Climate Monitoring / Climate of 2007 / February / Global / Help

Climate of 2007 - February in Historical Perspective

Including Boreal Winter

National Climatic Data Center
15 March 2007

Global Analysis / Global Hazards / United States / U.S. Drought / Extremes
Use these links to access detailed analyses of Global and U.S. data.

Global Highlights:

Based on preliminary data, globally averaged combined land and sea surface temperature was the warmest on record for boreal winter (December 2006 - February 2007) and sixth warmest for February.
December 2006 - February 2007 temperatures were above average in Europe, Asia, western Africa, southeastern Brazil, and the northeast half of the United States. Cooler-than-average conditions occurred in parts of Saudi Arabia and central U.S.
Precipitation during December 2006 - February 2007 was above average in Scandinavia, England, northern Europe, southern Brazil, and the southern Plains to the eastern Great Lakes of the contiguous U.S. Drier than average conditions were observed in southern India, southern Europe, eastern and western U.S., and the eastern coast of Australia.
ENSO conditions transitioned to a neutral phase during February.

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 - February 2007 and February 2007 are shown on the dot maps below. The dot maps, 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 maps, below right, are 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 covered much of the globe during the first two months of the year. The January-February 2007 year-to-date map of temperature anomalies shows the presence of warmer than average temperatures across almost all land areas. Warmer than average Sea Surface Temperatures (SSTs) occured in the equatorial Pacific, North and South Atlantic, and the South Indian Ocean. Cooler than average conditions were observed in the northeastern Pacific and some areas in the South Pacific.

During boreal winter, temperatures were above average across the entire globe, with the exception of Saudi Arabia, Iraq, and areas in the central U.S. Warmer than average SSTs were observed across all oceans, with the exception of parts of the northeastern Pacific and South Pacific where cooler than average SSTs were observed.

Current season's Land Surface Temperature Dot map

larger image of Dec-Feb land surface temperature anomalies

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

larger image of Dec-Feb blended surface temperature anomalies

During February, there were above average temperatures across central and southern Europe, south Asia, most of Central America, parts of South America, and western sections of Africa, the U.S., and Alaska. Cooler than average temperatures were observed in Scandinavia, Siberia, and the northeastern half of the United States. Warmer than average SSTs occurred in the North and South Atlantic, Indian Ocean, and the Niño regions. SSTs decreased in the Niño regions during the month of February, transitioning from a warm phase to neutral ENSO conditions. Please see the latest ENSO discussion for additional information.

Current month's Land SurfaceTemperature Dot map

larger image of February land surface temperature anomalies

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

larger image of February blended surface temperature anomalies

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 2006 - February 2007 and the February 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 2007 at the weekly SST page.

Temperature Rankings and Graphics

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 global land and ocean surface temperatures were sixth warmest on record in February, but a record warm January helped push the Boreal winter to its highest values since records began in 1880. The global December 2006 - February 2007 land surface temperature was the warmest on record, while the ocean-surface temperature tied for second warmest in the 128-year period of record, approximately 0.06°C (0.1°F) cooler than the record established during the very strong El Niño episode of 1997-1998.

Current Month / Seasonal / Year-to-date

February	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+0.93°C (+1.67°F) +0.47°C (+0.85°F) +0.60°C (+1.08°F)	9th warmest 3rd warmest 6th warmest	2002 (+1.62°C/2.92°F) 1998 (+0.55°C/0.99°F) 1998 (+0.82°C/1.48°F)
Northern Hemisphere Land Ocean Land and Ocean	+1.08°C (+1.94°F) +0.47°C (+0.85°F) +0.70°C (+1.26°F)	10th warmest 2nd warmest 6th warmest	2002 (+2.11°C/3.80°F) 1998 (+0.53°C/0.95°F) 2002 (+1.03°C/1.85°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.49°C (+0.88°F) +0.49°C (+0.88°F) +0.49°C (+0.88°F)	13th warmest 4th warmest 5th warmest	1986 (+1.23°C/2.21°F) 1998 (+0.57°C/1.03°F) 1998 (+0.62°C/1.12°F)

larger image of global, land and ocean February temperatures

larger image of global and hemispheric February temperatures

December-February	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+1.35°C (+2.43°F) +0.48°C (+0.86°F) +0.72°C (+1.30°F)	warmest 2nd warmest warmest	2002 (+1.20°C/2.16°F) 1998 (+0.55°C/0.99°F) 2004 (+0.65°C/1.17°F)
Northern Hemisphere Land Ocean Land and Ocean	+1.59°C (+2.86°F) +0.50°C (+0.90°F) +0.91°C (+1.64°F)	warmest 2nd warmest warmest	2002 (+1.55°C/2.79°F) 1998 (+0.52°C/0.94°F) 2002 (+0.82°C/1.48°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.59°C (+1.06°F) +0.48°C (+0.86°F) +0.49°C (+0.88°F)	7th warmest 3rd warmest 4th warmest	1998 (+0.81°C/1.46°F) 1998 (+0.57°C/1.03°F) 1998 (+0.61°C/1.10°F)

