Inhaltszusammenfassung

Three aircraft-based studies of boundary-layer fronts (BLFs) were carried out during the experiment KABEG in April 1997 near the sea-ice edge over the Davis Strait. The zone of strongest cross-front horizontal gradients showed a typical length scale of 20 km, while the along-front scale was observed to be several hundreds of kilometres. The observed BLFs were stronger than the few previously reported cases. Horizontal gradients of potential temperature and specific humidity ranged up to 3 K o...Three aircraft-based studies of boundary-layer fronts (BLFs) were carried out during the experiment KABEG in April 1997 near the sea-ice edge over the Davis Strait. The zone of strongest cross-front horizontal gradients showed a typical length scale of 20 km, while the along-front scale was observed to be several hundreds of kilometres. The observed BLFs were stronger than the few previously reported cases. Horizontal gradients of potential temperature and specific humidity ranged up to 3 K or 0.25 g kg−1 over 20 km, respectively. Low-level winds were around 15 m s−1 parallel to the ice edge. The capping inversion sloped from between 250 and 400 m over sea ice to between 400 and 700 m over ocean. For two BLF cases turbulent fluxes and energy budgets are calculated. Turbulent energy fluxes show a factor 2 to 3 contrast across the ice edge and range from 15 to 50 W m−2 over sea ice and from 50 to 100 W m−2 over open ocean. The mean boundary-layer energy budgets are dominated by cold, dry horizontal advection, which is exceeded by vertical heat flux convergence. The momentum budgets are dominated by pressure gradient force, Coriolis force and momentum flux divergence.» weiterlesen» einklappen

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Klassifikation

DDC Sachgruppe:
Naturwissenschaften