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Cloud Physics

Cloud Physics. What is a cloud?. Cloud Physics. What is a cloud? Water droplets or ice crystals in the air. Cloud Physics. What is a cloud? Water droplets or ice crystals in the air. Why important?. Cloud Physics. What is a cloud? Water droplets or ice crystals in the air.

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Cloud Physics

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  1. Cloud Physics • What is a cloud?

  2. Cloud Physics • What is a cloud? • Water droplets or ice crystals in the air.

  3. Cloud Physics • What is a cloud? • Water droplets or ice crystals in the air. • Why important?

  4. Cloud Physics • What is a cloud? • Water droplets or ice crystals in the air. • Why important? • Precipitation • Solar radiation

  5. Cloud Physics • What is a cloud? • Water droplets or ice crystals in the air. • Why important? • Precipitation • Solar radiation • What do we want to learn? • Formation of clouds • Development of precipitation

  6. Cloud Physics • What is a cloud? • Water droplets or ice crystals in the air. • Why important? • Precipitation • Solar radiation • What do we want to learn? • Formation of clouds • Development of precipitation • Methods?

  7. Cloud Physics • What is a cloud? • Water droplets or ice crystals in the air. • Why important? • Precipitation • Solar radiation • What do we want to learn? • Formation of clouds • Development of precipitation • Methods? • Cloud microphysics • Cloud dynamics

  8. Cloud Physics • Understanding the properties of clouds • What clouds are (why are they different) • How they develop in time • How they interact and affect the energy balance of the planet • Development of precipitation, rain, hail, and snow • Role in general circulation of the atmosphere

  9. Cloud Physics • Understanding the properties of clouds • What clouds are (why are they different) • How they develop in time • How they interact and affect the energy balance of the planet • Development of precipitation, rain, hail, and snow • Role in general circulation of the atmosphere • These subjects are important to • Radar meteorology • Weather modification • Severe storms research • Global energy balance (greenhouse effect)

  10. Overview • Thermodynamics of dry air • Water vapor and its thermodynamic effects • Parcel buoyancy and atmospheric stability • Mixing and convection • Observed properties of clouds • Formation of cloud droplets • Droplet growth by condensation • Initiation of rain • Formation and growth of ice crystals • Severe weather

  11. Atmospheric composition

  12. Atmospheric composition • Permanent gases • Variable gases • Aerosols

  13. Atmospheric composition • Permanent gases • Nitrogen, oxygen, argon, neon, helium, etc. • Variable gases • Water vapor, carbon dioxide, and ozone. • Aerosols • Smoke, dust, pollen, and condensed forms of water (hydrometeors).

  14. Review • Zeroth law of thermodynamics

  15. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law

  16. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ?

  17. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ? • Boyle’s Law

  18. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ? • Boyle’s Law • p  = RT = g(T) • Avogadro’s law (ideal gas)

  19. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ? • Boyle’s Law • p  = RT = g(T) • Avogadro’s law (ideal gas) • p  /T = R* / m =R (for individual gas or R’ for dry air) • m: molecular weight = ?

  20. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ? • Boyle’s Law • p  = RT = g(T) • Avogadro’s law (ideal gas) • p  /T = R* / m • m: molecular weight = ? • 1st law of thermodynamics

  21. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ? • Boyle’s Law • p  = RT = g(T) • Avogadro’s law (ideal gas) • p  /T = R* / m =R (for individual gas or R’ for dry air) • m: molecular weight = ? • 1st law of thermodynamics • dq = du + dw = du + p d = dh - dp • Work-heat relation (1 cal = ? J)

  22. Review • Zeroth law of thermodynamics • Concept of thermometer • Charles’ Law •  /T = R/p = f(p) • Define temperature, K = ? • Boyle’s Law • p  = RT = g(T) • Avogadro’s law (ideal gas) • p  /T = R* / m =R (gas constant for individual gas or R’ for dry air ) • m: molecular weight = ? • 1st law of thermodynamics • dq = du + dw = du + p d = dh - dp • Work-heat relation (1 cal = ? J) • Dalton’s law

  23. Review, cont. • Specific heats:

  24. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R

  25. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R • Equipartition of energy

  26. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R • Equipartition of energy • degree of freedom: f • u = fRT/2

  27. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R • Equipartition of energy • degree of freedom: f • u = fRT/2 • Entropy (3 meanings)

  28. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R • Equipartition of energy • degree of freedom: f • u = fRT/2 • Entropy • d = dq/T • Irreversible processes: entropy change is defined by that in reversible processes.

