scholarly journals Methane emissions from dairies in the Los Angeles Basin

2017 ◽  
Vol 17 (12) ◽  
pp. 7509-7528 ◽  
Author(s):  
Camille Viatte ◽  
Thomas Lauvaux ◽  
Jacob K. Hedelius ◽  
Harrison Parker ◽  
Jia Chen ◽  
...  
Keyword(s):  
Los Angeles ◽  
Near Infrared ◽  
Atmospheric Transport ◽  
Infrared Region ◽  
Top Down ◽  
Ch4 Emissions ◽  
Eddy Simulation ◽  
Wide Range ◽  
The Fourier Transform ◽  
Southern California Region

Abstract. We estimate the amount of methane (CH4) emitted by the largest dairies in the southern California region by combining measurements from four mobile solar-viewing ground-based spectrometers (EM27/SUN), in situ isotopic 13∕12CH4 measurements from a CRDS analyzer (Picarro), and a high-resolution atmospheric transport simulation with a Weather Research and Forecasting model in large-eddy simulation mode (WRF-LES). The remote sensing spectrometers measure the total column-averaged dry-air mole fractions of CH4 and CO2 (XCH4 and XCO2) in the near infrared region, providing information on total emissions of the dairies at Chino. Differences measured between the four EM27/SUN ranged from 0.2 to 22 ppb (part per billion) and from 0.7 to 3 ppm (part per million) for XCH4 and XCO2, respectively. To assess the fluxes of the dairies, these differential measurements are used in conjunction with the local atmospheric dynamics from wind measurements at two local airports and from the WRF-LES simulations at 111 m resolution. Our top-down CH4 emissions derived using the Fourier transform spectrometers (FTS) observations of 1.4 to 4.8 ppt s−1 are in the low end of previous top-down estimates, consistent with reductions of the dairy farms and urbanization in the domain. However, the wide range of inferred fluxes points to the challenges posed by the heterogeneity of the sources and meteorology. Inverse modeling from WRF-LES is utilized to resolve the spatial distribution of CH4 emissions in the domain. Both the model and the measurements indicate heterogeneous emissions, with contributions from anthropogenic and biogenic sources at Chino. A Bayesian inversion and a Monte Carlo approach are used to provide the CH4 emissions of 2.2 to 3.5 ppt s−1 at Chino.

scholarly journals Methane emissions from dairies in the Los Angeles Basin

2016 ◽  
Author(s):  
Camille Viatte ◽  
Thomas Lauvaux ◽  
Jacob K. Hedelius ◽  
Harrison Parker ◽  
Jia Chen ◽  
...  
Keyword(s):  
Los Angeles ◽  
Near Infrared ◽  
Atmospheric Transport ◽  
Infrared Region ◽  
Top Down ◽  
Ch4 Emissions ◽  
Eddy Simulation ◽  
Wide Range ◽  
Gradient Measurements ◽  
The Fourier Transform

Abstract. We estimate the amount of methane (CH4) emitted by the largest dairies in the southern California region by combining measurements from four mobile solar-viewing ground-based spectrometers (EM27/SUN), in situ isotopic 13/12CH4 measurements from a CRDS analyzer (Picarro), and a high-resolution atmospheric transport simulations with Weather Research and Forecasting model in Large-Eddy Simulation mode (WRF-LES). The remote sensing spectrometers measure the total column-averaged dry-air mole fractions of CH4 and CO2 (XCH4 and XCO2) in the near infrared region, providing information about total emissions of the dairies at Chino. Gradients measured by the four EM27/SUN ranged from 0.2 to 22 ppb and from 0.7 to 3 ppm for XCH4 and XCO2, respectively. To assess the fluxes of the dairies, these gradient measurements are used in conjunction with the local atmospheric dynamics from wind measurements at two local airports and from the WRF-LES simulations at 111 m resolution. Our top-down CH4 emissions derived using the Fourier Transform Spectrometers (FTS) observations of 1.4 to 4.8 ppt/s are in the low-end of previous top-down estimates, consistent with reductions of the dairy farms with urbanization in the domain. However, the wide range of inferred fluxes points to the challenges posed by heterogeneity of the sources and meteorology. Inverse modeling from WRF-LES is utilized to resolve the spatial distribution of CH4 emissions in the domain. Both the model and the measurements indicate heterogeneous emissions, with contributions from anthropogenic and biogenic sources at Chino. A Bayesian inversion and a Monte-Carlo approach are used to provide the CH4 emissions of 3.2 to 4.7 ppt/s at Chino.

