Urban Environment and Extreme Events- a perspective from the North Eastern United States.

Abstract:

Urban environments amplify the intensity and impact of extreme events. The intensification is the result of unique surface-atmosphere interactions that dictate and define urban climate. The aggravated impacts are related to the design and organization of various urban systems. Our talk here will focus on how the urban microclimate characteristics that include boundary layer development, partitioning of the surface energy budget and urban heat island effect impact various extreme events. Our past work has revealed the presence of thermal internal boundary layers during convective periods that will potentially amplify the impact of extreme heat, precipitation and poor air quality episodes. The storage heat flux - a secondary term in the surface energy budget over non-urban canopies - plays a primary role in urban areas. It is in fact the most dominant term in the urban environment that is responsible for prolonging heatwave episodes. The talk will also focus on how these dynamic modifications to the microclimate impact various urban systems that include energy, health and transportation sectors. The results presented here are from various field and numerical experiments that were conducted in the North Eastern United States during the last decade.