National Geographic : 1984 Feb
El Nifio's footprint on the ocean shows up as a rapidwarmingof the sea surface that culminatedin December 1982 in a tongue of warm water stretching 8,000 miles alongthe Equator (shadesof blue, from dark to light, identify temperatures 1° 2°, 3°, and more than 4°C above normal). Darkest blue perimeters enclose areasof heavy rain.Black arrows show wind directionand speed; white arrows indicate the variation from normal. Every few years the / \winds (9), causing the patternbreaks down- surface current to reverse disastrouslyin 1982-83 (i ) and warm water to surge (diagram, above). The low toward South America in a moves eastward (7), and the phenomenon known as a high weakens (s). Trade Kelvin wave (ii). winds falter and are Since this generally replacedby east-blowing stableweather machine spans a quarterof the globe (inset), its collapse has far reachingeffects. The cause remains unknown, although El Niiio and the monsoon system may be so intricately linked that changes in one affect behavior of the other. El Nino's Ill Winds 163 ~I f~7 7_ ;_~X - "