Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins
The Gravity Recovery and Climate Experiment (GRACE) mission has provided us with unforeseen information on terrestrial water-storage (TWS) variability, contributing to our understanding of global hydrological processes, including hydrological extreme events and anthropogenic impacts on water storage...
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doaj-8d1bf01dca694db4b23662129e066f192020-11-25T00:10:07ZengMDPI AGRemote Sensing2072-42922019-10-011121248710.3390/rs11212487rs11212487Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical BasinsDavi de C. D. Melo0Augusto Getirana1Department of Soils and Rural Engineering, Federal University of Paraíba, Areia, PB 58397-000, BrazilHydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USAThe Gravity Recovery and Climate Experiment (GRACE) mission has provided us with unforeseen information on terrestrial water-storage (TWS) variability, contributing to our understanding of global hydrological processes, including hydrological extreme events and anthropogenic impacts on water storage. Attempts to decompose GRACE-based TWS signals into its different water storage layers, i.e., surface water storage (SWS), soil moisture, groundwater and snow, have shown that SWS is a principal component, particularly in the tropics, where major rivers flow over arid regions at high latitudes. Here, we demonstrate that water levels, measured with radar altimeters at a limited number of locations, can be used to reconstruct gridded GRACE-based TWS signals in the Amazon basin, at spatial resolutions ranging from 0.5 to 3°, with mean absolute errors (MAE) as low as 2.5 cm and correlations as high as 0.98. We show that, at 3° spatial resolution, spatially-distributed TWS time series can be precisely reconstructed with as few as 41 water-level time series located within the basin. The proposed approach is competitive when compared to existing TWS estimates derived from physically based and computationally expensive methods. Also, a validation experiment indicates that TWS estimates can be extrapolated to periods beyond that of the model regression with low errors. The approach is robust, based on regression models and interpolation techniques, and offers a new possibility to reproduce spatially and temporally distributed TWS that could be used to fill inter-mission gaps and to extend GRACE-based TWS time series beyond its timespan.https://www.mdpi.com/2072-4292/11/21/2487graceradar altimetryamazonterrestrial water storagesurface water |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Davi de C. D. Melo Augusto Getirana |
spellingShingle |
Davi de C. D. Melo Augusto Getirana Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins Remote Sensing grace radar altimetry amazon terrestrial water storage surface water |
author_facet |
Davi de C. D. Melo Augusto Getirana |
author_sort |
Davi de C. D. Melo |
title |
Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins |
title_short |
Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins |
title_full |
Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins |
title_fullStr |
Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins |
title_full_unstemmed |
Radar Altimetry as a Proxy for Determining Terrestrial Water Storage Variability in Tropical Basins |
title_sort |
radar altimetry as a proxy for determining terrestrial water storage variability in tropical basins |
publisher |
MDPI AG |
series |
Remote Sensing |
issn |
2072-4292 |
publishDate |
2019-10-01 |
description |
The Gravity Recovery and Climate Experiment (GRACE) mission has provided us with unforeseen information on terrestrial water-storage (TWS) variability, contributing to our understanding of global hydrological processes, including hydrological extreme events and anthropogenic impacts on water storage. Attempts to decompose GRACE-based TWS signals into its different water storage layers, i.e., surface water storage (SWS), soil moisture, groundwater and snow, have shown that SWS is a principal component, particularly in the tropics, where major rivers flow over arid regions at high latitudes. Here, we demonstrate that water levels, measured with radar altimeters at a limited number of locations, can be used to reconstruct gridded GRACE-based TWS signals in the Amazon basin, at spatial resolutions ranging from 0.5 to 3°, with mean absolute errors (MAE) as low as 2.5 cm and correlations as high as 0.98. We show that, at 3° spatial resolution, spatially-distributed TWS time series can be precisely reconstructed with as few as 41 water-level time series located within the basin. The proposed approach is competitive when compared to existing TWS estimates derived from physically based and computationally expensive methods. Also, a validation experiment indicates that TWS estimates can be extrapolated to periods beyond that of the model regression with low errors. The approach is robust, based on regression models and interpolation techniques, and offers a new possibility to reproduce spatially and temporally distributed TWS that could be used to fill inter-mission gaps and to extend GRACE-based TWS time series beyond its timespan. |
topic |
grace radar altimetry amazon terrestrial water storage surface water |
url |
https://www.mdpi.com/2072-4292/11/21/2487 |
work_keys_str_mv |
AT davidecdmelo radaraltimetryasaproxyfordeterminingterrestrialwaterstoragevariabilityintropicalbasins AT augustogetirana radaraltimetryasaproxyfordeterminingterrestrialwaterstoragevariabilityintropicalbasins |
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