• Sun
  • Dec 21, 2014
  • Updated: 3:01am
NewsHong Kong

Hong Kong will see more extreme temperatures in future, say scientists

Blame our fluctuating temperatures on winter monsoon, scientists say

PUBLISHED : Thursday, 20 February, 2014, 3:17am
UPDATED : Thursday, 20 February, 2014, 8:59am

Hongkongers may see more extreme weather and cold winter spells in the future as the world's oceans warm up, scientists say.

The warning was issued as temperatures dropped dramatically from a warm and humid 21.5 degrees Celsius on Tuesday afternoon to a low of 7.9 yesterday morning.

Just a week ago Hong Kong was even colder than Sochi, Russia - where the Winter Olympics are being held - before temperatures rose rapidly to the low 20s.

The cold fronts hitting the city have been a result of a winter monsoon over southern China, caused by differential warming and cooling over land and sea.

This type of rapid fluctuation in temperature is quite common in the late winter and early spring, said Johnny Chan Chung-leun, dean of City University's school of energy and environment.

"During this period, the north-to-south temperature differences are smaller as the sun begins to warm the tropical parts of the northern hemisphere," said Chan, chair professor of atmospheric science.

Sandy Song Man-kuen, senior scientific officer at the Observatory, explained the phenomenon in terms of the change of a mild air mass to a cold one.

"Steep drops of more than 10 degrees have occurred on several occasions in the past. It is not the first time," she said.

The extent of the hot-cold fluctuations also depends on wave motions. As west-to-east wave amplitudes rose, some areas would get abnormally colder and others warmer, Chan said.

"Wave amplitudes are determined by the difference in temperatures between the northern and tropical parts of the northern hemisphere, which may also be affected by ocean temperatures," the professor said.

He noted that extreme differences in temperatures between the north and tropics were one of the causes of instability in the climate.

"With climate change, Hong Kong could see more cold snaps, extreme heat in the summer and much higher rainfall as warmer oceans release more atmospheric vapour," he warned.

The city has seen temperatures falling into the single digits for the second week this month, making this February the coldest in 18 years.

There was a bright spot in the gloom, however. Hong Kong's unusually chilly waters welcomed a group of visitors - a pod of about 100 false killer whales sighted over two days last week, although no firm link with the weather could be established.

The weatherman says cold weather will continue until the weekend, when the monsoon moderates gradually.

Observatory data shows that there is about one very cold day - where the temperature falls below 7 degrees - every two years.

The longest recorded cold snaps lasted six days, in the years 1893, 1951, 1955 and 1966.


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This article is now closed to comments

Oh really? A few weeks ago the HKO was saying that Winter temperatures would slowly rise in the future. Basically, these weather experts have no idea what's going to happen to our weather.
It's Winter so it will be cold - get over yourselves!
This is such an appallingly inaccurate and misleading article, Ernest Kao should be ashamed to have written it and the SCMP to have published it. As for the explanations given by the so-called scientists, one despairs at their triviality although a close analysis of what they say does not support any other conclusion than that the weather is behaving perfectly normally within the bounds of natural variation.
The climate changes, it always has, it always will and there is nothing than man can do to alter that.
there is no central heating in housing here and insulation is awful.
Add to that this retarded idea of airconditioning in winters (including in trains, buses and cabs), which is not only likely to make you sick but also consumes adds to environmental woes.
Why is the system so smart?
dienw, is quite correct. The HKO stated that in the future days where we see low temperatures, I think they said something like 12c or below, would become rarer and rarer. Of course, the movie 'The Day After...' highlights the point of warming oceans leading to colder weather in some areas.
I think the HKO simply has problems communicating.
"The longest recorded cold snaps lasted six days, in the years 1893, 1951, 1955 and 1966"...???
You can search SCMP - "Longest cold snap in 40 years to keep city shivering into next week" in 2008 and that snap lasted 20 days.
It is pretty depressing when journalists are too lazy to even do a cursory search of their own paper to ensure accuracy.
I think you missunderstand the article. I don't blame that on you! Especially the part about "wave amplitudes" difficult to understand without more background.
The main message is that with climate change, temperature changes stronger between cold and warm during a winter. You have more extreme cold days, but also more extreme hot days. If you calculate the mean temperature over the whole winter, the temperatures could still rise slowly. There is no contradiction.
Thanks, bmr. That is what I was referring to. gkuhl obviously didn't see that article.
I don't see there's a need for central heating in housing in Hong Kong generally. If I have to choose, I need air-conditioning than heating in Hong Kong. This is because at least air-conditioning can keep you dry.
Scientists are so full of themselves sometimes.

Of course, a scientist would say that HK will see extreme weather in the future. That’s the only way to get published in the media.
If a scientist just said that HK will experience normal weather, there’s no story!
If we do experience extreme weather, the scientist can boast about how he was right. If we don’t experience extreme weather, nobody will remember the scientist. It’s a win-win situation.


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