Talk of the town in Nanjing of late has been the upcoming winter, with much of the populace convincing themselves (and others) that the cold spell of 2020/21 is going to be a shocker. Scientific data, on the other hand, reveals a somewhat different picture.
This past October was certainly unseasonably cold. More often than not a month with almost perfect conditions that would have us all sat outside, this year’s tenth month was characterised by chills and a variable climate, to say the least. The knock-on effect was to kick the rumour mongering machine up a gear.
Not long before that, the magnificent, pollution-free summer we have enjoyed this year got the predictions started. Many a Nanjinger believes in a fairly simple weather forecasting logic; the hotter the summer, the colder the winter.
The reality of climate prediction is a little more complex. Key to it this year is La Niña, the cold sea surface temperature pattern that forms in the Pacific Ocean, whereby strong winds blow warm water at the ocean’s surface from South America to Indonesia.
According to the World Meteorological Organisation, most forecasts indicate that “the 2020/2021 La Niña is likely to be a moderate to strong event”. This equates to a warmer than average winter for Nanjing.
This prediction is backed up locally too. Located in the K-Pouch incubator in Nanjing’s Jiangbei New Area, the Institute for Climate and Application Research (ICAR) carries out advanced research into climate dynamics, climate model development, climate prediction and projection, climate application and disaster warning.
Available on the Institute’s website is a publicly accessible data portal offering a broad range of climate forecasts, in a surprising degree of detail, while tailor-made analysis is offered to paying customers.
From the “Surface Air Temp Anomaly” section of the portal, we learn it is predicted that “most parts of the world will experience a warmer-than-normal condition in the winter of 2020, except for parts of northern North America, northern South America and Australia”.
As for that all important rainfall which often makes Nanjing winters feel colder than they actually are, the portal tells us, “the eastern part of East China will experience a remarkably reduced precipitation condition”.
As to accuracy of such forecasts, The Nanjinger spoke with Luo Jingjia, professor and director at the Institute, which is also affiliated with the School of Atmospheric Sciences at Nanjing University of Information Science and Technology (NUIST).
“The figures show the anomaly correlation skill of our model in predicting surface air temperature and precipitation in winter (Dec-Feb) and spring (Mar-May). Positive anomaly correlation skills in Jiangsu Province indicate that our forecasts are higher than climatological forecasts”, Luo said.
So with foreigners remaining in Nanjing on account of COVID in with little chance of a white Christmas this year, the outlook for 2021 is altogether different. According to the Institute’s portal, “In the autumn of 2021 (from Sep 2021 to Nov 2021), there will be a colder-than-normal condition in East Asia, except for southwest China and its surrounding areas. Besides, Central and East China will experience a wetter autumn”.
