EESC V2100 The Climate System spring 2004 Lecture 4: Laws of Atmospheric Motion and Weather
|
|
- Dinah Fox
- 5 years ago
- Views:
Transcription
1 EESC V2100 The Climate System spring 2004 Lecture 4: Laws of Atmospheric Motion and Weather Yochanan Kushnir Lamont Doherty Earth Observatory of Columbia University Palisades, NY 10964, USA
2 Horizontal Motion in the Atmosphere - Geostrophic Balance
3 Horizontal Motion in the Atmosphere The motion of air on Earth is described in terms of a 3-dimensional vector with a zonal (west-to-east) or x component, normally denoted u, a meridional (south-tonorth) or y component denoted v, and a vertical (upward) or z component w. In most cases, the motion is described relative to the rotating Earth. The more prominent component of atmospheric motion are in the horizontal (parallel to the surface of the Earth) dimension. In the vertical dimension, on scales larger than clouds and intense storms such as tornados, the motion is much smaller than in the horizontal and the atmosphere is close to being in hydrostatic balance. The equations governing horizontal motion are based on Newton s Second Law of Motion applied to a fluid system in a spherical reference coordinate system rotating with Earth. The main driving forces in the atmosphere are the pressure gradient produced either through thermal or dynamical effects, and gravity. Retarding or balancing the pressure gradient force is the Coriolis force an apparent force, which results from viewing the motion in reference to the rotating Earth. Close to the surface, friction is also an important force retarding force. Sometimes, when the motion is fast and circular, another apparent force, the centrifugal force comes into play.
4 The Pressure Gradient Force Just as we saw in the vertical dimension, the pressure gradient forces results from the difference in pressure acting over a distance as described in the following diagram: z - upward y - northward x - eastward p+δp Δz Δx Δy p direction of motion The pressure difference acting over a distance Δx create a force F x = -- ΔpΔyΔz (negative because eastward flow is produced by higher pressure to the west). The eastward acceleration (= force per unit mass) a x, (in m/s) exerted by the pressure gradient differece per unit mass is given by Newton s second law of motion: F x = -- ΔpΔyΔz = (ρδpδyδz)a, where ρ is the density of air. After canceling identical terms on both side of the equation we obtain: Similarly, in the y-direction: a a x = -- (1/ρ)(Δp/Δx). y = -- (1/ρ)(Δp/Δy).
5 Isobars The mapping of pressure on a horizontal surface, such as the sea level, is the first step in monitoring atmospheric motion Pressure data are collected simultaneously by a network of stations, converted to sea level and reported to weather centers four times daily, to create a synoptic representation of sea level pressure. The station data is interpolated to a regular grid and plotted as isobars - lines of equal pressure.
6 Pressure Gradients strong gradient weak gradient By viewing the patterns of the isobars, we can determine where the gradients are strong and where they are weak, thus assessing the strength of the horizontal pressure gradient and the direction of the pressure gradient force (PGF). Units of pressure: the MKS unit for pressure is 1 Pascal = 1 Newton/m 2 (the unit is named after the French scientist Blaise Pascal ). The standard sea level pressure in Pascal is and the order of magnitude of pressure variations is about 100 Pascals. A more workable unit of pressure is a millibar (or one thousands of a bar) which equals 100 Pascals (also called hecto-pascal).
7 Apparent Forces To study of body movement under force we use a frame of reference. A frame of reference is called inertial if it is at rest or if it moves with constant velocity (that is, constant speed and direction). If the reference frame is moving under acceleration it is non-inertial. Examples for non inertial frames of references are an accelerating car, a rotating platform (even if the angular velocity is constant), and our planet Earth. Non-inertial systems are under the influence of a force acting linearly or by exerting a torque on the system to cause rotation. To use such system as a frame of reference we need to introduce an apparent reaction force equal and opposite to the external one. Consider for example a train moving at a fixed direction and constant speed in the country side. If a passenger on that train decide to get out of her or his seat and move forrard, they will feel and react just as if they are walking in their own back yard. But if the trains decelerated suddenly the passenger would be jolted forward with the same acceleration as that of the braking train. That passenger may conclude that a force acted on her or him pushing them forward while in reality the train they were riding was pushed back. Non Inertial Frame of Reference and The train became a non-inertial frame of reference and in order to explain the effect on the walking passenger in that frame, we will have to introduce and apparent accelerating force equal to the force that slowed the entire train.
