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[MZZ40-P01] Wintertime strong winds off the Bungo Channel, the Kii Channel, and the Ise Bay
Keywords:offshore winds, winter monsoon, cold air, meteorological model
From offshore wind maps, the seas off the Bungo Channel, Kii Channel, and Ise Bay have the largest offshore wind resources in the coastal areas of western Japan. The abundant offshore wind resources mainly reflect the northwesterly monsoon winds prevailing in winter. Cloud images from geostationary meteorological satellites have suggested that these three sea areas serve as routes for cold air to pass through the Japanese archipelago in winter. However, there are few detailed studies on the winds in these three sea areas, and further studies are required to understand the mechanisms of the strong winds and wind conditions that create the abundant offshore wind resources.
In this study, using simulation data from WRF, we analyzed the three-dimensional structure of strong winds that occur in winter in the seas off the Bungo Channel, Kii Channel, and Ise Bay and the outflow paths of cold air, and considered the processes of creating abundant offshore wind resources. The simulation period is from January 28, 2020 to February 3, 2020, when a cold surge occurred. First, from the horizontal distributions of winds, strong winds developed from the west in the order of the Bungo Channel, Kii Channel, and Ise Bay. Maximum wind speed reached 15–18 m/s. In addition, with the development of strong winds, surface temperature decreases and surface pressure increases. This indicates the strong winds are associated with the cold air outflow. From vertical structures of the atmosphere in these three seas, it was found that strong winds are formed near the coast. In addition, the analyses of the movement of the cold air in the lower layer and backward trajectories from the three sea areas shows the main routes of the cold air reaching the Bungo Channel, Kii Channel, and Ise Bay from the Japan Sea.
In this study, using simulation data from WRF, we analyzed the three-dimensional structure of strong winds that occur in winter in the seas off the Bungo Channel, Kii Channel, and Ise Bay and the outflow paths of cold air, and considered the processes of creating abundant offshore wind resources. The simulation period is from January 28, 2020 to February 3, 2020, when a cold surge occurred. First, from the horizontal distributions of winds, strong winds developed from the west in the order of the Bungo Channel, Kii Channel, and Ise Bay. Maximum wind speed reached 15–18 m/s. In addition, with the development of strong winds, surface temperature decreases and surface pressure increases. This indicates the strong winds are associated with the cold air outflow. From vertical structures of the atmosphere in these three seas, it was found that strong winds are formed near the coast. In addition, the analyses of the movement of the cold air in the lower layer and backward trajectories from the three sea areas shows the main routes of the cold air reaching the Bungo Channel, Kii Channel, and Ise Bay from the Japan Sea.