Open AccessCalculated wind climatology of the South-Saxonian/North-Czech mountain topography including improved resolution of mountains
Author(s) -
D. Hinneburg,
G. Tetzlaff
Publication year - 1996
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-996-0767-2
Subject(s) - geostrophic wind , radiosonde , mesoscale meteorology , geology , wind speed , climatology , meteorology , stratification (seeds) , wind direction , prevailing winds , atmospheric sciences , geodesy , geography , seed dormancy , botany , germination , dormancy , biology
A mesoscale model has been applied tocalculate climatological means of the surface wind. A reliable average requiresmore than 40 model runs, which are differentiated by the direction and speed ofthe geostrophic wind under the assumption of neutral stratification. Thefrequency distributions of the geostrophic wind have been taken fromobservations of the 850-hPa winds at the radiosonde station in Prague for a10-year period. The simulation results have been averaged over all sectors andspeed classes of the geostrophic wind according to their frequencies. Acomparison of the calculated mean wind speeds with observed ones showsdeviations of about 0.4 ms–1 outside the mountains. Therepresentation of steep topography and isolated mountains on the basis of a 3-kmhorizontal resolution of the simulations needs special treatment in order toreduce the gap of up to 4 ms–1 between observed and simulated meanwind speeds over mountains. Therefore, an empiric speed-up formula has beenapplied to the isolated mountains that otherwise would fall through the 3-kmmeshes. The corresponding deviations have been reduced to 1.5 ms–1