Downslope Wind Storms

Size: px
Start display at page:

Download "Downslope Wind Storms"

Transcription

1 Downslope Wind Storms

2 How does acceleration over the wing affect pressure field? Equation of Motion for frictionless flow: V t = l k α p+g If we assume a horizontally homogeneous, hydrostatic reference state where subsrript "o": and so, subtracting: V t = l k α o p+α '/α o g α o p o / z= g where primes are deviations from base state. Integrate equations of motion for frictionless flow along the trajectory of the flow ( ds): s V t ds= l s α o p' ds s s ds k ds ( α '/α o )g ds Allow only for flow in x/z plane, assume Lamb vector is small ( l: 0), s and flow is steady state V t = 0, and then we get Bernouli's equation 1/ 2 V 2 + ( α '/α o )gz+ α o d s p s

3 Flow Mountain Ridge Infinitely long mountain, no flow around ridge Consider first an airplane wing: α '/α o g = α o p'/ s

4 Small Ridge Similar to airplane wing: α '/α o g = α o p'/ s

5 Meso-Beta Scale Ridge Resonant gravity response is involved, low pressure shifts increasingly down stream as the scale of the ridge becomes larger: α '/α o g : α o p'/ s

6 Witch of Agnesi Ridge Lets consider a Witch of Agnesi, bell shaped mountain (normally used for analytical mountain wave studies) having the formula: a 2 z s = h a 2 + d 2 a is the half-width, h is the maximum height, and d is the distance from the ridge top, and z_s is the topography height.

7 More about Witch of Agnesi Easy for analytical solutions NOT a sine wave, is a bell shaped ridge that contains a spectrum of wave components representing many wavelengths Some parts of the ridge may be at super Rossby radius scale and some may be at sub-rossby radius scale for instance

8 Froude Number Important influences on atmosphere response to flow over an object: (a) Length scale of the object (N) Brunt-Vasallai frequency, the vertical stability providing a restoring force for gravity waves: N g θ = θ z (U) velocity of flow normal to the ridge 1 2

9 Froude Number Define Froude Number: F r inertial frequency U / a = = Brunt-Vasallai Frequency N

10 Inertial Cutoff, ie Rossby Number The coriolis parameter is another important parameter. If the mountain is big enough, we get lee cyclogenesis, not gravity waves! So we must consider the Rossby Number, ie: R o = a L R

11 Flow Over a Ridge We consider flow over shallow (h << depth of troposphere) ridges of several half-widths and look at the results of a linear analytical solution for the Witch of Agnesi mountain. The solution to the linear problem yields a wave equation of the form: w- vertical velocity z- height above surface k vertical wave number l Scorer Parameter ( 2 2 ) w + l k w = tt zz 0

12 Vertical Wave Number L_x is the horizontal wavelength of the gravity wave. This parameter in the vertical wave equation is purely nonhydrostatic! k = 2 π L x

13 Scorer Parameter This parameter is related to the transmissivity of the atmosphere to gravity waves considering only hydrostatic processes l N 1 d U = U 2 U dz 2

14 When Gravity Waves? Gravity wave solutions only exist when 2 2 l k > Therefore, there is a short wave cutoff scale, below which gravity waves cannot exist: L_z is the vertical wavelength of the gravity wave L_x is the horizontal wavelength of the gravity wave 0 π π 2 2 z x L L = > l 2 k 2 l

15 Narrow Ridge: Evanescent waves

16 Medium Ridge: Mountain (gravity) waves

17 Typical Mountain Wave (Lenticular) Cloud

18 Mountain Wave Lenticular Cloud

19

20 Double Wave (Lenticular) Cloud

21 Flying Saucer Wave Cloud

22 Lenticular Cloud

23

24 Broad Ridge: Lee Cyclogenesis for larger modes, GW for smaller modes

25 Medium-Narrow ridge, but with Scorer Parameter (l) varying with height. This traps shorter waves of the Witch of Agnesi mountain, but transmitts vertically the longer ones, leading to lee waves. - This is mostly a nonhydrostatic effect why? - The shorter waves have solutions in low levels where l is large, but do not above, so they reflect off

26 Lee Waves

27 Lee Waves

28 Mountain (Gravity) Waves F << 1 ; i.e. static stability dominates r over inertia R > 1 or L < L ; i.e. effect of stability o x R dominates over Coriolis L > 2 π / l x, i.e. scale is larger than shortwave cutoff for gravity waves

29 Vertically Propagating Gravity Waves

30

31 Gravity wave absorbed at critical level where phase speed equals wind speed and air statically stable above

32 Effect of moisture on Mountain Waves Effect is to lessen the Brunt Vasallai frequency because latent heat reduces lapse rate: L vl r s RT ln θ L vl r s r l N moist = g 2 + ε L vl r s z c p T z z c p RT

33 Increases depth of mountain wave Increases horizontal wavelength May cause some trapping of shorter wavelengths

34 Theory of Downslope Wind Storms They go by a number of names: Chinook winds (Rockies, Indian name that means snow eater Foehn wind, name used in Europe Santa Ana wind, name used in Southern California

35 Downslope wind storms are related to mountain waves Mountain waves will locally incrrease the winds on the lee side of the mountain, but typically not to severe levels But in downslope wind cases they get very strong reaching severe levels routinely (> 55 kts) Lets look at a famous documented windstorm hitting Boulder Colorado on 11 January, 1972

36

37

38

39 Klemp and Lilly Theory Based on hydrostatic simulations Partial reflection of group velocity off of tropopause creating resonance Need tropopause height to be integer number of half wavelengths above surface Resonance increases amplitude of mountain wave no wave breaking in their hydrostatic theory