larger image of global, land and ocean Dec-Feb temperatures

larger image of global and hemispheric Dec-Feb temperatures

January-February	Anomaly	Rank	Warmest Year on Record
Global Land Ocean Land and Ocean	+1.40°C (+2.52°F) +0.47°C (+0.85°F) +0.72°C (+1.30°F)	2nd warmest 3rd warmest 2nd warmest	2002 (+1.53°C/2.75°F) 1998 (+0.54°C/0.97°F) 2002 (+0.73°C/1.31°F)
Northern Hemisphere Land Ocean Land and Ocean	+1.67°C (+3.01°F) +0.48°C (+0.86°F) +0.93°C (+1.67°F)	2nd warmest 2nd warmest 2nd warmest	2002 (+1.99°C/3.58°F) 1998 (+0.52°C/0.94°F) 2002 (+0.98°C/1.76°F)
Southern Hemisphere Land Ocean Land and Ocean	+0.58°C (+1.04°F) +0.47°C (+0.85°F) +0.49°C (+0.88°F)	8th warmest 6th warmest 4th warmest	2003 (+0.81°C/1.46°F) 1998 (+0.56°C/1.01°F) 1998 (+0.60°C/1.08°F)

larger image of global, land and ocean year-to-date temperatures

larger image of global and hemispheric year-to-date temperatures

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 boreal winter, above average precipitation fell over areas that include Scandinavia, England, northern Europe, southern Brazil, and the southern Plains to the eastern Great Lakes of the contiguous U.S. Drier than average conditions were observed in southern India, southern Europe, eastern and western U.S., and the eastern coast of Australia.

During February 2007, above average precipitation fell over areas that include England, northern India, eastern Brazil, and parts of Europe. Below average precipitation was observed in eastern U.S., northwestern Brazil, and most of Australia. Additional details on flooding and drought can also be found on the February Global Hazards page.

Precipitation Dot map in Millimeters for December-February

larger image of Dec-Feb global land surface precipitation anomalies

Precipitation Dot map in Millimeters for February

larger imageof February global land surface precipitation anomalies

ENSO SST Analysis

Last week of the month's ENSO condtions Map

Click here for animated loop

Sea Surface Temperatures decreased across the equatorial Pacific Ocean during February, as the El Niño episode weakened to a neutral phase (shown in the adjacent animation of weekly sea surface temperature anomalies). A comprehensive summary of February 2007 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.

Northern Hemisphere Snow Cover Extent

As shown in the time series to the right, mean Northern Hemisphere snow cover extent during winter 2006/2007 was below average. Much of this was due to anomalously warm conditions across Asia, Europe, Canada, and the northeast half of the U.S. Winter 2006/2007 snow cover extent over the Northern Hemisphere was the 8th lowest extent in the historical record. Mean Northern Hemisphere winter snow cover extent for the 1967-2007 period of record is 45.4 million square kilometers.

larger image of Northern Hemisphere winter snow cover

Current season's North America Snow Cover extent

larger image of North America winter snow cover

Snow cover for winter 2006/2007 across North America was above average, and was the 13th largest extent over the 41-year historical record. This was in part due to a series of snow and ice storms that struck the U.S. during the month of February. Average North America winter snow cover extent is 17.0 million square kilometers for the 1967-2007 period of record.

As depicted in the time series to the right, Eurasia's snow cover extent this winter was the 3rd lowest on record behind 1975 and 1981. The near-record low extent was due in part to monthly mean temperatures above 5.0°C that covered much of Europe and Russia. Average Eurasian winter snow cover extent is 28.4 million square kilometers for the 1967-2007 period of record.

Current season's Eurasia Snow Cover extent

larger image of Eurasia winter snow cover

(Data were provided by Global Snow Laboratory, Rutgers University).

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Troposphere

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).

Lower Troposphere
Current Month / Seasonal / Year-to-date

February	Anomaly	Rank	Warmest Year on Record	Trend
UAH low-trop	+0.41°C/0.74°F	2nd warmest	1998 (+0.69°C/1.24°F)	+0.17°C/decade
*RSS low-trop	+0.33°C/0.59°F	8th warmest	1998 (+0.76°C/1.37°F)	+0.23°C/decade

*Version 03_0

December- February	Anomaly	Rank	Warmest Year on Record	Trend
UAH low-trop	+0.41°C/0.74°F	2nd warmest	1998 (+0.51°C/0.92°F)	+0.16°C/decade
*RSS low-trop	+0.39°C/0.70°F	5th warmest	1998 (+0.58°C/1.04°F)	+0.22°C/decade

*Version 03_0

January- February	Anomaly	Rank	Warmest Year on Record	Trend
UAH low-trop	+0.47°C/0.85°F	2nd warmest	1998 (+0.62°C/1.12°F)	+0.17°C/decade
*RSS low-trop	+0.40°C/0.72°F	7th warmest	1998 (+0.70°C/1.26°F)	+0.23°C/decade

*Version 03_0

Mid-Troposphere
Current Month / Seasonal / Year-to-date

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.

