21 February 2008 at 7:43 am #7120
During the recent cold spell, I sometimes looked at real time temperatures for Ngong Ping (Lantau) on HK Observatory website: rather fascinated by how low temps were there, sometimes around 3C even daytime, whilce Cheung Chau – where I am – down to maybe 8C.
Noticed that sometimes, temp there suddenly rose, maybe higher than at sea level stations for short time (10C or higher?) – maybe an hour or so, then fell just as suddenly to around same level it had been before.
Thought maybe a faulty instrument; but also, I read that China snows caused by moist warm air moving north over cold air – wondered if this warmer air was sometimes touching down at Ngong Ping.
I emailed HK Observatory to ask about this; and just received this reply:Quote:References are made to your email dated 31 January 2008 and my subsequent email of 12 February 2008.
We have examined our record in late January and the meteorological instrument measuring temperatures at Ngong Ping was normal.
Under the dominance of the winter monsoon in late January, warmer air originated from the ocean can head to temperature rise in high altitude, like Ngong Ping while temperature remaining quite steady in other stations. A schematic diagram is at http://www.hko.gov.hk/wxinfo/news/2008/pre0128e.htm for reference.
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