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Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
doi:10.5194/hessd-12-10921-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
27 Oct 2015
Review status
This discussion paper has been under review for the journal Hydrology and Earth System Sciences (HESS). The manuscript was not accepted for further review after discussion.
Experimental evidence of condensation-driven airflow
P. Bunyard1, M. Hodnett2,a, G. Poveda3, J. D. Burgos Salcedo4, and C. Peña5 1IDEASA, Universidad Sergio Arboleda, Bogotá, Colombia
2Centre for Ecology & Hydrology, Wallingford, UK
3Department of Geosciences and Environment, Universidad Nacional de Colombia, Sede Medellín, Colombia
4Corporación para la Investigación y la Innovación – CIINAS, Bogotá, Colombia
5Facultad de Matemática, Universidad Sergio Arboleda, Bogotá, Colombia
aretired
Abstract. The dominant "convection" model of atmospheric circulation is based on the premise that hot air expands and rises, to be replaced by colder air, thereby creating horizontal surface winds. A recent theory put forward by Makarieva and Gorshkov (2007, 2013) maintains that the primary motive force of atmospheric circulation derives from the intense condensation and sharp pressure reduction that is associated with regions where a high rate of evapotranspiration from natural closed-canopy forests provides the "fuel" for cloud formation. The net result of the "biotic pump" theory is that moist air flows from ocean to land, drawn in by the pressure changes associated with a high rate of condensation.

To test the physics underpinning the biotic pump theory, namely that condensation of water vapour, at a sufficiently high rate, results in an uni-directional airflow, a 5 m tall experimental apparatus was designed and built, in which a 20 m3 body of atmospheric air is enclosed inside an annular 14 m long space (a "square donut") around which it can circulate freely, allowing for rotary air flows. One vertical side of the apparatus contains some 17 m of copper refrigeration coils, which cause condensation. The apparatus contains a series of sensors measuring temperature, humidity and barometric pressure every five seconds, and air flow every second.

The laws of Newtonian physics are used in calculating the rate of condensation inside the apparatus. The results of more than one hundred experiments show a highly significant correlation, with r2 > 0.9, of airflow and the rate of condensation. The rotary air flows created appear to be consistent both in direction and velocity with the biotic pump hypothesis, the critical factor being the rate change in the partial pressure of water vapour in the enclosed body of atmospheric air. Air density changes, in terms of kinetic energy, are found to be orders of magnitude smaller than the kinetic energy of partial pressure change.

The consistency of the laboratory experiments, in confirming the physics of the biotic pump, has profound implications for current mathematical climate models, not just in terms of predicting the consequences of widespread deforestation, but also for better understanding the atmospheric processes which lead to air mass convection.


Citation: Bunyard, P., Hodnett, M., Poveda, G., Burgos Salcedo, J. D., and Peña, C.: Experimental evidence of condensation-driven airflow, Hydrol. Earth Syst. Sci. Discuss., 12, 10921-10974, doi:10.5194/hessd-12-10921-2015, 2015.
P. Bunyard et al.
Interactive discussionStatus: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version      Supplement - Supplement
 
RC C4650: 'More information needed on dynamic models', Anonymous Referee #1, 05 Nov 2015 Printer-friendly Version 
AC C4742: 'general reply to reviewer's comments', Peter Bunyard, 08 Nov 2015 Printer-friendly Version 
RC C4900: 'review', Anonymous Referee #1, 17 Nov 2015 Printer-friendly Version 
AC C5474: 'experiments with added heating', Peter Bunyard, 08 Dec 2015 Printer-friendly Version 
RC C4825: 'HESSD 12, 10921 - 10974', Anonymous Referee #2, 11 Nov 2015 Printer-friendly Version 
AC C4846: 'substantiation of Biotic Pump Theory', Peter Bunyard, 13 Nov 2015 Printer-friendly Version 
RC C4958: 'Reply', Anonymous Referee #2, 19 Nov 2015 Printer-friendly Version Supplement 
AC C5484: 'experiments with added heating', Peter Bunyard, 08 Dec 2015 Printer-friendly Version 
 
RC C4945: 'Review', Axel Kleidon, 18 Nov 2015 Printer-friendly Version 
AC C5338: 'Latent heat considerations', Peter Bunyard, 02 Dec 2015 Printer-friendly Version 
RC C5342: 'Not at all convincing', Axel Kleidon, 02 Dec 2015 Printer-friendly Version 
RC C5369: 'Response Reviewer #2', Anonymous Referee #2, 03 Dec 2015 Printer-friendly Version Supplement 
AC C5392: 'humidity', Peter Bunyard, 04 Dec 2015 Printer-friendly Version 
SC C5489: 'experiments with added heating', Peter Bunyard, 08 Dec 2015 Printer-friendly Version 
 
AC C5331: 'experiments with added heating', Peter Bunyard, 02 Dec 2015 Printer-friendly Version 
 
AC C5479: 'experiments with added heating', Peter Bunyard, 08 Dec 2015 Printer-friendly Version 
RC C5494: 'Ignorance does not help', Axel Kleidon, 08 Dec 2015 Printer-friendly Version 
 
RC C5500: 'About the new experiments and their interpretation, etcetera', Anonymous Referee #1, 08 Dec 2015 Printer-friendly Version 
 
AC C5640: 'condensation airflow against gravity', Peter Bunyard, 15 Dec 2015 Printer-friendly Version 
RC C5800: 'reply to latest experiments', Anonymous Referee #1, 22 Dec 2015 Printer-friendly Version 
 
AC C5805: 'Condensation and counter flow', Peter Bunyard, 23 Dec 2015 Printer-friendly Version 
 
AC C5892: 'upwards airflow from condensation', Peter Bunyard, 04 Jan 2016 Printer-friendly Version 
P. Bunyard et al.
P. Bunyard et al.

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Short summary
Through physical experiments on 20 cubic metres of enclosed air in a structure consisting of two 5 m tall interconnected columns, water vapour condensation is seen to lead to uni-directional horizontal airflows. The findings support the physics underlying the controversial biotic pump theory. The conclusion is that large-scale deforestation will, through diminished cloud formation, have a devastating impact on intra-continental rain patterns, even leading to desertification.
Through physical experiments on 20 cubic metres of enclosed air in a structure consisting of two...
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