Sea Fog by Southerly Warm Air over Cool Sea Waters of the Southward North Korea Cold Current along the Korean East Coast under Cyclogenesis in the Yellow Sea

Sea fog in the southeastern coastal sea of Korea was investigated on February 21 similar to 23, 2005 by WRF 3.3 meteorological model, GOES-9 and NOAA-MCSST satellite images. On February 21, as a high pressure covers whole Korean peninsula, northwesterly in the Korean eastern coast caused moderate southwestward wind driven currents, resulting in southward littoral currents due to its coastal configuration. These currents caused further the intrusion of the North Korea Cold Current (NKCC) toward the south. Although air of 3 similar to 7(0)C by cold northwesterly wind from the northern China moved over a cool pool area off the Pohang coast and it was in the easy condition of evaporation of water droplets from the sea and condensation of water vapour to form fogs under the air and sea surface temperature differences of -3 similar to -8(0)C, strong marine surface dissipated fog droplet, resulting in 65% relative humidity (RH) with no formation of fog. However, as low pressure showing an anti-clockwise wind pattern on February 22 became more intensified in the Korean northwestern coast (cyclogenesis), southwesterly wind in the Korea northern coastal sea could cause southeastward wind driven currents, which induce upwelling of deep cold waters toward the sea surface and simultaneously these currents caused further the intrusion of the NKCC toward the southeastern open sea in about 100km away from Pohang city (a cool pool of 7(0)C cold waters). As much warmer air of 7 similar to 9(0)C by strong southwesterly wind of 6 similar to 11m/s moved over the cool pool in the open sea away from Pohang city, air and sea surface temperature difference was about 2(0)C. So, the air over the cold sea must cool down to be saturated and water vapor in air to be condensed by salty condensation nuclei, resulting in the formation of sea fog or stratus cloud with 80% RH near the sea surface and vertically extended toward 1 km height.