Global Analysis - September 2009
Contents of this Section:
- The combined global land and ocean surface temperature for September 2009 was 0.62°C (1.12°F) above the 20th Century average of 15.0°C (59.0°F). This was the second warmest September on record, behind 2005, and the 33rd consecutive September with a global temperature above the 20th Century average. The last below-average September occurred in 1976.
- The global land surface temperature for September 2009 was 0.97°C (1.75°F) above the 20th Century average of 12.0°C (53.6°F), and ranked as the second warmest September on record, also behind 2005.
- The worldwide ocean temperature tied with 2004 as the fifth warmest September on record, 0.50°C (0.90°F) above the 20th Century average of 16.2°C (61.1°F). Warmer-than-average sea surface temperatures were widespread, particularly in lower latitudes. The near-Antarctic southern ocean and the Gulf of Alaska featured notable cooler-than-average temperatures.
- For the year to date, the global combined land and ocean surface temperature of 14.7°C (58.5°F) was the sixth-warmest January-through-September period on record. This value is 0.55°C (0.99°F) above the 20th Century average.
- A weak El Niño persisted across the equatorial Pacific Ocean during September. Sea surface temperature observations in the equatorial Pacific Ocean during the month remained above average. According to NOAA's Climate Prediction Center, El Niño is expected to strengthen and last through the Northern Hemisphere winter of 2009-2010.
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.
Temperature Rankings and Graphics
(out of 130 years)
|Warmest on Record|
|Land and Ocean||+0.62||+1.12||2nd warmest||2005||+0.66||+1.19|
|Land and Ocean||+0.71||+1.28||2nd warmest||2005||+0.83||+1.49|
|Land and Ocean||+0.53||+0.95||2nd warmest*||1997||+0.65||+1.17|
*Signifies a tie
(out of 130 years)
|Warmest on Record|
|Land and Ocean||+0.55||+0.99||6th warmest||1998||+0.65||+1.17|
|Land and Ocean||+0.61||+1.10||5th warmest||2007||+0.72||+1.30|
|Land and Ocean||+0.51||+0.92||5th warmest||1998||+0.62||+1.12|
*Signifies a tie
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.
ENSO SST Analysis
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.
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.
Smith, et al (2008), Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006), J. Climate., 21, 2283-2293.