Oceanography Exam #2
Salinity of typical seawater is...
3.5% or 35 ppt
In the Southern Hemisphere, a low pressure system spins what directions?
Anticyclonic, left
In the Northern Hemisphere, a high pressure system spins what directions?
Anticyclonic, right
Hurricanes spin __________ in the Northern Hemisphere
Counterclockwise
Concentrated solar radiation at low latitudes because of:
High angle of incidence, small footprint, more direct path
Constructive interference
In-phase waves with about the same wavelengths, wave heights add together
Water freezes its volume __________ by __ %.
Increases, 9%
Cyclones
Indian Ocean
Water interface cause what type of waves?
Internal waves
Two types of covalent bonding
Ionic and Covalent bonds
Hurricane season in Atlantic basin officially defined from _____ to _____________
June 1st to November 30th
Tropical cyclones
Large rotating masses of low pressure characterized by strong winds and torrential rain
Subtropical gyres
Large, circular-moving loops of water driven by the major wind belts. Rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
La Niña (ENSO Cool Phase)
Larger pressure difference across Pacific, intensifies the trade winds, cool water spreads westward toward western Pacific, upwelling intensifies along South America because of intensified winds, heavier rains
Hurricanes gain there energy from what?
Latent heat of condensation
Tropical cyclones develop through a combination of what?
Latent heat of condensation, Coriolis Effect, low pressure, and strong winds
Solar radiation more diffuse at high latitudes because of:
Low angle of incidence, large footprint, must pass through more atmosphere
Mixed surface water properties:
Low density; well-mixed by waves, tides and currents; surface to ~300m
How are waves generated?
Mass movement into water, shifts in the ocean floor, tide, human causes
Rogue Waves
Massive, spontaneous, solitary ocean waves - but rare; difficult to forecast
What is chemical analysis?
Measure amount of chlorine
Radar altimeters
Measure currents on satellites can be used to make dynamic topography maps that show speed and direction of water currents
What does a salinometer do?
Measures water's electrical conductivity (the ability of a substance to transmit an electric current)
Name the three major wind belts in the Northern Hemisphere:
NE trade wind, Westerlies, Polar Easterlies
Principal of Constant Proportions
No matter what the salinity the fraction of the salt that is chloride remains the same. Chloride is 55.04% and salt is 30.61%. The same is true for the other components.
List the 5 subtropical gyres:
North Atlantic gyre, South Atlantic Gyre, North Pacific Gyre, South Pacific Gyre, Indian Ocean Gyre.
Hurricanes
North and South America
Surface currents
Occur within and above the pycnocline to a depth of 1 km (10% ocean volume). Develop as a result of friction between the ocean and the wind blowing over its surface
Air - ocean interface cause what type of waves?
Ocean waves
Marine effect
Oceans moderate temperature changes from day to night and during different seasons
Sort these reservoirs from largest to smallest percentage of the water on Earth: Water vapor in atmosphere, oceans, streams and lakes and rivers, ground water and soil moisture, frozen glaciers and ice caps
Oceans, Frozen in Glaciers and Ice Caps, Groundwater and Soil Moisture, Streams, lakes & rivers, Water Vapor in the Atmosphere
Destructive interference
Out-of-phase waves with about the same wavelengths, waves can cancel each other out
What decreases salinity?
Precipitation, melting icebergs, runoff, melting seaice
Upper water properties:
Pycnocline, thermocline, and halocline if at lower latitudes, Barrier to vertical mixing and migration of sealife, ~300m to 1000m
Wave steepness
Ratio of wave height (H) to wavelength (L)
Convection cells
Rising and sinking air moving in a circular motion.
How do tropical cyclones form?
Rising warm air causing thunderstorms, an area of very low pressure and the storms rotate accelerating up forming the tropical cyclone
Name the three major wind belts in the Southern Hemisphere
SE trade wind, Westerlies, Polar easterlies
How would the wind belts be different if there was no Coriolis effect?
The wind would not deflect at all and rather be a straight flow from high to low pressure
Doppler flow meters
Transmit low frequency sound into the water and the shift in frequency of sound backscattered from particles in the water column can be used to determine current direct and velocity.
