My Science School

            Most outdoor sports events can be affected by adverse weather conditions in one way or another. “Rain stopped play” is a phrase familiar to followers of cricket in England, where the often unpredictable summer weather regularly interrupts a game. Tennis is similarly affected when heavy rain makes play impossible on open-air grass courts. Some sports can be played in almost all weathers (only severe snow and freezing temperatures will stop a soccer or rugby match), but the conditions can influence tactics and the outcome of the game.

            The effects of weather on sport are varied, with some events unable to take place while others are changed considerably. The performance of participants can be reduced or improved, and some sporting world records are invalid if set under certain weather conditions. While outdoor sports are most affected, those played indoors can still be impacted by adverse or advantageous weather conditions.

            Temperature has a significant impact on the performance of athletes. High temperature can cause various heat illnesses such as heat cramps and heat stroke, while very low temperatures may lead to hypothermia.

             Some major sporting events cannot be held when the temperature is too high. When AFC selected Qatar as the host of the 2011 AFC Asian Cup they opted to run the event in the January window rather than July or August because they considered it to be "too hot in the Gulf region". However, the also set to be held in Qatar, is scheduled for the late fall and early winter.

            Some sports are cancelled because of precipitation. Some are deemed too dangerous to play when the ground is damp because of the danger of injury to a player through slipping.

            When the rain is excessive an event might be canceled because of a waterlogged pitch. Winter sports can sometimes be canceled due to the amount of snow on the ground, be it too little or too much.

            Wind can blow the equipment in a sporting event, changing the direction or travel of a ball. In golf the wind levels may influence the way a shot is taken.A headwind can slow runners, while they may gain wind assistance from a tailwind.Some sports rely on the presence of wind, especially surface water sports.

            Some sports cannot be played if there is insufficient visibility as it can make them dangerous or can be disadvantageous to a competitor. Cricket test matches often finish when the umpire decides that the light level is too low and the timing of this can sometimes be controversial. The difficulties of playing in bad light conditions is also disputed. Some events are called off when there is heavy fog.

Picture Credit : Google

            Farmers need to pay special attention to the weather in order to tend their crops or feed their animals. Knowledge of a severe frost or rain will influence the time that they sow seeds or harvest crops. Accurate weather forecasts also help farmers to decide when to treat crops with chemicals. For example, should it rain shortly after pesticides are applied, they will be washed away and have little effect — a waste of time and money for the farmer. Forecasts for farmers provide as much information as possible about the weather for the next week or so.

            Most people know that the weather has a significant impact on the agriculture industry. Indeed, crops need the basics of moisture, warmth, and sun to thrive. But what’s less obvious is how the details of weather information can drive a grower’s business decisions, helping them to plan efficiently, minimize costs and maximize yields—and profits—as a result.

             While farmers must make many day-to-day decisions related to weather conditions, there are four primary areas of farming that are fundamentally affected impacted by weather:

            Crop Growth/Irrigation: Crop growth, or crop yield, requires appropriate amounts of moisture, light, and temperature. Detailed and accurate historical, real-time and forecast weather information can help farmers better understand and track the growth status/stage to make informed decisions. Having access to this data can guide farmers in making significant and potentially costly decisions, such as whether, when and how much to irrigate.

            Fertilizer Timing and Delivery: One of the many decisions that farmers have to make is determining the proper time to apply fertilizer, as well as the application rate and fertilizer form to use. A misapplied application caused by weather can wipe away the entire field’s profits. Weather forecasts can be used to ensure that fertilizer is applied in the right conditions—when it’s dry enough so that it doesn’t wash away (which would create a waste of resources and money) but moist enough so that it gets worked into the soil.

            Pest and Disease Control: Certain weather conditions encourage the development and growth of pests and diseases, which can destroy crops. Forecast guidance incorporated into pest and disease modeling can help determine whether—and when—it’s appropriate to apply pest or disease controls. Wind forecasts also play a role in this decision, as crop dusters, aircraft that spray fungicidal or insecticidal chemicals on plants from above, must be utilized when wind conditions are not apt to cause sprayed chemicals to miss their targets.

