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
<p>We have aimed to improve the understanding of regional water and energy budgets in large catchments from observations, focusing on the period 2002-2013. To do this we have utilised new available satellite data from the Gravity Recovery and Climate Experiment (GRACE).&#160; Despite recent improvements in remote sensing capabilities, we still see inconsistencies amongst datasets. Observed surface energy fluxes from CERES and FluxCOM indicate unrealistic increases/decreases in surface energy storage over different catchments. We also see imbalances in the water budget, suggesting inaccuracies in the measurements. In order to assess these imbalances, we introduce a flux-inferred surface storage (FIS) for both water and energy, based on integrating the flux observations. This exposes mismatches in seasonal water storage as well as important interannual variability. We have produced optimised estimates for each component of the terrestrial water and energy budgets based on observations and their relative uncertainties. Our new optimisation approach ensures that 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. Flux adjustments remain small and are evaluated using a chi squared test. By using multiple data products, the optimisation reduces formal uncertainties on the budget variables. When compared with results from previous literature, our estimates show good agreement with GRACE variability and trends on account of the multiple timescale constraints imposed during the optimisation. We next aim to extend our approach to include carbon budgets alongside the water and energy budgets to produce a truly coupled Earth system cycling analysis, with applications such as testing Earth and climate circulation models.</p>
Abstract. Quantifying regional water and energy fluxes much more accurately from observations is essential for assessing the capability of 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 % precipitation by basin, and the magnitude of the imbalance between the net radiation and the corresponding turbulent heat fluxes ranges between 1 and 12 W m−2 in the long-term average. In order to further assess these imbalances, a flux-inferred surface storage (Sfi) is used for both water and energy, based on integrating the flux observations. This exposes mismatches in seasonal water storage in addition to important inter-annual variability between GRACE (Gravity Recovery and Climate Experiment) and the storage suggested by the other flux observations. Our optimisation ensures that the flux estimates are consistent with the 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 inter-annual variability from observations is retained. The optimisation also reduces formal uncertainties for individual flux components. When compared with results from the previous literature in basins such as the Mississippi, Congo, and Huang He rivers, our results show better agreement with GRACE variability and trends in each case.
No abstract
No abstract
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.