40

41 Clark and Pelteir (1977) Same effect but upper wave breaks The breaking upper wave destabilizes upper troposphere and lower stratosphere ducting the underlying mountain wave more Strong amplification of lower troposphere wave Critical level at ¾ L z optimal

42

43

44 Influence of Mid-Level Inversion Created by a cold pool to the west and to the east, such as a Great Basin High to west of Rockies and Arctic High to east Inversion near or just above ridge top Inversion traps wave energy below, leading to large amplification down low and formation of a hydraulic jump

45 Hydraulic Jump Analogy Current thinking among mountain meteorologists Imagine flow along a rocky stream bed: Water under air is analogous to the layer of cold stable air at the surface under less stable air above! Notice the water waves are trapped from moving upward into the air as the waves in the stable layer of air are trapped from moving upward into the less stable air. When water is much deeper than rocks, turbulence, water flows across the rocks with little turbulence. You could take a boring raft trip down such a laminar stream.

46 Now imagine that the water lowers to be just deeper than the rocks. Now you have whitewater! The water plunges down the lee side of the rocks and even digs a little hole, depressing the surface and blowing out rocks etc. The same is true for the downslope wind. Trapped beneath the inversion, the wave amplifies and breaks, clowing out Boulder!

47

48

49

50 Wind Speed 1400 UTC Potential Temperature Class Case Study: February 3, 1999 west of Boulder

51

ESCI 343 Atmospheric Dynamics II Lesson 10 - Topographic Waves

ESCI 343 Atmospheric Dynamics II Lesson 10 - Topographic Waves ESCI 343 Atmospheric Dynamics II Lesson 10 - Topographic Waves Reference: An Introduction to Dynamic Meteorology (3 rd edition), J.R. Holton Reading: Holton, Section 7.4. STATIONARY WAVES Waves will appear

More information

Gravity waves and bores. Material kindly provided by Dr. Steven Koch GSD NOAA (Boulder, CO)

Gravity waves and bores. Material kindly provided by Dr. Steven Koch GSD NOAA (Boulder, CO) Gravity waves and bores Material kindly provided by Dr. Steven Koch GSD NOAA (Boulder, CO) Presented at Iowa State University 11 April 2005 What is a gravity wave? An oscillation caused by the displacement

More information

Modeling of Mountain Waves in T-REX

Modeling of Mountain Waves in T-REX 10.6 Modeling of Mountain Waves in T-REX Steven E. Koch 1,2, Ligia R. Bernardet 1,2, Brian D. Jamison 1,3, and John M. Brown 1 1 NOAA / Earth Systems Research Laboratory (ESRL), Boulder, Colorado 2 Developmental

More information

A new theory for downslope windstorms and trapped lee wave François Lott Lab. Météorologie Dynamique, Ecole Normale Supérieure, Paris

A new theory for downslope windstorms and trapped lee wave François Lott Lab. Météorologie Dynamique, Ecole Normale Supérieure, Paris A new theory for downslope windstorms and trapped lee wave François Lott Lab. Météorologie Dynamique, Ecole Normale Supérieure, Paris 1)Motivation: trapped lee waves 2)Model description 3)Downslope windstorms

More information

Trapped lee waves: a currently neglected source of low-level orographic drag

Trapped lee waves: a currently neglected source of low-level orographic drag Trapped lee waves: a currently neglected source of low-level orographic drag Miguel A. C. Teixeira, Jose L. Argain, Pedro M. A. Miranda 3, University of Reading, Reading, UK Physics, University of Algarve,

More information

Gravity waves in stable atmospheric boundary layers

Gravity waves in stable atmospheric boundary layers Gravity waves in stable atmospheric boundary layers Carmen J. Nappo CJN Research Meteorology Knoxville, Tennessee 37919, USA Abstract Gravity waves permeate the stable atmospheric planetary boundary layer,

More information

18 Flight Hazards over High Ground

18 Flight Hazards over High Ground 18 Flight Hazards over High Ground meteorology 18.1 Mountain Effect on Fronts When a warm front passes a mountain range, the air, is lifted over the mountain and will strengthen the formation of cloud

More information

VI. Static Stability. Consider a parcel of unsaturated air. Assume the actual lapse rate is less than the dry adiabatic lapse rate: Γ < Γ d

VI. Static Stability. Consider a parcel of unsaturated air. Assume the actual lapse rate is less than the dry adiabatic lapse rate: Γ < Γ d VI. Static Stability Consider a parcel of unsaturated air. Assume the actual lapse rate is less than the dry adiabatic lapse rate: Γ < Γ d VI. Static Stability Consider a parcel of unsaturated air. Assume

More information

Selected Papers on Downslope Windstorms

Selected Papers on Downslope Windstorms Selected Papers on Downslope Windstorms JONATHAN VIGH Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado February 20, 2005 1. Introduction This purpose of this note is

More information

Local Winds. Please read Ahrens Chapter 10

Local Winds. Please read Ahrens Chapter 10 Local Winds Please read Ahrens Chapter 10 Scales of Motion Microscale: meters Turbulent eddies Formed by mechanical disturbance or convection Lifetimes of minutes Mesoscale: km s to 100 s of km s Local

More information

Wind: Small-scale and Local Systems

Wind: Small-scale and Local Systems Wind: Small-scale and Local Systems Scales of Atmospheric Motion Atmospheric motions/phenomena occur on many diverse spatial and temporal scales. Weather forecasters tend to focus on Mesoscale and synoptic

