Ultraviolet Radiation

Specific Effects of UVB Radiation on Plants

Ultraviolet Leaf Plants

Plants are highly sensitive to UV-B radiation because of their sessile nature. In plants, UV-B radiation damages cell membranes and all organelles within the cell, including the chloroplasts, mitochondria, and deoxyribonucleic acid (DNA) within the nucleus. Damage to these cell organelles directly or indirectly affects basic plant metabolic processes, such as photosynthesis, respiration, growth, and reproduction. Consequently, UV-B damage harms crop yield and quality. An overview of various...

Calculation of Optimal Times for Exposure to Sunlight

The optimal time for exposure to sunlight that is needed to receive adequate UV for vitamin D production, but without inducing erythema, depends strongly on latitude and season. Here we develop algorithms for calculating the time in terms of the widely used UVI. We can calculate the time taken (tE in minutes) to induce skin damage (one minimum erythemal dose) using where the factor 4000 60 accounts for the conversions from UVEry to UVI and seconds to minutes UVI is the UV Index ( 40 x UVEry,...

Sky Radiance and Diffuse Fraction

It is well known that the atmosphere scatters shorter wavelengths of solar energy much more than longer wavelengths, and that the scattering increases with SZA (Iqbal, 1983). Usually, more than half of the UV-B irradiance arriving on earth is from diffuse radiation from the sky. The greater fraction of radiance from the sky has profound implications for the amount of UV-B irradiance in urban ecosystems. Not only the sky radiance fraction, but also the distribution of sky radiance, is important...

Impact of Solar UV on Human Health

Vein Oscillation The Eye

The potential consequences of global climatic change (GCC) with regard to human health have recently been the subject of numerous reviews (e.g., Leaf, 1989 Longstreth, 1991 Epstein, 1998 Longstreth, 1999). For the most part, the possibility of increased negative effects could only occur when the incidence of disease is linked to the tropics or other warm weather regions. However, it is also clear that in most locations, GCC will only affect the risk of disease if the disease already exists at...

Depth of Light Penetration into Leaf Tissues

360nm Wavelength

Light attenuation in pecan leaves at four wavelengths including UV-B, UV-A, blue light, and red light into leaf tissues is illustrated in Fig. 18.5. The depths of the light penetration into the leaf tissues are presented in Fig. 18.6. Pecan leaf epidermis strongly attenuated 310 nm UV-B, 98 of which was absorbed within the first 10 m of the 15 m-thick upper epidermal tissue (Figs. 18.5 and 18.6). High UV-B attenuation by the epidermal layer means low epidermal transmittance to UV-B. Figure 18.4...

Strategies for Protection against UVB Radiation

Plants have evolved through several mechanisms by which they protect themselves from the damaging effects of UV-B radiation (Table 14.3). Table 14.3 Protective mechanisms against damage by UV-B radiation in plants. Adapted with permission from Prasad et al. (2003b) DNA repair photo-reactivation enzymes (photolyase) excision repair by removing damaged part of DNA bypass damaged DNA and fill gaps later from sister duplex. Increase reflectance to avoid entry of UV-B radiation through cuticle wax,...

References

Alvarez-Madrigal M and Perez-Peraza J (2005) Analysis of the evolution of the Antarctic ozone hole size. J. Geophys. Res. 110, D02107, D0I 10.1029 2004JD004944 Anav A, Moriconi ML, Giannoccolo S, and Di Menno M (1996) Field measurements of global UV-B radiation a comparison between a broad-band radiometer and a Brewer spectrophotometer. Il Nuovo Cimento C(4), Vol. 14, July - August, pp. 505 - 516 Anav A, Rafanelli C, Di Menno I, and Di Menno M (2004) An algorithm for irradiance and effective...

Networks and Databanks

Does Snow Australia

An increased distribution of Arctic stations has been encouraged since the Arctic Conference met in Stockholm, Sweden in 1956, in preparation for the International Geophysical Year (IGY) of 1957. Moreover the sensitivity of instruments should be increased so that measurements could be made using moonlight, a standard method of measuring the ozone content of surface air should be developed. , . the establishment of an aerological and actinometric station on the Greenland ice cap was strongly...

Data Collection and Processing

Two data loggers are installed at each site to collect and transfer the direct measurements from the instruments referred to in Table 8.1. One data logger is used to collect the data every 15 seconds from the VIS-MFRSR, UVB-1 pyranometer, temperature humidity sensors, and the downward looking LI-COR 210SA photometer. The other is for the UV-MFRSR, PAR Quantum sensor, and barometer (and UV-A radiometer where applicable) that are sampled every 20 seconds. The difference between the sampling...

Langley Analysis

While the laboratory calibrations and characterizations of the UV-MFRSR instruments were routinely performed, an alternative technique that has been used for many decades in various applications is the Langley plot method (Shaw, 1982 Thomason et al., 1983 Wilson and Forgan, 1995 Slusser et al., 2000). The Langley plot is used to provide more frequent calibrations of both the UV and VIS MFRSRs. The Langley method is based on the Beer-Lambert law, which describes the attenuation of the sun's...

Database Design and Website Interface

Day Detox Diet Plan

The primary objective of the UVMRP database and web design is to provide a user-friendly interface for an end user to search, view, and download data and related descriptions via the Internet. The interface was designed with the client server paradigm. To prevent loss of data, backups are made with the use of tape, CD, and DVD, some of which are stored off site. The database containing the aforementioned measurements and derived data is implemented using the open source MySQL (DuBois, 2005)....

Summary

As previously shown in this chapter, the main constituent of air pollution that affects the transmission of UV to the earth's surface is aerosols. While three gases exhibit strong UV absorption characteristics, their concentrations and path-lengths in the troposphere, and primarily the planetary boundary layer, are both insufficient to produce significantly reduced UV levels at the surface. The physical, chemical and optical properties were studied, and the results strongly indicate that for...

Global Climatologies of UVEry and UVyitD

Global Distribution Rays

Global UV climatologies (Lee-Taylor and Madronich, 2007), which were calculated with the TUV1 radiative transfer model (Madronich and Flocke, 1995), were used to directly compare vitamin D weighted UV and erythemally weighted UV. In both cases, the weighting functions are as adopted by the CIE, extending to 400 nm in the case of UVEry, (McKinlay and Diffey, 1987), and to 330 nm in the case of UVVitD (Bouillon et al., 2006). If the truncated version of the vitamin D action spectrum had been...

Estimating UV Trends Satellites

Carrying Capacity

Global estimates of surface UV irradiance Fx as a function of latitude, longitude, and wavelength A have been calculated from satellite measurements of atmospheric backscattered UV radiances and the small amount reflected from the surface. The long-term precision and stability of a satellite instrument's in-flight calibration, especially the single-channel radiances used to estimate cloud transmission and reflectivity, make it very useful for estimating trends in F . In the absence of a widely...

The Concentration of Leaf UVB Absorbing Compounds

The inter-specific comparison of the total UV-B absorbing compound concentration per unit of leaf area (A280 nm-32o nm cm , assessed by integrating the absorbance values from 280 nm - 320 nm at 1 nm intervals) in the mature leaves is presented in Fig. 18.8. Large variations exist among the species. These UV-B absorbing compounds possess strong absorbance to the UV radiation (Qi et al., 2002 Qi et al., 2003b, c). It is possible that those species with the strong epidermal UV-B screening...

Effect of the Environment on Solar UV

As described above, environmental effects resulting from UV radiation exposure do exist however, several effects are also produced by the environmental components on the solar UV flux during its passage through the atmosphere. The presence of numerous substances, components (e.g., NO2, SO2), and aerosol particles due to fire, air pollution, dust, etc. (Fig. 4.9), modifies UV diffusion and scattering, creating measurement, sampling, and modeling problems. Figure 4.9 Atmospheric component...

Global Dimming and UVB Effects on Productivity

The lack of a significant growth response under reduced PAR is not totally unexpected in the high light environment of Mauna Kea where clear sky ambient PAR levels can routinely exceed 2,200 pmol m s . Light saturation would be expected for many of the leaves of the experimental plants even in early stages of canopy development. Furthermore, reductions in total available PAR have little effect in the nearly linear portion of the photosynthetic light response curve often observed for C3...

Crop Response to Multiple Abiotic Stress Factors

In natural habitats, plants are routinely subjected to a combination of abiotic factors. Under climate change scenarios, plants will be exposed to CO2, UV-B radiation, temperature, and water stress simultaneously and their performance can be assessed only when grown under these multiple abiotic stress conditions. Many recent studies suggest that temperature and precipitation changes in future decades will modify, and often limit, the direct effect of CO2 enrichment on plants (Easterling et al.,...

Abiotic Stress Tolerance and Cultivar Screening Tools

There is a large variation in tolerance or susceptibility to abiotic stresses, particularly to different climate change factors including UV-B radiation (Reddy et al., 2005 Singh et al., 2008a), high temperature stress (Craufurd et al., 2003 Prasad et al., 2006b Ristic et al., 2008), and water stress (Foulkes et al., 2002 Upadhyaya, 2005 Bakheit, 2008 Singh, 2008). This variation can provide an opportunity for genetic improvement of plant species through either traditional plant breeding...

Concluding Remarks

Increased UV-B radiation and its interaction with other climate change factors, such as temperature, water stress, and elevated CO2, can influence various physiological, growth, and yield traits of plants. In addition to direct effects on crop plants, these factors can also influence the interaction of plants with biotic factors (particularly with insect pests and plant pathogens). A comprehensive understanding of these interactions will be critical for evaluating the impact of climate change...

Summary and Conclusions

Essex and Williams 82 cultivars respond differently to UV exposure. Ultraviolet-exposed Williams 82 exhibited greater gs after the initial exposure response of reduced gs compared to the control plants that did not correspond with changes in E. Essex initially showed an increase in gs and E with UV exposure which then decreased after one day of UV exposure, or 8 kJ m-2 -12 kJ m-2 UV-Bbe exposure. The exposure of Essex and Williams to UV radiation showed no affect on photosynthesis (A or PS II...

Future Considerations

Climate Resolution Scope Statement

The USDA UVMRP is constantly reviewing its research goals and evaluating the needs expressed by the stakeholders in USDA research. Although fiscal years 2007, 2008 and 2009 saw budget reductions, the activities at UVMRP are ongoing in a manner as to consistently respond to the needs of the agricultural research community in the best possible manner. With an eye toward the future, UVMRP also collaborates with developers of UV products from satellite observations. While satellite platforms have a...

Ecological Implications

The body of evidence to date indicates that changes in UV effects on plants are often relatively subtle, but these small changes may have important ecological implications, particularly by secondary or indirect effects (Caldwell et al., 2007). The small changes in leaf optical properties and secondary chemistry, and minimal differences in productivity under simulated global dimming and UV-B reduction found in our study, are consistent with this perspective. Changes in the quantity of UV...

Atmospheric Vertical Structure

The stratified vertical structure of the bulk properties of an atmosphere is a consequence of hydrostatic balance. For an atmosphere in a state of rest, the pressure, , must support the weight of the fluid above it. By equating pressure forces and gravitational forces, one finds that dp -gpdz where g is the acceleration due to gravity, p is the air density, and dp is the differential change in pressure over the small height interval dz. Combining this equation with the ideal gas law p Mp RT Mn...

Measurement Technique

The standard algorithm used for determining total ozone with the Brewer instrument is a DOAS technique using radiation measured at four of the operational UV wavelengths, (As shown in Fig. 6.3) 310.1 nm (A 2), 313.5 nm (A 3), 316.8 nm (A 4), and 320.0 nm (A 5). Bandpasses for the slits are approximately triangular in shape (Grobner et al., 1998) with a full-width-half intensity (FWHI) of about 0.6 nm (Kerr, 2002). The DOAS method for measuring total ozone is based on the following equation...

