State of the Climate
Global Analysis
December 2006

National Oceanic and Atmospheric Administration

National Climatic Data Center

Use the form below to access monthly reports.

« November 2006
Global Analysis Report

Annual 2006 »
Global Analysis Report

Report:

Year: Month:

Global Highlights:

Based on preliminary data, globally averaged combined land and sea surface temperature was the warmest on record for December 2006 and fifth warmest for January-December.
December temperatures were above average in the United States, Europe, southern Asia, central Russia, and most of South America. Cooler-than-average conditions occurred in the Middle East Region.
Precipitation during December was above average in Scandinavia, England, Japan, central U.S., southeastern Africa, and most of South America. Drier than average conditions were observed in the eastern U.S., central Europe, eastern Australia and southern India.
ENSO conditions persisted in a warm phase (El Niño) during December.

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.

Introduction

Temperature anomalies for December 2006 are shown on the dot maps below. The dot map, below left, provide a spatial representation of anomalies calculated from the Global Historical Climatology Network (GHCN) data set of land surface stations using a 1961-1990 base period. The dot map, below right, is a product of a merged land surface and sea surface temperature anomaly analysis developed by Smith and Reynolds (2005). Temperature anomalies with respect to the 1961-1990 mean for land and ocean are analyzed separately and then merged to form the global analysis. Additional information on this product is available.

Anomalously warm temperatures have covered much of the globe throughout the year. The January-December 2006 map of temperature anomalies show the presence of warmer than average temperatures across all land areas except central Russia. Warmer than average SSTs occurred in all oceans with the expection of portions of the South Pacific and South Indian Oceans where cooler than average conditions were observed.

During December, there were above average temperatures across the U.S., Europe, southern Asia, central Russia, eastern South America, and western coast of Canada. Cooler than average temperatures were observed in the Middle East Region. Warmer than average SSTs occurred in the North Atlantic and the Niño regions. Temperatures in parts of these Niño regions were more than 1°C (1.80°F) above average, and the average temperature anomaly in the Niño 3.4 region increased in December to approximately 1.37°C (2.47°F). Please see the latest ENSO discussion for additional information on the developing El Niño event.

Current month's Land SurfaceTemperature Dot map

larger image

Current month's blended Land and sea surface Temperature Dot map

larger image

The mean position of upper level ridges of high pressure and troughs of low pressure (depicted by positive and negative 500-millibar height anomalies on the December map) are generally reflected by areas of positive and negative temperature anomalies at the surface, respectively. For other Global products see the Climate Monitoring Global Products page.

Images of sea surface temperature conditions are available for all weeks during 2006 at the weekly SST page.

Temperature Rankings and Graphics

Effective with the January, 2006 report, NCDC transitioned from the use of the Operational Global Surface Temperature Index (Quayle et al. 1999) to the blended land and ocean dataset developed by Smith and Reynolds (2005). The differences between the two methods are discussed in Smith et al. 2005.

December 2006 was the warmest December since global surface records began in 1880 for combined global land and ocean surface temperatures. December land surface temperatures were 4th warmest, while ocean surface temperatures were 2nd warmest in the 127-year record, behind 1997 during which the very strong 1997/1998 El Niño event was developing. The January - December 2006 land and ocean combined temperature is tied for 5th warmest on record.

Current Month / Year-to-date

December	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+1.29°C (+2.32°F) +0.51°C (+0.92°F) +0.72°C (+1.30°F)	4th warmest 2nd warmest 1st warmest	1939 (+1.34°C/2.41°F) 1997 (+0.56°C/1.01°F) 2003 (+0.70°C/1.26°F)
Northern Hemisphere Land Ocean Land and Ocean	+1.51°C (+2.72°F) +0.55°C (+0.99°F) +0.91°C (+1.64°F)	4th warmest 1st warmest 2nd warmest	1939 (+1.82°C/3.28°F) 2004 (+0.52°C/0.94°F) 2003 (+0.92°C/1.66°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.65°C (+1.17°F) +0.49°C (+0.88°F) +0.51°C (+0.92°F)	7th warmest 3rd warmest 3rd warmest	1997 (+0.80°C/1.44°F) 1997 (+0.60°C/1.08°F) 1997 (+0.63°C/1.13°F)

