Effects of 1997 Indonesian forest fires on tropospheric ozone enhancement, radiative forcing, and temperature change over the Hong Kong region

Chan, Chia-Tai; Chan, L. Y.; Zheng, Y. G.; Harris, Joyce M.; Oltmans, S. J.; Christopher, Sundar A.

doi:10.1029/2001jd900092

Cited by 22 publications

(24 citation statements)

References 33 publications

(16 reference statements)

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“…This is comparable with 0.022 W m −2 per ppb O 3 that we computed from observational data (IPCC 2001) that correlate changes in mean tropospheric O 3 column with radiative forcing. The RTM test also shows that, for example, a change of 20 ppb in near-surface O 3 imparts a 0.4 W m −2 radiativeforcing effect locally, which is consistent in order of magnitude with the effects of observed tropospheric ozone enhancements, e.g., as reported by Chan et al (2001).…”

Section: Stand-alone Rtm Testssupporting

confidence: 72%

Evaluating the Effects of Radiative Forcing Feedback in Modelling Urban Ozone Air Quality in Portland, Oregon: Two-Way Coupled MM5–CMAQ Numerical Model Simulations

Taha¹,

Sailor

2010

Boundary-Layer Meteorol

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We summarize an on-line coupled meteorological-emissions-photochemical modelling system that allows feedback from air-quality/chemistry to meteorology via radiative forcing. We focus on the radiative-forcing impacts (direct effects) of ozone. We present an application of the coupled modelling system to the episode of 23-31 July 1998 in Portland, Oregon, U.S.A. Results suggest that the inclusion of radiative-forcing feedback produces small but accountable impacts. For this region and episode, stand-alone radiative transfer simulations, i.e., evaluating the effects of radiative forcing independently of changes in meteorology or emissions, suggest that a change of 1 ppb in ground-level ozone is approximately equivalent to a change of 0.017 W m −2 in radiative forcing. In on-line, coupled, three-dimensional simulations, where the meteorological dependencies are accounted for, domain-wide peak ozone concentrations were higher by 2-4 ppb (relative to a simulated peak of 119.4 ppb) when including the effects of radiative-forcing feedback. A scenario of 10% reduction in anthropogenic emissions produced slightly larger decreases in ozone, an additional 1 ppb in local-peak reductions, relative to scenarios without feedback. Background and Study GoalWe can depict in abstract terms (relations 1 and 2) the meteorology-to-chemistry and chemistry-to-meteorology feedbacks of interest in this study and their implications (listed above the brackets) in meteorological and air-quality modelling, viz.

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Section: Stand-alone Rtm Testssupporting

confidence: 72%

Evaluating the Effects of Radiative Forcing Feedback in Modelling Urban Ozone Air Quality in Portland, Oregon: Two-Way Coupled MM5–CMAQ Numerical Model Simulations

Taha¹,

Sailor

2010

Boundary-Layer Meteorol

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“…This rapid increase in CO emission was not taken into account in the MOPITT simulation, which can partially explain the underestimation of the CO column (Zhao et al, 2006). The largest deviation (34.1%) was an underestimation in April; it may have been caused by the underestimation of biomass burning emissions of CO in local or upwind areas (e.g., Southeast Asia) during spring (Chan et al, 2001;Zhao et al, 2010;Nam et al, 2010;Hecobian et al, 2011). Vegetation burning is influential in spring in Southeast Asia and has a significant effect on tropospheric CO during this season (Liu et al, 1999;Dwyer et al, 2000;Heil and Goldammer, 2001).…”

Section: Comparisons Of Mozart and Mopitt Carbon Monoxidementioning

confidence: 80%

Impacts of global emissions of CO, NO x , and CH4 on China tropospheric hydroxyl free radicals

Lin

Fan³

et al. 2012

Adv. Atmos. Sci.

