复杂条件下湍流通量的观测与分析

Turbulence Flux Measurements under Complicated Conditions

随着气候与环境问题的突出,地球生态系统与大气间的CO2、水汽和能量交换引起更大关注。全球通量网和其它研究计划已在不同地区建立了大量通量站;并主要利用涡动相关方法进行通量的观测与分析。许多通量站设在地形起伏、斑块植被地区,且由于长期连续运转,不可避免地会遇到许多不利气象条件。国内各部门应用的涡动相关方法通量观测系统已有数百套。此方法似乎简单,而较准确的有代表性的通量取得却涉及许多问题。国外近10年来有关研究很活跃,国内则显得相对薄弱。仪器和台站很多,却缺乏合乎国际规范的处理程序和质量控制体系,影响到资料共享和合作研究。应根据国际最新进展和部分台站资料,在做成较规范的湍流资料处理程序的基础上,建立包括通量源区分析的质量控制与保证系统。对地形和植被都较复杂的情况,结合国际上几个较典型的通量站和国内祁连山大野口等通量站特点,做了简要介绍。

With the increasing awareness of environmental problems, the interest in carbon dioxide, water vapor, momentum and energy fluxes between terrestrial ecosystem and atmosphere has increased rapidly since last one or two decades. The need for measuring turbulent fluxes over different surfaces and under varying weather condi- tions is indispensable for the discussion of global change. Global FLUXNET and other research programs have built a large number of flux stations all over the world with using eddy covariance method as the predominant technique in the fluxes measurement and analysis. There have been now over a few hundreds of relevent measurement systems in China. Eddy covariance method seems simple. However, to obtain rather accurate and representative fluxes is dependent on many issues, particularly in difficult conditions. Eddy covariance method is a basic principle and appli- cation of atmospheric boundary layer meteorology. Compared to international progresses, there have been less reler- ant researches in China in recent years in such fields as the establishment of standard data processing and data quality control / quality assessment systems, and particularly the challenge for fluxes measurement in complex terrain, patched vegetation, and unfavorable meteorological conditions. A data processing system based on recommendations of FLUXNET under simpler conditions, needs to be built at first. Besides, due to more complicated （difficult） conditions in the world, there is a great need to widen the application of the eddy covariance flux measurement technique to complex surfaces. Recently, two tasks are in progress ： （ 1 ） To clarify the terrain effects through careful investigation from flat to rolling terrain and to more complex landscape; （2） To better understand the flux exchange at night and week turbulence conditions by investigating ＂intermittent turbulence＂ and ＂flow separation＂ at first, for instance, at Dayekou flux station in Qilian mountain, west China.