Atmosphere Gaseous envelope surrounding the Earth.
Hydrosphere All liquid and solid water on the Earth. Oceans Lakes Rivers Groundwater…and Polar and high altitude ice caps. Approximately 70% of the Earth’s surface is covered with water. Only 3% of that water is fresh water.
Biosphere All forms of life Single celled protozoans to plant life to people.
Interactions Among The Spheres
The Spheres of Earth! Put these in order of increasing density: Asthenosphere Hydrosphere Lithosphere Geosphere
What is the best map of the earth’s surface? A globe Best model of earth’s shape= ping pong ball!
Latitude and Longitude
How do we communicate an exact location on earth’s surface to another person? What information do you need to locate a point on the earth’s surface? You need a coordinate system!
Coordinate System A system or group of defined imaginary lines forming a grid used for the determination or location of a point on the surface of an object. Two intersecting lines are needed to locate a point on a 2d surface. latitude/longitude system used to determine exact locations on the surface of the Earth
Latitude and Longitude How can positions on a sphere be located?
Latitude Angular distance north or south of the equator, measured from the center of the earth [the core]. They are Horizontal Lines running east-west, but, measure north-south. Measured in degrees, minutes, and second.
Latitude Like climbing a ladder, N is up the ladder S is down The equator is 0 degrees and the poles are at 90 degrees.
rungs of a ladder
Latitude lines are parallel to each other and are therefore also called parallels
Lines get shorter in length as you move away from the equator
if you drive east or west along a line of latitude, the altitude of Polaris remains the same
Recall the Altitude of Polaris equals the latitude of the observer
Longitude Angular distance east or west of the prime meridian, measured from the center of the earth [the core]. Vertical Lines running north-south through the poles, but, measure east-west. 180° east or west or the prime meridian is the largest longitude there is The prime meridian is 0 degrees and the International Date Line is 180 degrees.
the long way
Lines of Longitude (Meridian)
lines are not parallel
lines meet at the poles
Also called meridians
Lines are all of equal length
As you travel N & S along a Meridian your time stays the same
Each degree is divided into 60 equal parts called minutes.
Each minute of a degree is divided into 60 equal parts called seconds.
Equator An imaginary horizontal line circling the Earth halfway between the north and south poles. It is a referenceline for latitude. 0° latitude
Prime Meridian Imaginary vertical line from the N pole to S pole that passes through Greenwich England Reference line for longitude 0° Longitude on the Earth.
Other Reference Points North Pole – The point at 90°North of the equator. Very top of earth South Pole – The point 90°South of the equator. Very bottom of earth
International Date Line 180° East or West of the Prime Meridian On the direct opposite side of the earth from the prime meridian. The Prime Meridian and the International Date form a vertical circle that cuts the earth in ½ vertically
East of the International Date Line is a day earlier with the same time. West of the International Date Line is a day later with the same time
Time Zones The Earth rotates from west to east at a rate of 15°/hour. Time zones are divided up by 1hour/15° Travel to the west and the time gets earlier and travel to the east and the time gets later.
Time Zones + New Day - New Day Noon AM PM 10 2 4 6 8 2 4 6 8 10 0o 30o 60o 90o 180o 150o 120o 30o 60o 90o 180o 150o 120o (GMT) East West
If it is 3:00 PM for a person located on the tip of India, what time is it for people in the following locations? New York:______________ Alaska:________ Florida: _________________ Italy:___________________ California: ________________ 5 AM 12 AM 5 AM 11 AM 2 AM
Earths Fields and Field Maps What is a field? What is a field map?
Describing Earth’s Fields Field – a region which contains measurable quantities at every location. (i.e. elevation, temperature, pressure…) Field Value – the value of what is being measured. (i.e. temperature, elevation, pollution concentrations…) Magnitude – Value for a point on a field.
Field Values (cont.) Scalar Field – A field described in terms of magnitude alone (i.e. temp., pressure, humidity) Vector Field – A field described with both magnitude and direction (i.e. wind velocity, gravity, magnetic fields)
Isolines A line on a field map that connects all points of equal value. Note: ES0304
Types of Isolines Contour Line – Isoline that connects points of equal elevations on a contour map. Isotherm - Isoline that connects points of equal temperature on a field map. Isobar – Isoline that connects points of equal pressure on a field map.
Isosurface A surface in a field that has the same field valuethroughout.
Important Field Map Terms Topographic map/Contour map – A map that uses contour lines to show elevation and landforms. Elevation– Height above mean(average) sea level. Contour interval – Vertical distance, or change in elevation, between adjacent or consecutive contour lines.
Scale The ratio of a model to the object. (i.e. globe to earth) Use the scale on the map as the ruler to measure that map.
