The Future? Big Questions about Feedbacks between Anthropogenic Change in the Cryosphere and Atmospheric Chemistry

Abstract. Using a transient simulation for the period 1960–2100 with the state-of-the-art ECHAM5/MESSy Atmospheric Chemistry (EMAC) global model and a tropopause fold identification algorithm, we explore the future projected changes in tropopause folds, stratosphere-to-troposphere transport (STT) of ozone, and tropospheric ozone under the RCP6.0 scenario. Statistically significant changes in tropopause fold frequencies from 1970–1999 to 2070–2099 are identified in both hemispheres, regionally exceeding 3 %, and are associated with the projected changes in the position and intensity of the subtropical jet streams. A strengthening of ozone STT is projected for the future in both hemispheres, with an induced increase in transported stratospheric ozone tracer throughout the whole troposphere, reaching up to 10 nmol mol−1 in the upper troposphere, 8 nmol mol−1 in the middle troposphere, and 3 nmol mol−1 near the surface. Notably, the regions exhibiting the largest changes of ozone STT at 400 hPa coincide with those with the highest fold frequency changes, highlighting the role of the tropopause folding mechanism in STT processes under a changing climate. For both the eastern Mediterranean and Middle East (EMME) and Afghanistan (AFG) regions, which are known as hotspots of fold activity and ozone STT during the summer period, the year-to-year variability of middle-tropospheric ozone with stratospheric origin is largely explained by the short-term variations in ozone at 150 hPa and tropopause fold frequency. Finally, ozone in the lower troposphere is projected to decrease under the RCP6.0 scenario during MAM (March, April, and May) and JJA (June, July, and August) in the Northern Hemisphere and during DJF (December, January, and February) in the Southern Hemisphere, due to the decline of ozone precursor emissions and the enhanced ozone loss from higher water vapour abundances, while in the rest of the troposphere ozone shows a remarkable increase owing mainly to the STT strengthening and the stratospheric ozone recovery.

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Future Shock in Forest Yield Forecasting: The Need for a New Approach

The Forestry Chronicle ◽

10.5558/tfc61503-6 ◽

1985 ◽

Vol 61 (6) ◽

pp. 503-512 ◽

Cited By ~ 10

Author(s):

J. P. Kimmins

Keyword(s):

Forest Management ◽

Acid Rain ◽

Atmospheric Chemistry ◽

Management Practices ◽

Biomass Accumulation ◽

Growth Potential ◽

Stem Volume ◽

Soil Conditions ◽

Yield Model ◽

The Future

The traditional method of predicting future yields of conventional forest products and/or biomass is based on an empirical bioassay of the growth potential of unmanaged stands, or of stands subject to one, or a small number of, management practices. The method employs the historical pattern of stem volume and/or forest biomass accumulation in the form of volume- or biomass-over-age curves. This type of yield predictor, which may be presented as a simple yield table or a more complex mensurational computer yield model, is widely considered to produce believable future yield predictions. However, the predictions will only be accurate if the future environmental conditions and management regimes are similar to those that pertained over the period during which the biomass accumulation on which the yield model is based occurred. This is unlikely because the continued growth of the human population and the resultant loss of forest land will require a great intensification of forest management. The significant changes in management that many believe await forestry in the not-too-distant future in many parts of the world will render such conventional predictions very questionable. In addition, human-induced changes in atmospheric chemistry may result in changes in the climatic (the "green-house gases" problem), canopy or soil conditions (the "acid rain" problem) that determine tree growth.Computer models of forest yield based solely on the simulation of the biological processes that determine tree growth do not at present offer a viable alternative. Either we do not yet know enough to build, or we do not have sufficient resources to develop and calibrate such process models at an adequate level of complexity.What is needed is a generation of hybrid yield models that combine traditional mensurational models with a simulation of those growth-regulating processes that are significantly altered by changing management practices and/or by changing atmospheric chemistry and climate. One such model is FORCYTE: the FORest nutrient Cycling and Yield Trend Evaluator. This is an ecologically-based forest management simulation model that can predict the long-term consequences of a wide variety of forest management practices for the future harvest yield, ecosystem nutrient budgets, economic efficiency and the energy benefit/cost ratio of management. It combines the believability of the traditional approach with the flexibility of ecological and biological process simulation. Present versions of the model focus on the consequences for future production and yield of changes in forest management. However, because of the structure of the model, it is capable of being modified to examine similar consequences of climatic change and alteration in atmospheric chemistry. Progress in the latter area must await clarification of the processes involved in acid rain damage to forests. FORCYTE is also capable, with minor modification, of being used in agriculture and mined land reclamation research and planning. Key words: Yield prediction, FORCYTE.