  29. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R • Equipartition of energy • degree of freedom: f • u = fRT/2 • Entropy • d = dq/T • Irreversible processes: entropy change is defined by that in reversible processes. • 2nd law of thermodynamics

  30. Review, cont. • Specific heats: c = dq/dT • cv =(q/T) • cp= ( q/T)p • cp = cv + R • Equipartition of energy • degree of freedom: f • u = fRT/2 • Entropy • d = dq/T • Irreversible processes: entropy change is defined by that in reversible processes. • 2nd law of thermodynamics • d system + d environment 0.

  31. Review: Processes Isochoric:

  32. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric:

  33. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric: pV0 = const, dq = cp dT Isothermal:

  34. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric: pV0 = const, dq = cp dT Isothermal: pV1 = const, du = 0, dq = -  dp = pd = dw Adiabatic:

  35. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric: pV0 = const, dq = cp dT Isothermal: pV1 = const, du = 0, dq = -  dp = pd = dw Adiabatic: pV = const, dq = 0 cp dT =  dp, cv dT =- pd where  = cp / cv = 1+2/f Polytropic:

  36. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric: pV0 = const, dq = cp dT Isothermal: pV1 = const, du = 0, dq = -  dp = pd = dw Adiabatic: pV = const, dq = 0 cp dT =  dp, cv dT =- pd where  = cp / cv = 1+2/f Polytropic: pVn = const. (adiabatic) Free expansion:

  37. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric: pV0 = const, dq = cp dT Isothermal: pV1 = const, du = 0, dq = -  dp = pd = dw Adiabatic: pV = const, dq = 0 cp dT =  dp, cv dT =- pd where  = cp / cv = 1+2/f Polytropic: pVn = const. (adiabatic) Free expansion: q= u= T = 0, 0

  38. Review: Processes Isochoric: dq = du, dq = cv dT Isobaric: pV0 = const, dq = cp dT Isothermal: pV1 = const, du = 0, dq = -  dp = pd = dw Adiabatic: pV = const, dq = 0 cp dT =  dp, cv dT =- pd where  = cp / cv = 1+2/f Polytropic: pVn = const. (adiabatic) Free expansion: q= u= T = 0, 0 Homework: 1.1, 1.2, and 1.3, 1.5* due on ?

  39. Diagrams P-V diagram:

  40. Diagrams • P-V diagram: work pd,

  41. Diagrams • P-V diagram: work pd, • u: state function, remains same in a cycle. • ∮dw=∮𝑑𝑞.

  42. Diagrams • P-V diagram: work pd, • u: state function, remains same in a cycle. • ∮dw=∮𝑑𝑞. • P-T diagram:

  43. Diagrams P-V diagram: work pd, u: state function, remains same in a cycle. ∮dw=∮𝑑𝑞. P-T diagram: Where is each state, triple point phase transitions.

  44. Diagrams P-V diagram: work pd, u: state function, remains same in a cycle. ∮dw=∮𝑑𝑞. P-T diagram: Where is each state, triple point phase transitions. e- diagram:

  45. Diagrams • P-V diagram: work pd, • u: state function, remains same in a cycle. • ∮dw=∮𝑑𝑞. • P-T diagram: • Where is each state, triple point • phase transitions. • e- diagram: • e: vapor pressure • phase transitions, isotherm.

  46. Diagrams • P-V diagram: work pd, • u: state function, remains same in a cycle. • ∮dw=∮𝑑𝑞. • P-T diagram: • Where is each state, triple point • phase transitions. • e- diagram: • e: vapor pressure • phase transitions, isotherm. • Stüve (p –T) diagram: adiabatic • T/ = (p/1000mb) , potential temp, =R/cp

  47. Diagrams • P-V diagram: work pd, • u: state function, remains same in a cycle. • ∮dw=∮𝑑𝑞. • P-T diagram: • Where is each state, triple point • phase transitions. • e- diagram: • e: vapor pressure • phase transitions, isotherm. • Stüve (p –T) diagram: adiabatic • T/ = (p/1000mb) , potential temp, =R/cp • Diagrams: area of a closed path

  48. Diagrams, cont. • Emagram: • Work: V is difficult to measure for a p-V diagram.

  49. Diagrams, cont. • Emagram: • Work: V is difficult to measure for a p-V diagram. • dw = pd = R’dT-  dp = R’dT – R’T dp/p • ∮ dw = -R’ ∮T d(lnp) • energy-per-unit-mass diagram (R’=R*/m)

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