Ocean-Atmosphere Interactions - Part 1

What is exchanged between the ocean and atmosphere

Gases and water and heat

Why is the ocean important to global climate

Its high heat capacity and latent heat of vaporization help regulate temperature

What are the two most abundant atmospheric gases

Nitrogen at 78 percent and oxygen at 21 percent

How do atmospheric pressure and density change with altitude

Both generally decrease

Why is warm or humid air less dense than cold or dry air

Warming expands air and water vapor has lower molecular mass

What are the three atmospheric layers discussed

Troposphere and stratosphere and mesosphere

What characterizes the troposphere

Lowest atmospheric layer where weather and convection occur

What characterizes the stratosphere

Contains the ozone layer and has limited vertical mixing

What characterizes the mesosphere

Temperature decreases with altitude and many meteors vaporize

What is the purpose of the ozone layer

Absorbs harmful ultraviolet radiation

How do CFCs destroy ozone

UV radiation releases chlorine that repeatedly breaks down ozone

Why is Antarctic ozone depletion especially severe

Polar vortex and ice crystals promote chlorine reactions during spring

What is saturation vapor pressure

Maximum water vapor pressure possible at a given temperature

How does saturation vapor pressure change with temperature

It increases as temperature increases

What is relative humidity

Actual water vapor relative to the saturation amount

What happens when warm moist air rises

It expands and cools and may condense into clouds

What is adiabatic cooling

Cooling caused by expansion without heat exchange

How do evaporation and condensation transfer heat

Evaporation absorbs latent heat and condensation releases it

What drives atmospheric convection

Density differences caused by unequal heating and cooling

What are convergence and divergence

Convergence brings fluid together while divergence spreads it apart

What is the ocean-atmosphere water budget

Balance of evaporation and precipitation and water transport

How does evaporation compare with precipitation over oceans and land

Oceans generally have greater evaporation while land has greater precipitation

What is Earth's heat budget

Balance between incoming solar radiation and outgoing energy

What can happen to incoming solar radiation

It can be absorbed or reflected or scattered

Why do polar regions receive less solar heating

Low sun angle spreads energy over a larger area and increases atmospheric travel

Where does Earth experience net heat gain and loss

Heat gain near the equator and heat loss near the poles

How is tropical heat redistributed toward the poles

Atmospheric circulation and ocean currents

What drives global atmospheric circulation

Unequal solar heating and pressure differences and Earth's rotation

What is the Coriolis effect

Apparent deflection of moving air and water caused by Earth's rotation

How does Coriolis deflect motion in each hemisphere

Right in the Northern Hemisphere and left in the Southern Hemisphere

Where is Coriolis weakest and strongest

Zero at the equator and strongest at the poles

What are the three atmospheric circulation cells in each hemisphere

Hadley and Ferrel and Polar cells

What are the latitude ranges of the three cells

Hadley 0 to 30 degrees and Ferrel 30 to 60 degrees and Polar 60 to 90 degrees

What happens to air in the Hadley cell

Warm air rises at the equator and sinks near 30 degrees

What are the trade winds and their directions

Northeast trades in the Northern Hemisphere and southeast trades in the Southern Hemisphere

What winds dominate the Ferrel cell

Westerlies that blow from west to east

What winds dominate the Polar cell

Polar easterlies that blow from east to west

Where does air generally rise and sink in global circulation

Rises near 0 and 60 degrees and sinks near 30 and 90 degrees

What are the doldrums

Equatorial region with low pressure and weak winds and rising moist air

Why is precipitation high near the equator

Rising moist air cools and condenses

What are the horse latitudes

Subtropical high-pressure zones near 30 degrees with sinking air

Why are many deserts found near 30 degrees latitude

Sinking air suppresses clouds and precipitation

What is the ITCZ

Intertropical Convergence Zone where trade winds meet and moist air rises

Why does the ITCZ shift seasonally

It follows seasonal changes in maximum solar heating

What is the polar jet stream

Fast upper-atmosphere westerly winds near the Ferrel and Polar cell boundary

What causes monsoons

Seasonal shifts in heating and atmospheric circulation and wind direction

Why do summer monsoons bring heavy rainfall

Moist ocean air moves over heated land and rises

What factors control ocean surface temperature

Solar heating and heat exchange and currents and mixing

Why are eastern equatorial ocean regions relatively cool

Upwelling brings colder deeper water to the surface

What two processes primarily control surface ocean salinity

Evaporation increases salinity and precipitation decreases salinity

Where is ocean surface salinity generally highest

Subtropical regions where evaporation exceeds precipitation

Why is equatorial ocean surface salinity relatively low

Heavy rainfall adds freshwater

Why is surface salinity often low at high latitudes

Precipitation and freshwater inputs reduce salinity

Why is Atlantic surface salinity generally higher than Pacific salinity

Differences in evaporation and precipitation and atmospheric moisture transport

What characterizes polar and subpolar ocean climate zones

Cold conditions and ice and relatively low surface salinity

How does sea ice formation affect surrounding seawater

It excludes salt and increases surrounding water density

What characterizes temperate ocean climate zones

Strong westerlies and frequent storms and precipitation

What characterizes subtropical ocean climate zones

High pressure and sinking air and low rainfall

What characterizes equatorial ocean climate zones

Converging trade winds and rising air and heavy rainfall

How are global wind patterns connected to ocean conditions

They influence currents and upwelling and surface temperature and salinit