Laurie211098
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Seawater density is often reported in σ. Densities reported this way show the deviation from pure water in kg/m3. Therefore a seawater density of 25 σ indicates an actual density of 1025 kg/m3. This is done so the important density changes are easier to visualise.
The general form of the density equation is
σ = a +bT + cS +dT2 +eST + fS2 + gT3 + hST2 + iS2T + jS3
Where σ is the density, S is salinity (in psu) and T is temperature (in °C).
The polynomial coefficients ‘a to j’ are given below as calculated by Cox et al. (1970).
a = 8.00969062 x 10-2
b = 5.88194023 x 10-2
c = 7.97018644 x 10-1
d = -8.11465413 x 10-3
e = -3.25310441 x 10-3
f = 1.31710842 x 10-4
g = 4.76600414 x 10-5
h = 3.89187483 x 10-5
i = 2.87971530 x 10-6
j = -6.11831499 x 10-8
Table 1
What is the density of water in the Gulf Stream (in σ)?
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What is the density of water in the North Atlantic Drift (in σ)?
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What is the density of water in the Greenland Sea (in σ)?
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What is the density of AABW (in σ)?
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What is the density of NADW in σ ?
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There is observational error on the temperatures and salinities shown above - so the densities you have computed may not be physically plausible. Does your knowledge of physical geography mean that dense water formed in the North Atlantic must flow above that of dense water formed around Antarctic.
True or false?
Question 17
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Heat Capacity (Cp) is the thermal energy it takes to raise 1 kilogram of a substance by 1°C. Seawater has a very high Heat Capacity of 3.993 kJ kg−1 K−1. Assume the Gulf Stream is 80 Sv (106 m3/s) and as it travel across the North Atlantic Ocean to the Greenland Sea the surface 10% cools by 10˚C. Calculate to three significant figures how much energy the Gulf Stream releases per day as it cools (in kJ). Assume that one litre of seawater weighs one kg and remember there are a 1000 litres in one m3.
Select one:
a. 1.15e12
b. 7.67e13
c. 2.76e7
d. 3.19e11
e. 2.76e16
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Estimate to two significant figures how many coal fire stations generate the same amount of heat released over Europe by the cooling of the Gulf Stream. Assume a standard 500 MW coal fire power station generates 4.32 x 1010 KJ per day.
Answer:
The general form of the density equation is
σ = a +bT + cS +dT2 +eST + fS2 + gT3 + hST2 + iS2T + jS3
Where σ is the density, S is salinity (in psu) and T is temperature (in °C).
The polynomial coefficients ‘a to j’ are given below as calculated by Cox et al. (1970).
a = 8.00969062 x 10-2
b = 5.88194023 x 10-2
c = 7.97018644 x 10-1
d = -8.11465413 x 10-3
e = -3.25310441 x 10-3
f = 1.31710842 x 10-4
g = 4.76600414 x 10-5
h = 3.89187483 x 10-5
i = 2.87971530 x 10-6
j = -6.11831499 x 10-8
Table 1
Location | Water Temperature (°C) | Water Salinity (psu) |
Gulf Stream | 27.94 | 35.89 |
North Atlantic Drift | 17.83 | 35.27 |
Greenland Sea | 8.24 | 34.78 |
NADW | 4.34 | 34.88 |
AABW | 0.17 | 34.77 |
What is the density of water in the Gulf Stream (in σ)?
Answer:
Question 12
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What is the density of water in the North Atlantic Drift (in σ)?
Answer:
Question 13
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What is the density of water in the Greenland Sea (in σ)?
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Question 14
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What is the density of AABW (in σ)?
Answer:
Question 15
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What is the density of NADW in σ ?
Answer:
Question 16
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There is observational error on the temperatures and salinities shown above - so the densities you have computed may not be physically plausible. Does your knowledge of physical geography mean that dense water formed in the North Atlantic must flow above that of dense water formed around Antarctic.
True or false?
Question 17
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Question text
Heat Capacity (Cp) is the thermal energy it takes to raise 1 kilogram of a substance by 1°C. Seawater has a very high Heat Capacity of 3.993 kJ kg−1 K−1. Assume the Gulf Stream is 80 Sv (106 m3/s) and as it travel across the North Atlantic Ocean to the Greenland Sea the surface 10% cools by 10˚C. Calculate to three significant figures how much energy the Gulf Stream releases per day as it cools (in kJ). Assume that one litre of seawater weighs one kg and remember there are a 1000 litres in one m3.
Select one:
a. 1.15e12
b. 7.67e13
c. 2.76e7
d. 3.19e11
e. 2.76e16
Question 18
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Marked out of 4.00
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Question text
Estimate to two significant figures how many coal fire stations generate the same amount of heat released over Europe by the cooling of the Gulf Stream. Assume a standard 500 MW coal fire power station generates 4.32 x 1010 KJ per day.
Answer: