From:http://www.eurekalert.org/bysubject/atmospheric.php

New Haven, Conn. -– The effect of the sun's heat on weather balloons largely accounts for a data discrepancy that has long contributed to a dispute over the existence of global warming, according to a report by scientists at Yale University and the National Oceanic and Atmospheric Administration (NOAA).

The report, to be published in the journal Science, says that direct heat of the sun on temperature probes of the weather balloon (radiosonde) probably explains the discrepancy between reports showing that atmospheric temperatures have been unchanged since the 1970's, while temperatures at the Earth's surface are rising.

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Co-authors on the paper were Cathryn Meyer at Yale and John Lanzante at the NOAA/ Geophysical Fluid Dynamics Laboratory at Princeton. The research was funded by the NOAA Climate and Global Change Program and the National Science Foundation.

Citation: Science Express: published on line (11 August 2005)