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 of year-to-date RATPAC mid-tropospheric temperatures

Larger Image of boreal winter RATPAC mid-tropospheric temperatures

Radiosonde measurements indicate that for the January-February year-to-date period, temperatures in the mid-troposphere were 0.68°C (1.22°F) above average; the 3rd warmest January-February since global measurements began in 1958, slightly cooler than January-February 1998 and the record warm January-February 2005. As shown in the table below, satellite measurements of the January-February 2007 year-to-date period for the middle troposphere varied from 2nd to 3rd warmest on record, depending on the analysis method.

During the boreal winter, radiosonde measurements indicate that temperatures in the mid-troposphere were 0.56°C (1.01°F) above average, the 4th warmest boreal winter on record. There is little difference between the 5 warmest boreal winter seasons on record for the globe (1998, 2004, 2005, 2007, 2006). The table below displays that satellite measurements for the boreal winter varied from 3rd to 5th warmest on record, depending on the analysis method.

The global mid-troposphere temperatures were warmer than average in February 2007, as shown in the table below. Satellite measurements for February 2007 varied from 5th to 7th warmest on record, depending on the analysis method.

February	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.20°C/0.36°F	5th warmest	1998 (+0.63°C/1.13°F)	+0.07°C/decade
*RSS mid-trop	+0.24°C/0.43°F	6th warmest	1998 (+0.71°C/1.28°F)	+0.14°C/decade
**UW-UAH mid-trop	+0.31°C/0.56°F	5th warmest	1998 (+0.80°C/1.44°F)	+0.15°C/decade
*UW-RSS mid-trop	+0.32°C/0.58°F	7th warmest	1998 (+0.83°C/1.49°F)	+0.20°C/decade

*Version 03_0

December- February	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.20°C/+0.36°F	4th warmest	1998 (+0.43°C/0.77°F)	+0.05°C/decade
*RSS mid-trop	+0.27°C/0.49°F	5th warmest	1998 (+0.49°C/0.88°F)	+0.12°C/decade
**UW-UAH mid-trop	+0.31°C/+0.56°F	3rd warmest	1998 (+0.57°C/1.03°F)	+0.12°C/decade
*UW-RSS mid-trop	+0.36°C/+0.65°F	5th warmest	1998 (+0.60°C/1.08°F)	+0.18°C/decade
RATPAC	+0.56°C/1.01°F	4th warmest	1998 (+0.59°C/1.06°F)	+0.16°C/decade

*Version 03_0

January- February	Anomaly	Rank	Warmest Year on Record	Trend
UAH mid-trop	+0.27°C/+0.49°F	2nd warmest	1998 (+0.56°C/1.01°F)	+0.07°C/decade
*RSS mid-trop	+0.34°C/0.61°F	3rd warmest	1998 (+0.62°C/1.12°F)	+0.13°C/decade
**UW-UAH mid-trop	+0.38°C/+0.68°F	2nd warmest	1998 (+0.71°C/1.28°F)	+0.14°C/decade
*UW-RSS mid-trop	+0.43°C/+0.77°F	3rd warmest	1998 (+0.75°C/1.35°F)	+0.20°C/decade
RATPAC	+0.68°C/1.22°F	3rd warmest	2005 (+0.75°C/1.35°F)	+0.15°C/decade

*Version 03_0

Stratosphere

Current Month / Seasonal

The table below summarizes stratospheric conditions for February 2007. 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 and the increase in greenhouse gases in the Earth's atmosphere. 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.

February	Anomaly	Rank	Coolest Year on Record
UAH stratosphere	-0.51°C (-0.92°F)	6th coolest	2006 (-0.79°C/-1.42°F)
*RSS stratosphere	-0.38°C (-0.68°F)	9th coolest	2006 (-0.70°C/-1.26°F)

*Version 03_0

December- February	Anomaly	Rank	Coolest Year on Record
UAH stratosphere	-0.57°C (-1.03°F)	8th coolest	2006 (-0.77°C/-1.39°F)
*RSS stratosphere	-0.43°C (-0.77°F)	9th coolest	2006 (-0.66°C/-1.19°F)

*Version 03_0

For additional details on precipitation and temperatures in February, 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.

For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:

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For questions about this report, please contact:

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