Pacific Summer Water at Stations on the Chukchi Sea northern slope

Figure 3 shows the time-series variation of water temperature observed at station HSN/NHC on the Chukchi Sea northern slope. At this station, water masses classified as Pacific Summer Water were observed from July to March (colored areas in Figure 3). The mean sub-surface (30-60 m) temperatures of the water mass containing a large amount of Pacific summer water were 0.0°C in Period 1 (2003-2005) and 0.3°C in Period 2 (2015-2019) for the period indicated by the colored area. The current direction at the same station was northwestward throughout the year, and the mean sub-surface current velocity (northwestward: positive) during the coloring period was 15.4 cm s^-1 in period 1 and 20.9 cm s^-1 in period 2. It suggests that the Pacific summer water at station HSN/NHC on the Chukchi Sea northern slope is transported in a northwestward direction by the Chukchi Slope Current (Figure 4).

Figure 3: Time series variation of HSN/NHC water temperatures at stations

期間： Period　　水温： Water Tempereture

Figure 4. Northwestward (red) time series variation of current velocity (sea level - 150 m)

深さ： Depth　　南東方向： Southeastward　　北西方向： Northwestward