Why does it not snow in Shanghai?

20 16 0 1 month, the weather forecast for Shanghai is: sleet, with pure snow in the west and north. Although there are snowflakes in neighboring cities such as Hangzhou, Nanjing and Hefei, for Shanghainese, the snow at the beginning of 20 16 is too small, and only residents in some peripheral areas such as Qingpu, Jinshan and Songjiang really see snowflakes.

Snow in Shanghai is not accidental, but related to geographical location, heat island effect and other factors.

It is related to the geographical location of Shanghai facing the sea on three sides, the near-surface temperature slightly higher than that of Jiangsu and Zhejiang, the different wind directions near the surface and the urban heat island effect. Based on these considerations, the Shanghai Central Meteorological Observatory also emphasized in the forecast conclusion that the precipitation was mainly sleet.

In winter, the ocean temperature is higher than that on land. Even in Shanghai, the temperature in the southeast coastal areas is often higher than that in the western and northern inland areas. On a larger scale, the near-surface temperature in Shanghai will be slightly higher than that in most areas of Jiangsu and Zhejiang. The urban heat island effect also plays a role, just as the snow in Shanghai snows more in the outer suburbs.

Some citizens have long noticed that the temperature in Shanghai is basically above 0℃ on rainy and snowy days of 20 16 and 0 1. Instead, the temperature plummeted after the rain and snow. "If the ultra-low temperature catches up with the rain and snow a few days earlier, isn't it snowing?"

In fact, it's not that they didn't meet by chance, but that the strong cold air drove away the rain and snow. Wu Rui, chief service officer of the Municipal Meteorological Bureau, said that the rainy and snowy weather was caused by the intersection of cold air and warm and humid air. When cold air passes through the border, it firmly dominates, the conditions for the formation of rain and snow disappear, the rain and snow stop, and extreme low temperature will appear.

According to the average situation of the atmosphere, the temperature will drop by 0.6℃ every time the altitude rises 100 m, and the higher it is, the colder it will be. Although the near-surface temperature in Shanghai is higher than 0℃ in this rainy and snowy weather, it is lower than 0℃ at an altitude of 500 meters, which is also the reason why there will be snow at the top of Shanghai center.

People's Daily Online-Snow in Shanghai is not accidental, but related to geographical location, heat island effect and other factors.