Basal Channel System and Polynya Effect on a Regional Air‐Ice‐Ocean‐Biology Environment System in the Prydz Bay, East Antarctica

Abstract

AbstractThe interaction of air‐ice‐ocean‐biology plays a key role in the global environment and sea‐level changes. The basal channel at the bottom of the Amery Ice Shelf (AIS) and the Mackenzie polynya are the intense sites for the interaction of air‐ice‐ocean‐biology in the Prydz Bay. In this study, the spatio‐temporal distribution characteristics of the complex basal channel system from the 1990s to 2019 are discovered and analyzed. The shapes of the channels are inverted‐V in the deep parts, gradually becoming inverted‐U as it develops in accordance with the direction of erosion. The deepest part of the basal channel system is over 800 m resulting from the meltwater plumes at the southernmost grounding zone. The linear and thinner channel region is the weakest and most sensitive part under ocean forcing leading to instability of the AIS (e.g., longitudinal fractures and calving). Conductivity‐temperature‐depth data are used to confirm the paths and shapes of the warm and cold water in the interaction. Channels can be divided into warm and cold‐water channels based on filled water masses. Cold water channels collect the fresh melting water and drain it out. Paths of cold‐water columns from different channels extend to the Mackenzie polynya area, which prevents warm water from entering the west AIS. Meltwater from the channels, warm water, brine produced by the Mackenzie polynya, and marine mammals in the polynya together constitute a complex regional environment system of dynamical air‐ice‐ocean‐biology interactions.