大连海雾特征及形成机理初步分析  

Characteristics and Generating Mechanism of Sea Fog in Dalian of Liaoning Province

作　　者：汤鹏宇[1] 何宏让[1] 阳向荣[1] 

机构地区：[1]解放军理工大学气象学院,江苏南京211101

出　　处：《干旱气象》2013年第1期62-69,共8页Journal of Arid Meteorology

基　　金：国家自然科学基金项目(41275128)资助

摘　　要：利用2000～2010年逐3 h一次的常规报文资料和2.5°×2.5°的NCEP月平均场再分析资料,统计分析大连海雾发生时各种大气环境要素特征,确定有利于海雾生成的环境要素条件,并以此讨论海雾的成因和性质。同时,统计分析了大连海雾的年际变化与季节特征,对造成大连海雾异常偏多与偏少时的环流形势与水汽条件进行对比,分析有利于海雾生消的环流形势和海雾的水汽来源,以及海雾的性质成因。结果表明,大连海雾多发于春夏2季,其中尤以5～7月为海雾多发期,而在秋冬季很少发生。海雾主要出现于下半夜至上午前(从02点到11点),其中清晨05～08时最多,其消散一般在上午日出之后。风速在2～8 m/s之间的偏东风或偏南风最有利于大连海雾的发生。当预报海雾发生时,T-Td>0.6℃时,判断能见度>300 m;T-Td>1.1℃时,能见度一般>500 m;T-Td>2.1℃时,能见度>800 m。海雾在1 008 hPa时发生频次达到一个峰值,当气压<995 hPa和>1 030 hPa时,基本上没有海雾的生成。大连海雾多为平流雾,海雾的年际变化是大气环流变化的结果,海雾发生频数与副高西侧的偏南季风气流相关,当副高增强时,西南季风气流可以直接将热带洋面的水汽输送至大连地区,这样的平流水汽遇到冷的下垫面时,在大连海域形成海雾。Based on the conventional meteorological data of every three hours from 2000 to 2010 and the monthly average field reanalysis data of NCEP（2.5°×2.5°）,the various characteristics of atmospheric environmental elements during sea fog generation in Dalian was analyzed,and infuluences of the environmental elements on the generating and dissipating of sea fog were studied,then the environmental conditions which was beneficial to the sea fog＇s generation were obtained.At the same time,the interannual variability and seasonal characteristics of Dalian sea fog were analyzed,and the circulation situation and moisture conditions which causing the abnormal more and less sea fog were compared to study the circulation situations of Dalian sea fog generation and dissipation,as well as the moisture sources.The results show that Dalian sea fog mainly occurred in spring and summer（especially in May to July）,in a day,sea fog mainly occurred from 02：00 to 11：00 and usually dissipated after sunrise in the morning.East or south winds with 2-8 m/s were most conducive to the occurrence of Dalian sea fog.When sea fog occurred and T-Td was more than 0.6 ℃,the visibility would be forecasted more than 300 m,and T-Td was more than 1.1 ℃,the visibility would be forecasted more than 500 m and when T-Td was more than 2.1 ℃,the visibility would be forecasted more than 800 m.Sea fog frequency reached a peak at 1 008 hPa,when air pressure was less than 995 hPa and more than 1 030 hPa,no sea fog generated basically.The sea fog in Dalian were mostly advection fog.The sea fog frequency was related to the south monsoon airflow at the west side of the western Pacific subtropical high,when the subtropical high enhanced,the moisture over the tropical ocean surface could be directly transported to the Dalian area by the southwest monsoon airflow,and when the advection moisture encountered cold underlying surface,the sea fog occurred in the coast of Dalian.

关 键 词：大连 海雾 统计特征 形成机理 

分 类 号：P468.028[天文地球—大气科学及气象学]