AOSS 401, Fall 2006 Lecture 19 October 26, 2007 Richard B. Rood (Room 2525, SRB) 734-647-3530 Derek Posselt (Room 2517D, SRB)

Slides:



Advertisements
Similar presentations
The General Circulation of the Atmosphere
Advertisements

Unit 9: Circulation Patterns of the Atmosphere
Recitation Geostrophic Balance Thermal Wind Effect of Friction.
Q-G vorticity equation Q-G thermodynamic equation We now have two equations in two unknowns,  and  We will solve these to find an equation for , the.
UPPER AIR DYNAMICS (continued) MSC 243 Lecture #8, 10/22/09.
Air Pressure and Wind Pressure: the amount of force exerted per unit of surface area Pressure can be increased in 2 ways 1.By increasing density or decreasing.
Midlatitude Cyclones Equator-to-pole temperature gradient tilts pressure surfaces and produces westerly jets in midlatitudes Waves in the jet induce divergence.
Ch 7 – Scales of Atmospheric Circulations
The General Circulation of the Atmosphere
General Circulation and Kinetic Energy
MET 61 1 MET 61 Introduction to Meteorology MET 61 Introduction to Meteorology - Lecture 12 Midlatitude Cyclones Dr. Eugene Cordero San Jose State University.
What Makes the Wind Blow? ATS 351 Lecture 8 October 26, 2009.
General Circulation and Climate Zones Martin Visbeck DEES, Lamont-Doherty Earth Observatory
Atmospheric Circulation
AOSS 321, Winter 2009 Earth Systems Dynamics Lecture 12 2/17/2009
Class #13 Monday, September 27, 2010 Class #13: Monday, September 27 Chapter 7 Global Winds 1.
General Circulation & Thermal Wind
What Causes the Wind Worksheet.
Things to look for on the weather maps Visible and IR satellite images (& radar too): Look at cloud movements and locations - do they correlate with what.
AOSS 401, Fall 2006 Lecture 8 September 24, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
ATS/ESS 452: Synoptic Meteorology Friday 09/26/2014 Continue Review Material Geopotential Thickness Thermal Wind.
General Circulation of the Atmosphere Lisa Goddard 19 September 2006.
AOSS 401, Fall 2007 Lecture 24 November 07, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
The simplest theoretical basis for understanding the location of significant vertical motions in an Eulerian framework is QUASI-GEOSTROPHIC THEORY QG Theory:
AOSS 401, Fall 2007 Lecture 27 November 28, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
ADVENTURE IN SYNOPTIC DYNAMICS HISTORY
AOSS 401, Fall 2007 Lecture 25 November 09, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
Thickness and Thermal Wind /aos101/wk12.html /aos101/wk12.html.
AOSS 401, Fall 2007 Lecture 15 October 17, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
METR March Review Hydrostatic balance Ideal gas law p = ρ R d T v, ρ = p / R d T v Take layer average virtual temperature, R and g as constants.
AOSS 401, Fall 2007 Lecture 6 September 19, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
AOSS 401, Fall 2006 Lecture 9 September 26, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
AOSS 401, Fall 2007 Lecture 12 October 3, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
ATS/ESS 452: Synoptic Meteorology
AOSS 401, Fall 2007 Lecture 23 November 05, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
Synoptic Scale Balance Equations Using scale analysis (to identify the dominant ‘forces at work’) and manipulating the equations of motion we can arrive.
How Does Air Move Around the Globe?
The Wind: PGF Pressure gradient force is what sets air in motion
AOSS 401, Fall 2006 Lecture 17 October 22, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
MET 10 1 The General Circulation of the Atmosphere.
AOSS 401, Fall 2007 Lecture 21 October 31, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
AOSS 401, Fall 2007 Lecture 11 October 1, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
Lecture 11 Picking up pieces from previous lectures + – result of surface force balance – scales of motion – mesoscale systems: sea breeze, land breeze.
AOSS 401, Fall 2006 Lecture 18 October 24, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
Lecture 9 Conceptual model of the global circulation –Conservation of angular momentum Subtropical jetstream –ITCZ –Hadley circulation Upper-air midlatitude.
ATS/ESS 452: Synoptic Meteorology Friday 08 January 2016 Review Material Overview of Maps Equations of Motion Advection Continuity.
AOSS 401, Fall 2006 Lecture 16 October 19, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
Mid-Latitude Cyclones
Potential vorticity and the invertibility principle (pp ) To a first approximation, the atmospheric structure may be regarded as a superposition.
Atmospheric Dynamics Suzanne Gray (University of Reading) With thanks to Alan Gadian and Geraint Vaughan. Basic dynamical concepts.
Class #17 Monday, February 16, Class #17: Monday, February 16 Surface pressure and winds Vertical motions Jet streams aloft.
ATS/ESS 452: Synoptic Meteorology Wednesday 09/10/2014 Quiz! (Short?) Weather Discussion Continue Review Material Geostrophic Wind Continuity Vorticity.
Weather Basics Air Pressure and Winds. Air Pressure Air has a mass and exerts a force called atmospheric pressure Air pressure is measured in millibars.
Global Wind Belts & the Jet Stream
AOSS 401, Fall 2006 Lecture 7 September 21, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)
PRESSURE & WIND, GENERAL CIRCULATION, JET STREAMS.
SO254 - Advection.
Synoptic Scale Balance Equations
Global and Local Winds.
Planetary (Rossby) Waves
ATS/ESS 452: Synoptic Meteorology
Cause of vertical motions
Global and Local Winds.
Richard B. Rood (Room 2525, SRB)
Richard B. Rood (Room 2525, SRB)
Richard B. Rood (Room 2525, SRB)
Richard B. Rood (Room 2525, SRB)
Richard B. Rood (Room 2525, SRB)
Richard B. Rood (Room 2525, SRB)
Richard B. Rood (Room 2525, SRB)
Presentation transcript:

AOSS 401, Fall 2006 Lecture 19 October 26, 2007 Richard B. Rood (Room 2525, SRB) Derek Posselt (Room 2517D, SRB)

Class News October 26, 2007 Homework –Homework 5 posted today –Includes a programming assignment that will be posted this afternoon/evening –Focus your attention on question 1

Today Bring together physical concepts and preview the rest of the course Material from Chapter 6 –Middle Latitude Structure –Quasi-geostrophic theory

Flow over a mountain range West to East

What is happening with planetary vorticity? (In the (east-west, north-south) plane) Depth, H Depth, H + ΔH west east s n Depth, H - ΔH Depth, H + ΔH f is greater for deflections to north f is less for deflections to south f + ζ is less than earth’s vorticity and wants to turn north. Arrives here wanting vorticity. “Overshoots”

Flow over a mountain range East to West

What is happening with planetary vorticity? (In the (east-west, north-south) plane) Depth, H Depth, H + ΔH west east s n Depth, H - ΔH Depth, H + ΔH Flow from east planetary and relative vorticity interact together, no overshoot or undershoot.

Wind and geopotential 200 hPa Note: Troughs associated with mountain ranges, continents

Observations of the Atmosphere Vorticity –Small scale flow –Large-scale flow Large scale flow and the climate system –Heat transport –Jet streams –Development of mid-latitude cyclones

Vorticity on Small Scales From the southern California fires: What is the cause?

Vorticity on Large Scales Remember, vorticity is caused by –Wind shear –Rotation in the flow Can we identify these on weather maps? (The following maps come from

300 mb Wind Speed

Where is there positive vorticity?

500 mb Vorticity

Thermal Wind Remember, thermal wind relates –Vertical shear of geostrophic wind –Horizontal temperature gradients Can we identify these on weather maps?

Where are the strongest ?

850 mb Temperature

Convergence/Divergence Remember, vertical motion on large scales directly related to –Convergence/divergence of ageostrophic wind –Curvature in the flow Can we identify these on weather maps?

