Note: Intro -- Title Page -- Copyright Page -- Preface -- Table of Contents -- List of Contributors -- 1 A Climatology of UV Radiation, 1979- 2000, 65S -65N -- 1.1 Introduction -- 1.2 Method -- 1.3 Results -- 1.3.1 Satellite-Derived UV Climatologies -- 1.3.2 Comparison with Ground-Based Measurements -- 1.3.3 Discussion of Uncertanties -- 1.4 Conclusions -- References -- 2 Balancing the Risks and Benefits of Ultraviolet Radiation -- 2.1 Introduction -- 2.2 Long Term Changes in UVEry -- 2.3 Geographical Variability in UVEry -- 2.4 Peak UV -- 2.4.1 Peak UV Index -- 2.4.2 Peak UV Daily Dose -- 2.5 Comparing Weighting Functions for Erythema and Vitamin D -- 2.6 Seasonal and Diurnal Variation of UVEry and UVVitD -- 2.7 Global Climatologies of UVEry and UVVitD -- 2.8 Relationship Between UVVitD and UVEry -- 2.9 Production of Vitamin D from Sunlight -- 2.10 Calculation of Optimal Times for Exposure to Sunlight -- 2.11 An Inconsistency -- 2.12 Conclusions -- References -- 3 Climatology of Ultraviolet Radiation at High Latitudes Derived from Measurements of the National Science Foundation's Ultraviolet Spectral Irradiance Monitoring Network -- 3.1 Introduction -- 3.2 Data Analysis -- 3.2.1 Data -- 3.2.2 Establishment of Climatologies -- 3.2.3 Estimates of Historical UV Indices -- 3.3 UV Index Climatology -- 3.3.1 South Pole -- 3.3.2 McMurdo Station -- 3.3.3 Palmer Station -- 3.3.4 Ushuaia -- 3.3.5 San Diego -- 3.3.6 Barrow -- 3.4 Climatology of UV-A Irradiance -- 3.5 Comparison of Radiation Levels at Network Sites -- 3.6 Conclusions and Outlook -- References -- 4 UV Solar Radiation in Polar Regions: Consequences for the Environment and Human Health -- 4.1 Introduction -- 4.2 Networks and Databanks -- 4.3 Impact of Solar UV on the Environment -- 4.3.1 Effect of the Environment on Solar UV -- 4.4 Impact of Solar UV on Human Health. , 4.4.1 Information and Protection Programs -- 4.4.2 Dosimetry, UV Modeling, and Instruments -- 4.5 Concluding Remarks -- References -- 5 Changes in Ultraviolet and Visible Solar Irradiance 1979 to 2008 -- 5.1 Introduction -- 5.2 Instrumentation -- 5.3 Detection of Long-Term Change -- 5.3.1 Radiation Amplification Factor -- 5.3.2 Different Definitions of RAF -- 5.3.3 Estimating UV Trends: Discussion -- 5.3.4 Reduction of UV Irradiance by Clouds and Aerosols -- 5.3.5 Stokes Derivation of CT=(1-R) / (1-RG) -- 5.3.6 UV Absorption -- 5.3.7 Estimating Zonal Average UV Change -- 5.3.8 Estimating UV Trends: Satellites -- 5.3.9 Estimating UV Trends: Ground-Based -- 5.4 UV in the Polar Regions -- 5.5 Human Exposure to UV -- 5.6 UV Index and Units -- 5.7 Action Spectra and Irradiance Trends -- 5.8 UV Summary -- Appendix 5.1 Calculating RAF(ø) -- References -- 6 The Brewer Spectrophotometer -- 6.1 Introduction -- 6.2 History -- 6.3 The Instrument -- 6.3.1 The Fore-Optics -- 6.3.2 The Spectrometer -- 6.3.3 The Photomultiplier Housing -- 6.3.4 Support Electronics -- 6.3.5 The Control Computer -- 6.4 Corrections Applied to Data -- 6.4.1 Dark Count -- 6.4.2 Dead Time -- 6.4.3 Stray Light -- 6.4.4 Temperature Response -- 6.4.5 Neutral Density