8 The Coriolis Force Next consider an observer, standing in the center of a merry-goround, shaped like a circle with a radius R and rotating in a counterclockwise direction (to the left) with an angular velocity Ω (as in the figure to the right) The observer sets a ball into motion towards the circumference of the circle, in the direction of the radius and with a speed v. Because the observer continues to rotate in the clockwise direction it will appear to him that the ball is turning to the right as it moves away. The faster the observer turns, the faster the ball curves to the right. The closer the ball gets to the circumference of the circle, the faster it will appear to move. To explain the balls behavior, the observer needs to introduce an apparent force which causes the apparent accelerated motion of the ball to the right with respect to the rotating merry-go-round. This force is known as the Coriolis force. d
9 The Coriolis Force (continued) To determine the magnitude of the Coriolis acceleration consider the following: after the ball reached a distance of R from the observer, we can identify an arc that forms between the point on the circumference of the circle at which the ball was originally aimed (straight ahead of the observer) and the point where it actually crossed the circle. The arc length, d is given by the time t elapsed from the beginning of the motion until the arrival at the circumference of the circle R times the speed at which the circumference is rotating (= angular velocity time the radius), namely: d = ΩRt Under acceleration the distance covered by a moving body is proportional to the square of time. Thus d is also equal: d = a c t 2 / 2 where a c is the acceleration - in this case, the Coriolis acceleration. Equating d from the two equations results in an expression for the Coriolis acceleration: a c = 2 ΩR / t Now, the time t is given by the ratio between the radius and the ball s speed: t = R / v Thus we obtain: a c = 2 Ωv The Coriolis acceleration (or force per unit mass) acting on a particle viewed in a rotating frame of reference is equal to twice the product of the angular velocity and the speed of the particle. The direction of the force and acceleration is perpendicular to the motion, acting in this case to the right when facing in the direction of the motion. R d Ω
10 R d Ω Ω Φ Ω Coriolis Force on Earth ΩsinΦ How does the situation on Earth resemble the rotating disk? The planet rotates around its axis (with the angular velocity vector pointing to the north (see bottom figure on the left). This is the direction of the vector at every point on the Earth s surface. At the North and South Poles Ω is vertical to the surface and anywhere else it is slanted to the surface with an angle equal to the local colatitude (90 minus the latitude angle, Φ). The local angular velocity component vertical to the surface is thus ΩsinΦ. It describes the rotation of the local surface around the radius connecting it to the center of the Earth with an angular velocity that decreases from the North Pole (Ω) to the equator (0) and then reversing sign in the Southern Hemisphere and continuing to decrease to the South Pole (-Ω). The Coriolis acceleration on Earth is thus a function of the latitude with: a c = 2(ΩsinΦ)v, On Earth: Ω = 2π /84600 = 7.27 x 10-5 rad/sec where v is the velocity of the the moving body with respect to the Earth. Based on this relationship we define the Coriolis factor f = 2(ΩsinΦ).The force is perpendicular to the body s motion acting to the right in the NH and to the left in the SH.
11 Coriolis Effect on Earth An aircraft heading out from the US West Coast (say San Francisco - latitude ~38 N), flying towards the East Coast (New York - latitude ~40 N) with an almost direct eastward heading, needs to continually correct its course to adjust for the Coriolis force otherwise it will find itself drifting southward to a lower latitude. Without correction, an aircraft flying at a speed of 900 km/hr (= 250 m/s) will drift south at an initial acceleration of: a c = 2Ωsin(38) 250 = x = m/s 2 This implies that for every hour of its flight the aircraft needs to correct its course by heading north a distance of: D = a c ( )/2 = m or about 90 miles.
12 Geostrophic Balance I: The primary horizontal balance of forces in atmospheric motion is the geostrophic balance. When an air parcel begins to move under a pressure gradient force (PGF), in a direction perpendicular to the isobars, and towards the low pressure, the Colriolis force (CF) begins to act, turning the parcel to the right (left in SH). Because CF depends of the particles velocity, this turning intensifies as the particle accelerates until the turning angle is 90 and CF is exactly equal to PGF and they both point perpendicularly to the motion, the pressure gradient force pointing towards the low pressure and the Coriolis force in the opposite direction.
13 Geostrophic Balance - Derivation To find how to express the geostrophic balance mathematically, examine the diagram on the right. The balance between CF and the PGF is expressed by the equal and 180 apart vectors P and C. In the NH the geostrophic wind blows in a perpendicular direction such that the low pressure is to its left (right in the SH). Note that the CF depends on the wind speed in the direction 90 to its left (right in the SH). The balance must also exist between the x and y components of the forces, separately, related the geostrophic wind components u and v). In the component balance, c x depends on v and c y on u, such that: c x = fv and c y = fu where f is the Coriolis factor. W PGF vector P = (p x,p y ) p x p y c y N S wind vector V = (u,v) v c x u E CF vector C = (c x,c y ) Northern Hemisphere (NH) force diagram Balancing these forces with the PGF results in the geostrophic balance: fv = (1/ρ)(Δp/Δx) fu = (1/ρ)(Δp/Δy) Note that the eqn in the x-direction provides a solution for v and that in the y- direction, for u:
14 Geostrophic Flow with Friction Friction slows down the wind, causing a weakening in the Coriolis force. A new balance is achieved between the resultant of the Coriolis force (CF) and friction on one hand and the pressure gradient force (PGF) on the other hand.
15 Friction, Convergence/Divergence, and Mass Continuity Friction leads to the convergence of air into the centers of low pressure and divergence out of the centers of high pressure. An important principle of any fluid motion, mass continuity (or mass balance) implies that there is rising motion in a low pressure system and sinking motion in a high, leading to a reversal of the convergence/divergence patterns aloft. The tendency of air to rise over a low pressure system creates favorable conditions for the formation of rain clouds. In high pressure systems the sinking motion leads to clear and dry conditions.
16 Mid-latitude Weather Systems
17 Synoptic Map This segment taken from a synoptic (weather) map of surface pressure shows isobars (contours of equal pressure in mb) and small flags, depicting the wind direction (the flags fly in the direction of the wind) and speed (each full flag bar is 10 knots and half a bar is 5 knots with 1 knot = 1/2 m/s). The flow is very close to geostrophic balance everywhere with a small tendency to flow across isobars towards the low pressure center - a result of the friction effect close to the surface.
