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)...

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...

Conclusions

This study compares the noontime UV-B data collected by the broadband UV-B-1 Pyranometer measurements against synchronous TOMS data measured over 1999 to 2005 across the continental U.S. These analyses were performed in order to provide insights into how the spatial and temporal patterns of UV-B may be collectively used to identify the UV impacts. For the temporal analysis, we compare trends in the data for monthly differences from the mean value over the five-year period. For the spatial...

Emission

This is the creation of electromagnetic radiation generally produced as a result of the interactions between the molecules or atoms in the atmosphere with very high energy photons from very short wavelength radiation. These interactions raise either the molecular or atomic state of the gas or particulate matter above its normal ground state and as a result, the gas or particle can emit a longer wavelength of radiation. This emitted radiation is the result of the gas or particle reverting back...

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...

Immune Function

Although UV-B is strongly absorbed in the skin and in the outer layers of the eye and does not penetrate any deeper into the human body, it can affect the human immune system, because part of the immune system is in the outer layers of skin, and the cells of the skin produce mediators that modulate immune responses both locally and throughout the body (De Gruijl, 1995 Longstreth et al., 1998). De Fabo (1994) and Chapman (1995) suggested that UV-B is the probable cause of infectious diseases and...

Introduction

The goal of this review is to summarize recent information on the effect of ultraviolet radiation (UV) on human health in urban areas, and the degree to which urban landscapes might be managed to optimize UV exposure for improved health. Considering both the negative and positive health effects of UV exposure, would urban planning to increase tree cover form an effective public health intervention Can optimum tree arrangements and species selections be prescribed More specific questions arise...

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...

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...

Radiative Transfer Modeling 921 Sun Earth Geometry

Because the earth moves around the sun in an elliptical orbit, the earth-sun distance, R, varies throughout the year, by about 3.4 from its minimum value on about January 3 to its maximum value on about July 3. Thus, the variation in R and therefore, in the extraterrestrial solar irradiance, is about 6.9 , which implies that the radiation incident at the top of the atmosphere is almost 7 larger in January (Southern hemisphere) than in July (Northern hemisphere). The illumination of the earth's...

References

Arola A, and Koskela T (2004) On the sources of bias in aerosol optical depth retrieval in the UV range. J. Geophys. Res. 109 D08209, D0I 10.1029 2003JD004375 Bais AF (1997) Absolute spectral measurements of direct solar ultraviolet irradiance with a Brewer spectrophotometer. Appl. Opt. 36(21) 5199 - 5204 Bais AF, Zerefos CS, Meleti C, and Ziomas IC (1994) Comparison of UV-B measurements performed with a Brewer spectrophotometer and a new UVB-1 broadband detector. In Hudson RD (ed) Ozone in 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...

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...

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,...

Concluding Remarks

Global dimming, in addition to affecting the amount of visible radiation, will affect the amount of UV radiation reaching the earth's surface. Our experiment using fava beans (Viciafaba) grown in the high UV environment of Mauna Kea, Hawaii, was designed to detect whether a 13 reduction in visible radiation (and associated reduction in UV radiation), a level similar to global dimming, could influence plant growth and leaf optical properties for UV-transmittance. We found that structural...

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...

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...

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...

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...

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...

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...

Effects of Solar UV on Human Health and Epidemiology

Human diseases that are linked to UV radiation as either the causative agent or as a factor in susceptibility to disease include several types of skin cancer, eye disease, and damage to the immune system. In addition, it is the UV, primarily UV-B, which is responsible for sunburn and skin aging and wrinkling (Weary, 1996). Sunburn itself is a health issue, but more importantly, some cancers are believed to be related to numerous sunburn episodes. There are also benefits to UV- radiation...

Information and Protection Programs

The most important, effective, and rapid action for the reduction of the health risks caused by UV exposure is to provide people, across the globe, with accurate information. Possession of adequate knowledge of the cause and effect of sunburn, tanning methodology, and the best known practices for sun exposure, is the only way to reduce UV radiation induced health risks. Thus, over the last 20 years, many international, national, governmental, and private institutions have published numerous...

