Global Analysis - December 2012
Contents of this Section:
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.
- The average combined global land and ocean surface temperature for December 2012 was the 18th warmest December since records began in 1880, at 0.41°C (0.74°F) above the 20th century average of 12.2°C (54.0°F).
- The globally-averaged land surface temperature for December 2012 was the 49th warmest December on record, at 0.21°C (0.38°F) above average. The globally-averaged ocean surface temperature was the sixth warmest December on record, at 0.47°C (0.85°F) above average.
- The average combined global land and ocean surface temperature for January–December 2012 was the 10th warmest such period on record, at 0.57°C (1.03°F) above the 20th century average.
Temperature anomalies and percentiles are shown on the gridded maps below. The anomaly map on the left is a product of a merged land surface temperature (Global Historical Climatology Network, GHCN) and sea surface temperature (ERSST.v3b) anomaly analysis developed by Smith et al. (2008). Temperature anomalies for land and ocean are analyzed separately and then merged to form the global analysis. For more information, please visit NCDC's Global Surface Temperature Anomalies page. The December 2012 Global State of the Climate report introduces percentile maps that complement the information provided by the anomaly maps. These new maps on the right provide additional information by placing the temperature anomaly observed for a specific place and time period into historical perspective, showing how the most current month, season or year compares with the past.
In the atmosphere, 500-millibar height pressure anomalies correlate well with temperatures at the Earth's surface. The average position of the upper-level ridges of high pressure and troughs of low pressure—depicted by positive and negative 500-millibar height anomalies on the December 2012 map—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.
The December 2012 globally-averaged temperature across land and ocean surfaces was 0.41°C (0.74°F) above the 20th century average of 12.2°C (54.0°F), tying with 1990 and 1994 as the 18th warmest December since records began in 1880 and the coolest December since 2000. This anomaly is significantly lower than the record December warmth of 2003 and 2006, which was 0.75°C (1.35°F) above average.
The global land surface temperature anomaly was 0.21°C (0.38°F) higher than average, the 49th warmest on record for the month of December. It was the coolest December for land surfaces since 1986 and the largest cool temperature anomaly of any month since November 2000. There was sharp contrast between the Northern and Southern Hemisphere land temperatures, with the Southern Hemisphere record warm and the Northern Hemisphere colder than average (-0.07°C / -0.13°F anomaly) for the first time since November 2000, ranking 64th coolest (70th warmest) in the 133-year period of record. For comparison, the average land surface temperature in the Northern Hemisphere for each of the previous eight months (April–November) ranked among the top eight for their respective months. The Northern Hemisphere mid-latitudes (30°N–60°N)—where the majority of the world's human population resides—was 0.70°C (1.26°F) below the 20th century average, the 31st coldest December on record and the coldest December in this latitude belt since 1984.
It was notably colder than average across much of Eurasia, western Canada, and Alaska. As shown by the temperature anomalies map above, December temperatures were more than 5°C (9°F) below the 1981–2010 average across central Asia, parts of western Canada, and eastern Alaska.Select national information is highlighted below:
- Through December, Russia experienced its coldest winter to date since 1938, with temperatures as much as 10°–15°C (18°–27°F) below average. Temperatures fell to as low as -50°C (-58°F) in Siberia.
- According to the China's National Climate Center, from late November through early January, northern and eastern China experienced its coldest temperatures in 28 years for this time of year. The capital city of Beijing observed its lowest average temperature for the period (-6.4°C / 20.4°F) since at least 1951.
- December was colder than average across all of Sweden. The far north experienced its coldest December since 1986, according to the Swedish Meteorological and Hydrological Institute.
- The Finish Meteorological Institute reported that December temperatures were well below average, with anomalies ranging from -3° to -5°C (-5.4° to -9°F) across most of the country. The eastern central region experienced temperatures more than 5.5°C (9.9°F) below average.
- Norway experienced its 11th coolest December since national records began in 1900, at 2.6°C (4.7°F) below average, according to Meteorologisk institutt. The coolest anomalies occurred in the mountains of southern Norway where temperatures were 5°–7°C (9.0°–12.6°F) colder than average.
- In contrast with November, which had above-average temperatures engulfing the country, most of Hungary was colder than average during December. Temperatures were up to 3°C (5.4°F) below the 1971–2000 average.
- Average December temperatures across the Republic of Moldova were 2°–4°C (3.6°–7.2°F) below the long-term average. According to Serviciul Hidrometeorlogic de Stat, this is an event that occurs every 5 to 10 years.
- The U.S. state of Alaska observed its 18th coolest December since records began in 1918. The average monthly temperature was 3.3°C (5.9°F) below the 1971–2000 average.
