State of the Climate
Global Analysis
October 2008

National Oceanic and Atmospheric Administration

National Climatic Data Center

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Based on preliminary data, the globally averaged combined land and sea surface temperature was the second warmest on record for October and ninth warmest on record for the January-October year-to-date period.
October 2008 temperatures were above average in Australia, Asia, western U.S., eastern Europe, northern Canada, eastern Brazil, and the southern countries of South America. Meanwhile, cooler-than-average conditions were present across the United Kingdom, Iceland, eastern and southern Alaska, southern and eastern continental U.S., and parts of western Europe.
Precipitation during October 2008 was variable in many areas. In general, precipitation was above average in Sri Lanka, southern India, central continental U.S., south-central and southeastern Russia, and across parts of the Caribbean, South America, and Europe. Drier-than-average conditions were observed across the Hawaiian Islands, Argentina, southern Chile, eastern Brazil, northwestern and eastern contiguous U.S., southeastern Australia, and across parts of Europe and southeastern Asia.
El Niño-Southern Oscillation (ENSO) conditions remained in a neutral phase 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 2008 are shown on the dot maps below. The dot map, below left, provides 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.

October's Land Surface Temperature Anomalies in degree Celsius

October's Land Surface Temperature
Anomalies in degrees Celsius

October's Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

During October, anomalous warm conditions were present over much of the world's land surface, especially across Asia, Australia, eastern Europe, eastern Brazil, and northern Canada, where temperatures were 2°-5°C (4°-9°F) above the 1961-1990 mean. Above average temperatures were also observed across the western contiguous U.S., northern and southern parts of Africa, and the southern countries of South America. These warm conditions brought the October 2008 global land surface anomalies to be the warmest since records began in 1880. Elsewhere, cooler-than-average conditions were present across the United Kingdom, Iceland, eastern and southern Alaska, southern and eastern continental U.S., and parts of western Europe.

Sea surface temperatures (SSTs) during October 2008 were warmer than average in the Atlantic, Indian, northwestern Pacific and eastern equatorial Pacific oceans. Cooler-than-average SSTs were present in parts of the southern oceans and in the central equatorial and northeastern Pacific Ocean. SST anomalies decreased in all Niño regions during October 2008, with the exception of the Niño 4 region, where SST anomalies slightly increased. Please see the October 2008 ENSO discussion for additional information.

Anomalously warm temperatures covered much of the world's land surface during January-October 2008. The year-to-date map shows the presence of warmer-than-average temperatures across all land areas, with the exception of parts of the northern continental U.S. and Colombia. Warmer-than-average SST conditions were present in the Atlantic and Indian oceans, eastern equatorial Pacific and parts of the northwest Pacific oceans. Cooler-than-average conditions were observed in the central equatorial Pacific, parts of the northeastern Pacific and some areas in the southern oceans.

The mean 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 October map, respectively) are generally reflected by areas of positive and negative temperature anomalies at the surface, respectively. For other Global products, please see the Climate Monitoring Global Products page.

Images of sea surface temperature conditions are available for all weeks during 2008 at the weekly SST page.

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Temperature Rankings and Graphics

Current Month / Year-to-date

Effective with the February 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). The ranks found in the tables below are based on records that began in 1880.

October 2008 ranked as the second warmest October since records began in 1880 for combined global land and ocean surface temperatures, behind 2003. Temperatures were warmer than average across Asia, Australia, Europe, and northern Canada, prompting the October 2008 global land surface anomalies to be the warmest on record. The global average ocean surface temperature (SST) in October was the sixth warmest on record.

October	Anomaly	Rank (out of 129 years)	Warmest (or Next Warmest) Year on Record
Global Land Ocean Land and Ocean	+1.12°C (+2.02°F) +0.45°C (+0.81°F) +0.63°C (+1.13°F)	warmest 6^th warmest 2^nd warmest	2005 (+1.08°C/1.94°F) 2003 (+0.55°C/0.99°F) 2003 (+0.69°C/1.24°F)
Northern Hemisphere Land Ocean Land and Ocean	+1.14°C (+2.05°F) +0.53°C (+0.95°F) +0.76°C (+1.37°F)	3^rd warmest 5^th warmest 3^rd warmest	2003 (+1.23°C/2.21°F) 2006 (+0.65°C/1.17°F) 2003 (+0.86°C/1.55°F)
Southern Hemisphere Land Ocean Land and Ocean	+1.06°C (+1.91°F) +0.39°C (+0.70°F) +0.49°C (+0.88°F)	2^nd warmest 5^th warmest 4^th warmest	2002 (+1.17°C/2.11°F) 1997 (+0.56°C/1.01°F) 1997 (+0.59°C/1.06°F)

