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William M. Connolley and Stephen A. Harangozo

Abstract

In this paper, numerical weather prediction analyses from four major centers are compared—the Australian Bureau of Meteorology (ABM), the European Centre for Medium-Range Weather Forecasts (ECMWF), the U.S. National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR), and The Met. Office (UKMO). Two of the series—ECMWF reanalysis (ERA) and NCEP–NCAR reanalysis (NNR)—are “reanalyses”; that is, the data have recently been processed through a consistent, modern analysis system. The other three—ABM, ECMWF operational (EOP), and UKMO—are archived from operational analyses.

The primary focus in this paper is on the period of 1979–93, the period used for the reanalyses, and on climatology. However, ABM and NNR are also compared for the period before 1979, for which the evidence tends to favor NNR. The authors are concerned with basic variables—mean sea level pressure, height of the 500-hPa surface, and near-surface temperature—that are available from the basic analysis step, rather than more derived quantities (such as precipitation), which are available only from the forecast step.

Direct comparisons against station observations, intercomparisons of the spatial pattern of the analyses, and intercomparisons of the temporal variation indicate that ERA, EOP, and UKMO are best for sea level pressure;that UKMO and EOP are best for 500-hPa height; and that none of the analyses perform well for near-surface temperature.

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Thomas C. Peterson, William M. Connolley, and John Fleck

Climate science as we know it today did not exist in the 1960s and 1970s. The integrated enterprise embodied in the Nobel Prizewinning work of the Intergovernmental Panel on Climate Change existed then as separate threads of research pursued by isolated groups of scientists. Atmospheric chemists and modelers grappled with the measurement of changes in carbon dioxide and atmospheric gases, and the changes in climate that might result. Meanwhile, geologists and paleoclimate researchers tried to understand when Earth slipped into and out of ice ages, and why. An enduring popular myth suggests that in the 1970s the climate science community was predicting “global cooling” and an “imminent” ice age, an observation frequently used by those who would undermine what climate scientists say today about the prospect of global warming. A review of the literature suggests that, on the contrary, greenhouse warming even then dominated scientists' thinking as being one of the most important forces shaping Earth's climate on human time scales. More importantly than showing the falsehood of the myth, this review describes how scientists of the time built the foundation on which the cohesive enterprise of modern climate science now rests.

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