scholarly journals Diurnal variability of stratospheric column NO<sub>2</sub> measured using direct solar and lunar spectra over Table Mountain, California (34.38° N)

2021 ◽  
Vol 14 (12) ◽  
pp. 7495-7510
Author(s):  
King-Fai Li ◽  
Ryan Khoury ◽  
Thomas J. Pongetti ◽  
Stanley P. Sander ◽  
Franklin P. Mills ◽  
...  
Keyword(s):  
Los Angeles ◽  
Model Simulation ◽  
Urban Pollution ◽  
Back Trajectory ◽  
Diurnal Variability ◽  
Riverside County ◽  
Back Trajectory Analysis ◽  
Table Mountain ◽  
Abrupt Changes ◽  
Measurement Period

Abstract. A full diurnal measurement of stratospheric column NO2 has been made over the Jet Propulsion Laboratory's Table Mountain Facility (TMF) located in the mountains above Los Angeles, California, USA (2.286 km above mean sea level, 34.38∘ N, 117.68∘ W). During a representative week in October 2018, a grating spectrometer measured the telluric NO2 absorptions in direct solar and lunar spectra. The stratospheric column NO2 is retrieved using a modified minimum-amount Langley extrapolation, which enables us to accurately treat the non-constant NO2 diurnal cycle abundance and the effects of tropospheric pollution near the measurement site. The measured 24 h cycle of stratospheric column NO2 on clean days agrees with a 1-D photochemical model calculation, including the monotonic changes during daytime and nighttime due to the exchange with the N2O5 reservoir and the abrupt changes at sunrise and sunset due to the activation or deactivation of the NO2 photodissociation. The observed daytime NO2 increasing rate is (1.34±0.24)×1014 cm−2 h−1. The observed NO2 in one of the afternoons during the measurement period was much higher than the model simulation, implying the influence of urban pollution from nearby counties. A 24 h back-trajectory analysis shows that the wind first came from inland in the northeast and reached southern Los Angeles before it turned northeast and finally arrived at TMF, allowing it to pick up pollutants from Riverside County, Orange County, and downtown Los Angeles.

scholarly journals Diurnal variability of total column NO<sub>2</sub> measured using direct solar and lunar spectra over Table Mountain, California (34.38° N)

2020 ◽  
Author(s):  
King-Fai Li ◽  
Ryan Khoury ◽  
Thomas J. Pongetti ◽  
Stanley P. Sander ◽  
Yuk L. Yung
Keyword(s):  
Los Angeles ◽  
Model Simulation ◽  
Urban Pollution ◽  
Back Trajectory ◽  
Diurnal Variability ◽  
Riverside County ◽  
Back Trajectory Analysis ◽  
Table Mountain ◽  
Abrupt Changes ◽  
Total Column

Abstract. A full diurnal measurement of total column NO2 has been made over the Jet Propulsion Laboratory’s Table Mountain Facility (TMF) located in the mountains above Los Angeles, California, USA (2.286 km above mean sea level, 34.38° N, 117.68° W). During a representative week in October 2018, a grating spectrometer measured the telluric NO2 absorptions in direct solar and lunar spectra. The total column NO2 is retrieved using a model-based minimum-amount Langley extrapolation, which enables us to accurately treat the non-constant NO2 diurnal cycle abundance and the effects of pollution near the measurement site. The measured 24-hour cycle of total column NO2 on clean days agrees with a 1-D photochemical model calculation, including the monotonic changes during daytime and nighttime due to the exchange with the N2O5 reservoir and the abrupt changes at sunrise and sunset due to the activation or deactivation of the NO2 photodissociation. The observed daytime NO2 increasing rate is (1.29 ± 0.30)×1014 cm−2 h−1. The total column NO2 in one of the afternoons during the measurement period was much higher than the model simulation, implying the influence of urban pollution from nearby cities. A 24-hour back-trajectory analysis shows that the wind first came from inland in the northeast and reached the southern Los Angeles before it turned northeast and finally arrived TMF, allowing it to pick up pollutants from Riverside County, Orange County, and Downtown Los Angeles.

scholarly journals South East Pacific atmospheric composition and variability sampled along 20° S during VOCALS-REx

2011 ◽  
Vol 11 (11) ◽  
pp. 5237-5262 ◽  
Author(s):  
G. Allen ◽  
H. Coe ◽  
A. Clarke ◽  
C. Bretherton ◽  
R. Wood ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Land Surface ◽  
Large Scale ◽  
Trajectory Analysis ◽  
Model Simulation ◽  
Atmospheric Composition ◽  
Back Trajectory ◽  
Free Troposphere ◽  
Back Trajectory Analysis ◽  
East Pacific