It was warmer than average across eastern North America, most of South America, southern Asia, Australia, and southern Greenland. Record warmth was observed in southern Brazil, parts of northwestern Australia, and some regions near the equator. The average December temperature was more than 5°C (9°F) above average in part of southeastern Greenland.
- For the second month in a row, the nationally-averaged monthly maximum temperature across Australia was the fourth highest in the 103-year period of record, with the December temperature 1.23°C (2.21°F) above the 1961–1990 average. Also for the second month in a row, no state or territory reported below-average maximum or minimum average temperatures.
- The average December temperature across New Zealand was 1.1°C (2.0°F) above the 1971–2000 average, according to the National Institute of Water and Atmospheric Research (NIWA). Many record or near-record monthly temperatures were observed across the North Island, around Nelson, and parts of the eastern South Island.
The December 2012 globally-averaged ocean temperature anomaly of 0.47°C (0.85°F) was the sixth warmest on record for December. For the ninth straight month, ENSO-neutral conditions persisted in the central and eastern equatorial Pacific Ocean, with sea surface temperatures slightly above average in the western Pacific, near average in the central Pacific, and slightly below average in the eastern Pacific. According to NOAA's Climate Prediction Center, neutral conditions are favored to continue through the Northern Hemisphere spring 2013. In other regions, it was notably warmer than average in the north central and northwestern Pacific Ocean, most of the Indian Ocean, the eastern and central Atlantic Ocean, and parts of the mid-latitude southern oceans. Associated with a persistent negative phase of the Pacific Decadal Oscillation, temperatures were cooler than average across the northeastern Pacific Ocean. Images of sea surface temperature conditions are available for all weeks during 2012 from the weekly SST page.
Global surface temperature stats are not currently available for December 2012.
The January–December map of temperature anomalies shows that warmer-than-average temperatures occurred across much of the globe during 2012. Global temperatures were influenced by a weak-to-moderate La Niña event at the beginning of the year that transitioned to ENSO-neutral conditions by April, along with global land surface temperatures from April to November that ranked among the top eight for their respective months. Overall, the worldwide combined land and ocean surface temperature was 0.57°C (1.03°F) above the 20th century average, ranking 2012 as the 10th warmest year on record. This temperature anomaly is 0.09°C (0.16°F) less than the record warmth of 2010. Separately, the 2012 average global land surface temperature ranked as the seventh warmest on record and the ocean surface tied with 2001 as the 10th warmest.
Record warmth was observed across much of central North America, central South America, parts of southern and eastern Europe, much of the northeastern coastal Atlantic Ocean, part of the southern Arctic Seas, and sections of the mid-latitude Southern oceans. Also noteworthy, it was much warmer than average across most of North and South America, central and southern Europe, much of northern and coastal Africa, and western, southern, and far northeastern Asia. Temperatures were cooler than average across most of Alaska, part of the northeastern and east central Pacific Ocean, and the Southern Ocean off the southern tip of South America. No record cold regions were observed for the January–December 2012 period. Please refer to the NCDC State of the Climate Annual Global Analysis report for more detailed information.
Global surface temperature stats are not currently available for December 2012.
The most current data may be accessed via the Global Surface Temperature Anomalies page.
Images of sea surface temperature conditions are available for all weeks during 2012 from the weekly SST page.
The maps below represent precipitation percent of normal (left) and precipitation percentiles (right) based on the GHCN dataset of land surface stations using a base period of 1961–1990. As is typical, precipitation anomalies during December 2012 varied significantly around the world.
- Averaged across the country, the Netherlands received 125 mm (4.92 inches) of rainfall during December, 160 percent of normal for the month.
- December rainfall in Norway was 70 percent of average, marking the 15th driest December on record for the country.
- According to the UK Met Office, precipitation totals for the UK on average were 150% of the long-term average, making this the wettest December since 1999 and the eighth wettest since records began in 1910.
Tropical cyclones rarely hit the southern Philippines; however, Category 5 Super Typhoon Bopha struck southern Mindanao Island in early December, dumping copious rainfall over the region, killing more than 900 residents, and leaving more than 600 missing. This is the same region where Tropical Storm Washi hit just one year earlier, in December 2011, killing more than 1300 people.
Additional details on flooding and drought events around the world can also be found on the December 2012 Global Hazards page.
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Quayle, R.G., T.C. Peterson, A.N. Basist, and C. S. Godfrey, 1999: An operational near-real-time global temperature index. Geophys. Res. Lett., 26, 333-335.
Smith, T.M. and R.W. Reynolds, 2005: A global merged land air and sea surface temperature reconstruction based on historical observations (1880-1997), J. Clim., 18, 2021-2036.
Smith et al., 2008, Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006), J. Climate., 21, 2283-2293.