Friday, April 18, 2008

Ocean Science 101: How to use the NOAA and Scripps Buoys

I am sure that this will be a review for many of you out there but I thought I would through together a little instructional post on how to use the various types of buoys that we have in the Southern California area.




On the surface buoys are pretty simple to understand. They are basically floating sensor platforms…part weather station and part ocean measuring system. They give us near real-time observations of ocean and weather conditions, usually for a fixed point near a coastline or sometimes in the deep ocean water.

Weather buoys have been around for a long time…they used to be the lifeblood for oceanographers and meteorologists before we had reliable weather satellites. They started out fairly simple measuring wave heights, ocean/air temps, and wind speeds if you were lucky. They were effective though…and for many years they gave the coastal areas, sailors, and surfers advanced warning of incoming storms and increasing seas.

Today buoys are pretty sophisticated, they can give you precise information on incoming swells, even with multiple swells running at the same time. They gather data on wave heights, swell-periods, swell directions, water temps, wind-speeds, wind-directions, and barometric pressure, all of which is broadcast in both radio and digital formats. The digital information is processed by NOAA (and Scripps Institute) computers and is eventually updated on the internet.

With all of the new satellite information and computer wave-models nowadays I think that buoys sometimes get overlooked…or at least people don’t use them as much as they should. Satellite information is great but it is generally pretty small-scale…or so narrow in its view that it misses out on key information. Wave models are good but they are the end result of crunching the mass of data spit out by the various pressure models…and if they get crap data going in (like underestimating the strength of a particular area of fetch) then you get crap data coming out (a wave forecast that misses a swell entirely). With buoys, if they are functioning properly, you get actual measured empirical data. If the buoy is close, or at least geographically relevant, then the buoys are a great way to validate a forecast, or make adjustments as necessary.

For the average surfer the buoys are a great way to paint yourself an accurate picture of what is happening swell-wise and wind-wise in our local waters. Armed with that knowledge you can make good choices on where and when to surf, keeping yourself safe and, almost equally important, helping you score some quality waves.

The two types of buoys

For Southern California there are really just two main types of buoys…and it isn’t that the buoy systems use radically different equipment…it is more about which organization runs/maintains the buoys and how each group presents its information for public consumption.

The two types of buoys are:

1. NOAA Buoys
2. Scripps/Coastal Data Information Program (or CDIP)


Personally I like the Scripps/CDIP buoys better…particularly for Southern California. NOAA’s buoys are good, they have the outer deepwater buoys which are awesome for advance warning of NW swells, but they present their information in a much more convoluted manner that screams government bureaucracy and information systems built by low-bid contractors. What is funny is that the NOAA buoys can actually do almost everything that the Scripps buoys can but you need to repurpose the data in a more useful format.


Finding, understanding, and using the Buoy Information for Southern California

Ok now that we got the background information out of the way I am going to walk you through how I personally use the buoy network, which encompasses NOAA and Scripps/CDIP equipment.

We sort of have to start with how to find and use the buoy info.

First off…probably the most useful and 100% free buoy website is http://www.lajollasurf.org/. This site has been a fixture in my forecasting repertoire pretty much forever…long before I ever became a professional surf forecaster…hell it has been a favorite bookmark since I have had the internet.

So using lajollasurf.org you have a couple of choices in how you start to look at the buoy data…it all depends on preference.

If you are a visual person then I recommend starting here…http://www.lajollasurf.org/buoys.html




If it just looks like your computer threw up all over the page don’t worry…that is normal. If you couldn’t tell it is a bit jumbled at first but you can click on the socal region and eventually it ends up narrowing down the focus to this…

(link to live data http://www.lajollasurf.org/socal.html )



This is more detailed with a larger scale…it helps you get familiar with the locations of the buoys, which can help you determine if the buoy is being shadowed by the coast, nearshore island, or other features. I recommend this view for people that are just getting into checking the buoys…the map view helps you piece the whole picture together much faster.

From this page you can see the current buoy conditions, including the dominant swell direction and swell period. It also overlays it on top of NOAA’s WaveWatchIII swell-model, which is the psychedelic color scheme in the background.

You can mouse over each of the buoys (NOAA buoys with the red arrows and Scripps/CDIP buoys with the blue ones)…



and click one of the buoy stations to get more specific data from that buoy.


NOAA Buoys

You read above that I am not all that stoked on the NOAA buoys…this next section is exactly why.

When you click on a NOAA buoy it lobs you into NOAA’s buoy pages…here check out this live link…http://seaboard.ndbc.noaa.gov/station_page.php?station=46047&unit=E&tz=PST




As you can see it gives you a ton of information…which is ok if you are looking for current info, which is summarized on the first page. But if you need historical data, (which we do because swells do hit in the middle of the night), it disjoints it…so you have to visit different sub-links to paint yourself an accurate picture of what has been going on since you last looked at the buoy.

