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Journal ArticleDOI

Fog Water Collection in a Subtropical Elfin Laurel Forest of the Garajonay National Park (Canary Islands): A Combined Approach Using Artificial Fog Catchers and a Physically Based Impaction Model

01 Oct 2008-Journal of Hydrometeorology (American Meteorological Society)-Vol. 9, Iss: 5, pp 920-935
TL;DR: In this paper, the authors evaluated the potential contribution of fog water captured by needle-leafed Erica arborea L. trees in a selected watershed of the Garajonay National Park (La Gomera Island) for a 2-yr period (February 2003-January 2005).
Abstract: Fog precipitation has long been assumed as an additional water source in the relic laurel ecosystems of the Canary Islands, located at 500–1400 m MSL. However, to what extent fog water can contribute to the laurel forest water balance is not yet clear. Combining data from artificial fog catchers and a physically based impaction model, the authors evaluated the potential contribution of fog water captured by needle-leafed Erica arborea L. trees in a selected watershed of the Garajonay National Park (La Gomera Island) for a 2-yr period (February 2003–January 2005). Fog water collection was measured with artificial catchers at four micrometeorological stations placed at 1145, 1185, 1230, and 1270 m MSL. Average fog water collection was only significant at the highest measurement site (one order of magnitude greater than at lower altitudes), totaling 496 L m−2 yr−1 during the 2-yr period. The average fog water yield in the first and second annual periods ranged between 0.2–5.0 and 0.1–2.1 L m−2 day−1...
Citations
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Journal ArticleDOI
TL;DR: This unique system is composed of well-distributed clusters of conical spines and trichomes on the cactus stem; each spine contains three integrated parts that have different roles in the fog collection process according to their surface structural features.
Abstract: Multiple biological structures have demonstrated fog collection abilities, such as beetle backs with bumps and spider silks with periodic spindle-knots and joints. Many Cactaceae species live in arid environments and are extremely drought-tolerant. Here we report that one of the survival systems of the cactus Opuntia microdasys lies in its efficient fog collection system. This unique system is composed of well-distributed clusters of conical spines and trichomes on the cactus stem; each spine contains three integrated parts that have different roles in the fog collection process according to their surface structural features. The gradient of the Laplace pressure, the gradient of the surface-free energy and multi-function integration endow the cactus with an efficient fog collection system. Investigations of the structure-function relationship in this system may help us to design novel materials and devices to collect water from fog with high efficiencies.

1,051 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss some selected steps that are critical for improving success in outplanting woody plants, both under current and projected climate change conditions including: (1) Plant species selection, (2) Improved nursery techniques, and (3) Improved planting techniques.
Abstract: Reforestation efforts in dryland ecosystems frequently encounter drought and limited soil productivity, although both factors usually interact synergistically to worsen water stress for outplanted seedlings. Land degradation in drylands (e.g. desertification) usually reduces soil productivity and, especially, soil water availability. In dry sub-humid regions, forest fires constitute a major disturbance affecting ecosystem dynamics and reforestation planning. Climate change projections indicate an increase of drought and more severe fire regime in many dryland regions of the world. In this context, the main target of plantation technology development is to overcome transplant shock and likely adverse periods, and in drylands this is mostly related to water limitations. In this paper, we discuss some selected steps that we consider critical for improving success in outplanting woody plants, both under current and projected climate change conditions including: (1) Plant species selection, (2) Improved nursery techniques, and (3) Improved planting techniques. The number of plant species used in reforestation is increasing rapidly, moving from a reduced set of well-known, easy-to-grow, widely used species, to a large variety of promising native species. Available technologies allow for reintroducing native plants and recovering critical ecosystem functions for many degraded drylands. However, climate change projections introduce large uncertainties about the sustainability of current reforestation practices. To cope with these uncertainties, adaptive restoration approaches are suggested, on the basis of improved plant quality, improved techniques for optimizing rain use efficiency in plantations, and exploring native plant species, including provenances and genotypes, for their resilience to fire and water use efficiency.

120 citations


Cites background from "Fog Water Collection in a Subtropic..."

  • ...In Canary Island laurel forests, water from fog may account for 20–45 % of conventional precipitation (Ritter et al. 2008)....

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Journal ArticleDOI
TL;DR: In this article, the authors investigate the extent to which S. sabulicola relies on water supply by fog harvesting and find that fog harvest occurs mainly via stem flow with subsequent absorption by the root system and therefore represents a substantial water source for this species.

101 citations

01 Jul 2010

95 citations


Cites background from "Fog Water Collection in a Subtropic..."

  • ...a substantial amount of the annual precipitation rate at certain sites (Kämmer, 1974; Ritter et al., 2008)....

