlestroke flashes have mean heights of nearly 2 km greater. Higher order multiplicities (2 to 10+) were correlated with mean source heights near 8 km. Increasing multiplicity tends to be associated with greater flash extents increasing more horizontally than vertically with a 50% to 70% increase in flash extent. No obvious relationship between peak current and flash extent was observed. Examining peak current and mean height shows that low current flashes (<10kA) exhibit higher mean heights. However, this may be due to intra-cloud only flashes being reported as cloud to ground events by the NLDN. Bipolar flashes do not show much variation with height and flash extent with the exception of negative-first bipolar flashes, which exhibited mean flash extents twice that of other types. Finally, the flash detection efficiency is 99.7% within 60 km of the network center.
  • A comparison of flash parameters from the National Lightning Detection
    Network (NLDN) is made with data obtained from the Houston Lightning Detection and
    Ranging II (LDAR) network. This research focuses on relating the peak current and
    number of strokes in a negative flash (multiplicity) of lightning with the spatial extent
    and mean altitude of three-dimensional lightning in 1407 flashes as mapped by the
    LDAR network. It is shown that increasing negative multiplicities over the range two
    through ten exhibit, on average, a higher flash extent with higher multiplicities. Singlestroke
    flashes have mean heights of nearly 2 km greater. Higher order multiplicities (2
    to 10+) were correlated with mean source heights near 8 km. Increasing multiplicity
    tends to be associated with greater flash extents increasing more horizontally than
    vertically with a 50% to 70% increase in flash extent. No obvious relationship between
    peak current and flash extent was observed. Examining peak current and mean height
    shows that low current flashes (<10kA) exhibit higher mean heights. However, this may
    be due to intra-cloud only flashes being reported as cloud to ground events by the
    NLDN. Bipolar flashes do not show much variation with height and flash extent with the exception of negative-first bipolar flashes, which exhibited mean flash extents twice
    that of other types. Finally, the flash detection efficiency is 99.7% within 60 km of the
    network center.

publication date

  • August 2008