Simple Direct Evapotranspiration Measurements with a New Cost-Optimized ET Flux Sensor

Water is a critical resource for hydrology and water management. With an estimated 2 billion people already affected by water scarcity and a projected 3 billion facing shortages by 2050, optimizing water management is crucial for sustainable water use.

Evapotranspiration (ET) plays a vital role in the global water cycle, moving a staggering 500,000 km3 of water annually, with 70,000 km3 occurring over land. This amount surpasses the global water demand of approximately 4,600 km3 per year. By conserving just 5-10% of ET through retention in soil, groundwater, or freshwater bodies, a significant contribution can be made towards solving the global water scarcity issue.

Accurate measurement of ET is essential for effective water management in specific areas. Unfortunately, conventional models such as potential, reference, max, equilibrium, and pan do not achieve the necessary level of accuracy, which is better than 5-10%. However, direct ET measurements using the eddy covariance method provide the required resolution. Historically, the high cost and complexity of this approach have limited its usage primarily to academic research.

To address these challenges, a new cost-effective solution for direct, automated, and real-time ET measurements has been developed. This technology extends the application of eddy covariance ET measurements beyond academia to broader research, regulatory, and commercial domains. The LI-710 sensor is a user-friendly device that measures ET, sensible heat, temperature, humidity, and air pressure every 30 minutes. It is significantly more affordable than typical flux stations, costing 5-10 times less, and consumes 3-15 times less power. Moreover, it can be easily installed and utilized by individuals with limited experience in the field.

The extensive field test results of this innovative technology will be compared with traditional higher-cost research-grade eddy covariance systems. By providing more accurate and affordable ET measurements, this new technology has the potential to optimize water management in various hydrological settings. Ultimately, it contributes to addressing the global water scarcity problem through sustainable water use.