If you need to get older data then, for most people, I would recommend just clicking the chart-info button for the most important data points…wave-height, swell-period, wind-direction, and mean-wave-direction.



This is the data that you would see…




I know what are saying…

”seriously Adam I have been reading about all the cool shit a buoy can do and you show me this piece of crap”

Trust me I feel your pain…leave it to the government to suck the fun out of something.

Actually this brutally ugly chart is telling me some pretty important info…check this out.




See how the dominant swell period has been holding around 10-12 seconds for the last few days…then it suddenly jumps up to the 22-second swell periods? This is a good indication of some sort of change. Either a new swell is arriving or the other shorter period swell is dropping to a point where the long-period swell becomes dominant. By itself it doesn’t give me the full picture but if I bring in the other buoy info, and my forecast, I can validate that the new SW swell has started to arrive…and that I should start working on my hacking cough so that I can sound convincing when I call in sick to work tomorrow.

It is a lot of work to get info out of the NOAA data…personally I use them for mostly current data…unless the buoy is one of the far-offshore ones that has no Scripps/CDIP counterpart.


Scripps/CDIP Buoys

The data format from these buoys blows doors off the NOAA stuff…about the only drawbacks to these buoys is that they don’t easily present historical data that is older than 24 hours and that they don’t display wind speed/direction.

Here check out a live link…

http://www.lajollasurf.org/oceanside.html




Ok on this buoy page we have all of the summarized and historical data accessiable on the same page and in the same format. It also gives us the full spectrum of swell-directions and swell-periods of the energy in the water at the recorded time.

If you look at the cool looking roulette wheel-thingee at the top left of the graphic. This is showing the current swell-directions, broken out by swell-periods.

The percentage table on the top right shows the distribution of swell energy, by swell period. The graph on the bottom left shows the same thing but in a visual format.

If you mouse-over either the bar-graph or the swell-direction compass you will get that actual “wave-height” of that spectrum of swell-period. So, on the pictured chart for example, you can see that there is 1-foot of swell with 18-second swell-periods coming in from a 200-degree swell-angle.

The grey trending chart shows the historical “combined wave height”…but if you mouse over the chart…say at the -12 hour mark…the rest of the graphic will change to reflect the data that was captured 12 hours earlier. This is a great way to see when a swell started to arrive, how long the initial swell periods where, and how strong it was when it started to show…all of which are good indicators of how strong a swell, and how good of a wave maker, it has the potential to be.

NOTE: There are couple of weak-points to this display…one is that if you have two swells coming in from different directions but with the same swell periods the display will average the swell direction between the two actual directions. So instead of having two swells, one from 260-degrees and the other from 200-degrees, you get one swell coming in from 230-degrees. The other weak point is that the swell is broken up into neat little sections that don’t always reflect the true nature of the swell…particularly if you have more than one swell in the water. Many times you will miss the lower-periods of the swell because they are being “averaged” in with another swell from a different direction. Again this is a good reason to use the buoys in conjunction with a forecast.

Sorry went off on a little tangent there…ok Back to using the buoys

OK here are the steps that I follow.

1. Read the forecast – at bare minimum it gives me a baseline to start working from…even if it is totally wrong (you probably got it from wetsand or something). You will know that you should be looking for something.

2. Check out the buoy map – (or if you are more experienced use the buoy summary list… http://www.lajollasurf.org/buoylist.html)

3. Drill into an applicable buoy – pick a buoy that is close to your location.

I would recommend the Harvest Buoy as a good starting point…it is the most exposed. It sits right off the tip of Point Conception and has no blockage from either the S or the NW…basically you get a clear “pure” view of the swell along the California coast.

From there I would pick a buoy close to your area.

For Santa Barbara and Ventura I would recommend the Goleta Point and Anacapa Pass buoys.

Los Angeles should focus on Santa Monica and San Pedro (which is a little more exposed to W swells).

Orange County has the Dana Point, San Pedro, and Oceanside buoys.

San Diego is lousy with buoys (I guess it helps to have Scripps right in your backyard). I would use Oceanside buoy for S swells and a mix of any of the others, like Torry Pines for WNW swells.

4. Finally just cross check the forecast for confirmation. Is that S swell showing on the right buoys? Is it making it into my beach? Does it look like Trestles or Newport will be the call this morning?

5. If things look correct (or better) then go surf…get off the computer…seriously don’t waste another minute…well unless you are going to click a few more google ads for me…uh then go ahead and spend a few more minutes.


Well that is about it…

I know that was a lot of information to process…it isn’t as complicated as it appears at first…just keep practicing and it will start to click for you. As always if you have questions let me know…I am happy to help you out, hopefully without further brain hemorrhaging.

4 comments:

Yong Jung Shin said...
This comment has been removed by the author.
Adam Wright said...

hahahaaa....thanks man...you rock!

TV de Plasma said...
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Anonymous said...

There are no more weather radio//sattelite map home forecasters anymore. I guess I dont miss the old days from a technological perspective.

RB