Microscale Warming due to Poor Ventilation at Surface Observation Stations

Abstract

AbstractScreen-level air temperature measurements at surface observation stations are influenced by local-site-scale factors. These local influences may affect global-scale climate change studies. This study investigated the influence of surface obstacles on air temperature measurements at the screen level at climate observation stations in Japan. Screen-level air temperature was measured simultaneously at two neighboring sites (<100 m apart) that differed in terms of their openness. Daytime air temperature was 0°?1°C higher at the narrower site, and theoretical analysis revealed that this warming was caused by poor ventilation. At night, poor ventilation at the narrower site caused the air temperature to be 0°?0.2°C lower, which was demonstrated experimentally and by theoretical analysis. The range of temperature changes due to site narrowing shown in this study is not negligible in climate change studies. Guidelines for site maintenance and metadata recoding were consequently proposed in terms of site openness.