scholarly journals Study of Persistent Pollution in Hefei during Winter Revealed by Ground-Based LiDAR and the CALIPSO Satellite

2021 ◽  
Vol 13 (2) ◽  
pp. 875
Author(s):  
Zhiyuan Fang ◽  
Hao Yang ◽  
Ye Cao ◽  
Kunming Xing ◽  
Dong Liu ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Eastern China ◽  
Northwest China ◽  
Back Trajectory ◽  
Observation Data ◽  
Transport Pathway ◽  
Back Trajectory Analysis ◽  
Maximum Value ◽  
Heavy Pollution ◽  
Ground Based Lidar

LiDAR and CALIPSO satellites are effective tools for detecting air pollution, and by employing PM2.5 observation data, ground-based LiDAR measurements, CALIPSO satellite data, meteorological data, and back-trajectory analysis, we analyzed the process of pollution (moderate pollution, heavy pollution, excellent weather, and dust transmission weather) in Hefei, China from 24 to 27 January 2019 and analyzed the meteorological conditions and pollutants causing heavy pollution. Observation data from the ground station showed that the concentrations of PM10 and PM2.5 increased significantly on 25 January; the maximum value of PM10 was 175 µg/m3, and the maximum value of PM2.5 was 170 µg/m3. In this study, aerosol transboundary transport was observed using a combination of ground-based LiDAR and CALIPSO satellite observations. This method showed that aerosols were distributed at a height of 3–4 km over Hefei at 12:00 on 26 January, and it was found that the aerosols came from the desert region in northwest China. Moreover, we determined its transport pathway based on the backward trajectory, and the transportation of pollutants from the surrounding important industrial cities in central and eastern China led to severe pollution after aggregating and mixing with local aerosols in Hefei in the winter. Therefore, the method proposed in this paper can effectively monitor the optical properties and transportation process of aerosols, help to explore the causes of pollution under complex conditions, and improve environmental quality.

scholarly journals Assessment of meteorology vs. control measures in the China fine particular matter trend from 2013 to 2019 by an environmental meteorology index

2021 ◽  
Vol 21 (4) ◽  
pp. 2999-3013
Author(s):  
Sunling Gong ◽  
Hongli Liu ◽  
Bihui Zhang ◽  
Jianjun He ◽  
Hengde Zhang ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Monitoring Network ◽  
National Average ◽  
Control Measures ◽  
Dominant Factor ◽  
Observation Data ◽  
Heavy Pollution ◽  
Major Factors ◽  
And Control

Abstract. A framework was developed to quantitatively assess the contribution of meteorology variations to the trend of fine particular matter (PM2.5) concentrations and to separate the impacts of meteorology from the control measures in the trend, based upon the Environmental Meteorology Index (EMI). The model-based EMI realistically reflects the role of meteorology in the trend of PM2.5 and is explicitly attributed to three major factors: deposition, vertical accumulation and horizontal transports. Based on the 2013–2019 PM2.5 observation data and re-analysis meteorological data in China, the contributions of meteorology and control measures in nine regions of China were assessed separately by the EMI-based framework. Monitoring network observations show that the PM2.5 concentrations have declined by about 50 % on the national average and by about 35 % to 53 % for various regions. It is found that the nationwide emission control measures were the dominant factor in the declining trend of China PM2.5 concentrations, contributing about 47 % of the PM2.5 decrease from 2013 to 2019 on the national average and 32 % to 52 % for various regions. The meteorology has a variable and sometimes critical contribution to the year-by-year variations of PM2.5 concentrations, 5 % on the annual average and 10 %–20 % for the fall–winter heavy pollution seasons.

scholarly journals Spatiotemporal Variations in Drought and Wetness from 1965 to 2017 in China

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2097
Author(s):  
Zhaoqi Zeng ◽  
Wenxiang Wu ◽  
Yamei Li ◽  
Yang Zhou ◽  
Zhengtao Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Southwest China ◽  
Eastern China ◽  
Northwest China ◽  
Future Climate Change ◽  
Drought Risk ◽  
Severe Drought ◽  
Observation Data ◽  
The Tibetan Plateau ◽  
Extreme Precipitation Events

