Tides - Tidal signatures Flashcards
1
Q
methods to measure tides
A
- fixed boards
- stilling well
- acoustic echo sounder
2
Q
characteristics of tides
A
- types of tides
- daily lag
- diurnal inequality
- spring-neap cycle
3
Q
Type of tides
A
- semi-diurnal: F=0.7
- mixed. predom. semi-diurnal: F = 1.41
- mixed. predom. diurnal: F = 2.12
- diurnal: F=19.96
4
Q
Two dominant tide periods - diurnal
A
one tide crest and trough every 24 hours
5
Q
Two dominant tide periods - semi-diurnal
A
one tide crest and trough every 12 hours
6
Q
Daily lag
A
due to the earth’s rotation on its axis the moon advances about 1/29th of its orbit
7
Q
Diurnal inequality
A
lunar declination caused by the sun and moon
variation in height that is observed between adjacent high and low waters
8
Q
Spring-neap cycle
A
phase changes of the moon
variation due to combination of moon and suns gravitational fields
9
Q
Deficiencies of equilibrium tidal theory
A
limited tidal speed
water mass has inertia and experiences bottom friction
the ocean depth is irregular, not constant
