Summary

The goal of Perdigao is to  improve our understanding of flow over complex terrain, including any effects of vegetation and heterogeneity at the surface, with a specific target of improving wind prediction in complex terrain at microscale. Of particular interest is the assessment of wind resources for the wind energy community.  Perdigao will collect a reference data set at an unprecedented spatial resolution, characterizing both the mean and turbulent wind fields in a natural setting. The long-term goal of the Perdigão project is to create numerical models that better represent flow over complex terrain than those currently in common practice. In the European context, the new models are expected to contribute to a new European Wind Atlas. In the US context, the objectives are to create new scientific knowledge and develop better parameterizations for complex terrain processes, with broad impacts of future microscale model developments for wind energy prospecting, flow and dispersion in heterogeneous complex terrain as well as human resources development.

Perdigao will be conducted at a site in central Portugal that has a pair of parallel ridges (with a valley in between) that are quasi-two dimensional. The surface is a mixture of farming areas and patches of eucalyptus for pulp and paper industry, so interactions of a vegetative canopy with the flow is observable with suitable instrumentation. The experiment is named for the local community of Perdigao. A unique aspect of this site is the existence of a single wind turbine (Enercon 2MW; 82m diameter) on one of the ridges. This will allow investigation of both how the turbine power depends on the airflow at the ridge top and how the turbine wake affects local conditions. 

The  field deployment will utilize state-of-the-art tower and remote sensing instrumentation to provide an extensive, high-resolution dataset for studies of complex terrain meteorology. Included will be a number of scanning Doppler lidars, a network of short and tall towers throughout the ridges and valley with sonic anemometers and other instrumentation at multiple levels, a number of remote sensors (Sodar, RASS, wind profilers, water vapor DIAL, microwave radiometers, and profiling lidars.  Additionally there will be balloon-borne instrumentation including radiosondes and tethersondes.