不同下垫面温度和湿度湍流谱特征研究

利用相同探测设备、相同试验方法在戈壁、草原、郊区和城郊等不同下垫面开展的多次重复湍流观测实验资料，采用相同的湍流数据采集和处理方法，研究了不同下垫面温度和湿度湍流谱特征。研究表明：归一化的温度和湿度谱的高频段满足-2/3幂次律，低频段谱曲线相对集中在较窄的范围内，不呈现随稳定度参数z/L规则散布；较湿润地区的湿度谱曲线与温度谱十分相似，谱形一致；平坦地形谱曲线比粗糙下垫面要开阔、平缓；粗糙下垫面的谱曲线较为尖锐，“拐点”对应的无因次频率约为0.1；高粗糙度下垫面的高频段谱曲线高于平坦地形，说明高粗糙度地区的局地湍流耗散较强。戈壁下垫面的低频段湿度谱数值明显高于其他地区。研究还发现，稳定层结下，由于大尺度过程和重力波的共同作用，在分析双峰数据时应慎重。

Spectral Characteristics of Atmospheric Turbulence over Various Surface Conditions

A comprehensive study of spectral characteristics of atmospheric turbulence over different surface conditions,including the Gobi desert,grassland,suburban and urban area,outskirts was carried out.The turbulent data were collected by the same personnel,sound instrumentation,turbulent data acquisition system and turbulent processing system.Results show that the lower frequency portion of temperature and humidity spectra reveals a flatter peak than that at the upper level of urban area.Spectra curves do not reveal a regular changing tendency according to their stability conditions,but converge to a very narrow bend in both the lower and higher frequency portions.The value of humidity spectra in low-frequency in Gobi is higher than that in other sites.The humidity characteristics are similar with temperature in humid regions.