Physical Oceanography Flashcards
Absolute Temperature
The measurement of temperature beginning at absolute zero on the Kelvin scale.
Potential Temperature
Temperature that a parcel would attain if adiabatically brought to a standard reference pressure, usually 1,000 hPa.
Conservative Temperature
Thermodynamic property of seawater. It is proportional to the potential enthalpy and is recommended as a replacement for potential temperature as it more accurately represents the heat content.
Absolute Salinity
Mass fraction of total dissolved solids per kilogram of seawater.
Isopycnal
A line connecting points of a specific density or potential density.
Cabbeling
Cabbeling is when two separate water parcels mix to form a third which sinks below both parents. The combined water parcel is denser than the original two water parcels. The two parent water parcels may have the same density, but they have different properties; for instance, different salinities and temperatures.
Thermocline
A thermocline is a thin but distinct layer in a large body of fluid in which temperature changes more drastically with depth than it does in the layers above or below. In the ocean, the thermocline divides the upper mixed layer from the calm deep water below.
Seven Main Water Masses in the world
Antarctic Bottom Water (AABW) North Atlantic Deep Water (NADW) Circumpolar Deep Water (CDW) Antarctic Intermediate Water (AAIW) Subantarctic Mode Water (SAMW) Arctic Intermediate Water (AIW) North Pacific Intermediate Water (NPIW)
Polynya
A stretch of open water surrounded by ice, especially in Arctic seas.
Layers of the atmosphere, from highest to lowest
Thermosphere
Mesosphere
Stratosphere
Troposphere
Three cells
Hadley cells
Ferrel cells (not driven by temperature)
Polar cells
Coriolis effect
An effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation. On the earth, the effect tends to deflect moving objects to the right in the northern hemisphere and to the left in the southern and is important in the formation of cyclonic weather systems.
True/False: International standards such as the ITS-90 are important because they ensure consistency in measurements across time and space; however, strict adherence to these standards is not necessary as they serve as guidelines rather than strict rules.
False
True/False: Conservative temperature and potential temperature are similar in the fact that they are insensitive to pressure.
True
True/False: The chemical approach to measuring the salinity of seawater involves scaling the total dissolved content to a single property using the principle of constant proportions.
True
The practical Salinity Unit is:
The function of temperature, pressure and conductivity; a proxy for true salinity
Defining characteristics of absolute salinity
The chemical approach to measuring the salinity of seawater involves scaling the total dissolved content to a single property using the principle of constant proportions.
Isohaline
Lines of equal salinity on a map of sea surface salinity.
Mediterranean Intermediate Water
Flows out from the Straight of Gibraltar to an approximate depth of 1000m where it sits beneath the less saline Antarctic Intermediate Water
California Intermediate Water
Small volume intermediate water mass mostly the result of coastal upwelling,
Antarctic Intermediate Water
Fills a large portion of ocean, as seen in all ocean basins, and its formation region is marked as the polar front.
Pacific Equatorial Water
Strongly linked to equatorial upwelling and therefore may not occur in El Nino years
Indian Ocean upper waters
Complex upper water mass structure caused, in part, by the monsoons that change the wind patterns twice a year resulting in the reversals in ocean currents
South Atlantic Central water
Unlike in the northern hemisphere, this upper water mass cannot be separated east-west into two parts
Antarctic bottom water
Though to primarily form in the Weddell Sea
Pacific Deep water
Most abundant water mass by volume
Circumpolar deep water
A mixture of North Atlantic deep water, Antarctic bottom water and two intermediate waters in the Pacific.
Nearly all weather occurs in this layer of the atmosphere
Troposphere
Coldest layer of the atmosphere
Mesosphere
Albedo
Reflectivity of the surface
Fill in the blanks: Areas of low pressure are created by __________, while areas of high pressure are created by ___________.
Rising air, Descending air
Positive divergence
A source point where water is being added
Negative divergence
The flow of water decreasing after passing through a point
Lagrangian measurement
Takes measurements with currents/drifters (ex: SVP drifters, CODE drifters)
Eulerian measurement
Takes measurement at a single point (ex: current meters, Acoustic Doppler Current Profiler (ADCP))
Advection
How the movement of a fluid parcel carries properties such as heat and salinity
Acceleration
Refers to how the velocity of a parcel of fluid varies over time.
Factors that contribute to ocean currents
Tides
Thermohaline circulation
Wind
The Coriolis effect
Deflects each layer to the right of the one above creating a pattern called an Ekman spiral
Ekman transport
The net export of water is at a 90 degree angle to the movement of the prevailing wind.
Describe how an acoustic current meter works
A signal is sent from an acoustic transducer. The signal is reflected back to the transducer by suspended particles in the water allowing for the measurement of the current.
True/False: A fundamental assumption of the Acoustic Doppler Current Profiler is that all the suspended particles move at the same velocity as the water.
True
CDT system can measure
Density, Salinity, Sound velocity
Key features of the thermohaline circulation are:
Deep water formation
Spreading of deep waters
Upwelling of deep waters
Near-surface currents
MOC
Meridional overturning circulation
Generating force of waves
Pushes water up across it’s boundary
Restoring force of waves
Pushes water back to boundary
Wave period
(T) seconds, minutes or hours pass between waves
period = #seconds/1 wavelength
Wave speed
wavelength/period
Fetch
Area of the ocean with no obstructions
Constructive Interference
When waves meet IN phase, they will join and create a taller crest
Destructive interference
Waves meet OUT of phase, diminishing the size of the wave
How tall can waves get before they break?
Height must be AT MOST 1/7th as tall as the wavelength is long; wavelength must be AT LEAST 7 times longer than height is tall.
Wave
Rhythmic movement that carries energy through matter or space
Gravity wave
Gravity waves are waves generated in a fluid medium or at the interface between two media (e.g., the atmosphere and the ocean) which has the restoring force of gravity or buoyancy
Rogue waves
Exceptionally large waves that can form when several wave crests all coincide at once.
Semidiurnal
When the two highs and the two lows are about the same height
Mixed Semi-diurnal
If the high and low tides differ in height
Diurnal tides
Occur when there is so much interference by continents, only one high tide and one low tide occur per day.
Tidal consitituent
Harmonic oscillations with periods produced by sun and moon
