It will snow in the hottest Sahara desert in the world. Why does it snow in Africa?

In recent years, extreme weather has occurred frequently all over the world, and we can always see snowfall in some hot countries all the year round, which is not equal to the snowfall in Hainan, China. According to the latest news from the World Meteorological Organization, it snows in the hottest Sahara desert in the world! It snows in Africa? In fact, it is not the first time that it snows in Africa! So why does it snow in Africa? Let's get to know each other.

It will snow in the hottest Sahara desert in the world.

According to the World Meteorological Organization (WMO) in official website, the northeastern part of Libya recently suffered from extreme weather, which not only snowed, but also caused heavy rainfall and even hail in some areas. Snow in Africa sounds a bit surprising, and Libya, a North African country next door to Egypt, is still located in the northern Sahara desert. It seems unbelievable to hear that it is snowing.

Let's talk about why it snows in Libya:

Libya is really not a place prone to snow. As a country where more than 95% of its territory is desert and semi-desert, most of Libya has a dry subtropical desert climate, and only some coastal areas in the north have a Mediterranean climate. The Qingshan area where snowfall occurred this time (that is, the Al‐Jabal Al‐Akhdar area mentioned in the original text) has a typical Mediterranean climate.

As can be seen from the relevant monitoring figures, this area is not completely dry and rainless in our memory, and there is still precipitation. The key factor that determines rain and snow is temperature.

It snowed this time because Libya suffered from "extreme weather". On the 500hPa wind map of1+65438+February 19, it can be seen that a deep trough leads the polar cold air mass to the south, affecting the Mediterranean coast, bringing about obvious cooling, and also carrying water vapor from the Atlantic Ocean and the Mediterranean Sea.

Looking at this satellite cloud image in WMO official website News again, we can see that there are obvious cold snap clouds over the northeast of Libya, so this snowfall is likely to be a cold snap snowfall, and the Green Mountain area where snowfall occurs is just the terrain favorable for cold snap snowfall-it is a mountainous area with an average elevation of 600 meters.

So to sum up the snowfall in Libya, it is likely that the cold air with water vapor passed through the relatively warm Mediterranean and was lifted by the terrain in the Green Mountain area, resulting in a cold current snowfall.

Why does it snow in Africa?

In addition to Libya this time, Cameroon near the equator also caught fire last year because of "snow". Previously, the snow in the Sahara desert at the beginning of last year also made many netizens shout "live for a long time". The question is, why does it always snow in Africa, which seems impossible?

Not to mention, it is more likely that it snowed in Cameroon last time than in the Sahara desert, and it did snow more than once. As early as 20 18, some media reported the "anecdote" of snow in the Sahara desert, and even the local snowfall occurred for the third consecutive year.

The places where it snows in the Sahara desert these days are all towns in Algeria, called Ain Cebra. As we couldn't find the local meteorological data, we found a desert city nearby, Bechar, as a reference.

Although it is located in the Sahara desert, the average minimum temperature in winter in 65438+ 10 can be as low as 3.5℃, which is much colder than that in Guangzhou!

Looking back at the 500hPa map of the Ainse Bra Snow Day in 20021+17, we can see that there was also an upper trough touching the Algerian sky at that time, and the north wind and west wind behind the trough brought water vapor from the Atlantic Ocean, and the cold air cooled down+precious water vapor, which provided conditions for this snowfall in the Sahara.

Seeing this, everyone will understand that it is not necessarily hot every day in Africa, and it is not necessarily a hot desert in Sahara. There is also winter in Africa, and it may snow in extreme weather.

However, we should also pay attention to the fact that the desert areas where it is difficult to snow appear in newspapers more and more frequently because of snowfall, which is evidence that extreme weather occurs more and more frequently around the world.

Climatic characteristics of Sahara desert;

The climatic conditions are extremely bad, which is one of the most unsuitable places for biological growth on earth. Sahara means "big desert" in Arabic. Sahara Desert (English name: Sahara desert) is the most sunny place in the world, and it is also the largest desert with the worst natural conditions in the world.

The climate of the Sahara desert is controlled by the north-south transition of the trade winds, and there are often many extreme situations. It has the highest evaporation rate in the world, and has the largest area record of no rain for several years. At high altitude, the temperature can reach frost and freezing, while at low altitude, the hottest weather in the world can be found.

The Sahara desert divides the African continent into two parts, North Africa and Southern Black Africa. The climate and culture of these two parts are completely different. The southern border of the Sahara desert is semi-arid savanna, which is called "Sahel" in Arabic, and then it is called "Sudan" in Arabic, which means black Africa.

The Sahara desert is dominated by two climatic conditions: the arid subtropical climate in the north and the arid tropical climate in the south. The arid subtropical climate is characterized by large annual and daily temperature changes, from cold to cool winter and hot summer to the highest precipitation.

The annual average daily temperature is about 20℃(68℉). The average temperature in winter is 13℃(55℉). It is very hot in summer. The highest temperature in Al-Aziziyah, Libya reached a record 58℃( 136℉). The annual precipitation is 76 mm (3 inches). Although the rainfall varies greatly, most of it occurs during 65438+February ~ March. Another precipitation climax is August, which is characterized by thunderstorms.

This kind of rainstorm will lead to huge flash floods and rush into areas where there is no rain. The characteristics of arid tropical climate are that with the change of the position of the sun, the annual temperature cycle is strong; Mild and dry winter and hot and dry season are followed by changeable summer rain. The annual average daily temperature difference in the arid tropical region of the Sahara desert is 17.5℃(3 1.5℉).

The average temperature in the coldest month is basically the same as that in the northern subtropical region, and sometimes the daily temperature difference is particularly large. At a weather station south of Tripoli, North Africa,1February 25th, 978, the highest temperature in Jedaias during the day was 37.2℃, but the lowest temperature at night dropped to -0.6℃, and the daily temperature difference reached 37.8℃, which was really "wearing a fur coat at noon". It is bone-chilling cold at night (although -0.6℃ is not cold, the temperature difference reaches 37.8℃, and it can be imagined that it is cold from extremely hot to extremely cold). It is very hot in late spring and early summer, and the high temperature of 50℃( 122℉) is not uncommon.

Although there is little precipitation in arid tropical hills all year round, the summer rainfall in lowlands can reach the highest. In the north, this kind of rainfall mostly appears in the form of thunderstorms. The average annual precipitation is about 125 mm (5 inches), and sometimes it snows in the central hills.

The cold canary airflow on the western edge of the desert reduces the temperature, thus reducing the convective rain, but sometimes fog appears when the humidity increases. Winter in the south of the Sahara desert is a period when Hamdan wind blows, which is a dry northeast wind with sand and other small dust particles.