A Case Study of the Near-Neutral Coastal Internal Boundary-Layer Growth: Aircraft Measurements Compared with Different Model Estimates

A simplified version of a model of the internalboundary layer evolution is compared with aircraftmeasurements across the southern part of the east coast ofSweden (Blekinge). The two flight occasions used hererepresent relatively high wind velocities and negligiblesurface heat flux. Both the vertical potential temperaturegradient and the surface temperaturedifference between land and sea are small. Modelpredictions of the internal boundary-layer (IBL)height agree well with data, for both short and largerdistances from the coastline. The contributions to theIBL growth from the mechanical turbulence and theZilitinkevich correction are discussed, as are thesensitivities of the growth to a number of physicalparameters. In near neutralconditions, the vertical potential temperaturegradient is found to be an important parameter for thegrowth of the IBL.A comparison with several simple model estimates forthe height of the IBL is presented. The majority ofthe models overestimate the IBL height. Some of themodels give reasonable results close to the coast, butgenerally the simple models perform less well atlarger distances.