Fig. 5: Persistence of NTA SSTA and its effects on the JJA convection in Cerrado.

a Composite of seasonal evolution of the NTA index. Individual years with positive NTA are displayed by thin pink lines, with their ensemble mean shown by a thick line. Dots indicate statistically significant results based on a bootstrap test (N = 5000). Similarly, negative NTA years are displayed in blue color. b, c Composite patterns related to the atmospheric convective activity for the JJA season in positive NTA years (pNTA). b Latitude-pressure cross-section (over 60°W-40°W) illustrating atmospheric meridional overturning circulation (MOC) by vectors. The x- and y-components of vectors correspond to atmospheric northward (‘v’, in m s^-1) and vertical (‘\(\omega\)’, in Pa s^-1) wind, respectively (obtained from ERA5). Originally, positive ω means a downward motion, but for visual clarity, it was rescaled and reversed by multiplying −100 so that positive indicates an upward motion. The gray bar at the bottom denotes the latitudinal range of Cerrado (darker color for northern Cerrado). c NOAA outgoing longwave radiation (in W m^-2). d, e Same as (b, c) but for negative NTA years (nNTA). Statistically significant results identified from bootstrapping (N = 5000) are highlighted by colored arrows (blue for ascent, orange for descent) and hatches, respectively.