Category Weather & Climate

            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.

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            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.

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            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.

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            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.

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            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.

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          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.

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          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.

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          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.

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