Contact: Stephanie Kenitzer FOR IMMEDIATE RELEASE
(301) 713-0622 1/12/95
Near record warm global temperatures and the return of El Nino in the tropical Pacific are the climate highlights of 1994, say scientists at the National Oceanic and Atmospheric Administration's National Weather Service in a preview to the agency's annual Climate Assessment report.
After two relatively cooler years, the estimated mean global temperature (land only) was 0.4 degrees Celsius above normal during 1994 -- similar to record levels that were first observed in 1990 and 1991. In 1994, most of the warmth occurred after February -- global temperatures from March to December were the warmest observed since 1951.
"We've been looking for changes in the mean global temperature since the decrease after the Mt. Pinatubo eruption in 1991," said David Rodenhuis, director of the Climate Analysis Center at the NWS National Meteorological Center in Camp Springs, Md. "We've seen the positive anomalies return in the spring of 1994 with records set in September and December."
El Nino conditions, characterized by the warming of ocean surface temperatures in the tropical central and eastern Pacific, returned in 1994. Throughout the year, equatorial ocean temperatures became increasingly warmer than normal everywhere east of the International Date Line. The Northern Hemisphere is currently experiencing the third winter season in four years to be influenced by the abnormally warm waters. This is unprecedented during the past 50 years.
During the past 15 years, ozone depletion of 30 to 50 percent has been observed by scientists over the south polar region. Extremely low values of total ozone -- near 100 Dobson Units -- were measured over Antarctica during October 1994, when the Antarctic ozone hole was observed. Dobson units are the standard way to express ozone amounts in the atmosphere.
In the contiguous United States, the mean temperature in 1994 was much above the long-term mean (52.5 degrees Fahrenheit, 11.4 degrees Celsius). In addition, 1994 ranked as the 16th warmest year on record, according to preliminary annual temperature data. More than 25 percent of the nation averaged much warmer-than-normal temperatures, while none of the country was much colder-than-normal. During 1994, although unusually cold conditions characterized February, unusually warm conditions were dominant during March, June and December.
Two major flood events occurred in the United States in 1994. In July, Tropical Storm Alberto brought torrential rainfall and produced record flooding along portions of several large river systems in Georgia, Alabama and Florida. In October, Southeast Texas was deluged with rainfall exceeding 30 inches accumulation in a three-day period at some locations, which caused record flooding along six major rivers and their tributaries.
The 1993/94 wet season (October - April) brought below normal precipitation to much of the western United States, with large portions receiving less than 50 percent of normal. However, precipitation at the onset of the 1994/95 wet season averaged above normal over much of eastern and southern Washington, western and central Oregon and northern and central California. At the end of 1994, drought conditions had been greatly reduced across large parts of the West.