18 Horizontal Motion and Weather The phenomena of weather are linked with the horizontal flow of air in other ways as well. In the midlatitudes chains of lows (cyclones) and highs (anticyclones) migrate steadily eastward mainly in winter. The overall tendency of air to rise over a low is combined with the advection of air by the circulation around it. Northerly winds bring cold air from the north southward to the west of the low-pressure center, and southerly winds bring warm air from the south northward. When cold and warm air masses meet, the warm air tends to move up creating favorable conditions for rain and severe weather. The bands along which air masses meet are called fronts.
19 Midlatitude Weather Systems
20 Life Cycle of Midlatitude Cyclones
21 Life Cycle and Heat Transport This three-dimensional schematic of a midlatitude cyclone life cycle demonstrates how these disturbances reduce the north-south temperature contrast in the midlatitudes by mixing cold air from the north with warm air from the south.
22 Tropical Weather Systems
23 Tropical Cyclones Tropical cyclones, also called hurricanes and typhoons, are intense low pressure disturbances that forms and migrates over the tropical ocean regions and are associated with intense winds and a very strong convective activity, which brings thunderstorms and large amounts of rainfall. They have the potential to cause major damage and loss of life when they make landfall.
24 Hurricane Vertical Cross Section The massive disturbances that sometimes grows in a time frame of a week or so, need specific and favorable conditions to occur, such as high sea surface temperatures (at lease 26 C) and weak vertical wind shears. Once they do, they spreads over a radius of a few hundred kilometers. Hurricanes are surrounded by rings of towering thunder clouds spiraling up to a small circle at the center of the storm, with a radius of km. Here the winds can reach a speed of 100 km/hour and more and the most intense rainfall occurs. Inside this ring lies the eye of the storm, where the air is still and the convection is suppressed by slow downward motion (subsidence).
25 Regions of Hurricane Activity Hurricanes are active in the "trade wind" belts - the regions just north or south of the equator where the winds blow quite steadily from east to west (easterlies). Here tropical disturbances generally form, initiated by weak pressure perturbations that exist all the time in the tropics. They move west with the trade winds in a steady, relatively slow motion (10-20 km/hour). During this phase they intensify mainly through the release of latent heat in the surrounding clouds and a small percentage reach full hurricane intensity. Hurricanes tracks curve eastward and they speed up north of ~30 N
26 Intertropical Convergence Zone (ITCZ) In the tropics, a belt of warmest surface temperatures, surrounds the Earth. Here there is abundant moisture so that small vertical movements of air can lead to spontaneous generation of deep convection. This convection then organizes itself in cells of massive thunderstorms that tend to drift eastward carried in the prevailing winds and in weak wave disturbances somewhat resembling midlatitude disturbances. This region is the ITCZ.
27
General Circulation. Nili Harnik DEES, Lamont-Doherty Earth Observatory
General Circulation Nili Harnik DEES, Lamont-Doherty Earth Observatory nili@ldeo.columbia.edu Latitudinal Radiation Imbalance The annual mean, averaged around latitude circles, of the balance between the
More informationThe dynamics of high and low pressure systems
The dynamics of high and low pressure systems Newton s second law for a parcel of air in an inertial coordinate system (a coordinate system in which the coordinate axes do not change direction and are
More informationThe atmosphere in motion: forces and wind. AT350 Ahrens Chapter 9
The atmosphere in motion: forces and wind AT350 Ahrens Chapter 9 Recall that Pressure is force per unit area Air pressure is determined by the weight of air above A change in pressure over some distance
More informationGeneral Atmospheric Circulation
General Atmospheric Circulation Take away Concepts and Ideas Global circulation: The mean meridional (N-S) circulation Trade winds and westerlies The Jet Stream Earth s climate zones Monsoonal climate
More informationMid-Latitude Cyclones and Fronts. Lecture 12 AOS 101
Mid-Latitude Cyclones and Fronts Lecture 12 AOS 101 Homework 4 COLDEST TEMPS GEOSTROPHIC BALANCE Homework 4 FASTEST WINDS L Consider an air parcel rising through the atmosphere The parcel expands as it
More informationDivergence, Spin, and Tilt. Convergence and Divergence. Midlatitude Cyclones. Large-Scale Setting
Midlatitude Cyclones Equator-to-pole temperature gradient tilts pressure surfaces and produces westerly jets in midlatitudes Waves in the jet induce divergence and convergence aloft, leading to surface
More information- tornadoes. Further Reading: Chapter 08 of the text book. Outline. - cyclones and anti-cyclones. -tropical storms. -Storm surge
(1 of 16) Further Reading: Chapter 08 of the text book Outline - cyclones and anti-cyclones - tornadoes -tropical storms -Storm surge (2 of 16) Introduction Previously, We talked about fronts and their
More informationControl Volume. Dynamics and Kinematics. Basic Conservation Laws. Lecture 1: Introduction and Review 1/24/2017
Lecture 1: Introduction and Review Dynamics and Kinematics Kinematics: The term kinematics means motion. Kinematics is the study of motion without regard for the cause. Dynamics: On the other hand, dynamics
More informationLecture 1: Introduction and Review
Lecture 1: Introduction and Review Review of fundamental mathematical tools Fundamental and apparent forces Dynamics and Kinematics Kinematics: The term kinematics means motion. Kinematics is the study
More informationThe Planetary Circulation System
12 The Planetary Circulation System Learning Goals After studying this chapter, students should be able to: 1. describe and account for the global patterns of pressure, wind patterns and ocean currents
More information- tornadoes. Further Reading: Chapter 08 of the text book. Outline. -tropical storms. -Storm surge
(1 of 12) Further Reading: Chapter 08 of the text book Outline - tornadoes -tropical storms -Storm surge (2 of 12) Introduction Previously, We talked about fronts and their relationship to air masses Also
More informationChapter 24 Tropical Cyclones
Chapter 24 Tropical Cyclones Tropical Weather Systems Tropical disturbance a cluster of thunderstorms about 250 to 600 km in diameter, originating in the tropics or sub-tropics Tropical depression a cluster
More information1/3/2011. This course discusses the physical laws that govern atmosphere/ocean motions.
