15 Dec 2022
15 Dec 2022
Status: this preprint is open for discussion.

Water and Energy budgets over hydrological basins on short and long timescales

Samantha Petch1, Bo Dong1,2, Tristan Quaife1,2, Rob King3, and Keith Haines1,2 Samantha Petch et al.
  • 1Department of Meteorology, University of Reading, Reading, UK
  • 2National Centre for Earth Observation, University of Reading, Reading, UK
  • 3Met Office, Exeter, UK

Abstract. Quantifying regional water and energy fluxes much more accurately from observations is essential for improving climate and earth system models, and their ability to simulate future change. This study uses satellite observations to produce monthly flux estimates for each component of the terrestrial water and energy budget over selected large river basins from 2002 to 2013. Prior to optimisation the water budget residuals vary between 1.5 % and 35 % of precipitation by basin, and the imbalance between the net radiation and the corresponding turbulent heat fluxes ranges between ± 10 Wm−2 in the long term average. In order to further assess these imbalances, a flux-inferred surface storage (FIS) is used for both water and energy, based on integrating the flux observations. This exposes mismatches in seasonal water storage as well as important interannual variability.

Our optimisation ensures the flux estimates are consistent with total water storage changes from GRACE on short (monthly) and longer timescales, while also balancing a coupled long term energy budget, by using a sequential approach. All the flux adjustments made during the optimisation are small and within uncertainty estimates using a χ2 test, and interannual variability from observations is retained. The optimisation also reduces formal uncertainties on individual flux components. When compared with results from previous literature in basins such as the Mississippi, Congo and Huang He River, the FIS metrics show the better agreement with GRACE variability and trends in each case

Samantha Petch et al.

Status: open (until 09 Feb 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1237', Anonymous Referee #1, 08 Jan 2023 reply
  • RC2: 'Review', Ruud van der Ent, 12 Jan 2023 reply
    • AC1: 'Reply on RC2', Samantha Petch, 03 Feb 2023 reply
  • RC3: 'Comment on egusphere-2022-1237', Anonymous Referee #3, 18 Jan 2023 reply

Samantha Petch et al.

Samantha Petch et al.


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Short summary
Gravitational measurements of water storage from GRACE can improve our understanding of the water budget. Here we produce new flux estimates over large river catchments based on observations which close the monthly water budget whilst ensuring consistency with GRACE on both short and long timescales. We also use energy data to provide additional constraints and balance the long-term energy budget. These more accurate flux estimates are important for evaluating climate models.