FIG.5. Zonal mean temperature (deg C) 1997 w.r.t. 1971-90 Stratospheric data adjusted for instrumental biases since 1979 -0.25 .0.25 Degrees C Q4.4 Please document your statement that “The nine warmest years of the century have occurred in the past 11 years." A4.4 NOAA's National Climatic Data Center receives and archives data from land stations, ships of opportunity and NOAA satellites around the world. Based on these data and an extensive list of peer-reviewed articles, they have compiled statistics for global surface temperatures during the past century. The details of these data are provided on the NCDC home page at http://www.ncdc.noaa.gov/ol/climate/research/1997/climate97.html. sample of the information on the Web site is attached. NCDC/Climate Resources / Climate Research / Climate of 1997/Search / Help A 0.25 0.00 -0.25 -0.50 1997 was the warmest year of this century, based on land and ocean surface temperature data, reports a team of scientists from the National Oceanic and Atmospheric Administration's National Climatic Data Center in Asheville, NC. Led by the Center's Senior Scientist Tom Karl, the team analyzed temperatures from around the globe during the years 1900 to 1997 and back to 1880 for land areas. For 1997, land and ocean temperatures averaged three quarters of a degree Fahrenheit (F) (0.42 degrees Celsius (C)) above normal. (Normal is defined by the mean temperature, 61.7 degrees F (16.5 degrees C), for the 30 years 1961-90). The 1997 figure exceeds the previous warm year, 1990, by 0.15 degrees F (0.08 degrees C). The record-breaking warm conditions of 1997 continues the pattern of very warm global temperatures. Nine of the past eleven years have been the warmest on record. Land temperatures did not break the previous record set in 1990, but 1997 was one of the five warmest years since 1880. Including 1997, the top ten warmest years over the land have all occurred since 1981, and the warmest five years all since 1990. Land temperatures for 1997 averaged three quarters of a degree F (0.42 degrees C) above normal, falling short of the 1990 record by one quarter of a degree F (0.14 degrees C). Ocean temperatures during 1997 also averaged three quarters of a degree F (0.42 degrees C) above normal, which makes it the warmest year on record, exceeding the previous warm years of 1987 and 1995 by 0.3 of a degree F (0.17 degrees C). The warm El Nino event (depicted as Sea Surface Temperature Anomalies) contributed to the record warmth of the oceans this year. With the new data factored in, global temperature warming trends now exceed 1.0 degree F (0.55 degrees C) per 100 years, with land temperatures warming at a somewhat faster rate. "It is likely that the sustained trend toward increasingly warmer global temperatures is related to anthropogenic increases in greenhouse gases", Karl said. The analysis was based on separately examining land data using the Global Historical Climatology Network, ocean data using the National Centers for Environmental Prediction (NCEP) - Reynolds Sea Surface Temperatures (SST), blended with the United Kingdom Meteorological Office Long Term SST analysis and a global surface temperature index that combined the ocean and land data. See Also... • Anomaly Time Series (Land, SST, and Index) • Global Surface Temperature Anomalies • Lower Tropospheric and Lower Stratospheric Temperatures Additional Graphics • US Statewide Ranks of 1997 Temperature and Precipitation • Time Series Plot of Annual Precipitation for further information on the climate of 1997, contact: Robert Quayle NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4328 email: rquayle@ncdc.noaa.gov or Mike Crowe NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4328 email: mcrowe@ncdc.noaa.gov for further information on GHCN, contact: Thomas Peterson NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4328 email: tpeterso@ncdc.noaa.gov Top of Page NCDC/Climate Resources / Climate Research / Climate of 1997/Search/Help http://www.ncdc.noaa.gov/ol/climate/research/1997/climate 97.html Last Updated 26 Aug 98 by Catherine Godfrey cgodfrey@ncdc.noaa.gov Land- and Sea-Based Versus Satellite Temperature Measurements Q5. Your testimony on page 4 says that 1997 was the warmest year on record. However, the land-based temperature data upon which this claim is based do not comport with satellite data, which show a slight cooling trend (-0.05°C per decade) over the last 19 years in the layer from about 5,000 to 30,000 feet. In fact, 1997 was the 8th coolest year in the satellite record, just slightly less than the 19-year average. Q5.1 A5.1 How do you account for the divergence between the trends in landbased and satellite temperature records over the past two decades? Surface-based temperature measurements of the ocean, sea surface and land surface have been made for the last 110 years, and definitively show that the Earth has warmed by about 1 degree F over this time. Satellite records have only been available for the past 19 years. That is too short a time period to accurately detect long-term temperature trends, given the natural cycles (e.g. El Niño and solar radiation) and random events (e.g. volcanic eruptions) that affect the global climate. The somewhat longer weather balloon record of atmospheric temperatures does, like the surface record, show warming over the longer period while, like the satellite record, showing cooling over the shorter period. There are a number of reasons to expect the satellite record to be different from the surface record, including stratospheric ozone depletion. The satellite record, while covering the whole globe, is not a measure of surface temperature, but of the temperature of the atmosphere, integrated from 5,000 to 30,000 feet. Since we live at the surface level, the land-based measurements provide a more useful indicator of the temperature changes that are affecting ecosystems and human society. Further information: In 1979, researchers added measurements from satellite-mounted Microwave Sounding Units (MSUs) to their arsenal of global climate monitoring systems. Instead of measuring the surface temperature, these satellite instruments measure the temperature of the earth's atmosphere on a global scale. Specifically, the MSUS on the satellites are being used to calculate temperatures in two atmospheric layers: the lower troposphere, from 1-7 km above ground (or ~5,000 to 30,000 feet), and the lower stratosphere, which is between 17 and 21 km above ground. These layers of the atmosphere and the earth's surface differ in their patterns of |