New research suggests that air pollution indirectly reduces the amount of rainfall in northern Taiwan during autumn, which might have exacerbated the water shortage at New Taipei City’s Shihmen Reservoir (石門水庫).
Researchers from National Central University (NCU) and the State University of New York at Albany analyzed 13 years of satellite and surface data for the study, which was published on March 23 in the journal Atmospheric Chemistry and Physics.
Taiwan receives most of its annual rainfall from May to September during the plum rain and typhoon seasons, NCU Department of Atmospheric Sciences associate professor Wang Sheng-hsiang (王聖翔) said.
Photo courtesy of National Central University
Although there is relatively less rainfall during fall and winter, it is key to maintaining reservoir levels, Wang said.
However, it is also when pollution tends to be most severe, which not only affects health, but can also affect the characteristics of rain droplets, he added.
Researchers analyzed data from 2005 to 2017 on concentrations of PM2.5 — airborne particulate matter smaller than 2.5 micrometers — meteorological parameters, such as wind direction and temperature, raindrop size, aerosols and cloud properties, to determine the effect that aerosols might have on clouds and drizzle during autumn over northern Taiwan.
They found that in the densely industrialized northwest, the season is mainly dominated by warm, thin and broken clouds, which are defined as having an internal temperature of at least 0°C.
Aerosols were discovered to have an indirect effect on the clouds, meaning that as aerosol concentrations rose, cloud droplets became smaller and more numerous, with drizzles occurring less frequently.
The data also reflected this, as “polluted” days saw about 6.8mm less daily average rainfall than “clean” days, with polluted days defined as the 80th percentile of daily average PM2.5, while clean days fell in the 20th percentile.
Lead author of the study, Chen Ying-chieh (陳映潔), obtained a graduate degree from NCU’s Department of Atmospheric Sciences.
As a graduate student, she was in the first cohort of the US-Taiwan Partnership for International Research and Education (PIRE), which sent her on a two-month exchange to the US.
PIRE is run by the Ministry of Science and Technology and the US National Science Foundation through NCU and the State University of New York at Albany. The program aims to promote research collaboration on weather and climate prediction, and emergency response strategies.
A TAIWAN FIRST: The duo are the first badminton players from Taiwan to climb an Olympic podium, and Tai Tzu-ying has a shot at doing the same today Taiwanese badminton duo Lee Yang (李洋) and Wang Chi-lin (王齊麟) yesterday won the nation’s first Olympic gold medal in the sport when they prevailed over a third-seeded Chinese pair in the final of the men’s doubles at the Tokyo Olympics. Lee and Wang, both first-time Olympians, defeated Liu Yuchen (劉雨辰) and Li Junhui (李俊慧) 21-18, 21-12 in a 34-minute final at the Musashino Forest Sports Plaza. As of yesterday, Taiwan had bagged seven medals in Tokyo — two golds, two silvers and three bronzes — topping its previous best of five medals in 2000 and 2004. Taiwan moved to No. 17 in the
‘TEAM TAIWAN’: Taiwanese athletes have performed admirably and raised the nation’s profile, but many abroad still think they are Chinese, an advocate said Advocacy groups have called for the national team to compete under the name “Taiwan” at the Tokyo Olympics, while former Olympian Chi Cheng (紀政) has launched another referendum petition on the issue. Taiwanese athletes have performed outstandingly at the Olympics and have raised the nation’s profile on the world stage, Northern Taiwan Society chairman Lee Chuan-hsin (李川信) said on Friday. “Many foreign news agencies, including Japan’s NHK, have called our delegation ‘Taiwan’ instead of ‘Chinese Taipei.’ Therefore our own people and politicians should also speak of ‘Team Taiwan’ and Taiwanese athletes,” he said. “However, in Taiwan, most of the time the Taiwanese team
SOAKED: Although rain in central and southern Taiwan is to ease today, chances of heavy or extremely heavy rain would be high in the morning, a CWB forecaster said Extreme torrential rain brought by a southwesterly jet stream yesterday wreaked havoc in central and southern Taiwan, causing flash floods and triggering mudflows and landslides in mountainous areas. By 5pm yesterday, the Central Weather Bureau’s observation station in Yuyoushan (御油山) in Kaohsiung’s Liouguei District (六龜) had registered accumulated rainfall of 726.5mm since 12am on Saturday, the highest among the bureau’s observation stations. It was followed by the observation station in Kaohsiung’s Maolin District (茂林), which recorded accumulated rainfall of 671.5mm over the period. Six of the 10 observation stations that recorded the highest accumulated rainfall yesterday were in Liouguei, bureau
MEDIGEN: The Central Epidemic Command Center plans to wait until about 500,000 to 600,000 doses have passed testing before offering it in the vaccination program The inspection of the first four batches of the domestic COVID-19 vaccine has been completed and the doses are ready to be rolled out, the Food and Drug Administration (FDA) said yesterday. The inspection of the four batches of the vaccine made by Medigen Vaccine Biologics Corp (高端疫苗), a total of 265,528 doses, was completed on Friday last week and they are being sealed at a designated warehouse in preparation for use, FDA Research and Inspection Division head Wang Teh-yuan (王德原) said. The sealing was expected to be completed yesterday evening, he said. The Medigen vaccine, the first protein-based COVID-19 vaccine to be