How do air masses form? How do air masses get their distinctive characteristics?
• Air masses derive their temperature, moisture, stability characteristics according to the surface beneath them during formation • Air masses form by remaining stationary (non-moving) over a unform underlying surface • To form, warm air masses must remain over a surface for several days to assume underlying characteristics • Cold air masses may require a week or more to form because stable air does not mix easily • Air masses can be very different from one another by forming over very different surfaces • The Sahara Desert is very hot and very dry • The North Pacific Ocean is cool and moist Air Mass Characteristics and Code Notation ~ • Atmospheric scientists use a two-letter shorthand code to name air masses • One letter stands for air mass temperature, the other for moisture • The first letter stands for moisture; a small letter • m meaning Marine: moist • c meaning Continental: dry • The second letter is for temperature; a capital letter • Note that these are latitudinal (N-S) posi
