2020/11/12 by M Leggett, Leggett, Mark, David A. Ball +2
Computer Science · Earth and Planetary Sciences · Environmental Science · Physics and Astronomy · #Atmospheric and Oceanic Physics (physics.ao-ph) #Computational Physics and Python Applications #Earth Systems and Cosmic Evolution #FOS: Physical sciences #Science and Climate Studies #Scientific Research and Discoveries
paper · pdf · doi:10.48550/arxiv.2011.06708
openalex publication_date 2020/11/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
There is evidence that a natural control system influences global atmospheric\nsurface temperature (Leggett and Ball, 2020). The present paper sets up and\ntests a hypothesis concerning the physical makeup of the sequential elements of\nthe control system and its outcomes. The final outcome the control system\ninfluences is defined as global atmospheric surface temperature. The terms used\nfor the control system element types in the hypothesis are, in sequence,\nleading element, controller and actuator. Actuators are hypothesised to affect\nin turn the final outcome either directly or via penultimate outcomes. The\nexistence of the control system is evidenced by demonstration of statistically\nsignificant one way Granger causality across each step of the hypothesised\ncontrol system sequence. Evidence is presented that the leading element of the\ncontrol system, represented by the Normalized Difference Vegetation Index, is\nthe global biosphere. The biosphere as a control system has previously been\nreferred to as Gaia (Lovelock and Margulis, 1974). A fourth (second derivative)\nterm is found to enhance the Proportional, Integral and Derivative process\nterms of the control system shown in Leggett and Ball (2020). The main\nactuators of the control system found are shown to be wind speed and cloud\ncover. Cloud cover is shown to influence the final outcome, global surface\ntemperature, directly. It and wind speed also influence the penultimate\noutcomes found, those of enhanced ocean heat uptake and enhanced outgoing\nlongwave radiation. These together lead to control system output to the final\noutcome, global atmospheric temperature. Overall, evidence for the activity of\nthe control system is present across many major physical dimensions of the\nglobal atmosphere.\n