Do the recent severe droughts in the Amazonia have the same period of length?

Abstract

We propose a new measure based on drought period length to assess the temporal difference between the recent two severe droughts of 2005 and 2010 in the Amazonia. The sensitivity of the measure is demonstrated by disclosing the distinct spatial responding mechanisms of the Northeastern and Southwestern Amazon (NA, SA) to the surrounding sea surface temperature (SST) variabilities. The Pacific and Atlantic oceans have different roles on the precipitation patterns in Amazonia. More specifically, the very dry periods in the NA are influenced by El Niño events, while the very dry periods in the SA are affected by the anomalously warming of the SST in the North Atlantic. We show convincingly that the drought 2005 hit SA, which is caused by the North Atlantic only. There are two phases in the drought 2010: (i) it was started in the NA in August 2009 affected by the El Niño event, and (ii) later shifted the center of action to SA resulted from anomalously high SST in North Atlantic, which further intensifies the impacts on the spatial coverage.

Changes in Climate and Land Use Over the Amazon Region: Current and Future Variability and Trends

“…Recent extreme climatic events in the region, such as droughts and floods, changes in the rainy and dry seasons, increased fire risk with associated their impacts on climate, health, and biodiversity are examples of what could happen in Amazonia as a consequence of climate change (Espinoza et al, 2011(Espinoza et al, , 2012aJiménez-Muñoz et al, 2013, 2016Gatti et al, 2014;Duffy et al, 2015;Erfanian et al, 2017;Aragão et al, 2018). Three "megadroughts" in 2005(Jiménez-Muñoz et al, 2016Marengo and Espinoza, 2016;Zou et al, 2016) were events classified at the time of their occurrence as "one-in-100 year event". Past mega-droughts were registered in 1925-1926, 1982-1983due to El Niño (Tomasella et al, 2011Marengo and Espinoza, 2016).…”

Impacts of the Pacific Meridional Mode on June–August precipitation in the Amazon River Basin

“…Espinoza et al, 2011Espinoza et al, , 2013Casimiro et al, 2013). The northeastern Amazon precipitation is largely modulated by ENSO, and the southwestern part by the Atlantic SST (Aceituno, 1988;Tedeschi et al, 2013;Satyamurty et al, 2013a;Zou et al, 2016). However, the correlation between precipitation in the equatorial western Amazon and the Pacific and Atlantic SST is relatively weak (Enfield, 1996).…”

Century‐scale causal relationships between global dry/wet conditions and the state of the Pacific and Atlantic Oceans

“…For instance, the El Niño-Southern Oscillation (ENSO) is an atmosphere-ocean coupled mode of climate variability in the tropical Pacific [Hoerling et al, 1997;McCabe and Dettinger, 1999;Yuan et al, 2015]. Zou et al [2015] showed that sea surface temperature variabilities in the tropical Pacific and Atlantic Oceans are of great importance in forming the climate conditions that drive interannual rainfall variations over the Amazon. In recent years, climate signals from the oceans, such as the ENSO, the North Atlantic Oscillation (NAO), and the Pacific Decadal Oscillation (PDO), have been treated as a source of climate predictability in dynamical forecasting for global and regional dry and wet conditions, because the oceans possess a large heat capacity and can act as a long-term memory for the climate system [Cayan et al, 1998;Barlow et al, 2001].…”