Name: ___________________________________________
Treasure Hunt#4
Mountain Meteorology
Due: Wed. 2 April 2014
Terrain-Forced Flows, MetEd Articles#2-3
Score:____________/ 20
(1) What two types of waves are collectively called orographic waves in the textbook and which type are
often confined or trapped in the lee of mountain barriers by smooth, horizontal flow above {found on
page(s)__________}.
(2) Barrier jets always turn to the ________ in the Northern Hemisphere as they approach a mountain
barrier {fill in the blank, found on page(s)__________ of the textbook}.
(3) Gap winds in coastal regions in the wintertime often flow from the pool of cold air located over the
________ (continent or ocean, choose one). Briefly explain why gap winds blow in this preferred direction
{found on page(s)__________ of the textbook}.
(4) List two contributions other than advection that can cool air within a cold air wedge, thereby making
the cold air dam more stable {found on page(s)__________ of the textbook}.
(5) Name the nocturnal weather feature with maximum speeds often in excess of 35 mph only 800 – 1500
ft above the ground, which slopes downward from the foothills of the Rocky Mountains to the Mississippi
River {found on page(s)__________ of the textbook}.
(6) What three characteristics of the atmosphere determine how it responds to the presence of mountains
{found in MetEd module#2}?
(7) In order for an object to go over a mountain, its ________ energy must be greater than its ________
energy {fill in the blanks}. What atmospheric properties are related to the gravitational potential energy
and kinetic energy {found in MetEd module#2}?
(8) Related to atmospheric stability and wind speed, what combination of these two properties makes
blocked flow more likely {found in MetEd module#2}?
(9) Briefly explain what causes air to go out of geostrophic balance as it flows near the mountains, from
the east {found in MetEd module#2}.
(10) If you released a weather balloon through blocked flow and all data was lost except for the wind
direction and altitude, how could you tell the depth of the blocked flow from the wind direction data
{found in MetEd module#2}? Be more specific than “the direction would change.”
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(11) A mountain wave is stationary. Such a wave is referred to as a ________ wave. {fill in the blank}
{found in MetEd module#3}.
(12) Name two societal impacts associated with mountain waves {found in MetEd module#3}.
(13) For a vertically-propagating mountain wave having sufficient amplitude, an aircraft flying overhead
may experience clear air turbulence over what range in altitude {found in MetEd module#3}?
(14) Describe the difference between the current and historical explanations of Foehn warming {found in
MetEd module#3}.
(15) For the Rocky Mountains and a standard U.S. atmosphere [lapse rate = 6.5oC/km], approximately
what wind speed is required for a Froude number of 1? What is the significance of a Froude number of 1
related to mountain wave activity {found in MetEd module#3}?
(16) How is a critical level identified in a weather balloon sounding and what role does the critical level
play in enhancing a leeside downslope windstorm {found in MetEd module#3}?
(17) Aside from a critical level, what other atmospheric structure may also impede the vertical propagation
of energy and contribute to the acceleration of downslope winds? What is the optimal altitude for this
feature in order to maximize its contribution to the acceleration of downslope winds{found in MetEd
module#3}?
(18) In Case 1 of the downslope winds exercise, what type of mountain wave resulted in an environment
having forward wind shear between 2 and 8 kilometers? How does the Froude number change with height
in the environment having forward shear {found in MetEd module#3}?
(19) In the Salt Lake City windstorm of April 1999, name the relevant vertical temperature and wind
features, along with their elevations, that combined to make this a significant event {found in MetEd
module#3}.
(20) Name the “1.6 rule” related to trapped lee waves {found in MetEd module#3}.
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