A Few Facts on Meteorology

In agrarian times, our ancestors forecast the weather according to changes in sunlight and rain, wind direction, light and shade, cloud formations, and temperature, as a guide for planting and harvesting crops. Today most people are less sensitive to changes in the weather, as they can simply tune into weather reports whose accuracy is assured by weather stations distributed across the country. Data and information are collected from all these stations and after they are analyzed a forecast is made.

At present, Taiwan has a total of 26 official weather stations, 22 of which are located at elevations of less than 1,000 meters above sea level. Of the remaining four, the Sun Moon Lake and Mt. Tatun stations are at around 1,000 m, the Mt. Ali station at 2,413 m, and the Yushan station at 3,858 m. The data collected by low-elevation weather stations lacks detailed information on high altitude cloud cover and air current changes, among other things. Although it is now possible to use satellite technology, high-altitude weather balloons and other advanced technology to measure the temperature, air pressure and humidity at high altitudes, the collection of data on such things as visibility, cloud type and cloud height depends on visual observation and cannot be achieved by automated instruments. As such, the maintenance of high-altitude weather stations remains imperative for accurate data.

Apart from its high altitude, the Yushan Weather Station is also located on the Tropic of Cancer. This is a special location combining high altitude with low longitude, precisely where the Pacific and continental air masses interact. That means meteorological data observed here has an important reference value for local weather forecasts.

However, the weather also needs to be better understood as a key element in warfare. In Romance of the Three Kingdoms, Zhuge Liang is particularly proficient at observing changes in the weather, using an "easterly wind" to seize 100,000 arrows from Cao Cao. In the Yuan dynasty, Kublai Kahn led the Mongol forces in an attack on Japan, only to encounter a typhoon whilst at sea. In the 18th century, the French Emperor Napoleon attacked Tsarist Russia, only to find his forces assailed by rainstorms and hailstones. During the 1991 invasion of Iraq, the Iraqi authorities banned the publication of any weather data, forcing the US to rely on its satellites and cloud charts in making educated guesses about changes in the weather over the country and adjusting accordingly the direction of missiles and battlefield strategy. Weather factors are always extremely important in the decision to launch a US space shuttle.

In fact, it was military reasoning that led the Japanese to establish a weather station on the north peak of Yushan: "In 1943, World War II was nearly over," says Hsieh Hsin-tien. "The Japanese started the Pacific War and it was to protect their military airfields in the Chiayi-Tainan area of Taiwan by providing accurate meteorological information for safe take-offs and landings, that a decision was taken to expend whatever it took in manpower and resources to build the Yushan Weather Station." In other words, important practical considerations have encouraged people to apply more scientific methods in their observation of the weather, laying the foundation for major advances in the modern study of meteorology.

Note: In October 2003, the Executive Yuan's Research, Development and Evaluation Commission set up real-time video feed equipment on the north peak of Yushan. Access www.gov.tw, then select English > Webcam > Nantou County > Yushan, to see a view from the highest mountain in Taiwan.