Impacts of increased anthropogenic emissions in Asia on tropospheric ozone and climate. A global 3-D model study

Abstract. A system for source attribution of tropospheric ozone produced from both NOx and volatile organic compound (VOC) precursors is described, along with its implementation in the Community Earth System Model (CESM) version 1.2.2 using CAM4. The user can specify an arbitrary number of tag identities for each NOx or VOC species in the model, and the tagging system rewrites the model chemical mechanism and source code to incorporate tagged tracers and reactions representing these tagged species, as well as ozone produced in the stratosphere. If the user supplies emission files for the corresponding tagged tracers, the model will produce tagged ozone tracers which represent the contribution of each of the tag identities to the modelled total tropospheric ozone. Our tagged tracers preserve Ox. The size of the tagged chemical mechanism scales linearly with the number of specified tag identities. Separate simulations are required for NOx and VOC tagging, which avoids the sharing of tag identities between NOx and VOC species. Results are presented and evaluated for both NOx and VOC source attribution. We show that northern hemispheric surface ozone is dominated year-round by anthropogenic emissions of NOx, but that the mix of corresponding VOC precursors changes over the course of the year; anthropogenic VOC emissions contribute significantly to surface ozone in winter–spring, while biogenic VOCs are more important in summer. The system described here can provide important diagnostic information about modelled ozone production, and could be used to construct source–receptor relationships for tropospheric ozone.

Download Full-text

Simulation of the interannual variations of tropospheric ozone over China: Roles of variations in meteorological parameters and anthropogenic emissions

Atmospheric Environment ◽

10.1016/j.atmosenv.2015.08.081 ◽

2015 ◽

Vol 122 ◽

pp. 839-851 ◽

Cited By ~ 25

Author(s):

Sijia Lou ◽

Hong Liao ◽

Yang Yang ◽

Qing Mu

Keyword(s):

Tropospheric Ozone ◽

Meteorological Parameters ◽

Anthropogenic Emissions ◽

Interannual Variations

Download Full-text

Influence of future climate and cropland expansion on isoprene emissions and tropospheric ozone

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-1011-2014 ◽

2014 ◽

Vol 14 (2) ◽

pp. 1011-1024 ◽

Cited By ~ 23

Author(s):

O. J. Squire ◽

A. T. Archibald ◽

N. L. Abraham ◽

D. J. Beerling ◽

C. N. Hewitt ◽

...

Keyword(s):

Climate Change ◽

Land Use ◽

Land Use Change ◽

21St Century ◽

Tropospheric Ozone ◽

Climate Model ◽

Anthropogenic Emissions ◽

Change Scenario ◽

Dynamic Global Vegetation Model ◽

The Tropics

Abstract. Over the 21st century, changes in CO2 levels, climate and land use are expected to alter the global distribution of vegetation, leading to changes in trace gas emissions from plants, including, importantly, the emissions of isoprene. This, combined with changes in anthropogenic emissions, has the potential to impact tropospheric ozone levels, which above a certain level are harmful to animals and vegetation. In this study we use a biogenic emissions model following the empirical parameterisation of the MEGAN model, with vegetation distributions calculated by the Sheffield Dynamic Global Vegetation Model (SDGVM) to explore a range of potential future (2095) changes in isoprene emissions caused by changes in climate (including natural land use changes), land use, and the inhibition of isoprene emissions by CO2. From the present-day (2000) value of 467 Tg C yr−1, we find that the combined impact of these factors could cause a net decrease in isoprene emissions of 259 Tg C yr−1 (55%) with individual contributions of +78 Tg C yr−1 (climate change), −190 Tg C yr−1 (land use) and −147 Tg C yr−1 (CO2 inhibition). Using these isoprene emissions and changes in anthropogenic emissions, a series of integrations is conducted with the UM-UKCA chemistry-climate model with the aim of examining changes in ozone over the 21st century. Globally, all combined future changes cause a decrease in the tropospheric ozone burden of 27 Tg (7%) from 379 Tg in the present-day. At the surface, decreases in ozone of 6–10 ppb are calculated over the oceans and developed northern hemispheric regions, due to reduced NOx transport by PAN and reductions in NOx emissions in these areas respectively. Increases of 4–6 ppb are calculated in the continental tropics due to cropland expansion in these regions, increased CO2 inhibition of isoprene emissions, and higher temperatures due to climate change. These effects outweigh the decreases in tropical ozone caused by increased tropical isoprene emissions with climate change. Our land use change scenario consists of cropland expansion, which is most pronounced in the tropics. The tropics are also where land use change causes the greatest increases in ozone. As such there is potential for increased crop exposure to harmful levels of ozone. However, we find that these ozone increases are still not large enough to raise ozone to such damaging levels.

