Monsoon trough of the summertime Asian monsoon is in its normal orientation (oriented east-southeast to west-northwest), tropical cyclones along its periphery will move with a westward motion. If it reverses its orientation, orienting southwest to northeast, tropical cyclones will move more poleward. Tropical cyclone tracks with S-shapes tend to be associated with reverse-oriented monsoon troughs. The South Pacific convergence zone and South American convergence zones are generally reverse oriented. The failure of the monsoon trough, or the ITCZ, to move south of the equator in the eastern Pacific Ocean and Atlantic Ocean during the southern hemisphere summer, is considered one of the
Rockall Basin (also known as the "Hatton Rockall Basin"). In 1956 the British scientist James Fisher referred to the island as "the most isolated small rock in the oceans of the world". The neighbouring Hasselwood Rock and several other pinnacles of the surrounding Helen's Reef are smaller, at half the size of Rockall or less, and equally remote, but those formations are legally not islands or points on land, as they are often submerged completely, only revealed momentarily above certain types of ocean surface waves. Rockall is about wide and long at its base and rises sheer to a height of