Advancing theory and modeling of land-atmosphere coupling over heterogeneous urban terrain
Abstract
Cities are home for over half of the worldÕs population and are known as heat islands as their temperatures are typically higher than those of the surrounding rural areas. However, how the urban heat island effect is modulated by and interacts with large-scale weather systems, particularly heat waves, is largely unknown, despite of the significant implications for human health, air quality, urban infrastructure, and urban ecosystems. This knowledge gap reflects our poor understanding of urban-atmosphere coupling, which is rooted in the fact that urban areas are often ignored in previous land-atmosphere coupling studies. The proposed research aims to advance theory and modeling of land atmosphere coupling over heterogeneous urban terrain using a combination of observation data, numerical simulations, and mechanistic models. First, a variety of decade-long, publically available observational data sets will be utilized to characterize the impacts of heat waves on urban surface and near-surface climates, the structure of urban boundary layer, and turbulent transport of momentum and heat in the urban boundary layer. In particular, a new data set of hourly temperature profiles in the urban boundary layer will be developed using aircraft data, which will fill the critical gap of observing boundary layer dynamics at diurnal scales. Second, high-resolution (~1 km) and long-term (10 years) numerical simulations will be carried out to assess the performance of a state-of-the-science mesoscale model, the Weather Research and Forecasting (WRF) model, in predicting extreme high-temperature events in cities, and to quantify the effectiveness of heat mitigation strategies. The WRF model simulations will be also used to attribute heat wave-induced warming at the urban surface and in the urban boundary layer, with a specific focus on the influence of heat waves on urban-rural circulations and the horizontal advection of heat across the urban-rural gradient. Third, mechanistic models will be developed and integrated with observational data and numerical simulations to identify and quantify key land-atmosphere coupling mechanisms and feedbacks. Specifically, the breakdown of one-dimensional models and the related scale issue in land-atmosphere coupling over heterogeneous urban terrain will be addressed. The proposed research will fundamentally advance our understanding of land-atmosphere coupling over heterogeneous urban terrain where the traditional, one-dimensional paradigm breaks down. The proposed research will also assess and improve the capability of numerical weather prediction models such as WRF in predicting extreme heat events in urban environments. The findings and outcome from this proposal can be used to inform the design of mitigation and adaptation strategies for enhancing the resilience of the built environment to extreme heat events.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810360
Entities
People
- Dan Li
Organizations
- Army Contracting Command
- Boston University
- United States Army