ACTIVITY 2

1. History of Meteorology and Invention of Weather Instruments.

2. Introduction In Bible times the forecasting of weather conditions was based solely upon observations of the sky. This is alluded to in the Bible book of Matthew where Jesus says to the religious leaders of the 1st Century, "˜You are able to interpret the appearance of the sky but the sign of the times you cannot interpret.' This method of simple observation prevailed until 1643 when Italian physicist Evangelista Torricelli invented the barometer. This simple device was able to measure the pressure of the air. Torricelli noticed that air pressure changes in accordance with changes in the weather. In fact a drop in pressure would often signal that a storm was coming. Atmospheric humidity was also able to be measured when the hygrometer was invented in 1644. Then in 1714 German physicist Daniel Fahrenheit developed the mercury thermometer. It was now possible to accurately measure the weather.

3. History of Meteorology It was in 1765 that daily measurements of air pressure, moisture content, wind speed and direction began to be made. This was first done by French scientist Laurent Lavoisier who stated, "With all of this information it is almost always possible to predict the weather one or two days ahead with reasonable accuracy." However things were not as simple as Lavoisier had thought. In 1854 a French warship and 38 merchant vessels sank in a fierce storm off the Crimean port of Balaklava. The director of the Paris Observatory was asked to investigate the disaster. On checking meteorological records it was seen that the storm had actually formed two days previous to the sinking's and had swept across Europe from the southeast. If a tracking system had been in place the ships could have been warned of the pending danger. As a result of these findings a national storm warning service was set up in France. This is recognized as the start of modern meteorology.

4. In the mid 1800s there was still no quick way of transferring weather data from one location to the next. Often the weather that was being warned about would arrive before the data did. That was until Samuel Morse invented his electric telegraph to allow speedy transference of information. Morse's invention now made it possible for the Paris Observatory to begin publishing the first modern weather maps. By 1872, Britain's Meteorological Office had followed suit. From then on the acquiring of weather data became more and more complex, as did the resulting meteorological maps. New graphic devices were developed to convey more information. Isobars, for example, were invented - lines drawn to link points that have the same barometric pressure. Isotherms connect locations that have the same temperature. Other graphic devices were also developed - symbols to show wind direction and force, as well as lines that depict the meeting of warm and cold air masses.

5. In the 20th century much sophisticated meteorological equipment has also been developed. Today, weather stations release balloons that carry what are called radiosondes. These are instruments that can measure atmospheric conditions and then radio the information back to the station. Of course, weather stations today also use radar. In 1960 the world's first weather satellite, TIROS 1 was sent into space equipped with a TV camera. Today, weather satellites orbit the earth from pole to pole. Geostationary satellites stay in a fixed position above the earth and constantly monitor one part of the globe.

6. The forecasting of the weather took a leap forward when, shortly after World War One, British meteorologist Lewis Richardson stated that since the atmosphere follows the laws of physics, it is possible to use mathematical calculations to predict future weather conditions. His formulas, however, were so complicated that the weather would be upon him before he could figure out what it would be. His calculations also only allowed for weather readings taken at six hourly intervals. However, with the advent of computers, it became possible to work out Richardson's lengthy calculations quickly. A complex numerical weather model was now established that incorporated all the known physical laws governing the weather. The equations are utilized in the following way: meteorologists divide the earth's surface into a grid with grid points spaced 80 kilometers apart. The atmosphere above each square is called a box and observations of atmospheric wind, air pressure, temperature and humidity are recorded at 20 different levels of altitude. A computer than analyzes the data received from the more than 3,500 observation stations around the world and produces a forecast of what the world's weather will be for the next 15 minutes. Then a forecast for the next 15 minutes is produced. Repeating this process a computer can produce a six day world forecast in just 15 minutes.

