Global Analysis - August 2002

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Note: GHCN-M Data Notice

An omission in processing a correction algorithm led to some small errors on the Global Historical Climatology Network-Monthly dataset (GHCN-M v3.2.0). This led to small errors in the reported land surface temperatures in the October, November, December and Annual U.S. and global climate reports. On February 14, 2013, NCDC fixed this error in its software, included an additional improvement (described below), and implemented both changes as GHCN-M version 3.2.1. With this update to GHCN-M, the Merged Land and Ocean Surface Temperature dataset also is subsequently revised as MLOST version 3.5.3.

The net result of this new version of GHCN-M reveals very small changes in temperature and ranks. The 2012 U.S. temperature is 0.01°F higher than reported in early January, but still remains approximately 1.0°F warmer than the next warmest year, and approximately 3.25°F warmer than the 20th century average. The U.S. annual time series from version 3.2.1 is almost identical to the series from version 3.2.0 and that the 1895-2012 annual temperature trend remains 0.13°F/decade. The trend for certain calendar months changed more than others (discussed below). For the globe, ranks of individual years changed in some instances by a few positions, but global land temperature trends changed no more than 0.01°C/century for any month since 1880.

NCDC uses two correction processes to remove inhomogeneities associated with factors unrelated to climate such as changes in observer practices, instrumentation, and changes in station location and environment that have occurred through time. The first correction for time of observation changes in the United States was inadvertently disabled during late 2012. That algorithm provides for a physically based correction for observing time changes based on station history information. NCDC also routinely runs a .pairwise correction. algorithm that addresses such issues, but in an indirect manner. It successfully corrected for many of the time of observation issues, which minimized the effect of this processing omission.

The version 3.2.1 release also includes the use of updated data to improve quality control and correction processes of other U.S. stations and neighboring stations in Canada and Mexico.

Compared to analyses released in January 2013, the trend for certain calendar months has changed more than others. This effect is related to the seasonal nature of the reintroduced time-of-observation correction. Trends in U.S. winter temperature are higher while trends in summer temperatures are lower. For the globe, ranks of individual years changed in some instances by a few positions, but global temperature trends changed no more than 0.01°C/century for any month since 1880.

More complete information about this issue is available at this supplemental page.

NCDC will not update the static reports from October through December 2012 and the 2012 U.S and Global annual reports, but will use the current dataset (GHCN-M v. 3.2.1 and MLOST v. 3.5.3) for the January 2013 report and other comparisons to previous months and years.

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Global Highlights:

  • Global average combined land and sea surface temperature in 2002 was the third warmest on record for June-August
  • June-August temperatures were 3-5°C (5.4-9°F) warmer than average over much of Europe and eastern Russia, as well as parts of the U.S.
  • Above average precipitation during June-August occurred across central Europe, Korea, southeast China and the U.S. Gulf Coast, while below average precipitation was noted across India, Australia and the western and eastern U.S.
  

Contents of this Section:
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The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. The most current data may be accessed via the Global Surface Temperature Anomalies page.
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Top of Page Introduction

The June-August 2002 mean temperature was above the 1988-2002 average across much of the United States, nearly all of Europe, and from India northward through China and eastern Russia as shown in the adjacent map of blended satellite and in-situ data. Cooler than average temperatures occurred across Argentina, central Russia and Japan. The mean position of upper level ridges and troughs of low pressure (depicted by positive and negative 500 millibar height anomalies), are generally reflected by areas of positive and negative temperature anomalies at the surface, respectively. Warmer-than-average sea surface temperatures developed throughout the tropical Pacific during June-August, the signature of El Niño conditions. The Global Blended Temperature in June-August 2002
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The Global Temperature Anomalies in August 2002
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 August temperature anomalies calculated from the Global Historical Climatology Network data set of land surface stations using a 1961-1990 base period show below average temperatures in southeast China, Japan and Korea and in the northwest U.S. Notable warm anomalies were present across central Europe and the eastern two-thirds of the United States.
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Top of Page Temperature

June-August
  • The global land and ocean surface temperature average (June-August 2002) was the third warmest such 3-month period in the 1880-2002 record, 0.47°C (0.85°F) above the long-term mean and 0.16°C (0.29°F) cooler than during the El Niño year of 1998
  • June-August 2002 average temperature across land areas ranks as third warmest on record, or 0.69°C (1.24°F) above the 1880-2001 average
 The Global Temp Anomalies in June-August 2002
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August
  • For August 2002, the global average land and ocean surface temperature was 0.41°C (0.74°F) above the 1880-2001 average, ranking as the fifth warmest August in the period of record
  • The warmest August occurred 4 years ago during the last record warm boreal summer
  • The August ocean surface temperature average was fourth warmest on record, 0.37°C (0.67°F) above average
 The Global Temp Anomalies in August 2002
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  • Serial monthly global surface temperature departures with respect to a 1971-2000 mean are shown in the figure to the right
  • The recent return to record or near record temperature departures is evident, and globally averaged surface temperatures (land and ocean) have been warmer than the 1971-2000 average for the last 76 consecutive months
 The Global Temperature Timeseries
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Top of Page Precipitation

  • During June-August 2002, much above average precipitation fell across central Europe, Korea, southeast China and the U.S. Gulf Coast
  • Below average precipitation was observed across the eastern and wester United States, the eastern Caribbean and much of India, where monsoon rainfall was unusually light
  • August precipitation was above average across central Europe, Korea and South Africa
  • Additional regional analysis can be found on the Global Hazards page
 The Global Precip Anomalies in June-August 2002
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References:

Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global Historical Climatology Network Database. Bull. Amer. Meteorol. Soc., 78, 2837-2849.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: Global Analysis for August 2002, published online September 2002, retrieved on June 19, 2013 from http://www.ncdc.noaa.gov/sotc/global/2002/8.