Urban heat effect
: focusing on relative humidity
MOTIVATION
The Importance of Research on UHI and Water-vapor
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Based on prior research, it has been observed that the intensity of urban heat tends to diminish with precipitation (Kim Yu-jin and Choi Young-eun, 2012). Precipitation leads to a reduction in the heat energy absorbed by the urban surface due to a decrease in solar radiation energy. Consequently, this results in a decrease in the temperature differential between the urban area and its surrounding regions, weakening of the UHI (Lee and Baik, 2010).
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However, when the atmosphere experiences a significant water vapor feedback, heat waves become concurrent with elevated humidity levels, resulting in a magnification of heat, thereby intensifying the Urban Heat Island effect, particularly in moist regions (Feinberg, 2022).
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Building upon prior research that has demonstrated the correlation between high water vapor content and increased Urban Heat Island intensity, it is noteworthy that the presence of precipitation has an attenuating effect on the urban heat island phenomenon. Therefore, the goal of this study is to compare and analyze the intensity of urban heat island phenomena according to the different values of humidity.
Our Expected Result
When compared to ideal conditions, an increase in atmospheric water vapor leads to the amplification of the urban heat island(UHI) intensity due to water vapor feedback. On the other hand, a decrease in water vapor results in a weakening of the UHI effect. For the UHI index, a key variable characterizing the UHI phenomenon, increasing water vapor content corresponds to a more significant UHI effect, and in the comparison of U-W wind vectors, higher water vapor content leads to faster wind speeds. Conversely, if water vapor content decreases, both variables will decrease proportionally.
Furthermore, as water vapor increases, the temperature rise in urban areas will be more rapid, and in contrast, a decrease in water vapor will result in a relatively smaller increase in urban temperatures compared to wetter conditions.