The rain gauge is probably the oldest meteorological instrument.

The first measurements of rainfall amount were made in the orient, where reference was made in rainfall readings in a work called The Science of Politics by Chanakya, a minister of Chandragupta, who ruled India from 321 to 296 BC’

Rainfall measurements were also made in and around Palestine nearly 2000 years ago.

The son of King Sejong the Great, who reigned the Choson Dynasty from 1418 to 1445, is credited with inventing 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. 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.

Benedetto Custelli (1577 – 1643), a student of Galilio, is credited with originating the modern rain gauge in about 1639.

Robert Hooke, who discovered the law of elasticity and designed several meteorological instruments, made a rain gauge he called an ombrometer, derived from the Greek word ‘ombros’ and from which we get the word for an umbrella.

The basic design of the rain gauge has been the same for the past 350 years, but some have had square rather than round funnels and the sizes have varied.

 Keeping a weather eye open for wind vanes is an interesting pastime. In many countries of the world the tops of buildings are adorned with wind vanes. Weathervane is perhaps not the best word to use, for a vane just indicates wind direction and not weather. The word vane comes from the Anglo-Saxon word ‘fane’ meaning ‘flag’.

In the days of old sailing ships a narrow pennant was flown at the masthead to indicate wind direction to the helmsman and this was known as a vane. Today, sailing yachts use burgees for the same purpose.

The Tower of the Winds in Athens once bore on its roof a wind vane in the form of a bronze Triton holding a a rod in his outstretched hand, rotating as the wind changed direction. Below, the frieze was adorned with the eight deities. The eight metre high structure dates from around 50 BC.

The wind vane evolved from a Triton to a weathercock as the Roman Empire converted to Christianity. Many churches have a weathercock on the tower or spire.

Pope Nicholas 1 in the ninth century ordained all land vanes to be in the shape of a cockerel to remind people of Peter’s denying Christ and the cock- crow that followed. Hence the commonly used synonym weathercocks even when there is no cockerel shown. Weathercocks predominate, however, and can be seen in any shape, form or material. Sometimes in copper sheathed, often gilded, occasionally in lead. The bird’s head always faces into the wind with the tail behind, naturally the larger part, sometimes looking ridiculous.

Vanes in the shape of ships probably follow cockerels in popularity, especially in coastal towns and ports, where fishing trawlers skippers depend so much on the weather that in turn was the will of the wind.

Farms quite often have vanes for the same practical reason, as do the fishing ports. A wind change could mean a change of weather for the good and time to plough or sow.

Rural vanes are often in the shape of a country theme, such as horses ploughing, ridden or pulling some form of transport. Shapes of farm animals and birds are also popular.

Weather, of course, is a major talking point. We keep a weather eye on things, we make heavy weather of other things, and we can be under the weather or weathering life’s storms.

The world’s largest weather vane is JEREZ, Spain. A challenger for the world’s largest weathervane is located alongside Whitehorse International Airport, Yukon. The weathervane is a retired Douglas DC-3 atop a swivelling support. The vane only requires a 5-km/hour wind to rotate.

The term weathervane is also a slang word for a politician who has frequent changes of opinion.

Long Range forecast for the Sunshine Coast

On 3^rd of August 2009, on TV Channel 7 Ken Ring, long range New Zealand forecaster said the Sunshine Coast would have a very wet 3^rd week of December and we would have a very high temperature over Christmas.  The second half of January 2010 would also be very wet. On 3^rd April 2010 there will be a tropical cyclone, or remains of one, off Fraser Island. This will be the fourth cyclone of the TC season.

Harry and Humidity:

Some people are still unclear on the concept of relative humidity. You seem to get it confused with another relative, Uncle Harry. Uncle Harry, who gets flustered easily and tends to perspire even when the air conditioner is set at 10ºC, does remind us of relative humidity, so we understand your confusion.

Just as Uncle Harry’s copious perspiration and cries of “Wow- it’s hot as Hades in here!” do not indicate the actual temperature in the room, relative humidity does not indicate the actual amount of water vapour in the air.