scholarly journals Abundance and Sources of Atmospheric Halocarbons in the Eastern Mediterranean

2017 ◽  
Author(s):  
Fabian Schoenenberger ◽  
Stephan Henne ◽  
Matthias Hill ◽  
Martin K. Vollmer ◽  
Giorgos Kouvarakis ◽  
...  
Keyword(s):  
Western Europe ◽  
Atmospheric Transport ◽  
Eastern Mediterranean ◽  
Stratospheric Ozone ◽  
Regional Scale ◽  
Top Down ◽  
Inversion Domain ◽  
Hfc 134A ◽  
Wide Range ◽  
Hfc 152A

Abstract. A wide range of anthropogenic halocarbons is released to the atmosphere, contributing to stratospheric ozone depletion and global warming. Using measurements of atmospheric abundances for the estimation of halocarbon emissions on the global and regional scale has become an important top-down tool for emission validation in the recent past, but many populated and developing areas of the world are only poorly covered by the existing atmospheric halocarbon measurement network. Here we present six months of continuous halocarbon observations from Finokalia on the island of Crete in the Eastern Mediterranean. The gases measured are the hydrofluorocarbons (HFCs), HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-152a (CH3CHF2) and HFC-143a (CH3CF3), and the hydrochlorofluorocarbons (HCFCs), HCFC-22 (CHClF2) and HCFC-142b (CH3CClF2). The Eastern Mediterranean is home to 250 million inhabitants, consisting of a number of developed and developing countries, for which different emission regulations exist under the Kyoto and Montreal Protocols. Regional emissions of halocarbons were estimated with Lagrangian atmospheric transport simulations and a Bayesian inverse modelling system, using measurements at Finokalia in conjunction with those from Advanced Global Atmospheric Gases Experiment (AGAGE) sites at Mace Head (Ireland), Jungfraujoch (Switzerland) and Monte Cimone (Italy). Measured peak mole fractions at Finokalia showed generally smaller amplitudes for HFCs than at the European AGAGE sites, except periodic peaks of HFC-152a, indicating strong upwind sources. Higher peak mole fractions were observed for HCFCs, suggesting continued emissions from nearby developing regions such as Egypt and the Middle East. For 2013, the Eastern Mediterranean inverse emission estimates for the four analysed HFCs and the two HCFCs were 14.7 (6.7–23.3) Tg CO2eq yr-1 and 9.7 (4.3–15.7) Tg CO2eq yr-1, respectively. These emissions contributed 17.3 % (7.9–27.4 %) and 53 % (23.5–86%) to the total inversion domain, which covers the Eastern Mediterranean as well as Central and Western Europe. Greek bottom-up HFC emissions reported to the UNFCCC were much smaller than our top-down estimates, whereas for Turkey our estimates agreed with UNFCCC-reported values for HFC-125 and HFC-143a, but were much and slightly smaller for HFC-134a and HFC-152a, respectively. Sensitivity estimates suggest an improvement of the a posteriori emission estimates, i.e. a reduction of the uncertainties by 40–80 %, compared to an inversion using only the existing Central European AGAGE observations.

scholarly journals Influences of hydroxyl radicals (OH) on top-down estimates of the global and regional methane budgets

2020 ◽  
Author(s):  
Yuanhong Zhao ◽  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Xin Lin ◽  
Antoine Berchet ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Climate Models ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Temporal Variations ◽  
Oh Radicals ◽  
Chemical Transport Model ◽  
Top Down ◽  
Ch4 Emissions ◽  
The Impact

