scholarly journals Projected global tropospheric ozone impacts on vegetation under different emission and climate scenarios

2017 ◽  
Author(s):  
Pierre Sicard ◽  
Alessandro Anav ◽  
Alessandra De Marco ◽  
Elena Paoletti
Keyword(s):  
Atmospheric Chemistry ◽  
High Surface ◽  
Central Africa ◽  
Ground Level ◽  
Global Scale ◽  
Climate Modelling ◽  
North Asia ◽  
Vegetation Models ◽  
The Impact ◽  
Surface O3

Abstract. The impact of ground-level ozone (O3) on vegetation is largely under-investigated at global scale despite worldwide large areas are exposed to high surface O3 levels and concentrations are expected to increase in the next future. To explore future potential impacts of O3 on vegetation, we compared historical and projected O3 concentrations simulated by six global atmospheric chemistry transport models on the basis of three representative concentration pathways emission scenarios (i.e. RCP2.6, 4.5, 8.5). To assess changes in the potential O3 threat to vegetation, we used the AOT40 metric. Results point out a significant overrun of AOT40 in comparison with the recommendations of UNECE for the protection of vegetation. In fact, many areas of the northern hemisphere show that AOT40-based critical levels will be exceeded by a factor of at least 10 under RCP8.5. Changes in surface O3 by 2100 range from about +4–5 ppb worldwide in RCP8.5 scenario to reductions of about 2–10 ppb in the RCP2.6 scenario. The risk of O3 injury for vegetation decreased by 61 % and 47 % under RCP2.6 and RCP4.5, respectively and increased by 70 % under RCP8.5. Key biodiversity areas in South and North Asia, central Africa and Northern America were identified as being at risk from high O3 concentrations. To better evaluate the regional exposure of ecosystems to O3 pollution, we recommend the use of improved chemistry-climate modelling system, fully coupled with dynamic vegetation models.

scholarly journals Projected global ground-level ozone impacts on vegetation under different emission and climate scenarios

2017 ◽  
Vol 17 (19) ◽  
pp. 12177-12196 ◽  
Author(s):  
Pierre Sicard ◽  
Alessandro Anav ◽  
Alessandra De Marco ◽  
Elena Paoletti
Keyword(s):  
Atmospheric Chemistry ◽  
High Surface ◽  
Central Africa ◽  
Ground Level ◽  
Global Scale ◽  
Northern Asia ◽  
Ground Level Ozone ◽  
Photosynthetic Assimilation ◽  
The Impact ◽  
Surface O3

Abstract. The impact of ground-level ozone (O3) on vegetation is largely under-investigated at the global scale despite large areas worldwide that are exposed to high surface O3 levels. To explore future potential impacts of O3 on vegetation, we compared historical and projected surface O3 concentrations simulated by six global atmospheric chemistry transport models on the basis of three representative concentration pathways emission scenarios (i.e. RCP2.6, 4.5, 8.5). To assess changes in the potential surface O3 threat to vegetation at the global scale, we used the AOT40 metric. Results point out a significant exceedance of AOT40 in comparison with the recommendations of UNECE for the protection of vegetation. In fact, many areas of the Northern Hemisphere show that AOT40-based critical levels will be exceeded by a factor of at least 10 under RCP8.5. Changes in surface O3 by 2100 worldwide range from about +4–5 ppb in the RCP8.5 scenario to reductions of about 2–10 ppb in the most optimistic scenario, RCP2.6. The risk of O3 injury for vegetation, through the potential O3 impact on photosynthetic assimilation, decreased by 61 and 47 % under RCP2.6 and RCP4.5, respectively, and increased by 70 % under RCP8.5. Key biodiversity areas in southern and northern Asia, central Africa and North America were identified as being at risk from high O3 concentrations.

scholarly journals Simulating Lightning NO<sub>X</sub> Production in CMAQv5.2 Using mNLDN, hNLDN, and pNLDN Schemes: Performance Evaluation

2019 ◽  
Author(s):  
Daiwen Kang ◽  
Kristen Foley ◽  
Rohit Mathur ◽  
Shawn Roselle ◽  
Kenneth Pickering ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Wet Deposition ◽  
Monitoring Network ◽  
Ground Level ◽  
Daily Maximum ◽  
Lightning Flash ◽  
Vertical Profiles ◽  
Model Predictions ◽  
The Impact ◽  
Surface O3

Abstract. This study assesses the impact of the lightning NOX (LNOX) production schemes in the CMAQ model (Kang et al., 2019) on ground-level air quality as well as aloft atmospheric chemistry through detailed evaluation of model predictions of nitrogen oxides (NOx) and ozone (O3) with corresponding observations for the U.S. For ground-level evaluations, hourly O3 and NOx from the US EPA's AQS monitoring network are used to assess the impact of different LNOx schemes on model prediction of these species in time and space. Vertical evaluations are performed using ozonesonde and P-3B aircraft measurements during the DISCOVER-AQ campaign conducted in the Baltimore/Washington region during July 2011. The impact on wet deposition of nitrate is assessed using measurements from the National Atmospheric Deposition Program's National Trends Network (NADP/NTN). Compared with the base model (without LNOx), the impact of LNOx on surface O3 varies from region to region depending on the base model conditions. Overall statistics suggest that for regions where surface O3 mixing ratios are already overestimated, the incorporation of additional NOx from lightning generally increased model overestimation of mean daily maximum 8-hr (DM8HR) O3 by 1–2 ppb. In regions where surface O3 is underestimated by the base model, LNOx can significantly reduce the underestimation and bring model predictions close to observations. Analysis of vertical profiles reveals that LNOx can significantly improve the vertical structure of modeled O3 distributions by reducing underestimation aloft, and to a lesser degree decreasing overestimation near the surface. Since the base model underestimates the wet deposition of nitrate in most regions across the modeling domain except the Pacific Coast, the inclusion of LNOx leads to reduction in biases and errors and an increase in correlation coefficients at almost all the NADP/NTN sites. Among the three LNOx schemes described in Kang et al. (2019), the hNLDN scheme, which is implemented using hourly observed lightning flash data from National Lightning Detection Network (NLDN), performs best for the ground-level, vertical profiles, and wet deposition comparisons except that for the accumulated wet deposition of nitrate, the mNLDN scheme (the monthly NLDN-based scheme) performed slightly better. However, when observed lightning flash data are not available, the linear regression-based parameterization scheme, pNLDN, provides an improved estimate for LNOx compared to the base simulation that does not include LNOx.

scholarly journals Atmospheric Mercury Concentrations observed at ground-based monitoring sites globally distributed in the framework of the GMOS network

2016 ◽  
Author(s):  
Francesca Sprovieri ◽  
Nicola Pirrone ◽  
Mariantonia Bencardino ◽  
Francesco D’Amore ◽  
Francesco Carbone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Ad Hoc ◽  
Temporal Trends ◽  
Global Scale ◽  
Atmospheric Mercury ◽  
Global Network ◽  
Observation System ◽  
Large Network ◽  
Deposition Processes ◽  
The Impact

Abstract. Long-term monitoring data of ambient mercury (Hg) on a global scale to assess its emission, transport, atmospheric chemistry, and deposition processes is vital to understanding the impact of Hg pollution on the environment. The Global Mercury Observation System (GMOS) project was funded by the European Commission (www.gmos.eu), and started in November 2010 with the overall goal to develop a coordinated global observing system to monitor Hg on a global scale, including a large network of ground-based monitoring stations, ad-hoc periodic oceanographic cruises and measurement flights in the lower and upper troposphere, as well as in the lower stratosphere. To date more than 40 ground-based monitoring sites constitute the global network covering many regions where little to no observational data were available before GMOS. This work presents atmospheric Hg concentrations recorded worldwide in the framework of the GMOS project (2010–2015), analyzing Hg measurement results in terms of temporal trends, seasonality and comparability within the network. Major findings highlighted in this paper include a clear gradient of Hg concentrations between the Northern and Southern Hemisphere, confirming that the gradient observed is mostly driven by local and regional sources, which can be anthropogenic, natural or a combination of both.

scholarly journals Evaluation of a Global Vegetation Model using time series of satellite vegetation indices

2011 ◽  
Vol 4 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
F. Maignan ◽  
F.-M. Bréon ◽  
F. Chevallier ◽  
N. Viovy ◽  
P. Ciais ◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Vegetation Index ◽  
Vegetation Indices ◽  
Global Scale ◽  
Vegetation Dynamic ◽  
Rate Of Increase ◽  
Vegetation Models ◽  
Global Vegetation ◽  
The Impact