larger image

larger image

January-December	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+0.78°C (+1.40°F) +0.45°C (+0.81°F) +0.54°C (+0.97°F)	4th warmest 5th warmest 5th warmest	2005 (+0.97°C/1.75°F) 2003 (+0.48°C/0.86°F) 2005 (+0.61°C/1.10°F)
Northern Hemisphere Land Ocean Land and Ocean	+0.87°C (+1.57°F) +0.49°C (+0.88°F) +0.63°C (+1.13°F)	3rd warmest 4th warmest 2nd warmest	2005 (+1.02°C/1.84°F) 2005 (+0.54°C/0.97°F) 2005 (+0.72°C/1.30°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.54°C (+0.97°F) +0.43°C (+0.77°F) +0.44°C (+0.79°F)	6th warmest 5th warmest 6th warmest	2005 (+0.83°C/1.49°F) 1998 (+0.50°C/0.90°F) 1998 (+0.54°C/0.97°F)

larger image

The most current data may be accessed via the Global Surface Temperature Anomalies page.

This is a break in the document

Precipitation

The maps below represent anomaly values based on the GHCN data set of land surface stations using a base period of 1961-1990. During December 2006, above average precipitation fell over areas that include Scandinavia, Japan, central U.S., southeastern Africa, and most of South America. Below average precipitation was observed in eastern Australia, southcentral Europe, eastern U.S., eastern Brazil, and southern India. Additional details on flooding and drought can also be found on the December Global Hazards page.

larger image

Precipitation Dot map in Percent for December

larger image

ENSO SST Analysis

Last week of the month's ENSO condtions Map

Click here for animated loop

Sea Surface Temperatures continued to increase across the equatorial Pacific Ocean during December, indicative of a moderate El Niño episode (shown in the adjacent animation of weekly sea surface temperature anomalies). A comprehensive summary of December 2006 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 weeks since 2003 at the weekly SST page

Troposphere

Current Month / Year-to-date
Temperatures above the Earth's surface are measured using in-situ balloon-borne instruments (radiosondes) and polar-orbiting satellites (NOAA's TIROS-N). The radiosonde and the satellite records have been adjusted to remove time-dependent biases (artificialities caused by changes in radiosonde instruments and measurement practices as well as changes in satellite instruments and orbital features through time).

The radiosonde data used in this global analysis were developed using the Lanzante, Klein, Seidel (2003) ("LKS") bias-adjusted dataset and the First Difference Method (Free et al. 2004). Additional details are available. Satellite data have been adjusted by the Global Hydrology and Climate Center at the University of Alabama in Huntsville (UAH). An independent analysis is also performed by Remote Sensing Systems (RSS) and a third analysis has been performed by Dr. Qiang Fu of the the University of Washington (UW) (Fu et al. 2004)** to remove the influence of the stratosphere on the mid-troposphere value. Global averages from radiosonde data are available from 1958 to present, while satellite measurements began in 1979.

Larger Image

Radiosonde measurements indicate that for the January-December period, temperatures in the mid-troposphere (approximately 2 to 6 miles above the Earth's surface) were 0.56°C (1.01°F) above average; the 3rd warmest January-December since global measurements began in 1958. However, satellite measurements of the January-December 2006 period varied from 5th and 7th warmest on record, depending on the analysis method.

Although the rankings from satellite measurements are lower than the in-situ radiosonde measurements for 2006, the 1979-2006 trends from the radiosonde measurements (0.16°C/decade) are similar to those calculated from satellite observations, with the exception of the UAH version, as shown in the table below. The 1958-2006 mid-troposphere trend from radiosonde observations is 0.15°C/decade.

