Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 13 7 2009 10.5194/hess-13-1307-2009 http://www.hydrol-earth-syst-sci.net/13/1307/2009/ http://www.hydrol-earth-syst-sci.net/13/1307/2009/hess-13-1307-2009.html http://www.hydrol-earth-syst-sci.net/13/1307/2009/hess-13-1307-2009.pdf 1307 1311 2009-07-24 Reply to A. G. C. A. Meesters et al.'s comment on "Biotic pump of atmospheric moisture as driver of the hydrological cycle on land" A. M. Makarieva elba@peterlink.ru V. G. Gorshkov Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg, Russia Condensation removes water vapor molecules from the gas phase and reduces the weight of the air column. This disturbs hydrostatic equilibrium and makes air circulate under the action of the recently described evaporative force. Meesters, Dolman and Bruijnzeel (2009) criticized the physical bases of the new circulation driver with a major claim that the ascending air motions induced by the evaporative force should rapidly restore the hydrostatic equilibrium and become extinguished. Here we respond that in fact these air motions sustain the disequilibrium of air pressure through the reduction of the weight of the air column via condensation that continuously occurs as the ascending moist air cools. In the traditional meteorological paradigm condensation is primarily considered in terms of the effect it has, via latent heat release, on air <i>density</i>, while its immediate effect on the <i>weight</i> of air column is not accounted for. The critique of Meesters et al. is therefore informative in highlighting the traditional lines of thought that should be re-visited to incorporate the new physical knowledge. Such an effort is arguably worthy of undertaking as the evaporative force concept bears tangible potential for solving some of the key problems that are challenging modern atmospheric science. Chown, S. L. and Gaston, K. J.: Macrophysiology for a changing world, Proc. Biol. Sci., 275, 1469–1478, 2008. Feynman, R. P., Leighton, R. B., and Sands, M.: The Feynman Lectures on Physics, Vol 1, Addison-Wesley, Reading, 1963. Folkins, I.: Convective damping of buoyancy anomalies and its effect on lapse rates in the tropical lower troposphere, Atmos. Chem. Phys., 6, 1–12, 2006. Makarieva, A. M. and Gorshkov, V. G.: Biotic pump of atmospheric moisture as driver of the hydrological cycle on land, Hydrol. Earth Syst. Sci., 11, 1013–1033, 2007. Makarieva, A. M. and Gorshkov, V. G.: Condensation-induced dynamic gas fluxes in a mixture of condensable and non-condensable gases, Phys. Lett. A, 373, 2801–2804, 2009. Makarieva, A. M., Gorshkov, V. G., and Li, B.-L.: Conservation of water cycle on land via restoration of natural closed-canopy forests: Implications for regional landscape planning, Ecol. Res., 21, 897–906, 2006. Makarieva, A. M., Gorshkov, V. G., and Li, B.-L.: On the validity of representing hurricanes as Carnot heat engine, Atmos. Chem. Phys. Discuss., 8, 17423–17437, 2008. Makarieva, A. M., Gorshkov, V. G., and Li, B.-L.: Precipitation on land versus distance from the ocean: Evidence for a forest pump of atmospheric moisture, Ecol. Complexity, doi:10.1016/j.ecocom.2008.11.004, in press, 2009. Marengo, J. A.: Characteristics and spatio-temporal variability of the Amazon River Basin Water Budget, Clim. Dynam. 24, 11–22, 2005. Meesters, A. G. C. A., Dolman, A. J., and Bruijnzeel, L. A.: Comment on "Biotic pump of atmospheric moisture as driver of the hydrological cycle on land" by A. M. Makarieva and V. G. Gorshkov, Hydrol. Earth Syst. Sci., 11, 1013–1033, 2007, Hydrol. Earth Syst. Sci., in press, 2009.\blackbox\bf will be updated by the Production Office. Riehl, H.: A model of hurricane formation, J. Appl. Phys. 21, 917–925, 1950. Sheil, D. and Murdiyarso, D.: How forests attract rain: an examination of a new hypothesis, Bioscience, 59, 341–347, 2009.