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Simulation of current and future tropospheric chemistry with the Earth System Model EMAC

10.5194/egusphere-egu2020-21478 ◽

2020 ◽

Author(s):

Oliver Kirner ◽

Jöckel Patrick ◽

Sören Johansson ◽

Gerald Wetzel ◽

Franziska Winterstein

Keyword(s):

Atmospheric Chemistry ◽

Tropospheric Chemistry ◽

Lower Atmosphere ◽

Integrated Modelling ◽

Earth System ◽

Mixing Ratios ◽

The Future ◽

First Results ◽

Acetyl Nitrate ◽

Peroxy Acetyl Nitrate

The increasing future methane (CH4) leads to changes in the lifetime of CH4 and in the Hydroxyl radical (OH) and (O3) mixing ratios and distribution in the lower atmosphere. With increasing CH4 the lifetime of CH4 and the O3 mixing ratios in the troposphere will increase, the tropospheric OH mixing ratios will decrease (Winterstein et al., 2019; Zhao et al., 2019). The CH4 changes, together with the future Nitrous oxide (N2O) and temperature increase, will lead to a different tropospheric chemistry. For example, substances as acetone (CH3COCH3), ethane (C2H6), formic acid (HCOOH) or peroxy acetyl nitrate (PAN) will change their distribution and mixing ratios.In different studies we could show that EMAC (ECHAM/MESSy Atmospheric Chemistry, J&#246;ckel et al., 2010) has the ability to simulate some of the mentioned tropospheric substances in comparison to results of the GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) instrument, used on board of the research aircrafts Geophysica and HALO during the STRATOCLIM (July/August 2017) and WISE (August to October 2017) campaigns (Johansson et al., 2020; Wetzel et al., 2020).&#160; &#160;In this study, we will additional show the first results of the simulated future changes of tropospheric chemistry (especially with focus on CH3COCH3, C2H6, HCOOH and PAN and the upper troposphere) related to the future increase of CH4, N2O and temperature change as a result of climate change. For these we use different EMAC simulations from the project ESCiMo (Earth System Chemistry Integrated Modelling, J&#246;ckel et al., 2016).We will present some results of the comparison of EMAC to GLORIA and results with regard to the future development of the (upper) tropospheric chemistry in EMAC. &#160;&#160;&#160;

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Future changes in surface ozone over the Mediterranean Basin in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-9351-2018 ◽

2018 ◽

Vol 18 (13) ◽

pp. 9351-9373 ◽

Cited By ~ 3

Author(s):

Nizar Jaidan ◽

Laaziz El Amraoui ◽

Jean-Luc Attié ◽

Philippe Ricaud ◽

François Dulac

Keyword(s):

Annual Cycle ◽

Atmospheric Chemistry ◽

Mediterranean Basin ◽

Surface Ozone ◽

Future Climate Change ◽

Ozone Precursors ◽

Ensemble Mean ◽

The Future ◽

The Mediterranean ◽

The Mediterranean Basin

Abstract. In the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr, last access: 22 June 2018) project, we study the evolution of surface ozone over the Mediterranean Basin (MB) with a focus on summertime over the time period 2000–2100, using the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) outputs from 13 models. We consider three different periods (2000, 2030 and 2100) and the four Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) to study the changes in the future ozone and its budget. We use a statistical approach to compare and discuss the results of the models. We discuss the behavior of the models that simulate the surface ozone over the MB. The shape of the annual cycle of surface ozone simulated by ACCMIP models is similar to the annual cycle of the ozone observations, but the model values are biased high. For the summer, we found that most of the models overestimate surface ozone compared to observations over the most recent period (1990–2010). Compared to the reference period (2000), we found a net decrease in the ensemble mean surface ozone over the MB in 2030 (2100) for three RCPs: −14 % (−38 %) for RCP2.6, −9 % (−24 %) for RCP4.5 and −10 % (−29 %) for RCP6.0. The surface ozone decrease over the MB for these scenarios is much more pronounced than the relative changes of the global tropospheric ozone burden. This is mainly due to the reduction in ozone precursors and to the nitrogen oxide (NOx = NO + NO2)-limited regime over the MB. For RCP8.5, the ensemble mean surface ozone is almost constant over the MB from 2000 to 2100. We show how the future climate change and in particular the increase in methane concentrations can offset the benefits from the reduction in emissions of ozone precursors over the MB.

