Figure 5a shows a BOREAS example of a land-based, warm, and dry turbulent boundary layer that is advected over Candle Lake during strong (8 m s−1) winds. The aircraft intersects a cool, moist, and less turbulent internal boundary layer approximately 8 km downwind from the upwind edge of the lake. The hard flag for the change in variance of the vertical velocity is associated with the aircraft intersection of the internal boundary layer and is physical.
Figure 5b shows outflow from an internal boundary layer over Candle Lake into the mixed forest in BOREAS. The record is hard flagged for the skewness and kurtosis of temperature and the Haar mean and variance of specific humidity. A cool moist lake breeze from Candle Lake (the lake is off the right of the figure) flows 1.5 km from the lake into the mixed forest region at the aircraft altitude