Existence of a huge isothermal water mass in the bottom water body of Jiaozhou Bay

Abstract

Based on the survey of the waters of Jiaozhou Bay in April and August 1981, this study examines the water temperature and geographical distribution in the bottom waters of Jiaozhou Bay. The results showed that the water temperature in the bottom water body ranged from 7.69 to 25.70°C in April and August, and the water temperature in the bottom reached 7.50°C and above. This indicates that in terms of changing water temperature, the water temperature in the bottom of the entire water body of Jiaozhou Bay was relatively high in April and August. The Yang Dongfang Water Mass and Yang Dongfang Isothermal Water Mass have been defined. Based on the definition of Yang Dongfang Isothermal Water Mass, three isothermal water masses exist in April, located in the waters of the Bay mouth and outside the Bay mouth, inner side waters of the Bay mouth, and the northern waters of the Bay. In the three isothermal water masses, the interval length of changes in seawater temperature was 0.23°C, 0.70°C and 0.00°C, respectively. The interval length of the seawater temperature was within 0.00–0.70°C. In addition, the temperature of three isothermal water masses was within 7.69–7.92°C, 8.01–8.71°C, and 9.35–9.35°C, respectively, which indicates that in April, the temperature of isothermal water mass in the northern waters of the Bay is more than the temperature of isothermal water mass in the inner side waters of the Bay which in turn more than the temperature of isothermal water mass in the waters of Bay mouth and outside of the Bay mouth. In August, there was only one isothermal water mass in the bottom waters of Jiaozhou Bay, located in the waters composed of the entire water body of Jiaozhou Bay, the waters of the Bay mouth and the outside waters of the Bay mouth. In this isothermal water mass, the interval length of changes in seawater temperature was 0.54°C; namely, the interval length of changes in seawater temperature was within 0.54–0.54°C. Moreover, the temperature of this isothermal water mass was 25.16–25.70°C. In the bottom waters of the Bay, the seawater temperature was very low in April, and it formed three isothermal water masses in the northern waters of the Bay, in the inner waters of the Bay, and the waters of the Bay mouth and outside of the Bay mouth. From April to August, under the high-water temperature effect, the entire water body of Jiaozhou Bay, the waters in the Bay mouth and the waters outside of the Bay mouth integrated to a new huge water mass. Therefore, the changes in the process of seawater temperature from April to August determined the numbers, location, size scale, and order of isothermal water mass temperature changes.