Keywords: Marine Atmospheric Boundary Layer, MABL, Richardson number, HIRLAM, Baltic Sea, radiosonde measurements, vertical profiles of meteorological elements, meteorological experiments, EC-FP5, PEP-in-BALTEX
Marine atmospheric boundary-layer height estimated from NWP model output
The application of the bulk Richardson number approach to determine the height of the marine atmospheric boundary layer from standard output of Numerical Weather Prediction models is discussed. It is argued that over smooth surfaces like the sea, the critical Richardson number can be expected to be smaller than over land. Based on 4 days of intensive measurements of the height of the marine atmospheric boundary layer over a small island in the Baltic Sea and a Richardson analysis on simultaneous output from the HIRLAM model, the critical Richardson number for the marine atmospheric boundary layer was found to be around 0.05. Use of the generally accepted value of 0.25 resulted in a clear overestimation of the height of boundary layer over the sea.