The Moderate Resolution Imaging Spectroradiometer (MODIS) cloud product provides three separate 1 km resolution retrievals of cloud particle effective radii (re), derived from 1.6, 2.1 and 3.7 μm ...band observations. In this study, differences among the three size retrievals for maritime water clouds (designated as re,1.6re,2.1 and re,3.7) were systematically investigated through a series of case studies and global analyses. Substantial differences are found between re,3.7 and re,2.1 retrievals (Δre,3.7–2.1), with a strong dependence on cloud regime. The differences are typically small, within ±2 μm, over relatively spatially homogeneous costal stratocumulus cloud regions. However, for trade wind cumulus regimes, re,3.7 was found to be substantially smaller than re,2.1, sometimes by more than 10 μm. The correlation of Δre,3.7–2.1 with key cloud parameters, including the cloud optical thickness (τ), re and a cloud horizontal heterogeneity index (Hσ) derived from 250m resolution MODIS 0.86 μm band observations, were investigated using one month of MODIS Terra data. It was found that differences among the three re retrievals for optically thin clouds (τ < 5) are highly variable, ranging from −15 μm to 10 μm, likely due to the large MODIS retrieval uncertainties when the cloud is thin. The Δre,3.7–2.1 exhibited a threshold‐like dependence on both re,2.1 and Hσ. The re,3.7 is found to agree reasonably well with re,2.1 when re,2.1 is smaller than about 15 μm, but becomes increasingly smaller than re,2.1 once re,2.1 exceeds this size. All three re retrievals showed little dependence when cloud is relatively homogenous (Hσ < 0.3 defined as standard deviation divided by the mean for the 250 m pixels within a 1 km pixel retrieval). However, for inhomogeneous clouds (Hσ > 0.3), both re,1.6 and re,2.1 were seen to increase quickly with Hσ. On the other hand, re,3.7 statistics showed little dependence on Hσ and remained relatively stable over the whole range of Hσ values. Potential contributing causes to the substantial re,3.7 and re,2.1 differences are discussed. In particular, based on both 1‐D and 3‐D radiative transfer simulations, we have elucidated mechanisms by which cloud heterogeneity and 3‐D radiative effects can cause large differences between re,3.7 and re,2.1 retrievals for highly inhomogeneous clouds. Our results suggest that the contrast in observed Δre,3.7–2.1 between cloud regimes is correlated with increases in both cloud re and Hσ. We also speculate that in some highly inhomogeneous drizzling clouds, vertical structure induced by drizzle and 3‐D radiative effects might operate together to cause dramatic differences between re,3.7 and re,2.1 retrievals.
Key Points
MODIS effective radius retrieval for maritime water clouds investigated
Significant difference between re2.1 and re3.7 found
Potential reason for the difference investigated
In order to obtain the catalytic effects of K and Ca species on the biochar structure during in-situ tar H2O reforming over nascent biochar, the H-form/K-loaded/Ca-loaded rice husks were studied for ...the in-situ tar reforming in the two-stage fluidized bed/fixed bed reactor. The specific reaction pathway of K and Ca for tar reforming was investigated, associated with the changes of biochar structures, through the methods of ICP-AES, Raman, FTIR and XPS. The results indicate that the in-situ volatiles (tar and free radicals) H2O reforming over nascent biochar could be conducted by three possible ways: occupying reactive sites on biochar, changing biochar structures and/or changing the total/surface concentration of AAEM species. The mechanisms of in-situ tar H2O reforming by K and Ca species were different: tar cracking into low-quality tar or small-molecule gas may be catalyzed by K, while the combination of tar with biochar would be promoted by Ca. The volatilizations of K and Ca with the presence of volatiles were to a large extent in accordance with their valences (monovalent K+ and divalent Ca2+) and their boiling points. The subsequent transformation from the small aromatic ring systems to the larger ones occurred due to the volatile-biochar interaction. During the in-situ tar H2O reforming over biochar, K and Ca act as the active sites on biochar surface to promote the increase of active intermediates (CO bonds and COK/Ca), which promotes the tar-biochar interactions.
•Tar cracking is catalyzed by K, while combination of tar with biochar is promoted by Ca.•Volatilization of K and Ca with volatiles is dependent on their valences and boiling points.•Transformation from small aromatic rings to larger ones occurred due to the volatile-biochar interaction.•K and Ca act as active sites to promote increase of active intermediates for tar-biochar interaction.
