Climate Monitoring / Climate of 2006 / April / Global / Help

Climate of 2006 - April in Historical Perspective



National Climatic Data Center
15 May 2006
Global Analysis / Global Hazards / United States / U.S. Drought / Extremes
Use these links to access detailed analyses of Global and U.S. data.

Global Highlights:

  • Based on preliminary data, globally averaged combined land and sea surface temperature was 7th warmest on record for April 2006.
  • April 2006 temperatures were above average in Europe, southeastern China and the majority of North America. Colder-than-average conditions occurred in Japan, coastal Alaska, and central Russia.
  • Precipitation during April 2006 was above average in the U.S. northern Rockies, northern Australia and much of the Amazon Basin, with drier-than-average conditions in eastern Australia, the southern U.S. and Malaysia.
  • The transition from La Niña conditions to neutral ENSO conditions continued.

Contents of this Section:
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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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Top of Page Introduction

Temperature anomalies for April 2006 are shown on the two maps below. The dot map on the 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 map on the right is a product of a merged land surface and sea surface temperature anomaly analysis which is based on data from the GHCN of land temperatures and the Comprehensive Ocean-Atmosphere Data Set (COADS) of Sea-Surface Temperature (SST) data. Temperature anomalies with respect to 1961-1990 for land and ocean are analyzed separately and then merged to form the global analysis. Additional information on this product is available.

During April 2006, there were above average temperatures in Algeria, Scandinavia, Iran, eastern Europe, eastern China, and the majority of North America. Cooler than average temperatures were observed in Pakistan, Japan, northeastern China, coastal Alaska and central Russia.

During January-April 2006, there were above average temperatures in the majority of North America, central Africa, much of Asia and Greenland. Cooler than average temperatures were observed in eastern Europe, Alaska and Russia.

In January-April and April 2006, warmer than average SSTs occurred in the South Pacific and the North Atlantic. In January-April 2006, cooler than average conditions were observed in the Niño 3.4 region, and the western coast of Australia. In April 2006, cooler than average conditions were observed in the North Pacific and the Niño 1+2 region. Please see the latest ENSO discussion for further information.

Current month's Land SurfaceTemperature Dot map
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Current month's blended Land and sea surface Temperature Dot map
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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 2006 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.

Images of sea surface temperature conditions are available for all weeks during 2006 at the weekly SST page.

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Top of Page Temperature Rankings and Graphics

Effective with the January 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.
Current Month / Year-to-date
April Anomaly Rank Warmest Year on Record

Global

Land
Ocean
Land and Ocean
+0.56°C (+1.01°F)
+0.41°C (+0.74°F)
+0.45°C (+0.81°F)
13th warmest
6th warmest
8th warmest
2000 (+1.30°C/2.34°F)
1998 (+0.53°C/0.95°F)
1998 (+0.70°C/1.26°F)

Northern Hemisphere

Land
Ocean
Land and Ocean

+0.65°C (+1.17°F)
+0.40°C (+0.72°F)
+0.49°C (+0.88°F)

11th warmest
6th warmest
7th warmest

2000 (+1.66°C/2.99°F)
2004 (+0.53°C/0.95°F)
2005 (+0.83°C/1.49°F)

Southern Hemisphere

Land
Ocean
Land and Ocean

+0.28°C (+0.50°F)
+0.43°C (+0.77°F)
+0.41°C (+0.74°F)

32nd warmest
7th warmest
9th warmest

1992 (+1.41°C/2.54°F)
1998 (+0.59°C/1.06°F)
1998 (+0.63°C/1.13°F)

Global Land and Ocean Triad plot
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Global Hemisphere Triad plot
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January-April Anomaly Rank Warmest Year on Record

Global

Land
Ocean
Land and Ocean
+0.70°C (+1.26°F)
+0.39°C (+0.70°F)
+0.47°C (+0.85°F)
12th warmest
6th warmest
6th warmest
2002 (+1.29°C/2.32°F)
1998 (+0.53°C/0.95°F)
2002 (+0.66°C/1.19°F)

Northern Hemisphere

Land
Ocean
Land and Ocean

+0.76°C (+1.37°F)
+0.34°C (+0.61°F)
+0.50°C (+0.90°F)

12th warmest
6th warmest
9th warmest

2002 (+1.55°C/2.79°F)
2004 (+0.50°C/0.90°F)
2002 (+0.83°C/1.49°F)

Southern Hemisphere

Land
Ocean
Land and Ocean

+0.52°C (+0.94°F)
+0.44°C (+0.79°F)
+0.45°C (+0.81°F)

8th warmest
6th warmest
6th warmest

2005 (+0.89°C/1.60°F)
1998 (+0.56°C/1.01°F)
1998 (+0.61°C/1.10°F)

Global Land and Ocean Triad plot
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Global Hemisphere Triad plot
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The most current data may be accessed via the Global Surface Temperature Anomalies page.

