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.

在LITFASS-2003实验期间，已经收集了关于大气边界层（ABL）结构（ABL）结构的全面实验数据集。这项运动是在德国气候研究计划（DEKLIM）的EVA握把（网格和像素量表）项目中实现的。测量值包括14个表面通量站的操作，在99 m塔上的两个涡流系统，三个大孔径闪烁体（LAS）的操作以及使用Helipod的35个低级飞行的性能，这是一架直升机携带的湍流探针。在EVA握把内（2004年到期）中，已经在确定面积的蒸发值的情况下进行了分析。目前的提案我们旨在进一步分析LITFASS-2003数据集，以消除有关我们对湍流ABL结构的理解和过程中的湍流ABL结构的理解，以消除现有的DEFIC。应调查以下问题：1。地形异质性，异质土地使用和异质大气在ABL结构上的相对重要性是什么？2。在哪些条件下以及在异质地面上的ABL中出现水平混合的水平混合？3。在不同的空间尺度下的异质性效应能否解释非关闭的表面能平衡？4。不同的时间尺度，标量相似性和热诱导的二次循环如何影响湍流测量值，以及大气模型中湍流通量参数的影响？对实验数据的分析将通过已经完成的大型模拟（LES）运行并在新的LES进行了特定的研究中进行专门研究和专门启动的研究，从而支持了实验数据的分析。最后，应得出对测量，数据分析和建模策略的影响，包括建议在异质景观中适当设置和位置表面层和轮廓测量系统的建议。实验策略应通过一种方法来补充，以适当纠正局部湍流通量，以实现表面能量平衡的关闭。