Modeling radiative forcing by background aerosol on the basis of measurement data

2009 ◽  
Vol 45 (4) ◽  
pp. 467-477 ◽  
Author(s):  
I. A. Gorchakova ◽  
T. A. Tarasova ◽  
M. A. Sviridenkov ◽  
P. P. Anikin ◽  
E. V. Romashova
Keyword(s):  
Radiative Forcing ◽  
Measurement Data

scholarly journals Light absorption of brown carbon aerosol in the PRD region of China

2016 ◽  
Vol 16 (3) ◽  
pp. 1433-1443 ◽  
Author(s):  
J.-F. Yuan ◽  
X.-F. Huang ◽  
L.-M. Cao ◽  
J. Cui ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Measurement Data ◽  
Theoretical Assumption ◽  
Ambient Aerosols ◽  
Brown Carbon ◽  
Mass Spectrometers ◽  
Rural Environments ◽  
The Pearl River

Abstract. The strong spectral dependence of light absorption of brown carbon (BrC) aerosol is regarded to influence aerosol's radiative forcing significantly. The Absorption Angstrom Exponent (AAE) method has been widely used in previous studies to attribute light absorption of BrC at shorter wavelengths for ambient aerosols, with a theoretical assumption that the AAE of "pure" black carbon (BC) aerosol equals to 1.0. In this study, the AAE method was applied to both urban and rural environments in the Pearl River Delta (PRD) region of China, with an improvement of constraining the realistic AAE of "pure" BC through statistical analysis of on-line measurement data. A three-wavelength photo-acoustic soot spectrometer (PASS-3) and aerosol mass spectrometers (AMS) were used to explore the relationship between the measured AAE and the relative abundance of organic aerosol to BC. The regression and extrapolation analysis revealed that more realistic AAE values for "pure" BC aerosol (AAEBC) were 0.86, 0.82, and 1.02 between 405 and 781 nm, and 0.70, 0.71, and 0.86 between 532 and 781 nm, in the campaigns of urbanwinter, urbanfall, and ruralfall, respectively. Roadway tunnel experiments were conducted and the results further confirmed the representativeness of the obtained AAEBC values for the urban environment. Finally, the average light absorption contributions of BrC (± relative uncertainties) at 405 nm were quantified to be 11.7 % (±5 %), 6.3 % (±4 %), and 12.1 % (±7 %) in the campaigns of urbanwinter, urbanfall, and ruralfall, respectively, and those at 532 nm were 10.0 % (±2 %), 4.1 % (±3 %), and 5.5 % (±5 %), respectively. The relatively higher BrC absorption contribution at 405 nm in the ruralfall campaign could be reasonably attributed to the biomass burning events nearby, which was then directly supported by the biomass burning simulation experiments performed in this study. This paper indicates that the BrC contribution to total aerosol light absorption at shorter wavelengths is not negligible in the highly urbanized and industrialized PRD region.

scholarly journals Long term trends in aerosol optical characteristics in the Po Valley (IT)

2014 ◽  
Vol 14 (7) ◽  
pp. 9041-9065
Author(s):  
J. P. Putaud ◽  
F. Cavalli ◽  
S. Martins dos Santos ◽  
A. Dell'Acqua
Keyword(s):  
Radiative Forcing ◽  
Mass Concentration ◽  
Measurement Data ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Po Valley ◽  
Aerosol Absorption ◽  
Aerosol Scattering ◽  
The One

Abstract. Aerosols properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra on the edge of the Po Valley for almost one decade. In-situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sunphotometer data are produced by AERONET. Data show significant decreasing trends over 2004–2010 for a number of variables including particulate matter (PM) mass concentration, aerosol scattering, backscattering and absorption coefficients, and aerosol optical thickness (AOT). In-situ measurement data show no significant trend in the aerosol backscatter ratio, but a significant decreasing trend of about −0.7 ± 0.3% in the aerosol single scattering albedo in the visible light range. Similar trends are observed in the aerosol single scattering albedo retrieved from sunphotometer measurements. Correlations appear between in situ PM mass concentration and aerosol scattering coefficient on the one hand, and elemental carbon (EC) and aerosol absorption coefficient on the other hand, however, no increase in the EC / PM ratio was observed, which could have explained the decrease in SSA. The application of a simple approximation to calculate the direct radiative forcing by aerosols suggests a significant diminution in their cooling effect, mainly due to the decrease in AOT. Applying the methodology we present to those sites where the necessary suite of measurements is available would provide important information to inform future policies for air quality enhancement and fast climate change mitigation.

scholarly journals Chemical composition, optical properties and radiative forcing efficiency of nascent particulate matter emitted by an aircraft turbofan burning conventional and alternative fuels

