Air masses

The air mass - the amount of air in the troposphere, commensurate in size with the continents, oceans, or parts thereof, having certain physical properties (temperature, humidity, visibility, etc.), And move as a unit in the system atmofernyh currents. Depending on the stratification of the air masses are divided into stable and unstable.

Sustainable called air mass (usually warm), in which there are no conditions for the development of vertical air movements, t. E. Ascending currents develop in it very little or not at all developed. The stable air mass mostly formed inversion (temperature increase with height in the atmosphere instead of the usual descending order). The warm (stable) air mass in the summer there is overcast weather and satisfactory visibility, and in winter - the low stratus clouds, fog, drizzling rain and poor visibility.

Instability is called air mass (usually cold), which develops turbulence and convective motions

air, leading to the formation of cumulus clouds form. The cold (unstable) air mass in the summer, the formation of cumulus cloud forms, heavy rainfall, storm activity and the development of others, and in the winter falling snow flake and "cereals".

Flying in this air mass is accompanied by turbulence.

The horizontal dimensions of air masses are measured by thousands of kilometers and a vertical size can range from 1-2 km to the tropopause. The transition zone between adjacent air masses can be quite broad.

If such a transition zone of large horizontal temperature gradients, it is called a frontal zone.

Aeronautical meteorology