scholarly journals Quantitative detection of iodine in the stratosphere

2020 ◽  
Vol 117 (4) ◽  
pp. 1860-1866 ◽  
Author(s):  
Theodore K. Koenig ◽  
Sunil Baidar ◽  
Pedro Campuzano-Jost ◽  
Carlos A. Cuevas ◽  
Barbara Dix ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Anthropogenic Pollution ◽  
Oxidative Capacity ◽  
Quantitative Detection ◽  
Upper Troposphere ◽  
Quantitative Measurements ◽  
Iodine Monoxide ◽  
Oceanic Emissions ◽  
Inorganic Iodine ◽  
The Impact

Oceanic emissions of iodine destroy ozone, modify oxidative capacity, and can form new particles in the troposphere. However, the impact of iodine in the stratosphere is highly uncertain due to the lack of previous quantitative measurements. Here, we report quantitative measurements of iodine monoxide radicals and particulate iodine (Iy,part) from aircraft in the stratosphere. These measurements support that 0.77 ± 0.10 parts per trillion by volume (pptv) total inorganic iodine (Iy) is injected to the stratosphere. These high Iy amounts are indicative of active iodine recycling on ice in the upper troposphere (UT), support the upper end of recent Iy estimates (0 to 0.8 pptv) by the World Meteorological Organization, and are incompatible with zero stratospheric iodine injection. Gas-phase iodine (Iy,gas) in the UT (0.67 ± 0.09 pptv) converts to Iy,part sharply near the tropopause. In the stratosphere, IO radicals remain detectable (0.06 ± 0.03 pptv), indicating persistent Iy,part recycling back to Iy,gas as a result of active multiphase chemistry. At the observed levels, iodine is responsible for 32% of the halogen-induced ozone loss (bromine 40%, chlorine 28%), due primarily to previously unconsidered heterogeneous chemistry. Anthropogenic (pollution) ozone has increased iodine emissions since preindustrial times (ca. factor of 3 since 1950) and could be partly responsible for the continued decrease of ozone in the lower stratosphere. Increasing iodine emissions have implications for ozone radiative forcing and possibly new particle formation near the tropopause.

scholarly journals Black carbon vertical profiles strongly affect its radiative forcing uncertainty

2013 ◽  
Vol 13 (5) ◽  
pp. 2423-2434 ◽  
Author(s):  
B. H. Samset ◽  
G. Myhre ◽  
M. Schulz ◽  
Y. Balkanski ◽  
S. Bauer ◽  
...  
Keyword(s):  
Black Carbon ◽  
Vertical Profile ◽  
Radiative Forcing ◽  
Global Radiation ◽  
Radiation Balance ◽  
Upper Troposphere ◽  
Aerosol Model ◽  
Intercomparison Project ◽  
To Come ◽  
The Impact

Abstract. The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

scholarly journals Global tropospheric ozone responses to reduced NOx emissions linked to the COVID-19 worldwide lockdowns

2021 ◽  
Vol 7 (24) ◽  
pp. eabf7460
Author(s):  
Kazuyuki Miyazaki ◽  
Kevin Bowman ◽  
Takashi Sekiya ◽  
Masayuki Takigawa ◽  
Jessica L. Neu ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Oxidative Capacity ◽  
Air Pollutant ◽  
Satellite Observations ◽  
Pollutant Emissions ◽  
Ozone Production ◽  
The Impact ◽  
Data Assimilation System ◽  
Assimilation System

Efforts to stem the transmission of coronavirus disease 2019 (COVID-19) led to rapid, global ancillary reductions in air pollutant emissions. Here, we quantify the impact on tropospheric ozone using a multiconstituent chemical data assimilation system. Anthropogenic NOx emissions dropped by at least 15% globally and 18 to 25% regionally in April and May 2020, which decreased free tropospheric ozone by up to 5 parts per billion, consistent with independent satellite observations. The global total tropospheric ozone burden declined by 6TgO3 (∼2%) in May and June 2020, largely due to emission reductions in Asia and the Americas that were amplified by regionally high ozone production efficiencies (up to 4 TgO3/TgN). Our results show that COVID-19 mitigation left a global atmospheric imprint that altered atmospheric oxidative capacity and climate radiative forcing, providing a test of the efficacy of NOx emissions controls for co-benefiting air quality and climate.

scholarly journals A negative feedback between anthropogenic ozone pollution and enhanced ocean emissions of iodine

