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 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 Ozone and carbon monoxide over India during the summer monsoon: regional emissions and transport

2016 ◽  
Vol 16 (5) ◽  
pp. 3013-3032 ◽  
Author(s):  
Narendra Ojha ◽  
Andrea Pozzer ◽  
Armin Rauthe-Schöch ◽  
Angela K. Baker ◽  
Jongmin Yoon ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Long Range ◽  
Summer Monsoon ◽  
Lower Troposphere ◽  
Southern India ◽  
Long Range Transport ◽  
Minor Role ◽  
Air Masses ◽  
Range Transport ◽  
Regional Emissions

Abstract. We compare in situ measurements of ozone (O3) and carbon monoxide (CO) profiles from the CARIBIC program with the results from the regional chemistry transport model (WRF-Chem) to investigate the role of local and regional emissions and long-range transport over southern India during the summer monsoon of 2008. WRF-Chem successfully reproduces the general features of O3 and CO distributions over the South Asian region. However, absolute CO concentrations in the lower troposphere are typically underestimated. Here we investigate the influence of local relative to remote emissions through sensitivity simulations. The influence of 50 % increased CO emissions over South Asia leads to a significant enhancement (upto 20 % in July) in upper tropospheric CO in the northern and central Indian regions. Over Chennai in southern India, this causes a 33 % increase in surface CO during June. However, the influence of enhanced local and regional emissions is found to be smaller (5 %) in the free troposphere over Chennai, except during September. Local to regional emissions are therefore suggested to play a minor role in the underestimation of CO by WRF-Chem during June–August. In the lower troposphere, a high pollution (O3: 146.4 ± 12.8, CO: 136.4 ± 12.2 nmol mol−1) event (15 July 2008), not reproduced by the model, is shown to be due to transport of photochemically processed air masses from the boundary layer in southern India. A sensitivity simulation combined with backward trajectories indicates that long-range transport of CO to southern India is significantly underestimated, particularly in air masses from the west, i.e., from Central Africa. This study highlights the need for more aircraft-based measurements over India and adjacent regions and the improvement of global emission inventories.

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 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 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 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.

scholarly journals Impact of transatlantic transport episodes on summertime ozone in Europe

2006 ◽  
Vol 6 (8) ◽  
pp. 2057-2072 ◽  
Author(s):  
G. Guerova ◽  
I. Bey ◽  
J.-L. Attié ◽  
R. V. Martin ◽  
J. Cui ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Long Range ◽  
North American ◽  
Tropospheric Chemistry ◽  
Long Range Transport ◽  
Back Trajectory ◽  
Pollution Transport ◽  
Upper Troposphere ◽  
Range Transport ◽  
The Impact

Abstract. This paper reports on the transport of ozone (O3) and related species over the North Atlantic ocean and its impact on Europe. Measurements of nitrogen dioxide (NO2) and carbon monoxide (CO) columns from the GOME and MOPITT satellite instruments, respectively, are used in conjunction with the GEOS-CHEM global model of transport and tropospheric chemistry to identify the major events of long range transport that reach Europe over the course of summer 2000. Sensitivity model simulations are used to analyse observed O3 distributions with respect to the impact of long range transport events. For that purpose, we used in-situ O3 observations taken at the mountain site of Jungfraujoch as well as O3 vertical profiles taken in the vicinity of central European cities. Over the course of summer 2000, we identified 9 major episodes of transatlantic pollution transport; 7 events are associated with transient cyclones while 2 events occur through zonal transport (e.g. by advection in the strong low-level westerly winds established in summer between the Azores anticyclone and transient cyclones). We find that on average three episodes occur per month with the strongest ones being in June. The number and frequency of long range transport events that reach Europe are driven by the position and strength of the Azores anticyclone. Model sensitivity simulations indicate that the summer mean North American O3 contribution ranges from 3 to 5 ppb (7–11%) in the planetary boundary layer and 10 to 13 ppb (18–23%) in the middle and upper troposphere. During particular episodes, North American sources can result in O3 enhancements up to 25–28 ppb in the layer between 800–600 hPa and 10–12 ppb in the boundary layer. The impact of the zonal transport events on O3 distribution over Europe is more clearly seen below 700 hPa as they tend to transport pollution at lower levels while the events associated with transient cyclones are more likely to have an impact on the middle and upper troposphere (i.e. above 600 hPa). The air mass origins found in the GEOS-CHEM model are clearly confirmed by back trajectory analyses. During most of the 9 events, a strong contribution in North American O3 is in general associated with only little European O3 and vice-versa (in particular at the Jungfraujoch). A substantial North American contribution (e.g., 30% or higher) to O3 over Europe does not always result in pronounced O3 enhancements in the observations during our period of study.

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