Filters -- 6.4.6 Cosine Response -- 6.4.7 Internal Polarization -- 6.5 Measurement of Total Ozone -- 6.5.1 Measurement Technique -- 6.5.2 Calibration -- 6.6 Measurement of Spectral UV Radiation -- 6.7 Measurement of Other Atmospheric Variables -- 6.7.1 Vertical Profile of Ozone -- 6.7.2 Atmospheric SO2 -- 6.7.3 Atmospheric NO2 -- 6.7.4 Aerosol Optical Depth -- 6.7.5 Effective Temperature of Atmospheric Ozone -- 6.8 The Brewer Spectrophotometer as a Powerful Research Tool -- 6.9 Summary -- References -- 7 Techniques for Solar Dosimetry in Different Environments -- 7.1 Introduction -- 7.2 UV Dosimetry and Minimization Strategies. , 7.3 Miniaturization of Polysulphone Dosimeters -- 7.4 Measurements on Plants -- 7.5 Long-Term UV Dosimeters -- 7.6 Vitamin D Effective UV Dosimetry -- 7.7 Discussion and Conclusions -- References -- 8 An Ultraviolet Radiation Monitoring and Research Program for Agriculture -- 8.1 Introduction -- 8.2 Introduction to the USDA UVMRP (Purpose and History) -- 8.3 Monitoring Network -- 8.3.1 Sites and Coverage -- 8.3.2 Data Products Provided by UVMRP -- 8.4 Data Collection and Processing -- 8.4.1 UV-MFRSR Data Processing -- 8.4.1.1 Dark Current Bias Removal -- 8.4.1.2 Cosine Correction -- 8.4.1.3 Out-of-Band Correction -- 8.4.2 Erythemally Weighted UV Irradiance -- 8.4.2.1 Angular (Cosine) Response of the UVB-1 Pyranometer -- 8.4.2.2 UVB-1 Spectral Response and Influence of Columnar Ozone -- 8.4.3 Langley Analysis -- 8.4.4 Data Processing for Other Measurements -- 8.5 Derived Products -- 8.5.1 Optical Depth -- 8.5.1.1 Instantaneous Optical Depth -- 8.5.1.2 Average Optical Depth -- 8.5.2 Daily Column Ozone -- 8.5.3 Synthetic Spectrum Data -- 8.6 Database Design and Website Interface -- 8.6.1 The Data -- 8.7 UVMRP's Role in UV-B Agricultural Effects Studies -- 8.7.1 Mississippi State University -- 8.7.2 Purdue University -- 8.7.3 Utah State University -- 8.7.4 University of Maryland -- 8.7.5 Washington State University -- 8.7.6 University of Illinois - Chicago -- 8.7.7 Highlights of Other Collaborations -- 8.8 Modeling of Agricultural Sustainability -- 8.9 Future Considerations -- 8.10 Summary -- References -- 9 Radiative Transfer in the Coupled Atmosphere-Snow-Ice-Ocean (CASIO) System: Review of Modeling Capabilities -- 9.1 Introduction -- 9.2 Radiative Transfer Modeling -- 9.2.1 Sun-Earth Geometry -- 9.2.2 Spectrum of Solar Radiation -- 9.2.3 Atmospheric Vertical Structure -- 9.2.4 Light Interaction with Absorbing and Scattering Media. , 9.2.4.1 Absorption and Scattering by Atmospheric Molecules and Pure Water -- 9.2.4.2 Absorption and Scattering by Particles -- 9.2.4.3 Optical Properties of the Ocean -- 9.2.4.4 Definitions of Irradiance and Radiance -- 9.2.4.5 Absorption, Scattering, and Extinction by Molecules and Particles -- 9.2.5 Equation of Radiative Transfer -- 9.2.6 Surface Reflection and Transmission -- 9.2.7 Radiative Transfer in a Coupled Atmosphere-Snow-Ice-Ocean (CASIO) System -- 9.3 Sample Applications of the Theory -- 9.3.1 Comparison of Modeled Irradiances in CAO Systems -- 9.3.2 Measured and Modeled