1 / 16

Computing Tides

tuyen
Download Presentation

Computing Tides

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    2. Newcomer’s Tide Questions Tides are caused by the gravitational attraction of the sun and moon but…. Why are there sometimes two tides a day? Why are tides really high and low twice a month? Why are the really low tides in the middle of the night in the winter and midday in summer? Is there better information available than the Times Colonist tide tables? Can computer resources answer the “Whys”

    3. Computer Resources Google “Tide Tables” to find Canadian Hydrographic Service – Tide tables and graphs – Information NOAA – Excellent background information – US tide tables and graphs Tide Simulators: Harmonic Analysis – Freeware “WXTide32”

    4. Canadian Hydrographic Survey Click on http://waterlevels.gc.ca and follow the links, maps etc for your location For Sidney click on http://waterlevels.gc.ca/cgi-bin/tide-shc.cgi?queryType=showFrameset&zone=9&language=english®ion=1&stnnum=7260 For presentation I prefer Graphic, a plot of the tide levels for a week

    5. Graphic from waterlevels.gc.ca

    6. US Tidal Information: NOAA National Oceanic and Atmospheric Administration NOAA Tides Online http://www.tidesonline.nos.noaa.gov “Our Restless Tides” Online Tides Primer http://www.co-ops.nos.noaa.gov/restles1.html “About Water Levels, Tides and Currents” http://www.co-ops.nos.noaa.gov/about2.html Harmonic Analysis http://www.co-ops.nos.noaa.gov/harmonic.html

    7. NOAA Tide Graphic

    8. Offline Resources NOAA Documentation (Fortran) derivatives XTide: UNIX program by Dave Flater http://www.flaterco.com/xtide WXTide32: a free Windows tide and current prediction program by Mike Hopper - http://wxtide32.com

    9. Computing Tides on your PC Windows Tide and Current prediction program http://wxtide32.com/ Install the free shareware on your PC. Set up your preferences like Location Program data base includes more locations than Canadian Hydrographic website, including Deep Cove, Swartz Bay etc. It also includes locations for currents, including Porlier Pass, Active Pass, Race Passage etc.

    10. Typical WXTides32 Screen

    11. Harmonic Analysis Sum of waves of different amplitudes and periods – Sun: 12 hr, 24 hrs, 1 year etc – Moon: 11.5 hr, 23 hr, monthly etc – Shallow vs deep – funnel effects – Time delays – LC resonance: velocity, volume, frequency

    12. Sun and Moon Effects

    13. Sun and Moon Effects

    14. Latitude & Season Effects

    15. Latitude & Season Effects

    16. Tidal Currents Online Click on http://www.bigwavedave.ca/latest.htm Click on Tides Button Click on map: Currents Blue, Heights Red Daily Tidal Current Predictions for Race Rocks, Juan de Fucha, Active Passe

    17. Conclusions Computer resources abound for answering virtually every question Tide predictions are one good example Start with Google or a reference link Paste your notes into a file as you go Put together a presentation or article to document and share your results

More Related