scholarly journals Review of In-Situ Online LIBS Detection in the Atmospheric Environment

2021 ◽  
Vol 42 (6) ◽  
Author(s):  
Yuzhu Liu
Keyword(s):  
Atmospheric Environment

scholarly journals Comparison of Structure Stability of Graphene and Mxene by Peak Force Tapping Mode of Atomic Force Microscope

2021 ◽  
Author(s):  
Cai Shen
Keyword(s):  
Etching Rate ◽  
Peak Force ◽  
Atmospheric Environment ◽  
Damage Effect ◽  
Structure Stability ◽  
Two Dimensional ◽  
Tapping Mode ◽  
Scanning Time ◽  
The Stability

In this paper, the structural stability of graphene and Mexene was compared by peak force tapping mode of AFM. When in-situ scanning of two-dimensional material of reduced graphene oxide (rGO), the morphology of rGO did not change with time, which indicated that peak force tapping mode had no damage effect on the stable structure surface; while when in-situ scanning of two-dimensional material V2C, nano-etching occurred on the surface of V2C, and the morphology surface area decreased with scanning time. The data processing software was used to analyze the area change and calculate the nano etching rate. It was found that the average nano-etching rate increased with the increase of the peak force, and the etching rate in the atmospheric environment was higher than that in the glove box (Ar atmosphere, the H2O and O2 content was less than 1 ppm), which indicated that the moisture in the atmosphere had an impact on the stability of the material and would accelerate the nano-etching. This study shows that the peak force tapping mode of AFM can be used to qualitatively characterize the stability of two-dimensional materials

scholarly journals In-Situ FTIR Study of Heterogeneous Oxidation of SOA Tracers by Ozone

2021 ◽  
Vol 2 ◽  
Author(s):  
Runhua Wang ◽  
Yajuan Huang ◽  
Qian Hu ◽  
Gang Cao ◽  
Rongshu Zhu
Keyword(s):  
Global Climate ◽  
Reaction Rate Constant ◽  
Ozone Exposure ◽  
Atmospheric Environment ◽  
High Concentration ◽  
Pseudo First Order Reaction ◽  
Heterogeneous Oxidation ◽  
Change Rate ◽  
Absorption Area

Secondary organic aerosols (SOA) play an important role in global climate change and air quality, and SOA tracers can directly characterize the source and reaction mechanism of SOA. However, it is not well known that whether the tracers can be oxidized or how the instability of the tracers in the atmosphere. In this paper, in-situ FTIR was used to analyze the chemical structure changes of erythritol, analogue of 2-methyl erythritol (AME) that is, a tracer of isoprene SOA, and 2, 3-dihydroxy-4-oxopentanoic acid (DHOPA), a tracer of toluene SOA, when exposed to high concentration of ozone for short periods. Under the condition of 20 ppm ozone exposure for 30 min, the change rate of absorption area of AME at 3,480 and 1700 cm−1 was −0.0134 and 0.00117 int.abs/s, respectively, and the change rate of the absorption area of DHOPA at 1,640 and 3340cm−1 was −0.00191 and 0.00218 int.abs/s, respectively. The pseudo-first-order reaction rate constant kapp were 1.89 × 10−8 and 2.12 × 10−7 s−1, and the uptake coefficients of ozone on the surface of AME and DHOPA were (1.3 ± 0.8) × 10−8 and (4.5 ± 2.7) × 10−8, respectively. These results showed the oxidation processes of AME and DHOPA were slow in the presence of high concentrations of ozone, which implied that AME and DHOPA could be considered to be stable in the atmospheric environment with ozone as the main oxidant.

In-situ Observation of Cosmetic Corrosion Behavior under Atmospheric Environment

2021 ◽  
Vol 70 (1) ◽  
pp. 18-27
Author(s):  
Shunsuke Yamamoto ◽  
Satoru Ando
Keyword(s):  
Corrosion Behavior ◽  
Atmospheric Environment ◽  
In Situ Observation

Post-flight analysis of the aerosol impact on size distributions of warm clouds’ droplets, as determined in situ by cloud and aerosol spectrometers

2020 ◽  
Author(s):  
Denisa Elena Moacă ◽  
Sorin Nicolae Vâjâiac ◽  
Andreea Calcan ◽  
Valeriu Filip
Keyword(s):  
Size Distribution ◽  
Pure Water ◽  
Weather Forecast ◽  
Cloud Microphysics ◽  
Atmospheric Environment ◽  
Size Distributions ◽  
Cloud Droplets ◽  
Cloud Particle ◽  
Microphysical Properties

