Method of double averaging for optimum accounting of non-certainty of results of measurements greenhouse gases low gases concentrations at the ground distributed systems of atmospheric measurements

Metrologiya ◽  
2020 ◽  
pp. 19-30 ◽  
Author(s):  
Natig H. Djavadov ◽  
Hikmat H. Asadov ◽  
Reyhana V. Kazimli
Keyword(s):  
Greenhouse Gases ◽  
Metrological Support ◽  
Atmospheric Aerosol ◽  
Suggested Method ◽  
Weighted Averaging ◽  
Cost Functions ◽  
Atmospheric Measurements ◽  
Function Solution ◽  
Optimization Task ◽  
Double Averaging

To increase effectiveness of measurements of concentration of greenhouse gases questions on optimum accounting of non-certainty of results of measurements of low gases concentrations at the ground distributed nets of atmospheric measurements are considered. It is noted that temporal and structural non-stability of atmospheric aerosol leads to occurrence of non-certainty of carried out measurements. It is suggested to use the method of non-conditional variation optimization to determine the optimum interrelation between cost functions of researched atmospheric gas and aerosol which provides best metrological support for carried out measurements. In order to form the functional of optimization the newly suggested method of double averaging is used. The matter of suggested method of double averaging is that two following different averaging operations should be carried out sequentially: geometrical weighted averaging and algebraic averaging. To form the target functional of optimization the limitation condition should be adopted which is imposed to searched for optimum function. Solution of the formulated optimization task of non-conditional variation optimization does show that upon presence of linear interrelation between scalar cost functions of gas and aerosol the target functional could reach its maximum that is the uttermost value of non-certainty of measurements results are reached. On the base of aforesaid the heuristically recommendations on necessity to form the inverse interrelation between scalar values of cost functions of researched gas and atmospheric aerosol are formulated.

scholarly journals The effect of physical and chemical aerosol properties on warm cloud droplet activation

2005 ◽  
Vol 5 (5) ◽  
pp. 8507-8646 ◽  
Author(s):  
G. McFiggans ◽  
P. Artaxo ◽  
U. Baltensperger ◽  
H. Coe ◽  
M. C. Facchini ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Radiative Forcing ◽  
Cloud Droplet ◽  
Size Composition ◽  
Radiative Properties ◽  
Atmospheric Measurements ◽  
Derived Properties ◽  
Aerosol Effects ◽  
Physical And Chemical ◽  
Aerosol Properties

Abstract. The effects of atmospheric aerosol on climate forcing may be very substantial but are quantified poorly at present; in particular, the effects of aerosols on cloud radiative properties, or the "indirect effects" are credited with the greatest range of uncertainty amongst the known causes of radiative forcing. This manuscript explores the effects that the composition and properties of atmospheric aerosol can have on the activation of droplets in warm clouds, so potentially influencing the magnitude of the indirect effect. The effects of size, composition, mixing state and various derived properties are assessed and a range of these properties provided by atmospheric measurements in a variety of locations is briefly reviewed. The suitability of a range of process-level descriptions to capture these aerosol effects is investigated by assessment of their sensitivities to uncertainties in aerosol properties and by their performance in closure studies. The treatment of these effects within global models is reviewed and suggestions for future investigations are made.

Single Instrument Solution for Air Quality and Greenhouse Gas Monitoring in Cities

2020 ◽  
Author(s):  
Morten Hundt ◽  
Oleg Aseev ◽  
Herbert Looser
Keyword(s):  
Air Quality ◽  
Greenhouse Gases ◽  
Environmental Monitoring ◽  
Greenhouse Gas ◽  
Quantum Cascade Lasers ◽  
Atmospheric Measurements ◽  
Gas Monitoring ◽  
Spatial And Temporal Scales ◽  
Laser Absorption ◽  
Single Instrument

