lec 6 greenhouse gases, atmospheric circulation

atmosphere becomes mostly transparent to long wave radiation around

8-10 km, water vapor can’t be held because it’s cold

weather occurs in

troposphere

hot air warmed by surface

rises, keeps rising until it is same temp as surroundings

moist air is less dense than dry air because

water vapor is less massive than the other fasses

when moist air rises and gets to colder temps

it condenses into clouds

hadley cell

warm moist equatorial air rises and moves towards the poles

low pressure areas

convergence with counterclockwise rotation → rising air → divergence and cloud formation

high pressure areas

convergence → sinking air → divergence with clockwise rotation

westerly winds driven by

temp contrast between the poles and equator

jet streams

narrow ribbons of high winds at boundaries between the cells

as arctic warms more than equator, polar vortex

becomes weaker and likely to move