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Global Analysis - September 2003

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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 warmest on record for September 2003
Temperatures were much above average across Asia, the western U.S. and eastern Canada with below average temperatures across western Australia, Mexico and Alaska
Precipitation during September 2003 was above average in the northeastern U.S. and Venezuela, with drier than average conditions over southern India and Japan
Near average equatorial Pacific SSTs were indicative of near-neutral ENSO conditions

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. This is a break in the document

Introduction

The September 2003 mean temperature was above the 1988-2002 average across eastern Canada, Europe, Russia and Morocco as shown in the adjacent map of blended satellite and in situ data. Cooler than average temperatures occurred over the central portion of India, Alaska and the U.S.Ohio Valley. The mean position of upper level ridges of high pressure 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. For all Global map products see the Climate Monitoring Products page.

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Global Temperature Anomalies in September 2003

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September temperature anomalies calculated from the Global Historical Climatology Network data set of land surface stations (using a 1961-1990 base period) also show above average temperatures throughout Russia, the western U.S. and much of Asia. Monthly temperatures were 3-5°C (5.4-9°F) above the mean in many of these areas. Cooler than average temperatures were present throughout Mexico, the central Great Plains of the U.S. and parts of South Africa where monthly temperatures were as much as 2-4°C (3.6-7.2°F) below average.

Temperature

September

For September 2003, the global average land and ocean surface temperature was 0.58°C (1.04°F) above the 1880-2002 average, ranking as the warmest September in the period of record
Globally averaged land temperatures were second warmest on record, 0.68°C (1.22°F) above the long-term mean
Globally averaged ocean surface temperatures were 0.53°C (0.95°F) above the 1880-2002 mean, warmest on record for September 2003.

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September 2003 temperatures averaged across the Northern Hemisphere were warmest on record, 0.67°C (1.21°F) above the long term mean
Temperatures averaged throughout the Southern Hemisphere were third warmest, 0.50°C (0.90°F) above average

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January-September

For January-September 2003, the global average land and ocean surface temperature was 0.60°C (1.00°F) above the long term mean, third warmest
Globally averaged land temperatures were third warmest on record, 0.84°C (1.51°F) above the long-term mean
Globally averaged ocean surface temperatures were 0.43°C (0.77°F) above the 1880-2002 mean, second warmest for January-September 2003.
January-September 2003 temperatures averaged across the Northern Hemisphere were third warmest on record, 0.62°C (1.12°F) above the long term mean
Temperatures averaged throughout the Southern Hemisphere were third warmest, 0.46°C (0.83°F) above average

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Serial monthly global surface temperature departures with respect to a 1971-2000 mean are shown in the figure to the left
Globally averaged surface temperatures (land and ocean) have been warmer than the 1971-2000 average for the last 89 consecutive months

Precipitation

During September 2003, much above average precipitation fell across Mexico, portions of central India, southern Brazil and Uruguay, and the northeastern U.S.
Below average precipitation was observed in eastern Australia, the United Kingdom and the Carribean
Additional regional analysis can be found on the Global Hazards page

Global Precip Anomalies in September 2003

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ENSO SST Analysis

last week of the month's ENSO condtions Map

Click here for animated loop

Sea surface temperatures were near normal over much of the equatorial Pacific (as shown in the adjacent animation of weekly sea surface temperature anomalies), indicative of neutral ENSO conditions. A comprehensive summary of September 2003 ENSO conditions can be found on the ENSO monitoring page. For the latest advisory on ENSO conditions go to NOAA's Climate Prediction Center (CPC) and the CPC ENSO Diagnostic Discussion
Images of sea surface temperature conditions are available for all months to date during 2003 at the weekly sst page

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 September 2003, published online October 2003, retrieved on June 19, 2013 from http://www.ncdc.noaa.gov/sotc/global/2003/9.