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Mountain Weather and Climate

Mountain Weather and Climate. Meteorology 3000 490 INSCC MWF 9:40-10:30 John Horel. Photo: J. Horel. Course Objective. Understand the influence of the earth’s orography upon weather and climate

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Mountain Weather and Climate

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  1. Mountain Weather and Climate Meteorology 3000 490 INSCC MWF 9:40-10:30 John Horel Photo: J. Horel

  2. Course Objective • Understand the influence of the earth’s orography upon weather and climate • Apply understanding of mountain weather and climate to human activities (safety, health, sport, fire, road) Photo: J. Horel

  3. Course Outline • 1. Overview. Mountain Climates • 2: Vertical structure; stability. Thermals and Personal Flying Craft • 3: Boundary layer and surface energy budget. The VTMX and Peter Sinks Experiments. • 4: Pressure, Winds. Large-scale Mountain Effects. • 5: Fronts. Evolution of Intermountain Storms. • 6: Clouds. Understanding Weather Changes by Watching Clouds. • 7: Precipitation. Orographic storms and Great Salt Lake effect snowstorms.

  4. Course Outline (cont.) • 8: Terrain-forced flows. Utah Canyon Wind storms. • 9: Diurnal Mountain Winds. Local drainage circulations. • 10: Air Pollution. Air Quality in the Salt Lake Basin. • 11: Fire Weather. • 12: Physiological Effects of High Altitude. • 13: Snowpack. Physics of skiing • 14: Avalanches. • 15: Mountain Road Weather. • 16: Review

  5. Grading • 45%: Homework and assignments, class participation, • 30%: 3 quizzes • 25%: final

  6. Reading Assignments • Roughly 1 chapter per week (1 article per week in the later weeks) • It is required that you finish the reading assignment PRIOR to the lectures and in-class assignments on the reading material • Be prepared to discuss material in reading assignment

  7. Homework Assignment #0 • Bring in a couple (to as many as you want) of mountain and mountain weather related photos OR even better, send them to me as email • 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, I will scan the images and return them to you • Write your name on the back of each photo • Due: Any time during the semester. Can be done multiple times for extra credit

  8. Field Day • First choice- Saturday October 12 • Second choice- Saturday October 19 • Weather permitting • Monitor atmospheric conditions at Snowbird • Requires planning in advance by class to design useful field project • Requires analysis of data after data collection completed Photo: J. Horel

  9. Mountains …lofty mountains are most worthy of deep study. For everywhere you turn, they present to every sense a multitude of objects to excite and delight the mind. They offer problems to our intellect; they amaze our souls. They remind us of the infinite variety of creation, and offer an unequaled field for the observation of the processes of nature. Josias Simler, 1574: De alpibus commentarius Mountains complement desert as desert complements city, as wilderness complements and completes civilization. Edward Abbey

  10. What is a mountain? • Subjective • Roderick Peattie Mountain Geography (1936)- Mountains are 1) impressive, 2) enter into the imagination of people living in their shadow, and 3) have individuality. • Objective definition should include: • Elevation (insufficient criterion, e.g., Great Plains) • Local relief (Grand Canyon?, incised into plateau) • Steepness of slope • The amount of land in slopes Whiteman

  11. What is a mountain? • Common usage: • 600 m or more of local relief defines a mountain • Less than 600m is a hill • High mountain/alpine areas (Troll 1973; Arct. Alp. Res., 5, 19-27): • Relative to terrain features • Upper timberline • Snow line Himalayas: Photo credit: NASA/Science Photo Library

  12. If the earth were greatly reduced in size while maintaining its shape, it would be smoother than a billiard ball. (Earth radius = 6371 km; Everest = 8.850 km) • Nonetheless, mountains have a large effect on weather. Why is this, if they are so insignificant in size? • Answer: the atmosphere, like the mountains, is also shallow (scale height 8.5 km) so mountains are a significant fraction of atmosphere’s depth. • But, this answer underestimates mountain effect for two reasons: • Stability gives the atmosphere a resistance to vertical displacements • The lower atmosphere is rich in water vapor so that slight adiabatic ascent brings the air to saturation. • Example: flow around a 500-m mountain (<< 8.5 km) could include 1) broad horizontal excursions, 2) downslope windstorm on lee side, and 3) torrential orographic rain on windward side. (Smith, 1979)