Assessing Global Dimming and UVB Effects on Plant Growth

Ultraviolet Plant Growth

To provide some insight into the effects of global dimming on plant growth, the 372 TRENDS in Ecololgy & Evolution Figure 13.1 Idealized changes in diffuse and direct beam radiation reaching the Earth as a function of atmospheric transparency (reprinted from Roderick 2006). Solid lines represent standard atmospheric conditions dotted lines show the immediate effect of the Mt. Pinatubo volcanic eruption in June 1991 TRENDS in Ecololgy & Evolution Figure 13.1 Idealized changes in diffuse...

Radiative Transfer in a Coupled Atmosphere SnowIce Ocean Casio System

Solar irradiance levels play a key role for energy exchange and primary production in marine polar environments. Because the ocean is typically covered by sea ice and snow for several months of the year, theoretical and experimental knowledge of radiation levels at various depths in the snow, ice, and ocean is essential. The photosynthetically active radiation (PAR, 400 nm < A < 700 nm) drives the pelagic primary production in general, and the amount of PAR reaching the bottom of the sea...

Comparison of Modeled Irradiances in CAO Systems

Gjerstad et al. (2003) undertook a study aimed at comparing two distinctly different methods of solving the radiative transfer equation for coupled atmosphere-ocean systems. One of these methods was the deterministic discrete-ordinate method (Stamnes et al., 1988 2000), extended to apply to two adjacent slabs with different indices of refraction, such as a coupled atmosphere-ocean (CAO) system (Jin and Stamnes, 1994). The other method was the Monte Carlo (MC) approach, in which the trajectories...

Based Measurements

Wei Gao1, Zhiqiang Gao1,2, and Ni-Bin Chang3 1USDA UV-B Monitoring and Research Program, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, USA E-mail wgao uvb.nrel.colostate.edu E-mail zgao uvb.nrel.colostate.edu 2 Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China Department of Civil and Environmental Engineering, University of Central Florida, Orlando, FL 32816, USA E-mail nchang mail.ucf.edu Abstract...

Stratospheric Ozone

The one main absorbing parameter that must be kept constant if the effects of air pollution are being determined is the known interaction of the UV with the stratospheric ozone. The UV absorbed in this layer is the predominant factor affecting the transmission to the earth's surface. Statistical correlations of surface measured UV with variations in this layer of ozone correlate well above the r 0.90 level. The importance of ozone as a regulator of UV stems from strong absorption...

Impact of Solar UV on the Environment

Depletion Solar Radiation

The most important effect of solar UV on the environment is its photochemical interaction with oxygen, producing ozone, a GHG (greenhouse gas). The photochemistry of ozone behaves in different ways on the biosphere, depending on its height from the ground. The behavior of ozone at ground level demonstrates itself by its damaging effects on both human health (through inhaled air), and on vegetation. Because it is a major source of atmospheric oxidants, it regulates atmospheric composition and...

Models of Tree Influences on UVB Irradiance

Traditional methods for modeling solar irradiance below tree canopies have been applied to modeling tree influences on UV. Examples include (1) use of Beer's law with knowledge of the leaf area index (LAI) for relatively uniform forest Figure 12.4 The irradiances in Fig. 12.3 for Lauder, New Zealand on the summer solstice from McKenzie and Liley (Chapter 12, this volume) weighted for erythema (grey) and pre-vitamin D production (black) in the open (thick lines) and in tree shade (thin lines)...

UVB Absorbing Compounds

In the 2004 field and greenhouse experiments, 4 leaf discs (1.0 cm ) were excised from the same leaf samples used for the gs measurements described above (n 6). Leaf discs were frozen in liquid nitrogen and stored in - 80 C for one week. Ultraviolet-B absorbing pigments were extracted with 5 mL of a mixture of methanol water HCl solution (79 20 1 v v) at 90 C for 90 minutes until the leaf discs were completely bleached. The extract was centrifuged at 2,500 rpm for 5 minutes. The absorbance (per...

Assessment of DNA Damage as a Tool to Measure UVB Tolerance in Soybean Lines Differing in Foliar Flavonoid Composition

Pope, Betsy M. Sutherland , Paula V. Bennett , James E. Blum3, Ann E. Stapleton4, and Dennis C. Gitz III5 1 Department of Plant Science and Landscape Architecture, 2122 Plant Sciences Building University of Maryland, College Park, MD 20742, USA E-mail jsull umd.edu 2 Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000, USA E-mail bms bnl.gov 3 Department of Mathematics and Statistics University of North Carolina at Wilmington, Wilmington, NC...

An Ultraviolet Radiation Monitoring and Research Program for Agriculture

Davis1, Roger Tree1, James R. Slusser1, and Daniel Schmoldt 1 United States Department of Agriculture UV-B Monitoring and Research Program Natural Resource Ecology Laboratory Colorado State University, Fort Collins, CO, USA E-mail wgao uvb.nrel.colostate.edu 2 United States Department of Agriculture Cooperative State Research, Education, and Extension Service Washington, DC, USA E-mail dschmoldt csrees.usda.gov Abstract The United States Department of Agriculture (USDA)...

Introduction to the Usda Uvmrp Purpose and History

The beginnings of the USDA UVMRP stem from a series of USDA sponsored workshops, held for the purpose of determining the type of response that might be necessary to address the potential threat of UV radiation to US agriculture (Gibson 1991, 1992 Science and Policy Associates, 1992 O'Hara and O'Hara, 1993). Workshop participants, representing various universities, research institutions, and governmental agencies, recommended that the USDA establish a monitoring network to support research for...

Introduction

The bulk of the earth's atmosphere (99 by mass) consists of molecular nitrogen and oxygen, which are homonuclear, diatomic molecules that absorb little radiation at wavelengths in the UV and visible spectral ranges. Trace amounts of polyatomic molecules including ozone are responsible for atmospheric absorption. In recent years, ozone loss has been tied to the release of man-made trace gases, mainly chlorofluorocarbons used in the refrigeration industry and as propellants in spray cans. Because...

Urban Forest Influences on Exposure to UV Radiation and Potential Consequences for Human Health

USDA Forest Service Northeastern Research Station, c o SUNY ESF, 5 Moon Library, Syracuse, NY 13210, USA E-mail gheisler fs.fed.us Abstract This chapter explores the literature on ultraviolet (UV) irradiance in urban ecosystems with respect to the likely effects on human health. The focus was the question of whether the health effects of UV radiation should be included in the planning of landscape elements such as trees and shading structures, especially for high use pedestrian areas and school...

