Hot Summers: Effect of Extreme Temperatures on Ozone in Sydney, Australia

Poor air quality is often associated with hot weather, but the quantitative attribution of high temperatures on air quality remains unclear. In this study, the effect of elevated temperatures on air quality is investigated in Greater Sydney using January 2013, a period of extreme heat during which temperatures at times exceeded 40 ∘ C, as a case study. Using observations from 17 measurement sites and the Weather Research and Forecasting Chemistry (WRF-Chem) model, we analyse the effect of elevated temperatures on ozone in Sydney by running a number of sensitivity studies in which: (1) the model is run with biogenic emissions generated by MEGAN and separately run with monthly average Model of Emissions of Gases and Aerosols from Nature ( MEGAN) biogenic emissions (for January 2013); (2) the model results from the standard run are compared with those in which average temperatures (for January 2013) are only applied to the chemistry; (3) the model is run using both averaged biogenic emissions and temperatures; and (4 and 5) the model is run with half and zero biogenic emissions. The results show that the impact on simulated ozone through the effect of temperature on reaction rates is similar to the impact via the effect of temperature on biogenic emissions and the relative impacts are largely additive when compared to the run in which both are averaged. When averaged across 17 sites in Greater Sydney, the differences between ozone simulated under standard and averaged model conditions are as high as 16 ppbv. Removing biogenic emissions in the model has the effect of removing all simulated ozone episodes during extreme heat periods, highlighting the important role of biogenic emissions in Australia, where Eucalypts are a key biogenic source.

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Experimental heatwaves negatively impact sperm quality in the zebra finch

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.2547 ◽

2018 ◽

Vol 285 (1871) ◽

pp. 20172547 ◽

Cited By ~ 19

Author(s):

Laura L. Hurley ◽

Callum S. McDiarmid ◽

Christopher R. Friesen ◽

Simon C. Griffith ◽

Melissah Rowe

Keyword(s):

Male Fertility ◽

Elevated Temperatures ◽

Sperm Quality ◽

Recovery Period ◽

Heat Exposure ◽

Effect Of Temperature ◽

Normal Morphology ◽

Warming World ◽

The Impact

For sexually reproducing species, functionally competent sperm are critical to reproduction. While high atmospheric temperatures are known to influence the timing of breeding, incubation and reproductive success in birds, the effect of temperature on sperm quality remains largely unexplored. Here, we experimentally investigated the impact of ecologically relevant extreme temperatures on cloacal temperature and sperm morphology and motility in zebra finches Taeniopygia guttata . We periodically sampled males exposed to 30°C or 40°C temperatures daily for 14 consecutive days. Following a 12-day (23°C) recovery period, birds were again exposed to heat, but under the alternate treatment (e.g. birds initially exposed to 40°C were exposed to 30°C). Elevated temperatures led to an increase in cloacal temperature and a reduction in the proportion of sperm with normal morphology; these effects were most notable under 40°C conditions, and were influenced by the duration of heat exposure and prior exposure to high temperature. Our findings highlight the potential role of temperature in determining male fertility in birds, and perhaps also in constraining the timing of avian breeding. Given the increased frequency of heatwaves in a warming world, our results suggest the need for further work on climatic influences on sperm quality and male fertility.

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Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure

Materials ◽

10.3390/ma12121995 ◽

2019 ◽

Vol 12 (12) ◽

pp. 1995 ◽

Cited By ~ 3

Author(s):

Yongxin Yang ◽

Yanju Jiang ◽

Hongjun Liang ◽

Xiaosan Yin ◽

Yue Huang

Keyword(s):

Tensile Strength ◽

Elastic Modulus ◽

Elevated Temperature ◽

Tensile Properties ◽

Failure Mode ◽

Elevated Temperatures ◽

Strain Curve ◽

Effect Of Temperature ◽

Temperature Exposure ◽

The Impact

Elevated temperature exposure has a negative effect on the performance of the matrix resin in Carbon Fiber Reinforced Plastics (CFRP) plates, whereas limited quantitative research focuses on the deteriorations. Therefore, 30 CFRP specimens were designed and tested under elevated temperatures (10, 30, 50, 70, and 90 °C) to explore the degradations in tensile properties. The effect of temperature on the failure mode, stress-strain curve, tensile strength, elastic modulus and elongation of CFRP plates were investigated. The results showed that elevated temperature exposure significantly changed the failure characteristics. When the exposed temperature increased from 10 °C to 90 °C, the failure mode changed from the global factures in the whole CFRP plate to the successive fractures in carbon fibers. Moreover, with temperatures increasing, tensile strength and elongation of CFRP plates decreases gradually while the elastic modulus shows negligible change. Finally, the results of One-Way Analysis of Variance (ANOVA) show that the degradation of the tensile strength of CFRP plates was due to the impact of elevated temperature exposure, rather than the test error.