Picture Credit : Google

            People who work at sea depend heavily on detailed, specialized weather forecasts because their lives can be at risk when stormy conditions bring high winds and steep seas. Fishermen may decide where to fish according to weather conditions, while sport sailors pay close attention to wind details to plan their racing tactics. All mariners listen to radio stations and coastguard broadcasts for advance warn-ings of weather conditions, which focus on the speed and direction of the wind, visibility and barometer readings.

            We receive weather information every day in a variety of ways – through television, radio, on our smartphones and through conversations around the water cooler. But how do you get weather forecasts on the high seas where WiFi is rarely an option? Across our oceans, NOAA’s Ocean Prediction Center (OPC) is delivering critical weather forecasts to keep you safe – at sea.

           Did you know 11 million Americans travel on cruise ships each year, and that our nation’s maritime shipping industry - the way we primarily receive goods from other countries - is a 1.5 trillion dollar economic activity annually for the U.S? This means accurate and reliable weather forecasts at sea are an incredibly important part of our nation’s economy.

            Every day, expert weather forecasters at OPC deliver more than 150 different products - like forecasting maps and guidance - for weather events across the Atlantic and Pacific Ocean basins, including the waters around Alaska. This forecast guidance makes its way into the hands of commercial shipping vessels allowing ship captains to dodge hurricanes, cruise ships to route around nor’easters and recreational boaters to return home safely.

            Hazards at sea can vary greatly and OPC forecasts for all of them. High winds, large waves, thunderstorms, sea ice, freezing spray, and volcanic ash all present significant safety issues to mariners traveling with precious cargo- the lives of their passengers and crew.

            Even with these challenges, OPC delivers life-saving forecasts around the clock each day, while also working hard to modernize the ways they provide forecasts to a geographically diverse community. And OPC has some great partners. OPC forecasters collaborate closely with the U.S. Coast Guard, the U.S. Navy and the international maritime community to continually advance services and ensure critical forecasts reach those who rely on them to make safety decisions at sea.

Picture Credit : Google

            Some experts believe that when glaciers melted 7000 years ago, this caused the Mediterranean to overflow into the Black Sea, then a small freshwater lake. This may form the basis of Middle Eastern tales, such as the one recorded in the Old Testament, of a hugely destructive flood.

           A flood of Biblical proportions just like in the story of Noah's Ark may have actually happened, according to the oceanographer who found the Titanic.

            Acclaimed underwater archaeologist Robert Ballard claims his team of researchers have uncovered evidence that suggests The Great Flood described in the Bible was actually based on real events.

            Mr Ballard told how he investigated a controversial theory proposed by two scientists from Columbia University that there was a massive flood in the Black Sea region.

           In an interview with ABC News, he said around 12,000 years ago much of the world was covered in ice and the Black Sea had been a freshwater lake surrounded by farmland.

            But when the glaciers began to melt during a warming period in the cycle of the Earth's temperature around 5600BC water rushed toward the world's oceans, Mr Ballard said. This, he claimed, caused floods all around the world and water cascaded through Turkey’s Straits of Bosporus towards the Black Sea.

Picture Credit : Google

            Weather forecasts are used by everybody, but some people pay closer attention to them than others. Severe weather conditions can endanger lives on the roads, at sea and in the air, so transport and safety organizations are regularly updated on the weather situation. Many businesses, from farming and fishing to hotels and restaurants can be affected by the weather, so a forecast can help with business planning.

            This chapter examines recent and expected developments in the scientific capability to make seasonal-to-interannual climate forecasts and discusses the types of forecasts that are likely to be socially useful. As background for readers unfamiliar with climate forecasting, we begin by discussing the distinction between weather and climate and how climate forecasts are made.

            We are all familiar with the progression of the weather. Every few days, the temperature changes, rain comes and goes, or a severe storm hits. The characteristic time scale for changes in weather in the mid-latitudes is a few days or less. In the tropics, especially over the ocean, the weather tends to be much steadier, with sunny weather and steady trade winds punctuated by an hour of daily downpour (usually in the late afternoon) or by a squall every few days.

Picture Credit : Google

          The river Nile was the source of life and prosperity in Egypt. The Ancient Egyptians relied on the annual floods of the Nile to irrigate their crops, but studies have shown that the way in which the river floods varies considerably. Working together, historians and climatologists have found links between years of low flooding and periods of instability in Egyptian society. Records show that the famines that followed low floods led to disease and civil unrest — possibly causing the collapse of the Old Kingdom.

          The flooding of the Nile is the result of the yearly monsoon between May and August causing enormous precipitations on the Ethiopian Highlands whose summits reach heights of up to 4550 m (14,928 ft). Most of this rainwater is taken by the Blue Nile and by the Atbarah River into the Nile, while a less important amount flows through the Sobat and the White Nile into the Nile. During this short period, those rivers contribute up to ninety percent of the water of the Nile and most of the sedimentation carried by it, but after the rainy season, dwindle to minor rivers.

          These facts were unknown to the ancient Egyptians who could only observe the rise and fall of the Nile waters. The flooding as such was foreseeable, though its exact dates and levels could only be forecast on a short term basis by transmitting the gauge readings at Aswan to the lower parts of the kingdom where the data had to be converted to the local circumstances. What was not foreseeable, of course, was the extent of flooding and its total discharge.

          The Egyptian year was divided into the three seasons of Akhet (Inundation), Peret (Growth), and Shemu (Harvest). Akhet covered the Egyptian flood cycle. This cycle was so consistent that the Egyptians timed its onset using the heliacal rising of Sirius, the key event used to set their calendar.

          The first indications of the rise of the river could be seen at the first of the cataracts of the Nile (at Aswan) as early as the beginning of June, and a steady increase went on until the middle of July, when the increase of water became very great. The Nile continued to rise until the beginning of September, when the level remained stationary for a period of about three weeks, sometimes a little less. In October it often rose again, and reached its highest level. From this period it began to subside, and usually sank steadily until the month of June when it reached its lowest level, again. Flooding reached Aswan about a week earlier than Cairo, and Luxor 5 – 6 days earlier than Cairo. Typical heights of flood were 45 feet (13.7 metres) at Aswan, 38 feet (11.6 metres) at Luxor (and Thebes) and 25 feet (7.6 metres) at Cairo.

Picture Credit : Google

          1200 years ago, the Mayan civilization thrived in what are now southern Mexico, Belize and Guatemala. The Mayans were brilliant astronomers and mathematicians, and their society was very stable and established. However, at some point during the 9th century, their civilization suffered a sudden and devastating collapse. Archaeologists have struggled to find an explanation for the Mayans' fate, but recent studies suggest that a massive drought was responsible. Analysis of mud samples from the bottom of Lake Chichancanab in the Yucatan area of Mexico has found that the region's climate in the 9th century was the driest that it had been for 7000 years.

           The Maya civilisation, which dominated southern Mexico for hundreds of years, appears to have been brought to its knees at least in part by a series of severe, decades-long droughts, scientists say. Conditions were so bad, says Nicholas Evans, a geochemist at the University of Cambridge, UK, that rainfall decreased by 50% on average. During the worst periods, he says, it decreased by up to 70%. The drought was further exacerbated by a 2-to-7% drop in relative humidity, his team found.

          The climate shift coincided with an era called the Terminal Classic Period, between 800 and 1000 CE, when the Maya civilisation was in decline and permanently abandoned many of its cities. The idea that drought may have contributed to this collapse isn’t new. “[It] has been debated for at least 100 years,” says Christopher Baisan, a dendrochronologist, or tree-ring scientist, at the US University of Arizona’s Laboratory of Tree-Ring Research, who was not involved in the new study.

          But just how severely the climate had changed was not clear. All that was really known was that it was drier than at the height of Maya influence. Evans’ team took core samples of sediments in a lake in the central Yucatan peninsula. “These sediments contain muds,” Evans says, “but importantly, they also contain a mineral known as gypsum.”

          Gypsum is a crystal that precipitates out of water when the mineral content grows too large — something that can occur during a drought. It is predominately composed of calcium and sulfate, but it also includes trapped water molecules.

          By examining hydrogen and oxygen isotopes in these molecules and comparing them to water in lake today, Evans says, scientists can chart changes in the lake. From these, he says, it’s possible to deduce variations in rainfall patterns.

