Chapter 1.MOISTURE IN THE ATMOSPHERE
-Moisture content There is a limit to the amount of water vapor in the air at any given temperature. When this limit is reached saturation occurs and cooling will cause condensation and cloud will form.
-Dew pointYou can Asses the amount of water in the atmosphere from the dew point. The dew point is the temperature at a given pressure to witch air must be cooled to cause saturation.
-Nuclei must be present for condensation or sublimation to occur
-Relative humidity. compares the of water vapor in the air with the amount that it could hold if it were saturated and expressed as a percentage.
CHAPTER 2 ATMOSPHERE HOW IT IS HEATED
-The atmosphere is composed of the troposphere, stratosphere, mesosphere, and thermosphere.
-Stratosphere is heated by the ozone absorbing solar ultraviolet radiation.
-The troposphere is heated from the earths surface by absorption of terrestrial infrared radiation and by conduction.
-The troposphere is the highest over a warm troposphere and lowest over a cold troposphere.
-ReflectionSome of the solar energy that strikes the earths surface is reflected back out to space and does not heat the surface. The amount of reflection depends on the angle at which the radiation strikes the surface and on the type of surface it strikes.
-Convectionthe surface layer of the air heated by conduction becomes buoyant and rises up through the atmosphere as the convective current that carries surface heat upward into the atmosphere.
-Turbulent MixingWind causes turbulent air motion that mixes the surface layer of air that has been heated by conduction with the unheated air aloft, thus, spreading the heat upwards.
-Latent HeatWater Vapor evaporated into the atmosphere from the earths surface is frequently carried aloft. If this should condense, its latent heat is released.
-Advective WarmingAir being carried from a cold portion of the earths surface to a warmer portion by wind will have its lowest levels heated by conduction and the heat will be distributed upward by convection and Turbulent Mixing.
-CompressionThere are associations when large sections of the earths surface atmosphere subside. This would occur in the instance of air flowing down the side of a mountain range. As the air descends, it comes under increased atmospheric pressure and is compressed. This compression heats the subsiding air.
-Isotherms are lines drawn on a weather chart which join places of equal temperature.
CHAPTER 3 ATMOSPHERIC COOLING
-Radiation CoolingThe troposphere is heated from the earths surface by terrestrial radiation and conduction.
-Wind Effecton a windy night turbulence mixes the lower few thousand feet of the atmosphere and distributes the cooling effect throughout this layer.
-Cloud EffectA blanket of cloud, particularly at low levels absorbs terrestrial radiation and re-radiates some of it back to earth.
-Topographical Effectcold air is denser than warm air and at night it will flow into low line areas just as water flows downhill.
-Maritime Effectmuch more heat energy is required to rise the temperature of a body of water than that of dry soil and this heat is distributed through a considerable depth of the water compared to an inch or two of the soil.
-Adiabatic ProcessIf air, for some reason should be forced to rise, it will encounter lower pressure and expand. As it expands, its temperature will decrease.
Dry Adiabatic Lapse Rate3 C /1000
Saturated Adiabatic Lapse Rate1.5 C/1000
CHAPTER 4 STABILITY AND INSTABILITY
Steep Lapse Ratethe temperature decreases very rapidly with height. This implies unstable air.
Shallow Lapse Ratethe temperature decreases very little with height. This implies stable air.
Inversiontemperature increase with height; this indicates extremely stable air.
Isothermal Layerthe temperature does not change with height, this indicates very stable air.
Absolute Stability the environmental lapse rate is less than the saturation adiabatic lapse rate (SALR).
Absolute Instabilitythe environmental lapse rate is greater than the dry adiabatic lapse rate (DALR).
Conditional Instabilitythe environmental lapse rate is between the dry and the saturation adiabatic lapse rate. If the air is unsaturated, it is stable; if it is saturated, it is unstable.
Potential Instabilityinitially stable air becomes unstable as the whole airmass undergoes large scale ascent until it becomes saturated; this would occur principally with frontal lift and with convergence.
-Flight Characteristics of stable air.poor low level visibility, layer cloud continuous precipitation, steady winds, smooth flying.
-Flight characteristics of unstable air.Good visibility, Heap type cloud gusty winds turbulent flying
CHAPTER 5 ATMOSPHERIC PRESSURE AND AIR CIRCLUATION.
-Pressure at a given level is the force caused by weight of the air above the level they use aneroid or mercury barometers.
-Low pressure areas These are also called Depression or cyclones
-High pressure areas These are called anticyclones
-Troughs .These are elongated areas of low pressure
-Ridge.These are elongated areas of high pressure.
-Cols .Theses are neutral areas between two highs and two lows.
-Pressure gradient forceIf there is a pressure difference across the country air will begin to move from the region having high pressure directly towards the area with low pressure.
-Coriolis force ..As soon as the air begins t move it is influenced by another force called coriolis force right in the northern hemisphere and left in the southern hemisphere.
-Geostrophic wind a parcel of air at is under the influence of the pressure gradient force begins to move towards a lower pressure as it move the coriolis force deflects it to the right
-Latitude effectfrom 15 north to 15 south air does not flow parallel to the isobars but tend to flow more directly from high to a low.
-Curvature effectA geostrophic flow only the isobars are straight when they are curved the air moves in an arc or a circle and centrifugal force comes into play.
-Friction effect Topographical features on the earths cause friction that tends to retard air movement and reduce the wind speed in the low levels.
-CHAPTER 5 AIR MASSES AND FRONTS
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