Episódios de bloqueios no hemisfério Sul: comparação entre reanalises do NCEP/NCAR e modelo HadCM3

Damião M.C.M., Cavalcanti I.F.A., Trigo R.M., DaCamara C.C., Aragão M.R.S.
Revista Brasileira de Meteorologia, 24, 3, 262-275

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A comparison of blocking episodes for the Southern Hemisphere obtained from the Hadley Centre (HadCM3) model results and from NCEP/NCAR reanalysis for the period from 1960 to 2000, is discussed in this study. The definition of blocking is obtained by using an objective index based on two, 500 hPa geopotential height, meridional gradients. The seasonal cycle and preferential areas of occurrence are well reproduced by the model. Similar to the reanalysis results, the South Pacific and Oceania were the preferred regions of blocking occurrence. The frequency of blocking episodes simulated by the model was also similar to the observed, with higher blocking occurrences in the winter and beginning of spring (from June to September).