  13. 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)

  14. Effects of Mountains Carruthers and Hunt 1990

  15. Distribution of mountains on the globe http://www.peakware.com/encyclopedia/

  16. Mountains • % mountains as fraction of total land surface • 0-1000 m 10% • 1000-2000 m 3% • 2000-3000 m 3% • > 3000 m 4% • Total 20% Barry 1992 Photo: J. Horel

  17. Highest 10 mountains in the world Mountain peak Range Location Height (m) Everest Himalayas Nepal/Tibet 8,850 K2 Karakoram Pakistan/China 8,611 Kanchenjunga Himalayas India/Nepal 8,586 Lhotse I Himalayas Nepal/Tibet 8,516 Makalu I Himalayas Nepal/Tibet 8,463 Cho Oyu Himalayas Nepal/Tibet 8,201 Dhaulagiri Himalayas Nepal 8,167 Manaslu I Himalayas Nepal 8,163 Nanga Parbat Himalayas Pakistan 8,125 Annapurna Himalayas Nepal 8,091

  18. The Himalayas

  19. Mt. Everest • http://www.mteverest.com/ • http://www.mnteverest.net/ • http://www.m.chiba-u.ac.jp/class/respir/eve_e.htmhttp://www.newton.mec.edu/Angier/DimSum/Him.Range%20Pix.html • Height of Mt. Everest: 8848m (http://www.m.chiba-u.ac.jp/class/respir/hyoko_e.htm)

  20. Mountains McKinley Denali Mt. Kenya Kilimanjaro Matterhorn http://www.peakware.com/encyclopedia/ Makalu Fitzroy Credits: McKinley: Corel Corporation Kilimanjaro: Bo Flemstrong Mt. Kenya: Rudolf Willing Cerro Fitzroy: Frank Sauer Matterhorn: Tony Simpkins Makalu: Catholic Uni Mtn Club of Santiago de Chile Whiteman

  21. Highest Peaks By Continent

  22. Alps Tinguely

  23. Mountains in North America Whiteman (2000)

  24. U.S. Peaks http://www.peakware.com/encylopedia

  25. Appalachian Mountains Whiteman (2000)

  26. Mountains of the western US Whiteman (2000)

  27. High Elevation Observatories • Mt Washington • http://www.mountwashington.org/ • Storm Peak Laboratory • http://www.dri.edu/Projects/SPL/

  28. Utah http://go-utah.com/utah-mountains-lakes.cfm

  29. Homework Assignment #1 • (1) Find 3 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 paragraph description of the content of each page • (3) Provide at least 2 scientific, literary, or artistic (music/art) definitions of a mountain. Not from dictionaries • (4) Provide a reference/source for that definition and send it in the same email as that used above • Due August 28

  30. Avalanche that destroyed Alta Utah in Cottonwood Canyon Thomas Moran, 1895 Marriott Library Archive

  31. Mt. Denali Tornado. Picutre by ?. Provided by J. Yount

  32. Existence on a mountain is simple. Seldom in life does it come any simpler: survival, plus striving toward the summit. The goal is solidly three-dimensionally there- you can see it, touch it, stand upon it – the way to reach it well defined, the energy of all directed toward its achievement. It is this simplicity that strips the veneer of civilization and makes that which is meaningful easier to come by – the pleasure of deep companionship, moments of uninhibited humor, the tasting of hardship, sorrow, beauty, joy. But it is this very simplicity that may prevent finding answers to the questions I have asked as we approached the mountains.” ~ Tom Hornbein, Everest: The West Ridge Source: Willis, C. (ed.), 1997. Epic: Stories of Survival from the World’s Highest Peak; pg. 220.

