西海 中部沿岸의 海霧發生과 內陸流入에 관한 硏究

Abstract

Sea fog causes not only enormous economic losses but also human resource ones, so it is very important to forecast sea fog exactly. In spite of the fact that there were lots of sea fog study, thoes are not sufficient that the interaction between the sea and the air, which plays an important role in forming sea fog, and sea fog inflow into the land. Based on Kyoungki bay where dense sea fog occurs frequently, this study, therefore, found out the features of sea fog for the costal region in the mid-West Sea by way of statistic correlation of the synoptic observation and the features of sea fog occurrence in the point of heat exchange process between the sea and the air. In addition, the mechanism of sea fog inflow into the land was figured out. The results were summarized as follows ; 1. The frequencies of sea fog increase gradually from April, and July is the most frequent period of sea fog occurrence in spite of the fact the frequencies decrease from August. The frequencies in relation to time have the maximum period around 7 A.M and the minimum period around 15 P.M. 2. There are some synoptic patterns which facilitate a sea fog settlement, and they have periodic features. Sea fog frequently occurs in the high in the south and Low in the north synoptic pattern, and the High in the east and Low in the west synoptic pattern. Moreover, southwesterly winds are the main wind directions that cause sea fog. 3. The amount of heat is transferred to the sea, and the sea acquires more heat from the sensible heat than the latent heat because SST around Kyoungki bay is lower than the air temperature during summer. 4. In spite of the fact the amount of heat, transferred by a latent heat from the air to the sea, is more in case of sea fog settlement, the amount of heat, moved by a sensible heat, is almost the same regardless of whether sea fog settles or not. We, therefore, find out the degree of an air mass is an important factor for settling sea fog, as well as, the latent heat caused by a radiational cooling is very important factor. 5. It is judged that an ebb and flow front around Kyoungki bay and Taean peninsula play an important role in the beginning of a sea fog settlement when we analyze the spatial distribution of the West Sea surface temperature. In other words, if an air mass moves across the direction of an ebb and flow front, it is considered that sea fog settles easily because the air is saturated and condensed. 6. Sea fog settles when SST is 1℃ to 4℃ lower than 1000hPa temperature and it is 1℃ to 4℃ higher than 850hPa temperature. And, sea fog forms most frequently when the winds of 1000hPa and 850hPa are the southwest direction. 7. In the sea fog inflow into the land distribution, low frequencies of sea fog inflow during a day means that a sea wind doesn't play an important role in the movement of sea fog. It is considered that thermal blocking caused by radiational heating during a day prevents the sea fog from moving into the land. 8. The inflow of sea fog into the land was frequently occurred around the time before and after 2hours of a high tide time. It is considered that a high tide provides the land with a lot of amounts of humidity and it makes the thermal environment which is easy to inflow of sea fog. 9. The thermal blocking in the land is formed when air temperature in the land is 4℃ or more higher than SST and it decreases the inflow of sea fog into the land. That is, sea fog doesn't move to the land under condition that the difference between TA and TSS is more than 4℃(TA - TSS 〉 4℃) 10. Numerical Model shows a stable atmospheric feature in a sea fog location due to a moist Richardson number 1 through 4, in contrast to a negative value(means a strong turbulence) for the head of sea fog. Sea fog, formed under the stable condition, doesn't expand across a strong turbulence area. 11. This study has meaningful results of a regional wind direction and a speed, an ebb and flow front and a coast sea fog settlement, a humidity difference relating to visibility, the relation between the sea fog inflow into the land and a high tide, and the difference between SST and air temperature(TA - TSS 〉 4℃) after we analyzed synoptic observations and satellite images which can scan the sea fog at the sea low level.