Drought and extreme precipitation events can have major environmental and socioeconomic impacts. Yet, how drought and wetness are changing in China in the context of climate change is still under debate. Here, the standardized precipitation evapotranspiration index (SPEI) was calculated based on high-quality and more densely distributed daily meteorological observation data from 655 stations across China during the period of 1965–2017. National and regional trends in drought and wetness and their various characteristics, including intensity, duration, frequency, and percentage of area affected, were investigated at multiple timescales. We found that (1) China as a whole has undergone a significant (p < 0.01, trend significant at the level of 0.01) wetting trend, with an annual SPEI increase of 0.5 per decade from 1965 to 2017. A seasonal wetting trend was also observed, with summer being particularly significant (p < 0.01). (2) Regionally, each subregion also showed a wetting trend during the study period except for southwest China, and these wetting trends were significant in the western region of northwest China (p < 0.05, trend significant at the level of 0.05), the Tibetan Plateau (p < 0.05), and eastern China (p = 0.06). (3) Decadal trends in drought and wetness intensity, frequency, duration, and affected areas indicated that the drought events also became more severe and more frequent in the last two decades, and the areas showing drying trends were mainly located in southwest China (especially for the autumn drought) and the southwestern parts of eastern northwest China (spring drought). Our results highlight the fact that although a wetting trend was observed in most regions of China, the frequent occurrence of severe drought in southwest China and the southwestern parts of eastern northwest China still present a considerable threat to both the environment and society. Therefore, how to effectively coordinate the allocation of regional water resources to cope with drought risk under future climate change will be particularly important.

Size-resolved chemical composition of Australian dust aerosol during winter

2011 ◽  
Vol 8 (3) ◽  
pp. 248 ◽  
Author(s):  
M. Radhi ◽  
M. A. Box ◽  
G. P. Box ◽  
M. D. Keywood ◽  
D. D. Cohen ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Mineral Dust ◽  
Ion Beam ◽  
Dust Aerosol ◽  
Back Trajectory ◽  
The South ◽  
Transport Pathway ◽  
Dust Transport ◽  
Back Trajectory Analysis ◽  
Two Samples

Environmental contextMineral dust aerosol is both an efficient scatterer of solar radiation, potentially cooling the planet, and a moderate absorber, potentially warming it: the exact balance is both uncertain, and geographically variable. Australian desert soils are noticeably more reddish than most Northern Hemisphere deserts, most probably a result of enhanced iron mineralogy. This paper contains results from a field campaign designed to increase our understanding of the chemistry of Australian mineral dust aerosol, especially in relation to iron and salt. AbstractAustralia is the dominant source of mineral dust aerosol in the Southern Hemisphere, yet the physical, chemical and optical properties of this aerosol remain poorly understood. Four sets of size-resolved aerosol samples were collected at a site on the edge of the Lake Eyre Basin (LEB), in the south-east dust transport pathway. Back trajectory analysis shows that three samples were sourced from the LEB (one during a rare winter dust storm), and one from coastal regions to the south. All samples were subjected to both ion beam analysis and ion chromatography. A Fe/Al ratio of 0.9 was found, consistent with results from our other campaigns to sites in the LEB, significantly higher than typical Northern Hemisphere values (~0.45–0.6). This confirms the iron-rich character of central Australian soils. Clear evidence of marine advection in the fourth sample was also found, and evidence of chloride depletion by nitric acid in two samples.

scholarly journals Assessment of meteorology vs control measures in China fine particular matter trend from 2013–2019 by an environmental meteorology index

2020 ◽  
Author(s):  
Sunling Gong ◽  
Hongli Liu ◽  
Bihui Zhang ◽  
Jianjun He ◽  
Hengde Zhang ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Monitoring Network ◽  
National Average ◽  
Control Measures ◽  
Dominant Factor ◽  
Observation Data ◽  
Heavy Pollution ◽  
Major Factors ◽  
And Control

Abstract. A framework was developed to quantitatively assess the contribution of meteorology variations in the trend of particular matter (PM) concentrations and to separate the impacts of meteorology from the control measures in the trend, based upon an Environmental Meteorology Index (EMI). The model-based index EMI realistically reflects the role of meteorology in the trend of PM and can also be attributed into three major factors: deposition, vertical accumulation and horizontal transports. Based on the 2013–2019 PM2.5 observation data and re-analysis meteorological data in China, the contributions of meteorology and control measures in nine regions of China were assessed separately by the EMI-based framework. Monitoring network observations show that the PM2.5 concentrations have been declined about 50 % on national average and about 35 % to 53 % for various regions. It is found that the nation-wide emission control measures were the dominant factor in the declining trend of China PM2.5 concentrations, contributing to about 47 % of the PM2.5 decrease from 2013 to 2019 on the national average and 32 % to the 52 % for various regions. The meteorology has a variable and sometimes critical contribution to the year by year variations of PM2.5 concentrations, 5 % on annual average and 10–20 % for the fall-winter heavy pollution seasons.

scholarly journals Ozone seasonal evolution and photochemical production regime in the polluted troposphere in eastern China derived from high-resolution Fourier transform spectrometry (FTS) observations

