Global Highlights:
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Contents of this Section: |
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.
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IntroductionTemperature anomalies for April 2007 are shown
on the dot maps below. The dot map, 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 map, below right,
is 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 have covered
much of the globe throughout the year. The
January-April 2007 map of temperature anomalies shows the
presence of warmer than average temperatures across all land areas,
with the exception of Alaska. Additional information on Alaska
temperatures are available on the U.S. National
page. Warmer than average Sea Surface Temperatures (SST)
occured in the equatorial Pacific, North and South Atlantic and the
Indian Ocean. Cooler than average conditions were observed in the
northeastern Pacific and some areas in the South Pacific.
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During April, there were above average
temperatures across Europe, Alaska, western U.S., eastern Brazil,
northwestern Africa, and most of Asia. Cooler-than-average
conditions occurred in the Middle East Region and the eastern half
of the contiguous U.S. Warmer than average SSTs occurred in the
Atlantic Ocean, North Indian Ocean, and the Northwestern Pacific
Ocean. In the Niño
regions, SST anomalies were in the range of average or slightly
below average with the exception of the Niño 4 region where
SST anomalies were slightly above average. These conditions are
indicative of a persisting neutral ENSO phase. Please see the
latest ENSO
discussion for additional information.
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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 April 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.
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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).
April 2007 ranked as the third warmest April
since records began in 1880 for combined global land and ocean
surface temperatures. The April land surface temperature ranked
warmest on record, while ocean surface temperature ranked seventh
warmest in the 127-year record. For the January-April year-to-date
period, the global surface temperature ranked warmest on
record.
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Current Month / Year-to-date |
April | Anomaly | Rank | Warmest (or Next Warmest) Year on Record |
Ties |
---|---|---|---|---|
GlobalLandOcean Land and Ocean |
+1.37°C (+2.47°F) +0.41°C (+0.74°F) +0.67°C (+1.21°F) |
warmest 7th warmest 3rd warmest |
2000 (+1.30°C/2.34°F) 1998 (+0.53°C/0.95°F) 1998 (+0.70°C/1.26°F) |
2001 |
Northern HemisphereLandOcean Land and Ocean |
+1.57°C (+2.83°F) +0.43°C (+0.77°F) +0.86°C (+1.55°F) |
2nd warmest 4th warmest warmest |
2000 (+1.66°C/2.99°F) 2004 (+0.53°C/0.95°F) 2005 (+0.81°C/1.46°F) |
2002 |
Southern HemisphereLandOcean Land and Ocean |
+0.79°C (+1.42°F) +0.40°C (+0.72°F) +0.45°C (+0.81°F) |
9th warmest 9th warmest 8th warmest |
1992 (+1.41°C/2.54°F) 1998 (+0.59°C/1.06°F) 1988 (+0.63°C/1.13°F) |
1983 |
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January-April | Anomaly | Rank | Warmest (or Next Warmest) Year on Record |
Ties |
---|---|---|---|---|
GlobalLandOcean Land and Ocean |
+1.35°C (+2.43°F) +0.44°C (+0.79°F) +0.69°C (+1.24°F) |
warmest 6th warmest warmest |
2002 (+1.29°C/2.32°F) 1998 (+0.53°C/0.95°F) 2002 (+0.68°C/1.22°F) |
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Northern HemisphereLandOcean Land and Ocean |
+1.56°C (+2.81°F) +0.46°C (+0.83°F) +0.88°C (+1.58°F) |
warmest 3rd warmest warmest |
2002 (+1.54°C/2.77°F) 2004 (+0.50°C/0.90°F) 2002 (+0.83°C/1.49°F) |
2005 |
Southern HemisphereLandOcean Land and Ocean |
+0.72°C (+1.30°F) +0.43°C (+0.77°F) +0.47°C (+0.85°F) |
4th warmest 7th warmest 6th warmest |
2005 (+0.89°C/1.60°F) 1998 (+0.56°C/1.01°F) 1998 (+0.61°C/1.10°F) |
2001 |
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PrecipitationThe maps below represent anomaly values based
on the GHCN data set of land surface stations using a base period
of 1961-1990. During April 2007, above average precipitation fell
over areas that include the Northeast region of the contiguous U.S.
and most of South America. Drier than average conditions were
observed in Japan, southeastern U.S., southeastern China and most
of Europe. Additional details on flooding and drought can also be
found on the April Global Hazards
page.
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ENSO SST AnalysisClick here for animated loop |
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ReferencesPeterson, 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. |