Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
104 Cards in this Set
- Front
- Back
|
What determines the relative strength of winds?
|
The change in atmospheric pressure over the surface. Air flows from high pressure to low pressure. The more rapid the change (the steeper the pressure gradient), the faster the winds; the more gradual the change (the flatter the pressure gradient), the slower the winds.
|
|
|
How do meteorologists depict this on maps?
|
With isolines called isobars, mapping points of equal pressure as lines
|
|
|
Why is the Coriolis Effect best described as an “optical illusion”?
|
It is the apparent deflection of motion toward or away from the Equator away from a straight path. Actually, the motion is in a straight line, but the Earth rotates beneath the motion, creating the illusion of deflected motion.
|
|
|
Why is the predominant wind pattern in the mid-latitudes west to east?
|
Air flows from the tropics into the mid-latitudes; this is motion away from the low latitudes, so the motion is deflected by the Coriolis effect from west to east.
|
|
|
Why is air mostly rising at the Equator and mostly descending in the Tropics?
|
The Equator is in the direct path of the Sun’s rays throughout the year, so it is constantly warmed by solar radiation. This creates rising air, which cools with elevation and sinks back to the surface in the tropics.
|
|
|
What are jet streams
|
High altitude winds that are not slowed by surface friction
|
|
|
What influence do they have on weather in the mid-latitudes?
|
The polar jet can bring cold air from the high latitudes into the mid-latitudes and the tropical jet can bring warm air from the low latitudes into the mid-latitudes
|
|
|
What is El Niño?
|
El Niño is a weather anomaly, a change from the expected conditions on the western, coastal region of South America. Usually this is a desert with very little precipitation. The Atacama Desert is mostly caused by tropical high pressure and a cold current along the shore, coming up from Antarctica. During El Niño years, ocean circulation along the Equator reverses, from “east to west” to “west to east.” This sends warm water along the western side of South America, suppressing the cold current. El Niño years bring heavy storms off the ocean, causing flooding and mud slides in Peru and northern Chile.
|
|
|
What are the three ways that meteorologists describe humidity
|
Absolute humidity: percent of air that is water vapor; specific humidity: mass of water vapor per mass of air; relative humidity: water vapor in air, relative to maximum water vapor air could hold at current temperature
|
|
|
What is an adiabatic temperature change
|
The change in the temperature of a gas by expanding (cooling) or compressing (warming) it.
|
|
|
What is the environmental lapse rate?
|
The temperature decrease with increasing elevation in the troposphere.
|
|
|
If surface air is rising and cooling until it reaches saturation, why is Earth not completely covered with clouds, with constant precipitation?
|
Most rising air becomes stable because the general atmosphere is not cooling as fast as the air rising from the surface.
|
|
|
What is forced lifting?
|
Stable air is “physically” lifted to the appropriate elevation to reach saturation
|
|
|
How does it explain how most clouds form?
|
either by being blown up an elevated surface, by a wedging of cold air underneath warm air, or by surface air converging and lifting stable air.
|
|
|
Why do most clouds not cause precipitation?
|
They are too high and too insubstantial (thin, icy) for water droplets or ice crystals falling from them to reach the ground.
|
|
|
How do radiation fogs and advection fogs differ from evaporation fogs?
|
Radiation fogs and advection fogs form from the contact of warm air with a cool surface, while evaporation fogs form from the contact of cool air with a warm surface.
|
|
|
Why do high clouds (cirrus-form) not cause precipitation?
|
They are too high and too thin, being mostly ice crystals.
|
|
|
How do low clouds and vertically developed clouds differ?
|
Low clouds (stratus-form) form near the surface, mostly from forced lifting. They are flat and layered in appearance and produce steady but light precipitation that may last several days. Vertically developed clouds (cumulus-form clouds) begin forming near the surface and rise to great heights within the troposphere. They are columnar in shape and can cause thunderstorms, tornadoes, and hailstorms.
|
|
|
What is the Bergeron Process and how does it differ from Collision-Coalescence
|
The Bergeron Process describes how snow forms. It is only possible where the tops of clouds are cold enough for ice to form. Collision-Coalescence is possible where the tops of clouds are warm enough for water droplets to accumulate enough mass to survive falling to the ground as rain.
