chapter 9: air and chapter 10: extratropical cyclones (quiz 4) Flashcards

Question

Upper-Level Front - do air masses extend to the surface of the Earth? - air masses can be ___ in the vertical, so that an air mass front can be present aloft ---> this type of front is call ____ or _____ - Upper-level fronts are a common feature within what? - How do upper-level fronts develop?

Answer 1

* Air masses do not necessary extend to the surface of the Earth. * Air masses can be “stacked” in the vertical, so that an air mass boundary (i.e., front) can be present aloft. * This type of front is called “cold front aloft” or “upper-level front”. * Upper-level fronts are common feature within cyclones that form east of the Rockies. *Upper-level fronts develop when the air from the west of the trough (which goes through adiabatically descending) meets the air from the east of the trough (which goes through moist adiabatically ascending)

Answer 2

- Dynamic Effects- How upper level winds cause low pressure systems - Thermodynamic Effects- How heating and cooling cause regional highs and lows. - Friction Effects- How friction with Earth’s surface cause convergence and divergence at the surface

Answer 3

Combined curvature and jetstreak effects produce upper-level convergence on the west side of the trough to the north of the jetsreak, which add air mass into the vertical air column and tend to produce a surface high- pressure center. The same combined effects produce a upper-level divergence on the east side of the trough and favors the formation of a low-level low-pressure center

Answer 4

JET STREAM WAVES (ROSSBY WAVES) ARE CRUCIAL TO THE FORMATION OF LOW PRESSURE SYSTEMS THAT CREATE STORM FRONTS

Answer 5

heating surface --> low pressure cooling surface --> high pressure

Answer 6

Surface friction will cause convergence into the surface low- pressure center after it is produced by upper-level dynamic effects, which adds air mass into the low center to “fill” and weaken the low center (increase the pressure)

Answer 7

The evolution of a low center depends on the relative strengths of the upper- level divergence and low-level friction damping

Answer 8

The development of a high center is controlled more by the convergence of surface cooling than by the upper-level

Answer 9

* Fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth. * On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east). * Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet.

Answer 10

* If two air masses of different temperatures or densities meet, the resulting pressure difference caused by the density difference (which ultimately causes wind) is highest within the transition zone. * Pressure differences and Coriolis Effect create the jet stream

Answer 11

In general, two Jet Streams in each Hemisphere at boundary between main circulation cells

Answer 12

*Waves in the Jet Stream are called Rossby Waves. *Rossby Waves drive weather patterns at the surface *Located near the tropopause at a pressure level of about 250mb (recall that surface pressure is approx. 1,000 mb)

Answer 13

- Atmospheric boundary that demarcates the troposphere from the stratosphere; - Five layers of the atmosphere 1. troposphere 2. stratosphere 3. mesophere 4. thermosphere 5. exosphere

Answer 14

Giant meanders in Jetstream that have a major influence on weather at mid-latitudes.

Answer 15

*The first indications of this phenomenon came from American professor Elias Loomis in the 1800s, when he proposed a powerful air current in the upper air blowing west to east across the United States as an explanation for the behavior of major storms. *After the 1883 eruption of the Krakatoa volcano, weather watchers tracked and mapped the effects on the sky over several years. They labelled the phenomenon the "equatorial smoke stream"

Answer 16

He tracked pilot balloons, also known as pibals (balloons used to determine upper level winds),as they rose into the atmosphere. Oishi's work largely went unnoticed outside Japan because it was published in Esperanto

Answer 17

*Esperanto was created in the late 1870s and early 1880sby L. L. Zamenhof, a Polish-Jewish ophthalmologist fromBiałystok, then part of the Russian Empire, but now partof Poland. *In the 1870s, just a few years before Zamenhof createdEsperanto, Polish was banned in public places in Białystok. *According to Zamenhof, he created the language to: - reduce the "time and labor we spend in learning foreign tongues", - to foster harmony between people from different countries *"Were there but an international language, all translations would be made into it alone ... and all nations would be united in a common brotherhood.“ *Esperanto didn’t catch on, so Oishi’s ideas about the jet stream were not recognized.

