Atmospheric & Oceanic Sciences Final Flashcards
Define the ocean
Vast body of saline water that occupies the depressions of earths surface
Name the 5 oceans
- Southern Ocean
- Atlantic Ocean
- Pacific Ocean
- Indian Ocean
- Arctic ocean
What percent of earths surface is water?
what percent of earths surface is land?
71% Ocean
29% land
What is the ratio of Ocean to Land in Northern hemisphere & southern hemisphere ?
Northern Hemisphere–> 1.5:1
Southern hemisphere–> 4:1
97 % of earths water is found in…
the ocean
2.5% of earths water is found in….
Land ice, ground water, Lakes & rivers
Percentage of ocean area for Pacific, Atlantic & indian ocean
Pacific–> 46%
Atlantic–> 23%
Indian–> 20%
What is the average ocean depth & the max ocean depth
Average: 3,682m
Max: 11,000m (at mariana trench)
What is Salinity ?
The concentration of dissolved solids in seawater (g/kg or ppt)
What is the average seawater salinity
3.5% OR 35 grams of salt per kg (later) of seawater
Which is more dense; cold salty water or warm less salty water ?
Cold Salty Water
Why is seawater 2% - 3% heavier than pure water?
its due to the dissolved salts, density of seawater is between 1.02 - 1.03 g/cm cubed which is > 1.00g/cm cubed of pure water
How is the ocean stratified (arranged) and what does it depend on ?
Ocean is stratified by density, which is due to Temperature & salinity
How does Seawaters density INCREASE?
increases by the increase of salinity & pressure AND decreasing temperature
TRUE OR FALSE:
2 or more seawater samples can have the same density with different combination of temperature & salinity
TRUE
What is the principle of Constant Proportions?
Although the salinity of the seawater may vary with location, the ratio of dissolved solids (% of salts) remains constant
What goes in, must come out….
the ocean is in chemical equilibrium
How is salinity calculated?
its calculated by using seawaters conductivity, which depends on concentration, mobility of ions & water temperature
why is heating the seawater & measuring the residual salts not a good way to calculate salinity ?
because in certain types of salts water molecules do not evaporate completely & some of them do.
What is a salinometer ?
device that measures the salinity by passing electric current through a mass of water, measuring its conductivity then converts it to salinity
What are the 3 zones of Stratification ?
- Surface/mixed Layer
- Pycnocline Layer
- Deep Layer
Characteristics of the surface/mixed layer Zone
Well mixed layer
LEAST dense
Temperature & salinity constant due to waves & currents
depth –> varies from 150m - 1000m
Characteristics of Pycnocline layer zone
pycnocline meaning strong slope
temperature DECREASES rapidly with depth
density INCREASES with depth due to decrease in temp
What is the thermocline (in pycnocline layer)
major factor to form the pycnocline layer
mainly forms in the mid to low latitude
LOW SALINITY (precipitation > evaporation)
What is the Halocline (in pycnocline layer)
factor that produces (along with thermocline) a pronounced pycnocline
High precipitation region or river-runoff mixes with coastal region, salinity rapidly changes
Characteristics of Deep Zone Layer
Below 1,000m in mid latitude
very cold water (-1 to -3 degree C)
very little change in density
contains about 80% of ocean water
What are colligative properties ?
properties of a solution, depend on concentration, the more concentration the stronger the impact
How are heat capacity & salinity related
as salinity increases, heat capacity decreases
BECAUSE: less amount of heat is required to raise the temperature of seawater by 1 degree than freshwater.
How are freezing point & salinity related
as salinity increases, freezing point decreases
BECAUSE: salts act as an antifreeze, sea ice forms at lower temp
How are Evaporation and salinity related
as salinity increases, evaporation decreases as dissolved salts attract water molecules
How are osmotic pressure & salinity related
as salinity increases osmotic pressure increases
does cold/hot water hold more gas in solution ?
COLD
which is the most abundant gas in seawater (& percentage)
Nitrogen–> 48%
what percentage of oxygen is present in seawater & how much is dissolved in 1 L
36%
6mg of oxygen is dissolved in 1L
what Percentage is CO2
15%
very soluble in water
forms carbonic acid, bicarbonate & carbonate with water
what do marine organisms use calcium carbonate for?
to build shells & skeletons & form sediments & limestone rocks when they die
TRUE/FALSE
CO2 moves quickly from the atmosphere to the ocean & slowly from the ocean to the atmosphere
TRUE
sediments dissolve & re-form CO2 & can enter the atmosphere
Why is there an abundance of oxygen at the surface of the seawater?
due to photosynthesis
What causes the oxygen to decrease when the depth increases
due to respiration
Whats the ph of seawater at the surface & deep layer and why
Surface: pH is high due to warmer water & photosynthesis
Deep layer: pH is lower due to more CO2 (from respiration & decay of dead matter) & no photosynthesis
what drives ocean circulations ?
winds & differences in water density
What two factors distribute tropical heat world wide?
ocean currents & winds
Two types of currents
- Surface currents
2. Thermohaline currents
Define Surface currents
movements driven by wind friction of water near surface
water flows horizontally in the upper 400m.
happens above pycnocline layer
Define Thermohaline currents
slow deep currents that affect the seawater circulation
how much of the oceans water is influenced by surface currents? & what is the primary force driving them
10%
wind
define Gyre
periphery of ocean basins which the surface currents flow around
how does water move in the northern & southern hemisphere gyres
Northern hemisphere gyre: clockwise
Southern hemisphere gyre: counterclockwise
in what direction does surface water layer move in northern & southern hemisphere & at what angle ?
BOTH 45 degree angle
Northern hemisphere: RIGHT
Southern hem: LEFT
