Lectures_6 - Lapse Rates The streaks of falling...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Fig. 5-23, p.128 Lapse Rates The streaks of falling precipitation that evaporate before reaching the ground are called virga.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lapse Rates Environmental “Dry” Adiabatic “Moist” adiabatic T change with height Adiabatic – no exchange of energy with outside Cooling – cloud formation – rain Stability w.r.t vertical T Z
Background image of page 2
Lapse Rates • Environmental Lapse Rate, Γ e Ambient or local rate of change Mean global rate 6.5°C/km (trop) Γ e < 0 Inversion, temperature increases with height Pollution events Arctic winter (gamma) e DT T DZ Z = = Γ - T Z
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Fig. 4-4, p.80 Air Parcel
Background image of page 4
Dry adiabatic Lapse rate, Γ D Q: how rapidly will air cool when moved vertically? – This is qualitatively different from Γ e It concerns movement of air parcels (AP) in the atmosphere Considered to keep their integrity for “short” periods Adiabatic – no energy exchange with surroundings As we move AP s around, the pressure between the AP and ambient atmosphere is very small otherwise shock waves are generated Lapse Rates
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Dry adiabatic Lapse rate, Γ D We start with introduction of specific heat of air at constant pressure, C p, Defn: Heat required to raise the temperature of 1 kg of air by 1°C at constant pressure – Can also define C v for constant volume C p = 1,005 J/kg/K C v = 700 J/kg/K Lapse Rates
Background image of page 6
Specific heats Substance J/kg/C Water (liquid) 4186 Wet mud 2512 Ice 2093 Sandy Clay 1381 Dry Air 1005 Sand 795 Granite 794
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Example : How long to heat, by10°C, a room 2.5 m x 4mx 10m using a 100 W light bulb (W = 1J/s) Need mass of air in room and so volume Volume = 10 2 m 3 mass of air = volume. ρ (air) = 10 2 m 3 x 1 kg/ m 3 10 2 kg 10°C rise at (at C v ) would require mass. T . C v = 10
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/05/2010 for the course EATS 1011 taught by Professor Johnm during the Winter '10 term at York University.

Page1 / 39

Lectures_6 - Lapse Rates The streaks of falling...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online