Estimates of the climatological land surface energy and water balance derived from maximum convective power

Kleidon, Axel; Renner, Maik; Porada, Philipp

doi:10.5194/hess-18-2201-2014

Cited by 51 publications

(53 citation statements)

References 45 publications

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“…While McDonnell et al (2007) considered optimization in hydrology as a visionary concept some years ago, the rapidly increasing number of publications related to several topics in hydrology (e.g., Kleidon and Schymanski, 2008;Kleidon and Renner, 2013;Kleidon et al, , 2014…”

Section: Introductionmentioning

confidence: 99%

Transferring the concept of minimum energy dissipation from river networks to subsurface flow patterns

Hergarten

Winkler

Birk

2014

Hydrol. Earth Syst. Sci.

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Abstract. Principles of optimality provide an interesting alternative to modeling hydrological processes in detail on small scales and have received growing interest in the last years. Inspired by the more than 20 years old concept of minimum energy dissipation in river networks, we present a corresponding theory for subsurface flow in order to obtain a better understanding of preferential flow patterns in the subsurface. The concept describes flow patterns which are optimal in the sense of minimizing the total energy dissipation at a given recharge under the constraint of a given total porosity. Results are illustrated using two examples: two-dimensional flow towards a spring with a radial symmetric distribution of the porosity and dendritic flow patterns. The latter are found to be similar to river networks in their structure and, as a main result, the model predicts a power-law distribution of the spring discharges. In combination with two data sets from the Austrian Alps, this result is used for validating the model. Both data sets reveal power-law-distributed spring discharges with similar scaling exponents. These are, however, slightly larger than the exponent predicted by the model. As a further result, the distributions of the residence times strongly differ between homogeneous porous media and optimized flow patterns, while the mean residence times are similar in both cases.

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Section: Introductionmentioning

confidence: 99%

Transferring the concept of minimum energy dissipation from river networks to subsurface flow patterns

Hergarten

Winkler

Birk

2014

Hydrol. Earth Syst. Sci.

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“…A moist atmosphere differs from a dry atmosphere by manifesting distinct processes that can generate air motion. One, the release of latent heat in the ascending air, has received much attention in studies of the atmospheric heat engine (e.g., Goody, 2003;Pauluis, 2011;Kleidon et al, 2014;Kieu, 2015).…”

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confidence: 99%

Quantifying the global atmospheric power budget

Makarieva

Gorshkov

Nefiodov

et al. 2016

Preprint

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Starting from the definition of mechanical work for an ideal gas, we present a novel derivation linking global wind power to measurable atmospheric parameters. The resulting expression distinguishes three components: the kinetic power associated with horizontal motion, the kinetic power associated with vertical motion and the gravitational power of precipitation. We discuss the caveats associated with integration of material derivatives in the presence of phase transitions and how these affect published analyses of global atmospheric power. Using the MERRA database for the years 2009–2015 (three hourly data on the 1.25° x 1.25° grid at 42 pressure levels) we estimate total atmospheric power at 3.1 W m−2 and kinetic power at 2.6 W m−2. The difference between the two (0.5 W m−2) is about half the independently estimated gravitational power of precipitation (1 W m−2). We explain how this discrepancy arises from the limited spatial and temporal resolution of the database. Our analysis suggests that the total atmospheric power calculated with a spatial resolution of the order of one kilometer (thus capturing the small moist convective eddies) should be around 5 W m−2. We discuss the physical constraints on global atmospheric power and how considering the dynamic effects of water vapor condensation offers new opportunities.

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“…In particular, it relates closely to a general hypothesis of maximum entropy production (MEP; e.g. Ozawa et al, 2003;Martyushev and Seleznev, 2006;Kleidon et al, 2010;Kleidon, 2016), which has been applied rather successfully in the past to describe atmospheric dynamics (Paltridge, 1975;Ozawa and Ohmura, 1997;Lorenz et al, 2001;Kleidon et al, 2006) and to the mean climatological surface energy balance partitioning on land (Kleidon et al, 2014). As maximising the power of a heat engine results in maximum frictional dissipation, this is almost the same as maximising the associated entropy production of this process.…”

Section: Turbulent Fluxes Determined From Maximum Powermentioning

confidence: 99%

“…2. The model formulation largely follows previous studies (Kleidon and Renner, 2013a, b;Kleidon et al, 2014Kleidon et al, , 2015. The main modifications here relate to the representation of heat storage changes and a formulation of terrestrial radiation based on the grey atmosphere approximation (as in Kleidon, 2016).…”

Section: Model Descriptionmentioning

confidence: 99%

An explanation for the different climate sensitivities of land and ocean surfaces based on the diurnal cycle

Kleidon

Renner

2017

Earth Syst. Dynam.

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Abstract. Observations and climate model simulations consistently show a higher climate sensitivity of land surfaces compared to ocean surfaces. Here we show that this difference in temperature sensitivity can be explained by the different means by which the diurnal variation in solar radiation is buffered. While ocean surfaces buffer the diurnal variations by heat storage changes below the surface, land surfaces buffer it mostly by heat storage changes above the surface in the lower atmosphere that are reflected in the diurnal growth of a convective boundary layer. Storage changes below the surface allow the ocean surface-atmosphere system to maintain turbulent fluxes over day and night, while the land surface-atmosphere system maintains turbulent fluxes only during the daytime hours, when the surface is heated by absorption of solar radiation. This shorter duration of turbulent fluxes on land results in a greater sensitivity of the land surface-atmosphere system to changes in the greenhouse forcing because nighttime temperatures are shaped by radiative exchange only, which are more sensitive to changes in greenhouse forcing. We use a simple, analytic energy balance model of the surface-atmosphere system in which turbulent fluxes are constrained by the maximum power limit to estimate the effects of these different means to buffer the diurnal cycle on the resulting temperature sensitivities. The model predicts that land surfaces have a 50 % greater climate sensitivity than ocean surfaces, and that the nighttime temperatures on land increase about twice as much as daytime temperatures because of the absence of turbulent fluxes at night. Both predictions compare very well with observations and CMIP5 climate model simulations. Hence, the greater climate sensitivity of land surfaces can be explained by its buffering of diurnal variations in solar radiation in the lower atmosphere.

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Estimates of the climatological land surface energy and water balance derived from maximum convective power

Cited by 51 publications

References 45 publications

Transferring the concept of minimum energy dissipation from river networks to subsurface flow patterns

Transferring the concept of minimum energy dissipation from river networks to subsurface flow patterns

Quantifying the global atmospheric power budget

An explanation for the different climate sensitivities of land and ocean surfaces based on the diurnal cycle

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