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Cross-validating precipitation datasets in the Indus River basin

Published version
Peer-reviewed

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Authors

Baudouin, JP 
A Petrie, C 

Abstract

jats:pAbstract. Large uncertainty remains about the amount of precipitation falling in the Indus River basin, particularly in the more mountainous northern part. While rain gauge measurements are often considered as a reference, they provide information for specific, often sparse, locations (point observations) and are subject to underestimation, particularly in mountain areas. Satellite observations and reanalysis data can improve our knowledge but validating their results is often difficult. In this study, we offer a cross-validation of 20 gridded datasets based on rain gauge, satellite, and reanalysis data, including the most recent and less studied APHRODITE-2, MERRA2, and ERA5. This original approach to cross-validation alternatively uses each dataset as a reference and interprets the result according to their dependency on the reference. Most interestingly, we found that reanalyses represent the daily variability of precipitation as well as any observational datasets, particularly in winter. Therefore, we suggest that reanalyses offer better estimates than non-corrected rain-gauge-based datasets where underestimation is problematic. Specifically, ERA5 is the reanalysis that offers estimates of precipitation closest to observations, in terms of amounts, seasonality, and variability, from daily to multi-annual scale. By contrast, satellite observations bring limited improvement at the basin scale. For the rain-gauge-based datasets, APHRODITE has the finest temporal representation of the precipitation variability, yet it importantly underestimates the actual amount. GPCC products are the only datasets that include a correction factor of the rain gauge measurements, but this factor likely remains too small. These findings highlight the need for a systematic characterisation of the underestimation of rain gauge measurements. </jats:p>

Description

Keywords

3707 Hydrology, 3701 Atmospheric Sciences, 37 Earth Sciences

Journal Title

Hydrology and Earth System Sciences

Conference Name

Journal ISSN

1027-5606
1607-7938

Volume Title

24

Publisher

Copernicus GmbH
Sponsorship
European Research Council (648609)
Biotechnology and Biological Sciences Research Council (BB/P027970/1)
European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 648609)