More information

LOCAL WINDS. Prof. Stephan De Wekker Department of Env. Sciences Guest lecture EVSC 1300

LOCAL WINDS. Prof. Stephan De Wekker Department of Env. Sciences Guest lecture EVSC 1300 LOCAL WINDS Prof. Stephan De Wekker (dewekker@virginia.edu) Department of Env. Sciences Guest lecture EVSC 1300 SEA BREEZE 980 mb 990 mb 1000 mb LAND BREEZE The convergence of two lake breezes and

More information

Geophysical Fluid Dynamics of the Earth. Jeffrey B. Weiss University of Colorado, Boulder

Geophysical Fluid Dynamics of the Earth. Jeffrey B. Weiss University of Colorado, Boulder Geophysical Fluid Dynamics of the Earth Jeffrey B. Weiss University of Colorado, Boulder The Earth is a spinning sphere Coriolis force depends on latitude solar flux depends on latitude Michael Ritter,

More information

2.4. Applications of Boundary Layer Meteorology

2.4. Applications of Boundary Layer Meteorology 2.4. Applications of Boundary Layer Meteorology 2.4.1. Temporal Evolution & Prediction of the PBL Earlier, we saw the following figure showing the diurnal evolution of PBL. With a typical diurnal cycle,

More information

Atmospheric & Ocean Circulation-

Atmospheric & Ocean Circulation- Atmospheric & Ocean Circulation- Overview: Atmosphere & Climate Atmospheric layers Heating at different latitudes Atmospheric convection cells (Hadley, Ferrel, Polar) Coriolis Force Generation of winds

More information

Upstream-Propagating Wave Modes in Moist and Dry Flow over Topography

Upstream-Propagating Wave Modes in Moist and Dry Flow over Topography 3060 J O U R N A L O F T H E A T M O S P H E R I C S C I E N C E S VOLUME 69 Upstream-Propagating Wave Modes in Moist and Dry Flow over Topography TEDDIE L. KELLER, RICHARD ROTUNNO, MATTHIAS STEINER, AND

More information

Meteorology Lecture 17

Meteorology Lecture 17 Meteorology Lecture 17 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 information

1. Large-scale temperature inversions.

1. Large-scale temperature inversions. Lecture 18. Local and regional pollution issues: plumes of pollution. Objectives: 1. Large-scale temperature inversions. 2. Plumes of pollution. Readings: Turco: p.128-135; Brimblecombe: p.130-138 1. Large-scale

More information

The total precipitation (P) is determined by the average rainfall rate (R) and the duration (D),

The total precipitation (P) is determined by the average rainfall rate (R) and the duration (D), Orographic precipitation Common ingredients of heavy orographic precipitation The total precipitation (P) is determined by the average rainfall rate (R) and the duration (D), P = RD. (1) The rainfall rate

More information

Thorsten Mauritsen *, Gunilla Svensson Stockholm University, Stockholm, Sweden

Thorsten Mauritsen *, Gunilla Svensson Stockholm University, Stockholm, Sweden J.1 WAVE FLOW SIMULATIONS OVER ARCTIC LEADS Thorsten Mauritsen *, Gunilla Svensson Stockholm University, Stockholm, Sweden Branko Grisogono Department of Geophysics, Faculty of Science, Zagreb, Croatia

More information

Turbulence forecasts based on upper-air soundings

Turbulence forecasts based on upper-air soundings OC3570 Turbulence forecasts based on upper-air soundings By Greg Ireton Introduction The objective of this paper is to make turbulence forecasts from upper-air data by making Richardson s number calculations

More information

Mountain Forced Flows

Mountain Forced Flows Mountain Forced Flows Jeremy A. Gibbs University of Oklahoma gibbz@ou.edu February 3, 2015 1 / 45 Overview Orographic Precipitation Common Ingredients of Heavy Orographic Precipitation Formation and Enhancement

More information

ATMOSPHERIC CIRCULATION. WIND = The horizontal movement of air. Results from the differences in air pressure. Always moves from HIGH to LOW.

ATMOSPHERIC CIRCULATION. WIND = The horizontal movement of air. Results from the differences in air pressure. Always moves from HIGH to LOW. ATMOSPHERIC CIRCULATION WIND = The horizontal movement of air. Results from the differences in air pressure. Always moves from HIGH to LOW. Pressure differences result from variations in temperature. AIR

More information

Chapter 4. Convec.on Adiaba.c lapse rate

Chapter 4. Convec.on Adiaba.c lapse rate Chapter 4 Convec.on Adiaba.c lapse rate 1.Outline: a. air parcel theory, adiabatic processes b. how do we define/determine atmospheric stability? 2.Readings: Chapter 4 VERTICAL STRUCTURE T STRATIFICATION

More information

Meteorology I Pre test for the Second Examination

Meteorology I Pre test for the Second Examination Meteorology I Pre test for the Second Examination MULTIPLE CHOICE 1. A primary reason why land areas warm up more rapidly than water areas is that a) on land, all solar energy is absorbed in a shallow

More information

Abrupt marine boundary layer changes revealed by airborne in situ and lidar measurements

Abrupt marine boundary layer changes revealed by airborne in situ and lidar measurements Abrupt marine boundary layer changes revealed by airborne in situ and lidar measurements David A. Rahn 1, Thomas R. Parish 2, and David Leon 2 1 Univeristy of Kansas 2 Univeristy of Wyoming Precision Atmospheric

