scholarly journals The Saharan Aerosol Long-Range Transport and Aerosol–Cloud-Interaction Experiment: Overview and Selected Highlights

2017 ◽  
Vol 98 (7) ◽  
pp. 1427-1451 ◽  
Author(s):  
Bernadett Weinzierl ◽  
A. Ansmann ◽  
J. M. Prospero ◽  
D. Althausen ◽  
N. Benker ◽  
...  
Keyword(s):  
Long Range ◽  
The United States ◽  
Radiation Budget ◽  
Long Range Transport ◽  
Airborne Measurements ◽  
Aerosol Cloud ◽  
Range Transport ◽  
Interaction Experiment ◽  
The Caribbean ◽  
The Impact

Abstract North Africa is the world’s largest source of dust, a large part of which is transported across the Atlantic to the Caribbean and beyond where it can impact radiation and clouds. Many aspects of this transport and its climate effects remain speculative. The Saharan Aerosol Long-Range Transport and Aerosol–Cloud-Interaction Experiment (SALTRACE; www.pa.op.dlr.de/saltrace) linked ground-based and airborne measurements with remote sensing and modeling techniques to address these issues in a program that took place in 2013/14. Specific objectives were to 1) characterize the chemical, microphysical, and optical properties of dust in the Caribbean, 2) quantify the impact of physical and chemical changes (“aging”) on the radiation budget and cloud microphysical processes, 3) investigate the meteorological context of transatlantic dust transport, and 4) assess the roles of removal processes during transport. SALTRACE was a German-led initiative involving scientists from Europe, Cabo Verde, the Caribbean, and the United States. The Falcon research aircraft of the Deutsches Zentrum für Luft- und Raumfahrt (DLR), equipped with a comprehensive aerosol and wind lidar payload, played a central role. Several major dust outbreaks were studied with 86 h of flight time under different conditions, making it by far the most extensive investigation on long-range transported dust ever made. This article presents an overview of SALTRACE and highlights selected results including data from transatlantic flights in coherent air masses separated by more than 4,000-km distance that enabled measurements of transport effects on dust properties. SALTRACE will improve our knowledge on the role of mineral dust in the climate system and provide data for studies on dust interactions with clouds, radiation, and health.

scholarly journals Long-range Transport Impacts on Surface Aerosol Concentrations and the Contributions to Haze Events in China: an HTAP2 Multi-Model Study

2018 ◽  
Author(s):  
Xinyi Dong ◽  
Joshua S. Fu ◽  
Qingzhao Zhu ◽  
Jian Sun ◽  
Jiani Tan ◽  
...  
Keyword(s):  
East Asia ◽  
Long Range ◽  
Source Region ◽  
Long Range Transport ◽  
Special Focus ◽  
Anthropogenic Emission ◽  
Multiple Model ◽  
Aerosol Mass Concentration ◽  
Range Transport ◽  
The Impact

Abstract. Haze has been severely affecting the densely populated areas in China during recent years. While many of the pilot studies have been devoted to investigate the contributions from local anthropogenic emission, limited attention has been paid to the influence from long-range transport. In this study, we use simulations from 6 participating models supplied through the Task Force on Hemispheric Transport of Air Pollution Phase 2 (HTAP2) exercise to investigate the long-range transport impact of Europe and Russia/Belarussia/Ukraine on the surface air quality in East Asia, with special focus on their contributions during the haze episodes over China. The impact of 20 % anthropogenic emission perturbation from the source region is extrapolated by a factor of 5 to estimate the full impact. We find that the full impacts from EUR and RBU are 0.99 µg/m3 (3.1 %) and 1.32 µg/m3 (4.1 %) respectively during haze episodes, while the annual averaged full impacts are only 0.35 µg m3 (1.7 %) and 0.53 µg/m3 (2.6 %) respectively. By estimating the aerosol response within and above the planetary boundary layer (PBL), we find that long-range transport within the PBL contributes to 22–38 % of the total column density of aerosol response. Comparison with the HTAP Phase 1 (HTAP1) assessment reveals that from 2000 to 2010, the long-range transport from Europe to East Asia has decreased significantly by a factor of 2–10 for surface aerosol mass concentration due to the simultaneous emission reduction in source region and emission increase in the receptor region. By investigating the visibility response, we find that the long-range transport from the Europe and RBU region increases the number of haze events in China by 0.15 % and 0.11 % respectively, and the North China Plain and southeast China receives 1–3 extra haze days. This study is the first investigation into the contribution of long-range transport to haze in China with multiple model experiments.

scholarly journals Long-Range Transport Influence on Key Chemical Components of PM2.5 in the Seoul Metropolitan Area, South Korea, during the Years 2012–2016

Atmosphere ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 48 ◽  
Author(s):  
Changhan Bae ◽  
Byeong-Uk Kim ◽  
Hyun Cheol Kim ◽  
Chul Yoo ◽  
Soontae Kim
Keyword(s):  
Long Range ◽  
Metropolitan Area ◽  
Inorganic Ions ◽  
Long Range Transport ◽  
Chemical Components ◽  
Component Ratio ◽  
Seoul Metropolitan Area ◽  
Range Transport ◽  
The Impact ◽  
Pm2.5 Concentration

This study identified the key chemical components based on an analysis of the seasonal variations of ground level PM2.5 concentrations and its major chemical constituents (sulfate, nitrate, ammonium, organic carbon, and elemental carbon) in the Seoul Metropolitan Area (SMA), over a period of five years, ranging from 2012 to 2016. It was found that the mean PM2.5 concentration in the SMA was 33.7 μg/m3, while inorganic ions accounted for 53% of the total mass concentration. The component ratio of inorganic ions increased by up to 61%–63% as the daily mean PM2.5 concentration increased. In spring, nitrate was the dominant component of PM2.5, accounting for 17%–32% of the monthly mean PM2.5 concentrations. In order to quantify the impact of long-range transport on the SMA PM2.5, a set of sensitivity simulations with the community multiscale air-quality model was performed. Results show that the annual averaged impact of Chinese emissions on SMA PM2.5 concentrations ranged from 41% to 44% during the five years. Chinese emissions’ impact on SMA nitrate ranged from 50% (winter) to 67% (spring). This result exhibits that reductions in SO2 and NOX emissions are crucial to alleviate the PM2.5 concentration. It is expected that NOX emission reduction efforts in China will help decrease PM2.5 concentrations in the SMA.

scholarly journals Global impact of road traffic emissions on tropospheric ozone

2007 ◽  
Vol 7 (7) ◽  
pp. 1707-1718 ◽  
Author(s):  
S. Matthes ◽  
V. Grewe ◽  
R. Sausen ◽  
G.-J. Roelofs
Keyword(s):  
Long Range ◽  
Road Traffic ◽  
Road Transport ◽  
Traffic Emissions ◽  
Long Range Transport ◽  
Global Impact ◽  
Road Traffic Emissions ◽  
Ozone Distribution ◽  
Range Transport ◽  
The Impact

Abstract. Road traffic is one of the major anthropogenic emission sectors for NOx, CO and NMHCs (non-methane hydrocarbons). We applied ECHAM4/CBM, a general circulation model coupled to a chemistry module, which includes higher hydrocarbons, to investigate the global impact of 1990 road traffic emissions on the atmosphere. Improving over previous global modelling studies, which concentrated on road traffic NOx and CO emissions only, we assess the impact of NMHC emissions from road traffic. It is revealed that NMHC emissions from road traffic play a key role for the impact on ozone. They are responsible for (indirect) long-range transport of NOx from road traffic via the formation of PAN, which is not found in a simulation without NMHC emissions from road traffic. Long-range transport of NMHC-induced PAN impacts on the ozone distribution in Northern Hemisphere regions far away from the sources, especially in arctic and remote maritime regions. In July total road traffic emissions (NOx, CO and NMHCs) contribute to the zonally averaged ozone distribution by more than 12% near the surface in the Northern Hemisphere midlatitudes and arctic latitudes. In January road traffic emissions contribute near the surface in northern and southern extratropics more than 8%. Sensitivity studies for regional emission show that effective transport of road traffic emissions occurs mainly in the free troposphere. In tropical latitudes of America up to an altitude of 200 hPa, global road traffic emissions contribute about 8% to the ozone concentration. In arctic latitudes NMHC emissions from road transport are responsible for about 90% of PAN increase from road transport, leading to a contribution to ozone concentrations of up to 15%.

scholarly journals Retrieval of microphysical dust particle properties from SALTRACE lidar observations: Case studies

2020 ◽  
Author(s):  
Stefanos Samaras ◽  
Christine Böckmann ◽  
Moritz Haarig ◽  
Albert Ansmann ◽  
Adrian Walser ◽  
...  
Keyword(s):  
Long Range ◽  
Software Tool ◽  
Total Surface Area ◽  
Saharan Dust ◽  
Radiation Budget ◽  
Dust Particles ◽  
Long Range Transport ◽  
Raman Lidar ◽  
Microphysical Properties ◽  
Range Transport

Abstract. Saharan dust is a major natural atmospheric aerosol component with significant impact on the Earth radiation budget. In this work we determine the microphysical properties of dust particles after a long-range transport over the Atlantic Ocean, using input from three depolarization channels of a multi-wavelength polarization Raman lidar. The measurements were performed at Barbados in the framework of the Saharan Aerosol Long-Range Transport and Aerosol–Cloud-Interaction Experiment (SALTRACE) in the summers of 2013 and 2014. The microphysical retrievals are performed with the software tool SphInX (Spheroidal Inversion Experiments) which uses regularization for the inversion process and a new two-dimensional (2-D) extension of the Mie model approximating dust with spheroids. The method allows us to simultaneously retrieve shape- and size-dependent particle distributions. Because dust particles are mostly non-spherical this software tool fills the gap in estimating the non-spherical particle fraction. Two cases measured on 10 July 2013 and 20 June 2014 are discussed. 2-D radius-bimodal shape-size distribution are retrieved. The ratio of spherical-to-non-spherical contributions to the particle number concentration was found to be about 3/7. A volume-weighted effective aspect ratio of 1.1 was obtained, indicating slightly prolate particles. The total effective radius for the two cases in the preselected radius range from 0.01–2.2 μm was found to be, on average, 0.75 μm. The stronger dust event (10 July 2013) showed about 24 % higher values for the total surface-area and volume concentration. Finally, we compare our results with the ones from the polarization lidar-photometer networking (POLIPHON) method and ground-based photometers as well as with airborne in situ particle counters. Considering all differences in these independent approaches, we find a qualitatively good agreement between the different results and a consistent description of the dust cases. Such an extensive comparison is a novel and fruitful exercise and corroborates that the mathematical retrieval based on Raman lidar data of particle backscattering, extinction, and depolarization is a powerful tool even in the case of dust particles.

scholarly journals IASI nitrous oxide (N<sub>2</sub>O) retrievals: validation and application to transport studies at daily time scales

2018 ◽  
Author(s):  
Yannick Kangah ◽  
Philippe Ricaud ◽  
Jean-Luc Attié ◽  
Naoko Saitoh ◽  
Jérôme Vidot ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Long Range ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Daily Basis ◽  
Environmental Research ◽  
Long Range Transport ◽  
Absorption Bands ◽  
Range Transport ◽  
The Impact

Abstract. The aim of this paper is to present a method to retrieve nitrous oxide (N2O) vertical profiles from the Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp platform. We retrieved N2O profiles using IASI clear sky radiances in 2 spectral bands: B1 and B2 centered at ∼ 1280 cm−1 and ∼ 2220 cm−1, respectively. Both retrievals in B1 and B2 (hereafter referred to as N2O_B1 and N2O_B2, respectively) are sensitive to the mid-to-upper troposphere with a maximum of sensitivity at around 309 hPa. The degrees of freedom for N2O_B1 and N2O_B2 are 1.38 and 0.93, respectively. We validated the retrievals using the High-performance Instrumented Airborne Platform for Environmental Research Pole-to-Pole Observations (HIPPO). The comparisons between HIPPO and the two retrieved datasets show relatively low standard deviation errors around 1.5 % (∼ 4.8 ppbv) and 1.0 % (∼ 3.2 ppbv) for N2O_B1 and N2O_B2, respectively. However, the impact of H2O contamination on N2O_B1 due to its strong absorption bands in B1 significantly degrades the quality of the retrievals in tropical regions. We analysed the scientific consistency of the retrievals at 309 hPa with a focus on the long-range transport of N2O especially during the Asian summer monsoon. Over the mid-latitude regions, both variations of N2O_B1 and N2O_B2 at 309 hPa are influenced by the stratospheric N2O-depleted air because of the relative coarse shape of the averaging kernel. The analysis of N2O_B2 using results from backtrajectories exhibits the capacity of these retrievals to capture long-range transport of air masses from Asia to northern Africa via the summer monsoon anticyclone on a daily basis. Thus, N2O_B1 and N2O_B2 offer an unprecedented possibility to study global upper tropospheric N2O on a daily basis.

scholarly journals Measurement report: Long-range transport patterns into the tropical northwest Pacific during the CAMP<sup>2</sup>Ex aircraft campaign: chemical composition, size distributions, and the impact of convection

2021 ◽  
Vol 21 (5) ◽  
pp. 3777-3802
Author(s):  
Miguel Ricardo A. Hilario ◽  
Ewan Crosbie ◽  
Michael Shook ◽  
Jeffrey S. Reid ◽  
Maria Obiminda L. Cambaliza ◽  
...  
Keyword(s):  
Long Range ◽  
Southwest Monsoon ◽  
Long Range Transport ◽  
Northwest Pacific ◽  
Back Trajectories ◽  
Air Masses ◽  
China Sea ◽  
Range Transport ◽  
Transport Patterns ◽  
The Impact

Abstract. The tropical Northwest Pacific (TNWP) is a receptor for pollution sources throughout Asia and is highly susceptible to climate change, making it imperative to understand long-range transport in this complex aerosol-meteorological environment. Measurements from the NASA Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex; 24 August to 5 October 2019) and back trajectories from the National Oceanic and Atmospheric Administration Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) were used to examine transport into the TNWP from the Maritime Continent (MC), peninsular Southeast Asia (PSEA), East Asia (EA), and the West Pacific (WP). A mid-campaign monsoon shift on 20 September 2019 led to distinct transport patterns between the southwest monsoon (SWM; before 20 September) and monsoon transition (MT; after 20 September). During the SWM, long-range transport was a function of southwesterly winds and cyclones over the South China Sea. Low- (high-) altitude air generally came from MC (PSEA), implying distinct aerosol processing related to convection and perhaps wind shear. The MT saw transport from EA and WP, driven by Pacific northeasterly winds, continental anticyclones, and cyclones over the East China Sea. Composition of transported air differed by emission source and accumulated precipitation along trajectories (APT). MC air was characterized by biomass burning tracers while major components of EA air pointed to Asian outflow and secondary formation. Convective scavenging of PSEA air was evidenced by considerable vertical differences between aerosol species but not trace gases, as well as notably higher APT and smaller particles than other regions. Finally, we observed a possible wet scavenging mechanism acting on MC air aloft that was not strictly linked to precipitation. These results are important for understanding the transport and processing of air masses with further implications for modeling aerosol lifecycles and guiding international policymaking to public health and climate, particularly during the SWM and MT.

scholarly journals Ground-based and satellite optical investigation of the atmosphere and surface of Antarctica

2018 ◽  
Vol 176 ◽  
pp. 10006
Author(s):  
Aleksey Malinka ◽  
Luc Blarel ◽  
Ludmila Chaikovskaya ◽  
Anatoli Chaikovsky ◽  
Natalia Denishchik-Nelubina ◽  
...  
Keyword(s):  
Snow Cover ◽  
Long Range ◽  
Climate Changes ◽  
Atmospheric Pollutants ◽  
Long Range Transport ◽  
Optical Investigation ◽  
Aerosol Cloud ◽  
Range Transport ◽  
The Antarctic

This presentation contains the results of the 10-year research of Belarusian Antarctic expeditions. The set of instruments consists of a lidar, an albedometer, and a scanning sky radiometer CIMEL. Besides, the data from satellite radiometer MODIS were used to characterize the snow cover. The works focus on the study of aerosol, cloud and snow characteristics in the Antarctic, and their links with the long range transport of atmospheric pollutants and climate changes.

scholarly journals Evaluating the influences of biomass burning during 2006 BASE-ASIA: a regional chemical transport modeling

2012 ◽  
Vol 12 (9) ◽  
pp. 3837-3855 ◽  
Author(s):  
J. S. Fu ◽  
N. C. Hsu ◽  
Y. Gao ◽  
K. Huang ◽  
C. Li ◽  
...  
Keyword(s):  
Southeast Asia ◽  
East Asia ◽  
Long Range ◽  
Biomass Burning ◽  
Cross Sections ◽  
Southern China ◽  
Source Region ◽  
Long Range Transport ◽  
Range Transport ◽  
The Impact

Abstract. To evaluate the impact of biomass burning from Southeast Asia to East Asia, this study conducted numerical simulations during NASA's 2006 Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment (BASE-ASIA). Two typical episode periods (27–28 March and 13–14 April) were examined. Two emission inventories, FLAMBE and GFED, were used in the simulations. The influences during two episodes in the source region (Southeast Asia) contributed to the surface CO, O3 and PM2.5 concentrations as high as 400 ppbv, 20 ppbv and 80 μg m−3, respectively. The perturbations with and without biomass burning of the above three species during the intense episodes were in the range of 10 to 60%, 10 to 20% and 30 to 70%, respectively. The impact due to long-range transport could spread over the southeastern parts of East Asia and could reach about 160 to 360 ppbv, 8 to 18 ppbv and 8 to 64 μg m−3 on CO, O3 and PM2.5, respectively; the percentage impact could reach 20 to 50% on CO, 10 to 30% on O3, and as high as 70% on PM2.5. In March, the impact of biomass burning mainly concentrated in Southeast Asia and southern China, while in April the impact becomes slightly broader and even could go up to the Yangtze River Delta region. Two cross-sections at 15° N and 20° N were used to compare the vertical flux of biomass burning. In the source region (Southeast Asia), CO, O3 and PM2.5 concentrations had a strong upward transport from surface to high altitudes. The eastward transport becomes strong from 2 to 8 km in the free troposphere. The subsidence process during the long-range transport contributed 60 to 70%, 20 to 50%, and 80% on CO, O3 and PM2.5, respectively to surface in the downwind area. The study reveals the significant impact of Southeastern Asia biomass burning on the air quality in both local and downwind areas, particularly during biomass burning episodes. This modeling study might provide constraints of lower limit. An additional study is underway for an active biomass burning year to obtain an upper limit and climate effects.

Air Quality Forecast Verification Using Satellite Data

2008 ◽  
Vol 47 (2) ◽  
pp. 425-442 ◽  
Author(s):  
S. Kondragunta ◽  
P. Lee ◽  
J. McQueen ◽  
C. Kittaka ◽  
A. I. Prados ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Long Range ◽  
Regional Scale ◽  
The United States ◽  
Long Range Transport ◽  
Forecast Performance ◽  
Air Quality Forecast ◽  
Time Period ◽  
Range Transport

Abstract NOAA’s operational geostationary satellite retrievals of aerosol optical depths (AODs) were used to verify National Weather Service developmental (research mode) particulate matter (PM2.5) predictions tested during the summer 2004 International Consortium for Atmospheric Research on Transport and Transformation/New England Air Quality Study (ICARTT/NEAQS) field campaign. The forecast period included long-range transport of smoke from fires burning in Canada and Alaska and a regional-scale sulfate event over the Gulf of Mexico and the eastern United States. Over the 30-day time period for which daytime hourly forecasts were compared with observations, the categorical (exceedance defined as AOD &gt; 0.55) forecast accuracy was between 0% and 20%. Hourly normalized mean bias (forecasts − observations) ranged between −50% and +50% with forecasts being positively biased when observed AODs were small and negatively biased when observed AODs were high. Normalized mean errors are between 50% and 100% with the errors on the lower end during the 18–22 July 2004 time period when a regional-scale sulfate event occurred. Spatially, the errors are small over the regions where sulfate plumes were present. The correlation coefficient also showed similar features (spatially and temporally) with a peak value of ∼0.6 during the 18–22 July 2004 time period. The dominance of long-range transport of smoke into the United States during the summer of 2004, neglected in the model predictions, skewed the model forecast performance. Enhanced accuracy and reduced normalized mean errors during the time period when a sulfate event prevailed show that the forecast system has skill in predicting PM2.5 associated with urban/industrial pollution events.

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