          The result isn’t perfect. To begin with, gypsum only forms during periods of drought, when minerals become concentrated enough to precipitate to the bottom. Also, the isotope levels of the trapped water reflect multi-year averages of climate conditions in and around the lake, not an instantaneous measure.

Picture Credit : Google

          Three years after his retreat from Russia, Napoleon faced the allied forces of Britain and Prussia at Waterloo. Again, the weather was to play its part. Very heavy rain in the region made the ground muddy, which delayed Napoleon's attack. The delay meant that the allies, under the leadership of the Duke of Wellington, were able to send in additional troops and supplies, which ultimately helped them to victory.

          Two months before Napoleon's historic defeat at Waterloo, a volcanic eruption in Indonesia caused heavy rains in Europe that soon succeeded in bringing him down.

          The defeat of French emperor Napoleon Bonaparte at the Battle of Waterloo in 1815 is widely believed to be due to the inclement weather in England. But a new study suggests that Napoleon’s misfortune with the rain and mud was caused by a massive volcanic eruption in Indonesia two months prior to the battle.

          On the night before Napoleon’s final battle, heavy rains flooded the Waterloo region of Belgium and as a result, the French Emperor elected to delay his troops. Napoleon was worried that the soggy ground would slow down his army.

          While that might have been viewed as a wise choice on Napoleon’s part, the extra time allowed the Prussian Army to join the British-led Allied army and help defeat the French. 25,000 of Napoleon’s men were killed and wounded, and once he returned to Paris, Napoleon abdicated his rule and lived the rest of his life in exile on the remote island of Saint Helena.

          And none of that may have happened if not for one of the largest volcanic eruptions in history. The eruption of Mount Tambora could be heard from up to 1,600 miles away with ash falling as far as 800 miles away from the volcano itself. For two days after the explosion, the 350-mile region that surrounds the mountain was left in pitch darkness.

Picture Credit : Google

 

          Napoleon Bonaparte was one of the finest military leaders in history. His clever tactics brought a series of victories that allowed him to rule over large parts of Europe over 200 years ago. However, it was the weather that was to prove instrumental in his downfall. He invaded Russia in the summer of 1812 and captured Moscow, following the Russians deeper into the country. By November, a lack of supplies forced Napoleon and his army to retreat, and the extremely harsh winter killed many thousands of troops as they returned to France.

          In the year 1812, the infamous Napoleon assembled the largest army Europe had ever seen, more than 600 000 men strong. His plan was to march into Russia, and his last concern was the approaching winter chills. Napoleon confidently captured Moscow; his soldiers pillaged the city, stealing jewels, furs, and war prizes. However, it was too soon to be celebrating – since Napoleon had failed to consider how very cold Russia can be. As Napoleon’s army marched away with their prizes, temperatures dropped to minus 40 degrees Celsius. Many soldiers died of frostbite and starvation, and in one 24-hour period 50 000 horses died from the cold – leaving men to struggle on foot through the icy environment. Even with their stolen furs to wrap themselves up in – of the 600 000 men who marched into Russia, only 150 000 limped home. This was the beginning of the end for Napoleon’s empire, and heralded the emergence of Russia as a power in Europe.

Picture Credit : Google

          Throughout history, the weather has had a major influence on the outcome of certain events. Adverse weather conditions have helped decide the outcome of battles and military campaigns, while over longer periods of time, climate change is thought to have brought about the end of some civilizations and the beginning of others.

          While searching for some topic of interest to bumble on about in this blog, I remembered an article I read ages ago that left an impression. Maybe the weather is something that most of us at CSAG think about on a daily basis (I hope), but it is interesting to hear how the weather has helped shaped history – and thus the societal world we live in.  As will be discussed shortly, the weather can be a huge deciding point in what happens when, and it is interesting to hear about events that may or may not have happened because of weather conditions (and I’m not talking about a picnic at Kirstenbosch event).

          On the 6th August 1945 it was a fine summer day in Hiroshima. At 7:09am a weather reconnaissance plane passed overhead and radioed back: “Cloud cover less than three-tenths. Advice: bomb primary.” Thus, the sky was clear enough to drop the first nuclear weapon used in war. The lack of cloud cover sealed Hiroshima’s fate, and spared the back-up target. Even more dramatic was the effect of cloud cover on Kokura. On the 8th August 1945, the second nuclear weapon was loaded into a B-29, however the skies were overcast over the primary target, Kokura. Instead, the bomb was released over the backup target: Nagasaki.