Abstract. The VAMOS Ocean-Cloud-Atmosphere-Land Regional Experiment (VOCALS-REx) was conducted from 15 October to 15 November 2008 in the South East Pacific (SEP) region to investigate interactions between land, sea and atmosphere in this unique tropical eastern ocean environment and to improve the skill of global and regional models in representing the region. This study synthesises selected aircraft, ship and surface site observations from VOCALS-REx to statistically summarise and characterise the atmospheric composition and variability of the Marine Boundary Layer (MBL) and Free Troposphere (FT) along the 20° S parallel between 70° W and 85° W. Significant zonal gradients in mean MBL sub-micron aerosol particle size and composition, carbon monoxide, sulphur dioxide and ozone were seen over the campaign, with a generally more variable and polluted coastal environment and a less variable, more pristine remote maritime regime. Gradients in aerosol and trace gas concentrations were observed to be associated with strong gradients in cloud droplet number. The FT was often more polluted in terms of trace gases than the MBL in the mean; however increased variability in the FT composition suggests an episodic nature to elevated concentrations. This is consistent with a complex vertical interleaving of airmasses with diverse sources and hence pollutant concentrations as seen by generalised back trajectory analysis, which suggests contributions from both local and long-range sources. Furthermore, back trajectory analysis demonstrates that the observed zonal gradients both in the boundary layer and the free troposphere are characteristic of marked changes in airmass history with distance offshore – coastal boundary layer airmasses having been in recent contact with the local land surface and remote maritime airmasses having resided over ocean for in excess of ten days. Boundary layer composition to the east of 75° W was observed to be dominated by coastal emissions from sources to the west of the Andes, with evidence for diurnal pumping of the Andean boundary layer above the height of the marine capping inversion. Analysis of intra-campaign variability in atmospheric composition was not found to be significantly correlated with observed low-frequency variability in the large scale flow pattern; campaign-average interquartile ranges of CO, SO2 and O3 concentrations at all longitudes were observed to dominate over much smaller differences in median concentrations calculated between periods of different flow regimes. The campaign climatology presented here aims to provide a valuable dataset to inform model simulation and future process studies, particularly in the context of aerosol-cloud interaction and further evaluation of dynamical processes in the SEP region for conditions analogous to those during VOCALS-REx. To this end, our results are discussed in terms of coastal, transitional and remote spatial regimes in the MBL and FT and a gridded dataset are provided as a resource.

scholarly journals Southeast Pacific atmospheric composition and variability sampled along 20° S during VOCALS-REx

2011 ◽  
Vol 11 (1) ◽  
pp. 681-744 ◽  
Author(s):  
G. Allen ◽  
H. Coe ◽  
A. Clarke ◽  
C. Bretherton ◽  
R. Wood ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Land Surface ◽  
Trajectory Analysis ◽  
Marine Boundary Layer ◽  
Model Simulation ◽  
Cloud Droplet ◽  
Atmospheric Composition ◽  
Back Trajectory ◽  
Free Troposphere ◽  
Back Trajectory Analysis

Abstract. The VAMOS Ocean-Climate-Atmosphere-Land Regional Experiment (VOCALS-REx) was conducted from 15 October to 15 November 2008 in the South East Pacific region to investigate interactions between land, sea and atmosphere in this unique tropical eastern ocean environment and to improve the skill of global and regional models in representing the region. This study synthesises selected aircraft, ship and surface site observations from VOCALS-REx to statistically summarise and characterise the atmospheric composition and variability of the Marine Boundary Layer (MBL) and Free Troposphere (FT) along the 20° S parallel between 70° W and 85° W. Significant zonal gradients in mean MBL sub-micron aerosol particle size and composition, carbon monoxide, ozone and sulphur dioxide were seen over the campaign, with a generally more variable and polluted coastal environment and a less variable, more pristine remote maritime regime. Gradients are observed to be associated with strong gradients in cloud droplet number. The FT is often more polluted in terms of trace gases than the MBL in the mean; however increased variability in the FT composition suggests an episodic nature to elevated concentrations. This is consistent with a complex vertical interleaving of airmasses with diverse sources and hence pollutant concentrations as seen by generalised back trajectory analysis, which suggests contributions from both local and long-range sources. Furthermore, back trajectory analysis demonstrates that the observed zonal gradients both in the boundary layer and the free troposphere are characteristic of marked changes in airmass history with distance offshore – coastal boundary layer airmasses having been in recent contact with the local land surface and remote maritime airmasses having resided over ocean for in excess of ten days. Boundary layer composition to the east of 75° W was observed to be dominated by coastal emissions from sources to the west of the Andes, with evidence for diurnal pumping of the Andean boundary layer above the height of the marine capping inversion. The climatology presented here aims to provide a valuable dataset to inform model simulation and future process studies, particularly in the context of aerosol-cloud interaction and further evaluation of dynamical processes in the SEP region for conditions analogous to those during VOCALS-REx.

