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.
The CIA has a message for Chinese government officials worried about their place in Chinese President Xi Jinping’s (習近平) government: Come work with us. The agency released two Mandarin-language videos on social media on Thursday inviting disgruntled officials to contact the CIA. The recruitment videos posted on YouTube and X racked up more than 5 million views combined in their first day. The outreach comes as CIA Director John Ratcliffe has vowed to boost the agency’s use of intelligence from human sources and its focus on China, which has recently targeted US officials with its own espionage operations. The videos are “aimed at
STEADFAST FRIEND: The bills encourage increased Taiwan-US engagement and address China’s distortion of UN Resolution 2758 to isolate Taiwan internationally The Presidential Office yesterday thanked the US House of Representatives for unanimously passing two Taiwan-related bills highlighting its solid support for Taiwan’s democracy and global participation, and for deepening bilateral relations. One of the bills, the Taiwan Assurance Implementation Act, requires the US Department of State to periodically review its guidelines for engagement with Taiwan, and report to the US Congress on the guidelines and plans to lift self-imposed limitations on US-Taiwan engagement. The other bill is the Taiwan International Solidarity Act, which clarifies that UN Resolution 2758 does not address the issue of the representation of Taiwan or its people in
US Indo-Pacific Commander Admiral Samuel Paparo on Friday expressed concern over the rate at which China is diversifying its military exercises, the Financial Times (FT) reported on Saturday. “The rates of change on the depth and breadth of their exercises is the one non-linear effect that I’ve seen in the last year that wakes me up at night or keeps me up at night,” Paparo was quoted by FT as saying while attending the annual Sedona Forum at the McCain Institute in Arizona. Paparo also expressed concern over the speed with which China was expanding its military. While the US
SHIFT: Taiwan’s better-than-expected first-quarter GDP and signs of weakness in the US have driven global capital back to emerging markets, the central bank head said The central bank yesterday blamed market speculation for the steep rise in the local currency, and urged exporters and financial institutions to stay calm and stop panic sell-offs to avoid hurting their own profitability. The nation’s top monetary policymaker said that it would step in, if necessary, to maintain order and stability in the foreign exchange market. The remarks came as the NT dollar yesterday closed up NT$0.919 to NT$30.145 against the US dollar in Taipei trading, after rising as high as NT$29.59 in intraday trading. The local currency has surged 5.85 percent against the greenback over the past two sessions, central