Gorshkov V.G., Makarieva A.M. (2006) Biotic pump of atmospheric moisture,
its links to global atmospheric circulation and implications for
conservation of the terrestrial water cycle. Preprint No. 2655,
Petersburg Nuclear Physics Institute, Gatchina, Russia, 47 pp.
PDF (840 Kb).
Based on the analysis of the non-equilibrium vertical distribution of
atmospheric water vapor, a physical principle is formulated according to
which the low-level air moves from areas with weak evaporation to areas
with more intensive evaporation. Air motion is supported by the
difference in the evaporation forces in the considered area. The
introduced evaporation force is upward directed; it arises due to the
fact that the vertical distribution of the condensable water vapor in
the atmosphere deviates strongly from the hydrostatic equilibrium, the
effect caused by the observed vertical lapse rate of air temperature.
Evaporation force is the cause of the observed horizontal pressure
gradient forces, exceeding them by more than two orders of magnitude. It
explains the existence of deserts, monsoons and trade winds. Due to the
high leaf area index, natural forests maintain high transpiration
fluxes, which support ascending air motion over the forest and "suck in"
moist air from the ocean, which is the essence of the biotic pump of
atmospheric moisture. In the result, the gravitational runoff water
losses from the optimally moistened forest soil can be fully compensated
by the biotically enhanced precipitation at any distance from the ocean.
In the absence of the biotic pump, precipitation over non-forested
territories declines exponentially with distance from the ocean, with
the established e-folding lengths of the order of several hundred
Related publications: Makarieva, Gorshkov, Pujol (2003) ACPD
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