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Sea State and Boundary Layer Physics of the Emerging Arctic Ocean Office of Naval Research, Code 32, Arctic and Global Prediction, Department Research Initiative Inves&gators: J. Thomson, V. Squire, S. Ackley, E. Rogers, Y. Fan, A. Babanin, P. Guest, T. Maksym, P. Wadhams, S. Stammerjohn, C. Fairall, O. Persson, M. Doble, H. Graber, H. Shen, J. Gemmrich, S. Lehner, B. Holt, T. Williams, J. Bidlot, F. GirardArdhuin, W. Perrie, J. Brozena Program managers: Mar&n Jeffries, ScoR Harper Mo&va&on Climatology & Models Measurements hRp://www.apl.washington.edu/project/project.php?id=arc&c_sea_state Nome Dutch Harbor 500 m Ice edge deployments (buoys, AUV, UAV) Pack ice stations (on-ice array, AUV under-ice transects, LiDAR, EMI, CTDs) Transects and flux stations (Met, UAV, AUV, LiDAR, EMI, CTDs, buoys) Underway (met tower, wave radar, underway CTD, cameras) Open water stations (mooring, buoys, CTDs, glider, AUV AUV, waveglider) Barrow NRL aircraft range In the fall of 2015, a 6 week experiment will be conducted to measure physical processes at the airiceocean boundary, using in situ and remote sensing techniques (Figure 5). The central placorm with be the R/V Sikuliaq, which will transit north to the ice edge on Oct 1, and follow the advancing ice south (Figure 6). 10 3 10 4 10 5 10 6 10 7 10 8 10 −4 10 −3 10 −2 10 −1 10 0 10 1 10 2 Fetch (scaled), g x / U 2 Wave energy (scaled), g 2 (H/4) 2 / U 4 ← P−M limit ice sea swell The central hypothesis of the ‘Sea State’ DRI is that surface waves now have a much greater role in the contemporary Arc&c Ocean (e.g., Figure 1) and the dynamics of the seasonal ice zone. There is the poten&al for a feedback, as wave genera&on is controlled by the amount of open water fetch (Figure 2). At smaller scales, waves and ice interact to aRenuate and scaRer the waves while simultaneously fracturing ice into ever changing floe sizes. The changing seasonal ice zone presents new opportuni&es and new problems. Naviga&on and other mari&me ac&vi&es become possible, but waves, storm surges, airsea fluxes and coastal erosion will likely increase. 2002-2014 mean: yd 299 (Oct 26) 1989-2001 mean: yd 278 (Oct 5) 1979-1988 mean: yd 266 (Sep 23) Thomson & Rogers, 2014, GRL Figure 1. WAVEWATCH 3 model hindcast of waves during a storm in Sept 2012. The storm coincided with the minimal ice extent on record. Figure 2. Measured wave energy and open water distance, scaled by wind speed, during the open water season of 2012. The DRI will focus on arc&c condi&ons during the late summer and early autumn, especially the freezeup of the Beaufort and Chukchi seas, to capture the strongest storms and maximum open water. The fall ice advance now occurs much later than in previous decades (Figure 3). To understand the implica&ons of this shii, the WAVEWATCH3 model has recently been upgraded with several different ice algorithms. These can be applied in a hindcast (e.g. Figure 4) or forecast mode to quan&fy the related changes in the wave climate. Results suggest that stronger wave energy flux events have occurred in recent years. Figure 3. Date of seasonal transiIon, when ice begins to advance in the ChukchiBeaufort Sea, by year. Data from NSIDC. Figure 4. Daily Ime series of wave energy arriving at ice edge for a selecIon of recent years. Results from WAVEWATCH 3. Figure 6. Cruise track for the R/V Sikuliaq during the fall 2015 field campaign. Figure 5. SchemaIc of the fall 2015 field campaign. Stammerjohn et al., 2012; GRL, updated