Lecture 1: Introduction and Review Dynamics and Kinematics Kinematics: The term kinematics means motion. Kinematics is the study of motion without regard for the cause. Dynamics: On the other hand, dynamics
More informationHurricanes. April 14, 2009
Tropical Weather & Hurricanes Chapter 15 April 14, 2009 Tropical meteorology Tropics characterized by seasonal wet and drier periods- wet when sun is nearly overhead at noon and inter-tropical convergence
More informationLecture 18 Hurricanes
Lecture 18 Hurricanes Part I Structure and Climatology What is a hurricane? What is the structure or anatomy of a hurricane? How to build a hurricane - hurricane energy Hurricane climatology - when and
More informationF = ma. ATS 150 Global Climate Change Winds and Weather. Scott Denning CSU CMMAP 1. Please read Chapter 6 from Archer Textbook
Winds and Weather Please read Chapter 6 from Archer Textbook Circulation of the atmosphere and oceans are driven by energy imbalances Energy Imbalances What Makes the Wind Blow? Three real forces (gravity,
More informationExamples of Pressure Gradient. Pressure Gradient Force. Chapter 7: Forces and Force Balances. Forces that Affect Atmospheric Motion 2/2/2015
Chapter 7: Forces and Force Balances Forces that Affect Atmospheric Motion Fundamental force - Apparent force - Pressure gradient force Gravitational force Frictional force Centrifugal force Forces that
More informationTrue or false: The atmosphere is always in hydrostatic balance. A. True B. False
Clicker Questions and Clicker Quizzes Clicker Questions Chapter 7 Of the four forces that affect the motion of air in our atmosphere, which is to thank for opposing the vertical pressure gradient force
More informationWeather Systems. Section
Section 1 12.2 Objectives Compare and contrast the three major wind systems. Identify four types of fronts. Distinguish between highand low-pressure systems. Review Vocabulary convection: the transfer
More informationChapter 10 Atmospheric Forces & Winds
Chapter 10 Atospheric Forces & Winds Chapter overview: Atospheric Pressure o Horizontal pressure variations o Station vs sea level pressure Winds and weather aps Newton s 2 nd Law Horizontal Forces o Pressure
More informationAtmospheric Pressure and Wind Frode Stordal, University of Oslo
Chapter 4 Lecture Understanding Weather and Climate Seventh Edition Atmospheric Pressure and Wind Frode Stordal, University of Oslo Redina L. Herman Western Illinois University The Concept of Pressure
More informationChapter 24. Tropical Cyclones. Tropical Cyclone Classification 4/19/17
Chapter 24 Tropical Cyclones Tropical Cyclones Most destructive storms on the planet Originate over tropical waters, but their paths often take them over land and into midlatitudes Names Hurricane (Atlantic
More information5 Atmospheric Disturbances 7 1.Cyclones- tropical and temperate and associated weather conditions. 2.Anticyclones and associated weather conditions.
5 Atmospheric Disturbances 7 1.Cyclones- tropical and temperate and associated weather conditions. 2.Anticyclones and associated weather conditions. atmospheric disturbances (weather systems) that are
More informationWinds and Global Circulation
Winds and Global Circulation Atmospheric Pressure Winds Global Wind and Pressure Patterns Oceans and Ocean Currents El Nino How is Energy Transported to its escape zones? Both atmospheric and ocean transport
More informationWind: Global Systems Chapter 10
Wind: Global Systems Chapter 10 General Circulation of the Atmosphere General circulation of the atmosphere describes average wind patterns and is useful for understanding climate Over the earth, incoming
More informationLecture 2. Lecture 1. Forces on a rotating planet. We will describe the atmosphere and ocean in terms of their:
Lecture 2 Lecture 1 Forces on a rotating planet We will describe the atmosphere and ocean in terms of their: velocity u = (u,v,w) pressure P density ρ temperature T salinity S up For convenience, we will
More informationTransient and Eddy. Transient/Eddy Flux. Flux Components. Lecture 3: Weather/Disturbance. Transient: deviations from time mean Time Mean
Lecture 3: Weather/Disturbance Transients and Eddies Climate Roles Mid-Latitude Cyclones Tropical Hurricanes Mid-Ocean Eddies Transient and Eddy Transient: deviations from time mean Time Mean Eddy: deviations
More informationWeather Notes. Chapter 16, 17, & 18
Weather Notes Chapter 16, 17, & 18 Weather Weather is the condition of the Earth s atmosphere at a particular place and time Weather It is the movement of energy through the atmosphere Energy comes from
More informationb. The boundary between two different air masses is called a.
