Low-water maps of the groundwater table in the central Amazon by satellite altimetry

Pfeffer, Julia; Seyler, Frédérique; Bonnet, Marie‐Paule; Calmant, Stéphane; Frappart, Frédéric; Papa, Fabrice; Paiva, Rodrigo Cauduro Dias de; Satgé, Frederic; Silva, Joécila Santos da

doi:10.1002/2013gl059134

Cited by 24 publications

(28 citation statements)

References 41 publications

(81 reference statements)

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“…On the other hand, in order to avoid negative impacts of extreme events, it is also necessary to improve our understanding of hydrological physical processes and sensitivity to droughts and floods in the Amazon region, including in groundwater storage (e.g. Pfeffer et al, 2014), river/floodplain hydrodynamic and hydrology processes (e.g. Trigg et al, 2009;Rodriguez et al, 2010;Getirana et al, 2012;Guimberteau et al, 2012;Frappart et al, 2013;Tomasella et al, 2013;Rudorff et al, 2014a, 2014b, Paiva et al, 2013a.…”

Section: Discussionmentioning

confidence: 99%

Extreme seasonal droughts and floods in Amazonia: causes, trends and impacts

Marengo

Espinoza

2015

Intl Journal of Climatology

555

512

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This paper reviews recent progress in the study and understanding of extreme seasonal events in the Amazon region, focusing on drought and floods. The review includes a history of droughts and floods in the past, in the present and some discussions on future extremes in the context of climate change and its impacts on the Amazon region. Several extreme hydrological events, some of them characterized as 'once in a century', have been reported in the Amazon region during the last decade. While abundant rainfall in various sectors of the basin has determined extreme floods along the river's main stem in 1953, 1989, 1999, 2009, 2012-2015, deficient rainfall in 1912, 1926, 1963, 1980, 1983, 1995, 1997, 1998, 2005 and 2010 has caused anomalously low river levels, and an increase in the risk and number of fires in the region, with consequences for humans. This is consistent with changes in the variability of the hydrometeorology of the basin and suggests that extreme hydrological events have been more frequent in the last two decades. Some of these intense/reduced rainfalls and subsequent floods/droughts were associated (but not exclusively) with La Niña/El Niño events. In addition, moisture transport anomalies from the tropical Atlantic into Amazonia, and from northern to southern Amazonia alter the water cycle in the region year-to-year. We also assess the impacts of such extremes on natural and human systems in the region, considering ecological, economic and societal impacts in urban and rural areas, particularly during the recent decades. In the context of the future climate change, studies show a large range of uncertainty, but suggest that drought might intensify through the 21st century.

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Section: Discussionmentioning

confidence: 99%

Extreme seasonal droughts and floods in Amazonia: causes, trends and impacts

Marengo

Espinoza

2015

Intl Journal of Climatology

555

512

View full text Add to dashboard Cite

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“…Indeed, altimetry data could be used to compute the interferometric bias with reasonable confidence if the study window is large enough to overlap a reasonable number of ICESat/GLAS points. Improvement of the flooding extent at the LW stage might also be induced, selecting the minimum values of altimetry data for the pixels overlapped by SWBD, following a similar method as proposed by Pfeffer et al [77].…”

Section: Usefulness Of Bathymetric Data In the Correction Processmentioning

confidence: 99%

Correction of Interferometric and Vegetation Biases in the SRTMGL1 Spaceborne DEM with Hydrological Conditioning towards Improved Hydrodynamics Modeling in the Amazon Basin

et al. 2015

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Abstract:In the Amazon basin, the recently released SRTM Global 1 arc-second (SRTMGL1) remains the best topographic information for hydrological and hydrodynamic modeling purposes. However, its accuracy is hindered by errors, partly due to vegetation, leading to erroneous simulations. Previous efforts to remove the vegetation signal either did not account for its spatial variability or relied on a single assumed percentage of penetration of the SRTM signal. Here, we propose a systematic approach over an Amazonian floodplain to remove the vegetation signal, addressing its heterogeneity by combining estimates of vegetation height and a land cover map. We improve this approach by interpolating the first results with drainage network, field and altimetry data to obtain a hydrological conditioned DEM. The averaged interferometric and vegetation biases over the forest zone were found to be´2.0 m and 7.4 m, respectively. Comparing the original and corrected DEM, vertical validation against Ground Control Points shows a RMSE reduction of 64%. Flood extent accuracy, controlled against Landsat and JERS-1 images, stresses improvements in low and high water periods (+24% and +18%, respectively). This study also highlights that a ground truth drainage network, as a unique input during the interpolation, achieves reasonable results in terms of flood extent and hydrological characteristics.

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“…This validation process was highly dependent on the length of the concomitant observations and on the distance to the closest gauge. Previous studies demonstrated the capability of radar altimetry to retrieve reliable water levels over water bodies larger than 200 or 300 m across [46,51,68,69], even over floodplains covered with vegetation [19,68,70]. At nadir incidence, the intensity of the returned power is weakly attenuated by the vegetation cover (at least for Leaf Area Index < 1.5; see [71]), even if the radar echo is impacted.…”

Section: Validation Of Altimetry-based Water Levelsmentioning

confidence: 99%

Surface Freshwater Storage Variations in the Orinoco Floodplains Using Multi-Satellite Observations

et al. 2014

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Variations in surface water extent and storage are poorly characterized from regional to global scales. In this study, a multi-satellite approach is proposed to estimate the water stored in the floodplains of the Orinoco Basin at a monthly time-scale using remotely-sensed observations of surface water from the Global Inundation Extent Multi-Satellite (GIEMS) and stages from Envisat radar altimetry. Surface water storage variations over [2003][2004][2005][2006][2007] exhibit large interannual variability and a strong seasonal signal, peaking during summer, OPEN ACCESSRemote Sens. 2015, 7 90 and associated with the flood pulse. The volume of surface water storage in the Orinoco Basin was highly correlated with the river discharge at Ciudad Bolivar (R = 0.95), the closest station to the mouth where discharge was estimated, although discharge lagged one month behind storage. The correlation remained high (R = 0.73) after removing seasonal effects. Mean annual variations in surface water volume represented ~170 km 3 , contributing to ~45% of the Gravity Recovery and Climate Experiment (GRACE)-derived total water storage variations and representing ~13% of the total volume of water that flowed out of the Orinoco Basin to the Atlantic Ocean.

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Low-water maps of the groundwater table in the central Amazon by satellite altimetry

Cited by 24 publications

References 41 publications

Extreme seasonal droughts and floods in Amazonia: causes, trends and impacts

Extreme seasonal droughts and floods in Amazonia: causes, trends and impacts

Correction of Interferometric and Vegetation Biases in the SRTMGL1 Spaceborne DEM with Hydrological Conditioning towards Improved Hydrodynamics Modeling in the Amazon Basin

Surface Freshwater Storage Variations in the Orinoco Floodplains Using Multi-Satellite Observations

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