Air Pollution Gases and Aerosols

So2 Absorption

Wide varieties of pollutants are emitted to the atmosphere each year by the tons. The Environmental Protection Agency (EPA) has chosen to classify them in two broad categories based on their respective origination points. 1. Primary Pollutants are those classified as being emitted directly from sources and not undergoing any chemical or physical transformation. An example would be the carbon monoxide emitted through the automobile exhaust. Such gases are called non-reactive since they generally...

Reduction of UV Irradiance by Clouds and Aerosols

A measured daily cycle of UV reaching the surface will show large UV irradiance reductions from clear-sky conditions as clouds pass over a site while blocking the view of the sun. These reductions are frequently in excess of those caused by measured ozone changes from climatological values for wavelengths longer than 305 nm. In general, the effect of clouds and aerosols reduces the UV and VIS amounts at all wavelengths reaching the earth's surface. When using satellite data to estimate the...

Light Interaction with Absorbing and Scattering Media

Pure Water Absorption Coefficient

The absorption coefficient a(A), the scattering coefficient a(A), and the scattering phase functionp(A, 0), can be expressed as The subscript i is used to denote the various radiatively-active components, i.e., air molecules, aerosols, and liquid water and ice cloud particles in the atmosphere ice crystals and impurities in the snow brine pockets and air bubbles in the ice pure water mixed with air bubbles, chlorophyll, inorganic particles, and yellow substance in the ocean. Here A is the...

Stomatal Conductance Measurements

In the 2004 greenhouse study, stomatal conductance (gs) measurements were performed on the center leaflet adaxial surface of the highest (youngest) fully-expanded leaf on six seedlings (n 6). Leaves were oriented to maximize solar irradiance and allowed to acclimize to the radiation level until measurements stabilized (approximately 5 - 7 minutes). In 2004, measurements were made with a closed chamber steady-state porometer (LI-600, Li-Cor Inc., NE, USA) after 1, 3, 6, 12 and 18 hours of UV...

Instrumentation

Instrumentation for measuring solar radiation reaching the ground falls into a few main classes, which have been described at length in specialized literature and reports. The earliest reliable device for quantitative measurements of solar radiation was a pyranometer (Kerr et al., 1967), which converted the sun's photon energy into heat and then into a voltage or current proportional to the energy-weighted integrated solar photon flux (Fig. 5.1(a)). Pyranometers are still deployed at many...

TOMS Dataset

Uvb Radiation Map

In contrast to the ground-based point measurements, satellite data may provide us with global coverage at a moderate resolution by standard sensors that have been observing UV from space for more than 20 years. The EP TOMS dataset can be used for monitoring long-term trends in total column ozone as well as the seasonal Figure 10.1 Map of the 37 USDA ground stations, 4 of which are circled for statistical analysis Figure 10.1 Map of the 37 USDA ground stations, 4 of which are circled for...

Crop Response to Temperature

The inferences from global circulation model simulations indicate that earth's mean surface air temperature warming for a doubling of atmospheric CO2 is expected to increase by 2 C - 4.5 C (IPCC, 2007). Additionally, it is projected that heat waves will be more intense, more frequent and longer lasting in future warmer climates (Meehl and Tebaldi, 2004). Daily minimum temperatures (nighttime temperature) are projected to increase faster than daily maximum temperature (daytime), leading to...

UV Exposure Regimes Greenhouse studies

The greenhouse UV-B treatment was based on the exposures found in the conterminous United States. Analysis of the probability of having four hours in a day with an upper 5 daily exposure of 8 kJ m UV-Bbe (based on the action spectrum of Caldwell, 1971) occurs approximately 5 of the days in June and July (Grant and Slusser, 2002). During the early part of June, the soybean crops are in early vegetative stages. A 3-day sequence of such exposure levels occurs approximately 1 of the time (Grant and...

The Fore Optics

A 45 fused quartz prism is located at the head of the fore-optics tube and reflects incoming radiation (by total internal reflection) at right angles along the horizontal optical path of the instrument. The zenith prism plays an important role in selecting the appropriate source of radiation for lamp tests, sky measurements, direct sun or moon measurements, or UV spectral measurements. The prism rotates about the optical axis of the fore-optics so that radiation originating from zenith angles...

Long Term UV Dosimeters

One of the main dosimetric materials for UV exposures has been the polymer polysulphone, which was first employed in the 1970s by Davis et al. (1976a). Despite its immense usefulness, the polysulphone dosimeter is restricted as it is only capable of measuring solar exposures approximately less than ten hours during a clear summer day at a subtropical location before reaching the maximum optical saturation point. Furthermore, the uncertainty of polysulphone increases to 30 for a AA33o between...

Tree and Building Influences on UV 12431 Measurements

Along with protective clothing and sunscreen use, seeking shade is a primary means recommended by public health agencies to avoid excess exposure to UV radiation (Environmental Protection Agency, 1995 Parisi and Kimlin, 1999 Saraiya et al., 2004). However, tree effects on UV may differ significantly depending on the view of the sky and to some extent, the trees species. Ultraviolet shadows generally differ substantially from the shadows of visible light (Heisler et al., 2003 a) with UV shadows...

Estimating UV Trends Discussion

Satellite observations of UV and VIS irradiance can be used to distinguish regional and global changes in derived atmospheric properties (e.g., ozone, sulfur dioxide, reflectivity, aerosol distribution, nitrogen dioxide, UV-irradiance) in contrast to purely local observations from ground-based instruments. The estimates are based on a single well-calibrated instrument that is used over extended periods (Herman et al., 1991 Herman et al., 1996). For example, the + 52 side scanning Nimbus-7 TOMS...

