Topic 3 Patterns of Water Movement

3.1 Interactions between atmosphere and ocean

Nature of science:

Understandings:

Structure of the atmosphere including the tricellular model of atmospheric circulation
The ocean influences the atmosphere because of the thermal properties of water
Both atmosphere and ocean are influenced by Earth's rotation (Coriolis effect)
Differential heating of land and ocean waters, which heats air which sets up convection systems in the atmosphere that generate wind causing water to move as waves and currents
Speed and direction of wind determine currents
Duration, speed and fetch of wind over water determines the development of waves
Ocean currents can influence climates of continents

Applications and skills:

Skill: measuring differences in heating of air over water and air over land to construct a model of influences of sea and coastal land and the diurnal occurrence of sea and land breezes
Skill: map prevailing winds and the resulting surface current patterns

Nature of science:

Understandings:

Chemical and physical properties of water allow co-existence as vapour, liquid and solid within the temperature and pressure ranges found on Earth.
Sublimation, evaporation, transpiration, condensation and deposition have energy consequences that influence temperature and moisture of atmosphere
Movement of water from one reservoir to another also moves energy/heat.
Water is the principle greenhouse gas in the atmosphere
Stability of the water cycle, or lack of stability, dictates the changes in climate
The high heat capacity of water affects the ocean system

Applications and skills:

Skill: Constructing a diagram of the water cycle indicating storages/reservoirs and flows.
Skill: Calculating energy exchanges for hydrologic processes

Nature of science:

Understandings:

Anatomy of a wave including direction of water movement within a wave
Waves are measured as to height, wavelength, steepness, speed, period and frequency
Energy/movement passes through the water causing waves
Wave train indicates the direction of movement of energy
Causes of waves and factors affect wave propagation including depth of water, wind speed, duration and fetch
Swells are waves that are no longer under the influence of the wind
Types of waves: deep water waves, shallow water waves, episodic (rogue) waves, internal waves, standing waves (seiches), swells, breakers

Applications and skills:

Skill: use wave tank measuring changes in waves in relationship to water depth
Skill: drawing profile of water movement in waves as they enter shallow water
Skill: calculating steepness and celerity of waves from given dimensions
Skill: showing changes in direction of a wave train as it enters a bay or strikes a headland
Application: effects of wave energy on coastal erosion

Nature of science:

Local conditions affect the generalized expectations for applied theories.
Natural phenomena have complex explanations in order to have predictive value. (i.e. equilibrium tidal theory predicts that the highest tides each month will occur at the new and full moons, but usually they do not. How can this be reconciled?)

Understandings:

Tide patterns are based upon water level and timing
Patterns are described as diurnal, semi-diurnal, mixed, spring and neap
Equilibrium tidal theory and dynamic tidal analysis contribute to understanding tides
Landmasses, phase of the moon, shape of ocean basins, latitude, declination of the moon and weather affect tide patterns and the currents resulting from them
Tide tables predict times of high and low tides
Tides are used to produce an alternative energy source

Applications and skills:

Skill: using a current table to estimate times and velocities of maximum ebb and flood tides and estimating slack water time
Skill: using a tide prediction table to generate a graph of one month of the expected tide pattern at a given tide station (practical 2)
Skill: using the internet to examine and explain a real water level in comparison to the predicted tide water changes at a named tide station.
Discussion of the importance of tide and tidal current prediction

Nature of science:

Benjamin Franklin crossed the Atlantic Ocean several times on his voyages from the American colonies to England. He took many readings of the ocean water and charted them against existing maps. The detail and quantity of data collected lead to recognition of a major current between the two continents. It is an example of collection of data that served to confirm earlier information separately mapped by Resen based upon the data of Frobisher.

Understandings:

There is a dynamic relationship between prevailing winds, land masses, Earth's rotation and velocity of surface currents in ocean
Earth's rotation causes the Coriolis effects.
Currents transport heat, water, debris.
Currents are measured as to their speed, direction, temperature and size (volume of water)

Applications and skills:

Skill: On a map draw major gyres for Pacific and Atlantic Oceans.
Skill: Mapping current patterns and calculating speed by use of shipping debris records.
Skill: Determining velocity of a wind driven current from dimensions of the wind (speed and direction)
Skill: Designing or explaining the design of a device to measure a current in a body of water.

Nature of science:

Discovery of the global ocean conveyor belt demonstrates the value of collaboration and decades of persistent research.

Understandings:

Salinity and temperature affect density of seawater.
Density varies; more dense water sinks whereas less dense water rises resulting in thermohaline circulation.
Evaporation, sea ice formation, and wind shear increase salinity and thereby, density of surface water
Evaporation by winds, causes water in the north Atlantic to become salty and sink, setting the Ocean Conveyor into motion.
Upwelling (caused by winds) causes deep dense water to rise to the surface.
The ocean conveyor moves ocean water in a persistent pattern.
Patterns of upwelling and downwelling occur seasonally and have implications for ecosystems.
The El Niño and La Niña phenomena have impacts on ecosystems, climate and economies
While the causes are not fully recognized, El Niño and La Niña sequences have been described.

Applications and skills:

Skill: Using data from the TAO/TRITON Array in the Pacific to explore a question.

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