Palmer Station

The patterns of measured and historical UV Indices at Palmer are similar to those at McMurdo, but the magnitudes are different. The highest UV Index occurs in spring, reaching a maximum of 14.8. The 90th percentile is considerably enhanced during spring. Particularly large UV-B levels were observed in November and early December during years when the polar vortex became unstable and air masses with low ozone concentration moved toward the Antarctic Peninsula. In combination with the relatively...

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,...

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...

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...

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...

Measuring Leaf Optical Properties

Leaf reflectance and transmittance were measured with an integrating sphere (Optronic IS-1000) following the procedures by Optronic Laboratories, Inc. (1997). The integrating sphere, powered by a constant power-output supply (OL 65 Programmable Current Source, Optronic, FL), was used in combination with an irradiance standard (Optronic OL Series 752-10) and a high accuracy UV Visible spectroradiometer (OL 754) connected to a computer. Spectral scanning was performed from 250 nm - 800 nm at 5 nm...

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...

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...

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...

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...

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...

Impact of Solar UV on the Environment

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...

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...

Comparing Weighting Functions for Erythema and Vitamin D

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...

Measuring the Light Penetration and Distribution within Leaf Tissues

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...

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...

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...

Estimating UV Trends Ground Based

An excellent example of UV trend detection is from ground-based measured solar irradiances at 305 nm and 324 nm at Thessaloniki, Greece. The irradiances shown in Fig. 5.13 are for cloud-free skies at a constant SZA of 63 (WMO, 2007, an extension of Bias et al., 1993). These data are obtained from a carefully maintained Brewer spectrometer located in an industrial area that is subjected to moderate amounts of pollution generated locally and also reaching Greece from other countries in Europe....

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...

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...

Effective Temperature of Atmospheric Ozone

The temperature of atmospheric ozone influences the amount of UV radiation reaching the surface. The absorption of radiation by ozone in the UV is temperature dependent and generally increases with temperature. The effective temperature of atmospheric ozone (i.e., average temperature of column ozone weighted by ozone concentration) can vary by up to 20 C depending on latitude and season. Over this temperature range, ozone absorption can change by up to 10 at some wavelengths. It is possible to...

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...

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...

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)...

Changes in Ultraviolet and Visible Solar Irradiance 1979 to 2008

Code 613.3 Greenbelt, MD 20771 USA E-mail jay.r.herman nasa.gov Abstract A description is presented of instruments and requirements for measuring ultraviolet (UV) and visible irradiance and estimating long-term changes in irradiance from the ground-based and satellite data The 30-year changes in zonal average UV irradiances are estimated from changes that have occurred in ozone amount and cloud cover as a function of latitude and season. Ozone changes have been obtained from a multiple...

Melanoma

Cutaneous malignant melanoma (CM) is much more life threatening than BCC or SCC. The CM rate increased in the U.S. from 6.8 100,000 in 1973 to 17.4 100,000 in 1999 (Saraiya et al., 2004), and to an average of 19.4 100,000 from 2001 to 2005 (National Cancer Institute, It has been noted for many years that melanoma rates tend to be higher at lower latitudes, following the trend toward a higher incidence of solar radiation with decreasing latitude (Whiteman and Green, 1999). It has been estimated...

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...

Structural and Biomass Measurements

After 30 days of growth, plants were removed from under the filter and taken indoors for structural and epidermal transmittance measurements and then destructively harvested for biomass quantification. Structural measurements included total height (soil surface to top of terminal bud), number of internodes, and height of each internode. Plants were then harvested and sorted into components (leaf, stem, branches), oven dried at 60 C for 24 hours and weighed for dry mass determinations. Leaf mass...

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...

Database Design and Website Interface

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)....

Field Site

Ray Leach Cone Tainers

Studies were conducted during summer at a field site located on the south slope of Mauna Kea, Hawaii, USA (2,800 m elev. 19 45'N, 155 27'W). Climate at the study site is Mediterranean, with warm relatively dry summers and cooler, wetter winters. Average summer high temperatures are ca. 20 C - 22 C and annual precipitation is ca. 400 mm. The light climate is characterized by high PAR (max clear day ca. 2,100 (imol m-2 s-1) and very high UV-B and UV-A levels (max clear day ca. 5.1 and 69 W m ,...

