| As economy and technology develop quickly in recent society, the range to be struck by lightning will be wider, risk of lightning disasters grows gradually once lightning disaster happens, it will cause significant damage to human, society and environment, particularly the emergence of some high-tech products, they are too sensitive to be easily damaged by lightning. A large number of lightning disasters make people's awareness of risk rise progressively. Research about risk has begun gradually in order to protect against lightning. Lightning risk assessment beforehand can reduce losses effectively. Nowdays, experts and scholars at home and abroad have made standards of lightning risk assessment, but they are only for single building, lightning risk assessment for large-scale port is still few.Based on studies of lightning risk assessment at home and abroad, this paper explores lightning risk assessment methods about port, extracts risk factors, researches on techniques, divisions of risk results and so on, then gives suggestions to guide lightning protection.Firstly, this paper analyzes disaster-causing factors, vulnerability of land and past lightning disasters to identify risk of port. According to lightning data from lightning location system of Jiangsu Provincial Meteorological Bureau and annual thunderstorm days of Rudong from 1959 to 2009, temporal and spatial distribution of lightning activity at Yangkou Port have been analyzed. Results show that uncertainty of thunderstorm occuring is great, the monthly distribution of thunderstorm shows a single peak, most thunderstorms appear in July. Lightning concentrates from 11:00 p.m. to 19:00 p.m. of June, July and August. Average flash intensity of each month is between 30kA and 90kA with the maximum in November. Lightning happen most frequently in Changsha District, the density is a little higher than that of Huangang District which is still higher than the density of artificial island. Lightning density of ground is obviously higher than that of ocean, the density over waters decreases gradually from west to east, density gradient of coastal area is big. The average lightning intensity of the whole port is 33.5kA. The intensity is relatively weak around the island while that near the coast is strong. The thunderstorm cloud from northwest and local places affect Yangkou Port a lot. Study of complex soil properties of artificial island proves that soil resistivity is big which is dangerous if struck by lightning because of the difficulty to discharge. According to lightning disaster records in Rudong of past 10 years, this paper calculates the grades of lightning disasters by AHP, the result is relatively heavy.In terms of differences of building types, nature and population distribution between different areas in port, meteorological index, the indicators of environmental, risk indicators of disaster bodies and protection indicators of buildings are extracted to calculate the regional risk of artificial islands and Changsha District. The results show that comprehensive risk rating of artificial island is moderate, dry bulk and cargo area is high-risk area of casualty loss, liquid bulk tank and the LNG terminal areas are high-risk areas of building loss. Integrated risk level of Changsha District is high, liquid bulk storage and logistics area and industrial area are high risk of casualty loss and higher risk of building loss.Finally, with the results of risk identification and estimation, evalutions are given on proposed factors, it is also recommended that weather systems, physical parameters, satellite, radar and electric field mill can be used together for lightning warning. At last, the impact of lightning early warning on risk assessment is discussed.
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