Sediment transport in South Asian rivers high enough to impact satellite gravimetry

authored by: Alexandra Klemme, Thorsten Warneke, Heinrich Bovensmann, Matthias Weigelt, Jürgen Müller, Tim Rixen, Justus Notholt, Claus Lämmerzahl
Abstract: Satellite gravimetry is used to study the global hydrological cycle. It is a key component in the investigation of groundwater depletion on the Indian subcontinent. Terrestrial mass loss caused by river sediment transport is assumed to be below the detection limit in current gravimetric satellites of the Gravity Recovery and Climate Experiment Follow-On mission. Thus, it is not considered in the calculation of terrestrial water storage (TWS) from such satellite data. However, the Ganges and Brahmaputra rivers, which drain the Indian subcontinent, constitute one of the world’s most sediment-rich river systems. In this study, we estimate the impact of sediment mass loss within their catchments on local trends in gravity and consequential estimates of TWS trends. We find that for the Ganges–Brahmaputra–Meghna catchment sediment transport accounts for (4 ± 2) % of the gravity decrease currently attributed to groundwater depletion. The sediment is mainly eroded from the Himalayas, where correction for sediment mass loss reduces the decrease in TWS by 0.22 cm of equivalent water height per year (14 %). However, sediment mass loss in the Brahmaputra catchment is more than twice that in the Ganges catchment, and sediment is mainly eroded from mountain regions. Thus, the impact on gravimetric TWS trends within the Indo–Gangetic Plain – the main region identified for groundwater depletion – is found to be comparatively small (< 2 %).
Organisation(s): Institute of Geodesy
External Organisation(s): University of Bremen
Leibniz Centre for Tropical Marine Research (ZMT)
Type: Article
Journal: Hydrology and Earth System Sciences
Volume: 28
Pages: 1527–1538
No. of pages: 12
ISSN: 1027-5606
Publication date: 04.04.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Water Science and Technology, Earth and Planetary Sciences (miscellaneous)
Sustainable Development Goals: SDG 15 - Life on Land
Electronic version(s): https://doi.org/10.5194/hess-28-1527-2024 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@article{c31c5aa39c244a27ba38f0041f6a7057,
title = "Sediment transport in South Asian rivers high enough to impact satellite gravimetry",
abstract = "Satellite gravimetry is used to study the global hydrological cycle. It is a key component in the investigation of groundwater depletion on the Indian subcontinent. Terrestrial mass loss caused by river sediment transport is assumed to be below the detection limit in current gravimetric satellites of the Gravity Recovery and Climate Experiment Follow-On mission. Thus, it is not considered in the calculation of terrestrial water storage (TWS) from such satellite data. However, the Ganges and Brahmaputra rivers, which drain the Indian subcontinent, constitute one of the world{\textquoteright}s most sediment-rich river systems. In this study, we estimate the impact of sediment mass loss within their catchments on local trends in gravity and consequential estimates of TWS trends. We find that for the Ganges–Brahmaputra–Meghna catchment sediment transport accounts for (4 ± 2) % of the gravity decrease currently attributed to groundwater depletion. The sediment is mainly eroded from the Himalayas, where correction for sediment mass loss reduces the decrease in TWS by 0.22 cm of equivalent water height per year (14 %). However, sediment mass loss in the Brahmaputra catchment is more than twice that in the Ganges catchment, and sediment is mainly eroded from mountain regions. Thus, the impact on gravimetric TWS trends within the Indo–Gangetic Plain – the main region identified for groundwater depletion – is found to be comparatively small (< 2 %).",
author = "Alexandra Klemme and Thorsten Warneke and Heinrich Bovensmann and Matthias Weigelt and J{\"u}rgen M{\"u}ller and Tim Rixen and Justus Notholt and Claus L{\"a}mmerzahl",
note = "This study in these interdisciplinary realms of geodesy and climate research was enabled by funding from the Norddeutscher Wissenschaftspreis (North German Science Prize). The article processing charges for this open-access publication were covered by the University of Bremen.",
year = "2024",
month = apr,
day = "4",
doi = "10.5194/hess-28-1527-2024",
language = "English",
volume = "28",
pages = "1527–1538",
journal = "Hydrology and Earth System Sciences",
issn = "1027-5606",
publisher = "European Geosciences Union",
number = "7",
}