Abstract. The hydroxyl radical (OH), which is the dominant sink of methane (CH4), plays a key role to close the global methane budget. Previous research that assessed the impact of OH changes on the CH4 budget mostly relied on box modeling inversions with a very simplified atmospheric transport and no representation of the heterogeneous spatial distribution of OH radicals. Here using a variational Bayesian inversion framework and a 3D chemical transport model, LMDz, combined with 10 different OH fields derived from chemistry-climate models (CCMI experiment), we evaluate the influence of OH burden, spatial distribution, and temporal variations on the global CH4 budget. The global tropospheric mean CH4-reaction-weighted [OH] ([OH]GM-CH4) ranges 10.3–16.3 × 105 molec cm−3 across 10 OH fields during the early 2000s, resulting in inversion-based global CH4 emissions between 518 and 757 Tg yr−1. The uncertainties in CH4 inversions induced by the different OH fields are comparable to, or even larger than the uncertainty typically given by bottom-up and top-down estimates. Based on the LMDz inversions, we estimate that a 1 %-increase in OH burden leads to an increase of 4 Tg yr−1 in the estimate of global methane emissions, which is about 25 % smaller than what is estimated by box-models. The uncertainties in emissions induced by OH are largest over South America, corresponding to large inter-model differences of [OH] in this region. From the early to the late 2000s, the optimized CH4 emissions increased by 21.9 ± 5.7 Tg yr−1 (16.6–30.0 Tg yr−1), of which ~ 25 % (on average) is contributed by −0.5 to +1.8 % increase in OH burden. If the CCMI models represent the OH trend properly over the 2000s, our results show that a higher increasing trend of CH4 emissions is needed to match the CH4 observations compared to the CH4 emission trend derived using constant OH. This study strengthens the importance to reach a better representation of OH burden and of OH spatial and temporal distributions to reduce the uncertainties on the global CH4 budget.

scholarly journals Broadband wavelength demultiplexer using Fano-resonant metasurface

Nanophotonics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1015-1022
Author(s):  
Sang-Eun Mun ◽  
Chulsoo Choi ◽  
Jongwoo Hong ◽  
Byoungho Lee
Keyword(s):  
Optical Sensors ◽  
Fano Resonance ◽  
Near Infrared ◽  
Infrared Region ◽  
Proof Of Concept ◽  
Amplitude Control ◽  
Complete Control ◽  
Wide Range ◽  
Simulation And Experiment ◽  
Design Freedom

AbstractFano resonance, one of the interesting resonance phenomena in physics, provides versatile applications when combined with a concept of metasurface in nanophotonics. Fano-resonant metasurface (FRM) is attracting a lot of attention due to its superior narrowband characteristics as well as design freedom of metasurfaces in nanoscale. However, only the control of apparent asymmetric spectral nature of Fano resonance has been focused at applications such as optical sensors, as the amplitude feature of Fano resonances is relatively easy to control and can be measured by an experimental setup. Here, a method for modulating the phase information of FRM by both simulation and experiment is demonstrated. As a proof of concept, an optical demultiplexer, which can divide four target wavelengths in different directions of free space, is verified experimentally. It covers a broadband wavelength range of more than 350 nm in the near-infrared region with extremely small full-width at half-maximum. This approach can offer the complete control of FRM for a wide range of applications, including optical multiplexers, routers, filters, and switches, beyond conventional applications that have been limited to the amplitude control of Fano resonance.

scholarly journals Wide Range Refractive Index Sensor Using a Birefringent Optical Fiber

2021 ◽  
Author(s):  
Moutusi De ◽  
Vinod Kumar Singh
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
High Sensitivity ◽  
Infrared Region ◽  
Device Fabrication ◽  
Refractive Index Sensor ◽  
Potential Candidate ◽  
Wide Range ◽  
Analyte Detection ◽  
Birefringent Optical Fiber

Abstract In this article, an efficient high birefringent D-shaped photonic crystal fiber (HB-D-PCF) plasmonic refractive index sensor is reported. It is able to work over a long low refractive index (RI) analyte range from 1.29 to 1.36. This modified simple structured hexagonal PCF has high birefringence in the near-infrared region. A thin gold film protected by a titanium dioxide (TiO2) layer is deposited on the D-surface of the PCF which acts as surface plasmon active layer. The sensor consists of an analyte channel on the top of the fiber. The performance of the HB-D-PCF is analyzed based on finite element method (FEM). Both wavelength and amplitude interrogation techniques are applied to study the sensing performance of the optimized sensor. Numerical results show wavelength and amplitude sensitivity of 9245nm/RIU and 1312 RIU-1 respectively with high resolution. Owing to the high sensitivity, long range sensing ability as well as spectral stability the designed HB-D-PCF SPR sensor is a potential candidate for water pollution control, glucose concentration testing, biochemical analyte detection as well as portable device fabrication.

