Final Exam Flashcards
Atmosphere
– invisible envelope of gasses
and particles that surrounds the earth.
Meteorological hazards
associated with
Weather – instantaneous state of the atm
(hours-days).
Hydrological hazards
occur in response to
weather, specifically precipitation.
Climate
long term avg condition and
range of atm characteristics.
Climatological hazards
associated with
persistent weather patterns, characteristic
of a region’s climate.
Insolation
incoming solar radiation
Thermal radiation
wavelengths of
energy sensed/measured as heat
Counter-radiation
heat absorbed by
GHG and reradiated back to surface
Evaporation
- phase change of liquid
water to vapor - Transfers water to atmosphere where
clouds can form
Latent Heat
If the water vapor absorbs enough energy, they will begin to vibrate fast enough to break their molecular bonds and become individual water molecules or gas.
Conduction
is the transfer of heat from a warmer object to a cooler object through molecule interaction. As the Sun heats the ground, energy is transferred to the atmosphere by conduction.
Heat vulnerability
is one of the most significant public health risks
posed by climate change
Latitude
because of the Earth’s shape the angle of the Sun hitting the planet, temperatures are greatest near the equator and decrease toward the poles.
Distribution of land and water on the planet.
Places near the ocean tend to have milder climates year-round versus regions surrounded by land. This is because the earth can heat up and cool down faster and greater than the ocean.
The Hydrologic Cycle/Water Cycle
- Water moves between earth’s surface and atmosphere through phase changes. Is the system that creates the hydrosphere.
- There are six storage areas of water on Earth: the atmosphere, oceans, bodies of fresh water, plants and animals, groundwater, and glaciers.
- large quantities of heat are transferred horizontally, called advection or wind, in the form of latent heat
Humidity
is defined as the amount of water vapor in the atmosphere.
Relative humidity
is the ratio of the atmosphere’s actual water vapor content compared to the amount of water vapor required for atmospheric saturation at that temperature and is usually expressed as a percentage
Precipitation – Rain, snow, sleet, hail, Freezing rain
Convection
is the transfer of heat by the mass movement of a fluid (such as water and air).
Global Atmospheric Circulation
Heat and moisture are distributed globally by movement in the atmosphere. Through convection and advection (Wind)
Advection/Wind
In the process of evaporation, large quantities of heat are transferred horizontally, in the form of latent heat
Atmospheric Pressure
force
exerted on earth’s surface by the
atmosphere
Anticyclones:
- Sinking air
- High pressure
- Dry air
- Clear skies
Anticyclones/High Pressure
occurs when descending air molecules “pile up” at the surface and spread outward in a clockwise rotation in the Northern Hemisphere (counterclockwise in the Southern Hemisphere). Descending air warms, which prevents water vapor to condense into clouds to produce storms. Instead, regions under high pressure tend to experience clear skies.
Cyclones/Low pressure
occurs when converging air is forced upward (in a counterclockwise manner in the Northern Hemisphere) where it cools and condenses into clouds and possible storms. Ultimately, air flows from high pressure to low pressure and this is called wind.
Cyclones
Rising air
* Low pressure
* Clouds &
precipitation
Air mass
Large body of air w/
homogenous T & Td (moisture)
characteristics
Air mass Weather
Weather
patterns dominated by air masses. Persistent, anticyclonic weather patterns.
Cold air masses
high latitudes over
cold surfaces.
Warm air masses
low latitudes over
warm surfaces.
Blocking High’s
A strong high pressure system that settles in and refuses to budge.
Cold waves
have become less frequent across the nation
Heat waves
heat waves have become more frequent and intense, is a period of unusually hot weather that typically lasts two or more days. To be considered a heat wave, the temperatures have to be outside the historical averages for a given area.
Drought
- as a “period of unusually persistent dry weather that persists long enough to cause serious problems such as crop damage and/or water supply shortages. The severity of the drought depends upon the degree of moisture deficiency, the duration, and the size and location of the affected area.
- is one of the greatest natural hazards globally.
- Dryness and Desertification which is the permanent degradation of arable (agriculturally usable) land into deserts.