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Journal ArticleDOI
TL;DR: A review of current models for fog collection, designs, and applications of fog water harvesting is provided in this article, where the authors identify some aspects of fog harvesting requiring further research and development.
Abstract: As the world’s population and demand for fresh water increases, new water resources are needed. One commonly overlooked aspect of the water cycle is fog, which is an important part of the hydrology of coastal, high-altitude, and forested regions. Fog water harvesting is being investigated as a sustainable alternative water resource for drinking water and reforestation. Fog water harvesting involves using mesh nets to collect water as fog passes through them. The materials of these nets, along with environmental factors such as wind speed, influence the volume of water collected. In this article, a review of current models for fog collection, designs, and applications of fog water harvesting is provided. Aspects of fog water harvesting requiring further research and development are identified. In regions with frequent fog events, fog water harvesting is a sustainable drinking water resource for rural communities with low per capita water usage. However, an analysis of fog water harvesting potential for the coastal areas of northern California (USA) showed that fog yields are too small for use as domestic water in areas with higher household water demands. Fog water shows particular promise for application in reforestation. Fog water irrigation can increase growth rates and survivability of saplings in reforestation efforts in regions with frequent fog events. Using fog collectors, denuded areas once dependent on natural fog drip can be restored, benefiting local hydrology and ecosystem recovery. Improvement in fog collector designs, materials, and models to increase collection efficiency, perhaps by inclusion of ideas from natural systems, will expand the regions where fog harvesting can be applied.

90 citations

References
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Book
01 Jan 1998
TL;DR: In this paper, an updated procedure for calculating reference and crop evapotranspiration from meteorological data and crop coefficients is presented, based on the FAO Penman-Monteith method.
Abstract: (First edition: 1998, this reprint: 2004). This publication presents an updated procedure for calculating reference and crop evapotranspiration from meteorological data and crop coefficients. The procedure, first presented in FAO Irrigation and Drainage Paper No. 24, Crop water requirements, in 1977, allows estimation of the amount of water used by a crop, taking into account the effect of the climate and the crop characteristics. The publication incorporates advances in research and more accurate procedures for determining crop water use as recommended by a panel of high-level experts organised by FAO in May 1990. The first part of the guidelines includes procedures for determining reference crop evapotranspiration according to the FAO Penman-Monteith method. These are followed by updated procedures for estimating the evapotranspiration of different crops for different growth stages and ecological conditions.

21,958 citations

Journal ArticleDOI
TL;DR: In this paper, the second edition of the Second edition, the authors present a list of symbolic symbols for the field of environmental physical sciences, including the following: 1.GAS LAWS Pressure, volume and temperature Specific heats Lapse rate Water and water vapour Other gases 3. TRANSPORT LAWS General transfer equation Molecular transfer processes Diffusion coefficients Radiation laws 4. RADI ENVIRONMENT Solar radiation Terrestrial radiation Net radiation 5. MICROCLIMATOLOGY OF RADIATION (i) Interception Direct solar radiation Diffuse radiation Radiation in
Abstract: PREFACE TO THE SECOND EDITION LIST OF SYMBOLS 1. SCOPE OF ENVIRONMENTAL PHYSICS 2. GAS LAWS Pressure, volume and temperature Specific heats Lapse rate Water and water vapour Other gases 3. TRANSPORT LAWS General transfer equation Molecular transfer processes Diffusion coefficients Radiation laws 4. RADIATION ENVIRONMENT Solar radiation Terrestrial radiation Net radiation 5. MICROCLIMATOLOGY OF RADIATION (i) Interception Direct solar radiation Diffuse radiation Radiation in crop canopies 6. MICROCLIMATOLOGY OF RADIATION (ii) Absorption and reflection Radiative properties of natural materials Net radiation 7. MOMENTUM TRANSFER Boundary layers Wind profiles and drag on uniform surfaces Lodging and windthrow 8. HEAT TRANSFER Convection Non-dimensional groups Measurements of convection Conduction Insulation of animals 9. MASS TRANSFER (i) Gases and water vapour Non-dimensional groups Measurement of mass transfer Ventilation Mass transfer through pores Coats and clothing 10.MASS TRANSFER (ii) Particles Steady motion 11.STEADY STATE HEAT BALANCE (i) Water surfaces and vegetation Heat balance equation Heat balance of thermometers Heat balance of surfaces Developments from the Penman Equation 12.STEADY STATE HEAT BALANCE (ii) Animals Heat balance components The thermo-neutral diagram Specification of the environment Case studies 13.TRANSIENT HEAT BALANCE Time constant General cases Heat flow in soil 14.CROP MICROMETEOROLOGY (i) Profiles and fluxes Profiles Profile equations and stability Measurement of flux above the canopy 15.CROP MICROMETEOROLOGY (ii) Interpretation of measurements Resistance analogues Case studies: Water vapour and transpiration Carbon dioxide and growth Sulphur dioxide and pollutant fluxes to crops Transport within canopies APPENDIX BIBLIOGRAPHY REFERENCES INDEX