2018 ◽  
Author(s):  
Miriam Elser ◽  
Benjamin T. Brem ◽  
Lukas Durdina ◽  
David Schönenberger ◽  
Frithjof Siegerist ◽  
...  
Keyword(s):  
Optical Properties ◽  
Particulate Matter ◽  
Chemical Composition ◽  
Radiative Forcing ◽  
Alternative Fuels ◽  
Measurement Data ◽  
Particulate Emissions ◽  
Low Thrust ◽  
Fuel Blends ◽  
Wide Range

Abstract. Aircraft engines are a unique source of carbonaceous aerosols in the upper troposphere. There, these particles can more efficiently interact with solar radiation than at ground. Due to the lack of measurement data, the radiative forcing from aircraft particulate emissions remains uncertain. To better estimate the global radiative effects of aircraft exhaust aerosol, its optical properties need to be comprehensively characterized. In this work we present the link between the chemical composition and the optical properties of the particulate matter (PM) measured at the engine exit plane of a CFM56-7B turbofan. The measurements covered a wide range of power settings (thrust), ranging from ground idle to take-off, using four different fuel blends of conventional Jet A-1 and Hydro-processed Ester and Fatty Acids (HEFA) biofuel. At the two measurement wavelengths (532 and 870 nm) and for all tested fuels, the absorption and scattering coefficients increased with thrust, as did the PM mass. The separation of elemental carbon (EC) and organic carbon (OC) revealed a significant mass fraction of OC (up to 90 %) at low thrust levels, while EC mass dominated at medium and high thrust. The use of HEFA blends induced a significant decrease in the PM mass and the optical coefficients at all thrust levels. The HEFA effect was highest at low thrust levels, where the EC mass was reduced by up to 50–60 %. The variability in the chemical composition of the particles was the main reason for the strong thrust dependency of the single scattering albedo (SSA), which followed the same trend as the OC fraction. Mass absorption coefficients (MAC) were determined from the correlations between aerosol light absorption and EC mass concentration. The obtained MAC values (MAC532 = 7.5 ± 0.3 m2 g−1 and MAC870 = 5.2 ± 0.9 m2 g−1) are in excellent agreement with previous literature values of absorption cross section for freshly generated soot. The Simple Forcing Efficiency (SFE) was used to evaluate the direct radiative effect of aircraft particulate emissions for various ground surfaces. The results indicate that aircraft PM emissions over highly reflective surfaces like snow or ice have a substantial warming effect. The use of the HEFA fuel blends decreased PM emissions, but no changes where observed in terms of EC/OC composition, optical properties and forcing per mass emitted.

scholarly journals Reduced ice number concentrations in contrails from low-aromatic biofuel blends

2021 ◽  
Vol 21 (22) ◽  
pp. 16817-16826
Author(s):  
Tiziana Bräuer ◽  
Christiane Voigt ◽  
Daniel Sauer ◽  
Stefan Kaufmann ◽  
Valerian Hahn ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Measurement Data ◽  
Climate Impact ◽  
Aviation Fuel ◽  
Fuel Blend ◽  
Extinction Coefficients ◽  
Flight Experiment ◽  
Maximum Reduction ◽  
Aromatic Content ◽  
Fuel Jet

Abstract. Sustainable aviation fuels can reduce contrail ice numbers and radiative forcing by contrail cirrus. We measured apparent ice emission indices for fuels with varying aromatic content at altitude ranges of 9.1–9.8 and 11.4–11.6 km. Measurement data were collected during the ECLIF II/NDMAX flight experiment in January 2018. The fuels varied in both aromatic quantity and type. Between a sustainable aviation fuel blend and a reference fuel Jet A-1, a maximum reduction in apparent ice emission indices of 40 % was found. We show vertical ice number and extinction distributions for three different fuels and calculate representative contrail optical depths. Optical depths of contrails (0.5–3 min in age) were reduced by 40 % to 52 % for a sustainable aviation fuel compared to the reference fuel. Our measurements suggest that sustainable aviation fuels result in reduced ice particle numbers, extinction coefficients, optical depth and climate impact from contrails.

scholarly journals Long-term trends in aerosol optical characteristics in the Po Valley, Italy

2014 ◽  
Vol 14 (17) ◽  
pp. 9129-9136 ◽  
Author(s):  
J. P. Putaud ◽  
F. Cavalli ◽  
S. Martins dos Santos ◽  
A. Dell'Acqua
Keyword(s):  
Radiative Forcing ◽  
Mass Concentration ◽  
Measurement Data ◽  
Single Scattering ◽  
Po Valley ◽  
Aerosol Absorption ◽  
Aerosol Scattering ◽  
Sun Photometer ◽  
The One