NAME Earth Science Weather WebQuest Part 1. Air Masses 1. Find out what an air mass is. http://okfirst.mesonet.org/train/meteorology/airmasses.html a. What is an air mass? An air mass is b. The boundary
More informationExamples of Pressure Gradient. Pressure Gradient Force. Chapter 7: Forces and Force Balances. Forces that Affect Atmospheric Motion 2/7/2019
Chapter 7: Forces and Force Balances Forces that Affect Atmospheric Motion Fundamental force - Apparent force - Pressure gradient force Gravitational force Frictional force Centrifugal force Forces that
More informationWeather is the of the Earth s atmosphere at a place and time. It is the movement of through the atmosphere o Energy comes from the
Weather Notes Weather Weather is the of the Earth s atmosphere at a place and time It is the movement of through the atmosphere o Energy comes from the The sun is the force that weather The sun s energy
More informationAtmospheric Circulation
Atmospheric Circulation Introductory Oceanography Instructor: Ray Rector Atmospheric Circulation Key Topics Composition and Structure Solar Heating and Convection The Coriolis Effect Global Wind Patterns
More informationMeasurement of Rotation. Circulation. Example. Lecture 4: Circulation and Vorticity 1/31/2017
Lecture 4: Circulation and Vorticity Measurement of Rotation Circulation Bjerknes Circulation Theorem Vorticity Potential Vorticity Conservation of Potential Vorticity Circulation and vorticity are the
More informationGo With the Flow From High to Low Investigating Isobars
Go With the Flow From High to Low Investigating Isobars Science 10 Mrs. Purba Air Masses The air over a warm surface can be heated, causing it to rise above more dense air. The result is the formation
More information4. Atmospheric transport. Daniel J. Jacob, Atmospheric Chemistry, Harvard University, Spring 2017
4. Atmospheric transport Daniel J. Jacob, Atmospheric Chemistry, Harvard University, Spring 2017 Forces in the atmosphere: Gravity g Pressure-gradient ap = ( 1/ ρ ) dp / dx for x-direction (also y, z directions)
More informationLecture 1. Equations of motion - Newton s second law in three dimensions. Pressure gradient + force force
Lecture 3 Lecture 1 Basic dynamics Equations of motion - Newton s second law in three dimensions Acceleration = Pressure Coriolis + gravity + friction gradient + force force This set of equations is the
More informationTropical Cyclones. Objectives
Tropical Cyclones FIU Undergraduate Hurricane Internship Lecture 2 8/8/2012 Objectives From this lecture you should understand: Global tracks of TCs and the seasons when they are most common General circulation
More informationGlobal Wind Patterns
Name: Earth Science: Date: Period: Global Wind Patterns 1. Which factor causes global wind patterns? a. changes in the distance between Earth and the Moon b. unequal heating of Earth s surface by the Sun
More informationName Period 4 th Six Weeks Notes 2013 Weather
Name Period 4 th Six Weeks Notes 2013 Weather Radiation Convection Currents Winds Jet Streams Energy from the Sun reaches Earth as electromagnetic waves This energy fuels all life on Earth including the
More informationHurricanes Part I Structure and Climatology by Professor Steven Businger. Hurricane Katrina
Hurricanes Part I Structure and Climatology by Professor Steven Businger Hurricane Katrina Hurricanes Part I Structure and Climatology by Professor Steven Businger What is a hurricane? What is the structure
More informationThe Transfer of Heat
The Transfer of Heat Outcomes: S2-4-03 Explain effects of heat transfer within the atmosphere and hydrosphere on the development and movement of wind and ocean currents. Coriolis Effect In our ecology
More information1/18/2011. Conservation of Momentum Conservation of Mass Conservation of Energy Scaling Analysis ESS227 Prof. Jin-Yi Yu
Lecture 2: Basic Conservation Laws Conservation Law of Momentum Newton s 2 nd Law of Momentum = absolute velocity viewed in an inertial system = rate of change of Ua following the motion in an inertial
More informationName SOLUTIONS T.A./Section Atmospheric Science 101 Homework #6 Due Thursday, May 30 th (in class)
Name SOLUTIONS T.A./Section Atmospheric Science 101 Homework #6 Due Thursday, May 30 th (in class) 1. General Circulation Briefly describe where each of the following features is found in the earth s general
More informationATMO 436a. The General Circulation. Redacted version from my NATS lectures because Wallace and Hobbs virtually ignores it
ATMO 436a The General Circulation Redacted version from my NATS lectures because Wallace and Hobbs virtually ignores it Scales of Atmospheric Motion vs. Lifespan The general circulation Atmospheric oscillations
More informationWeather, Air Masses, Fronts and Global Wind Patterns. Meteorology
Weather, Air Masses, Fronts and Global Wind Patterns Meteorology Weather is what conditions of the atmosphere are over a short period of time. Climate is how the atmosphere "behaves" over long periods
More informationClass exercises Chapter 3. Elementary Applications of the Basic Equations
Class exercises Chapter 3. Elementary Applications of the Basic Equations Section 3.1 Basic Equations in Isobaric Coordinates 3.1 For some (in fact many) applications we assume that the change of the Coriolis
More informationSpace Atmospheric Gases. the two most common gases; found throughout all the layers a form of oxygen found in the stratosphere
Earth s atmospheric layers Earth s atmosphere is the layer of gases that surrounds the planet and makes conditions on Earth suitable for living things. Layers Earth s atmosphere is divided into several
More informationESCI 241 Meteorology Lesson 19 Tropical Cyclones Dr. DeCaria
ESCI 241 Meteorology Lesson 19 Tropical Cyclones Dr. DeCaria READING: Chapter 16 GENERAL A tropical cyclone is a large, low-pressure system that forms over the tropical oceans. Tropical cyclones are classified
More informationLecture 14. Equations of Motion Currents With Friction Sverdrup, Stommel, and Munk Solutions Remember that Ekman's solution for wind-induced transport
Lecture 14. Equations of Motion Currents With Friction Sverdrup, Stommel, and Munk Solutions Remember that Ekman's solution for wind-induced transport is which can also be written as (14.1) i.e., #Q x,y
More informationIntroduction to Meteorology & Climate. Climate & Earth System Science. Atmosphere Ocean Interactions. A: Structure of the Ocean.