More information

Civil Air Patrol Auxiliary of the United States Air Force

Civil Air Patrol Auxiliary of the United States Air Force Mountain Flying Qualification Course Civil Air Patrol Auxiliary of the United States Air Force Mountain Weather Slopes Most U.S. mountain ranges are oriented north-south, while the prevailing winds are

More information

Envs, Geol, Phys 112: Global Climate. Energy-Atmosphere System Review Aguado & Bert, Ch. 1, 2, 3, 4, 5, 6, 9, 10

Envs, Geol, Phys 112: Global Climate. Energy-Atmosphere System Review Aguado & Bert, Ch. 1, 2, 3, 4, 5, 6, 9, 10 Exam 1 Review Energy-Atmosphere System Review Aguado & Bert, Ch. 1, 2, 3, 4, 5, 6, 9, 10 Location on Earth (L04) Latitude & Longitude great circles, prime meridian, time zones, cardinal points, azimuth

More information

APPI PPG LECTURE 5: FURTHER METEOROLOGY

APPI PPG LECTURE 5: FURTHER METEOROLOGY LECTURE 5: FURTHER METEOROLOGY Introduction: This lecture covers Further Meteorology and aims to give you more of an understanding of advanced weather conditions and patterns. However Meteorology is a

More information

Chapter 2. Turbulence and the Planetary Boundary Layer

Chapter 2. Turbulence and the Planetary Boundary Layer Chapter 2. Turbulence and the Planetary Boundary Layer In the chapter we will first have a qualitative overview of the PBL then learn the concept of Reynolds averaging and derive the Reynolds averaged

More information

Wind Patterns on Earth

Wind Patterns on Earth Wind Patterns on Earth What causes air to move? Air pressure differences causes air to move. These differences in air pressure at the same altitude is caused by uneven heating of the Earth s surface. With

More information

ATMS 310 Tropical Dynamics

ATMS 310 Tropical Dynamics ATMS 310 Tropical Dynamics Introduction Throughout the semester we have focused on mid-latitude dynamics. This is not to say that the dynamics of other parts of the world, such as the tropics, are any

More information

3 Global Winds and Local Winds

3 Global Winds and Local Winds CHAPTER 1 3 Global Winds and Local Winds SECTION The Atmosphere BEFORE YOU READ After you read this section, you should be able to answer these questions: What causes wind? What is the Coriolis effect?

More information

MET 200 Lecture 11 Local Winds. Last Lecture: Forces. Review of Forces. Balance of Forces

MET 200 Lecture 11 Local Winds. Last Lecture: Forces. Review of Forces. Balance of Forces MET 200 Lecture 11 Local Winds Last Lecture: Forces Scales of Motion Eddies Sea Breeze Mountain-Valley Circulations Chinook - Snow Eater Drainage Wind - Katabatic Wind 1 2 Review of Forces 1. Pressure

More information

ANSWERS TO QUESTIONS IN THE NOTES AUTUMN 2018

ANSWERS TO QUESTIONS IN THE NOTES AUTUMN 2018 ANSWERS TO QUESTIONS IN THE NOTES AUTUMN 2018 Section 1.2 Example. The discharge in a channel with bottom width 3 m is 12 m 3 s 1. If Manning s n is 0.013 m -1/3 s and the streamwise slope is 1 in 200,

More information

A majority of these phenomena are mesocale and are induced by stably stratified flow over orography.

A majority of these phenomena are mesocale and are induced by stably stratified flow over orography. Chapter 2. Mountain forced flows 2.1. Mountain waves Well-known weather phenomena directly related to flow over orography include mountain waves lee waves and clouds rotors and rotor clouds severe downslope

More information

CEE 452/652. Week 3, Lecture 1 Mass emission rate, Atmospheric Stability. Dr. Dave DuBois Division of Atmospheric Sciences, Desert Research Institute

CEE 452/652. Week 3, Lecture 1 Mass emission rate, Atmospheric Stability. Dr. Dave DuBois Division of Atmospheric Sciences, Desert Research Institute CEE 452/652 Week 3, Lecture 1 Mass emission rate, Atmospheric Stability Dr. Dave DuBois Division of Atmospheric Sciences, Desert Research Institute Today s topics Review homework Review quiz Mass emission

More information

Small- and large-scale circulation

Small- and large-scale circulation The Earth System - Atmosphere II Small- and large-scale circulation Atmospheric Circulation 1. Global atmospheric circulation can be thought of as a series of deep rivers that encircle the planet. 2. Imbedded

More information

>>>>>>>>WHEN YOU FINISH <<<<<<<< Hand in the answer sheet separately.

>>>>>>>>WHEN YOU FINISH <<<<<<<< Hand in the answer sheet separately. Instructor: Prof. Seiberling PHYSICS DEPARTMENT MET 1010 2nd Midterm Exam October 28, 2002 Name (print, last rst): Signature: On my honor, I have neither given nor received unauthorized aid on this examination.

More information

Goal: Develop quantitative understanding of ENSO genesis, evolution, and impacts

Goal: Develop quantitative understanding of ENSO genesis, evolution, and impacts The Delayed Oscillator Zebiak and Cane (1987) Model Other Theories Theory of ENSO teleconnections Goal: Develop quantitative understanding of ENSO genesis, evolution, and impacts The delayed oscillator

More information

(a) Deflection to the left, slower velocity means greater deflection, greatest deflection at the south pole

(a) Deflection to the left, slower velocity means greater deflection, greatest deflection at the south pole 1 Test 2 Aid Sheet Exam: A single 8.5 by 11 inch aid sheet (both sides) and Type 2 nonprogrammable calculators are permitted. The time allowed for this Test (Part A plus Part B combined) is 90 minutes.

