THE WINDS OF TRADE
Have you ever been in the doldrums? This was a situation that the sailing captains of old had to avoid at all costs. It was when the wind would die down to nothing and they would have to sit around in the doldrums – the belt of low air pressure along the Equator – sails flapping, with no prospect of getting fresh food or water any time soon. Fortunately, this was a rare situation because the trade winds tend to blow reliably from the east at an angle to the Equator such that they bring air from higher latitudes to the equatorial "zone of convergence". Straddling the Equator, Indonesia sits within this zone, and the archipelago’s rainfall is governed by these winds, which blow alternately during the year to create opposite climatic conditions north and south of the Equator.
The reliability of the trade winds was the mainstay of traders from the East Indies (now known as the Indonesian archipelago). The steady alternation of these monsoon winds led to a trading rhythm, in which vessels caught the East Monsoon on their voyage from the archipelago to India and China and picked up the West Monsoon on their return. This change in wind direction meant that it was not possible to travel between India and China in a single season and the traders’ need to wait for a change of wind at the southern end of the South China Sea contributed to the emergence of major port cities in that region.
Even nowadays, commercial ships and cruise companies – SeaTrek included – use the trade winds and the currents that the winds produce to hasten and smooth their oceanic voyages.
The engine of the monsoon is the sun. In Bali, until the land sufficiently warms, the airflow aloft maintains an easterly flow. During the winter in the southern hemisphere, a stable high pressure system pushes air northwards and forces it to move towards the doldrums. The rotation of the earth deflects this airflow so that it reaches Bali from the southeast to produce our dry season. As the dry season progresses, solar radiation warms the land and the sea at different rates, inciting a tug-of-war with the winds. When the trade winds do an about-face, our rainy season begins and SeaTrek’s itineraries move from Bali and Komodo to enjoy predominantly dry weather north of the Equator in Raja Ampat and the Maluku Islands.
