Geology 1350 Lecture 9 Outline of Last Lecture I. Formation of DewII. Types of FogIII. BigFamily of cloudsOutline of Current Lecture I. Stability II. ParcelIII. Cloud developmentCurrent LectureAir parcel-hypothetically balloon like bubble of air, some sort of density, temp and moisture are the same, ambient pressure decreases as goes up and expands and volume increases and vice versaAtmospheric environment- atmosphere around air parcel, air parcel doesn’t affect environmentStability(influences vertical motion) and movement- when in stable position it will return to its position if moved (stable position its is comfortable position) this is due to gravity; occurs in atmosphere as well, if air parcels are moved they will move back Return-stable; accelerate-unstable, stay-neutralForced motion-forcing air up over a hill over colder air Buoyant motion- when air parcel is warmer (less dense) than the environment, they riseThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Lapse rate- refers to the change of temperature due to altitude, decrease temp with height; two kinds environmental (vertical), and parcel (temp it has when displaced vertically); as well as dry and moist lapse rateNorth is 360 degrees as well as 0 degreesdry adiabatic-9.8kwet adiabatic- water in parcel , lowest temp cold at 9.5 (higher adiabatic lapse rate less humidity) close to 9.8, highest temp warmer at 3.0 (cools down slower than the environment unstable)(less adiabatic lapse rate, depends on the amount of humidity), the warmer the more water it can hold, the colder the dryeryou always have to think about 30 degrees cthe atmosphere is absolutely stable when the environmental lapse rate is less than the moist adiabatic lapse ratewhat conditions makes atmosphere stable?Warming aloft and cooling belowAir aloft may be warmed by warm air advection and subsidence warmingAir near surface may be cooled by cold air advection, and radiational coolingUnstable is the reverse- air parcel will be warmer than environment regardless of dry or moistand continue to riseUnstable is environmental lapse rate exceeds the dry adiabatic rates, vertical mixing can eliminate it, short-lived, results from surface heating What conditions makes atmosphere unstable?Air aloft may be cooled by cold air advection, and cloud radiational coolingAir near surface may be warmed by solar heating, warm air advection, and air moving over a warm surface ,What time of the day is the atmosphere unstable? Middle of the day 630, and month is juneStable? Morning, DecemberConditionally unstable atmosphere- morning stable, air parcel rises and enter dew point temp(condensation), then dry moves over wet adiabatic lapse rate , air becomes warmer and lighter and risesCloud development-active-unstable air, air cools to saturation, enhances buoyancypassive- in stable air , saturation through radiative cooling, forced lifting, and large scale liftinglike