State of the Climate
Global Analysis
December 2001

National Oceanic and Atmospheric Administration

National Climatic Data Center

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Global Highlights:

*Global average land and ocean temperature was tenth warmest for December
Lower tropospheric temperatures were above average during December
Temperatures in the lower stratosphere were cooler than average
During December, above average precipitation was most notable across the eastern Mediterranean region and parts of Brazil with below average precipitation across the eastern U.S and most of western and southern Europe

Introduction

Using a 1992-2001 base period as shown in the adjacent blended temperature product of satellite and in-situ data, anomalously cold temperatures during December in the Northern Hemisphere were closely correlated to the location of upper level troughs of low pressure. Dominant troughs of low pressure (depicted by negative 500 millibar height anomalies) were centered across eastern Europe and southern Alaska. Temperature anomalies calculated from in-situ station data using a 1961-1990 base period also show the cooler than average temperatures in these regions with warmer than average temperatures observed over most of North America, the Middle East and the African Sahel region.

Click Here for the Global Blended Temperature in December 2001

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Temperature

A slow evolution toward El Niño conditions continued during December, as the global land and ocean temperature was the tenth warmest in the 1880-2000 record and was 0.36°C (0.65°F) above the long-term average (0.22°C / 0.40°F above the 1961-1990 mean)
Temperatures averaged across ocean areas were third warmest on record, or 0.48°C (0.86°F) above the long-term December mean

Click Here for the Global Temp Anomalies in December 2001

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Click Here for the Tropical Temperature Anomalies in December 2001

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Based on data available at the time of this report, land temperatures in the tropical regions (20°N-20°S) were warmest on record for December, or 0.99°C (1.78°F) above the 1880-2000 mean

Precipitation

Much of Europe was relatively dry, with only southeastern Europe and the eastern Mediterranean region experiencing wetter than average weather
Dry conditions persisted in the eastern U.S., southeast Canada and northern Argentina
Above average precipitation fell in parts of Brazil and southeast China

Click Here for the Global Precip Anomalies in December 2001

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Microwave Sounding Unit Data

Click Here for the Lower Tropospheric Temperature time series

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December temperatures in the lowest 8km (5 miles) of the troposphere were 0.14°C (0.25°F) above average, with similar temperature anomalies across the Northern and Southern Hemisphere

Click Here for the Lower Stratospheric Temperature time series

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December temperatures were below average in the lower stratosphere, with a departure of -0.30°C (-0.54°F)
This was the 9th consecutive December with below average stratospheric temperatures

Lower 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.

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For additional details on precipitation and temperatures in December see the Global Regional page .
*Based on preliminary data available at the time of this report.

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.