Seasonal cycle of the Antarctic coastal ocean

Under the Japanese Antarctic Climate Research (ACR) program, year-round oceanographic observations were conducted in the vicinity of Lutzow-Holm Bay, during 1990-1992. It was found that the thickness of the Winter Water (WW) layer, characterized by a cold fresh oxygen-rich water, exhibits its maximu...

Full description

Bibliographic Details
Main Authors: Kay I. Ohshima, Takatoshi Takizawa, Shuki Ushio, Toshiyuki Kawamura
Format: Article in Journal/Newspaper
Language:English
Japanese
Published: National Institute of Polar Research 1997
Subjects:
Online Access:https://doi.org/10.15094/00008978
https://doaj.org/article/54074bd8c6e44d27b601f329139a662f
Description
Summary:Under the Japanese Antarctic Climate Research (ACR) program, year-round oceanographic observations were conducted in the vicinity of Lutzow-Holm Bay, during 1990-1992. It was found that the thickness of the Winter Water (WW) layer, characterized by a cold fresh oxygen-rich water, exhibits its maximum in the austral fall (typically 500m) and its minimum in the austral summer (typically 350-400m). The associated density variation of the water column explains only about one third of the seasonal variations in sea level at the coast, which suggests a large seasonal variation in barotropic coastal flow. Prominent freshening occurs in the WW layer during fall. This appears to be caused by the accumulation of WW, whose upper portion is freshened in the preceding summer. We think that this accumulation of the freshened (accordingly less dense) water is a possible reason why bottom water formation can not occur in this area. We propose that the seasonal variation in the WW layer is mainly caused by the seasonal variation in the wind over the coastal ocean. In fall the prevailing easterly wind intensifies, which increases the Ekman convergence of WW in the coastal ocean, while in summer the opposite occurs.