Mamani Leonardo, Andreoli Rita V, de Souza Itamara Parente, Cevalho Wallace, Sales Djanir, Kayano Mary Toshie, de Souza Rodrigo Augusto F, Molina-Carpio Jorge, Ceron Wilmar L, Macedo Tabata
Programa de Pós-Graduação em Clima e Ambiente, Instituto Nacional de Pesquisas da Amazônia, Universidade do Estado do Amazonas, Av. André Araújo, 2936, Bairro Aleixo, 69060-001 Manaus, AM, Brazil.
Programa de Pós-Graduação em Clima e Ambiente, Instituto Nacional de Pesquisas da Amazônia, Universidade do Estado do Amazonas, Av. André Araújo, 2936, Bairro Aleixo, 69060-001 Manaus, AM, Brazil; Escola Superior de Tecnologia, Universidade do Estado do Amazonas, Av. Darcy Vargas, 1200, Parque 10 de Novembro, 69065-020 Manaus, AM, Brazil.
Sci Total Environ. 2025 Feb 1;963:178536. doi: 10.1016/j.scitotenv.2025.178536. Epub 2025 Jan 17.
The teleconnections between El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and Tropical North Atlantic warming (+TNA) play a critical role in characterizing extreme drought events in the Amazon Basin (AB). This study examines the seven most recent drought extreme events up to 2023, using seasonal composites of the sea surface temperature and atmospheric variables over a five-quarter period starting at the austral spring(-1) of the year preceding that when the lowest water level at Manaus port was recorded. Two distinct patterns emerge, driven by consecutive ENSO events with opposite phases, referred to as cyclic La Niña-El Niño and cyclic El Niño-La Niña drought events. For these events, IOD and ENSO modes are coupled in the same phase during the springs, with ENSO triggering and enhancing IOD, and the IOD, in turn, enhancing and sustaining ENSO through Walker circulation. This interaction can amplify extratropical Rossby waves in both hemispheres, originating from the equatorial Indian and Pacific Oceans. Notably, strong positive ENSO and IOD phases trigger or sustain the +TNA by weakening northeasterlies through a Pacific-North America wave train. The IOD, ENSO and +TNA, individually or combined, influence atmospheric circulation patterns over South America through Rossby waves and anomalous Walker and Hadley circulation patterns, causing dry periods in the AB marked by negative precipitation anomalies across specific regions or the entire AB, consequently modulating the water levels at Manaus. The strong coupling of these three tropical modes is crucial to leading multiyear drought events in the AB. This study underscores the potential for a robust climate forecasting system by monitoring the oceanic indices.
厄尔尼诺-南方涛动（ENSO）、印度洋偶极子（IOD）和热带北大西洋变暖（+TNA）之间的遥相关在表征亚马逊盆地（AB）的极端干旱事件中起着关键作用。本研究考察了截至2023年的最近七次极端干旱事件，使用了从马瑙斯港最低水位记录年份的前一年南半球春季（-1）开始的五个季度期间的海表温度和大气变量的季节合成数据。由具有相反位相的连续ENSO事件驱动，出现了两种不同的模式，分别称为周期性拉尼娜-厄尔尼诺干旱事件和周期性厄尔尼诺-拉尼娜干旱事件。对于这些事件，IOD和ENSO模式在春季处于同一位相耦合，ENSO触发并增强IOD，而IOD又通过沃克环流增强并维持ENSO。这种相互作用可以放大源自赤道印度洋和太平洋的两个半球的温带罗斯贝波。值得注意的是，强烈的正ENSO和IOD位相通过太平洋-北美波列减弱东北风，从而触发或维持+TNA。IOD、ENSO和+TNA单独或共同通过罗斯贝波以及异常的沃克和哈德利环流模式影响南美洲的大气环流模式，导致AB地区出现干旱期，其特征是特定区域或整个AB地区的降水异常为负，从而调节马瑙斯的水位。这三种热带模式的强耦合对于导致AB地区多年干旱事件至关重要。本研究强调了通过监测海洋指数建立强大气候预测系统的潜力。
