Modeling apple surface temperature dynamics based on weather data.

Area of Science:

• Horticulture
• Agricultural Meteorology
• Plant Physiology

Background:

• Apple sunburn, caused by excessive solar radiation, leads to substantial economic losses in fruit marketing.
• Understanding fruit surface temperature (FST) dynamics is crucial for managing sunburn damage.

Purpose of the Study:

• To develop and validate an energy balance-based model for simulating apple FST dynamics.
• To provide a tool for more accurate FST estimation than methods relying solely on air temperature.

Main Methods:

• Collected hourly weather data (temperature, humidity, solar radiation, wind speed) over two months.
• Measured "Fuji" apple FSTs using an infrared camera in an orchard setting.
• Validated the simulated FSTs against measured data, calculating root-mean-square error (RMSE).

Main Results:

• The FST model achieved an RMSE of less than 2.0 °C for sun-exposed apples.
• Accurate apple surface emissivity estimation was identified as critical for model performance.
• The model accurately described apple thermal performance under varying solar radiation levels.

Conclusions:

• The developed model accurately simulates apple FST dynamics, improving upon air temperature-based estimates.
• This tool offers valuable insights for implementing effective apple sunburn protection management strategies.