2001/01/01 by Christian Haas, David N. Thomas, Jörg Bareiss · 1 citation
Earth and Planetary Sciences · #Antarctic sea ice #Arctic and Antarctic ice dynamics #Arctic ice pack #Atmospheric sciences #Climate change and permafrost #Cryospheric studies and observations #Geology #Geomorphology #Ice divide #Lead (geology) #Melt pond #Oceanography #Sea ice #Slush #Snow
paper · pdf · doi:10.3189/172756501781831864
openalex publication_date 2001/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
Abstract Ice-core and snow data from the Amundsen, Bellingshausen and Weddell Seas, Antarctica, show that the formation of superimposed ice and the development of seawater-filled gap layers with high algal standing stocks is typical of the perennial sea ice in summer. The coarse-grained and dense snow had salinities mostly below 0.1‰. A layer of fresh superimposed ice had a mean thickness of 0.04–0.12 m. Gap layers 0.04–0.08 m thick extended downwards from 0.02 to 0.14 m below the water level. These gaps were populated by diatom standing stocks up to 439 μ g L −1 chlorophyll a. We propose a comprehensive heuristic model of summer processes, where warming and the reversal of temperature gradients cause major transformations in snow and ice properties. The warming also causes the reopening of incompletely frozen slush layers caused by flood-freeze cycles during winter. Alternatively, superimposed ice forms at the cold interface between snow and slush in the case of flooding with negative freeboard. Combined, these explain the initial formation of gap layers by abiotic means alone. The upward growth of superimposed ice above the water level competes with a steady submergence of floes due to bottom and internal melting and accumulation of snow.