Abstract:Based on multi-source observation data during January-March in 2019, the spatio-temporal distribution characteristics of temperature and wind in Zhangjiakou Olympic Area for the Beijing 2022 Olympic and Paralympic Winter Games are analyzed, especially for their diurnal variations under different synoptic backgrounds. It is shown that the characteristics of temperature and wind are affected both by differences in solar radiation and topographic altitudes. Additionally, the diurnal temperature range in the basin or valley, where temperature inversion phenomena are frequently observed, is significantly larger than that on the mountain top. Meanwhile, temperature inversion intensity is closely related to daily temperature changes and background winds, and the extent of temperature inversion tends to be deeper as environmental wind speed decreases. On the other hand, diurnal variations of wind speed can be clearly seen in the studied area. Winds tend to strengthen in the daytime and reach their peaks in the afternoon, and minimum winds appear at night on average. Local and thermally-driven circulations are dominant under weak synoptic patterns. An obvious shift in wind direction between day and night can be seen in Guyangshu Basin but not in Genting Snow Park. At the same time, cold air tends to accumulate at the basin bottom on nightfall and bring temperature inversion phenomena in the basin, which usually reach their peaks before sunrise and weaken or disappear rapidly after sunrise under weak synoptic circumstances. It is observed that the extent of temperature inversion in Guyangshu Basin is much greater than that in Genting Snow Park. However, there seems to be no diurnal changes in wind direction in both Guyangshu Basin and Genting Snow Park under the influence of cold air, and temperature also decreases monotonously with the increase of altitudes in such a condition.