Extended Abstract (436K)P1B.4
Comparisons of LDAR network height and density data with WSR-88D echo top and SCIT reflectivity data
Nicholas W. S. Demetriades, Vaisala, Tucson, AZ; and R. L. Holle and M. J. Murphy
WSR-88D reflectivity data and the algorithms used to help meteorologists interpret these data are extremely important in nowcasting. However, a number of inherent problems arise when tracking thunderstorm cells with three-dimensional reflectivity. These problems include: (1) identifying and tracking cells in complex multi-cellular thunderstorm environments, (2) detecting thunderstorm cells at close range from the radar, (3) echo top altitude trends that exaggerate or misidentify thunderstorm growth and decay, and (4) volume scans that take 5 minutes to complete. Lightning Detection and Ranging (LDAR) provides another 3-dimensional thunderstorm dataset that has the potential to complement, and in some cases supplement, WSR-88D reflectivities. It detects the breakdown processes of lightning in three-dimensions with high time and spatial resolution.
Vaisala has compared thunderstorm cell identification, tracking and altitude trends from radar data processing algorithms with lightning data provided by LDAR. Lightning density plots were used for cell identification and aided in tracking lightning cell altitude trends. LDAR has been able to identify thunderstorm cells more accurately in some complex multi-cellular environments. Two major reasons are (1) LDAR’s higher spatial resolution relative to WSR-88D, and (2) maxima in lightning activity aloft appear to be closely associated with convective cores only. LDAR density data have also shown great continuity that tracks thunderstorm cells well. In a number of thunderstorms, altitude trends obtained from echo tops exhibited unrealistic growth and decay and were better represented by lightning altitudes. The exaggerated trends were partially due to echo tops from cells moving between different vertical tilts of the radar beam, and partly due to storms approaching the radar and gradually being caught in the cone of silence. The continuous data stream provided by LDAR allowed cells to be tracked with more rapid update cycles than the typical 5-minute update time of radar. In summary, such information complements radar by providing a higher level of detail in both time and space for thunderstorm growth and decay.
Poster Session 1B, MCS/Orographic Precipitation/Lightning Poster
Wednesday, 6 August 2003, 1:30 PM-3:30 PM
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