Answer 18

- Real understanding of the nature of jet streams due to regular and repeated flight-path traversals during World War II. - Flyers consistently noticed westerly tailwinds in excess of 160 km/h (100 mph) in flights, for example, from the US to the UK

Answer 19

*An incendiary balloon weapon deployed by Japan against the United States during World War II. *A hydrogen balloon measuring 10 metres (33 ft) in diameter, it carried a payload of two 11-pound (5.0 kg) incendiary devices plus one 33-pound (15 kg) anti-personnel bomb (or alternatively one 26-pound (12 kg) incendiary bomb). * It made use of the jet stream, and was intended to start large forest fires. *Between November 1944 and April 1945, the Japanese launched about 9,300 balloons from sites on Honshu, of which about 300 were found or observed in the U.S., with some in Canada and Mexico.

Answer 20

- Despite the high hopes of designers, who created a sophisticated ballast system to control altitude on the three-day flight, the balloon bombs were largely ineffective due to damp forest conditions and malfunctions, causing only six deaths (from a single civilian incident in Oregon) and minor damage. - On May 5, 1945, six civilians were killed near Bly, Oregon, when they discovered one of the balloon bombs in Fremont National Forest, becoming the only fatalities from enemy action in the continental U.S. during the war. - The Fu-Go balloon was the first weapon to possess intercontinental range - Constructed from five thin layers of a durable paper derived from the paper mulberry (kōzo) bush, which were glued together with konnyaku (Japanese potato) paste. - The Japanese Army mobilized thousands of teenage girls at high schools across the country to laminate and glue the sheets together, with final assembly and inflation tests at large indoor arenas

Answer 21

Extratropical cyclone – a storm system that forms along the jetstream between about 30 and 70 degrees latitude  These storms are also called mid-latitude cyclones

Answer 22

Nature’s way of balancing the temperature differences between the poles and equator (in the horizontal) and between the upper and lower troposphere (in the vertical) in the mid- latitudes....Hadley and Polar Cells transport much of the heat at low and high latitudes

Answer 23

is a visual pattern of clouds resembling a comma, often associated with mature extratropical cyclones, and can be seen in satellite imagery.

Answer 24

Characteristics of extratropical cyclones:  Sea level pressure ---> Low pressure center  Airflow at the surface ---> Cyclonic, or counterclockwise, in northern hemisphere  Size and appearance --->Several 100 to several 1000 miles across (~1/3 lower 48 states)  Cyclone life cycle ---> Several days to over a week

Answer 25

1. East of Colorado Rockies (flatter part of Colorado but high elevation) 2 .East of Canadian Rockies 3. TX-LA coastline (Gulf of Mexico, warm water fuels storms) 4. Along US east coast 5. Over Bering Sea and Gulf of Alaska in northern Pacific Ocean (important in bringing moisture to western US)

Answer 26

* The Great Red Spot is an anticyclone, a long-lasting area of high pressure on Jupiter creating a persistent storm. * Located in Jupiter's Southern Hemisphere, it is the largest storm in our solar system, appearing as a giant red spot on Jupiter's surface. It has existed for the last 150 years, possibly even longer according to NASA.

Answer 27

* Rain patterns that control agriculture production * Responsible for much of the severe weather in US: - Tornadoes - Lightning - Hail - Straight-line winds - Supercell thunderstorms - Heavy rain/flooding - Blizzards

Answer 28

- surface air masses - upper level air masses

Answer 29

The region of a jet stream axis with the greatest winds

Answer 30

Extratropical cyclones, or mid-latitude cyclones, initially develop as disturbances along frontal zones (boundaries between air masses of different temperatures), often near a jet stream maximum, where divergence aloft leads to surface pressure falls

Answer 31

- Low pressure at the surface in an extratropical cyclone forms when warm air rises due to the interaction of fronts, causing air to move upward and decrease pressure at the surface, leading to the development of a low-pressure system; this process is often associated with the convergence of cool and warm air masses along a front - At upper levels, extratropical cyclone formation is associated with a region of upper-level divergence above a developing low-pressure center, which helps pull air upwards and sustains the surface cyclone's development - Wave: a ripple in the jetstream

Answer 32

In response to a cyclone, surface air masses move towards the low-pressure center in a spiraling, counterclockwise pattern in the Northern Hemisphere (clockwise in the Southern Hemisphere), converging and rising to form the storm's core

Answer 33

At the upper levels of the troposphere, you'll find a mix of air masses, including those that are cold and dry, like continental polar (cP) air, and moist and warm air masses, like maritime tropical (mT) air

