Hasil untuk "Earthwork. Foundations"

M. Coppola, A. Battaglia, A. Battaglia et al.

<p>The Earth's strong radar surface return limits the detection of clouds and precipitation in the lowest part of the atmosphere by nadir-pointing spaceborne radars such as CloudSat and EarthCARE. The strength of the Earth's surface radar return is significantly reduced at non-zero incidence angles. The WIVERN (WInd Velocity Radar Nephoscope) 94 GHz radar, currently undergoing Phase-A studies by ESA, employs a 3 m antenna and conical radar sampling at high incidence angles. Here, the benefits of the narrow field of view and the reduction in the Earth's surface return for studying clouds and precipitation in the lowest kilometres of the atmosphere are quantified. The WIVERN radar is expected to improve the ratio of signal (hydrometeors) to clutter (surface return) over ice-free ocean surfaces and marginally worsen it over land and sea ice. The impact of these findings on the detection of light rainfall and snowfall near the Earth's surface is discussed.</p>

Biao Ma, Weichen Lu, Liang Yu et al.

The reduction of friction-induced noise is a crucial research area for enhancing vehicle comfort, and this paper proposes a method based on circular pit texture to achieve this goal. We conducted a long-term sliding friction test using a pin-on-disc friction and a wear test bench to verify the validity of this method. To compare the friction noise of different surfaces, texture units with varying line densities were machined on the surface of friction disk samples. The resulting friction-wear and noise characteristics of the samples were analyzed in conjunction with the microscopic morphology of the worn surfaces. The results indicate that surfaces with textures can delay the onset of squeal noise, and the pattern of its development differs from that of smooth surfaces. The noise reduction effect is most evident due to the proper distribution of textures that can form furrow-like wear marks at the wear interface. The finite element results demonstrate that this morphology can improve pressure distribution at the leading point and reduce the tendency of system instability.

Purushottam Das Gujrati

The review provides a pedagogical but comprehensive introduction to the foundations of a recently proposed statistical mechanics (μNEQT) of a stable nonequilibrium thermodynamic body, which may be either isolated or interacting. It is an extension of the well-established equilibrium statistical mechanics by considering microstates mk in an extended state space in which macrostates (obtained by ensemble averaging A^) are uniquely specified so they share many properties of stable equilibrium macrostates. The extension requires an appropriate extended state space, three distinct infinitessimals dα=(d,de,di) operating on various quantities q during a process, and the concept of reduction. The mechanical process quantities (no stochasticity) like macrowork are given by A^dαq, but the stochastic quantities C^αq like macroheat emerge from the commutator C^α of dα and A^. Under the very common assumptions of quasi-additivity and quasi-independence, exchange microquantities deqk such as exchange microwork and microheat become nonfluctuating over mk as will be explained, a fact that does not seem to have been appreciated so far in diverse branches of modern statistical thermodynamics (fluctuation theorems, quantum thermodynamics, stochastic thermodynamics, etc.) that all use exchange quantities. In contrast, dqk and diqk are always fluctuating. There is no analog of the first law for a microstate as the latter is a purely mechanical construct. The second law emerges as a consequence of the stability of the system, and cannot be violated unless stability is abandoned. There is also an important thermodynamic identity diQ≡diW ≥ 0 with important physical implications as it generalizes the well-known result of Count Rumford and the Gouy-Stodola theorem of classical thermodynamics. The μNEQT has far-reaching consequences with new results, and presents a new understanding of thermodynamics even of an isolated system at the microstate level, which has been an unsolved problem. We end the review by applying it to three different problems of fundamental interest.

