State of the Climate
Global Analysis
August 2004
National Oceanic and Atmospheric Administration
National Climatic Data Center
Use the form below to access monthly reports.
Global Highlights:
- Based on preliminary data, global average combined land and sea
surface temperature was sixth warmest on record for both August and
June-August 2004
- June-August temperatures were above average throughout Europe,
Alaska and the western U.S., with below average temperatures in the
central U.S. and southwestern Australia
- Precipitation during June-August was above average across the
eastern U.S., western Europe and parts of Scandinavia, with drier
than average conditions in India, eastern Australia and parts of
Alaska
- Sea Surface Temperatures (SSTs) continued to increase in the
western and central tropical Pacific
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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. |
Introduction
The two maps below utilize different base periods and may reflect
different anomaly values of land surface temperatures. The dot map
on the left uses anomalies that were 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
blended product
which uses satellite and surface anomaly values of measured land
and ocean temperatures as well as SSTs with the base period of
1988-2004. Both maps reflect conditions during summer 2004,
indicating above average temperatures in Alaska, Mongolia,
Argentina and Iceland, with cooler than average temperatures over
most of the U.S., parts of far eastern Russia and portions of
Brazil. During the month of August
2004, above average temperatures occurred in Europe, the
pacific northwest of the U.S. and Alaska while cooler than average
conditions occurred in the central portion of the U.S., parts of
Brazil and western Australia.
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 June-August 2004
and August 2004 maps)
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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Temperature Rankings and Graphics
Current Month / Seasonal /
Year-to-date
| August |
Anomaly |
Rank |
Warmest Year on
Record |
Global
Land
Ocean
Land and Ocean |
+0.47°C (+0.85°F)
+0.42°C (+0.76°F)
+0.44°C (+0.80°F) |
12th warmest
4th warmest
6th warmest |
1998
(+0.97°C/1.75°F)
1998 (+0.50°C/0.90°F)
1998 (+0.64°C/1.15°F) |
Northern Hemisphere
Land
Ocean
Land and Ocean |
+0.62°C (+1.12°F)
+0.58°C (+1.04°F)
+0.59°C (+1.06°F) |
8th warmest
3rd warmest
4th warmest |
2003
(+1.08°C/1.94°F)
2003 (+0.61°C/1.10°F)
2003 (+0.80°C/1.44°F) |
Southern Hemisphere
Land
Ocean
Land and Ocean |
+0.05°C (+0.09°F)
+0.31°C (+0.56°F)
+0.26°C (+0.47°F) |
49th warmest
7th warmest
12th warmest |
1884
(+1.42°C/2.56°F)
1998 (+0.42°C/0.76°F)
1998 (+0.47°C/0.85°F) |
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| June-August |
Anomaly |
Rank |
Warmest Year on
Record |
Global
Land
Ocean
Land and Ocean |
+0.56°C (+1.01°F)
+0.37°C (+0.67°F)
+0.42°C (+0.76°F) |
9th warmest
5th warmest
6th warmest |
1998
(+0.97°C/1.75°F)
1998 (+0.50°C/1.00°F)
1998 (+0.64°C/1.15°F) |
Northern Hemisphere
Land
Ocean
Land and Ocean |
+0.60°C (+1.08°F)
+0.50°C (+0.90°F)
+0.54°C (+0.97°F) |
10th warmest
2nd warmest
5th warmest |
1998
(+1.00°C/1.80°F)
1998 (+0.56°C/1.01°F)
1998 (+0.73°C/1.31°F) |
Southern Hemisphere
Land
Ocean
Land and Ocean |
+0.34°C (+0.61°F)
+0.28°C (+0.50°F)
+0.29°C (+0.52°F) |
16th warmest
10th warmest
11th warmest |
1998
(+0.81°C/1.46°F)
1998 (+0.46°C/0.83°F)
1998 (+0.53°C/0.95°F) |
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| January-August |
Anomaly |
Rank |
Warmest Year on
Record |
Global
Land
Ocean
Land and Ocean |
+0.80°C (+1.44°F)
+0.38°C (+0.68°F)
+0.51°C (+0.92°F) |
5th warmest
4th warmest
4th warmest |
2002
(+1.09°C/1.96°F)
1998 (+0.51°C/0.92°F)
1998 (+0.68°C/1.22°F) |
Northern Hemisphere
Land
Ocean
Land and Ocean |
+0.89°C (+1.60°F)
+0.46°C (+0.83°F)
+0.63°C (+1.13°F) |
5th warmest
2nd warmest
3rd warmest |
2002
(+1.21°C/2.18°F)
1998 (+0.53°C/0.95°F)
1998 (+0.77°C/1.39°F) |
Southern Hemisphere
Land
Ocean
Land and Ocean |
+0.43°C (+0.77°F)
+0.34°C (+0.61°F)
+0.36°C (+0.65°F) |
9th warmest
6th warmest
7th warmest |
1998
(+0.87°C/1.57°F)
1998 (+0.51°C/0.92°F)
1998 (+0.58°C/1.04°F) |
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The most current data may be accessed via the Global Surface
Temperature Anomalies 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. The map
to the left is precipitation anomalies measured in millimeters, the
map to the right is the percentage of average (1961-1990)