Abstract. Aerosol properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra, on the edge of the Po Valley, for almost one decade. In situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sun-photometer data are produced by the Aerosol Robotic Network (AERONET). Data show significant decreasing trends over the 2004–2010 period for a number of variables, including particulate matter (PM) mass concentration, aerosol scattering, backscattering and absorption coefficients, and aerosol optical thickness (AOT). In situ measurement data show no significant trends in the aerosol backscatter ratio, but they do show a significant decreasing trend of about −0.7 ± 0.3% yr−1 in the aerosol single scattering albedo (SSA) in the visible light range. Similar trends are observed in the SSA retrieved from sun-photometer measurements. Correlations appear between in situ PM mass concentration and aerosol scattering coefficient, on the one hand, and elemental carbon (EC) concentration and aerosol absorption coefficient, on the other hand. However, no increase in the EC / PM ratio was observed, which could have explained the decrease in SSA. The application of a simple approximation to calculate the direct radiative forcing by aerosols suggests a significant diminution in their cooling effect, mainly due to the decrease in AOT. Applying the methodology we present to those sites, where the necessary suite of measurements is available, would provide important information to inform future policies for air-quality enhancement and fast climate change mitigation.

scholarly journals Reduced ice number concentrations in contrails from low aromatic biofuel blends

2021 ◽  
Author(s):  
Tiziana Bräuer ◽  
Christiane Voigt ◽  
Daniel Sauer ◽  
Stefan Kaufmann ◽  
Valerian Hahn ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Measurement Data ◽  
Climate Impact ◽  
Aviation Fuel ◽  
Fuel Blend ◽  
Extinction Coefficients ◽  
Flight Experiment ◽  
Maximum Reduction ◽  
Aromatic Content ◽  
Fuel Jet

Abstract. Sustainable aviation fuels can reduce contrail ice numbers and radiative forcing by contrail cirrus. We measured apparent ice emission indices for fuels with varying aromatic content at altitude ranges of 9.1–9.8 km and 11.4–11.6 km. Measurement data were collected during the ECLIF II/NDMAX flight experiment in January 2018. The fuels varied in both aromatic quantity and type. Between a sustainable aviation fuel blend and a reference fuel Jet A-1, a maximum reduction in apparent ice emission indices of 40 % was found. We show vertical ice number and extinction distributions for three different fuels and calculate representative contrail optical depths. Optical depths of contrails (0.5–3 minutes in age) were reduced by 40 to 52 % for a sustainable aviation fuel compared to the reference fuel. Our measurements suggest that sustainable aviation fuels result in reduced ice particle numbers, extinction coefficients, optical depth and climate impact from contrails.

Metrological support of individual blood glucose meters in telemedicine

2019 ◽  
pp. 52-56
Author(s):  
Yu.F. Glukhov ◽  
N.V. Krutikov ◽  
A.V. Ivanov ◽  
N.P. Muravskaya
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Measurement Data ◽  
Test Method ◽  
Level Measurement ◽  
Measurement Devices ◽  
Real Practice ◽  
Health Care Centers ◽  
Medical Measurement

We have studied and analyzed status and metrological supervision of blood glucose monitors, individual devices for a person’s blood glucose level measurement. It has been indicated that nowadays blood glucose monitors like other individual devices for medical measurement are not allowed to be involved in telemedicine public service. This accounts for absence of metrological supervision with these measurement devices in telemedicine. In addition, the key problem is absence of safe methods and means of remote verificaition, calibration and transmission of measurement data to health care centers. The article offers a remote test method for blood glucose monitors using a number of resistors with values correlating with measured blood glucose level. The available method has been successfully trialed in real practice.

Intelligent building development and LabView-based modelling of a net zero-energy strategy

2014 ◽  
Vol 5 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Cs. Szász
Keyword(s):  
Development Strategy ◽  
Measurement Data ◽  
Renewable Energy Resources ◽  
Balance Performance ◽  
Zero Energy ◽  
Intelligent Building ◽  
Labview Software ◽  
Net Zero Energy ◽  
Net Zero Energy Building ◽  
Net Zero

The paper presents an intelligent building (IB) development strategy emphasizing the locally available non-polluting renewable energy resources utilization. Considering the immense complexity of the topic, the implementation strategy of the main energy-flow processes is unfolded, using the net zero-energy building concept (NZEB). Noticeably, in the first research steps the mathematical background of the considered NZEB strategy has been developed and presented. Then careful LabView software-based simulations prove that the adopted strategy is feasible for implementation. The result of the above mentioned research efforts is a set of powerful and versatile software toolkits well suitable to model and simulate complex heating, ventilation and air-conditioning processes and to perform energy balance performance evaluations. Besides the elaborated mathematical models, concrete software implementation examples and measurement data also is provided in the paper. Finally, the proposed original models offer a feasible solution for future developments and research in NZEB applications modelling and simulation purposes.

Sign in / Sign up

Export Citation Format

Share Document