The MEER team in India has set up an experiment on the rooftop of their office building in Hanuman Nagar, Pune. The experiment aims to check the calibration of the sensors in extreme conditions of solar radiation, humidity, and wind flow. With this goal in mind, the team has introduced one variable at a time while keeping the others constant. They have added solar radiation as a variable while keeping the wind speed constant at zero.

The team has constructed a square glass chamber to create an absolute condition and make solar radiation uniform throughout the chamber. Each side of the chamber is sealed, and the bottom part of the glass is kept at a black-painted surface to gradually increase heat from top to bottom, creating a heat gradient. Since the glass traps infrared radiation, it is assumed that the air temperature inside will be 20 degrees Celsius higher than the outside environment. This will create an extreme condition for calibrating the sensor.

As the sensors are used to measure the temperature of rooftops, where heat is absorbed and the readings are higher than the outside environment, the same environment has been created inside the chamber to calibrate the sensors. The team created this experiment to test the maximum temperature range that the sensors can measure accurately in extreme conditions. The testing is critical in terms of monitoring the accuracy of the sensors.

The calibration test phase will run in two sub-phases:
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Phase 1: Data logger and probes are kept at the same temperature, ensuring the sensors are calibrated and working properly.
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Phase 2: Half of the data loggers are kept outside in a cool environment, and the other half are kept inside the glass chamber in a relatively hot environment to observe the difference in temperature readings. This will help the team determine the sensors' accuracy in extreme conditions.

The experiment, which will run for four weeks, changing one parameter at a time to ensure accurate results, is of utmost importance. With temperatures in India reaching 45 degrees Celsius daily, the calibration of the sensors will be crucial for future testing of MEER sheets in the community. This experiment, a significant step towards achieving that goal, underscores the importance of our work

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