Abstract
The Surface Water and Ocean Topography (SWOT) space mission will map surface area and water level changes in lakes at the global scale. Such new data are of great interest to better understand and model lake dynamics as well as to improve water management. In this study, we used the large-scale SWOT simulator developed at the French Space National Center (CNES) to estimate the expected measurement errors of the water level of different water bodies in France. These water bodies include five large reservoirs of the Seine River and numerous small gravel pits located in the Seine alluvial plain of La Bassée upstream of the city of Paris. The results show that the SWOT mission will allow to observe water levels with a precision of a few tens of centimeters (10 cm for the largest water reservoir (Orient), 23 km2), even for the small gravel pits of size of a few hectares (standard deviation error lower than 0.25 m for water bodies larger than 6 ha). The benefit of the temporal sampling for water level monitoring is also highlighted on time series of pseudo-observations based on real measurements perturbed with the simulated noise errors. Then, the added value of these future data for the simulation of lake energy budgets is shown using the FLake lake model through sensitivity experiments. Results show that the SWOT data will help to model the surface temperature of the studied water bodies with a precision better than 0.5 K and the evaporation with an accuracy better than 0.2 mm/day. These large improvements compared to the errors obtained when a constant water level is prescribed (1.2 K and 0.6 mm/day) demonstrate the potential of SWOT for monitoring the lake energy budgets at global scale in addition to the other foreseen applications in operational reservoir management.
Highlights
water surface elevation (WSE) errors were simulated with the large-scale Surface Water and Ocean Topography (SWOT) simulator on the studied Seine reservoirs and La Bassée gravel pits
The distribution of the errors calculated over the five-year simulation (Figure 2b) shows the lowest range of variation for the orbit 363 compared to the orbits 570 and 264
We focused on the Seine basin and its large reservoirs and alluvial plain upstream the city of Paris, and tried to assess the future contribution of these new observations to follow water levels and surface fluxes through a lake energy budget model
Summary
The impacts of artificial reservoirs on the terrestrial hydrological cycle appeared to be quite important, by affecting the river regimes and by substantially contributing to freshwater withdrawals through the increased evaporation and the promotion of irrigation linked to the increased water availability [5,6]. As an example, it was demonstrated how the large increase of reservoirs in China during the last 20 years have impacted regional water budgets, especially evapotranspiration and its long-term trends [7]. In the same part of the world, a simple dam operation model was developed to explain the time variability of the discharges of the Yellow river and to separate the effects of climate change from human infrastructures [8]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.