Sunday, August 5, 2012

RS:X Olympics · Windsurfing Defended · Sea Breeze

RS:X competition concludes with the Medal Races on Tuesday, August 7. NBC brought us a dedicated internet based live stream view for all of Olympic Sailing. Each class had their one day in the spotlight of a complete professional TV sports production. All the bells and whistles including overhead aerial shots, on the water moving camera work, graphic interface to keep us aware of the leaders. The only thing missing was the play by play announcer and a color commentator to explain the race as it unfolded. I guess NBC had a budget after all. True to form, NBC is in masterful control of all its content; but they do share. Have a look (go full screen): RS:X Men Race 3 & 4 ~ RS:X Women Race 7 & 8 ~ RS:X Men & Women Medal Races.  BTW, check out how the above racers use their uphaul line.  

Will the London Games be the last dance for Olympic windsurfing? Maybe. The RS:X Class reported: "The opinion of our legal team is that the decision (to replace windsurfing at the 2016 Olympics) was perverse and unfair and so we issued a claim on August 1st 2012 in the High Court in London for the decision to be judicially reviewed. This is based on a number of assertions including a failure by ISAF to have full regard to the designated criteria for the selection of Olympic classes and to ignore a previous decision that a full evaluation would be carried out on both the RS:X and kiteboard."

The gloves have come off. ISAF responded: "ISAF intends to fully defend the decision of the ISAF Council, which was made in accordance with the ISAF Regulations and the defined decision making processes of ISAF. ISAF expects the normal submission process to be used in order to ask Council to reconsider its decisions and therefore ISAF is extremely disappointed that this course of action has been taken, not least because responding to legal claims will incur substantial and unnecessary legal costs for ISAF and for the Class itself."

Expect some fireworks at the ISAF Annual Meeting in Dun Laoghaire, Dublin, Ireland, November 1 - 11 when the Council will reconsider the decision to eliminate windsurfing. Meanwhile, the Petition to reinstate windsurfing as an Olympic Sport continues to collect more names.

Windsurfing defended · "The Last Word weighed the perennial political question: which is more elitist — windsurfing or dancing horses? It all started with FOX News conservative Charles Krauthammer, who took swipes at Mitt Romney for committing the political sin of sending his very expensive horse to the London Olympics. But one thing he thinks is still more elitist? John Kerry windsurfing. MSNBC's Lawrence O'Donnell dissected the folly in that logic in the latest Rewrite."

But on the other hand: "The Pryde Group, one of the world's biggest players in the marine and adventure sports markets, is proud to announce a partnership with Jaguar Cars and the all-new Jaguar XF Sportbrake. Jaguar will appear on sails, boards, buoys and rider lycras with local market activating the sponsorship in their respective countries.

This partnership will allow the Jaguar NeilPryde Racing Series to enter another level in terms of support, presence and exposure. With successful events already completed utilizing the new RS:One board and featured in the Extreme Sailing Series, the remaining events in Cardiff, Trapani, Nice and Rio promise to provide some exciting and eye-catching spectacles both on and off the water...Mr. Neil Pryde, Pryde Group Managing Director commented: The Jaguar brand represents a leading global brand focused on luxury, lifestyle and performance, their investment with the NeilPryde Racing Series and our successful collaborations to date represent not only a boost to the tour itself but also windsurfing in general."

July this year was an outstanding month for seabreezes here in east central Florida. I sailed almost every day with either a 6.7 Maui Sails Ghost or a 6.1 Legend on a 2012 RRD 116 FSW. Weighing in at 162lbs. and being a well practiced early planer helped me make the average 12 to 18 knot conditions more doable.  I'm also an avid follower of the  local NOAA Forecast Discussion, updated 4 times daily. With their guidance and a neurotic bird dogging of my select stable of wind sensors, I was able to successfully time the onset of planing conditions at my local launch, catching a session almost everyday in July. On a few days, rapidly developing thunderstorms robbed the wind and made it too lightning dangerous to continue sailing. But overall it was a full month of windsurfing. July was hotter than normal pretty much everywhere in the US, so staying at home and air conditioned until right before sailing helped. July also brought the cold water upwelling with water temps in the low 70's (Sebastian Inlet recorded some mid 60's water temps). From the near shore cool Atlantic Ocean water to the middle of the Florida peninsula with low to mid 90's air temps, we had an above average thermal gradient: a significant factor for developing good sea breezes.

The ridge axis was a term used in almost every forecast discussion in July. I asked Dr. Steven Lazarus from the Department of Marine and Environmental Systems at FIT and Scott Spratt from the NOAA Field office in Melbourne, FL a few questions about it:

Where would I find the current position of the ridge axis?

Dr. Lazarus: Check out the Ocean Prediction Center for surface pressure/ridge axis. You can zoom in by clicking on the image - it is really nice...the nice thing about this site is that it lets you see the entire surface ridge over the Atlantic basin and click and zoom.

Spratt: The Surface Wind/Pressure Map from our Real-time mesoscale analyses page is the best place to find the current location of the surface ridge axis. To determine the likely position of the axis in the future up to the next 36 hours, you can look at our local model Forecast. Look here for a higher resolution of the next 18 hours Forecast. The ridge axis (when present) is represented by the zone or elongation of greatest anticyclonic (clockwise) curvature extending from a high pressure center. There are times that a ridge axis will not be present over the peninsula due to an area of disturbed weather (as has been the case over the past several days of early August), or if the ridge is well to the north, an onshore flow will prevail across the entire peninsula, or if the ridge is well to the south, an offshore flow will prevail across the entire peninsula. 