7. To achieve even greater accuracy the British Meteorological Office has what is called the Limited Area Model which covers just the North Atlantic and European sectors. It's grid points are spaced at intervals of just 50 kilometers. However, the formulas used and the results achieved are only approximate descriptions of the behavior of the atmosphere. To achieve more accuracy the skills of the weather forecaster must come into play. The forecaster must use his skills and experience to decide what value to place on the data he receives. As an example, when air cooled by the North Sea moves over the European land mass, a thin cloud layer often forms. Whether this cloud layer means rain is on the way in continental Europe the next day or whether it simply evaporates in the sun's heat depends on a temperature difference of only a few tenths of a degree. It is up to the forecaster to predict which will be the case.

8. Invention of Weather Instruments.

9. Introduction Measuring the Weather In the early days of the Weather Bureau numerous clever mechanical devices were invented to measure and record any and every meteorological (weather) parameter conceivable: ombroscope or rainfall recorder, mechanical anemometer or wind speed indicator, remote readout wind vane, pole star recorder.

10. ANEMOMETER Wind velocity or speed is measured by a cup anemometer, an instrument with three or four small hollow metal hemispheres set so that they catch the wind and revolve about a vertical rod. An electrical device records the revolutions of the cups and calculates the wind velocity. The word anemometer comes from the Greek word for wind, "anemos.“ Mechanical Anemometer In 1450, the Italian art architect Leon Battista Alberti invented the first mechanical anemometer. This instrument consisted of a disk placed perpendicular to the wind. It would rotate by the force of the wind, and by the angle of inclination of the disk the wind force momentary showed itself. The same type of anemometer was later re-invented by Englishman Robert Hooke who is often mistakenly considered the inventor of the first anemometer. The Mayans were also building wind towers (anemometers) at the same time as Hooke. Another reference credits Wolfius as re-inventing the anemometer in 1709. Hemispherical Cup Anemometer The hemispherical cup anemometer (still used today) was invented in 1846 by Irish researcher, John Thomas Romney Robinson and consisted of four hemispherical cups. The cups rotated horizontally with the wind and a combination of wheels recorded the number of revolutions in a given time. Want to build your own hemispherical cup anemometer Sonic Anemometer A sonic anemometer determines instantaneous wind speed and direction (turbulence) by measuring how much sound waves traveling between a pair of transducers are sped up or slowed down by the effect of the wind. The sonic anemometer was invented by geologist Dr. Andreas Pflitsch in 1994.

11. BAROMETER Barometer - Pronunciation: [b u rom´ u t u r] - a barometer is an instrument for measuring atmospheric pressure. Two common types are the aneroid barometer and the mercurial barometer (invented first). Evangelista Torricelli invented the first barometer, known as the "Torricelli's tube". The Barometer It was Galileo that suggested Evangelista Torricelli use mercury in his vacuum experiments. Torricelli filled a four-foot long glass tube with mercury and inverted the tube into a dish. Some of the mercury did not escape from the tube and Torricelli observed the vacuum that was created. Evangelista Torricelli became the first scientist to create a sustained vacuum and to discover the principle of a barometer. Torricelli realized that the variation of the height of the mercury from day to day was caused by changes in the atmospheric pressure. Torricelli built the first mercury barometer around 1644. Lucien Vidie - Aneroid Barometer In 1843, the French scientist Lucien Vidie invented the aneroid barometer. A aneroid barometer "registers the change in the shape of an evacuated metal cell to measure variations on the atmospheric pressure." Aneriod means fluidless, no liquids are used, the metal cell is usually made of phosphor bronze or beryllium copper.

