A canopy layer model and its application to Rome.

An urban canopy layer model based on four energy balance equations at ground level and at building level was developed to simulate and describe the urban climate and the heat storage in an urban setting. Thermal and radiative characteristics of urban and rural surfaces as well as atmospheric parameters related to the general synoptic conditions were used as data input. In addition, buildings were modelled as parallelepipeds and the hysteresis of materials was taken into account. The model provides as output skin temperature of buildings, air temperature and humidity within the canopy layer and hence the mean surface temperature and the air temperature at 2 m above surface. The latter parameter was used for the comparison with in situ temperature observations. The model was applied to Rome in radiative summer and winter episodes. The results, which agree with observations, show that the Urban Heat Island (UHI) is a nocturnal phenomenon, present both in winter (the greatest difference between urban and rural temperatures is about 2 degrees C) and summer (the temperature difference is about 5 degrees C), mainly resulting from the urban geometry and the thermal properties of materials. The anthropogenic heat does not play an important role in the UHI development. A monthly nocturnal behaviour of temperature differences between urban and surrounding rural areas shows that the maximum mean value of 4.2 degrees C occurs in August. Moreover, the parks in the city centre, where temperatures are lower, define two distinct heat islands, east and west.

[1]  C. S. B. Grimmond,et al.  An urban canyon energy budget model and its application to urban storage heat flux modeling , 1998 .

[2]  Hye-Sook Park.  Features of the heat island in seoul and its surrounding cities , 1986 .

[3]  B. W. Atkinson.  Numerical Modelling of Urban Heat-Island Intensity , 2003 .

[4]  Ian Simmonds,et al.  Associations between varying magnitudes of the urban heat island and the synoptic climatology in Melbourne, Australia , 2000 .

[5]  T. Oke.  The energetic basis of the urban heat island , 1982 .

[6]  David J. Sailor,et al.  Simulated Urban Climate Response to Modifications in Surface Albedo and Vegetative Cover , 1995 .

[7]  Jong‐Jin Baik,et al.  Daily maximum urban heat island intensity in large cities of Korea , 2004 .

[8]  T. Oke,et al.  Turbulent Heat Fluxes in Urban Areas: Observations and a Local-Scale Urban Meteorological Parameterization Scheme (LUMPS) , 2002 .

[9]  J. Monteith,et al.  Principles of Environmental Physics , 2014 .

[10]  A. Lavagnini,et al.  Evidence of the urban heat island in Rome by climatological analyses , 1982 .

[11]  Juan Pedro Montávez,et al.  A study of the urban heat island of Granada , 2000 .

[12]  Gerald Mills,et al.  BUILDING DENSITY AND INTERIOR BUILDING TEMPERATURES: A PHYSICAL MODELING EXPERIMENT , 1997 .

[13]  Krzysztof Fortuniak,et al.  Temporal and spatial characteristics of the urban heat island of Łódź, Poland , 1999 .

[14]  David A. Robinson,et al.  Mesoscale aspects of the Urban Heat Island around New York City , 2003 .

[15]  T. Oke.  The urban energy balance , 1988 .

[16]  A. Slingo,et al.  On the shortwave radiative properties of stratiform water clouds , 1982 .

[17]  L. Kalkstein,et al.  Progress in heat watch-warning system technology , 2004 .

[18]  Dario Camuffo,et al.  The climate of Rome and its action on monument decay , 2001 .

[19]  Timothy R. Oke,et al.  An objective urban heat storage model and its comparison with other schemes , 1991 .

[20]  A SIMPLE LAND SURFACE PROCESS MODEL FOR USE IN CLIMATE STUDY , 1989 .

[21]  J. Unger,et al.  A multiple linear statistical model for estimating the mean maximum urban heat island , 2003 .

[22]  Jong-Jin Baik,et al.  Maximum Urban Heat Island Intensity in Seoul , 2002 .

[23]  David J. Sailor,et al.  A top-down methodology for developing diurnal and seasonal anthropogenic heating profiles for urban areas , 2004 .

[24]  Roger A. Pielke,et al.  Temporal Fluctuations in Weather and Climate Extremes That Cause Economic and Human Health Impacts: A Review , 1999 .

[25]  I. D. Watson,et al.  Simulation of surface urban heat islands under ‘ideal’ conditions at night part 2: Diagnosis of causation , 1991 .

[26]  T. Oke.  City size and the urban heat island , 1973 .

[27]  M. Iqbal.  An introduction to solar radiation , 1983 .