西南印度洋龙方斤热液区羽流信号的检测与通量估算

热液流体在物理化学特征方面与周围海水存在较大差异,探测温度异常和浊度异常是寻找热液羽状流信号的重要手段。本文采用“大洋一号”科考船第20航次的拖曳CTD数据和浊度数据,以及21航次的定点CTD数据,研究了西南印度洋龙方斤热液区的温度异常和浊度异常现象。研究表明热液区中性浮力层在水深2 550~2 650 m间,厚度约为100 m,温度异常达0.01 ℃;水深 2 750~2 800 m间亦有温度异常,最大可达0.08 ℃;温度异常水深处存在相应的浊度异常。深层背景海水位温和位密间存在简单线性关系。此外,经初步估计,热液活动区初始浮力通量为8.78×10^-4 m⁴/s³;通过中性浮力层估算热液热通量,约为130±43 MW。

Detection and flux estimation of hydrothermal plumes in the Longqi hydrothermal field in the Southwest Indian Ocean

Compared with the surrounding seawater, hydrothermal fluid has big differences in both physical and chemical characteristics. Detecting abnormal temperature and turbidity are important means for finding hydrothermal plumes signal. The towing CTD and the turbidity data from leg 20 and the CTD station data from leg 21 of “DaYang Yi Hao” expedition ship were studied. A neutral buoyancy level at the depth of 2 550~2 650 meters with a temperature anomaly about 0.01 degree, and the thickness about 100 meters is found in a hydrothermal field at 49.65°E in the Southwest Indian Ocean. It also shows that temperature anomaly appears at the depth of 2 750~2 800 meters, with the maximum value to 0.08 degree. Accompanied by temperature anomaly, turbidity anomaly also occurres at the same water levels. The potential temperature of background water shows a linear correlation with the potential density in the deep sea. In addition, it is estimated that the initial buoyancy flux is 8.78×10^-4 m⁴/s³, and the estimation value of the hydrothermal area heat flux is about 130±43 MW calculated from the neutral buoyancy level.