Chapter 4 : Weather

Weather and Life

        “Before going to school, I looked out to see what it was like outside. So glad to find the weather was fine. Then I grabbed my bag and went to school.... Finally—I’d been waiting forever!—we had phys-ed. The sun was scorching. We were all bathed in sweat playing basketball.... By the second class in the afternoon, it was hot and windless. It made me feel really sleepy. Before long, the sky grew dark and cloudy. All of a sudden, the rain poured down. There were thunderclaps! My drowsiness disappeared instantly and I started listening to the teacher again.... I didn’t bring umbrella today, but I wasn’t worried at all, cause I knew that it would soon clear up.... The sky did clear up at the end of the day, just as I’d expected. I walked home in the setting sun.... After finishing my homework, I went out to take a walk. Looking at the crescent moon, I suddenly felt a bit chilly and decided to go back and put on another layer.... What fickle weather today!”

       

This is a diary entry of a junior high school student. I bet you have had similar experiences. Before you go to school everyday, you check your bag to see if you have everything. You also decide whether to bring an umbrella or an extra shirt. These considerations are all directly related to the “weather.” But what is weather? Weather is the short term state of the atmosphere. It is constantly changing. We always notice the temperature and rain, but what else is there to the weather?

 

Weather Factors

        Television, radio, or newspaper weather reports tell us about changes in weather in terms of four factors. Take, for example, the sea to the north of Taiwan:

1.      Air temperature: given in Celsius.

2.      Rainfall: The amount of rain that falls in a certain period, usually measured in millimeters (mm).

3.      Barometric Pressure: The pressure created by the atmosphere, measured in hPa (100 Pa). Normally, we are not conscious of barometric pressure, but it has a huge influence on the weather. Wind is created when air flows from a high pressure area to a low pressure area.

4.      Wind: The horizontal flow of air. Weather reports commonly state the direction and velocity of the wind.

 

        To understand changes in each factor, we need to make observations at the same time every day and record the results. This is called “meteorological observation.” These weather observations can be conducted in many ways. The most basic way is to observe the weather at ground level.

 

Weather Forecasts

There is a saying “there are storms we cannot weather,” but with improvements in technology and better international cooporation, storms have become more and more predictable. Weather forecasts have become an important part of our daily lives. But where does the information for the weather reports come from?

The professional weather experts of the Center Weather Bureau receive satellite images of the earth. At the same time, they gather information from several hundred weather stations and input them into mainframe computers, to create ground and high altitude weather maps. Then they analyze the changing weather patterns. Finally, a weather report is issued by the Central Weather Bureau. We can get weather information through the TV, radio, newspaper, telephone, and the CWB website (http://www.cwb.gov.tw).