The spatio-temporal variability of groundwater storage in the Amazon River Basin

Abstract

In large Tropical River basins such as the Amazon, groundwater plays a major role in the water and ecological cycles with large influences on the rainforest ecosystems and climate variability. However, due to the lack of monitoring networks, Amazon groundwater storage and its variability remain poorly known. Here, we provide an unprecedented direct estimate of the spatio-temporal variations of the anomaly of groundwater storage over the period January 2003 -September 2010 in the Amazon Basin by decomposing the total terrestrial water storage measured by the Gravity Recovery and Climate Experiment (GRACE) mission into the individual contributions of other hydrological reservoirs, using multi-satellite data for the surface waters and floodplains and models outputs for the soil moisture. We show that the seasonal variations of groundwater storage represent between 20 and 35% of the terrestrial water storage seasonal volume variations of the Amazon. Larger seasonal amplitudes of groundwater storage ( > 450 mm) are found in the Alter do Chão and Iça aquifers in the central part of the Amazon Basin. Anomalies of groundwater storage exhibit a strong interannual variability (STD reaching 120 mm along the central corridor) during the study period in response to hydrologic variability and climatic events such as the extreme drought that occurred in 2005.

The Lake Chad hydrology under current climate change

“…Uncertainties of this study. The decomposition technique employed in the present study to estimate groundwater is commonly used (see the review from Frappart & Ramillien 64 on GRACE and groundwater for instance), and several specific regional studies proved that it is a powerful tool [68][69][70] . Following Frappart et al 69 , the uncertainty on groundwater storage variations can be computed as follows: Based on Ramillien et al 71 , we assumed that σ TWS < 0.015 m over semi-arid area.…”

“…The decomposition technique employed in the present study to estimate groundwater is commonly used (see the review from Frappart & Ramillien 64 on GRACE and groundwater for instance), and several specific regional studies proved that it is a powerful tool [68][69][70] . Following Frappart et al 69 , the uncertainty on groundwater storage variations can be computed as follows: Based on Ramillien et al 71 , we assumed that σ TWS < 0.015 m over semi-arid area. Based on Frappart et al 68 and Papa et al 70 , we assumed that: σ SWS < max(△h)σ Sf lood + max(S f lood )σ h Over Chad Lake, the maximum change of water level from one month to another (max(△h)) is 0.15 m, the maximum surface of the lake during the observation period (max(△Sf lood)) is 16,800 km 2 , the associated maximum error (σ Sf lood ) is 8.5 of this latter value, the maximum error on the water level is assumed to 0.03 m (see Birkett, 2000 14 ).…”

On the Relationship between Suspended Sediment Concentration, Rainfall Variability and Groundwater: An Empirical and Probabilistic Analysis for the Andean Beni River, Bolivia (2003–2016)

“…In terms of relationships, Guyot et al [14] found that water discharge and solid fluxes were related, but relationships between rainfall and discharge with sediment load have not been further assessed in this Andean sub-basin. Recent studies [15,16] have determined that groundwater is a significant contributor to the water discharge in many Amazon headwater sub-basins and could influence sediment concentrations as well.…”

Detection of groundwater storage variability based on GRACE and CABLE model in the Murray-Darling Basin

“…In general, the SWE and SM can be simulated from hydrological models such as GLDAS, W3RA and WGHM, of which the GLDAS is the most commonly model. In recent years, there have been many studies of the retrieval of groundwater changes in different regions using the GRACE satellite gravity data and hydrological models, e.g., Mississippi River basin, the North China Plain, Amazon Basin [5][6][7].…”