2007 Annual Meeting and Arctic Forum | Abstracts

Synoptic Influences on the Arctic's Freshwater Budget: Case Studies From the Northern North Atlantic

Maria Tsukernik¹, Mark C. Serreze², David N. Kindig^3
1National Snow and Ice Data Center, University of Colorado Boulder, University Campus Box 449, Boulder, CO, 80309, USA, Phone 303-492-6115, tsukerni@colorado.edu
²National Snow and Ice Data Center, University of Colorado Boulder, University Campus Box 449, Boulder, CO, 80309, USA, Phone 303-492-2963, Fax 303-492-2468, serreze@kryos.colorado.edu
³National Snow and Ice Data Center, University of Colorado Boulder, University Campus Box 449, Boulder, CO, 80309, USA, Phone 303-492-6115, kindig@nsidc.org

The freshwater budget of the Arctic has drawn scientific attention for several decades. The shrinkage of sea ice observed in recent decades together with the increased high latitude storm activity and precipitation has a potential to alter the rate of thermohaline circulation in the North Atlantic and thus influence the global climate. The majority of research devoted to this problem has focused on a monthly and/or annual timescale. We compliment current research by looking at the key variables of the arctic freshwater budget on a synoptic timescale.

In addition to its significance in the global climate system, the northern North Atlantic region is one of the most synoptically active and variable regions of the planet, especially during the winter season. Through impacts on net precipitation and wind driven export of sea ice via Fram Strait, these cyclones can modulate arctic freshwater budget.

NCEP/NCAR reanalysis data are used to examine winter synoptic activity in the North Atlantic. The cyclone identification algorithm is based on the sea level pressure (SLP) pressure field. We use ERA-40 6-hourly fields to assess precipitation, evaporation and moisture flux and daily sea ice concentration from Nimbus-7 SMMR and DMSP SSM/I passive microwave and daily Polar Pathfinder Ease-Grid sea ice motion vectors to investigate sea ice, the later two are distributed at the National Snow and Ice Data Center (NSIDC). We identify several typical cases and analyze their regional precipitation and sea ice input.

Precipitation follows the cyclone activity closely. Generally, the more intense the synoptic system is, the more precipitation is associated with it. However, since cyclones vary in size and developmental patterns, case study approach proves to be the most valuable tool to assess precipitation. Cyclone generated low level wind have a huge effect on sea ice motion when the storm is fairly deep and fairly close to the sea ice margin. Using several case studies we illustrate these associations in greater detail.