The Equatorial (Passat) countercurrent is a powerful countercurrent between the Northern Passat Current and the Southern Trade Pass , observed in the equatorial region around the globe in the Pacific , Atlantic and Indian oceans.
| Equatorial countercurrent | |
|---|---|
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| Oceans | Pacific Ocean , Atlantic Ocean , Indian Ocean |
Surface inter-trade winds in the Atlantic, Pacific and Indian oceans have been known since the 19th century. These currents are directed east against the prevailing winds and against the movement of the main surface currents. The trade wind countercurrents are caused by the transverse unevenness of the prevailing winds ( trade winds ), so their speed and flow rate fluctuate significantly, until they disappear, depending on the strength and uniformity of the winds.
In the mid-20th century, subsurface and even deep countercurrents were discovered. Including powerful equatorial subsurface countercurrents - the Cromwell Current in the Pacific and the Lomonosov Current in the Atlantic Oceans. Subsurface equatorial currents are caused by a pressure gradient and move in the form of a narrow stream to the east under the west-bound trade wind.
In the period of weakening trade winds, subsurface countercurrents can “come out” to the surface of the ocean and are observed as surface currents.