1 Lecture 1/15 Ice ages occur every 250,000,000 years This ice age began 40,000,000 years ago Natural greenhouse enhancement causes the earth to be about 30 degrees C ~ 50 degrees Fahrenheit warmer that it would originally be The earth right now is only 4 degrees Fahrenheit above the coldest the earth will ever get. Over the span of 1 billion years, the average earth temperature will change about 15 degrees Farenheit.
Lecture 2 1/17 Climatology - Climate: The processes of exchange of energy & mass between the earth (surface and ocean) and the atmosphere over a long period of time. - Climate relates to sum of all of the following: - Temperature (T) - Precipitation (P) - E (not sure what it means) - Cloud cover - RH (Relative Humidity) - Winds - Temperature and Precipitation are the two most important climate factors - 30 year averages are used - Monthly distributions are important as well - Weather: Day to day state of the atmosphere. Short changes in T, P, air, RH, etc. Climatology: A Brief History - Clim comes from the Greek word Klim = slope/inclination. It is the relation of the angle of the sun relative to the horizon to climate - Near equator: Sun is the directly overhead - Mid-latitudes: Alititude from 26.5 in the winter to 73.5 in the summer. - Arctic: Sun always near the horizon "Airs, waters and places" First climatology book, written by Hippocrates in ~400 B.C. "Meteorologia" by Aristotle 334 B.C. - First meteorology Treatise - Not much done until the 1500s - Galileo: Thermometer (1593) - Torricelli: Barometer (1613) Low Pressure System: The winds rotate in a counter-clockwise motion; brings storms, noreasters occur High Pressure System: The winds rotate in a clockwise motion; clear, sunny skies Climate: Broad composite of average conditions of a region, measured in terms of temperature. (Avg T, avg Tmax, avg Tmin, avg Tmedian), amount of rainfall or snowfall, snow and ice cover, winds, relative humidity, clouds, etc. Climate applies to longer term changes (years and longer) rather than short term fluctuations.
-
Lecture 3 Notes 1/22/08 Resolution: The amount of detail secured/retrieved from climate data in particular time resolution - Last 500 years months - Last 500 years 5-10 years
-
- back to 500,000 years 10,000 years - back to millions of years ~million years Hypothesis: New idea to explain a phenomenon. Informal ideas that have not been widely tested by the larger community of scientists doing similar research Theory: When a hypothesis is capable of explaining a large number of observations. Theories tested by models and additional observations. Models: Math. Representations of systems/computer models of the earths climate system (1D, 2D, 3D, etc.). Climate Forcing: - Cause of a change in the climate - Increased solar radiation - Increase in atmospheric dust from volcanoes - Increase in C02 (Greenhouse Effect) - The effect or result of climate forcing is called response.
Response: From the term "forcing," refers to those factors that drive or cause change; "responses" are the effects the climatic changes that occur. - Changes that occur: Force Response Increase in solar radiation Rise in T Increase in atmospheric dust Scattered solar radiation; decrease in T CO2 Warmer air Climate Forcing: Causes of Changes in Climate - Tectonic Processes: Mountains, continuous drift, Volcanoes - Changes in the strength of the solar sun: -11/yr sun spot - Insolation Longer cydler
Lecture 4 Notes 1/29/08 Lecture 5 Notes 1/31/08 Formation of earths atmosphere 1) Proto Earth forms in solar nebula by accretion of gas, dust and planetismals. Proto Earths atmosphere was extensive and composed of Hydrogen (75%), Helium (23%) and Heavy Elements (2%) rich in molecules such as methane (CH4), Amona (NH3), H2O...much like Jupiter now. 2) Diffusion: Heavy elements sink toward the center. Lighter gasses rise. Light gases in atm burned off and blown away by sun. Bombardment by debris (coments/planetismals) continues. Melting of solid earth starts (4.5 4.3 Billion Years ago) 3) Earth loses almost its entire original (primitive) atmosphere. Solid earth differentiates Iron, Nickel, Core, Mantle, thin crust (4.4 4 Billion years ago) 4) Secondary atmosphere produced by intense outgasing from volcanoes/collisions. Becomes like venus today~100x more dense than today. CO2 (90%), N2(5%) A(1%), H20, S, CH4 (4%). Large Greenhouse Effect 5) Earth cools down. Oceans form H2O (gas) H2O (liquid) (3.8 3.5 Giga Years ago) 6) Life starts in oceans...photosynthesis (algae plankton...6H2O +6CO2 6O2+ C6H12O6)...CO2 decreases and O2 is given off (3.7-3.5 Giga Years) 7) Present atmosphere, N2 (78%), O2 (21%), Argon A (.8%), CO2 (.038%) *1 atmospheric unit (AU) = 93x106 miles. Mercury is .39 AU, Venus is .7 AU, Earth is 1 AU, and Mars is 1.5 AU. These are all the terrestrial planets. Then comes the asteroid belt which is 2.8 AU *The asteroid belt was actually a planet trying to form but the gravitational pull of Jupiter prevented that
