ESHS/HSS Annual Meeting

Weathering numerical models

• In Event: At the Fringes of Earth Science Models

English Abstract

In a “Numerical Experiment”, published in 1956, Norman Phillips presented the first general circulation model (GCM) of the atmosphere. Simulated on a computer, this numerical model could display well known large-scale atmospheric movement patterns. These promising initial results were quickly followed by the establishment of an independent laboratory exclusively dedicated to the numerical development of GCMs: the Geophysical Fluid Dynamics Laboratory (GFDL).

Phillips' "Numerical Experiment" is often regarded as the first of the now-dominating numerical climate models. In this paper, I compare Phillips' model to previous weather forecasting models and analyze the GFDL's funding application. First, I argue that interpreting Phillips' "Numerical Experiment" as the beginning of climate modeling is anachronistic. To the researchers involved, this first GCM was in continuity with the development of numerical weather forecasting. Then, I advocate that with GCM, numerical modeling of atmospheric phenomena acquired a new dimension: they could be used not only for their predictive function but also as powerful epistemic tools, in that they demonstrate how different parameters contribute to the formation and maintenance of specific large-scale atmospheric movement patterns. Finally, I present physical models of the atmosphere that were developed during the same period. These experimental setups mimicked atmospheric conditions. They consisted of a differentially heated fluid in a rotating apparatus. I show that, in many aspects, Phillips’ model echoed these physical experiments. In addition, numerical and physical modelers’ productions were often found in similar scientific environment: both groups published in the same journals, attended the same conferences, and worked in the same laboratories. I propose that it was the interaction between the two types of modelers that led to atmospheric numerical models acquiring epistemic function.

Author

• Barbara Mercier, Technische Universität Berlin