Simple facts
Where is it? Indian Ocean, Hard Island [-53.116414344, 73.51793263]
What do you see in the photo? The rare flow of the Von Calman vortex chasing its hidden peak
Which satellite took the photo? Landsat 8
When did you take it? May 3, 2016
This impressive satellite image shows ten swirling “dark blanks” appearing on an uninhabited volcanic island in the Indian Ocean. The black spots are the result of atmospheric cloud vortices, but compared to most other examples of this phenomenon, they are oddly pronounced and significantly distorted.
Spinning Void is away from Heard Island, an unmanned Australian territory in the South Indian Ocean, about 900 miles (1,500 km) north of Antarctica. The cloudy land surface area is approximately 142 square miles (368 square kilometers).
On average, dark spots are about 8 miles wide (13 km) and the size decreases slightly as you move them, according to NASA’s Earth Observatory. They initially move northeasterly (from left to right) from the island.
You might like it
Rotating holes are the result of a phenomenon known as von Kalman vortices, which occur when a common wind encounters land, disrupts the airflow and creates a “double row of vortices that alternate and alternate rotational directions.” They are named after Theodore von Kalman, the Hungarian-American physicist who first described this natural phenomenon.
In this case, the vortex is created by Mawson Peak, with an active volcano at a height of 9,000 feet (2,700 meters) sitting in the heart of Hard Island.
Related: See all the best images of Earth from Space
Typically, von Kármánvortices creates a long path of swirling clouds that are caught up in the destroyed airflow. Cloudstreams are usually perfectly straight, such as a series of parallel vortex streams that emerged side by side from Africa’s Atlantic coast in 2015 (see above).
However, in this case the vortex appears to be bent almost 90 degrees midway through the stream. This change in direction is most likely caused by sporadic bursts of intense westerly winds, often blowing through the entire area around Hard Island at speeds above 50 mph (80 km/h), known as the “Fast 50s,” according to the Earth Observatory.
In most cases of Von Kármán Vortices, the resulting cloud trail is very faint, tracking subtle variations of invisible airflow, such as those observed on Guadalupe Island, Mexico in 2012, and those observed on top of Svalbard’s Bear Island in 2023.
However, in this photo, the faint trail is replaced by a series of concentrated holes or gaps within the cloud. This is probably due to very thick cloud coverage, which can only be destroyed at the center of each rotating section in the vortex stream.
Mawson’s peaks are smaller than most of the peaks that regularly produce Von Kármán Vortices, and it is slightly unusual for cloud swirls to appear there. However, Heard Island has produced more traditional vortex streams than it has seen in November 2015.
Source link
