The Science of – Swell Lines

Eschrichtius Robustus

2/25/16- San Diego, California

The surf was huge and perfect, with local buoy readings of 8ft. at 18″, directly from the west. Double overhead+ peaks moved at a velocity rarely experienced. Windless, glassy conditions persisted throughout the morning. Two months of extraordinarily solid surf removed most sand from the beach and left behind piles of rock. With high tide smashing head-high whitewater off the cliff, entry and exit are hectic. After catching several dreamy waves, I went to the top of the cliff to photograph the epic surf from my favorite vantage point. Peaks continuously bent and warped out of the Canyon, thundering in the neon blue-green water. Two bodysurfers began riding waves, sans wetsuits in the 80°, 11am sun. Trading barrel rides, they lasted about 45 minutes.

Winter?

Visions

A pod of 8 dolphins appeared from the south, not out of the ordinary for this area. They rode waves together and kicked out the back. Then I spotted a larger dark spot in the water. I first thought it was the dolphins in a tight bunch. As I watched, it became clear that a gray whale was cruising shockingly close to shore. The dolphins swam circles around the large cetacean as though escorting him into uncharted whale territory.

Gray whales migrate annually from summer feeding grounds east of Alaska to winter nursing grounds along the Baja Peninsula. Spouts and flukes are frequently witnessed along the Southern California coast as the whales move north and south within 2.5 miles of the coastline. The 13,000 mile round-trip migration is believed to be the longest of any mammal.

A common sight in Southern California Nov.-April.

Image: Learner.org

This specimen was apparently a male, getting an early start on the long swim north to Alaska. He continued his cruise along the shoreline, dolphins buzzing around. I was concerned. I’ve spotted plenty of whales and some of them just beyond the breakers. But this whale was now 40 feet from shore and in about 5 feet of water. An unusual and uncomfortable place for a 40 foot, 30 ton marine mammal. I was prepared to call SeaWorld Animal Rescue and help them push the creature back into the sea.

At his closest approach, a wave broke across the whale’s back and he disappeared in the white water. I anxiously watched, thinking he would roll up on the beach anytime. Finally, I caught a glimpse of him as he was headed back out to sea. Probably exhilarated with his first taste of breaking wave energy. He was headed straight towards the pack of surfers sitting at one of the peaks. I watched intently through my camera lens to witness the surfers shock if the whale surfaced in the middle of the lineup. But I never saw the whale again and haven’t heard of a beached whale. So, I’ll just assume that the whale had been feeling the pulses of El Niño wave energy passing by for weeks and wanted a closer look.

-KS

March, 2016March, 2016

Swell Lines Magazine

Astro-Surf

No waves here. Buzz Aldrin in the Sea of Tranquility. Photo taken by Neil Armstrong. Credit: NASA

On July 20, 1969, Neil Armstrong and Buzz Aldrin touched the Eagle down in the Sea of Tranquility on the lunar surface, forever changing the path of humanity. Eventually, humans are sure to extend footprints further into the solar system and out into the galaxy. But as we leave Earth, exploring and starting colonies on other worlds, what are future bodysurfers to do with a lack of liquid water and breaking waves? The Universe is a phenomenally dynamic place. While we may never find a planet as idyllic as Earth, the potential exists for waves elsewhere. Waves are generated by wind blowing over fluid, as our knowledge of alien worlds increases, we find no lack of wind or fluids. Let’s take a look at some possibilities for waves in Space.

Titan_RGB_9-28-12 — Saturn’s Moon Titan. Credit: NASA

The most intriguing candidate in our solar system is Saturn’s moon Titan. Discovered in 1655 and visited by a robot in 2005. Titan is the only other object in our solar system to have stable liquid on its surface. It also has a thick atmosphere, rain, rocky ground, plate tectonics and polar winds. Appears similar to Earth, except for the -290F average surface temperature and seas filled with liquid methane. In 2004, while studying Saturn, the NASA/ESA spacecraft Cassini, deployed a small robotic lander names Huygens to the surface of Titan. On its way through the atmosphere, Huygens took photos of what appear to be watersheds and coastlines along large bodies of liquid. Is that the whitewater of breaking waves along the shore?

