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The Effect of Land Surface Heterogeneity on the Atmospheric Boundary-Layer Structure and Measurements

地表非均质性对大气边界层结构的影响及测量

基本信息

批准号：
117404101
负责人：
Professor Dr. Jens Bange
金额：
--
依托单位：
Institut für Meteorologie und Klimatologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2009
资助国家：
德国
起止时间：
2008-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/117404101?language=en
关键词：
Effect Land Surface Heterogeneity Atmospheric

项目摘要

An comprehensive experimental data set on the structure of the atmospheric boundary layer (ABL) over a heterogeneous land surface has been collected during the LITFASS-2003 experiment. This campaign was realised within the EVA GRIPS (Evaporation at Grid and Pixel Scale) project of the German Climate Research Program (DEKLIM). Measurements included the operation of 14 surface flux stations, two eddy-covariance systems at a 99 m tower, three large-aperture scintillometers (LAS) and the performance of 35 low-level flights using the Helipod, a turbulence probe carried by a Helicopter. Within EVA GRIPS (which expired in 2004), the experimental data have been analysed with respect to the determination of area-averaged values of evaporation.With the present proposal we aim at a further analysis of the LITFASS-2003 data set in order to remove existing deficits concerning our understanding of the turbulent ABL structure and processes over a heterogeneous land surface. The following issues shall be investigated:1. What is the relative importance of terrain heterogeneity, heterogeneous land use and heterogeneous atmospheric forcing on the ABL structure?2. On which conditions and at which levels does horizontal mixing occur in the ABL over a heterogeneous land surface?3. Can heterogeneity effects at different spatial scales explain the non-closed surface energy balance?4. How do different time scales, scalar similarity and thermally-induced secondary circulations influence turbulent flux measurements, and what are the implications for the parameterisation of turbulent fluxes in atmospheric models?Analysis of experimental data will be supported by a further interpretation of data from Large-Eddy Simulation (LES) runs already completed and by the performance of new LES runs set up specifically in light of our previous findings and specific research aims. Finally, implications for measurement, data analysis and modelling strategies shall be derived, including recommendations for a suitable set-up and siting of surface layer and profile measurement systems in a heterogeneous landscape. The experiment strategy shall be supplemented by a methodology to appropriately correct local turbulent surface fluxes in order to achieve closure of the surface energy balance.

LITFASS-2003 实验期间收集了关于异质陆地表面大气边界层 (ABL) 结构的综合实验数据集。该活动是在德国气候研究计划 (DEKLIM) 的 EVA GRIPS（网格和像素尺度蒸发）项目中实现的。测量包括 14 个表面通量站的运行、99 m 塔上的两个涡流协方差系统、三个大孔径闪烁仪 (LAS) 以及使用 Helipod（直升机携带的湍流探测器）进行的 35 次低空飞行的性能。在 EVA GRIPS（于 2004 年到期）中，对实验数据进行了分析，以确定蒸发的面积平均值。通过本提案，我们的目标是进一步分析 LITFASS-2003 数据集，以消除我们对异质地表上的湍流 ABL 结构和过程的理解中存在的缺陷。应调查以下问题： 1．地形异质性、土地利用异质性和大气强迫异质性对ABL结构的相对重要性是什么？2．在异质陆地表面的 ABL 中，水平混合在什么条件和什么水平上发生？3．不同空间尺度的异质性效应能否解释非封闭表面能量平衡？4．不同的时间尺度、标量相似性和热诱发的二次环流如何影响湍流通量测量，以及对大气模型中湍流通量的参数化有什么影响？对实验数据的分析将得到对已经完成的大涡模拟（LES）运行数据的进一步解释以及根据我们之前的发现和具体研究目标专门设置的新 LES 运行的性能的支持。最后，应得出对测量、数据分析和建模策略的影响，包括对异质景观中表层和剖面测量系统的适当设置和选址的建议。实验策略应辅以适当校正局部湍流表面通量的方法，以实现表面能量平衡的闭合。