利用1909—2008年共100年间的国际综合海洋-大气资料集(International Comprehensive Ocean-Atmosphere Data Set,ICOADS)对北太平洋和东亚海域海雾的发生频率及海雾发生时主要气象要素特征进行了分析。研究发现,北太平洋海雾主要发生在中高纬度海域,从北海道到阿留申群岛以南的海域是海雾发生频率较大的地区,海雾发生频率的最大值在40%以上,而在低纬度海域海雾频率几乎为零。4⁸月是北太平洋上发生海雾较为频繁的季节,4⁷月中国近海海雾主要发生在黄海、东海和渤海海域。6月份山东半岛以南海域海雾最大频率可达20%,进入8月后,海雾频率突然降低到5%以下。海雾发生时,千岛群岛以东海域风向主要以南风为主,其次为东南风和西南风居多,海上风速在4.4~12.3m·s-1之间。海雾发生时气温通常接近于露点温度,甚至有部分低于露点温度。海雾发生前,千岛群岛以东海域上气海温差多在-1³℃之间。

In this paper,the International Comprehensive Ocean-Atmosphere Data Set(ICOADS)is utilized to investigate the temporal and spatial distribution of sea fog over the Northern Pacific and the East Asian Seas,as well as the characteristics of meteorological elements that are favorable for sea fog occurrence.The"occurrence frequency"of sea fog(hereafter"sea fog frequency ")derived from ICOADS covering 100-year from 1909 to 2008is examined to display the monthly distribution of sea fog frequency based upon two grid sizes(2(°)×2(°)over the Northern Pacific,but 1(°)×1(°)over the East Asian Seas).It is found that sea fog mainly occurs over the middle-and high-latitude regions of the Northern Pacific.The sea fog frequency from the Hokkaido to the Aleutian Islands is larger,and its maximum value is above 40%in June and July.However,the sea fog frequency over the low-latitude waters is almost zero.The period from April to August is a most frequent season for sea fog occurrence over the Northwestern Pacific.From April to July,sea fog mainly occurs over the Yellow Sea,the East China Sea and the Bohai Sea.In June,the maximum value of sea fog frequency over the southern waters of Shandong Peninsula may reach to 20%.After August,the sea fog frequency over the seas may suddenly reduce below to 5%.Corresponding to the synoptic observations,the relationship between sea fog occurrence and meteorological elements is also discussed in the vicinity of Kuril Islands.When the atmospheric horizontal visibility is less than 1 000 m,usually the southerly,southeasterly and southwesterly are dominated over the oceans,and the wind speed is from 4.4to 12.3ms-1.And the air temperature is usually close to dew-point temperature,and sometimes even lower than dew-point temperature.In the east region of the Kuril islands before the sea fog occurrence,the temperature difference between air and sea is around-1³ ℃.