Fig. 9

a Vertical profiles of the climatology of zonal wind (red line; unit: m s⁻¹) and the regression of detrended vorticity advection \(- \overline{u}\left( {\partial \zeta^{\prime} / \partial x} \right)\) (black line; unit: 10^–12 s⁻²) and zonal vorticity gradient \(\partial \zeta^{\prime} / \partial x\) (blue line; unit: 10^–13 m⁻¹ s⁻¹) onto the detrended SPEI-3 over SE China. b is same as a, but for the climatology of meridional temperature gradient \(\partial \overline{T}/\partial y\) (red line; unit: 10^–7 m⁻¹ s⁻¹) and the regressed meridional temperature advection \(- v^{\prime}\left( {\partial \overline{T}/\partial y} \right)\) (black line; unit: 10^–7 s⁻²) and the regressed meridional wind \(v^{\prime}\) (blue line; unit: 10^–2 m s⁻¹). Dots indicate significant values exceed the 0.1 significance level. c Regression of detrended horizontal wind (vectors; unit:m⁻¹ s⁻¹) onto the detrended SPEI-3 over SE China and the climatology of zonal wind (shading; unit:m⁻¹ s⁻¹) at 200 hPa. d is same as c, but at 700 hPa. Significant zonal wind or meridional wind exceeding the 0.1 and 0.05 significance levels are marked by green and black vectors, respectively. The Tibetan Plateau region with elevations exceeding 3000 m is shaded gray