The ridge axis feature is important to the sea breeze. How does its location affect: onset and strength.

Dr. Lazarus: The large scale ridge does affect the strength of the sea breeze which is a mesoscale phenomenon. It's intensity and position will either enhance or reduce the sea breeze. All things being equal - if the ridge axis (E-W) pushes north of our area - the easterly flow in the clockwise circulation will increase (add on to) the sea breeze generated flow. Conversely, if the axis slides south we tend to get westerly surface flow and the sea breeze can be pinned up near the coast or not even penetrate inland whatsoever if the westerly flow is strong. In the former case, the enhanced sea breeze, may be overwhelmed by the large scale easterlies and be hard to identify. This is especially the case in the fall when the surface pressure gradient increases at our latitude. Remember - the winds blow in proportion to the pressure gradient. That is where the intensity of the high comes into play.

Spratt: While there are exceptions, in a general sense, when the axis of the ridge is nearly overhead, local winds are generally light, which allows the sea breeze to form earlier and become stronger. When the ridge is to your south, the large scale wind flow will be offshore (southwest or west winds), which tends to delay development of the sea breeze and slow its migration inland. If the ridge is far enough to our south (usually over the extreme southern peninsula or the keys), the large scale wind flow can be strong enough to totally restrict sea breeze development. When the ridge axis is to your north, the large scale flow will be onshore (east or southeast winds). If the axis is near or just north of the FL/GA line, the onshore flow will often be strong (breezy/windy), and can disrupt sea breeze formation or add only marginally to it (since the onshore flow is so strong already). When the large scale onshore flow is weaker, the sea breeze can still develop and reinforce the large scale onshore flow.

How does the ridge axis effect the development of thunderstorms?

Dr. Lazarus: See my comments above - the former case (enhanced easterlies) - thunderstorms tend to be more west coast located and vice-versa for the westerly flow and northward displacement of the ridge axis (east coast located). The sort of tweener case is the ridge axis over head - ideally that suggests that the winds are primarily sea breeze generated - in this case inland thunderstorms tend to dominate. Keep in mind that this is all idealized...Once thunderstorms develop - things get complicated quickly!

Where do sea breezes originate? Are they broadly located along coastal waters offshore or is there a more localized point of development?

Spratt: The sea breeze boundary tends to initially develop very near the Atlantic beaches (due to temperature differences between the hot landmass and relatively less hot ocean waters). The boundary (onset of wind shift) then usually propagates inland during the day, with the time of development and speed of motion dependent upon the low-level ridge axis position, as described above. On rare occasions (marginally strong SW flow days), the sea breeze boundary can form along the beaches, then be pushed back out over the Atlantic. To further complicate the process locally, small temperature differences between the intracoastal rivers and adjacent landmasses also produce breeze boundaries at times near the Banana and Indian Rivers, etc. Also, as I'm sure you notice as a windsurfer, as the sea breeze circulation first begins to form, the winds become very light (as most of the air motion is vertically rising), then shortly thereafter the onshore flow kicks in and begins to build as the sea breeze boundary starts to propagate inland.

So, by knowing the location of the ridge axis, you can make some general assumptions on when the sea breeze will develop and how strong it will become. The local forecast models also typically do a pretty good job with the strength of the sea breeze (especially the higher resolution model) -- so you can take a look at them and use them to help you make a local wind forecast.

A few knots more of wind can make all the difference for us windsurfers. Is there anyway to predict the strength of a sea breeze?

Dr. Lazarus: In terms of predicting the intensity of a sea breeze circulation - there are some simple analytic models that are a function of the difference between water temperature and land temperature. So from a simple/climatological standpoint - these are good predictors. Hence, sea breeze intensity tends to peak here in early summer (May/June) and then diminishes late summer (Sept/Oct) as the ocean continues to warm while the land is cooling thereby a diminishing temperature differential. Because our summer flow here is a combo of the large scale ridge and mesoscale sea breeze - it is not a simple answer. However the high resolution models (NAM, RUC) are getting pretty close to resolving the sea breeze circulation - so I recommend looking at their output.

What is the relationship between precipitable water, the sea breeze and thunderstorms?

Spratt: Precipitable Water (PW) does not impact the sea breeze, but does have significant impacts on whether thunderstorms develop along the sea breeze boundary as it develops and shifts inland. We have a summary on our web site which describes how the location of the ridge axis determines the prevailing wind flow (this is the large scale component of the wind, NOT taking into account local sea breezes). The prevailing wind flow also dictates the lightning storm coverage pattern for the day. The lightning storm pattern assumes "average" PW values for the given prevailing wind flow. If the PW on an individual day is higher than "average", there likely will be a greater coverage of storms, whereas a lower than "average" PW likely would mean a lower coverage of storms. Check out this web page on Lightning Threat.

Any more help for us wind junkies with anything about the sea breeze?

Dr. Lazarus: You can sign up at the  UCAR Comet Met-Ed module site, log in and take their online sea breeze tutorial. I frequently assign these to my students and they are quite good!  Some other sites that may also help - but not as good as the Comet module: Sea breeze from the U. of Illinois and NOAA Tutorial: Sea breeze.

No comments:

Post a Comment