|
|
|
What is acid deposition
|
It is the acidification of precipitation and particles with sulfur and nitrogen oxides.
|
|
|
What causes acid deposition?
|
Burning coal to make electricity and the heat of exhaust from fossil fuel burning
|
|
|
What are some results of acid deposition?
|
Deforestation, soil depletion, acidification and contamination with heavy metals in ponds and lakes, fish kills, groundwater contamination.
|
|
|
If oxides of sulfur and nitrogen form naturally, why is there a concern with acid deposition?
|
Human activities (burning fossil fuels) have increased the levels of oxides of sulfur and nitrogen three times over natural levels. Also, human production of these oxides is concentrated in relatively small areas, while natural sources are diffused over a larger area, lessening the impact.
|
|
|
Which air masses have the greatest influence on the weather of North America, especially east of the Rocky Mountains?
|
Maritime Polar
|
|
|
cA Continental Arctic
|
very cold, dry; Arctic basin to Greenland, stable
|
|
|
cP Continental Polar
|
cold, dry; interior Canada and Alaska, stable
|
|
|
cT Continental Tropical
|
hot, dry; northern Mexico, southwest U.S., unstable
|
|
|
mT Maritime Tropical
|
warm, wet; Gulf of Mexico, Caribbean, western Atlantic, unstable ; subtropical Pacific, stable entire year;
|
|
|
mP Maritime Polar
|
cool, moist; north Pacific, unstable in winter, stable in summer; northwest Atlantic, unstable in winter, stable in summer
|
|
|
What are some possible causes of thunderstorms?
|
(1) orographic lifting on mountain slopes; (2) frontal lifting at cold fronts, sometimes warm fronts; (3) convergence at the surface can lift stable air and cause a thunderstorm. A hurricane is in effect a wall of thunderstorms in constant development.
|
|
|
Describe the development of a thunderstorm
|
Due to convection, or convergence, or the orographic effect, or a cold front, cumulus clouds begin to form. In the “cumulus” stage of the thunderstorm, air flow is up into the cloud (updraft). Rain is light, and may not have begun yet. If the cumulus cloud continues to grow in height and size, it becomes a cumulonimbus cloud. This is the “mature” stage of the thunderstorm. Most of the rain, lightning, thunder (and possibly tornadoes and/or hailstones) will occur in the mature stage. Ice and water droplets will begin to form and fall through the cloud, creating a downdraft on one side of the cloud. There is still an updraft into the cloud, but the downdraft ultimately cools the cloud. When the air flow is strictly out of the cloud, because of the downdraft, the cloud is at the “dissipating” stage and the cloud loses organization and the storm ends.
|
|
|
What are lightning and thunder?
|
Lightning is the release of static electricity from the cloud to the ground, or the ground to the cloud, or from cloud to cloud, or within the cloud itself. Thunder is the result of the rapid heating and cooling of air molecules as the charge passes through them, causing them to “pop”. The rumble is due to the sound moving down or up the column of air molecules.
|
|
|
How does a cold front differ from a warm front?
|
At a cold front, cold air is wedging beneath slower moving warm air, lifting the warm air and creating a steep boundary between the air masses. This favors the formation of cumulonimbus clouds and thunderstorms. At a warm front, warm air is riding up over slower moving cold air, cooling and forming clouds in the process. The warm front has a flatter frontal boundary than the cold front, produces flat, layered nimbostratus clouds and more gradual precipitation for a longer period.
|
|
|
What are the three main forms of cyclonic precipitation?
|
Mid-latitude cyclone (extratropical cyclone); hurricane (tropical cyclone, typhoon, baguio); tornado
|
|
|
How do they differ?
|
They differ in how they form, where they form, when they form, how long they last, why they end, their frequency of formation, their size, internal pressure gradient, wind speeds they produce.
|
|
|
What do they have in common?
|
They have in common that they are rising columns of air that spiral inward.