Note: These temperatures are for the atmospheric layer centered in the mid-troposphere (approximately 2-6 miles above the Earth's surface) which also includes a portion of the lower stratosphere. (The MSU channel used to measure mid-tropospheric temperatures receives about 25 percent of its signal above 6 miles). Because the stratosphere has cooled due to increasing greenhouse gases in the troposphere and losses of ozone in the stratosphere, the stratospheric contribution to the tropospheric average, as measured from satellites, may create an artificial component of cooling to the mid-troposphere temperatures. The University of Washington (UW) versions of the UAH and RSS analyses attempt to remove the stratospheric influence from the mid-troposphere measurements, and as a result the UW versions tend to have a larger warming trend than either the UAH or RSS versions. For additional information, please see NCDC's Microwave Sounding Unit page.

January- December	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.11°C/+0.20°F	7th warmest	1998 (+0.44°C/0.79°F)	+0.05°C/decade
*RSS mid-trop	+0.18°C/0.32°F	7th warmest	1998 (+0.52°C/0.94°F)	+0.13°C/decade
**UW-UAH mid-trop	+0.21°C/0.38°F	5th warmest	1998 (+0.57°C/1.03°F)	+0.12°C/decade
*UW-RSS mid-trop	+0.28°C/0.50°F	7th warmest	1998 (+0.63°C/1.13°F)	+0.19°C/decade
RATPAC	+0.56°C/1.01°F	3rd warmest	1998 (+0.74°C/1.33°F)	+0.16°C/decade

*Version 02_1

The December 2006 mid-troposphere rankings were also warmer than average as shown in the table below.

December	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.07°C/+0.13°F	12th warmest	1987 (+0.37°C/0.67°F)	+0.02°C/decade
*RSS mid-trop	+0.12°C/0.22°F	9th warmest	2003 (+0.38°C/0.64°F)	+0.09°C/decade
**UW-UAH mid-trop	+0.17°C/+0.31°F	8th warmest	1987 (+0.42°C/0.76°F)	+0.08°C/decade
*UW-RSS mid-trop	+0.20°C/+0.36°F	8th warmest	2003 (+0.48°C/0.86°F)	+0.15°C/decade

*Version 02_1

Stratosphere

Current Month
The table below summarizes stratospheric conditions for December 2006. On average, the stratosphere is located approximately between 10-14 miles above the Earth's surface. Over the last decade, stratospheric temperatures have been below average in part due to the depletion of ozone. The large positive anomaly in 1982 was caused by the volcanic eruption of El Chichon in Mexico, and the sharp jump in temperature in 1991 was a result of the eruption of Mt. Pinatubo in the Philippines. In both cases the temperatures returned to pre-eruption levels within two years.

December	Anomaly	Rank	Coolest Year on Record
UAH stratosphere	-0.68°C (-1.22°F)	4th coolest	2000 (-0.80°C/-1.44°F)
*RSS stratosphere	-0.58°C (-1.04°F)	4th coolest	2000 (-0.71°C/-1.28°F)

*Version 02_1

For additional details on precipitation and temperatures in December, see the Global Hazards page.

References

Christy, John R., R.W. Spencer, and W.D. Braswell, 2000: MSU Tropospheric Temperatures: Dataset Construction and Radiosonde Comparisons. J. of Atmos. and Oceanic Technology 17 1153-1170.

Free M., D.J. Seidel, J.K. Angell, J. Lanzante, I. Durre and T.C. Peterson (2005) Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new dataset of large-area anomaly time series, J. Geophys. Res., 10.1029/2005JD006169.

Free, M., J.K. Angell, I. Durre, J. Lanzante, T.C. Peterson and D.J. Seidel(2004), Using first differences to reduce inhomogeneity in radiosonde temperature datasets, J. Climate, 21, 4171-4179.

Fu, Q., C.M. Johanson, S.G. Warren, and D.J. Seidel, 2004: Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends. Nature, 429, 55-58.

Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003a), Temporal homogenization of monthly radiosonde temperature data. Part I: Methodology, J. Climate, 16, 224 240.

Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003b), Temporal homogenization of monthly radiosonde temperature data. Part II: Trends, sensitivities, and MSU comparison, J. Climate, 16, 241 262.
Mears, Carl A., M.C. Schabel, F.J. Wentz, 2003: A Reanalysis of the MSU Channel 2 Tropospheric Temperature Record. J. Clim 16, 3650-3664.

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

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.