Seasonal and Daily Variations of Ozone, Sulpur Dioxide and Nitrous Gases and the Photochemical Production and Reactions with Other Trace Gases of the Ozone

1987 ◽  
pp. 529-538
Author(s):  
R. Reiter ◽  
R. Sladkivic ◽  
H.-J. Kanter
Keyword(s):  
Trace Gases ◽  
Daily Variations ◽  
Photochemical Production ◽  
Nitrous Gases

scholarly journals A Proof-of-Concept Algorithm for the Retrieval of Total Column Amount of Trace Gases in a Multi-Dimensional Atmosphere

2021 ◽  
Vol 13 (2) ◽  
pp. 270
Author(s):  
Adrian Doicu ◽  
Dmitry S. Efremenko ◽  
Thomas Trautmann
Keyword(s):  
Trace Gases ◽  
Three Dimensional ◽  
Principal Component ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Proof Of Concept ◽  
Discrete Ordinate ◽  
Distribution Method ◽  
Total Column

An algorithm for the retrieval of total column amount of trace gases in a multi-dimensional atmosphere is designed. The algorithm uses (i) certain differential radiance models with internal and external closures as inversion models, (ii) the iteratively regularized Gauss–Newton method as a regularization tool, and (iii) the spherical harmonics discrete ordinate method (SHDOM) as linearized radiative transfer model. For efficiency reasons, SHDOM is equipped with a spectral acceleration approach that combines the correlated k-distribution method with the principal component analysis. The algorithm is used to retrieve the total column amount of nitrogen for two- and three-dimensional cloudy scenes. Although for three-dimensional geometries, the computational time is high, the main concepts of the algorithm are correct and the retrieval results are accurate.

scholarly journals Recommendations for HCHO and SO2 Retrieval Settings from MAX-DOAS Observations under Different Meteorological Conditions

2021 ◽  
Vol 13 (12) ◽  
pp. 2244
Author(s):  
Zeeshan Javed ◽  
Aimon Tanvir ◽  
Muhammad Bilal ◽  
Wenjing Su ◽  
Congzi Xia ◽  
...  
Keyword(s):  
Column Density ◽  
Trace Gases ◽  
Meteorological Conditions ◽  
Optical Absorption Spectroscopy ◽  
Chemical Production ◽  
Vertical Column ◽  
Phase Oxidation ◽  
Fog Days ◽  
Rms Errors ◽  
Optimal Settings

Recently, the occurrence of fog and haze over China has increased. The retrieval of trace gases from the multi-axis differential optical absorption spectroscopy (MAX-DOAS) is challenging under these conditions. In this study, various reported retrieval settings for formaldehyde (HCHO) and sulfur dioxide (SO2) are compared to evaluate the performance of these settings under different meteorological conditions (clear day, haze, and fog). The dataset from 1st December 2019 to 31st March 2020 over Nanjing, China, is used in this study. The results indicated that for HCHO, the optimal settings were in the 324.5–359 nm wavelength window with a polynomial order of five. At these settings, the fitting and root mean squared (RMS) errors for column density were considerably improved for haze and fog conditions, and the differential slant column densities (DSCDs) showed more accurate values compared to the DSCDs between 336.5 and 359 nm. For SO2, the optimal settings for retrieval were found to be at 307–328 nm with a polynomial order of five. Here, root mean square (RMS) and fitting errors were significantly lower under all conditions. The observed HCHO and SO2 vertical column densities were significantly lower on fog days compared to clear days, reflecting a decreased chemical production of HCHO and aqueous phase oxidation of SO2 in fog droplets.

scholarly journals 653 Are Daily Variations in Sleep Quality and Quantity Related to General Stress and COVID-19-Related Anxiety?