V. Pidlutskyi, Oleksandr Piatkov, Vasyl Behan

The results of numerical modeling of the interaction between a multi-storey building on a pile foundation and the soil base in the "Lira-SAPR" software are presented. A comparison of the stress-strain state of foundation structures was performed using different methods for determining vertical stiffness (Rz) in single-node FE 57 (this element is designed to model the behavior of a pile together with the surrounding soil, similar to FE 56, and can implement the interaction with the "SOIL" system). Piles were modeled by a chain of single-node FE 57 connected by vertical bars. In the first variant, the calculation of the building was performed in the "Lira-SAPR" software. To determine the vertical stiffness in FE 57, a soil model with physical-mechanical characteristics was created, and layering was defined according to the engineering-geological cross-section in the "SOIL" system. The calculation of vertical stiffness took into account mutual influence and the model of the conditional foundation. In the second variant, the determination of vertical stiffness (Rz) in FE 57 was carried out using the "Plaxis 3D" software. The overall model of above-ground structures, foundations, and all necessary loads were created in the "Lira-SAPR" software. Subsequently, an export to "Plaxis 3D" was performed, where the soil was previously modeled as a three-dimensional soil mass (with characteristics and strengths of layers similar to those created in the "SOIL" system) using the "Hardening soil" behavior model. After the import into "Plaxis 3D," the analysis of the "Soil-Foundation-Structure" system was conducted, and the obtained values of vertical stiffness (Rz) in FE 57 were exported back to "Lira-SAPR". After the export of "refined" values of vertical stiffness to "Lira-SAPR", a general static analysis and comparison of the stress-strain state of foundation structures with the first calculation variant was performed. It was established that the vertical stiffness in FE 57 in the first variant is higher than in the second, accordingly, the total displacements for the first variant are smaller. The importance of using the connection between "Lira-SAPR" and "Plaxis 3D" or other specialized geotechnical software complexes was demonstrated to obtain more accurate results of the interaction of the "Soil-Foundation-Structure" system due to the possibility of using nonlinear soil models to better describe the behavior of the foundation.

V. Nosenko, Liudmyla Bondareva, Максим Khoronzhevskyi et al.

One of the most progressive problems of modern urban planning is the gradual decrease in areas suitable for construction, especially within the historical districts of cities. This prompts developers to increasingly develop sites in difficult engineering and geological conditions, which are often located within dense buildings. Today, the construction of multifunctional residential complexes combines the construction of high-rise residential sections and commercial real estate buildings with multi-level parking lots, which are often located in close proximity to each other. Often, the sequence of construction of these buildings is stretched over years or even decades, for example, due to an unfavorable economic climate or the instability of the political situation in the country, which leads to the commissioning of only certain stages of construction. The subsequent resumption of construction work requires taking into account the mutual impact of new construction and observations of previously constructed buildings during the construction of new structures. The execution of deep pits at the stage of laying the foundations of new buildings, as well as the substantial weight of high-rise buildings, causes a change in the stress-strain state of the adjacent soil massif, so designers face the task of determining the impact of such construction on the adjacent buildings. This article presents the results of a study of the change in the stress-strain state of load-bearing structures and foundations an existing building, taking into account the mutual impact of an adjacent high-rise section of a residential complex. The calculations were performed in two independent software systems Plaxis 3D and LIRA-FEM, in the spatial formulation of tasks, for a comprehensive assessment of the SSS of the system "soil base-foundation-superstructure".  The zone of impact of new construction on the adjacent buildings, the values and character of additional displacements of foundations of adjacent structures are determined. The regularities of changes in the calculated forces in piles are shown, which indicate a decrease in axial forces in piles up to two times at the interface with the foundations of the new building and an increase in the load on the piles of the central zone by up to 17%. The obtained results show a tendency to redistribute stresses in the foundation slab from the bearing zones to the span zones, as well as in the bearing vertical structures of the lower floor of the existing building.

V. Ruchkivskyi

A study of the influence of application of an engineering protective screen made of small-diameter driven piles on the existing building deformations, caused by the arrangement of the pit fence made of bored piles, was carried out. The study was carried out with the help of numerical modeling using the method of finite elements, which allowed to display the work of the system "soil base - engineering protective structures - the foundation of the existing building" with different parameters of the protective screen. The influence of the following parameters is shown: 1) the depth of laying the protective screen L in relation to the depth of the compressible soil zone (Hst). 2) the position of the protective screen between the retaining structures of the pit and the existing building. 3) rigidity of the screen – the ratio of the step to the diameter of the piles of the engineering protective screen. 4) the distance between the existing building and the pit in relation to the depth of the enclosing structures of the pit of the new construction. The tasks were modeled in a spatial arrangement with the task of the system "soil base - enclosing constructions of the pit - protective screen - foundations of the existing building". The soil environment was modeled using the Hardening Soil Model. The calculation was carried out in stages. The variation of the parameters of the protective screen was carried out for the historical building, which in most cases was made according to a rigid wall construction scheme with strip foundations. The foundation depth is 1.2 - 3.0 m and the foundation width is 1-2 m. The average pressure under the foundation is 150-250 kPa. The rational depth of the foundation and the position of the protective screen between the existing building and the pit of the new construction were established. The area of effective application of the protective screen was revealed, depending on the distance between the building and the pit fence. The effective stiffness is established depending on the change in the relative distance between the poles of the protective screen.

Manoj Puthia, Jan K. Marzinek, Ganna Petruk et al.

Apolipoprotein E (APOE) is a lipid-transport protein that functions as a key mediator of lipid transport and cholesterol metabolism. Recent studies have shown that peptides derived from human APOE display anti-inflammatory and antimicrobial effects. Here, we applied in vitro assays and fluorescent microscopy to investigate the anti-bacterial effects of full-length APOE. The interaction of APOE with endotoxins from Escherichia coli was explored using surface plasmon resonance, binding assays, transmission electron microscopy and all-atom molecular dynamics (MD) simulations. We also studied the immunomodulatory activity of APOE using in vitro cell assays and an in vivo mouse model in combination with advanced imaging techniques. We observed that APOE exhibits anti-bacterial activity against several Gram-negative bacterial strains of Pseudomonas aeruginosa and Escherichia coli. In addition, we showed that APOE exhibits a significant binding affinity for lipopolysaccharide (LPS) and lipid A as well as heparin. MD simulations identified the low-density lipoprotein receptor (LDLR) binding region in helix 4 of APOE as a primary binding site for these molecules via electrostatic interactions. Together, our data suggest that APOE may have an important role in controlling inflammation during Gram-negative bacterial infection.

Y. Fabel, B. Nouri, S. Wilbert et al.

<p>Semantic segmentation of ground-based all-sky images (ASIs) can provide high-resolution cloud coverage information of distinct cloud types, applicable for meteorology-, climatology- and solar-energy-related applications. Since the shape and appearance of clouds is variable, and there is high similarity between cloud types, a clear classification is difficult. Therefore, most state-of-the-art methods focus on the distinction between cloudy and cloud-free pixels without taking into account the cloud type. On the other hand, cloud classification is typically determined separately at the image level, neglecting the cloud's position and only considering the prevailing cloud type. Deep neural networks have proven to be very effective and robust for segmentation tasks; however they require large training datasets to learn complex visual features. In this work, we present a self-supervised learning approach to exploit many more data than in purely supervised training and thus increase the model's performance. In the first step, we use about 300 000 ASIs in two different pretext tasks for pretraining. One of them pursues an image reconstruction approach. The other one is based on the <i>DeepCluster</i> model, an iterative procedure of clustering and classifying the neural network output. In the second step, our model is fine-tuned on a small labeled dataset of 770 ASIs, of which 616 are used for training and 154 for validation. For each of them, a ground truth mask was created that classifies each pixel into <i>clear sky</i> or a <i>low-layer</i>, <i>mid-layer</i> or <i>high-layer</i> cloud. To analyze the effectiveness of self-supervised pretraining, we compare our approach to randomly initialized and pretrained ImageNet weights using the same training and validation sets. Achieving 85.8 % pixel accuracy on average, our best self-supervised model outperforms the conventional approaches of random (78.3 %) and pretrained ImageNet initialization (82.1 %). The benefits become even more evident when regarding precision, recall and intersection over union (IoU) of the respective cloud classes, where the improvement is between 5 and 20 percentage points. Furthermore, we compare the performance of our best model with regards to binary segmentation with a clear-sky library (CSL) from the literature. Our model outperforms the CSL by over 7 percentage points, reaching a pixel accuracy of 95 %.</p>

