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Please Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective with the July 2009 State of the Climate Report, NCDC transitioned to the new version (version 3b) of the extended reconstructed sea surface temperature (ERSST) dataset. ERSST.v3b is an improved extended SST reconstruction over version 2. For more information about the differences between ERSST.v3b and ERSST.v2 and to access the most current data, please visit NCDC's Global Surface Temperature Anomalies page.
Temperature anomalies for September 2009 are shown on the dot maps below. The dot map on the left provides a spatial representation of anomalies calculated from the Global Historical Climatology Network (GHCN) dataset of land surface stations using a 1961-1990 base period. The dot map on the right is a product of a merged land surface and sea surface temperature (SST) anomaly analysis developed by Smith et al. (2008). Temperature anomalies with respect to the 1961-1990 average 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 combined global land and ocean surface temperatures for September 2009 ranked as the second warmest September on record since records began in 1880. The combined global land and ocean temperature anomaly was 0.62°C (1.12°F), falling only 0.04°C (0.07°F) short of tying the record set in 2005. Similar to the combined global land and ocean temperatures, the worldwide land surface temperature was the second warmest September on record, behind 2005, with a temperature anomaly of 0.97°C (1.75°F) above the 20th Century average. During the month of September, warmer-than-average temperatures were present across Canada, Europe, the northern and western contiguous U.S., eastern Brazil, and most of Asia and Australia. The warmest anomalies occurred in Canada, the northern and western contiguous U.S., western Russia, and parts of Australia, where temperature anomalies ranged from 3-5°C (5-9°F) above the 1961-1990 average.
Separately, the Northern Hemisphere and the Southern Hemisphere experienced above average temperatures for the combined land and ocean areas, resulting in the second warmest September on record, behind 2005 and 1997, respectively. The Southern Hemisphere September temperature tied with 2003.
For the contiguous U.S., the national average during September 2009 was 19.1°C (66.4°F), 0.6°C (1°F) above the 20th Century average and the 32nd warmest on record. The West region and the states that constitute the region had their warmest September on record. Please see the United States September 2009 National Overview for additional information.
The worldwide sea surface temperatures (SST) during September 2009 were warmer than average, but not record-breaking as the June-August seasonal temperature. The global ocean temperature tied with 2004 as the fifth warmest September on record, with an anomaly of 0.50°C (0.90°F) above the 20th Century average. SST were warmer than average across much of the world's oceans, with the exception of cooler-than-average conditions across parts of the northern Atlantic, near-Antarctic southern oceans, and the Gulf of Alaska. A weak El Niño persisted across the equatorial Pacific Ocean during September 2009. Sea surface temperature anomalies across the equatorial Pacific Ocean were between 0.3-0.8°C (0.5-1.4°F) above average during the month. The Niño regions 1+2 and 3 SST were cooler when compared with August 2009; however, remained above average. Meanhwile, the Niño regions 3.4 and 4 remained nearly unchanged during September 2009. El Niño is expected to strengthen and last through the Northern Hemisphere winter 2009-2010, according to NOAA's Climate Prediction Center (CPC). Please see the September 2009 ENSO discussion for additional information.
The January-September 2009 map of temperature anomalies shows the presence of warmer-than-average conditions across much of the globe's surface area, with the exception of cooler-than-average conditions across parts of Canada, the northern contiguous United States, the southern oceans, and along the eastern North Pacific Ocean. The combined global land and ocean surface temperature for the year-to-date period ranked as the sixth warmest January-September period on record. This value is 0.55°C (0.99°F) above the 20th Century average.
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 September 2009 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 2009 from the weekly SST page.