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A255-A256
Author(s):  
Veronica Hire ◽  
Casey Thurmon ◽  
Hope Snyder ◽  
Ryan Harra ◽  
Jamie Walker ◽  
...  
Keyword(s):  
Sleep Quality ◽  
Sleep Duration ◽  
Fixed Effects ◽  
Daily Basis ◽  
Subjective Rating ◽  
Coping With Stress ◽  
Sleep Diaries ◽  
Daily Variations ◽  
General Stress ◽  
Stress Levels

Abstract Introduction Sleep modulates a number of psychological and cognitive processes, such as emotion regulation, executive control, and coping with stress. It is therefore not surprising that insufficient sleep quality or quantity are associated with greater self-reported stress levels. The COVID-19 pandemic has led to a particularly stressful and unprecedented time in history. While stress has been undoubtedly high during the past year, it’s less clear to what extent sleep has affected people’s perceived stress on a daily basis. The aim of this research was to estimate whether daily variations in sleep quality and duration were associated with general stress and/or stress related to COVID-19. Methods The study used a nationally representative sample to assess daily variations in sleep and stress for a period of two weeks during the COVID-19 pandemic. Morning assessments were conducted using online sleep diaries. These diaries were used to estimate sleep duration (in minutes) and sleep quality (subjective rating on a 5-point Likert scale). Evening assessments were also completed online and prompted participants to rate (0 to 100) their current “general” stress level, as well as their current anxiety in relation to COVID-19. Separate mixed effects models were conducted with days (Level 1) nested within participants (Level 2). Stress variables were lagged by a day to estimate the association between sleep (AM assessment) and stress (PM assessment). TST and SQ were entered as fixed effects and intercepts were allowed to vary randomly. Results 4,048 participants (Mage = 46.3 years; 78% women) were included as part of the analyses. The results supported that lower self-reported sleep quality predicted greater general stress levels (b = -1.43, p < 0.001). Lower self-reported sleep quality also predicted greater COVID-19 related anxiety (b = -0.543, p < 0.001). In contrast, sleep duration was not significantly related to general stress or COVID-19 anxiety after controlling for sleep quality. Conclusion The present data supports that daily variations in sleep quality are related to a person’s overall stress levels and COVID-19 anxiety. These findings may have implications for the role of good sleep in mitigating the increases in stress that have resulted from the COVID-19 pandemic. Support (if any) Vargas: K23HL141581

scholarly journals Total Ozone Columns from the Environmental Trace Gases Monitoring Instrument (EMI) Using the DOAS Method

2021 ◽  
Vol 13 (11) ◽  
pp. 2098
Author(s):  
Yuanyuan Qian ◽  
Yuhan Luo ◽  
Fuqi Si ◽  
Haijin Zhou ◽  
Taiping Yang ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Total Ozone ◽  
Scattered Light ◽  
Trace Gases ◽  
Rapid Change ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Monitoring Instrument ◽  
Monthly Average

Global measurements of total ozone are necessary to evaluate ozone hole recovery above Antarctica. The Environmental Trace Gases Monitoring Instrument (EMI) onboard GaoFen 5, launched in May 2018, was developed to measure and monitor the global total ozone column (TOC) and distributions of other trace gases. In this study, some of the first global TOC results of the EMI using the differential optical absorption spectroscopy (DOAS) method and validation with ground-based TOC measurements and data derived from Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI) observations are presented. Results show that monthly average EMI TOC data had a similar spatial distribution and a high correlation coefficient (R ≥ 0.99) with both OMI and TROPOMI TOC. Comparisons with ground-based measurements from the World Ozone and Ultraviolet Radiation Data Centre also revealed strong correlations (R > 0.9). Continuous zenith sky measurements from zenith scattered light differential optical absorption spectroscopy instruments in Antarctica were also used for validation (R = 0.9). The EMI-derived observations were able to account for the rapid change in TOC associated with the sudden stratospheric warming event in October 2019; monthly average TOC in October 2019 was 45% higher compared to October 2018. These results indicate that EMI TOC derived using the DOAS method is reliable and has the potential to be used for global TOC monitoring.

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