Tidal Analysis in Florida Keys: Investigating 9 Year Periods & Anomalous Data

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In summary, tidal analysis is conducted in the Florida Keys to understand tides over a 9-year period. This is done by collecting data from gauges and using statistical methods to identify patterns. Investigating 9-year periods allows for a comprehensive understanding of long-term trends and anomalous data can indicate changes caused by natural events or human activities. The findings of tidal analysis can be used to inform decision-making and management strategies for the coastal region.
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anorlunda
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I've been looking at historical tide data for the Florida Keys at http://tidesandcurrents.noaa.gov/waterlevels.html

I understand harmonic constituents. In fact, I found the following data for this location.

Amplitude in Feet, Period in Days, Description
0.2 1 Principal lunar semidiurnal constituent
0.1 1 Principal solar semidiurnal constituent
0.0 1 Larger lunar elliptic semidiurnal constituent
0.2 1 Lunar diurnal constituent
0.1 0 Shallow water overtides of principal lunar constituent
0.2 1 Lunar diurnal constituent
0.0 0 Shallow water overtides of principal lunar constituent
0.0 0 Shallow water terdiurnal
- 0 Shallow water overtides of principal solar constituent
0.0 0 Shallow water quarter diurnal constituent
0.0 1 Larger lunar evectional constituent
- 0 Shallow water overtides of principal solar constituent
0.0 1 Variational constituent
0.0 1 Lunar elliptical semidiurnal second-order constituent
0.0 1 Lunar diurnal
- 1 Smaller lunar evectional constituent
0.0 1 Solar diurnal constituent
0.0 1 Smaller lunar elliptic diurnal constituent
0.0 1 Smaller lunar elliptic diurnal constituent
0.1 28 Lunar monthly constituent
0.1 183 Solar semiannual constituent
0.3 365 Solar annual constituent
0.1 15 Lunisolar synodic fortnightly constituent
0.0 14 Lunisolar fortnightly constituent
0.0 1 Larger lunar evectional diurnal constituent
0.1 1 Larger lunar elliptic diurnal constituent
0.0 1 Larger solar elliptic constituent
- 0 Smaller solar elliptic constituent
0.0 1 Larger elliptic diurnal
0.1 1 Solar diurnal constituent
- 0 Shallow water semidiurnal constituent
- 0 Lunar terdiurnal constituent
0.0 1 Smaller lunar elliptic semidiurnal constituent
0.0 0 Shallow water terdiurnal constituent
0.0 0 Lunisolar semidiurnal constituent
- 0 Shallow water eighth diurnal constituent
0.0 0 Shallow water quarter diurnal constituent


Clearly there is no constituent longer than a year. Also, the sea level trend for this location is 2.78 mm/year; very small compared to the tidal variations.

I plotted the the monthly average low tides for the period 2000-2014 (see the attached picture), I see a strong component with a 9 year period. I'm struggling to understand that. Could it be El Nino effects in Florida?

The same attached file, shows a very anomalous year from about June 2011 to June 2012. I'm struggling to understand that too. My instincts say that a weather event could only disturb the data for a month or two.
 

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I think you need to refer your list of components back to the Doodson numbers. http://en.wikipedia.org/wiki/Arthur_Thomas_Doodson#Doodson_Numbers

The precession of the moon's perigee (period 8.8 years) and the precession of the plane of the moon's orbit (period 18.6 years) should show up somewhere, as "beats" between the periods of the components. But since your OP only shows the periods to the nearest day, there isn't enough accuracy to "reverse engineer" where the 8.8 year cycle is coming from, except by checking the Doodson numbers for each constituent.

Another possibility is that a severe weather event caused a long-term change the depth profile of the sea bed, and therefore changed the amplitude of the tidal components.
 
  • #3



That's really interesting data! It's amazing to see all the different tidal constituents and their amplitudes and periods. I agree that it's strange to see a 9-year period in the monthly average low tides. It could potentially be related to El Nino effects or other weather patterns, but it would be interesting to see if there are any other factors that could contribute to this observed trend. As for the anomalous year from 2011-2012, it could definitely be a weather event or possibly even a data error. It would be worth looking into further to see if there is any explanation for that sudden change in the data. Thanks for sharing this information!
 

1. What is the purpose of conducting tidal analysis in the Florida Keys?

The purpose of conducting tidal analysis in the Florida Keys is to understand the patterns and changes in tides over a period of 9 years. This can help scientists and researchers to better understand the coastal dynamics and potential impacts of climate change on the region.

2. How is tidal analysis conducted in the Florida Keys?

Tidal analysis in the Florida Keys is conducted by collecting and analyzing data from tidal gauges and other monitoring devices. This data is then processed and analyzed using statistical methods and modeling techniques to identify patterns and anomalies.

3. What is the significance of investigating 9 year periods in tidal analysis?

Investigating 9 year periods in tidal analysis allows for a comprehensive understanding of long-term trends and changes in tides. This time frame is also used to align with other environmental data and can provide insights into the effects of larger climate patterns on tides.

4. What do anomalous data in tidal analysis indicate?

Anomalous data in tidal analysis can indicate unusual or unexpected changes in tides. This could be due to natural events such as storms or human activities like coastal development. Identifying and understanding anomalous data can help in predicting and mitigating potential impacts on the coastal environment.

5. How can the findings of tidal analysis in the Florida Keys be used?

The findings of tidal analysis in the Florida Keys can be used by scientists, policymakers, and local communities to inform decision-making and management strategies for the coastal region. This can include planning for future development, mitigating potential impacts of climate change, and preserving the natural resources of the Florida Keys.

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