Observations of Sea-land Breeze Circulation in Surface Wind Time Series

The Korean peninsula is about 1,100 km long in the south-north direction, and 300 km wide in the west-east direction. Just about 10 km away along the east coast, the peaks of the Taebaek mountain range, which are about 1500 m high, are located. Thus, in general, the terrain slope to the west side of the range is smooth but the slope to the east side is very steep. In the east coastal area, in addition to the land-sea boundary, the steep terrain also plays as strong mesoscale surface forcing. In order to identify sea-land breeze circulations over such complex terrain, we analyze the time series at several surface weather stations along the east coast. Using the multi-resolution (MR) technique, we composite the ensemble-averaged signals on the timescales between 1-24 hour(s). The analysis results are compared between summer and winter. In general, the mesoscale, west-east wind components (U_m) are significantly stronger than the south-north components (V_m), which is more obvious during summer. Considering the intensified contrast of sea versus land surface temperatures and then the enhanced sea-land breeze circulations during summer, the result does make sense. But the specifics of the ensemble-averaged U_m and V_m fields vary depending on the coastal line shape. Also, we will present the detailed analysis method and key statistics of the ensemble-averaged mesoscale wind fields.