More information

The Physics of Lateral Stability 1

The Physics of Lateral Stability 1 The Physics of Lateral Stability 1 This analysis focuses on the basic physics of lateral stability. We ask Will a boat heeled over return to the vertical? If so, how long will it take? And what is the

More information

Review for the second quarter. Mechanisms for cloud formation

Review for the second quarter. Mechanisms for cloud formation Review for the second quarter Mechanisms for cloud formation 1 Rising air expands and cools; Sinking air compresses and warms. (18) (24) Dry adiabatic lapse rate (10 o C/km): the rate of temperature decrease

More information

PHSC 3033: Meteorology Stability

PHSC 3033: Meteorology Stability PHSC 3033: Meteorology Stability Equilibrium and Stability Equilibrium s 2 States: Stable Unstable Perturbed from its initial state, an object can either tend to return to equilibrium (A. stable) or deviate

More information

3 Global Winds and Local Winds

3 Global Winds and Local Winds CHAPTER 15 3 Global Winds and Local Winds SECTION The Atmosphere BEFORE YOU READ After you read this section, you should be able to answer these questions: What causes wind? What is the Coriolis effect?

More information

The Coriolis force, geostrophy, Rossby waves and the westward intensification

The Coriolis force, geostrophy, Rossby waves and the westward intensification Chapter 3 The Coriolis force, geostrophy, Rossby waves and the westward intensification The oceanic circulation is the result of a certain balance of forces. Geophysical Fluid Dynamics shows that a very

More information

Gravity waves above a convective boundary layer: A comparison between wind-profiler observations and numerical simulations

Gravity waves above a convective boundary layer: A comparison between wind-profiler observations and numerical simulations QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY Q. J. R. Meteorol. Soc. 133: 141 155 (7) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 1.1/qj.7 Gravity waves above a convective

More information

Exploring Wind Energy

Exploring Wind Energy 2013-2014 Exploring Wind Energy Student Guide SECONDARY Introduction to Wind What is Wind? Wind is simply air in motion. It is produced by the uneven heating of the Earth s surface by energy from the sun.

More information

GFD1 AS509/OC512 Winter Q Dargan Frierson Lab 6 P.B.Rhines Kelvin Waves and other inertial/gravity waves Tues 7 Feb 12.30

GFD1 AS509/OC512 Winter Q Dargan Frierson Lab 6 P.B.Rhines Kelvin Waves and other inertial/gravity waves Tues 7 Feb 12.30 GFD1 AS509/OC512 Winter Q. 2017 Dargan Frierson Lab 6 P.B.Rhines Kelvin Waves and other inertial/gravity waves Tues 7 Feb 12.30 With this lab we return to wave propagation; succeeding labs will look at

More information

Prof. Geraint Vaughan. Centre for Atmospheric Science School of Earth, Atmospheric and Environmental Sciences. Bogdan Antonescu

Prof. Geraint Vaughan. Centre for Atmospheric Science School of Earth, Atmospheric and Environmental Sciences. Bogdan Antonescu Upper-level fronts tropopause disturbances and convection Prof. Geraint Vaughan Centre for Atmospheric Science School of Earth, Atmospheric and Environmental Sciences Bogdan Antonescu the meteorological

More information

Lee Waves and Mountain Waves

Lee Waves and Mountain Waves Lee Waves and Mountain Waves Dale R. Durran University of Washington, Seattle, USA December 7, 2013 KEYWORDS: Mountain waves, gravity waves, lee waves Introduction Buoyancy perturbations develop when stably

More information

ENVIRONMENTAL PHYSICS

ENVIRONMENTAL PHYSICS ENVIRONMENTAL PHYSICS Atmospheric Stability An understanding of why and how air moves in the atmosphere is fundamental to the prediction of weather and climate. What happens to air as it moves up and down

More information

Global Winds and Local Winds

Global Winds and Local Winds Global Winds and Local Winds National Science Education Standards ES 1j What is the Coriolis effect? What are the major global wind systems on Earth? What Causes Wind? Wind is moving air caused by differences

More information

Feature Articles. Annyong ha shimnikka

Feature Articles. Annyong ha shimnikka Acoustics Shock Vibration Signal Processing October 2002 Newsletter Annyong ha shimnikka Feature Articles Vibration waves are one of the mechanisms by which nature displays its awesome power. Mountain

More information

Orographic Clouds. "...towering up the darkening mountain's side... It mantles round the mid-way height..."320

Orographic Clouds. ...towering up the darkening mountain's side... It mantles round the mid-way height...320 Chapter 12 Orographic Clouds "...towering up the darkening mountain's side... It mantles round the mid-way height..."320 In previous chapters, we have seen a variety of dynamical features that govern the

More information

An Investigation of February 1999 Chinooks

An Investigation of February 1999 Chinooks An Investigation of February 1999 Chinooks Laura A. Betker Department of Atmospheric and Oceanic Sciences, University of Wisconsin Madison, Undergraduate, Madison, Wisconsin. Abstract: A downslope windstorm

More information

Gravity wave breaking, secondary wave generation, and mixing above deep convection in a three-dimensional cloud model

Gravity wave breaking, secondary wave generation, and mixing above deep convection in a three-dimensional cloud model GEOPHYSICAL RESEARCH LETTERS, VOL. 33,, doi:10.1029/2006gl027988, 2006 Gravity wave breaking, secondary wave generation, and mixing above deep convection in a three-dimensional cloud model Todd P. Lane

More information

Chapter 11 Waves. Waves transport energy without transporting matter. The intensity is the average power per unit area. It is measured in W/m 2.

