scholarly journals Comparison of emission data and the backward trajectory analysis from airborne observation for East Asia

2003 ◽  
Vol 11 ◽  
pp. 133-138
Author(s):  
Gakuji KURATA ◽  
Toshihiro KITADA ◽  
Kouhei YAMAMOTO ◽  
Gregory R. CARMICHAEL ◽  
Youhua TANG
Keyword(s):  
East Asia ◽  
Trajectory Analysis ◽  
Backward Trajectory ◽  
Emission Data

scholarly journals Comparison of the RADM2 and RACM chemical mechanisms in O3 simulations: effect of the photolysis rate constant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chien-Hung Chen ◽  
Tu-Fu Chen ◽  
Shang-Ping Huang ◽  
Ken-Hui Chang
Keyword(s):  
East Asia ◽  
Rate Constants ◽  
Daily Maximum ◽  
Bias Error ◽  
Air Quality Model ◽  
Quality Model ◽  
Yield Data ◽  
Emission Data ◽  
Photolysis Rate ◽  
Photolysis Rates

AbstractSince the photolysis rate plays an important role in any photoreaction leading to compound sink and radical formation/destruction and eventually O3 formation, its impact on the simulated O3 concentration was evaluated in the present study. Both RADM2 and RACM were adopted with and without updated photolysis rate constants. The newly developed photolysis rates were determined based on two major absorption cross-section and quantum yield data sources. CMAQ in conjunction with meteorological MM5 and emission data retrieved from Taiwan and East Asia were employed to provide spatial and temporal O3 predictions over a one-week period in a three-level nested domain [from 81 km × 81 km in Domain 1 (East Asia) to 9 km × 9 km in Domain 3 (Taiwan)]. Four cases were analyzed, namely, RADM2, with the original photolysis rates applied in Case 1 as a reference case, RADM2, with the updated photolysis rates applied in Case 2, and RACM, with and without the updated photolysis rates applied in Cases 3 and 4, respectively. A comparison of the simulation and observed results indicates that both the application of updated photolysis rate constants and RACM instead of RADM2 enhanced all three error analysis indicators (unpaired peak prediction accuracy, mean normalized bias error and mean absolute normalized gross error). Specifically, RADM2 with the updated photolysis rates resulted in an increase of 12 ppb (10%) in the daily maximum O3 concentration in southwestern Taiwan, while RACM without the updated photolysis rates resulted in an increase of 20 ppb (17%) in the daily maximum O3 concentration in the same area. When RACM with the updated photolysis rate constants was applied in the air quality model, the difference in the daily maximum O3 concentration reached up to 30 ppb (25%). The implication of Case 4 (RACM with the updated photolysis rates) for the formation and degradation of α-pinene and d-limonene was examined.

scholarly journals Characterization of Regional Influence of Fine Carbonaceous Particles at Gosan, Korea

2018 ◽  
pp. 165-179
Author(s):  
K. J. Moon ◽  
B. J. Kong ◽  
J. S. Han ◽  
Y. S. Ghim
Keyword(s):  
Chemical Composition ◽  
Trajectory Analysis ◽  
Elemental Carbon ◽  
North China ◽  
Fine Particles ◽  
Carbonaceous Aerosol ◽  
Carbonaceous Materials ◽  
Backward Trajectory ◽  
Source Regions ◽  
Secondary Aerosols

Aims: This study aimed to study the long-range transport of anthropogenic carbonaceous aerosol at Gosan, Korea Study Design: Chemical composition of fine particles (aerodynamic diameter < 2.5㎛) and PAHs of TSP measured at Gosan during six intensive measurement periods covering four seasons. And the chemical characteristics of particulate matter were classified and compared each other according to the major source areas identified by using backward trajectory analysis in order to study the impact of distant source regions on the carbonaceous aerosol at Gosan, Korea. Place and Duration of Study: Sample: Gosan, Jeju Island in Republic of Korea, from 13 to 25 Nov. 2001, from 29 Mar. to 11 Apr. 2002, from 27 Aug. to 11 Sep. 2002, from 14 to 26 Feb 2003, from 6 to 22 Jun. 2003, and from 18 Aug. to 1 Sep. 2003. Methodology: In order to investigate the chemical composition of fine particles, 7 major ion components, 21 trace elements, organic and elemental carbon of PM2.5 were measured. In addition, particulate hazardous pollutants including 17 polycyclic aromatic hydrocarbons (PAHs) were analyzed. The measured data were classified according to the dominant source area identified with the three-day backward trajectory analysis. Then several ratios of species combining EC, OC, SO42-, K+ and PAH compounds were used to identify potential sources of carbonaceous materials. Results: Quite different characteristic in the chemical composition of fine particles was observed by regional groups of backward trajectories. Concentrations of ion components including secondary aerosol such as SO42- and NH4+ were relatively high when air masses were originated from north China. Concentrations of OC and gaseous PAHs were higher when they transported from Japan than from other source regions. High concentrations of secondary aerosols as well as particulate PAHs were observed in the air mass from north China with a higher correlation between them. Elemental carbon had a better correlation in this case not only with secondary aerosols, but also with OC and CO, implying that carbonaceous materials were originated from long-distance combustion sources. Especially positive correlation with benzo(ghi)perylene suggested that they also had a vehicular origin. Conclusion: The results showed that biomass burning and vehicular emissions mainly influenced ambient fine particles when they derived from north China and the Korea peninsula while fossil fuel combustion chiefly affected them when they originated in south China during six intensive measurement periods.

scholarly journals Towards precipitation enhancement through cloud seeding in Kenya

