Fig. 5
From: Investigation of dominant traveling 10-day wave components using long-term MERRA-2 database
Latitude–altitude sections of the potential vorticity gradient (the top row), the refractive index squared (the middle row) and the divergence of the EP flux (the bottom row) for E1 wave over September 11–30 (the first column), and E2 wave over June 2–21 (the second column) in 2013, respectively. Regions with negative refractive index squared are shaded in red, while regions with negative potential vorticity gradient and regions with significant EP flux divergence or convergence are represented by colored contours. The black contours denote EPX (the top row), EPZ (the middle row), and the zonal wind amplitudes (the bottom row) of these two 10-day waves. Solid and dotted black contours denote the northward and southward directions for EPX in the top row, and the upward and downward directions for EPZ in the second row