■天文台指出本年多達12項天氣數據打破紀錄，其中7項與溫度有關。 資料圖片下文摘錄自香港《文匯報》12月1日報道：
【原文】香港天文台（Hong Kong Observatory）指出，以往本港平均每10年才會出現6天的嚴寒天氣，今年初已出現3天，本年至今更有多達12項數據打破自1884年以來的紀錄，大多在溫度方面創新高。
天文台早前公佈截至11月29日的本港氣候統計及極端天氣（extreme weather）摘要（abstract），多達12項數據破紀錄，其中7項在溫度上創新高，如全年酷熱天氣日數達38天，10月平均最高氣溫達29.1度等；今年夏季6月至8月的平均氣溫（mean temperature）也達29.2度，排名歷來最熱第三位。
此外，有4項紀錄與高雨量（rainfall）有關，餘下一項則涉及氣壓（air pressure）創新高。
7項溫度新高 與全球暖化有關
截至當天，共有9個熱帶氣旋（tropical cyclone）進入本港500公里範圍，是1999年以來的最高紀錄。有9個熱帶氣旋令天文台需發出熱帶氣旋警告信號（warning signal），更是1993年以來的最高紀錄。颱風「海馬」於10月21日令本港發出八號風球（typhoon signal No.8），是21年來再次在10月出現八號風球。
天文台台長岑智明指出，今年多項涉及溫度的數據創新高，與全球天氣暖化（global warming）有很大關係，北極（Arctic）的氣溫於10月時已比正常高，上月更甚，比正常高出8度至10度，因此未來香港以至全球，或會有更多高溫的日子產生。
嚴寒日子料亦會出現
不過，高溫日子多，不等於不會出現嚴寒天氣。按以往記錄，本港平均每10年才會出現6天只有7度以下的嚴寒天氣，可是今年初本港卻已出現3天，溫度低至3.1度，更出現結冰（freezing）現象。
岑智明解釋，近年有研究指，北極海冰減少，令北極變暖加劇，並使北半球（Northern Hemisphere）高空西風急流（westerly jet stream）減慢，有利急流出現較大起伏波動，急流可能移動緩慢，甚至停滯（stagnant）不前，波動的一側可能有異常溫暖氣團由南向北輸送，另一側卻是北方冷空氣南下。
因此寒潮（cold wave）會否影響本港，視乎冷空氣的南下路徑，當中亦有隨機性的不確定因素。
天文台預料今冬本港氣溫接近正常，平均介乎16.6度至17.4度，但指出日夜之間的天氣和氣溫變化依然可以很大，故間中會出現12度或以下寒冷天氣，甚至7度或以下嚴寒天氣。
Extreme weather breaks 12 records
【譯文】Freezing cold weather that happens six days every 10 years had already occurred three days at the beginning of 2016. Within the year the SAR has broken 12 of its weather records since 1884, most of them related to high temperatures, the Hong Kong Observatory said.
The Observatory has recently released the climate and extreme weather statistical abstract. As of November 29, 12 numbers hit a record high. Seven were temperature-related.
To cite some, the city had registered 38 very hot days; the maximum mean temperature in October reached 29.1℃; the mean temperature from June to August hit 29.2℃, bringing in the third hottest summer ever. Four records were about heavy rainfall. The remaining one was on the highest air pressure ever measured.
7 temperature records related to global warming
Nine tropical cyclones came within 500 kilometers of Hong Kong, which was the most frequent since 1999, effecting the highest number of storm warning signals issued since 1993.
The Observatory had also hoisted the typhoon signal No.8 on October 21 because of the typhoon "Seahorse". The last time when such signal was hoisted in October dates from 21 years ago.
Observatory director Shun Chi-ming pointed out that a number of temperature data went up record high because of the impacts of global warming. The temperature in the Arctic in October was higher than normal, and the situation even went worse last month, which indicated 8℃ to 10℃ rises. Therefore it is likely the number of "very hot" days go up in Hong Kong and around the globe.
Freezing cold days also expected
However, it does not mean that very cold weather will no longer exist while "very hot" days continue to increase. According to previous records, an average of six cold days with a temperature below 7℃ would be recorded in every 10 years, but three cold days-at the lowest temperature of 3.1℃ and near freezing-had already been observed at the beginning of this year.
Shun cited recent studies which indicate that reduction of the Arctic sea ice coverage has heated up the area's climate and slowed down the westerly jet stream above the Northern Hemisphere, leading to large fluctuations in the jet stream.
The stream might move slowly or become stagnant, causing warm air to shift from south to north or northern cold air to flow southward. Whether Hong Kong would be affected by a cold wave depends on the journey of the cold air mass, and it would involve many unpredictable factors.
The Observatory predicted that the winter of this year will see normal levels, with temperatures ranging from 16.6℃ to 17.4℃, but noted there can be huge day-night fluctuations and freezing cold weather below 12℃ or even as low as 7℃may occur occasionally.■龐嘉儀
Questions
1. 全球的溫度和降雨變化容易受哪種異常的氣候現象影響？
2. 極端天氣除了熱浪、寒潮外，還有哪些？
3. 香港暖化主要是由於全球暖化和哪個主要因素所影響？
4. 承上題，這個因素對香港暖化的貢獻佔比可高達幾多？
5. 受氣候影響，維多利亞港自1954年至今有何變化？
Answer
1. 厄爾尼諾現象（El Nino）
2. 洪水、旱災、颶風、龍捲風等
3. 本地城市化（urbanization）
4. 50%
5. 平均海平面（mean sea level）上升