<p>Observation of air pollutants and greenhouse gases with high selectivity and sensitivity is of great importance for our understanding of their sources and sinks. For air pollution modelling and validation of emission inventories measurements at various spatial and temporal scales are required. Infrared laser absorption spectroscopy is often the method of choice, offering outstanding performance and reliability. Most frequently, however, this technology is used in a “one-species-one-instrument” solution because of the narrow spectral coverage of DFB-lasers. This can be overcome by combining several Quantum Cascade Lasers (QCLs), providing unique solutions in compact laser absorption spectrometers for environmental monitoring of multiple species in a single instrument.</p><p>We combined multiple DFB-QCLs into a single, compact laser absorption spectrometer to measure up to ten different compounds. We present simultaneous atmospheric measurements of the greenhouse gases CO<sub>2</sub>, N<sub>2</sub>O, H<sub>2</sub>O and CH<sub>4</sub>, and the pollutants CO, NO, NO<sub>2</sub>, O<sub>3</sub>, SO<sub>2</sub> and NH<sub>3</sub> with a single instrument. Furthermore, the instrument performance, first field results and comparison to standard air-quality and greenhouse gas monitoring instrumentation are discussed. The results demonstrate that spectrometers using QCLs can serve as an all-in-one solution for environmental monitoring stations replacing up to seven instruments at once. Furthermore, due to their reduced size and robustness, they can be used on mobile platforms, opening up new applications of air quality and greenhouse gas monitoring in cities.</p>

scholarly journals Particle mobility size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

2010 ◽  
Vol 3 (6) ◽  
pp. 5521-5587 ◽  
Author(s):  
A. Wiedensohler ◽  
W. Birmili ◽  
A. Nowak ◽  
A. Sonntag ◽  
K. Weinhold ◽  
...  
Keyword(s):  
Data Structure ◽  
Size Distribution ◽  
Atmospheric Aerosol ◽  
Size Distributions ◽  
Atmospheric Measurements ◽  
Differential Mobility ◽  
Technical Standards ◽  
Raw Data ◽  
Particle Mobility

Abstract. Particle mobility size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide application in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. This article results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research). Under controlled laboratory conditions, the number size distribution from 20 to 200 nm determined by mobility size spectrometers of different design are within an uncertainty range of ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. Instruments with identical design agreed within ±3% in the peak number concentration when all settings were done carefully. Technical standards were developed for a minimum requirement of mobility size spectrometry for atmospheric aerosol measurements. Technical recommendations are given for atmospheric measurements including continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyser. In cooperation with EMEP (European Monitoring and Evaluation Program), a new uniform data structure was introduced for saving and disseminating the data within EMEP. This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.

scholarly journals The global SF<sub>6</sub> source inferred from long-term high precision atmospheric measurements and its comparison with emission inventories

2010 ◽  
Vol 10 (6) ◽  
pp. 2655-2662 ◽  
Author(s):  
I. Levin ◽  
T. Naegler ◽  
R. Heinz ◽  
D. Osusko ◽  
E. Cuevas ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
High Precision ◽  
Atmospheric Measurements ◽  
Data Set ◽  
Atmospheric Lifetime ◽  
Greenhouse Gases Emissions ◽  
Industrialised Countries ◽  
Global Emissions ◽  
Globally Distributed

Abstract. Emissions of sulphur hexafluoride (SF6), one of the strongest greenhouse gases on a per molecule basis, are targeted to be collectively reduced under the Kyoto Protocol. Because of its long atmospheric lifetime (estimated as 800 to 3200 years), the accumulation of SF6 in the atmosphere is a direct measure of its global emissions. Examination of our extended data set of globally distributed high-precision SF6 observations shows an increase in SF6 abundance from near zero in the 1970s to a global mean of 6.7 ppt by the end of 2008. In-depth evaluation of our long-term data records shows that the global source of SF6 decreased after 1995, most likely due to SF6 emission reductions in industrialised countries, but increased again after 1998. By subtracting those emissions reported by Annex I countries to the United Nations Framework Convention of Climatic Change (UNFCCC) from our observation-inferred SF6 source leaves a surprisingly large gap of more than 70–80% of non-reported SF6 emissions in the last decade. This suggests a strong under-estimation of emissions in Annex I countries and underlines the urgent need for independent atmospheric verification of greenhouse gases emissions accounting.

European Emissions of Halogenated Greenhouse Gases Inferred from Atmospheric Measurements

2011 ◽  
Vol 46 (1) ◽  
pp. 217-225 ◽  
Author(s):  
Christoph A. Keller ◽  
Matthias Hill ◽  
Martin K. Vollmer ◽  
Stephan Henne ◽  
Dominik Brunner ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Atmospheric Measurements

Swiss Emissions of Halogenated Greenhouse Gases derived from Atmospheric Measurements at Beromünster

