The Amazon rainforest.

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1 Water is a vital requirement for all forms of life on this planet and vegetation is no exception. It demands for a sufficient amount of soil moisture, and consequently precipitation, to sustain itself. In the case of the Amazon rainforest, 50% to 75% of the rainfall originates from its own forest evapotranspiration 1-4. The immediate danger the Amazon basin faces, due to extensive deforestation, is thus clear; the lesser vegetation, the lesser evapotranspiration and, hence, the lesser its ability to sustain itself. The Amazon rainforest.

2 A number of studies show the effects of tropical rainforest removal through the use of global climate models 5-7. An outcome of such researches indicates an apparent connection between the deforestation of the Amazon rainforest and statisticallysignificant changes in precipitation in other regions, such as North America, Europe and South Africa, subsequently called teleconnections 7,8. Teleconnections of the Amazon basin. Illustration adapted from Marengo 2.

3 The Amazon Rainforest plays thus a vital role in maintaining the fragile equilibrium of our global climate. We cannot discount the possibility that large-scale agro-industrial schemes could lead to desertification of the Colombian Amazon which, spreading across the Amazon basin, would result in climatic changes in South America and ultimately the world. Forest cover for scenarios assuming (a) that recent deforestation trends will continue and (b) the Brazilian environmental legislation is implemented through the refinement and multiplication of current experiments in frontier governance. Illustration from Soares-Filho 9.

4 Although global climate models take deforestation into account, these do not encapsulate all of the observed dynamics of tropical rainforests and thus fail in producing realistic predictions 10. Consequently, Makarieva and Gorshkov have reformulated some of the physics to fit these dynamics. The biotic pump opens a new dimension in the understanding of the hydrological cycle. Impact of deforestation as simulated by conventional models versus the Biotic Pump Theory. Data from Makarieva and Gorshkov 10.

5 The Biotic Pump Theory states that the major physical cause of moisture fluxes is not the non-uniformity of atmospheric and surface heating, but the fact that water vapour is not in aerostatic equilibrium and its partial pressure is not compensated by its weight in the atmospheric column. The resulting force, subsequently called the evaporative force, is invariably upwarddirected. The physical principle that the low-level air moves from areas with weak evaporation to areas with more intensive evaporation, where black arrows represent evaporation flux (width schematically indicates the magnitude of this flux) and empty arrows are the horizontal and ascending fluxes of moisture-laden air in the lower atmosphere. Illustration from Makarieva and Gorshkov 10.

6 The aims of this project are to: Implement and verify a conceptual model of the Biotic Pump mechanism as to verify the physical basis and parameter space of this theory. Assess possible collapsing points of the Amazon rainforest sustainability due to excessive deforestation. Assess the scarcity of data over the Amazon basin as to encourage collaboration and development of additional weather stations. Structure of the Biotic Pump Conceptual Model (BioPCM). Illustration adapted from Ahrens 13. Set up weather stations and raise local awareness onclimate change issues.

7 The implementation of the vertical distribution of water vapour in BioPCM has shown: That water vapour partial pressure is better simulated using the equation of hydrostatic equilibrium with the scaling height of saturated water vapour derived from the Clausius- Clapeyron equation 10,14 even when the air is unsaturated. Agreement is further improved using the dew-point lapse rate (DPLR) rather than the environmental lapse rate (ELR). The importance of sounding data and the scarcity of such data over the Amazon basin. Root mean squared errors (RMSE), and corresponding standard deviations (σ), between observed and simulated partial pressures over for Belem, Manaus and Natal, Brazil, where simulated partial pressures are calculated using the equation for hydrostatic equilibrium and a) the scaling height of unsaturated water vapour derived from the equation of state for ideal gases (h), b) the scaling height of saturated water vapour derived from the Clausius-Clapeyron equation (h H2O ) with a vertical profile of the ELR, c) h H2O with a vertical profile of the DPLR and d) h H2O with Earth s average observed ELR (6.49 K km -1 ).