Abstract. Atmospheric CO2 drives most of the greenhouse effect increase. One major uncertainty on the future rate of increase of CO2 in the atmosphere is the impact of the anticipated climate change on the vegetation. Dynamic Global Vegetation Models (DGVM) are used to address this question. ORCHIDEE is such a DGVM that has proven useful for climate change studies. However, there is no objective and methodological way to accurately assess each new available version on the global scale. In this paper, we submit a methodological evaluation of ORCHIDEE by correlating satellite-derived Vegetation Index time series against those of the modeled Fraction of absorbed Photosynthetically Active Radiation (FPAR). A perfect correlation between the two is not expected, however an improvement of the model should lead to an increase of the overall performance. We detail two case studies in which model improvements are demonstrated, using our methodology. In the first one, a new phenology version in ORCHIDEE is shown to bring a significant impact on the simulated annual cycles, in particular for C3 Grasses and C3 Crops. In the second case study, we compare the simulations when using two different weather fields to drive ORCHIDEE. The ERA-Interim forcing leads to a better description of the FPAR interannual anomalies than the simulation forced by a mixed CRU-NCEP dataset. This work shows that long time series of satellite observations, despite their uncertainties, can identify weaknesses in global vegetation models, a necessary first step to improving them.

Variability in modelled airborne dust mineralogy derived from global soil composition uncertainties

2021 ◽  
Author(s):  
María Gonçalves Ageitos ◽  
Matt Dawson ◽  
Vincenzo Obiso ◽  
Martina Klose ◽  
Ron Miller ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Biogeochemical Cycles ◽  
Wave Radiation ◽  
Climate Modelling ◽  
Soil Composition ◽  
Soil Mineralogy ◽  
Airborne Dust ◽  
Global Soil ◽  
Dust Composition ◽  
The Impact

&lt;p&gt;Dust aerosols consist on a variety of minerals with different physic and chemical properties. As such, they interact with short and long wave radiation, potentially form clouds, act as nutrients modulating biogeochemical cycles, or influence atmospheric chemistry, differently. Most current state-of-the-art Earth System Models (ESMs) neglect the complexity in dust composition, mainly due to computational constraints, but also to the existing uncertainties in the size resolved composition of parent soils, the resulting distribution of minerals in airborne dust, and the scarcity of observations to constrain them.&lt;/p&gt;&lt;p&gt;Within this work, we assess the variability of global dust composition due to uncertainties in the characterization of the parent soil mineralogy. To that end, we consider two available global soil mineralogy atlases, developed by Claquin et al. (1999) &amp;#8211;C1999- and Journet et al. (2014) &amp;#8211;J2014-, which represent respectively 8 and 12 relevant minerals for climate (namely: illite, smectite/montmorillonite, kaolinite, calcite, gypsum, hematite, quartz, and feldspars in C1999, and those plus chlorite, vermiculite, goethite, and mica in J2014). Thanks to a recently developed feature of the MONARCH atmospheric-chemistry model, we are able to explicitly resolve the minerals&amp;#8217; atmospheric cycle. Therefore, we define two global experiments to assess changes on airborne dust composition attributed to the soil mineralogy assumptions and provide a measure of their variability. We also perform a preliminary evaluation of the global mineralogy results against available observations of mineral fractions in surface dust concentration.&lt;/p&gt;&lt;p&gt;Our results will inform the climate modelling community about the potential variability in dust composition, an aspect that will gain relevance as ESMs continue growing in complexity and new processes to better characterize aerosols&amp;#8217; forcing or biogeochemical cycles are added. Further observational constraints, such as those that will derive from the EMIT NASA mission on soil composition or the FRAGMENT experimental campaigns on airborne dust characterization, will be key in the near future to improve our understanding of the impact of dust mineralogy on fundamental climate features.&lt;/p&gt;

scholarly journals Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

2013 ◽  
Vol 13 (19) ◽  
pp. 9917-9937 ◽  
Author(s):  
R. Locatelli ◽  
P. Bousquet ◽  
F. Chevallier ◽  
A. Fortems-Cheney ◽  
S. Szopa ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Transport Model ◽  
Initial Conditions ◽  
Spatial Scales ◽  
Global Scale ◽  
Methane Emissions ◽  
Inverse Modelling ◽  
Model Errors ◽  
Inverse Systems ◽  
The Impact

