earth proc and risks quiz VI

Explain the river channel patterns and where they are located: Bedrock rivers, meandering rivers, braided rivers, delta

1) bedrock rivers: there is a steep slope. High energy, high erosion. 2) Braided or meandering have a lower slope, a low velocity, and low energy, which results in deposition. at the very end if the river goes into the ocean, the current slows and deposits its fine sediments forming a delta.

how are tornados formed?

1) supercell--formation of mesocyclone (rotating air about a vertical axis) 2) wall cloud formation: rain creates rear flank downdraft that pulls mesocyclone down. wall cloud forms as rotating cell drops below cloud base (supercell, downdraft makes mesocyclone down, wall cloud) 3) as wall cloud descends, smaller more rapidly rotating funnel cloud forms within or next to the wall cloud. - as the funnel cloud reaches down towards ground tornado forms (often at the back of a storm) as tornado matures, it widens and becomes more intense

thunderstorm ingredients in the cumulus, mature, and dissipating stage: 1) 2) 3)

1) warm humid air must be present in the lower atmosphere 2) a steep vertical temperature gradient through atmosphere there is a strong updraft in the mature stage and a gust front. 3) updrafts must form warm humid air upward into colder air

tornado moves forward at 50-80 km/hr (30-50 mph) but rotating winds can be over 500 km/hr (>300 mph). _____ times the max speed of hurricane winds

2

stream channel and adjacent floodplain occupy <1% of land area on earth. about ____% of US land is floodplain and home to about ___% of the population (mostly midwest)

2.5; 6.5

discharge rate in the mississippi: - 200 cubic meters/second - 2,000 - 20,000 - 200,000 the mississippi river drainage basin is composed of multiple smaller river drainage basins including ____, ____ and ____ rivers. drainage basin is an area of land where all surface water from rain, melting snow converges to a single point at a lower elevation. a large river/drainage basin may be composed of hundred of smaller watersheds (Catchments)

20,000 (317 million gallons/minute: 1 min is enough water for 2,200 families for a year); missouri; arkansas; ohio

lightening travels at speeds of ______ km/hr. it heats air within its narrow path to over 28,000C 50,000F ____ is fused sand from a lightening strike

220,000; fulgurites

Lightening: - about _____ a year as compared to 15,000 homicides a year, and 33,000 car fatalities a year. accounts for ____ of all natural hazard deaths in the US>

53; 11

breakdown of recorded economic damages in us dollars by disaster type

69% 1.9 trillion are weather-related 36% storm related

what are conditions that favor supercell formation--therefore tornados?

most tornados occur in the afternoon and in the summer. texas--ohio

why does the US lead the world in number of tornadoes?

N America extends from tropics to arctic without any east west mountain ranges to block air flow

what is a 100 year flood? how do we determine it?

If we know n, the total number of years in record and m, the rank of the flood, then we can calculate the recurrence interval R, or the frequency in years of a flood event of a particular magnitude of discharge (the average volume flowing at any point along the watersheds) a best fit line is drawn through the data points, allowing you to determine the discharge associated with a 100 year flood. R = (n+1)/m recurrence interval (the frequency of a flood event of a particular magnitude of discharge) is the number of years on record + 1 / the rank of the flood.

warm air can rise due to ___ ___ or ____. But more commonly as cold air and warm air collide and :____ a) cold air pushes under warm air b) warm air pushes under cold

Instability is caused warm air rising due to local heating or topography. as cold air and warm air collide, the cold dense air pushes under the warm air (cold air is more dense than warm air)

____ ____ ______ are cyclic changes in atmospheric conditions and sea surface temperatures (SSTs) that cause warm or cold weather, droughts, heavy precipitation, floods. _____ is best known of these climate oscillations;also discussed Pacific Decadal Oscillation and Atlantic Multi-decadal oscillation

Regional Climate oscillations; El Nino/La Nina southern oscillation (enso) the el nino condition has rising moist air in the center and descending dry air on the left and right. Causes warm water pool in the center and downwelling and upwelling. the la nina/neutral condition has the warm water pool on the left. There is descending dry air only on the right, and then cold, nutrient-rich upwelling of water from south america to indonesia

t/f: bedrock rivers are fast moving, high energy streams in steep mountainous areas with hard rock stream bed. They lack sediment (alluvium) in their channels

T

t/f: almost all damage caused by tornados is due to extreme winds and flying debris t/f: cows are easily lifted by tornados

T; t (heaviest thing lifted was 30,000 pounds; furthest distance 100 miles)

what is a microburst and why is it particularly dangerous to aircrafts during takeoff and landing?

a microburst is the most violent form of a downdraft. It is developed when the rain falling from a thunderstorm evaporates under a cloud and cools the air beneath. So it is essentially a localized downdraft that can be as fast as 168 mph. it is dangerous to aircrafts because it can push the plane up during takeoff, because there is increased airspeed associated with an increased headwind. BUT when the plane is landing, there is a strong downdraft. reduced airspeed caused by increasing tailwind.

a _____ ____ is a leading edge of cold air rushing downward and outward from a thunderstorm

a gust front is a leading edge of cold air rushing downward and outward from a thunderstorm (this is different from a cold front because a cold front is when cold air pushes warm air up, and warm front is when warm air moves over a cold air mass)

erosion in bedrock rivers occurs by a combination of ___ and _____.

abrasion; plucking

there can be dramatic changes in calculated recurrence intervals for the same 1994 flood, from 113 years to to 43 years. how does this happen?

after 1994, there can be a flood that is slightly larger (m1997= 1 and m1994=2), and now n=115. so 115 + 1/ 2 = 58 years. This can go on while there are floods that are slightly larger than the original one, until the recurrence interval becomes smaller.

what makes floodplains important to humans?

agriculture (soils are rich for farming); habitat (diverse and rich environments for different plants, birds etc); flood mitigation(floodplains take on excess water and release slowly into groundwater--reducing risk of property damage downstream); groundwater recharge; transportation (floodplains support shipping as the flat, rock free land lends itself to road and railroad development and is located close to agricultural land)

______ ___ is a cone shaped deposit of sediment formed as the flow of a river decreases in velocity. Sediment is fed from a single point source at the apex of the cone where the stream enters. Across it, braided streams move to occupy many positions on the fan surface

alluvial fan

for basins, as distance increases, depth tends to _____ (increase/decrease). as depth increases, velocity tends to ______ (increase/decrease).

as distance increases depth increases then decrease (deeper water in higher regions up top at beginning of river). as depth increases, velocity DECREASES. fastest velocities are at the center of the stream - doppler shift measures the velocity in the stream. Flux is velocity x area.

how is hail formed?

as moisture rises, it freezes into ice and then ice crystals become heavy, so sink though the updraft. becomes a kind of cycle where moisture is added and frozen to the hail stones. more powerful updrafts produce larger hailstones the largest hailstone was the size of a volleyball--8 inches in diameter. they develop concentric rings associated with multiple ascents and descents through the freezing level in the storm cell a hailstone the size of a baseball weighs about 150g and can fall at speeds of 100mph. up to 3 billion a year in damages to crops, buildings, vehicles, airplanes

Recipe for making a thunderstorm

as warm moist air rises, it cools. its water vapor condenses into liquid droplets, forming clouds condensation releases heat, causing the air to be warmer and to rise even faster, creating further instability and updrafts. (precipitation, condensation, thunderstorms, instability, often occur with cold fronts) this is *positive feedback*

what is the difference in the shape of a river at the headwaters v the base level?

at the head waters, the river valley is v-shaped. it becomes wider as it reaches the lower levels of a river system (the base level)

____ are fast moving high energy streams in steep mountainous areas with hard rock stream bed. ____ are most common and sweep from side to side in wide turns. _____ rivers tend to occur in dry climates with abundant coarse sediments

bedrock rivers fastest; meandering rivers most common; braided occur in dry climates with coarse sediments. most streams and rivers fall on a continuum between meandering and braided

greatest potential for downbursts (strong downdraft produced by convective storm; cold descending air masses that spread out radially as straight line) is near the ________ of the squall line. Where in the squall line are tornados most prone to development?

center of the squall line; tornadoes most prone to develop on the high edge where the wind is rotating counter clockwise

