Design and Experimental Validation of a High-Accuracy Naturally Ventilated Radiation Shield for Near-Surface Air Temperature Observation

Near-surface air temperature measurements are sensitive to solar radiation and ambient longwave irradiance, which can introduce measurement errors of approximately 1 °C. This study presents the design and experimental validation of a high-accuracy naturally ventilated radiation shield that operates without mechanical aspiration. Computational fluid dynamics (CFD) simulations were used to optimize a bowl–cover airflow-guiding structure and shading configuration, thereby enhancing air exchange around the sensing probe and reducing radiation-induced heating. A coupled multi-parameter simulation framework was further developed to evaluate the sensitivity of radiation error to wind speed, scattered radiation, altitude, and other environmental factors. Field intercomparison experiments were conducted using a Model 076B radiation shield as the reference and a Model 41003 radiation shield for comparison. Results show that the proposed shield exhibits a mean uncorrected radiation error of 0.12 °C, which is significantly lower than that of the 41003 shield (0.59 °C). In addition, a multilayer perceptron (MLP)-based radiation error correction model was developed using environmental parameters as inputs, achieving a root mean square error (RMSE) of 0.051 °C and a mean absolute error (MAE) of 0.043 °C. After correction, the correlation coefficient between Pt100 probe measurements and reference values reaches 0.999, demonstrating the potential of the proposed approach for high-accuracy near-surface air temperature observations.