I-Tree Temperature: An Object Oriented Model on Urban Microclimate Simulation

Abstract:

Air temperature and humidity are two of the most critical meteorological variables in relation to biological and hydrological processes, human thermal comfort, ecosystems, and energy consumption on heating and cooling. Yang et al. (2013) developed a physically-based analytical spatial air temperature and humidity (PASATH) model to simulate microclimate of urban area. This model can provide spatial time series maps of air temperature, humidity, latent heat flux, and sensible heat flux in spatial resolution of one hundred meters and temporal resolution of one hour. PASATH performed satisfactorily given its intended simplicity and low requirement on the inputs. The USDA Forest Service and the Davey Institute developed i-Tree Temperature model based on the PASATH model to complement the strength of the i-Tree suite of tools for urban forest analyses of structure and ecosystem services. The i-Tree temperature model was written in C++ with Objected Oriented Design (OOD). Improved functions were added to improve the simulation of heat flux resistances; new classes were incorporated to better control the inputs and outputs; new model structure was designed to advance the simulation efficiency; inputs formating were optimized to make it more user friendly. The model will be publicly available as a new i-Tree function in 2015 by the USDA Forest Service and the Davey Institute. It can be used to study urban heat island effects and investigate land cover and hydrology based mitigation methods; the simulated spatial maps of air temperature and humidity can provide inputs for other environmental models, including atmospheric models, ecosystem models, and hydrology models, for scientific studies of environmental and human health.