Figure 3.9
Saturation vapor pressure varies with air temperature. The blue line shows how much water vapor must be in the air at a given temperature for saturation to occur. As the temperature increases, more water vapor must be added for saturation to occur. For example, at 10°C, the saturation vapor pressure is about 12 mb (point A), and at 20°C, the saturation vapor pressure is 24 mb (point B).