A tornado that is bigger than the Earth: The Great Red Spot

The storms of a gas giant like Jupiter, a planet 1300 times bigger than Earth, are very fierce. Scientists who have studied Jupiter discovered that its high rotational rate – a day is only approximately 10 hours – leads to the formation of moving gas zones and east-west air jets. The air currents in these bands wrap the planet like colorful belts and they move in opposite directions at around 600 km per hour. The collision of these horizontal cloud bands leads to giant storms.

The most famous giant storm on Jupiter is the Great Red Spot. This giant anticyclone is three times bigger than the Earth. It rotates counter-clockwise and has existed for 340 years. Since Jupiter is made only of gas, it doesn’t have a physical topography. Therefore, the storm can’t find a place to empty its energy. The winds around the Great Red Spot, which looks like a red oval eye, have a speed of 400 km per hour.

It’s still a matter of debate as to how the Great Red Spot reached such a giant size. Scientists have argued multiple theories. One theory states that this giant storm has been fed by an internal heat energy and engulfs all the other storms it comes across. As the hot gases that comprise Jupiter’s atmosphere rise from lower levels to higher levels, eddies form and converge. As cooler gas falls back to the planet’s surface, it causes a swirling motion. These eddies can last for a long time, because there is no solid surface to provide friction. Many adjacent eddies are engulfed and merge with the spot, adding to the energy of the storm and contributing to its longevity.

Other scientists mention that the Great Red Spot has begun to shrink. While the spot was about 41,000 km wide in the 1800s, it had shrunk to 23,300 km in 1979, according to the measurements of Voyager 1 and 2. Recent Hubble telescope measurements report the storm’s size as 16,500 km wide. Another large storm, whose diameter is as large as the Earth’s, was observed below the Great Red Spot.

Winds twice as fast as sound

During hurricanes and tornadoes, the winds on Earth are strong enough to demolish buildings. Yet if we spent a day on Neptune, where the fastest winds in the solar system occur, we wouldn’t be so impressed with the Earth’s winds. Winds on Neptune can reach speeds of 2400 km per hour. This is twice as fast as the speed of sound (1235.5 km per hour).

Astronomers think that freezing weather conditions may lead to the strong winds on Neptune. As on Jupiter, there is no friction to slow the currents down – though here the culprit is an icy planet, not a gaseous one. The fastest jet streams are visible as dark spots. The most important ones were the Great Dark Spot, located in the southern hemisphere, and the Small Dark Spot, which was south of the great dark spot.

The Great Dark Spot was an anticyclonic storm and was first discovered by Voyager 2 in 1989. It was about the same size as Earth, and was very cold and dark. There were silky cirrus clouds around the spot made up of crystals of frozen methane. However, the Great Dark Spot was not observed by the Hubble Space Telescope in 1994.

The Small Dark Spot, also called The Wizard’s Eye, was a southern cyclonic storm. It was also observed by Voyager 2. But again, when the Hubble observed Neptune in 1994, the storm had disappeared.

In lieu of these two storms, a new dark spot was discovered in the northern hemisphere. This storm, whose width is almost 2400 km, is still active. Apart from this storm, there are also speedy and comparatively small clouds called “scooters.”

When observed at a distance, Saturn and its giant rings seem quite taciturn. However, beneath the surface are rough storms like the Great White Spot, discovered in 1990, and the Giant Storm, discovered in 2010. Although cloud zones that are parallel to the equator are observed in Saturn’s atmosphere, the color and contrast between the bands are not as striking as on, say, Jupiter. In these neighboring zones the clouds move in opposite directions at enormous speed. White spots are observed when some of them interact, creating storms that can reach a truly gigantic size.

These storms can reach speeds of 1800 km per hour, making them the second fastest storms in the solar system after Neptune’s. The most striking storms on Saturn are those observed above the North Pole. These storms have an unusual hexagonal shape, which is due to atmospheric vortices in the polar regions. The biggest of these storms has a width of about 13,800 km. Once again, the existence of these huge storms was proved by Voyager 1 and Voyager 2 in 1980 and 1981.

In 2009, the Giant Storm was observed more closely thanks to NASA’s Cassini Spacecraft. As a result of these observations, it has been revealed that the Giant Storm has existed for 30 years and has winds estimated at 480 km/ph.

When we look at other planets in the solar system, Venus has dramatic differences between high and low pressure in its atmosphere. The planet is covered by thick, heavy clouds made of sulfuric acid. Venus is made of active volcanoes, which produce toxic gases and constant heat; the planet is literally shaped by toxic smoke.