Abstract. A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System) inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure) is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr−1 at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr−1 in North America to 7 Tg yr−1 in Boreal Eurasia (from 23 to 48%, respectively). At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly question the consistency of transport model errors in current inverse systems. Future inversions should include more accurately prescribed observation covariances matrices in order to limit the impact of transport model errors on estimated methane fluxes.

scholarly journals The 1-way on-line coupled model system MECO(n) – Part 4: Chemical evaluation (based on MESSy v2.52)

2016 ◽  
Author(s):  
Mariano Mertens ◽  
Astrid Kerkweg ◽  
Patrick Jöckel ◽  
Holger Tost ◽  
Christiane Hofmann
Keyword(s):  
Atmospheric Chemistry ◽  
Coupled Model ◽  
Ground Level ◽  
Global Scale ◽  
Model System ◽  
Scale Down ◽  
On Line ◽  
In Situ Observations ◽  
Line Coupling

Abstract. For the first time a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSyfied ECHAM and COSMO model nested n-times. It features an on-line coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called COSMO/MESSy), with the global atmospheric chemistry model ECHAM5/MESSy for Atmospheric Chemistry (EMAC). This on-line coupling allows a consistent model chain with respect to chemical and meteorological boundary conditions from the global scale down to the regional kilometre scale. A MECO(2) simulation incorporating one regional instance over Europe with 50 km resolution and a one instance over Germany with 12 km resolution is conducted for the evaluation of MECO(n) with respect to tropospheric gas-phase chemistry. The main goal of this evaluation is to ensure, that the chemistry related MESSy submodels and the on-line coupling with respect to the chemistry are correctly implemented. This evaluation is a prerequisite for the further usage of MECO(n) in atmospheric chemistry related studies. Results of EMAC and the two COSMO/MESSy instances are compared with satellite-, ground-based- and aircraft in situ observations, focusing on ozone, carbon monoxide and nitrogen dioxide. Further the methane lifetimes in EMAC and the two COSMO/MESSy instances are analysed in view of the tropospheric oxidation capacity. From this evaluation we conclude that the chemistry related submodels and the on-line coupling with respect to the chemistry are correctly implemented. In comparison with observations both, EMAC and COSMO/MESSy, show strengths and weaknesses. Especially in comparison to aircraft in situ observations COSMO/MESSy shows very promising results. However, the amplitude of the diurnal cycle of ground-level ozone measurements is underestimated. Most of the differences between COSMO/MESSy and EMAC can be attributed to differences in the dynamics of both models, which is subject to further model developments.

scholarly journals The 1-way on-line coupled model system MECO(n) – Part 4: Chemical evaluation (based on MESSy v2.52)

2016 ◽  
Vol 9 (10) ◽  
pp. 3545-3567 ◽  
Author(s):  
Mariano Mertens ◽  
Astrid Kerkweg ◽  
Patrick Jöckel ◽  
Holger Tost ◽  
Christiane Hofmann
Keyword(s):  
Atmospheric Chemistry ◽  
Coupled Model ◽  
Ground Level ◽  
Global Scale ◽  
Model System ◽  
Scale Down ◽  
On Line ◽  
In Situ Observations ◽  
Phase Chemistry

Abstract. For the first time, a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSy-fied ECHAM and COSMO models nested n times. It features an online coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called COSMO/MESSy), with the global atmospheric chemistry model ECHAM5/MESSy for Atmospheric Chemistry (EMAC). This online coupling allows a consistent model chain with respect to chemical and meteorological boundary conditions from the global scale down to the regional kilometre scale. A MECO(2) simulation incorporating one regional instance over Europe with 50 km resolution and one instance over Germany with 12 km resolution is conducted for the evaluation of MECO(n) with respect to tropospheric gas-phase chemistry. The main goal of this evaluation is to ensure that the chemistry-related MESSy submodels and the online coupling with respect to the chemistry are correctly implemented. This evaluation is a prerequisite for the further usage of MECO(n) in atmospheric chemistry-related studies. Results of EMAC and the two COSMO/MESSy instances are compared with satellite, ground-based and aircraft in situ observations, focusing on ozone, carbon monoxide and nitrogen dioxide. Further, the methane lifetimes in EMAC and the two COSMO/MESSy instances are analysed in view of the tropospheric oxidation capacity. From this evaluation, we conclude that the chemistry-related submodels and the online coupling with respect to the chemistry are correctly implemented. In comparison with observations, both EMAC and COSMO/MESSy show strengths and weaknesses. Especially in comparison to aircraft in situ observations, COSMO/MESSy shows very promising results. However, the amplitude of the diurnal cycle of ground-level ozone measurements is underestimated. Most of the differences between COSMO/MESSy and EMAC can be attributed to differences in the dynamics of both models, which are subject to further model developments.

