The Rise of Climate-Driven Sediment Discharge in the Amazonian River Basin

Abstract

The occurrence of hydrological extremes in the Amazon region and the associated sediment loss during rainfall events are key features in the global climate system. Climate extremes alter the sediment and carbon balance but the ecological consequences of such changes are poorly understood in this region. With the aim of examining the interactions between precipitation and landscape-scale controls of sediment export from the Amazon basin, we developed a parsimonious hydro-climatological model on a multi-year series (1997-2014) of sediment discharge data taken at the outlet of Óbidos (Brazil) watershed (the narrowest and swiftest part of the Amazon River). The calibrated model (correlation coefficient equal to 0.84) captured the sediment load variability of an independent dataset from a different watershed (the Magdalena River basin), and performed better than three alternative approaches. Our model captured the interdecadal variability and the long-term patterns of sediment export. In our reconstruction of yearly sediment discharge over 1859-2014, we observed that landscape erosion changes are mostly induced by single storm events, and result from coupled effects of droughts and storms over long time scales. By quantifying temporal variations in the sediment produced by weathering, this analysis enables a new understanding of the linkage between climate forcing and river response, which drives sediment dynamics in the Amazon basin.

Fingerprint of climate change in precipitation aggressiveness across the central Mediterranean (Italian) area

“…Then, for the final selection, the third criterion—|b-1|= min—was additionally involved. Each predictor was repositioned over > 50 iterations until convergence was achieved 99 . The Durbin-Watson statistic was performed to test for auto-correlated residuals because large temporal dependence may induce spurious correlations.…”

Climate Change Impacts on Soil Erosion and Sediment Yield in a Watershed

“…Due to the increasing severity of global warming and climate change effect in recent years, extreme hydrographic phenomena have frequently been observed. Climate change has increased precipitation concentration, volume and intensity, which has significantly impacted runoff and soil erosion in many watersheds [1][2][3]. The sediments generated from watershed erosion are transported to rivers via surface runoff, and they are the main composition of river sediments and a major source of reservoir or river dam sediment deposition [4].…”

Special Issue: 10th Anniversary of Atmosphere: Climatology and Meteorology

“…The second topic area included seven articles [9][10][11][12][13][14][15] and covered a diverse number of phenomena related to extremes and teleconnections that generally operated on subseasonal and seasonal time scales. The sediment discharge in the Amazon Basin [9] was examined and modelled using in situ and satellite derived information in the river sediment discharge for Amazonia (RSDA) model. The study ultimately covered the period from 1859-2015.…”

“…The study ultimately covered the period from 1859-2015. They [9] found an increased sediment discharge across the Amazon basin due to stronger singular rainfall events and/or changes in land cover after 1931. Before that period, wet season rainfall and sedimentation showed interdecadal variability, but little trend.…”

“…After that date, increases in both variables occurred, but more rapidly since the 1990s. While [9] was a longer-term study, [15] was a short-term study (2011-2017) of the interannual variability of the seasonal extent of the North American Monsoon (NAM). The NAM is a period of rainfall in the US southwestern states associated with strong thunderstorm-generated rainfall.…”