October's Global Land and Ocean plot

October's Global Hemisphere plot

January-October	Anomaly	Rank (out of 129 years)	Warmest (or Next Warmest) Year on Record
Global Land Ocean Land and Ocean	+0.75°C (+1.35°F) +0.37°C (+0.67°F) +0.47°C (+0.85°F)	6^th warmest 10^th warmest 9^th warmest	2007 (+1.02°C/1.84°F) 1998 (+0.51°C/0.92°F) 2005 (+0.61°C/1.10°F)
Northern Hemisphere Land Ocean Land and Ocean	+0.83°C (+1.49°F) +0.40°C (+0.72°F) +0.56°C (+1.01°F)	5^th warmest 8^th warmest 8^th warmest	2007 (+1.17°C/2.11°F) 2005 (+0.55°C/0.99°F) 2007 (+0.71°C/1.28°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.50°C (+0.90°F) +0.34°C (+0.61°F) +0.37°C (+0.67°F)	8^th warmest 12^th warmest 10^th warmest	2005 (+0.85°C/1.53°F) 1998 (+0.52°C/0.94°F) 1998 (+0.56°C/1.01°F)

January-October Global Land and Ocean plot

January-October Global Hemisphere plot

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. Precipitation during October 2008 was above average over areas that include Sri Lanka, central continental U.S., southern India, south-central and southeastern Russia, and across parts of the Caribbean, South America, and Europe. Drier-than-average conditions were observed across the Hawaiian Islands, Argentina, southern Chile, eastern Brazil, northwestern and eastern U.S., southeastern Australia, and across parts of Europe and southeastern Asia.

October's Precipitation Anomalies in Millimeters

October Precipitation Percent Departures

October's Precipitation Percent Departures

According to the Australian Bureau of Meteorology (BoM), precipitation across Australia was 41 percent below normal during October, resulting in the twenty-fifth driest October on record. Exceptionally dry conditions were present across central and southeastern Australia. This resulted in South Australia having its driest October on record, Tasmania it's second driest, and Victoria its third driest October.

During October 2008, heavy rain produced by the Atlantic's sixteenth tropical depression resulted in widespread floods and landslides across parts of Central America. Storm-related fatalities were reported across the region. Northern Vietnam, was affected by heavy rain that triggered devastating floods. Fifty-four lives were claimed and over 100,000 homes were inundated. Tropical Cyclone Rashmi made landfall in the south-central coast of Bangladesh on October 27, dumping heavy rains that damaged thousands of homes and acres of crops.

Additional details on flooding and drought can also be found on the October Global Hazards page.

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ENSO SST Analysis

First week of October's ENSO condtions Map

Click here for animated loop

During October 2008, sea surface temperatures (SST) were slightly below average across the eastern and central equatorial Pacific Ocean, while slightly above average temperatures remained in the western equatorial Pacific Ocean. These conditions (shown in the adjacent animation of weekly sea surface temperature anomalies) are indicative of a neutral ENSO phase. A comprehensive summary of October 2008 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.

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Northern Hemisphere Snow Cover Extent

Northern Hemisphere Snow Cover Extent
for October 2008

As shown in the time series to the right, the mean Northern Hemisphere snow cover extent during October 2008 was below average. Much of this can be attributed to the above average temperatures across most of the Northern Hemisphere, where temperatures were 2-5°C (4°-9°F) in many places, leading to rapid snow melt. The Northern Hemisphere had the ninth least snow cover extent on record. The mean Northern Hemisphere October snow cover extent for the 1967-2008 period of record was 18.3 million square kilometers.

North America Snow Cover Extent
for October 2008

Across North America, snow cover for October 2008 was below average, the 16^th least extent since satellite records began in 1967. The mean North America October snow cover extent was 8.12 million square kilometers for the 1967-2008 period of record. Significant winter storms brought heavy snow across parts of the U.S. During October 10-12, a winter storm dumped heavy accumulations of snow across the western states. The storm dumped as much as 83.8 cm (33 inches) of snow across parts of Wyoming. While in Montana, the city of Red Lodge recorded its highest snowfall total in a period of 24-hours when 107 cm (42 inches) of snow fell.

Eurasia Snow Cover
Extent for October 2008

As depicted in the time series to the right, Eurasia's snow cover extent during October 2008 was below average. This was the 11th least snow cover extent over the 41-year historical period. Much of this can be attributed to the above normal temperatures that covered most of the Asian continent. On average, the Eurasian snow cover extent in October was 10.2 million square kilometers for the 1967-2008 period of record.

Data were provided by the Global Snow Laboratory, Rutgers University.

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Sea Ice Extent

October's Northern Hemisphere
Sea Ice Extent plot

According to the National Snow and Ice Data Center, the October 2008 Northern Hemisphere sea ice extent, which is measured from passive microwave instruments onboard NOAA satellites, was the third least October sea ice extent on record, behind 2007 and 2006. Average ice extent during October 2008 was 8.4 million square kilometers, which is 9.5 percent below the 1979-2000 average. Sea ice extent for October has decreased at a rate of 5.4 percent per decade, since satellite records began in 1979.