Wind chill
combined affects of cold temp & wind speed
Heat index
combined effects of heat
& humidity
Mid-latitude cyclones
are
cyclones formed by
convergence of tropical (warm)
& polar (cold) air along the jet
stream.
Cyclones
travel along the jet
stream following predictable
paths called storm tracks.
Storms tracks
predictable paths of the storms
Midlatitude cyclones may produce
- Heavy snow
- Bands of freezing rain
- Flooding rain
- Severe thunderstorms
Fronts
is a transition zone between two air masses of different densities, temperatures and/or moisture. When two air masses come into contact with each other, they do not like to mix well because of their different densities - much like water and oil.
Cold Front
are zones separating two distinct air masses, of which the cooler, denser mass is advancing and replacing the warmer. The colder, more dense air pushes under the warm air forcing the warm, lighter air upward. If the warm air rising is unstable enough, large thunderstorms are likely to occur.
Warm front
marks the boundary between a warm air mass that is replacing a cooler air mass. When a warm air mass advances over a cold air mass, the warm air rises over, but at a more gentler rate than a cold front
Warm sectors
the boundary of the advancing warm subtropical air is a warm front.
Cold sectors
The advancing boundary of the cold polar air is a cold front
Pressure
is a force created by the weight of the atmosphere. Because of gravity, air pressure is greatest at sea level and decreases with height
Snow
precipitation that forms in wintertime clouds starts out as snow because the top layer of the storm is usually cold enough to create snowflakes. Snowflakes are just collections of ice crystals that cling to each other as they fall toward the ground. Precipitation continues to fall as snow when the temperature remains at or below 0 degrees Celsius from the cloud base to the ground.
Sleet
occurs when snowflakes only partially melt when they fall through a shallow layer of warm air. These slushy drops refreeze as they next fall through a deep layer of freezing air above the surface, and eventually reach the ground as frozen rain drops that bounce on impact.
Freezing Rain
occurs when snowflakes descend into a warmer layer of air and melt completely. When these liquid water drops fall through another thin layer of freezing air just above the surface, they don’t have enough time to refreeze before reaching the ground. Because they are “supercooled,” they instantly refreeze upon contact with anything that that is at or below 0 degrees C, creating a glaze of ice on the ground, trees, power lines, or other objects.
Rain
is liquid water falling from nimbostratus or cumulonimbus clouds. Many times in the mid-latitudes, precipitation will fall from clouds in the form of snow which melts on its way down toward the ground.
Downbursts and Microbursts.
Sometimes the moisture within downdrafts falling from the thunderstorm evaporates as it enters dryer air below the cloud. As the moisture evaporates, the air cools because of latent heat, causing the air to become denser. This in turn causes the air to fall faster. As this denser air hits the ground, it spreads out laterally producing cold winds reaching 100 miles per hour. Microbursts can uproot trees, damage property, and are very dangerous for airplanes taking off or landing.
Tornadoes
A tornado is a narrow, violently rotating column of air that extends from a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. Tornadoes can be among the most violent phenomena of all atmospheric storms we experience.
Nor’easters
is a strong low-pressure system that affects the Mid-Atlantic and New England states. It can form over the land of the eastern U.S. or over the Atlantic coastal waters. These winter events are notorious for producing heavy snow, rain, and tremendous waves that crash onto Atlantic beaches, often causing beach erosion and structural damage.
Alberta Clippers
a fast-moving low-pressure system that originates in or near the Canadian province of Alberta just east of the Rocky Mountains and tracks east-southeastward across southern Canada and the northern United States to the North Atlantic Ocean
Blizzards
Are dangerous winter storms that are a combination of blowing snow and wind resulting in very low visibilities. While heavy snowfalls and severe cold often accompany blizzards, they are not required. Sometimes strong winds pick up snow that has already fallen, creating a ground blizzard.
Ice storm
is a storm which results in the accumulation of at least .25” of ice on exposed surfaces. They create hazardous driving and walking conditions. Tree branches and powerlines can easily snap under the weight of the ice.
Lightning
lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges build up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again.
Thunderstorms
A thunderstorm is a rain shower during which you hear thunder. Since thunder comes from lightning, all thunderstorms have lightning.