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Joshua Ngaina ◽  
Nzioka Muthama ◽  
Joseph Ininda ◽  
Alfred Opere ◽  
Bethwel Mutai
Keyword(s):  
Time Series ◽  
Trajectory Analysis ◽  
Lake Victoria ◽  
Western Indian Ocean ◽  
Cloud Seeding ◽  
Lake Victoria Basin ◽  
Backward Trajectory ◽  
Mean Sea Level ◽  
Precipitation Enhancement ◽  
Cloud Top Temperature

The study investigated potential of enhancing precipitation through cloud seeding during October-November-December (OND) season. Rainfall, cloud top temperature (CTT), aerosol optical depth (AOD) and wind data were used. Short-Cut Bartlett correlation, composite wind and time series analysis, and HYSPLIT backward trajectory analysis were used to achieve the objectives of study. Precipitation showed decreasing patterns with peaks between pentad 65 and 68. Delineated dry years (18) exceeded wet years (9). Low level winds were predominantly north-easterly during dry years characterized by continental trajectory. AOD values increased in all stations during dry year with aerosol load being higher in areas characterized by depressed rainfall. Pollutants suspended 1000 above mean sea level (AMSL) originated from Arabian and India subcontinent and pollutants suspended below 1000 AMSL were predominantly south easterly during wet years originated from Western Indian Ocean and characterized by maritime trajectory. Mean CTT during dry/wet years were positve over coastal areas while central, Rift-valley and Lake Victoria basin showed negative values, indicating presence of seedable conditions and thus potential cloud seeding to enhance rainfall and alleviate existing water stress.

scholarly journals Optimization of stepwise clustering algorithm in backward trajectory analysis

2018 ◽  
Vol 32 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Chunsheng Fang ◽  
Jialu Gao ◽  
Dali Wang ◽  
Diansheng Wang ◽  
Ju Wang
Keyword(s):  
Trajectory Analysis ◽  
Clustering Algorithm ◽  
Backward Trajectory

scholarly journals BACKWARD TRAJECTORY ANALYSIS OF AIR POLUTANTS MEASURED AT BARROW, ALASKA

2002 ◽  
Vol 10 ◽  
pp. 209-214
Author(s):  
Toshiaki SHITABA ◽  
Naoto MURAO ◽  
Sachio OHTA ◽  
Sadamu YAMAGATA
Keyword(s):  
Trajectory Analysis ◽  
Backward Trajectory

scholarly journals Characteristics and sources of atmospheric pollutants in typical inland cities in arid regions of central Asia: A case study of Urumqi city

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249563
Author(s):  
Zongying Li ◽  
Yao Wang ◽  
Zhonglin Xu ◽  
Yue’e Cao
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Central Asia ◽  
Air Pollutants ◽  
Trajectory Analysis ◽  
Atmospheric Pollutants ◽  
Observation Data ◽  
Backward Trajectory ◽  
Concentration Changes ◽  
Co Concentrations

The arid zone of central Asia secluded inland and has the typical features of the atmosphere. Human activities have had a significant impact on the air quality in this region. Urumqi is a key city in the core area of the Silk Road and an important economic center in Northwestern China. The urban environment is playing an increasingly important role in regional development. To study the characteristics and influencing factors of the main atmospheric pollutants in Urumqi, this study selected Urumqi’s daily air quality index (AQI) data and observation data of six major pollutants including fine particulate matter (PM2.5), breathable particulate matter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3_8h) from 2014 to 2018 in conjunction with meteorological data to use a backward trajectory analysis method to study the main characteristics of atmospheric pollutants and their sources in Urumqi from 2014 to 2018. The results showed that: (1) From 2014 to 2018, the annual average of PM2.5, PM10, SO2, NO2 and CO concentrations showed a downward trend, and O3_8h concentrations first increased, then decreased, and then increased, reaching the highest value in 2018 (82.15 μg·m-3); The seasonal changes of PM2.5, PM10, SO2, NO2 and CO concentrations were characterized by low values in summer and fall seasons and high values in winter and spring seasons. The concentration of O3_8h, however, was in the opposite trend, showing the high values in summer and fall seasons, and low values in winter and spring seasons. From 2014 to 2018, with the exception of O3_8h, the concentration changes of the other five major air pollutants were high in December, January, and February, and low in May, June, and July; the daily changes showed a “U-shaped” change during the year. The high-value areas of the "U-shaped" mode formed around the 50th day and the 350th day. (2) The high-value area of AQI was from the end of fall (November) to the beginning of the following spring (March), and the low-value area was from April to October. It showed a U-shaped change trend during the year and the value was mainly distributed between 50 and 100. (3) The concentrations of major air pollutants in Urumqi were significantly negatively correlated with precipitation, temperature, and humidity (P<0.01), and had the highest correlation coefficients with temperature. (4) Based on the above analysis results, this study analyzed two severe pollution events from late November to early December. Analysis showed that the PM2.5/PM10 ratio in two events remained at about 0.1 when the pollution occurred, but was higher before and after the pollution (up to 1.46). It was shown that the pollution was a simple sandstorm process. Backward trajectory analysis clustered the airflow trajectories reaching Urumqi into 4 categories, and the trajectories from central Asia contributed the maximum values of average PM2.5 and PM10 concentrations.

scholarly journals The spatial and seasonal distributions of air-transport origins to the Antarctic based on 5-day backward trajectory analysis

Polar Science ◽  
2013 ◽  
Vol 7 (3-4) ◽  
pp. 205-213 ◽  
Author(s):  
Kazue Suzuki ◽  
Takashi Yamanouchi ◽  
Kenji Kawamura ◽  
Hideaki Motoyama
Keyword(s):  
Trajectory Analysis ◽  
Air Transport ◽  
Backward Trajectory ◽  
The Antarctic
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