OCN 5401

OCN 5401

Chapter 8

Distribution of Temperature and Salinity

Instructor: Dr. George A. Maul

[email protected] / X 7453

Map of Hecataeus of Miletus (ca. 550 BC – 476 BC) a student of Greek geographer Anaximander (ca. 610 BC – 546 BC), a student of Thales of Miletus (ca. 624 BC – 546 BC).

Why do these sea surfacesalinities vary?

E-(P+R)

http://precip.gsfc.nasa.gov/

Global Precipitation Climatology Project

Meridional Distribution of Salinityhttp://salt-oceans.tumblr.com/post/52388590815/a-pinch-of-salt-in-the-deep-blue-sea

Sea surface temperatures (SST) in the world ocean during August

Why do these sea surface temperatures vary?

Sea Surface Density

A16 Temperature Section

𝜃=𝑇 −𝑇 𝛽 𝑔𝐽 𝐶𝑝

𝑑𝑧

Water mass formation in the Southern Ocean

Water Mass Formation in theSouthern Ocean

con’d

Water mass formation in the Arctic Ocean

Fram Strait

Temperature-Salinity(T-S) Diagram

𝐴𝑑𝑣𝑒𝑐𝑡𝑖𝑜𝑛−𝐷𝑖𝑓𝑓𝑢𝑠𝑖𝑜𝑛𝜕𝑆𝜕𝑡

+�⃗� ∙ �⃗�𝑆=𝛼 �⃗� ∙(𝜌 𝐷𝑠 �⃗� 𝑆)

𝑠𝑡𝑒𝑎𝑑𝑦 𝑠𝑡𝑎𝑡𝑒 ,𝑢−𝑑𝑖𝑟𝑒𝑐𝑡𝑖𝑜𝑛𝑜𝑛𝑙𝑦𝑢 𝜕 𝑆

𝜕 𝑥=𝐷𝑠

𝜕2𝑆𝜕 𝑥2

∫𝑢𝜕𝑆𝜕 𝑥

𝑑𝑥=𝐷𝑠𝜕

𝜕 𝑥∫𝜕𝑆𝜕𝑥

𝑑𝑥

𝑢 (𝑆−𝑆0 )=𝐷𝑠𝜕𝑆𝜕 𝑥

Connecting the two: Water Mass Formation in the Atlantic Ocean

𝜕𝑇𝜕𝑡

+�⃗� ⋅𝛻𝑇=𝛼𝛻⋅(𝜌 𝐾 𝑇 𝛻𝑇 +𝜌 𝐾 𝑇 𝛻 𝑇 )

𝑧−𝑑𝑖𝑟𝑒𝑐𝑡𝑖𝑜𝑛𝑜𝑛𝑙𝑦 :𝑤 𝜕𝑇𝜕 𝑧

=𝐾𝑇𝜕2𝑇𝜕 𝑧 2

→𝑤 (𝑇 −𝑇 0 )=𝐾 𝑇𝜕𝑇𝜕𝑧

advection = diffusion

Labrador Sea Water formation temporal variability

Doesn’t seem to be ENSO related: 72-73, 82-83, 87-88, 97-98, 09-10.

Atlantic Meridional Overturning Circulation• “The AMOC is defined as the total (basin-wide)

circulation in the latitude depth plane, as typically quantified by a meridional transport stream function.”

• THC is “currents driven by fluxes of heat and fresh water across the sea surface and subsequent interior mixing of heat and salt.” Rahmstorf (2002).

Ocean basins, sills, and fracture zones

Deep Western Boundary Current

Inverted Echo Sounder

World Ocean Circulation Experimentusing human made chemicals as tracers

Meddies

RAFOS (range and fixing of sound;SOFAR spelled backwards)

Oceanic Microstructure

Fine Structure Profiler

Double Diffusion and Salt Fingeringsimplified equation of state

(𝜌−𝜌 0 )≈ 𝐴 (𝑇 −𝑇 0 )+𝐵 (𝑆−𝑆0 )+𝐶𝑝

=0.2

Langmuir Circulation

Turbulence, convection, Stokes drift

Gliders gather T&S data

Blue Hen Glider

Glider path during Deepwater Horizon event

OCN 5401

Questions?

Chapter 8