Inhaltszusammenfassung

Two detailed case studies of summertime coastal meso-scale cyclones (MCs) over the Weddell Sea are presented using aircraft, satellite and conventional data. Aircraft measurements were part of a mesocyclone experiment performed during the Antarctic summer season 1989/90. The MCs investigated by the aircraft missions had scales of about 200-300 km, lifetimes around 12 h and developed as vortices with shallow vertical extent (about 2 km) in conditions of low-level off-ice flow. Climatological s...Two detailed case studies of summertime coastal meso-scale cyclones (MCs) over the Weddell Sea are presented using aircraft, satellite and conventional data. Aircraft measurements were part of a mesocyclone experiment performed during the Antarctic summer season 1989/90. The MCs investigated by the aircraft missions had scales of about 200-300 km, lifetimes around 12 h and developed as vortices with shallow vertical extent (about 2 km) in conditions of low-level off-ice flow. Climatological studies show that the majority of the observed summertime MCs reveal similar characteristics and are found most frequently along the coast of the eastern Weddell Sea. The case studies suggest a connection to orographic forcing for the meso¬cyclo¬genesis and the three-dimensional structure of the MCs. In one of the cases low-level wind speeds of about 15 m/s associated with zones of strong wind shear and frontal character were detected and were attributed to channeled katabatic outflow. Turbulent fluxes at the surface reach only small amounts and the thermodynamical forcing by their vertical convergence is considered unimportant.» weiterlesen» einklappen

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DDC Sachgruppe:
Naturwissenschaften