ICT International

Advancing soil, plant and environmental decision making

Evapotranspiration Monitoring Station

The ICT International Evapotranspiration Monitoring Station is an integrated weather stations to measure and monitor evapotranspiration by measuring solar radiation, air temperature, relative humidity, and wind speed. With these measured values, the Penman-Monteith method is applied to calculate the reference crop evapotranspiration (ETo) and crop evapotranspiration (ETc).  

The Evapotranspiration Monitoring Station sensing components include: 

  • Apogee SP-421-SS (Solar Radiation) 
  • AWS500L (temperature, relative humidity, barometric pressure, wind speed, wind direction) 
  • RIM-4799-STD (rainfall) 

These are connected using an MFR-NODE for either CAT-M1/NB-IoT (MFR-NODE-C) or LoRaWAN (MFR-NODE-L) to the Eratos cloud database. 

Sensors are measured at user configurable 10 – 20-minute intervals and transmitted to the Eratos cloud-based database via either CAT-M1/NB-IoT (MFR-NODE-C) or LoRaWAN (MFR-NODE-L) networks where it is processed using ICT International’s FAO Penman-Monteith workflow. All user defined inputs to the equation (including location, altitude, weather station height, crop height and crop co-efficient) are entered at the workflow level, removing onsite configuration requirements, and allowing the user to change crop coefficients at any stage in the growing season. 

The workflow outputs calculated evapotranspiration (ETo) and crop evapotranspiration (ETc) in millimetres (mm) per hour, with daily or weekly totals derived from the cumulative of hourly totals.  

ICT International’s Evapotranspiration Monitoring Station is supplied preconfigured and pre-wired to the sensor array. Additional crop management sensors can be added upon request. 

Why measure evapotranspiration? 

Evapotranspiration is the combined loss of water from plants and the soil to the atmosphere. This can be calculated by measuring solar radiation, air temperature, relative humidity, and wind speed. The standard method for calculating evapotranspiration is the United Nations Food and Agriculture Organization (FAO) Penman-Monteith method.