Mars is famous for giant red dust storms that blanket the entire planet and last for months. When Mariner 9 arrived on Mars in 1971, it found out that the atmosphere was thick with “a planet-wide robe of dust.” The only visible object was Mount Olympus Mons, which is nearly three times taller than Mount Everest.

Upon observing the atmospheres of nearby planets, and the enormous storms that torment them, it’s hard not to contemplate the enormous power that exists in the universe – and we find ourselves grateful that Earth was created in such a temperate manner. Without such an amenable climate, life wouldn’t be possible.   

Ink heals,
Pen befriends.
Paper mirrors,
Words are interlocutor.
They are lost indeed
when you have no mirroring ear,
when the mirror is gone,
the paper torn;
to hear
makes the pen cry, and
only then ink is revealed.

O, Beloved Friend
Fill my hands with the ink
of your inspiring winds.
Let my eyes, right and left, see
none,
All You,
thus all.
Did you hear what happened?
Did you know how it happened?
Of course you do.
But I want to tell
because this is what you do:
you know, but again, the pleasure
is to listen.
And on my part
it is to tell.
I want to forget my forehead on the soil that stands before You, welcoming,
I want to forget nothing.
But I only become Zero
In that moment.

Let us imagine the earth as a small sphere before us. If we throw an object from the North Pole toward point A on the equator line, the object follows a curved line towards the right side and reaches point B, not point A. Likewise, an object thrown from the South Pole towards the same point A will follow a similar line curved in the opposite direction. These cases have a common point. An object rolling on a rotating ground moves on a curved line. This curved line, instead of a straight one, is explained with reference to the force of acceleration. This force is named after the French engineer, Coriolis who explained it in 1835. If this force-which is generated by the earth rotating around its own axis-did not exist, then air movements and ocean currents, and consequently the climate conditions of our world, would be different than they are. The objects in our example, thrown from the two poles, go in different directions, because the world rotates counter-clockwise when looked from the North Pole, and clockwise from the South Pole.

The air over the equator receives the sun’s rays at a broad angle. It rises up after gaining heat and is replaced by colder air coming from distant latitudes. Air convection begins in connection with these heat changes. So if the world did not rotate, the air on the Poles would get heavier with cold air and come down. Then, it would be replaced by hot air from lower latitudes. The air at the equator would rise up with gaining heat and would move until reaching the Poles where it would come down after losing heat. Then, it would return to the equator, this time very close to the ground. In this case, the world would probably be an uninhabitable place with cold and fierce winds blowing all around. And of course, the side facing the sun would be very hot and the other side would be very cold.

Instead, the Coriolis effect makes these great atmospheric air masses move over our rotating earth. The hot air rising up from the equator moves towards the poles with a curved course thanks to the Coriolis effect (Figure 4). As this air current approaches the latitudes around 30 degrees, it loses heat and descends. A part of the descending air begins to move back toward the equator, but it follows a curved line again owing to the Coriolis effect. So this last curving forms the “trade winds.” In the past, sailing ships traveled from Europe to America for the purpose of trade; thus, these winds were named as trade winds. This air circulation between the equator and the 30-degree meridians is known as Hadley circulation. These air currents cause heavy rainfall in the equatorial region and the consequent formation of rain forests, which are considered as the lungs of our planet, and also they cause the formation of deserts around the region where the dry and hot weather are pure blessings for us. They are a blessing because the airborne dust rising from the desert fertilizes the rainclouds and plays a critical role for rainfall.

The air over the poles becomes cold, and it causes another air current as it becomes heavier and starts to descend. As the lowered air moves toward the equator, it changes course with the Coriolis effect. At the same time it begins to gain heat and ascend. At the latitudes where water ascends by gaining heat, a rain climate prevails. This polar air cycle is seen between latitudes of 60-90 degrees.

Some part of the air current, which descends down around 30 degrees of latitude, moves toward the poles at a low level. Also, some part of the air which comes from the poles and ascends begins to move towards the equator. So a third air cycling begins between the altitudes between 30-60 degrees. The “western winds” are brought forth from this third cycle. During the time of sailing ships, these winds were used to traveling from America to Europe (Figure 4).

In order for these air cycles to happen, the earth’s rotation around its own axis is not sufficient; its speed and atmospheric mass also play an important role. If the earth rotated slower, the Coriolis Effect would be too weak to give way to a triple air cycle. For example, since Venus rotates too slowly, there is only a single air cycle in its atmosphere. Another factor, as we mentioned, is the mass of the atmosphere. Since the atmosphere of Mars is thin and its mass is relatively less, the Coriolis Effect is too weak and there is only a single air cycle.

Coriolis Effect prevents the air current from following a straight course and the isobars form twisters as they proceed. Therefore, hurricanes in the Northern hemisphere move counter-clockwise, and those in the south move clockwise (Figure 5). Naturally, these main atmospheric movements are not the only ones. A region’s climate is dependent on several factors such as landscape, night-day heat differences, and the like. Therefore, the climatic conditions on the earth have a very complex structure. Even when we consider just these few factors discussed here, it is evident that there are countless parameters that make human life possible in our planet, and each one is finely adjusted. Even slight changes in rotation and the mass of the atmosphere would result in a dramatically different planet Earth.

The ocean currents

Movement of air masses affects the water on the ocean surface as well. Thus, wind-generated surface currents are born. These currents are parallel with the relevant winds. It is a well-known fact that these huge bodies of water change the climate of the regions they pass. Therefore, two places at 54 degrees of latitude show a surprising difference: there can be a polar bears’ park in Ontario, whereas palm trees and tropical fruits can grow in Belfast thanks to the Gulf Stream. There are other warm ocean currents that pass from Brazil, and the north and south of the equator. Some of major cold surface currents pass from Labrador, Canada, the Falkland Islands, and Peru. Warm currents soften the climate of the regions they pass, while cold currents provide sea creatures with rich food, and they are important areas of fishing.

The impact of the wind on ocean water normally reaches as deep as 100-200 meters, and even 1,000 meters in some cases. The Coriolis effect has a determining role on the direction of the currents. These currents on the move make a turn when their way is blocked by land. Thus, the succession of ocean currents becomes a cycle, and they form the great current cycles named as “gyre.” They turn clockwise in the Northern Hemisphere and counter-clockwise in the south.

There are five main ocean circulations on earth and each of them consists of four streams. These currents are at the north and south of the Atlantic Ocean, the north and south of the Pacific Ocean, and one in the Indian Ocean. The North Atlantic circulation is made up of the Northern Equator Current, the Gulf Stream, North Atlantic Current, and the Canary Current.

With the Coriolis effect, a blessing of wondrous scale, food chains are brought to life in the ocean and around coastal regions. The ocean waters are set in motion by the winds generated by the Coriolis effect, but they do not strictly follow the winds that activated them. With a deflection of nearly 45 degrees they move right in the Northern Hemisphere and to left in the Southern Hemisphere.

The effect of the winds weakens in the deeper ocean waters, and then the Coriolis effect becomes dominant. Thus the direction of ocean water carried in the Northern Hemisphere is vertical to the wind direction and towards the right. This condition causes ocean waters to be pushed towards the circulatory center, and the water level there rises about 2 meters.

As rising waters move down with the effect of gravity, the Coriolis effect comes to the stage again to give way to another current in the same direction within that current. The waters that were rising toward the center begin to sink, and they form a new vertical current. For the same reason, the separation of the water current to the right and left directions around the equatorial regions gives way to the waters at the bottom which then come to the surface. At these places, the water level decreases a little. This “upwelling” phenomenon has very important results. Dead organisms sinking down are broken down by bacteria in the deep waters. When this nutrient-rich water returns to the surface, it is a great blessing for so many sea creatures. It is a striking fact that the rotating of the earth is a means for providing many living beings with sustenance. All of these finely adjusted balances on our planet, which we mostly take for granted, provide reflecting minds with food for thought.

Conventional water and wind turbines cannot function properly in a whirling current; the working of turbines depends on the existence of a steady and regular flow. In order to be able to obtain energy from vortices, turbines would need to mimic the movements of fish, adjusting their position to the differing angles of flow. A mechanical device to be developed in this respect should perceive the angle of the current flow instantly and adjust itself accordingly.

