Description: Large-scale features of Arctic Ocean temperature and salinity distributions observed during 2007-2009 are described and discussed in the context of historical observation in order to document long-term variations. Oceanographic observations carried out in the frame of the International Polar Year (IPY 2007/2008) demonstrated unique conditions in the Arctic Ocean and seas during that period. For example, analyses of upper ocean temperature and salinity patterns 2007-2009 revealed an apparent frontal zone separating the Eurasian and Canadian Basins. We found that after 2007 the temperature and salinity trends of the surface layer of the Arctic Ocean followed the same trajectory as in the past, however their regional distribution and intensity changed. The average salinity in the surface 5-50 m layer of the Eurasian Basin in winter of 2007-2009 was higher than in the 1950s and 1970s, but did not exceed the average salinity in the early 1990s. In the Canadian Basin, the upper ocean salinity in 2007-2009 was much lower than in the 1950s-1960s. Volumetric analysis of water masses demonstrated a general increase of volume of the intermediate (150-900 m depth range) Atlantic Water (AW) temperature, with substantial rise of the upper boundary of the AW. The thermal expansion of AW in the Arctic Basin is unique during the last 20 years. The most distinct variations of the hydrographic conditions were observed in the Canadian Basin. In general, the maximum of the AW temperature decreased in 2009 relative to 2007 and the upper boundary became shallower by 50 to 150 m the Eurasian Basin. The AW salinity in 2007-2009 was not exceptional during the IPY. Observations in the deeper layers indicated that the bottom waters have become slightly warmer and less saline.

Description: The Russian icebreaker KAPITAN DRANITSYN carried out the TRANSDRIFT III expedition to the Laptev Sea (October 1 to 30., 1995), the largest ice factory in the Arctic Ocean and source region of the Transpolar Drift. In this shelf region, ice free for only three months a year, a comprehensive interdisciplinary working program concerning the causes and effects of annual freeze-up was performed. Unlike our previous expeditions to the Laptev Sea, which focused On oceanographical, hydrochemical, ecological, and sedimentological processes during the brief ice-free period in summer, this expedition studied these processes during the extreme physical change through the onset of ice formation in autumn. This is the first study of its kind under these conditions, and gave important clues to the rapid (14 to 40 days) freeze-up, which has significant year-round effects for the Laptev Sea and global environment. Freeze-up began one month later than usual (a 40 year record) close to the Novosibirskie Islands in low salinity surface waters due to heat stored in an intermediate water layer between 10 and 25 m water depth. Later, huge tracts of turbid, dirty ice were found off the Lena Delta where an unusually high phytoplankton concentration for this time of year occurred. The origin of these anomalies, and whether they are anomalies at all, and their relationship to global environment in real time are the focus of continuing research.