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currents Flashcards

1
Q

what are surface currents?

A

masses of water that flow from 1 place to another

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2
Q

what force drives surface currents?

A

friction from the energy of wind passed to surface waters

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3
Q

explain the movement of air to create wind belts

what is the zone called

A
  1. warm air f/ equator rises northwards
  2. at 30 degrees N/S, air cools and sinks to equator

intertropical convergence zone/doldrums

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4
Q

What causes the surface layer to move?

A

drag of winds

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5
Q

Name some wind belts in the Atlantic

what are they influenced by

A

Westerlies
tradewinds

position of continents

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6
Q

What are gyres?

A

large loops of water in ocean basin (circles)

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7
Q

how many main gyres are there?
name them

A

n pacific
s pacific
n atlantic
s atlantic
indian ocean

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8
Q

What is the latitude of the centers of ALL gyres?

what do you call this region

A

30 degrees s/n

subtropical

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9
Q

how many main currents does each gyre have?

A

4

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10
Q

the coriolis effect explains…

A

how currents are deflected

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11
Q

which way are currents deflected in the N.Hemi and what direction do gyres move there?

A

to the right
clockwise

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12
Q

which way are currents deflected in the s.hemi and which way to gyres move there?

A

left
counterclockwise

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13
Q

how many years does it take for an object to make a trip aroun the N.Atlantic Gyre? N. Pacific?

what sea is in the N.Atlantic? what is it known for

A

3yrs
6yrs

sargasso. calm waters/seaweed

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14
Q

What is the only current that encircles Earth?

A

West Wind Drift

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15
Q

why does the west wind drift go around the earth completely

whaat wind belt is moving it?

where does it split off

A

travels through Antarctica, which lacks landmasses

westerlies

s ocean basins

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16
Q

what does the movement of surface water match up with?

A

global pattern of prevailing winds

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17
Q

what is the indian ocean influenced by?