Normally, wind turbines are set up in high and open places. However, in cities the eddies that are formed by winds moving around buildings and roofs prevent conventional turbines from working efficiently. In order to overcome this challenge, scientists are aiming to develop turbines that benefit from the dynamic principles apparent in the movement of fish, though without imitating the fish exactly. They hope that in this way it will be possible to produce energy from turbulent currents as well. The projects being devised aim to develop different types of turbines to work in air and water. The energy production of these turbines will naturally be relatively low in comparison to common wind turbines operating in strong winds. However, these new types will make it possible to produce energy from winds moving at less than 32 feet per hour, when conventional turbines do not function. So, the total annual energy they are expected to produce will be no less than the regular wind turbines. If scientists can successfully model the admirable engineering applied in the bodies of fish, they will be able to boost the efficiency of these devices dramatically.

Notes

1. For further information see Liao J. C. et al., “Fish exploiting vortices decrease muscle activity,” Science 302, 1566–1569, 2003.
2. Dabiri, J. O., “Renewable fluid dynamic energy derived from aquatic animal location,” Bioinspiration and Biomimetics 2, L1-L3, 2007.

You would indeed have a lot to calculate before taking off: What is the most economical flight speed of your aircraft, and how does it vary with winds, flight altitude, and the extra weight of fuel reserves? Perhaps the gliding performance of your aircraft is good enough to permit you to travel some distances by soaring in up- draughts, with the engine off. It may even be economical to make detours in order to stay over regions with strong up-draughts. Would it be favourable to bring along large fuel reserves and fly non-stop for long distances without refuelling, or to travel by numerous short flights, saving transport costs for extra fuel? To solve that problem, you have to know about possible refuelling stations along your route, about petrol prices, landing fees, and the time delay you will face by landing at a particular site.

Which is the optimal route to your destination? Perhaps it pays to follow the Great Circle, or should you make a detour where you can benefit from favourable winds? Of course, you will fly only on days when the weather is as favourable as possible, but which is the best weather? And how can you know which weather condition is most favourable for you? What flight altitude will you prefer under different weather conditions? You must also consider whether and how you will compensate for wind drift, when to fly low along coast-lines and other leading-lines to gain protection from the wind and avoid drift, and how to exploit the winds at high altitudes. And you must also take into account many unpredictable situations that you will face. There are lots of questions and you would spend a long time looking up facts and making calculations before you could arrive at a reasonable strategy for your flight.

Your situation is analogous to that of migrating birds. The migratory strategy of birds, a harmonious mixture of rigid and flexible behaviour to achieve a safe and economical journey which can be affected by a bewildering number of factors, is an astonishing feat – where do they get the skills and capabilities to accomplish it?

There are many animals, not only birds, which migrate on a regular basis. Some examples: Bull elephant seals travel 21,000 km (over 12,000 miles) each year, from California to the Gulf of Alaska, the longest migration of any mammal. Millions of monarch butterflies fly 2,000-3,000 km from Canada to the Gulf of Mexico. Grey whales swim 10,000 km from the Arctic Ocean to California and Mexico. In Bracken Cave in Texas 20 million free-tailed bats assemble every summer. All are female. They leave their mates 1500 km to the south in Mexico to come here to give birth to their young. Herring migrate annually and cover over 3,000 km. The bison, the wildebeest, the sockeye salmon, the eel are also known to migrate long distances. But here we will consider the migration of birds – one of the most impressive feats in animal behaviour- across thousands of kilometres of ecological barriers, like oceans, mountains and deserts.

Birds store fat for use as fuel during their migratory flights. They start to do so well before migration starts. Stored fat is the most economical type of fuel in terms of high oxidizing energy per unit mass. Once the animal is in the right condition to migrate, it may need some further environmental cues to initiate the actual migratory movement. A bird may wait for the right weather conditions or at least the disappearance of the wrong ones, such as fog or very strong winds.

In order to locate its goal at a different position on the earth’s surface, an animal must possess certain sensory systems and have certain decision-making programmes in its behaviour. The ability to take up a particular direction with respect to some feature or property of the environment is called orientation’. The orienting animal is rather like a man who possesses a compass and an instruction to proceed in some particular direction. Animals may orient with respect to objects on the earth’s surface, to the sun, to the stars, to the earth’s magnetic field, to the directions of current flow and so on. Further, they may use more than one of these environmental sources of information at any one time, and may use different ones at different times.