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Solar “brightening” impact on summer surface ozone between 1990 and 2010 in Europe – a model sensitivity study of the influence of the aerosol–radiation interactions

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-9741-2018 ◽

2018 ◽

Vol 18 (13) ◽

pp. 9741-9765 ◽

Cited By ~ 3

Author(s):

Emmanouil Oikonomakis ◽

Sebnem Aksoyoglu ◽

Martin Wild ◽

Giancarlo Ciarelli ◽

Urs Baltensperger ◽

...

Keyword(s):

Air Quality ◽

Surface Ozone ◽

Biogenic Emissions ◽

Base Case ◽

Air Quality Model ◽

Quality Model ◽

Ozone Concentrations ◽

Photolysis Rates ◽

Ozone Trends ◽

The Impact

Abstract. Surface solar radiation (SSR) observations have indicated an increasing trend in Europe since the mid-1980s, referred to as solar “brightening”. In this study, we used the regional air quality model, CAMx (Comprehensive Air Quality Model with Extensions) to simulate and quantify, with various sensitivity runs (where the year 2010 served as the base case), the effects of increased radiation between 1990 and 2010 on photolysis rates (with the PHOT1, PHOT2 and PHOT3 scenarios, which represented the radiation in 1990) and biogenic volatile organic compound (BVOC) emissions (with the BIO scenario, which represented the biogenic emissions in 1990), and their consequent impacts on summer surface ozone concentrations over Europe between 1990 and 2010. The PHOT1 and PHOT2 scenarios examined the effect of doubling and tripling the anthropogenic PM2.5 concentrations, respectively, while the PHOT3 investigated the impact of an increase in just the sulfate concentrations by a factor of 3.4 (as in 1990), applied only to the calculation of photolysis rates. In the BIO scenario, we reduced the 2010 SSR by 3 % (keeping plant cover and temperature the same), recalculated the biogenic emissions and repeated the base case simulations with the new biogenic emissions. The impact on photolysis rates for all three scenarios was an increase (in 2010 compared to 1990) of 3–6 % which resulted in daytime (10:00–18:00 Local Mean Time – LMT) mean surface ozone differences of 0.2–0.7 ppb (0.5–1.5 %), with the largest hourly difference rising as high as 4–8 ppb (10–16 %). The effect of changes in BVOC emissions on daytime mean surface ozone was much smaller (up to 0.08 ppb, ∼ 0.2 %), as isoprene and terpene (monoterpene and sesquiterpene) emissions increased only by 2.5–3 and 0.7 %, respectively. Overall, the impact of the SSR changes on surface ozone was greater via the effects on photolysis rates compared to the effects on BVOC emissions, and the sensitivity test of their combined impact (the combination of PHOT3 and BIO is denoted as the COMBO scenario) showed nearly additive effects. In addition, all the sensitivity runs were repeated on a second base case with increased NOx emissions to account for any potential underestimation of modeled ozone production; the results did not change significantly in magnitude, but the spatial coverage of the effects was profoundly extended. Finally, the role of the aerosol–radiation interaction (ARI) changes in the European summer surface ozone trends was suggested to be more important when comparing to the order of magnitude of the ozone trends instead of the total ozone concentrations, indicating a potential partial damping of the effects of ozone precursor emissions' reduction.

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Contribution of emissions to concentrations: the TAGGING 1.0 submodel based on the Modular Earth Submodel System (MESSy 2.52)

Geoscientific Model Development ◽

10.5194/gmd-10-2615-2017 ◽

2017 ◽

Vol 10 (7) ◽

pp. 2615-2633 ◽

Cited By ~ 13

Author(s):

Volker Grewe ◽

Eleni Tsati ◽

Mariano Mertens ◽

Christine Frömming ◽

Patrick Jöckel

Keyword(s):