2018 ◽  
Vol 18 (19) ◽  
pp. 14569-14583 ◽  
Author(s):  
Youwen Sun ◽  
Cheng Liu ◽  
Mathias Palm ◽  
Corinne Vigouroux ◽  
Justus Notholt ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Meteorological Data ◽  
Eastern China ◽  
Back Trajectory ◽  
Seasonal Evolution ◽  
Fourier Transform Spectrometry ◽  
Photochemical Production ◽  
Production Regime ◽  
Tropospheric O3

Abstract. The seasonal evolution of O3 and its photochemical production regime in a polluted region of eastern China between 2014 and 2017 has been investigated using observations. We used tropospheric ozone (O3), carbon monoxide (CO), and formaldehyde (HCHO, a marker of VOCs (volatile organic compounds)) partial columns derived from high-resolution Fourier transform spectrometry (FTS); tropospheric nitrogen dioxide (NO2, a marker of NOx (nitrogen oxides)) partial column deduced from the Ozone Monitoring Instrument (OMI); surface meteorological data; and a back trajectory cluster analysis technique. A broad O3 maximum during both spring and summer (MAM/JJA) is observed; the day-to-day variations in MAM/JJA are generally larger than those in autumn and winter (SON/DJF). Tropospheric O3 columns in June are 1.55×1018 molecules cm−2 (56 DU (Dobson units)), and in December they are 1.05×1018 molecules cm−2 (39 DU). Tropospheric O3 columns in June were ∼50 % higher than those in December. Compared with the SON/DJF season, the observed tropospheric O3 levels in MAM/JJA are more influenced by the transport of air masses from densely populated and industrialized areas, and the high O3 level and variability in MAM/JJA is determined by the photochemical O3 production. The tropospheric-column HCHO∕NO2 ratio is used as a proxy to investigate the photochemical O3 production rate (PO3). The results show that the PO3 is mainly nitrogen oxide (NOx) limited in MAM/JJA, while it is mainly VOC or mixed VOC–NOx limited in SON/DJF. Statistics show that NOx-limited, mixed VOC–NOx-limited, and VOC-limited PO3 accounts for 60.1 %, 28.7 %, and 11 % of days, respectively. Considering most of PO3 is NOx limited or mixed VOC–NOx limited, reductions in NOx would reduce O3 pollution in eastern China.

scholarly journals The Influence of Meteorological Conditions and Atmospheric Circulation Types on PM10 and Visibility in Tel Aviv

2005 ◽  
Vol 44 (5) ◽  
pp. 606-619 ◽  
Author(s):  
Uri Dayan ◽  
Ilan Levy
Keyword(s):  
Particulate Matter ◽  
Extreme Values ◽  
Meteorological Data ◽  
Chemical Properties ◽  
Meteorological Conditions ◽  
Back Trajectory ◽  
Air Masses ◽  
Tel Aviv ◽  
Back Trajectory Analysis ◽  
Synoptic Weather

Abstract A 3-yr dataset (February 2000–November 2002) of 30-min averages for particulates, visibility, and meteorological data were analyzed to examine the dependence of particulate matter of less than 10 μm in diameter (PM10) mass concentrations and visibility in Tel Aviv, Israel, on seasonal meteorological conditions, synoptic weather patterns, and airmass history. The persistent nature of the summer synoptic weather pattern in the east Mediterranean (EM) region yielded the highest mean visibility (35 km) and lowest variability in PM10 concentrations, as compared with the higher variance for the other seasons, and spring in particular. The frequent passage of the “Sharav” cyclones during spring causes natural dust outbreaks with extreme values that result in a much higher PM10 annual mean (57 μg m−3) as compared with other larger cities. The history of the air mass dictating the physical and chemical properties of the particulate matter reaching Israel was assessed by back-trajectory analysis from predetermined transport sectors. The west and central European sectors, representing mostly the summer flow regime of European clean air masses that are advected over the Mediterranean, differ significantly in their reduced PM10 loading and high visual range from the Arabian Peninsula and North African sectors, originating from the surrounding deserts. Because the most frequent direction of air masses reaching the EM is from European origins, Tel Aviv experiences most of the time satisfying visibility conditions. Applying the definition “very good visibility” for visibility exceeding 19 km shows that about 90% of the time these conditions were met for this 3-yr period.

