Short-term Prediction Research
and Transition Center

Meetings - Abstract

Lightning Detection and Ranging (LDAR) II is Vaisala’s research-grade system that resulted from a NASA Kennedy Space Center technology transfer project. Like LDAR and New Mexico Tech’s LMA system, this system employs 3-Dimensional Time-of-Arrival location methods to map VHF emissions from cloud (CLD) and cloud-to-ground (CG) lightning (Total Lightning). CG return strokes are not detected or located by this detection technology.

This presentation provides a technical overview of the LDAR II research sensors and the associated central processing systems. Elements of the design that facilitate ease-of-use, reliability, and “communications rate vs. performance” trade-offs are also presented. Performance modeling (locations accuracy and detection efficiency) is briefly discussed, and the resulting estimated performance for our Dallas Fort Worth (DFW) LDAR II network is presented. Some samples of flash-level and storm-level data from the DFW network are included.

LDAR provides a tremendous about of information about the nature and 3-dimensional extent of lightning. However, it also requires many sensors to reliably locate a discharge -- each of which must operate at a very high communications rate. An alternative way to obtain 2- and 3-dimensional Total Lightning information at VHF is to employ interferometry. This technology can locate events with as few as two sensors, and can operate at much lower communications rates than LDAR II. However, fewer sources per flash are typically located by interferometry, and the location accuracy for these sources is not as good as LDAR II. This presentation includes a brief discussion of Vaisala’s SAFIR interferometry systems and data, including a new 3-dimensional (solid angle) interferometer. A 3-dimensional interferometric network is currently being installed in the DFW area, and will be compared with the LDAR II system. We eventually plan to use this system to produce Total Lightning products for the LATEST evaluations to be carried out by the DFW NWS office.