Answer 34

Mid-latitude cyclones are associated with cold and warm fronts, with the cold front typically extending to the south and west, and the warm front to the east of the low-pressure center

Answer 35

1. warm front 2. the clouds and precipitation associated with a warm front are located ahead of the surface position of the front 3. As you move north of a warm front, clouds tend to become lower and thicker, transitioning from high, wispy cirrus clouds to lower, widespread stratus and nimbostratus clouds, often leading to steady, light to moderate precipitation

Answer 36

1. South of a cyclone center in the Northern Hemisphere, you'll typically find a warm, moist air mass, often referred to as maritime tropical (mT) air 2. South of a cyclone center in the Northern Hemisphere, you typically find a cold front and a warm front - The position and types of fronts south of the cyclone center may be different from one cyclone

Answer 37

1. Upslope flow – air is forced to rise as it flows from lower elevations to higher elevations 2. As air rises, it expands and cools adiabatically, this cooling leads to condensation and cloud formation. 3. showers and thunderstorms 4. Alberta clipper – an extratropical cyclone that is similar to extratropical cyclones that form east of the Colorado Rocky Mountains, but that forms east of the Rocky Mountains in Alberta, Canada

Answer 38

D. Towards the east, south

Answer 39

A. east, west - starting in south, warm air moves into cold air - cold air starts in canada and starts wrapping arouns

Answer 40

B. Ahead of the warm front

Answer 41

- if jet stream is going slower and is weaker and probably moving north, initiation of the storm will be less common - initiation of storms less common - frequency depends on how the waves of the jet stream moves across

Answer 42

* Surface warm dry air: cT * Surface warm moist air: mT * Descending dry upper air coming over Rockies: cT

Answer 43

 A cyclone is said to intensify when the pressure at the surface decreases.  Pressure gradient force? - Increases  Wind speed? - Increases  Movement of air masses - Temperature and moisture gradients along fronts become tighter = heavier precipitation and possibility for severe weather

Answer 44

* Divergence aloft intensifies storm * Convergence at surface weakens storm - Race between divergence aloft and convergence near the surface

Answer 45

* Divergence aloft is initially due to Jetstream curvature and jet streaks. * Convergence at surface is due to friction.

Answer 46

Air spirals inward towards a low-pressure center as it slows due to friction because the reduced wind speed weakens the Coriolis force

Answer 47

1. Start with idealized low with gradient wind. (circular wind pattern around low pressure center) 2. Add surface friction in planetary boundary layer: * Boundary layer- region of the lower troposphere where the surface strongly influences temperature, moisture, and wind through the turbulent transfer of air mass as a result of surface friction 3. In boundary layer- wind slows down 4. Slower wind leads to smaller Coriolis Force 5. PGF becomes bigger than Coriolis Force 6. Air flow responds to force imbalance and flowing towards low pressure center (convergence).

Answer 48

* Thus, for intensification there must be a process or feedback that strengthens the curvature of the Jetstream trough and the strength of the jet streak. * A FEEDBACK based on the relationship of temperature and air volume makes this happen

Answer 49

- Remember that the low-pressure center is to the northeast of the trough axis. - As cold air advances south, on the west side of the low center, the height of upper level constant pressure surfaces will decrease, causing the upper level trough to deepen - As warm air advances north, on the east side of the low pressure center, the height of the upper level constant pressure surfaces will increase, causing the upper level ridge to amplify.

Answer 50

 As cold air advances south, on the west side of the low pressure center, the height of upper level constant pressure surfaces will decrease, causing the upper level trough to deepen.  As warm air advances north, on the east side of the low pressure center, the height of the upper level constant pressure surfaces will increase, causing the upper level ridge to amplify.  Both the deepening trough and the amplifying ridge lead to: - Increased curvature between the trough and the ridge - Increased wind speed in the jetstreak  How do these upper level changes impact the surface cyclone? - Lower surface pressure = intensification!

Answer 51

1. Jet stream divergence initiates storms. 2. The poles are warming 4 times faster than the mid-latitudes and tropics. 3. Strength of the Jetstream depends on the difference in temperature between lower latitude and polar air masses. 4. For every degree increase the atmosphere holds about 7% more water vapor. 5. Gulf of Mexico is warming.