The division of isothermal water mass under low temperature

Abstract

Based on the dataset of Jiaozhou Bay waters in August and November 1981, the water temperature and geographical distribution in the bottom waters of Jiaozhou Bay were studied. The results showed that the water temperature in the bottom water body ranged between 12.13 and 25.70°C in August and November, and the water temperature in the bottom reached 12.00°C and above. It indicated that the water temperature in the bottom of the entire water body of Jiaozhou Bay was relatively high in August and November. The author himself defined the Yang Dongfang Water Mass and Yang Dongfang Isothermal Water Mass. By the definition of Yang Dongfang Isothermal Water Mass, there was only one isothermal water mass in the bottom waters of Jiaozhou Bay, located in the water area composed of the entire water body of Jiaozhou Bay, the waters of the Bay mouth and the outside waters of Bay mouth. In this isothermal water mass, the interval length of the changing seawater temperature was 0.54°C; the interval length of the changing seawater temperature was within 0.54–0.54°C. Moreover, the temperature of this isothermal water mass was 25.16–25.70°C. In November, there were two isothermal water masses in Jiaozhou Bay in the bottom water area, located in the Bay mouth and the inner side of the Bay mouth, and the outside of the Bay mouth. In these two isothermal water masses, the interval length of seawater temperature was 0.84°C and 0.00°C, respectively; namely, the length of the variation range of water temperature was 0.00–0.84°C. Moreover, the temperature of the two isothermal water masses was 12.13–12.97°C and 13.40–13.40°C, presenting that in November, the isothermal water mass temperature in the outside waters of the Bay mouth is more than the temperature of isothermal water mass in the Bay mouth and inner side of the Bay mouth. In August, in the bottom waters, the seawater temperature was very high, forming a huge isothermal water mass composed of the entire water body of Jiaozhou Bay, the waters in the Bay mouth and the waters outside of the Bay mouth. From August to November, under low water temperature, the huge isothermal water mass in the entire Jiaozhou Bay waters, the waters of Bay mouth, and the waters outside of the Bay mouth were separated into two new water masses: the water mass in the inner side of the Bay mouth and the Bay mouth, and the waters outside of the Bay mouth. Therefore, the changing process of seawater temperature from August to November determined the variation of the number, location, size scale, and temperature of isothermal water mass.