Flow Regimes of Mesoscale Circulations Forced by Inhomogeneous Surface Heating

• DOI: 10.48550/arxiv.1611.08912
• Publication Date: 2016-01-01
• Authors: Hossain, M. Alamgir; Alam, Jahrul M
• Keywords: Physics - Atmospheric and Oceanic Physics; 13. Climate action; 11. Sustainability; Atmospheric and Oceanic Physics (physics.ao-ph); FOS: Physical sciences; 01 natural sciences; 0105 earth and related environmental sciences

Conference paper, CFD soceity of Canada, Published, in 23rd Annual Conference of the Computational Fluid Dynamics Society of Canada, 2015<br/>Urbanization is one of the extreme process that increases uncertainty in future climate projections. Flow regimes of mesoscale circulations associated with surface heating due to urbanization have been investigated using a wavelet based computational fluid dynamics~(CFD) model. The results of our numerical model have been validated against that of a laboratory model, as well as reference numerical simulations. Characteristics of urban induced circulations have been studied for surface heat flux perturbation ($H_0$) between $28.93$Wm$^{-2}$ and $925.92$Wm$^{-2}$, and the results have been analyzed against available boundary layer measurements under similar physical conditions. Our primary study shows that urban/rural heat flux anomalies introduce strong oscillations in the convective boundary layer (CBL), and transfers a fraction of the turbulent kinetic energy vertically through internal waves. Such results complement previous investigators' hypothesis that temporal oscillations in urban-induced mesoscale circulations are primarily due to a downscale energy cascade. Although a further detailed study is necessary, the present numerical observations provide useful feedback for the impacts of urbanization on regional climate.<br/>