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.
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.
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.
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.
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.
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.
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.
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!