1. TYPICAL TEMPERATURE PROFILES

1. 1. TYPICAL TEMPERATURE PROFILES Thermocline is a range of depths (from Pinet, 1998)

2. thermistor 2. CTD – Conductivity-Temperature-Depth Recorder

3. (from Pinet, 1998) 3. Celsius Temperature = Thermodynamic Temperature – 273.15ºK Measured with ITS90 T68 = 1.00024 T90

4. (NORTHERN HEMISPHERE) (from Pinet, 1998) 4

5. (NORTHERN HEMISPHERE) (from Pinet, 1998) 4

6. 5. Seasonal variability of sea surface temperature throughout the ocean

7. PRESSURE Pressure = Force / Area Pressure = Mass * Gravity / Area Mass = Density * Volume Pressure = Density * Volume * Gravity / Area Volume/ Area = Depth Pressure = Density * Gravity * Depth

8. 6. PRESSURE Mixed Layer Pycno- cline z1 z2 z z3 - z Pz - z - z Pz Pz DENSITY VARIES CONINUOUSLY WITH DEPTH DENSITY CONSTANT DENSITY STRATIFIED Pz = -Σ13ng zn Pz = - g z Units: N/m2 = Pa 1 m depth ~ 1 db ~ 104 Pa

9. SALINITY Old Definition: “The salinity of a sample of sea water represents the total mass of solid material dissolved in a sample of sea water divided by the mass of the sample, after all the carbonates have been converted into oxide, the bromine and iodine replaced by chlorine, and all organic matter completely oxidized.” Absolute Salinity: “ratio of the mass of dissolved material in sea water to the mass of sea water.” ----- can not be measured in practice. Practical Salinity: is defined in terms of the ratio Electrical conductivity of a sea water sample at 15ºC and one standard atmosphere……. = K15 Conductivity of a KCl solution in which the mass fraction of KCl is 0.0324356 at same T and P If K15 = 1, then the Practical Salinity is 35

10. S = a0 + a1 K15½ + a2 K15 + a3 K153/2 + a4 K152 + a5 K155/2 a0 = 0.0080 a1 = -0.1692 a2 = 25.3851 a3 = 14.0941 a4 = -7.0261 a5 = 2.7080 Σai = 35.000 where: Good for 2 < S < 42

11. Major Constituents The concentrations of these major constituents are conservative. They are unaffected by most biological and chemical processes. This is related to the principle of constant proportion Cl- 18.98/34.4 = 55% Na+ 10.556/34.4 = 31%

12. Residence Time = Concentration (mass/vol)/Rate of supply (mass/vol/time)

13. Where do the Salts come from?

14. high temperate subtropical 7. (from Pinet, 1998)

15. 8.

16. (from the Navy Coastal Ocean Model)

17. (Pinet, 1998) 9. Latitudinal variations in surface salinity High evaporation in subtropics (wind and heat) causes high surface salinity What would temperature look like?

18. Salinity 37 30 34 20 Temperature 31 10 TEMPERATURE

19. Density Anomaly σt = Density - 1000 Specific Volume = Inverse of Density 10. WATER DENSITY density anomaly (kg/m3) 23 24 25 26 27 Equator Density Profiles in the Open Ocean Tropics 1000 depth (m) 2000 High Latitude 3000 4000

20. 11. (from Pinet, 1998)

21. Equation of State (EOS-80) A through N are polynomials T is temperature in oC S salinity P pressure in bars K is the secant bulk modulus (change in volume as pressure is changed) Determines water density from T, S, and P

22. Specific Volume Anomaly Check values:

23. Seawater freezes before reaching max density -1.33 24.7 12. Effects of Salinity on the Properties of Seawater Lowers freezing point Lowers temperature of maximum density Lowers evaporation rate A lake turns over as it freezes The ocean remains stratified as it freezes (from Pinet, 1998)

24. 13. 90 % of Ocean Water Mean T & S for World Ocean Greater influence of salinity on density

25. 14. Effects of Temperature and Salinity on Density x 10-4 oC-1 x 10-4 S-1 Saline Contraction Thermal Expansion Density changes by 0.2 kg/m3 for a T change of 1oC, and by 0.8 kg/m3 for a S change of 1.

26. Potential Temperature  In situ and Potential Temperature in the Mindanao Trench (from Millero’s home page) Temperature a water parcel would have if raised adiabatically to the surface

27. 15. Example of in-situ and potential temperature σt σΘ 27.4 27.8 27.4 27.8 T Θ 0 1 2 3 4 0 1 2 3 4 2000 2000 depth (m) depth (m) 4000 4000 6000 6000 σt σΘ T Θ 8000 8000 10000 10000 How do we convert to potential temperature?

28. Data off Antarctica ~0.1º change at 1000 m in-situ potential ~0.3º change at 3000 m Effect of pressure on density Γ is the adiabatic lapse rate Γ can also be obtained from Unesco Technical Papers in Marine Science # 44 by Fofonoff and Millard, Unesco 1983

29. Density Ratio Relative importance of thermal expansion and haline contraction. Tells us whether temperature or salinity gradient is most important in stratification

30. Example in Easter Island

31. SOUND SPEED Sound is a wave that travels efficiently in water at a speed given by this Thermodynamic expression. Eta is the entropy (normalized energy of the system) A simpler form of that equation is: C = 1449 + 4.6 T – 0.055 T 2 + 1.4 (S – 35) + 0.017 D (m/s)

32. 16. C = 1449 + 4.6 T – 0.055 T 2 + 1.4 (S – 35) + 0.017 D (m/s) Cair = 330 m/s ~ 660 kn

34. SOFAR Channel and Acoustic Shadow Zone (SOund Fixing And Ranging ) Depth (m) (From Tomczak’s Web Site)

35. turbid coastal water k = 2 clear ocean water k = 0.2 k = 0.02 Light Penetration in Sea Water Iz = Io e –k z k = vertical attenuation coefficient (m-1) (fraction of that entering at the surface)