مقايسه ساختار ديناميكي پديده بلاكينگ با مودون ها در شاره هاي ژئوفيزيكي

A case study comparison of the dynamical structure of modons in geophysical fluids with blocking events

In this paper, we attempt to compare the dynamical structure of rnodons, as solutions for the quasi-geostrophic potential vorticity equation in geophysical fluids and blackings. To do this study, a blocking event which was observed in December 2002 and had the same structure with equivalent barotropic modon, was chosen. Then, the relevant synoptic maps in different pressure levels as well as quasi-geostrophic potential vorticity (q) and stream function (\[I) maps in 300 hPa were prepared. The results show the association between the appearance of a low cutoff value of q in quasi-geostrophic potential vorticity maps at 300 hPa level and the intense high anomaly in the 500 hPa geopotential height map. In addition, the scatter diagram of q against ʹlʹ clearly shows the various dynamical features of the blocking in both the blocked and non-blocked regions. Comparison of this diagram and the theoretical modons diagram indicates the similarity between the structure of atmospheric blocking in westerly currents and theoretical modons.