Chapter 11 Waves. Waves transport energy without transporting matter. The intensity is the average power per unit area. It is measured in W/m 2. Chapter 11 Waves Energy can be transported by particles or waves A wave is characterized as some sort of disturbance that travels away from a source. The key difference between particles and waves is a

More information

Strengthening of the tropopause inversion layer during the 2009 sudden stratospheric warming in the MERRA-2 analysis

Strengthening of the tropopause inversion layer during the 2009 sudden stratospheric warming in the MERRA-2 analysis Strengthening of the tropopause inversion layer during the 009 sudden stratospheric warming in the MERRA- analysis K. Wargan and L. Coy Global Modeling and Assimilation Office Outline We use the MERRA-

More information

Background physics concepts (again)

Background physics concepts (again) Background physics concepts (again) position coordinate for location, say x (1-D) velocity changing position over time (magnitude and ) acceleration changing velocity v = x t = x 2 x 1 t 2 t 1 a = v t

More information

P2.17 OBSERVATIONS OF STRONG MOUNTAIN WAVES IN THE LEE OF THE MEDICINE BOW MOUNTAINS OF SOUTHEAST WYOMING

P2.17 OBSERVATIONS OF STRONG MOUNTAIN WAVES IN THE LEE OF THE MEDICINE BOW MOUNTAINS OF SOUTHEAST WYOMING P2.17 OBSERVATIONS OF STRONG MOUNTAIN WAVES IN THE LEE OF THE MEDICINE BOW MOUNTAINS OF SOUTHEAST WYOMING Larry D. Oolman 1, Jeffrey R. French 1, Samuel Haimov 1, David Leon 1, and Vanda Grubišić 2 1 University

More information

Large-Scale Flow Response to the Breaking of Mountain Gravity Waves François Lott, LMD, Ecole Normale Supérieure;

Large-Scale Flow Response to the Breaking of Mountain Gravity Waves François Lott, LMD, Ecole Normale Supérieure; Large-Scale Flow Response to the Breaking of Mountain Gravity Waves François Lott, LMD, Ecole Normale Supérieure; flott@lmd.ens.fr 1) General: gravity waves and their impact on climate 2) Regional and

More information

ESCONDIDO FIRE DEPT TRAINING MANUAL Section Engine Module Page 1 of 15 Wildland Fire Weather Revised

ESCONDIDO FIRE DEPT TRAINING MANUAL Section Engine Module Page 1 of 15 Wildland Fire Weather Revised Engine Module Page 1 of 15 WEATHER Weather is the most critical element of fire behavior. Weather is also the most unpredictable element. Firefighting personnel should be knowledgeable in local weather

More information

Goals. Unconditional stability Conditional stability Buoyancy Buoyancy waves

Goals. Unconditional stability Conditional stability Buoyancy Buoyancy waves Stability and waves Goals Unconditional stability Conditional stability Buoyancy Buoyancy waves Moist adiabatic lapse rate Archimedes principle A body immersed in a fluid is buoyed up by a force equal

More information

Scott Denning CSU CMMAP 1

Scott Denning CSU CMMAP 1 Thermodynamics, Buoyancy, and Vertical Motion Temperature, Pressure, and Density Buoyancy and Static Stability Adiabatic Lapse Rates Dry and Moist Convective Motions Present Atmospheric Composition What

More information

Simulation and mathematical modeling for racket position and attitude of table tennis

Simulation and mathematical modeling for racket position and attitude of table tennis Acta Technica 62 No. 3A/2017, 135 142 c 2017 Institute of Thermomechanics CAS, v.v.i. Simulation and mathematical modeling for racket position and attitude of table tennis Jiansi Song 1 Abstract. Racket

More information

Wind and Wind Patterns

Wind and Wind Patterns Wind and Wind Patterns What is Weather? Weather is the condition of Earth s atmosphere at a particular time and place. What is Wind? Wind is air moving across the surface of the Earth. It can move horizontally

More information

3 Global Winds and Local Winds

3 Global Winds and Local Winds CHAPTER 6 3 Global Winds and Local Winds SECTION The Atmosphere BEFORE YOU READ After you read this section, you should be able to answer these questions: What causes wind? What is the Coriolis effect?

More information

Waves Part II. non-dispersive (C g =C)

Waves Part II. non-dispersive (C g =C) Waves Part II Previously we discussed Surface Gravity Waves Deep Water Waves Shallow Water Waves C g T 2 C g h dispersive (C g =C/2) Definitions: phase speed C= /T= /k non-dispersive (C g =C) group speed

More information

Tracking of Large-Scale Wave Motions

Tracking of Large-Scale Wave Motions Tracking of Large-Scale Wave Motions Nikki Barbee, Adam Cale, Justin Wittrock Dr. William Gutowski Meteorology 44 Fall 29 This semester we have observed large scale wave patterns in both the Northern and

More information

11. WIND SYSTEMS A&B: Ch 8 (p )

11. WIND SYSTEMS A&B: Ch 8 (p ) 1 11. WIND SYSTEMS A&B: Ch 8 (p 214-238) Concepts: I. Scale II. Differential heating III. Wind direction 1. Scales: Three major divisions Space Time Micro meters seconds - minutes Meso kilometers seconds

