Global Analysis - April 2011
Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective September 2012, the GHCN-M version 3.2.0 dataset of monthly mean temperature replaced the GHCN-M version 3.1.0 monthly mean temperature dataset. Beginning with the August 2012 Global monthly State of the Climate Report, released on September 17, 2012, GHCN-M version 3.2.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends. For more information about this newest version, please see the GHCN-M version 3.2.0 Technical Report.
*The GHCN-M version 3.1.0 Technical Report was revised on September 5, 2012 to accurately reflect the changes incorporated in that version. Previously that report incorrectly included discussion of changes to the Pairwise Homogeneity Algorithm (PHA). Changes to the PHA are included in version 3.2.0 and described in the version 3.2.0 Technical Report. Please see the Frequently Asked Questions to learn more about this update.
Contents of this Section:
- The combined global land and ocean average surface temperature for April 2011 was the seventh warmest April on record at 14.29°C (57.76°F), which is 0.59°C (1.06°F) above the 20th century average of 13.7°C (56.7°F). This was also the 35th consecutive April with global land and ocean temperatures above the 20th century average.
- The worldwide ocean surface temperature was 0.38°C (0.68°F) above the 20th century average of 16.0°C (60.9°F) and the 11th warmest April on record.
- The April worldwide land surface temperature was 1.12°C (2.02°F) above the 20th century average of 8.1°C (46.5 °F)—the 6th warmest on record.
- For the year-to-date, the global combined land and ocean surface temperature of 13.08°C (55.66°F) was the 14th warmest January–April period. This value is 0.48°C (0.86°F) above the 20th century average.
Temperature anomalies for April 2011 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 1961–90 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). For the merged land surface and SST analysis, temperature anomalies with respect to the 1971–2000 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.
April 2011 was characterized by warm conditions across much of the world, particularly across land areas. The warmest anomalies occurred over most of the southern United States and northern Mexico, much of central South America, Europe, northwestern Africa, and most of Russia. Cooler-than-average conditions prevailed across most of Alaska, western Canada, the northwestern United States, southwestern Greenland, and most of Australia. The worldwide land temperatures for April 2011 ranked as the sixth warmest on record, 1.12°C (2.02°F) above the 20th century average.
Warmer-than-average conditions enveloped much of the world's oceans, with cooler-than-average conditions across parts of the eastern and central Pacific Ocean, the western tropical Pacific, the South China Sea, and much of the southern oceans. Although temperature anomalies across the equatorial Pacific Ocean remained less than 0.5°C (0.9°F) on average, La Niña weakened during April as temperature anomalies warmed across the region. Globally, sea surface temperatures (SST) during April were the 11th warmest on record, with an anomaly of 0.39°C (0.70°F) above the 20th century average. Notably, this was the warmest La Niña April on record (since 1950). According to NOAA's Climate Prediction Center (CPC), a transition to El Niño Southern Oscillation (ENSO)-neutral conditions is expected by June 2011 and to continue through the Northern Hemisphere summer 2011.
Overall, the combined global land and ocean surface temperature anomaly for April 2011 was the seventh warmest April since records began in 1880. The combined global land and ocean temperature anomaly was 0.59°C (1.06°F) above the 20th century average.
Did You Know?
Global Historical Climatology Network
NOAA's National Climatic Data Center (NCDC) has developed and maintained the Global Historical Climatology Network-Monthly (GHCN-M) data set since 1992 (Vose et al. 1992). The GHCN-M data set was created with the intention of having a single repository of climate data for stations across the globe. In 1997, a second version (GHCN-M v2) of the data set was developed and released with improvements such as quality control and removal of inhomogeneities in the data record (non-climatic influences that could produce a false trend) and an increased number of stations and length of the data record (Peterson and Vose, 1997).
The GHCN-M v2 has been the official dataset since its release, and has been widely used in several international climate assessments, such as the Intergovernmental Panel on Climate Change, as well as our monthly State of the Climate reports and in the yearly State of the Climate published in the Bulletin of the American Meteorological Society.
NCDC scientists continued to improve the data set, resulting in a version 3 of GHCN-M. The primary advances in GHCN-M v3, versus GHCN-M v2, are further improvements to quality control processes, more advanced techniques for removing data inhomogeneities, and improved station coverage. For more information about the differences between versions 2 and 3, please visit the GHCN-Monthly website.
On May 2, 2011, NCDC transitioned to GHCN-M v3 as the official land component of its global temperature monitoring efforts. GHCN-M v2 will continue to be updated through May 30, 2011, but no support for this version of the dataset will be provided.
The April 2011 average temperature for the Northern Hemisphere as a whole (land and ocean surface combined) was 0.73°C (1.31°F) above the 20th century average—the sixth warmest April on record. The Northern Hemisphere ocean temperature during April tied with 2008 as the 12th warmest on record, with an anomaly of 0.34°C (0.61°F) above the 20th century average. The Northern Hemisphere land tied with 2005 as the fourth warmest on record. This value is 1.38°C (2.48°F) above the 20th century average.
Parts of Western Europe reported record or near-record warmth during April. It was the warmest April on record across the United Kingdom, with temperatures 3°C–5°C (5°F–9°F) above normal in many areas, breaking the previous record set in 2007 by 0.5°C (0.9°F). Germany experienced its second warmest April since national records began in 1881, behind April 2009. Average nationwide temperatures were almost 4.4°C (7.9°F) above average.
