Large-Eddy Simulation of Atmosphere and Land Interactions over Heterogeneous Surfaces

Research Area:
Atmosphere, Land surface, Turbulence

We have been developing a numerical modeling system, known as LES-ALM, for simulation of heterogeneous atmospheric and land-surface processes on scale of atmospheric large eddies. LES-ALM includes a large-eddy flow model and a land-surface scheme which ensures the adequate representation of atmosphere–land-surface interactions on large-eddy scales. Improvements made to the land-surface scheme include (1) a multi-layer canopy scheme; (2) a method for flux estimates consistent with the large-eddy sub-grid closure; and (3) an appropriate soil-layer configuration. The model has been implemented to the Selhausen-Merken test site and validated with TR32 airborne and ground-based observations (Shao et al. 2013). The rapid large-eddy and surface feedbacks have been investigated by Liu and Shao (2013). The current research focus is on the propagation of land-surface patterns into the atmosphere. A technique has been developed for quantifying land-surface heterogeneity using the information entropy spectrum (IES). IES allows the identification of dominant heterogeneity scales and provides a sound basis for land-surface simplifications and reconstructions in atmospheric models (Hintz et al. 2014). Techniques based on cluster analysis have been under development for investigation of the propagation of surface patterns into the atmosphere (Lennartz-Sassinek et al. 2014).The scale dependencies of heterogeneous atmosphere-land interactions are being investigated from various perspectives (Shao et al. 2014; Liu et al. 2014).

Cooperation partner:

• University of Texas at Austin (USA)
• Georgia Institute of Technology (USA)
• Chinese Academy of Sciences (China)