A Statistical Test of Station Thunderstorm Days Based on Lightning Location System and Its Evolution Characteristics

Abstract

To research the continuity and climate evolution characters of station lightning data in Fujian Province， the paper established the calculation model based on Lightning Location System.The data sorted to thunderstorm days by observed（1982 -2013） and by Lighting Location System（2011 -2020） were used respectively.The paper determined the monitoring radius of lightning Location System that best matches the manual observation Combined with the T test and F test results.On this basis， the maximum penalty F test （PMFT）method was used to test the continuity of thunderstorm daily data from 66 stations in Fujian Province， and the passing rate under different monitoring radius and the mean square error of observation and monitoring were compared to obtain the optimal matching monitoring radius of Lightning Location System.Empirical Orthogonal Function （EOF） and 9-point smoothing coefficients were used to analyze the spatial and temporal evolution characteristics in Fujian Province during 1982 -2021 under the optimal matching radius and the factors influencing the activity pattern of thunderstorm days.The results show that： （1） The optimal matching radius between Lightning Location System is 12 km， and the passing rate （failed rate） of the （PMFT） test of 66 stations in the province is 80.30% （19.70%）； （2） The spatial pattern of thunderstorm days in Fujian Province during 1982 -2021 is uneven， which are characterized that thunderstorm activity is stronger in the southwest then east coast， The spatial patterns of the three modes of EOF mainly include "province-wide Province- wide negative phase"， "northeast- southwest Province-wide negative phase"， and "inland coastal Province-wide negative phase".The first mode variance contribution rate is 55%， which can be the major mode， its 9-point smoothed curves and time coefficients characterize the Midwest and South have more lightning activity before 1998 and after 2016， and less lightning activity during 1998 -2016； （3） ENSO has a certain influence on the thunderstorm activity pattern in Fujian Province， and the correlation coefficients of ENSO， El Niño， La Niña and thunderstorm days in Fujian Province are 43.80%， 55.22% and 14.21% respectively.In summary， the 12 km radius can be used as an effective forecast basis and the optimal matching monitoring radius between manual observation and Lightning Location System leading to solve the problem of continuity of lightning data in Fujian Province.It is important to study the law of lightning activity for improving the ability of lightning disaster prevention.By comparing several kinds of climate events， El Nino has a great influence on the thunderstorm activity pattern in Fujian Province， which is considered as one of the important factors affecting the lightning activity pattern in Fujian Province.

Keywords

• thunderstorm days
• optimal matching radius
• t test
• t test
• t test