scholarly journals Year-round record of near-surface ozone and O<sub>3</sub> enhancement events (OEEs) at Dome A, East Antarctica

2020 ◽  
Author(s):  
Minghu Ding ◽  
Biao Tian ◽  
Michael Ashley ◽  
Zhenxi Zhu ◽  
Lifan Wang ◽  
...  
Keyword(s):  
Surface Ozone ◽  
Dominant Factor ◽  
Back Trajectory ◽  
Dome A ◽  
Polar Night ◽  
Near Surface ◽  
Mean Values ◽  
Back Trajectory Analysis ◽  
Stratospheric Intrusion ◽  
Surface O3

Abstract. To evaluate the characteristics of near-surface O3 over Dome A (Kunlun Station), which is located at the summit of the east Antarctic Ice Sheet, continuous observations were carried out in 2016. Together with observations from the Amundsen–Scott Station (South Pole) and Zhongshan Station, the seasonal and diurnal O3 variabilities were investigated. The results showed different patterns between coastal and inland Antarctic areas that were characterized by high concentrations in cold seasons and at night. The annual mean values at the three stations were 29.19 ± 7.52 ppb, 29.94 ± 4.97 ppb and 24.06 ± 5.79 ppb. Then, specific atmospheric processes, including synoptic-scale air mass transport, were analysed by Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back-trajectory analysis and the potential source contribution function (PSCF) model. Long-range transport was found to account for the O3 enhancement events (OEEs) during summer at Dome A, rather than efficient local production (consistent with previous studies in inland Antarctica). In addition, we observed OEEs during the polar night in the Dome A region, which was not previously found in Antarctica. To explain this unique finding, the occurrence of stratospheric intrusion (stratosphere-to-troposphere, STT) events was studied with the Stratosphere-to-Troposphere Exchange Flux (STEFLUX) tool. This finding suggested that STT events occurred frequently over Dome A and could account for 55 % of the total polar night period. The occurrence probability of OEEs agreed well with STT events, indicating that the STT process was the dominant factor affecting the near-surface O3 over Dome A in the absence of photochemical reaction sources during polar night. This work provides unique information on ozone variation at Dome A and expands our knowledge regarding such events in Antarctica.

scholarly journals Year-round record of near-surface ozone and O<sub>3</sub> enhancement events (OEEs) at Dome A, East Antarctica

2020 ◽  
Vol 12 (4) ◽  
pp. 3529-3544
Author(s):  
Minghu Ding ◽  
Biao Tian ◽  
Michael C. B. Ashley ◽  
Davide Putero ◽  
Zhenxi Zhu ◽  
...  
Keyword(s):  
Mass Transport ◽  
Trajectory Analysis ◽  
Back Trajectory ◽  
Synoptic Scale ◽  
Dome A ◽  
Near Surface ◽  
Air Mass ◽  
Atmospheric Processes ◽  
Back Trajectory Analysis ◽  
Stratospheric Intrusion

Abstract. Dome A, the summit of the East Antarctic Ice Sheet, is an area challenging to access and is one of the harshest environments on Earth. Up until recently, long-term automated observations from Dome A (DA) were only possible with very low power instruments such as a basic meteorological station. To evaluate the characteristics of near-surface O3, continuous observations were carried out in 2016. Together with observations at the Amundsen–Scott Station (South Pole – SP) and Zhongshan Station (ZS, on the southeast coast of Prydz Bay), the seasonal and diurnal O3 variabilities were investigated. The results showed different patterns between coastal and inland Antarctic areas that were characterized by high concentrations in cold seasons and at night. The annual mean values at the three stations (DA, SP and ZS) were 29.2±7.5, 29.9±5.0 and 24.1±5.8 ppb, respectively. We investigated the effect of specific atmospheric processes on near-surface summer O3 variability, when O3 enhancement events (OEEs) are systematically observed at DA (average monthly frequency peaking at up to 64.5 % in December). As deduced by a statistical selection methodology, these O3 enhancement events (OEEs) are affected by significant interannual variability, both in their average O3 values and in their frequency. To explain part of this variability, we analyzed the OEEs as a function of specific atmospheric processes: (i) the role of synoptic-scale air mass transport over the Antarctic Plateau was explored using the Lagrangian back-trajectory analysis Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) method, and (ii) the occurrence of “deep” stratospheric intrusion events was investigated using the Lagrangian tool STEFLUX. The specific atmospheric processes, including synoptic-scale air mass transport, were analyzed by the HYSPLIT back-trajectory analysis and the potential source contribution function (PSCF) model. Short-range transport accounted for the O3 enhancement events (OEEs) during summer at DA, rather than efficient local production, which is consistent with previous studies of inland Antarctica. Moreover, the identification of recent (i.e., 4 d old) stratospheric-intrusion events by STEFLUX suggested that deep events only had a minor influence (up to 1.1 % of the period, in August) on deep events during the variability in near-surface summer O3 at DA. The deep events during the polar night were significantly higher than those during the polar day. This work provides unique data on ozone variation at DA and expands our knowledge of such events in Antarctica. Data are available at https://doi.org/10.5281/zenodo.3923517 (Ding and Tian, 2020).

