12: Monsoon

Question 1

why is monsoon important (4)

Answer 1

water source
agriculture
disaster
glaciers

Question 2

what is a monsoon and where is it prominent

Answer 2

• seasonal reversal of wind regime, characterized by the strong interactions between atmospheric flows and topography
• very proiminent in Asia (especially in South and SE)

Question 3

3 Theories of monsoon

Answer 3

1. Thermal theory
2. dynamic theory
3. jet stream theory

Question 4

thermal theory (5)

Answer 4

• differntial heating of land and sea
• pressure gradient
• large scale sea/land breeze
• orographic lifting and adiabatic cooling
• strong summer precipitation and low winter precipitation
• image 27

Question 5

dynamic theory (3)

Answer 5

• based on position of pressure belts and wind zones
• sun lies overhead between the region etending between the tropics of cancer (summer) and capricorn (winter)
• this shifts the position of the inter tropical convergence zone (ITCZ)
• in december and january (winter): wind comes from north to south into ITCZ
• in june and july (summer) winds come from south to north into ITCZ
• image 28

Question 6

tsunami wave amplitude

Answer 6

• depend on the energy released –> stronger the earthquake the larger the waves will be
• boat far in ocean might not notice it passing but a boat in the harbor will

Question 6

what is a tsunami and where is the term from and how is it created and difference from storm surge

Answer 6

• waves on the ocean surface that can reach great heights when they reach the shore
• japanese term meaning harbour wave
• generated by a major disturbance below the ocean surface like earthquake, underwater volcanoes, or landslides
• different from a storm surge, which is generated by an atmospheric disturbance like hurricane

Question 6

jet stream theory (4)

Answer 6

• upper tropospheric fast flowing air currents
• observed around the region of strong thermal gradient
• due to earth’s coriolis force
• flows from west to east

Question 7

tsunami wave speed

Answer 7

• can be over 800km/h
• tsunami can tarvel across the pacific ocean in less than 1 day
• wave seed slows as it approaches land

Question 8

tsunami wavelengths

Answer 8

vary from 10km to 500km

Question 9

what is a shallow water wave

Answer 9

• when the wavelength of a water wave is large compared with the depth of water
• speed of the wave is given by c= sqrt(gH)
• c = wave speed, g = gravity, H = depth
• so wave slows as it approaches harbor because H gets smaller

Question 10

energy of wave and height

Answer 10

as wave propagates its energy is conserved. As a wave slows down its heigh increases

Question 11

relationship between wave height and depth in deep ocean and wave height and depth in shallow water

Answer 11

• image 29
• so a wave of 1m height in the deep ocean (hd) of 4000m would have a heigh tof 4.5m in shallow water (hs) of depth 10m

Question 12

wind and current speed that exert the same drag force

Answer 12

winds of 50m/s (major hurricane) and currents of 1.55m/s exer the same draf force

Question 13

what is a maelstrom

Answer 13

• powerful cortex in water like ocean, sea, river
• tidally driven
• localized because of bathymetry (depth and shape of the bottom)

Question 14

what are rogue waves

Answer 14

• unexpected large waves
• arise from a superposition (clashing) of multiple waves that are generated by weather disturbances

Question 15

what is a rip current

Answer 15

• strong offshore, surface current
• surface confined (wont suck you down)
• can extend well offshore so can carry you far
• surface signature is a gap in the breakers
• to get out of one you swim parallel to the beach
• waves bring water to the shore making water level slightly higher, which piles up and flows back to the ocean along the path of least resistence

Question 16

what is an undertow

Answer 16

• arises from mass of water being slowly transported to shore by wave action
• more wave action the more mass must be transported back so stronger undertow
• strong near bottom