William E. Reifsnyder

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

The proposed model synthesizes profiles of temperature, humidity and evaporation in a canopy of leaves from meteorological conditions at canopy top, from the temperature and humidity at the soil surface, from a leaf dimension, from the vertical distribution of leaf area and stomatal resistance, and from observations or extinction coefficients for ventilation and radiation within the canopy under steady-state conditions. The exchange of sensible and latent heat in a canopy stratum is required to be equal to the absorption of radiation by the leaves in that stratum. Further, the difference between strata in their potential for sensible and latent heat exchange is related both to leaf temperature and to the fluxes and diffusive resistances between the leaves. Leaf temperatures, evaporation and sensible heat exchange, and air temperatures within the canopy that meet these requirements were calculated by successive approximation. The microclimate and evaporation of a red clover and of a barley canopy were simulated, and changes in evaporation from a canopy following moderate changes in stomatal resistance were explained by the model.