scholarly journals Year-round record of near-surface ozone and “O<sub>3</sub> enhancement events” (OEEs) at Dome A ,East Antarctica

2020 ◽  
Author(s):  
Minghu Ding ◽  
Biao Tian ◽  
Michael C. B. Ashley ◽  
Davide Putero ◽  
Zhenxi Zhu ◽  
...  
Keyword(s):  
Mass Transport ◽  
Trajectory Analysis ◽  
Surface Ozone ◽  
Back Trajectory ◽  
Synoptic Scale ◽  
Dome A ◽  
Near Surface ◽  
Air Mass ◽  
Atmospheric Processes ◽  
Back Trajectory Analysis

Abstract. Dome A, the summit of the east Antarctic Ice Sheet, is an area challenging to access and is one of the harshest environments on Earth. Up until recently, long term automated observations from Dome A were only possible with very low power instruments such as a basic meteorological station. To evaluate the characteristics of near-surface O3, continuous observations were carried out in 2016. Together with observations at the Amundsen-Scott Station (South Pole – SP) and Zhongshan Station (ZS, on the southeast coast of Prydz Bay), the seasonal and diurnal O3 variabilities were investigated. The results showed different patterns between coastal and inland Antarctic areas that were characterized by high concentrations in cold seasons and at night. The annual mean values at the three stations (DA, SP and ZS) were 29.2 ± 7.5 ppb, 29.9 ± 5.0 ppb and 24.1 ± 5.8 ppb, respectively. We investigated the effect of specific atmospheric processes on near-surface summer O3 variability, when O3 enhancement events (OEEs) are systematically observed at DA (average monthly frequency peaking up to 64.5 % in December). As deduced by a statistical selection methodology, these O3 enhancement events (OEEs) are affected by a significant interannual variability, both in their average O3 values and in their frequency. To explain part of this variability, we analyzed the OEEs as a function of specific atmospheric processes: (i) the role of synoptic-scale air mass transport over the Antarctic Plateau was explored using the Lagrangian back-trajectory analysis – Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) method and (ii) the occurrence of “deep” stratospheric intrusion events was investigated using the Lagrangian tool STEFLUX. The specific atmospheric processes, including synoptic-scale air mass transport, were analysed by the HYSPLIT back-trajectory analysis and the potential source contribution function (PSCF) model. Short-range transport accounted for the O3 enhancement events (OEEs) during summer at DA, rather than efficient local production, which is consistent with previous studies of inland Antarctica. Moreover, the identification of recent (i.e., 4-day old) stratospheric intrusions events by STEFLUX suggested that “deep” events only had a minor influence (up to 1.1 % of the period, in August) on “deep” events during the variability of near-surface summer O3 at DA. The "deep" events during the polar night were significantly higher than those during the polar day. This work provides unique information on ozone variation at DA and expands our knowledge of such events in Antarctica. Data are available at https://doi.org/10.5281/zenodo.3923517 (Ding et al., 2020).

scholarly journals Tropospheric ozone variations at the Nepal Climate Observatory-Pyramid (Himalayas, 5079 m a.s.l.) and influence of deep stratospheric intrusion events

2010 ◽  
Vol 10 (14) ◽  
pp. 6537-6549 ◽  
Author(s):  
P. Cristofanelli ◽  
A. Bracci ◽  
M. Sprenger ◽  
A. Marinoni ◽  
U. Bonafè ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Radiative Forcing ◽  
Surface Ozone ◽  
Lower Troposphere ◽  
Back Trajectory ◽  
Winter Period ◽  
Systematic Assessment ◽  
Back Trajectory Analysis ◽  
Stratospheric Intrusion ◽  
Tropospheric O3