|
|
|
Explain why mid-latitude cyclones have both a cold front and a warm front in progress simultaneously.
|
The mid-latitude cyclone begins as a stationary front with zonal flow along the frontal boundary. If the opportunity exists for air to flow across this frontal boundary in either direction, it sets off the cyclonic spin. Cold air is directed down into the cyclone, creating a cold front, while warm air is directed up into the cyclone, creating a warm front.
|
|
|
What causes the middle latitude cyclone to end?
|
Since the cold front is moving faster than the warm front, the cold front overtakes the warm front and they combine their air masses along an occluded front. The occluded front closes off the rising warm air sector from the surface. This cuts off the source of energy for the storm and it loses organization.
|
|
|
26. In the northern hemisphere, the “east” side of the hurricane is considered to be more dangerous when it comes on shore first, while the “west” side of the hurricane is considered to be less dangerous when it comes on shore. Why?
|
The air flow at the surface on the east (right) side of the hurricane is toward the land surface, pushing up water and wind directly to the land, while the west (left) side is blowing away from the land surface. Either side of the hurricane causes a storm surge (the rise in water as the storm comes on shore), however.
|
|
|
What factors favor the formation of tornadoes?
|
A strong contrast between air masses along a cold front, strong convective currents, the formation of a mesocyclone within a thunderstorm.
|
|
|
What are some possible causes for the formation of hurricanes?
|
the movement of a low pressure cell from a tropical land service into the tropical ocean; (2) convergence and lifting of the Intertropical Convergence Zone as it moves into the “summer” hemisphere; (3) the entry into tropical waters of a trough of low pressure from the mid-latitudes; (4) easterly waves traveling in the path of the trade winds developing a cyclonic air flow.
|
|
|
What is an easterly wave?
|
: It is an east to west flow of air over tropical waters, with the flow converging (north) into the easterly wave, and diverging (south) out of the easterly wave. A tropical disturbance may form on the eastern side of the wave, although this usually does not happen.
|
|
|
How do hurricanes end?
|
Hurricanes end when they: pass over land, move into colder water, pass under high pressure or a temperature inversion.
|
|
|
Why do hurricanes generally not form along the Equator?
|
Along the Equator, the Coriolis Effect is too weak to initiate the spin.
|
|
|
Why are hurricanes infrequent in the South Atlantic and the Southeastern Pacific?
|
In the South Atlantic and the Southeastern Pacific, the water is too cool to cause the strong convective motion to initiate hurricane formation.
|
|
|
What are the components of the Saffir-Simpson Scale?
|
The Saffir-Simpson scale describes hurricanes based on: central barometric pressure; sustained wind speeds in walls of hurricane; storm surge created by winds; and potential damage.
|
|
|
What is the storm surge?
|
It is the rise in sea level as the hurricane comes on shore. If this occurs during high tide, the rise is the combination of the two
|
|
|
What factors can make it worse?
|
Storms in the northern hemisphere are stronger on the “right” or east side, if this is the side that comes on shore, the wind damage and storm surge will also be worse.
|
|
|
The Koppen Climate Classification System is based on what five factors?
|
Temperature, precipitation, timing and amount of precipitation, relative severity of winter, geographic position.
|
|
|
What is the purpose of a climograph?
|
It provides enough information to determine the climate type for a given location. A climograph shows monthly average temperature with a line graph, with the scale on the left of the graph.
|
|
|
What information does a climograph present?
|
It shows monthly precipitation with a bar graph, with the scale on the right of the graph. It shows the latitude and longitude for the location, its total yearly precipitation, and its average annual range of temperature.
|
|
|
Both desert and steppe are Dry Climates. How do they differ from each other?
|
In a desert climate, every year ends with a moisture deficit (evapotranspiration is greater than precipitation).In a steppe climate, most years end with a small moisture surplus (evapotranspiration is less than precipitation).
|
|
|
Why do climates become progressively drier with distance from the Equator, and then become relatively wet again when the mid latitudes are reached?
|
At the equator is persistent low pressure, in the tropics is persistent high pressure, in the mid latitudes, air mass conflict and cooler temperatures favor frontal precipitation.