          In the 13th century, Kublai Khan, leader of the Mongol Empire, set his sights on the conquest of Japan, but was defeated by not one, but two monsoons. Shinto priests, who believed the storms were the result of prayer, called them kamikaze or “divine wind.”

Picture Credit : Google

          The damage caused to crops by large hailstones has prompted many attempts to prevent hail forming. Techniques similar to those used in cloud seeding have been tried, aiming to turn hailstones into rain, but this does not seem to work. In the early 20th century, people tried using “anti-hail guns”. These would fire huge amounts of debris into the clouds in an attempt to break up the hailstones. They were tried many times, unsuccessfully, in the vineyards of France.

          A Hail cannon is a shock wave generator claimed to disrupt the formation of hailstones in the atmosphere.

          These devices frequently engender conflict between farmers and neighbors when used, because they are repeatedly fired every 1 to 10 seconds while a storm is approaching and until it has passed through the area, yet there is no scientific evidence for their effectiveness.

          In the French wine-growing regions, church-bells were traditionally rung in the face of oncoming storms and later replaced by firing rockets or cannons.

          A mixture of acetylene and oxygen is ignited in the lower chamber of the machine. As the resulting blast passes through the neck and into the cone, it develops into a shock wave. This shock wave then travels at the speed of sound through the cloud formations above, a disturbance which manufacturers claim disrupts the growth phase of hailstones.

          Manufacturers claim that what would otherwise have fallen as hailstones then falls as slush or rain. It is said to be critical that the machine is running during the approach of the storm in order to affect the developing hailstones, although all manufacturers unanimously agree that the area of effect of their device is only 100 to 200 square meters directly above.

Picture Credit : Google

          The next generation of lightning conductor could be a type of laser gun. A laser beam fired from the ground into a storm cloud could charge the air molecules along the way, creating a path for the lightning bolt to follow. Once the lightning is set on a direct path, its charge can be neutralized. It is thought that such a device could be used to steer lightning away from exposed structures such as power lines.

          Thousands of lightning bolts strike the Earth’s surface roughly every couple of seconds, but despite their ubiquity, this phenomena is somewhat poorly understood. Lightning is also unpredictable. While humans have been placing lightning rods for centuries to increase the probability of striking in a certain fixed point, its path cannot be controlled. That may be true in nature, but in the confinement of a lab of the INRS Energie Materiaux Telecommunications research centre (Varennes, QC, Canada), scientists have defied this common knowledge and used lasers to coax lighting to follow a predefined path.

          Lighting is one of the most powerful forces found in nature (if one single lightning strike was harnessed, the energy would power an entire home for a whole week), but at its core we can say that lightning is nothing but a discharge of static electricity. What we know from static electricity is that these discharges are caused by separation of charges into positive and negative ions.  Over time more of one charge builds until its natural attraction to the opposite charge causes it to migrate in an electrical discharge. In the case of lightning, the charge is built up in water.

          So, when you discharge static electricity between two tiny electrodes that’s basically a mini lightning strike – a couple of million volts short of the real deal discharged in thunder clouds. Electric arcs are used for all kinds of applications, from things as simple as ignition in a vehicle, to pollution control, to micromachining. Now, if you could also control the path of electric arc, then a slew of other potential applications could open up.

          One first baby step was made by the team at Advanced Laser Light Source facility, INRS. Their experiment was based on the self-healing properties of certain laser beams. When a laser beam is obstructed by an object, it can sometimes reconstruct its intensity once past the object. Using various laser shapes, like Airy beams and Bessel beams, the researchers guided electrical discharges and effectively controlled the path of mini lightning bolts, as described in Science advances.

          “Our fascination with lightning and electric arcs aside, this scientific discovery holds out significant potential and opens up new fields of research,” said Yves Begin, vice dean of research and academic affairs  at INRS. “This spectacular proof of concept, which was conducted over a distance of a few centimetres, required the high-power lasers, state-of-the-art facilities, and extraordinary research environment that our professors helped to create at INRS. Being able to work in such cutting-edge labs enables our students and postdoctoral fellows to embark on the path of scientific discovery even while still in school.”