Abstract. The paper presents the first 2 years of continuous surface ozone (O3) observations and systematic assessment of the influence of stratospheric intrusions (SI) at the Nepal Climate Observatory at Pyramid (NCO-P; 27°57' N, 86°48' E), located in the southern Himalayas at 5079 m a.s.l.. Continuous O3 monitoring has been carried out at this GAW-WMO station in the framework of the Ev-K2-CNR SHARE and UNEP ABC projects since March 2006. Over the period March 2006–February 2008, an average O3 value of 49±12 ppbv (±1δ) was recorded, with a large annual cycle characterized by a maximum during the pre-monsoon (61±9 ppbv) and a minimum during the monsoon (39±10 ppbv). In general, the average O3 diurnal cycles had different shapes in the different seasons, suggesting an important interaction between the synoptic-scale circulation and the local mountain wind regime. Short-term O3 behaviour in the middle/lower troposphere (e.g. at the altitude level of NCO-P) can be significantly affected by deep SI which, representing one of the most important natural input for tropospheric O3, can also influence the regional atmosphere radiative forcing. To identify days possibly influenced by SI at the NCO-P, a specially designed statistical methodology was applied to the time series of observed and modelled stratospheric tracers. On this basis, during the 2-year investigation, 14.1% of analysed days were found to be affected by SI. The SI frequency showed a clear seasonal cycle, with minimum during the summer monsoon (1.2%) and higher values during the rest of the year (21.5%). As suggested by back-trajectory analysis, the position of the subtropical jet stream could play an important role in determining the occurrence of deep SI transport on the southern Himalayas. We estimated the fraction of O3 due to SI at the NCO-P. This analysis led to the conclusion that during SI O3 significantly increased by 27.1% (+13 ppbv) with respect to periods not affected by such events. Moreover, the integral contribution of SI (O3S) to O3 at the NCO-P was also calculated, showing that up to 13.7% of O3 recorded at the measurement site could be possibly attributed to SI. On a seasonal basis, the lowest SI contributions were found during the summer monsoon (less than 0.1%), while the highest were found during the winter period (up to 24.2%). Even considering the rather large uncertainty associated with these estimates, the obtained results indicated that, during non-monsoon periods, high O3 levels could affect NCO-P during SI, thus influencing the variability of tropospheric O3 over the southern Himalayas.

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 Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990–2013

2017 ◽  
Author(s):  
Camilla Andersson ◽  
Heléne Alpfjord ◽  
Lennart Robertson ◽  
Per Erik Karlsson ◽  
Magnuz Engardt
Keyword(s):  
Transport Model ◽  
Linear Trend ◽  
Surface Ozone ◽  
Vegetation Indices ◽  
High Sensitivity ◽  
Anthropogenic Emissions ◽  
Data Sets ◽  
Chemistry Transport Model ◽  
Near Surface ◽  
Surface O3

Abstract. We have constructed two data sets of hourly resolution reanalyzed near-surface ozone (O3) concentrations for the period 1990–2013 for Sweden. Long-term simulations from a chemistry-transport model (CTM) covering Europe were combined with hourly ozone concentration observations at Swedish and Norwegian background measurement sites using data assimilation. The reanalysis data sets show improved performance than the original CTM when compared to independent observations. In one of the reanalyzes we included all available hourly near-surface O3 observations, whilst in the other we carefully selected time-consistent observations in order to avoid introducing artificial trends. Based on the second reanalysis we investigated statistical aspects of the near-surface O3 concentration, focusing on the linear trend over the 24 year period. We show that high near-surface O3 concentrations are decreasing and low O3 concentrations are increasing, which is mirrored by observed improvement of many health and vegetation indices (apart from those with a low threshold). Using the chemistry-transport model we also conducted sensitivity simulations to quantify the causes of the observed change, focusing on three processes: change in hemispheric background, meteorology and anthropogenic emissions (Swedish and other European). The rising low concentrations of near-surface O3 in Sweden are caused by a combination of all three processes, whilst the decrease in the highest O3 concentrations is caused by O3 precursor emissions reductions. While studying the relative impact of anthropogenic emissions changes, we identified systematic differences in the modelled trend compared to observations that must be caused by incorrect trends in the utilised emissions inventory or by too high sensitivity of our model to emissions changes.

scholarly journals Mechanisms controlling surface ozone over East Asia: a multiscale study coupling regional and global chemical transport models

