One of the astronauts on duty at the International Space Station (ISS) photographed the view of the clouds around the island of Sumatra. The photo also shows the islands of Bangka and Belitung, the Java Sea, and the west coast of Kalimantan.
This photo was taken on July 18, 2021, with a Nikon D5 digital camera using a focal length of 35 millimeters. The image was taken by a member of the Expedition 65 crew.
Seen in this photo published on NASA's Earth Observatory page on November 7, 2021, the long, bright clouds created by a thunderstorm cast a dark shadow over the land and sea below.
The brightest zone of the Sun's reflection on the water (sunglint) highlights the narrow strait between Sumatra and the other islands. Singapore also appears hidden under a thunderstorm.
On the day this photo was taken, the wind was blowing from the northeast (right to left in the photo view). After crossing the Java Sea, humid air will rise due to the heat. Such heating most likely caused thunderstorms to form on every island.
"The crests of some storms are cut off by the wind to form clouds with a flat top surface, called runway clouds. Winds can extend runways across great distances, forming long, narrow tails," wrote Justin Wilkinson of NASA-JSC.
The large runway that starts over Bangka Island stretches for about 200 kilometers across Sumatra to the Indian Ocean. Another basic cloud forms where air is forced to rise over the high Mount Barisan on Sumatra's southwest coast (far left). Small cumulus clouds also formed over the Mentawai Islands outline (top left).
Cloud-free zone, appearing over the Java Sea and the Indian Ocean. Both zones lie downwind of the mainland (Kalimantan and Sumatra), with the air apparently descending to sea level on that day. The descending air usually suppresses cloud formation.
