: A quantitative study was made of the heat budget of the Arctic and its relationship to the atmospheric circulation of the hemisphere. It combines the available data to produce a description of the input, transformation, and output of thermal energy in the Arctic regions and provides new insights into the mechanism of the Arctic climate. The Report points out the specific measurements most urgently needed for future Arctic investigation, if we are not only to explain some of the climatic variations of the past but also to determine how the climate of the future might be foreseen and influenced.
Since the Apr 1957 occupation of the first long-term US drifting station on sea ice, much has been learned about the properties of sea ice as a material. Properties of large, composite sheets of natural sea ice are still to be defined, however, because of the need for accurate knowledge of strength, roughness and albedo, among other parameters. In explanation of the ice cover, studies have been made of energy fluxes, radiative fluxes, albedos, wind and water flow profiles in boundary layers, air and ice temperature profiles and evaporation of condensation. There remain unresolved and complex questions concerning the circumstances under which the present ice cover could change.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.