State of the Climate
Global Analysis
October 2006

National Oceanic and Atmospheric Administration

National Climatic Data Center

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Global Highlights:

Based on preliminary data, globally averaged combined land and sea surface temperature was fourth warmest on record for October 2006, fifth warmest for January-October year-to-date.
October temperatures were above average in Alaska, Europe and most of south Asia. Cooler-than-average conditions occurred in Siberia and the majority of the U.S.
Precipitation during October was above average in most of the eastern U.S., southern parts of South America, Scandinavia, and Thailand. Drier than average conditions were observed in eastern Asia, Australia and the west coast of Canada.
ENSO conditions remained in a warm phase (El Niño) during October.

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 October 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.

During October, there were above average temperatures across Alaska, Europe, Southeast Asia, eastern parts of Africa and Brazil. Cooler than average temperatures were observed in Siberia and the majority of the U.S. Warmer than average SSTs occurred in the North Atlantic and the Niño 3 and 1+2 regions. Temperatures in parts of these Niño regions were more than 2°C above average, and the average temperature in the Niño 3.4 region increased markedly in October to approximately 1°C. Please see the latest ENSO discussion for additional information on the developing El Niño event.

Anomalously warm temperatures have covered much of the globe throughout the year. The January-October 2006 year-to-date map of temperature anomalies show the presence of warmer than average temperatures across all land areas except central Russia and western Australia. Warmer than average SSTs occurred in the South Pacific, North and South Atlantic and the South Indian Ocean, with cooler than average conditions observed off the coast of southern Australia.

Current month's Land SurfaceTemperature Dot map

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

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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 October 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.

October 2006 was the 4th warmest October since global surface records began in 1880 for global land and ocean surface temperatures. October land surface temperatures were 3rd warmest, while ocean surface temperatures were 4th warmest in the 127-year record. The January-October 2006 land and ocean combined temperature was tied for 5th warmest on record.

Current Month / Year-to-date

October	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+0.80°C (+1.44°F) +0.48°C (+0.86°F) +0.57°C (+1.03°F)	3rd warmest 4th warmest 4th warmest	2005 (+1.07°C/1.93°F) 2003 (+0.55°C/0.99°F) 2003 (+0.69°C/1.24°F)
Northern Hemisphere Land Ocean Land and Ocean	+0.84°C (+1.51°F) +0.64°C (+1.15°F) +0.72°C (+1.30°F)	3rd warmest 2nd warmest 3rd warmest	2003 (+1.22°C/2.20°F) 2003 (+0.65°C/1.17°F) 2003 (+0.86°C/1.55°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.67°C (+1.21°F) +0.36°C (+0.65°F) +0.40°C (+0.72°F)	10th warmest 9th warmest 9th warmest	1988 (+1.47°C/2.65°F) 1997 (+0.56°C/1.01°F) 1997 (+0.59°C/1.06°F)

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January-October	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+0.74°C (+1.33°F) +0.44°C (+0.79°F) +0.52°C (+0.94°F)	4th warmest 6th warmest 5th warmest	2005 (+0.95°C/1.71°F) 1998 (+0.51°C/0.92°F) 2005 (+0.61°C/1.10°F)
Northern Hemisphere Land Ocean Land and Ocean	+0.81°C (+1.46°F) +0.47°C (+0.85°F) +0.60°C (+1.08°F)	4th warmest 5th warmest 5th warmest	2002 (+1.00°C/1.80°F) 2005 (+0.55°C/0.99°F) 2005 (+0.71°C/1.28°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.50°C (+0.90°F) +0.42°C (+0.76°F) +0.43°C (+0.77°F)	7th warmest 5th warmest 5th warmest	2005 (+0.86°C/1.55°F) 1998 (+0.52°C/0.94°F) 1998 (+0.56°C/1.01°F)

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

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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 October, above average precipitation fell over areas that include much of the eastern contiguous U.S. including the Mississippi Valley, western Alaska, Scandinavia, southern parts of South America, Portugal, Turkey and Thailand. Heavy rain and flooding occurred in Ethiopia, southern Alaska, and Turkey. Below average precipitation was observed in the western coast of Canada, southern Europe, eastern Australia and much of eastern Asia. Additional details on flooding and drought can also be found on the October Global Hazards page.

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Precipitation Dot map in Percent for October

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ENSO SST Analysis

Last week of the month's ENSO condtions Map

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Sea Surface Temperatures continued to increase across the central and eastern equatorial Pacific Ocean during October, indicative of a strengthening El Niño episode (shown in the adjacent animation of weekly sea surface temperature anomalies). A comprehensive summary of October 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 during 2006 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.

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Radiosonde measurements indicate that for the January-October year-to-date period, temperatures in the mid-troposphere (approximately 2 to 6 miles above the Earth's surface) were 0.67°C above average being the 2nd warmest January-October since global measurements began in 1958. However, satellite measurements of the January-October 2006 year-to-date period varied from 6th warmest to 11th warmest on record depending on the analysis method.

Although the rankings from satellite measurements are lower than the in-situ radiosonde measurements for 2006 year-to-date, with the exception of the UAH version, the 1979-2006 trends from the radiosonde measurements (0.16°C/decade) are similar to those calculated from satellite observations (0.12°C to 0.19°C/decade), 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- October	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.07°C/0.13°F	11th warmest	1998 (+0.52°C/0.94°F)	+0.06°C/decade
*RSS mid-trop	+0.19°C/0.34°F	7th warmest	1998 (+0.58°C/1.04°F)	+0.14°C/decade
**UW-UAH mid-trop	+0.18°C/0.32°F	6th warmest	1998 (+0.65°C/1.17°F)	+0.12°C/decade
*UW-RSS mid-trop	+0.29°C/0.52°F	6th warmest	1998 (+0.70°C/1.26°F)	+0.19°C/decade
RATPAC	+0.67°C/1.21°F	2nd warmest	1998 (+0.78°C/1.40°F)	+0.16°C/decade

*Version 02_1

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

October	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.15°C/0.27°F	9th warmest	1998 (+0.36°C/0.65°F)	+0.09°C/decade
*RSS mid-trop	+0.32°C/0.58°F	4th warmest	1998 (+0.45°C/0.81°F)	+0.17°C/decade
**UW-UAH mid-trop	+0.27°C/0.49°F	5th warmest	1998 (+0.51°C/0.92°F)	+0.16°C/decade
*UW-RSS mid-trop	+0.46°C/0.83°F	4th warmest	1998 (+0.59°C/1.06°F)	+0.24°C/decade

*Version 02_1

Stratosphere

Current Month
The table below summarizes stratospheric conditions for October 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. Temperatures returned to pre-eruption levels within two years.

October	Anomaly	Rank	Coolest Year on Record
UAH stratosphere	-0.61°C (-1.10°F)	4th coolest	2000 (-0.79°C/-1.42°F)
*RSS stratosphere	-0.68°C (-1.22°F)	3rd coolest	2005 (-0.72°C/-1.40°F)

*Version 02_1

For additional details on precipitation and temperatures in October, 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.