Lake evaporation patterns change with climate change

Figure 1: Lake evaporation and spatially coupled future changes in hydrological climate and their impact on regional lake volume changes. Spatial pattern of future changes in lake evaporation based on CLM projections (under RCP8.5; 2071–2100 minus 1971–2000). b Lake evaporation averaged in tropical America (12 ° S–9 ° N; 70 ° W–50 ° W and 10 ° N–20 ° N; 105 ° W–85 ° W), Mediterranean (35 ° N) Future Changes in –47 ° N; 10 ° W–40 ° E), Southeastern China (20 ° N–35 ° N; 110 ° E–125 ° E), Great Lakes (41 ° N–49 ° N; 92) ° W–77 ° W), Tibetan Plateau (28 ° N–36 ° N; 75 ° E–95 ° E), and high latitudes (60 ° N polar direction). Spatial pattern of future changes in land PE based on the average prediction of the CMIP5 model of c22. d Future changes in land PE averaged in 6 regions. The mean and standard deviation of the ensemble projection is displayed in a bar graph. Qualitative prediction of future lake volume changes based on PE on land and lakes. f Changes in the proportion of lake and land PE are averaged in the six regions. Areas with a dry future hydrological climate, namely tropical America, the Mediterranean Sea, and southeastern China, are indicated by black rectangles. Credit: DOI: 10.1038 / s43247-021-00327-z

For many, warm summer days are characterized by spending time swimming in the lake. Lakes are more important than just recreation and serve as a major global source of freshwater. However, as the temperature continues to rise, so does the lake. As the world’s average temperature rises, lake evaporation is projected to increase at twice the rate of ocean evaporation.

However, future increases in lake evaporation will vary widely from region to region. Researchers at the Pacific Northwest National Laboratory (PNNL) have found that climate change maximizes lake evaporation in areas such as the Mediterranean, southeastern China, and tropical America.

These differences in the impact of climate change on future lake evaporation are related to changes in the hydrological climate of the region or the net amount of water the region receives. In areas with a dry hydrological climate, the increase in lake evaporation is amplified. However, these increases will be curbed in areas with a humid hydrological climate, such as above the Arctic Circle and across the Tibetan Plateau.

Researchers already know that changes in hydrological climate affect the influx of water into lakes. By finding the relationship between changes in hydrological climate and changes in lake evaporation, PNNL researchers can move on to predict changes in lake volume in areas that depend on water inflow and evaporation.

“Lake is an important source of freshwater that people rely on for agriculture,” said Battelle Fellow and PNNL geoscientist Ruby Leon. “Understanding how volumes change at the regional level can help you manage Water resourcesEspecially in areas where water shortages are already a concern. “

Establishing a link between large hydrological climate and lake evaporation

Most of the studies to date that have focused on lake evaporation are increasing globally, without exploring the differences that appear on a regional scale. The team has identified the important role of hydrological climate change in increasing evaporation of lakes in the region.

They found a close correlation between changes in hydrological climate and spatial patterns of increased evaporation of lakes. In particular, the increase in lake evaporation is most pronounced in areas with dry hydrological climates, but diminishes in future hydrological climates.

Lake evaporation patterns change with climate change

In a dry hydrological climate, multiple factors cause increased evaporation of the lake. Credits: Stephanie King based on schematic diagram by Wenyu Zhou of Pacific Northwest National Laboratory

“Given the spatial correlation of Climate simulationWenyu Zhou, a PNNL geoscientist, said, “I wondered if changes in the hydrological climate might affect changes in lake evaporation. We looked at models and theoretical evaporation equations to see if they were correct. I looked it up. “

However, the mathematical link between evaporation and hydrological climate was hidden in existing evaporation equations. “Wenyu has taken an important step in rebuilding the traditional evaporative formula,” says Leung. “Now we can directly relate lake evaporation to the hydrological climate of the region.”

Applying the reformulated equations to the model’s predictions revealed that a dry hydrological climate promotes lake evaporation. This is done in two ways. First, the humidity changes and evaporation increases. Second, it reduces the amount of clouds in the atmosphere and increases the amount of sunlight that illuminates the lake.

Hydrological climate change, lake volume change

The clear relationship between regional hydrological climate and lake evaporation has important implications for modeling lake volume changes. The dry hydrological climate promotes evaporation of the lake and reduces the flow of water to the lake. This both contributes to the reduction of the volume of the lake. This relationship gives researchers confidence in understanding past changes and predicting future changes in lake water volumes.

Areas with a drier hydrological climate and higher lake volume reductions may face further water scarcity. This is already a reality in some areas. Dryness of Lake Poopó in Bolivia is associated with human activity and climate change and is a prominent example of extreme lake volume changes.

“Understanding that the hydrological climate of a region affects both evaporation to the lake and the flow of water is an important step in estimating the volume change of the lake,” says Leung. “Most lake models used in climate models have not yet calculated the volume of the lake.”

Hydrological Climate change and newly identified bonds between lakes evaporation The increase allows the team to qualitatively predict future changes in lake water volume. The team is now looking at another difficult task. It is to quantify how much water will remain in the lake in the future. This can help water resource managers more effectively protect their declining water supply.

The report found that most of the Great Lakes will not approach record heights in the next six months.

For more information:
Wenyu Zhou et al, the spatial pattern of lake evaporation increases under global warming associated with changes in the hydrological climate of the region, Communication Earth and environment (2021). DOI: 10.1038 / s43247-021-00327-z

Quote: The lake evaporation pattern was obtained from on February 16, 2022 (February 2022). 16th) will change

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Lake evaporation patterns change with climate change

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