黄土高原复杂地形上高质量湍流通量数据获取方法  

Method of acquiring high-quality surface turbulent fluxes over the Loess Plateau

作　　者：苑广辉[1] 张镭[1] 李遥[1] 梁捷宁[1] 

机构地区：[1]半干旱气候变化教育部重点实验室,兰州大学大气科学学院,兰州730000

出　　处：《地球物理学报》2016年第6期1971-1982,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41475008);国家重大科学研究计划项目(2012CB955302)资助

摘　　要：利用兰州大学半干旱气候与环境观测站（Semi-Arid Climate and Environment Observatory of Lanzhou University,SACOL）湍流观测资料,分析了二次坐标旋转（double rotation,DR）、平面拟合（planar fit,PF）和分风区平面拟合（fetch planar fit,FPF）在复杂地形上的适用性,总结出一套适用于SACOL的总体湍流特征参数化方案.经过超声虚温订正、坐标旋转、空气密度脉动订正以及平稳性检验、总体湍流特征检验、总体质量分级处理,摩擦速度（u＊）、感热通量、潜热通量、CO2通量高质量数据所占比例分别为45%-62%、66%-68%、62%-65%、52%-54%.采用DR得到的高质量数据比例与采用PF相比,u＊提高了17%,后三种通量略降低2%-3%.PF和FPF两种结果的差别主要体现在u＊上,只考虑主导风向数据DR得到的u＊质量仍最好.综合兼顾数据质量和计算工作量,在复杂地形上处理湍流观测资料的最优坐标旋转方法是DR.The eddy covariance（EC）technique measuring the turbulent exchanges of heat,moisture,CO2 and momentum between surface and atmosphere has been used widely.However,the use of EC is based on some assumptions which do not exist in practice.So the results are not accurate without necessary corrections.Using data collected at the Semi-Arid Climate and Environment Observatory of Lanzhou University（SACOL）,this work studies a method of acquiring high quality surface turbulent flux.In this approach,eddy covariance data processing includes eliminating despikes,coordinate rotations,sonic temperature correction,and WPL correction（correction for density fluctuations）.Double rotation and planar fit are used to do coordinate rotations.The fluctuations of sonic temperature include the effect of humidity on the speed of sound,and should be converted into actual temperature.WPL correction was required to latent heat flux and CO2 flux for the density effects due to heat and water vapor transfer on turbulent flux measurements.Quality control is performed by the stationarity test,integral turbulent characteristics（ITC）test and overall quality is controlled to permit selecting high quality data.The results show that sonic temperature correction decreases sensible heat flux byabout 7.3% when using DR,but 5.9% when using PF.The stability can influence the results of sonic temperature correction.WPL increases latent heat flux by 7.4% and decreases CO2 flux by72.2%,respectively.Three coordinate rotations have great influence on momentum but little on scalar fluxes.The values of u＊ obtained from DR and PF are decreased by 6% and 3%,respectively.Only considering the dominant wind direction,the wind direction has no relationship with the correction of u＊ by DR which reduces u＊ by 5%.As the turbulent exchange strengthened（u＊ 0.3m·s ^-1）,PF and FPF gradually exhibit that the corrected values in southeast are bigger than the northwest area,PF in the southeast wind area increases u＊by 9.23%,yet decreases 3.86% in the

关 键 词：黄土高原 涡动相关 通量订正 质量控制 分风区平面拟合 

分 类 号：P425.2[天文地球—大气科学及气象学]