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Using the global chemistry and transport model MOZART, the simulated distributions of tropospheric hydroxyl free radicals (OH) over China and its sensitivities to global emissions of carbon monoxide (CO), nitrogen oxide (NOx), and methane (CH4) were investigated in this study. Due to various distributions of OH sources and sinks, the concentrations of tropospheric OH in east China are much greater than in west China. The contribution of NO + perhydroxyl radical (HO2) reaction to OH production in east China is more pronounced than that in west China, and because of the higher reaction activity of non-methane volatile organic compounds (NMVOCs), the contributions to OH loss by NMVOCs exceed those of CO and take the dominant position in summer. The results of the sensitivity runs show a significant increase of tropospheric OH in east China from 1990 to 2000, and the trend continues. The positive effect of double emissions of NOx on OH is partly offset by the contrary effect of increased CO and CH4 emissions: the double emissions of NOx will cause an increase of OH of 18.1%-30.1%, while the increases of CO and CH4 will cause a decrease of OH of 12.2%-20.8% and 0.3%-3.0%, respectively. In turn, the lifetimes of CH4, CO, and NOx will increase by 0.3%-3.1% with regard to double emissions of CH4, 13.9%-26.3% to double emissions of CO and decrease by 15.3%-23.2% to double emissions of NOx.

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“… Matsueda et al [1999] reported observed CO over 300 ppbv between 8 and 13 km in September and October 1997 between 10°S and 30°S in the western Pacific near Australia. Chan et al [2001] reported an enhanced O 3 layer 10 km thick over Hong Kong with concentrations up to 130 ppbv.…”

Section: Introductionmentioning

confidence: 99%

Indonesian wildfires of 1997: Impact on tropospheric chemistry

et al. 2003

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[1] The Indonesian wildfires of 1997 released large amounts of trace gases and aerosols (e.g., $130 Tg of carbon monoxide (CO)) from September to November. Using the GEOS-CHEM model of tropospheric chemistry and transport, we conducted a study of this burning event, including sensitivity simulations, to estimate the impacts of the trace gas and aerosol emissions on tropospheric chemistry. The emissions from the fires were estimated using the Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI) data product and fire-count data from the Along Track Scanning Radiometer (ATSR) World Fire Atlas as surrogates for biomass burning. The model captures most of the daily variations of CO and ozone (O 3 ) observed in the region affected by the pollution. Export of the pollution from the Indonesian region was primarily in the prevailing easterlies in the free troposphere to the tropical Indian Ocean where the bulk of the pollution lay between 20°N to 20°S from September to November. The model's tropospheric CO and O 3 columns were elevated by more than 50% and 10%, respectively, over the tropical Indian Ocean in a simulation with emissions from the fires relative to a simulation without the emissions. Another important export pathway was to the tropical and subtropical South Pacific Ocean in the southern subtropical jet. A more episodic pathway occurred to the tropics and subtropics of the North Pacific Ocean. By December, the tropospheric CO column from the fires had mixed zonally and somewhat symmetrically about the equator impacting both the Northern and Southern Hemisphere similarly. The model's CO column was elevated by 10-20% from 30°N to 45°S in December, by 5-10% poleward of 45°S, and by less than 5% poleward of 45°N. The relative impact of the fires was lower in the Northern Hemisphere, as the background CO column is typically higher there. The fires decreased the concentration of the hydroxyl radical (OH) in the model by more than 20% over much of the tropical Indian Ocean through consumption by CO, heterogeneous loss of odd-oxygen radicals (HO x ) on black (BC) and organic carbon (OC) aerosols, and reduction of UV light by the aerosols. The net direct, shortwave radiative forcing at the top of the atmosphere of OC and BC aerosols from the fires was relatively small, as their forcings were similar, but of opposite signs. The net forcing at the surface, however, was large, about À10 W m À2 over most of the tropical Indian Ocean and as low as À150 W m À2 over the burning regions in Indonesia, indicating that aerosols from the fires significantly perturbed the tropical radiative budget. The calculated forcing of O 3 was minor relative to those of BC and OC aerosols.

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Effects of 1997 Indonesian forest fires on tropospheric ozone enhancement, radiative forcing, and temperature change over the Hong Kong region

Cited by 22 publications

References 33 publications

Evaluating the Effects of Radiative Forcing Feedback in Modelling Urban Ozone Air Quality in Portland, Oregon: Two-Way Coupled MM5–CMAQ Numerical Model Simulations

Evaluating the Effects of Radiative Forcing Feedback in Modelling Urban Ozone Air Quality in Portland, Oregon: Two-Way Coupled MM5–CMAQ Numerical Model Simulations

Impacts of global emissions of CO, NO x , and CH4 on China tropospheric hydroxyl free radicals

Indonesian wildfires of 1997: Impact on tropospheric chemistry

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