water and ocean structure Flashcards
what is heat
Energy produced by the vibration of atoms/molecules
what is temperature
Records only how rapidly the molecules of a substances are vibrating
*water molecules in hot water vibrate more rapidly than in cold water
what two pure water’s significant properties is Celsius (o C) based on
Freezing point – 0 o C
Boiling Point 100 o C
what is heat capacity
A measure of heat required to raise the temperature of 1gram of a substances by 1 o C
what is a calorie
the amount of heat required to raise the temperature of 1 gram of pure water by 1 o C
how does water temp affect its density
- Close to freezing point, water density actually decreases when temperature continues to cool
- Ice is lighter than an equal volume of water
- Ice density increases with colder temperature, but never reaches that of water
how does evaporative cooling work
Water takes energy from somewhere to evaporate and remove heat from surfaces as it does e.g. water sweat takes heat energy from our bodies to evaporate, cooling us down
how does Seawater and pure water have slightly different thermal properties
- Seawater is ~ 96.5% pure water and ~3.5% dissolved solids and gases
- Lowers freezing point
- Also changes calories needed to raise temperature
what is thermal inertia
tendency to resist a change in temperature
- ~18,000 cubic km of ice thaws and refreezes in the Southern Hemisphere every year – moderates Earth’s temperature
what moderates Earth’s temperature
Weather and Currents
where is the most evaporation
peaks in subtropics not tropics – need colder air over warm water for evaporation – air and ocean are both warm in tropics
3 Ocean density stratification zones
Surface zone / mixed layer – 2%
Pycnocline – 18%
Deep zone – 80%
how do conditions change in all 3 zones
- Surface layer conditions are rather constant – good mixing due to surface wind mixing
- Pycnocline changes rapidly (cline = quick change)
- Deep zone – minor changes
what is a Thermocline essentially
difference in temp on surface vs depths
- Polar waters lack a strong thermocline
how does Thermocline depth and intensity vary
with season, local conditions (e.g. storms), currents, as well as other factors
what is refraction
bending of waves
- can Bend the Paths of Light and Sound Through Water
- can create shadow zones - regions where sound waves are blocked or do not travel effectively due to sound refraction
what is Refractive index
degree that light is bent traveling from one medium to another
2 main light zones in the ocean
Photic zone – sunlit portion
Aphotic zone – no light
does light or sound travel further in the the ocean
Sound Travels Much Farther Than Light Through the Ocean – but varies with depth (effected by temp and pressure)
whats the SOFAR layer
naturally occurring, deep-ocean sound channel where sound waves can travel long distances with minimal loss of energy - due to the unique way temperature + pressure affect the speed of sound in water
what can be used to detect Underwater Objects and its 2 types
Sonar Systems
- Active sonar (sound navigation and ranging)
- Passive sonar – listening only
what can be used to monitor the changing climate
sound through ocean - as its influenced by temperature, pressure, and salinity