Climate & Earth System Science Introduction to Meteorology & Climate MAPH 10050 Peter Lynch Peter Lynch Meteorology & Climate Centre School of Mathematical Sciences University College Dublin Meteorology
More informationHurricanes. Hurricanes are large, tropical storm systems that form and develop over the warm waters near the equator.
Hurricanes Hurricanes are large, tropical storm systems that form and develop over the warm waters near the equator. They are responsible for weather that can devastate entire communities: Heavy rain --
More informationd v 2 v = d v d t i n where "in" and "rot" denote the inertial (absolute) and rotating frames. Equation of motion F =
Governing equations of fluid dynamics under the influence of Earth rotation (Navier-Stokes Equations in rotating frame) Recap: From kinematic consideration, d v i n d t i n = d v rot d t r o t 2 v rot
More information1/25/2010. Circulation and vorticity are the two primary
Lecture 4: Circulation and Vorticity Measurement of Rotation Circulation Bjerknes Circulation Theorem Vorticity Potential Vorticity Conservation of Potential Vorticity Circulation and vorticity are the
More informationLecture 5: Atmospheric General Circulation and Climate
Lecture 5: Atmospheric General Circulation and Climate Geostrophic balance Zonal-mean circulation Transients and eddies Meridional energy transport Moist static energy Angular momentum balance Atmosphere
More informationOcean currents: some misconceptions and some dynamics
Ocean currents: some misconceptions and some dynamics Joe LaCasce Dept. Geosciences October 30, 2012 Where is the Gulf Stream? BBC Weather Center Where is the Gulf Stream? Univ. Bergen news website (2011)
More informationCHAPTER 9 ATMOSPHERE S PLANETARY CIRCULATION MULTIPLE CHOICE QUESTIONS
CHAPTER 9 ATMOSPHERE S PLANETARY CIRCULATION MULTIPLE CHOICE QUESTIONS 1. Viewed from above in the Northern Hemisphere, surface winds about a subtropical high blow a. clockwise and inward. b. counterclockwise.
More informationSolution to Problems #1. I. Information Given or Otherwise Known. = 28 m/s. Heading of the ultralight aircraft!! h
METR 520: Atmospheric Dynamics II Dr. Dave Dempsey Dept. of Geosciences, SFSU Spring 2012 Solution to Problems 1 Problem 1 An ultralight aircraft is flying. I. Information Given or Otherwise Known Horizontal
More informationCHAPTER 2 - ATMOSPHERIC CIRCULATION & AIR/SEA INTERACTION
Chapter 2 - pg. 1 CHAPTER 2 - ATMOSPHERIC CIRCULATION & AIR/SEA INTERACTION The atmosphere is driven by the variations of solar heating with latitude. The heat is transferred to the air by direct absorption
More informationSurface Circulation. Key Ideas
Surface Circulation The westerlies and the trade winds are two of the winds that drive the ocean s surface currents. 1 Key Ideas Ocean water circulates in currents. Surface currents are caused mainly by
More informationGlobal Weather Trade Winds etc.notebook February 17, 2017
Global Weather 1 north pole northern hemisphere equator southern hemisphere south pole 2 We have seasons because of the Earth's tilt The seasons are opposite in the northern and southern hemispheres winter
More informationATSC 2000 Final Fall 2005
ATSC 2000 Final Fall 2005 true/false /25 multiple choice /25 short answer /23 essay /10 total /83 or % True/False Indicate whether the sentence or statement is true or false. (25 questions 1% each) 1.
More informationNWP Equations (Adapted from UCAR/COMET Online Modules)
NWP Equations (Adapted from UCAR/COMET Online Modules) Certain physical laws of motion and conservation of energy (for example, Newton's Second Law of Motion and the First Law of Thermodynamics) govern
More informationBalanced Flow Geostrophic, Inertial, Gradient, and Cyclostrophic Flow
Balanced Flow Geostrophic, Inertial, Gradient, and Cyclostrophic Flow The types of atmospheric flows describe here have the following characteristics: 1) Steady state (meaning that the flows do not change
More information1/18/2011. From the hydrostatic equation, it is clear that a single. pressure and height in each vertical column of the atmosphere.