4,087 citations

Journal ArticleDOI
TL;DR: In this article, the terminal velocities for distilled water droplets falling through stagnant air are accurately determined using a new method employing electronic techniques, and the over-all accuracy of the massterminal-velocity measurements is better than 0.7 per cent.
Abstract: The terminal velocities for distilled water droplets falling through stagnant air are accurately determined. More than 1500 droplets of mass from 0.2 to 100,000 micrograms, embracing droplets so small that Stokes' law is obeyed up to and including droplets so large that they are mechanically unstable, were measured by a new method employing electronic techniques. An apparatus for the production of electrically charged artificial water droplets at a controllable rate is described. The over-all accuracy of the mass-terminal-velocity measurements is better than 0.7 per cent.

1,465 citations


"Fog Water Collection in a Subtropic..." refers methods in this paper

  • ...The terminal fall velocity VD (m s ) of the raindrops was then calculated from the median droplet size such that (Gunn and Kinzer 1949)...

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Book
01 Mar 2000
TL;DR: In this paper, the authors investigated the effect of the size distribution function on the performance of a single element particle capture by diffusion and interception at high Reynolds numbers and showed that the effects of the distribution function are independent of the particle size.
Abstract: 1. AEROSOL CHARACTERIZATION Parameters Determining Aerosol Behavior Particle Size Particle Concentration Size Distribution Function Moments of the Distribution Function Examples of Size Distribution Functions Chemical Composition Aerosol Dynamics: Relation to Characterization 2. PARTICLE TRANSPORT PROPERTIES Equation of Diffusion Coefficient of Diffusion Friction Coefficient Agglomerate Diffusion Coefficients Path Length of a Brownian Particle Migration in an External Force Field Electrical Migration Thermophoresis London-van der Waals Forces Boundary Condition for Particle Diffusion 3. CONVECTIVE DIFFUSION: EFFECTS OF FINITE PARTICLE DIAMETER AND EXTERNAL FORCE FIELDS Equation of Convective Diffusion Similitude Considerations for Aerosol Diffusion Concentration Boundary Layer Diffusion to Cylinders at Low Reynolds Numbers: Concentration Boundary Layer Equation Diffusion at Low Reynolds Numbers: Similitude Law for Particles of Finite Diameter Low Re Deposition: Comparison of Theory with Experiment Single Element Particle Capture by Diffusion and Interception at High Reynolds Numbers High Re Deposition: Application to Deposition on Rough Surfaces Diffusion from a Laminar Pipe Flow Diffusion from a Turbulent Pipe Flow Particle Deposition from Rising Bubbles Convective Diffusion in an External Force Field: Electrical Precipitation Thermophoresis: "Dust Free Space" 4. INERTIAL TRANSPORT AND DEPOSITION Particle-Surface Interactions: Low Speeds Particle-Surface Interactions: Rebound Particle Acceleration at Low Reynolds Numbers: Stop Distance Similitude Law for Impaction: Stokesian Particles Impaction of Stokesian Particles on Cylinders and Spheres Impaction of Non-Stokesian Particles Deposition from a Rotating Flow: Cyclone Separator Particle Eddy Diffusion Coefficient Turbulent Deposition Aerodynamic Focusing: Aerosol Beams Transition from the Diffusion to Inertial Ranges 5. LIGHT SCATTERING Scattering by Single Particles: General Considerations Scattering by Particles Small Compared to the Wavelength Scattering by Large Particles: The Extinction Paradox Scattering in the Intermediate Size Range: Mie Theory Scattering by Aerosol Clouds Scattering over the Visible Wavelength Range: Aerosol Contributions by Volume Rayleigh Scattering: Self-Similar Size Distributions Mie Scattering: Power Law Distributions Quasi-Elastic Light Scattering Specific Intensity: Equation of Radiative Transfer Equation of Radiative Transfer: Formal Solution Light Transmission Through the Atmosphere: Visibility Inelastic Scattering: Raman Effect 6. EXPERIMENTAL METHODS Sampling Microscopy Mass Concentration: Filtration Total Number Concentration: Condensation Particle Counter Total Light Scattering and Extinction Coefficients Size Distribution Function Mass and Chemical Species Distribution: The Cascade Impactor Aerosol Chemical Analysis Summary Classification of Measurment Instruments Monodisperse Aerosol Generators 7. COLLISION AND COAGULATION: COALESCING PARTICLES Introduction Collision Frequency Function Brownian Coagulation Brownian Coagulation: Dynamics of Discrete Distribution for an Intially Monodisperse Aerosol Brownian Coagulation: Effect of Particle Force Fields Effect of van der Waals Forces Effect of Coulomb Forces Collision Frequency for Laminar Shear Simultaneous Laminar Shear and Brownian Motion Turbulent Coagulation Equation of Coagulation: Continuous Distribution Function Similarity Solution: Coagulation in the Continuum Regime Similarity Solution for Brownian Coagulation Similarity Solution: Coagulation in the Free Molecule Region Time to Reach the Self-Preserving Distribution (SPD) 8. DYNAMICS OF AGGLOMERATE FORMATION AND RESTRUCTURING Agglomerate Morphology: Scaling Laws Computer Simulation of Agglomerate Formation Langevin Simulations of Agglomeration Smoluchowski Equation: Collision Kernals for Power Law Aggregates Self-Preserving Agglomerate Size Distributions Effect of Primary Particle Size on Agglomerate Growth Effect of Df on Agglomearte Growth Agglomerate Restructuring 9. THERMODYNAMICS PROPERTIES The Vapor Pressure Curve and the Supersaturated State Effects of Solutes on Vapor Pressure Vapor Pressure of a Small Particle Hygroscopic Particle-Vapor Equilibrium Charged Particle-Vapor Equilibria Solid Particle-Vapor Equilibrium Effect of Particle Size on the Equilibrium of a Heterogeneous Chemical Reaction Molecular Clusters 10. GAS-TO-PARTICLE CONVERSION Condensation by Adiabatic Expansion: The Experiments of C.T.R. Wilson Kinetics of Homogeneous Nucleation Experimental Test of Nucleation Theory Heterogeneous Condensation Growth Laws Dynamics of Growth: Continuity Relation in v Space Measurement of Growth Rates: Homogeneous Gas-Phase Reactions Simultaneous Homogeneous and Heterogeneous Condensation Effects of Turbulence on Homogeneous Nucleation 11. THE GENERAL DYNAMIC EQUATION FOR THE PARTICLE SIZE DISTRIBUTION FUNCTION General Dynamic Equation for the Discrete Distribution Function Coagulation and Nucleation as Limiting Processes in Gas-to-Particle Conversion General Dynamic Equation for the Continuous Distribution Function The Dynamic Equation for the Number Concentration N The Dynamic Equation for the Volume Fraction Simultaneous Coagulation and Diffusional Growth: Similarity Solution for Continuum Regime Simultaneous Coagulation and Growth: Experimental Results The GDE for Turbulent Flow The GDE for Turbulent Stack Plumes Coagulation and Stirred Settling Coagulation and Deposition by Convective Diffusion Continuously Stirred Tank Reactor 12. SYNTHESIS OF SUBMICRON SOLID PARTICLES: AEROSOL REACTORS Aerosol Reactors: Commercial and Pilot Scale The Collision-Coalescence Mechanism of Primary Particle Formation Extension of the Smouluchowski Equation to Colliding, Coalescing Particles Rate Equation for Particle Coalescence Solid-State Diffusion Coefficient Estimation of Average Primary Particle Size: Method of Characteristic Times Primary Particle Size: Effects of Aerosol Material Properties Particle Neck Formation Particle Crystal Structure 13. ATMOSPHERIC AEROSOL DYNAMICS Atmospheric Aerosol Size Distribution Aerosol Dynamics in Power Plant Plumes Chemical Composition of Urban Aerosols Distributions of Chemical Species with Particle Size Morphological Characteristics of the Submicron Aerosol Common Measures of Air Quality for Particulate Matter: Federal Standards Receptor Modeling: Source Apportionment Statistical Variations of Ambient Aerosol Chemical Components EACH CHAPTER ENDS WITH PROBLEMS AND REFERENCES Common Symbols Index