| September | Anomaly | Rank (out of 130 years) |
Warmest Year on Record |
|---|---|---|---|
| Global | |||
| Land | +0.97°C (+1.75°F) | 2nd warmest | 2005 (+1.01°C/1.82°F) |
| Ocean | +0.50°C (+0.90°F) | 5th warmest | 2003 (+0.57°C/1.03°F) |
| Land and Ocean | +0.62°C (+1.12°F) | 2nd warmest | 2005 (+0.66°C/1.19°F) |
| Northern Hemisphere | |||
| Land | +1.04°C (+1.87°F) | 2nd warmest | 2005 (+1.18°C/2.12°F) |
| Ocean | +0.53°C (+0.95°F) | 6th warmest | 2003 (+0.65°C/1.17°F) |
| Land and Ocean | +0.71°C (+1.28°F) | 2nd warmest | 2005 (+0.83°C/1.49°F) |
| Southern Hemisphere | |||
| Land | +0.78°C (+1.40°F) | 5th warmest | 2007 (+1.04°C/1.87°F) |
| Ocean | +0.49°C (+0.88°F) | 4th warmest | 1997 (+0.58°C/1.04°F) |
| Land and Ocean | +0.53°C (+0.95°F) | 2nd warmest | 1997 (+0.65°C/1.17°F) |
| January - September | Anomaly | Rank (out of 130 years) |
Warmest Year on Record |
|---|---|---|---|
| Global | |||
| Land | +0.80°C (+1.44°F) | 5th warmest | 2007 (+1.00°C/1.80°F) |
| Ocean | +0.47°C (+0.85°F) | 6th warmest | 1998 (+0.55°C/0.99°F) |
| Land and Ocean | +0.55°C (+0.99°F) | 6th warmest | 1998 (+0.65°C/1.17°F) |
| Northern Hemisphere | |||
| Land | +0.85°C (+1.53°F) | 6th warmest | 2007 (+1.17°C/2.11°F) |
| Ocean | +0.46°C (+0.83°F) | 5th warmest | 2005 (+0.55°C/0.99°F) |
| Land and Ocean | +0.61°C (+1.10°F) | 5th warmest | 2007 (+0.72°C/1.30°F) |
| Southern Hemisphere | |||
| Land | +0.69°C (+1.24°F) | 3rd warmest | 2005 (+0.83°C/1.49°F) |
| Ocean | +0.49°C (+0.88°F) | 4th warmest | 1998 (+0.58°C/1.04°F) |
| Land and Ocean | +0.51°C (+0.92°F) | 5th warmest | 1998 (+0.62°C/1.12°F) |
The most current data may be accessed via the Global Surface Temperature Anomalies page.
The maps below represent anomaly values based on the GHCN dataset of land surface stations using a base period of 1961-1990. The areas with the wettest anomalies during September 2009 included the southeastern and south central contiguous U.S., southern Brazil, and parts of India, Scandinavia, the Philippines, and northwestern Africa. The driest anomalies during September 2009 were observed across eastern Asia.
Typhoon Ketsana became, so far, 2009's second deadliest tropical cyclone, claiming nearly 500 lives across the Philippines, Cambodia, Laos and Vietnam. The storm struck the Philippines on September 26th, lashing the islands with strong winds and torrential rains. Approximately 80 percent of Manila was submerged during its worst flooding in 40 years. The heaviest precipitation fell in a short time: 424 mm (16.7 inches) in a 12-hour period, with 340 mm (13.4 inches) in a six-hour period. Each value exceeded the existing 24-hour record (335 mm or 13.2 inches) set in 1967, as well as the average September monthly rainfall (391 mm or 15.4 inches).
Other notable precipitation extremes during September 2009 included the rainfall deficit across India. According to India's Meteorological Department, the country as a whole experienced 23 percent below its long term average for the monsoon season (June 1 - September 30), resulting in the most precipitation-deficient such season since 1972.
Additional details on flooding and drought can also be found on the September 2009 Global Hazards page.
Sea surface temperatures remained above average across the equatorial Pacific Ocean during September 2009, with SST anomalies ranging from 0.3-0.8°C (0.5-1.4°F) above average. The July-September Oceanic Niño Index was +0.8°C (1.4°F), which is above the NOAA El Niño threshold of +0.5°C (+0.9°F). These conditions are indicative of a weak El Niño. A comprehensive summary of September 2009 ENSO conditions can be found on the ENSO monitoring page. For the latest advisory on ENSO conditions, please visit NOAA's Climate Prediction Center (CPC) and the CPC ENSO Diagnostic Discussion.
Images of weekly sea surface temperature conditions are available at the weekly SST page.
