Design Of Low Radiation Error Temperature Sensor System For Meteorological Observation

In the meteorological, temperature sensor measurement accuracy can be affected by ground long-wave radiation, direct solar radiation and ground reflected radiation, which direct solar radiation is the main factor among the three factors.In order to reduce the effects of direct solar radiation on the sensor, in traditional weather temperature observations, the thermometer screen and radiation shield are frequently used. However, there are still some shortcomings with the thermometer screen and radiation shield, which cannot shield radiation heating completely. These instruments may also compromise the continuous and uniform status of the atmosphere environment. Therefore, thermometer screen and radiation shield will not solve the problem thoroughly.A design of low radiation error temperature sensor is proposed here. It consists of two platinum resistance sensors, which have different coatings, an analog signal conditioning circuits, an embedded hardware, error-cancellation algorithm and a PC interface display. The true atmospheric temperature is calculated by using the ratio of temperature elevations of different coated sensors under different solar radiation intensity and the same wind speed. A computational fluid dynamics (CFD) method is applied to simulate the physical model to obtain the temperature field in the complex convection and solar radiation coupled thermal boundary. Also, the ratio of temperature elevations can be calculated. Hence, a reference for the design of low error radiation temperature sensor can be provided.The difference between calculated and the real atmospheric temperature is within 0.3℃. This low radiation error temperature sensor has the advantages of high precision, fast response and small size compared with temperature sensors used in conventional weather stations.