Overview of Chapter 1-4: October 17

Chapter 1 Overview Dx dy = [R*cos  * d ][Rd  ]  Application to Atmospheric flow, e.g., Exercise 1.20

O 3 dissociation N 2, O 2 dissociation P=mg P ~ p o exp(-z/H) Rad. + conv. Main gases + greenhouse gases (Table 1.1)

SP NP Think: right-hand-rule. explains Flow around a low in NH Cyclonic: low pressure in both hemispheres, CCW In NH

Horizontal heating gradients: aquaplanet simulation

January July Surface winds + SLP, NCEP July rainfall Understand (simply) what are the Major meteorological regimes And why they are there.

Chapter 2: The Earth System Thermohaline circulation Cryosphere budget (table 2.1) Carbon Cycle Oxygen Earth History:hothouse period, glacial cycles Exercises: know how to do all of them, will provide numbers for calc.

Thermohaline Driver: Equator, Cooling and Freezing at High Latitude

Mass units of 10 3 kg m -2 ; equivalent to meters of water averaged over surface of earth

CO 2 + H 2 OCH 2 O +O 2 3 Carbon Cycles: The Quickest is

Euphotic zone takes up carbon dioxide, decaying matter Sinks it deeper. 2nd Carbon Cycle: The Ocean

Carbon in the Oceans: 1.CO 2 + H 2 O -> H 2 CO 3 carbonic acid. Equilibrate w/atmos. 2.H 2 CO 3 -> H + + HCO 3 bicarbonate ion 3. HCO 3 -> H + + CO 3 2- Net: CO 2 + CO H 2 O -> 2HCO 3 This is connected to Calcium from the Earth’s mantle: Ca + 2HCO 3 -> CaCO 3 + H 2 CO 3 coral. 3rd carbon cycle Where the Ca derived from the weathering of Rocks containing Ca-Si.

Oxygen: Unique component of Earth’s atmosphere Increasing with time: Photosynthesis creates oxygen - and - Reduction of water (H 2 O -> H 2 + O) via mineralization, with hydrogen escaping to space.

Early Earth’s History, in brief: 1.~ 4.5 billion years ago (bya): accretion from planetesimals, evidence is lack of noble gases relative to cosmos. 2. 1st ~750 millions years, named Hadean Epoch: more bombardment, early atmosphere, moon 3. 1st production of O 2, bya. Low atmos. conc., but ozone layer 4. Increased O 2, 2 bya. -> 1st glaciation

Sun’s luminosity increases w/ time as core contracts. Why wasn’t Earth’s surface frozen ?

Initial high methane conc. gives way to oxygen -> 3 major glaciations. First is ~ 2.3 bya

2nd glaciation: ~ 2.5 million years ago. Reduced plate tectonics -> reduced volcanic emission of CO 2. + Increased sink of CO 2 in oceans through increased Atmospheric carbon Movement of Antarctica to SP -> increased albedo Drake Passage opens, Panama Isthmus closes -> Changing thermohaline circulation -> less poleward heat transport ->colder Arctic

3rd glaciation mechanism: orbital mechanics primarily northern hemisphere summertime solar insolation changes that matter

Last glacial maximum 20,000 years ago Global sea level ~ 125 m lower CO 2 levels ~ 180 ppm Snow/ice extent preceeds CO2 changes

Venus Mars Jupiter Hot: No oceans: No hydrogen or water Atmosphere all carbon “runaway greenhouse Effect” Cold & small: No (liquid) water No vulcanism No atmosphere WHY LIFE ON EARTH ? ROLE OF OCEANS: ROLE OF CHEMICAL PHYSICS: ROLE OF TECTONICS ROLE OF OTHER PLANETS:

Chapter 3: Thermodynamics Of the W&H questions: ex. 3: , , , understand Ideas behind 3.53,3.54,3.55. Nothing on Carnot Cycle. Will probably include a sounding plotted On a skewT-lnp diagram & ask some questions about it. Know: gas law p=  RT. Applies separately to dry air, vapor Connecting to observed p,  where p = p dry air + p water vapor ; same For  =  dry air +  water vapor ) p =  R d T v where T v ~ T(1+0.61w) ; w=m vapor /m dry air Know: hydrostatic eqn., geopotential height and thickness; scale height

1st law of thermo: dq -dw = du dw=p* dV Specific heats c v = dq/dT| V constant = du/dT c p = c v + R Enthalpy = c p T ; dry static energy =h+  Stays constant if dq=0 Adiabatic; diabatic Know the “dry” and “moist” variables, What is conserved when,  e, w,q,e,w sat,e sat T d, LCL,latent heating

Understand what happens to these variables as An air parcel moves over a mountain (3.5.7) Static stability (  z > 0 condition) ; Concept behind brunt-vaisala f oscillations; Conditional instability; convective instability (  e  z > 0 condition); Entropy dS=dQ rev /T => s=c p ln  Adiabatic transformations are isentropic Concept behind Clasius-Clapeyron eqn.

Chapter 4: Radiative Transfer Exercises: ,4.51,4.55,4.56 Know the various units Integrated over all wavelengths: E=  T 4 ;  x W m -2 K -4 ; E is called irradiance, flux density. W/m^2

Sun Earth visible

Sahara Mediterranean

Energy absorbed from Sun establishes Earth’s mean T F sun = 1368 W m earth Energy in=energy out F sun *pi*R 2 earth = 4*pi*R 2 earth *(1.-albedo)*(sigma*T 4 earth ) global albedo ~ 0.3 => T earth = 255 K This + Wien’s law explains why earth’s radiation is in the infrared

High solar transmissivity + low IR transmissivity = Greenhouse effect Consider multiple isothermal layers, each in radiative equilibrium. Each layer, opaque in the infrared, emits IR both up and down, while solar is only down Top of atmosphere: F in = F out incoming solar flux = outgoing IR flux At surface, incoming solar flux + downwelling IR = outgoing IR => Outgoing IR at surface, with absorbing atmosphere > outgoing IR with no atmosphere 1. 2.

Manabe&Strickler, 1964: Note ozone, surface T

Whether/how solar radiation scatters when it impacts gases,aerosols,clouds,the ocean surface depends on 1. ratio of scatterer size to wavelength: Size parameter x = 2*pi*scatterer radius/wavelength X large X small Sunlight on a flat ocean Sunlight on raindrops IR scattering off of air, aerosol Microwave scattering off of clouds Microwave (cm) Scattering neglected

Rayleigh scattering: solar scattering off of gases proportional to (1/   aerosol Cloud drops R=10 -4  m R=1  m R=0.1  m Solar scattering Gas (air) Mie scattering: 1 < x < 50

Clouds. As a first approximation, infrared emissivity and Cloud albedo can be parameterized as a function of Liquid water path. Note dependence on LWP (and optical depth) becomes unimportant for thick clouds A further improvement is drop size

Radiation transmits through an atmospheric layer According to: I = intensity r= air density r = absorbing gas amount k =mass extinction coeff.  rk = volume extinction coeff. Inverse length unit Extinction=scattering+absorption Path length ds

Radiative heating rate profiles: Manabe & Strickler, or- Cooling to space approximation: Ignore all intervening layers Rodgers & Walshaw, 1966, QJRMS