11 – Ocean Tides. Part A: U.S. Coastal Tidal Ranges & Types

/in /by

Tide Predictions

The questions require assessment of interactive tide charts and tables generated at the NOAA Tide Predictions website (Tide Predictions (Links to an external site.)Links to an external site.). The exercise requires selection of tidal stations from different coastlines specified by the station name from lists organized by States. The questions primarily focus on evaluation of tide predictions for stations from several different coastlines, which are listed in a separate section below. The procedure requires the following sequence:

  1. From among the options for station identity select the State of the chosen station – for example Virginia – from the lists for the appropriate coast – for example East Coast.
  2. From the listing for Virginia find the pertinent station – for example Sewells Point VA (Station 8638610) – and select that link, which will display the tide predictions for the next two days as a chart and a table to the right.
  3. Below the chart select the Begin Date as March 01 2019 and the end date as March 08 2019 from the pull down menus then click the Plot Daily button. The chart will now display seven days of predictions, with the water levels of high and low times shown, and matched by a listing of the time and height of high and low tides in a table below below the plot. Selecting any of the small blue squares at the high and low tide point will display the time that they occur.
  4. Alternatively, expand the Time Range to March 01 2019 to March 31 2019 and again select Plot Daily. The display will change to show the entire month, with the times and heights of tide for the entire month of June below the graph in a scrolled listing. Alternatively, the water levels can be displayed in calendar format by selecting the Plot Calendar option.

One shortcut that facilitates switching between different tidal stations is simply to replace the number of the Tidal Station that appears at the end of the URL. For example, to switch from Hampton Roads (Sewells Point), Virginia (Station 8638610) to Astoria, Washington (Station 9439040) the number 8638610 at the end of the URL can be changed to 9439040.

Examples of the weekly charts, monthly display and month calendar are shown below for HAmpton Roads (Sewells Point), Virginia (Station 8638610), Pensacola, Florida (Station 8729840), and Astoria, Washington (Station 9439040), respectively.

Sewells

Pensacola

Astoria

Question 1

Examine the tide predictions for representative stations from the East Coast during the month of March 2019 focusing on the timing and magnitude of the highest and lowest tidal range (tidal range = difference in water level between successive high and low tides). Based on these tidal data for stations on the East Coast: (i) What are the dates and magnitude of the highest tidal ranges and the lowest tidal ranges for at least two of the stations during March 2019, and (ii) What is the dominant tide type (tide form – diurnal, semidiurnal, semidiurnal mixed) for the East Coast, and why?

A strong answer will supply appropriate data on tides (dates, timing, high & low tides used to calculate highest and lowest tidal ranges) at all least two stations, coupled with a clear statement of the rationale for the tide type that explains the basis for the chosen category.

East Coast Tide Stations

Question 2

Examine the tide predictions for representative stations from the Gulf Coast during the month of March 2019 focusing on the timing and magnitude of the highest and lowest tidal range (tidal range = difference in water level between successive high and low tides). Based on these tidal data for stations on the Gulf Coast: (i) What are the dates and magnitude of the highest tidal ranges and the lowest tidal ranges for at least two of the stations during March 2019, and (ii) What is the dominant tide type (tide form – diurnal, semidiurnal, semidiurnal mixed) for the Gulf Coast, and why?

A strong answer will supply appropriate data on tides (dates, timing, high & low tides used to calculate highest and lowest tidal ranges) at all least two stations, coupled with a clear statement of the rationale for the tide type that explains the basis for the chosen category.

Gulf Coast Tide Stations

Question 3

Examine the tide predictions for representative stations from the West Coast during the month of March 2019 focusing on the timing and magnitude of the highest and lowest tidal range (tidal range = difference in water level between successive high and low tides). Based on these tidal data for stations on the West Coast: (i) What are the dates and magnitude of the highest tidal ranges and the lowest tidal ranges for at least two of the stations during March 2019, and (ii) What is the dominant tide type (tide form – diurnal, semidiurnal, semidiurnal mixed) for the West Coast, and why?

A strong answer will supply appropriate data on tides (dates, timing, high & low tides used to calculate highest and lowest tidal ranges) at all least two stations, coupled with a clear statement of the rationale for the tide type that explains the basis for the chosen category.

West Coast Tide Stations

Question 4

Examine the tide predictions for representative stations from the Pacific Ocean during the month of March 2019 focusing on the timing and magnitude of the highest and lowest tidal range (tidal range = difference in water level between successive high and low tides). Based on these tidal data for stations in the Pacific Ocean: (i) What are the dates and magnitude of the highest tidal ranges and the lowest tidal ranges for at least two of the stations during March 2019, and (ii) What is the dominant tide type (tide form – diurnal, semidiurnal, semidiurnal mixed) for the Pacific Ocean, and why?

A strong answer will supply appropriate data on tides (dates, timing, high & low tides used to calculate highest and lowest tidal ranges) at all least two stations, coupled with a clear statement of the rationale for the tide type that explains the basis for the chosen category.

Pacific Tide Stations