___ flooding is caused by storm surges, extreme tidal conditions, and sea level rise. Relatively narrow strip of it. ____ flooding is caused by intense rain and large runoff, saturating drainage systems (common in urban areas)

coastal flooding is caused by storm surges and extreme tidal conditions, sea level rise; pluvial/surface flooding caused by intense rain and large runoff saturating drainage systems (within this category is overbank flooding in low topography and flash flooding in steeper topography associated with thunderstorms)

in a cold front, ____ advances against _____ air, causing rapid uplift of _____ (cold/warm) air. Instability, condensation, precipitation, and often thunderstorms result. In a warm front, ____ air advances over ____ air. Widespread clouds and precipitation result

cold air advances against warm air, causing a rapid uplift of warm air. in a warm front, warm air advances over cold air *Severe weather is often associated with weather fronts, boundaries between cold and warm air masses*

in the US ____fronts (cold/warm) are the most common in a northeast trending area from Texas to Ohio, where cold air from the ____ plains and Canada meet warm moist air from the Gulf of Mexico

cold; northern

a _____ cloud is a towering cloud as high as 12 km or more with a flat anvil like top; because the atmosphere is divided into layers based on temperature, warm air rises until it hits the layer of warmer air in the ______ and then spreads out into the anvil shape. The level of neutral buoyancy where clouds stop growing upward is here.

cumulonimbus; stratosphere, just above the tropopause

Atmospheric fundamentals: 1) Warm air is less dense than cold air 2) Air flows from high pressure to low pressure 3) Warm air holds more water vapor than cold air 4) Decreasing air pressure causes air to ______ (expand/contract) and cool. Increasing pressure _____ (warms/cools) air. 5) coriolis effect deflect motion of air masses to the ____ in northern hemisphere and the ___ in the southern hemisphere

decreasing air pressure causes it to expand and cool; increasing pressure causes it to warm; right in northern hemisphere, left in southern

what is the power-law relationship between stream discharge and drainage basin area?

discharge is the average volume of water flowing at any point along the watershed, the drainage basin is an area of land where all surface water from rain, melting snow converges to a single point at a lower elevation. SO a *10* fold increase in drainage area leads to a *10* fold increase in discharge (10 fold increase in volume of water flowing) so if drainage area is 10 and increases 10 fold (100), and the bankfull discharge is 1,000, it increases 10 fold (10,000)

t/f: As a tornado dissipates, it narrows and becomes rope like. The rotating wind is slowing down

f (the rotating wind is speeding up due to the conservation of angular momentum; tighter radius can cause wind speed to increase, so still very dangerous)

in the third stage of thunderstorm generation (after the cumulus stage, mature stage with formation of hail or melting of small ice particles), there is the dissipating stage. thunderstorms typically start to dissipate after ____ minutes to _____. This occurs when _______ dominate the ______. Because the moist air can no longer rise, cloud droplets no longer form. in severe thunderstorms, this stage can be prolonged because _______ and the rainfall foes not cut off the inflow of moist warm air

dissipate after 30 mins to an hour; dissipation occurs when downdrafts begin to dominate over the updraft; the moist air cant go up anymore, so cloud droplets dont form anymore. with severe thunderstorms, this stage can be prolonged because updraft region is slanted and the rainfall does not cut off the inflow of warm moist air

a gust front or downburst causes most destructive winds during thunderstorm?

downburst - gust front us a leading edge of cold air rushing downward and outward from a thunderstorm, while a downburst is a strong downdraft produced by a convective storm. cold descending air masses that spread out radially as straight line. winds with speeds up to 125 mph.

