A simple and efficient procedure for the numerical simulation of wind fields in complex terrain

Abstract

In spite of recent progress in the prognostic numerical simulation of the atmospheric boundary layer, the explicit simulation of turbulent flows in actual complex terrain is generally still very complicated and time consuming for many environmental applications.In an attempt to develop simpler and more efficient application oriented techniques, although less refined, we propose a multi-step procedure for simulating wind fields. Once obtained the necessary meteorological input, the mass-consistent modelling technique is used to perform high-resolution mean wind flow simulations taking into account recent developments in the atmospheric boundary-layer theory. Besides, a procedure based on a generalisation of the local logarithmic law-of-the-wall over complex terrain is used to estimate the effective parameters characterising the simulated wind profiles. Turbulence intensities and spectral properties are then calculated through the estimated effective parameters, in particular through the effective friction velocity parameter. Finally, time series of the instantaneous velocity field are simulated by the Monte Carlo technique. Two applications of the proposed approach are discussed briefly: the first one is related to a coastal area in southern Italy (the Messina Straits), where the construction of the world's longest central span bridge is being planned; the second one corresponds to the flow in a mountainous area in northern Italy (the Albenga Airport).

An advanced stochastic weather generator for simulating 2‐D high‐resolution climate variables

“…This can be achieved by modifying the model parameters using climate data derived from dynamical climate models (i.e., GCMs and RCMs); however, this aspect is not addressed here. AWE‐GEN‐2d is a substantial evolution and combination of four preceding models: (i) AWE‐GEN model [ Curtis and Eagleson , ; Ivanov et al ., ; Fatichi et al ., ]; (ii) STREAP model [ Paschalis et al ., ]; (iii) HiReS‐WG model [ Peleg and Morin , ]; and (iv) WINDS model [ Burlando et al ., ]. The WG structure is presented in the following sections together with an example where the model is calibrated and tested: the Engelberg region, an area of complex topography located in the Swiss Alps.…”

Monitoring, cataloguing, and weather scenarios of thunderstorm outflows in the northern Mediterranean

“…This semi-automated procedure involves a suitable mix of systematic quantitative controls and qualitative expert judgments. The quantitative controls are based on the comparison between the detected values of the gust factors, G 60 , G 10 , G 1 , and their reference values, G 0 60 , G 0 10 , G 0 1 , evaluated by means of numerical simulations (ESDU, 1993;Burlando et al, 2007Burlando et al, , 2013 assuming that intense wind speeds occur in neutral atmospheric conditions during synoptic extra-tropical cyclones with stationary Gaussian properties. Conceptually, a wind event is labelled as an extra-tropical cyclone if the ratios G 60 /G 0 60 , G 10 /G 0 10 , G 1 /G 0 1 are small.…”

Monitoring, cataloguing and weather scenarios of thunderstorm outflows in the Northern Mediterranean

“…The quantitative controls are based on the comparison between the detected values of the gust factors, .% , $% , $ , and their reference values, .% % , $% % , $ % , evaluated by means of numerical simulations (ESDU, 1993;Burlando et al, 2007; assuming that intense wind speeds occur in neutral atmospheric conditions during synoptic extra-tropical cyclones with stationary Gaussian properties. Conceptually, a wind event is labeled as an extra-tropical cyclone if the ratios .% / .% % , $% / $% % , $ / $ % are small.…”