Mesoscale Climatology and Variation of Surface Winds over the Chukchiâ•fiBeaufort Coastal Areas

The detailed mesoscale climatology of surface winds in the Chukchi–Beaufort Seas and adjacent Arctic Slope region is analyzed using the recently developed Chukchi–Beaufort High-Resolution Atmospheric Reanalysis (CBHAR).Within the study area, surface winds are mainly driven by the prevailing synoptic weather patterns of the Beaufort high andAleutian low and are further modulated by local geographic features through thermodynamic and dynamic processes. Sea breezes, upor downslope winds, and the mountain barrier jets are all clearly captured by CBHAR. Sea breezes emerge in June–September and last most of the day, with a maximum spatial extent 100 km inland and 50 km offshore and maximum speed around 1–3m s in the late afternoon [;1500 Alaska standard time (AKST)]. Thermodynamic impacts ofmountains on the surfacewinds vary from time to time.Drainage flows begin to build at the mountaintop in September and reach the strongest during November–February, occupying the entire slope. Upslope winds demonstrate a clear diurnal cycle during summer, starting to build around 0900 local time, reaching themaximumstrength around 1500 local time and continuing until 2100 local time. Themountain barrier jets (MBJs) are found to bemost active around theChukotkaMountains during cold seasons. Both sea breezes andMBJs are also subject to variations and changes in response to adjusted large-scale atmosphere circulation. Storm activities can inhibit the development of sea breezes.Different responses from theBeaufort high andAleutian low to anomalies in large-scale circulations play a vital role in the variations of MBJ activities over the Chukotka Mountains.