Where are surface lows/highs?

Surface Precipitation

850 mb Temperature

Concepts Vorticity: shear and curvature –Why is curvature vorticity (as opposed to shear vorticity) usually associated with developing low pressure systems? Divergence and convergence and location of surface high and low pressure systems Thermal wind—vertical shear of the horizontal wind and horizontal temperature gradients

Concepts Features commonly found together –Jet stream –Upper level positive vorticity –Fronts –Midlatitude cyclones (low pressure systems) Coincidence? More on this later…

Large scale flow and the climate system

Transfer of heat north and south is an important element of the climate at the Earth’s surface. Redistribution by atmosphere, ocean, etc. SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE CLOUD heat is moved to poles cool air moved towards equator This is a transfer. Both ocean and atmosphere are important! Large scale weather systems transport large quantities of thermal energy from equator toward the poles

Hurricanes and heat

Mid-latitude cyclones

Mid-latitude cyclones & Heat

Mid-latitude Cyclones & Jet Stream

An estimate of the January mean temperature north winter south summer tropopause stratopause mesosphere stratosphere troposphere note where the horizontal temperature gradients are large

An estimate of the January mean zonal wind north winter south summer note the jet streams

An estimate of the July mean zonal wind north summer south winter note the jet streams

Wind and geopotential 200 hPa Note: Variability in east-west of the wind field. Note: Troughs associated with mountain ranges, continents Note: Time variability of the wind field.

Waves in the atmosphere 300 mb Jet Stream Animation

Short summary We have strong mean zonal winds. We have latitudinal and time variability of the zonal winds –Quasi-stationary long waves. On these quasi-stationary long waves, mid-latitude cyclones form and propagate.

Mid-latitude cyclones What we know: –Low pressure systems –Form through spinup of low-level positive vorticity –Divergence/convergence is key This is just the beginning… –Always closely associated with fronts—why? –Sometimes develop rapidly, sometimes not at all—why?

The mid-latitude cyclone

Mid-latitude cyclones: Norwegian Cyclone Model

Fronts and Precipitation CloudSat Radar Norwegian Cyclone Model

Relationship between upper troposphere and surface note tilt with height

Idealized vertical cross section

What’s at work here?

Mid-latitude cyclone development

Mid-latitude cyclones: Norwegian Cyclone Model ptic/cyclone.htmhttp:// ptic/cyclone.htm

Cold and warm advection cold warm

Lifting and sinking

Increasing the pressure gradient force

Relationship between upper troposphere and surface divergence over low enhances surface low // increases vorticity

Relationship between upper troposphere and surface vertical stretching // increases vorticity

Modern education at its best. /tools/swf/ /tools/swf/

Analysis Tools We have used many of the concepts and tools that we have introduced and explored. –Observed characteristics of the atmosphere –Conservation principles –Scale analysis: Geostrophic and hydrostatic –Thermal wind –Divergence and convergence These ideas are integrated into quasi- geostrophic theory (analysis and prediction)

Programming Exercise Gain experience writing programs to –Read data –Analyze data –Plot data Tools for research/analysis

Remember the vertical structure of the atmosphere Hydrostatic Eq. of State

If we assume T is constant with height (Isothermal)

If we assume T varies with height (Realistic)

If we assume T varies linearly with height (Not a bad assumption, in general)

Programming Exercise Read in data from two sounding files –Height –Potential temperature Compute pressure on each level –Isothermal atmosphere –Varying temperature –Constant lapse rate Use this information –Geostrophic wind –Temperature gradients

Programming Exercise Goals: programming concepts –Reading data –Arrays –Loops –Iteration Materials posted to ctools this afternoon/evening –Skeleton MatLAB program –Data –Instructions

Next Week Programming exercise in class Monday Start looking at quasi-geostrophic system –Scale analysis of equations in pressure coordinates –Quantify wave movement and development