The diversity of small lakes' (size < 50 km) configurations, sizes, surrounding terrain, and land use combined with relative sparsity of observations complicates the observational evaluation of the lake breezes (LB) that are induced by these lakes. In the present article observational data obtained from available documents, data archives, and special projects were surveyed to suggest characterization of the LB features. The observational survey was complemented by conceptual evaluations. A preliminary generalization of the LB intensity and inland penetration in relation to the surrounding land use was inferred. The conceptual evaluation suggested that for a given lake width the prime factor affecting the LB intensity is the magnitude of the surface sensible heat flux over the surrounding land. Cooling related to the lake water temperature was indicated to have usually a secondary effect on the LB intensity for small lakes. Surface observations implied that the onshore penetration of the LB by the early afternoon hours is typically less than the characteristic width of the lake. Lower atmosphere observations indicated that the vertical extent of the LB may reach several hundred meters. Implications of the observed LB features in support of characterization of the real-world vegetation breeze are discussed. IIP

Shelterbelts or windbreaks have been used for centuries to reduce wind speed, to control heat and moisture transfer and pollutant diffusion, to improve climate and environment, and to increase crop yields; but only within the last few decades have systematic studies considered the aerodynamics and shelter mechanisms of shelterbelts and windbreaks. This is a review of recent modeling and numerical simulation studies as well as the mechanisms that control flow and turbulence around shelterbelts and windbreaks. We compare numerical simulations with experimental data and explain the relationships between sheltering effects and the structure of shelterbelts and windbreaks. We discuss how and why the desired effects are achieved by using numerical analysis. This chapter begins with the derivation of a general equation set for porous shelterbelts and windbreaks; the numerical model and simulation procedure are developed; unseparated and separated flows are predicted and characterized; the momentum budget and This article has been accepted for publication by Annual Reviews in a revised form. 23shelter mechanisms are analyzed; the effects of wind direction, density, width, and three dimensionality of shelterbelt structure on flow and turbulence are systematically described.Recent modeling and simulation of heat flux and évapotranspiration also are summarized.Finally, we discuss use of high-performance distributed and parallel computing as well as clusters of networked workstations to enhance performance of the model applied to simulations of shelterbelts and windbreaks.

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