GEOSCAN, résultats de la recherche


TitreModeling Arctic storm waves by SWAN in the southern Beaufort Sea
AuteurHoque, M A; Solomon, S M; Perrie, W; Toulany, B; Mulligan, R
SourceArctic change 2008, conference programme and abstracts/Arctic change 2008, programme et résumés de la conférence; 2008 p. 92-93
Séries alt.Secteur des sciences de la Terre, Contribution externe 20080415
RéunionArctic Change; Quebec City; CA; décembre 9-12, 2008
ProvinceRégion extracotière du nord
Sujetsanalyse environnementales; etudes de l'environnement; effets sur l'environnement; milieux marins; tempêtes; dépôts de tempête; etudes des ondes de surface; modèles; établissement de modèles; changement climatique; géologie de l'environnement; géologie marine; Nature et environnement
Résumé(disponible en anglais seulement)
Predicted changes in the global climate are expected to be most severe at high latitudes. Arctic climate changes will likely involve greater ice-free extent and duration and potentially increasing storm activity. These changes will lead to increasing wave energy in the southern Beaufort Sea. As interest in the oil and gas resources in the regions grows, forecasting and hindcasting of wave conditions becomes increasingly important for industrial and community development as well as for examination of the safety and vulnerability of existing structures and sites of cultural importance. In this study the wave model SWAN (Simulating Waves Nearshore) is implemented for wave hindcasting in the southern Beaufort Sea. SWAN, a third generation spectral wave model, is widely used for computation of wave fields in shelf seas, coastal areas and lakes. The model represents wave generation, propagation and dissipation by whitecapping, bottom friction and depth-induced breaking.

SWAN is implemented in non-stationary mode over two nested grids. The coarse resolution (0.15x0.05) domain is bounded by longitudes 142.5W and 126W, and latitude 71.75N. The fine resolution (0.015x0.01) domain that covers the Mackenzie Delta and adjacent coastal waters is bounded by longitudes 138W and 133.05W, and latitude 69.85N. Wind fields are from the Meteorological Service of Canada Beaufort (MSCB) wind reanalysis, which produced an hourly wind hindcast for the period 1985-2005 at 3442 grid points over the coarse grid computational domain. ETOPO2 bathymetry is used for coarse grid hindcasting. For the nested region, a fine resolution (0.015oX0.005o) bathymetry is generated based primarily on data from Canadian Hydrographic Service charts and field sheets. Measured water level at Tuktoyaktuk is used as model input for storm surge. The ice cover information from the Canadian Ice Service is used to incorporate the moving boundary of the ice edge during storms. Computational grid points with greater than 50% ice are considered as land points with no wave generation or propagation.

Eight storms during the MSCB wind hindcasting period are studied. Five storms (1985, 1986, 1987, 1991 and 2004) are selected for model verification based on the available wave measurements. Model results are compared with observations using time series of wave parameters, spectral distributions as well as statistical analysis; and are found to be in good agreement. After validation of the model, four severe Arctic storms (1985, 1993, 1999 and 2000) are studied to evaluate wave conditions in the Mackenzie Delta and adjacent coastal waters. Severe waves are predominantly from the northwest direction. Fully developed seas in the northwestern quadrant of the nested region, reached wave height and peak period of 6.1 m and 10 s respectively in 1999; and 2.76 m and 6.7 s in 2000. Although the storm intensities are similar during 1999 and 2000 storms, waves are substantially higher in 1999 because of the large ice-free fetch in the western Arctic Ocean. The model can be used in future for operational wave forecasting as well as for studying the impacts of severe Arctic storms and climate change on coastal processes in the southern Beaufort Sea.