Crystallization and Optical Properties of Sr3Al2O6-SrAl2O4 Eutectic Glass

2018 ◽  
Vol 281 ◽  
pp. 163-168
Author(s):  
Jia Xi Liu ◽  
Nan Lu ◽  
Gang He ◽  
Xiao Yu Li ◽  
Jian Qiang Li ◽  
...  
Keyword(s):  
Near Infrared ◽  
Glass Ceramics ◽  
Photo Luminescence ◽  
Phase Evolution ◽  
Optical Transmittance ◽  
Infrared Region ◽  
Treatment Temperature ◽  
Glass Beads ◽  
Heat Treated ◽  
Wide Range

SrO-Al2O3 ceramics has prospective applications due to its photo-luminescence and persistent afterglow properties. Sr3Al2O6-SrAl2O4 eutectic glass was prepared by using the aerodynamic levitator equipped with a CO2 laser device. The prepared Sr3Al2O6-SrAl2O4 eutectic glass beads were further heat-treated at temperature from 880°C to 980°C. The phase evolution, crystallization behavior, optical transmittance and mechanical properties of the annealed eutectic glass ceramics were investigated. The as-prepared glass is colorless and transparent over a wide range from ultraviolet to near-infrared region, and the average in-line transmittance is over 80% in the range of 260-3200nm. There were two crystal phases Sr3Al2O6 and SrAl2O4 crystallized from the glass beads. With increasing heat-treatment temperature, the transparency of the samples decreased, and the hardness increased. The prepared Sr3Al2O6-SrAl2O4 eutectic glass and glass ceramics may be a promising candidate for the development of photo-luminescence and persistent afterglow materials.

scholarly journals A Straightforward Substitution Strategy to Tune BODIPY Dyes Spanning the Near-Infrared Region via Suzuki–Miyaura Cross-Coupling

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1297 ◽  
Author(s):  
Guanglei Li ◽  
Yu Otsuka ◽  
Takuya Matsumiya ◽  
Toshiyuki Suzuki ◽  
Jianye Li ◽  
...  
Keyword(s):  
Near Infrared ◽  
Cross Coupling ◽  
Cumulus Cells ◽  
Infrared Region ◽  
Quantum Yields ◽  
Nir Dyes ◽  
Wide Range ◽  
One Step ◽  
The One ◽  
First Time

In this study, a series of new red and near-infrared (NIR) dyes derived from 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) were developed by introducing thiophene and its derivatives to the 3- and 5- positions of the dichloroBODIPY core. For the first time, cyclictriol boronates and N-methyliminodiacetic acid (MIDA) boronate were used as organoboron species to couple with 3,5-dichloroBODIPY via the one-step Suzuki–Miyaura cross-coupling. Six kinds of thieno-expended BODIPY dyes were synthesized in acceptable yields ranging from 31% to 79%. All six dyes showed different absorption and emission wavelengths spanning a wide range (c.a. 600–850 nm) in the red and NIR regions with relatively high quantum yields (19–85%). Cellular imaging of 8-(2,6-dimethylphenyl)-re3,5-di(2-thienyl)-BODIPY (dye 1) was conducted using bovine cumulus cells, and the fluorescence microscopy images indicated that the chromophore efficiently accumulated and was exclusively localized in the cytoplasm, suggesting it could be utilized as a subcellular probe. All six dyes were characterized using 1H-NMR and mass spectrometry.

