scholarly journals Analysis of transpacific transport of black carbon during HIPPO-3: implications for black carbon aging

2014 ◽  
Vol 14 (12) ◽  
pp. 6315-6327 ◽  
Author(s):  
Z. Shen ◽  
J. Liu ◽  
L. W. Horowitz ◽  
D. K. Henze ◽  
S. Fan ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Inverse Modeling ◽  
North Pacific ◽  
Aging Process ◽  
Long Range Transport ◽  
The North ◽  
Range Transport ◽  
Transpacific Transport ◽  
The North Pacific

Abstract. Long-range transport of black carbon (BC) is a growing concern as a result of the efficiency of BC in warming the climate and its adverse impact on human health. We study transpacific transport of BC during HIPPO-3 using a combination of inverse modeling and sensitivity analysis. We use the GEOS-Chem chemical transport model and its adjoint to constrain Asian BC emissions and estimate the source of BC over the North Pacific. We find that different sources of BC dominate the transport to the North Pacific during the southbound (29 March 2010) and northbound (13 April 2010) measurements in HIPPO-3. While biomass burning in Southeast Asia (SE) contributes about 60% of BC in March, more than 90% of BC comes from fossil fuel and biofuel combustion in East Asia (EA) during the April mission. GEOS-Chem simulations generally resolve the spatial and temporal variation of BC concentrations over the North Pacific, but are unable to reproduce the low and high tails of the observed BC distribution. We find that the optimized BC emissions derived from inverse modeling fail to improve model simulations significantly. This failure indicates that uncertainties in BC removal as well as transport, rather than in emissions, account for the major biases in GEOS-Chem simulations of BC over the North Pacific. The aging process, transforming BC from hydrophobic into hydrophilic form, is one of the key factors controlling wet scavenging and remote concentrations of BC. Sensitivity tests on BC aging (ignoring uncertainties of other factors controlling BC long range transport) suggest that in order to fit HIPPO-3 observations, the aging timescale of anthropogenic BC from EA may be several hours (faster than assumed in most global models), while the aging process of biomass burning BC from SE may occur much slower, with a timescale of a few days. To evaluate the effects of BC aging and wet deposition on transpacific transport of BC, we develop an idealized model of BC transport. We find that the mid-latitude air masses sampled during HIPPO-3 may have experienced a series of precipitation events, particularly near the EA and SE source region. Transpacific transport of BC is sensitive to BC aging when the aging rate is fast; this sensitivity peaks when the aging timescale is in the range of 1–1.5 d. Our findings indicate that BC aging close to the source must be simulated accurately at a process level in order to simulate better the global abundance and climate forcing of BC.

scholarly journals Analysis of transpacific transport of black carbon during HIPPO-3: implications for black carbon aging

2014 ◽  
Vol 14 (1) ◽  
pp. 505-540 ◽  
Author(s):  
Z. Shen ◽  
J. Liu ◽  
L. W. Horowitz ◽  
D. K. Henze ◽  
S. Fan ◽  
...  
Keyword(s):  
Black Carbon ◽  
Aging Time ◽  
Biomass Burning ◽  
Inverse Modeling ◽  
North Pacific ◽  
Time Scale ◽  
Aging Process ◽  
The North ◽  
Transpacific Transport ◽  
The North Pacific

Abstract. Long-range transport of black carbon (BC) is a growing concern as a result of the efficiency of BC in warming the climate and its adverse impact on human health. We study transpacific transport of BC during HIPPO-3 using a combination of inverse modeling and sensitivity analysis. We use the GEOS-Chem chemical transport model and its adjoint to constrain Asian BC emissions and estimate the source of BC over the North Pacific. We find that different sources of BC dominate the transport to the North Pacific during the southbound (29 March 2010) and northbound (13 April 2010) measurements in HIPPO-3. While biomass burning in Southeast Asia (SE) contributes about 60% of BC in March, more than 90% of BC comes from fossil fuel and biofuel combustion in East Asia (EA) during the April mission. GEOS-Chem simulations generally resolve the spatial and temporal variation of BC concentrations over the North Pacific, but are unable to reproduce the low and high tails of the observed BC distribution. We find that the optimized BC emissions derived from inverse modeling fail to improve model simulations significantly. This failure indicates that uncertainties in BC transport, rather than in emissions, account for the major biases in GEOS-Chem simulations of BC. The aging process, transforming BC from hydrophobic into hydrophilic form, is one of the key factors controlling wet scavenging and remote concentrations of BC. Sensitivity tests on BC aging suggest that the aging time scale of anthropogenic BC from EA is several hours, faster than assumed in most global models, while the aging process of biomass burning BC from SE may occur much slower, with a time scale of a few days. To evaluate the effects of BC aging and wet deposition on transpacific transport of BC, we develop an idealized model of BC transport. We find that the mid-latitude air masses sampled during HIPPO-3 may have experienced a series of precipitation events, particularly near the EA and SE source region. Transpacific transport of BC is sensitive to BC aging when the aging rate is fast; this sensitivity peaks when the aging time scale is in the range of 1–1.5 d. Our findings indicate that BC aging close to the source must be simulated accurately at a process level in order to simulate better the global abundance and climate forcing of BC.

