Heterogeneity-Induced Heat-Flux Patterns in the Convective Boundary Layer: Can they be Detected from Observations and is There a Blending Height?—A Large-Eddy Simulation Study for the LITFASS-2003 Experiment
Heterogeneity-Induced Heat-Flux Patterns in the Convective Boundary Layer: Can they be Detected from Observations and is There a Blending Height?—A Large-Eddy Simulation Study for the LITFASS-2003 Experiment
复制标题
对流边界层中的非均质性引起的热通量模式：可以从观测中检测到它们吗？是否存在混合高度？ LITFASS-2003 实验的大涡模拟研究
DOI：
10.1007/s10546-013-9822-1
复制
发表时间：
2003
影响因子：
4.3
通讯作者：
Raasch S
中科院分区：
文献类型：
--
作者：
Sühring M;Raasch S
了解对流边界层（CBL）是如何混合下的非均匀表面强迫是至关重要的面积平均湍流测量的解释。为了确定的高度和程度，一个复杂的异质表面影响CBL，大涡模拟（LES）两天的LITFASS-2003实验代表两种不同的风制度进行。空间滞后相关分析表明，湍流热通量依赖于整个CBL，包括卷吸层的规定的表面通量模式。这些发现引发了一个问题，即由表面异质性引起的信号是否可以通过机载系统测量。为了研究这个问题，根据LITFASS-2003期间进行的直升机飞行测量，使用LES进行了虚拟飞行的集合。由此产生的整体平均热通量表明了明确的依赖下垫面的CBL的顶部。然而，在不同的集合运行中的通量测量之间的大的分散被观察到，这是最大的湍流涡旋的采样不足的结果。基于积分长度尺度的随机误差和系统误差并没有显示出如此大的分散性。对于给定的航段长度，至少需要10-15个统计上独立的飞行测量，以给出CBL中不均匀性引起的信号的显著估计。系综平均的需要表明，所观察到的混合CBL中的异质性诱导的信号可以部分归因于不充分的平均。
An understanding of how the convective boundary layer (CBL) is mixed under heterogeneous surface forcing is crucial for the interpretation of area-averaged turbulence measurements. To determine the height and degree to which a complex heterogeneous surface affects the CBL, large-eddy simulations (LES) for two days of the LITFASS-2003 experiment representing two different wind regimes were undertaken. Spatially-lagged correlation analysis revealed the turbulent heat fluxes to be dependent on the prescribed surface flux pattern throughout the entire CBL including the entrainment layer. These findings prompted the question of whether signals induced by surface heterogeneity can be measured by airborne systems. To examine this question, an ensemble of virtual flights was conducted using LES, according to Helipod flight measurements made during LITFASS-2003. The resulting ensemble-averaged heat fluxes indicated a clear dependence on the underlying surface up to the top of the CBL. However, a large scatter between the flux measurements in different ensemble runs was observed, which was the result of insufficient sampling of the largest turbulent eddies. The random and systematic errors based on the integral length scale did not indicate such a large scatter. For the given flight leg lengths, at least 10–15 statistically independent flight measurements were necessary to give a significant estimate of heterogeneity-induced signals in the CBL. The need for ensemble averaging suggests that the observed blending of heterogeneity-induced signals in the CBL can be partly attributed to insufficient averaging.
登录
查看更多内容
基于雷达和原位观测的大气边界层水平卷和单元时空特征
影响因子：
4.3
作者：
F. Lohou;A. Druilhet;B. Campistron
通讯作者：
B. Campistron
DOI：
10.1007/978-3-642-60481-2
发表时间：
1997
期刊：
--
影响因子：
--
作者：
A. Blackadar
通讯作者：
A. Blackadar
影响因子：
4.3
作者：
Beare, RJ;MacVean, MK;Sullivan, P
通讯作者：
Sullivan, P
DOI：
--
发表时间：
2007
期刊：
影响因子：
--
作者：
M. Lothon;F. Couvreux;S. Donier;F. Guichard;P. Lacarrére;D. Lenschow;J. Noilhan;F. Saïd
通讯作者：
F. Saïd
飞机观测非均匀陆地表面热内边界层的发展和对流边界层的缩放
DOI：
--
发表时间：
2004
期刊：
Boundary-Layer Meteorology 111
影响因子：
--
作者：
Strunin;M.A.;T.Hiyania;J.Asanuma;T.Ohata
通讯作者：
T.Ohata