Climate Variability in the region of the future Tiksi Hydrometeorological Observatory A Contribution to the International Arctic Systems for Observing the Atmosphere - IASOA

In the framework of a joint Roshydromet and NOAA project entitled "Establishing a Modern Weather Station and Research Observatory in Tiksi, Russia", a digital archive of the historical Tiksi meteorological station data (1934 to present) has been created. Statistics for 4 hour, daily, monthly and seasonally averaged data have been calculated air surface temperature, surface pressure, wind velocity, and cloudiness. These suggest that the influences of synoptic systems on temperature trends are significant. Strong trends in cloudiness, (increasing in winter and decreasing in summer) have been detected that could contribute to weak positive trends of surface air temperature during these seasons. Wind analysis reveals increased southerly winds in fall, winter and spring. Sea ice cover in the adjacent to Tiksi Sogo Bay shows significant increase in the length of the ice-free season but also some increases in the fast ice seasonal maximum thickness. The data have also been used as external forcing to study the time evolution of fast ice in the study area using the AARI thermodynamic sea ice model. Two problems have been revealed. The first is connected to the relationship between measured snow deposits and the badly determined processes of snow redistribution during snowstorms. The second problem is related to absence of an adequate description of fast ice breakup in summer and re-establishment in autumn. Both these problems are significantly improved by using the historical information as model constraints.