|
|
|
Why are the tropical steppe so barren and the midlatitude steppe so fertile?
|
Cooler temperatures in the mid latitude steppe better preserve the low precipitation.
|
|
|
What are the predominant influences on tropical deserts and midlatitude deserts?
|
The main reason for the formation of the tropical is persistent high pressure, preventing air from rising and forming clouds. In the mid latitude desert the main reason for dryness in continentality, preventing moisture bearing winds from reaching the interior of continents. For both kinds of deserts the blocking effect of mountain barriers also causes dryness.
|
|
|
Why is the Marine West Coast climate so wet and the Humid Continental so dry?
|
Marine West Coast climates are on the windward side of their continents and benefit from warm currents alongside the continent. Humid Continental climates are cool but relatively dry because they form in the interior and on the downwind side of their continents.
|
|
|
Why is the Mediterranean climate so dry and the Humid Subtropical relatively wet?
|
: The Mediterranean climate forms in coastal areas on the western side of the continents in the lower mid latitudes, where tropical high pressure expands during the long summer. This prevents precipitation until the pressure retreats during the cool months. On the opposite, eastern, side of the continent at these latitudes, frontal precipitation, monsoons, and tropical cyclones all contribute to higher levels of precipitation than on the western side of the continent.
|
|
|
Describe the influence of elevation on climate
|
Thinner air, cooler temperatures, often wetter conditions.
|
|
|
Where is the Earth’s water located, as percentages of the total?
|
97.2% of Earth's water is too mineralized to drink; 2% of Earth’s total water is fresh water in glacial ice on Greenland and Antarctica; .5% of the Earth’s total water is groundwater under the continents; remaining .25% of Earth’s total water is in lakes, soil moisture, streams, atmospheric water, and biological water.
|
|
|
What are the basic characteristics of the world’s four oceans? Is there a “Southern” ocean?
|
Pacific: 46% of Ocean Water; 33% of Surface; Atlantic: 23% of Ocean Water; 16% of Surface; Indian: 20% of Ocean Water; 14% of Surface; Arctic: 4% of Ocean Water; 3% of Surface. The Southern Ocean would be the very cold waters around Antarctica. It would be defined by the transition to the warm waters of other oceans, not by land barriers like the other four oceans.
|
|
|
What is the average salinity of seawater?
|
Ocean salinity averages 3.5%,
|
|
|
Why does salinity vary in the oceans?
|
freshest water in open ocean is along Equator; saltiest water in open ocean is along the Tropics; bays, gulfs, inlets can be saltier or fresher than the open ocean.
|
|
|
Describe the causes of tides in the world’s oceans
|
Gravitational pull of the Moon 56% and the Sun 44%
|
|
|
What are “Spring” tides and “Neap” tides?
|
During the Spring Tides, the Sun and the Moon are either lined up “behind” the Earth or they are on opposite sides of the Earth - in either case, their mutual gravitational pull is accentuated. This corresponds to the full moon and the dark of the moon. The Neap Tides corresponds to the waxing half moon and the waning half moon, when the Sun and the Moon are at right angles to each other, relative to the Earth
|
|
|
What causes them?
|
This reduces their mutual “pull” on the Earth. Spring tides correspond to both the highest high tide and the lowest low tide. The Neap tides represent the least difference between high tide and low tide. Every 28 days there are two Spring tides and two Neap tides - these dates move across the Solar year’s months, however.
|
|
|
Why would lakes be “fresh” or “saline”?
|
Fresh water lakes have both an inflow and an outflow of water from streams and/or springs; if a lake does not have a significant outflow, the lake becomes highly mineralized (salty).
|
|
|
Where are the Earth’s largest lakes located? Why?
|
Lakes need both a source of water and a containing geologic structure. The biggest lakes are either pluvial (due to the last ice age) or formed by major tectonic activity. The Great Lakes of North America formed after the last Ice Age (about 18 to 20 thousand years ago); the Great Lakes of East Africa are part of the Great Rift Valley. The largest lake in the world is the Caspian Sea, due to its region of interior drainage and a significant inflow of water from its primary source, the Volga River.