___ ____ are places where you go from one drainage basin to another; describe the boundary between different drainage basins.

drainage divides - in the us, drainage basins empty into the atlantic, pacific, and arctic oceans, the gulf of mexico and the hudson bay. the great basin is an internal drainage basin that does not empty into any ocean

the largest number of fatalities associated with natural disasters is ______. then storm, flood/extreme temp

earthquake (the combined weather-related disasters claimed about 600,000 lives)

how do the rising and sinking particles work with lightening? Lightening forms as ____ ___ builds between top and bottom of cumulonimbus clouds

electric charge builds between top and bottom of cumulonimbus clouds. at top of cloud, positive charge. At bottom, negative charge. rising particles in the cloud acquire a positive charge and sinking, a negative. as charge separation increases within the cloud, then - charge at cloud begins to attract positive charged + particles from the ground to higher points. eventually lightening results as connection is made

t/f: cloud to ground is most of all the lightening strikes

f (cloud to ground is only 25%. most of the strikes are cloud to cloud, so negative at bottom of cloud to positive at top of cloud)

t/f: in semi arid regions, runoff is slower than in wet regions

f (in semi arid regions, runoff tends to be faster because impermeable surface like clay and the lack of vegetation make it less likely to absorb water. cold areas' frozen soil cannot easily absorb water either. Wild fires can also seal soil surface, reducing the soil's ability to absorb water. same for water saturated soils. but in wetland areas, plants act as natural sponges that absorb water and slowly release it over time)

t/f: the great drainage basin is a basin that empties into the atlantic

f (the great drainage basin is an INTERNAL drainage basin that does not empty into any ocean)

a _____ cage is a metallic enclosure that prevents the entry of an electromagnetic field. as this cage _____ that charge or radiation around the cage's exterior, it ____ electric charges or radiation within the cage's interior

faraday cage is a metallic enclosure that prevents the entry of an electromagnetic field. It distributes the charge or radiation around the exterior and cancels out the electric charges or radiation within the interior

flow velocity and erosion/deposition in a stream: faster flow along the outer bank results in ____, forming ___ ____ slower flow along the inner bank results in ____, forming ___ ____. Meandering rivers are favored in systems with large amounts of ___ ____.

faster flow faster flow along the outer bank results in erosion, forming cut banks. slower flow along the inner bank results in deposition, forming point bars. meandering rivers are favored in systems with large amounts of suspended sediment 6

these conditions favor ____ over _______ (Meandering/braiding) rivers. - low or variable discharge relative to load - high bed load relative to suspended load - high erosion rates non cohesive bank materials - rapid decrease in slope, forming an alluvial fan

favor braiding over meandering

how are natural levees formed?

finer sediments settle out across the surrounding flood plain. When streams overrun their banks, water velocity slows dramatically, and coarse sediment drops out first to dorm natural levees.

____ are among the deadliest and costliest weather-related hazards. annual costs of -- damage increased 10x from 1929-2003, from 400 mil to 4 bil.

floods

when does flooding occur? Use discharge, water velocity, water depth, and stream width in your answer.

floods occur when the discharge becomes too large to be accommodated by the normal stream channel (discharge is the average volume of water flowing at any point along the watersheds). during a flood, water velocity, water depth, and sometimes stream width increase. water overtops stream banks and floods low-lying areas surrounding the stream (floodplains) - low flow happens 90% of the time, mean flow 30% of the time, bankfull flow 2 times in 3 years on average; moderate flood every 10 years on average. This and the bankfull flow leads to channel erosion.

the most lightening strikes occur in the state ______. it is most common in tropical areas where there is a lot of moisture in the air to drive thunderstorm formation. There is a seasonal cycle with storms occurring more frequently in the ____ months.

florida; summer

describe each stage of the downburst life cycle: 1) in the formation stage, evaporation and precipitation ____. 2) impact: the downdraft______ 3) downdraft moves ____

formation: Evaporation and precipitation drag forms downdraft; impact, downdraft quickly accelerates and strikes the ground; dissipation: downdraft moves away from point of impact (a microburst is a localized downdraft, the most violent form. develops when the rain falling from underneath a thunderstorm evaporates underneath the cloud, cooling the air beneath. these are particularly dangerous during takeoff and landing of aircrafts)

explain formation of oxbow lake

formed from abandoned river meander, after stream breaks through narrow neck separating meanders. meanders shift from side to side. the current is faster at the outside banks, which are eroded. sediments get deposited at inside of the bank where the current is slower (point bars). as the erosion and deposition process continues, the bends grow closer and the point bars bigger. during a major flood, when velocity and water volume increase, the river takes a new shorter course cutting across the loop. the abandoned loop remains an oxbow lake

some of the precipitation in an area percolates through soil to become groundwater and is collected by rivers and streams. What is the difference between gaining and losing streams?

