Physical Geography - exam 2 (Wooten) MSU

what are the assumptions of the one cell model

uniform body of water, a non rotating earth

under a one-cell model, why do Low pressures occur at the Equator and High pressures at the Poles?

Equatorial High aloft (divergence aloft and convergence at the surface) Polar Low Aloft (convergence aloft and divergence at the surface)

under a one-cell model, why does air at the surface flow from the poles to the equator?

Excess amounts of mass piling up at the poles, lack of mass at the Equator on the surface, results in PGF directed from Poles to the Equator to try and distribute mass

Under the one-cell model, why does air aloft flow from the Equator to the Poles?

Excess mass at the Equator, lack of mass at poles results in PGF directed towards the poles aloft

What are the assumptions of a multi cell model

a rotating earth, a uniform body of water

What does the ITCZ stand for

Intertropical convergence zone

what is the primary lifting mechanism associated with the ITCZ?

Convergence of the Easterly Trade winds

Why does little convergence happen where subtropical highs are located?

Piling up of air aloft results in denser air that sinks and becomes the subtropical high, hindering any vertical motion (also no significant moisture within descending parcels since it was released over the equator)

What direction do the Easterly winds come from?

the east

Hadley Cell

(0 - 30 degrees N/S), convergent winds at surface due to trade winds converging, divergence aloft

Ferrell Cell

(30 - 60 degrees N/S), Divergence at surface, convergences aloft that brings winds down towards the surface

Polar cell

(60-90 degrees N/S), convergence at surface, divergence aloft

thermally direct

warm air rises, cool air sinks

what cells are thermally direct?

Hadley and Polar

Thermally indirect

cool air rises, warm air sinks

what cell is thermally indirect

Ferrel

What are the three primary jet streams and their locations?

Equatorial jet (0 degrees) Subtropical jet (30 degrees) polar jet (60 degrees)

why does the polar jet exist?

the polar jet is caused by the strong temperature gradient present in the mid-latitudes

what is zonal flow?

the east to west flow of air

What is meridional flow?

the north to south air flow

What are the names of the layers of the ocean?

mixed, thermocline, deep ocean

Why is the temp at the surface of the ocean the greatest?

it has the most solar radiation

what is a warm current

flows poleward to warm the poles

what is a cold current

flows equatorward to cool the equator

Why does he ocean have the ability to modulate weather/climate over land

high specific heat/ maritime effect

how do warm and cold ocean currents affect the overlying atmosphere differently in terms of stability

more instability is associated with warm currents (leads to rising motion), stability is associated with cold currents

On what side of continents does the warm currents lie

Eastern coastline

on what side of the continents do cold currents lie

Western coastline

what are two ways ocean currents are generated

kinetic energy of prevailing surface winds, density differences can arise from temperature or from variations in salinity

Salinity

the amount of salt in water, the more salt, the more dense the water is

what is a subtropical gyre

broad circulation with subtropical highs centered within them

What are the five subtropical gyres

North Atlantic gyre, south Atlantic gyre, Indian ocean gyre, north pacific gyre, south pacific gyre

Which gyres spin counter clockwise (northern hemisphere)?

North atlantic, Indian ocean, and North Pacific gyres

What gyres spin clockwise

South Atlantic, south Pacific

what is upwelling

removal of water from the coast

what is downwelling

piling of water along the coast

what are the benefits of upwelling

better fishing environments due to transport of nutrients towards surface

what is thermohaline circulation

controlled by differences in temperature/salinity, poleward moving Gulf Stream cools, as the water cools it becomes denser which sinks and becomes deep circulation

What does ENSO stand for

El Nino Southern oscillation

What three phases are a part of ENSO

El Nino, La Nina, neutral

El Nino oscillation

More convergence on the western portion of North America, more hurricanes on the California/Mexico coastline, warmer ocean temps along cali/mexico coastline

La Nina oscillation

More convergence on the eastern portion of North America, more hurricanes in the Gulf of Mexico/Caribbean sea, colder ocean temps along cali/mexico coastline

When is rising motion the strongest/weakest in the western equatorial Pacific

Weaker in El Nino. Stronger during La Nina

When is rising motion strongest/weakest in the central/eastern equatorial pacific

stronger during El Nino, Weaker during La Nina

Air mass

an immense body of air characterized by generaly uniform conditions

How are air masses classified

by humidity and temperature

Air mass with the most humidity

Maritime

Air mass with little humidity

continental

Air mass with warm temperatures

Tropical

Air mass with cold temperatures

Polar

Air mass with extreme cold temperatures that is only prevalent during the winter

Arctic

specific humidity

refers to the weight of water vapor contained in a unit of air

relative humidity

the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature

what are the differences between cold and warm fronts

cold fronts are thin in height and contain stable air while warm fronts are thick in height and contain unstable air

What are the four types of fronts

warm, cold, dry, stationary

what is a front

boundary between differing air masses with sharp gradietns in temp, density, and mouisture

what is a warm front

a boundary of warm air replacing cold air

what is a cold front

a boundary if cold air replacing warm air

what are the four lifting mechanisms

orographic, frontal, convergence, convection

What is orographic lifting

air is forces to rise when it encounters a mountain

what is the rain shadow effect

as air rises, it cools and condenses into clouds and eventually wains on the windward side of the mountain. On the leeward side of the mountain, the now-dry air sinks and warms.

Convergence lifting

when winds near Earth's surface are forced upwards when colliding

Frontal lifting

when cool air in a cold front forces the warm air to rise

Convective lifting

the result of uneven surface heating that causes parcels of air to rise

What are the three condition for an air mass thunderstorm to develop

unstable atmo, moisture, some type of lifting mechanism

What are the three stages of a thunderstorms life cycle

developing, mature, dissipating

developing stage of a thunderstorm

updraft only, storm is building

Mature stage of a thunderstorm

Updraft and downdraft, storm is fully formed

dissipating stage of a thunderstorm

downdraft only, storm is dying

why does an air mass thunderstorm only last 30-60 minutes

because the storms downdraft eventually weakens and totally replaces updraft which is the fuel source

What are the severe thunderstorm criteria

wind greater than 58 mph, hail, tornado

Why do severe thunderstorms last longer than air mass thunderstorms

because the updrafts and downdrafts are able to stay separate from each other

squall line

a line of strong storms that forms along a frontal boundary

supercell

individual thunderstorms that rotate on their own

lightning

electrical discharge from storm

how hot can lightning get

6x hotter than the sun

how can lightning strike

cloud to cloud, cloud to ground, cloud to air

hail

a type of thunderstorm precipitation

how does hail form

when water freezes and melts repeatedly in the downdraft, eventually becomes too heavy and falls to the surface

What are the 6 different climates in the Koppen Climate System

A,B,C,D,E,H

What is A in the koppen climate system

Tropical

What is B in the koppen climate system

dry

What is C in the koppen climate system

Mild

What is D in the koppen climate system

Mid latitude

What is E in the koppen climate system

Polar

What is H in the koppen climate system

high altitudes (think mountains)

why is recent global warming likely the result of man-made emissions?

excess of greenhouse gas and carbon emissions