[Application and verification of distributed model in simulating watershed evapotranspiration]

Area of Science:

• Hydrology
• Environmental Science
• Water Resource Management

Background:

• Evapotranspiration is a critical component of the water cycle, influencing runoff and water availability.
• Accurate simulation of evapotranspiration is essential for effective watershed management and hydrological modeling.
• Previous studies often lacked the spatial and temporal resolution to capture watershed-specific evapotranspiration dynamics.

Purpose of the Study:

• To simulate the temporal and spatial distribution of potential and actual evapotranspiration in the upper Zagunao watershed.
• To develop and validate a distributed modeling approach for evapotranspiration estimation.
• To provide an effective method for incorporating actual evapotranspiration into distributed rainfall-runoff models.

Main Methods:

• Employed a distributed hydrological model utilizing conventional meteorological data from 1989-2000.
• Utilized 500 m grids and a 1-day time step to capture spatial and temporal heterogeneity.
• Simulated potential evapotranspiration using a modified Penman-Monteith Equation and proposed a novel method for actual evapotranspiration calculation.

Main Results:

• The distributed model demonstrated a reasonable temporal and spatial distribution of evapotranspiration.
• The simulation of normal annual evapotranspiration showed a low relative error of 3.47% over 12 years.
• The proposed method effectively estimated actual evapotranspiration considering underlying hydrological conditions.

Conclusions:

• The developed distributed model provides a robust and accurate method for simulating evapotranspiration in watersheds.
• The findings offer valuable insights for improving hydrological modeling, particularly in rainfall-runoff simulations.
• This research contributes to better understanding and managing water resources in mountainous regions like the upper Zagunao watershed.