Taipei-The mercury dropped to the lowest this autumn in areas north of Hsinchu County early Monday, with 14.7 degrees Celsius recorded in Tamsui, New Taipei, according to the Central Weather Bureau (CWB).
The drop in temperature was caused by the effect of radiative cooling in the Earth's atmospheric system, a process by which long-wave (infrared) radiation is emitted to balance the absorption of short-wave (visible light) energy from the sun, the bureau said.
Lows of 15-18 degrees were recorded in areas north of Taichung in central Taiwan, Yilan and Hualien Counties in the east, and 19-21 degrees in the rest of the country, CWB data showed.
Daytime temperatures will rise to 26-28 degrees on Monday in northern and northeastern Taiwan and 29 degrees in the south, due to weakening northeasterly winds, thin cloud cover and radiative heat from the sun, the weather bureau forecast.
The CWB advised people to be prepared for a big day-night temperature differential, which could be more than 10 degrees.
Meanwhile, northeasterly winds will bring pollutant particles to Taiwan, the Environmental Protection Administration (EPA) said, noting that the particles will accumulate more on the leeward side of areas south of Taichung because of poor dispersal conditions.
The Air Quality Index (AQI) flashed an "orange alert" in Yunlin, Chiayi and Tainan, as well as the outlying county of Kinmen Monday morning, indicating unhealthy air quality for sensitive groups.
The EPA said the air quality was fair in most places in western Taiwan and good in Hualien and Taitung in the east.
Source: Focus Taiwan News Channel