Asia and the Tropics Flashcards
the role of Himalayan uplift
- collision between the Indian and Eurasian plates
- caused mountains
when was the Himalayan uplift?
50 mil y/a
what is the asian monsoon?
- seasonal reversal of wind direction
- dramatic seasonal changes in ppt patterns
- summer monsoon provides 90% of the ppt in the region
what drives the monsoon rain?
- strong pressure gradients
- heating in summer over asian landscape draws moisture-laden air from SW pacific
- system switches as pressure gradient is reversed
- cooling asian landmass (H) relatively warm SW pacific (L) creates strong winds across asian deserts
what are loess deposits?
- fine grained, 10-50um, wind-blown sediment associated with strength of asian monsoon
- tends to form unstratified deposits which are unstable when wet
where are the biggest loess deposits found?
loess plateau
middle reaches of yellow river N China
how much area do the semi-arid parts of China cover?
450,000km2
is there erosion at loess deposits?
no
when is loess deposited in China?
during extended cold periods
what are the extended cold periods in China an indicator of?
glacial-interglacial cycle
when are winter monsoon winds strong?
during glacials
what happens in the Inter-Tropical Convergence Zone?
- solar heating at equator, intense sea surface evaporation
- air rises, condenses into rain
- air replaced from N/S
- earth’s rotation causes trade winds
what is the ITCZ?
area of low pressure where N and S hemisphere trade winds meet
what is it called when trade winds meet?
doldrums = violent storms
what is El Nino Southern Oscillation?
- periodic variation in tropical Pacific wind and ocean currents
- El Nino = warming phase high in W tropical Pacific