2014 ◽  
Vol 14 (15) ◽  
pp. 21917-21942 ◽  
Author(s):  
C. Prados-Roman ◽  
C. A. Cuevas ◽  
R. P. Fernandez ◽  
D. E. Kinnison ◽  
J.-F. Lamarque ◽  
...  
Keyword(s):  
Marine Environment ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Climate Model ◽  
Ozone Pollution ◽  
Iodine Compounds ◽  
Ocean Atmosphere Interaction ◽  
Atmosphere Interaction ◽  
Inorganic Iodine ◽  
The Impact

Abstract. Naturally emitted from the oceans, iodine compounds efficiently destroy atmospheric ozone and reduce its positive radiative forcing effects in the troposphere. Emissions of inorganic iodine have been experimentally shown to depend on the deposition to the oceans of tropospheric ozone, whose concentrations have significantly increased since 1850 as a result of human activities. A chemistry-climate model is used herein to quantify the current ocean emissions of inorganic iodine and assess the impact that the anthropogenic increase of tropospheric ozone has had on the natural cycle of iodine in the marine environment since pre-industrial times. Our results indicate that the human-driven enhancement of tropospheric ozone has doubled the oceanic inorganic iodine emissions following the reaction of ozone with iodide at the sea surface. The consequent build-up of atmospheric iodine, with maximum enhancements of up to 70% with respect to preindustrial times in continental pollution outflow regions, has in turn accelerated the ozone chemical loss over the oceans with strong spatial patterns. We suggest that this ocean–atmosphere interaction represents a negative geochemical feedback loop by which current ocean emissions of iodine act as a natural buffer for ozone pollution and its radiative forcing in the global marine environment.

scholarly journals The impact of recent changes in Asian anthropogenic emissions of SO<sub>2</sub> on sulfate loading in the upper troposphere and lower stratosphere and the associated radiative changes

2019 ◽  
Vol 19 (15) ◽  
pp. 9989-10008 ◽  
Author(s):  
Suvarna Fadnavis ◽  
Rolf Müller ◽  
Gayatry Kalita ◽  
Matthew Rowlinson ◽  
Alexandru Rap ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Convective Transport ◽  
The Arctic ◽  
Sulfate Aerosols ◽  
So2 Emission ◽  
Upper Troposphere ◽  
Northern India ◽  
The Impact

Abstract. Convective transport plays a key role in aerosol enhancement in the upper troposphere and lower stratosphere (UTLS) over the Asian monsoon region where low-level convective instability persists throughout the year. We use the state-of-the-art ECHAM6–HAMMOZ global chemistry–climate model to investigate the seasonal transport of anthropogenic Asian sulfate aerosols and their impact on the UTLS. Sensitivity simulations for SO2 emission perturbation over India (48 % increase) and China (70 % decrease) are performed based on the Ozone Monitoring Instrument (OMI) satellite-observed trend, rising over India by ∼4.8 % per year and decreasing over China by ∼7.0 % per year during 2006–2017. The enhanced Indian emissions result in an increase in aerosol optical depth (AOD) loading in the UTLS by 0.61 to 4.17 % over India. These aerosols are transported to the Arctic during all seasons by the lower branch of the Brewer–Dobson circulation enhancing AOD by 0.017 % to 4.8 %. Interestingly, a reduction in SO2 emission over China inhibits the transport of Indian sulfate aerosols to the Arctic in summer-monsoon and post-monsoon seasons due to subsidence over northern India. The region of sulfate aerosol enhancement shows significant warming in the UTLS over northern India, south China (0.2±0.15 to 0.8±0.72 K) and the Arctic (∼1±0.62 to 1.6±1.07 K). The estimated seasonal mean direct radiative forcing at the top of the atmosphere (TOA) induced by the increase in Indian SO2 emission is −0.2 to −1.5 W m−2 over northern India. The Chinese SO2 emission reduction leads to a positive radiative forcing of ∼0.6 to 6 W m−2 over China. The decrease in vertical velocity and the associated enhanced stability of the upper troposphere in response to increased Indian SO2 emissions will likely decrease rainfall over India.

scholarly journals Black carbon vertical profiles strongly affect its radiative forcing uncertainty

2012 ◽  
Vol 12 (11) ◽  
pp. 28929-28953 ◽  
Author(s):  
B. H. Samset ◽  
G. Myhre ◽  
M. Schulz ◽  
Y. Balkanski ◽  
S. Bauer ◽  
...  
Keyword(s):  
Black Carbon ◽  
Vertical Profile ◽  
Radiative Forcing ◽  
Global Radiation ◽  
Radiation Balance ◽  
Upper Troposphere ◽  
Aerosol Model ◽  
Intercomparison Project ◽  
To Come ◽  
The Impact