Mykhailo Sukach

У місті Вейхай (провінція Шаньдун, Китай) відбулося «Онлайн-відео роуд-шоу», присвячене підбору зарубіжних талантів високо класу. Понад 20 підприємців і кілька українських науковців із захопленням спілкувалися через онлайн-відео, обговорюючи стикування технологій у сферах сільського господарства, медичного лікування, автоматизації тощо. Було розпочато нову спробу хмарного міжнародного роуд-шоу – прелюдію до «China Weihai International Talents, Innovation and Entrepreneurship Conference». Захід був організований Вейхайським муніципальним бюро кадрових ресурсів та соціального забезпечення та проведення Управлінням людських ресурсів та соціального забезпечення (Weihai Talent Work). Після чисельних відборів і поєднання з виробничою ситуацією та реальними потребами парку підприємств було визначено план заходів для онлайн-стикування з українською командою науковців. Україна має міцну науково-дослідну базу, достатній запас висококласних талантів та потужну технічну силу. У спільних роботах брали участь п'ять академіків і спеціалістів, які зацікавили підприємства Вейхаю своїми технічними досягненнями.

L. Haszpra, L. Haszpra, Z. Barcza et al.

<p>Although small rural settlements are only minor individual sources of greenhouse gases and air pollution, their high overall occurrence can significantly contribute to the total emissions of a region or country. Emissions from a rural lifestyle may be remarkably different than those of urban and industrialized regions, but nevertheless they have hardly been studied so far. Here, flux measurements at a tall-tower eddy covariance monitoring site and the footprint model FFP are used to determine the real-world wintertime CO, N<span class="inline-formula">₂</span>O, and CO<span class="inline-formula">₂</span> emissions of a small village in western Hungary. The recorded emission densities, dominantly resulting from residential heating, are 3.5, 0.043, and 72 <span class="inline-formula">µ</span>g m<span class="inline-formula">⁻²</span> s<span class="inline-formula">⁻¹</span> for CO, N<span class="inline-formula">₂</span>O, and CO<span class="inline-formula">₂</span>, respectively. While the measured CO and CO<span class="inline-formula">₂</span> emissions are comparable to those calculated using the assumed energy consumption and applying the according emission factors, the nitrous oxide emissions exceed the expected value by a magnitude. This may indicate that the nitrous oxide emissions are significantly underestimated in the emission inventories, and modifications in the methodology of emission calculations are necessary. Using a three-dimensional forward transport model, we further show that, in contrast to the flux measurements, the concentration measurements at the regional background monitoring site are only insignificantly influenced by the emissions of the nearby village.</p>

Irene Amerini, A. Anagnostopoulos, Luca Maiano et al.

In the last two decades, we have witnessed an immense increase in the use of multimedia content on the internet, for multiple applications ranging from the most innocuous to very critical ones. Naturally, this emergence has given rise to many types of threats posed when this content can be manipulated/used for malicious purposes. For example, fake media can be used to drive personal opinions, ruining the image of a public figure, or for criminal activities such as terrorist propaganda and cyberbullying. The research community has of course moved to counter attack these threats by designing manipulation-detection systems based on a variety of techniques, such as signal processing, statistics, and machine learning. This research and practice activity has given rise to the field of multimedia forensics. The success of deep learning in the last decade has led to its use in multimedia forensics as well. In this survey, we look at the latest trends and deep-learning-based techniques introduced to solve three main questions investigated in the field of multimedia forensics. We begin by examining the manipulations of images and videos produced with editing tools, reporting the deep-learning approaches adopted to Irene Amerini, Aris Anagnostopoulos, Luca Maiano and Lorenzo Ricciardi Celsi (2021), “Deep Learning for Multimedia Forensics”, Foundations and Trends® in Computer Graphics and Vision: Vol. 12, No. 4, pp 309–457. DOI: 10.1561/0600000096. Full text available at: http://dx.doi.org/10.1561/0600000096

