Ch.13 World Wave Climate

Ch.14 Forecasting the Waves Science of Forecasting Waves

GNM 1136Mr. Werner

What do you want to know about your destination before you travel there?◦ Surf Consistency◦ Temperatures (land and water)◦ Wind Patterns◦ Animal Life (sharks, jellies, etc…◦ Type of Break (reef, rocks, sand, etc…)◦ Localism◦ Language Barriers◦ Lodging

Questions to Consider

Satellites – radar altimetry Article Link

Wave Measurements from Space

When is the North Atlantic more active? South Pacific? (fig.13.1, 13.2) How do these maps relate to surfable wave

heights?◦ Why are the two ocean basins so different?

Challenge

Hawaii Europe Mediterranean Africa Indian Ocean East Asia Australia New Zealand

North Pacific North America Caribbean Mexico/Central

America South America S. Pacific Islands

Wave Climate Zones

Biggest Waves on Earth? (Fig. 13.3) World’s Biggest Tsunami Rogue Wave Observations off the US West C

oast New York Times Bermuda Triangle – National Geographic

Video

Wave-Current Interaction

Ch.14 Forecasting the Waves

Derived from multiple mathematical models◦ Wind = atmospheric calculations – layers◦ Waves = grid system

Computer calculates predictions every 20 minutes for approximately 10 days = a model “run”

Each calculation builds off of the previous one. Done twice a day. Smooth color lines are used to differentiate

between wave heights. Wave model is highly dependant on Wind model.

About Wave Models

Significant wave height – Hs or H1/3 = average height of 1/3 of all the waves

Significant Period – Ts – average period of about 10-15 successive prominent waves

Peak Period – period on spectrum that contains the most energy. Similar to Ts.

Wave height and period examples

Wave Height & Period

Current data – not predicted (Table 14.1) Look at trends (36 hours) – Multiple uses Delaware Buoy Will the wave height be the same on the

beach?

Buoy Reports

Surface weather analysis chart Lab Activity

Understanding Weather Maps

https://www.fnmoc.navy.mil/wxmap_cgi/cgi-bin/wxmap_single.cgi?area=ww3_atlantic&dtg=2013102106&prod=sgwvht&tau=000

How to Read a Wave Model NOAA – Understanding Wavewatch III Wavewatch III Current Model –WW3 http://stormsurf.com/

Wavewatch III Model

Wave Models can be very tricky because of local bathymetric effects.

Do not rely entirely on one model – combine all models together for the best results.

Look at local winds, tides, period and direction

Be Careful

“The wave models provide an easy to read analysis and forecast of sea state conditions two times per day for 3 days (for the NOAA Suite) and one week (for the FNMOC Suite). The precaution about using wave models for swell prediction is doubly important. It's a model that uses a model to make a prediction. That is, the wave model uses an atmospheric model to determine the future state of the atmosphere, then makes a prediction of how the atmosphere will affect the water under it. So there's lot's of room for error.”

Quote from Stormsurf.com