Waves transport what?
Transport energy
Ocean currents transport what?
Transport water
Mixed interference
Two wave groups with different wavelengths and different wave heights
In the northern hemisphere, if the wind blows from south to the north along the east coast of continent, along the coast there will be...
Upwelling
Tilt Current Meter (TCM)
Uses angle of stick to determine how fast current is moving
Downwelling
Vertical movement of water to deeper parts of the ocean. Usually associated with low primary productivity. Important as carries oxygen from surface water to the deep.
Upwelling
Vertical movement of water to the surface. Water usually cold, rich in nutrients. Consequently get high primary productivity.
Pacific warm pool
Water warms as moves flows in the equatorial region, creating a warm wedge of water on western side of the Pacific called the Pacific Warm Pool.
Typhoons
Western North Pacific
Tropical Storm
Winds 61-120 km/hour (38-74 miles/hour)
Hurricane or tropical cyclone
Winds above 120 km/hour (74 miles/hour)
Tropical Depression
Winds less than 61 km/hour (38 miles/hour)
Pycnocline
a layer of water in which there is a rapid change of density with depth
Thermocline
abrupt change of temperature with depth
Surface currents
affected by the movement of air, particularly wind belts, over the surface of the ocean. Run near surface and are horizontal currents. Wind driven.
Horse latitudes
are regions of high pressure and gentle winds at about 30 degrees north and south latitude
Describe orbital progressive waves
around and around; waves on ocean surface; combination of longitudinal and transverse waves
Describe longitudinal progressive waves
back and forth; compress and decompress as they travel, like a coiled spring
Thermohaline Circulation
density differences that cause deep circulation caused by temperature and salinity
Halocline
depth where there is a rapid change in salinity
Ekman spiral
describes the speed and direction of flow of surface waters at various depths in relation to wind blowing over the surface
The Water Molecule
dipolar (H is +, O is -), polarity, bent structure
Diverge in bays = energy is _______ in bays
dissipated
Subtropical highs
high pressure zones descending air at latitudes of 30º north and south
Polar highs
high pressure zones of descending air at the poles.
Air flows from _____ to ______ pressure
high to low pressure, leads to the formation of circulation cells
Crest
highest points of a wave
Wave length (L)
horizontal distance from crest to crest or trough to trough
Deep currents
temperature and salinity changes at surface cause high-density water to form, which sinks. Dense water spreads beneath the surface, causing deep currents. These currents have vertical motion. Density driven.
Evaporation latitudes are closest to:
the equator
Land breeze
the flow of air from land to a body of water
Salinity is the ratio of...
the mass of dissolved substances to the mass of the water sample
Polar front
The boundary at which air flowing away from the polar regions collides with the warmer air from the lower latitudes, 60 degrees latitudes
Coriolis effect
The effect of Earth's rotation on the direction of winds and currents.
Sea breeze
The flow of cooler air from over an ocean or lake toward land
As a deep-water wave becomes a shallow-water wave:
- Wave speed decreases - Wavelength decreases - Wave height increases - Wave steepness (height/wavelength) increases - When steepness > 1/7, wave breaks
Tropic of Cancer
23.5 degrees N; Receives greatest amount of annual solar radiation
Tropic of Capricorn
23.5 degrees S; Receives greatest amount of annual solar radiation
Hadley Cell
0 to 30 degrees. Heat rises at equator, carried away and sinks at 30 degrees.
Pure water density is....
1 g/cm^3
Each subtropical gyre is composed of four main currents that flow into one another, which are:
1. Equatorial 2. Western Boundary 3. Northern or Southern Boundary 4. Eastern Boundary
Seawater density is...
1.028 g/cm3
Three types of progressive waves:
1.Longitudinal 2.Transverse 3.Orbital
Wave base
1/2 L
If wave steepness exceeds ____ the wave will break
1/7
Ferrel Cell
30 to 60 degrees. Air at 30 degrees stable so moves towards the poles towards unstable air, or subpolar lows
Where are the westerlies?
30-60 degrees latitude
Open-ocean salinity ranges from what?
33-38 ppt
greatest density of water occurs at what temperature?
