Hydrography correct answers density dependent on temperature and salinity
Compare horizontal and vertical currents correct answers Horizontal currents are typically stronger than vertical. Most currents flow horizontally, while vertical movement is very localized.
Describe the Geoid correct a...
Oceanography || with 100% Correct Answers.
Hydrography correct answers density dependent on temperature and salinity
Compare horizontal and vertical currents correct answers Horizontal currents are typically
stronger than vertical. Most currents flow horizontally, while vertical movement is very
localized.
Describe the Geoid correct answers The Geoid is the shape that the surface of oceans would take
under the influence of earth's gravity and rotation alone, in absence of winds and tides. It is the
ocean surface at rest and mirrors the ocean bottom 1/200. Surface elevation or topography is
deviation from the geoid.
Surface tilt determines the strength of: correct answers geostrophic currents. Geostrophic
currents are the horizontal movement of surface water arising from a balance between pressure
gradient force and coriolis force.
The oceans have a large _____ ___________ which exerts a significant and controlling effect on
the earth's climate. correct answers heat capacity. Salt content and pressure lowers specific heat
capacity by creating additional electronic bonds which INCREASE density, DECREASE
freezing point and max density temperature.
Describe physical ocean phenomena timescales correct answers Most ocean phenomena with
short spacial scales have short time scales, and long with long. There are some exceptions such
as tides and tsunamis. Large scale phenomena are more effected by earths rotation.
What are marginal seas? correct answers Large basins of saltwater connected to the open ocean.
The water molecule is polar. Why does this property give water a high latent heat of
evaporation? correct answers The water molecule is polar, meaning it is positively charged on
the hydrogen side and negatively charged on the oxygen side. The molecules bond to each other
with electrical forces called hydrogen bonds. A lot of energy is needed to break these bonds.
Water molecules are able to dissolve salt into ions and conduct electricity (lowers freezing temp,
max density temp, increases density). Cool water will sink before freezing, unless there is a layer
of fresh water on top.
What is pressure? correct answers Pressure is a force acting on a unit surface. In the ocean, the
origin of the force is gravity, and the magnitude is the weight of the water column and
atmosphere above a horizontal surface. Hydrostatic pressure is the weight of a water molecule
above depth (not including atmosphere). Decreases volume, increases density and temperature
What is temperature? correct answers Temperature is a measure of disordered microscopic
movement of molecules, thus a form of kinetic energy.
,What is compressibility? correct answers Increasing pressure that decreases the volume of a
water parcel, increasing the temperature about 0.1 degrees C for every 1000m moved downward.
What is an adiabatic process? correct answers A process that goes on without heat exchange to
mixing with surroundings.
What is potential temperature? correct answers The temperature a parcel of water will be if
moved adiabatically to the sea surface. Always lower than measured temperature except at sea
surface where they are the same.
Thermocline correct answers The layer in the ocean where temperature changes rapidly with
depth.
Surface temperature on East vs. West coast correct answers Surface temperature on Western
sides of continents are cooler due to coastal upwelling and trade winds that blow water off the
surface and cause upwelling
Equation for pressure correct answers P=pgh (bar, dbar or atm)
p=density (m/v) in kg/m3
h=water column height in m
g=gravity acceleration m/s2
Adiabatic Lapse Rate correct answers Temperature change per unit pressure change due to the
compression of the volume. When parcels are moved adiabatically (no heat exchange to
surroundings)
What is the difference between absolute salinity and practical salinity? correct answers Absolute
salinity is the mass of all dissolved matter in seawater. Practical salinity is calculated from
measured electric conductivity, only matter accounted for is ions.
What processes change ocean salinity? correct answers Evaporation and sea ice freezing can
INCREASE salinity. Precipitation, river runoff, and melting ice can DECREASE salinity.
Halocline correct answers A layer where salinity changes rapidly with depth
Why is the Pacific Ocean less saline than the Atlantic? correct answers Net evaporation in the
Atlantic adds water vapour into the atmosphere, trade winds bring it to the Pacific where net
precipitation returns it to the ocean.
What is a tracer and how are they useful? correct answers A tracer is any compound that can be
used to trace pathways of ocean circulation, or age of a water parcel( time since water particle at
surface).
What is the difference between a conservative and non-conservative tracer? Give 2 examples.
correct answers In the interior of the ocean, conservative tracers only change due to mixing with
, surrounding water (Potential temperature, salinity, CFC's) Non-conservative tracers change also
due to biological, chemical or radioactive processes (oxygen, nitrate).
Describe some properties of saltwater correct answers Saltwater has a lower heat capacity than
fresh water. The freezing temperature of saltwater is approx. -1.9 degrees C. Density of saltwater
is highest at the freezing point.
In cold temperatures, freezing temperature water is less_______, so it stays at the surface
protecting ice from melting. correct answers dense
How does the density of seawater depend on temperature, salinity and pressure? correct answers
Density INCREASES when temperature decreases and when salinity and/or pressure increase.
Explain stratification, pycnocline and stability. correct answers Stratification: is the distribution
of density with depth, excluding the pressure effect. The water column is stratified with
increasing potential density with depth due to the buoyancy effect
Pycnocline: is the depth range where density increases rapidly with depth
Stability: If density of a water column changes more with depth than pure compression effect
will lead to, water column is stable (when potential density increases with depth= stable. When
potential density constant=neutral. When potential density decreases with depth=unstable (will
overturn)
What is the thermobaric effect? correct answers A cold water parcel is more compressible than a
warm water mass, and density of a cold water parcel will increase more with depth than a warm
water parcel if they both sink
What is potential density? correct answers With potential temperature and reference pressure at
surface, parcels from each depth moved adiabatically. Potential density and neutral density are
two approximate measures where pressure effect is almost removed.
Buoyancy force on vertically displaced water column is the difference between correct answers
its weight and upward directed force estimated from Archimedes principle.
Archimedes principle correct answers states any object immersed in fluid is buoyed up by a force
equal to the weight of the fluid displaced by the object. If the lift force on a water parcel is
different from the weight of the parcel, the parcel has potential energy that will make it start
moving to where the two forces are equal. Will often overshoot and oscillate (internal gravity
wave).
Brunt-Vaisala Frequency correct answers The buoyancy frequency or frequency of internal
gravity waves caused by a parcel that overshoots and begins to oscillate. If the water is more
stratified, oscillation will be faster. Shortest period(fastest oscillation)= strongest stratification.
Adiabatic compression has 2 effects on water parcels correct answers 1. Increases temperature
2. Mechanically compresses so that molecules are closer together which decreases volume and
increases density
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