2024 Volume 80 Issue 16 Article ID: 23-16007
Convective systems that form cloud streets during the winter season when the monsoon from the northwest prevails over Japan. They consist of cloud regions where water vapor condenses and clouds are formed in the updraft region of convection driven by the temperature difference between the warm ocean and the cold atmosphere, and non-cloud regions where no clouds exist in the downdraft region of convection. In this study, we extracted cloud streets that appeared near Ishikari Bay from November to March in 2015-2020, and showed that the difference in water vapor between cloud and non-cloud areas was on average 1.1 times greater in cloud areas with a standard deviation of 17%. Furthermore, we explained that the difference of both in water vapor is caused not only by the water vapor budget but also by changes in water vapor capacity due to thermodynamic effects, and proposed a method for estimating the contribution of water vapor condensation inside clouds and the effect of the uptake of surrounding air.