The Analysis of Vegetation Phenology and Climate Change in the North-South Transect of Eastern China

2014 ◽  
Vol 1010-1012 ◽  
pp. 1230-1233 ◽  
Author(s):  
Zhi Wang ◽  
Shi Rong Liu
Keyword(s):  
Climate Change ◽  
Spatial Pattern ◽  
Meteorological Data ◽  
Eastern China ◽  
Terrestrial Ecosystems ◽  
Growing Season ◽  
Distribution Patterns ◽  
Observation Data ◽  
The North ◽  
Temperate Desert

In order to explore additional distribution patterns of global change to terrestrial ecosystems, phenology refers to seasonal biological life stages driven by environmental factors, and is considered to be a sensitive and precise indicator of climate change. Therefore, the author developed a ‘bottom-up’ method for first determining the phenological growing season at sample stations, and based on NOAA/AVVHRR, meteorological data, ground phonology observation data, vegetation category data, and so on. The author built a Logistic fitting model on cumulative frequency of NDVI to determine length of greenness period since 1982, then analyzed correlation between NDVI and precipitation, primarily revealed the dynamic mechanism of climate on vegetation. The spatial pattern of average turning green and wilting dates of the growing season correlated significantly with the spatial pattern of average temperatures in spring and winter across the north south transect of eastern China during 1982 to 2003; the growing season extended on average by 5 to 8 days . Temperate desert regions had the trend of increase of desertification.

scholarly journals Complementary relationship estimation of actual evapotranspiration in extreme cold and arid areas: a case study of the Hotan River Basin, northwest China

2017 ◽  
Vol 49 (5) ◽  
pp. 1540-1558
Author(s):  
Xiaolong Zhang ◽  
Bing Shen ◽  
Lingmei Huang ◽  
Changsen Zhao ◽  
Jiqiang Lyu ◽  
...  
Keyword(s):  
River Basin ◽  
Time Scales ◽  
Meteorological Data ◽  
Remote Sensing Data ◽  
Northwest China ◽  
Actual Evapotranspiration ◽  
Observation Data ◽  
Complementary Relationship ◽  
Mountainous Regions ◽  
Water Surplus

Abstract Application of complementary relationship (CR) approaches using only routine meteorological data is a very convenient method of estimating actual evapotranspiration (ETa). Reanalysis datasets and remote sensing data provide good tools to overcome the difficulties in obtaining observation data. This study of the Hotan River Basin (HRB) in northwest China serves as a prime example for estimation of ETa during 2006–2014 by using the modified generalized CR. Based on comparison and analysis, the maximum potential evaporation calculated by the Penman-based equation was adopted. The estimated ETa rates were verified using a regional water balance method at annual time scales because of the limited available data. The calibration parameter was calibrated based on the elevation and underlying surface types. The mean annual ETa ranged from 2.3 mm to 800 mm during 2006–2014. ETa rates in the plains regions were higher than those in the mountainous regions. Most of ETa was concentrated in the months of May to September. A water deficit occurred in the middle and lower regions, while a water surplus occurred in the upper regions. This study not only provided a new concept for calibration, but also a potential solution for different underlying surfaces and time scales.

scholarly journals Evaluations of Surface PM10 Concentration and Chemical Compositions in MERRA-2 Aerosol Reanalysis over Central and Eastern China

2021 ◽  
Vol 13 (7) ◽  
pp. 1317
Author(s):  
Xiaodan Ma ◽  
Peng Yan ◽  
Tianliang Zhao ◽  
Xiaofang Jia ◽  
Jian Jiao ◽  
...  
Keyword(s):  
Eastern China ◽  
Mainland China ◽  
Chemical Components ◽  
Chemical Compositions ◽  
Observation Data ◽  
Causative Factors ◽  
Routine Sampling ◽  
Aerosol Compositions ◽  
Modern Era

The chemical composition dataset of Aerosol Reanalysis of NASA’s Modern-Era Retrospective Analysis for Research and Application, version 2 (MERRAero) has not been thoroughly evaluated with observation data in mainland China due to the lack of long-term chemical components data. Using the 5-year data of PM10 mass concentrations and chemical compositions obtained from the routine sampling measurements at the World Meteorological Organization the Global Atmosphere Watch Programme regional background stations, Jing Sha (JS) and Lin’An (LA), in central and eastern China, we comprehensively evaluate the surface PM10 concentrations and chemical compositions such as sulfate (SO42−), organic carbon (OC) and black carbon (BC) derived from MERRAero. Overall, the concentrations of PM10, SO42−, OC and BC from the MERRAero agreed well with the measurements, despite a slight and consistent overestimation of BC concentrations and a moderate and persistent underestimation of PM10 concentrations throughout the study period. The MERRAero reanalysis of aerosol compositions performs better during the summertime than wintertime. By considering the nitrate particles in PM10 reconstruction, MERRAero performance can be significantly improved. The unreasonable seasonal variations of PM10 chemical compositions at station LA by MERRAero could be causative factors for the larger MERRAero discrepancies during 2016–2017 than the period of 2011–2013.

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.

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