Instead, RH tells us how close the air is to being saturated. RH, which is what our weather station reports, is expressed as a percentage that indicates the amount of water vapour actually in the air compared to the amount of water vapour required for saturation at that particular pressure and temperature. Absolute humidity, on the other hand, is a measure of the actual water vapour density in a fixed volume of air – dew point is an indication of this.

Uncle Harry, on a warm, muggy day is often heard to sigh, as he sits in the shade of his oak tree and mops his brow with a soggy handkerchief, “I don’t mind the heat. I just can’t take this awful humidity.”

He is explaining the difference, in human terms, between relative and absolute humidity. When we are warm, we perspire. The moisture evaporates into the air and cools the skin. If the RH is low, this evaporation happens very quickly and we perceive a lower air temperature. But when the RH is high and the air is approaching saturation, evaporation slows or halts and we sense higher air temperatures. Uncle Harry is right. With his very effective perspiration system, he would be more comfortable sitting in the shade of a cactus on an even warmer day in the desert!

Relative humidity changes during the course of a day, but not because the amount of water vapours in the air changes much. It is the changing of air temperature that changes RH. As the air cools, RH increases. As it warms, RH decreases.

So when Uncle Harry waddles over to your thermostat and thumbs it far to the left, he effectively lowers the RH! When the air conditioner cools the air, it increases its RH up to the point of saturation. The water vapour then condenses into liquid and drains out of the system. The cooled and dried air is then pumped into the house. In the winter, your heating system also dehumidifies the air. The cold air outside has little water vapour. When this air is pulled into the house and heated, the vapour capacity of the air rises dramatically, and so the RH plummets. You end up with desert-dry conditions inside the house. Any perspiration evaporates very quickly, leading to the famous winter dry skin, scratchy throat, and dry mucus membranes.

So remember, while Uncle Harry is a humid relative, he’s not, we repeat, NOT, relative humidity.

 anon

• What falls as it rises and rises as it falls?
• The answer is, of course, the barometer because pressure decreases as altitude increases and so the barometer will fall as you climb a mountain or go up in a balloon!
• With a series of high pressure systems sweeping across the continent, as is usual during the winter months, one’s thoughts turn to the aneroid barometer found in many homes on the Range where the day often begins by the ritual tapping of the barometer to see which way the needle jumps!
• Although barometers should be adjusted for height above sea level by turning a small screw at the back, it does make sense to adjust for Mean Sea level instead so that it is easier to read weather maps on TV or newspapers.
• Always bear in mind it is more important to know what the barometer is doing rather than what the needle is showing.
• Early home barometers were very helpful by including a little blue and red disc to show whether the barometric pressure was rising or falling. This avoided the need for ritual ‘tapping’!
• If your barometer is a more recent model the face will show the units in hectopascals, the unit of pressure measurement accepted around the world. However, should the markings be in inches then multiplying by 33.85 will bring inches to hectopascals (hPa).
• The face may also show such words as Stormy, Rain, Change, Fair, Very Dry as a guide to current or future weather, but in fact has little practical application other than being decorative.
• Atmospheric pressure changes are irregular and knowledge of them is very important in the study of winds and weather patterns in forecasting weather.
• Barometers used to predict weather should be read in conjunction with outside air temperature and relative humidity. The following guide lines are used by some weather watchers.
• Barometer steady, humidity increase, temperature falls = Chance of rain
• Barometer steady, humidity decreases, temperature rises = Fine
• Barometer rises, humidity increases, temperature steady = Showers.
• Barometer quick rise/fall, humidity increases, temperature plunges = Thunderstorms.
• Barometer falling, high humidity, temperature rising = Heavy rain.
• Barometer rising, humidity falls, temperature rising = Wind change, fine.
• Barometer falling, humidity high, temperature plunging = Weather deteriorating rapidly.
• Finally, watch the Weather Bureau’s synoptic maps and compare your location’s barometric pressure with the isobars shown.