2021 ◽  
Author(s):  
Dominique Rust ◽  
Martin K. Vollmer ◽  
Ioannis Katharopoulos ◽  
Stephan Henne ◽  
Matthias Hill ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Radiative Forcing ◽  
Anthropogenic Activities ◽  
Stratospheric Ozone ◽  
Regional Scale ◽  
Ratio Method ◽  
Atmospheric Measurements ◽  
Top Down ◽  
Wide Range ◽  
One Year

&lt;p&gt;Synthetic halocarbons reach the atmosphere due to a wide range of anthropogenic activities. They are, for example, used as propellants in foam blowing or as cooling agents in refrigeration and air conditioning. Long-lived halocarbons act as strong greenhouse gases. They are responsible for about 11% of the radiative forcing by long-lived greenhouse gases (LLGHGs). In addition, chlorinated or brominated halocarbons contribute to stratospheric ozone depletion. There are only two in situ long-term measurement programs, operated by the Advanced Global Atmospheric Gases Experiment (AGAGE) and the National Oceanic and Atmospheric Administration (NOAA) that monitor the worldwide abundance of halocarbons in the atmosphere. Based on these observations, halocarbon emissions are estimated by top-down box- or inverse modelling approaches on a global to transnational scale. However, to capture regional pollution sources and to validate country-specific bottom-up emission estimates by top-down methods, additional regional-scale measurements are required.&lt;/p&gt;&lt;p&gt;We present the first continuous halocarbon measurements at the Berom&amp;#252;nster tall tower, representing the most industrialized and densely populated area of Switzerland, the Swiss Plateau. During one year, high precision, high accuracy atmospheric measurements were performed with the analytical setup of the global AGAGE network. This involves sample pre-concentration at low temperatures (down to -180&amp;#160;&lt;sup&gt;o&lt;/sup&gt;C), and analyte separation and detection by gas chromatography and quadrupole mass spectrometry. All halocarbon compound classes of the Montreal and Kyoto Protocols are covered by our measurements. This includes the banned chlorofluorocarbons (CFCs) and halons, the regulated hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), as well as the recently introduced unregulated hydrochfluoroolefins (HFOs). The results improve our understanding of important source areas in Switzerland, and, for the first time offer the possibility to robustly quantify Swiss national halocarbon emissions with observation-based top-down methods, i.e. the tracer ratio method and Bayesian inverse modeling.&lt;/p&gt;

scholarly journals Optimal use of buffer volumes for the measurement of atmospheric gas concentration in multi-point systems

2016 ◽  
Author(s):  
Alessandro Cescatti ◽  
Barbara Marcolla ◽  
Ignacio Goded ◽  
Carsten Gruening
Keyword(s):  
Empirical Relationship ◽  
Concentration Field ◽  
Co2 Concentration ◽  
Surface Fluxes ◽  
Weighted Averaging ◽  
Atmospheric Measurements ◽  
Sampling System ◽  
Temporal Sampling ◽  
Technical Specifications ◽  
Volume Size

Abstract. Accurate multi-point monitoring systems are required to derive atmospheric measurements of greenhouse gas concentrations both for the calculation of surface fluxes with inversion transport models and for the estimation of non-turbulent components of the mass balance equation (i.e. advection and storage fluxes) at eddy covariance sites. When a single analyser is used to monitor multiple sampling points, the deployment of buffer volumes (BV) along sampling lines can reduce the uncertainty due to the discrete temporal sampling of the signal. In order to optimize the use of buffer volumes we explored various setups by simulating their effect on time series of high-frequency CO2 concentration collected at three Fluxnet sites. Besides, we proposed a novel scheme to calculate half hourly weighted averages from discrete point samples, accounting for the probabilistic fraction of the signal generated in the averaging period. Results show that the use of BV with the new averaging scheme reduces the mean absolute errors (MAE) up to 80 % compared to set-up without BV and up to 60 % compared to the case with BV and a standard, non-weighted averaging scheme. The MAE of CO2 concentration measurements was observed to depend on the variability of the concentration field and on the size of BV, which therefore have to be carefully dimensioned. The optimal volume size depends on two main features of the instrumental setup: the number of measurement points and the time needed to sample at one point (i.e. line purging plus sampling time). A linear and consistent relationship was observed at all sites between the sampling frequency, which summarizes the two features mentioned above, and the renewal frequency associated to the volume. Ultimately, this empirical relationship can be applied to estimate the optimal volume size according to the technical specifications of the sampling system.

scholarly journals The evolution of AMULSE (Atmospheric Measurements by Ultra-Light Spectrometer) and its interest in atmospheric applications. Results of the Atmospheric Profiles Of GreenhousE gasEs (APOGEE) weather balloon release campaign for satellite retrieval validation