Radiation Fields in Sea Ice -- 9.3.3 Radiation Trapping in Sea Ice -- 9.3.4 Impact of Ozone Depletion on Primary Productivity -- 9.4 Discussion and Conclusions -- References -- 10 Comparative Analysis of UV-B Exposure Between Nimbus 7/TOMS Satellite Estimates and Ground-Based Measurements -- 10.1 Introduction -- 10.2 Materials and Methods -- 10.2.1 USDA UV-B Dataset -- 10.2.2 TOMS Dataset -- 10.2.3 UV Index -- 10.2.4 Comparative Analysis -- 10.3 Results and Discussion -- 10.3.1 UV-I Daily Change Analysis -- 10.3.2 Analysis of UV-I Variability -- 10.3.3 UV-I Spatial Analysis -- 10.4 Conclusions -- References -- 11 Ultraviolet Radiation and Its Interaction with Air Pollution -- 11.1 Introduction -- 11.1.1 Factors Affecting UV Flux at the Earth's Surface -- 11.1.1.1 Solar Zenith Angle -- 11.1.1.2 Stratospheric Ozone -- 11.1.1.3 Cloud Cover -- 11.1.1.4 Atmospheric Density -- 11.1.1.5 Air Pollution (Gases and Aerosols) -- 11.2 Optics of the Atmosphere -- 11.2.1 Scattering -- 11.2.2 Absorption -- 11.2.3 Emission -- 11.2.4 Atmospheric Optical Depth -- 11.2.5 Single Scatter Albedo -- 11.2.6 Asymmetry Factor -- 11.2.7 Angstrom's Exponent -- 11.3 Models and Measurements -- 11.4 Summary -- References. , 12 Urban Forest Influences on Exposure to UV Radiation and Potential Consequences for Human Health -- 12.1 Introduction -- 12.2 Effects of Solar UV on Human Health and Epidemiology -- 12.2.1 Sunburn -- 12.2.2 Skin Types -- 12.2.3 Immune Function -- 12.2.4 Skin Cancers -- 12.2.4.1 Non-Melanoma Skin Cancers -- 12.2.4.2 Melanoma -- 12.2.5 Eye Diseases -- 12.2.6 Sunscreen Effectiveness -- 12.2.7 Positive Impacts -- 12.2.7.1 Vitamin D -- 12.2.7.2 Apparent Anti-Cancer Benefits of UV -- 12.3 UV Climatology -- 12.3.1 Ozone Trends -- 12.4 Urban Structural Influences -- 12.4.1 Sky Radiance and Diffuse Fraction -- 12.4.2 UV Reflectivity -- 12.4.3 Tree and Building Influences on UV -- 12.4.3.1 Measurements -- 12.4.3.2 Models of Tree Influences on UV-B Irradiance -- 12.4.4 Human Exposure -- 12.5 Public Health Information -- 12.6 Conclusions -- References -- 13 Solar UV-B Radiation and Global Dimming: Effects on Plant Growth and UV-Shielding -- 13.1 Introduction -- 13.1.1 Global Dimming and UV-B: Potential Effects on Plants -- 13.1.2 Assessing Global Dimming and UV-B Effects on Plant Growth -- 13.2 Methods -- 13.2.1 Field Site -- 13.2.1.1 Experimental Plots -- 13.2.2 Structural and Biomass Measurements -- 13.2.3 UV-A Epidermal Transmittance Measurements -- 13.2.4 Solar UV and PAR Irradiance -- 13.2.5 Statistical Analyses -- 13.3 Results -- 13.3.1 UV-A Epidermal Transmittance -- 13.3.2 Dimming Effects on Biomass and Structure -- 13.4 Discussion -- 13.4.1 Global Dimming and UV-B Effects on Leaf Optical Properties -- 13.4.2 Global Dimming and UV-B Effects on Productivity -- 13.4.3 Ecological Implications -- 13.4.3.1 UV Exclusion Studies -- 13.5 Concluding Remarks -- References -- 14 Effects of Ultraviolet-B Radiation and Its Interactions with Climate Change Factors on Agricultural Crop Growth and Yield -- 14.1 Introduction. , 14.2 Abiotic Stress Factors and Crop Yield.