塔克拉玛干沙漠腹地起伏地形近地层微气象特征

利用2018年10月8日至2019年1月31日塔克拉玛干沙漠腹地起伏地形上高大沙垄高点和低点的温度、相对湿度、风速和大气压同步观测资料,对比分析沙漠起伏地形上秋冬季的微气象特征。结果表明:塔克拉玛干沙漠腹地高大沙垄造成的地形起伏,使得沙垄高点和沙垄低点气温、比湿和风速日变化差异明显。沙垄高点和沙垄低点气温差异主要体现在夜间,与沙漠腹地夜间存在逆温现象有关,表现出沙垄高点气温明显高于沙垄低点,观测期气温差异平均值为6.6 ℃。沙垄低点气温日较差高于沙垄高点。2018年10、11、12月,气温随高度变化出现逆温现象与沙垄高点气温高于沙垄低点气温在时间上相互对应。两个站点比湿较小,平均比湿分别为0.68 g·kg^-1和0.99 g·kg^-1。比湿日变化趋势随季节发生显著变化,主要与大气稳定度增加、冬季水汽增多及夜间逆湿现象逐渐显著相关。地形位置较高的沙垄高点风速比沙垄低点大,风速差异主要体现在夜间。2018年11月2、14、15、20日和2019年1月30日,沙垄高点风速维持在1.9~4.6 m·s^-1,平均3.2 m·s^-1,沙垄低点风速维持在0.8~4\^5 m·s^-1,平均2.5 m·s^-1。

The surface layer micrometeorological characteristics of fluctuated surface in the hinterland of Taklimakan Desert

Based on the synchronous observation data of air temperature, relative humidity, wind speed and air pressure on the high and low points of high sand ridges in the hinterland of Taklimakan Desert from October 8, 2018 to January 31, 2019. We compared and analyzed the micrometeorological characteristics of autumn and winter on the undulating terrain of desert.The results show that the variation of topography caused by the high sand ridges makes the diurnal variation of air temperature, specific humidity and wind speed obvious between the high point of the sand ridge and the low point of the sand ridge in the hinterland of the Taklimakan Desert. The temperature of sand ridge high point and sand ridge low point difference is mainly related to the phenomenon of temperature inversion at night in the hinterland of desert,which shows that the temperature at the sand ridge high point is obviously higher than that of the sand ridge low point, and the average temperature difference during the observation period is 6.6 ℃.The daily range of temperature the low point of the sand ridge is higher than the high point of the sand ridge.In October, November and December 2018 the inversion phenomenon of air temperature with height corresponds to the time when the temperature at the high point of the sand ridge is higher than that at the low point of the sand ridge. The specific humidity of the two sites was smaller, and the average specific humidity was 0.68 g·kg^-1 and 0.99 g·kg^-1 respectively. The diurnal variation trend of specific humidity varies significantly with the season, which is mainly related to the increase of atmospheric stability, the increase of water vapor in winter and the phenomenon of reverse humidity at night. The wind speed at the high point of the sand ridge with higher terrain position is larger than that at the low point of the sand ridge, and the difference of wind speed is mainly reflected in the night. The wind speed was maintained between 1.9 and 4.6 m·s^-1 at the high point of the sand ridge, with an average wind speed of 3.2 m·s^-1. The low point wind speed of sand ridge is between 0.8 and 4.5 m·s^-1, and the average wind speed is 2.5 m·s^-1 on November 2, 14, 15, 20 and January 30, 2018.