Coastlines on Titan. Are those waves? Credit: NASA

In 2014, astronomers announced the discovery of waves on the surface of these Oceans of liquid methane. Planetary scientist, John Barnes stated, “This discovery represents the first sea-surface waves known outside of Earth.” Kraken Mare is the largest sea in the north polar region and is most likely to have fetch for wave generation. On Titan, there is wind and there exists large bodies of liquid. Potential rivermouth and pointbreak setups abound. Someday in the future, astronauts will venture deep into our Solar System and explore Titan. With continued technological progression, spacesuits and materials will be able to withstand the dangers of bodysurfing on Titan.

The north polar region of Titan with Mare full of liquid methane. Credit: NASA — The north polar region of Titan with seas full of liquid methane. Credit: NASA

If the biggest waves are created by the biggest storms, lasting the longest time, with the strongest winds, then imagine the waves created by the Great Red Spot on Jupiter. The ultimate wave model purple, err, red blob! First observed about 200 years ago and likely existing for much longer, this monstrous maelstrom is 19,000 miles wide and would swallow 3 whole Earths. Wind speed in the anticyclone is a consistent 350mph…if there is liquid below that atmosphere, the generated swell is massive! The fastest wind in the Solar System whips around the planet Neptune at 1,500mph. The strongest winds yet discovered in the universe swirl around a black hole at 20 million mph!

350mph wind over 12,000 miles for hundreds of years...big swell. Credit: NASA — 350mph wind over 12,000 miles for hundreds of years…big swell. Credit: NASA

The Hollywood blockbuster movie, Interstellar, hypothesizes a 4,000ft. wave breaking in waist deep water, across an entire planet. Apparently, this is not a wind generated wave but rather the result of extreme tidal forces from a nearby black hole. Although not scientifically plausible, the visualization of the giant wave makes for an interesting mindsurf.

Black hole tidal forces. Credit: Warner Brothers

Artist's conception of an Ocean Planet Credit: NASA — Artist’s conception of an Ocean Planet. Credit: NASA

Recently, astronomers announced theoretical evidence for a 9th planet orbiting our Sun in the farthest reaches of our solar system. Maybe there are exotic waves of liquid oxygen there. Astronomers have found evidence for “Ocean Planets” orbiting other stars, such as Kepler 22-b and Gliese 581d. The surface of these worlds are hypothesized to be covered in liquid water.

There are intriguing possibilities for space-faring waveriders of the future. As our knowledge increases, so do the chances of finding perfect waves elsewhere in the Multiverse.

-KS

Sources:
Space.com-Titan Waves
NASA- Cassini-Huygens Mission to Titan

January, 2016

Swell Lines Magazine

El Niño w/Mark Sponsler

*Mark Sponsler is the creator of StormSurf.com, “a website dedicated to delivering the highest quality marine weather data to those who ride waves.” Sponsler’s weekly forecast videos focus on El Nino indicators year round, regardless of media hype.

El Nino can have profound effects on global weather and ocean conditions. Under normal conditions, trade winds over the equatorial Pacific blow from east to west (Peru towards Asia). This causes warm water to sequester near Asia, and cool water to upwell off Peru. This in turn results in high pressure over the cool water off Peru (producing stable atmospheric conditions) while low pressure and tropical precipitation locks down off Asia.

But about once every 7 years, the trade winds over the equator relax if not reverse direction, with the effect being a flow that travels reverse of the normal direction, or from west to east (Asia towards Peru). When the trades relax or weaken, this situation is know as westerly anomalies. That is, compared to normal for the time of year, the winds have a westerly component to them And when trades fully reverse (they start blowing from the west to the east), this is known as a Westerly Wind Burst (WWB).

A Westerly WInd Burst across the equatorial Pacific Ocean. — A Westerly Wind Burst across the equatorial Pacific Ocean.

WWBs can last for 10-20 days and can blow as hard as 20+ kts. This situation typically occur between New Guinea and the International dateline. When a WWB occurs, it sets the oceans surface in motion moving to the east. The result is warm water off Asia starts migrating east across the tropical Pacific towards Peru. WWBs also typically spawn tropical cyclones, sometimes straddling both sides of the equator simultaneously. Typically the westerly anomaly/WWB cycle starts in Spring or early Summer, with a single WWB, followed by 2-4 more through early Fall, with the warmest waters reaching Ecuador around Christmas.

