Graph showing temperatures in four different depth layers over time
Time series of temperatures in four different depth layers (see inset legend) show the rapid (hours) and large (3-5C) changes from three warm (labelled 2,3,5) and two cool (1,4) temperature peaks associated with the passage of internal solitary waves inferred from coastal acoustic tomography (CAT) observations in Lombok Strait, Indonesia. Credit: Syasmudin et al. [2019], Figure 4a, lower panel
Source: Geophysical Research Letters

Internal solitary waves are generated when strong tides interact with steep ocean bathymetry to produce rapid, deep-reaching and intense changes in the ocean temperature, along with enhanced turbulence and mixing of the water column that can influence biological productivity.

The relatively narrow Lombok Strait in Indonesia is a known generation area of internal solitary waves that are visible as surface slicks in remotely sensed synthetic aperture radar (SAR) images. However, the SAR snapshots provide little details about the abrupt subsurface changes associated with internal waves.

Syasmudin et al. [2019] observed the subsurface structure of the sequential passage of internal solitary waves in Lombok Strait for the first time using a moored coastal acoustic tomography (CAT) array. The inferred temperature changes with depth associated with the waves show alternating warm and cold peaks of 3 to 6°C appearing over periods of hours that were coherent over the upper 600 meters in the water column. While the internal waves are linked to the diurnal tidal cycle interaction with the strait sill, they are superimposed and potentially influenced by the large-scale background from the southward flowing Indonesian Throughflow in Lombok Strait.

Citation: Syamsudin, F., Taniguchi, N., Zhang, C., Hanifa, A. D., Li, G., Chen, M., et al. [2019]. Observing internal solitary waves in the Lombok Strait by coastal acoustic tomography. Geophysical Research Letters, 46.

—Janet Sprintall, Editor, Geophysical Research Letters

Text © 2019. The authors. CC BY-NC-ND 3.0
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