4 degrees celsius, explains why ice floats
U.S. Navy Hydrographic Office published a report in early 1900s which said that the theoretical maximum height for a wind driven wave is _____.
60 feet
Polar Cell
60 to 90 degrees. Air rises at 60 degrees and moves towards the poles, smallest and weakest
Where are the polar easterlies?
60-90 degrees
Over __ chemical elements can be found in seawater
80
Deep ocean currents affect about __% of the world's ocean water.
90%
How do you change salinity?
Add/remove water, add/remove dissolved substances
Internal Waves
Associated with pycnocline, larger than surface waves (can be 100+ m), caused by tides, turbidity currents, winds, ships
Where is there no Coriolis Effect?
At the equator
Doldrums or Intertropical Convergence Zone (ITCZ)
At the equator, where the trade winds come together causing air to rise
Highest Coriolis effect occurs where?
At the poles
Low angle of incidence
At the poles, more reflection of incoming light
High angle of incidence
At the tropics, less reflection of incoming light
Residence time
Average length of time a substance remains dissolved in seawater
High pressure, sinking air causes what weather?
Clear fair, dry weather (South America)
Hurricanes spin __________ in the Southern Hemisphere
Clockwise
Low pressure, rising air causes what weather?
Cloudy, rain (Indonesia/Australia)
In what area will salinity vary more widely?
Coastal regions
Deep water properties:
Cold high density water involved in deep current movement, below ~1000m
Interference Patterns
Collision of two or more wave systems, interfering with one another
El Niño-Southern Oscillation (ENSO)
Combined oceanic and atmospheric effects that periodically alternate the Pacific between warm and cold phases. Affects ocean temperatures, circulation, weather patterns, winds. Can have dire consequences on marine life. Around Christmas time.
What factors determines the direction the wind belts blow?
Coriolis Effect, rotation, High to Low pressure change
In the Southern Hemisphere, a high pressure system spins what directions?
Cyclonic, left
In the Northern Hemisphere, a low pressure system spins what directions?
Cyclonic, right
Equatorial upwelling
Divergence of surface currents along the geographical equator and upwelling of cold, nutrient rich water. Common in Pacific and creates areas of high productivity and rich fishing grounds.
What causes seasons?
Earth's tilt of 23.5 degrees; effects amount of solar energy received at different locations and times
Hurricanes move _____ to _____ as driven by trade winds
East to West
Ekman transport is...
Ekman transport is 90º to the right of the wind direction in the Northern Hemisphere and 90º to the left in the Southern Hemisphere.
Waves are _____ in motion.
Energy
______ is transmitted by waves?
Energy
Hurricanes do not occur where?
Equator
How can you measure salinity?
Evaporation, salinometer, chemical analysis,
Equatorial currents
Flow westward, parallel to the equator.
Factors effect the idealized pattern of atmospheric circulation
Seasons, lower heat capacity of continental rock compared to the ocean, uneven distribution of continents and ocean across the earth's surface
Progressive waves
Simple uniform-motion waves that travel without breaking
High latitudes
Surface and deep waters cold year-round. No thermocline, isothermal (same heat)
Low latitudes
Surface waters warmed by high Sun angle, warm surface mixed layer to 300m because of mixing mechanisms like currents, waves, tides
El Niño (ENSO Warm Phase)
Switches east-west weather pattern in Pacific, so now South America gets rain, and West Pacific is dry. Changes water temperature, warm water reduces the impact of upwelling, so primary productivity diminishes, increases eastern Pacific hurricanes
What has strongest control of density changes?
Temperature
Winds blowing out of the north towards the south in the Southern hemisphere will appear to...
be reflected towards the east
Refraction
bending of each wave crest as it approaches the shore
Northern or Southern Boundary Currents
between 30 and 60º latitude the prevailing westerlies direct water in an easterly direction across an ocean basin
Where are the trade winds?
between equator and 30 degrees
Covalent Bonding
bonds formed from interaction of two or more atoms
Subtropical convergence
buildup of water in the middle of the gyre from Ekman transport
Steam burns us because of...