definiton

A

monsoons

seasonal wind shifts

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18
Q

a change in wind direction leads to a change in

A

surface current direction

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19
Q

describe the transfer of solar radiation from low latitudes

A

get more solar radiation than they release

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20
Q

what are the agents of heat transferr

what percentage does each agent hold in heat transport

A

winds and ocean currents to balance out deficient and excess areas

winds: 3/4; ocean currents: 1/4

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21
Q

When do warm currents exert greatest influence

A

winter

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22
Q

what is the extension of the gulf streamm called

A

north atlantic drift

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23
Q

is the gulf stream warm or cold

A

warm

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24
Q

when is the influence of cold ccurrents most pronouced?
Coast vs inland

A

topics/summer months at mid latitudes

Coast: feel cold current lower temps in summer but very hot on east coast

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25
how do currents flow? | what is the temperature of these currents
from low latitudes to high latitudes hot to cool | warm
26
how many miles does the gulf stream move?
25-75 miles per day
27
where is aridity intensified?
west coasts of subtropical deserts
28
why is aridity intensified along the west coasts of subtropical deserts?
cold offshore water cools atmosphere, stabilizing it, and preventing precipitation
29
what is another reason why aridity is intensified along the west coasts of subtropical deserts
cold currents=temps near dew point=foggy and humid
30
what is upwelling
rising of cold, deep water to warm, surface water
31
what is coastal upwelling characteristic of?
west coasts of continets
32
how do the winds blow in accordance to upwelling
toward equator and parallel to shore
33
how do the winds and the coriolis effect affect surface water
surface water moves away from the shore which allows it to be replaced by cold water
34
Nutrients and upwelling
nutrient concentration increases = more plankton=high productivity
35
weather of SF in summer
foggy bc of upwelling
36
deep ocean circulation is a response to ___ | what are the factors creating this
density differences | salinity (high salinity=more dense) and temp (low temp=more dense)
37
deep ocean circulation aka
thermohaline circulation
38
in high latitudes/polar regions, what is the main leading factor for density? why??
salinity bc there is an isothermocline
39
how are deep ocean currents produced
sea ice forms increases salinity of surface water=denser sinks
40
Most water involved in deep-ocean currents begins | so what ocean/continent
high lat | antartica and artic poles' water sinks and goes through the process
41
what happens once the water sinks? | why
temp and salinity stay the same bc not affected by phys porcesses at surface (think of vertical line in deep water zone)
42
where is the edensest water in the world
antarctica
43
describe the movement of deep ocean circulation
sluggish Atlantic--> Indian--> Pacific--> back again
44
when it comess back around, where does it return to and what is the temp of that water
comes back to high lats/poleward as warm currents
45
half of the world lives __ miles from the coast
60
46
what are waves
evidence of energy traveling through water imparted by wind
47
what interface do ocean waves pass through?
interface of hydrosphere and atmosphere
48
waves Derive their energy and motion from
wind
49
what direction do waves move in?
direction of wind
50
crest
top of wave
51
trough
bottom of wave separate waves
52
what is btw wave and crests
water level where water would be w/no waves
53
wave height
distance from crest to trough
54
wave length
distance from crest to crest of anotther wave/distance from one trought to another
55
wave period
time it takes for a crest to pass a specific point
56
what does the wave length, wave height, and wave period depend on
- fetch - time the wind has blown - wind speed
57
fetch
Distance wind traveled across open ocean
58
what happens when the energy imparted increases?
wave height and distance increases
59
how are white caps formed?
waves topple over
60
for a particular wind speed, there is a maximum... | what does this mean in terms of the size of the wave
fetch and duration | will be fully developed (won't increase size)
61
what happens when wind stops, moves direction, ir waves leave storm area
the waves don't move in relation to local wiwnds and form swells
62
Does water move across ocean basins?
no the waveform moves foward (shape of wave)
63
how does water move? | what does this mean about the moevement of water
in a circular oribital motion | returns to same place it started
64
waves move up and down, as well as
forward and backward
65
in deep waters, the water is ____ because there is more than a depth of ___
neglibible 1/2 wavelength
66
what is the depth of half a wavelength aka
wave base
67
as depth increases, the circles get
smaller
68
what happens when a wave reaches shore | describe the depth, CIRCLES
feel bttom depth equAL/Less than 1/2 wavelength | ELLIPTICAL
69
describe the speed and wavelength and waves as they approach shore
slow down wavelengths decrease wave pile up and increase in height breaks at surf zone
70
surf
turbulent water from breakers
71
swash
turbulent water moves up shore
72
backwash
turbulent water moves down slope
73
what are beaches
accumulations of sediment along land margins of lake or ocean
74
where are the sediments of beaches from?
whatever is locally abundant (ex. florida: no mts=shells)
75
what are beach grains mostly dominated by
quaartz grain
76
do materials remain at beaches? what are beache sthen?
no in transit
77
what is perpendicular sand movement
swash and backwash bring sand toward and away from shoreline
78
low wave activity | season
more swash than backwash | summer
79
high energy wave activity | season
more backwash than swash so the beach erodes | winter (storms frewuent and powerful)
80
wave refraction
bending of waves
81
do most waves move toward shore straight on?
no, at angle
82
process of wave refrraction
1. waves reach shallow water offshore from a headland 2. waves slow down while the rest of the wave in deeper water races on ahead 3. deeper water wave ends up closer to shoreline and is parallel to it despite its dif orientation from og orientation
83
wave attack in headlands | bentness energy attack
headlands: waves reach shallow wsooner rso they're bent more nearly parallel to headland and attack from all sides (erosion-mroe energy)
84
wave ttack in bays
refraction causes wave divergence less energy=deposition and accumulation of seidments=beach
85
describe longshore currentv
swash is at an angle back wash is streight down the slope of the beach
86
what is the pattern of transportation for longshore transport
beach drift (zigzag)
87
what are rlonghsore currents
waves that move toward the shore at an angle and produce currents that are parralel to shore
88
what moves more sediment: longgshore currents or beach drift | why
longshore currents | water un surf zone is more turbulent sso cna move fine and coarse grains
89
do longshore currents change direction? why?
yes, waves approach beach in differnt diferections in dif seasons
90
Wave cut cliffs
cutting of land by surf action
91
wave cut platforms
benchlike surfaces from receding cliff as rocks fall into sirf and carried out to sea
92
wave cut terrace
flat uplifted wave cut platform w/ slopes
93
what are the things that will form from the erosional work of refraction
sea caves, sea arches
94
what are sea arches
2 sea caves unites/headland cut by erosion
95
seastack
isolated rock formation like tiny island archh fell in
96
what do longhshore currents produce
beaches, spit, baymouth bars
97
spit
elongated extension of sand from land to bay that hooks landward from thge direction of longhsore current
98
baymouth bar
sandbar cuts off bay from ocean
99
name the erosional feeatures
wave cut cliff, marine terrace, eave cut platform, sea arch, sea stack
100
tombolo
sand conencting mainland to the sea stack or island
101
barrier islands | how do they form
low ridges of sand parallel to shore | spits disconnected from mainland, sea level rise, turbulent wter sand up
102
delta
accumulation of sediment deposited where stream enters
103
estuary
river valley flooded from sea level rise or sibsidence of land,
104
depositional features
sit, baymouth bar, tombolo, barrier islands,

GEO LECTURE (19 decks)

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