Mesoscale analysis of a polar trough interacting with a polar front
-occlusion is developed in which the key elements are (1) a moist, relatively warm, low-level jet associated with the polar trough, and (2) a major upper-level jet streak associated with the polar front. The polar trough conveyor belt and the polar front
The interaction of a polar trough with a polar front can lead to a characteristic satellite cloud pattern commonly referred to as an instant occlusion. The AA. refer to it under the name of pseudo-occlusion. A conceptual model of the pseudo
Les dépressions polaires (polarlows) sont des dépressions peu marquées, qui se développent rapidement à la faveur d'expulsions froides aux hautes latitudes comme le nord-est de l'Atlantique. Utilisation d'un modèle numérique. Trois situations, en
Les dépressions peu creusées qui se développent rapidement à la faveur d'expulsions froides aux latitudes élevées du continent nord-américain (exemple des 25-28 janvier 1977) présentent de nombreux points communs avec les polarlows ou polar troughs
Les vortex qui se forment au sein des coulées polaires (comma clouds sur le Pacifique, polarlows sur l'Atlantique) et qui, au stade de maturité, présentent des caractéristiques très voisines de celles des cyclones de front polaire, revêtent une
The genesis and evolution of lake basins on the example of the Lower lake in the marginal zone of the Elise Glacier in Results of investigations of the Second Torun polar expedition, Spitsbergen-1977 and Third Torun polar expedition, Spitsbergen
Associations between polar air cloud vortices ( polarlows ), as an indicator of intermediate-scale atmospheric activity, and the Antarctic sea ice, are examined for the Southern Hemisphere winter (June-September). Seven consecutive winters
Classification of mesoscale vortices in polar airstreams and the influence of the large-scale environment on their evolutions
estimé à partir des configurations nuageuses. Ces dernières, classées en neuf types, permettent également de distinguer, à un stade très précoce, les vortex qui resteront insignifiants de ceux qui deviendront d'authentiques dépressions polaires (polar
lows, pour lesquelles les AA. proposent une théorie très complète). (JPB).
Genesis of active sand-filled polygons in lower and central Beacon Valley, Antarctica
Antarctica ; Cold area ; Ice wedge ; Patterned ground ; Periglacial features ; Permafrost ; Polar region
In this study, the AA. describe and characterise sand-filled wedges and polygons and propose a descriptive model for their formation in lower and central Beacon Valley from detailed analysis of a 2-m resolution aerial photography and other
Effect of permafrost and palaeo-environmental history on soil formation in the lower Kolyma Lowland, Siberia
Cold area ; Cryoturbation ; Eastern Siberia ; Geochemistry ; Palaeo-environment ; Palaeosol ; Patterned ground ; Pedogenesis ; Permafrost ; Polar region ; Russia ; Sakha ; Tundra
The geogaphy of soils has been studied in the tundra of the sandy Kolyma Lowland between latitudes 69° and 70°N. Controlled by a shallow permafrost depth and low precipitation values, relict features of multiple Podzol formation are mainly
Lower palaeozoic stratigraphy of Murchisonfjorden and Sparreneset, Nordaustlandet, Svalbard
The International Polar Year project Kinnvika - Arctic warming and impact research at 80° N
The Lower Palaeozoic stratigraphy of the Kap Sparre Formation of Kulling (Hecla Hoek Succession) from Murchisonfjorden and eastern Nordaustlandet of Svalbard is described based on new field observations in the region. Additions to the previous
descriptions of some of the existing units are presented. The new lithostratigraphical unit : a Lower(?) to Middle Cambrian Black shale and limestone unit is proposed informally. In addition, a Middle(?) Cambrian to Lower Ordovician Dolostone-limestone unit
, and a (Lower to Middle(?) Ordovician) Limestone unit, which overlies the Upper dolomite series are added to the succession. The deposits as a whole show the development of an environmentally controlled carbonate platform that marked the transition from
This paper briefly summarizes current knowledge of the Muir Point Formation and discusses the significance of recent paleomagnetic information showing that the lower part of the formation has normal polarity.
pavement created during short duration high flows in earlier years. Transport rates are highly variable. An average annual total sediment discharge of 3 400 t/y. confirms earlier conclusions that sedimentation rates on Antarctic sandur are much lower than
In the lower oceanic Antarctic where particular climatic conditions are found, a special type of periglacial geosystems exists with geomorphic effected cryodynamics. The approaches to regional modelling are to be further developed because
Climatic variation ; Cold area ; Ice wedge ; Model ; Numerical model ; Palaeo-environment ; Periglacial features ; Polar region
criticisms focus on : the implications of trough evolution for cracking behaviour; the extent to which epigenetic, low-centred polygons represent the population of ice-wedge networks; and the modelled initiation of polygons in drained thaw lakes.
By the age model of the AA., the upper reaches of Hatherton Glacier have not exceeded their current elevations by more than 100-150 m during the last two complete global glacial-interglacial cycles, whereas the middle and lower reaches of Hatherton
Glacier have thickened considerably during the last two global glaciations (late Wisconsin and marine isotope stage 6). The effect of ice-shelf grounding probably was the major control of these changes of Hatherton Glacier. Holocene ice-surface lowering
radiation, sensible heat transfer and run-off production. In addition summer precipitation generated surface flow with low run-off coefficients. Suspended and dissolved sediment concentrations in surface run-off were low suggesting that slopewash