Tide-Generated Internal Solitons in Bay of Bengal Excite Coastal Seiches in Trincomalee Bay (original) (raw)

MODIS/Terra/Aqua satellite sensors allowed us to obtain 250-m resolution true-color images of internal solitary waves during sun glint conditions. These internal solitons packets were generated at 8° 50.9’ N and 92° 49.3’ E, about 4 km Northwest off Batti Malv Island of the Nicobar Archipelago in the Andaman Sea during a 3-day period of strong semidiurnal surface tides. About 20 km from the origin, the packet consists of 6 to 7 internal solitary waves, but 100 km farther from the origin position the number of waves in each packet doubled. The waves were ranked in amplitude order and their intra wave distance decreased from 7 km to 2.5 km. These packets moved West (270°) and crossed 1270 km in about 5.4 days to reach the entrance of Trincomalee Bay, Sri Lanka. The average inter packet distance is 122 km, suggesting that the packets were phase locked with the internal tide. Offshore of Trincomalee Bay entrance a nonlinear internal wave field was observed. The intra wave distance was 2.5 to 5 km. A nonlinear internal wave can excite a 42-minute coastal seiche in the Bay with an amplitude of 7 cm. Using a novel approach called seichelogía we estimated that the amplitude of the nonlinear internal wave was 8 m.