EAS Exam 2- Clines and Onwards

Clines are

transition layers within the water column between the top mixed layer and deeper water

Pynocline

layer of water in which there is a change in density with depth

What is driving deep ocean circulation

differences in density (driven by temp and salinity)

Density is controlled by

temperature and salinity

Density increases as depth

increases

Convection (heated from bottom) is only for

troposphere

The ocean and stratosphere both are

not convective; stratified/heat from top

For ENSO cycles, a positive Nino index means

El Nino, (warming temps due to trade winds)

For ENSO cyles, a negative Nino index means

La Nina, (lower temperatures)

Nino Index

Water is densest near the

poles, due to sea ice formation increasing salinity

Thermocline

layer of water in which there is a change of temperature with depth

Ocean temperature _____ as depth increases

decreases

Thermocline characteristics

Varies from Season to Season

Semi-permanent in tropics

Variable in temperature regions

Shallow to non existent in polar region

Global Annual Avg SST (Sea surface temp)

Equator and tropics stay more consistent because water is warmed year round

Halocline

is a layer of water in which salinity increases with depth

Salinity at coastlines is low due to

freshwater runoff

The ocean’s salinity is around 3.5%

for every 1L of water, 35g of salt is dissolved

Salinity is enhanced by

Sea ice formation & evaporation

Salinity is reduced by

Precipitation & runoff

Salinity is equal to

(mass of salt)/(mass of ocean water)

What is the relevancy of Hadley Cells in this lesson

Air sinking at mid-latitudes forms high pressure regions at surface, meaning less rainfall and more evaporation AKA MORE SALT

Surface circulation is

0-100m & 10-100 cms/second

Deep ocean circulation is

few centimeters per second

Surface Current Circulation is driven by

Surface winds

Continental boundaries help with circulation by deflecting waters towards the

poles or equator

Circular current: East Coast

warm gulf stream contributes to warmer waters as compared to pacific coast; gulf stream moves warmer water to poles

Boundaries of gyres are associated with

excess heat transport to poles as well as transport of cold water toward equator

Gyres are formed by

wind patterns, continental bounds, coriolis effect

There are _ main gyres

5

Surface circulation is dominated by the circular movement of gyres; gyres move ___ in northern hemisphere and _____ in southern

gyres move clockwise in N hemisphere and counterclockwise in S hemisphere

The GPGP is the

Great Pacific Garbage Path; Northern Pacific Oceanic Gyre; largest of 5 offshore trash zones (around 1.6mil km)

Bioaccumulation

increase of a substance in the food chain (microplastics are accumulating!)

_____ are the main source of ocean plastic

Rivers

Ekman Spiral

due to combination of friction and coriolis forces, surface waters deflected ~20-45 degrees

Ekman Spiral has a net direction of 90 degrees to surface wind which is

right in the Northern hemi and left in the southern hemi

As depth increases, the ekman transport

decreases

Ekman Transport results in the _____ in the center of gyre

convergence!! and downwelling!!

Downwelling is the

sinking of water due to accumulation of converging water

Upwelling is the

rising of colder water due to divergence; brings up lots of nutrients

Deep Ocean circulation is driven by

differences in heat and salinity

Heat and salinity differences give us

thermohaline circulation

Thermohaline circulation

global conveyor belt, stirs ocean from top to bottom (full cycle 1000 years), feedback in climate change

Global Annual Average SSS is

Sea Surface Salinity

CFC (Chlorofluorocarbon) concentration is used to trace the

time of deep-water circulation

Why is thermohaline circulation important

Climate change and ocean mixing

Boundary current

ocean current that is strongly influenced by coastline

Wester currents bring

warm water to poles from tropics