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Item type:Publication, The new record of drought and warmth in the Amazon in 2023 related to regional and global climatic features(Nature Research, 2024-12-01)In 2023 Amazonia experienced both historical drought and warm conditions. On October 26th 2023 the water levels at the port of Manaus reached its lowest record since 1902 (12.70 m). In this region, October monthly maximum and minimum temperature anomalies also surpassed previous record values registered in 2015 (+ 3 °C above the normal considering the 1981–2020 average). Here we show that this historical dry and warm situation in Amazonia is associated with two main atmospheric mechanisms: (i) the November 2022–February 2023 southern anomaly of vertical integrated moisture flux (VIMF), related to VIMF divergence and extreme rainfall deficit over southwestern Amazonia, and (ii) the June–August 2023 downward motion over northern Amazonia related to extreme rainfall deficit and warm conditions over this region. Anomalies of both atmospheric mechanisms reached record values during this event. The first mechanism is significantly correlated to negative sea surface temperature (SST) anomalies in the equatorial Pacific (November–February La Niña events). The second mechanism is significantly correlated to positive SST anomalies in the equatorial Pacific, related to the impacts of June–September El Niño on the Walker Circulation. While previous extreme droughts were linked to El Niño (warmer North Tropical Atlantic SST) during the austral summer (winter and spring), the transition from La Niña 2022–23 to El Niño 2023 appears to be a key climatic driver in this record-breaking dry and warm situation, combined to a widespread anomalous warming over the worldwide ocean. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Sedimentary Evolution of a Late Triassic Salt Giant and a Synchronous Carbonate Unit Between the Peruvian Andean Cordillera and the Brazilian Amazonian Foreland(American Association of Petroleum Geologists, 2023-01-01)Salt giants with mixed evaporites/carbonates are sedimentary systems poorly understood in terms of sequence stratigraphy, tectonic control, and related natural resources. To improve the knowledge of these systems, a sedimentology study of a Late Triassic salt giant between the Subandean fold-thrust belt (SFTB) of Peru and the Brazilian Amazonian foreland (AF) was performed on the pre- to postsalt deposits using field observations, thin-section descriptions, and well-log analysis. In addition, this study was compared with sedimentary observations of Upper Triassic carbonate successions from the Subandean-Cordillera transition zone (SCTZ) documented in previous works. This resulted in the following sedimentary events associated to a relative sealevel fluctuation: first transgression, regression, and second transgression. In the SFTB and AF, during the first transgression, continental/transitional siliciclastic environments with sporadic marine incursions allowing the development of salt ponds were formed first. Subsequently, a salt basin surrounded by a mudflat was established. At the end of the first transgression, carbonate deposits dominated. During the subsequent regression, a sulfate platform was established followed by a salt basin enveloped by mudflats and exposed areas. This regression terminated with the development of a central mudflat and an increase of the exposed areas. In the second transgression, carbonates and an eastward mudflat with gypsum ponds dominated the sedimentation. In the SCTZ, external-platform to deep-basin carbonates dominated the sedimentation during the three events. Based on this evolution, eustatic oscillations of the global oceanic level, and structural features published in previous works, it is interpreted that the deposition of the studied salt giant and external carbonates were controlled by thermal sagging and eustatic sea-level oscillations. The available data suggest the existence of a westward migration of the subsidence from the Norian (mid Late Triassic) to the Triassic-Jurassic boundary that may be caused by slab steepening. Hydrocarbon reservoirs and stratabound, sediment-hosted Cu-Ag and Zn-Pb ore deposit occurrences are also partly controlled by the evolution of the mixed evaporite/carbonate sedimentary system in the region between the SCTZ and the AF. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Patterns and Drivers of Evapotranspiration in South American Wetlands(Nature Research, 2023-12-01)Evapotranspiration (ET) is a key process linking surface and atmospheric energy budgets, yet its drivers and patterns across wetlandscapes are poorly understood worldwide. Here we assess the ET dynamics in 12 wetland complexes across South America, revealing major differences under temperate, tropical, and equatorial climates. While net radiation is a dominant driver of ET seasonality in most environments, flooding also contributes strongly to ET in tropical and equatorial wetlands, especially in meeting the evaporative demand. Moreover, significant water losses through wetlands and ET differences between wetlands and uplands occur in temperate, more water-limited environments and in highly flooded areas such as the Pantanal, where slow river flood propagation drives the ET dynamics. Finally, floodplain forests produce the greatest ET in all environments except the Amazon River floodplains, where upland forests sustain high rates year round. Our findings highlight the unique hydrological functioning and ecosystem services provided by wetlands on a continental scale.