Air Quality ◽

Tropospheric Ozone ◽

Radiative Forcing ◽

Road Traffic ◽

Computing Time ◽

Reaction Rates ◽

Traffic Emissions ◽

Time Step ◽

Road Traffic Emissions ◽

The Impact

Abstract. Questions such as what is the contribution of road traffic emissions to climate change? or what is the impact of shipping emissions on local air quality? require a quantification of the contribution of specific emissions sectors to the concentration of radiatively active species and air-quality-related species, respectively. Here, we present a diagnostics package, implemented in the Modular Earth Submodel System (MESSy), which keeps track of the contribution of source categories (mainly emission sectors) to various concentrations. The diagnostics package is implemented as a submodel (TAGGING) of EMAC (European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/MESSy Atmospheric Chemistry). It determines the contributions of 10 different source categories to the concentration of ozone, nitrogen oxides, peroxyacytyl nitrate, carbon monoxide, non-methane hydrocarbons, hydroxyl, and hydroperoxyl radicals ( = tagged tracers). The source categories are mainly emission sectors and some other sources for completeness. As emission sectors, road traffic, shipping, air traffic, anthropogenic non-traffic, biogenic, biomass burning, and lightning are considered. The submodel obtains information on the chemical reaction rates, online emissions, such as lightning, and wash-out rates. It then solves differential equations for the contribution of a source category to each of the seven tracers. This diagnostics package does not feed back to any other part of the model. For the first time, it takes into account chemically competing effects: for example, the competition between NOx, CO, and non-methane hydrocarbons (NMHCs) in the production and destruction of ozone. We show that the results are in-line with results from other tagging schemes and provide plausibility checks for concentrations of trace gases, such as OH and HO2, which have not previously been tagged. The budgets of the tagged tracers, i.e. the contribution from individual source categories (mainly emission sectors) to, e.g., ozone, are only marginally sensitive to changes in model resolution, though the level of detail increases. A reduction in road traffic emissions by 5 % shows that road traffic global tropospheric ozone is reduced by 4 % only, because the net ozone productivity increases. This 4 % reduction in road traffic tropospheric ozone corresponds to a reduction in total tropospheric ozone by ≈  0.3 %, which is compensated by an increase in tropospheric ozone from other sources by 0.1 %, resulting in a reduction in total tropospheric ozone of ≈  0.2 %. This compensating effect compares well with previous findings. The computational costs of the TAGGING submodel are low with respect to computing time, but a large number of additional tracers are required. The advantage of the tagging scheme is that in one simulation and at every time step and grid point, information is available on the contribution of different emission sectors to the ozone budget, which then can be further used in upcoming studies to calculate the respective radiative forcing simultaneously.

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Impact of climate change on photochemical air pollution in Southern California

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-3745-2009 ◽

2009 ◽

Vol 9 (11) ◽

pp. 3745-3754 ◽

Cited By ~ 14

Author(s):

D. E. Millstein ◽

R. A. Harley

Keyword(s):

Air Quality ◽

Southern California ◽

Reaction Rates ◽

Biogenic Emissions ◽

Western Boundary ◽

Technology Change ◽

Increased Temperature ◽

Time Period ◽

Global Background ◽

Atmospheric Reaction

Abstract. The effects of future climate and emissions-related perturbations on ozone air quality in Southern California are considered, with an assumed increase to 2× pre-industrial levels for global background levels of carbon dioxide. Effects of emission and climate-related forcings on air quality are superimposed on a summer 2005 high-ozone time period. Perturbations considered here include (a) effect of increased temperature on atmospheric reaction rates, (b) effect of increased temperature on biogenic emissions, (c) effect of increased water vapor concentrations, (d) effect of increased pollutant levels at the inflow (western) boundary, and (e) effect of population growth and technology change on emissions within Southern California. Various combinations of the above perturbations are also considered. The climate-related perturbations (a–c) led to combined peak 1-h ozone increases of up to 11 ppb. The effect on ozone was greatly reduced when the temperature increase was applied mostly during nighttime hours rather than uniformly throughout the day. Increased pollutant levels at the inflow boundary also led to ozone increases up to 5 ppb. These climate and inflow-related changes offset some of the anticipated benefits of emission controls within the air basin.

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Short-term creep behavior of multi-axial warp knitted fabric-reinforced polyethylene matrix composites

Textile Research Journal ◽

10.1177/0040517518775910 ◽

2018 ◽

Vol 89 (8) ◽

pp. 1522-1532

Author(s):

Lingxiao Jing ◽

Peng Hu Deng ◽

Jing Zhao ◽

Wang Ting ◽

Jinhua Jiang ◽

...

