Background
- Definition
One of the environmental problems that emerged as a result of urbanization and industrialization. The phenomenon that the average temperature of urban areas is higher than that of rural areas by 0.3 °C to 10 °C.
- Factors affecting the UHI
The most important cause of the UHI is urbanization. By urbanization, the constant increase in hard and heat absorbing surfaces, the density of our cities, and the reduction in natural vegetation are the main factors to the heat island effect. The cities of today continue to increase in size and breadth. It causes urban sprawl; a phenomenon in which the suburbs of a large city develop randomly and disorderly. Urban sprawl is responsible for the increase in heat waves, and sprawl more often leads to extreme heat waves compared to compact metropolises.
And, the regional atmospheric and geographic conditions are a key determinant of the UHI effect and its intensity in cities. For example, In atmospheric conditions, there are air pollution, climatic conditions, and seasonal variations. And in geographic conditions, there are geographic features, land use conditions.
fig. Process of UHI
Ref. The Urban Heat Island Effect, its Causes, and Mitigation, with Reference to the Thermal Properties of Asphalt Concrete
1. Urban Heat Island(UHI)
WRF is a state-of-the-art atmospheric modeling system designed for both meteorological research and numerical weather prediction. It offers a host of options for atmospheric processes and can run on a variety of computing platforms. WRF excels in a broad range of applications across scales ranging from tens of meters to thousands of kilometers.
fig. WRF ARW Modeling System Flow Chart
ref. 관측과 기상모델을 이용한 춘천지역 도시열섬현상 연구,
2. WRF
3. WRF Model Physics Options
Options to control the physical mechanism of WRF. There are Micro Physics, PBL Physics, Cumulus Physics, Radiation Options, Land Surface, Shallow Convection, surface Layer, Urban Physics, Ocean Options, Other Options, LES, WRF Specialty Systems.
We used second option of Urban Surface Options (sf_urban_physics), which is about Building Environment Parameterization(BEP) and Building Energy model(BEM). The advantage of BEM is that it computes the evolution of the indoor building temperature as a function of energy production and consumption in the building, the radiation coming through the windows, and the fluxes of heat exchanged through the walls and roofs as well as the impact of the air conditioning system. This evaluation exercise is significant since indoor temperatures were recorded.
NCL is an interpreted language designed specifically for scientific data analysis and visualization. NCL has robust file input and output. It can read and write netCDF-3, netCDF-4 classic, netCDF-4, HDF4, binary, and ASCII data. It can read HDF-EOS2, HDF-EOS5, GRIB1, GRIB2, and OGR files (shapefiles, MapInfo, GMT, Tiger). It can be built as an OPeNDAP client. Currently, the NCL has a 6.6.2 version available.
4. NCL