The Extraordinary Equatorial Atlantic Warming in Late 2019

Abstract

From about 2000 onward, variability in the equatorial Atlantic has been relatively low (Prigent et al., 2020; Figure S1 in Supporting Information S1). This quiescent period has been attributed to a weaker Bjerknes feedback and stronger latent heat flux damping (Prigent et al., 2020), the latter being partially associated with the strengthening

Weakening of the Atlantic Niño variability under global warming

“…Furthermore, the models do not reproduce the strong reduction of SST variability in recent decades, simulating a gradual and up to 20 times smaller decrease of the interannual SST variability (Supplementary Table 2). This discrepancy with observations could be caused by internal climate variability or by model error and exists even considering the exceptionally strong 2019 49 and 2021 Atlantic Niño events.…”

Evolution and Prediction of Two Extremely Strong Atlantic Niños in 2019–2021: Impact of Benguela Warming

“…Richter et al. (2022) argued that the warming in late 2019 was the strongest Atlantic Niño event in the satellite era. Given the uniqueness and extremity of the two Atlantic Niños in 2019–2021, it is meaningful to examine how these events occur, whether they were predictable, and how different time‐scale phenomena involve their occurrence.…”

Dual Wave Energy Sources for the Atlantic Niño Events Identified by Wave Energy Flux in Case Studies

“…This fact implies the presence of the waveguide originated from the off‐equatorial region, which is independent to that from the equatorial region. Since the rise of the geopotential in the 1999 summer and the 2019 & 2021 winter is associated with the easterly wind anomaly in the R3 region (Richter et al., 2022), there the waveguide by westward off‐equatorial RWs is hence expected. The energy transported by the waveguide from the off‐equatorial regions may act as the background state during the Niño event.…”

“…This climatic pattern essentially functions via Bjerknes feedback that the zonal wind induced by SST anomaly in turn positively feeds the pattern through equatorial Kelvin waves (KWs), gaining many Niño‐like characteristics as in the Pacific Ocean, hence is referred to as Atlantic Niño (Keenlyside & Latif, 2007; Okumura & Xie, 2006; Zebiak, 1993). However, the increasing number of individual events were reported recently to reveal the diversity of the Atlantic Niño in both timing and intensity that the Niño‐like dynamics is insufficient to explain (Burmeister et al., 2016; Richter et al., 2022).…”

“…This climatic pattern essentially functions via Bjerknes feedback that the zonal wind induced by SST anomaly in turn positively feeds the pattern through equatorial Kelvin waves (KWs), gaining many Niño-like characteristics as in the Pacific Ocean, hence is referred to as Atlantic Niño (Keenlyside & Latif, 2007;Okumura & Xie, 2006;Zebiak, 1993). However, the increasing number of individual events were reported recently to reveal the diversity of the Atlantic Niño in both timing and intensity that the Niño-like dynamics is insufficient to explain (Burmeister et al, 2016;Richter et al, 2022).A typical Atlantic Niño event is nearly phase-locked by the seasonal cycle that develops in boreal spring, peaks in the summer, and dissipates in the fall (Keenlyside & Latif, 2007). Nevertheless, only a fraction of events follows this process, others somehow dissipate slower from the fall or even postpone the peak to the winter (Lübbecke & McPhaden, 2012;Lübbecke et al, 2018;Vallès-Casanova et al, 2020).…”