TS Stage: Cumulus
, where an air parcel is forced to rise, cool, and condense, called the lower condensation level, to develop into a cumulus cloud. The process of water vapor condensing into liquid water releases large quantities of latent heat, which makes the air within the cloud warmer, and unstable causing the cloud continues to grow upward like a hot air balloon. These rising air parcels, called updrafts, prevent precipitation from falling from the cloud.
TS stage: mature stage
mature stage. During this stage, updrafts and downdrafts exist side-by-side and the cumulonimbus is called a cell. If the updrafts reach the top of the troposphere, the cumulus cloud will begin to spread outward creating a defined anvil. At the same time, the downdrafts spread within the cloud and at first make the cloud become wider, but eventually overtaking the updrafts. Cool downdrafts form when precipitation and the cool air from entrainment are dragged down to the lower regions of a thunderstorm.
TS stage: Dissipating
During this stage, light precipitation and downdrafts become the dominate feature within the cloud as it weakens. In all, only twenty percent of the moisture within the cloud fell as precipitation whereas the other eighty percent evaporates back into the atmosphere.
Mesocyclone
This rotating column of air then gets picked up by the thunderstorm’s updrafts causing the entire storm to rotate vertically
Supercell
is a long-lived (greater than 1 hour) and highly organized storm feeding off an updraft (a rising current of air) that is tilted and rotating. This rotating updraft - as large as 10 miles in diameter and up to 50,000 feet tall - can be present as much as 20 to 60 minutes before a tornado forms
Squall Lines
is a group of storms arranged in a line, often accompanied by “squalls” of high wind and heavy rain. Squall lines tend to pass quickly and are less prone to produce tornadoes than are supercells. They can be hundreds of miles long but are typically only 10 or 20 miles wide.
Tornado Types
come from mainly two types of thunderstorms: supercell and non-supercell.
Tornado Alley(s)
The majority of thunderstorms in the United States form in the Midwest, called Tornado Alley, where cP air masses from Canada collide with mT air from the Gulf of Mexico, creating unstable atmospheric conditions.
Hail
is a form of precipitation consisting of solid ice that forms inside thunderstorm updrafts. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people.
Microbursts
Sometimes the moisture within downdrafts falling from the thunderstorm evaporates as it enters dryer air below the cloud. As the moisture evaporates, the air cools because of latent heat, causing the air to become denser. This in turn causes the air to fall faster. As this denser air hits the ground, it spreads out laterally producing cold winds reaching 100 miles per hour. Microbursts can uproot trees, damage property, and are very dangerous for airplanes taking off or landing.
Tornadoes
A tornado is a narrow, violently rotating column of air that extends from a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. Tornadoes can be among the most violent phenomena of all atmospheric storms we experience.
Topography determines channel:
size/shape, volume & speed of water
carried (discharge),amount (load) & size
of material (sediment) carried, flood
frequency.
Zone 1 – upper basin, steep slopes,
narrow channels
* Zone 2 – larger channels weave across
broad flat valley
* Zone 3 – near base level (ocean, lake)
Channel
The part of the stream where water collects to flow downstream, including the streambed, gravel bars and stream banks; also, a dredged passageway within a coastal bay that allows maritime navigation.
Stream
A body of flowing water
River
A large stream
Fooldplains
The flat land on both sides of a stream into which the stream’s extra water spreads during a flood
Runoff
water from precipitation (rain, snow, or ice melt) that flows over the surface of the land instead of infiltrating into the soil. It occurs when the ground is saturated, impermeable, or when the rainfall intensity exceeds the soil’s capacity to absorb water. Runoff eventually flows into rivers, lakes, oceans, or other bodies of water.
Discharge (Q):
Volume of water over time
Base flow
is the portion of a river or stream’s flow that comes from groundwater seeping into the channel, rather than from direct surface runoff.
Mean annual flow
is the average amount of water discharged by a river or stream over a year, expressed as a volume per unit time (e.g., cubic meters per second, m³/s, or cubic feet per second, cfs).
Bank full flow refers to the maximum flow of a river or stream that fills its channel to the brim without spilling over into the floodplain. It represents the flow level at which the water reaches the tops of the banks but has not yet caused flooding.