Unlocking the Secrets of Terminalia Kernels Using Near-Infrared Spectroscopy

2021 ◽  
pp. 000370282199213
Author(s):  
Eshetu Bobasa ◽  
Michael Netzel ◽  
Anh Dao Thi Phan ◽  
Heather Smyth ◽  
Yasmina Sultanbawa ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Principal Component ◽  
Near Infrared Reflectance ◽  
Classification Rate ◽  
Potential Health ◽  
Wide Range ◽  
Fruit Samples ◽  
The Fourier Transform ◽  
Kakadu Plum

In recent years, the native food industry in Australia has increased in both value and volume due to the discovery of a wide range of phytochemicals (e.g., vitamin C, polyphenols) that have potential health benefits. Thus, plant organs and tissues of these native plants are used in a wide range of applications. In particular, the kernel of a native plum, the Kakadu plum ( Terminalia ferdinandiana, Combretaceae) is considered to be rich in lipids and other phytochemical compounds. The aim of this study was to evaluate the use of NIR spectroscopy to analyze and characterize kernel samples and tissues of wild harvest fruit samples. The Fourier transform near-infrared reflectance spectra of cracked kernels, seeds cover tissues, and dry powder Kakadu plum kernels were acquired. Both principal component analysis and partial least squares discriminant analysis were used to analyze and interpret the spectral data. A correct classification rate of 93%, 86%, and 80% was achieved for the identification of kernel provenance using all tissues, seed coats, and the whole nuts, respectively. The results of this study reported for the first time the analysis of Kakadu plum kernels and their tissues using NIR spectroscopy.

scholarly journals Monthly trends of methane emissions in Los Angeles from 2011 to 2015 inferred by CLARS-FTS observations

2016 ◽  
Vol 16 (20) ◽  
pp. 13121-13130 ◽  
Author(s):  
Clare K. Wong ◽  
Thomas J. Pongetti ◽  
Tom Oda ◽  
Preeti Rao ◽  
Kevin R. Gurney ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Los Angeles ◽  
Near Infrared ◽  
Late Summer ◽  
Methane Emissions ◽  
Los Angeles Basin ◽  
Top Down ◽  
Time Period ◽  
Infrared Remote Sensing ◽  
Early Fall

Abstract. This paper presents an analysis of methane emissions from the Los Angeles Basin at monthly timescales across a 4-year time period – from September 2011 to August 2015. Using observations acquired by a ground-based near-infrared remote sensing instrument on Mount Wilson, California, combined with atmospheric CH4–CO2 tracer–tracer correlations, we observed −18 to +22 % monthly variability in CH4 : CO2 from the annual mean in the Los Angeles Basin. Top-down estimates of methane emissions for the basin also exhibit significant monthly variability (−19 to +31 % from annual mean and a maximum month-to-month change of 47 %). During this period, methane emissions consistently peaked in the late summer/early fall and winter. The estimated annual methane emissions did not show a statistically significant trend over the 2011 to 2015 time period.

scholarly journals In and Ga Codoped ZnO Film as a Front Electrode for Thin Film Silicon Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Duy Phong Pham ◽  
Huu Truong Nguyen ◽  
Bach Thang Phan ◽  
Thi My Dung Cao ◽  
Van Dung Hoang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Near Infrared ◽  
Infrared Region ◽  
Silicon Solar Cells ◽  
Zno Film ◽  
Thin Film Silicon ◽  
Wide Range ◽  
Transparent Conducting Electrodes

Doped ZnO thin films have attracted much attention in the research community as front-contact transparent conducting electrodes in thin film silicon solar cells. The prerequisite in both low resistivity and high transmittance in visible and near-infrared region for hydrogenated microcrystalline or amorphous/microcrystalline tandem thin film silicon solar cells has promoted further improvements of this material. In this work, we propose the combination of major Ga and minor In impurities codoped in ZnO film (IGZO) to improve the film optoelectronic properties. A wide range of Ga and In contents in sputtering targets was explored to find optimum optical and electrical properties of deposited films. The results show that an appropriate combination of In and Ga atoms in ZnO material, followed by in-air thermal annealing process, can enhance the crystallization, conductivity, and transmittance of IGZO thin films, which can be well used as front-contact electrodes in thin film silicon solar cells.

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