Lecture 3: Applications of Basic Equations Pressure as Vertical Coordinate From the hydrostatic equation, it is clear that a single valued monotonic relationship exists between pressure and height in each
More informationWeather & Ocean Currents
Weather & Ocean Currents Earth is heated unevenly Causes: Earth is round Earth is tilted on an axis Earth s orbit is eliptical Effects: Convection = vertical circular currents caused by temperature differences
More informationwarmest (coldest) temperatures at summer heat dispersed upward by vertical motion Prof. Jin-Yi Yu ESS200A heated by solar radiation at the base
Pole Eq Lecture 3: ATMOSPHERE (Outline) JS JP Hadley Cell Ferrel Cell Polar Cell (driven by eddies) L H L H Basic Structures and Dynamics General Circulation in the Troposphere General Circulation in the
More informationPhysical Oceanography, MSCI 3001 Oceanographic Processes, MSCI Dr. Katrin Meissner Ocean Dynamics.
Physical Oceanography, MSCI 3001 Oceanographic Processes, MSCI 5004 Dr. Katrin Meissner k.meissner@unsw.e.au Ocean Dynamics The Equations of Motion d u dt = 1 ρ Σ F dt = 1 ρ ΣF x dt = 1 ρ ΣF y dw dt =
More informationNOTES Surface Weather Maps.notebook. April 05, atmospheric. rises. Coriolis. Coriolis. counterclockwise. counterclockwise. point. origin.
Surface Weather Maps L Symbol : Indicates an area of low air pressure (aka, pressure or pressure). Called a relatively barometric atmospheric cyclone Formation: As warm air in the center cyclone of a,
More informationTuesday, September 13, 16
Weather Weather State Objectives 4.c, 4.d, 4.h. Discussion What are some ways in which weather affects your everyday life? Discussion What are some ways in which weather affects your everyday life? What
More informationMeteorology Lecture 15
Meteorology Lecture 15 Robert Fovell rfovell@albany.edu 1 Important notes These slides show some figures and videos prepared by Robert G. Fovell (RGF) for his Meteorology course, published by The Great
More informationSEVERE AND UNUSUAL WEATHER
SEVERE AND UNUSUAL WEATHER Basic Meteorological Terminology Adiabatic - Referring to a process without the addition or removal of heat. A temperature change may come about as a result of a change in the
More informationConservation of Mass Conservation of Energy Scaling Analysis. ESS227 Prof. Jin-Yi Yu
Lecture 2: Basic Conservation Laws Conservation of Momentum Conservation of Mass Conservation of Energy Scaling Analysis Conservation Law of Momentum Newton s 2 nd Law of Momentum = absolute velocity viewed
More informationAir Masses, Weather Systems and Hurricanes
The Earth System - Atmosphere IV Air Masses, Weather Systems and Hurricanes Air mass a body of air which takes on physical characteristics which distinguish it from other air. Classified on the basis of
More informationPart-8c Circulation (Cont)
Part-8c Circulation (Cont) Global Circulation Means of Transfering Heat Easterlies /Westerlies Polar Front Planetary Waves Gravity Waves Mars Circulation Giant Planet Atmospheres Zones and Belts Global
More informationClimate versus Weather
Climate versus Weather What is climate? Climate is the average weather usually taken over a 30-year time period for a particular region and time period. Climate is not the same as weather, but rather,
More informationATMOSPHERIC CIRCULATION
CHAPTER ATMOSPHERIC CIRCULATION AND WEATHER SYSTEMS E arlier Chapter 9 described the uneven distribution of temperature over the surface of the earth. Air expands when heated and gets compressed when cooled.
More informationWaves and Weather. 1. Where do waves come from? 2. What storms produce good surfing waves? 3. Where do these storms frequently form?
Waves and Weather 1. Where do waves come from? 2. What storms produce good surfing waves? 3. Where do these storms frequently form? 4. Where are the good areas for receiving swells? Where do waves come
More informationa reference frame that accelerates in a straight line a reference frame that moves along a circular path Straight Line Accelerated Motion
1.12.1 Introduction Go back to lesson 9 and provide bullet #3 In today s lesson we will consider two examples of non-inertial reference frames: a reference frame that accelerates in a straight line a reference
More informationLecture 10 March 15, 2010, Monday. Atmospheric Pressure & Wind: Part 1
Lecture 10 March 15, 2010, Monday Atmospheric Pressure & Wind: Part 1 Speed, Velocity, Acceleration, Force, Pressure Atmospheric Pressure & Its Measurement Ideal Gas Law (Equation of State) Pressure Gradient
More informationAtmosphere, Ocean and Climate Dynamics Answers to Chapter 8
Atmosphere, Ocean and Climate Dynamics Answers to Chapter 8 1. Consider a zonally symmetric circulation (i.e., one with no longitudinal variations) in the atmosphere. In the inviscid upper troposphere,
More informationWhat a Hurricane Needs to Develop
Weather Weather is the current atmospheric conditions, such as air temperature, wind speed, wind direction, cloud cover, precipitation, relative humidity, air pressure, etc. 8.10B: global patterns of atmospheric
More information(April 7, 2010, Wednesday) Tropical Storms & Hurricanes Part 2
Lecture #17 (April 7, 2010, Wednesday) Tropical Storms & Hurricanes Part 2 Hurricane Katrina August 2005 All tropical cyclone tracks (1945-2006). Hurricane Formation While moving westward, tropical disturbances
More informationSPI Analyze data to identify events associated with heat convection in the atmosphere. SPI Recognize the connection between the
