: Focused on temperature and humidity change
Mixing Ratio Change
Relative Humidity
As the mixing ratio increases, the moisture content in the air rises, resulting in higher overall relative humidity. The difference in relative humidity between urban and rural areas also becomes more pronounced, with rural areas showing very high relative humidity, close to saturation.
Temperature
During the day, the temperature difference between urban and rural areas remains relatively small, but after midnight, the temperature gap widens significantly. As the mixing ratio increases, the temperature difference between urban and rural areas becomes more distinct, clearly highlighting the urban heat island effect.
Horizontal Wind Vectors
The lower the mixing ratio, the more distinct the horizontal wind flow between urban and rural areas. Even with a small temperature difference between the two regions, a strong pressure gradient forms, providing the driving force for horizontal winds.
Temperature Change
Relative Humidity
When temperature rises, the saturation vapor content increases, leading to an overall lower relative humidity. Conversely, when the temperature decreases, relative humidity rises. Higher temperatures result in lower humidity, which allows for effective cooling through evaporation, enhancing the urban heat island effect.
Temperature
At lower temperatures, heat is not evenly distributed across the urban; instead, certain areas become warmer than others, and the temperature difference between urban and rural area is less puonounced.
Horizontal Wind Vectors
At low temperatures, overall humidiy is higher, resulting in a varied temperature distribution and more complex wind patterns that differ from the default flow. At higher temperatures, the temperature difference between urban and rural areas rapidly decreases in the morning, causing weaker winds to converge toward the city.