Tides - Bowditch

Question 1

Tides - main tide generating body

Answer 1

• Moon

Question 2

Tides - Sun’s effect vs. Moon’s

Answer 2

• Sun’s effect is 46% of the Moon’s due to its greater distance from the Earth

Question 3

Tides - semidiurnal tide

Answer 3

• two high and two low waters each tidal day with small differences in the respective highs and lows
• ie. the US Atlantic Coast

Question 4

Tides - diurnal tide

Answer 4

• only single high and single low water each tidal day
• ie. northern shore of Gulf of Mexico

Question 5

Tides - mixed tide

Answer 5

• diurnal and semidiurnal oscillations make a large inequality in high waters, low waters, or both
• usually two high and two low waters a day, but sometimes becomes diurnal
• ie. US Pacific Coast

Question 6

Tides - spring tides

Answer 6

• full or new Moon
• tractive forces are in line
• semidiurnal range is increased

Question 7

Tides - neap tides

Answer 7

• first and third quarter Moon
• tractive forces at right angles
• semidiurnal range is decreased

Question 8

Tides - priming tides

Answer 8

• Moon between new and first quarter
• Moon between full and third quarter
• high tide occurs before Moon transit
• semidiurnal variation

Question 9

Tides - lagging tides

Answer 9

• Moon between first quarter and full
• Moon between third quarter and new
• high tide occurs after Moon transit
• semidiurnal variation

Question 10

Tides - perigean tides

Answer 10

• Moon nearest Earth in its orbit
• semidiurnal range is increased

Question 11

Tides - apogean tides

Answer 11

• Moon is farthest point from Earth in its orbit
• semidiurnal range is decreased

Question 12

Tides - diurnal variations in ranges occur as…

Answer 12

• the Moon and Sun change declination

Question 13

Tides - tropic tides

Answer 13

• Moon is at its max semi-monthly declination
• either North or South
• diurnal tides are at their max

Question 14

Tides - equatorial tides

Answer 14

• when the Moon crosses the Equator
• diurnal effect is a minimum