Observed internal solitary waves in the northern Bali waters, Indonesia

Abstract

Internal solitary waves (ISWs) in the northern Bali waters are frequently observed via satellite imagery, but in situ observations remain scarce. Here, we report the northward propagating Lombok solitary waves from shipboard acoustic current measurements. The four leading waves have amplitude of 45, 35, 30, and 25 m and typical mean phase speed of ∼1.8 m s−1. The waves generated strong northward currents of ∼0.8 m s−1 in the upper layer and triggered vertical velocity that reaches ∼15 cm s−1. Those observations suggest larger ISWs amplitude than recent numerical estimates at the same location. The shape of the four leading waves is consistent with the Korteweg–de Vries (KdV) model. The total energy density within the packet reached ∼147 MJ m−1, and the total mean energy flux per tidal cycle into ISWs is in the range [0.6 – 1.0] GW, representing a strong fraction of the total northward baroclinic tidal energy flux estimated from models.