Removal of NOxand NOyin biomass burning plumes in the boundary layer over northern Australia

2003 ◽  
Vol 108 (D10) ◽  
Author(s):  
N. Takegawa
Keyword(s):  
Boundary Layer ◽  
Biomass Burning ◽  
Northern Australia

Photochemical production of O3in biomass burning plumes in the boundary layer over northern Australia

2003 ◽  
Vol 30 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. Takegawa ◽  
Y. Kondo ◽  
M. Ko ◽  
M. Koike ◽  
K. Kita ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Biomass Burning ◽  
Northern Australia ◽  
Photochemical Production

scholarly journals Investigation of NO<sub>2</sub> vertical distribution using two DOAS retrievals for GOME-2A measurements in the UV and vis spectral range

2017 ◽  
Author(s):  
Lisa K. Behrens ◽  
Andreas Hilboll ◽  
Andreas Richter ◽  
Enno Peters ◽  
Henk Eskes ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Radiative Transfer ◽  
Vertical Distribution ◽  
Spectral Range ◽  
Biomass Burning ◽  
Vertical Profile ◽  
Lower Troposphere ◽  
Tropical Africa ◽  
Profile Shape ◽  
Spectral Ranges

Abstract. In this study, we present a novel NO2 DOAS retrieval in the ultraviolet (UV) spectral range for satellite observations from the Global Ozone Monitoring Instrument 2 on board EUMETSAT’s MetOp-A (GOME-2A) satellite. We compare the results to those from an established NO2 retrieval in the visible (vis) spectral range from the same instrument and infer information about the NO2 vertical profile shape in the troposphere. As expected, radiative transfer calculations for satellite geometries show that the sensitivity close to the ground is higher in the vis than in the UV spectral range. Consequently, NO2 slant column densities (SCDs) in the vis are usually higher than in the UV, if the NO2 is close to the surface. Therefore, these differences in NO2 SCDs between the two spectral ranges contain information on the vertical distribution of NO2 in the troposphere. We combine these results with radiative transfer calculations and simulated NO2 fields from the TM5 chemistry transport model to evaluate the simulated NO2 vertical distribution. We investigate regions representative for both anthropogenic and biomass burning NO2 pollution. Anthropogenic air pollution is mostly located in the boundary layer close to the surface, which is reflected by the large differences between UV and vis SCDs of ~ 60 %. Biomass burning NO2 in contrast is often uplifted into elevated layers above the boundary layer. This is best seen in tropical Africa south of the equator, where the biomass burning NO2 is well observed in the UV, and the difference between the two spectral ranges is only ~ 36 %. In tropical Africa north of the equator, however, the biomass burning NO2 is located closer to the ground, reducing its visibility. While not enabling a full retrieval of the vertical NO2 profile shape in the troposphere, our results can help to constrain the vertical profile of NO2 in the lower troposphere and, when analyzed together with simulated NO2 fields, can help interpret the model output.

scholarly journals GOME-2A retrievals of tropospheric NO<sub>2</sub> in different spectral ranges – influence of penetration depth

2018 ◽  
Vol 11 (5) ◽  
pp. 2769-2795 ◽  
Author(s):  
Lisa K. Behrens ◽  
Andreas Hilboll ◽  
Andreas Richter ◽  
Enno Peters ◽  
Henk Eskes ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Radiative Transfer ◽  
Spectral Range ◽  
Biomass Burning ◽  
Vertical Profile ◽  
Lower Troposphere ◽  
Optical Absorption Spectroscopy ◽  
Tropical Africa ◽  
Profile Shape ◽  
Spectral Ranges

