Tides & Currents

Question 1

What type of tide occurs when the sun and moon are in conjunction or opposition?

Answer 1

Spring Tide

Question 2

What type of tide occurs when the moon is in quadrature?

Answer 2

Neap Tide

Question 3

What type of tide occurs when the moon is in apogee?

Answer 3

Apogean Tide

Question 4

What is apogee?

Answer 4

A celestial body’s furthest point from another body during its orbit around that body.

Question 5

What is perigee?

Answer 5

A celestial body’s closest point to another body during its orbit around that body.

Question 6

A tidal or lunar day is _____ hours / _____minutes?

Answer 6

You could have answered with any of the following: 1. 24/50 2. 24.83

Question 7

The national tidal epoch is ______ years?

Answer 7

You could have answered with any of the following: 1. 19

Question 8

The nodal period is ______ years? What is it?

Answer 8

The time for the moon and sun to repeat their movement in relation to each other You could have answered with any of the following: 1. 18.6 years

Question 9

What is the difference between two consecutive high and low waters caused by the moon’s declination?

Answer 9

Diurnal Inequality

Question 10

How often do the does the cycle of spring and neap tides repeat?

Answer 10

1/2 of the Lunar Month, Synodical Period (29,5 days).

Question 11

The synodical period is _____ days?

Answer 11

You could have answered with any of the following: 1. 29 1/2 2. 29.5

Question 12

How many days long is the orbital period (perigee to perigee) of the moon? What is it called?

Answer 12

Anomalistic Month You could have answered with any of the following: 1. 27.5 2. 27 1/2

Question 13

What tides occur when the moon is at maximum declination?

Answer 13

Tropic Tides

Question 14

What tide occurs when the moon is at 0 degrees declination, or on the celestial equator?

Answer 14

Equatorial Tide

Question 15

What is the period, in days, of the moon’s declination? What is it called?

Answer 15

Tropical Month You could have answered with any of the following: 1. 27 1/3 2. 27.33

Question 16

Define Diurnal Tides

Answer 16

One high water and one daily low water.

Question 17

Define mixed tides

Answer 17

Large inequality between consecutive high water, low water, or both

Question 18

Define semi-diurnal tides

Answer 18

Two high and two low waters daily with little difference between consecutive high and low waters.

Question 19

What are the time variations that can be expected from the listed time in the tidal current tables?

Answer 19

1/2 to 1 hour

Question 20

The fastest water in a channel is normally in the middle of a channel.

Answer 20

The correct answer is: True

Question 21

The fastest water is generally on the outside of a turn in a narrow channel.

Answer 21

The correct answer is: True

Question 22

The fastest water is generally on the inside of a turn.

Answer 22

The correct answer is: False

Question 23

What is the period of no appreciable vertical rise and fall of the tide called?

Answer 23

The stand of the tide. (or Platform Tide)

Question 24

What is a high water or consisting of two maxima of nearly the same height or two low waters with two minima of nearly the same heights with a small depression between?

Answer 24

Double Tide or Agger

Question 25

What is it called when the high water occurs prior to the transit of the moon, due to changes in the relative position of the moon and the sun? When does this occur?

Answer 25

Priming of the Tides - Occurs between the New Moon and 1st Quarter & The Full Moon and 3rd Quarter.

Question 26

What is it called when the high water occurs after the transit of the moon, due to changes in the relative position of the moon and the sun? When does this occur?

Answer 26

Lagging of the Tides - Occurs between the 1st Quarter and The Full Moon & 3rd Quarter and New Moon.

Question 27

What effect does barometric pressure have on the height of the tide?

Answer 27

A low will raise the level and a high will decrease the level. (1 cm per hectopascal change / 13.6 inches per inch Hg change)

Question 28

An increase of in barometric pressure of 1 inch will cause a decrease in water level by approximately _________ inches?

Answer 28

You could have answered with any of the following: 1. 13.6

Question 29

A decrease of in barometric pressure of 1 hectopascal will cause an increase in water level by approximately _________ centimeter(s)?

Answer 29

You could have answered with any of the following: 1cm

Question 30

The seasonal variation in the water level or current, cheifly due to meteorological causes.

Answer 30

Annual Inequality

Question 31

A physical object of marks as a reference for a vertical datum.

Answer 31

Bench Mark

Question 32

Something having a period or cycle of approximately one tidal day.

Answer 32

Diurnal

Question 33

Which has a greater affect on diurnal inequality. 1. the declination of the sun 2. the declination of the moon

Answer 33

The correct answer is: Number 2 the declination of the moon

Question 34

The metonic cycle is _____ years.

Answer 34

Same as the National Tidal Datum Epoch You could have answered with any of the following: 1. 19 2. nineteen

Question 35

Declinational inequality is the same as…

Answer 35

Diurnal Inequality

Question 36

The difference in height between mean higher high water and mean lower low water is…..

Answer 36

Great Diurnal Range, or diurnal range

Question 37

The astronomical occurance creating tide and the affect on the tide happen at the concurently

Answer 37

There may be a lag of several days The correct answer is: False

Question 38

DST for 2012 runs from ______ to _____.

Answer 38

March 11th - November 4th The correct answer is: True