In a position active unfavorable transition transition unfavorable active unfavorable unfavorable unfavorable active active transition transition active Source of Identification (Z)-Semaxanib custom synthesis Herdies et al. [45] Herdies et al. [45] CPTEC/INPE Rosa et al. [44] Rosa et al. [44] Rosa et al. [44] CPTEC/INPE Rosa et al. [44] Quadro et al. [36] CPTEC/INPE CPTEC/INPE Rosa et al. [44] CPTEC/INPE Rosa et al. [44] CPTEC/INPE CPTEC/INPE CPTEC/INPEMost on the events in 1999 to 2018 represent the classical formation from the SACZ discovered inside the literature, like in Herdies et al. [45] and Quadro et al. [36]. SACZ events had been organized from the MJO influence phase and in related quantities. With the total events,Atmosphere 2021, 12,5 ofmost occurred in the course of the active Alvelestat site phases (7), followed by unfavorable (6) and transition phases (four). two.4. Methodology To relate the SACZ events towards the phases on the Madden ulian Oscillation (MJO), the real-time multivariate index (RMM) defined by Wheeler and Hendon [46] and information readily available from the Bureau of Meteorological Study Center (BMRC) had been made use of. As outlined by many research [17,479], the indexes that contribute to convective activity in SA are phases 1, 2, 7, and 8; therefore, within this study, they may be referred as “the active phase with the MJO”. Similarly, the unfavorable phases will be the “unfavorable phase of your MJO” (0 and from 3 to 6) along with the “transition phase MJO”, indicating when SACZ occurs among the unfavorable phase as well as the active phase with the MJO. As a result, it was probable to confirm the influence of MJO on the development in the SACZ, even in the unfavorable phases, for the occurrence of convection in summer season in SA. To confirm the dynamic behavior of meteorological variables in relation to the unique phases with the MJO and thus highlight the principle traits, quite a few composites had been constructed: three days ahead of (-3D), during (the average period of days for every single SACZ event (0D) (Table 1)), and two days later (2D) for the occurrence with the convergence zone. For instance, within the SACZ event that occurred amongst 11 December and 21 December 2008, day 0D is definitely the typical of this 11 day period, while days -3D and 2D refer to days eight and 23 December 2008, respectively. 3. Benefits The main characteristics of the upper, medium, and reduce levels with the tropospheric circulation more than tropical SA during the active, unfavorable, and transition phases of MJO are described in this section. 3.1. Dynamic Circulation with the Meteorological Variables just before, throughout, and following the SACZ three.1.1. Composites of the Active Phase of MJO Upper level (250 hPa) The composites in the days prior (Figure 2a) towards the formation in the SACZ shows the predominant presence of BH involving ten and 20 S in addition to a TNB together with the linked vortex more than the AO–standard circulation located inside the southern hemisphere throughout the summer season [50]. The regions with optimistic horizontal divergence values were positioned more than the northern and northeastern components of Brazil, where there have been flow difluence locations. Throughout the SACZ days (0D, Figure 2b), the BH lengthened zonally, plus the TNB shifted north from its preceding position. Areas of constructive horizontal divergence lowered in intensity (9 10-5 s-1 ). It is clearly shown that these locations of divergence represent the low-level convergence band, oriented inside the northwest outheast path, which can be classic with the SACZ. In Figure 2c, following the SACZ event (2D), the center on the BH moves to the west, as well as the alignment of the wind divergence band becom.