Observed Deep Anticyclonic Cap Over Caiwei Guyot
Binbin Guo, Weiqiang Wang, Yeqiang Shu, Gaowen He, Dongsheng Zhang, Xiguang Deng, Qianyong Liang, Yong Yang, Qiang Xie, Haifeng Wang, Jun Wang
Abstract
Abstract The mean circulation pattern and its mechanism over Caiwei Guyot (1,308–5,600 m) in the Northwest Pacific were studied utilizing 3 years of in situ data. A deep anticyclonic cap was found to enclose the entire guyot from its bottom up to a depth of 728 m, which is composed of a stable but highly asymmetric anticyclonic circulation at the foot and a bottom‐trapped anticyclonic circulation over the summit. On the slope, the circulation is complex with a dominant anticyclonic circulation near the bottom and a weak cyclonic circulation at ∼2,200 m. The anticyclonic cap intensity over the summit is significantly modulated by the time‐varying impinging flow. An intensified cold ring above the summit edge was observed at Caiwei Guyot, which differs from the cold domes observed over traditional conic seamounts. Further analysis suggests that the impinging flow is primarily responsible for the cap formation, and the M 2 tide‐seamount interaction plays a secondary role. The anticyclonic cap may play a role in the local geological distribution.