基于风云四号卫星LMI数据的黑龙江省闪电活动特征研究

Analysis of lightning activity characteristics based on LMI data of FY-4 satellite in Heilongjiang Province

FY-4A闪电成像仪(LMI)为亚太地区首次研制发射的同类载荷,可以实现对闪电活动的实时、连续监测和跟踪。利用2018—2021年6—9月LMI的闪电事件(Event)观测数据,分析了黑龙江省闪电密度和辐亮度变化特征,结果表明:黑龙江省闪电密度和平均辐亮度空间分布不均匀,闪电密度高值区主要分布在黑龙江省北部、中南部和西部;平均辐亮度高值区主要分布在黑龙江省北部、中部和东南部部分地区。黑龙江省东部和西部地区闪电密度和辐亮度呈反相关,西部闪电密度高但辐亮度较低,东部闪电密度低但辐亮度较高。闪电次数高发月份是6—7月,约占闪电事件总数的78.6%,闪电次数日变化呈现“双峰”,凌晨3时和傍晚16时为峰值时刻。闪电平均辐亮度随月份呈线性降低,且辐亮度月分布呈右偏态,日变化呈现“单峰”,峰值为中午12时左右。2018—2021年闪电事件辐亮度分布为偏态单峰型,0~20μJ/m^(2)/ster范围是高频率区间。

The FY-4A Lightning Imager(LMI)is the first of its kind developed and launched in the Asia-pacific region.It can realize real-time and continuous monitoring and tracking of lightning activity.In this paper,the lightning density and radiance variation characteristics of Heilongjiang Province are analyzed by utilizing LMI Event data from June to September each year in the period of 2018 to 2021.The results show that the lightning density and radiance is unequal spatial distribution in Heilongjiang Province.The high lighting density happens in the northern,south central and western parts of Heilongjiang,and the high mean radiance occurs in northern,central and southeastern parts.The density and intensity of lightning in the east and west of Heilongjiang Province are inversely correlated.Lightning is more dense but less intense in the west and less dense but more intense in the east.The lightning events in June and July owns 78.6%of the total lighting events in one year,which is the highest incidence month.Diurnal variation of lightning frequency has“double peaks”,at 3∶00 a.m and 4∶00 p.m.The average radiance decreases with the month and the radiance distribution is right skewed.The diurnal variation of the mean radiance of lightning shows a“single peak”at around 12∶00 noon.The radiance distribution of lightning events from 2018—2021 is skewed single peak type,and the high frequency range is 0~20μJ/m^(2)/ster.