Keyword(s):

Relaxation Time ◽

Material Parameter ◽

Elevated Temperatures ◽

Fiber Content ◽

Effect Of Temperature ◽

Short Term ◽

Polyethylene Matrix ◽

Term Creep ◽

The Impact ◽

Short Term Creep

Short-term creep experiments of composites of polyethylene reinforced with polyester fiber multi-axial warp knitted (MWK) fabrics were carried out for tensile and shear modes in three directions. This work primarily focuses on using the Burgers and Findley models to obtain parameters associated with stress level, temperature, and structure of MWK fabrics. Specifically, the material parameter A of the Findley model has higher values at elevated temperatures, which is contrary to the impact of fiber content along the loading direction. The material parameter n rises with an increasing temperature and is not affected by the fiber content. In terms of the Burger parameters, material parameters E1, E2, and η1 have a downside as temperature increases. The relationship of these parameters with fiber content is contrary to their relationship with temperature. There is no significant effect of temperature and fiber content on relaxation time, whereas there is an upward trend of relaxation time with increases in stress.

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Analyzing the Effect of Temperature on Squash Ball Impacts Using High-Speed Camera Recordings

Periodica Polytechnica Mechanical Engineering ◽

10.3311/ppme.18381 ◽

2021 ◽

Author(s):

Bence Ferenc Berencsi ◽

Attila Kossa

Keyword(s):

High Speed ◽

Elevated Temperatures ◽

Primary Objective ◽

Effect Of Temperature ◽

High Speed Camera ◽

Compression Tests ◽

Low Velocity ◽

Different Types ◽

Dynamical Parameters ◽

The Impact

Description of the impact characteristics of different types of balls has a great importance in sport science and in engineering. The primary objective of the present paper is to investigate the effect of the temperature on the impacts of different types of squash balls from a given company. The shots were performed using a self-built air-cannon. The impacts were recorded by a high-speed camera and the recorded videos were analyzed by an image-processing method based on a background subtraction technique. Summarizing the main dynamical parameters, we can conclude that increasing the initial speed will decrease the contact time, the coefficient of restitution (COR) and the rebound resilience, whereas these parameters increase at elevated temperatures. The compression tests revealed that within the low velocity range the deformation of the ball’s material and not the compression of the inner gas is the main contribution in the force needed to compress the ball. However, when the ball suffers large deformations, the internal air pressure has a huge effect on the rebound behavior. The measurements revealed that there is an optimal initial velocity distinct from the maximum one where the rebound velocity of the ball is higher than in all other cases. From the results we can state that the ball's overall stiffness grows as the temperature increases.

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Impact of climate change on photochemical air pollution in southern California

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-1561-2009 ◽

2009 ◽

Vol 9 (1) ◽

pp. 1561-1583 ◽

Cited By ~ 3

Author(s):

D. E. Millstein ◽

R. A. Harley

Keyword(s):

Air Quality ◽

Southern California ◽

Reaction Rates ◽

Biogenic Emissions ◽

Western Boundary ◽

Technology Change ◽

Increased Temperature ◽

Time Period ◽

Global Background ◽

Atmospheric Reaction

Abstract. The effects of future climate and emissions-related perturbations on ozone air quality in Southern California are considered, with an assumed increase to 2× pre-industrial levels for global background levels of carbon dioxide. Effects of emission and climate-related forcings on air quality are superimposed on a summer 2005 high-ozone time period. Perturbations considered here include (a) effect of increased temperature on atmospheric reaction rates, (b) effect of increased temperature on biogenic emissions, (c) effect of increased water vapor concentrations, (d) effect of increased pollutant levels at the inflow (western) boundary, and (e) effect of population growth and technology change on emissions within southern California. Various combinations of the above perturbations are also considered. The climate-related perturbations (a–c) led to combined peak 1-h ozone increases of up to 11 ppb. The effect on ozone was greatly reduced when the temperature increase was applied mostly during nighttime hours rather than uniformly throughout the day. Increased pollutant levels at the inflow boundary also led to ozone increases up to 5 ppb. These climate and inflow-related changes offset some of the anticipated benefits of emission controls within the air basin.

