Summer marine fog distribution in the Chukchi–Beaufort Seas

We study the spatial and temporal variability of summer marine fog in the Chukchi–Beaufort region (175°E–150°W, 70°N–86°N) using the in-situ visibility measurements aboard the Chinese research fleet Xuelong (I and II) and a fog product we derive using the Vertical Feature Mask product of the spaceborne CALIPSO observations. The Xuelong in-situ observations show that the fog frequency in the Chukchi–Beaufort region has a maximum of ~18% in the early morning and is less than 10% in the rest of the day. The latitudinal distribution of the Xuelong-based in-situ fog frequency further shows high fog occurrences at 74°N and 79°N, which are related to the local high fog occurrences near 72°N–74°N and 76°N–80°N in the central Chukchi–Beaufort region, as revealed by the longitude-latitude pattern of the CALIPSO-based spaceborne fog frequency distribution. The CALIPSO-based fog frequency is also shown to be lower along the continental coastlines than in the Chukchi–Beaufort region. This longitude-latitude distribution may be explained by a reduced fog formation due to the Pacific warm current flowing into the Arctic region through the Bering Strait in the summer as well as an enhanced fog formation in the Chukchi–Beaufort region when the southward flow of the Beaufort Gyre interacts with the Pacific warm current.