Climate forcing factors: Tectonic mountains, volcanoes, continental drift Solar Sun changes in strength longer Insolation cycles Earth Orbital Changes Anthropogenic forces CH4, CO2, O3; human causes; man made Correlation between CO2 and Temperature CO2 from air bubbles trapped in polar ice, as CO2 rises, Thermometer: expansion of mercury with temperature forces it up in the column of glass, liquid moves faster and heats up and expands Types: expansion Electric resistance: porcelain, coil resistance, voltmeter, battery Bourdon: expands/contracts with T Insect thermometer: insects are quiet above 100, bees are idle as well Crickets chirp, locusts sing above 85 Ants stay home below 55, Katydids mute Bees sluggish below 52 All insects must below 40 All insects dormant below 32
*counting the number of cricket chirps in 14sec and add to 40, you can get the temp in oF Temperature: Kinetic Energy KE = mv2 = 3/2 kT, where k = constant Temp: a mesure of kinetic energy Temperature Scales: Fahrenheit: 212, 32, -480 (boiling, freezing, absolute zero) Celsius: 100, 0, -273 Kelvin: 373, 273, 0 Tc = 5/9(TF 32) TF = 9/5Tc + 32 Tk = 273.15 + Tc Tc = Tk 273 100oF = average body temperature of cows Pressure Gradient difference in Patm btwn. two locations: P1 P2, causes wind to blow Pressure Gradient forces: Fp = 1 / (Density Air) * (P1 P2) Force acting on air to equalize the pressure gradient Force acts from high to low pressure (diffusion) 2/7/08 - Equator is a low pressure system because air is moving away, with wind systems - Inter Tropical Convergence Zone air from equators meet each other - Subsiding, falling air, very dry, hence the ring of deserts around the world - Rising air, clouds and rain occurs
- Pressure gradient force causes air to rise (L press), which cools (H press), producing clouds, which converge and condense, forming drops of liquid Coriolis Effect deflection of winds to the right in N.H. but to the left in S.H. due to rotation Polar front Rossby wave
First couple slides are in the notebook because they are diagrams E Earths magnetic field blocks the plasma ejected from the sun and forces it around the earth, but does nothing to block the light from the sun. In the 1600s, there were very few sunspots located on the surface (maximum of nine per decade, dropping down to zero being detected in one particular decade). However, now in the 2000s, there are 100-200 detected sunspots. The lack of sunspots in the 1600s is thought to have contributed to the earths climate changing.
Proxies of Solar Activity: Aurorae Owens Dictionary states that "...the aurora borealis is a very common phenomenon in countries near the pole; but there are not many upon record, as having appeared in England before that of March 1715. Since that time however, they have been and still continue very frequent." Impact of Sun on Climate Major Climate Factors - Insolation Flux received from sun (Most Important) - Albedo Volcanoes (dust, aerosols), ice/snow and clouds - Greenhouse Gasses H2O, CH4, & Co2
1/ 4
279 1 1 A L T (K )
Where: A = Albeda L = Luminosity R = Distance in AU TGGH = Greenhouse
Lsun
R
1/ 2
TGH
For earth, r= AU, A = .3,
TGH = 31K T~286K ~ 55F
Recent studies have shown that a diminished period of solar activity between the ~1300s and ~1850s lead to a "Little Ice Age" The hes no agreed upon beginning date to the Little Ice Age. There are a series of events, each one of which could be considered as the "loose" beginning date. - 1250 for when Atlantic pack ice began to grown southward, and glaciers began to grown in Greenland - 1300 for when warm summer stopped being consistently dependable in Northern Europe Lecture 9 Notes 2/14/08 Sun fast facts Diameter of sun: 860,000 miles (earth is 1/100th of the size, Jupiter is 1/10th) Mass of the sun: 2x1033 (need 330,000 earths to match this) Temperature of the Photosphere (outermost layer of the sun) 580 K~10,000F Lifetime of the sun: 9x109 years
Luminosity = Energy/s L (sun) = surface area x (E/cm2 L (sun) = 4R(earth x T4 (T4 is Stefans Law) L (sun) = 3.86 x 1030 erg/s (equivalent to setting off every nuclear bomb on earth every second) L (young sun(4 billion years ago)) ~ .7 L(present day sun) T (young sun) ~560K R (young sun) ~ .9R(todays sun In 4.5 billion years, the sun will expand into a red giant and will be extend out to mars C-14: Carbon 14 Isotope of ,,normal Carbon Half life of carbon 15 is about 5730 years
12 -6C
has 6 neutrons and 6 protons
Test Review Alaskan winds are easterly, we are southwesterly, Puerto rico is southeasterly Corealis effect No summer Summer of 1816 due to the volcano in 1815 (Tamboro India, biggest eruption in 2000 years, Mt. St. Helens was 1/100 equivalent)
2/14/08 Sun most important climate factor - e = mc2 Core has nuclear fusion 41H1 2He4 + e + neutrinos Diameter of sun = 860,000 miles Mass of sun = 330,000 earths of 2x1023 gms? Visible surface of sun photosphere (what we see) Lifetime 9x109 years Luminosity = Surface of Sun * Energy in 1 cm2 at surface = 4*pi*r2 * (sigma*T4) = 3.86x1030 ergs/s (every h-bomb on earth at once, every second) Velocity of rotation 2 km/s Rotation Period 25 days Temperature 5000 10,000 oF