Global Analysis - July 2009
Contents of this Section:
- The combined global land and ocean surface temperature for July 2009 was the fifth warmest on record, at 0.57°C (1.03°F) above the 20th century average of 15.8°C (60.4°F).
- July 2009 was the 33rd consecutive July with an average global land and ocean surface temperature above the 20th century average. The last July with global temperatures below the 20th century average occurred in 1976.
- The global ocean surface temperature for July 2009 was the warmest on record, 0.59°C (1.06°F) above the 20th century average of 16.4°C (61.5°F). This broke the previous July record set in 1998. The July ocean surface temperature departure from the long-term average equals June 2009 value, which was also a record.
- The global land surface temperature for July 2009 was 0.51°C (0.92°F) above the 20th century average of 14.3°C (57.8°F), and tied with 2003 as the ninth-warmest July on record.
- For the year to date, the global combined land and ocean surface temperature of 14.3°C (57.9°F) tied with 2004 for the sixth-warmest January-through-July period on record.
- El Niño persisted across the equatorial Pacific Ocean during July 2009. Related sea-surface temperature (SST) anomalies increased for the sixth consecutive month in this ENSO domain, where July SSTs were more than 0.5°C (0.9°F) above average. If El Niño conditions continue to mature, as now projected by NOAA, global temperatures are likely to exceed previous record highs.
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.
Please Note: 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. Most of the improvements are justified by testing with simulated data. The primary difference in version 3b, compared to version 2, is improved low-frequency tuning that increases the sensitivity to data prior to 1930. In ERSST v3b, satellite data was removed from the ERSST product. The addition of satellite data from 1985 to present caused problems for many users. Although the satellite data were corrected with respect to the in situ data, a small residual cold bias remained at high southern latitudes where in situ data were sparse. For more information about the differences between ERSST.v3b and ERSST.v2 please read Summary of Recent Changes in the Land-Ocean Temperature Analyses and Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006) paper.
Temperature anomalies for July 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.
The combined global land and ocean surface temperatures for July 2009 ranked as the fifth warmest on record in July since records began in 1880. However, the global land surface temperatures for July 2009 tied with 2003 as the ninth warmest July on record. Warmer-than-average temperatures were present across all land areas with the exception of cooler-than-average conditions across parts of eastern and western Asia, most of southern South America, central Canada, and the eastern half of the contiguous United States. The most notable cooler-than-average temperatures were recorded across the contiguous U.S. and central Canada. For the contiguous U.S., the average July temperature of 23.1°C (73.5°F) was the coolest since 1994. Please see the United States July 2009 National Overview for additional information.
According to Environment Canada, temperatures across Ontario were well below average, with an overall anomaly of 2.2°C (4.0°F) below average. Several locations experienced their lowest temperatures since 1992, and three locations set new low mean temperatures. Pickle Lake set a new monthly low mean temperature for the month of July as temperatures dropped to 14.4°C (57.9°F), surpassing the previous record of 14.5°C (58.1°F) set in 1965. Ridgetown and Elliot Lake also broke their monthly low mean temperatures which were first set in 1891 and 1996, respectively.
The global ocean SST for July 2009 was the warmest on record for the second consecutive month, 0.59°C (1.06°F) above the 20th century average of 16.4°C (61.5°F). This broke the previous July record set in 1998. Sea surface temperatures during July 2009 were warmer than average across much of the world's oceans, with the exception of cooler-than-average conditions across parts of the North Atlantic Ocean and the southern oceans. Sea surface temperature anomalies in all Niño regions continued to warm during July 2009, where the monthly temperatures were more than 0.5°C (0.9°F) above average. If El Niño conditions continue to mature as projected by NOAA, global temperatures are likely to continue to threaten previous record highs. Please see the July 2009 ENSO discussion for additional information.
The January-July 2009 map of temperature anomalies shows the presence of warmer-than-average conditions across much of the world's land areas, with the exception of cooler-than-average temperatures across Canada and parts of the northern contiguous United States. Sea surface temperatures were warmer than average across all oceans, with cooler-than-average SSTs present across the central equatorial Pacific Ocean, along the western coast of North America, and the southern oceans.
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 July 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
The combined global land and ocean surface temperature was the fifth warmest on record in July and tied with 2004 as the sixth warmest on record for the year-to-date (January-July) period. The global land surface tied with 2003 as the ninth warmest July on record, while the global ocean surface had the warmest July on record. The ranks found in the tables below are based on records that began in 1880.
(out of 130 years)
|(Next) Warmest on Record|
|Land and Ocean||+0.57||+1.03||5th warmest||1998||+0.70||+1.26|
|Land and Ocean||+0.59||+1.06||5th warmest*||2005*||+0.74||+1.33|
|Land and Ocean||+0.56||+1.01||2nd warmest||1998||+0.66||+1.19|
*Signifies a tie
(out of 130 years)
|Warmest on Record|
|Land and Ocean||+0.54||+0.97||6th warmest*||1998||+0.67||+1.21|
|Land and Ocean||+0.58||+1.04||6th warmest*||2007||+0.75||+1.35|
|Land and Ocean||+0.50||+0.90||5th warmest||1998||+0.64||+1.15|
*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. During July 2009, above-average precipitation fell over areas that included the British Isles, parts of Europe, western India, eastern Asia, southern Brazil, and the central and northeastern contiguous United States. The driest anomalies occurred across northern India, west central Africa, and southern Chile.
According to Environment Canada, Ottawa's International Airport set an all-time monthly record when 243.4 mm (9.6 in) of rain fell in July 2009, surpassing the previous all-time record of 224.8 mm (8.8 in) in June 2002. This value also shattered the previous July rainfall record of 186.4 mm (7.3 in) set on 1972. Earlton, Ontario, Canada experienced its wettest July since 1969 (Source: Environment Canada).
Australia—as a whole—experienced 37 percent below-average rainfall during July. The state of Queensland had its fifth lowest precipitation on record for July, with some locations in eastern Queensland recording their driest July on record. While much of the country had below-average rainfall during July 2009, southern parts of the country had wetter-than-average conditions. Tasmania had its highest July precipitation since 2002 and South Australia's agricultural area experienced its highest July precipitation since 1996. (Source: Australia's Bureau of Meteorology).
Other notable precipitation extremes during July 2009 include copious monsoon rainfall in Dhaka, Bangladesh, which received 290 mm (11.4 in) of rain on July 29th, its largest daily rainfall in July since 1949. In southern China, heavy rain fell during July, prompting rivers to overflow their banks and triggering landslides and floods. The excessive rains were responsible for 66 fatalities and affected tens of thousands of people.
Additional details on flooding and drought can also be found on the July 2009 Global Hazards page.
ENSO SST Analysis
Sea surface temperatures continued to warm across the equatorial Pacific during July 2009, resulting in anomalies greater than 0.5°C (0.9°F) above average in all Niño regions. The Oceanic Niño Index (three-month [May-June-July] running average) was +0.6°C (1.1°F), which is above the threshold of +0.5°C (+0.9°F). These conditions are indicative of a developing El Niño. A comprehensive summary of July 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.