Trade winds Fontaine Maury collected enough information to create wind and current charts for the world's oceans. As part of the Hadley cell, surface air flows toward the equator while the flow aloft is towards the poles. A low-pressure area of calm, light variable winds near the equator is known as the doldrums, near-equatorial trough, intertropical front, or the Intertropical Convergence Zone. When located within a monsoon region, this zone of low pressure and wind convergence is also known as the monsoon trough. Around 30° in both hemispheres, air begins to descend toward the surface in subtropical high-pressure belts known as subtropical
1987–88 South Pacific cyclone season New Zealand Meteorological Service, while the United States Joint Typhoon Warning Center and Naval Pacific Meteorology and Oceanography Center also monitored the region. During December 1987, the South Pacific Convergence Zone started to intensify as upper level westerly winds appeared near the equator, with two depressions forming near Tuvalu towards the end of December as a result. Despite the low-level conditions being ideal for the development of a tropical cyclone at this stage, the surrounding upper-level conditions were unfavourable and the depressions dissipated while still in the low-latitudes. Tropical Cyclone 04P was monitored near Tuvalu, by the JTWC and the