Climatology of UV Radiation 1979 2000 65S65N

Julia Lee-Taylor1, Sasha Madronich1, Christopher Fischer1, and Bernhard Mayer 1 National Center for Atmospheric Research, Boulder, Colorado, USA 2 Deutsches Zentrum fur Luft- und Raumfahrt, Oberpfaffenhofen, Germany Abstract Solar ultraviolet (UV) radiation reaching earth's surface is of interest because of its role in the induction of various biological and chemical processes, including skin cancer. We present climatological distributions of monthly mean surface-level UV radiation, calculated...

UV Dosimetry and Minimization Strategies

UV radiation incident on the earth's surface is comprised of both a direct component and a diffuse component. The combination of the diffuse and direct UV is termed the global UV. As the direct component is incident directly from the sun, it is easier to minimize by simply blocking its path. However, the diffuse UV component is incident from all directions due to atmospheric and environmental scattering and can constitute a significant proportion of the UV exposure to the human body. The...

Erythemally Weighted UV Irradiance

One of the data types most frequently requested from UVMRP is a compilation of erythemally weighted irradiance over a specified geographic region and time period. The UVMRP employs YES UVB-1 pyranometers to measure the Commission Internationale de l'Eclairage (CIE) weighted erythemal irradiances (McKinlay and Diffey, 1987) at each climatological site. Initially, the UVB-1 pyranometers were calibrated and characterized annually by the instrument manufacturer. Comparisons between collocated...

Relationship Between UVyitD and UVEry

The relationship between UVVitD and UVEry, as deduced from several years of spectral UV data from Lauder, New Zealand, is shown in Fig. 2.12. At first impression, the plot in the upper panel seems to indicate a close proportionality between the two quantities, with UVVitD being approximately 2 x UVEry (for standard normalization). However, at lower values, which are characteristic of the situation throughout winter months, this proportionality breaks down. For the truncated version of the...

Different Definitions of RAF

An alternate power-law form for estimating action spectrum weighted irradiance change is commonly used for large changes in ozone amount, which empirically matches data quite well (Booth and Madronich, 1994 Blumthaler et al., 1995). This form is given in Eq. (5.3). where A and A are two values of ozone that correspond to two values of irradiance, F1 and F2, respectively. The RAF( ) is an empirically selected set of constants to match Eq. (5.3) to observed data. For small changes in A equation...

Production of Vitamin D from Sunlight

While there is considerable uncertainty regarding the wavelength dependence for vitamin D production, it has been suggested that there is insufficient vitamin D produced in the winter poleward of about 40 (Webb et al., 1988).1 Based on that work, we may take an upper limit threshold for insufficient vitamin D production as the daily available dose at the latitude of Boston, 42 N. This threshold is about 0.7 kJ m per day (see Fig. 2.8). Under the same conditions, erythemally weighted UV dose is...

UV in the Polar Regions

The expansion of the Antarctic polar vortex during the 1990s, both in spatial and temporal extent into early summer, has increased the frequency of elevated UV-B episodes over sub-Antarctic populated areas (Rousseaux et al., 1999). These episodes are no longer just small pockets of ozone depleted stratospheric air coming from the break-up of the polar vortex, but include occasional excursions of the polar vortex edge over Ushuaia, Argentina and Punta Arenas, Chile. This occurred 44 times in the...

Data Products Provided by UVMRP

The USDA UVMRP provides a wide variety of products to the broader scientific community. Although the primary stakeholders of UVMRP are focused on agricultural applications, many users of the data access the products via the web page or by special request for use in human health research, atmospheric science studies, industrial coating testing and analysis, defense contractor work, and for a few proprietary applications. The data provided by UVMRP may be divided into measurement data and derived...

Positive Impacts

It has long been recognized that some diseases are alleviated by moderate UV-B exposure (van der Leun and de Gruijl, 1993), though the benefits of vitamin D from sun exposure were generally not emphasized. UV Radiation in Global Climate Change Measurements, Modeling and Effects on Ecosystems 12.2.7.1 Vitamin D Although more literature is now available regarding the benefits of UV in the production of vitamin D and the consequent reductions in non-cutaneous cancers, sorting out the risks and...

Radiation Amplification Factor

An alternate method for the estimation of long-term changes in UV-B irradiance can be devised by combining measured ozone values with radiative transfer calculations. These calculations can be simplified for estimating irradiance change by neglecting scattering effects. For clear-sky, constant cloud, and constant aerosol conditions, changes in monochromatic UV-B irradiance dF show a well-defined inverse relation with changes in the amount of ozone d in the atmosphere based on laboratory...

Measurements Modeling and Effects on Ecosystems

Global Climate Change Measurements, Modeling and Effects on Ecosystems ( )(Schmoldt, D. L), ( )K S(Slusser, J. R.) t A ffi , 2009.11 I. n. m- m. mm - m - - - m - H ffl mCIPft (2009)M 153863 m tt S A WAM A M tt & 010-62770175 ft 010-62786544 010-62776969, c-service tup.tsinghua.edu.cn 010-62772015, zhiliang tup.tsinghua.edu.cn 153 x 235 EPf 35.25 797 2009 11 MM 1 m EP& 2009 11 1 EpflJ Ifcfti lf fflf MffiM.f Mfef 010-62770177 3103 025568-01 Natural Resource Ecology Laboratory Colorado State...

List of Contributors

11 1 2 Julia Lee-Taylor , Sasha Madronich , Christopher Fischer , and Bernhard Mayer National Center for Atmospheric Research, Boulder, Colorado, USA Deutsches Zentrum f r Luft- und Raumfahrt, Oberpfaffenhofen, Germany Richard L. McKenzie and J Ben Liley National Institute of Water and Atmospheric Research (NIWA), Lauder, Central Otago, New Zealand 9352 NIWA Lauder, Private Bag 50061 Omakau, Central Otago 9352, New Zealand E-mail r.mckenzie niwa.co.nz E-mail b.liley niwa.co.nz Germar Bernhard,...

Crop Response to Drought

Climate change is predicted to bring regional-scale precipitation extremes, causing both flooding and drought in certain areas (Giorgi et al., 1998). Most model simulations predict decreased precipitation by the end of the 21st century in subtropical regions (IPCC, 2007). Increased precipitation extremes are also likely in major agricultural production areas, e.g., southern and eastern Asia, eastern Australia, and northern Europe (Christensen et al., 2007). The 2003 summer drought in Europe...

