Impacts of teleconnection patterns on South America climate

Abstract

Oceanic heat sources disturb the atmosphere, which, to come back to its initial state, disperses waves. These waves affect the climate in remote regions, characterizing the teleconnection patterns. In this study, we describe eight teleconnection patterns that affect South America climate: the El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO), the Tropical Atlantic Dipole (TAD), the South Atlantic Dipole (SAD), the Southern Annular Mode (SAM), the Madden-Julian Oscillation (MJO), and the Indian Ocean Dipole (IOD). Precipitation and winds at 850-hPa anomalies, considering these teleconnection patterns in ENSO neutral periods, are also presented. Overall, southeastern South America and the north sector of the North and Northeast regions of Brazil are the most affected areas by the teleconnection patterns. In general, there is a precipitation dipole pattern between these regions during each teleconnection pattern.

Drought Assessment in São Francisco River Basin, Brazil: Characterization through SPI and Associated Anomalous Climate Patterns

“…This anomalous high pressure seemed to enhance the flow of the low-level jet east of the Andes towards Southeastern South America (Figure 6), then favored shaping a precipitation dipole between the south and SEB. In this dipole, the lack of rain in the region of the SACZ is associated with above-average precipitation in the southern region of the country or vice-versa [41,45,92,93]. These anomalous precipitation and low-level circulation patterns were also similar to the ones registered in the energy crisis in 2001 [91].…”

“…Variations in atmospheric circulation patterns in the NEB and SEB may directly affect the availability of water in the SFRB [25,41]. Usually, droughts in the NEB are mainly associated with (a) the occurrence of the warm phase of the El Niño Southern Oscillation (ENSO) phenomenon, resulting from an anomalous warming of the surface of the Tropical Pacific sea, which causes changes in the Walker zonal circulation cell, negatively impacting precipitation in the NEB [42][43][44][45] and (b) part of the rainfall variability is explained by warming in the North Tropical Atlantic Ocean, which results in an anomalous position further north of the Intertropical Convergence Zone (ITCZ) compared to its climatological position [45][46][47][48][49][50][51]. The SEB is located in the transition region of the tropical and extratropical atmospheric regimes and presents complex drought mechanisms, which affect weather patterns and, consequently, the rainfall [52].…”

The heat wave of October 2020 in central South America

“…It is possible that the October 2020 heat wave could be related to remote forcing, probably associated with oceanic heat sources that area capable of disturbing the atmosphere (Reboita et al ., 2021). To verify this possibility, we construct composites considering the period of September 23 to October 15 using some meteorological variables (Figure 6).…”

Evolution of Physical and Biological Patterns Along the Tropical and South Atlantic Western Boundary: A Satellite Perspective

“…Since the correlations for different isobaths were very similar, we chose to show just the results for −200 m isobath. We chose the Niño 3.4 to represent the El Niño Southern Oscillation index because the others (Niño 1.2, 3, and 4) showed relatively similar correlations and the Niño 3.4 better represents its impact in the study region (Bruick et al., 2019; Reboita et al., 2021; Rodrigues et al., 2015).…”

“…Several studies have investigated the influence of Pacific climate indices in the South Atlantic Ocean. For PDO and El Niño, the mechanism that explains this connection is the propagation of extratropical atmospheric Rossby waves (Cai et al., 2020; Grimm, 2003; Lopez et al., 2016; Reboita et al., 2021; Rodrigues et al., 2015). However, these are mechanisms at a large scale, and they modify the ocean primarily through local modification of the winds.…”