scholarly journals Supplementary material to "Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns"

2020 ◽  
Author(s):  
Robert D. Field ◽  
Jonathan E. Hickman ◽  
Igor V. Geogdzhayev ◽  
Kostas Tsigaridis ◽  
Susanne E. Bauer
Keyword(s):  
Eastern China ◽  
Atmospheric Composition ◽  
Satellite Retrievals ◽  
Supplementary Material

scholarly journals Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

2021 ◽  
Vol 21 (24) ◽  
pp. 18333-18350
Author(s):  
Robert D. Field ◽  
Jonathan E. Hickman ◽  
Igor V. Geogdzhayev ◽  
Kostas Tsigaridis ◽  
Susanne E. Bauer
Keyword(s):  
Southern China ◽  
Eastern China ◽  
Atmospheric Composition ◽  
Fire Season ◽  
Ozone Monitoring Instrument ◽  
Active Fire ◽  
Background Period ◽  
Satellite Retrievals ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Future Work

Abstract. We examined daily level-3 satellite retrievals of Atmospheric Infrared Sounder (AIRS) CO, Ozone Monitoring Instrument (OMI) SO2 and NO2, and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) over eastern China to understand how COVID-19 lockdowns affected atmospheric composition. Changes in 2020 were strongly dependent on the choice of background period since 2005 and whether trends in atmospheric composition were accounted for. Over central east China during the 23 January–8 April lockdown window, CO in 2020 was between 3 % and 12 % lower than average depending on the background period. The 2020 CO was not consistently less than expected from trends beginning between 2005 and 2016 and ending in 2019 but was 3 %–4 % lower than the background mean during the 2017–2019 period when CO changes had flattened. Similarly for AOD, 2020 was between 14 % and 30 % lower than averages beginning in 2005 and 14 %–17 % lower compared to different background means beginning in 2016. NO2 in 2020 was between 30 % and 43 % lower than the mean over different background periods and between 17 % and 33 % lower than what would be expected for trends beginning later than 2011. Relative to the 2016–2019 period when NO2 had flattened, 2020 was 30 %–33 % lower. Over southern China, 2020 NO2 was between 23 % and 27 % lower than different background means beginning in 2013, the beginning of a period of persistently lower NO2. CO over southern China was significantly higher in 2020 than what would be expected, which we suggest was partly because of an active fire season in neighboring countries. Over central east and southern China, 2020 SO2 was higher than expected, but this depended strongly on how daily regional values were calculated from individual retrievals and reflects background values approaching the retrieval detection limit. Future work over China, or other regions, needs to take into account the sensitivity of differences in 2020 to different background periods and trends in order to separate the effects of COVID-19 on air quality from previously occurring changes or from variability in other sources.

scholarly journals Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

2020 ◽  
Author(s):  
Robert D. Field ◽  
Jonathan E. Hickman ◽  
Igor V. Geogdzhayev ◽  
Kostas Tsigaridis ◽  
Susanne E. Bauer
Keyword(s):  
Southern China ◽  
Eastern China ◽  
Atmospheric Composition ◽  
Fire Season ◽  
Active Fire ◽  
Modis Aod ◽  
Satellite Retrievals ◽  
Level 3 ◽  
Recent Trends ◽  
Future Work

Abstract. We examined daily Level-3 satellite retrievals of AIRS CO, OMI SO2 and NO2, and MODIS AOD over eastern China to understand how COVID-19 lockdowns affected atmospheric composition, taking into account trends that have occurred since 2005. Over central east China during the January 23–April 8 lockdown window, CO in 2020 was 12 % lower than the 2005–2019 mean, but only 2 % lower than what would be expected given the decreasing CO trend over that period. Similarly for AOD, 2020 was 30 % lower than the 2011–2019 mean, but not distinct from what would be expected from the trend. NO2 in 2020 was 43 % lower than the 2011–2019 mean, but only 17 % lower than what would be expected given the trend over that period. Over southern China, 2020 NO2 was not significantly different from anticipated, and CO and AOD were significantly higher that what would be expected, which we suggest was partly because of an active fire season in neighbouring countries. Over east central and southern China, SO2 was higher than expected, but the magnitude depended strongly on how daily regional values were calculated from individual retrievals. Future work over China, or other regions, needs to take these trends into account in order to separate the effects of COVID-19 on air quality from recent trends, or from variability in other sources.

scholarly journals Supplementary material to "Response of atmospheric composition to COVID-19 lockdown measures during Spring in the Paris region (France)"

2021 ◽  
Author(s):  
Jean-Eudes Petit ◽  
Jean-Charles Dupont ◽  
Olivier Favez ◽  
Valérie Gros ◽  
Yunjiang Zhang ◽  
...  
Keyword(s):  
Atmospheric Composition ◽  
Supplementary Material ◽  
Paris Region

An integrated organic–inorganic geochemical characterization of Paleogene sediments in No.1 Structural Belt of the Nanpu Sag, Bohai Bay Basin, eastern China: implications for the origin of organic matter

2020 ◽  
Vol 21 (1) ◽  
pp. geochem2019-060
Author(s):  
Yu Guo ◽  
Wenzhe Gang ◽  
Gang Gao ◽  
Shangru Yang ◽  
Chong Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Higher Plants ◽  
Eastern China ◽  
Source Rocks ◽  
Bohai Bay ◽  
Type Ii ◽  
Lacustrine Environment ◽  
Anoxic Conditions ◽  
Supplementary Material ◽  
Nanpu Sag