gaining streams are fed by combination of surface runoff and groundwater. typical of WET climates. losing streams fed by runoff (water moving along the surface) but lose water into ground water. TYPICAL OF DRY climates

hail formation is different from sleet and freezing rain: Hail is the result of ____ during thunderstorm formation sleet is rain that falls ______ freezing rain is rain that falls and ______

hail is created through strong updrafts, and sinking as the chunks become too large for the cloud to hold. causes strong downdraft. Cycle of upward and downward, convection currents, above and below the freezing level. Rain drops are sucked into the updraft for sleet and freezing rain, the air above is warmer, above freezing, and the air closer to the ground is colder, or below freezing. For sleet, the warmer air is less close to the ground, so the rain falls through a layer of cold sub freezing air before hitting the ground. for freezing rain, the rain falls and freezes ONCE It hits the ground. sleet and freezing rain are both common in winter storms

in a river, where is the zone of erosion, the zone of deposition, the zone of transport?

in the steeper gradient, near headwaters, the river is dominated by erosion. in the shallower gradient, at the base level where the cross section is less of a v shaped and flatter, the river is dominated by deposition. Between these two areas is the zone of transport of water and sediment

what influences stream load?

increase discharge (flow velocity and cross sectional area) and increase water level causes the stream load to increase. there is the most erosion with sand, less with gravel. as particle size increases, more deposition of particles.

a river/stream/creek is a body of water that flows ______ in a _____ and carries ______ all streams accumulate surface water ___ and ____ from their watersheds.

it is a body of water that flows downslope in a channel, and carries a load of sediment and dissolved matter. All streams accumulate surface water runoff and groundwater from their watersheds. (gaining streams are fed by a combination of surface runoff and ground water. Typical of WET climates. losing streams are fed by surface runoff, but lose water to groundwater. Typical of dry climates)

What is flood intensity based on?

it is based on *stream stage* (the stream/flood height) and the *streamflow* (discharge, average volume at any given point). the stream stage and streamflow depends strongly on the rate of *SURFACE RUNOFF*, which also depends on - *meteorological factors* (rate and duration of precipitation and snow melt, location and distribution of precipitation) - *physical characteristics* of the environment like ground condition, permeability - *human activities*

During condensation, air releases small amount of heat called _____. As condensation occurs in rising air, ______ is released and the air becomes ___ (warmer/cooler) than the surrounding and ______ (sinks/rises)

latent heat; air becomes warmer; continues to rise

the flood intensity (stream stage height and stream flow discharge) is determined by surface runoff, which is influenced by meteorological factors. What are some examples and their impact on the environment?

light rain or slow snow melt is easily absorbed into the ground with little immediate runoff into streams. heavy rain or rapid snow melt cannot all be absorbed into the ground, and creates a lot of immediate runoff into streams. thunderstorms, hurricanes, el nono and la nina events, and monsoons can all produce heavy rains that overwhelm soils' capacity to absorb water. flood intensity also depends on the distance of the storm (storm location and distribution). The hydrograph shows a plot of stream discharge v time. upstream floods tend to have higher flood crests and can result in more frequent flash floods than downstream areas

the ___ ___ of a river system is the average gradient measured in the downstream direction along the entire river length elevation vs distance.

longitudinal profile at high elevation, draining smaller area. Larger catchment area as distance (downstream) increases and elevation decreases. The top elevation is known as the head waters. the lower point is the base level. along the river there can be local base levels, like lakes, that stop erosion.

rate of runoff depends on topography. there is a ______ rate of runoff on flat land (high/low).

low rate of runoff on flat land; steep slopes and lack of vegetation increase rate of runoff.