2008 ◽  
Vol 8 (6) ◽  
pp. 20239-20281 ◽  
Author(s):  
M. Lin ◽  
T. Holloway ◽  
T. Oki ◽  
D. G. Streets ◽  
A. Richter
Keyword(s):  
East Asia ◽  
Atmospheric Chemistry ◽  
Rural Areas ◽  
Surface Ozone ◽  
East China ◽  
Monsoon Circulation ◽  
Sharp Drop ◽  
Near Surface ◽  
Photochemical Production ◽  
Surface O3

Abstract. Mechanisms controlling surface ozone (O3) over East Asia are examined using the regional Community Multiscale Air Quality (CMAQ) model at two horizontal scales: 81 km and 27 km. Through sensitivity studies and comparison with recently available satellite data and surface measurements in China and Japan, we find that the O3 budget over East Asia shows complex interactions among photochemical production, regional transport, meteorological conditions, burning of agricultural residues, and global inflows. For example, wintertime surface O3 over northern domain is sensitive to boundary conditions derived from the MOZART (Model for Ozone and Related Tracers) global model, whereas summertime O3 budget is controlled by the competitive processes between photochemical production and monsoonal intrusion of low-O3 marine air masses from tropical Pacific. We find that simulated surface O3 for 2001 does not exhibit the same sharp drop in July and August concentrations that is observed at two mountaintop sites (Tai and Hua) for 2004 and Beijing for 1995–2005. CMAQ sensitivity tests with two widely used photochemical schemes demonstrate that over the industrial areas in East Asia north of 30° N, SAPRC99 produces higher values of mean summertime O3 than CBIV, amounting to a difference of 10 ppb. In addition, analysis of NCEP winds and geopotential heights suggests that southwesterly monsoonal intrusion in central east China is weakened in August 2001 as compared with the climatologically mean for 1980–2005. Further examination of the O3 diurnal cycle at nine Japanese sites shows that boundary layer evolution has an important effect on the vertical mixing of ground-level O3, and error in near surface meteorology might contribute to overprediction of nighttime O3 in urban and rural areas. In conclusion, the uncertainties in simulating cloud activities and convection mixing, Asian monsoon circulation, photochemical production, and nighttime cooling explain why CMAQ with 81 km horizontal scale overpredicts the observed surface O3 in July and August over central east China and central Japan by 5–15 ppb (CBIV) and 15–25 ppb (SAPRC99). The results suggest clear benefits in evaluating atmospheric chemistry over Asia with high resolution regional model.

scholarly journals Measurements of Saharan dust aerosols over the Eastern Mediterranean using elastic backscatter-Raman lidar, spectrophotometric and satellite observations in the frame of the EARLINET project

2005 ◽  
Vol 5 (8) ◽  
pp. 2065-2079 ◽  
Author(s):  
A. Papayannis ◽  
D. Balis ◽  
V. Amiridis ◽  
G. Chourdakis ◽  
G. Tsaknakis ◽  
...  
Keyword(s):  
Eastern Mediterranean ◽  
Mean Value ◽  
Saharan Dust ◽  
Back Trajectory ◽  
Air Mass ◽  
Mean Values ◽  
Dust Aerosols ◽  
Back Trajectory Analysis ◽  
Spectrophotometric Data ◽  
Lidar Ratio

Abstract. We report on the vertical distributions of Saharan dust aerosols over the N.E. Mediterranean region, which were obtained during a typical dust outbreak on August 2000, by two lidar systems located in Athens and Thessaloniki, Greece, in the frame of the European EARLINET project. MODIS and ground sun spectrophotometric data, as well as air-mass backward trajectories confirmed the existence of Saharan dust in the case examined, which was also successfully forecasted by the DREAM dust model. The lidar data analysis for the period 2000-2002 made possible, for the first time, an estimation of the vertical extent of free tropospheric dust layers [mean values of the aerosol backscatter and extinction coefficients and the extinction-to-backscatter ratio (lidar ratio, LR) at 355 nm], as well as a seasonal distribution of Saharan dust outbreaks over Greece, under cloud-free conditions. A mean value of the lidar ratio at 355 nm was obtained over Athens (53±1 sr) and over Thessaloniki (44±2 sr) during the Saharan dust outbreaks. The corresponding aerosol optical thickness (AOT) at 355 nm, in the altitude range 0-5 km, was 0.69±0.12 and 0.65±0.10 for Athens and Thessaloniki, respectively (within the dust layer the AOT was 0.23 and 0.21, respectively). Air-mass back-trajectory analysis performed in the period 2000-2002 for all Saharan dust outbreaks over the N.E. Mediterranean indicated the main pathways followed by the dust aerosols.

