What are the factors that affect air pressure?
1)temp.-cold air is more dense than warm air
2)Humidity-DRY AIR VS. WET AIR
3)Elevation or Altitude-As height above sea level increases air pressure decreases
High Pressure
-clockwise
-high-dry conditions
-known as anticyclones
-air sinks(pushes down on surface of earth)
-air moves away from center of earth(divergent winds)
Low Pressure
-counterclockwise
-low-lousy weather
-known as cyclone
-air rises away from surface of earth
-converging air
Humidity
-measure of the amount of water vapor in the air
How does Water Vapor get into the Air?
-Evapo Transpiration
Factors that Affect the Amount of Evaporation that takes place
1)Temp.-higher temps. faster rate if evaporation
2)how much water vapor is already present in the atmosphere
-If air is saturated there is less potential for more water to evaporate.
3)Surface Area-bigger body of water, the more evaporation
Ways to Get Air Saturated
1)have more evaporation occur
2)cool down air
-Dew Point-temp. at which condensation occurs
-can never be higher than air temp.
*-the closer the dew point and temp. of the air are to each other the higher the humidity
Clouds
-collections of tiny water droplets or ice crystals suspended in the atmosphere
How Do Clouds Form?
-air rises
-air cools
-reaches dew point
-condensation occurs
Condensation Nuclei
-this surface is called condensation nuclei
-condensation cannot occur without a surface to condense on
What Causes Air to Rise?
-heating(convection currents)
-fronts
-air moving over a mountain(orographic lifting)
500 Rule
When taking air pressure off a station model if the # is more than 500 place a 9 in front and a decimal before last number. If the #is less than 500 place a 10 in front of the # and a decimal before the last #.
Which weather variable can be determined by using a psychrometer?
relative humidity
An observer measured the air temp. and the dew point and found the difference between them to be 12 degrees celsius. One hour later, the difference between air temp. and the dew point was found to be 4 degrees celsius. Which statement best describes the c
The relative humidity was increasing and the chance of precipitation was increasing.
A parcel of air has a dry-bulb temp. of 16 degrees celsius and a wet-bulb temp. of 10 degrees celsius. What are the dew point and relative humidity of the air
4 degrees celsius dew point and 45% relative humidity
A temp. of 73 degrees Fahrenheit is approximately equal to a temp. of
23 degrees celsius
The relative humidity is 100% when
the air is at its saturated vapor pressure
What is a pressure gradient?
-how much air pressure changes over a certain distance
What is the field value when calculating pressure gradient?
air pressure
What is wind?
-movement of air along the surface of earth
What causes wind?
1)unequal heating of earth's surface
2)differences in air pressure
According to the Earth Science Reference Tables what has the highest specific heat?
Liquid Water
What effect does a high specific heat have on the rate of heating or cooling of an object?
it takes a longer time
Winds blow from ____ pressure to ____ pressure.
high to low
Air Pressure/ Isobars
Isobars always go up by four millibars.
On which side of the low pressure center will the wind speed be the greatest?
west
Which two stars have the most similar luminosity and temperature?
Alpha Centauri and the Sun
Which star color indicates the hottest star surface temperature?
blue
Compared to the temperature and luminosity of the star Polaris the star Sirius is
hotter and less luminous
In nuclear fusion what occurs?
Lighter elements are converted to heavier elements.
Which star is cooler and many times brighter than Earth's Sun?
Betelgeuse
Which planet's orbit around the Sun is most nearly circular?
Venus
How do Jupiter's density and period of rotation compare to Earth's?
Jupiter is less dense and has a shorter period of rotation.
Which planet is approximately 20 times farther from the Sun than Earth is?
Uranus
Which planet would float if it could be placed in water?
Saturn
Terrestrial planets move more rapidly in their orbits than the Jovian planets because terrestrial planets are
closer to the Sun
The same side of the Moon always faces Earth because the
Moon rotates once as it completes one revolution around Earth
Which of the following planets has the lowest average density?
Mars
Compared to Mars, Mercury moves more rapidly in its orbit because Mercury
is closer to the Sun
Which statement correctly compares the size, composition, and density of Neptune to Earth?
Neptune is larger, more gaseous, and less dense.
Latitude and Longitude
-measured in degrees
-represents angular distances calculated from the center of the earth
What is latitude?
-all lines of latitude are parallel to the Equator
-latitude values indicate the angular distances between the equator and points north or south of it on the surface of the earth
What is Longitude?
-lines of longitude are called meridians
-lines run perpendicular to lines of latitude and they pass through both poles
Equator
-line which encircles the earth at an equal distance from the North and South Poles
Geographic coordinates
-coordinate values given as latitude and longitude
Great Circle
-A circle formed on the surface of a sphere by a plane that passes through the center of the sphere. The Equator, each meridian, and each other full circumference of the Earth forms a great circle. The arc of a great circle shows the shortest distance bet
Meridian
-An imaginary arc on the Earth's surface from the North Pole to the South Pole that associates all locations running along it with a given longitude. The position of a point on the meridian is given by its intersecting latitude. Each meridian is perpendic
Parallel
-a circle or approximation of a circle on the surface of the earth, parallel to the Earth and connecting points of equal latitude
Prime Meridian
The meridian of longitude 0 degrees, used as the origin for the measurement of longitude. The meridian of Greenwich, England, is the internationally accepted prime meridian in most cases.
Which is more elliptical the orbit of the asteroid or Neptune?
asteroid
The diagram represents the Earth's orbital path around the Sun. The Earth takes the same amount of time to move from A to B as from C t D. Which values are equal within the system?
The shaded sections of the diagram are equal in area.