Modern Observations: Temperature Data and Their Interpretation

Thomas C. Peterson
NOAA’s National Climatic Data Center, Asheville, NC

The global surface temperature time series reveals that our planet has been warming over the last century and especially over the last few decades. The observing systems that produce the raw instrumental data that go into the time series have undergone a variety of changes that can introduce non-climatic biases into the data. For example, sea surface temperature observations used to be made by sticking a thermometer into a bucket of surface water hauled up on deck. Now ships make their measurements using thermometers in engine cooling water intake pipes which bring in water from several meters below the surface. Such changes have caused a great deal of effort to be expended developing approaches to remove the various non-climatic biases.

This presentation will describe the ongoing efforts to insure robust calculation of global mean surface temperature including improving international data exchange, quality control and homogeneity adjustment methodology. Analyses that evaluate how well these methods remove biases from a variety of sources, such as urban heat islands, will also be described. Lastly, no discussion of global surface temperature data would be complete without interpreting or attributing the climate change signal imbedded in the surface temperature time series. Therefore, the talk will very briefly outline some the science that supports the statement by the Nobel Prize winning Intergovernmental Panel on Climate Change’s Fourth Assessment Report that “most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas