scholarly journals Consistency of Long-Term Trends and Closure of the Surface Water Balance in the Amazon River Basin

2021 ◽  
Author(s):  
Daniela Posada Gil ◽  
German Poveda
Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 351
Author(s):  
Franklin Paredes-Trejo ◽  
Humberto Alves Barbosa ◽  
Jason Giovannettone ◽  
T. V. Lakshmi Kumar ◽  
Manoj Kumar Thakur ◽  
...  

The Amazon River Basin (ARB) plays an important role in the hydrological cycle at the regional and global scales. According to the Intergovernmental Panel on Climate Change (IPCC), the incidence and severity of droughts could increase in this basin due to human-induced climate change. Therefore, the assessment of the impacts of extreme droughts in the ARB is of vital importance to develop appropriate drought mitigation strategies. The purpose of this study is to provide a comprehensive characterization of dry spells and extreme drought events in terms of occurrence, persistence, spatial extent, severity, and impacts on streamflow and vegetation in the ARB during the period 1901–2018. The Standardized Precipitation-Evapotranspiration Index (SPEI) at multiple time scales (i.e., 3, 6, and 12 months) was used as a drought index. A weak basin-wide drying trend was observed, but there was no evidence of a trend in extreme drought events in terms of spatial coverage, intensity, and duration for the period 1901–2018. Nevertheless, a progressive transition to drier-than-normal conditions was evident since the 1970s, coinciding with different patterns of coupling between the El Niño/Southern Oscillation (ENSO) phenomenon and the Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and Madden–Julian Oscillation (MJO) as well as an increasing incidence of higher-than-normal surface air temperatures over the basin. Furthermore, a high recurrence of short-term drought events with high level of exposure to long-term drought conditions on the sub-basins Ucayali, Japurá-Caquetá, Jari, Jutaí, Marañón, and Xingu was observed in recent years. These results could be useful to guide social, economic, and water resource policy decision-making processes in the Amazon basin countries.


Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1244
Author(s):  
Victor Hugo da Motta Paca ◽  
Gonzalo Espinoza-Dávalos ◽  
Daniel Moreira ◽  
Georges Comair

The Amazon River Basin is the largest rainforest in the world. Long-term changes in precipitation trends in the basin can affect the continental water balance and the world’s climate. The precipitation trends in the basin are not spatially uniform; estimating these trends only at locations where station data are available has an inherent bias. In the present research, the spatially distributed annual precipitation trends were studied in the Amazon River Basin from the year 1981 to 2017 using the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) product. The precipitation trends were also cross-validated at locations where station data were available. The research also identifies clusters within the basin where trends showed a larger increase (nine clusters) or decrease in precipitation (10 clusters). The overall precipitation trend in the Amazon River Basin over 37 years showed a 2.8 mm/year increase, with a maximum of 45.1 mm/year and minimum of −37.9 mm/year. The highest positive cluster was in Cuzco in the Ucayali River basin, and the lowest negative was in Santa Cruz de la Sierra, in the upstream Madeira River basin. The total volume of the incoming precipitation was 340,885.1 km3, with a withdrawal of −244,337.1 km3. Cross-validation was performed using 98 in situ stations with more than 20 years of recorded data, obtaining an R2 of 0.981, a slope of 1.027, and a root mean square error (RMSE) of 363.6 mm/year. The homogeneous, standardized, and continuous long-term time series provided by CHIRPS is a valuable product for basins with a low-density network of stations such as the Amazon Basin.


2009 ◽  
Vol 10 (4) ◽  
pp. 981-998 ◽  
Author(s):  
Fengge Su ◽  
Dennis P. Lettenmaier

Abstract The Variable Infiltration Capacity (VIC) land surface hydrology model forced by gridded observed precipitation and temperature for the period 1979–99 is used to simulate the land surface water balance of the La Plata basin (LPB). The modeled water balance is evaluated with streamflow observations from the major tributaries of the LPB. The spatiotemporal variability of the water balance terms of the LPB are then evaluated using offline VIC model simulations, the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40), and inferences obtained from a combination of these two. The seasonality and interannual variability of the water balance terms vary across the basin. Over the Uruguay River basin and the entire LPB, precipitation (P) exceeds evapotranspiration (E) and the basins act as a moisture sink. However, the Paraguay River basin acts as a net source of moisture in dry seasons (strong negative P − E). The annual means and monthly time series of ERA-40 P are in good agreement with gauge observations over the entire LPB and its subbasins, except for the Uruguay basin. The E estimates from VIC and inferred from the ERA-40 atmospheric moisture budget are consistent in both seasonal and interannual variations over the entire LPB, but large discrepancies exist between the two E estimates over the subbasins. The long-term mean of atmospheric moisture convergence P − E agrees well with observed runoff R for the upper Paraná River basin, whereas the imbalance is large (28%) for the Uruguay basin—possibly because of its small size. Major problems appear over the Paraguay basin with negative long-term mean of atmospheric moisture convergence P − E, which is not physically realistic. The computed precipitation recycling in the LPB (for L = 500 km) exhibits strong seasonal and spatial variations with ratios of 0%–3% during the cold season and 5%–7% during the warm season.


2008 ◽  
Vol 9 (3) ◽  
pp. 521-534 ◽  
Author(s):  
Clara Draper ◽  
Graham Mills

Abstract The atmospheric water balance over the semiarid Murray–Darling River basin in southeast Australia is analyzed based on a consecutive series of 3- to 24-h NWP forecasts from the Australian Bureau of Meteorology’s Limited Area Prediction System (LAPS). Investigation of the LAPS atmospheric water balance, including comparison of the forecast precipitation to analyzed rain gauge observations, indicates that the LAPS forecasts capture the general qualitative features of the water balance. The key features of the atmospheric water balance over the Murray–Darling Basin are small atmospheric moisture flux divergence (at daily to annual time scales) and extended periods during which the atmospheric water balance terms are largely inactive, with the exception of evaporation, which is consistent and very large in summer. These features present unique challenges for NWP modeling. For example, the small moisture fluxes in the basin can easily be obscured by the systematic errors inherent in all NWP models. For the LAPS model forecasts, there is an unrealistically large evaporation excess over precipitation (associated with a positive bias in evaporation) and unexpected behavior in the moisture flux divergence. Two global reanalysis products (the NCEP Reanalysis I and the 40-yr ECMWF Re-Analysis) also both describe (physically unrealistic) long-term negative surface water budgets over the Murray–Darling Basin, suggesting that the surface water budget cannot be sensibly diagnosed based on output from current NWP models. Despite this shortcoming, numerical models are in general the most appropriate tool for examining the atmospheric water balance over the Murray–Darling Basin, as the atmospheric sounding network in Australia has extremely low coverage.


Gigabyte ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Alexandre Wagner Silva Hilsdorf ◽  
Marcela Uliano-Silva ◽  
Luiz Lehmann Coutinho ◽  
Horácio Montenegro ◽  
Vera Maria Fonseca Almeida-Val ◽  
...  

2021 ◽  
Author(s):  
Suyog Chaudhari ◽  
Erik Brown ◽  
Raul Quispe-Abad ◽  
Emilio Moran ◽  
Norbert Mueller ◽  
...  

<p>Given the ongoing and planned hydropower development projects in the Amazon River basin, appalling losses in biodiversity, river ecology and river connectivity are inevitable. These hydropower projects are proposed to be built in exceptionally endemic sites, setting records in environmental losses by impeding fish movement, altering flood pulse, causing large-scale deforestation, and increasing greenhouse gas emissions. With the burgeoning energy demand combined with the aforementioned negative impacts of conventional hydropower technology, there is an imminent need to re-think the design of hydropower to avoid the potentially catastrophic consequences of large dams. It is certain that the Amazon will undergo some major hydrological changes in the near future because of the compounded effects of climate change and proposed dams, if built with the conventional hydropower technology. In this study, we present a transformative hydropower outlook that integrates low-head hydropower technology (e.g., in-stream turbines) and multiple environmental aspects, such as river ecology and protected areas. We employ a high resolution (~2km) continental scale hydrological model called LEAF-Hydro-Flood (LHF) to assess the in-stream hydropower potential in the Amazon River basin. We particularly focus on quantifying the potential and feasibility of employing instream turbines in the Amazon instead of building large dams. We show that a significant portion of the total energy planned to be generated from conventional hydropower in the Brazilian Amazon could be harnessed using in-stream turbines that utilize kinetic energy of water without requiring storage. Further, we also find that implementing in-stream turbines as an alternative to large storage-based dams could prove economically feasible, since most of the environmental and social costs associated with dams are eliminated. Our results open multiple pathways to achieve sustainable hydropower development in the Amazon to meet the ever-increasing energy demands while minimizing hydrological, social, and ecological impacts. It also provides important insight for sustainable hydropower development in other global regions. The results presented are based on a manuscript under revision for Nature Sustainability.</p>


Sign in / Sign up

Export Citation Format

Share Document