Appendix F Background and Assumptions: Wind Data Interpolation

In the wake of the environmental movement the burgeoning wind energy industry, equipped with a rudimentary understanding of the wind resource and limited socio-economic policies, created today's wind energy paradigm characterised by farms of tower-mounted, 3-bladed, horizontal-axis wind turbines (HAWTs). This research undertaking proposes that a paradigm shift is in order and that commissioning of decentralised, in-situ, urban-scale wind energy conversion devices could assist the industry.

The literature offers a large range of values for the roughness length [z0] with uncertainties as large as 65% , prompting further research into the development of analytical techniques. By the surface descriptions provided in most published tabulations, it becomes apparent that these lengths were primarily based on agricultural parameterisation schemes developed over 20 years ago. Wieringa (1993) provides an extensive review of the results, methodology, and theoretical foundation of 50 comprehensive studies on the roughness of homogeneous terrain types. The development of the UWEP DSS's roughness classification table, including a compilation of the various proposed roughness length categorisation schemes that were considered, is provided in

Boundary-Layer …, 2003

Abstract. Observations of wind statistics within and above a Scots pine forest are compared with those predicted from an analytical second-order closure model. The roughness sublayer (RSL) ef-fects, and the influence of stability on similarity functions, are studied using ...

Journal of Wind Engineering and Industrial Aerodynamics, 2013

The micro-turbine wind market in cities faces significant challenges due to the complexities associated with the urban terrain but, if a renewable solution to increasing energy demand is to be achieved, energy conversion systems where populations are concentrated, that is cities, must be considered. This research evaluates the urban wind resource by employing a physically-based empirical model to link wind observations at a conventional meteorological site to those acquired at urban sites. The approach is based on urban climate research that has examined the effects of varying surface roughness on the wind-field between and above buildings. Here, this is applied to link observations at Dublin Airport, outside the urban area, to those made at an urban and suburban site in Dublin where instruments were placed near roof-level and well above roof height. The log model to describe the vertical wind profile is tested against observations made over the course of a year. It is shown to have sufficient accuracy to assess the potential for micro-turbine energy generation in cities and illustrates that the urban wind resource can be evaluated from measurements made at a nearby site, adjusted for the urban site location.

Boundary-Layer Meteorology, 2007

This study quantifies the processes that take place in the layer between the mean building height and the measurement level of an energy balance micrometeorological tower located in the dense old core of a coastal European city. The contributions of storage, vertical advection, horizontal advection and radiative divergence for heat are evaluated with the available measurements and with a three-dimensional, high-resolution meteorological simulation that had been evaluated against observations. The study focused on a summer period characterized by sea-breeze flows that affect the city. In this specific configuration, it appears that the horizontal advection is the dominant term. During the afternoon when the sea breeze is well established, correction of the sensible heat flux with horizontal heat advection increases the measured sensible heat flux up to 100 W m −2 . For latent heat flux, the horizontal moisture advection converted to equivalent latent heat flux suggests a decrease of 50 W m −2 . The simulation reproduces well the temporal evolution and magnitude of these terms.

Meteorologische Zeitschrift, 2007

Mean seasonal profiles of wind speed, standard deviation of the vertical velocity and turbulence intensity from SODAR measurements in three cities of different size, Moscow, Hanover and Linz, are compared to analytical approximations for the Prandtl and Ekman layer. Typical urban features in the profiles and differences to measurements at rural sites are discussed. Typical urban features are a greater slope in the wind profiles, enhanced turbulence intensities, and a vertical increase in magnitude of the turbulence. The analytical approach proposed by ETLING for the description of the vertical wind profile in the whole boundary layer is amended in the Prandtl-layer part by a correction function for atmospheric stability. The amended profile description turns out to render the best results for the approximation of urban wind profiles within the lowest 500 m above ground.

Meteorologische Zeitschrift, 2007

Mean seasonal profiles of wind speed, standard deviation of the vertical velocity and turbulence intensity from SODAR measurements in three cities of different size, Moscow, Hanover and Linz, are compared to analytical approximations for the Prandtl and Ekman layer. Typical urban features in the profiles and differences to measurements at rural sites are discussed. Typical urban features are a greater slope in the wind profiles, enhanced turbulence intensities, and a vertical increase in magnitude of the turbulence. The analytical approach proposed by ETLING for the description of the vertical wind profile in the whole boundary layer is amended in the Prandtl-layer part by a correction function for atmospheric stability. The amended profile description turns out to render the best results for the approximation of urban wind profiles within the lowest 500 m above ground.

Boundary-layer Meteorology, 2002

Using a mountain meadow as a case study it is the objective of the present paper todevelop a simple parameterisation for the within-canopy variation of the phytoelementdrag (Cd) and sheltering (Pm) coefficients required for Massman's model of momentum transfer by vegetation. A constant ratio between Cd and Pm is found to overestimate wind speed in the upper canopy and underestimate