航海海洋气象-（Marine Meteorology -）.docVIP

航海海洋气象3-12（Marine Meteorology 3-12） Section 1 air mass He Feng I. definition, formation and degeneration of air mass 1, air mass: in the same period of time in the horizontal direction of physical attributes (mainly temperature, humidity and atmospheric stability) larger distribution of large air. The horizontal range can range from several hundred to several thousand kilometers. 2, the formation of air mass conditions: a wide range of physical properties of the more homogeneous underlying surface. Suitable circulation (for a large area of air to stay on the lower surface for a long time and exchange heat and water vapor) 3. Denaturation: the gradual change of physical properties and weather characteristics during the migration of air masses. (denatured air mass: an altered mass of air) Air speed and depends on the differences between the old and new nature of the underlying surface size, the length of time, leaving the air source distance and air nature. Continental air masses change rapidly into the sea; marine air masses move slowly into land. Two. Classification of air masses and characteristics of air mass weather 1, geographical classification: according to the source of latitude and sea and land location: 1) ice air mass: formed in polar regions covered by perennial ice and snow, including ice, Continental, air mass, ice, ocean, air mass. Weather characteristics: dry and cold weather; low layer often has strong inversion layer, gas layer is very stable. 2) polar air mass: air masses formed in the middle and high latitudes, Polar continental air mass: dry, low temperature and sunny days in winter; In summer, the temperature and humidity in the lower air layer rise, the inversion layer disappears, the stability decreases, and the clouds are cloudy. Polar maritime air: winter, overcast or cloudy, sometimes appear precipitation, clouds, fog or rain and other weather stability. Summer, low temperature, damp, cloudy, cloudy day. 3) tropical air mass: air masses for