Compensation concentration as critical variable for regulating the flux of trace gases between soil and atmosphere

1994 ◽  
Vol 27 (3) ◽  
Author(s):  
Ralf Conrad
Keyword(s):  
Trace Gases ◽  
Critical Variable ◽  
Compensation Concentration

Soil microbial processes and the cycling of atmospheric trace gases

1995 ◽  
Vol 351 (1696) ◽  
pp. 219-230 ◽  
Keyword(s):  
Soil Microorganisms ◽  
Trace Gases ◽  
Microbial Processes ◽  
Trace Gas ◽  
Atmospheric Trace Gases ◽  
Soil Microbial ◽  
Production And Consumption ◽  
Net Flux ◽  
Compensation Concentration ◽  
Carbonyl Sulphide

Soil microbial processes involved in the flux between soil and atmosphere of the atmospheric trace gases methane (CH 4 ), hydrogen (H 2 ), carbon monoxide (CO), carbonyl sulphide (OCS), nitrous oxide (N 2 O ), and nitric oxide (NO) are reviewed. The flux of a trace gas between soil and atmosphere is usually the result of simultaneous production and consumption reactions, so that a compensation concentration exists, at which the net flux is zero. With some of the trace gases, different suites of processes operate at different gas concentrations, so that the processes that consume a trace gas that is produced within the soil are often different from those that consume the trace gas entering the soil from the atmosphere. Certain groups of soil microorganisms can metabolize more than one of these trace gases. The processes involved in the cycling of a trace gas in anoxic wetland soils are often different from those operating in upland soils.

Asset Location: Case Study of a Critical Variable

2001 ◽  
Vol 2001 (4) ◽  
pp. 18-29
Author(s):  
Jean L.P. Brunel
Keyword(s):  
Critical Variable ◽  
Asset Location

Effects of Solar Heating by Aerosols and Trace Gases on the Temperature Structure Constant

1990 ◽  
Author(s):  
J. R. Hummel ◽  
E. P. Shettle
Keyword(s):  
Trace Gases ◽  
Structure Constant ◽  
Solar Heating ◽  
Temperature Structure

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 Young Consumers’ Intention to Participate in the Sharing Economy: An Integrated Model

2021 ◽  
Vol 13 (1) ◽  
pp. 430
Author(s):  
José Alberto Martínez-González ◽  
Eduardo Parra-López ◽  
Almudena Barrientos-Báez
Keyword(s):  
Social Norm ◽  
Structural Model ◽  
Causal Model ◽  
Sharing Economy ◽  
Internal Variables ◽  
Critical Variable ◽  
Generation Z ◽  
External Variables ◽  
Young Consumers ◽  
Intention To Participate

This paper aims to analyze the external and internal drivers of young consumers’ intention to participate in the sharing economy in tourism. From previous findings, a causal model (PLS) is designed to generate an integrated, practical, and novel structural model that significantly predicts the intention to participate. The model, consisting of nine dimensions, includes consumers’ external and internal variables. Separately, these variables have all been considered relevant in the literature, though they have not been studied jointly before. The descriptive results show the excellent attitude and predisposition of young people toward the tourism sharing economy, which facilitates their participation. Through the model, the importance of all internal and external consumer variables in the formation of intention are proven; however, attitude and social norm are most notable among them. Trust is also a critical variable that serves as the link between internal and external variables. The study provides managers of sharing economy platforms with knowledge to encourage young consumers’ participation in a communication and market orientation context. The generational approach (Generation Z) used also allows the conclusions and implications to be transferred to other regions and sectors.

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.

Evaluation of Trinder's Glucose Oxidase Method for Measuring Glucose in Serum and Urine

1975 ◽  
Vol 21 (12) ◽  
pp. 1754-1760 ◽  
Author(s):  
John A Lott ◽  
Kathie Turner
Keyword(s):  
Glucose Oxidase ◽  
Oxidase Activity ◽  
Color Reaction ◽  
Critical Variable ◽  
Wide Range ◽  
Serum And Urine ◽  
Good Agreement

Abstract Trinder's method for glucose has nearly all the attributes of an ideal automated colorimetric glucose oxidase procedure. The chemicals used in the color reaction with peroxidase are readily available, the solutions are stable and can be prepared by the user, the method is highly specific and largely free of interferences, the sensitivity can be adjusted by the user to cover a wide range of glucose concentrations, and the reagents are not hazardous. We found very good agreement between results by this method and by the hexokinase and Beckman Glucose Analyzer methods. The method has been modified and adapted to the AutoAnalyzer I and SMA 6/60 (Technicon) with manifolds that give very little interaction between specimens. A study of the method by the simplex technique revealed that the glucose oxidase activity in the reagent is the most critical variable.

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