Hydrological processes interconnecting the two largest watersheds of South America from multi‐decadal to inter‐annual time scales: A critical review

Abstract

The hydrological aspects of the Amazon and the La Plata basins are interconnected through southward moisture transport performed by the Low‐Level Jet east of the Andes and the South Atlantic Convergence Zone. Remote effects of sea surface temperature variability in the Pacific and the Atlantic are of varied periodicities, from multi‐decadal to inter‐annual time scales. Major oscillations thus far detected are Atlantic Multi‐decadal Oscillation, Pacific Multi‐decadal Oscillation, North Atlantic Oscillation, Atlantic Dipole, Antarctic Oscillation, and the El Niño Southern Oscillation. In the multi‐decadal, inter‐decadal and decadal time scales, the effects of climate variability over the hydrological processes that interconnect the Amazon and La Plata watersheds are felt predominantly in the South American Monsoon season, while on the inter‐annual scale the effects vary along the year. The hydrological memory in Amazonian soils is also responsible for the inter‐annual variability of hydrology of the Amazon Basin. Due to the effects of soil water on evapotranspiration, the hydrological memory can affect the supply of moisture to the La Plata Basin, influencing the inter‐annual variability of this basin. The implications of the observed oscillations to the hydrological and climatological variability in the two basins are discussed and synthesized in this article. Hypotheses for future research are formulated.

A multivariate assessment of climate change projections over South America using the fifth phase of the Coupled Model Intercomparison Project

“…(2019). Precipitation in SESA is also influenced by moisture in the Amazon basin that is transported by the South American low‐level jet (Marengo et al ., 2002; Junquas et al ., 2012; Zanin and Satyamurty, 2020). Previous studies suggest that this increase in rainfall is due to the intensification of the Chaco Low, the South American low‐level jet and the poleward shift of the South Atlantic Subtropical Anticyclone, resulting in an increase in moisture being transported from Amazonia into SESA (Soares and Marengo, 2009; Cabré et al ., 2016).…”

Podocnemis expansa Turtles Hint to a Unifying Explanation for the Evolution of Temperature-Dependent Sex Determination in Long-Lived and Short-Lived Vertebrates

“…Males and females migrate in groups from backwaters, lakes, and small tributaries toward the nesting beaches, sometimes for hundreds of kilometers (sometimes >420 km) as the water levels drop and sandbanks emerge for females to oviposit [Hildebrand et al, 1997;Ferrara et al, 2014]. The exact timing of this migration and oviposition varies by basin and sub-basins Sex Dev 2021;15:23-37 DOI: 10.1159/000515208 throughout P. expansa's distributional range in South America, because hydrological cycles are not uniform, as some depend on local precipitation whereas others depend on regional events that occur a long distance away from the nesting areas [Hildebrand et al, 1997;Vogt, 2008;Zanin and Satyamurty, 2020]. But importantly, the onset of rains and rising water levels in the nesting areas induce hatching, and neonates are guided by vocalizations from adults to join in a mass migration into the flood plains where they feed for an extended period [Hildebrand et al, 1997;Vogt, 2008;Ferrara et al, 2014].…”

Assessment of the RegCM4 Performance in Simulating the Surface Radiation Budget and Hydrologic Balance Variables in South America

“…In the austral summer (DJF), at low levels, near Equator, the RegCM4 simulates very well the easterlies trade winds over the Atlantic ocean. The trade winds are responsible for the advection and transport of water vapor from the Atlantic Ocean to the SA continent (Garreaud et al 2009;Duran-Quesada et al 2009;Zemp et al 2017;Zanin and Satyamurty 2020). The Andes cordillera, located in the west SA, acts as an obstacle to the displacement of trade winds so that there is a shift southward along the east region of the mountains (Montini et al 2019;Zanin and Satyamurty 2020).…”

“…The trade winds are responsible for the advection and transport of water vapor from the Atlantic Ocean to the SA continent (Garreaud et al 2009;Duran-Quesada et al 2009;Zemp et al 2017;Zanin and Satyamurty 2020). The Andes cordillera, located in the west SA, acts as an obstacle to the displacement of trade winds so that there is a shift southward along the east region of the mountains (Montini et al 2019;Zanin and Satyamurty 2020). In the regions of LLJ and northwest Amazon the simulated values are underestimated up to − 4 ms −1 .…”