<p>The influence of aerosol on the various aspects of the atmospheric properties as well as on the energetic balance is widely recognised in the scientific community and this issue is currently subject to worldwide intense investigations. Among the multiple ways aerosol particles are impacting the atmospheric environment, their interference with the phase transformations of the atmospheric water is of particular importance. Cloud microphysics, on the other hand, is one of the key components in weather forecast and, therefore, in pursuing daily domestic activities ranging from agriculture to energy harvesting and aviation. The micro-physical processes taking place in clouds are strongly influenced by the spatiotemporal variation of the size distribution of the cloud droplets. In this context, as in situ investigations of clouds seem appropriate, one of the most useful types of instruments is casted into the generic name of Cloud and Aerosol Spectrometer (CAS) that can be mounted on specialized research aircraft. The CAS working principle relies basically on measuring the forward scattering cross section (FWSCS) of light with a certain wavelength on a cloud particle and comparing it to the FWSCS computed for pure water spheres. The eventual matching of these values leads to assigning a certain value for the measured particle’s diameter. The light wavelength is usually chosen in a range where pure water has virtually no absorption. However, atmospheric aerosol frequently mixes up with cloud droplets (starting even from the nucleation processes) and alters their optical properties. By increasing absorption and/or refractivity with respect to those of pure water, one can easily show that the FWSCS-diameter diagram changes drastically by becoming smoother and with an overall significant decrease in absolute values. This means that a CAS will systematically count “contaminated” cloud droplets in a lower range of diameters, thus distorting their real size distribution. This effect is inherently degrading the objectivity of CAS measurements and should be more pronounced when levels of sub-micrometer sized aerosol increase at the cloud altitude. The present study aims at pointing out such correlation in order to estimate the reliability of size distributions (and of the ensuing cloud microphysical properties) obtained by CAS.</p>

In situ observation of superstructures on InP(0 0 1) surface under hydrogen atmospheric environment with using grazing incidence X-ray diffraction

2000 ◽  
Vol 221 (1-4) ◽  
pp. 106-110 ◽  
Author(s):  
T Kawamura ◽  
Y Watanabe ◽  
Y Utsumi ◽  
K Uwai ◽  
J Matsui ◽  
...  
Keyword(s):  
Grazing Incidence ◽  
Atmospheric Environment ◽  
In Situ Observation ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Constraining black carbon aerosol over Southeast Asia using OMI aerosol absorption optical depth and the adjoint of GEOS-Chem

2014 ◽  
Vol 14 (21) ◽  
pp. 28385-28452 ◽  
Author(s):  
L. Zhang ◽  
D. K. Henze ◽  
G. A. Grell ◽  
G. R. Carmichael ◽  
N. Bousserez ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Black Carbon ◽  
Optical Depth ◽  
Atmospheric Environment ◽  
Anthropogenic Emissions ◽  
Slight Reduction ◽  
Emission Inventories ◽  
Top Down ◽  
Aerosol Absorption

Abstract. Accurate estimates of the emissions and distribution of Southeast Asian (70–150° E, 11° S–55° N) black carbon (BC) are critical to studies of the atmospheric environment and climate change. Analysis of modeled BC concentrations compared to in situ observations indicates levels are underestimated over most of Southeast Asia when using any of four different emission inventories. We thus attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem model and its adjoint for April and October of 2006. Overwhelming enhancements, up to 500%, in anthropogenic BC emissions are shown after optimization over broad areas of Southeast Asia in April. In October, the optimization of anthropogenic emissions yields a slight reduction (1 ~ 5%) over India and parts of southern China, while emissions increase by 10 ~ 50% over eastern China. Observational data from in situ measurements and AERONET observations are used to evaluate the BC inversions and assess the bias between OMI and AERONET AAOD. Low biases in BC concentrations are improved or corrected in most eastern and central sites over China after optimization, while the constrained model still underestimates concentrations in Indian sites in both April and October, possibly as a consequence of low prior emissions. Model resolution errors may contribute up to a factor of 2.5 to the underestimate of surface BC concentrations over northern India. We also compare the optimized results using different anthropogenic emission inventories and discuss the sensitivity of top-down constraints on anthropogenic emissions with respect to biomass burning emissions. In addition, the impacts of different observation operators and a priori constraints on the optimization are investigated. Overall, despite these limitations and uncertainties, using OMI AAOD to constrain BC sources improves model representation of BC distributions, particularly over China.