scholarly journals Tagged tracer simulations of black carbon in the Arctic: Transport, source contributions, and budget

2017 ◽  
Author(s):  
Kohei Ikeda ◽  
Hiroshi Tanimoto ◽  
Takafumi Sugita ◽  
Hideharu Akiyoshi ◽  
Yugo Kanaya ◽  
...  
Keyword(s):  
East Asia ◽  
Black Carbon ◽  
Long Range ◽  
Biomass Burning ◽  
East Asian ◽  
The Arctic ◽  
Long Range Transport ◽  
Middle Troposphere ◽  
Source Contributions ◽  
Range Transport

Abstract. We implemented a tagged tracer method of black carbon (BC) into a global chemistry-transport model GEOS-Chem, examined the pathways and efficiency of long-range transport from a variety of anthropogenic and biomass burning emission sources to the Arctic, and quantified the source contributions of individual emissions. Firstly, we evaluated the simulated BC by comparing it with observations at the Arctic sites and found that the simulated seasonal variations were improved by implementing an aging parameterization and reducing the wet scavenging rate by ice clouds. For tagging BC, we added BC tracers distinguished by source types (anthropogenic and biomass burning) and regions; the global domain was divided into 16 and 27 regions for anthropogenic and biomass burning emissions, respectively. Our simulations showed that BC emitted from Europe and Russia was transported to the Arctic mainly in the lower troposphere during winter and spring. In particular, BC transported from Russia was widely spread over the Arctic in winter and spring, leading to a dominant contribution of 62 % to the Arctic BC near the surface as the annual mean. In contrast, BC emitted from East Asia was found to be transported in the middle troposphere into the Arctic mainly over the Okhotsk Sea and East Siberia during winter and spring. We identified an important window area, which allowed a strong incoming of East Asian BC to the Arctic (130°–180° E and 3–8 km altitude at 66° N). The model demonstrated that the contribution from East Asia to the Arctic had a maximum at about 5 km altitude due to uplifting during the long-range transport in early spring. The efficiency of BC transport from East Asia to the Arctic was smaller than that from other large source regions such as Europe, Russia and North America. However, the East Asian contribution was most important for BC in the middle troposphere (41 %) and BC burden over the Arctic (27 %) because of the large emissions from this region. These results suggested that the main sources of the Arctic BC differed with altitude. The contribution of all the anthropogenic sources to Arctic BC concentrations near the surface was dominant (90 %) on an annual basis. The contributions of biomass burning in boreal regions (Siberia, Alaska and Canada) to the annual total BC deposition onto the Arctic were estimated to be 12–15 %, which became the maximum during summer.

scholarly journals Source apportionment and impact of long-range transport on carbonaceous aerosol particles in central Germany during HCCT-2010

2021 ◽  
Vol 21 (5) ◽  
pp. 3667-3684
Author(s):  
Laurent Poulain ◽  
Benjamin Fahlbusch ◽  
Gerald Spindler ◽  
Konrad Müller ◽  
Dominik van Pinxteren ◽  
...  
Keyword(s):  
Black Carbon ◽  
Long Range ◽  
Biomass Burning ◽  
Mass Concentration ◽  
Carbonaceous Aerosol ◽  
Long Range Transport ◽  
Air Masses ◽  
Central Germany ◽  
Range Transport ◽  
Local Emissions