Angle of Declinationor Magnetic Declination The angle between true north (geographic north, north pole) and magnetic north. The angle of declination variesdepending on your position on the earth.
General Contour Map Rules Rule of ‘V’s – as contour lines cross a stream they bend uphill. The steeper the slope the closer the lines are to each other.
CONTOUR LINES BEND WHEN CROSS STREAMS UPSIDE DOWN V’S POINT UPSTREAM STREAMS FLOW DOWN
CLOSER CONTOUR LINES = STEEPER GRADIENT TOPOGRAPHIC MAPS WOULD BE VERY CLUTTERED IF ALL CONTOUR LINES WERE LABELED, SO ONLY HEAVIER LINES called an index contour SHOW LABELS
Rules for Drawing Isolines: 1. Isolines connect points of equal value. 5 5 10 10 10 10 15 15
2. Isolines are gentle, curving lines- no sharp corners. 5 5 10 10 10 10 15 15
3. Isolines are always closed curves even though the map might only show part of it.
4. Isolines NEVER cross- this would mean that one point has two different values. Ex: one spot has two temperatures? 60 ° 50 ° 40 ° 30 ° X 20° Z Y
5. Isolines usually are parallel. (They have a parallel trend.)
Visualizations of contour lines http://geology.asu.edu/~sreynolds/topo_gallery/topo_gallery.htm
Tips on Drawing Contour Lines
Always draw a contour line so that elevation reading is higher on one side of the contour line and lower on the other side.
Assume a steady elevation change between neighboring readings when positioning contour lines.
Adjacent contour lines tend to look alike.
Continue drawing a contour line until it reaches the boundary of plotted data or “closes” to form a loop by making its way to its starting point.
Contour lines never stop or end within a data field, and they never fork, touch or cross one another.
Contour lines cannot skip values and must always appear in sequence.
Only draw contour lines that fall within the range of data reported on the map.
100m 90m 10km = 9m/km 10m 100m – 10m 10km = = 10km Gradient –a measure of how a field value changes with distance. Gradient = Change in field value Distance
Gradient Gradient shows how quickly the value changes from one point to another.
A steep (high)gradient changes quickly and the isolines are close together. A gentle (low)gradient changes slowly and the lines are far apart. Steep area Gentle area 1km=1cm
Calculate the gradient of the slope along the line drawn in the diagram. Assume that elevations are given in feet. Show work including formula below: Steep area Gentle area 1km=1cm
Making Contours worksheets Worksheets can be printed from: http://www.rcmurphy.net/Medina%202005/documents/Contours123.doc
What is the pattern of the contour lines around a simple hill? Concentric circles getting smaller - hill
Identify the features marked at A and B
Hachure contour lines (lines with tick marks) show depressions – the first hachure is equal to the last contour line passed 20 20 10
WHAT DOES THIS PROFILE SHOW? VOLCANO NOTICE HACHURE DEPRESSION LINES IN CENTER SHOWING VOLCANIC VENT
Profiles Profile – a side view of an area showing elevation.
TOPOGRAPHIC PROFILES TOPOGRAPHIC MAPS SHOW THE ELEVATION OR VERTICAL DISTANCE ABOVE SEA LEVEL OF THE SURFACE OF THE EARTH TOPOGRAPHIC PROFILE IS A SIDE VIEW OF AN AREA CUT ALONG A PARTICULAR LINE.
Notice line AB on the next page
So, if we were to look at a profile view of line AB on our topographic map, what might we expect to see? Predictions? Time to FIND OUT! Step 2
Take out a piece of scrap paper
Make a small tick at A and B
Make a small tick where each contour line crosses AB
Label each tick mark with the correct value!
Make the X-axis exactly as long as line AB.
Next, decide what the HIGHEST and LOWEST elevation values are that line AB crosses on your topographic map and create a scale. You may wish to increase your scale by the contour interval on the map to make things easier. In this case, we are going up by 10’s, because our contour interval on the map is 10 meters.
Remember Labels and Units!
Hold your scrap paper page up to the profile.
Transfer the tick marks directly onto the profile.
straight edge may help
connect the dots!
This is what you might expect the “profile” or cross section view of line AB to look like! Notice how the line dips below 250m where it crosses Long Creek
Does it make sense? SURE! There is a creek flowing through this region. Think about where it would flow on your profile. We also recognize the V shaped contour lines that indicate the direction of water flow.
The contour lines point up the page (orange), but Long Creek flows down the page.
Contour lines point upstream. Stream flows from high elevation to low elevation. So a stream flows in the opposite direction the contours point.
Or… if you are lucky enough to be able to do your profile on the same page as the topographic map… You can use the: “Drop down a dotted line” method! Example
Same idea, but no need for tick marks and scrap paper!