D32ogoqmya1dw8.cloudfront.net



TIDESMost people’s lives or jobs are not affected by the tides, so in general there is not much interest to understand tidal variations. However, there are situations where understanding tidal variations is very important for businesses as well as for pleasure. This exercise covers several different scenarios where it is important to understand tidal variations. After some introductory matrials, you will be the consultant who analyzes tidal charts to help determine the best days and times in various situations.INTRODUCTIONAs with all subjects, there are some basic vocabulary terms that need to be defined so that the topic can be discussed conveniently. Match the vocabulary term on the left with a definition on the right. You will be referring back to this page throughout the exercise, so be sure to check with you instructor to confirm that you have matched them correctly.ebb currenta minimum tidal height diurnal tidal patterntwo high and two low tides of about the same height each dayhigh tidea table that gives the height of the tide above the MLLWMLLWwater flows out of a bay or river as low tide approachessemidiurnal tidal patterntwo high and two low tides of unequal heights each dayflood currenta maximum tidal height low tidewater flows into a bay or river as high tide approachesmixed tidal patternone high and one low tide each daytide chartMean Lower Low Water, average height of the lowest tide recorded at a station, used comonly as a tidal chart datum (i.e., the “zero” tide level) 1. The chart below shows the predicted tide level during a 2-day period of time for Crescent City, CA on July 24 and 25, 2007. Answer the questions below based on the chart.-4572003175 HYPERLINK "" \t "_top" How many high tides (or peaks) are there each day?If there is more than one, are they the same height above MLLW?How many low tides (or troughs) are there each day?If there is more than one, are they the same height above MLLW?What type of tidal pattern occurs at Crescent City?What is the maximum tidal range during this 2-day time period?2. The chart below shows the predicted and observed tide level during a 2-day period of time for American Samoa on March 21 and 22, 2013. Answer the questions below based on the chart.027940How many high tides (or peaks) are there each day?If there is more than one, are they the same height above MLLW?How many low tides (or troughs) are there each day?If there is more than one, are they the same height above MLLW?What type of tidal pattern occurs at American Samoa?Did this area experience an ebb current or a flood current around 10 AM on March 21st ?3. Below is a tidal chart showing the predicted tidal levels for Magueyes Island, Puerto Rico, for the week of May 21-28, 2013. The lightly shaded vertical columns indicate daylight hours. Answer the question below based on the chart.25400360045How many high tides (or peaks) are there each day?If there is more than one, are they the same height above MLLW?How many low tides (or troughs) are there each day?If there is more than one, are they the same height above MLLW?What type of tidal pattern occurs at Maguerey Island?Name the moon phase that was occurring during the first day of this sequence. What about on the last day?4. Below is a tide chart of Cabrillo Beach, CA, for the entire month of May 2013. The heights are given in feet above sea level. Answer the questions below based on the chart.Dr Shadman has asked you to help her plan a class trip to the Cabrillo Beach tidal pools. She wants the class to be able to visit the pools when the tide is at its lowest so that organisms that live in the lowest tidal zones can be seen.Considering the entire month of May 2013, when would be the best date and time to visit the tidal pools?The class trip will be scheduled such that the students will only be able to visit the pools between noon and 3 pm of any given day. Which date would be best given this restriction?0840740After all of your hard work Dr. Shadman tells you that the class only meets on Fridays, so the visit must occur on a Friday. What date do you suggest now?5. Tidal bore surfing is a very unusual kind of surfing that is only possible in some regions of the world. Surfers actually surf upstream in a river, riding a wave produced by the funneling effect of an incoming (flood) tide from the ocean. In addition to variables such as wind direction and ocean swell, the height of a tidal bore is also a function of the phase of the moon. -228600172720The maximum tidal bore wave height occurs when there is the greatest tidal range. What two moon phases produce the largest tidal range? The “window” of opportunity is typically within 2-3 days before and after these two phases. Tidal bores usually arrive within an hour or two after the predicted low tide. Above is a tidal chart for Cook Inlet, Alaska, for the month of April 2013. You work for a travel company who wants to advertise the best days and times to surf the tidal bore at this location. Remember to consider that people do not typically surf in the dark!Select the BEST day that you would suggest for surfing.Select another day during a different time of the month that would also be likely to see good condition.The company wants to let their surfing instructors go away on a 4-day holiday during the month. When would you suggest this be planned and why?6. Below is a tidal chart prediction for Port Hardy, British Columbia, Canada, for the month of September 2014. The heights above sea level are given in feet. During this month a very special and secret visit from the Queen of England will occur via yacht. Unfortunately there is a treacherous reef offshore that is above sea level if the tide is too low (see diagram). It is your job to decide upon the best date and time during this month for the Queen to arrive safely to Port Hardy. Also, due to the secrecy of the visit, the Queen’s yacht must arrive around midnight.-22860024130MLLW.....REEF4 feet8 feet12 feet16 feet7. INVESTIGATE at home:When Dr. Shadman was mapping for her doctorate thesis in Baja California, Mexico, she and her field assistant would occasionally take a break at the Puertecitos hot springs. These hot springs are located in little rocky pools on the shore of the Gulf of California but they are not always accessible. When the tide is high, they are flooded, and if the tide is very low, they are much too hot. The best time to take a soak is when the tide is ebbing and the heat from the springs warms up the pools that were filled with cold seawater, usually close to the low tide. Given this information, what day would be the best to visit the hot springs THIS WEEK? Well, you need to find a tide chart for Puertecitos. This is how you do it:Go to tide-Click on “Countries J-R”Click on MexicoClick on PuertecitosHere you will find a seven-day chart similar to the one shown above in question #3. Choose a day and time that would provide the best soaking conditions. Note that there will be more than one answer, but you only need to give one.What kind of tidal pattern (diurnal, semidiurnal, or mixed) occurs in Puertecitos?What does the blinking red dot indicate?Now return to the first page and select three other areas in the world. List them here are and indicate which kind of tidal pattern (diurnal, semidiurnal, or mixed) occurs in these areas. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download