More information

A Numerical Study of the Local. Downslope Wind "Yamaji-kaze" in Japan

A Numerical Study of the Local. Downslope Wind Yamaji-kaze in Japan January 1991 K. Saito and M. Ikawa 31 A Numerical Study of the Local Downslope Wind "Yamaji-kaze" in Japan By Kazuo Saito and Motohki Ikawa Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki

More information

Analysis and Research of Mooring System. Jiahui Fan*

Analysis and Research of Mooring System. Jiahui Fan* nd International Conference on Computer Engineering, Information Science & Application Technology (ICCIA 07) Analysis and Research of Mooring System Jiahui Fan* School of environment, North China Electric

More information

Xiaoli Guo Larsén,* Søren Larsen and Andrea N. Hahmann Risø National Laboratory for Sustainable Energy, Roskilde, Denmark

Xiaoli Guo Larsén,* Søren Larsen and Andrea N. Hahmann Risø National Laboratory for Sustainable Energy, Roskilde, Denmark Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 138: 274 279, January 2012 A Notes and Correspondence Origin of the waves in A case-study of mesoscale spectra of wind and

More information

Large-amplitude internal wave generation in the lee of step-shaped topography

Large-amplitude internal wave generation in the lee of step-shaped topography 1 Large-amplitude internal wave generation in the lee of step-shaped topography B. R. Sutherland University of Alberta, Edmonton, Canada. Short title: LARGE-AMPLITUDE INTERNAL WAVE GENERATION... 2 Abstract.

More information

CHAPTER 10: LINEAR KINEMATICS OF HUMAN MOVEMENT

CHAPTER 10: LINEAR KINEMATICS OF HUMAN MOVEMENT CHAPTER 10: LINEAR KINEMATICS OF HUMAN MOVEMENT 1. Vector mechanics apply to which of the following? A. displacement B. velocity C. speed D. both displacement and velocity 2. If velocity is constant, then

More information

P2.20 ANTICIPATING DAMAGING FOEHN WINDSTORMS EAST OF THE CENTRAL APPALACHIANS

P2.20 ANTICIPATING DAMAGING FOEHN WINDSTORMS EAST OF THE CENTRAL APPALACHIANS P2.20 ANTICIPATING DAMAGING FOEHN WINDSTORMS EAST OF THE CENTRAL APPALACHIANS Phillip Manuel* and Stephen Keighton NOAA/National Weather Service, Blacksburg, VA 1. INTRODUCTION Lower tropospheric flow

More information

Atmospheric Circulation

Atmospheric Circulation Atmospheric Circulation Why do we say Earth's temperature is moderate? It may not look like it, but various processes work to moderate Earth's temperature across the latitudes. Atmospheric circulation

More information

= y y. In meteorological parlance, terms such as the above are known as

= y y. In meteorological parlance, terms such as the above are known as Mesoscale Meteorology: The Planetary Boundary Layer 8 March 017 Introduction The planetary boundary layer, sometimes referred to as the atmospheric boundary layer, is a layer of finite depth over which

More information

El Niño Southern Oscillation. Pressure systems over Darwin Australia and Tahiti Oscillate Typically occurs every 4-7 years

El Niño Southern Oscillation. Pressure systems over Darwin Australia and Tahiti Oscillate Typically occurs every 4-7 years El Niño Southern Oscillation Pressure systems over Darwin Australia and Tahiti Oscillate Typically occurs every 4-7 years 1 2 What is it? Normal Conditions... What is it? During El Niño. 3 Local Effects

More information

SIO20 - Midterm Examination 2 v1 Winter Section A. Circle the letter corresponding to the best answer. (1 point each)

SIO20 - Midterm Examination 2 v1 Winter Section A. Circle the letter corresponding to the best answer. (1 point each) NAME: Section A. Circle the letter corresponding to the best answer. (1 point each) 1. Rainbows result from: a. refraction and reflection of sunlight by water droplets b. reflection of sunlight by oceans

More information

9/25/2014. Scales of Atmospheric Motion. Scales of Atmospheric Motion. Chapter 7: Circulation of the Atmosphere

9/25/2014. Scales of Atmospheric Motion. Scales of Atmospheric Motion. Chapter 7: Circulation of the Atmosphere Chapter 7: Circulation of the Atmosphere The Atmosphere: An Introduction to Meteorology, 12 th Lutgens Tarbuck Lectures by: Heather Gallacher, Cleveland State University Scales of Atmospheric Motion Small-

More information

ESCI 485 Air/sea Interaction Lesson 9 Equatorial Adjustment and El Nino Dr. DeCaria

ESCI 485 Air/sea Interaction Lesson 9 Equatorial Adjustment and El Nino Dr. DeCaria ESCI 485 Air/sea Interaction Lesson 9 Equatorial Adjustment and El Nino Dr. DeCaria Reference: El Nino, La Nina, and the Southern Oscillation, Philander THE TWO-LAYER SHALLOW WATER MODEL The ocean can

More information

Practice Questions: Waves (AP Physics 1) Multiple Choice Questions:

Practice Questions: Waves (AP Physics 1) Multiple Choice Questions: Practice Questions: Waves (AP Physics 1) Multiple Choice Questions: 28. A transverse wave is traveling on a string. The graph above shows position as a function of time for a point on the string. If the

More information

Gravity Waves in Shear and

Gravity Waves in Shear and Gravity Waves in Shear and Implications for Organized Convection Sam Stechmann (Wisconsin) and Andy Majda (NYU) (paper in J. Atmos. Sci., 29) Workshop on Modelling Monsoon Intraseasonal Variability Busan,

More information

NATS 101, Section 4, Spring 2009 Midterm Examination #2 March 13, 2009

NATS 101, Section 4, Spring 2009 Midterm Examination #2 March 13, 2009 EXAM NUMBER NATS 101, Section 4, Spring 2009 Midterm Examination #2 March 13, 2009 Name: SID: S Instructions: Write your name and student ID on ALL pages of the exam. In the multiple-choice/fill in the

More information

Title: Gravity wave over flat terrain.

