Synoptic patterns of sea fogs and coastal fogs over the Incheon International Airport (IIA) area in Korea

The Incheon International Airport (hereafter IIA), located on the west coast of Korea, often is affected by both sea fogs and coastal fogs. To understand better the characteristics of the two types of fogs, satellite imageries or the reanalysis data [Global Data Assimilation System (GDAS) from NCAR], along with the weather reports around the IIA area, are analyzed. In addition, back trajectory analyses are made to designate the air mass characteristics when the fog forms. There are 181 fog events for the five year period of 2002 to 2006 over the IIA area. First they are classified into cold water fogs (108) and warm water fogs (73) based on the temperature difference between the sea surface and the air above, i.e., the SST and the temperature at 2m ASL from the reanalysis data, because it is considered that the whole mechanism of the formation, the development and the dissipation of cold water fogs is different from those of warm water fogs. Then the fogs in each group are classified into sea fogs or coastal fogs based on the relative humidity at 2m ASL from the reanalysis data. Synoptic patterns in each case are inferred from the weather charts at surface and 850 mb. Preliminarily cold water fog events are divided into 46 sea fogs and 62 coastal fogs and they can also be classified into many subcategories, depending on the synoptic patterns. For both sea fog and coastal fog groups, the westerly or southwesterly winds dominate. However, for the coastal fog type, there are some cases where northerly winds prevail over the west coast of the Korean peninsula. A complete analysis will be shown at the conference.