Birds may use continuous flapping flight or soaring flight. Migration of soaring birds attracts much attention among bird-watchers because of spectacular concentrations of these migrants at passages with favourable soaring conditions. The migrants make long detours to avoid having to use flapping flight over the sea, and the sites most famous for soaring bird migration in Europe, Falsterbo, Gibraltar and the Bosphorus, are situated at minimal sea crossings. Migrants’ coasting behaviour probably is part of their ‘strategy’ to exploit winds and conserve energy at the same time. Coastal migration occurs mainly under opposed and cross-winds, while migrants usually fly across the coast and depart over the open sea with following winds. Due to differences in friction, winds generally are stronger over the sea than over land. Migrants minimize the headwind force by following the coast, where they can use local topography and vegetation to gain additional protection from the wind. Furthermore, over the sea they will be exposed to wind drift, and under certain cross-winds it is beneficial to follow a coastline, some distance in the direction of their goal, rather than to take a direct route over the sea.

Some birds travel by numerous short flights, each of about three to ten hours duration. Many species depart either by day or by night, whenever weather becomes favourable. Flying with a small load of fat is advantageous, since the labour costs for carrying the extra fat can be high. However, there are also drawbacks involved in migrating by numerous short flights: the birds have to refuel often and find suitable resting sites on their route.

Some species undertake enormous non-stop flights. A regular migration route from North to South America directly over the Western Atlantic Ocean, a distance between 3,000-4,000 km, is used by many species. Just to mention some examples of long, nonstop flights over oceans other than the Atlantic: there are some geese that fly almost 4,000 km across the Pacific Ocean from the Alaska Peninsula to the South Californian coast; two species of New Zealand cuckoos fly about 3,500 km to the Solomon and Samoa islands; passerines, bee-eaters and Amur falcons travel almost 3,000 km of the Indian Ocean between India and East Africa.

Many migrants fly between Europe and Africa across the Mediterranean Sea and the Sahara desert in one single non-stop flight, lasting at least 40 hours in the autumn, when winds are generally favourable, and 60 hours in spring when they are less favourable.

Honey buzzards migrate by cross-country soaring over a distance of 7000 km from Europe to tropical Africa without refuelling. Common buzzards cover a distance of 10000 km between East Europe/West Siberia and South Africa by soaring migration. Many young Manx shear waders, in their autumn flight from Britain to Brazil, cover almost 0,000 km without refuelling. Various water species wintering in South Africa cover the total distance to their high Arctic Eurasian breeding grounds, about 13,000 km, in four or so long flights.

Arctic terns are transglobal travellers on a scale unequalled by any other migrant. Some annually commute between the Northern and Southern pack ice, crossing the equator twice. The round trip must be at least 40,000 km (25,000 miles).

Low temperatures seem not to prevent birds from migrating at high altitudes, The highest migrants over Puerto Rico experience temperatures of about –12 C, and over Switzerland migration is perfectly regular at altitudes with temperatures around -IC to -15 C. In fact, the birds’ capacity to fly under conditions of low temperature and low oxygen pressure is so great as to be hardly credible: On 9 December 1967, a radar controller in Northern Ireland reported an echo at high altitude moving south over the Hebrides. The radar height finder indicated an altitude between 8,000 and 8,500 m. The pilot of an aircraft in the vicinity was asked by radio to make a course deviation to pass near the position of the echo. In doing so, the pilot reported a flock of about 30 swans at just over 8,200 m. The observation probably refers to whopper swans, which are known to migrate, sometimes in the middle of the winter; from Iceland to Britain. At 8,200 m, the temperature was -48 C and very strong northerly tailwinds blew at this altitude.

Although, according to some radar studies, probably 90% of birds travel below 2,000 m, two small flocks close behind each other of curlew-like birds were observed at I 0,000 m above sea level.

These observations, indeed, are extraordinary. One wonders, are such enormous flight altitudes merely exceptional or do some birds regularly migrate that high?

We tend to think of events which happen regularly, as ‘normal’ or ‘ordinary’. But are they really? Very often, we do not realize the dimensions of the events. Hundreds of millions of birds migrate from one place to another. Tens of thousands of birds start to fly together. They fly very long distances together and land and feed together. Many of them have never flown that long, nor been to those places. But still they are able to fight against all the odds and finish their journey How do they know when to start? How do they recognize the landscape? How do they decide which route to take? How do they find their way to their destination? How do they know where they can find food? How come so many birds can act together? How and when did they learn to use the sun and other stars, or the earth’s magnetic field, for navigation? How did they acquire the necessary means in the first place?

There are numerous such questions to ask and very often, it is not easy to find the right answers. When the other migrating animals are taken into account, the questions get more complicated and more challenging Hundreds of millions of animals migrate twice a year covering thousands of kilometres. We must ask questions which start with how and why and not take ‘ordinary’ events for granted.