Comparison of Ventilated and Unventilated Air Temperature Measurements in Inland Dronning Maud Land on the East Antarctic Plateau

• Published in: Journal of atmospheric and oceanic technology 2021-12, Vol.38 (12), p.2061-2070
• Main Authors: Morino, Shohei, Kurita, Naoyuki, Hirasawa, Naohiko, Motoyama, Hideaki, Sugiura, Konosuke, Lazzara, Matthew, Mikolajczyk, David, Welhouse, Lee, Keller, Linda, Weidner, George
• Format: Article
• Language: English
• Subjects: Air temperature; Antarctic radiation; Antarctic temperatures; Automatic weather stations; Bias; Cylinders; Errors; Heating; Mean temperatures; Plateaus; Radiation; Radiative heating; Regression models; Relay stations; Sensors; Shields; Short wave radiation; Sunlight; Surface temperature; Surface temperature measurements; Systematic errors; Temperature; Temperature data; Temperature measurement; Wind; Wind speed; Winds
• ISSN: 0739-0572; 1520-0426
• DOI: 10.1175/JTECH-D-21-0107.1

Surface temperature measurements with naturally ventilated (NV) sensors over the Antarctic Plateau are largely subject to systematic errors caused by solar radiative heating. Here we examined the radiative heating error in Dronning Maud Land on the East Antarctic Plateau using both the newly installed automatic weather stations (AWSs) at NDF and Relay Station and the existing AWSs at Relay Station and Dome Fuji. Two types of NV shields were used in these AWSs: a multiplate radiation shield and a simple cylinder-shaped shield. In austral summer, the temperature bias between the force-ventilated (FV) sensor and the NV sensor never reached zero because of continuous sunlight. The hourly mean temperature errors reached up to 8°C at noon on a sunny day with weak wind conditions. The errors increased linearly with increasing reflected shortwave radiation and decreased nonlinearly with increasing wind speed. These features were observed in both the multiplate and the cylinder-shaped shields. The magnitude of the errors of the multiplate shield was much larger than that of the cylinder-shaped shield. To quantify the radiative errors, we applied an existing correction model based on the regression approach and successfully reduced the errors by more than 70% after the correction. This indicates that we can use the corrected temperature data instead of quality controlled data, which removed warm bias during weak winds in inland Dronning Maud Land.