This morning, the frozen line finally withdrew from the Yangtze River Delta region. The lowest temperature in our province is 4~8 °C on the southeast coast, and -1~2 °C in most other areas.
The number of consecutive days with the lowest temperature below zero in Hefei and Nanjing stopped at 12 and 11 days, with Nanjing being the longest number of consecutive low temperature days below zero in December since 2005.
However, as the temperature warms up, another annoying problem arises, that is, haze!
Atmospheric visibility was greatly reduced, and the sky became gray.
This morning, fog and haze appeared in many places on the mainland, and meteorological monitoring showed that the visibility in some areas of Shanghai, northern Zhejiang, and western Sichuan Basin was less than 1 km.
There is heavy fog in most areas of Jiaxing, some dense fog, local strong dense fog, and the minimum visibility is only 22 meters in Pinghu Zhongdai.
The following picture is an observation map of weather phenomena in Zhejiang Province at 9 a.m. today, and this infinity symbol similar to "∞" on the map represents haze.
As you can see from this map, today's haze is almost all over the province of Zhejiang, even Zhoushan has not been spared, which shows that its impact is very wide.
Haze occurs due to the increase in particulate matter suspended in the atmosphere, and the failure of particulate matter to disperse due to calm weather.
(AQI distribution map at 10 o'clock today)
What are the characteristics of calm weather?
The first is the absence of rain, which prevents suspended particulate matter from being settled by rainwater;
There is also no strong wind when it is stable, which prevents the suspended particulate matter from diffusing horizontally;
At rest, there is often an inversion layer in the atmosphere, which prevents suspended particles from spreading vertically.
For example, in recent days, there has been no wind, no rain, and there is a temperature inversion in the atmosphere.
At 8 o'clock this morning, the temperature near the ground in Hangzhou was 3.4 °C, but the temperature at a height of about 1 kilometer vertically was above 8 °C, which shows that the inversion layer over Hangzhou is obvious.
Under normal circumstances, the air temperature near the surface is high and the air temperature is low, the atmosphere is "top-heavy", and the vertical air is easy to form convection, and the suspended particulate matter will be carried to the upper altitude to diffuse. But when an inversion is formed, convective activity weakens, and suspended particulate matter accumulates in the air near the surface, becoming the haze we see.
Haze and fog are usually converted to each other, and if the air humidity increases, haze can be converted to fog and vice versa.
The Hangzhou Meteorological Observatory predicts that in the next two days, the ground near Hangzhou will be affected by the easterly airflow, and the humidity will increase, and fog will easily form around the morning, and the humidity will decrease during the day, and the fog will turn into haze. Whether it is fog or haze, it is a manifestation of reduced air quality, and it will also reduce visibility.
The Zhejiang Provincial Meteorological Observatory predicts that the atmospheric diffusion conditions in our province will be poor from the 27th to the 30th, and there will be fog and haze in most areas. From the second half of the night to the morning tomorrow, there will be heavy fog and local dense fog in some areas of northern Zhejiang, coastal areas and southwest Zhejiang, including individual strong dense fog in Jiaxing, Ningbo and Taizhou.
While everyone goes out, they should pay attention to cold protection and keep warm, and also do a good job of health protection. Friends with allergies should reduce going out around the morning.
At the end of the month, the wind will cool down
From the 30th to the 31st, under the influence of the southwest warm and humid airflow and cold air, it is expected that there will be a cooling, weak precipitation and windy weather process in the province, and there will be 8-10 northerly gales on the coastal sea. The precipitation process is fleeting, and it is expected that the rain will stop and turn cloudy to overcast on Saturday (30th) night.
In terms of temperature, the maximum temperature will show an upward trend from today, overall around 15 °C, of which the maximum temperature in some areas will reach the recent peak on the 30th, soaring to 20 °C.
Temperatures were lower on the morning of January 1 and 2. In the recent comparison of cold and warm switching, everyone should dress reasonably, pay attention to the weather forecast, and make good living and travel arrangements.
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Cover photography: The Walker