Stomatal Conductance

Stomatal Conductance

The 2004 gs measurements of the control plant leaves at V2 stage were significantly higher than that of the R2 through R4 stages in 2007 (Fig. 16.2(a)), but were comparable to the measurements of the control plant leaves at V2 stage in 2008 (Fig. 16.2(c)). The gs of Essex leaves at VC stage consistently increased with time into the experiment while that of the other stages showed no trend over the experimental time period (Fig. 16.2(c)). The Williams 82 and Essex control plant gs measurements...

Cosine Response

Traditionally, the measurement of surface radiation has been made to quantify the downward flux incident on a horizontal surface. This is used for studies involving the radiative transfer of flux through the atmosphere and at the earth's surface. The downward flux is the total radiation integrated over the celestial hemisphere weighted with the cosine of the zenith angle. Most radiation monitoring instruments, including the Brewer, are designed to replicate the cosine response to incident...

Miniaturization of Polysulphone Dosimeters

Miniaturized polysulphone dosimeters were employed to take high density measurements on living and manikin subjects under various environmental conditions to facilitate detailed mapping of the erythemal UV exposure to unprotected skin (Downs and Parisi, 2007 2008). These dosimeters are cost-effective and provide accurate short-term UV exposure measurements for personal and environmental applications that may require a large number of dosimeters. Such applications may include UV exposure...

Uvmfrsr Data Processing

The UV-MFRSR uses independent interference filter-photodiode detectors and an automated rotating shadow band to measure the total horizontal and diffuse horizontal UV solar irradiance at seven wavelengths concurrently Michalsky et al., 1988 Harrison et al., 1994 . Direct normal irradiance is determined within the data logger by subtracting the diffuse from the total signal, followed by a correction for imperfect cosine response. The UV-MFRSR instruments provide synchronized measurements of...

Atmospheric Optical Depth

The optical depth (r) is the summation of extinction (scattering and absorption) by all the gases and pollutants of the atmosphere where nj is the altitude dependent concentration of the ( j ) gases and particles that attenuate radiation, each with an effective cross section (scattering and absorption) o). Retrievals of the optical depth from ground-based sensors generally employ two methods (1) the Langley-plot slope method, and (2) measurements of absolute spectrally-resolved solar flux with...

Global Dimming and UVB Potential Effects on Plants

Reductions in shortwave radiation with increased atmospheric aerosols and other particulates are well established. This reduction of total shortwave radiation also coincides with an increase in the diffuse portion of the shortwave radiation (Black et al., 2006 Roderick, 2006) as aerosols and particulates increase the scatter of direct beam radiation (Fig. 13.1). Surface ultraviolet radiation (UV < 400 nm) levels are also influenced by atmospheric aerosols and other pollutants, both causing...

UVA Epidermal Transmittance

Epidermal transmittance for UV-A for fava beans grown in a high UV environment on Mauna Kea was found to be significantly affected by both the dimming treatment and UV-B screening (Table 13.1 Fig. 13.3). On average, measured transmittances increased 6.6 with a 13 reduction in PAR (+ UVB full sun vs. + UVB reduced sun). Screening of UV-B fUrther increased epidermal Table 13.1 Summary of 2-way ANOVA of the global dimming and UV-B reduction experiment conducted with fava bean at the Mauna Kea, HI,...

Global Dimming and UVB Effects on Leaf Optical Properties

Small increases of epidermal transmittance for UV in fava bean leaves were found under the 13 reduction in PAR and with UV-B exclusion. These results are consistent with increases in leaf UV-absorbing compounds with increased UV-B exposure (Mazza et al., 2000 Searles et al., 2001 Coleman and Day, 2004). Over a wide range of solar radiation regimes, we found that only small differences in epidermal transmittance occurred over large ranges of PAR (500 - 2,000 mol m s ), and that this relationship...

Characteristics of UVB Radiation Tolerance in Broadleaf Trees in Southern USA

Heisler , Wei Gao , Thomas C. Vogelmann , and Shuju Bai 1 Urban Forestry Program, P.O. Box 11288, Southern University Baton Rouge, LA 70813, USA E-mail yadong_qi subr.edu 2 USDA Forest Service Northeastern Research Station, c o SUNY ESF, 5 Moon Library, Syracuse, NY 13210, USA E-mail gheisler fs.fed.us 3 USDA UV-B Radiation Monitoring Program, and Senior Research Scientist, Natural Resource Ecology Laboratory, Colorado State University Fort Collins, CO 80523-1499, USA...

Estimating Zonal Average UV Change

Since changes in cloud, plus aerosol, reflectivity have been small over the 1979 to 2008 period, except in some local regions (Herman et al., 2009b), the zonal average change in UVB radiation is dominated by changes in ozone amounts. For this purpose, the changes can be estimated from Eq. (5.1) or (5.3), or including the observed LER change term as in Eq. (5.2). The ozone data set is based on a combination of satellite data from Nimbus-7 TOMS, the SBUV-2 series of satellite data, EP TOMS, and...

Measurements on Plants

UVB radiation can be damaging to plant physiology and plant growth (Teramura and Sullivan, 1994), but solar visible radiation is important to the photosynthesis process in plants. This radiation (400 nm - 700 nm) is referred to as photo-synthetically active radiation (PAR). Both PAR and UV radiation within the solar spectrum have to be accounted for as the plant response to UVB depends on solar visible radiation exposure (Caldwell et al., 1995). PAR can have a direct influence on plant response...

Methodology 1821 Plant Materials

Leaves of the selected southern broadleaf tree species (Table 18.1, column 1) were collected from individual trees growing in Baton Rouge, Louisiana, USA, during two growing seasons from April to October in 2000 and in 2001. Leaf samples were collected each month from the sun portions of four unshaded individuals per species at the terminal 20 cm - 50 cm of a branch or stem, and were placed in humidified plastic bags in an insulated box for transporting to the laboratory. The experiment was a...

