GEOG 1114 1st Edition Lecture 14Outline of Last Lecture -Review before Exam 1 -Test strategies Outline of Current Lecture -Atmospheric Disturbances-Air masses and Fronts: definitions/ characteristics -Types of Air Masses -Types of Fronts Current Lecture Air Masses and FrontsAir Mass- Distinct parcel of air builds up- temp- moistureFront- Boundary between two different air masses General Characteristics:Involve variable, distinct air parcels or air massesMove through mid-latitudes and low-latitude zonesIn the form of spiralingCyclones:Low pressure at the surface- air coming in and rising- clockwise These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Anticyclones:High pressure descends and spirals outward In Mid-LatitudesTypes of Air Masses:Source RegionsPolar P cold (capitals refer to temp. characteristics)Tropical T warmContinental c dry (lower case refers to moisture characteristics)Maritime m moistArctic A very coldEquatorial E very warmGeneral Classes of Air masses:A - Arctic air mass- typically builds at the polesmP - Maritime Polar- air masses towards the poles that develop over the ocean-wet and coldcP - Continental Polar- dry and cold cT - Continental tropical- Dry south west- New Mexico areamT - Maritime Tropical- moist, wet, warm E - Equatorial FRONTS: The boundary or interface between two unlike air masses.Four TypesWarm Front:When war air moves into an area of cooler air the forward edge of the arm air is called a warm front. When it comes into contact with the colder air the warm air pushes up over the cold air. Convergent, frontal uplift brings condensation and precipitation.Usually move slowly an bring steady rainsCold Front:When cold air moves into an area occupied by warm air the forward edge of the cold air is a called a cold front. The cold air pushes under the warm air forcing the warm air t rise. The frontal slop is much steeper as there is rapid development of cumulonimbus clouds with precipitation occurring just ahead of the front.This cause a great drop in temperature and a line of strong, short storms in spring and summer*What causes thunderstorms to develop? An extremely cold front meets a warm front and pushes it up rather quickly. The frontal activity produces energy from the latent heat + instability + uplift (adiabatic cooling) Stationary Front- same energy butting up against each other The boundaries between two air masses that are not moving displace each other.PPTN and weather are not predictable along such fronts.Often associated with gently rising warm air, which can produce, limited pptn.Occluded Front Formed when a cold front overtakes a warm
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