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...

UVI Spatial Analysis

Spatial patterns of UV-I observed by both data sources were also compared at a 4 x 4 km spatial resolution. Figures 10.4 -10.7 collectively delineate the comparison of seasonal UV-I spatial patterns between ground-based measurements and TOMS satellite data. Figure 10.4 first summarizes these spatial patterns of the ground surface UV-I data by season. The two data sources portray very similar spatial distributions of springtime UV-I (Fig. 10.4). The maximum of the UV-I is 9 for the USDA...

Photosynthesis and Transpiration Measurements

In 2007 and 2008, A and E were measured on the highest fully-expanded leaf of 3 and 16 replicates, respectively, in each treatment. Leaves were kept as close to their natural angle as possible (nearly horizontal) while maximizing solar irradiance. In both experiments, A and E were measured at the same times as the gs measurements (see Section 16.2.4) using a portable open photosynthesis system (CI 340, CID, Inc., Camas, WA, USA). In 2004, A and E were measured on 9 replicates in each treatment...

TOMS Dataset

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...

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...

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...

Study

A study by Barnard (2001) shows that specific air pollutants can reduce the increased surface levels of UV radiation, and offers an explanation for why the expected surface UV increases, caused by decreases in stratospheric ozone, have not been observed, especially in urban regions. Air pollution data (NOX, O3, PM-10, SO2) collected from an EPA UV monitoring site at the University of California at Riverside (UCR), combined with data from a site operated by the California Air Resources Board in...

UVB Absorbing Compounds and Leaf Pigments

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...

I0l

In represents the photon counts measured by the Brewer at wavelength A and corresponds to the photon counts that would be measured at the top of the earth's atmosphere. The sum of aerosol and gas extinction is Tx and m is the air mass defined as the cosecant of the solar zenith angle. Once the I0 has been characterized, the total atmospheric optical depth (ra,x), at a specific wavelength, is calculated using the following Ii is the Brewer photon count as measured by the PS routine. The natural...

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...

McMurdo Station

McMurdo is affected by the ozone hole from September until early December (Fig. 3.6(a)). The maximum UV Index was 7.6 and occurred in November UV Indices measured after the solstice were below 5.5. The 90th percentile also exhibits a distinct maximum in late November. The average UV Index is fairly symmetric within 40 days about the solstice, but the 10th percentile is lower in the spring than in the summer. This feature is again a consequence of the Brewer- Dobson circulation. Historical UV...

Calculating RAF0

If the RAF is calculated directly from the power law definition F1 F2 (A A)RAF or RAF ln(F1 F2) ln(. 2 i), the result will have a dependence on ozone amount for any range of Q relative to the reference amount (Fig. 5.A1). In this study, the RAF is calculated as the best fit to the function i)RAF with the requirement that U is approximately 1 (Fig. 5.A2). This approximation works well for the entire range of SZA (Fig. 5.A3), the ozone range 200 DU to 600 DU, and for all four action spectra...

Radiative Transfer in the Coupled Atmosphere SnowIce Ocean Casio System Review of Modeling Capabilities

12 2 Knut Stamnes , Borge Hamre , and Jakob J. Stamnes 1 Light and Life Laboratory, Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ 07030, USA E-mail Knut.Stamnes stevens.edu 2 Department of Physics and Technology, University of Bergen, Postboks 7800, 5020 Bergen, Norway E-mail Borge.Hamre ift.uib.no E-mail Jakob.Stamnes ift.uib.no Abstract A review is provided of ultraviolet (UV) and visible radiative transfer in an atmosphere-sea-ice-ocean system...

UV Reflectivity

The radiation environment in urban areas depends, to a large extent, on the reflectivity of the building materials, paving surfaces, and vegetation. Reflectivities in the UV for many surfaces have been tabulated (Sliney, 1986 Blumthaler and Ambach, 1988 Feister and Grewe, 1995 Heisler and Grant, 2000a). However, reflectivity differences for particular materials within a type (i.e., variances in (1) color and kind of paint, (2) concretes, (3) building siding, and (4) specialty glass) seldomly...

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...

