Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Zur Höhenänderung von Ostalpengletschern im Zeitraum 1969-1979

Eight selected glaciers in the Eastern Alps with a total area of 52 qkm have been surveyed photogrammetrically in the years 1969 and 1979, to determine the annual height change of the glacier surface by the comparison of the two different surveys. In this period of ten years the glaciers show, except for the Hintereisferner, a positive annual height change. But it is less than the change in the past period from 1959 to 1969. The increase in elevation happens mainly in the lower regions of the glaciers, while the glacier-snow-fields don't show any remarkable height changes. So the glacier advance of the sixties seem to have already reached or crossed its maximum.