Characteristics And Disaster Risk Analysis Of Storm Surge In The Yellow River Delta

The Yellow River delta had several severe storm surge disasters that caused significant economic losses and casualties to the local in history.With the establishment of the Yellow River delta Efficient Ecological Economic Zone,the economy of Yellow River delta develop rapidly and the economic loss caused by storm surge is also increasing rapidly,storm surge disaster has become an important factor affecting and restricting the economic and social development of the Yellow River Delta.Therefore,strengthening the research of storm surge disaster and reducing the loss of storm surge disaster is of great significance to ensure the security of local residents' life and property as well as to guarantee the healthy and stable economy development of the Yellow River delta.This paper utilize methods of combining meteorological science with ocean hydrological science,we apply the data of wind direction,wind speed,air pressure,hourly tidal level and astronomical tide level in Claw ditch and the Yellow River harbor observation station from 2008 to 2010 tomake statistical analyses of the characteristics of sea level,wind field and the process of storm surge,the results indicatethat :(1)The Yellow River harbor is a normal diurnal tidal zone,its tidal range is small,its tidal level is less affected by the astronomical tide and less cyclical,its mean tide level is lower,the mean tide level is the highest in August and the lowest in January,the average wind speed of Yellow River harbor is larger in December and April and smaller in August,easterly component dominates the wind direction from February to October;The Claw ditch belongs to irregular semidiurnal tidal zone,its tidal range is larger and tidal level is greatly influenced by the astronomical tide,its mean tide level is higher and the mean tide level in summer is higher than in winter,the mean tide level is the highest in August and the lowest in January,easterly component dominates the wind direction,the average wind speed is larger in April and smaller in September.(2)The typical weather conditions when storm surge happen in the Yellow River delta have three types: cold air with cyclone,northward typhoon,cold high pressure type.Storm surge led by the cold air with cyclone is more obvious and the storm surge water level is higher,most of severe storm surge disaster occur under the weather situation.(3)Wind stress is the most important factor affecting the storm surge,the continuous northeaster and superposition of astronomical high tide are the direct factors leading to the storm surge for the Claw ditch and the Yellow River harbor.Making linear fitting between the time of high tide level and the time of astronomical high tide,it is found that there is obvious correlation between the two,the highest tide level generally occur before the time of astronomical high tide level.The linear correlation between the mean wind speed and the measured peak height of the northeast wind is higher.According to the weather forecast the maximum wind speed and average wind speed of the northeast wind,through the correlation with the storm surge,we estimate the storm surge water and get highest tide level combined with the astronomical tide.Based on the time of the emergence of the astronomical high tide and the duration of the northeast wind,combined with the correlation between them,we predict the time of the high tide.(4)According to the high level of storm surge and the local loss,we make classification of the storm surge disaster.According to the terrain,coastal levee construction,coastal economic layout and the local population distribution of the Yellow River delta,we make prediction of storm surge affected areas and industries at different tidal level,conduct disaster analysis,enact defense measures of storm surge and reduce disaster losses.