)A warm air mass is advancing from the
south to the north across India on a day in
December. Which direction is the warm air
coming from, and what is the name of this
type of weather front?
Answers
Answer:
An air mass is a batch of air that has nearly the same temperature and humidity (Figure 16.14). An air mass is created above an area of land or water known as its source region. Air masses come to have a distinct temperature and humidity when they remain over a region for several days or longer. The heat and moisture leave the ground and move into the air above it, until the overlying air takes on the temperature and humidity characteristics of that particular region.
Air masses are created primarily in high pressure zones. They most commonly form in polar and tropical regions, which have very distinctive temperature and humidity. The temperate zones are ordinarily too unstable for air masses to form. Instead, air masses move across them, making the middle latitudes the site of very interesting weather.
Air masses can be 1,600 km (1,000 miles) or more across and several kilometers thick.
Temperature and humidity may change a bit horizontally across the air mass, but not too much. An air mass may have more changes with altitude.