Download - Mountain Meteorology
Mountain Meteorology
Meteorology 5550
490 INSCC
TH 10:45 – 12:05
John Horel
Jim Steenburgh Photo: J. Horel
Mountains complement desert as desert complements city, as wilderness complements and completes civilization. Edward Abbey
Course Objectives and Content
Understand the influence of the earth’s orography upon weather and climate
First Half- John Horel Geographical controls of
mountain weather and climate Terrain-forced flows Flow interaction with complex
terrain
Photo: J. Horel
Course Content (cont.) Second half- Jim Steenburgh
Orographically modified cyclones Orographically trapped disturbances Orographic precipitation
Invited presentations Fire weather Air quality Avalanches Surface transportation
Houze 1993
Grading
40%: Homework, class participation, literature reviews
20%: Participation and writeup of results from field experiment
20%: 1st half quiz 20% 2nd half quiz
Source Material
Mountain Meteorology. D. Whiteman. 2000. Mountain Weather and Climate. R Barry. 1992. Atmospheric Processes over Complex Terrain. W.
Blumen 1990. Influence of Mountains on the Atmosphere. R.
Smith. 1979. Advances in Geophysics. 21. Additional Reading
Reading Assignments
Many available on-line. To save trees, you are to access them on-line from campus and print them as needed
http://ams.allenpress.com/amsonline/?request=index-html
First Reading Assignment First reading assignment: Barry, R. G. (1978): H. B. de
Saussure: the first mountain meteorologist. Bull. Amer. Meteor. Soc., 59, 702-5.
Summarize in a few paragraphs: (1) who Saussure was; (2) how did he make the measurements and what were his results regarding the decrease of temperature with height; (3) what other contributions to mountain meteorology did he make?
Due: via email at beginning of class on Aug. 30. Send to [email protected], Be prepared to discuss the reading during that class.
Field Project Analysis of wind circulations on ski-
jump slope Weather permitting
Set up on Friday September 28 Observations Saturday morning September
29 Takedown in afternoon
Requires planning in advance by class to design useful field project
Requires analysis of data after data collection completed
Photo: J. Horel
VTMX Workshop
September 10-12 Useful presentations on local wind circulations in
Salt Lake Valley Plan on attending a few hours at some point
instead of class on the 11th (and 13th?)
What is a mountain? Common usage:
600 m or more of local relief defines a mountainLess than 600m is a hill
High mountain/alpine areas (Troll 1973; Arct. Alp. Res., 5, 19-27):Relative to terrain featuresUpper timberlineSnow line
Himalayas: Photo credit: NASA/Science Photo Library
What are the effects of mountains? Substantial modification of synoptic or meso scale
weather systems by dynamical and thermodynamical processes through a considerable depth of the atmosphere
Recurrent generation of distinctive wx conditions, involving dynamically and thermally induced wind systems, cloudiness, and precipitation regimes
Slope and aspect variations on scales of 10-100 m form mosaic of local climates
(Barry 1992)
Effects of Mountains
Carruthers and Hunt 1990
Whiteman (2000)http://infoplease.lycos.com/ipa/A0001792.html
Precipitation
Barry 1992
Barry (1992)
Mountains % mountains as fraction of total land surface (land 30%) 0-1000 m 10% 1000-2000 m 3% 2000-3000 m 3% > 3000 m 4% Total 20%
Barry 1992 %mountain as fraction of earth 6%
Mt. Everest http://www.mteverest.com/ http://www.mnteverest.net/ http://www.m.chiba-u.ac.jp/class/respir/eve_e.htm http://www.newton.mec.edu/Angier/DimSum/
Him.Range Pix.html Height of Mt. Everest: 8848m(http://www.m.chiba-u.ac.jp/class/respir/hyoko_e.htm)
High Elevation Observatories Mt Washington
http://www.mountwashington.org/
Storm Peak Laboratoryhttp://www.dri.edu/Projects/SPL/
Geographical controls of mountain climate (Barry 1992)
Latitude Continentality Altitude Topography
Jeff Klein. SLC BLM)Jeff Klein. SLC BLM)
Thermally forced terrain circulations
Mountain-valley winds Slope flows Peter Sinks Experiment VTMX lake breeze
Flow Interaction With Complex Terrain
Photo: J. Horel
Buoyancy oscillations Flow over vs. around
obstacles Kinetic and potential energy
of flows Mountain waves Gravity wave drag Trapped lee waves
Downslope Windstorms
Conceptual models Observations Numerical studies Gap winds
L. Darby & R. Banta, ATDD/ETL
Other subjects
Orography and the General Circulation Mountain torque
Physiology of high altitude Climate change at high altitude
1st Homework Assignment Bring in a couple (to as many as you want) of
mountain and mountain weather related photos Be prepared to say a few words about 1-2 photos If you’re willing to allow use of the photos for this
class and future classes, scan the images on the PC in Rm 480 (details to be provided, but don’t leave them with me)
Due: whenever
Homework Assignment #2 (1) Find 5 interesting and useful internet web pages related to
mountain weather, mountain climates, or alpine environments (2) Send me in 1 email the web addresses with a 1-2 sentence
description of the content of each page (3) Provide at least 2 scientific, literary, or artistic (music/art)
definitions or descriptions of mountains. Not from dictionaries (4) Provide a reference/source for that definition and send it in
the same email as that used above Due August 30
Parameters used to define flow (Smith 1979)Parameter Symbol Units Typical Value
Mountain height h km 1
Width downstream Lx km 10
Width crossstream Ly km 100
Flow layer depth H km 1 PBL; 10 troposphere
Incoming windspeed u m/s 10
Incoming wind shear uz s-1 10-3
Stability frequency N s-1 10-2
Coriolis parameter f s-1 10-4
Buoyancy/reduced gravity
b = g m/s2 10-1