The average height of the surface of the sea...

Question 1 of 2707066636ee928f7522a1c5191cf

The average height of the surface of the sea for all stages of the tide over a 19 year period is known by which term?

Back

Question 1 of 27070

Q

The average height of the surface of the sea for all stages of the tide over a 19 year period is known by which term?

🔍 Key Concepts

• Tidal datums used on nautical charts • The special 19-year tidal cycle used to average water levels • Differences between mean, high, and low water references

💭 Think About

• Ask yourself: Which term describes an average of all observed sea surface heights over the full tidal cycle, not just highs or lows? • Which choice is commonly used as a vertical reference (zero) for elevations on charts and coastal construction? • Which options clearly refer only to high water or low water conditions rather than the whole range?

✅ Before You Answer

• Verify which term includes all stages of the tide over the standard 19-year period • Check if any option refers only to the high or low part of the tide—these would not match the question wording • Confirm which term is widely used as the reference level for long‑term sea level measurements