The warm water doesn’t flow from west to east on the surface. It falls to depth, down about 200 meters, forming a pocket or bubble of anomalously warm water (+7 degs C above normal). That pocket is called a Kelvin Wave, and it travels west to east under the equator for 2.5 months before being forced to the surface first as it encounters the Galapagos Islands, then eventually impacts Ecuador. For each WWB that occurs during the EL Nino cycle, a corresponding Kelvin Wave develops. The more WWBs, the more Kelvin Waves, and the greater the warming in the east.

As a Kelvin Wave erupts in the East Pacific, it warms surface water there, and typically pretty dramatically. This in turn has effects on fisheries and wildlife, especially in the Galapagos, Peru, Central American corridor. Where normally cold upwelled nutrient rich waters are present, now a warmer and far less bountiful food chain is present for fish. Fish stocks leave the area. Local economies that survive off fishing turn non-productive.

Eventually these warm waters, as they erupt near the Galapagos start migrating west by prevailing trades over the East Pacific, moving towards the dateline. Note – the trades don’t completely dissipate in the east. As this cycle progresses, a defined warm water ‘tongue’ develops extending from the Galapagos east and within 5 degrees north and south of the equator reaching west to the the dateline. Depending how warm the surface pool gets and how much area it covers compared to normal determines whether the situation will qualify to be labeled as El Nino. The area of concern is from 5N to 5S and from 120W to 170W, the NINO3.4 area. If temps in this region hold at +0.5 deg C above normal for 3 months, it considered a minimal El Nino. At the top end temps of +1.5 result in a classification of a strong El Nino. As of the Sept monthly reading, this years event was at +1.67 degs C. In comparison, the two strongest El Ninos at their peak in Dec/Jan were at +2.32 (’97/98) and +2.21 (’82/83). Theses were considered Super El Ninos. This years event is already the 6th strongest El Nino ever (as of Sept), and building. And it is tracking mid-way on it’s development path between the ’82/83 and the ’97/98 events, making it possible it too could reach Super El Nino status.

As the surface warm pool builds, it starts interacting with the atmosphere above it, enabling greater evaporation and increasing humidity levels, reducing surface air pressure and increasing the odds for rain in locations of the planet typically bone dry. Likewise as water cools over Asia, surface air pressure builds and drought sets in. Precipitation follows the warmer water across the Pacific, resulting in a complete reversal of the Pacific Basin weather patten.

From a surf perspective, the weather changes associated with El Nino are most pronounced in Fall and Winter months in the Northern Hemisphere. The warm pool feeds more energy into the jetstream, which in turns causes the jet to track further south forming a strong semi-permanent low pressure system just east of the dateline and south of the Aleutians easing into the Gulf of Alaska. The upper level energy feeds development of larger, stronger and more consistent storms tracking across the Norther Pacific, which in turn generates larger, stronger and more consistent surf aimed at breaks in which the jetstream is flowing towards, like Hawaii, California, the Pacific Northwest, Mexico. But because the jetstream is further south, it also offers the specter of much rain and stormy local conditions, making surf conditions less than ideal. During pronounced episodes during strong El Nino years, the jetstream can drive storm energy straight from Siberia clear across the Pacific and directly into the US, often tracking right into normally drier regions of Central and Southern California. This can bring significant rain and snowfall to regions that are typically desert like, having severe economic and ecologic affects. In the Atlantic, the El Nino enhanced jetstream creates upper level shear that suppresses hurricane production.

Sea Surface Temperature Anomalies- Oct. 17, 2015.

So El Nino can be a mixed blessing, depending on where you live.

After El Nino has run it’s course, typically in the early summer following it’s peak, a new pattern emerges: La Nina that has almost the opposite effect. Colder than normal water starts to develop in the eastern equatorial Pacific in the mid summer as the trades start raging from east to west (Peru to Asia). Strong high pressure rebuilds over the eastern equatorial Pacific while low pressure follows the warm waters being blown back towards Asia. By Christmas time the year following El Nino, the North Pacific jetstream is displaced well north, driving up towards the Aleutians into Alaska and northern Canada, and high pressure dominates the NE Pacific pattern. As a result storm and swell production starts to decrease. And the whole cycle is then set to start again.

October, 2015February, 2018

Swell Lines Magazine

The Wind Is Our Friend…Sometimes

“The wind is our friend, anyway, he thought. Then he added, sometimes.” These are the Old Man’s thoughts as he sails home after his epic struggle in Ernest Hemingway’s The Old Man and the Sea. He is describing his life as a wise old fisherman and the plight of waveriders.

