On network performance and data quality of a lightning detection network in Korea (KLDN)

Abstract

The quality of lightning data and system performance of network are keys to improving timely launching at space facilities. The quality of lightning data that are obtained by Korea Meteorological Administration (KMA) lightning detection network (KLDN) is evaluated over the Korean Peninsula in climatological perspective. A new methodology is developed to evaluate the performance of KLDN. The spatial distributions of the ellipse area, chi-square, and peak current are analyzed for the purpose of quantifying the quality of data from KLDN. The performance of the KLDN is also evaluated with a normalized frequency distribution function (NFDF) of peak currents and the peak values of NFDF with ranges. The monthly and diurnal variations of lightning strokes are presented.Of the total number of lightning strokes, 74% occur in summer (June, July, and August). Diurnal variation shows a bimodal distribution with peaks at 0600LST and 1500LST. High stroke density is identified over two locations: the Yellow Sea and the western inland region of the Korean Peninsula. The mean value of the peak current is more than 12.5kA and the ellipse area is less than 20km2 in most of the inland regions. The spatial distributions of the mean peak current and the ellipse area show the effects of the topography and geometry of the lightning sensor network. Theoretical simulation with topography shows that the time-of-arrival (TOA) sensor uncertainty of the KLDN network is at least 0.4km so that significant delay of the propagation path due to topography is not detectable. The NFDF is derived from the distribution of the peak current as a function of detection ranges and then is fitted with a log-normal function. The peak of NFDF is derived as functions of ranges and the linear and quadratic fitting are applied. Peak Current=6×10−5×Range2+0.0040×Range+3.3456 with R2=0.9938. The slope of this function and the peak values of NFDF are bigger than those from the simulation, suggesting that better optimization of KLDN is required.