The evaporative loss from global lakes (natural and artificial) is a critical component of the terrestrial water and energy balance. However, the evaporation volume of these water bodies—from the spatial distribution to the long-term trend—is as of yet unknown. Here, using satellite observations and modeling tools, we quantified the evaporation volume from 1.42 million global lakes from 1985 to 2018. We find that the long-term average lake evaporation is 1500 ± 150 km3 year−1 and it has increased at a rate of 3.12 km3 year−1. The trend attributions include an increasing evaporation rate (58%), decreasing lake ice coverage (23%), and increasing lake surface area (19%). While only accounting for 5% of the global lake storage capacity, artificial lakes (i.e., reservoirs) contribute 16% to the evaporation volume. Our results underline the importance of using evaporation volume, rather than evaporation rate, as the primary index for assessing climatic impacts on lake systems.
Led by Huilin Gao, associate professor in the Zachry Department of Civil and Environmental Engineering at Texas A&M University, researchers created the global lake evaporation volume (GLEV) dataset. It leverages modeling and remote sensing to provide the first long-term monthly time series for 1.42 million individual natural lakes and artificial reservoirs worldwide.
The researchers published their findings in Nature Communications. About 87% of fresh surface water in liquid form is stored in natural and artificial lakes (i.e., reservoirs). While the evaporation volume from these global lakes is substantial, little is known about its spatial distribution and its long-term trend.
From 1985 to 2018, researchers discovered that long-term average lake evaporation volume has increased at a rate of 3.12 cubic kilometers per year. The trend attributions include an increased evaporation rate of 58%, decreased lake ice coverage of 23% and increased lake surface area of 19%.
“With regard to evaporation loss, this study will be an invaluable venue to serve water resources researchers and decision-makers,” Gao said. “Our findings have significant environmental, societal and economic implications as the global evaporative loss will be accelerated and further exacerbated in the future under global warming.
“From a global perspective, the total reservoir evaporation can be larger than the combined use of domestic and industrial water. However, even in the United States, very few lakes/reservoirs have reliable evaporation data.” Without accurately quantifying the magnitude and trend of volumetric evaporation loss individually for the millions of global lakes, researchers say reliable water and energy resources projections can’t be made. This freely available dataset can benefit decision-makers and the wider science community.
“With results for individual water bodies, GLEV can really help improve reservoir management decision-making all over the world, especially under increasing drought events and population growth,” Gao said. “This dataset helps the science community better understand the role that these water bodies play in Earth systems, from global weather forecasting, flood and drought modeling to Earth system modeling under climate change.”
Sources:
Nature communications
https://www.nature.com/articles/s41467-022-31125-6 .
Provided by the IKCEST Disaster Risk Reduction Knowledge Service System
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