Abstract. The identification of different sources of the carbonaceous aerosol (organics and black carbon) was investigated at a mountain forest site located in central Germany from September to October 2010 to characterize incoming air masses during the Hill Cap Cloud Thuringia 2010 (HCCT-2010) experiment. The near-PM1 chemical composition, as measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), was dominated by organic aerosol (OA; 41 %) followed by sulfate (19 %) and nitrate (18 %). Source apportionment of the OA fraction was performed using the multilinear engine (ME-2) approach, resulting in the identification of the following five factors: hydrocarbon-like OA (HOA; 3 % of OA mass), biomass burning OA (BBOA; 13 %), semi-volatile-like OA (SV-OOA; 19 %), and two oxygenated OA (OOA) factors. The more oxidized OOA (MO-OOA, 28 %) was interpreted as being influenced by aged, polluted continental air masses, whereas the less oxidized OOA (LO-OOA, 37 %) was found to be more linked to aged biogenic sources. Equivalent black carbon (eBC), measured by a multi-angle absorption photometer (MAAP) represented 10 % of the total particulate matter (PM). The eBC was clearly associated with HOA, BBOA, and MO-OOA factors (all together R2=0.83). Therefore, eBC's contribution to each factor was achieved using a multi-linear regression model. More than half of the eBC (52 %) was associated with long-range transport (i.e., MO-OOA), whereas liquid fuel eBC (35 %) and biomass burning eBC (13 %) were associated with local emissions, leading to a complete apportionment of the carbonaceous aerosol. The separation between local and transported eBC was well supported by the mass size distribution of elemental carbon (EC) from Berner impactor samples. Air masses with the strongest marine influence, based on back trajectory analysis, corresponded with a low particle mass concentration (6.4–7.5 µg m−3) and organic fraction (≈30 %). However, they also had the largest contribution of primary OA (HOA ≈ 4 % and BBOA 15 %–20 %), which was associated with local emissions. Continental air masses had the highest mass concentration (11.4–12.6 µg m−3), and a larger fraction of oxygenated OA (≈45 %) indicated highly processed OA. The present results emphasize the key role played by long-range transport processes not only in the OA fraction but also in the eBC mass concentration and the importance of improving our knowledge on the identification of eBC sources.

scholarly journals Source apportionment and impact of long-range transport on carbonaceous aerosol particles in Central Germany during HCCT-2010

2020 ◽  
Author(s):  
Laurent Poulain ◽  
Benjamin Fahlbusch ◽  
Gerald Spindler ◽  
Konrad Müller ◽  
Dominik van Pinxteren ◽  
...  
Keyword(s):  
Black Carbon ◽  
Long Range ◽  
Biomass Burning ◽  
Mass Concentration ◽  
Carbonaceous Aerosol ◽  
Long Range Transport ◽  
Air Masses ◽  
Central Germany ◽  
Range Transport ◽  
Local Emissions

Abstract. The identification of different sources of the carbonaceous aerosol (organics and black carbon) was investigated at a mountain forest site located in central Germany from September to October 2010 to characterize incoming air masses during the Hill Cap Cloud Thuringia 2010 (HCCT-2010) experiment. The near-PM1 chemical composition, as measured by an Aerosol Mass Spectrometer (HR-ToF-AMS), was dominated by organics (OA, 41 %), followed by sulfate (19 %) and nitrate (18 %). Source apportionment of the OA fraction was performed using the Multilinear Engine approach (ME-2), resulting in the identification of five factors: Hydrocarbon-like OA (HOA, 3 % of OA mass), biomass burning OA (BBOA, 13 %), semi-volatile-like OA (SVOOA, 19 %), and two oxygenated OA (OOA) factors. The more-oxidized OOA (MO-OOA, 28 %) was interpreted as being influenced by aged polluted continental air masses, whereas the less-oxidized OOA (LO-OOA, 37 %) was found to be more linked to aged biogenic sources. Equivalent black carbon (eBC) measured by a multi-angle absorption photometer, MAAP, represented 10 % of the total PM. The eBC was clearly associated with the three factors HOA, BBOA, and MO-OOA (all together R2 = 0.83). Therefore, eBC's contribution to each factor was achieved using a multi-linear regression model. More than half of the eBC (52 %) was associated with long-range transport (i.e. MO-OOA), whereas liquid fuel eBC (35 %) and biomass burning eBC (13 %) were associated with local emissions leading to a complete apportionment of the carbonaceous aerosol. The separation between local and transported eBC was well supported by the mass size distribution of elemental carbon (EC) from Berner-impactor samples. Air masses with the strongest marine influence based on back trajectory analysis corresponded with a low particle mass concentration (6.4–7.5 µg m−3) and organic fraction (≈ 30 %). However, they also had the largest contribution of primary OA (HOA ≈ 4 % and BBOA 15–20 %), which was associated with local emissions. Continental air masses had the highest mass concentration (11.4–12.6 µg m−3) and a larger fraction of oxygenated OA (≈ 45 %) indicated highly processed OA. The present results emphasize the key role played by long-range transport processes not only on the OA fraction but also on the eBC mass concentration and the importance of improving our knowledge on the identification of eBC sources.

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