At noon on January 12, as a polar-orbiting satellite skimmed east of East Asia, a bizarre scene was captured in the East China Sea east of Shanghai— the spiral system south of Jeju Island was particularly noticed among the dense clouds south of South Korea. The clouds here twist and stagger into a unique spiral shape that looks like small whirlwinds connected together.
In addition to the vicinity of Jeju Island, the satellite also captured a similar cloud belt near Yakushima Island, south of Kyushu Island in Japan— twisted clouds extending from near Yakushima Island and extending in a southeasterly direction toward the depths of the Pacific Ocean, forming a twisted cloud belt, like a coiled "bubble noodle". Then some netizens have to ask: Is the simultaneous appearance of this strange "bubble noodle" cloud system in Japan and South Korea a precursor to a wide range of weather changes? Some netizens even doubted: Is this an earthquake cloud?
In fact, behind this particular phenomenon is a physical principle - Carmen Vortex Street. In 1912, the physicist Theodore von Kármán first described this phenomenon and got its name, referring to the blocking fluid placed in the fluid, under certain conditions there will be an unstable boundary layer separation, the two sides of the downstream of the obstructive fluid, will produce two asymmetrically arranged vortexes, one side of the vortex rotates in the clockwise direction, the other vortex rotates in the opposite direction, the two rows of vortexes are staggered with each other, each vortex and the middle point of the opposite two vortexes are aligned, Like the street lights on both sides of the street, it is called Vortex Street.
In today's East Asia, whether near Yakushima Island in Japan or near Jeju Island in South Korea, this special cloud band formed in the clouds is an external manifestation of Carmen Vortex Street. Carmen Vortex Street requires stable, moderate wind speeds to form in its back after circling the terrain of a certain scale – there is a Highlander Mountain at an altitude of 1947 meters on Jeju Island in South Korea, and Yakushima Island is also a mountainous island, with mountains accounting for about 75% of the island's total area and an average height of more than 1000 meters, which acts as a barrier fluid in the atmosphere of today's East Asia.
From the Fengyun-4 high-definition visible light satellite cloud map at noon on January 12, when there are still cold clouds covering many places in the central and eastern parts of China today, in the deep Pacific Ocean in the eastern sea area of China, the Sea of Japan, and the east of the Ryukyu Islands and southeast of Japan, a large number of cold flow clouds flow to the Pacific Ocean like bubbles, and like quicksand, which means that the cold air dumped from Eurasia has been released into the Pacific Ocean in large quantities, announcing that the last cold air has completely moved south in East Asia. In this cold cloud formed by the cold air mass after moving south, the relatively stable wind speed has formed a number of Carmen vortex streets under the interference of the island's terrain.
From previous observations, Jeju Island may be the most prone area in East Asia to this phenomenon. During the winter period when the cold air masses go south, Jeju Island often produces the phenomenon of Carmen Vortex Street, and even sometimes the vortex in Carmen Vortex Street will be particularly obvious, it is clear that from the principle of formation, this phenomenon has nothing to do with earthquakes, but corresponds to the roar of cold air masses to the south.
In January 2017, Carmen Vortex Street appeared south of Jeju Island in South Korea