  33. Lenticular clouds. Mt. Washington. Jay Shafer

  34. The Storm Testament (Ch 21, 2nd paragraph)        Beaver George and I were riding up a little valley, scattered ponderosa pine on either side and willows, alder and aspen in the bottom where the small stream wound its way from beaver pond to beaver pond. It was a winding valley, and we couldn't see very far ahead. It was early afternoon; the deep blue of the Rocky Mountain Shy made a sharp contrast to the scattered puffy white clouds. The sun was warm, but not uncomfortable, thanks to a fresh breeze coming gently down from the mountains ahead of us.

  35. Rime. Mt. Washington. Jay Shafer

  36. My father considered a walk among the mountains as the equivalent of churchgoing. - Aldous Huxley

  37. Mt. Rainier. Ken Hart

  38. "Enjoy the mountains; they have beauty and wisdom for us if we approach them with humility, respect, and knowledge." -Charles Houston

  39. Mt. Everest. Summer 2001. W. Ozanne

  40. Mountains and uplands may defined as features of the Earth's surface in which the terrain projects conspicuously above its surroundings, and where the slope of the land distinguishes it from the generally flat plains."Beniston, Martin. Environmental Change in Mountains and Uplands.  New York: Oxford University Press, 2000, p. 1.

  41. "Enjoy the mountains; they have beauty and wisdom for us if we approach them with humility, respect, and knowledge." -Charles Houston, Ansel Adams. Haldane Gas? Brad Navarro

  42. "Gradually, very gradually, we saw the great mountains sides and glaciers and aretes, now one fragment and now another through the floating rifts,until far higher in the sky than imagination had dared to suggest the white summit of Everest appeared." George Mallory, 1921.-"Lost on Everest: The Search for Mallory & Irvine".  Firstbrook, Peter.1999.  page 45. Mt. Everest. Summer 2001. Bill Ozanne

  43. Four main climate factors Whiteman(2000) Climate differs from one location to another because of: • Latitude • Altitude • Continentality • Exposure to regional circulations, including winds and ocean currents

  44. Latitude • Determines length of day and angle of incoming sunlight and, thus, amount of solar radiation received • In equatorial regions, day length & solar angle change little with season. Little seasonal variability, mostly diurnal changes. • In polar regions, the sun does not rise at all in winter. In the summer it never sets, although remaining low in sky. Big seasonal changes, small diurnal changes. • In mid-latitudes, seasonal and diurnal changes. • Also determines site’s exposure to latitudinal belts of high and low pressure • High pressure - subsidence • Low pressure - convection Whiteman

  45. Altitude • Solar radiation increases with altitude • Changes in air temperature at high altitudes are small, however, because of smaller amount of land area at higher altitudes • Air temperature usually decreases with altitude (-6.5°C/km) • Moisture in air usually decreases with altitude • Wind speed usually increases with altitude • Air density and atmospheric pressure decrease exponentially with altitude Whiteman

  46. Continentality • Continental locations experience larger diurnal and seasonal temperature changes than locations on or near large bodies of water because land surfaces heat and cool more quickly than oceans. • Interior locations experience more sunshine, less cloudiness, less moisture and less precipitation than coastal areas. • Precipitation is especially heavy on the windward side of coastal mountain ranges oriented perpendicular to prevailing winds from the ocean. Marine air lifted up a mountain range releases much of its moisture as precipitation. As a result, far less precipitation is received on the leeward side. Whiteman

  47. Regional circulations • Latitude, altitude and continentality are the primary factors, but exposure to regional winds and ocean currents is also a factor • Some regional winds are associated with the latitudinal bands of high and low pressure (e.g., Pacific High, Aleutian low, Bermuda-Azores high) • Ocean currents also play an important role. Ex: Gulf Stream in Atlantic and Japanese Current in Pacific affect North America. Whiteman

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