Automated Detection Algorithm for SACZ, Oceanic SACZ, and Their Climatological Features

Assessing precipitation extremes (1981–2018) and deep convective activity (2002–2018) in the Amazon region with CHIRPS and AMSU data

“…Positive CDD trends (JJA) and decrease of RX5day, R20mm and SDII through September-May (not shown) in northern Rondônia reflects the regional dynamics of deforestation (Khanna et al, 2017), in which surface roughness decrease in response to deforestation leads to a shift from a thermodynamically driven regime to a dynamically driven one, with convection and precipitation suppression (enhancement) upwind (downwind) of deforested areas. The southeastern portion of the Amazon overlaps with the climatological position of the SACZ, which is responsible for part of rainfall totals in the region mostly during the period of December -March (Kodama, 1992(Kodama, , 1993Carvalho et al, 2004;de Oliveira Vieira et al, 2013;Rosa et al, 2020). A recent study by Zilli et al (2019) showed evidence of a southward displacement of the SACZ and reduced (increased) precipitation at its northern (southern) edge, which could explain the negative PE trends at the SE edge.These negative trends in PE are accompanied by reduction on COV (Fig.…”

“…Near the surface, westward trade winds transport water vapor from the Atlantic through the Amazon basin, with significant water vapour recycling through evapotranspiration along the way (Zemp et al, 2014); these easterlies are then deflected southwards as they approach the Andes mountains, transporting water vapor toward the La Plata Basin and the Andean mountains through a northerly low-level jet (LLJ) (Nogués- Paegle and Mo, 1997;Marengo et al, 2004;Martinez and Dominguez, 2014;. The central and southern parts of the Amazon region are also affected by the South Atlantic Convergence Zone (SACS; Kodama, 1992Kodama, , 1993Carvalho et al, 2004;de Oliveira Vieira et al, 2013;Ambrizzi and Ferraz, 2015;Rosa et al, 2020), which consists of an elongated northwest-southeast oriented axis of clouds and precipitation, with a 10-day half-period of convection, that reaches the South Atlantic subtropics over a stretch of more than 4000 km. The low level convergence and transient moisture transport from the Amazon along its northwestern edge increase both low-level potential temperature and convective instability, and contribute to the maintenance of the SACZ.…”

Dynamic Characteristics of the Circulation and Diurnal Spatial Cycle of Outgoing Longwave Radiation in the Different Phases of the Madden–Julian Oscillation during the Formation of the South Atlantic Convergence Zone

“…These online reports only correspond to the years 1996-2014; therefore, it was necessary to update the events until 2018 using another technical report also provided by the same center. The second mode of recognition was through the study presented by Rosa et al [44], who proposed an objective, simplified, and automatic method to detect SACZ episodes based on satellites measuring OLR and confirming the related cases and adding the newly found cases, resulting in 17 (Table 1), which coincided in the austral summer. Most of the events in 1999 to 2018 represent the classical formation of the SACZ found in the literature, such as in Herdies et al [45] and Quadro et al [36].…”

Regional Climates

“…During the 2019 austral summer, there were six episodes of the South Atlantic Convergence Zone (SACZ; Rosa et al 2020), contributing to exceptionally wet conditions in the second half of January through February across Bolivia and Peru east of the Andes (see Notable events and impacts section). Northern Paraguay had extremely wet conditions in March, receiving over 300% more precipitation than normal.…”