The relative importance of meteorological events, tidal activity and bathymetry to circulation and mixing in Kingston Harbour, Jamaica

The objective of the study was to determine the influence of meteorological events (rainfall and wind) as well as tides and bathymetry on the circulation patterns of an enclosed embayment, Kingston Harbour, Jamaica. Current velocity, water temperature and water salinity were assessed at 20 stations within the harbor between December 1993 and February 1995. Meteorological events such as rainfall, wind velocity and tidal periodicity and amplitude were determined in association with routine sampling conducted at the 20 harbor stations. Results indicated that the harbor behaves in a complex manner and is best presented in sectors (zones). The outer harbor has estuarine characteristics and appears to be driven primarily by density/salinity gradients. After heavy rainfall (>65 mm), there is an upper layer (0–5 m deep) of low-salinity water (31–35) flowing quickly (14 cm s⁻¹) out of the harbor, while below 5 m, more saline water (35–36) flows more slowly (∼ 3 cm s⁻¹) into the harbor. A characteristic of the outer harbor is a deep, but narrow shipping channel where fast currents (max = 15 cm s⁻¹) facilitate constant water renewal, thus high water quality. Inner harbor circulation is most affected by tides, but the area also comes under the influence of low salinity water flowing from Hunts Bay as well as high winds from the southeast. Greatest water movement in the inner harbor (18 cm s⁻¹) was achieved when high winds combined with ebb tidal period. The upper basin is primarily affected by winds, which induce horizontal and vertical gyres in the area with little net horizontal movement. Surprisingly, the fastest currents (24 cm s⁻¹) were recorded in the eastern section of the upper basin; however, this was under conditions of high wind (>4 m s⁻¹), high rainfall (>65 mm) and a flooding tidal cycle, which produced the greatest movement throughout the harbor.