Variability and Formation Mechanism of Polynyas in Eastern Prydz Bay, Antarctica

Saisai Hou,Jiuxin Shi

doi:10.3390/rs13245089

Abstract

Based on satellite remote sensing, several polynyas have been found in Prydz Bay, East Antarctica. Compared with the Mackenzie Bay Polynya, the only polynya in the west, the polynyas in eastern Prydz Bay have a larger area and higher ice production, but have never been studied individually. In this study, four recurrent polynyas were identified in eastern Prydz Bay from sea ice concentration data during 2002–2011. Their areas generally exhibit synchronous temporal variations and have good correlation with wind speed, which indicates that they are primarily wind-driven polynyas that need at least one stationary ice barrier to block the inflow of drifting sea ice. The components of the ice barriers of these four polynyas were identified through comparison of satellite remote sensing visible images and synthetic aperture radar images. All types of fast ice, including landfast ice, offshore fast ice and ice fingers serving as ice barriers for these polynyas are anchored by an assemblage of small icebergs and have an approximately year-round period of variations that also regulates the variability of polynyas. The movement and grounding of giant icebergs near the polynyas significantly affects the development of the polynyas. The results of this study illustrate the important impact of icebergs on Antarctic wind-driven polynyas and the formation of dense shelf water.

Highlights

Polynyas are areas of open water and/or thin ice within pack ice in the polar oceans, where thicker ice cover would be expected [1]
Around 10% of the sea ice in the Southern Ocean is produced in the major coastal polynyas, the total area of Antarctic coastal polynyas only accounts for about
Four polynyas were identified in eastern Prydz Bay (Figure 2), based on the polynya occurrence frequency (POF) values described above

Summary

Introduction

Polynyas are areas of open water and/or thin ice within pack ice in the polar oceans, where thicker ice cover would be expected [1]. Around 10% of the sea ice in the Southern Ocean is produced in the major coastal polynyas, the total area of Antarctic coastal polynyas only accounts for about. In the Indian Ocean sector of the Southern Ocean, the total ice production in the polynyas in Prydz Bay is 30% greater than that in the Cape Darnley Polynya [10]. The latter has been identified as one of the source regions of AABW [8], the status of Prydz Bay is still controversial [10,11,12].

Results

Discussion

Conclusion