JP2.18
Ocean Dynamics in Recent Arctic Freshwater Changes
Xiangdong Zhang, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, AK
Freshwater changes and redistributions are salient phenomena among recently manifested changes in the Arctic climate system, whose anomalous exports may have significant impact on the deep convection and the Atlantic meridional overturning circulation (Manabe and Stouffer 1988; Hakkiene 1993). Observations and modeling experiments (e.g. Steele and Boyd 1998; McPhee et al. 1998; Zhang et al. 2003) have documented that the Eurasian Basin salinified and the Beaufort Sea freshened while the Arctic Oscillation persisted in its positive phase during the 1990s. Such changes and redistributions of the freshwater storage can predominantly attribute to the redirected Eurasian riverine water input (Steele and Boyd 1998; Zhang et al. 2003) and the changes of sea ice growth and melt (McPhee et al. 1998; Zhang et al. 2003). Horizontal transport in the upper ocean also plays an important role in the forming freshwater storage anomalies (Zhang et al. 2003). On the other hand, from the ocean dynamics point of view, it was hypothesized that freshwater may accumulates or releases corresponding to the fluctuation of overlying atmospheric cyclonic and anticyclonic forcing, namely positive and negative phase of the Arctic Oscillation. Anomalous high (low) sea level pressure may give rise to an enhanced (reduced) convergence and downwelling Ekman pumping to cause an accumulation (release) of freshwater. However, this hypothesis has not been examined intensively due to data availability. In this study, we employed an Arctic sea ice-ocean model to investigate this hypothesis and to examine ocean dynamics’ role in the recent freshwater changes.
Joint Poster Session 2, Formal Poster Viewing - High Latitude Climate Variability and Change (Joint with the Eight Conference on Polar Meteorology and the 16th symposium on Global Change & Climate Variations)
Thursday, 13 January 2005, 9:45 AM-11:00 AM
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