Abstract. In this study, we present a novel nitrogen dioxide (NO2) differential optical absorption spectroscopy (DOAS) retrieval in the ultraviolet (UV) spectral range for observations from the Global Ozone Monitoring Instrument 2 on board EUMETSAT's MetOp-A (GOME-2A) satellite. We compare the results to those from an established NO2 retrieval in the visible (vis) spectral range from the same instrument and investigate how differences between the two are linked to the NO2 vertical profile shape in the troposphere.As expected, radiative transfer calculations for satellite geometries show that the sensitivity close to the ground is higher in the vis than in the UV spectral range. Consequently, NO2 slant column densities (SCDs) in the vis are usually higher than in the UV if the NO2 is close to the surface. Therefore, these differences in NO2 SCDs between the two spectral ranges contain information on the vertical distribution of NO2 in the troposphere. We combine these results with radiative transfer calculations and simulated NO2 fields from the TM5-MP chemistry transport model to evaluate the simulated NO2 vertical distribution.We investigate regions representative of both anthropogenic and biomass burning NO2 pollution. Anthropogenic air pollution is mostly located in the boundary layer close to the surface, which is reflected by large differences between UV and vis SCDs of  ∼  60 %. Biomass burning NO2 in contrast is often uplifted into elevated layers above the boundary layer. This is best seen in tropical Africa south of the Equator, where the biomass burning NO2 is well observed in the UV, and the SCD difference between the two spectral ranges is only  ∼  36 %. In tropical Africa north of the Equator, however, the biomass burning NO2 is located closer to the ground, reducing its visibility in the UV.While not enabling a full retrieval of the vertical NO2 profile shape in the troposphere, our results can help to constrain the vertical profile of NO2 in the lower troposphere and, when analysed together with simulated NO2 fields, can help to better interpret the model output.

scholarly journals Optical and physical properties of aerosols in the boundary layer and free troposphere over the Amazon Basin during the biomass burning season

2006 ◽  
Vol 6 (10) ◽  
pp. 2911-2925 ◽  
Author(s):  
D. Chand ◽  
P. Guyon ◽  
P. Artaxo ◽  
O. Schmid ◽  
G. P. Frank ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Light Scattering ◽  
Physical Properties ◽  
Biomass Burning ◽  
Large Scale ◽  
Amazon Basin ◽  
Single Scattering ◽  
Free Troposphere ◽  
Wet Season ◽  
Average Mass

Abstract. As part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall and Climate (LBA-SMOCC) campaign, detailed surface and airborne aerosol measurements were performed over the Amazon Basin during the dry to wet season from 16 September to 14 November 2002. Optical and physical properties of aerosols at the surface, and in the boundary layer (BL) and free troposphere (FT) during the dry season are discussed in this article. Carbon monoxide (CO) is used as a tracer for biomass burning emissions. At the surface, good correlation among the light scattering coefficient (σs at 545 nm), PM2.5, and CO indicates that biomass burning is the main source of aerosols. Accumulation of haze during some of the large-scale biomass burning events led to high PM2.5 (225 μg m−3), σs (1435 Mm−1), aerosol optical depth at 500 nm (3.0), and CO (3000 ppb). A few rainy episodes reduced the PM2.5, number concentration (CN) and CO concentration by two orders of magnitude. The correlation analysis between σs and aerosol optical thickness shows that most of the optically active aerosols are confined to a layer with a scale height of 1617 m during the burning season. This is confirmed by aircraft profiles. The average mass scattering and absorption efficiencies (545 nm) for small particles (diameter Dp<1.5 μm) at surface level are found to be 5.0 and 0.33 m2 g−1, respectively, when relating the aerosol optical properties to PM2.5 aerosols. The observed mean single scattering albedo (ωo at 545 nm) for submicron aerosols at the surface is 0.92±0.02. The light scattering by particles (Δσs/Δ CN) increase 2–10 times from the surface to the FT, most probably due to the combined affects of coagulation and condensation.

Black Carbon profiles from tethered balloon flights over the Southeastern Tibetan Plateau

2020 ◽  
Author(s):  
Mo Wang ◽  
Baiqing Xu ◽  
Song Yang ◽  
Jing Gao ◽  
Taihua Zhang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Relative Humidity ◽  
Tibetan Plateau ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Vertical Profile ◽  
Mass Concentration ◽  
Maximum Height ◽  
Free Troposphere ◽  
Tethered Balloon

&lt;p&gt;Black carbon (BC) can change the energy budget of the earth system by strongly absorbing solar radiation: both suspended in the atmosphere, incorporated into cloud droplets, or deposited onto high-albedo surfaces. BC&amp;#8217;s direct radiative forcing is highly dependent on its vertical distribution. However, due to large variabilities and the small number of vertical profile measurements, there is still large uncertainty in this forcing value. Moreover, the vertical profile of BC and its relative elevation to clouds determine BC&amp;#8217;s lifetime in the atmosphere and its transport and removal processes. In November-December 2017, a series of tethered balloon flights was launched at the Southeast Tibet Observation and Research Station for the Alpine Environment of the Chinese Academy of Sciences. A cylindrical balloon with a diameter of 7.9 m and maximum volume of 1250 m&lt;sup&gt;3&lt;/sup&gt; was used. A 7-channel Aethalometer was installed in the gondola attached to the balloon, together with several other instruments including a GPS for altitude, and sensors for temperature and relative humidity. The airborne Aethalometer measured BC mass concentration (ng/m&lt;sup&gt;3&lt;/sup&gt;) on a on a 1-second timebase at 7 wavelengths ranging from 370 nm to 950 nm. Meanwhile, another Aethalometer was used to monitor BC mass concentration near the surface, at a height of about 10 m above the ground. From the tethered balloon flights, we derived three profiles designated as &amp;#8216;F1&amp;#8217;, &amp;#8216;F3-ASC&amp;#8217;, and &amp;#8216;F3-DES&amp;#8217;. The maximum height for the F1 flight was 500 m a.g.l., namely 3800 m a.s.l.; while the maximum height for the F3 flight was 1950 m a.g.l., namely 5250 m a.s.l. Based on the potential temperature and relative humidity data, the profiles were divided into three layers: the stable boundary layer (SBL), the residual layer (RL), and the free troposphere (FT). The vertical distribution of BC shows a prominent peak within the SBL. The mean BC concentration in SBL (1000&amp;#177;750 ng/m&lt;sup&gt;3&lt;/sup&gt;) was one order of magnitude higher than in RL and FT, which were 140&amp;#177;40 ng/m&lt;sup&gt;3&lt;/sup&gt; and 120&amp;#177;40 ng/m&lt;sup&gt;3&lt;/sup&gt;, respectively. The BC concentration measured in the present study in FT over the southeastern Tibetan Plateau is comparable to measurements in Arctic regions, but lower than values in South Asia. Analysis of the wavelength dependence of the data yields an estimate of the biomass burning contribution. This showed a maximum value in SBL of 44&amp;#177;37%, and was 16&amp;#177;6% in RL and 13&amp;#177;5% in FT. Analysis of 24-hour isentropic back trajectories showed that BC in SBL and RL was dominated by local sources, while in the FT, BC is mainly influenced by mid- to long-distant transport by the westerlies. In addition, analysis of the variations of BC concentration and biomass burning contribution on a high-resolution time scale showed that BC concentrations and the nature of their sources are largely influenced by air mass origins and transport. To our knowledge, this is the first ever in situ measurement of BC concentration over the Tibetan Plateau in the atmospheric boundary layer and free troposphere up to 5000 m a.s.l.&lt;/p&gt;

scholarly journals Numerical simulation of tropospheric injection of biomass burning products by pyro-thermal plumes

2010 ◽  
Vol 10 (8) ◽  
pp. 3463-3478 ◽  
Author(s):  
C. Rio ◽  
F. Hourdin ◽  
A. Chédin
Keyword(s):  
Boundary Layer ◽  
Biomass Burning ◽  
General Circulation ◽  
Circulation Model ◽  
Thermal Plume ◽  
Near Surface ◽  
Fire Emissions ◽  
Boundary Layer Height ◽  
Convective Structures ◽  
Environmental Air

Abstract. The thermal plume model, a mass-flux scheme originally developed to represent the vertical transport by convective structures within the boundary layer, is adapted to the representation of plumes generated by fires, with the aim of estimating the height at which fire emissions are actually injected in the atmosphere. The parameterization, which takes into account the excess of near surface temperature induced by fires and the mixing between convective plumes and environmental air, is first evaluated on two well-documented fires. Simulations over Southern Africa performed with the general circulation model LMDZ over one month show that the CO2 can be injected far above the boundary layer height, leading to a daily excess of CO2 in the mid-troposphere of an order of 2 ppmv. These results agree with satellite retrievals of a diurnal cycle of CO2 in the free troposphere over regions affected by biomass burning in the Tropics.

scholarly journals Optical and physical properties of aerosols in the boundary layer and free troposphere over the Amazon Basin during the biomass burning season

2005 ◽  
Vol 5 (4) ◽  
pp. 4373-4406 ◽  
Author(s):  
D. Chand ◽  
P. Guyon ◽  
P. Artaxo ◽  
O. Schmid ◽  
G. P. Frank ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Physical Properties ◽  
Biomass Burning ◽  
Large Scale ◽  
Amazon Basin ◽  
High Mass ◽  
Surface Boundary ◽  
Free Troposphere ◽  
Wet Season ◽  
Average Mass

Abstract. As part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall and Climate (LBA-SMOCC) campaign, detailed surface and airborne aerosol measurements were performed over the Amazon Basin during the dry to wet season from 16 September to 14 November 2002. Optical and physical properties of aerosols at the surface, boundary layer (BL) and free troposphere (FT) during the dry season are discussed in this article. Carbon monoxide (CO) is used as a tracer for biomass burning emissions. At the surface, good correlation among the light scattering coefficient (σs at 550 nm), PM2.5, and CO indicates that biomass burning is the main source of aerosols. Accumulation of haze during some of the large-scale biomass burning events led to high mass loadings (PM2.5=200 µgm−3), σs (1400 Mm−1), aerosol optical depth at 500 nm (3.0), and CO (3000 ppb). A few rainy episodes reduced the aerosol mass loading, number concentration (CN) and CO concentration by two orders of magnitude. The correlation analysis between σs and aerosol optical thickness shows that most of the optically active aerosols are confined to a layer with a scale height of 1660 m during the burning season. The average mass scattering and absorption efficiencies (532 nm) for small particles (diameter Dp<1.5 µm) at surface level are found to be 5.3 and 0.42 m2 g−1, respectively, when relating the aerosol optical properties to PM2.5 aerosols. The observed mean single scattering albedo (ωo at ~540 nm) for submicron aerosols at the surface (0.92±0.02) is significantly higher than reported previously. The scattering efficiency (dσs/dCN) of particles increases 2–10 times from the surface to the FT, most probably due to the combined affects of coagulation and condensation.

scholarly journals Aircraft observations of enhancement and depletion of black carbon mass in the springtime Arctic

2010 ◽  
Vol 10 (6) ◽  
pp. 15167-15196
Author(s):  
J. R. Spackman ◽  
R. S. Gao ◽  
W. D. Neff ◽  
J. P. Schwarz ◽  
L. A. Watts ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Black Carbon ◽  
Biomass Burning ◽  
Boundary Layer Transition ◽  
Arctic Climate ◽  
The Arctic ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Air Mass ◽  
The Impact

Abstract. Understanding the processes controlling black carbon (BC) in the Arctic is crucial for evaluating the impact of anthropogenic and natural sources of BC on Arctic climate. Vertical profiles of BC mass were observed from the surface to near 7-km altitude in April 2008 using a Single-Particle Soot Photometer (SP2) during flights on the NOAA WP-3D research aircraft from Fairbanks, Alaska. These measurements were conducted during the NOAA-sponsored Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project as part of POLARCAT, an International Polar Year (IPY) activity. In the free troposphere, the Arctic air mass was influenced by long-range transport from biomass-burning and anthropogenic source regions at lower latitudes especially during the latter part of the campaign. Maximum average BC mass loadings of 150 ng kg−1 were observed near 5.5-km altitude in the aged Arctic air mass. In biomass-burning plumes, BC was enhanced from near the top of the Arctic boundary layer (ABL) to 5.5 km compared to the aged Arctic air mass. At the bottom of some of the profiles, positive vertical gradients in BC were observed in the vicinity of open leads in the sea-ice. BC mass loadings increased by about a factor of two across the boundary layer transition in the ABL in these cases while carbon monoxide (CO) remained constant, evidence for depletion of BC in the ABL. BC mass loadings were positively correlated with O3 in ozone depletion events (ODEs) for all the observations in the ABL suggesting that BC was removed by dry deposition of BC on the snow or ice because molecular bromine, Br2, which photolyzes and catalytically destroys O3, is thought to be released near the open leads in regions of ice formation. We estimate the deposition flux of BC mass to the snow using a box model constrained by the vertical profiles of BC in the ABL. The open leads may increase vertical mixing in the ABL and entrainment of pollution from the free troposphere possibly enhancing the deposition of BC to the snow.

scholarly journals Long-term multi-source data analysis about the characteristics of aerosol optical properties and types over Australia

2021 ◽  
Vol 21 (5) ◽  
pp. 3803-3825
Author(s):  
Xingchuan Yang ◽  
Chuanfeng Zhao ◽  
Yikun Yang ◽  
Hao Fan
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Seasonal Variations ◽  
Northern Australia ◽  
Aerosol Optical Properties ◽  
Austral Spring ◽  
Australian Continent ◽  
Modis Aod ◽  
Central Australia ◽  
Aerosol Types

Abstract. The spatiotemporal distributions of aerosol optical properties and major aerosol types, along with the vertical distribution of major aerosol types over Australia, are investigated based on multi-year Aerosol Robotic Network (AERONET) observations at nine sites, the Moderate Resolution Imaging Spectroradiometer (MODIS), Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and back-trajectory analysis from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT). During the observation period from 2001–2020, the annual aerosol optical depth (AOD) at most sites showed increasing trends (0.002–0.029 yr−1), except for that at three sites, Canberra, Jabiru, and Lake Argyle, which showed decreasing trends (−0.004 to −0.014 yr−1). In contrast, the annual Ångström exponent (AE) showed decreasing tendencies at most sites (−0.045 to −0.005 yr−1). The results showed strong seasonal variations in AOD, with high values in the austral spring and summer and relatively low values in the austral fall and winter, and weak seasonal variations in AE, with the highest mean values in the austral spring at most sites. Monthly average AOD increases from August to December or the following January and decreases during March–July. Spatially, the MODIS AOD showed obvious spatial heterogeneity, with high values appearing over the Australian tropical savanna regions, Lake Eyre Basin, and southeastern regions of Australia, while low values appeared over the arid regions in western Australia. MERRA-2 showed that carbonaceous aerosol over northern Australia, dust over central Australia, sulfate over densely populated northwestern and southeastern Australia, and sea salt over Australian coastal regions are the major types of atmospheric aerosols. The nine ground-based AERONET sites over Australia showed that the mixed type of aerosols (biomass burning and dust) is dominant in all seasons. Moreover, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) showed that polluted dust is the dominant aerosol type detected at heights 0.5–5 km over the Australian continent during all seasons. The results suggested that Australian aerosol has similar source characteristics due to the regional transport over Australia, especially for biomass burning and dust aerosols. However, the dust-prone characteristic of aerosol is more prominent over central Australia, while the biomass-burning-prone characteristic of aerosol is more prominent in northern Australia.

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