Design and Performance Analysis of Meteorological Temperature Sensor Calibration Device Using Gas Cavities

In order to solve the problem of a meteorology temperature sensor not being able to touch a liquid, an open gas cavity structure immersed in the liquid was designed. According to the characteristics that the temperature sensing position of the meteorological temperature sensor is in the bottom area of the gas cavity, a simulation and experimental study of the bottom temperature field of φ50 mm cylindrical and φ(50-35-25) mm stepped column gas cavities were carried out. The experimental results at (−30~30) °C show that the gas stability of the gas cavities was better than that of the liquid constant temperature bath, and the performance of the cylindrical gas cavity was the best. The gas temperature stability of the stepped column gas cavity and the liquid constant temperature bath follow a strong trend. The maximum stability of the cylindrical gas cavity is 0.0054 °C, and the maximum stability of the stepped column gas cavity is 0.0080 °C. The results also show that the maximum uniformity of the stepped gas cavity is 0.0077 °C, and the maximum uniformity of the cylindrical gas cavity is 0.0528 °C. The uncertainty introduced in the measurement process was evaluated to ensure the confidence of the experimental data. The maximum value of the extended uncertainty was U = 0.0027 °C (k = 2). Compared with the solid-state constant temperature bath calibration method, the temperature sensor of different shapes can be directly placed into the gas cavity without the need for the meteorological temperature sensor to be closely attached to the wall of the gas cavity, and a sealing plug is used to seal the cavity mouth. The operation is very convenient, rapid turnover of the calibration of the meteorological temperature sensor can be achieved, and the work efficiency can be improved. Superior stability and uniformity can be obtained compared to gas constant temperature cavities. This study provides a valuable reference for the structural design of large-volume gas cavities and provides support and guarantee for global climate change monitoring.