HR: 1340h
AN: A53A-0862    [Abstracts]
TI: Effects of the Sky View Factor on the Nocturnal Cooling Rate of Urban Air Temperature: Numerical Experiments by an Urban Canopy Model
AU: * Tomita, T
EM: tomita@sci.kumamoto-u.ac.jp
AF: Faculty of Science Kumamoto University, Kurokami 2-39-1, Kumamoto, 860-8555 Japan
AU: * Tomita, T
EM: tomita@sci.kumamoto-u.ac.jp
AF: Frontier Research Center for Global Change JAMSTEC, Kanazawa-ku, Showa-machi 3173-25, Yokohama, 236-0001 Japan
AU: Imasato, Y
EM: 1carp@maui.sci.kumamoto-u.ac.jp
AF: Graduate School of Science and Technology Kumamoto University, Kurokami 2-39-1, Kumamoto, 860-8555 Japan
AB: The diurnal variation of air temperature is different between in urban and rural areas. In urban area, the nocturnal cooling rate is moderate and constant until sunrise, while in rural area, the rate is large from sunset to around 20 Local Time (LT) and is changed to be small from 20 LT to sunrise. Using a simple urban canopy model, this work examines the physical mechanisms how such differences appear between in urban and rural areas. In particular, this work focuses on the small sky view factor and the large thermal inertia in urban area. The numerical experiments identify that the sky view factor is responsible for the differences appearing in the nocturnal cooling rate, while the thermal inertia controls the diurnal range of temperature rather than the cooling rate. The roles and contribution of anthropogenic heat in urban area would further be discussed at the meeting.
DE: 3329 Mesoscale meteorology
DE: 3307 Boundary layer processes
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting