| NATS 101 Lecture 18 Local Winds |
| Supplemental References for TodayÕs Lecture |
| Danielson, E. W., J. Levin and E. Abrams, 1998: Meteorology. 462 pp. McGraw-Hill. (ISBN 0-697-21711-6) |
| Review: Forces for Curved Flow |
| Slide 4 |
| Divergence and Convergence |
| Slide 6 |
| Slide 7 |
| Vertical Motion |
| Review: Friction |
| Flow at Surface Lows and Highs |
| Slide 11 |
| Friction Induced Vertical Motion |
| Atmospheric Scales of Motion |
| Review: Thermally Direct Circulation |
| Sea Breeze Development (Courtesy of Mohan Ramamurthy, WW2010) |
| 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 ~10oC | |
| Nose of cool air can trigger thunderstorms | |
| Florida Satellite Loop |
| Mountain-Valley Breeze |
| Phoenix-Tucson Diurnal Winds |
| Darwin was Right |
| The Darwin "Natural Selection" Awards are given each year to bestow upon (the remains of) that individual, who through single-minded self-sacrifice, has done the most to remove undesirable elements from the human gene pool. | |
| www.darwinawards.com | |
| Darwin was Right |
| Ladies and Gentlemen...(drum roll...and envelope please)... | |
| We proudly present: Larry Walters, who now (hopefully) realizes the value of knowing some basic meteorology. |
| Darwin was Right |
| Larry Walters is among the relatively few who have actually turned their dreams into reality. | |
| His story is true (confirmed), though you may find it hard to believe. | |
| Darwin was Right |
| Larry was a truck driver, but his lifelong dream was to fly. | |
| When he graduated from high school, he joined the Air Force in hopes of becoming a pilot. | |
| Unfortunately, poor eyesight disqualified him. |
| Darwin was Right |
| So when he finally left the service, he had to satisfy himself with watching others fly the fighter jets that crisscrossed the skies over his backyard. | |
| As he sat there in his lawn chair, he dreamed about the magic of flying. |
| Darwin was Right |
| Then one day, Larry Walters got an idea. | |
| He went down to the local army-navy surplus store and bought a tank of helium and forty-five weather balloons. |
| Darwin was Right |
| These were not your brightly colored party favors, these puppies measured 4 feet across and held 33 cubic feet of helium. | |
| Back in his yard, Larry used straps to attach the balloons to his lawn chair, the kind of chair you have in your own yard. |
| Darwin was Right |
| He anchored the chair to the bumper of his jeep and inflated 42 of the balloons with helium. | |
| Then he packed some sandwiches, beers and loaded a BB gun, figuring that he could pop a few balloons when it was time to return to earth. |
| Darwin was Right |
| Preparations complete, Larry Walters sat in his chair and cut the anchoring cord. | |
| His plan was to float slowly upward a few hundred feet, pop a few balloons, and lazily float back down to terra firma. | |
| But things didn't quite work out that way. |
| Darwin was Right |
| When Larry cut the cord, he didn't float lazily up; he bolted up as if fired from a cannon! | |
| Nor did he go up a couple hundred feet. | |
| He climbed and climbed and climbed until he finally leveled off at 16,000 feet! |
| Darwin was Right |
| At that height, he feared deflating any of the balloons, lest he unbalance the load and really experience flying! | |
| So he stayed up there, drifting cold and frightened for 14 hours, totally at a loss as to how to get down. |
| Darwin was Right |
| Eventually, Larry drifted into the approach corridor for Los Angeles International Airport. | |
| A Pan Am pilot radioed the tower about passing a guy in a lawn chair at 16,000 thousand feet with a gun in his lap. (FolksÉthat's a conversation I'd have given anything to have heard!) |
| Darwin was Right |
| LAX is right on the ocean, and yÕall know at nightfall or aloft during the day, the winds along the coast blow offshore. | |
| As dusk fell, Larry (alledgedly) even drifted out over the ocean for awhile. |
| Darwin was Right |
| Larry eventually gathered enough nerve to shoot a few balloons and slowly descended. | |
| But as Larry approached the ground, he got entangled in power lines that caused a blackout in Long Beach. | |
| Once on terra firma, he was arrested. |
| Darwin was Right |
| But as he was being led away in handcuffs, a television reported called out, "Mr. Walters, why'd you do it?" | |
| Larry stopped, eyed the man, then replied nonchalantly, "A man can't just sit around." |
| Darwin was Right (Most of the Time!) |
| Congratulations Larry, you are a rare survivor to earn (honorable mention) for the prestigious | |
| Darwin ÒNatural SelectionÓ Award | |
| So, whatÕs the moral of the story? | |
| If you donÕt learn basic meteorology, then you too will be strategically positioned to receive the | |
| Darwin "National Selection" Award |
| Summary |
| Land-Sea Breeze | |
| Due to differential heating between land-sea | |
| Gives diurnal reversal in temperature contrast | |
| Onshore winds PM - Offshore winds AM Sea Breeze PM - Land Breeze AM | |
| Mountain-Valley Breeze | |
| Differential heating along mountain slopes Gives diurnal reversal in temperature contrast Upslope winds PM - Downslope winds AM Valley Breeze PM - Mountain Breeze AM |
| Next Lecture |
| Monsoon Circulations-Seasonal Winds | |
| Asia Monsoon | |
| ÒArizonaÓ Monsoon | |
| Assignment for Next Lecture |
| Reading – Ahrens pg 173-175 | |
| Problems - 7.5 |