NATS 101-05

Lecture 12
Curved Flow and Friction
Local winds

Supplemental References for TodayÕs Lecture


	Gedzelman, S. D., 1980: The Science and Wonders of the Atmosphere. 535 pp. John-Wiley & Sons. (ISBN 0-471-02972-6)
	Danielson, E. W., J. Levin and E. Abrams, 1998: Meteorology. 462 pp. McGraw-Hill. (ISBN 0-697-21711-6)

Recall: Uniform Circular Motion Requires Acceleration/Force

Flow Around Curved Contours

Forces for Curved Flow

Gradient Wind Balance

Divergence and Convergence

Vertical Motion

Slide 11

Slide 12

Slide 13

Slide 14

Now
Add Friction near the surfaceÉ

This changes the force balance

Force of Friction 1

Force of Friction 2

Force of Friction 3

Force of Friction 4

Force of Friction 5

Flow at Surface Lows and Highs

Slide 22

Friction Induced Vertical Motion

Summary


	Curved Flow
	Requires Centripetal Acceleration
	Difference between PGF and Coriolis Force
	Speed Changes => Convergence-Divergence
	Frictional Force
	Causes Winds to Turn toward Low Pressure Important in the lowest 1 km above the Surface Leads to Convergence-Divergence
	Curvature and Friction
	Leads to Vertical Motions

Atmospheric Scales of Motion

Review:
Thermally Direct Circulation

Sea Breeze Development
(Courtesy of Mohan Ramamurthy, WW2010)

Sea Breeze versus Land Breeze (Courtesy of Mohan Ramamurthy, WW2010)


	Stronger Temperature contrast during PM than during AM
	Sea breezes are stronger than land breezes

Sea Breeze


	Regular feature of many coastal areas
	California, Florida, Gulf Coast
	Occurs along large lakes-Great Lakes
	Typically strongest during Spring-Summer
	Can penetrate inland 50 km or more
	Temperatures can drop ~10^oC
	Nose of cool air can trigger thunderstorms
	Florida Satellite Loop

Mountain-Valley Breeze

Phoenix-Tucson Diurnal Winds

Assignment for Next Lecture