Measuring the Light Penetration and Distribution within Leaf Tissues

Penetration Expression Gif

The depth of light penetration into leaves and spectral distribution within leaf tissues were measured using a fiber optic microprobe system (Fig. 18.1) (Qi et al., 2003a), which was modified based on Vogelmann and Bjorn (1984) and Vogelmann et al. (1991). The microprobes were fabricated in Dr. T. C. Vogelmann's lab, using 150 im diameter (OD) multimode step-index fibers made of fused silica (Polymicro Technologies, Phoenix, AZ, USA). The fibers were heated and drawn to a tip diameter of around...

Atmospheric NO2

Surface UV radiation is also affected by atmospheric NO2, which absorbs at UV wavelengths. Atmospheric NO2 typically absorbs a small percentage of global radiation at the earth's surface. Sources of atmospheric NO2 are both manmade and natural. Pollution from sources such as automobiles and aircraft account for NO2 near the ground, in addition to regions in the troposphere and lower stratosphere. NO2 occurs naturally in the stratosphere and plays an important role in the photochemistry of...

The Brewer Spectrophotometer as a Powerful Research Tool

The original development of the Brewer spectrophotometer and subsequent upgrades have provided users with pre-programmed routines for making a suite of the most common types of operational measurements, set-up, tests, and calibrations. Preprogrammed routine measurements include global UV scans, Umkehr measurements, measurements of total ozone, SO2, and NO2 using direct sun, zenith sky, or global radiation. Operational tests include standard lamp and mercury lamp tests to set wavelength,...

Comparison of Radiation Levels at Network Sites

There are substantial differences in the UV climatology between the various UVSIMN sites. A large portion of the differences can be traced to their geographical locations as lower latitudes experience higher sun elevations and more UV, all other factors being equal. However, the contention that low levels of UV will occur in Polar Regions because of the high latitude is shown here to not be true. Measurements from the seven network sites are presented below. The comparison is based on the...

Synthetic Spectrum Data

Ultraviolet Spectrum Image

The UV-MFRSR instrument, described in Section 8.2.2, makes measurements every three minutes in seven spectral regions, each with a nominal bandwidth of 2 nm. The centers of the bandwidth regions are located at 300, 305, 311, 317, 325, 332 and 368 nm. The measurements are useful in assessing damage to plants and human health, particularly when considered in conjunction with specific Biological Spectral Weighting Functions (BSWFs) see for example Caldwell et al. (1986). The calculation of an...

UVMRPs Role in UVB Agricultural Effects Studies

The previous sections describe UVMRP's monitoring activities and are limited to the physical aspects of UV radiation. In addition, UVMRP has played a role in the investigation of the biological response or effects studies of various plants and animals to UV-B and visible radiation. The goal of these studies is to evaluate the response of plants, forests, ecosystems, and animals to UV-B radiation and other climate stress factors. The program works with agricultural forest researchers to evaluate...

Highlights of Other Collaborations

In addition to the UVMRP sponsored and funded research efforts described in Sections 8.7.1 through 8.7.6, further research collaborations include Cornell University Dr. Craig N. Austin has focused his research on how UV-B radiation affects the development of powdery mildew on the fruit and foliage of wine grape plants grown in the Finger Lakes Region of New York State. For two summers, the UVMRP supplied a portable UV-B monitoring instrument used in some components of the studies. The...

Impact of Ozone Depletion on Primary Productivity

Several studies have suggested that a depletion of the ozone layer could lead to a reduction in the primary production of aquatic ecosystems due to an increase in UV-B radiation (Hader, 1997 Hader et al., 1998). Smith et al., (1992) estimated a 6 -12 reduction in the primary production in the marginal ice of the Southern Ocean for a reduction in the stratospheric ozone from 300 DU - 200 DU. Other studies have indicated that an ozone depletion from 300 DU -150 DU in Antarctica would lead to a...

Abiotic Stress Factors and Crop Yield

Agricultural production and productivity are highly sensitive to changes in climate and weather conditions. Therefore, changes in regional and global climate, particularly climatic variability, affect local as well as global food, fiber, and forest production (Easterling et al., 2007). Atmospheric carbon dioxide, temperature, rainfall patterns, ozone, and UV-B radiation have changed since the dawn of industrial revolution, and the scientific community expects current trends to continue into the...

Crop Responses to UVB and Other Climate Change Factors

Even though UV-B represents a small fraction (0.5 ) of total solar radiation, exposure to UV-B at the current and projected levels is known to elicit a variety of responses to all living organisms, including crop plants (Teramura, 1983 Runeckles and Krupa, 1994 Teramura and Sullivan, 1994 Caldwell et al., 1998 Kakani et al., 2003a). Changes in CO2 and temperature accompanied by emission of ozone-depleting compounds, such as CFCs, CH4, and N2O caused by anthropogenic activities, reduces the...

Climate Change and Aerobiology and Public Health

In recent years, concerns regarding possible links among climate, plant biology, aerobiology, and public health (Ziska et al., 2008) have increased. Atmospheric CO2, the main input needed for photosynthesis, stimulates plant growth however, the rate of stimulation depends on the species. Plants with an indeterminate growth habit will benefit immensely because additional carbon can increase the production of branches tillers and result in more nodes fruiting sites on all branches, thus adding...

Plant Growth and UV Irradiation

Soybean seeds (Glycine max L., cultivars Clark and Clark-magenta) were planted in plots (4.5 m x 2.5 m) at the USDA Agricultural Research Center (ARS), South Farm, Beltsville, MD, with a spacing between rows of 0.4 m, and a density of 35 seeds m-1. One row (4.5 m) of Clark seed was planted next to one row of Clark-magenta seed, and bordered by additional rows of soybeans to simulate field-crowding conditions and to create even sunlight exposure and shading. After germination, plants were...

Field Sampling

Samples were collected on two days, July 9 and July 22 (2000) from the newest, fully-expanded leaves. Average daily UV-B radiation values and climatological data were obtained from the USDA UV-B Monitoring and Research Program website for the Beltsville, MD station, located approximately 300 m from the study site. Overall average daily radiation 2 2 was 68.9 kW m at 300 nm on July 9th and 46.7 kW m at 300 nm on July 22nd. This led to ambient daily weighted (Caldwell, 1971) UV-B levels of 4.2...