Action Spectra and Irradiance Trends

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...

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...

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...

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...

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...

Main Objectives

The main objective of this UV-B study was to examine the qualitative effects of UV radiation on the early development of soybean (Glycine max), using two varieties Williams and Forrest. The goals of the study were to (1) evaluate the initial responses to low dose UV radiation in newly emerging plants up to 28 days post-germination (2) evaluate effects of UV radiation on the seed production and viability of seed by examining the viability of the seeds produced from plants receiving a low dose UV...

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...

Leaf Optical Properties

Residential Ductwork Layout

Changes in leaf spectral reflectance, transmittance, and absorbance to UV visible light of pecan leaves throughout a growing season are illustrated in Fig. 18.3. The changes in leaf optical properties were relatively small in UV-B (280 nm - 320 nm) and UV-A (320 nm - 400 nm) spectral regions compared to that of the visible spectral region (400 nm - 760 nm). Throughout the growing season, pecan leaves reflected 4 - 8 , transmitted 0 -1 , and absorbed up to 96 of UV radiation (280 nm - 400 nm)....

Utah State University

Stephen Flint, and colleagues from Utah State University, combined numerous UV radiation related studies to determine and evaluate various UV-B and UV-A biological weighting functions. Weighted UV doses based on this and other work are routinely calculated and posted on the UVMRP website. Field experiments were conducted on Mauna Kea, HI at approximately 3000 m elevation to test the relative importance of the UV-B and UV-A wavebands under near ambient, no UV-B, and no UV-A or...

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...

Ultraviolet Radiation and Its Interaction with Air Pollution

Wenny 1 North Carolina State University, Department of Marine, Earth, and Atmospheric Sciences, Campus Box 8208 Raleigh, North Carolina 27695-8208, USA E-mail SBarn46193 aol.com 2 MODIS Characterization Support Team (MCST) Sigma Space Corp. 10210 Greenbelt Road, Suite 500 Lanham, MD 20706 E-mail brian.wenny gmail.com Abstract This chapter contains the methodology, along with study examples, that show the types of interactions that the sun's ultraviolet (UV)...

Human Exposure to UV

From the viewpoint of human exposure to UV, the maximum clear-sky UV irradiance and exposure occurs in the equatorial zone latitudes, 23.3 ,following the seasonal sub-solar point, and at high mountain altitudes. In general, UV erythemal, UV-A, and UV-B irradiance decreases with increasing latitude outside of the equatorial zone, due to the decreases in maximum daily noon solar elevation angles and for UV-B increases in ozone amount. An exception occurs for UV-B wavelengths at southern mid- to...

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...

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...

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...

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...

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...

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.,...

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...

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,...

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...

Scattering

As one would guess, this denotes a change in the direction in which radiation propagates. Radiation is shifted out of one direction and into another. In general, there can be a shift in frequency upon scattering as well. The wavelength dependence of molecular scattering (i.e., Rayleigh scattering) is proportional to A 4, so this scattering will be more significant in the UV range than in the visible. The change in direction of radiation associated with scattering is described by the phase...

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...

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...

Spectrum of Solar Radiation

Extraterrestrial Radiation

Figure 9.1 shows the incident UV, visible, and near-infrared parts of the spectral solar irradiance (wavelengths shorter than 1,000 nm) measured on board an earth-orbiting satellite (Rottman et al., 1993). Spectra of an ideal blackbody at several temperatures are also shown in Fig. 9.1. Given the requirement that the total solar energy emitted be the same as that emitted by a blackbody, one finds that the sun's effective temperature is 5,778 K. If the radiating layers of the sun had the same...

Peak UV

For some biological processes, peak UV intensity may be more important than the mean value, and while we cannot be sure about evolutionary pressures, it is possible that UV intensities were much greater during the earlier history of the planet than at present (Bj rn and McKenzie, 2007). However, from our current perspective, changes in UV over the past, and future, few decades are more relevant. It is likely that peak UV over these time scales has already occurred, since it is expected that...

Dosimetry UV Modeling and Instruments

Bmw 2002 Body

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.,...

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...

Depth of Light Penetration into Leaf Tissues

Light Penetration Depth

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...

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...

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,...