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The Future of Atmospheric Chemistry Research

10.17226/23573 ◽

2016 ◽

Cited By ~ 6

Author(s):

◽

Keyword(s):

Atmospheric Chemistry ◽

Chemistry Research ◽

The Future

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North Atlantic Oscillation model projections and influence on tracer transport

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-33049-2015 ◽

2015 ◽

Vol 15 (22) ◽

pp. 33049-33075 ◽

Cited By ~ 1

Author(s):

S. Bacer ◽

T. Christoudias ◽

A. Pozzer

Keyword(s):

North Atlantic Oscillation ◽

North Atlantic ◽

Atmospheric Chemistry ◽

General Circulation ◽

Decadal Variability ◽

Circulation Model ◽

The Arctic ◽

Spatial And Temporal Variability ◽

Tracer Transport ◽

The Future

Abstract. The North Atlantic Oscillation (NAO) plays an important role in the climate variability of the Northern Hemisphere with significant consequences on pollutant transport. We study the influence of the NAO on the atmospheric dispersion of pollutants in the near past and in the future by considering simulations performed by the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model. We analyze two model runs: a simulation with circulation dynamics nudged towards ERA-Interim reanalysis data over a period of 35 years (1979–2013) and a simulation with prescribed Sea Surface Temperature (SST) boundary conditions over 150 years (1950–2099). The model is shown to reproduce the NAO spatial and temporal variability and to be comparable with observations. We find that the decadal variability in the NAO, which has been pronounced since 1950s until 1990, will continue to dominate in the future considering decadal periods, although no significant trends are present in the long term projection (100–150 years horizon). We do not find in the model projections any significant temporal trend of the NAO for the future, meaning that neither positive or negative phases will dominate. Tracers with idealised decay and emissions are considered to investigate the NAO effects on transport; it is shown that during the positive phase of the NAO, the transport from North America towards northern Europe is stronger and pollutants are shifted northwards over the Arctic and southwards over the Mediterranean and North Africa, with two distinct areas of removal and stagnation of pollutants.

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Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-20975-2012 ◽

2012 ◽

Vol 12 (8) ◽

pp. 20975-21012

Author(s):

Ø. Hodnebrog ◽

T. K. Berntsen ◽

O. Dessens ◽

M. Gauss ◽

V. Grewe ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Radiative Forcing ◽

Road Traffic ◽

North Atlantic Ocean ◽

Lower Troposphere ◽

Traffic Emissions ◽

Transport Sector ◽

Atmospheric Ozone ◽

The Future ◽

The Impact

Abstract. The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B), and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE), presented in a companion paper, and with the recent past (year 2000). Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario. As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000. Radiative Forcing (RF) calculations show that the net effect of AIR, SHIP and ROAD combined will change from a~marginal cooling of −0.38 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 8.9 (B1) or −31 ± 20 mW m−2 (A1B) in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −20 ± 5.4 mW m−2 in 2000 to −31 ± 4.8 (B1) or −40 ± 11 mW m−2 (A1B) in 2050, and from reduced O3 warming from ROAD, which is likely to turn from a positive net RF of 13 ± 7.9 mW m−2 in 2000 to a slightly negative net RF of −2.9 ± 1.7 (B1) or −3.3 ± 3.8 (A1B) mW m−2 in the middle of this century. The negative net RF from ROAD is temporary and induced by the strong decline in ROAD emissions prior to 2050, which only affects the methane cooling term due to the longer lifetime of CH4 compared to O3. The O3 RF from AIR in 2050 is strongly dependent on scenario and ranges from 19 ± 6.8 (B1 ACARE) to 62 ± 13.6 mW m−2 (A1B). There is also a considerable span in the net RF from AIR in 2050, ranging from −0.54 ± 4.6 (B1 ACARE) to 12 ± 11 (A1B) mW m−2 compared to 6.5 ± 2.1 mW m−2 in 2000.