2019 ◽  
Author(s):  
Lilian Joly ◽  
Olivier Coopmann ◽  
Vincent Guidard ◽  
Thomas Decarpenterie ◽  
Nicolas Dumelié ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Sampling Rate ◽  
Satellite Observations ◽  
Observation System ◽  
Transfer Model ◽  
Atmospheric Measurements ◽  
Infrared Spectral ◽  
Chemical Profiles

Abstract. We report in this paper the development of an embedded ultralight spectrometer (< 3 kg) based on tuneable diode laser absorption spectroscopy (with a sampling rate of 24 Hz) in the mid-infrared spectral region. This instrument is dedicated to in-situ measurements of the vertical profile concentrations of three main greenhouse gases: carbon dioxide (CO2), methane (CH4) and water vapour (H2O) under weather and tethered balloons. The plug and play instrument is compact, robust and cost-effective, autonomous, having a low power consumption, a non-intrusive probe. It was first calibrated during an in situ campaign on an ICOS (Integrated Carbon Observation System) site for several days, then used in a tethered balloon campaign and for a balloon campaign several balloon flights up to 30 km altitude in the Reims-France in 2017–2018 in collaboration with Météo-France/CNRM. This paper shows the valuable interest of the data measured by AMULSE instrument during the APOGEE measurement campaign, specifically for the vertical profiles of CO2 and CH4, which remain very sparse. We have carried out several experiments showing that the measured profiles have several applications: for the validation of simulations of infrared satellite observations, for evaluating the quality of chemical profiles from Chemistry Transport Models (CTM) and for evaluating the quality of retrieved chemical profiles from the assimilation of infrared satellite observations. The results show that the simulations of infrared satellite observations from IASI and CrIS instruments performed in operational mode for NWP by the Radiative Transfer Model (RTM) RTTOV are of good quality. We also show that the MOCAGE and CAMS CTMs modeled ozone profiles fairly accurately and that the CAMS CTM represents the methane in the troposphere well compared to MOCAGE. Finally, the measured in situ ozone profiles allowed us to show the good quality of the retrieved ozone profiles by assimilating ozone-sensitive infrared spectral radiances from IASI and CrIS.

scholarly journals Optimal use of buffer volumes for the measurement of atmospheric gas concentration in multi-point systems

2016 ◽  
Vol 9 (9) ◽  
pp. 4665-4672 ◽  
Author(s):  
Alessandro Cescatti ◽  
Barbara Marcolla ◽  
Ignacio Goded ◽  
Carsten Gruening
Keyword(s):  
Empirical Relationship ◽  
Concentration Field ◽  
Co2 Concentration ◽  
Surface Fluxes ◽  
Weighted Averaging ◽  
Atmospheric Measurements ◽  
Temporal Sampling ◽  
Technical Specifications ◽  
Set Up ◽  
Volume Size

Abstract. Accurate multi-point monitoring systems are required to derive atmospheric measurements of greenhouse gas concentrations both for the calculation of surface fluxes with inversion transport models and for the estimation of non-turbulent components of the mass balance equation (i.e. advection and storage fluxes) at eddy covariance sites. When a single analyser is used to monitor multiple sampling points, the deployment of buffer volumes (BVs) along sampling lines can reduce the uncertainty due to the discrete temporal sampling of the signal. In order to optimize the use of buffer volumes we explored various set-ups by simulating their effect on time series of high-frequency CO2 concentration collected at three Fluxnet sites. Besides, we proposed a novel scheme to calculate half-hourly weighted arithmetic means from discrete point samples, accounting for the probabilistic fraction of the signal generated in the averaging period. Results show that the use of BVs with the new averaging scheme reduces the mean absolute error (MAE) up to 80 % compared to a set-up without BVs and up to 60 % compared to the case with BVs and a standard, non-weighted averaging scheme. The MAE of CO2 concentration measurements was observed to depend on the variability of the concentration field and on the size of BVs, which therefore have to be carefully dimensioned. The optimal volume size depends on two main features of the instrumental set-up: the number of measurement points and the time needed to sample at one point (i.e. line purging plus sampling time). A linear and consistent relationship was observed at all sites between the sampling frequency, which summarizes the two features mentioned above, and the renewal frequency associated with the volume. Ultimately, this empirical relationship can be applied to estimate the optimal volume size according to the technical specifications of the sampling system.

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