PLEASE NOTE: The ranks and temperature anomalies in this report represent the values known at the time the report was issued. The actual ranks will change as subsequent years are added to the dataset. The anomalies themselves may change slightly as missing or erroneous data is resolved. Also, in 2009, NCDC switched to ERSST version 3b (from version 2) as a component of its global surface temperature dataset. Because the versions have slightly different methodologies, the calculated temperature anomalies will differ slightly. For more information about this switch please see the Global Surface Temperature Anomalies FAQ .
Global Temperatures
| Global
temperatures in 2003 were 0.56°C (1.01°F) above the
long-term (1880-2003) average**, ranking 2003 the second warmest
year on record, which tied 2002. The warmest year on record is 1998
with an anomaly of +0.63°C (+1.13°F). Land temperatures in
2003 were 0.83°C (1.50°F) above average, ranking third in
the period of record while ocean temperatures ranked as second
warmest with 0.44°C (0.80°F) above the 1880-2003 mean. |
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|
|
The map of temperature anomalies (above right) contains data
from an in-situ and satellite blended data set of land and ocean
temperatures. The period of record for this data set is 1988-2002,
a relatively warm period compared to the base period used in the
creation of the land
only map of temperature anomalies below. Some minor differences
in the land surface anomalies between these two maps result from
the differences in base periods and data that are used to construct
the two maps.
The
Northern Hemisphere temperature averaged near record levels in
2003 at 0.64°C (1.15°F) above the long-term average. The
Southern Hemisphere temperature also reflected the globally
warmer conditions, with a positive anomaly near 0.45°C
(0.81°F).
Annual anomalies in excess of +2.0°C (3.6°F) were
widespread across much of North America, Asia and Europe.
Additional details on temperatures throughout the world are
included below.
**The 1880-2003 average combined land and ocean annual
temperature is 13.9°C (56.9°F), the annually averaged land
temperature for the same period is 8.5°C (47.3°F), and the
long-term annually averaged sea surface temperature is 16.1°C
(60.9°F).
|
ENSO Conditions
| The year began with
the equatorial Pacific Ocean in an El Niño/Southern
Oscillation (ENSO) warm event. This El Niño warming began in
mid-2002, and reached its maturity in November 2002 when the
sea-surface temperature (SST) anomalies in the Niño
3.4 region (map of
Niño regions) reached their warmest condition with a
+1.54°C (+2.77°F) SST anomaly. |
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| Beginning in January of 2003, the anomalously warm
waters in the oceanic mixed-layer in the eastern equatorial Pacific
began to slowly cool. Between December 2002 and January 2003, the
SST anomaly in the Niño 3.4 region decreased from
+1.42°C (+2.55°F) to +0.66°C (+1.18°F). This
cooling spread westward, and had affected the ocean conditions
basin-wide in the February monthly mean ocean temperatures. The
trend in SST anomalies was also evident in the western Pacific
Ocean, reflected in the anomalies measured in the Niño
4 region. The observed cooling trend in basin-wide SSTs
continued through March. The dissipation of the warm event and the
transition to near-neutral ENSO conditions occurred in April, when
the SST anomalies cooled to near-normal across the equatorial
Pacific basin. However, the atmospheric signal lagged the ocean,
with the
Southern Oscillation Index (SOI) remaining negative through
June (see discussion below). This trend in ocean temperatures is
illustrated in the loop of
Equatorial Pacific SSTs, which shows the mean and anomalous
conditions across the tropical Pacific Ocean for the period
December 2002 through December 2003. |
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|
After the El
Niño event dissipated in April, ocean surface and
sub-surface temperatures began to rapidly cool. This cooling
suggested the development of a La Niña cold event in the
eastern and central equatorial Pacific. By the end of
May, SST anomalies in the eastern and central equatorial
Pacific had cooled to below -1.5 °C adjacent to the South
American coast. The cold anomaly in the Niño
3.4 region was -0.63°C (-1.13°F) in May. The rapid
cooling was generated by the return of easterly trade winds across
the near-equatorial region, which increased equatorial upwelling in
the eastern Pacific in April and May. |
| The colder than normal SST anomalies extended into
the middle of June, but were abruptly halted when a strong westerly
wind event propagated across the equatorial Pacific basin. This
westerly wind event (often referred to as wind bursts) is evident
in the
zonal wind (U-component wind) anomalies averaged over 5-day
periods in the equatorial zone. The westerly wind event was first
observed in early May in the far western Pacific, and then moved
eastward during June. This event generated an eastward propagating
oceanic Kelvin
wave that eroded the cold SST anomalies that had developed in
the central and eastern Pacific during the previous two
months. |
| Since the cessation of
the cold SST anomalies in June, the equatorial Pacific region has
slowly warmed. This observed warming did not develop into an El
Niño by the end of 2003, but the SST anomalies have been
consistently warm since July in both Niño regions (map of
Niño regions). Anomalously warm SSTs have been been
measured in the Niño
3.4 region for the past 6 months, and the SST anomaly had
reached +0.56 °C (+1.01 °F) for the
December mean. The warm oceanic conditions were also present in
the sub-surface measurements from NOAA's array of moored buoys.
