JO: Vol.52, No.3, pp.389-398, 1996 Abstract

Journal of Oceanography, Vol. 52, No. 3, pp. 389-398, 1996

Short Contribution

Coastal Polynyas off East Queen Maud Land Observed from NOAA AVHRR Data

Takayuki Ishikawa¹, Jinro Ukita¹, Kay I. Ohshima¹, Masaaki Wakatsuchi¹, Takashi Yamanouchi² and Nobuo Ono²

¹The Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido 060, Japan
²National Institute of Polar Research, Itabashi-ku, Tokyo 173, Japan

(Received 14 March 1995; in revised form 27 November 1995; accepted 29 November 1995)

Coastal polynyas off East Queen Maud Land in Antarctica are examined using NOAA AVHRR infrared data. From image analyses, two locations of coastal polynyas in this region are identified; one in Breid Bay and the other along the shelf break. The areal coverage of the Breid Bay polynya is significantly related to the strength of katabatic winds, which maintain their strength over the coastal sea due to land topography favoring for their confluence, thereby being capable of removing newly formed ice. Land fast ice in the eastern part of the bay also plays an additional role in the formation mechanism. It is also found that the areal coverage of coastal polynyas in this region fluctuate coherently. Moreover, these fluctuations correspond to the synoptic index, which measures the strength of the offshore wind, with their peaks closely associated with the areal peaks. These facts strongly suggest the influence of synoptic scale weather on the formation and maintenance of polynyas in this region.