울릉분지 간극에서 해면 해류의 변동성 연구

Abstract

In order to understand the relation between the sea level and upper ocean circulation around Dokdo, sea level variability was investigated utilizing bottom pressure data taken at approximately 23m water depth near South of Dokdo for 4.5 years from May, 2000 to October, 2004 and Aviso altimetric data around the Ulleung Basin. The bottom pressure and temperature data taken from Water Level Recorder (WLR) were analyzed only from May, 2000 to September, 2003 because of the failure of pressure sensor after the Typhoon Mae-Mi. Bottom pressure data were recorded every 30 minutes and converted to sea level data after eliminating the effects from the atmospheric pressure and thermal expansion using 3-hourly surface atmospheric pressure data obtained at Ulleungdo and SST data provided by European Centre for Medium-Range Weather Forecasts. There was a good correlation between time series of satellite derived Sea Surface Height (SSH) and sea level at Dokdo and Ulleungdo. Geostrophic surface current calculated from SSH also had a good correlation with sea level difference (SLD) between Ulleungdo and Dokdo, which implies that the SLD between Ulleungdo and Dokdo would be a good predictor for surface currents in the Ulleung Interplain Gap (UIG). The estimated surface current velocity in UIG shows maxima in May or June and minima in September or October in 2001 and 2002.