1,047 citations


"Fog Water Collection in a Subtropic..." refers background or methods in this paper

  • ...Tree population density was computed from Golubic (2001), as described in Ritter et al....

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  • ...Diffusion efficiency is given by (Wyslouzil et al. 1997; Friedlander 2000)...

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  • ...Here ( ) is the fog capture efficiency due to impaction with the obstacle although other fog collection mechanisms such as direct interception, Brownian diffusion, and gravitational sedimentation, are also possible (Friedlander 2000)....

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Journal ArticleDOI
TL;DR: The applicability of such results to conditions of natural rainfall has been thrown in doubt as discussed by the authors, and the results have been found to be affected by the drop-size and velocity of the artificial rains applied.
Abstract: Curiosity concerning the drop-size composition of natural rain has arisen from attempts to measure erodibility and infiltration-capacity by sprinkling small areas of land with artificial rain. The results have been found to be affected by the drop-size and velocity of the artificial rains applied, and the applicability of such results to conditions of natural rainfall has been thrown in doubt.

921 citations


"Fog Water Collection in a Subtropic..." refers methods in this paper

  • ...To carry out the correction due to inclined rainfall incident to a sloping surface, the wind-corrected rainfall intensity Rc (mm h ) was used to compute the median raindrop diameter D50 (mm) (Laws and Parsons 1943):...

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