Download Full-text

Halogen chemistry reduces tropospheric O<sub>3</sub> radiative forcing

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-1557-2017 ◽

2017 ◽

Vol 17 (2) ◽

pp. 1557-1569 ◽

Cited By ~ 22

Author(s):

Tomás Sherwen ◽

Mat J. Evans ◽

Lucy J. Carpenter ◽

Johan A. Schmidt ◽

Loretta J. Mickley

Keyword(s):

Tropospheric Ozone ◽

Radiative Forcing ◽

Observational Evidence ◽

Anthropogenic Emissions ◽

Transport Models ◽

Model Calculations ◽

Halogen Chemistry ◽

Tropospheric O3 ◽

Observational Record ◽

Surface O3

Abstract. Tropospheric ozone (O3) is a global warming gas, but the lack of a firm observational record since the preindustrial period means that estimates of its radiative forcing (RFTO3) rely on model calculations. Recent observational evidence shows that halogens are pervasive in the troposphere and need to be represented in chemistry-transport models for an accurate simulation of present-day O3. Using the GEOS-Chem model we show that tropospheric halogen chemistry is likely more active in the present day than in the preindustrial. This is due to increased oceanic iodine emissions driven by increased surface O3, higher anthropogenic emissions of bromo-carbons, and an increased flux of bromine from the stratosphere. We calculate preindustrial to present-day increases in the tropospheric O3 burden of 113 Tg without halogens but only 90 Tg with, leading to a reduction in RFTO3 from 0.43 to 0.35 Wm−2. We attribute ∼ 50 % of this reduction to increased bromine flux from the stratosphere, ∼ 35 % to the ocean–atmosphere iodine feedback, and ∼ 15 % to increased tropospheric sources of anthropogenic halogens. This reduction of tropospheric O3 radiative forcing due to halogens (0.087 Wm−2) is greater than that from the radiative forcing of stratospheric O3 (∼ 0.05 Wm−2). Estimates of RFTO3 that fail to consider halogen chemistry are likely overestimates (∼ 25 %).

Download Full-text

The size of the supraspinatus outlet during elevation of the arm in the frontal and sagittal plane: a 3-D model study

Clinical Biomechanics ◽

10.1016/s0268-0033(02)00021-9 ◽

2002 ◽

Vol 17 (4) ◽

pp. 257-266 ◽

Cited By ~ 8

Author(s):

Carel G.M. Meskers ◽

Frans C.T. van der Helm ◽

Piet M. Rozing

Keyword(s):

Sagittal Plane ◽

Model Study ◽

D Model

Download Full-text

Late-Spring and Summertime Tropospheric Ozone and NO<sub>2</sub> in Western Siberia and the Russian Arctic: Regional Model Evaluation and Sensitivities

10.5194/acp-2020-426 ◽

2020 ◽

Author(s):

Thomas Thorp ◽

Stephen R. Arnold ◽

Richard J. Pope ◽

Dominic V. Spracklen ◽

Luke Conibear ◽

...

Keyword(s):

Dry Deposition ◽

Tropospheric Ozone ◽

Western Siberia ◽

Surface Ozone ◽

Late Spring ◽

The Arctic ◽

Transport Sector ◽

Anthropogenic Emissions ◽

Negative Bias ◽

Russian Arctic

Abstract. We use a regional chemistry transport model (WRF-Chem) in conjunction with surface observations of tropospheric ozone and Ozone Monitoring Instrument (OMI) satellite retrievals of tropospheric column NO2 to evaluate processes controlling the regional distribution of tropospheric ozone over Western Siberia for late-spring and summer in 2011. This region hosts a range of anthropogenic and natural ozone precursor sources, and serves as a gateway for near-surface transport of Eurasian pollution to the Arctic. However, there is a severe lack of in-situ observations to constrain tropospheric ozone sources and sinks in the region. We show widespread negative bias in WRF-Chem tropospheric column NO2 when compared to OMI satellite observations from May – August, which is reduced when using ECLIPSE v5a emissions (FMB= -0.82 to -0.73) compared with the EDGAR-HTAP-2 emissions data (FMB= -0.80 to -0.70). Despite the large negative bias, the spatial correlations between model and observed NO2 columns suggest that the spatial pattern of NOx sources in the region is well represented. Based on ECLIPSE v5a emissions, we assess the influence of the two dominant anthropogenic emission sectors (transport and energy) and vegetation fires on surface NOx and ozone over Siberia and the Russian Arctic. Our results suggest regional ozone is more sensitive to anthropogenic emissions, particularly from the transport sector, and the contribution from fire emissions maximises in June and is largely confined to latitudes south of 60° N. Large contributions to surface ozone from energy emissions are simulated in April north of 60° N, due to emissions associated with oil and gas extraction. Ozone dry deposition fluxes from the model simulations show that the dominant ozone dry deposition sink in the region is to forest, averaging 6.0 Tg of ozone per month, peaking at 9.1 Tg of ozone deposition during June. The impact of fires on ozone dry deposition within the domain is small compared to anthropogenic emissions, and is negligible north of 60° N. Overall, our results suggest that surface ozone in the region is controlled by an interplay between seasonality in atmospheric transport patterns, vegetation dry deposition, and a dominance of transport and energy sector emissions.

Download Full-text

Tracking Tropospheric Ozone Since 1979

Eos ◽

10.1029/2020eo143675 ◽

2020 ◽

Vol 101 ◽

Author(s):

David Shultz

Keyword(s):

Ozone Depletion ◽

Tropospheric Ozone ◽

Stratospheric Ozone ◽

Ozone Production ◽

Anthropogenic Emissions ◽

Stratospheric Ozone Depletion

Stratospheric ozone depletion between 1979 and 2010 resulted in a slight decrease of ozone in the troposphere during that period despite increased ozone production from anthropogenic emissions.

Download Full-text