The changing physical environment of Ny-Alesund Svalbard

Full article: Ice-core records show that climate changes in the past have been large, rapid, and synchronous over broad areas extending into low latitudes, with less variability over historical times. These ice-core records come from high mountain glaciers and the polar regions, including small ice caps and the large ice sheets of Greenland and Antarctica.

ABSTRACT: The simplest possible model is proposed to explain a large fraction of the millennial climate variability measured in the isotopic composition of Antarctic ice cores. The model results from the classic bipolar seesaw by coupling it to a heat reservoir. In this “thermal bipolar seesaw” the heat reservoir convolves northern time signals with a characteristic timescale. Applying the model to the data of GRIP and Byrd, we demonstrate that maximum correlation can be obtained using a timescale of about 1000–1500 years. Higher correlations are obtained by first filtering out the long-term variability which is due to astronomical and greenhouse gas forcing and not part of the thermal bipolar seesaw. The model resolves the apparent confusion whether northern and southern climate records are in or out of phase, synchronous, or time lagged.

A central issue in climate dynamics is to understand how the Northern and Southern hemisphere couple during climate events. The strongest of the fast temperature changes observed in Greenland (so called Dansgaard-Oeschger events) during the last glaciation have an analogue in the temperature signal of Antarctica. A comparison of the global atmospheric concentration of methane as recorded in ice cores from Antarctica and Greenland permits a determination of the phase relationship (in leads or lags) of these temperature variations. Greenland warming events around 36 and 45�kyr before present lag their Antarctic counterpart by more than 1�kyr. On average, Antarctic climate change leads that of Greenland by 1-2.5�kyr over the period 47-23�kyr before present. Diagrams. Article in Nature 394, 739-743 (20 August 1998) | doi:10.1038/29447; Received 1 September 1997; Accepted 13 February 1998

3rd time

ScienceDaily (Feb. 21, 2008) — The return of the last of three Antarctic marine science research vessels marks the culmination of one of Australia's most ambitious International Polar Year projects, a census of life in the icy Southern Ocean known as the Collaborative East Antarctic Marine Census (CEAMARC).