EL NINO IMPACTS ON COTTON YIELDS

摘要

The weather phenomenon known as El Nino refers to abnormal water temperatures in the tropical Pacific. During an El Nino, Pacific trade winds are weaker than usual, allowing warm water to remain on the ocean surface off the West coast of Peru ratherthan being replaced by upwelling cold water, An El Nino is defined as occurring when the water temperature in the Pacific along the equator is one standard deviation or about one degree centigrade, warmer than normal for at least one month. Since 1950, ElNino events have occurred twelve times, or roughly once every four years, the most recent beginning in April 1997. The El Nino which began in June 1982 is considered particularly severe because water temperatures in the Pacific rose four degrees above average. In 1997, water temperatures in the Pacific have risen to 2.5 degrees above average and might still be climbing, making this El Nino the second or third strongest.