HEMISPHERIC-ASYMMETRY OF SURFACE-TEMPERATURE ANOMALIES

In recent months there has been some controversy concerning the possib le effect of suspended sulfate aerosols on warming trends predicted to occur in response to steadily increasing greenhouse gas concentration s in the troposphere. Evidence in the recent literature both supportin g and doubting the theory that aerosols have suppressed warming in the Northern Hemisphere more than in the Southern Hemisphere has relied o n analyses of radiosonde observations covering various periods between 1958 and 1995. In this letter the UK Met Office/University of East An glia Climatic Research Unit (Parker/Jones) data sets of mean surface t emperature anomalies over land and sea for the past 140 years serve as an independent data base to test earlier reported results obtained fr om radiosonde observations. The results suggest that there is no evide nce of any systematic differences in temperature trends between the tw o hemispheres.