Description: Sediment transport dynamics were studied during ice-free conditions under different atmospheric circulation regimes on the Laptev Sea shelf (Siberian Arctic). To study the interannual variability of suspended particulate matter (SPM) dynamics and their coupling with the variability in surface river water distribution on the Laptev Sea shelf, detailed oceanographic, optical (turbidity and Ocean Color satellite data), and hydrochemical (nutrients, SPM, stable oxygen isotopes) process studies were carried out continuously during the summers of 2007 and 2008. Thus, for the first time SPM and nutrient variations on the Laptev Sea shelf under different atmospheric forcing and the implications for the turbidity and transparency of the water column can be presented. The data indicate a clear link between different surface distributions of riverine waters and the SPM transport dynamics within the entire water column. The summer of 2007 was dominated by shoreward winds and an eastward transport of riverine surface waters. The surface SPM concentration on the southeastern inner shelf was elevated, which led to decreased transmissivity and increased light absorption. Surface SPM concentrations in the central and northern Laptev Sea were comparatively low. However, the SPM transport and concentration within the bottom nepheloid layer increased considerably on the entire eastern shelf. The summer of 2008 was dominated by offshore winds and northward transport of the river plume. The surface SPM transport was enhanced and extended onto the mid-shelf, whereas the bottom SPM transport and concentration was diminished. This study suggests that the SPM concentration and transport, in both the surface and bottom nepheloid layers, are associated with the distribution of riverine surface waters which are linked to the atmospheric circulation patterns over the Laptev Sea and the adjacent Arctic Ocean during the open water season. A continuing trend toward shoreward winds, weaker stratification and higher SPM concentration throughout the water column might have severe consequences for the ecosystem on the Laptev Sea shelf.

Description: The large scale features of the vertical thermohaline structures in the Arctic Ocean during 2007-2009 were considered to reveal the changes in temperature and salinity in comparison with the historical data. In general, the main features of vertical thermohaline structures have remained unchanged over the Arctic and demonstrate the frontal barrier area between Eurasian and American basins. However, the unique summer atmospheric forcing in 2007 resulted in the considerable thermohaline changes in the surface layer. The large areas of positive and negative anomalies in temperature and salinity have been formed over the Arctic Ocean. The volumetric changes in the water masses with different temperature and salinity gradation have been also observed. The volume of Atlantic Waters with temperatures above 0°C and salinity above 34,6 increased at 22% in 2007 in comparison with 1970-1979 mean. The changes in the deeper layers habe also been revealed. Thus, the volume of intermediate waters with temperatures ranged from -0,4 to 0°C and salinities above 34,6 decreased at 30% in 2007. The most saline and cold bottom waters became warmer and fresher.

Description: This paper examines the temperature and salinity patterns and evolution in the surface layer of the Arctic Ocean in 2007-2009 and deals with the factors impacting the extreme changes both in temperature and salinity in 2007. The large areas of positive and negative anomalies in temperature and salinity have been formed over the Arctic Ocean with the apparant frontal barrier areea between Eurasian and American basins. The followed years (2008-2009) exhibit the reducing of thermohaline anomalies between the two basins assuming gradually rcovering to the initial state. Considering the mean salinities within 5-50 m depth one can claim that the positive linear trend is evident both in Eurasian and American basinss since 1950 to 1993 while the intensive freshening was obsserved in American basin in 2007-2009. We intend that these changes in salinity can be assumed as the signature of non-stationary nature of all Arctic marine environments.

Description: Oceanographic studies during IPY 2007/2009 provided new information on spatial variability of hydrographic parameters. Detailed pattern of irregularities in the Atlantic Water (AW) layer was documented in the Nansen Basin. Spatial scales of temperature distribution and the depth of the upper boundary of AW were estimated. In the Canadian Basin spatial variations of temperature were less pronounced. During IPY 2007/2008 the area occupied by AW has increased. According to our estimations the positive temperature anomaly in some regions was as high as 1,5°C, which is about 70% of temperature maximum in 1950-1959. The upper boundary of AW (zero degree isotherm) rose by 40-120 m around the Mendeleyev Ridge and in the Amundsen Basin. At the same time, in the Canada Basin and in the western Fram Strait the AW thickness decreased by similar value. Heat content of the AW layer around the major part of the Arctic Ocean exceeded mean climatic value, except for the compact area north of Franz Josef Land, where small negative anomaly was observed. Throughout 2008 mean temperature and maximum temperature in the AW layer were higher than mean climatic values. At the same time, the state of AW layer in the inflow region, east of Fram Strait along the continental margin to the Laptev Sea, substantially changed in comparison with 2007. Mean and maximum temperature of AW dropped by 0,25/0,5°C. Heat content and the Thickness of AW layer have also decreased. Basing on the obtained results, we conclude that during 2008/2009 there was a neneral reverse trend in AW parameters towards mean climatic results.