most deaths are due to ____ (lower/higher) Intensity tornadoes

lower

the ___ is a vortex of spinning air within a convective storm system. (windshear--tube air mass--updraft makes air upright--updraft itself rotating) _____ can form out of mesocyclones. Wind shear physically separates downdrafts from updrafts and causes the cell to rotate they are stable for *longer* periods of time than typical thunderstorms

mesocyclone is a vortex of spinning air within a convective storm; supercells can form from mesocyclones. the wind shear physically separates updrafts from downdrafts and causes the cell to rotate. supercells are stable for longer time periods than the typical thunderstorm

a ____ is a localized downdraft, usually less than 2.5 miles in diameter; max wind speeds of 168 mph; and they are the most violent form of a down draft (downburst is a strong downdraft produced by a convective storm). they develop when rain falling from a thunderstorm evaporates underneath the cloud, cooling the air beneath

microburst

regional wind patterns: southern asian ___ are seasonally reversing periods of: - mild winter breezes from northeast in winter and - _______ winds and rain in the summer

moisture laden southwesterly winds and rain in the summer air over the land heats up during summer, generating a low pressure system that drives winds from the southwest off the ocean

how is hail formed in severe thunderstorms?

moisture rises and freezes into ice. Ice crystals grow until they are heavy enough to fall down through updraft. more powerful updraft means larger hailstones 1) rise, ice 2) heavy, fall through updraft 3) stronger updraft, stronger hail hair circulates and grows within convection currents hail causes up to 3 billion dollars yearly in damages to crops, livestock, buildings aircraft etc.

flood records can be extended to better understand flood height and recurrence intervals, using historical records and paleoflood evidence. What are some examples of this?

physical evidence of past flooding preserved in the geologic record. - used to estimate paleoflood height - critical information on minimum hazard of past flood - silt and sand deposits on sheltered parts of floodplains - organic material can be dated with radiocarbon methods to indicate dates of floods - tree scars: can count the rings between scars to determine the recurrence interval of major floods that affected the tree

the exceedance probability of a certain discharge (flood) in any single year = 1/R (recurrence interval). So a 10 year flood would have 1/10 = 10%, or ________ what is a 100 year flood exceedance probability?

probability in any year that a flood with a discharge equal to or greater than that of a 10 year flood would occur. if the discharge is 200 for a 10 year flood, then this is the probability in any year that a flood with a discharge of 200 of a 10 year flood would occur. a 100 year flood exceedance probability = 1/100, so 1% probability in any year that a flood with a discharge equal to or greater than that of a 100 year flood would occur

Fluvial/river floods are caused by ________ exceeding the river's capacity. ____ ___ occurs in large rivers with LOW topography. High water inundating extensive region for weeks. Few deaths but extensive damage ____ ____ occurs with local thunderstorms with STEEP topography. can occur in deserts many miles away from the storm and accountable for the *most flood-related deaths*, 50% car-related

prolonged heavy rain and by snow melt and ice blockage that exceed the river's capacity; *overbank flooding* happens in large rivers with low topography. *flash flooding* happens with local thunderstorms in areas of steep topography, but can also occur in deserts many miles away from the actual storm

____ rivers consist of a network of river channels separated by small islands or bars. they are overloaded with sediment which is deposited in the channel, clogging it an forcing the water flow to shift from side to side around deposit. They are characterized by abundant ___ __ carried along stream bottom. frequent in ___ climates, with ___ sediment

raided rivers consist of a network of river channels separated by small islands or bars. they are overloaded with sediment which is deposited in the channel, clogging it and forcing the water flow to shift from side to side around the deposit. They are characterized by abundant *bed load* carried along the stream bottom. braided rivers are frequent in *dry climates* with *coarse* sediment

what are tornadoes?

rapidly rotating columns or funnels of high winds that spiral around narrow regions of low pressure beneath a thunderstorm - visible because of condensation, dust and debris - most often form from powerful thunderstorms or hurricane systems

in a doppler radar, the ____ refers to the amplitude of the radar return and the ____ refers to the phase shift of radar return

reflectivity (amplitude) ; wind velocity (phase shift)

classify the basic thunderstorm types as 1) nonsevere to severe, or 2) definitely severe - single/ordinary cell - multicell clusters - multicell squall lines - supercell What defines a severe thunderstorm ?

supercell is only definitely severe; (warm humid air, vertical temp gradient, updraft warm air to cull air, wind shear mesocyclone separate updraft from downdraft). requirements of a severe thunderstorm is when ONE of the following criteria is met - wind gusts 58 mph or faster - hail of 1 inch in diameter or bigger - thunderstorms that produce 1 tornado or more

what factors influence the stream stage (stream/flood height) and stream flow (discharge) -- note that these both determine the flood intensity.