SPI 0607.8.1 - Analyze data to identify events associated with heat convection in the atmosphere. SPI 0607.8.2 - Recognize the connection between the sun s energy and the wind. o Energy from the Sun creates
More informationTPFEL: Ch. 8: Torque and Angular Momentum (cont d)
TPFEL: Ch. 8: Torque and Angular Momentum (cont d) 8.1: The spinning skater 1 To illustrate this complicated stuff consider, first, a spinning ice skater (Fig. 8.1). She begins her spin (by generating
More informationnot to be republished NCERT ATMOSPHERIC CIRCULATION AND WEATHER SYSTEMS ATMOSPHERIC PRESSURE
CHAPTER E arlier Chapter 9 described the uneven distribution of temperature over the surface of the earth. Air expands when heated and gets compressed when cooled. This results in variations in the atmospheric
More informationMIDTERM 1: APPROXIMATE GRADES TOTAL POINTS = 45 AVERAGE = 33 HIGH SCORE = = A = B = C < 20.0 NP
MIDTERM 1: TOTAL POINTS = 45 AVERAGE = 33 HIGH SCORE = 43 APPROXIMATE GRADES 38.0 45.0 = A 30.0 37.5 = B 20.0 29.5 = C < 20.0 NP Forces to consider: 1) Pressure Gradient Force 2) Coriolis Force 3) Centripetal
More informationThe Circulation of the Atmosphere:
The Circulation of the Atmosphere: Laboratory Experiments (see next slide) Fluid held in an annular container is at rest and is subjected to a temperature gradient. The less dense fluid near the warm wall
More informationVertical Structure of Atmosphere
ATMOS 3110 Introduction to Atmospheric Sciences Distribution of atmospheric mass and gaseous constituents Because of the earth s gravitational field, the atmosphere exerts a downward forces on the earth
More informationNote that Rossby waves are tranverse waves, that is the particles move perpendicular to the direction of propagation. f up, down (clockwise)
Ocean 423 Rossby waves 1 Rossby waves: Restoring force is the north-south gradient of background potential vorticity (f/h). That gradient can be due to either the variation in f with latitude, or to a
More informationHurricanes are intense vortical (rotational) storms that develop over the tropical oceans in regions of very warm surface water.
Hurricanes: Observations and Dynamics Houze Section 10.1. Holton Section 9.7. Emanuel, K. A., 1988: Toward a general theory of hurricanes. American Scientist, 76, 371-379 (web link). http://ww2010.atmos.uiuc.edu/(gh)/guides/mtr/hurr/home.rxml
More informationQuiz 2 Review Questions
Quiz 2 Review Questions Chapter 7 Lectures: Winds and Global Winds and Global Winds cont 1) What is the thermal circulation (thermal wind) and how does it form? When we have this type of circulation, how
More informationAtmospheric circulation
Atmospheric circulation Trade winds http://science.nasa.gov/science-news/science-at-nasa/2002/10apr_hawaii/ Atmosphere (noun) the envelope of gases (air) surrounding the earth or another planet Dry air:
More informationSynoptic Meteorology II: Self-Development in the IPV Framework. 5-7 May 2015
Synoptic Meteorology II: Self-Development in the IPV Framework 5-7 May 2015 Readings: Section 5.3.6 of Midlatitude Synoptic Meteorology. Introduction In this and other recent lectures, we have developed
More informationClimate vs. Weather. Weather: Short term state of the atmosphere. Climate: The average weather conditions in an area over a long period of time
Weather and Climate Climate vs. Weather Weather: Short term state of the atmosphere. Temperature, humidity, cloud cover, precipitation, winds, visibility, air pressure, air pollution, etc Climate: The
More informationUse the terms from the following list to complete the sentences below. Each term may be used only once.
Skills Worksheet Directed Reading Section: Air Masses Use the terms from the following list to complete the sentences below. Each term may be used only once. high pressure poles low pressure equator wind
More informationTemperature (T) degrees Celsius ( o C) arbitrary scale from 0 o C at melting point of ice to 100 o C at boiling point of water Also (Kelvin, K) = o C
1 2 3 4 Temperature (T) degrees Celsius ( o C) arbitrary scale from 0 o C at melting point of ice to 100 o C at boiling point of water Also (Kelvin, K) = o C plus 273.15 0 K is absolute zero, the minimum
More informationDEPARTMENT OF EARTH & CLIMATE SCIENCES SAN FRANCISCO STATE UNIVERSITY EARTH 365. Fall 2018 Test #2. November :00pm 7:15pm
1 DEPARTMENT OF EARTH & CLIMATE SCIENCES SAN FRANCISCO STATE UNIVERSITY EARTH 365 Fall 2018 Test #2 November 6 2018 6:00pm 7:15pm 200 points (4 points each answer) Answer on the answer sheet provided.
More informationIntroduction to Atmospheric Circulation
Introduction to Atmospheric Circulation Start rotating table Cloud Fraction Dice Results from http://eos.atmos.washington.edu/erbe/ from http://eos.atmos.washington.edu/erbe/ from http://eos.atmos.washington.edu/erbe/
More informationESS314. Basics of Geophysical Fluid Dynamics by John Booker and Gerard Roe. Conservation Laws
ESS314 Basics of Geophysical Fluid Dynamics by John Booker and Gerard Roe Conservation Laws The big differences between fluids and other forms of matter are that they are continuous and they deform internally
More information1. Sea Surface Temperatures (SSTs) > 27 and extending to some depth.
Formation Factors for Hurricanes 1. Sea Surface Temperatures (SSTs) > 27 and extending to some depth. 2. Location >5 away from the equator (usually 10 ). Coriolis force is necessary for rotation. 3. High
More information