Picture Credit : Google

 

          Scientists believe that it may be possible to "kill" a tornado. Space satellites could be used to fire beams of microwave energy towards the base of a thunderstorm. The theory is that this would heat up the cool downdraft of air that helps create the tornado, effectively knocking it out. This sounds very much like science fiction, and many scientists claim that it could never work.

          The most intense tornadoes emerge from what are called supercell thunderstorms. For such a storm to form, you first "need the ingredients for a regular thunderstorm," says Brooks. Those ingredients include warm moisture near the surface and relatively cold, dry air above. "The warm air will be buoyant, and like a hot-air balloon it will rise," says Brooks.

          A supercell requires more: winds that increase in strength and change direction with height. "Then the updraft tends to rotate, and that makes a supercell," explains Brooks. The supercell churns high in the air and, in about 30 percent of cases; it leads to the formation of a tornado below it. This happens when air descending from the supercell causes rotation near the ground.

          Even then, "we still don't know why some thunderstorms create tornadoes while others don't," tornado-chaser Tim Samaras said in early 2013. Samaras was a scientist and National Geographic grantee who was killed by a twister on May 31, 2013, in El Reno, Oklahoma.

          Brooks says scientists believe strong changes in winds in the first kilometer of the atmosphere and high relative humidity are important for the formation of tornadoes. He adds that there also needs to be a downdraft in just the right part of the storm.

          Tornado formation also requires a "Goldilocks" situation, in which air must be cold but not too cold. It should be a few degrees more frigid than surrounding air, Brooks says.

          He adds, "We don't understand how tornadoes die: Eventually the air gets too cold and it chokes off the inflow of new air into the storm, but we don't know the details."

Picture Credit : Google

 

          Cloud seeding is a scientific process that makes clouds produce rain and snow. It works by sending tiny particles of silver iodide, or other substances such as dry ice or liquid propane, into rain-bearing clouds, usually by aircraft. These substances stimulate the production of rain by providing something for water droplets to freeze on to — scientists call them ice nuclei. Once enough of the droplets take hold, they become heavy enough to fall to the ground. Cloud seeding cannot produce clouds — it can only make existing clouds produce rain.

          Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation that falls from clouds by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. The usual intent is to increase precipitation (rain or snow), but hail and fog suppression are also widely practised in airports where harsh weather conditions are experienced. Cloud seeding also occurs due to ice nucleators in nature, most of which are bacterial in origin.

          The most common chemicals used for cloud seeding include silver iodide, potassium iodide and dry ice (solid carbon dioxide). Liquid propane, which expands into a gas, has also been used. This can produce ice crystals at higher temperatures than silver iodide. After promising research, the use of hygroscopic materials, such as table salt, is becoming more popular.

          In mid-altitude clouds, the usual seeding strategy has been based on the fact that the equilibrium vapor pressure is lower over ice than over water. The formation of ice particles in supercooled clouds allows those particles to grow at the expense of liquid droplets. If sufficient growth takes place, the particles become heavy enough to fall as precipitation from clouds that otherwise would produce no precipitation. This process is known as "static" seeding.

          Seeding of warm-season or tropical cumulonimbus (convective) clouds seeks to exploit the latent heat released by freezing. This strategy of "dynamic" seeding assumes that the additional latent heat adds buoyancy, strengthens updrafts, ensures more low-level convergence, and ultimately causes rapid growth of properly selected clouds.

          Cloud seeding chemicals may be dispersed by aircraft or by dispersion devices located on the ground (generators or canisters fired from anti-aircraft guns or rockets). For release by aircraft, silver iodide flares are ignited and dispersed as an aircraft flies through the inflow of a cloud. When released by devices on the ground, the fine particles are carried downwind and upward by air currents after release.

          An electronic mechanism was tested in 2010, when infrared laser pulses were directed to the air above Berlin by researchers from the University of Geneva. The experimenters posited that the pulses would encourage atmospheric sulfur dioxide and nitrogen dioxide to form particles that would then act as seeds.

Picture Credit : Google