Title: Gravity wave over flat terrain. Title: Gravity wave over flat terrain. Author: Daniel L. Johnson (MD), Mayo Clinic Health System, drdan@wwt.net Abstract: Wave is everywhere throughout the atmosphere, whereever shear exists. Standing

More information

Effects of Moist Froude Number and CAPE on a Conditionally Unstable Flow over a Mesoscale Mountain Ridge

Effects of Moist Froude Number and CAPE on a Conditionally Unstable Flow over a Mesoscale Mountain Ridge FEBRUARY 2005 C H E N A N D L I N 331 Effects of Moist Froude Number and CAPE on a Conditionally Unstable Flow over a Mesoscale Mountain Ridge SHU-HUA CHEN Department of Land, Air, and Water Resources,

More information

SUPERGEN Wind Wind Energy Technology Rogue Waves and their effects on Offshore Wind Foundations

SUPERGEN Wind Wind Energy Technology Rogue Waves and their effects on Offshore Wind Foundations SUPERGEN Wind Wind Energy Technology Rogue Waves and their effects on Offshore Wind Foundations Jamie Luxmoore PhD student, Lancaster University SUPERGEN Wind II - 7 th training seminar 3 rd - 4 th September

More information

Standard atmosphere Typical height (m) Pressure (mb)

Standard atmosphere Typical height (m) Pressure (mb) Standard atmosphere Pressure (mb) Typical height (ft) Typical height (m) 1013.25 0 0 1000 370 110 850 4780 1460 700 9880 3010 500 18280 5570 300 30050 9160 Whiteman 2000 Pressure decreases exponentially

More information

Stormy Weather. tropopause. z i

Stormy Weather. tropopause. z i Stormy Weather tropopause z i z x High Low Stormy Weather Tropopausez Venting by thunderstorms y Venting by fronts x Stormy Weather Height, z tropopause clouds clouds z i BL n cold air warm air z i BL

More information

Chapter 16. Waves-I Types of Waves

Chapter 16. Waves-I Types of Waves Chapter 16 Waves-I 16.2 Types of Waves 1. Mechanical waves. These waves have two central features: They are governed by Newton s laws, and they can exist only within a material medium, such as water, air,

More information

Earth s Atmosphere. Earth s atmosphere is a key factor in allowing life to survive here.

Earth s Atmosphere. Earth s atmosphere is a key factor in allowing life to survive here. Chapter 10.2 Earth s Atmosphere Earth s atmosphere is a key factor in allowing life to survive here. This narrow band of air has the right ingredients and maintains the correct temperature, to allow life

More information

REMINDERS: Problem Set 2: Due Monday (Feb 3)

REMINDERS: Problem Set 2: Due Monday (Feb 3) REMINDERS: Problem Set 2: Due Monday (Feb 3) Midterm 1: Next Wednesday, Feb 5 - Lecture material covering chapters 1-5 - Multiple Choice, Short Answers, Definitions - Practice midterm will be on course

More information

V. SEA and LAND BREEZES:

V. SEA and LAND BREEZES: V. SEA and LAND BREEZES: A. Pressure largely reflects the weight of overlying air, owing to gravity, and is proportional to mass. Therefore pressure decreases with height. 1. Remember, surface pressure

More information

MAR 555 Lecture 20: Coastal Tides

MAR 555 Lecture 20: Coastal Tides MAR 555 Lecture 20: Coastal Tides Tides caused by the resulting gravitational and centrifugal forces is called equilibrium tide. They can be expressed using the harmonic functions as N semi! e(semi) =

More information

Static Fluids. **All simulations and videos required for this package can be found on my website, here:

Static Fluids. **All simulations and videos required for this package can be found on my website, here: DP Physics HL Static Fluids **All simulations and videos required for this package can be found on my website, here: http://ismackinsey.weebly.com/fluids-hl.html Fluids are substances that can flow, so

More information

An Undular Bore and Gravity Waves Illustrated by Dramatic Time-Lapse Photography

An Undular Bore and Gravity Waves Illustrated by Dramatic Time-Lapse Photography AUGUST 2010 C O L E M A N E T A L. 1355 An Undular Bore and Gravity Waves Illustrated by Dramatic Time-Lapse Photography TIMOTHY A. COLEMAN AND KEVIN R. KNUPP Department of Atmospheric Science, University

More information

Global Structure of Brunt Vaisala Frequency as revealed by COSMIC GPS Radio Occultation

Global Structure of Brunt Vaisala Frequency as revealed by COSMIC GPS Radio Occultation ICGPSRO, May 14-16, 2013, Taiwan Session 3A; U3-2B-208-05 14:10-14:25, May 14 Global Structure of Brunt Vaisala Frequency as revealed by COSMIC GPS Radio Occultation Noersomadi National Institute of Aeronautics

More information

Sediment transport. Sediment transport. Boundary layer stress. τ : This lecture

Sediment transport. Sediment transport. Boundary layer stress. τ : This lecture Sediment transport GEO3-4306: oastal Morphodynamics Sediment transport This lecture background modes of sediment transport cross-shore transport longshore transport sediment balance oundary layer stress

More information