February 13th lecture Flashcards
What is a Doldrum?
A region of light wind that separates trade winds in both the northern and southern hemispheres.
( basically associated with the ITCZ)
What effect does continental shift have on the doldrums?
The position of the
continents shifts the doldrums into the northern hemisphere (instead of directly on the Equator)
What direction do northern Hemi-sphere trade winds point?
south west towards the atmospheric intertropical convergence
What direction do Ekamn Transports point in the Northern hemi-sphere
North west - making right angle with trade winds
What direction do southern Hemi-sphere trade winds point?
North west -atmospheric intertropical convergence
What direction do Ekamn Transports point in the southern hemi-sphere
above the equator they point to the North East towards the atmospheric intertropical convergence
below the equator they point South west away from the equator, making a right angle to the trade winds
What is the cause of the high sea surface near doldrums?
there is a region of high sea surface near the the doldrums, produced by the northward Ekman transport in the region just north of the Equator
What causes the westward South Equatorial Current (SEC) (northern hemi-sphere0
Flow from 5°N is directed south
by the pressure gradient and then turned to the right by the Coriolis Effect, helps strengthen SEC
What causes the westward South Equatorial Current (SEC) (southern hemi-sphere)
Flow from 5°N is directed south
by the pressure gradient and then turned to the left by the Coriolis Effect, helps strengthen SEC
Farther north, what currents are generated?
The North Equatorial Current (NEC)
and
the Equatorial Counter Current (ECC) are generated
What do the strong currents to the west lead to?
It leads to water piling up along the western boundary
what is created to balance the westward pilling of water?
The Equatorial undercurrent (EUC) is generated
What is the Equatorial undercurrent (EUC)
a strong and fast current that flows directly along the Equator
At what depth is the EUC found?
at 50-300m depth
What direction does the EUC travel? Why?
Flows purely east-west as no
Coriolis deflection at the Equator, and should it deviate north or south the Coriolis affect pushes it back to the equator.
How long is the EUC
thousands of Km’s flowing from west - east across the tropical pacific.
What is the Indian ocean comparable to?
A southern hemi-sphere basin
Why does circulation reverse seasonally?
because of the Monsoon?
What is a Monsoon?
Monsoon is a word that means seasonal
What drives the winds in the Indian Monsoon?
Heating and cooling drives winds that change between winter an summer.
What happens during the summer of the Indian monsoon?
- Strong heating warms Asian land mass faster than ocean
- Creates low atmospheric pressure, rising motion precipitation, and onshore winds
What happens during the winter of the Indian Monsoon?
- Air over land rapidly cools, creating higher pressure
- This drives offshore flow from land to ocean, and dry conditions over land
What effect do changing seasonal winds have on the ocean?
they cause major currents to switch directions, they also change directions of Ekman transport and resulting geostrophic currents.
The Indian ocean is the only place in thw world that this happens
