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Climatic Features and Statistical Prediction about Sea Fogs in 3 Islands of Yellow Sea and Bohai Sea

Author: WangYanBin
Tutor: LiuQinYu
School: Ocean University of China
Course: Environmental Engineering
Keywords: Yellow Sea&Bohai Sea sea fogs Xiaoping island Haiyang island Chaolian island extend forecast climatic characteristic
CLC: P732
Type: Master's thesis
Year: 2008
Downloads: 22
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Abstract

Forecast of fogs in Yellow Sea & Bohai Sea area plays an important role in the development of marine economy and the assurance of shipping safety.The meteorological data in fog season at Xiaoping island observation from 1993 to 2002, Haiyang island observation from 1995 to 2006 and Chaolian island observation from 1980 to 1989 have been used to analyse the features of sea fogs around those 3 islands. The forming reason of fogs around those 3 islands in Yellow Sea&Bohai Sea is explained based on the variation of sea surface water temperature influenced by the ocean current,the moisture and temperature,degree of stability and wind field of atmosphere,which are influenced by the synoptic process.For reasons mentioned above,way of station fogs’statistical forecast is put forward.Research results of this thesis are listed below:Foggy probability and foggy days of Xiaoping island from April to July are increasing.One-day fogs are most in May,two-day in June,and three-day in April.Sea fogs of the Yellow Sea are mainly concentrated from the last ten day period of May to that of July.From the first ten day period of August,it begins to decrease rapidly,and from that of October,it begins to increase slowly.Fog dissipation time is concentrated on 7a.m.-10a.m.after sun-rising&8 p.m..Fogs’daily variation of Chaolian island is smaller than Haiyang island.There are 3 foggy centers from south to north for the space distribution of the Yellow Sea fogs:around the mouth of Changjiang River from March to May,around Qingdao from May to June,and around Chengshantou in July.In the Yellow Sea foggy season,the foggy region is extended from east to west.In some months,almost the whole Yellow Sea is foggy season.Sea fogs of Chaolian island and Haiyang island have obvious yearly variation,and the yearly fog days’period is 5 years.Hydrometeorological conditions for Chaolian island to have the largest foggy probability are given below:when the air temperature of Chaolian island minus the sea temperature is 0-1℃for average,the wind direction is SSE,the wind force is 3-4 degree,the atmosphere of Pyongrang is bigger than that of Chaolian island.It is found that a small range of foggy area in the Yellow Sea being observed in the visible cloud map,the current field’s changing,the wind field of the East China Sea and the inversion layer being found in the surface layer can all be treated as basis for the forecast of the Yellow Sea fogs’out-growth&dissipation.After making a conclusion for Chaolian island sea area’s sea fog forecast from the synoptic angle,we make the extending forecast of fog days in the way of principal component analysis,set up the forecast equation,and the tendency forecast’s accuracy is 85%.On base of making the climatic characteristic analysis for Chaolian island sea area’s sea fogs in the foggy season:we put forward the method of making the extending forecast of fog days in the way of principal component analysis,forecast fogs’lasting time in the way of 0-1 time series period analysis,and make the assembly forecast of fogs’ appearing time using Markov Chain.By those ways discussed above,short-time forecast test of those sea areas’fogs have been made.and the results are inspiring.

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