Abstract. The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

scholarly journals A negative feedback between anthropogenic ozone pollution and enhanced ocean emissions of iodine

2015 ◽  
Vol 15 (4) ◽  
pp. 2215-2224 ◽  
Author(s):  
C. Prados-Roman ◽  
C. A. Cuevas ◽  
R. P. Fernandez ◽  
D. E. Kinnison ◽  
J-F. Lamarque ◽  
...  
Keyword(s):  
Marine Environment ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Climate Model ◽  
Ozone Pollution ◽  
Iodine Compounds ◽  
Ocean Atmosphere Interaction ◽  
Atmosphere Interaction ◽  
Inorganic Iodine ◽  
The Impact

Abstract. Naturally emitted from the oceans, iodine compounds efficiently destroy atmospheric ozone and reduce its positive radiative forcing effects in the troposphere. Emissions of inorganic iodine have been experimentally shown to depend on the deposition to the oceans of tropospheric ozone, whose concentrations have significantly increased since 1850 as a result of human activities. A chemistry–climate model is used herein to quantify the current ocean emissions of inorganic iodine and assess the impact that the anthropogenic increase in tropospheric ozone has had on the natural cycle of iodine in the marine environment since pre-industrial times. Our results indicate that the human-driven enhancement of tropospheric ozone has doubled the oceanic inorganic iodine emissions following the reaction of ozone with iodide at the sea surface. The consequent build-up of atmospheric iodine, with maximum enhancements of up to 70% with respect to pre-industrial times in continental pollution outflow regions, has in turn accelerated the ozone chemical loss over the oceans with strong spatial patterns. We suggest that this ocean–atmosphere interaction represents a negative geochemical feedback loop by which current ocean emissions of iodine act as a natural buffer for ozone pollution and its radiative forcing in the global marine environment.

The Impact of Dust Storms on Aerosol Optical Depth and Radiative Forcing

2020 ◽  
Vol 16 (1) ◽  
pp. 1-14
Author(s):  
Monim Jiboori ◽  
Nadia Abed ◽  
Mohamed Abdel Wahab
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Dust Storms ◽  
The Impact

scholarly journals Anthropogenic climate change has changed frequency of past flood during 2010-2013

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yukiko Hirabayashi ◽  
Haireti Alifu ◽  
Dai Yamazaki ◽  
Yukiko Imada ◽  
Hideo Shiogama ◽  
...  
Keyword(s):  
Climate Change ◽  
South America ◽  
Radiative Forcing ◽  
Water Cycle ◽  
Flood Frequency ◽  
Anthropogenic Climate Change ◽  
Climate Change Signal ◽  
Northern Eurasia ◽  
Large Ensemble ◽  
The Impact

AbstractThe ongoing increases in anthropogenic radiative forcing have changed the global water cycle and are expected to lead to more intense precipitation extremes and associated floods. However, given the limitations of observations and model simulations, evidence of the impact of anthropogenic climate change on past extreme river discharge is scarce. Here, a large ensemble numerical simulation revealed that 64% (14 of 22 events) of floods analyzed during 2010-2013 were affected by anthropogenic climate change. Four flood events in Asia, Europe, and South America were enhanced within the 90% likelihood range. Of eight snow-induced floods analyzed, three were enhanced and four events were suppressed, indicating that the effects of climate change are more likely to be seen in the snow-induced floods. A global-scale analysis of flood frequency revealed that anthropogenic climate change enhanced the occurrence of floods during 2010-2013 in wide area of northern Eurasia, part of northwestern India, and central Africa, while suppressing the occurrence of floods in part of northeastern Eurasia, southern Africa, central to eastern North America and South America. Since the changes in the occurrence of flooding are the results of several hydrological processes, such as snow melt and changes in seasonal and extreme precipitation, and because a climate change signal is often not detectable from limited observation records, large ensemble discharge simulation provides insights into anthropogenic effects on past fluvial floods.

scholarly journals Size-resolved characterization of organic aerosol in the North China Plain: new insights from high resolution spectral analysis

2021 ◽  
Author(s):  
Weiqi Xu ◽  
Chun Chen ◽  
Yanmei Qiu ◽  
Conghui Xie ◽  
Yunle Chen ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Fine Particles ◽  
Large Fraction ◽  
Organic Aerosol ◽  
Size Distributions ◽  
The North ◽  
The Impact

Organic aerosol (OA), a large fraction of fine particles, has a large impact on climate radiative forcing and human health, and the impact depends strongly on size distributions. Here we...

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