دانلود رایگان مقاله لاتین آب خاک در تعیین دوز ازون سیتوتوکسیک از سایت الزویر
عنوان فارسی مقاله:
بررسی نقش محدودیت آب خاک در تعیین آستانه دوز ازون سیتوتوکسیک (PODY)
عنوان انگلیسی مقاله:
Assessing the role of soil water limitation in determining the Phytotoxic Ozone Dose (PODY) thresholds
سال انتشار : 2016
برای دانلود رایگان مقاله آب خاک در تعیین دوز ازون سیتوتوکسیک اینجا کلیک نمایید.
مقدمه انگلیسی مقاله:
1. Introduction
Ozone (O3) is a key air pollutant and a powerful greenhouse gas (IPCC, 2014). In the Northern hemisphere, tropospheric concentrations have approximately doubled in the last century (Vingarzan, 2004). Emission control measures have successfully reduced the peaks, while annual averages are still increasing (Sicard et al., 2013, 2016a; Paoletti et al., 2014). Intense solar radiation, high air temperature and stagnation of the air promote O3 formation from its precursors, i.e. nitrogen oxides, volatile organic compounds, carbon monoxide and methane (e.g. Fiore et al., 2002; Sicard et al., 2009).This is why O3 concentrations are more elevated in Southern European countries bordering the Mediterranean sea, where photochemical activity is strong (Butkovic et al., 1990), than in central and Northern Europe (EEA, 2013). Ozone is considered a serious phytotoxic threat to all vegetation (Paoletti, 2007), and present tropospheric concentrations are high enough to negatively affect terrestrial ecosystems (Wittig et al., 2009; Mills et al., 2011a: Fares et al., 2013a). Even though Mediterranean vegetation is adapted to face oxidative stressors, such as water deficit, heat and elevated solar radiation, and is thus more O3 tolerant than mesophilic vegetation (Paoletti, 2006), visible O3-induced foliar injury occurs (Günthardt-Goerg and Vollenweider, 2007; Paoletti et al., 2009a,b; Sicard et al., 2010; Mills et al., 2011a; Sicard et al., 2016b), suggesting that atmospheric concentrations of O3 reach toxic levels. In the last decades, scientific consensus has been reached to recommend the use of stomatal O3 flux to evaluate O3 effects on vegetation, as it can explain the observed effects better than ambient O3 concentration (Paoletti and Manning, 2007; Mills et al., 2011b). Ozone uptake through stomata can be calculated using the multiplicative model of stomatal conductance (Jarvis, 1976), introduced within the risk assessment methodology of the UNECE Convention on Long-range Transboundary Air Pollution (CLRTAP) as the Deposition of Ozone for Stomatal Exchange (DO3SE) model (Emberson et al., 2000, 2001; CLRTAP, 2015). By introducing a threshold flux (Y) to reflect detoxification processes, and by accumulating over the growing season, we obtain the Phytotoxic Ozone Dose (PODY), a flux-based impact index that incorporates the effects of plant phenology and the most important environmental variables on stomatal function, i.e. air temperature, solar radiation, vapour pressure deficit and soil water content (SWC). However, the scarcity of measured data and/or reliable soil moisture models has been a serious obstacle to the inclusion of stomatal SWC limitation in PODY calculations, thus resulting in the compromise of considering ‘worst-case’ impact scenarios with no SWC effects on O3 fluxes (Simpson et al., 2007; Tuovinen et al., 2009; CLRTAP, 2015). For example, SWC has been incorporated into the recent versions of the EMEP chemical transport model (Simpson et al., 2012), which is widely employed within the European air pollution abatement work; however, an explicit treatment of SWC effect is deliberately ignored in the PODY calculations that serve scenario analysis and optimisation runs with large-scale integrated assessment models (CLRTAP, 2015). This kind of scenario is helpful when determining ozone risk for soils and regions that rarely experience drought stress, or when working with irrigated crops or irrigated trees, but is poorly applicable in risk assessment for unirrigated forests, especially in the Mediterranean region. Different