1. Case Setting
We have set up 9 cases for analyzing the urban heat dome phenomenon. First of all, as controlled variables, the land type was set to urban and mixed forest in all nine cases. After that, in order to find out the difference in the heat dome phenomenon with respect to season and urban intensity, the initial conditions of temperature and urban size were modified.
1.1. Land Type Settings (Controlled Variable)
Land Use Index
1: Urban and Built-Up Land
15: Mixed Forest
The Korean Peninsula is characterized by mountainous terrain, which occupies more than 70% of the total area. Specifically, in South Korea, forests cover 42% of the country's land area. Of these forests, 37% are deciduous forests, 33% are coniferous forests, and 29% are mixed forests, which include both deciduous and coniferous trees. To reflect these unique characteristics of the Korean Peninsula, we have set the land type as 'Mixed Forest' for areas that are not classified as urban.
1.2. Urban Size Settings (Manipulated Variable)
To observe the varying patterns of urban heat island effects across different urban sizes, we have set the land size into three categories.
The entire grid is fixed at 100 grid points, and out of the total 200km, the sizes of the urban area are set to 40km, 80km, and 160km. For this, variables in the namelist.input file and module_initialize_ideal.F file were modified to e_we=100 and lm=10, 20, 40, respectively.
1.3. Initial Condition Settings (Manipulated Variable)
Default
Summer
Winter
We used three Initial Conditions; the default initial condition using the original Input_sounding, and modified initial conditions to simulate the summer and winter data using adjusted Input_sounding.
We adjusted the Surface Potential Temperature values in the Input_sounding data to reproduce the seasonal difference in the heat dome phenomenon. However, as we simulated the summer and winter solely through temperature changes, the model does not reflect seasonal variations of humidity .
The calculation method for Surface Potential Temperature:
① The atmospheric pressure is calculated from the given altitude.
② Using the calculated pressure and given potential temperature data, we calculated the temperature.
③ We simulated summer and winter by adding specific conditions to the calculated temperature values.
- Given the climate characteristics of Seoul, the average annual temperature is 12.8℃ (285.95K),
the coldest month is January with -1.9℃ (271.25K), and the hottest month is August with 26.1℃ (299.25K).
- These temperatures were converted into absolute temperatures, then proportionally adjusted to set the
temperatures for summer and winter.
④ Using the temperature of summer and winter, calculate the potential temperature of two seasons at each
altitude.
2023-2 Numerical Weather Prediction
Team 4
Ideal Urban Heat Island Simulation