Correction to SyllabusMy Office Hours:

W2-3 & Th2-3 - Ellison 6844

If you’re interested in an honors section, meet here after class to talk about

when/where/what.

Honors Section

Natural disaster shaved millionths of a second off planet's day

The Earth has been rocked on its axis. The devastating earthquake that struck the Indian Ocean on 26 December was so powerful that it has accelerated the Earth's rotation, geophysicists have declared. They estimate that the shockwave shortened the period of our planet's rotation by some three microseconds.

The change was caused by a shift of mass towards the planet's centre, as the Indian Ocean's heavy tectonic plate lurched underneath Indonesia's one, say researchers at NASA's Jet Propulsion Laboratory in Pasadena, California. This caused the globe to rotate faster, in the same way that a spinning figure-skater accelerates by tucking in her arms.

news.nature.com

Schoolgirl saved family and others by recognizing signs of coming tsunamiLONDON (AP) - A British schoolgirl who recognized the signs of a coming tsunami thanks to a recent geography lesson saved her family and some 100 other tourists at a Thai beach. Tilly Smith, 10, realized they were in danger when she saw the tide suddenly rush out -an indication earthquake-driven tidal waves are only minutes away -and told her mother, The Sun said in its Saturday edition. She explained that she had studied tsunamis only two weeks before at her school in Oxshott, just south of London. Her parents, Penny and Colin Smith, warned nearby vacationers and staff at their hotel in Phuket, and the hotel swiftly evacuated Maikhao beach, minutes before the devastating waves struck, the newspaper said. The Sun reported that the beach was one of only a few in Phuket where no one was killed or seriously hurt.

may save your life!!!

So, this course

Last time - Chapter 1

•latitude, longitude•remote sensing•GIS

Prime meridian and time zones

Map projections

Chapter 1: continued

Time Zones First, the Earth revolves 360 degrees in

one day or 15 degrees for each hour

Each time zone (an hour of time!!) would span 15 degrees of longitude, with 7.5 degrees on either side of a central meridian - giving 24

time zones in total for the planet

Then, local clock time could track local solar time fairly well

Global Time Zones

and the time zones and meridians in the US

15o long

Greenwich Mean Time (GMT) was world time standard (now called Coordinated Universal

Time or UTC)What is the time in California if the UTC is 5pm?Given this time difference, roughly how many

degrees of longitude separate CA and the prime meridian (PM)?Given our latitude at UCSB, how many kilometers

separate us from the PM? deg-lon(lat) =

cos(lat)*deg-latcos(34.5) = 0.824deg-lat = 111 kmdeg-lon(34.5) =

0.824*111 km = 91.5 km distance ~ (91.5 km/deg)* (8

zones)*(15 deg/zone) = 10980 km

(this is not a great circle)

Time Travel and the IDLthe International Date Line (IDL) roughly

follows the 180-degree meridian and officially marks the beginning of each day

Scale

Projection

Characteristics of Maps

Map Scalescale - the ratio of the area represented on a map to the real area

the fraction gives the scale - the larger the second number (the denominator), the

smaller the scale size

Map Projections

the act of reducing a globe to a flat, 2-D surface is called

map projection

a globe is the only faithful representation of the spherical

Earth

during this process, distortion always occurs, and the

degree of distortion depends on the scale of the projection

the classic distortion is area

Mercator Projection

http://www.public.asu.edu/~aarios/resourcebank/maps/page10.html

Area of Greenland = 0.8 million square milesArea of Africa = 11.6 million square miles

Four (of many) map projections

the standard line

represents the area

where the least

distortion occurs

Robinson Projectionthis is the projection you will see most often

in the text - it represents a compromise between equal areal and true shape

you will be exposed to these concepts and learn for yourself how projections work in Lab 1, “Getting a

Grip on the Globe”

you will also learn about why great circles form the shortest connection

between two points on a globe

Chapter 2: Solar energy to earth and the seasons

Earth’s orbit around the sunSolar energy: composition and

amount reaching Earth

Solar insolation and Earth’s radiation budget

The reasons for seasons

March of the seasons

Scientific Notation (see Appendix C in text)

useful for expressing very large or very small numbers Nx10b

where (1 <= N < 10) and b is the exponent to which 10 is raised (pos. or

neg.) Examples…

35,000,000 = 3.5 x 107

0.000049 = 4.9 x 10-5

First, some galactic geography…

100,000 light years across

light year - the distance light travels in a year

speed of light = 300,000 km/sec

Milky way is 9.5x1017 km across

our solar system is 11 light hours wide (12 billion km

across)

Earth’s Orbit Around the Sun-elliptical-

Credit: http://www.physics.uwo.ca/everyday-

physics/images/earth-orbit.gif

aphelionNH

summer

perihelionSH

summer

=> the southern hemisphere (SH) summer will be slightly more intense

than the NH summer

152 million km

147 million km

Credit: http://www.env.leeds.ac.uk/envi2150/lecture5/eccentricity.gif

The elliptical orbit varies on 100,000-year time scales

present-day

this is one of the variations that contributes to

glacial and interglacial periods

the sun-earth distance varies by 17 million km

over this cycle

Credit: http://www.harmsy.freeuk.com/images/fu

sion.gif

Solar activitythermonuclear fusion is occurring in the sun’s

interior, releasing tremendous amounts of energy

the difference in mass is converted to energy

which radiated as light

Credit: http://www.plasmas.org

isotopes of hydrogen

Courtesy of SOHO/[instrument] consortium. SOHO is a project of international cooperation between ESA and NASA.

captured by the extreme ultraviolet telescope

on the SOHO

satellite

The Sun

The sun radiates 3.9x1026 W (390 billion billion million watts) which reach the Earth

(after 8 minutes & 20 seconds)

Earth intercepts only one two-billionths of this output (thankfully)

This relatively small output powers [nearly all] climate & weather dynamics and life on Earth

At the top of the atmosphere (480 km up), the solar constant is 1370 W / m2

Electromagnetic Radiation

frequency is #

wavelengths per time

red light

green light

blue/violet light

electromagnetic spectrum

ROY G BIV

Freq

uenc

y in

crea

sing

Ener

gy i

ncre

asin

g

Wav

elen

gth

in

crea

sing

all objects radiate energy in

wavelengths related to their

surface temperatures (the higher the T, the

shorter the wavelength)

the sun’s surface temperature is

6000 degrees C; Earth’s is about 15 degrees C

90 degrees< 90 degrees

note the difference in area to equal the

total radiation received

subsolar point = the point on Earth’s surface where the sun is 90 degrees

overhead

Relative Intensity = sin(90-latitude)recall that sin(90)=1

sin(45) = 0.71 (or 71% of the intensity when the sun is directly overhead)

at the Arctic Circle (66.5 N)intensity = sin(90-66.5) = 0.4

note the difference in area to equal the

total radiation received

at the Arctic Circle (66.5 N)intensity = sin(90-66.5) = 0.4

1/0.4 = 2.5

Credit: http://langley.atmos.colostate

.edu/srb/toasw2dc.jpg

northern hemisphere

winter

northern hemisphere

summer

would you expect higher summertime values in one of the

hemispheres?

Seasonal insolation by latitude

Reasons for the Seasons

we will take this up on Friday…