Relationships between pacific and atlantic ocean sea surface temperatures and water levels from satellite altimetry data in the Amazon rivers

• Published in: Revista brasileira de recursos hídricos 2018-01, Vol.23
• Main Authors: Silva, Mylena Vieira, Paris, Adrien, Calmant, Stéphane, Cândido, Luiz Antonio, Silva, Joecila Santos da
• Format: Article
• Language: English
• Subjects: Amazon Basin; Climatic variability; ENGINEERING, ENVIRONMENTAL; ENGINEERING, GEOLOGICAL; ENGINEERING, MARINE; ENGINEERING, OCEAN; Radar altimetry; SST indices
• ISSN: 1414-381X; 2318-0331; 2318-0331
• DOI: 10.1590/2318-0331.231820170148

ABSTRACT The influence of SST (Sea Surface Temperature) of adjacent oceans on the variability of water levels in the Amazon basin was investigated by using radar altimetry from the ENVISAT and Jason-2 missions. Data from the in situ network was used to compare the correlations of water level and SST anomalies in the sub-basins of the Amazonas-Peru, Solimões, Negro and Madeira Rivers. The analysis was made on the monthly and annual scales between 2003 and 2015. The correlations with anomalies of levels from altimetry presented higher accuracy indices than those from the conventional network. In general, ATN and PAC are better correlated with the entire basin. During the flood months, most of the sub-basins presented negative associations with ATN. In the months of ebb, the response to the indexes varies according to the region. The satellite altimetry data permitted to reach regions non-monitored by the conventional network. We also analyzed the impacts of hydrological extremes in all these sub-regions in the last 13 years. In Western Amazon, the drought of 2010 stands out, associated with the warming of the Tropical Atlantic and the El Niño. In the Negro River, the water level anomalies were the lowest in the basin during the 2005 drought. In the Purus River, the effects of the 2010 drought that affected the entire Amazon, were higher in 2011 due to its strong relationship with the Atlântic and Pacific oceans. In general, hydrological extremes are stronger or highlighted when SST increases simultaneously in both oceans. RESUMO A influência da TSM (Temperatura da Superfície do Mar) dos oceanos adjacentes na variabilidade dos níveis de água na bacia Amazônica foi investigada a partir da composição de dados das missões altimétricas ENVISAT e Jason-2. Empregaram-se dados da rede convencional para comparação das correlações de anomalias de níveis de água e anomalias de TSM, considerando as sub-bacias dos rios Amazonas-Peru, Solimões, Negro e Madeira, nas escalas mensal e anual entre 2003 e 2015. As correlações com anomalias de cotas altimétricas apresentaram índices elevados de acurácia em relação àqueles da rede convencional. De modo geral, o ATN e o PAC são mais bem correlacionados com toda a bacia. Durante os meses de enchente, ocorrem associações negativas com ATN para a maioria das sub-bacias estudadas, enquanto, nos meses de vazante, as respostas em relação aos índices variam de acordo com a região. Foram analisadas, também, regiões não monitoradas pela r