surface runoff--depends on - meteorological factors (rate and location of precipitation, snow melt, location and distribution of it) - physical characteristics (topography of the environment, permeability and saturation, distance from the water source e.g. storm) - human activities

t/f: outward straight line winds from downbursts can be as damaging as some tornadoes

t

t/f: a drainage basin is an area of land where all surface water from rain, melting snow converges to a single point at a lower elevation

t (a large river drainage basin may be composed of hundred of smaller watersheds (catchments); Tributary system is a smaller stream that feeds into a larger stream or river)

t/f: severe weather is often associated with weather fronts, boundaries between cold and warm air masses

t (thunderstorms, precipitation, instability, condensation associated with cold fronts and clouds and precipitation associated with warm fronts)

a terminal doppler weather radar is a radar system with a 3D narrow beam that used for the detection of hazardous wind shear conditions, precipitation, and winds aloft on and near major airports. how does the system work with wave compression? what are the two things that it measures?

take a police car for example: as car is approaching you, waves compress, increasing pitch. as moves away, stretches, decreasing pitch. the police officer has a radar gun that sends out waves, and then the reflected waves come back at a higher frequency after they hit yur car. the two components are reflectivity, or the amplitude of radar return and the wind velocity, or the phase shift of radar return.

relative humidity: amount of water vapor in air/ amount of water vapor air can hold. the amount the water vapor air can hold is determined by ____

temperature (the temp at which air's relative humidity is 100% is called the dew point. At the dew point, water vapor will condense into droplets)

explain thunderstorm generation: three things

temperature: rising air expands and cools (adiabatic cooling). descending air compresses and warms (adiabatic warming). Moisture: rising air can take less and less water vapor as it cools (expanding but lower capacity to hold vapor) so it eventually will reach 100% relative humidity, condensation, and precipitation

the ability for river water to carry sediments depends on the _____ and ____ of the -- to lift particles. the particle types are divided into three categories: _____ ___ is matter transported in the form of chemical ions ___ ____ is composed of fine sediment particles (silt and clay) that are suspended ___ __ are particles that are too large to be suspended (sand, cobbles, boulders) but roll along floor of stream

the ability of river water to carry sediment depends on the flow velocity/discharge and turbulence of the flow to lift particles. dissolved load is matter transported in the form of chemical ions suspended load is fine sediment suspended by turbulence bed load are particles that are too large to be suspended like the finer sediments

what is discharge? how is it measured? 1 min of mississippi river discharge is enough for ___ families a year

the average volume of water flowing at any point along the watershed the Q(discharge)= VA V= average velocity A= The cross sectional area of the stream, or width times depth; 1 min of water in the mississippi is enough for 2,200 families for a year

THUNDER is the rapid ____ _____ of the heated air that creates a _____ ___ heard as a booming noise. because of a differences in speed, time interval between arrival of light and sound can estimate the distance (______)

thunder is the rapid *supersonic expansion* of the heated air that creates a *shock wave* heard as a booming noise; the difference in time between light and sound can estimate the distance of the lightening. 3sec/km or 5sec/mile

how does vertical wind shear lead to thunderstorm formation?

thunderstorm formation can interact with wind shear to create supercells. There is a thunderstorm forming (so warm air rising, condensing) and there is an updraft, pushing the spinning tube created by the vertical wind shear up. 1) wind shear creates a spinning tube like air mass 2) the updraft tips the spinning air upright and then the updraft itself begins to rotate. This vortex of spinning air within a convective storm system is called a *mesocyclone*

Single ordinary cell systems consist of one main ____ (updraft/downdraft) system. multi cell systems is a combination of cells in different stages of formation. They can occur in ___ or as ___ ___.