Paleogene sediments, especially the third member of the Dongying Formation (Ed3) and the first and third members of the Shahejie Formation (Es1 and Es3), have been regarded as the most important source rocks in the Nanpu Sag. Organic and inorganic analyses, including Rock-Eval pyrolysis, gas chromatography-mass spectrometry, and element geochemistry, in 91 mudstone samples, were used to reconstruct the palaeoenvironmental conditions, such as palaeoclimate, palaeo-salinity and palaeo-redox conditions, and to recognize the origin of organic matter. The results show that Es3 has a higher TOC content than Es1 and Ed3. Hydrocarbon genetic potential (S1 + S2) of the samples indicate fair to good hydrocarbon potential. The kerogen type of Ed3 and Es1 source rocks are Type II1–II2, while Es3 source rocks are dominated by Type II2–III kerogens. Biomarkers and inorganic geochemical indicatives of source rocks, such as Pr/Ph, V/(V + Ni) and Cu/Zn, indicate a lacustrine environment with fresh to brackish water under suboxic to anoxic conditions during deposition. Ed3 source rocks are characterized by low G/C30H (gamacerane/C30hopane) (<0.1), TT/C30H (tricyclic terpane/C30hopane) and S/H (serane/hopane), high Pr/Ph (pristane/phytane) and C24TeT/C23TT (C24tetracyclic terpane/C23tricyclic terpane), indicating mixed input of both algae and terrestrial higher plants, dominated by terrestrial higher plants. Es1 source rocks display medium G/C30H, TT/C30H, S/H, Pr/Ph and C24TeT/C23TT, indicative of a mixed input of both algae and terrestrial higher plants. Es3 source rocks are characterized by high G/C30H (>0.1), TT/C30H and S/H, low Pr/Ph and C24TeT/C23TT, typical of a mixed input of algae and terrestrial higher plants, with algal dominance. Ed3, Es1 and Es3 source rocks were mostly deposited in semi-arid to humid-warm climate conditions, with an average temperature higher than 15°C. This study suggests that suitable temperatures, a fresh to brackish lacustrine environment and suboxic to anoxic conditions could result in a high organic matter concentration and preservation, thus providing prerequisites for the formation of high-quality source rocks.Supplementary material: Tables S1–S3 are available at https://doi.org/10.6084/m9.figshare.c.5227684

scholarly journals Fourier transform infrared time series of tropospheric HCN in eastern China: seasonality, interannual variability, and source attribution

2020 ◽  
Vol 20 (9) ◽  
pp. 5437-5456
Author(s):  
Youwen Sun ◽  
Cheng Liu ◽  
Lin Zhang ◽  
Mathias Palm ◽  
Justus Notholt ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Interannual Variability ◽  
Eastern China ◽  
Fourier Transform Infrared ◽  
Atmospheric Composition ◽  
High Spectral Resolution ◽  
Source Attribution ◽  
Solar Absorption ◽  
Back Trajectories ◽  
Mauna Loa

Abstract. We analyzed seasonality and interannual variability of tropospheric hydrogen cyanide (HCN) columns in densely populated eastern China for the first time. The results were derived from solar absorption spectra recorded with a ground-based high-spectral-resolution Fourier transform infrared (FTIR) spectrometer in Hefei (31∘54′ N, 117∘10′ E) between 2015 and 2018. The tropospheric HCN columns over Hefei, China, showed significant seasonal variations with three monthly mean peaks throughout the year. The magnitude of the tropospheric HCN column peaked in May, September, and December. The tropospheric HCN column reached a maximum monthly mean of (9.8±0.78)×1015 molecules cm−2 in May and a minimum monthly mean of (7.16±0.75)×1015 molecules cm−2 in November. In most cases, the tropospheric HCN columns in Hefei (32∘ N) are higher than the FTIR observations in Ny-Ålesund (79∘ N), Kiruna (68∘ N), Bremen (53∘ N), Jungfraujoch (47∘ N), Toronto (44∘ N), Rikubetsu (43∘ N), Izana (28∘ N), Mauna Loa (20∘ N), La Reunion Maido (21∘ S), Lauder (45∘ S), and Arrival Heights (78∘ S) that are affiliated with the Network for Detection of Atmospheric Composition Change (NDACC). Enhancements of tropospheric HCN column were observed between September 2015 and July 2016 compared to the same period of measurements in other years. The magnitude of the enhancement ranges from 5 % to 46 % with an average of 22 %. Enhancement of tropospheric HCN (ΔHCN) is correlated with the concurrent enhancement of tropospheric CO (ΔCO), indicating that enhancements of tropospheric CO and HCN were due to the same sources. The GEOS-Chem tagged CO simulation, the global fire maps, and the potential source contribution function (PSCF) values calculated using back trajectories revealed that the seasonal maxima in May are largely due to the influence of biomass burning in Southeast Asia (SEAS) (41±13.1 %), Europe and boreal Asia (EUBA) (21±9.3 %), and Africa (AF) (22±4.7 %). The seasonal maxima in September are largely due to the influence of biomass burnings in EUBA (38±11.3 %), AF (26±6.7 %), SEAS (14±3.3 %), and North America (NA) (13.8±8.4 %). For the seasonal maxima in December, dominant contributions are from AF (36±7.1 %), EUBA (21±5.2 %), and NA (18.7±5.2 %). The tropospheric HCN enhancement between September 2015 and July 2016 at Hefei (32∘ N) was attributed to an elevated influence of biomass burnings in SEAS, EUBA, and Oceania (OCE) in this period. In particular, an elevated number of fires in OCE in the second half of 2015 dominated the tropospheric HCN enhancement between September and December 2015. An elevated number of fires in SEAS in the first half of 2016 dominated the tropospheric HCN enhancement between January and July 2016.

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