Enthalpy and Momentum Fluxes during Hurricane Earl Relative to Underlying Ocean Features

2015 ◽  
Vol 143 (1) ◽  
pp. 111-131 ◽  
Author(s):  
Benjamin Jaimes ◽  
Lynn K. Shay ◽  
Eric W. Uhlhorn
Keyword(s):  
Thermal Structure ◽  
Heat Content ◽  
Sea Surface ◽  
Atmospheric Environment ◽  
Specific Humidity ◽  
Intensity Change ◽  
Surface Cooling ◽  
Near Surface ◽  
Sea Surface Cooling

Abstract Using dropsondes from 27 aircraft flights, in situ observations, and satellite data acquired during Tropical Cyclone Earl (category 4 hurricane), bulk air–sea fluxes of enthalpy and momentum are investigated in relation to intensity change and underlying upper-ocean thermal structure. During Earl’s rapid intensification (RI) period, ocean heat content (OHC) variability relative to the 26°C isotherm exceeded 90 kJ cm−2, and sea surface cooling was less than 0.5°C. Enthalpy fluxes of ~1.1 kW m−2 were estimated for Earl’s peak intensity. Daily sea surface heat losses of , , and kJ cm−2 were estimated for RI, mature, and weakening stages, respectively. A ratio of the exchange coefficients of enthalpy (CK) and momentum (CD) between 0.54 and 0.7 produced reliable estimates for the fluxes relative to OHC changes, even during RI; a ratio overestimated the fluxes. The most important result is that bulk enthalpy fluxes were controlled by the thermodynamic disequilibrium between the sea surface and the near-surface air, independently of wind speed. This disequilibrium was strongly influenced by underlying warm oceanic features; localized maxima in enthalpy fluxes developed over tight horizontal gradients of moisture disequilibrium over these eddy features. These regions of local buoyant forcing preferentially developed during RI. The overall magnitude of the moisture disequilibrium (Δq = qs − qa) was determined by the saturation specific humidity at sea surface temperature (qs) rather than by the specific humidity of the atmospheric environment (qa). These results support the hypothesis that intense local buoyant forcing by the ocean could be an important intensification mechanism in tropical cyclones over warm oceanic features.

scholarly journals Constraining black carbon aerosol over Asia using OMI aerosol absorption optical depth and the adjoint of GEOS-Chem

2015 ◽  
Vol 15 (18) ◽  
pp. 10281-10308 ◽  
Author(s):  
L. Zhang ◽  
D. K. Henze ◽  
G. A. Grell ◽  
G. R. Carmichael ◽  
N. Bousserez ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Black Carbon ◽  
Optical Depth ◽  
Atmospheric Environment ◽  
Anthropogenic Emissions ◽  
Slight Reduction ◽  
Emission Inventories ◽  
Top Down ◽  
Aerosol Absorption

Abstract. Accurate estimates of the emissions and distribution of black carbon (BC) in the region referred to here as Southeastern Asia (70–150° E, 11° S–55° N) are critical to studies of the atmospheric environment and climate change. Analysis of modeled BC concentrations compared to in situ observations indicates levels are underestimated over most of Southeast Asia when using any of four different emission inventories. We thus attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI (Ozone Monitoring Instrument) observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem (Goddard Earth Observing System – chemistry) model and its adjoint for April and October 2006. Overwhelming enhancements, up to 500 %, in anthropogenic BC emissions are shown after optimization over broad areas of Southeast Asia in April. In October, the optimization of anthropogenic emissions yields a slight reduction (1–5 %) over India and parts of southern China, while emissions increase by 10–50 % over eastern China. Observational data from in situ measurements and AERONET (Aerosol Robotic Network) observations are used to evaluate the BC inversions and assess the bias between OMI and AERONET AAOD. Low biases in BC concentrations are improved or corrected in most eastern and central sites over China after optimization, while the constrained model still underestimates concentrations in Indian sites in both April and October, possibly as a consequence of low prior emissions. Model resolution errors may contribute up to a factor of 2.5 to the underestimation of surface BC concentrations over northern India. We also compare the optimized results using different anthropogenic emission inventories and discuss the sensitivity of top-down constraints on anthropogenic emissions with respect to biomass burning emissions. In addition, the impacts of brown carbon, the formulation of the observation operator, and different a priori constraints on the optimization are investigated. Overall, despite these limitations and uncertainties, using OMI AAOD to constrain BC sources improves model representation of BC distributions, particularly over China.

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