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Top of Page Precipitation

The maps below represent anomaly values based on the GHCN data set of land surface stations using a base period of 1961-1990. During April 2006, above average precipitation fell over areas that include Colombia, Chile, South Africa, Burma, Thailand, northeastern Australia, the U.S. northern Rockies and most of northern Brazil. Heavy rain and flooding occurred in parts of Colombia, Yemen, eastern Europe, Agentina, and Indonesia as discussed on the April Hazards page. Below average precipitation was observed in Liberia, Malaysia, the eastern coast of Australia, the southern U.S. and southern Europe. Additional details on drought can also be found on the April Hazards page.


Precipitation Dot map in Millimeters for April
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Percent Precipitation Dot map for April
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Top of Page ENSO SST Analysis




Last week of the month's ENSO condtions Map
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  • Sea Surface Temperatures were cooler than average across the central tropical Pacific. However, during April La Niña conditions dissipated, indicating a more neutral state of ENSO (shown in the adjacent animation of weekly sea surface temperature anomalies). A comprehensive summary of April 2006 ENSO conditions can be found on the ENSO monitoring page. For the latest advisory on ENSO conditions go to NOAA's Climate Prediction Center (CPC) and the CPC ENSO Diagnostic Discussion

  • Images of sea surface temperature conditions are available for all weeks during 2006 at the weekly SST page

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Top of Page Troposphere

Current Month
Mid-tropospheric and lower stratospheric temperature data are collected by NOAA's TIROS-N polar-orbiting satellites and adjusted for time-dependent biases 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 the University of Washington (UW) (Fu et al. 2004)** to remove the influence of the stratosphere on the mid-troposphere value.

The table below summarizes mid-tropospheric conditions for April 2006. These temperatures are for the atmospheric layer centered in the mid-troposphere (approximately 2-6 miles above the Earth's surface) which also includes a portion of the lower stratosphere. (The MSU channel used to measure mid-tropospheric temperatures receives about 25 percent of its signal above 6 miles). For additional information on MSU data used in this report, please see the Microwave Sounding Unit page.

All datasets indicate boreal winter temperatures and April temperatures were above average. Records began in 1979.


April Anomaly Rank Warmest Year on Record Trend
UAH mid-trop +0.15°C/0.27°F 7th warmest 1998 (+0.71°C/1.28°F) +0.06°C/decade
*RSS mid-trop +0.14°C/0.25°F 9th warmest 1998 (+0.78°C/1.40°F) +0.13°C/decade
**UW-UAH mid-trop +0.25°C/0.45°F 4th warmest 1998 (+0.84°C/1.51°F) +0.13°C/decade
**UW-*RSS mid-trop +0.24°C/0.43°F 7th warmest 1998 (+0.92°C/1.66°F) +0.19°C/decade
*Version 02_1


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Top of Page Stratosphere

Current Month
The table below summarizes stratospheric conditions for April 2006. On average, the stratosphere is located approximately between 10-14 miles above the Earth's surface. Over the last decade, stratospheric temperatures have been below average in large part due to the depletion of ozone. The large increase in temperature in 1982 was caused by the volcanic eruption of El Chichon in Mexico, and the increase in 1991 was a result of the eruption of Mt. Pinatubo in the Philippines. Therefore the base period used is 1984-1990 which was chosen to avoid contamination by these eruptions.

April Anomaly Rank Coolest Year on Record
UAH stratosphere -0.52°C (-0.94°F) 3rd coolest 1999 (-0.66°C/-1.19°F)
*RSS stratosphere -0.43°C (-0.77°F) 5th coolest 1998 (-0.61°C/-1.10°F)
*Version 02_1


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For additional details on precipitation and temperatures in April, see the Global Hazards page.
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Top of Page References

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.

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.

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.
For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:

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fax: 828-271-4876
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For questions about this report, please contact:

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fax: 828-271-4328
email: Jay.Lawrimore@noaa.gov
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email: David.Easterling@noaa.gov
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