K. Onyelowe, Ifeyinwa Ijeoma Obianyo

Abstract The influence of moisture migration in the form of GF on the morphology of lateritic soil has been studied with laboratory experiments. This was important due to the effect of adsorbed moisture during molding moisture addition in a stabilization protocol that gives rise to hydration. In addition, moisture adsorption and absorption play a very vital engineering role during the seasonal changes of wet and dry seasons when the water table rises and drops. This occurrence brings about alternate effects of wetting and drying of hydraulically bound structures like in pavement foundations. Therefore, it was pertinent to study how these changes affect soil microstructure to enable good design decisions. The soil used in this exercise was classified as highly plastic, poorly graded A-7-6 soil group according to AASHTO classification method. The soil was mixed with various proportions of quarry fines under different molding moisture conditions and the specimens were prepared for scanning electron microscopy (SEM) exposure. The results of the SEM exposure showed that GF applied here as molding moisture improve the agglomeration of treated soil particles to form flocs in a stabilization process. However, the microspores and crack propagation were observed more in the structure with less amount of quarry fine, i. e., at 2% QF than that at 4% QF. This showed the pozzolanic effect of QF on soil under the influence of GF. GF in all its forms should be studied for sustainable earthwork design and construction.

G. Carcassi, C. Aidala

To answer foundational questions in physics, physicists turn more and more to abstract advanced mathematics, even though its physical significance may not be immediately clear. What if we started to borrow ideas and approaches, with appropriate modifications, from the foundations of mathematics? In this paper we explore this route. In reverse mathematics one starts from theorems and finds the minimum set of axioms required for their derivation. In reverse physics we want to start from laws or more specific results, and find the physical concepts and starting points that recover them. We want to understand what physical results are implied by which physical assumptions. As an example of the technique, we will see six different characterizations of classical mechanics, show that the uncertainty principle depends only on the entropy bound on pure states and recast the third law of thermodynamics in terms of the entropy of an empty system. We believe the approach can provide greater insights into both current and new physical theories, put the physical concepts at the forefront of the discussion and provide a more unified view of physics by highlighting common patterns and ideas across different physical theories.

