Jakarta – A new study introduces a breakthrough in global lake monitoring that could significantly improve water resource management in the face of climate change and increasing human pressures. Researchers have developed a proxy-based method that leverages Landsat satellite imagery and ICESat laser altimeters to reconstruct the water levels of lakes worldwide from 1992 to 2018.
The study, published in the Water Resources Research recently, assessed reconstructed water levels across 342 lakes varying in size from 1 to 81,844 square kilometres. The findings reveal that the new method achieves a median root-mean-square error (RMSE) of 0.66 metres, marking a 27%–32% improvement over previous methods. This precision is notable, especially considering the historical challenge posed by sparse data from in situ gauges and the limited coverage of satellite altimeters.
Fangfang Yao, a surface hydrologist and a climate fellow at University of Virginia’s Environmental Institute who lead the research also published a study last year revealing that more than half of the world’s large lakes, including the Caspian Sea and Lake Titicaca, have shrunk since the early 1990s. He said the phenomenon is triggered by a combination of climate warming and unsustainable human water consumption.
A warming climate and human water consumption are driving at least half the decline in natural lake volumes. This decline is fatal, not only for lake ecosystems, but also for the millions of people who depend on them.
Innovative approach
This innovative approach not only utilises the recent ICESat-2 laser altimeter data launched in 2018 but also benefits from a robust construction of high-quality hypsometry, achieving a median correlation coefficient (R^2) of 0.92. Most of the reconstructed water level time series provide bi-monthly or more frequent updates, allowing for more dynamic and informed management of these crucial natural resources.
The integration of this technology has the potential to create a comprehensive global inventory of lake levels, providing critical insights for policymakers and environmental managers to tackle the pressing issues of water scarcity and ecosystem preservation. As lakes continue to hit record-low levels due to various stressors, such detailed and frequent monitoring becomes indispensable in strategizing sustainable water use and conservation efforts. (Hartatik)