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Effect of Elevated Temperatures on Lateral Earth Pressures in Unsaturated Soils

E3S Web of Conferences ◽

10.1051/e3sconf/202019504014 ◽

2020 ◽

Vol 195 ◽

pp. 04014

Author(s):

Sannith Kumar Thota ◽

Farshid Vahedifard

Keyword(s):

Effective Stress ◽

Unsaturated Soils ◽

Elevated Temperatures ◽

Earth Pressure ◽

Effect Of Temperature ◽

Water Retention Curve ◽

Soil Water Retention Curve ◽

Near Surface ◽

Earth Pressures ◽

The Impact

Near-surface unsaturated soils can be exposed to elevated temperatures due to soil-atmospheric interactions under drought events, wildfires, heatwaves, and warm spells, or the heat induced by emerging geotechnical and geo-environmental technologies such as geothermal boreholes and thermally active earthen systems. Elevated temperatures can affect the hydro-mechanical characteristics of unsaturated soils, which in turn can alter lateral earth pressures developed in the backfill soil. The main objective of this study is to quantify the effect of elevated temperatures on active and passive earth pressures of unsaturated soils. For this purpose, the paper presents the derivation of an analytical framework to extend Rankine’s earth pressure theory to account for the effect of temperature under hydrostatic conditions. The equations are derived by incorporating the effect of temperature into the soil water retention curve and a suction stress-based effective stress representation. The proposed effective stress equation considers the temperature-induced changes in the contact angle, surface tension, and enthalpy of immersion. To investigate the impact of temperature on active and passive earth pressures, the proposed method is then used in a set of parametric studies to determine active and passive earth pressure profiles for three hypothetical soils of clay, silt, and sand at different temperatures. Results suggest that elevated temperatures can cause variation in active and passive earth pressures for all the soils considered. The findings of this study can contribute toward analyzing earth retaining structures subjected to elevated temperatures.

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Contribution of emissions to concentrations: The TAGGING 1.0 submodel based on the Modular Earth Submodel System (MESSy 2.52)

10.5194/gmd-2016-298 ◽

2017 ◽

Author(s):

Volker Grewe ◽

Eleni Tsati ◽

Mariano Mertens ◽

Christine Frömming ◽

Patrick Jöckel

Keyword(s):

Air Quality ◽

Tropospheric Ozone ◽

Radiative Forcing ◽

Road Traffic ◽

Computing Time ◽

Reaction Rates ◽

Traffic Emissions ◽

Time Step ◽

Road Traffic Emissions ◽

The Impact

Abstract. Questions such as "What is the contribution of road traffic emissions to climate change?" or "What is the impact of shipping emissions on local air quality?" requires a quantification of the contribution of specific emissions sectors to the concentration of radiatively active species and air quality related species, respectively. Here, we present a diagnostics, implemented in the Modular Earth-System Model MESSy, which keeps track of the contribution of source categories (mainly emission sectors) to various concentrations. The diagnostics is implemented as a submodel (TAGGING) of EMAC (European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry). It determines the contributions of 10 different source categories to the concentration of ozone, nitrogen oxides, peroxyacytyl nitrate, carbon monoxide, non-methane hydrocarbons, hydroxyl and hydroperoxyl radicals (= tagged tracers). The source categories are mainly emission sectors and some other sources for completeness. As emission sectors, road traffic, shipping, air traffic, anthropogenic non-traffic, biogenic, biomass burning, and lightning are considered. The submodel obtains information on the chemical reaction rates, online emissions such as lightning, and wash-out rates. It then solves differential equations for the contribution of a source category to each of the seven tracers. This diagnostics does not feed back to any other part of the model. For the first time, it takes into account chemically competing effects: For example the competition between NOx, CO, and NMHCs in the production and destruction of ozone. We show that the results are in-line with results from other tagging schemes and provide plausibility checks for concentrations of trace gases such as OH and HO2, which have not previously been tagged. The budgets of the tagged tracers, i.e. the contribution from individual source categories (mainly emission sectors) to, e.g., ozone, are only marginally sensitive to changes in model resolution, though the level of detail increases. A reduction in road traffic emissions by 5 % shows that road traffic global tropospheric ozone is reduced by 4 % only, because the net ozone productivity increases. This 4 % reduction in road traffic tropospheric ozone corresponds to a reduction in total tropospheric ozone by &approx; 0.3 %, which is compensated by an increase in tropospheric ozone from other sources by 0.1 %, resulting in a reduction in total tropospheric ozone of &approv; 0.2 %. This compensating effect compares well previous findings. The computational costs of the TAGGING submodel are low with respect to computing time, but a large number of additional tracers are required. The advantage of the tagging scheme is that in one simulation and at every time step and grid point, information is available on the contribution of different emission sectors to the ozone budget, which then can be further used in upcoming studies to calculate the respective radiative forcing simultaneously.

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