Wind is the most vital variable in all of surfing and waveriders are excessively particular about its existence. Thousands of miles from our coast, we want maximum, sustained winds…over a large area, for a long time. Locally, a few days later, we desire minimal wind or maybe light wind blowing from a very distinct, offshore direction. That’s a lot to ask for and it’s the reason we cherish the days with swell and good wind.

We want this thousands of miles away…

…and this at home.

The atmospheric condition which shall not be named. The moment it is mentioned, the conditions begin to deteriorate. “Bro, its soooo glassy out here!”…then the wind picks up, onshore. “Good, the wind hasn’t picked up yet!”…the waves are textured one minute and blown out the next.

It’s a constant struggle. Its the reason we get up at 5am and blow off dinner plans in the evening. We want the best possible wind conditions. Wake up before dawn, groggily drive to your spot in the dark, check the palm fronds. Fist pump…it’s light offshore! But for how long? On average, dawn is the best time of day to surf. Diurnal, prevailing wind patterns guarantee an eventual onshore flow probably 360 days a year. Skateboarding was invented because surfers got frustrated by the afternoon onshores and looked for something to do once the surf blew out.

Each day, good conditions are fleeting. We dread the coming of the onshores. Sometimes the palm fronds and flags are pointed inland even before the sun rises. Sad face. Sometimes the wind is perfectly calm at dawn and stays that way through the morning. Sheet glass. Sometimes the wind is beautiful offshore at dawn before calming into glass through the morning. The ghastly onshores could bring the dreaded texture at 8am or 1pm…the later the better. Sometimes Santa Anas bring strong, grooming offshores all day.

The evening glassoff isn’t guaranteed but it is always anticipated. Sometimes it never comes. Sometimes the atmosphere teases a glassoff before picking up stronger onshore. Sometimes the first sets of a new swell are greeted in the late evening with perfectly calm winds and orange sunset water.

Sometimes we anticipate a swell for days. Good looking size, period and direction. Only to have it onshore at dawn and howling all day, ripping a solid swell to shreds. Other times, without expectations, a windswell will turn on super fun seemingly out of nowhere. Sometimes it’s perfectly glassy all day but the surf is double over ankle. Sometimes it’s pumping but the devil wind won’t quit. But then there are those situations we dream about and mythologize. Perfect, pure groundswell…and a light offshore breeze for days at time.

-KS

August, 2015April, 2017

Swell Lines Magazine

The Science of Coastal Geology- Part 1

We’re all beach people. We’re attracted to the coast for the beauty, serenity and the waves. There are many variations to coastlines around the globe and these changes are the factors that create the great variety of waves. In this multiple-part article, we’ll analyze coastal geology to better understand how differences in a coast’s dynamics dictate how waves break in a given area.

Geology is the Science of the rocks that create landforms and the processes that change those rocks.The coastal environment has many dynamic factors. Plate tectonics, wave energy, weather, rivers, and humans all have an impact on coastal geology. The coast is always changing. Some changes happen daily, like the movement of sand. While others, like the uplifting of land from plate movement, take place over the course of hundreds, thousands and millions of years.

If you observe any stretch of coast, you’ll see that waves break differently on varying parts of the beach. This is because the Ocean bottom varies. Bathymetry is the underwater contours of the seafloor. It is often overlooked as a surf variable. We cannot directly see it and much of it is fixed for our lifetime. But a closer investigation reveals the dynamic and vital story of our coastlines.

Swell approaching a coastline will always refract and bend toward shallow water. Reefs, sandbars, points and submarine canyons cause swell energy to focus and shoal. Because there is a variety of depths along a coast, waves break differently everywhere. Sandbars frequently shift and move as the sand is carried by longshore currents. California reefs are uplifted remnants of the coastal bluffs and marine terraces. Points are created by the uneven shape of a dynamic coast. Submarine canyons form when fresh water runs off the land and erodes a chasm in the continental shelf.

California’s coast primarily consists of sedimentary rocks in identifiable layers. All of these layers are associated with ancestral rock formations and their subsequent weathering, erosion and deposition. According to a sign at San Elijo State Beach, “The coastal bluffs were formed by the accumulation of mineral and organic sediments. In more recent times, the Ocean level has receded, leaving the sedimentary deposits exposed in elevated marine terraces. Once exposed, these terraces were eroded along the seaward margins, leaving the steep coastal bluffs present in the park today.”

