Q2.7: Rossby wave group velocity Same setting as in Q.2.6, in Columbus, OH, for barotropic Rossby wave in the dispersion relationship (2.2.5) @ = Uk - k K Calculate the zonal group speed cgx = dw/dk for a planetary wave (wave number one) k = 1277, and for a synoptic wave (wave number six) k = 6- in the cases of L a) Mean flow U = 0 b) Mean flow U = 20 m/s c) Compare the group velocity with the phase speed obtained in Q2.5 and discuss.