OCN 5401 Chapter 2 Stratification Instructor: Dr. George A. Maul / X 7453

Water is a Unique Molecule Specific Heat (C p ) calories/ gram/ºC joules/ kg/kelvin Water Air Granite Ice Floats!!!

Amount of heat added to or released from one gram of water during a change of state. How much heat is 2260 Joules? Of what significance is this addition or loss of heat during evaporation and precipitation? Deposition

How much heat is 2260 Joules? Heat (H) = mass (m) ∙ specific heat (C p ) ∙ Temperature change (∆T) H = m ∙ C p ∙ ∆T Assume m = 1 kg = 1 liter H 2 O ∆T = ?

Inventory of water at Earth’s surface (from Berner and Berner, 1987)

Seasalts What is salinity? Grams of salt in one kilogram saltwater Bonaire, N.A.

 28m  56m If we evaporate the ocean, how thick a layer of salt would be left behind?  84m Consider a column 5000 m by 1 m 2 square. For S=35‰, salt content is ~35 kg·m -3, density of salt is ~2.1 g·cm -3.

Could the ocean hold more salt? Great Salt Lake, Utah. Salinity range 50 to 270‰

A two-layered fluid

A16 T-S Diagram Iceland-0º 0º - 30ºS 30ºS – South Georgia Island

Depth zones in the ocean Why do these profiles appear as they do?

The previous figure is an average distribution of temperature, salinity and density. However, the surface values are variable with both latitude and season. Here we see the average annual temperature by latitude. Why do they differ?

Oceanic Internal Waves Brunt-Väisälä Frequency pycnocline follower

What about the Cryosphere?

Why do icebergs float? Who was Archimedes? Sea Ice

How high does an iceberg float? We’ll need the hydrostatic equation again p = ρ∙g∙z p up = p down 287 B.C. to 212 B.C. Buoyancy Force F b = g V dρ

What maritime disaster precipitated the formation of the International Ice Patrol?

Blowing up Icebergs?!

A. Southern hemisphere B. Northern hemisphere. Seasonal extent of sea ice

How much frozen water is in sea ice? Sea ice is 0.1% of the total volume of ice on Earth How much of Earth is covered with sea ice? 2/3 of Earth’s permanent ice cover is sea ice. This is approximately 5-6% of the surface area of Earth. Of what significance is sea ice in the Earth System? What happens if it all melts? What happens if more forms?

Please note the size of the sheets of ice breaking off! Approximately 1000 km 3 of glacial ice enters the sea each year as icebergs. (Can you put this number in perspective?) How wide is Florida?

How much heat to melt sea ice? Sea ice is 0.1% of Cryosphere or x 10 6 km 3 or 43 x g of ice. For ice at 0 0 C to water at 0 0 C 330J/g or 79 cal/g ice is required. Total heat required to melt sea ice is 1.45 x J or for the whole Cryosphere is 1.45 x J. For perspective, world energy consumption is approximately 4 x J/year One PB&J sandwich is about 1 million Joules!!

OCN 5401 Questions? Chapter 2