抄録
El Niño-A global weather phenomenon was observed since March 1997. Equatorial sea surface temperature (SST) anomalies (departures from normal) greater than +2.5°C were observed along the equator east of 110°W in June ; SST anomalies in the Niño regions in 1997 have been the largest August and September values observed in the last 50 years. NASA Scatterometer (NSCAT) aboard Japan's Advanced Earth Observing Satellite (ADEOS, Midori) continually observed the global ocean surface wind speed and direction from September 1996 to June 1997. These easterly winds began to weaken from March. Since then, weaker than normal easterly winds have been observed across most of the equatorial Pacific. Wind shifted to westerly in the equator west of about 140°W in June 1997. The intraseasonal variations of zonal wind component are important during the El Niño onset period.
