An enormous oval hole, several hundred miles across, in the clouds above the southern Pacific Ocean, acquired by NASA’s Aqua satellite on June 5, approximately 500 miles (800 km) off the southwestern coast of Tasmania. Image credit: NASA/Aqua
The hole is the result of high pressure air in the upper atmosphere.
According to Rob Gutro of NASA’s Goddard Space Flight Center, “This is a good visible example of how upper-level atmospheric features affect the lower atmosphere, because the cloud hole is right under the center of a strong area of high pressure. High pressure forces air down to the surface blocking cloud formation. In addition, the altocumulus clouds are rotating counter-clockwise around the hole, which in the southern hemisphere indicates high pressure.”