threshold fluxes, below which O3 uptake is assumed to cause no injury to plants, are assumed for different vegetation types (CLRTAP, 2015; Mills et al., 2011a). At present, a threshold Y ¼ 1 nmol O3 m2 s 1 (i.e. POD1) is recommended for the protection of forests and grasslands (CLRTAP, 2015), Y ¼ 6 nmol O3 m2 s 1 is recommended for crops (CLRTAP, 2015), and a value of Y ¼ 2 nmol O3 m2 s 1 is under discussion as a potentially new threshold for forests (Büker et al., 2015). By using modelled input data for grid-based forest sites distributed in temperate and Mediterranean climates in Southern Europe, we here aim at quantifying the differences resulting from using DO3SE for the calculation of PODY without considering water limitation to stomatal exchange, as compared to the full model. As the sensitivity of such a threshold-based index to changes in the input is known to increase with increasing threshold (Tuovinen et al., 2007), we also quantify how this difference depends on the threshold flux Y. This knowledge is needed for a proper modelling of global O3 risks to vegetation and for selecting the best legislative standards to protect plants from O3. We hypothesize that (i) the difference between the PODY values calculated with and without soil water limitation is not negligible; (ii) this difference signifi- cantly increases with increasing Y thresholds; and (iii) this difference is higher for Mediterranean vegetation than for temperate vegetation. As the magnitude of these effects may be affected by the accuracy of the models employed, similar calculations were performed with field data measured at a Mediterranean forest site. The aim of this comparison with measured data was to confirm the magnitude of the differences, rather than to validate the model which would require much more field data. 2. M
برای دانلود رایگان مقاله آب خاک در تعیین دوز ازون سیتوتوکسیک اینجا کلیک نمایید.
کلمات کلیدی:
Assessing the role of soil water limitation in determining the Phytotoxic ... https://www.deepdyve.com/.../assessing-the-role-of-soil-water-limitation-in-determini... Read "Assessing the role of soil water limitation in determining the Phytotoxic Ozone Dose (PODY) thresholds, Atmospheric Environment" on DeepDyve, the ... LIFE10 ENV/FR/000208 ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=search... FO3REST - Ozone and Climate Change Impacts on French and Italian Forests: ... of Ozone and Stomatal Exchange (DO3SE) model for calculating ozone flux and for ... called Phytotoxic Ozone Dose above a threshold Y of uptake (PODY), has ... [PDF]FO3REST - Ozone and Climate Change Impacts on French and Italian ... ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction... Phytotoxic Ozone Dose above a threshold Y of uptake. (PODY) is the ... determine the best time-window of PODY accumulation;. (iv) to suggest new ... [PDF]Ozone damage to vegetation - Milieurapport www.milieurapport.be/.../2013-12_Summary%20ozone%20damage%20to%20vegeta... exposure over a Threshold of 40 ppb) was defined as the sum of hourly O3 concentrations above a ... suggested as a basis for calculating the hourly O3 flux. ... Phytotoxic Ozone Dose PODY (mmol O3 m-2 plant leaf area), which is the sum of ... Air Pollution Modeling and its Application XXIV https://books.google.com/books?isbn=3319244787 Douw G. Steyn, Nadine Chaumerliac - 2016 - Science Excessive tropospheric ozone concentrations are not only harmful for human health but ... (Accumulated Ozone exposure over a Threshold of 40 ppb) which has been ... forest trees and grassland: the Phytotoxic Ozone Dose, PODY (mmol O3m−2 ... One of the models for calculating stomatal conductance that have been ... Critical Loads and Dynamic Risk Assessments: Nitrogen, Acidity and ... https://books.google.com/books?isbn=9401795088 Wim de Vries, Jean-Paul Hettelingh, Maximilian Posch - 2015 - Science ... OECD ORCHESTRA PELCOM PLA PNEC PnET-BGC POC PODY PROFILE ... Probability of OCcurrence Phytotoxic Ozone Dose above a threshold of Y nmol ...