Manufacturing is undergoing a paradigmatic shift as it assimilates and is transformed by machine learning and other cognitive technologies. A new paradigm usually necessitates a new framework to ...comprehend it fully, organise extant knowledge, identify gaps in knowledge, guide future research and practice, and synthesise new knowledge. Paradoxically, such a framework to guide the research and practice of ML in manufacturing remains absent. This paper attempts to fill this gap by presenting the interpretive model of manufacturing as an integrative framework for ML in manufacturing. A systematic hybrid literature review approach has been adopted to conduct both thematic and conceptual synthesis of the literature. The descriptive literature review method has been used to conduct a thematic synthesis of the literature. The framework synthesis method has been used to complete a conceptual synthesis of the literature. The resultant framework, the interpretive model of manufacturing, is articulated as consisting of scan, store, interpret, execute, and learn as its purposive components. Research questions have been identified for each of these components, as well as at their interfaces, to develop a comprehensive and systematic research agenda. Additional areas for extending research have also been identified. Implications for manufacturing operations, manufacturing strategy, and manufacturing policy have been drawn out for practitioners and policy makers.
Using synergetic effects of various sodium storage modes and materials to construct high power, high energy, and long cycling flexible sodium anode materials is significant and still challenging. ...Here, by advantageous functional integration of adsorption‐intercalation‐conversion sodium storage mechanisms, a 3D flexible fiber paper anode with the composition of Nb2O5@hard carbon@MoS2@soft carbon is designed and prepared. Based on the synergetic effects, it exhibits higher specific capacity than pure Nb2O5, with more excellent rate performance (245, 201, 155, 133, and 97 mAh g−1 at the current density of 0.2, 1, 5, 10, and 20 A g−1, respectively) than pure MoS2 as well as admirable long‐term cycling characteristics (≈82% capacity retention after 20 000 cycles at 5 A g−1). Relevant kinetics mechanisms are expounded in detail. This work can be helpful for preparing other types of hybrid and flexible electrodes for energy storage systems.
By advantageous functional integration of adsorption‐intercalation‐conversion mechanisms, a 3D flexible Nb2O5@hard carbon@MoS2@soft carbon fiber paper electrode is prepared. This hybrid anode can release the sodium storage advantages of all materials with the aid of synergetic effects. It displays excellent rate performance and long‐term cycling for over 20 000 cycles.
The CO2 solubilities (including CO2 Henry's constant) in physical- and chemical-based ILs/DESs and the COSMO-RS models describing these properties were comprehensively collected and summarized. The ...summarized results indicate that chemical-based ILs/DESs are superior to physical-based ILs/DESs for CO2 capture, especially those ILs have functionalized cation and anion, and superbase DESs; some of the superbase DESs have higher CO2 solubilities than those of ILs; the best physical- and chemical-based ILs, as well as physical- and chemical-based DESs are BMIMBF4 (4.20 mol kg−1), DETAHIm (11.91 mol kg−1), L-Arg-Gly 1:6 (4.92 mol kg−1) and TBD-EG 1:4 (12.90 mol kg−1), respectively. Besides the original COSMO-RS mainly providing qualitative predictions, six corrected COSMO-RS models have been proposed to improve the prediction performance based on the experimental data, but only one model is with universal parameters. The newly determined experimental results were further used to verify the perditions of original and corrected COSMO-RS models. The comparison indicates that the original COSMO-RS qualitatively predicts CO2 solubility for some but not all ILs/DESs, while the quantitative prediction is incapable at all. The original COSMO-RS is capable to predict CO2 Henry's constant qualitatively for both physical-based ILs and DESs, and quantitative prediction is only available for DESs. For the corrected COSMO-RS models, only the model with universal parameters provides quantitative predictions for CO2 solubility in physical-based DESs, while other corrected models always show large deviations (> 83%) compared with the experimental CO2 Henry's constants.
The CO2 solubility (including Henry's constant) in ILs/DESs and the COSMO-RS models describing these properties were collected, and compared with the original and corrected COSMO-RS prediction results. Then the best CO2 solubility and the performance of COSMO-RS models were achieved. Display omitted
The interface reaction is the focus of interface control in the graphene/Al composites, but its evolution processes are still unclear. The present work revealed the nucleation and growth mechanisms ...of the interfacial reaction product, aluminum carbide (Al4C3), in the graphene nanosheet (GNS)/Al composites. The nucleation of Al4C3 was found to mainly start at the open edge of GNSs due to the high chemical reactivity, and the formed Al4C3 was found to mostly locate either along or at an angle to the Al grain boundary, e.g. (i) ∼25° angle between Al4C3 (003) and Al (-111); (ii) Al4C3 (003)//Al (1-11); (iii) Al4C3 (003)//Al (002); (iv) Al4C3 (003)//Al (2-20). The growth of Al4C3 was controlled by the diffusional growth parallel to (003) plane and the nucleation growth perpendicular to (003) plane. Besides, the possible intermediate states, the C–Al interfacial transition zone, and the interfacial reaction transition phase were also observed. This work provides a theoretical basis for the further tailoring of interface bonding and property improvements of graphene/Al composites.
