Dynamical Processes of Block Evolution

摘要: The dynamical processes associated with block evolution are investigated by analyzing a GCM run, forced perpetual January conditions. core of the analysis lies on temporal blocks and vorticity budget terms obtained from appropriate compositing procedures 350-mb model output. results examined barotropic experiments, which allow investigation influence an individual process evolution. Results presented for two composite blocks, one close to Atlantic storm track other farther downstream. Although these found develop differently, they share following characteristics. During decay linear dominate, high- low-frequency eddy fluxes contribute equally toward prolonging lifetime 2 3 days. While time average yields that consistent previous diagnostic studies, it is shown such approach exaggerates role played high-frequency eddies. experiments show nonlinear self-interaction anomaly plays minimal in It remaining part flux contributes significantly evolution, indicating case-to-case variability blocking events can be substantial, nonlinearity slowly moving, nonsteady component flow important events. also demonstrate effect divergence crucial correctly reproducing structure high. implications results, as apply some prominent theories, discussed.