12. HYGROMETER Hygrometer By Mary Bellis A hygrometer is an instrument used to measure the moisture content or the humidity of air or any gas. The best known type of hygrometer is the "dry and wet-bulb psychrometer", best described as two mercury thermometers, one with a wetted base, one with a dry base. The water from the wet base evaporates and absorbs heat causing the thermometer reading to drop. Using a calculation table, the reading from the dry thermometer and the reading drop from the wet thermometer are used to determine the relative humidity. Other kinds of hygrometers use human hair (blond) to determine moisture content. These are called mechanical hygrometers, based on the principle that organic substances ( human hair) contract and expand in response to the relative humidity. The contraction and expansion moves a needle guage. In 1783, Swiss physicist and geologist, Horace Bénédict de Saussure built the first hygrometer using a human hair to measure humidity. Some hygrometers use the measurements of changes in electrical resistance, using a thin piece of lithium chloride or other semiconductor devices and measuring the resistance which is affected by humidity. Leonardo da Vinci built the first crude hygrometer in the 1400s. Francesco Folli invented a more practical hygrometer in 1664. Robert Hooke Robert Hooke invented the universal joint, the iris diaphragm, and an early prototype of the respirator; invented the anchor escapement and the balance spring, which made more accurate clocks possible, invented or improved meteorological instruments such as the barometer, anemometer, and hygrometer; and so on. John Frederic Daniell In 1820, British chemist and meteorologist, John Frederic invented a dew-point hygrometer, which came into widespread use. Daniel is best known for inventing the Daniell cell, an improvement over the voltaic cell used in the early history of battery development.

13. RAIN GAUGE One source has is that the son of King Sejong the Great, who reigned the Choson Dynasty from 1418 to 145, invented the first rain gauge. King Sejong sought ways to improve agricultural technology to provide his subjects with adequate food and clothing. In improving agricultural technology, Sejong contributed to the sciences of astronomy and meteorology (weather). He invented a calendar for the Korean people and ordered the development of accurate clocks. Droughts plagued the kingdom and King Sejong directed every village to measure the amount of rainfall. His son, the crown prince, later called King Munjong, invented a rain gauge while measuring rainfall at the palace. Munjong decided that instead of digging into the earth to check rain levels, it would be better to use a standardized container. King Sejong sent a rain gauge to every village, and they were used as an official tool to measure the farmer's potential harvest. Sejong also used these measurements to determine what the farmer's land taxes should be. The rain gauge was invented in the fourth month of 1441. The invention of the rain gauge in Korea came two hundred years before inventor Christopher Wren created a rain gauge (tipping bucket rain gauge circa 1662) in Europe.

14. THERMOMETER What is a Thermometer? Thermometers measure temperature, by using materials that change in some way when they are heated or cooled. In a mercury or alcohol thermometer the liquid expands as it is heated and contracts when it is cooled, so the length of the liquid column is longer or shorter depending on the temperature. Modern thermometers are calibrated in standard temperature units such as Fahrenheit or Celsius. Early History The first thermometers were called thermoscopes and while several inventors invented a version of the thermoscope at the same time, Italian inventor SantorioSantorio was the first inventor to put a numerical scale on the instrument. Galileo Galilei invented a rudimentary water thermometer in 1593 which, for the first time, allowed temperature variations to be measured. In 1714, Gabriel Fahrenheit invented the first mercury thermometer, the modern thermometer. Thermometer At the start of the seventeenth century there was no way to quantify heat.SantorioSantorioSantorioinvented several instruments, a wind gauge, a water current meter, the "pulsilogium," and a thermoscope, a precursor to the thermometer. Santorio was the first to apply a numerical scale to his thermoscope, which later evolved into the thermometer.

15. CLOUDS Englishman, Luke Howard gave clouds their common names. Before 1800, observers spoke of clouds only as "essences" floating in the sky. Clouds had no names and were not well understood. Luke Howard noted that there are three basic shapes to clouds: heaps of separated cloud masses with flat bottoms and cauliflower tops, which he named cumulus Latin for heap; layers of cloud much wider than they are thick, like a blanket or a mattress, which he named stratus Latin for layer; wispy curls, like a Childs hair, which he called cirrus Latin for curl. To clouds generating precipitation, he gave the name nimbus Latin for rain. Cloud Formations Clouds are found in three layers in the lower atmosphere. Thus, with four types of clouds and three layers, we come up with 12 major cloud types that have evolved from Luke Howard's pioneering work. Heaps - Cumulus family clouds Fair weather cumulus Swelling cumulus Cumulus congestus Layers - Stratus family clouds Stratus altostratus cirrostratus Layered Heaps clouds stratocumulus altocumulus cirrocumulus Precipitating clouds cumulonimbus cirrus nimbostratus