scholarly journals Use of Low-Cost Ambient Particulate Sensors in Nablus, Palestine with Application to the Assessment of Regional Dust Storms

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 539
Author(s):  
Abdelhaleem Khader ◽  
Randal S. Martin
Keyword(s):  
Low Cost ◽  
Dust Storms ◽  
Air Pollutant ◽  
World Health ◽  
Back Trajectory ◽  
Hysplit Model ◽  
Air Masses ◽  
Palestinian Territories ◽  
Back Trajectory Analysis ◽  
Lower Elevation

Few air pollutant studies within the Palestinian territories have been reported in the literature. In March–April and May–June of 2018, three low-cost, locally calibrated particulate monitors (AirU’s) were deployed at different elevations and source areas throughout the city of Nablus in Northern West Bank, Palestine. During each of the three-week periods, high but site-to-site similar particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5) and less than 10 µm (PM10) concentrations were observed. The PM2.5 concentrations at the three sampling locations and during both sampling periods averaged 38.2 ± 3.6 µg/m3, well above the World Health Organization’s (WHO) 24 h guidelines. Likewise, the PM10 concentrations exceeded or were just below the WHO’s 24 h guidelines, averaging 48.5 ± 4.3 µg/m3. During both periods, short episodes were identified in which the particulate levels at all three sites increased substantially (≈2×) above the regional baseline. Air mass back trajectory analyses using U.S. National Oceanic and Atmospheric Administration’s (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggested that, during these peak episodes, the arriving air masses spent recent days over desert areas (e.g., the Saharan Desert in North Africa). On days with regionally low PM2.5 concentrations (≈20 µg/m3), back trajectory analysis showed that air masses were directed in from the Mediterranean Sea area. Further, the lower elevation (downtown) site often recorded markedly higher particulate levels than the valley wall sites. This would suggest locally derived particulate sources are significant and may be beneficial in the identification of potential remediation options.

scholarly journals An investigation of processes controlling the evolution of the boundary layer aerosol size distribution properties at the Swedish background station Aspvreten

2004 ◽  
Vol 4 (4) ◽  
pp. 4507-4543 ◽  
Author(s):  
P. Tunved ◽  
J. Ström ◽  
H.-C. Hansson
Keyword(s):  
Size Distribution ◽  
Wet Deposition ◽  
Source Area ◽  
Aerosol Size Distribution ◽  
Back Trajectory ◽  
Main Process ◽  
Size Distributions ◽  
Back Trajectory Analysis ◽  
The One ◽  
Precipitating Clouds

Abstract. Aerosol size distributions have been measured at the Swedish background station Aspvreten (58.8° N, 17.4° E). Different states of the aerosol were determined using a novel application of cluster analysis. The analysis resulted in eight different clusters capturing the different stages of the aerosol lifecycle. The aerosol was interpreted as belonging to fresh, intermediate and aged type of size distribution and different magnitudes thereof. With aid of back trajectory analysis we present statistics concerning the relation of source area and different meteorological parameters using a non-lagrangian approach. Source area is argued to be important although not sufficient to describe the observed aerosol properties. Especially processing by clouds and precipitation is shown to be crucial for the evolution of the aerosol size distribution. As much as 60% of the observed size distributions present features likely related to cloud processes or wet deposition. The lifetime properties of different sized aerosols are discussed by means of measured variability. Processing by non-precipitating clouds most obviously affect aerosols in the size range 100 nm and larger. This indicates an approximate limit for activation in clouds to 100 nm in this type of environment. The aerosol lifecycle is discussed. Size distributions bearing signs of recent new particle formation (~30% of the observed size distributions) represent the first stage in the lifecycle. Aging may proceed in two directions: either growth by condensation and coagulation or processing by non-precipitating clouds. In both cases mass is accumulated. Wet removal is the main process capable of removing aerosol mass. Wet deposition is argued to be an important mechanism in reaching a state where nucleation may occur (i.e. sufficiently low aerosol surface area) in environments similar to the one studied.

scholarly journals Airborne microplastic particles detected in the remote marine atmosphere

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Miri Trainic ◽  
J. Michel Flores ◽  
Iddo Pinkas ◽  
Maria Luiza Pedrotti ◽  
Fabien Lombard ◽  
...  
Keyword(s):  
North Atlantic ◽  
Trajectory Analysis ◽  
North Atlantic Ocean ◽  
Anthropogenic Pollution ◽  
Terminal Velocity ◽  
Back Trajectory ◽  
Marine Atmosphere ◽  
Local Production ◽  
The North ◽  
Back Trajectory Analysis

