Tides and SLR

Question 1

most tides controlled by

Answer 1

lunar cycle

Question 2

Perigree

Answer 2

low orbit (moon close to earth)

Question 3

Apogee

Answer 3

high orbit (moon further from earth)

Question 4

Earth influenced by gravitational pull from…

Answer 4

moon and sun

Question 5

spring tide

Answer 5

when the sun, moon and earth are in alignment = biggest tide (occur twice per month) semidinurnal

Question 6

Semidiurnal tides

Answer 6

two high tides and two low tides per 24 hours. (1 high and low every 12 hours) - common nz

Question 7

mixed semidiurnal

Answer 7

dissconnected symmetry but still one high and low every 12 hours. (24 hours - diff highs and lows) inequality

Question 8

diurnal

Answer 8

one high and low over lunar day (24 hours)

Question 9

Can we alter tides (e.g. CC)?

Answer 9

Cannot control tides, cycle continues forever, no matter what we do on earth surface

Question 10

Micro-tidal

Answer 10

0-2m

Question 11

MESO tidal

Answer 11

`2-4m

Question 12

macro-tidal

Answer 12

4-6m

Question 13

mega-tidal

Answer 13

6+ m

Question 14

coasts can be a mix of dominated processes

Answer 14

tide, co or wave dominated

Question 15

why are tides important in coastal systems?

Answer 15

Determine:
- where on the shore wave energy works
- vert and horiz shore distance over which wave energy is spread
- zones where species live
- tidal currents are an ocean/coastal energy source

Question 16

Are tides predictable?

Answer 16

yes (predict week in advance)

Question 17

transgressive conditions

Answer 17

onshore migration of coastal landforms and deposits SHORELINE RETREAT

Question 18

regressive conditions/progradation

Answer 18

coastal emergence and or progradation (land extending out to sea) SHORELINE ADVANCE

Question 19

sea level

Answer 19

intersection btw sea edge and land that can shift landward or seaward depending if sea rise or fall (assume no change in land height - wrong! Tectonics)

Question 20

mean sea level

Answer 20

(made up) statistical average of conditions over many years. Varies from place to place

Question 21

Relative sea level (RSL) change

Answer 21

regional por local changes in water level due to changes in sea level or land positioning

Question 22

absolute sea level (Eustatic SL) change

Answer 22

global scale change in ocean water. Independent of land

Question 23

5 causes of sea level change

Answer 23

ecstatic, isostatic, steric sea level change, tectonism, compaction

Question 24

eustatic sea level change

Answer 24

ocean volume changes esp with ice sheets

Question 25

steric sea level change

Answer 25

thermal expansion of oceans (warm water molecules take up more space than cold ones

Question 26

isostatic sea level change

Answer 26

Changes in land level due to rebound of land after melting of ice (buoyancy - as lifts sl drops)

Question 27

tectonics

Answer 27

Changes in relative land level position may be as subsidence in inter-seismic (btw EQ) or uplift during co-seismic events (during EQ)

Question 28

Compaction

Answer 28

relative changes in density of loose sediments (become dense due to compaction - ground subsides relative sL rise!)

Question 29

sea level in the past

Answer 29

had high (warm period), and cold stands (cold period) but little variation mostly

Question 30

sea level across the globe

Answer 30

Different across globe, SLR in one area DOES NOT EQUAL SLR in another

Question 31

biggest driver of SLR

Answer 31

thermal expansion - takes time to heat deep ocean water, heat transferred through energy migration. Can’t see problem so don’t do anything to change it!

Question 32

Inverted Barometer Effect

Answer 32

Describes sea level response to changes in atmospheric pressure (important contributor to storm surge) high pressure - water level drops locally, low pressure - water level rises locally.

Question 33

Storm surge

Answer 33

abnormal rise in sea level above the normal tide levels

Question 34

ground water impacts of SLR

Answer 34

under threat as SLR and extreme weather events become more frequent - hazard as seawater pushes ground water upwards - potential flooding.