Lake pulses driven by glacier melting and climate variability

Area of Science:

• Glaciology and Hydrology
• Climate Change Science
• Environmental Modeling

Background:

• The Tibetan Plateau's glaciers are crucial for freshwater and climate regulation, acting as sensitive indicators of climate change.
• Understanding glacier-fed hydrological systems is vital for water resource management and climate adaptation planning.
• The Blue Moon Lake Valley (BMLV), fed by Baishui River Glacier No. 1, experiences subtle yet significant water level fluctuations (lake pulse phenomenon).

Purpose of the Study:

• To investigate the dynamic fluctuations in the water level of the Blue Moon Lake Valley.
• To analyze the interactions among glacier melt dynamics, climatic variables, and hydrological responses.
• To quantify the lake pulse phenomenon and its drivers.

Main Methods:

• Employed fast Fourier transform (FFT), multivariate regression (MVR), and random forest (RF) models.
• Analyzed water level data, glacier melt rates, and key climatic variables (temperature, solar radiation, precipitation, etc.).
• Calculated rate of change (ROC) in water level and glacier melt, cumulative sum (CS), and transit times.

Main Results:

• Water level ROC fluctuates between -0.006 and 0.01 m/min, with a median of -7.24E-06 m/min, influenced by glacier melt and precipitation.
• Maximum CS of 0.09 m indicates a net water level increase driven by precipitation, reduced evaporation, and increased glacier melt.
• Temperature is a critical factor influencing glacier melt and water level; melt peaks occur every ~2.87 hours, while water level peaks occur every ~6.5 hours, with a meltwater transit time of ~4.16 hours.

Conclusions:

• The study systematically elucidates the hydrological dynamics of the BMLV, highlighting the significant impact of glacier melt and climate variables.
• Findings underscore the importance of considering subtle hydrological fluctuations for accurate water resource assessment.
• This research provides crucial data for water resource management, ecosystem health, and climate change adaptation in glacier-dependent regions.