资源环境科技发展态势分析平台

The effective temperature (ET) is employed to investigate observed changes of thermal comfort conditions over China during the late decades of the historical observational period. ET considers the aggregate effects of temperature, relative humidity, and wind speed to describe the human thermal sensitivity to weather and climate. The data used in the study is the recently produced gridded daily scale dataset CN05.1, which covers the period of 1961-2014 at a resolution of 0.25 degrees latitude by 0.25 degrees longitude. Results show a general increase of ET in both December-January-February (DJF) and June-July-August (JJA). The increase is mostly caused by an increase of temperature and a decrease of wind speed, while the contribution from relative humidity is small. As measured by ET, China is a cold country with many more cold days than hot days. Large decreases of cold days and increases of hot days are found following the increase of ET. The number of comfortable days shows larger values in the warm areas and during the warm seasons. During the analysis period, the number of annual comfortable days shows an increasing trend when considering the China-wide average. However, the number of annual comfortable days during JJA decreases over warm areas.