Study on spatiotemporal distribution characteristic of strong breeze and strong crosswind in Jiangsu section of the Yangtze River waterway

Based on the observed data of the automatic weather monitoring system( AWMS) in Jiangsu section of the Yangtze River waterway during 2009 to 2012,in this paper,the spatiotemporal distribution characteristic of strong breeze and strong crosswind was analyzed to explore the impact of the atmospheric background,geographical environment on the two kinds of winds,and the wind pressure early warning mechanism applied to the waterway was established. The results are as follows:( 1) The diurnal and seasonal variations of the strong breeze and strong crosswind are similar.( 2) The extreme maximum wind speed of every month is more than 10 m /s,both of which reaches the standards of the maximum wind event and extreme strong wind event.( 3) Different local geographic environments have different impact on the occurrence frequencies of strong crosswind in different parts of Jiangsu Section of the waterway.( 4) The prevailing direction of the strong breeze mostly belongs to the strong crosswind.On the whole,the frequencies of northerly winds are higher than that of southerly winds,and the frequencies of westerly winds are higher than that of the easterly winds.( 5) Considering the temporal and spatial variations of wind direction and speed,a four-grade early-warning system of wind pressure in the transportation of this waterway is preliminarily established. The back substitutions displayed that the spatial distribution of wind pressure in this 4grades was closely related to the terrain. The highest wind pressure grades and the most early-warning times distribute in the middle part,next highest grade and frequencies distribute in the east part,and the lowest grades and the least frequencies of strong crosswind are in the western part.