Numerical investigation of 3-way coupled tropical cyclone (TC)-Loop Current (LC)-wave non-linear interactions

Compared to 2-way coupled simulations over the Gulf of Mexico (GOM), additional wave (3-way) coupling shifts the energy of the surface flow toward the model grid resolution (8-9 km) and showed  higher energy in the velocity potential component than the divergence component. The heat budget of the Loop Current showed differences  between 2- and 3-way coupling. e.g. the magnitude of the heat tendency and the pattern of the advection term. and also a strong TC quadrant-dependent heat budget when a TC interacts with the LC. For instance, the heat budget at the LC warm core and at a TC center was ~1.5 times smaller for 3-way coupling than the 2-way counterpart. On the other hand, the heat at the LC front and TC right-quadrant were about the same magnitude regardless of coupling, but the large negative trend for 3-way coupling at the time a TC passed was not completely accounted for by the individual budget terms. It is interesting to observe a shift from the rotational field dominant for a pre-storm period to the divergence component during the TC passage, which might be related to the storm-induced upwelling.