## 1. Introduction

Jaramillo et al. (2018) critiqued our theory of condensation-induced atmospheric dynamics (CIAD). CIAD results from the difference between evaporation and condensation. While most evaporation occurs at Earth’s surface, and is a slow, widely distributed process, condensation in contrast occurs within the atmospheric volume and, depending on vertical air velocity, can be orders of magnitude more rapid than evaporation. In simplified form, water vapor with partial pressure *w*. The product ^{−3} s^{−1}) gives the rate of the release of available potential energy ^{−3}) equal to the rate of generation of the kinetic energy of wind (Makarieva and Gorshkov 2009, 2010; Makarieva et al. 2013b, 2014a).

Jaramillo et al. (2018) stated that CIAD modifies the equation of vertical motion such that it violates Newton’s third law. This is incorrect: CIAD constrains the power of atmospheric circulation; it does not modify “the vertical momentum budget” nor any fundamental equations of hydrodynamics. Furthermore, Jaramillo et al.’s (2018) analysis of the equation of vertical motion is invalid.

## 2. The equation of vertical motion

*g*is the acceleration of gravity; and

*p*and density

*ρ*of dry air, water vapor, and moist air as a whole. The terms grouped in each set of parentheses are interpreted by Jaramillo et al. (2018) as “the forces on each component”—dry air and water vapor. “Internal forces”

*R*is the ideal gas constant,

*T*is temperature, and

This conclusion is not supported by evidence. First, Jaramillo et al. (2018) did not quote any equation from our works that would represent the alleged modified equation of vertical motion. Jaramillo et al. (2018) incorrectly attribute their Eq. (11), which is an adiabatic version of

The problem with this assumed derivation is that Eqs. (5) and (6) are incorrect. Separate equations of motion can be justified for such components of moist air as the gas and the condensate as they have distinct velocities (Makarieva et al. 2017), but not for the various components of a mixture of ideal gases that all move at the same velocity. In the case of Eqs. (5) and (6), the error is to assume that

Molecules of all gases adjacent to the considered unit volume of moist air collide and exchange momentum: dry air and water vapor molecules outside the volume collide with both dry air and water vapor molecules within it (Fig. 1a). The difference in the rates of these collisions above and below the volume determines the vertical pressure gradient *water vapor molecules* outside with *any molecules* within determines *all* air, and not just the water vapor, will accelerate (Fig. 1b).

Since the external forces in Eqs. (5) and (6) are incorrectly specified by Jaramillo et al. (2018), Eqs. (5) and (6) are also incorrect as equations of motion: the sum of the forces on the right-hand side of these equations, taken per unit mass, is not equal to accelerations

## 3. CIAD and potential energy

*L*(J mol

^{−1}) is the latent heat of vaporization and

^{−3}) was interpreted as a store of potential energy available for conversion to kinetic energy (Makarieva and Gorshkov 2009, 2010). An analogy is a spring compressed from an equilibrium state with length

*i*th gas with partial pressure

*M*is independent of altitude, and all gases have the same scale height

*h*[Gorshkov et al. 2012, their Eq. (15)]:

**v**and

**w**are the total and vertical air velocities. It is in this sense that the evaporative force drives winds. Accordingly, the key equation of CIAD is the equality between

**u**is the horizontal velocity (

**v**=

**w**+

**u**); see Eqs. (4), (17), and (5) of, respectively, Makarieva and Gorshkov (2009, 2010, 2011), Eq. (16) of Gorshkov et al. (2012), and Eq. (37) of Makarieva et al. (2013b). Equation (11) presumes that condensation is associated with the vertical movement and temperature gradient.

We have shown that Eq. (11) can explain and describe the observed wind and pressure profiles in hurricanes and tornadoes (Makarieva and Gorshkov 2009, 2011; Makarieva et al. 2011). When Eq. (11) is generalized to account for horizontal temperature gradients (Makarieva and Gorshkov 2010; Makarieva et al. 2014a), it can also explain the wind power in the Amazon rain forest (Makarieva et al. 2014b). The global integral of Eq. (11) produces an estimate of condensation-driven global circulation power that likewise matches observations (Makarieva et al. 2013b).

## 4. Conclusions

While Jaramillo et al.’s (2018) criticisms are unsupported, we value any interest and discussion of CIAD and its implications. As in the steady-state kinetic energy production is balanced by dissipation, CIAD by constraining atmospheric power can guide the parameterization of turbulence (which in current models is fitted to observations). Furthermore, CIAD implies that removing major terrestrial sources of water vapor, for example, through deforestation, will influence atmospheric circulation, modify ocean-to-land moisture transport, and impact the terrestrial water cycle (Makarieva and Gorshkov 2007; Makarieva et al. 2013a, 2014b).

Many observation-based studies have shown a significant impact of vegetation cover on ocean-to-land circulation and moisture import (e.g., Levermann et al. 2009; Chikoore and Jury 2010; Andrich and Imberger 2013; Poveda et al. 2014; Herzschuh et al. 2014; Levermann et al. 2016; Boers et al. 2017). The relevant discussions are controversial, since current circulation models cannot explain abrupt changes in air circulation following changes in vegetation (e.g., Levermann et al. 2016; Boos and Storelvmo 2016). If modeled turbulence could be reparameterized so as to account for CIAD, we expect the simulated atmospheric reactions to vegetation degradation/recovery to become more realistic, resolving the mismatch between models and observations.

## Acknowledgments

This work is partially supported by the University of California Agricultural Experiment Station, Australian Research Council Project DP160102107, and the CNPq/CT-Hidro–GeoClima Project Grant 404158/2013-7. We thank two anonymous referees for useful comments. Any further discussion ensuing from this exchange will be listed online (at bioticregulation.ru/ciad).

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