AbstractAnthropogenic pollution from marine microplastic particles is a growing concern, both as a source of toxic compounds, and because they can transport pathogens and other pollutants. Airborne microplastic particles were previously observed over terrestrial and coastal locations, but not in the remote ocean. Here, we collected ambient aerosol samples in the North Atlantic Ocean, including the remote marine atmosphere, during the Tara Pacific expedition in May-June 2016, and chemically characterized them using micro-Raman spectroscopy. We detected a range of airborne microplastics, including polystyrene, polyethylene, polypropylene, and poly-silicone compounds. Polyethylene and polypropylene were also found in seawater, suggesting local production of airborne microplastic particles. Terminal velocity estimations and back trajectory analysis support this conclusion. For technical reasons, only particles larger than 5 µm, at the upper end of a typical marine atmospheric size distribution, were analyzed, suggesting that our analyses underestimate the presence of airborne microplastic particles in the remote marine atmosphere.

scholarly journals Spatial characteristics of aerosol physical properties over the northeastern parts of peninsular India

2005 ◽  
Vol 23 (10) ◽  
pp. 3219-3227 ◽  
Author(s):  
K. Niranjan ◽  
B. Melleswara Rao ◽  
P. S. Brahmanandam ◽  
B. L. Madhavan ◽  
V. Sreekanth ◽  
...  
Keyword(s):  
Physical Properties ◽  
Particle Growth ◽  
Back Trajectory ◽  
Peninsular India ◽  
Near Surface ◽  
Surface Mass ◽  
Accumulation Mode ◽  
Back Trajectory Analysis ◽  
Aerosol Mass ◽  
Northern Latitudes

Abstract. Measurements on aerosol spectral optical depths and near surface mass-size distributions made at several locations in the states of Andhra Pradesh, Orissa and Chattisgarh, constituting the northeastern part of the peninsular India during the ISRO-GBP land campaign-I show significant regional variations in aerosol physical properties. Higher spectral optical depths were observed in the coastal regions and over southern latitudes compared to interior continental regions and northern latitudes. The optical depths, size index "α" and the near surface aerosol mass concentrations indicate a relative abundance of nucleation mode aerosols in the northern latitudes, in contrast to the dominance of the accumulation mode aerosols at the eastern coastal and southern latitudes. The airmass pathways derived from the back trajectory analysis indicate that the higher aerosol population in the accumulation mode, and consequently the higher optical depths in the southern locations, could be due to the transport of aerosol from the polluted north Indian regions via the oceanic region over the Bay of Bengal, where significant particle growth is expected, increasing the population of accumulation mode aerosols over these regions.

scholarly journals Long-Term Observation of Atmospheric Speciated Mercury during 2007–2018 at Cape Hedo, Okinawa, Japan

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 362 ◽  
Author(s):  
Kohji Marumoto ◽  
Noriyuki Suzuki ◽  
Yasuyuki Shibata ◽  
Akinori Takeuchi ◽  
Akinori Takami ◽  
...  
Keyword(s):  
Elemental Mercury ◽  
Cold Season ◽  
Global Scale ◽  
Back Trajectory ◽  
Asian Continent ◽  
Okinawa Island ◽  
Gaseous Elemental Mercury ◽  
The North ◽  
Back Trajectory Analysis ◽  
North Edge

The concentrations of atmospheric gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (particles with diameter smaller than 2.5 μm; PBM2.5) were continuously observed for a period of over 10 years at Cape Hedo, located on the north edge of Okinawa Island on the border of the East China Sea and the Pacific Ocean. Regional or global scale mercury (Hg) pollution affects their concentrations because no local stationary emission sources of Hg exist near the observation site. Their concentrations were lower than those at urban and suburban cities, as well as remote sites in East Asia, but were slightly higher than the background concentrations in the Northern Hemisphere. The GEM concentrations exhibited no diurnal variations and only weak seasonal variations, whereby concentrations were lower in the summer (June–August). An annual decreasing trend for GEM concentrations was observed between 2008 and 2018 at a rate of −0.0382 ± 0.0065 ng m−3 year−1 (−2.1% ± 0.36% year−1) that was the same as those in Europe and North America. Seasonal trend analysis based on daily median data at Cape Hedo showed significantly decreasing trends for all months. However, weaker decreasing trends were observed during the cold season from January to May, when air masses are easily transported from the Asian continent by westerlies and northwestern monsoons. Some GEM, GOM, and PBM2.5 pollution events were observed more frequently during the cold season. Back trajectory analysis showed that almost all these events occurred due to the substances transported from the Asian continent. These facts suggested that the decreasing trend observed at Cape Hedo was influenced by the global decreasing GEM trend, but the rates during the cold season were restrained by regional Asian outflows. On the other hand, GOM concentrations were moderately controlled by photochemical production in summer. Moreover, both GOM and PBM2.5 concentrations largely varied during the cold season due to the influence of regional transport rather than the trend of atmospheric Hg on a global scale.

Sign in / Sign up

Export Citation Format

Share Document