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The stadium is a wind-sensitive structure, and the tornado has a greater damage to the stadium. The Ward tornado generating device was used to simulate the wind load characteristics of the stadium ...during tornado action in order to investigate the wind load characteristics of the stadium. The results of this paper are compared with the experimental results to verify the accuracy of the simulation method. The wind load characteristics of the stadium and its most vulnerable location during a tornado are ascertained by examining the wind pressure coefficient and wind speed distribution law of the stadium's upper and lower surfaces with different swirl ratio. The influence of uniform wind and wind profile on the wind load of the stadium is explored by comparing and analyzing the wind pressure coefficient of the stadium surface with and without wind profile at the entrance of the wind field. The impact of varying ground roughness on the stadium is compared in order to ascertain how it affects the wind speed, stadium wind pressure, and vortex core radius. The vorticity of the stadium in the tornado wind field with different swirl ratios was compared and analyzed, and the influence of the stadium on the vorticity development of the wind field was explored. This study reveals the effects of swirl ratio, ground roughness and wind profile on the wind pressure, wind speed and vorticity of the stadium under tornadoes, and determines the most vulnerable location and the most unfavorable factors. The above research is helpful to provide reference for disaster prevention and mitigation of stadium structure design.
The productivity of the Amazon rainforest is constrained by the availability of nutrients, in particular phosphorus (P). Deposition of long‐range transported African dust is recognized as a ...potentially important but poorly quantified source of phosphorus. This study provides a first multiyear satellite‐based estimate of dust deposition into the Amazon Basin using three‐dimensional (3‐D) aerosol measurements over 2007–2013 from the Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP). The 7 year average of dust deposition into the Amazon Basin is estimated to be 28 (8–48) Tg a−1 or 29 (8–50) kg ha−1 a−1. The dust deposition shows significant interannual variation that is negatively correlated with the prior‐year rainfall in the Sahel. The CALIOP‐based multiyear mean estimate of dust deposition matches better with estimates from in situ measurements and model simulations than a previous satellite‐based estimate does. The closer agreement benefits from a more realistic geographic definition of the Amazon Basin and inclusion of meridional dust transport calculation in addition to the 3‐D nature of CALIOP aerosol measurements. The imported dust could provide about 0.022 (0.006–0.037) Tg P of phosphorus per year, equivalent to 23 (7–39) g P ha−1 a−1 to fertilize the Amazon rainforest. This out‐of‐basin phosphorus input is comparable to the hydrological loss of phosphorus from the basin, suggesting an important role of African dust in preventing phosphorus depletion on timescales of decades to centuries.
Key Points
About 28 Tg of Saharan dust is deposited into the Amazon yearly
African dust plays an important role in preventing phosphorus depletion
Ambiguity and inconsistency in model‐observation comparison is clarified
This article proposes an integer ambiguity determination method based on Beidou system-reflectometry (Beidou-R) observations of the carrier phase at the B1I and B3I frequencies. To enhance the ...accuracy of sea surface height (SSH) estimation, this study introduces a parallel filtering algorithm and an adaptive iterative fusion algorithm, enabling data fusion based on the variance at B1I and B3I frequencies. To validate and evaluate the proposed method, a coastal experiment was conducted at the Shenxian River. In this experiment, reflected signals from GEO and IGSO satellites were collected. Data analysis reveals that the method is effective, demonstrating that the root mean square error (RMSE) of SSH achieves 2.85 cm and 2.89 cm for PRN 04 and PRN 33, respectively. Furthermore, the impact of the elevation angle on measurement accuracy is analyzed. This study aims to propose a method to enhance coastal sea surface height estimation, offering potential advancements in sea surface altimetry.
The Moderate-Resolution Imaging Spectroradiometer (MODIS) level-2 (L2) cloud product (earth science data set names MOD06 and MYD06 for Terra and Aqua MODIS, respectively) provides pixel-level ...retrievals of cloud top properties (day and night pressure, temperature, and height) and cloud optical properties (optical thickness, effective particle radius, and water path for both liquid water and ice cloud thermodynamic phases-daytime only). Collection 6 (C6) reprocessing of the product was completed in May 2014 and March 2015 for MODIS Aqua and Terra, respectively. Here we provide an overview of major C6 optical property algorithm changes relative to the previous Collection 5 (C5) product. Notable C6 optical and microphysical algorithm changes include: 1) new ice cloud optical property models and a more extensive cloud radiative transfer code lookup table (LUT) approach; 2) improvement in the skill of the shortwave-derived cloud thermodynamic phase; 3) separate cloud effective radius retrieval data sets for each spectral combination used in previous collections; 4) separate retrievals for partly cloudy pixels and those associated with cloud edges; 5) failure metrics that provide diagnostic information for pixels having observations that fall outside the LUT solution space; and 6) enhanced pixel-level retrieval uncertainty calculations. The C6 algorithm changes can collectively result in significant changes relative to C5, though the magnitude depends on the data set and the pixel's retrieval location in the cloud parameter space. Example L2 granule and level-3 gridded data set differences between the two collections are shown. While the emphasis is on the suite of cloud optical property data sets, other MODIS cloud data sets are discussed when relevant.
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