According to the National Snow and Ice Data Center (NSIDC), the September 2009 Northern Hemisphere sea ice extent—which is measured from passive microwave instruments onboard NOAA satellites—was 5.4 million square kilometers (23.8 percent or 1.7 million square kilometers below the 1979–2000 average), resulting in the third lowest September sea ice extent on record, behind 2007 and 2008. When compared to September 2007—the record low—2009 was 1.1 million square kilometers above the record low and 690,000 square kilometers greater than September 2008, the second-lowest extent. This was the 13th consecutive September with sea ice extent below average and the past five years have seen the lowest sea ice extents on record. September 1996 was the last year that had above-average sea ice extent. September Arctic sea ice extent has decreased at an average rate of 11.2 percent per decade since 1979. The lowest Northern Hemisphere sea ice extent occurs in September each year.
Conversely, the September 2009 Southern Hemisphere sea ice extent was 2.2 percent above the 1979–2000 average. This was the third largest sea ice extent in September, behind 2006 and 2007. Southern Hemisphere sea ice extent for September has increased at an average 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 NOAA's National Snow and Ice Data Center (NSIDC).
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 date back to 1979.
These temperatures are for the lowest 8 km (5 miles) of the atmosphere. Information on the University of Alabama in Huntsville (UAH) and Remote Sensing Systems (RSS) sources of troposphere data is available.
| September | Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | +0.42°C/+0.76°F | 2nd warmest | 1998 (+0.43°C/+0.77°F) | +0.13°C/decade |
| *RSS low-trop | +0.48°C/+0.86°F | 2nd warmest | 1998 (+0.49°C/+0.89°F) | +0.18°C/decade |
*Version 03_0
| January- September |
Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | +0.23°C/+0.41°F | 7th warmest | 1998 (+0.59°C/+1.06°F) | +0.12°C/decade |
| *RSS low-trop | +0.25°C/+0.45°F | 7th warmest | 1998 (+0.63°C/+1.13°F) | +0.16°C/decade |
*Version 03_2
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 Microwave Sounding Unit [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.
Radiosonde measurements indicate that, for the January-September year-to-date period, temperatures in the mid-troposphere were 0.47°C (0.84°F) above average, resulting in the seventh warmest January-September (out of 52 years) since global radiosonde measurements began in 1958. This was the 17th consecutive January-September period with temperature anomalies warmer than average. Meanwhile, satellite analyses of the January-September year-to-date period for the middle troposphere varied from 9th to 12th warmest in the 31-year satellite record.
The global mid-troposphere temperatures were above average during September 2009. As shown in the table below, satellite measurements for September 2009 ranked second warmest to third warmest on record.
| September | Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | +0.30°C/+0.54°F | 2nd warmest | 1998 (+0.43°C/+0.77°F) | +0.08°C/decade |
| *RSS mid-trop | +0.35°C/+0.64°F | 3rd warmest | 1998 (+0.49°C/+0.89°F) | +0.14°C/decade |
| UW-UAH mid-trop | +0.41°C/+0.73°F | 2nd warmest | 1998 (+0.60°C/+1.07°F) | +0.15°C/decade |
| UW-*RSS mid-trop | +0.45°C/+0.81°F | 3rd warmest | 1998 (+0.64°C/+1.15°F) | +0.20°C/decade |
*Version 03_2
| January- September |
Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | +0.07°C/+0.13°F | 12th warmest | 1998 (+0.54°C/+0.97°F) | +0.04°C/decade |
| *RSS mid-trop | +0.12°C/+0.22°F | 12th warmest | 1998 (+0.58°C/+1.04°F) | +0.09°C/decade |
| UW-UAH mid-trop | +0.17°C/+0.31°F | 7th warmest | 1998 (+0.67°C/+1.21°F) | +0.10°C/decade |
| UW-*RSS mid-trop | +0.20°C/+0.36°F | 9th warmest | 1998 (+0.70°C/+1.26°F) | +0.15°C/decade |
| RATPAC** | +0.47°C/+0.84°F | 7th warmest | 1998 (+0.80°C/+1.44°F) | +0.15°C/decade |
*Version 03_2
**RATPAC's rank is based on records that began in 1958 (52 years).
The table below summarizes stratospheric conditions for September 2009. 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.
| September | Anomaly | Rank (out of 31 years) |
Coolest Year on Record |
|---|---|---|---|
| UAH stratosphere | -0.46°C (-0.83°F) | 11th coolest | 1996 (-0.80°C/-1.44°F) |
| *RSS stratosphere | -0.41°C (-0.74°F) | 10th coolest | 1996 (-0.73°C/-1.31°F) |
*Version 03_2
For additional details on precipitation and temperatures in September, see the Global Hazards page.
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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