GEOG 1114 1st Edition Lecture 13 Outline of Last Lecture Dew Point and sensible heat Condensation Adiabatic Processes Precipitation Atmospheric lifting Outline of Current Lecture Review before Exam 1 Test strategies Current Lecture Test Strategies Remember to read every question Take your time Answer every question even when you are unsure Do your best Review for test Four Types of Atmospheric Lifting Convective Unequal heating of surface areas by conduction causes a parcel of air near the ground to be warmed more that the surrounding air Density of the heated air drops as air expands and it begins to rise convectively Uplift is more likely to happen if unstable air is involved Pressure of the unstable airdrops as it rises and it cools adiabatically to the dew point Condensation and clouds develop If temp humidity and stability conditions are just right the clouds will grow 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 into a cumulonimbus thunderhead and a downpour of showery rains or hail and lightning and thunder will result Orographic Air is forced to rise over a mountain barrier and it is cooled to the dew point Windward side side in which air is forced to rise Typically West Leeward side Side in which air descends Little PPTN Rain shadow Frontal Lifting When a cool and warm air mass meet a boundary or front is established between them The warm air mass is forced to rise above the adjacent cold front If the warm air is cooled to saturation precipitation can occur along the front Convergent When air converges there is a general uplift If lots of crowding occurs get more lift and instability and precipitation can occur Less common than others happens in ITCZ often associated with hurricane formation Place of the Earth in the solar system One of 8 planets 3rd from the sun The Sun a medium sized star that gets its energy from nuclear fusion is the central body source of energy The Solar System is part of the Milky Way galaxy which is just one of billions of galaxies in our universe The Universe originated from The Big Bang theory a cosmic explosion of matter and gases 13 7 million years ago Our Solar system originated between 4 5 and 5 billion years ago A Nebula is a huge cloud of gas that contracted inward from gravity to form the sun and the planets All planets revolve around the sun in an elliptical orbit counter clockwise to the sun There are 150 moons in our solar system We landed on the Earth s moon in 1969 Ours revolves around the earth once every 27 days What is a maps purpose They are used to convey information they help people understand spatial distributions and identifying patterns and teach one about size distance directions and understanding the layout of our planet Scale the mathematical relationship between objects shown on the map and the real world Expression of scale 1 Fractional Map scale Representative Fraction a k a RF expressed as a ratio or fraction Ex 1 24 000 1 24 000 It is dimensionless meaning you put the units in 2 Graphic Map Scale depicts scale with a bar graph 3 Verbal Map Scale Ex 1 inch is equal to 1 mile Large vs Small Scale Fractional Relationship Small Scale shows a large area with small detail Smaller Representative Fraction larger denominator Large Scale shows small area with large detail Large Representative Fraction smaller denominator We can make the following generalizations which help us understand surface pressure conditions Very warm surface conditions often produce low pressure at the surface a thermal low Warm low Strongly rising air often produces low pressure at the surface a dynamic low Very cold surface conditions often produce high pressure at the surface a thermal high Cold high Strongly descending air often produces high pressure at the surface a dynamic high Dew Point The temperature at which saturation occurs 100 humidity and condensation begins 1 The temperature at which saturation occurs 100 humidity and condensation begins 2 Varies with the moisture content of air 3 High Dew point indicate high moisture content in the air The Process Rainfall is a rare event because it requires three different things to for rain PPTN precipitation Water Droplet Formation Uplift Droplet Formation Condensation which produces tiny drops is not enough to produce precipitation Two mechanisms are thought to be responsible for droplet formation Ice Crystal Formation Raindrops form as ice crystals found in clouds with temp Below freezing grow by attracting water vapor to them They grow until they are heavy enough to fall Known as the Bergeron Process Collision Coalescence Raindrops form as small droplets collide and begin to merge and form larger droplets If large enough they begin to fall and as they do they continue to collide and merge causing larger drops to form that will eventually fall in the form of rain Merging only occurs if a positively charged droplet collides with a negatively charged one