Warmer than normal conditions were evident in the mixed-layer
during
December across the entire Pacific basin, although the observed
ocean temperatures were well below the peak warmth observed during
the 2002-2003
El Niño event. |
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Loop
of 2003 Sub-Surface Temperatures
|
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image
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image
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The atmospheric
indices measured during the latter half of 2003 in the Pacific
region showed mixed signals regarding their response to the
observed warming in the oceanic mixed-layer. The
Southern Oscillation Index (SOI) was consistently negative
during the first 6 months of 2003, which lagged the dissipation of
the El Niño event. The SOI remained negative through much of
the year but was strongly positive in December (see the latest
SOI
graph). Deep tropical convection in the western and central
equatorial Pacific typically responds to the warm waters associated
with ENSO warm events, and this is measured by
Outgoing Longwave Radiation (OLR) across the western and
central Pacific region. OLR anomalies were strongly negative in
early 2003, in response to the warm SSTs during the El Niño.
However, they have remained positive since April, despite the more
recent warming in the equatorial Pacific Ocean observed since July
(see the latest OLR
Anomaly graph). Through much of the year, the atmospheric
signal was mixed, with the SOI reflecting the warm SST anomalies,
and the OLR remaining positive and reflecting a weak La Niña
type signature. Please link to the ENSO
Monitoring page for the latest ENSO conditions in the tropical
Pacific. |
Regional Temperatures
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Annual temperatures
were above average across most land areas. The adjacent figure
depicts warmer than average temperatures (for a 1961-1990 base
period) that were widespread across much of the contiguous United
States and Alaska, as well as most of Europe and Asia. Temperatures
in these regions were 2-5°C (3.6-9.0°F) above the 1961-1990
average. This map was created using data from the Global
Historical Climatology Network, a network of more than 7,000
land surface observing stations. The only widespread areas of
negative anomalies were across parts of the eastern U.S., coastal
areas of Australia and far western Asia where temperatures were
between 1 and 3°C (1.8-5.4°F) cooler than average. |
| Notable temperature extremes during 2003 included a severe
heatwave during summer of 2003 across Europe. Daily maximum
temperatures ranged from 30-37°C (90-99°F) across France,
Switzerland and the Mediterranean region, killing approximately
25,000 people. France had its warmest summer on record, and
according to news reports, more than 14,000 people died of
heat-related causes during the peak of the heat wave in late July
and August. In North America, extreme cold winter temperatures
resulted in an unusually high ice concentration across the Great
Lakes. More than 90 percent of lakes Superior, Erie and Huron were
frozen by March 10th, the most ice cover since February 1994.
Unseasonably cold weather affected Bangladesh, India and much of
Asia in January, leading to the deaths of more than 1,000 people.
Average minimum temperatures were as low as 2-4°C
(36-39°F), in a region where minimum temperatures are usually
12-14°C (54-57°F). In the Peruvian highlands, temperatures
dropped below -20°C (-5°F) during the Southern Hemisphere
winter month of July, which led to the reported deaths of more than
200 people. For more information on temperature extremes during
2003 see the annual report of Significant
Events |
Global Precipitation
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Global precipitation
was below the 1961-1990 average in 2003 for the third year in a
row. Drought was widespread across much of eastern Australia during
the first half of the year. India monsoon rainfall was 102 percent
above normal, bringing relief to areas that were plagued with
drought for much of 2002. Western Asia's rainfall was 80 percent
above average, alleviating long-term drought conditions. In
Zimbabwe, severe drought affected 900,000 people, one of Zimbabwe's
worst droughts in 50 years. Other drought-affected areas included
the western United States where the multi-year drought continued to
ravage the region. |
| In contrast to drought conditions, Denver, CO had it's second
biggest snowstorm on record when 31.80 inches of snow fell in
March. In February, a snowstorm hit the northeastern U.S., breaking
numerous 24-hour snowfall records. Heavy rainfall in mountainous
regions of southwest Asia's mountain region ameliorated long-term
drought conditions but caused a landslide in the village of
Kara-Taryk, Kyrgyzstan killing 38 people. In Sante Fe, Argentina
the reported worst flooding to occur since 1573 occurred in April
of 2003. Several days of heavy rainfall caused local rivers to rise
as much as 20 inches in one hour, killing 23 people and forcing the
evacuation of 45,000. By early May, flooding was so severe, Sante
Fe was characterized as an island. For more information about
precipitation extremes during 2003 see the annual report of
Significant
Events. |
Additional information on other notable weather events can be
found in the Significant
Events section of this report.
References
IPCC, 2001: Climate Change 2001: The Scientific Basis,
Contribution of Working Group I to the Third Assessment Report of
the Intergovernmental Panel of Climate Change. J.T. Houghton, Y.
Ding, D.J. Griggs, M. Noguer, P.J. vander Linden, X.Dai, K.
Maskell, and C.A. Johnson (Eds.), Cambridge University Press, 881
pp.
NOAA's National Climatic Data Center is the world's largest
active archive of weather data. The preliminary temperature and
precipitation rankings are available from the center by calling:
828-271-4800.
NOAA works closely with the academic and science communities on
climate-related research projects to increase the understanding of
El Niño and improve forecasting techniques. NOAA's Climate
Prediction Center monitors, analyzes and predicts
climate events ranging from weeks to seasons for the nation.
NOAA also operates the network of data buoys and satellites that
provide vital information about the ocean waters, and initiates
research projects to improve future climate forecasts.
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