8 Immediate following steps are: The implementation of the horizontal fluxes of water vapour in BioPCM and writing-up ofcorresponding results. Further testing of sounding equipment prototypes developed by AnaSphere. Organizing the implementation of a sounding station in Leticia, Amazonas, Colombia, in collaboration with the University of Montana, USA. Dissemination of preliminary results. The Entropika team conducting sounding experiments in collaboration with the University of Montana (UM), USA. From left to right: Angela Maldonado, Jennifer Fowler (UM), Abby Thane (UM), Thomas Lafon (OBU) and Andres Barona.

9 Glossary Aerostatic equilibrium: State of balance of motionless gases when compression due to gravity is balanced by a pressure gradient force in the opposite direction. Clausius-Clapeyron equation: Equation characterizing a discontinuous phase transition between two phases of matter. Dew-point: Temperature to which air must be cooled (at constant pressure and constant water vapour content) for saturation to occur. Dew-point lapse rate: Rate of decrease of the dew-point temperature with elevation. Environmental lapse rate: Rate of decrease of air temperature with elevation. Evapotranspiration: Sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Partial pressure: Pressure of a gas if it alone would occupy the volume of a gas mixture. References 1. Lettau, H., Lettau, K. and Molion, L. C. B. (1979). Amazonia's hydrological cycle and the role of atmospheric recycling in assessing deforestation effects. Monthly Weather Review 107 (3),pp Marengo, J. A. (2006). On the hydrological cycle of the Amazon basin: A historical review and current stateof-the-art. Revista Brasileira de Meteorologia 21 (3), pp Salati, E. (1987). The forest and the hydrological cycle. The Geophysiology of Amazonia, pp Salati, E. and Vose, P. B. (1984). Amazon basin: A system in equilibrium. Science 225 (4658), pp Clark, D., Xue, Y., Harding, R. and Valdes, P. (2001). Modeling the impact of land surface degradation on the climate of tropical North Africa. Journal of Climatology 14, pp Henderson-Sellers, A., Dickinson, R., Durbridge, T., Kennedy, P., McGuffie, K. and Pittman, A. (1993). Tropical deforestation: Modeling local- to regionalscale climate change. Journal of Geophysical Research 98, pp Werth, D. and Avissar, R. (2002). The local and global effects of Amazon deforestation. Journal of Geophysical Research 107 (D20), pp Avissar, R. and Werth, D. (2005). Global hydroclimatological teleconnections resulting from tropical deforestation. Journal of Hydrometeorology 6, pp Soares-Filho, B. S., Nepstad, D. C., Curran, L. M., Cerqueira, G. C., Garcia, R. A., Ramos, C. A., Voll, E., McDonald, A., Lefebvre, P. and Schlesinger, P. (2006). Modelling conservation in the Amazon basin. Nature 440, pp Makarieva, A. M. and Gorshkov, V. G. (2007). Biotic pump of atmospheric moisture as driver of the hydrological cycle on land. Hydrology and Earth System Sciences 11, pp Makarieva, A. M. and Gorshkov, V. G. (2009). Condensation-induced dynamic gas fluxes in a mixture of condensable and non-condensable gases. Physics Letters A 373, pp Makarieva, A. M. and Gorshkov, V. G. (IN PRESS.). Potential energy of atmospheric water vapour and the air motions induced by water vapour condensation in different spatial scales. arxiv: v Ahrens, C. D. (2009). Stability and Cloud Development. Meteorology Today: An introduction to weather, climate, and the environment. Ninth ed. Belmont, USA: Brooks/Cole, pp Landau, L. D., Akhiezer, A. I. and Lifshitz, E. M. (1967). General Physics, Mechanics and Molecular Physics. Oxford, UK: Pergamon Press. Research by Thomas Lafon with Oxford Brookes University, Oxford, UK, and in collaboration with the Centre for Ecology and Hydrology, Wallingford, UK, and Fundación Entropika, Leticia, Amazonas, Colombia. Information contact: thomaslafon@hotmail.com More information: