AIR MASSES the air masses they are great portions of the atmosphere that present similar characteristics of temperature, humidity and pressure, determined for the region of origin of the air mass. According to Mendona (2007), the formation of an air mass requires three basic conditions: considerable surfaces with planura and extension, decreases altitude and homogeneity how much to the characteristics. Of this form, them they are formed on the continental oceans, seas and plains, and almost always they are originated in the places where the circulaes are slower and the more steady atmospheric conditions, as in the regions of the high subtropical and polar pressures. The more time the air mass to remain on the respective region of origin, denser it will go to become, therefore to if moving for another region it will have its modified characteristics. As consequence of the displacement, it occurs brusque changes in the conditions atmospheric-time, influencing the regions for where pass and modifying the temperature and humidity.
This movement of the masses occurs due to the alterations of its characteristics, what it represents the variation of the atmosphere in relation to the surface. Thus, Mendona (2007) affirms that: An air mass that possesss main characteristics of its area of formation, that not yet suffered expressive modification from its original conditions is called primary air mass, while that one that presents significant modification as resulted of the influence of the superficial conditions of the new areas for where it passes is called secondary air mass. (MENDONA, 2007, P. 100). In accordance with Blacksmith (2006), the humidity of an air mass depends on the origin region to be on a maritime or terrestrial surface. Thus, a maritime air mass originates on a great water surface, therefore, will be sufficiently humid and consequently it contains much cloudiness, giving origin to the precipitation. Already an air mass continental it is originated on the terrestrial surface and it is normally dries.
Tags: geography