|
|
|
What basic physical qualities does a material need to be an aquifer?
|
Porosity (pore space where water can be stored) and permeability (ability to transmit water)
|
|
|
What are some reasons why groundwater is best considered a non-renewable resource?
|
Subsidence: water table drops, may result in collapse of surface into sinkhole; salinization: coastal aquifers may be contaminated by seawater because of overuse; pollution: septic tanks, sewer lines, industry; fossil aquifer, not being replenished by current precipitation (the Ogalalla Aquifer is a fossil aquifer that formed at the end of the last ice age).
|
|
|
altitudinal zonation
|
vertical pattern of temperature and climate
|
|
|
anthropogenic
|
caused by humans
|
|
|
Bergeron process
|
how snow forms
|
|
|
chinook
|
“snow-eater” winds, caused by the warming of air descending downslope
|
|
|
cirrus
|
thin, wispy clouds that form very high and generally do not cause precipitation
|
|
|
collision/coalescence
|
how rain forms when cloud tops are too warm for freezing nuclei to form ice crystals
|
|
|
Coriolis effect
|
the apparent deflection of motion toward or away from the Equator
|
|
|
cumulus
|
vertically developed clouds that may produce thunderstorms
|
|
|
dew point
|
the temperature at which the air is saturated and condensation will begin
|
|
|
dry summer subtropical
|
a mid-latitude climate found on the western side of its continent, a distinct summer drought followed by a mild winter with some precipitation
|
|
|
easterlies
|
the predominant surface air flow from the poles to the mid-latitudes
|
|
|
environmental lapse rate
|
the temperature decrease with elevation in the troposphere
|
|
|
evapotranspiration
|
the combined moisture loss to the air from the soil and plant surfaces
|
|
|
fossil aquifer
|
an underground water resource that formed at the end of the last Ice Age and that is not being maintained by current precipitation
|
|
|
frontal wedging
|
cold air forces itself under warm air, lifting the warm air and causing clouds to form
|
|
|
humid continental
|
on the downwind side of a mid-latitude land mass, absent in the Southern Hemisphere, long, cold winter, short growing season, some potential for row crops, tree crops, and dairying
|
|
|
humid subtropical
|
a mild, mid-latitude climate with a long, hot, wet summer and a relatively short and wet winter, found on the eastern side of its continent
|
|
|
hydrologic cycle
|
the transition of water molecules between various physical forms over time
|
|
|
icecap
|
temperatures are always colder than freezing, no vegetation other than lichen
|
|
|
insolation
|
the amount of solar radiation available at the surface
|
|
|
jet stream
|
high altitude winds that follows relatively predictable paths, in excess of 50 miles per hour
|
|
|
katabatic
|
gravitational wind, caused by the heaviness of very cold air sinking downslope
|
|
|
land breeze
|
a nighttime flow of air from the land to the ocean
|
|
|
monsoon
|
a seasonal reversal of wind direction, causing a wet season and a dry season
|
|
|
orographic effect
|
forced lifting of stable air up a sloped surface, like a mountain
|
|
|
pluvial
|
a lake that formed at the end of the last Ice Age
|
|
|
relative humidity
|
the actual water vapor in the air, relative to the water vapor the air could hold, at some temperature
|
|
|
sea breeze
|
a daytime flow of air from the ocean to the land
|
|
|
stratus
|
layered, low clouds, often associated with warm fronts
|
|
|
vertically developed clouds
|
another name for cumulus-form clouds
|
|
|
westerlies
|
the predominant wind flow from the Tropics to the Mid-latitudes, west to east
|
|
|
trades
|
the predominant wind flow from the Tropics to the Equator, east to west
|
|
|
subarctic
|
long, very cold winters, brief mild summers, little potential for agriculture other than herding, originally covered with extensive coniferous forests
|
|
|
tropical wet and dry
|
a very wet climate of the low latitudes with a short, but distinct dry season
|
|
|
tundra
|
experiences some period with temperatures warmer than freezing, otherwise, year-round cold temperatures, sparse, low-growing vegetation
|
