진해만 빈산소수괴의 경년변동과 발생확률예측

Abstract

As a basic study to improve oxygen deficient water mass(ODW), the spatial and temporal variation of water quality and occurrence characteristic of ODW by using yearly observed data of water qualities from 1989 to 2006 in Jinhae bay was analyzed. Also, we estimated ODWarea, ODWvol. and ODWR in Jinhae bay. It was shown that overall water quality at 2000s has been improved by investigating the annual variations of dissolved oxygen, chemical oxygen demand, etc. From cluster analysis, Jinhae bay was classified into four regions, it was defined as South-western, Central, Northern, and Eastern region of Jinhae bay. ODW was occurred in all areas of RegionⅠ(South-western) in 1993 and 2002-2004, it was estimated about 1.92 km3 of ODW volume. ODW were not occurred in Region Ⅳ because seawater circulation was well exchanged in the eastern part of Jinhae bay. On the other hand, ODW was generated every year in Region Ⅰ, it was indicated that the south-western part of Jinhae bay is the most polluted area in Jinhae bay. ODWR was decreased in Region Ⅲ ; hence, it is shown that water quality of Region Ⅲ has been improved since operating wastewater treatment plant in 1994. The principal components are COD, DIN and DIP to affect on occurrence ODW by the principal component analysis. Also, we estimated bottom DO concentration and ODW occurrence probability during 2007-2010yr. The ODW occurrence probability was decreased about 10-30% compared with reference period(1989-2006).