1. Current Research: Seasonality of Arctic Mediterranean Exchanges Christoph Rieper, PhD Student, University of Hamburg, WP 2.3 Arctic Mediterranean communicates through a number of passages with Atlantic and Pacific Most volume transport happens at Greenland Scotland Ridge At GSR: All surface inflows and overflow at Faroe Bank Channel exhibit significant seasonality Approach to extract seasonal signal: time series decomposition time series = low frequency + seasonality + remainder (small, random) Bathymetry of Arctic Mediterranean Bering Strait Canadian Archipelago Greenland Scotland Ridge

2. Extracting Seasonal Signal Example: Faroe Shetland Inflow Transport Time Series = low frequency + seasonality + remainder (random) Sine fit: fixed phase and period (12 months), variable amplitude Data: volume estimates of in- and outflows within the last 20 years (ADCP, altimetry) Exhibits a strong seasonal signal strength about 30% (1 Sv) of average transport (3 Sv) Strong in winter, weak in summer Strength of seasonality (modulation of sine) varies from year to year

3. Seasonality of exchanges at Greenland Scotland Ridge Sum of individual seasonalities = seasonal balance On seasonal timescale in- and outflows are not balanced Surplus in winter, deficit in summer Net flux has to be balanced by other passages: Canadian Archipelago, Bering Strait. Seasonal volume balance (positive: inflow, negative: outflow)

4. Outlook – Research Questions What could close the seasonal balance? East Greenland Current? Continue quantification of the seasonal cycle and compare the different in- and outflows to each other: modulation of seasonal strength, phase, …

5. The research leading to these results has received funding from the European Union 7th Framework Programme (FP7 2007-2013), under grant agreement n.308299 NACLIM www.naclim.euwww.naclim.eu