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METHOD
1. Basic setting
Using 'em_seabreeze2d_x' for setting ideal case in WRF(Weather Research and Forecasting)model
(1) Set the period from 2016-08-10_21:00:00 UTC
to 2016-08-11_21:00:00 UTC (time interval as 1 hour)
(2) Set the city size as 200km.
(3)To create 200 grids which are1000m each, set ‘e_we’ to 200 and ‘dx’ to 1000
(4) In 'namelist.input', change 'sf_surface_physics' to 2, 'mp_physics' to 16 and add 'sf_urban_physics = 1'
(5) Set the constant amount of insolation
2. Case setting
(1) Vary the initial temperature (280K, 290K, 300K) in each case
(2) Use three categories (1:urban, 9:mixed shrubland/grassland, 16:water bodies) in USGS 24 in each case since urban island effect is significantly influenced by geographical surrounding
case 0 _ initial temperature
Urban
(0-199)
Assume the entire grids as ‘urban’ and vary the initial temperature to check whether the initial temperature affects urban heat island effect or not.
case 1 _ initial temperature and geographical surrounding
Grass Urban Grass
(0-19) (20-179) (180-199)
Water Urban Water
bodies bodies
(0-19) (20-179) (180-199)
Assume that grass or water bodies exists on both sides of urban of which length is 160km in each initial temperature(280K, 290K, 300K).
case 2 _ difference in layout with case 1
Grass Urban Grass Urban Grass
(0-19)
(20-89)
(90-109)
(110-179)
(180-199)
Water Urban Water Urban Water
bodies bodies bodies
(0-19)
(20-89)
(90-109)
(110-179)
(180-199)
Assume that grass or water bodies exists in the middle of the grids and on both sides of urban of which length is 140km in each initial temperature(280K, 290K, 300K).
The difference between case 1 and case 2 would be that of layout of grids.
case 3 _ initial temperature and urban land use type
Grass
(0-199)
Water bodies
(0-199)
Assume the entire grids as ‘grass’ or ‘water bodies’ in each initial temperature (280K, 290K, 300K).
By comparing grass and water bodies, we can find out in which the urban heat island effect is much larger.
3. Graph
(1) timeseries
We can recognize the temperature changes at each case as time goes by, and the temperature gradient which is derived from finite difference scheme. Also, we can derive minimum and maximum values to compare the deviation according to initial temperature and land use type.
(2) cross-section plots
We can find the maximum wind speed of each case. Also, we can analyze how urban heat island effect changes in relation of the initial temperature and land use type.
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