October's Southern Hemisphere
Sea Ice Extent plot

Meanwhile, the October 2008 Southern Hemisphere sea ice extent was slightly below the 1979-2000 mean. This was the eighth least sea ice extent in October (1.02 percent below the 1979-2000 mean) over the 30-year historical period. Sea ice extent for October has increased at a rate of 0.7 percent per decade.

For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page, provided by the NOAA's National Snow and Ice Data center (NSIDC).

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Troposphere

Temperatures above the Earth's surface are measured within the lower troposphere, middle troposphere, and stratosphere using in-situ balloon-borne instruments (radiosondes) and polar-orbiting satellites (NOAA's TIROS-N). The radiosonde and 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). Global averages from radiosonde data are available from 1958 to present, while satellite measurements began in 1979.

Lower Troposphere

Current Month / Year-to-date

These temperatures are for the lowest 8 km (5 miles) of the atmosphere. Information on the UAH and RSS sources of troposphere data is available.

October	Anomaly	Rank (out of 30 years)	Warmest (or Next Warmest) Year on Record	Trend
UAH low-trop	+0.16°C/+0.29°F	10^th warmest	2005 (+0.39°C/0.70°F)	+0.14°C/decade
*RSS low-trop	+0.18°C/+0.33°F	10^th warmest	2003 (+0.46°C/0.84°F)	+0.17°C/decade

*Version 03_0

January- October	Anomaly	Rank (out of 30 years)	Warmest [Coolest] (or Next Warmest [Coolest]) Year on Record	Trend
UAH low-trop	+0.02°C/+0.04°F	19^th warmest	1998 (+0.57°C/+1.03°F)	+0.12°C/decade
*RSS low-trop	+0.07°C/+0.13°F	16^th warmest	1998 (+0.61°C/+1.10°F)	+0.16°C/decade

*Version 03_0

Mid-troposphere

Current Month / Year-to-date

These temperatures are for the atmospheric layer centered in the mid-troposphere (approximately 3-10 km (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 10 km (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.

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) (RATPAC). 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 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.

RATPAC January-October plot

Radiosonde measurements indicate that for the January-October year-to-date period, temperatures in the mid-troposphere were 0.17°C (0.31°F) above average, resulting in the 19^th warmest January-October since global measurements began in 1958. However, as shown in the table below, satellite measurement of the January-October year-to-date period for the middle troposphere varied from sixth coolest (25^th warmest) to eleventh coolest (20^th warmest) on record.

The global mid-troposphere temperatures were near to slightly above average in October 2008. As shown in the table below, satellite measurement for October 2008 ranked from 14^th warmest to 20^th warmest on record.

October	Anomaly	Rank (out of 30 years)	Warmest [Coolest] (or Next Warmest [Coolest]) Year on Record	Trend
UAH mid-trop	-0.02°C/-0.04°F	20^th warmest	1998 (+0.35°C/+0.63°F)	+0.07°C/decade
*RSS mid-trop	+0.01°C/+0.01°F	20^th warmest	1998 (+0.41°C/+0.75°F)	+0.11°C/decade
**UW-UAH mid-trop	+0.08°C/+0.15°F	14^th warmest	1998 (+0.52°C/+0.93°F)	+0.14°C/decade
*UW-RSS mid-trop	+0.11°C/+0.19°F	14^th warmest	1998 (+0.57°C/+1.02°F)	+0.18°C/decade

*Version 03_0

January- October	Anomaly	Rank (out of 30 years)	Warmest [Coolest] (or Next Warmest [Coolest]) Year on Record	Trend
UAH mid-trop	-0.13°C/-0.23°F	25^th warmest (6^th coolest)	1998 (+0.52°C/+0.94°F) [1989 & 1993 (-0.21°C/-0.38°F)]	+0.05°C/decade
*RSS mid-trop	-0.07°C/-0.13°F	22^nd warmest (9^th coolest)	1998 (+0.56°C/+1.01°F) [1985 (-0.23°C/-0.41°F)]	+0.10°C/decade
**UW-UAH mid-trop	-0.03°C/-0.05°F	21^st warmest (10^th coolest)	1998 (+0.66°C/+1.19°F) [1984 (-0.24°C/-0.43°F)]	+0.11°C/decade
*UW-RSS mid-trop	+0.02°C/0.04°F	20^th warmest (11^th coolest)	1998 (+0.69°C/+1.24°F) [1985 (-0.23°C/-0.41°F)]	+0.16°C/decade
RATPAC	+0.17°C/+0.31°F	19^th warmest (out of 51 years)	1998 (+0.79°C/+1.42°F)	+0.15°C/decade

*Version 03_0

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Stratosphere

Current Month

The table below summarizes stratospheric conditions for October 2008. On average, the stratosphere is located approximately 16-23 km (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.

October	Anomaly	Rank (out of 30 years)	Coolest Year on Record
UAH stratosphere	-0.65°C (-1.17°F)	4^th coolest	2000 (-0.81°C/-1.46°F)
*RSS stratosphere	-0.69°C (-1.24°F)	3^rd coolest	2000 (-0.79°C/-1.42°F)

*Version 03_0

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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.

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