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Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-12211-2012 ◽

2012 ◽

Vol 12 (24) ◽

pp. 12211-12225 ◽

Cited By ~ 10

Author(s):

Ø. Hodnebrog ◽

T. K. Berntsen ◽

O. Dessens ◽

M. Gauss ◽

V. Grewe ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Radiative Forcing ◽

Road Traffic ◽

North Atlantic Ocean ◽

Lower Troposphere ◽

Traffic Emissions ◽

Transport Sector ◽

Atmospheric Ozone ◽

The Future ◽

The Impact

Abstract. The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B), and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE), presented in a companion paper, and with the recent past (year 2000). Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario. As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000. Radiative forcing (RF) calculations show that the net effect of AIR, SHIP and ROAD combined will change from a marginal cooling of −0.44 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 9.3 (B1) or −32 ± 18 mW m−2 (A1B) in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −19 ± 5.3 mW m−2 in 2000 to −31 ± 4.8 (B1) or −40 ± 9 mW m−2 (A1B) in 2050, and from reduced O3 warming from ROAD, which is likely to turn from a positive net RF of 12 ± 8.5 mW m−2 in 2000 to a slightly negative net RF of −3.1 ± 2.2 (B1) or −3.1 ± 3.4 (A1B) mW m−2 in the middle of this century. The negative net RF from ROAD is temporary and induced by the strong decline in ROAD emissions prior to 2050, which only affects the methane cooling term due to the longer lifetime of CH4 compared to O3. The O3 RF from AIR in 2050 is strongly dependent on scenario and ranges from 19 ± 6.8 (B1 ACARE) to 61 ± 14 mW m−2 (A1B). There is also a considerable span in the net RF from AIR in 2050, ranging from −0.54 ± 4.6 (B1 ACARE) to 12 ± 11 (A1B) mW m−2 compared to 6.6 ± 2.2 mW m−2 in 2000.

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Future changes in surface ozone over the Mediterranean basin in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)

10.5194/acp-2017-553 ◽

2017 ◽

Author(s):

Nizar Jaidan ◽

Laaziz El Amraoui ◽

Jean-Luc Attié ◽

Philippe Ricaud ◽

François Dulac

Keyword(s):

Atmospheric Chemistry ◽

Mediterranean Basin ◽

Climate Model ◽

Surface Ozone ◽

Future Climate Change ◽

Ensemble Mean ◽

The Future ◽

The Mediterranean ◽

Surface O3 ◽

The Mediterranean Basin

Abstract. In the framework of the Chemistry and Aerosol Mediterranean Experiment project (ChArMEx, http://charmex.lsce.ipsl.fr), we study the evolution of surface ozone (O3) over the Mediterranean Basin (MB) with a focus on summertime over the time period 2000–2100, using the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) outputs from 11 models. We consider three different periods (2000, 2030 and 2100) and the four Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) to study the changes in the future ozone trend and its budget. We use a statistical approach to compare and discuss the results of the models. We discuss the behavior of the models that simulate the surface O3 over the MB. The ensemble mean of ACCMIP models simulates very well the annual cycle of surface O3. Compared to measured summer surface O3 datasets, we found that most of the models overestimate surface O3 and underestimate its variability over the most recent period (1990–2010) when independent observations are available. Compared to the reference period (2000), we found a net decrease in the ensemble mean surface O3 over the MB in 2030 (2100) for 3 RCPs: −13 % (−36 %) for RCP2.6, −7 % (−22 %) for RCP4.5 and −11 % (−33 %) for RCP6.0. The surface O3 decrease over the MB for these scenarios is much more pronounced than the relative changes of the tropospheric ozone burden. This is mainly due to the reduction in O3 precursors and to the NOx-limited regime over the MB. For the RCP8.5, the ensemble mean surface O3 is almost constant over the MB from 2000 to 2100. We show how the future climate change and the increase in CH4 concentrations can offset the benefit of the reduction in emissions of O3 precursors over the MB.

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