precipitation. During June-August 2004, much above average
precipitation fell across the eastern half of the U.S., Scandinavia
and western Europe. Below average precipitation was observed in
Alaska, India and eastern Australia. During the month of August
2004, above average precipitation occurred in the southeastern
U.S., Chile and coastal Alaska while drier than average conditions
were observed in the southern Brazil, Malaysia and Norway. |
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The satellite images below were acquired from SSM/I satellite data
using a base period of 1988-2004. The map on the left reflects
surface liquid wetness conditions, while the map on the right
reflects snow cover conditions for the month. Snow covered areas
that are normally snow-free during this month will appear drier
than average on the wetness image since a wetness value cannot be
determined for regions that are snow covered. Data in these areas
that are normally snow covered are displayed as missing. This is
due to the snow crystalline structure which produces a considerable
amount of scatter and makes it difficult for the SSM/I to
accurately detect the surface conditions. The SSM/I products are
experimental and are under continuing review and development.
Additional data and information can be found on the SSM/I Browser. |
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ENSO SST Analysis
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- Sea Surface Temperatures (SSTs) continued to increase in the
western and central tropical Pacific, as an equatorial Kelvin wave
moved across the basin during August (as shown in the adjacent
animation of weekly sea surface temperature anomalies). A
comprehensive summary of August 2004 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 months to date during 2004 at the weekly SST page
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Troposphere
Current Month / Seasonal
The tables below summarize mid-tropospheric conditions for August
and June-August 2004. 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.) Analysis of the satellite record that began
in 1979 indicates that global temperatures are increasing in the
mid-troposphere, but the magnitude of the trend differs based on
the analysis methods used in adjusting for factors such as orbital
decay and inter-satellite differences. The 1979-2004 trend for
August and June-August is 0.05°C/decade based on data from the
University of Alabama at Huntsville (UAH). Based on data provided
by Remote Sensing Systems (RSS) the trend for August and
June-August is 0.13°C/decade. The base period used in both data
sets is 1979-1998. |
|
August |
Anomaly |
Rank |
Warmest Year on
Record |
| UAH mid-troposphere |
-0.06°C (-0.11°F) |
11th coolest |
1998
(+0.44°C/0.80°F) |
| RSS mid-troposphere |
+0.10°C (+0.18°F) |
9th warmest |
1998
(+0.51°C/0.92°F) |
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| June-August |
Anomaly |
Rank |
Warmest Year on
Record |
| UAH mid-troposphere |
-0.08°C (-0.14°F) |
10th coolest |
1998
(+0.47°C/0.85°F) |
| RSS mid-troposphere |
+0.10°C (+0.18°F) |
10th warmest |
1998
(+0.54°C/0.97°F)
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Stratosphere
Current Month /
Seasonal
The tables below summarize stratospheric conditions for August and
June-August 2004. The stratosphere is located 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 in both data sets is 1984-1990 which
was chosen to avoid contamination by these eruptions. |
|
August |
Anomaly |
Rank |
Warmest Year on
Record |
| UAH stratosphere |
-0.37°C (-0.67°F) |
7th coolest |
1991
(+1.12°C/2.02°F) |
| RSS stratosphere |
-0.28°C (-0.50°F) |
11th coolest |
1991
(+0.94°C/1.70°F) |
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| June-August |
Anomaly |
Rank |
Warmest Year on
Record |
| UAH stratosphere |
-0.35°C (-0.63°F) |
7th warmest |
1982
(+0.91°C/1.64°F) |
| RSS stratosphere |
-0.18°C (-0.32°F) |
12th warmest |
1982
(+0.83°C/1.50°F)
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| Mid-tropospheric and lower stratospheric temperature data are
collected by NOAA's TIROS-N polar-orbiting satellites and adjusted
for time-dependent biases by NASA and 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). |
| For additional details on precipitation and temperatures in
August, see the Global Hazards page . |
References:
Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global
Historical Climatology Network Database. Bull. Amer. Meteorol.
Soc., 78, 2837-2849.
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