condensation
Eastern boundary currents
currents are turned by the Coriolis effect and land barriers towards the equator; carry cool water from high latitudes towards equator
As depth increases, current speed _______
decreases
As temperature increases, seawater density _________
decreases
Water vapor ______ the density of air as water vapor has a lower density than dry air
decreases
Density increases as temperature _________
decreases (ex:warm air rises and cold air sinks)
If water depth is greater than wave base (>½L), wave is a ________________.
deep water wave
Currents are driven by....
density and wind
Highest salinity at _______
equator
Highest temperature at _______
equator
Lowest density at the _______
equator
What increases salinity?
evaporation, formation of sea ice
Waves at the surface of the ocean...
have aspects of both longitudinal and transverse waves, water molecules move in an orbital path, occur between the boundary of two fluids of different densities
high salinity = ________ density
high
Descending columns of cool air produce _____ pressure
high pressure
Sinking cool, air creates an area of _________
high pressure
As pressure increases, seawater density _________
increases
As salinity increases, seawater density ________
increases
Continental effect
land areas have greater range of temperatures from day to night and during different seasons
Coriolis effect deflects wind to the _____ in Southern Hemisphere
left
Water is most dense while it is in what state?
liquid
Ions with ____ residence time are in high concentration in seawater
long (chloride and sodium)
Cloudy weather and lots of precipitation under _____ pressure
low pressure
Rising columns of low density, warm air produce ____ pressure
low pressure
Rising warm, air creates an area of ____________
low pressure
The equator is ______ pressure
low pressure
Equatorial low
low pressure zones due to rising air
Subpolar low
low pressure zones due to rising air at latitudes of 60º north and south
Oceans and atmosphere transfer excess heat from ____ to _____ latitudes
low; high
Troposphere
lower portion of the atmosphere, which extends to an altitude of about 12 km; all weather produced here
Seawater freezes at a _______ temperature (_____) than freshwater (0°C)
lower, -1.8 degrees celsius
Trough
lowest point of a wave
Converge on headlands = ______ energy released, better for surfing
more
Warm air holds ____ water vapor than cold air
more
Western boundary currents
occur when an equatorial currents meets the land on the western side of an ocean basin, carry warm water from the equator to higher latitudes, Coriolis effect deflects currents away from equator
Albedo
percent of incident light that is reflected back in space, average albedo of Earth is ~30%
Brackish
produced in areas where freshwater (from rivers and rainfall) and seawater mix
Hypersaline
produced in areas with high evaporation rates and limited open-ocean circulation (Ex:Dead Sea, Red Sea, Great Salt Lake City)
Seawater has similar properties to...
pure water
Coriolis effect deflects wind to the _____ in Northern Hemisphere
right
Warm air _____
rises
Ions with ____ residence time are in low concentration in seawater
short (calcium)
Thermal contraction
shrinkage of most substances caused by cold temperatures, occurs from 0-4 degrees celsius, density decreases
Cool air _____
sinks
The density of seawater is controlled by...
temperature, salinity, and pressure
Frequency (f)
the number of wave crests passing a fixed position per unit time; 1/T; inverse of wave period
Precipitation latitudes are closest to:
the poles
Global Thermostatic Effects
thermostatic effects of water moderate changes in temperature and drive Earth's climate
Wave period (T)
time it takes for one complete wave (i.e. one wavelength) to pass a fixed position.
Ionic bonds form between sodium and chloride atoms as a result of the...
transfer of electrons between atoms
Covalent bonding
type of bond in which 2 or more nonmetal atoms share electrons
Ionic bonding
type of bond in which a metal and nonmetal transfer electrons (produces ions)
Describe transverse progressive waves
up and down; side-to-side waves; transmit through solids, not liquids
If direction of the winds reverse then may swap from a situation of...
upwelling to downwelling or vice versa.
Sweat cools us because of...
vaporization
Wave height (H)
vertical distance between crest and trough
Shoaling water
water becoming gradually more shallow
The speed of a deep-water wave is proportional to...
wavelength
Steady state
when addition rate = removal rate
Currents usually follow same pattern as the _______
wind belts
Surface ocean currents are driven primarily by ________ and modified by ________.
wind; the Coriolis effect and land
Surf zone
zone of breaking waves near shore
