Pacific Ocean from space, ISS image. This image was taken from the International Space Station (ISS) as it orbited some 378 kilometres above the Earth. The Sun is partially seen at top, and clouds are seen across the Pacific Ocean. At upper left, one particularly large thundercloud has formed, reaching up to the tropopause to form the characteristic anvil-shaped thunderhead. The tropopause, the boundary between the troposphere and the stratosphere, varies in height between 11 and 17 kilometres.