updraft; clusters; squall lines

the initial uplift and condensation of warm moist air forms ___ _____. Rising air causes ____ at ground level. Puffy low level clouds have a flat base

uplift and condensation of warm moist air forms cumulus clouds; rising air causes updrafts at ground level - these clouds grow vertically to a height of around 6 km - cumulus clouds are often seen in the afternoon, as the sun heats the earth's surface and warms the air around it - the warm air rises and if the air is moist, then it will condense into a cumulus cloud - the cloud will continue to grow as long as warm air below it continues to rise

what is the difference between upstream floods and downstream floods in terms of their flood crests on a hydrograph

upstream floods tend to have higher flood crests and can result in more frequent flash floods than downstream areas. downstream floods tend to be less violent but can affect far more people

wind shear is defined as horizontal or vertical. _____ is the change in wind velocity as a function of elevation. - it can organize air circulation into rolls that spin with a horizontal axis of rotation. The faster winds are on the ____ and the slower on the ___ (top/bottom)

vertical wind shear is the change in wind velocity as a function of elevation. there is air circulation rotating around a horizontal axis, and the faster winds are on the top and slower on the bottom near earth's surface

What three things do thunderstorms require?

warm air (heat); moist air (moisture); instability of surface air mass (lifting mechanism; rising of air mass due to its buoyancy)

regular patterns of rains are important for agriculture throughout asia

warmer ocean, precipitation out at sea in the winter. cooler ocean, high pressure. Spring/summer warmer land low pressure. precipitation on land

in the second stage of thunderstorm generation (after the cumulus stage where warm air rises and condenses at about 6 km high), the *mature stage* consists of water droplets _____ing into particles. when they are small and fall, they _____. if updrafts is strong enough, these particles become _____. falling rain and --- produce ___ that mix with updrafts and create unstable conditions that result in lightening, strong wind, and tornadoes.

water droplets freeze into ice particles; when they are small and fall, they melt to become rain, but when the updrafts are large enough, then the ice particles grow into hail. falling rain and hail produce downdrafts that mix with updrafts and create unstable conditions that result in lightening, strong wind, and tornadoes

Formation of natural levees: when streams overrun their banks, water velocity _____ and coarse sediment drops out ____ (first/last) forming natural levees

water velocity *decreases* dramatically and coarse sediment drops out *first* to form natural levees (the finer sediment settles out across the floodplain) meanders erode outwards and slowly migrate downstream, creating a broad eroded basin called a floodplain.

_____ is the condition of the atmosphere at a particular time and place (timescale minutes to months) ____ refers to the average characteristics of a given region (30+ years timescale)

weather is the condition of the atmosphere at a particular time and place, whereas climate is the average weather characteristics of a given region

what happens to the deposition and transport of particles when there is low flow speed and a faster speed?

when there is a low flow speed, the particles aren't transported as much. when there is a higher ones, the smaller particles tend to move farther, but all the particles are transported more in general. the average grain size typically decreases downstream

lightening during a dry thunderstorm can cause _____. what are the percentages of occurrences of natural disasters world wide, top 3?

wildfires; 43% flood; 28% storm; 8% eq

Doppler radar, _____ ___ and ___ _____ are used to predict possible tornado formation and detect ones on the ground. While siren systems get message out, warning times are typically ___ minutes or less.

wind profilers; automatic surface observing systems; 15

name the difference between necessary conditions for a thunderstorm and a supercell, and the conditions they both require

wind shear; warm humid air, temp gradient, updrafts 1) *warm humid* air is present in the lower atmosphere 2) a steep vertical *temperature gradient* through the atmosphere (so warm air rising can we warmer than the surrounding air) 3) the *updrafts* must force warm humid air upward into the colder air 4) the wind shear separates the updrafts from the downdrafts, and causes the cell itself to rotate. the mesocyclone is the vortex of spinning air within the convective storm system. (the supercell forms out of the mesocyclone because of this windshear)

Enhanced Fujita (EF) ratings refer to the ______ and _____. (0-5)

wind speed; expected damage (0 is 65-85; 1 is 110; 5 is >200)

with increasing distance from the headwaters the slopes of the longitudinal profile ____ (increases/decreases) and the area of the drainage basin _____ (increases/decreases). what is the shape of the longitudinal profile for a system in equilibrium?

with increasing distance from the headwaters the slopes of the longitudinal profile decreases and the area of the drainage basin increases; the longitudinal profile is concave up, provided that it exists in a system of equilibrium. Plot elevation on left and distance on right.