R. A. Wernis, R. A. Wernis, N. M. Kreisberg et al.

<p>Aerosols are a source of great uncertainty in radiative forcing predictions and have poorly understood health impacts. Most aerosol mass is formed in the atmosphere from reactive gas-phase organic precursors, forming secondary organic aerosol (SOA). Semivolatile organic compounds (SVOCs) (effective saturation concentration, <span class="inline-formula"><i>C</i>^*</span>, of 10<span class="inline-formula">⁻¹</span>–10<span class="inline-formula">³</span> <span class="inline-formula">µg m⁻³</span>) comprise a large fraction of organic aerosol, while intermediate-volatility organic compounds (IVOCs) (<span class="inline-formula"><i>C</i>^*</span> of 10<span class="inline-formula">³</span>–10<span class="inline-formula">⁶</span> <span class="inline-formula">µg m⁻³</span>) and volatile organic compounds (VOCs) (<span class="inline-formula"><i>C</i>^*</span> <span class="inline-formula">≥</span> 10<span class="inline-formula">⁶</span> <span class="inline-formula">µg m⁻³</span>) are gas-phase precursors to SOA and ozone.</p> <p>The Comprehensive Thermal Desorption Aerosol Gas Chromatograph (cTAG) is the first single instrument simultaneously quantitative for a broad range of compound-specific VOCs, IVOCs and SVOCs. cTAG is a two-channel instrument which measures concentrations of C<span class="inline-formula">₅</span>–C<span class="inline-formula">₁₆</span> alkane-equivalent-volatility VOCs and IVOCs on one channel and C<span class="inline-formula">₁₄</span>–C<span class="inline-formula">₃₂</span> SVOCs on the other coupled to a single high-resolution time-of-flight mass spectrometer, achieving consistent quantification across 15 orders of magnitude of vapor pressure. cTAG obtains concentrations hourly and gas–particle partitioning for SVOCs every other hour, enabling observation of the evolution of these species through oxidation and partitioning into the particle phase. Online derivatization for the SVOC channel enables detection of more polar and oxidized species.</p> <p>In this work we present design details and data evaluating key parameters of instrument performance such as I/VOC collector design optimization, linearity and reproducibility of calibration curves obtained using a custom liquid evaporation system for I/VOCs and the effect of an ozone removal filter on instrument performance. Example timelines of precursors with secondary products are shown, and analysis of a subset of compounds detectable by cTAG demonstrates some of the analytical possibilities with this instrument.</p>

B. W. Roberts, J. Weatherall

S. Favrichon, S. Favrichon, C. Jimenez et al.

<p>Microwave remote sensing can be used to monitor the time evolution of some key parameters over land, such as land surface temperature or surface water extent. Observations are made with instruments, such as the Scanning Microwave Multichannel Radiometer (SMMR) before 1987, the Special Sensor Microwave/Imager (SSM/I) and the subsequent Special Sensor Microwave Imager/Sounder (SSMIS) from 1987 and still operating, and the more recent Global Precipitation Measurement Microwave Imager (GMI). As these instruments differ on some of their characteristics and use different calibration schemes, they need to be inter-calibrated before long-time-series products can be derived from the observations. Here an inter-calibration method is designed to remove major inconsistencies between the SMMR and other microwave radiometers for the 18 and 37&thinsp;<span class="inline-formula">GHz</span> channels over continental surfaces. Because of a small overlap in observations and a <span class="inline-formula">∼6</span>&thinsp;<span class="inline-formula">h</span> difference in overpassing times between SMMR and SSM/I, GMI was chosen as a reference despite the lack of a common observing period. The diurnal cycles from 3 years of GMI brightness temperatures are first calculated and then used to evaluate SMMR differences. Based on a statistical analysis of the differences, a simple linear correction is implemented to calibrate SMMR on GMI. This correction is shown to also reduce the biases between SMMR and SSM/I, and can then be applied to SMMR observations to make them more coherent with existing data records of microwave brightness temperatures over continental surfaces.</p>