Conclusions

In the meta-analysis of Searles et al. (2001), UV-induced changes in foliar chemistry, particularly that of production of epidermal screening compounds, were cited as one of the most common responses to UV-B radiation. In this and several related studies (Sullivan et al., 2007 Xu et al., 2008a, b), we evaluated the consequences of removal of one part of the screening system namely, the flavonols of soybean, and found that they were important screening compounds. This attests to the role of...

Crop Response to Atmospheric CO2 Concentration

The projected increase in atmospheric CO2 is expected to enhance growth and production of agricultural terrestrial plants (Easterling et al., 2007). Studies have also shown that the effects of elevated CO2 on plant growth and yield may depend on photosynthetic pathway, plant species, growth stage, and management practices, such as water and nitrogen applications (Jablonski et al., 2002 Kimball et al., 2002 Ainsworth and Long, 2005). Crops with C3 photosynthetic pathway respond markedly to...

Atmospheric Density

As previously stated, the path length of the stratosphere is much longer than that of the troposphere, but the higher density of the troposphere and its increasing scattering capabilities are believed to enhance the absorptive powers of this region (Bruhl and Crutzen, 1989). Atmospheric pressure increases dramatically toward the earth's surface and as a result, the mean free path for molecular interaction is greatly reduced from its value in the stratosphere. From 40 km (the approximate center...

Comparing Weighting Functions for Erythema and Vitamin D

Spectral Shape Factor Fema

The weighting functions for erythema (McKinlay and Diffey, 1987) and for vitamin D production (Bouillon et al., 2006), as published by the International Commission on Illumination (CIE), are compared in Fig. 2.5 (upper panel). Each of these is arbitrarily normalized to unity at its maximum value. The figure also includes typical global solar irradiance spectra measured at a mid-latitude site at local noon on cloudless days close to the summer and winter solstices. The resolution of the spectra...

Action Spectra and Irradiance Trends

Vis Carboxylic Acid

An action spectrum A(A) is a weighting function of wavelength A that estimates the relative strength of a process (e.g., biological process or material degradation) for each wavelength in a range from A1 to A2. The action spectrum is multiplied by the irradiance I(A, t) to obtain a production function PACT(t). A direct comparison of dose amounts for any causal effect is not given by A(A), but just indicates the relative effect of each wavelength. Frequently, what is wanted is the time...

Solar UV and PAR Irradiance

Measurements of ambient solar UV and PAR were made using a broadband UV 376 sensor (Skye UV-B Skye Instruments, Ltd., Powys, UK) and quantum sensor (LI-185, Li-COR, Inc., Lincoln, NE, USA), respectively, at the Mauna Kea field site during the experiments. Clear-day data during the experiment were regressed against biologically-weighted estimates calculated from solar UV irradiance measured at the USDA UV-B monitoring station UVMFRS radiometer located at the Mauna Loa Meteorological Observatory...

The Instrument

The optical components of the Brewer spectrophotometer are comprised of three parts (1) the fore-optics, (2) the spectrometer, and (3) the photomultiplier housing, as illustrated in Fig. 6.1 (from Fig. 2.5 of the Brewer Instruction Manual, courtesy of Kipp and Zonen). Additional information regarding the optical components can be found in Fig. 2.4 of the Brewer Instruction Manuals. The fore-optics direct incoming radiation onto the entrance slit of the spectrometer. The spectrometer disperses...

Transpiration

Leaf Circle Transpiration

The E of the control plants in the 2007 and 2008 experiments varied between 0.5 and 2.6 mmol H2O m s (Figs. 16.4(a) and 16.5(a)). At VC stage, the Essex control leaves increased transpiration over the course of the experiment which corresponded to the increases in gs (Fig. 16.2(c)). There was no trend evident in the E of the 2007 or 2008 experimental control leaves with increasing PPFD (Fig. 16.5(b)). Although four to five E measurements were made on each plant during daylight hours in 2007,...

UVB Absorbing Compounds and Leaf Pigments

Kehlnaht Bezeichnung

The 2004 greenhouse study evaluated UV-B absorbing compounds and leaf pigment concentrations after 23.4 kJ m-2 UV-Bbe of exposure. The initial content of UV-B absorbance of acidified methanolic leaf extracts of Essex at 300 nm - 320 nm Figure 16.8 Changes in water use efficiency with UV exposure. Differences indicated are UV-Control. Error bars are standard error of the difference. All measurements were made in greenhouse experiments was higher than in Williams 82 and Essex had significantly...

Dosimetry UV Modeling and Instruments

Ultraviolet Ray Instrument For Ocular

Every wavelength causes differing biological effects. Four Action Spectra for different biological targets are shown in Fig. 4.17. It is evident that UV-B is the main culprit for harmful UV consequences, in particular erythema. Convolving a solar UV irradiance spectrum with the specific action spectrum and then integrating Figure 4.17 Action spectra for several biological targets. Source Di Menno et al., 2007 Figure 4.17 Action spectra for several biological targets. Source Di Menno et al.,...

Aerosol Optical Depth

Atmospheric aerosols play an important role in scattering and absorbing radiation as it passes through the atmosphere. The intensity and angular distribution of surface radiation are affected by the aerosols' optical depth (r in Eq. (6.2)), vertical distribution, and absorption and scattering characteristics. Aerosol optical depth (r) is comprised of two components absorbing and scattering (i.e., r rabs + rscat). Aerosols typically reduce surface UV irradiance by a few percent and can reduce...

Estimates of Historical UV Indices

Albedo Measurement Spectrophotometer

Based on historical ozone data and model calculation, the climatology of the UV Index for years preceding the development of the ozone hole was estimated for all sites with the exception of San Diego and Summit. The procedure is explained using South Pole as an example. Historical total ozone data at South Pole are available from observations of Dobson spectrophotometers performed by the Global Monitoring Division (GMD) of NOAA's Earth System Research Laboratory (ESRL) (Climate Monitoring and...