scholarly journals Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990–2013

2017 ◽  
Vol 17 (22) ◽  
pp. 13869-13890 ◽  
Author(s):  
Camilla Andersson ◽  
Heléne Alpfjord ◽  
Lennart Robertson ◽  
Per Erik Karlsson ◽  
Magnuz Engardt
Keyword(s):  
Transport Model ◽  
Linear Trend ◽  
Surface Ozone ◽  
Vegetation Indices ◽  
High Sensitivity ◽  
Anthropogenic Emissions ◽  
Data Sets ◽  
Near Surface ◽  
The Impact ◽  
Surface O3

Abstract. We have constructed two data sets of hourly resolution reanalyzed near-surface ozone (O3) concentrations for the period 1990–2013 for Sweden. Long-term simulations from a chemistry-transport model (CTM) covering Europe were combined with hourly ozone concentration observations at Swedish and Norwegian background measurement sites using retrospective variational data analysis. The reanalysis data sets show improved performance over the original CTM when compared to independent observations. In one of the reanalyses, we included all available hourly near-surface O3 observations, whilst in the other we carefully selected time-consistent observations. Based on the second reanalysis we investigated statistical aspects of the distribution of the near-surface O3 concentrations, focusing on the linear trend over the 24-year period. We show that high near-surface O3 concentrations are decreasing and low O3 concentrations are increasing, which is reflected in observed improvement of many health and vegetation indices (apart from those with a low threshold). Using the CTM we also conducted sensitivity simulations to quantify the causes of the observed change, focusing on three factors: change in hemispheric background concentrations, meteorology and anthropogenic emissions. The rising low concentrations of near-surface O3 in Sweden are caused by a combination of all three factors, whilst the decrease in the highest O3 concentrations is caused by European O3 precursor emissions reductions. While studying the impact of anthropogenic emissions changes, we identified systematic differences in the modeled trend compared to observations that must be caused by incorrect trends in the utilized emissions inventory or by too high sensitivity of our model to emissions changes.

Observed variability of Surface Ozone (O3) and its Precursors over the Indian Capital region

2020 ◽  
Author(s):  
Ravi Kumar Kunchala ◽  
Anshika Chandel ◽  
Raju Attada ◽  
Ramesh K Vellore ◽  
Vijay K Soni
Keyword(s):  
Surface Ozone ◽  
Back Trajectory ◽  
Oh Radicals ◽  
Transport Mechanisms ◽  
Study Region ◽  
Atmospheric Lifetime ◽  
Chemical Balance ◽  
Capital Region ◽  
Back Trajectory Analysis ◽  
Management Issues

&lt;p&gt;&lt;span&gt;Ozone (O&lt;sub&gt;3&lt;/sub&gt;) is a greenhouse gas which plays different roles in stratosphere and troposphere. It also has an important role in radiative and chemical balance of the atmosphere, and thus the changes in O&lt;sub&gt;3 &lt;/sub&gt;have greater climatic implications. Although O&lt;sub&gt;3&lt;/sub&gt; is present in trace amounts in troposphere, it is adequate to govern the oxidation processes in the Earth&amp;#8217;s atmosphere by forming OH radicals, as the atmospheric lifetime of many gases is controlled by OH radicals. Rapidly developing countries in tropics and subtropics have realized the importance of tropospheric O&lt;sub&gt;3&lt;/sub&gt; studies as these regions have very limited measurements of ozone and its precursor gases. Understand the variability of the surface O&lt;sub&gt;3 &lt;/sub&gt;and their association with precursors are extremely important for the policy decisions to mitigate the impacts of ozone on human health and crops and ozone air quality management issues in the region. This study investigates the variability of surface ozone (O&lt;sub&gt;3&lt;/sub&gt;) its association with its precursors (NO, NO2, NOX, CO) at time scales of annual, seasonal and diurnal scales for the duration of three years using ground-based observations from IMD Ayanagar, IMD Lodhi road, CRRI, CV Raman, IGI Palam stations in the Indian Capital region. Further, we will present the back-trajectory analysis&amp;#160;to elucidates the transport mechanisms/ pathways on the variability of ozone for the study region. &lt;/span&gt;&lt;/p&gt;

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