摘要
对沙尘暴期间的近地表0.5 m、1.0 m、8.0 m和16 m的高频风速和温度进行了同步测量,风速和温度的测量频率均为50 Hz。结果表明,4月24日发生在民勤地区的沙尘暴的前2 h为特强沙尘暴,其后为沙尘暴阶段,且在24—27日的沙尘暴期间风速经历了3个增大、平稳和衰减的变化阶段。对第一阶段(24日19时至25日18时)的分析表明,特强沙尘暴期间温度的脉动强度明显增大,其变化原因是温度平流输送引起的,而在其后沙尘暴阶段,温度的均值和脉动强度的变化则基本上是辐射变化导致的。对温度脉动的概率密度计算结果表明,沙尘暴期间温度脉动服从高斯分布,说明它不受沙尘颗粒的影响;而温度脉动的谱分析表明,在低于1 Hz的频率范围内证实了浮力标度区的存在,当频率高于1 Hz时分析表明,夜间和正午的温度谱有明显区别。
Near surface wind velocity and temperature at 0.5 m, 1.0 m, 8.0 m and 16 m were measured during a dust storm in Minqin in April 24, 2010, and the measuring frequency of wind velocity and temperature was all 50 Hz. Measurement results show that the dust storm presented a severe dust storm type during the first two hours, then into dust storm type. The wind speed during April 24 to 27 underwent three stages which contained an increasing period, a contemporary stable period and a decreasing period. Analysis of the wind and temperature of the first stage （from 19：00 of April 24 to 18：00 of the next day） showed that the fluctuation of temperature increased sharply during the severe dust storm period, the reason for that was the transportation of temperature caused by horizontal advection, while the variations of the mean and fluctuation intensity of temperature in the following dust storm period were basically caused by radiation change. Calculation results showed that the probability distribution of temperature fluctuation was Gaussian distribution, indicating that the dust particles had no influence on the distribution of temperature. Spectrum analysis confirmed the existence of a buoyancy scaling region in the frequency range below 1 Hz, either at night or daytime; while the temperature spectra were apparently different at night and day for the frequency higher than 1 Hz.
出处
《中国沙漠》
CSCD
北大核心
2011年第3期649-654,共6页
Journal of Desert Research
基金
国家重点基础研究发展规划项目(2009CB421304)
国家自然科学基金项目(10872082)
兰州大学"中央高校基本科研业务费专项资金"重点项目(lzujbky-2009-161)共同资助
关键词
沙尘暴
功率谱
概率分布
超声风速仪
dust storm
power spectrum
probability distribution, sonic anemometer
