tools: digital technology

Tools: Digital Technology

• Remote Sensing – Data collected from aerial photography and satellite imagery.

• GPS – Global Positioning System – System of satellites & receivers to plot location.

• GIS – Geographic Information System - System to manipulate & display spatial data.

Remote Sensing

• Aerial Photography

Remote Sensing

• Geostationary Satellites

– GOES (Weather)

• Global Positioning System– 24 satellites orbit earth every 12 hours– Time of signal to receiver gives distance– Triangulation gives location

• Geographic Information Systems– System for storing, analyzing and manipulating

spatially referenced data– Data consists of layers of one variable such as:

vegetation, landforms, or soils– Layers can be overlaid/combined for analysis or display– Applications include: resource management, planning,

hazard assessment, etc.

GEOG 1112: Weather and Climate

Earth-Sun GeometrySeasons

Our Place in Space

Speed of Light• 299,792 km/s (186,282 m/s)• Milky Way Galaxy – 100,000 ly across• Our Solar System – 11 ly across• Moon is 1.28 light seconds away• Gravity – mutual attracting force exerted by

the mass of an object on all other objects

The Sun

• About 4.6 Billion Years Old• Average Star, Nothing Special• 100 times diameter of Earth• Powers most natural processes on Earth• 8.3 min. for Sun’s energy to reach Earth• Strong Magnetic Fields/Sunspots

Solar Activity and Solar Wind• Solar wind = clouds of electrically charged

particles• Sunspots are caused by magnetic storms. These

cause changes in the solar output• Sunspots have activity cycles

Auroras

Earth-Sun Relationship• Most Physical Processes on Earth powered by

incoming radiation from Sun

• Earth-Sun Relationship Complex – Depends on:–Latitude–Position of Sun in Sky–Time of Year–Earth’s Rotation/Axial Tilt

Shape of the Earth• Insolation

• Variation in Sun Angle by Latitude

• Oblate Spheroid

• Subsolar Point

Atmospheric Beam Depletion

Solar radiation is diminished relative to the amount of atmosphere the radiation passes through.

High solar angles see little reduction in intensity as the path from the top of the atmosphere to the surface is short.

Earth’s Orbit Around the Sun

• Plane of the Ecliptic

• One Revolution = 365.24 Days

• Elliptical Orbit

• Perihelion/Aphelion

• Seasons not due to distance from Sun

Dimensions and Distances

• Earth’s orbit– Average distance from Earth to the Sun is

150,000,000 km (93,000,000 mi)– Perihelion – closest at January 3• 147,255,000 km (91,500,000 mi)

– Aphelion – farthest at July 4• 152,083,000 km (94,500,000 mi)

– Takes energy 8 min 20 sec to reach Earth– Plane of Earth’s orbit is the plane of the

ecliptic