scholarly journals The impact of ice uptake of nitric acid on atmospheric chemistry

2006 ◽  
Vol 6 (1) ◽  
pp. 225-235 ◽  
Author(s):  
R. von Kuhlmann ◽  
M. G. Lawrence
Keyword(s):  
Atmospheric Chemistry ◽  
Transport Model ◽  
Global Scale ◽  
Large Set ◽  
Model Match ◽  
Uptake Process ◽  
Significant Uptake ◽  
The Impact ◽  
Experimental And Theoretical Studies

Abstract. The potential impact of the uptake of HNO3 on ice on the distribution of NOy species, ozone and OH has been assessed using the global scale chemistry-transport model MATCH-MPIC. Assuming equilibrium uptake according to dissociative Langmuir theory results in significant reductions of gas phase HNO3. Comparison to a large set of observations provides support that significant uptake of HNO3 on ice is occurring, but the degree of the uptake cannot be inferred from this comparison alone. Sensitivity simulations show that the uncertainties in the total amount of ice formation in the atmosphere and the actual expression of the settling velocity of ice particles only result in small changes in our results. The largest uncertainty is likely to be linked to the actual theory describing the uptake process and the value of the initial uptake coefficient. The inclusion of non-methane hydrocarbon chemistry partially compensates for the absence of HNO3 uptake on ice when this is neglected in the model. The calculated overall effect on upper tropospheric ozone concentrations and the tropospheric methane lifetime are moderate to low. These results support a shift in the motivation for future experimental and theoretical studies of HNO3-ice interaction towards the role of HNO3 in hydrometeor surface physics.

scholarly journals Assessing the Country-Level Excess All-Cause Mortality and the Impacts of Air Pollution and Human Activity during the COVID-19 Epidemic

2021 ◽  
Vol 18 (13) ◽  
pp. 6883
Author(s):  
Yuan Meng ◽  
Man Sing Wong ◽  
Hanfa Xing ◽  
Mei-Po Kwan ◽  
Rui Zhu
Keyword(s):  
Air Pollution ◽  
Human Activity ◽  
Human Activities ◽  
Ground Level ◽  
Global Scale ◽  
Country Level ◽  
Relative Risks ◽  
All Cause Mortality ◽  
Specific Mortality ◽  
The Impact

The impact of Coronavirus Disease 2019 (COVID-19) on cause-specific mortality has been investigated on a global scale. However, less is known about the excess all-cause mortality and air pollution-human activity responses. This study estimated the weekly excess all-cause mortality during COVID-19 and evaluated the impacts of air pollution and human activities on mortality variations during the 10th to 52nd weeks of 2020 among sixteen countries. A SARIMA model was adopted to estimate the mortality benchmark based on short-term mortality during 2015–2019 and calculate excess mortality. A quasi-likelihood Poisson-based GAM model was further applied for air pollution/human activity response evaluation, namely ground-level NO2 and PM2.5 and the visit frequencies of parks and workplaces. The findings showed that, compared with COVID-19 mortality (i.e., cause-specific mortality), excess all-cause mortality changed from −26.52% to 373.60% during the 10th to 52nd weeks across the sixteen countries examined, revealing higher excess all-cause mortality than COVID-19 mortality in most countries. For the impact of air pollution and human activities, the average country-level relative risk showed that one unit increase in weekly NO2, PM2.5, park visits and workplace visits was associated with approximately 1.54% increase and 0.19%, 0.23%, and 0.23% decrease in excess all-cause mortality, respectively. Moreover, compared with the impact on COVID-19 mortality, the relative risks of weekly NO2 and PM2.5 were lower, and the relative risks of weekly park and workplace visits were higher for excess all-cause mortality. These results suggest that the estimation based on excess all-cause mortality reduced the potential impact of air pollution and enhanced the influence of human activities compared with the estimation based on COVID-19 mortality.

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