Presentation Slides for Chapter 1 of Fundamentals of Atmospheric Modeling 2 nd Edition Mark Z. Jacobson Department of Civil & Environmental Engineering Stanford University Stanford, CA March 10, 2005

Brief History of Meteorology 340 B.C. –Meteorologica - Aristotle 1400's –Hygrometer - Cryfts (1450) –Anemometer - Alberti (1450) 1500's –Thermoscope - Galileo 1600's –Barometer - Torricelli (1643) –Les Meteores - Descarte (1637) 1700's –Trade winds - Hadley (1730) 1800's –Three-cell model - Ferrel (1855) –Weather maps of surface pressure 1900's –Weather prediction from maps - Bjerknes (1903) –Polar front theory - Bjerknes (1921) –Numerical weather prediction - Richardson (1922) –First computer forecast - Charney / von Neumann (1948) –Daily balloon observations (1940's) –Weather satellites (Tiros I, 1960)

Excerpts from Aristotle’s Meteorologica There are two reasons for there being more winds from the northerly than the southerly regions. First, our inhabited region lies toward the north; second, far more rain and snow is pushed up into this region because the other lies beneath the sun and its course. These melt and are absorbed by the earth and when subsequently heated by the sun and the earth’s own heat cause a greater and more extensive exhalation. Let us now explain lightning and thunder, and then whirlwinds, firewinds and thunderbolts; for the cause of all of them must be assumed to be the same. As we have said, there are two kinds of exhalation, moist and dry; and their combination (air) contains both potentially. It condenses into cloud, as we have explained before, and the condensation of clouds is thicker toward their farther limit. Heat when radiated disperses into the upper region. But any of the dry exhalation that gets trapped when the air is in process of cooling is forcibly ejected as the clouds condense and in its course strikes the surrounding clouds, and the noise caused by the impact is what we call thunder.

Scales of Motion (Table 1.1) Molecular scale (<< 2 mm) Molecular diffusion Molecular viscosity Microscale (2 mm- 2 km) Eddies Small plumes Car exhaust Cumulus clouds Mesoscale ( km) Gravity waves Thunderstorms Tornados Local winds Urban air pollution Synoptic scale ,000 km) Pressure systems Weather fronts Tropical storms Hurricanes Antarctic ozone hole Planetary scale (>10,000 km) Global wind systems Rossby waves Stratospheric ozone loss Global warming

Atmospheric Model Gas processes –Emission –Photochemistry –Gas-to-particle conversion –Cloud removal Aerosol processes –Emission –Nucleation/condensation –Aerosol, cloud coagulation –Dissolution/chemistry/crystallization –Dry deposition/sedimentation –Rainout/washout Cloud processes –Activation on aerosol –Conden./evap./deposition/sublim. –Hom./het./contact/evap. freezing –Cloud, aerosol coagulation –Precipitation/lightning –Dissolution/chemistry Radiative transfer –UV/visible/near-IR/thermal-IR –Scattering/absorption GasAerosolHydrometeor –Snow, ice, water albedos Meteorological processes –VelocityGeopotential –PressureWater vapor –TemperatureDensity –Turbulence Surface processes –Temperatures and water content of SoilWaterSnow Sea iceVegetationRoads Roofs –Surface energy/moisture fluxes –Ocean-atmosphere exchange –Ocean dynamics, chemistry Fig. 1.1