There’s still about a month to go until winter officially ends, but the number of days on which weather stations in Taipei have shown temperatures falling below 10oC has already reached 13, with six days recorded last month and seven days in December.
According to the Central Weather Bureau (CWB), over the past 30 years Taipei had an average of 3.3 days of low temperatures in January — defined as less than 10oC.
The average temperature in Taipei last month was 13.8oC, 2.35oC lower than the 30-year temperature average of 16.15oC, marking the lowest average monthly temperature in 40 years and the ninth-lowest recorded in the past 100 years, it said.
Photo: Hua Meng-ching, TAIPEI TIMES
“It was not only in Taipei that was cold this winter, but nationwide,” said Chia Hsin-hsing (賈新興), chief of the bureau’s long range forecast section.
Chia said that among the 25 weather stations nationwide, 21 recorded low temperatures that were among the tenth-lowest since the stations were established — the four stations in Taichung, Yushan (玉山), Hualien County and Alishan (阿里山) were exceptions.
Bureau statistics reinforced the widely held perception that this winter has been colder than average, but scientists have not yet come to a conclusion as to the cause, analysts said.
Weather Forecast Center director Cheng Ming-dean (鄭明典) attributed the low temperatures to the impact of La Nina, an abnormal cooling of the equatorial Pacific Ocean, coupled with a negative phase of Arctic Oscillation (AO), which allows frigid polar air to slide south, displacing warmer air to the north.
The AO is a natural weather pattern of differences in air pressure between the Arctic and mid-latitudes. When the AO is in a negative mode, the pressure gradient weakens, with air pressure higher than average in the Arctic and lower than average in the mid-latitudes.
“Both events bring cold to certain areas. This year the temperatures of the affected areas got cooler as La Nina coincided with the negative Arctic Oscillation,” Cheng said.
Located in one of the three paths along which arctic air masses flow southward from Siberia toward Inner Mongolia into northeastern China, Japan and the Korean Peninsula, Taiwan also receives cold arctic air when it plunges into the region, Cheng said.
Countries lying along the route when cold air from the Arctic spreads out southward into Western European countries such as Norway, Germany and the UK, also saw damage caused by unusually extensive snow, while the weather pattern allowed arctic air from northwestern Canada to flow straight into the eastern portion of the US.
It may seem contradictory that the rise in world temperature leads to extra cold winters, but Cheng said that global warming is one the reasons behind the increase in frequency of cold arctic masses moving southward, despite the link being unattested.
It’s “theoretically possible” because increased ice melting, as a result of global warming, can heat up the upper layers of the atmosphere, which will then lead to changes in wind patterns over the Arctic, causing Arctic cold air masses to move outward, Cheng said.
Peng Chi-ming (彭啟明), chief executive of the Weather Risk Management Co, said scientists did not yet know how global warming affects AO because it was not until as recently as 10 to 20 years ago that scientists gained more knowledge about the weather pattern.
“Just because there has been an increase in frequency at which Arctic Oscillation is in a negative mode in recent years does not mean that it is a result of rising [global] temperatures, despite the fact that the scientific evidence for the existence of global warming continues to mount,” he said.
Liu Koung-ying (劉廣英), dean of the atmospheric sciences department at the Chinese Culture University, said “this winter has not been cold if the average temperature is put in the context of a long enough cycle, say 30 years,” instead of three years or 10 years.
According to the CWB, the average temperature in December and last month in Taipei was 15.6oC, slightly lower than an average of 16.85oC between 1981 and last year and an average of 15.9oC between 1951 and 1980.
Further cases of record--shattering winters include 1975 when it rained all February, 1983 when there was a consecutive 65 days of snow on Yushan and 1963 when the average daily temperature was below 10oC for 28 days in January, he said.
“I do not see this winter as unusually cold, compared with the winters I have been through in my life. I would say that this is a normal winter. Warmness in winter is abnormal,” Liu said.
In recent years the Earth has been rich with weather abnormalities caused partly by the east-to-west trade winds characteristic of La Nina, mostly likely linked to the continued increase in carbon dioxide and partly by a north-south seesaw weather pattern in the North Atlantic, known as North Atlantic Oscillation (NOA), which is closely related to AO, Liu said.
During negative phases of the NOA, big zones of high pressure spreading down from Greenland stick around for weeks, dragging bitterly cold winds out of the Arctic, said Liu, adding that it occurs periodically and naturally when Arctic air masses accumulate to a certain level over a period of time.
‘DENIAL DEFENSE’: The US would increase its military presence with uncrewed ships, and submarines, while boosting defense in the Indo-Pacific, a Pete Hegseth memo said The US is reorienting its military strategy to focus primarily on deterring a potential Chinese invasion of Taiwan, a memo signed by US Secretary of Defense Pete Hegseth showed. The memo also called on Taiwan to increase its defense spending. The document, known as the “Interim National Defense Strategic Guidance,” was distributed this month and detailed the national defense plans of US President Donald Trump’s administration, an article in the Washington Post said on Saturday. It outlines how the US can prepare for a potential war with China and defend itself from threats in the “near abroad,” including Greenland and the Panama
A wild live dugong was found in Taiwan for the first time in 88 years, after it was accidentally caught by a fisher’s net on Tuesday in Yilan County’s Fenniaolin (粉鳥林). This is the first sighting of the species in Taiwan since 1937, having already been considered “extinct” in the country and considered as “vulnerable” by the International Union for Conservation of Nature. A fisher surnamed Chen (陳) went to Fenniaolin to collect the fish in his netting, but instead caught a 3m long, 500kg dugong. The fisher released the animal back into the wild, not realizing it was an endangered species at
The High Prosecutors’ Office yesterday withdrew an appeal against the acquittal of a former bank manager 22 years after his death, marking Taiwan’s first instance of prosecutors rendering posthumous justice to a wrongfully convicted defendant. Chu Ching-en (諸慶恩) — formerly a manager at the Taipei branch of BNP Paribas — was in 1999 accused by Weng Mao-chung (翁茂鍾), then-president of Chia Her Industrial Co, of forging a request for a fixed deposit of US$10 million by I-Hwa Industrial Co, a subsidiary of Chia Her, which was used as collateral. Chu was ruled not guilty in the first trial, but was found guilty
DEADLOCK: As the commission is unable to forum a quorum to review license renewal applications, the channel operators are not at fault and can air past their license date The National Communications Commission (NCC) yesterday said that the Public Television Service (PTS) and 36 other television and radio broadcasters could continue airing, despite the commission’s inability to meet a quorum to review their license renewal applications. The licenses of PTS and the other channels are set to expire between this month and June. The National Communications Commission Organization Act (國家通訊傳播委員會組織法) stipulates that the commission must meet the mandated quorum of four to hold a valid meeting. The seven-member commission currently has only three commissioners. “We have informed the channel operators of the progress we have made in reviewing their license renewal applications, and