What key statistic was obtained during the collection of tide gauge data between 1915 and 1921?

The collection of tide gauge data between 1915 and 1921 was critical in establishing a mean sea level estimate for that six-year period. Tide gauges measure the height of ocean water relative to a fixed reference point on land, and analyzing the collected data allows for determining an average sea level. This statistic is vital as it serves as a benchmark for understanding changes in sea level over time, which is essential for various applications, including coastal management, navigation, and climate change studies.

The mean sea level estimate is derived from the continuous monitoring of tide data over time, making it a foundational aspect of hydrographic surveying and oceanography. This value encapsulates the average condition of the tidal environment during that timeframe, providing a clear reference against which other measurements can be compared.

Seasonal variations, average tidal heights, and extreme tidal events, while important in their own right, provide different types of information that do not equate to the single, overarching metric of the mean sea level for that specific period. Each alternative answer focuses on aspects of tidal behavior rather than the compounding value of daily, monthly, and annual fluctuations into a meaningful average height, which is why the mean sea level estimate is the key statistic obtained during this timeframe.