The average temperature for the Southern Hemisphere as a whole (land and ocean surface combined) was 0.44°C (0.79°F) above the 20th century average—the 13th warmest April on record. The Southern Hemisphere ocean temperature during April tied with 2000 as the 10th warmest on record, with an anomaly of 0.44°C (0.79°F) above the 20th century average. The April Southern Hemisphere land temperature was 0.43°C (0.77°F) above the 20th century average—the 25th warmest April on record.
Temperatures remained below normal across Australia's continent as a whole during April. Maximum daily temperatures were 0.67°C (1.20°F) below average, marking the 14th lowest April maximum temperatures on record, while April daily minimum temperatures were 0.96°C (1.73°F) below average, the 10th lowest on record.
The January–April 2011 map of temperature anomalies shows that, for the first four months of the year, anomalous warm temperatures were present over much of the world, with the exception of cooler-than-average conditions across central Canada, the northern United States, western Russia, Kazakhstan, Mongolia, extreme southeast Asia, and most of Australia. The combined global land and ocean surface temperature for the January–April period was the 14th warmest such period on record. This value is 0.48°C (0.86°F) above the 20th century average. Separately, the worldwide land surface temperature ranked as the 17th warmest on record, while the worldwide ocean surface temperature ranked as the 11th warmest January–April on record.
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 April 2011 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 2011 from the weekly SST page.
Temperature Rankings and Graphics
(out of 132 years)
|Warmest on Record|
|Land||+1.12 ± 0.11||+2.02 ± 0.20||6th warmest||2007||+1.44||+2.59|
|Ocean||+0.39 ± 0.04||+0.70 ± 0.07||11th warmest||2010||+0.57||+1.03|
|Land and Ocean||+0.59 ± 0.07||+1.06 ± 0.13||7th warmest||2010||+0.78||+1.40|
|Land||+1.38 ± 0.15||+2.48 ± 0.27||4th warmest*||2000||+1.62||+2.92|
|Ocean||+0.34 ± 0.04||+0.61 ± 0.07||12th warmest*||2010||+0.59||+1.06|
|Land and Ocean||+0.73 ± 0.11||+1.31 ± 0.20||6th warmest||2010||+0.94||+1.69|
|Land||+0.43 ± 0.14||+0.77 ± 0.25||25th warmest||2005||+1.06||+1.91|
|Ocean||+0.44 ± 0.04||+0.79 ± 0.07||10th warmest*||1998||+0.61||+1.10|
|Land and Ocean||+0.44 ± 0.06||+0.79 ± 0.11||13th warmest||1998||+0.66||+1.19|
*Signifies a tie
* Northern Hemisphere Land tied with 2005 as 4th warmest on record.
* Northern Hemisphere Ocean tied with 2008 as 12th warmest on record.
* Southern Hemisphere Ocean tied with 2000 as 10th warmest on record.
(out of 132 years)
|Warmest on Record|
|Land||+0.74 ± 0.20||+1.33 ± 0.36||17th warmest||2007||+1.38||+2.48|
|Ocean||+0.38 ± 0.04||+0.68 ± 0.07||11th warmest||2010*||+0.56||+1.01|
|Land and Ocean||+0.48 ± 0.09||+0.86 ± 0.16||14th warmest||2010||+0.72||+1.30|
|Land||+0.89 ± 0.25||+1.60 ± 0.45||16th warmest*||2007||+1.58||+2.84|
|Ocean||+0.34 ± 0.05||+0.61 ± 0.09||8th warmest*||2010||+0.55||+0.99|
|Land and Ocean||+0.55 ± 0.13||+0.99 ± 0.23||13th warmest*||2007||+0.89||+1.60|
|Land||+0.35 ± 0.14||+0.63 ± 0.25||25th warmest*||2010||+1.00||+1.80|
|Ocean||+0.42 ± 0.04||+0.76 ± 0.07||12th warmest*||1998||+0.60||+1.08|
|Land and Ocean||+0.41 ± 0.07||+0.74 ± 0.13||14th warmest*||1998||+0.65||+1.17|
*Signifies a tie
* Northern Hemisphere Land tied with 2003 as 16th warmest on record.
* Northern Hemisphere Ocean tied with 2001, 2007, and 2009 as 8th warmest on record.
* Northern Hemipshere Land and Ocean tied with 2006 as 13th warmest on record.
* Southern Hemisphere Land tied with 1958 as 25th warmest on record.
* Southern Hemisphere Ocean tied with 1988 as 12th warmest on record.
* Southern Hemisphere Land and Ocean tied with 1992 as 14th warmest on record
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 1961–90. Precipitation anomalies on a month-to-month basis are often highly variable across the globe and even within regions. The areas with the wettest anomalies during April 2011 included a large portion of the eastern United States, most of South America, southern India, and some coastal regions in Australia. The driest anomalies were present across most of Europe, southern China, Hawaii, parts of French Polynesia, and part of eastern Australia.
Average rainfall across Australia was 18 percent above average during April. However, for the first month since June 2010, below-average rainfall was reported in the states of Queensland, South Australia, and New South Wales.
For more information about the GHCN monthly gridded products, please click here.
Additional details on flooding and drought can also be found on the April 2011 Global Hazards 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.