Further Evaluation of an Urban Canopy Parameterization using VTMX and Urban 2000 Data
Almost two-thirds of the U.S. population live in urbanized areas occupying less than 2% of the landmass. Similar statistics of urbanization exists in other parts of the world. With the rapid growth of the world population, urbanization appears to be an important issue on environmental and health aspects. As a result, the interaction between the urban region and atmospheric processes becomes a very complex problem. Further understanding of this interaction via the surface and/or atmosphere is of importance to improve the weather forecast, and to minimize the loss caused by the weather-related events, or even by the chemical-biological threat. To this end, Brown and Willaims, (1998) first developed an urban canopy scheme to parameterize the urban infrastructure effect. This parameterization accounts for the effects of drag, turbulent production, radiation balance, and anthropogenic and rooftop heating. Further modification was made and tested in our recent sensitivity study for an idealized case using a mesoscale model. Results indicated that the addition of the rooftop surface energy equation enables this parameterization to more realistically simulate the urban infrastructure impact (Chin et al., 2000). To further improve the representation of the urban effect in the mesoscale model, the USGS land-use data with different resolutions (200 and 30 meters) are adopted to derive the urban parameters via a look-up table approach (Leone et al., 2002; Chin et al., 2004). This approach can provide us the key parameters for urban infrastructure and urban surface characteristics to drive the urban canopy parameterization with geographic and temporal dependence. These urban characteristics include urban fraction, roof fraction, building height, anthropogenic heating, surface albedo, surface wetness, and surface roughness. The objective of this study is to evaluate the modified urban canopy parameterization (UCP) with the observed measurements. Another objective is to demonstrate the deficiency of using limited numbers of single-station meteorological measurements to validate the urban impact in the mesoscale models. The final objective of this study is to assess the value of tracer data in assessing the performance of UCP.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15014255
- Report Number(s):
- UCRL-CONF-204547; TRN: US200803%%654
- Resource Relation:
- Conference: Presented at: Symposium on the Urban Environment, Vancouver, Canada, Aug 23 - Aug 27, 2004
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evaluation of an Urban Canopy Parameterization in a Mesoscale Model
A Sensitivity Study of the Urban Effect on a Regional-Scale Model: An Idealized Case