The Study Of The Relation Between Lightning Flash And CINRAD Doplar Radar's Echo In The Middle Area Of Guangdong

Based on the lightning flash data in 2004 in Guangdong area, and CINRAD Doplar radar data in Panyu, Guangzhou. The cloud-to-ground lightning's season change in 2004, and positive and negative lightning's daily change from April to August in 2004 in the middle area of Guangdong had been analyzed. It is chiefly studied that the statistic relation between the overall negative lightning frequency A, the overall negative lightning frequency B, averaged negative lightning density, negative lightning point and so on, and Doplar radar echo's intensity and height or elevation . Some conclusions in this paper as followed:(l)The cloud-to-ground frequency's season change is double apexes pattern in 2004 in the middle area of Guangdong, its value is larger from June to September, mainly apex lies in July, inferior apex in September. Most of the cloud-to-ground lightning reaches to 20000 units, which is much more than positive.(2)As the relation of the overall negative lightning frequency A in the middle area of Guangdong and CAPPI radar echo's intensity is analyzed, find that the highest value of the overall negative lightning frequency A is 30x104. In middle levels (4-16 level), when has stronger echo (12-45dBz), its value is higher. In 5-8 level 42-50dBz echo, or in 10-16 level 28-40dBz echo, averaged negative lightning density is larger than 9 times every point. As the relation between the negative lightning and CAPPI radar echo's height is analyzed, find that in height from 3km to 5km,if echo's intensity is 33-42dBz, then the value of the overall negative lightning frequency A is larger, its largest value reaches to 120><104 times every point. As the relation between negative lightning point and CAPPI radar echo, find that in 6-14 level 10-35dBz echo, the overall negative lightning point is more. In 1-5 level or 15-18 level 5-54dBz echo, the overall negative lightning point is less. In 6 level 25-36dBz echo, when negative lightning density is 1 times every point, the value of the overall negative lightning point is most, which reaches to 10000.And its value is slower reduce when negative lightning density is augment. In 1-10 level 44-5 ldBz strongest echo, the probabilities of every point which has negative lightning flash is from 0.4 to 0.7, in 10-16 level 25-44dBz stronger echo, it is from 0.1 to 0.6.(3) As the relation of the overall negative lightning frequency A in the middle area of Guangdong and PPI radar echo's intensity is analyzed, find that in 0.5 degree and 1.45 degree elevations, when echo intensity is about 40dBz, the overall negative lightning frequency A has largest value, which reaches to 30x104 times. From the relation between the overall negative lightning frequency A and PPI radar echo's elevation, find that in 0.5 degree elevation 40-46dBz echo, the value of the overall negative lightning frequency A is larger than 80x104 times. As the relation between the negative lightning point and PPI radar echo's intensity in all elevations, know thatin 0.5 -2.40 degree elevation 30-40dBz echo, the negative lightning point is most, which reaches to 40000 points. In 0.5degree elevation, when the negative lightning density is 1 times every point, the concentricity of the negative lightning flash activity is high to 0.3.In the end, show examples to prove that the statistic relation between the negative lightning frequency, position and the same period's CAPPI radar echo's echo is dependable. And caculate the half an hour's change of the echo's intensity and position with extrapolation, then forecast the position and frequency of negative lightning. The method of extrapolation is dispensable tool to nowcasting of the negative lightning.