Three prominent layers include:

The Del Mar Formation– the bottom and oldest layer of the San Diego coast sedimentary rocks. It is often greenish or gray mudstone, containing many fossils, laid down in muddy lagoons 45-50 million years ago. The Del Mar Formation now forms many of the reef wave setups we have in San Diego.

Torrey Sandstone– a large layer of light colored sandstone that is the main constituent in San Diego’s coastal bluffs. It is roughly the same age as the Del Mar Formation and was laid down as a sandbar and beach deposit.

Monterey Formation– an oil rich layer that is responsible for the tar on beaches and the offshore oil rigs towards Santa Barbara. It is 6-16 million years old and comprises the remains of billions of microorganisms that once swam in a shallow sea. When they died, they sank to the bottom and were covered by sand and silt. With pressure, heat and time, the organisms became hydrocarbons: the source of our much beloved oil. The Monterey Formation is seen throughout the Central Coast and into the Coastal Range Mountains. It makes up many of Central California’s reef breaks.

-KS

Sources:
Mark Bordelon- Irvine Valley College
PBS Coastal Geological Processes

July, 2015February, 2018

Swell Lines Magazine

The Science of Tropical Cyclones

Tropical cyclones are incredibly powerful and dangerous natural phenomena. Every year, coastlines all across the globe are impacted by these tempests. When the storms move toward land, heavy rain, strong wind, storm surge and tornadoes all contribute to their destructive power. Depending on location and strength, tropical cyclones are called tropical depressions, tropical storms, hurricanes, cyclones, typhoons, super typhoons, etc. Wave-riders have a strange relationship with tropical cyclones. We know their power but enjoy their wave energy. Let’s look at the cyclogenesis of these storms.

The sun warms the tropical Ocean and delivers radiant energy to its surface. Wind blows over the water, it evaporates and ascends energetically into the atmosphere. The rising moisture condenses into towering thunderheads. Air rushes upward and the atmospheric pressure in the center drops. This is a thunderstorm.

An organized group of thunderstorms that persists for 24 hours is called a tropical disturbance. When winds exceed 30mph, it becomes a tropical depression. The Earth’s rotation (coriolis effect) drives wind around the warm core of the storm. For the storm to continue to strengthen, it must remain over warm water and encounter minimal wind shear. This is when vertical winds slant the storm, dispersing the heat over a larger area, degrading the storm. Without wind shear, the cyclone remains upright and continues to develop.

When winds reach 39mph, the cyclone becomes a tropical storm and meteorologists give it a name. At 74mph, the storm becomes a hurricane. Hurricanes are characterized by a defined eye and strong low pressure in the center. Around the eye is the eye wall, an area of intense thunderstorms and the storm’s strongest wind. The Saffir- Simpson Scale rates hurricanes based on wind speed. From Category 1, 74-95mph to Category 5, >155mph. Category 3, 4 and 5 storms are deemed major hurricanes with the most dangerous conditions.

A tropical cyclone is a heat engine, fueled by the temperature gradient between the warm Ocean surface and the cooler upper atmosphere. Heat becomes motion as the warm, moist air rushes upward and is replaced by surrounding air.

There are many meteorological resources devoted to studying and predicting the path that a hurricane will take. There are lives and communities at stake. Wave-riders also take a particular interest in hurricane forecasting because the path of storm is a very important aspect of it’s swell generation. Although, tropical cyclones have strong winds, they lack the size and fetch of their extratropical cousins that generate 15-20+ second groundswell. Hurricane force winds might extend 100 miles from the eye and gale force winds another 300 miles beyond that. For ideal swell impact, a tropical cyclone will slowly move toward land, strengthening as it moves but turn away or dissipate before making landfall.

Origin of our North America's tropical cyclones. Image: NOAA — Origin of our North America’s tropical cyclones. Image: NOAA

North America is impacted by two distinct tropical cyclone regions: the North Atlantic and Northeast Pacific. Interestingly, it is hypothesized that cyclones in both originate from the same phenomena. African easterly waves are disturbances in jet stream flowing off Saharan Africa. They can develop into tropical storms in the warm Atlantic or continue across the Caribbean and Central America without development. Reaching the tropical Pacific, the disturbance can develop into a tropical cyclone using the warm water off the coast of Mexico and Central America as fuel.