Global Analysis - March 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 was the warmest on record for March
  • Lower tropospheric temperatures were warmer than average
  • March temperatures were greater than 4°C (7.2°F) above average from eastern Europe to the Russian Far East
  • Above average precipitation was most notable across northern Argentina and Uruguay, with below average precipitation across much of Australia and Brazil
  

Contents of this Section:
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Top of Page Introduction

Using a 1992-2002 base period as shown in the adjacent blended temperature product of satellite and in-situ data, an expansive area of anomalous warmth during March was dominant across Asia. Cooler temperatures relative to average were observed across parts of North America, from the Canadian prairies southward into the plains of the United States. The mean position of upper level ridges and troughs of low pressure (depicted by positive and negative 500 millibar height anomalies), correspond to areas of positive and negative temperature anomalies, respectively. During March 2002, conditions in the tropical Pacific continued to indicate a developing El Niño episode. Click Here for the Global Blended Temperature in March 2002
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Click Here for the Global Temperature Anomalies in March 2002
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 Temperature anomalies calculated from in-situ station data using a 1961-1990 base period also show the warmer than average temperatures across Asia, Europe and Alaska with cooler than average temperatures over central North America, central Australia and southern Argentina and Chile.
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Top of Page Temperature

  • Although surface temperatures in the tropics have not reached the warmth observed during the latter stages of the 1998 El Niño episode, the global land and ocean temperature in March 2002 was the warmest in the 1880-2002 record, 0.77°C (1.39°F) above the long-term average
  • Temperatures averaged across land areas were second warmest on record globally, or 1.50°C (2.70°F) above the long-term March mean
  • For the period January through March, combined land and ocean temperatures tied with the El Niño year of 1998 as warmest on record, 0.72°C (1.30°F) above the mean
  • Land areas experienced record warmth during the period January-March, or 1.39°C (2.50°F) above the 1880-2001 average
 Click Here for the Global Temp Anomalies in March 2002
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Click Here for the Global Temperature Anomalies for October 2001-March 2002
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  • Based on data available at the time of this report, the global average land and ocean temperature for the period October 2001-March 2002 was 0.63°C (1.13°F) above the 1880-2001 mean, the second warmest such period on record
  • Record high global monthly temperatures were established in January 2002 and November 2001
  • 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 monthly global temperatures (land and ocean) have been warmer than the 1971-2000 average for the last 71 consecutive months
 Click Here for the Global Temperature Timeseries
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Top of Page Precipitation

  • During March, much above average precipitation fell across parts of northern Argentina, Uruguay and the U.S. Tennessee Valley
  • Drier than average weather prevailed across much of Australia, Brazil, western Europe and much of the central and western U.S.
  • Additional regional analysis can be found on the Global Regional page
 Click Here for the Global Precip Anomalies in March 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 March 2002, published online April 2002, retrieved on June 20, 2013 from http://www.ncdc.noaa.gov/sotc/global/2002/3.