J. Bak, J. Bak, X. Liu et al.

<p>We evaluate different sets of high-resolution ozone absorption cross-section data for use in atmospheric ozone profile measurements in the Hartley and Huggins bands with a particular focus on BDM 1995 (Daumont et al. 1992; Brion et al., 1993; Malicet et al., 1995), currently used in our retrievals, and a new laboratory dataset by Birk and Wagner (2018) (BW). The BDM cross-section data have been recommended to use for retrieval of ozone profiles using spaceborne nadir-viewing backscattered ultraviolet (BUV) measurements since its improved performance was demonstrated against other cross-sections including Bass and Paur (1985) (BP) and those of Serdyuchenko et al. (2014) and Gorshelev et al. (2014) (SER) by the “Absorption Cross-Sections of Ozone” (ACSO) activity. The BW laboratory data were recently measured within the framework of the European Space Agency (ESA) project SEOM-IAS (Scientific Exploitation of Operational Missions – Improved Atmospheric Spectroscopy Databases) to provide an advanced absorption cross-section database. The BW cross-sections are made from measurements at more temperatures and in a wider temperature range than BDM, especially for low temperatures. Relative differences of cross-sections between BW and BDM range from <span class="inline-formula">∼2</span>&thinsp;% at shorter UV wavelengths to <span class="inline-formula">∼5</span>&thinsp;% at longer UV wavelengths at warm temperatures. Furthermore, these differences dynamically increase by up to <span class="inline-formula">±40</span>&thinsp;% at cold temperatures due to no BDM measurements having been made below 218&thinsp;K. We evaluate the impact of using different cross-sections on ozone profile retrievals from Ozone Monitoring Instrument (OMI) measurements. Correspondingly, this impact leads to significant differences in individual ozone retrievals by up to 50&thinsp;% in the tropopause where the coldest atmospheric temperatures are observed. Bottom atmospheric layers illustrate the significant change of the retrieved ozone values, with differences of 20&thinsp;% in low latitudes, which is not the case in high latitudes because the ozone retrievals are mainly controlled by a priori ozone information in high latitudes due to less photon penetration down to the lower troposphere. Validation with ozonesonde observations demonstrates that BW and BDM retrievals show altitude-dependent bias oscillations of similar magnitude relative to ozonesonde measurements, much smaller than those of both BP and SER retrievals. However, compared to BDM, BW retrievals show significant reduction in standard deviation, by up to 15&thinsp;%, especially at the coldest atmospheric temperatures. Such improvement is achieved mainly by the better characterization of the temperature dependence of ozone absorption.</p>

E. A. Riley, J. M. Kleiss, L. D. Riihimaki et al.

<p>Cloud cover estimates of single-layer shallow cumuli obtained from narrow field-of-view (FOV) lidar–radar and wide-FOV total sky imager (TSI) data are compared over an extended period (2000–2017 summers) at the established United States Atmospheric Radiation Measurement mid-continental Southern Great Plains site. We quantify the impacts of two factors on hourly and sub-hourly cloud cover estimates: (1) instrument-dependent cloud detection and data merging criteria and (2) FOV configuration. Enhanced observations at this site combine the advantages of the ceilometer, micropulse lidar (MPL) and cloud radar in merged data products. Data collected by these three instruments are used to calculate narrow-FOV cloud fraction (CF) as a temporal fraction of cloudy returns within a given period. Sky images provided by TSI are used to calculate the wide-FOV fractional sky cover (FSC) as a fraction of cloudy pixels within a given image. To assess the impact of the first factor on CF obtained from the merged data products, we consider two additional subperiods (2000–2010 and 2011–2017 summers) that mark significant instrumentation and algorithmic advances in the cloud detection and data merging. We demonstrate that CF obtained from ceilometer data alone and FSC obtained from sky images provide the most similar and consistent cloud cover estimates; hourly bias and root-mean-square difference (RMSD) are within 0.04 and 0.12, respectively. However, CF from merged MPL–ceilometer data provides the largest estimates of the multiyear mean cloud cover, about 0.12 (35&thinsp;%) and 0.08 (24&thinsp;%) greater than FSC for the first and second subperiods, respectively. CF from merged ceilometer–MPL–radar data has the strongest subperiod dependence with a bias of 0.08 (24&thinsp;%) compared to FSC for the first subperiod and shows no bias for the second subperiod. The strong period dependence of CF obtained from the combined ceilometer–MPL–radar data is likely results from a change in what sensors are relied on to detect clouds below 3&thinsp;km. After 2011, the MPL stopped being used for cloud top height detection below 3&thinsp;km, leaving the radar as the only sensor used in cloud top height retrievals. To quantify the FOV impact, a narrow-FOV FSC is derived from the TSI images. We demonstrate that FOV configuration does not modify the bias but impacts the RMSD (0.1 hourly, 0.15 sub-hourly). In particular, the FOV impact is significant for sub-hourly observations, where 41&thinsp;% of narrow- and wide-FOV FSC differ by more than 0.1. A new “quick-look” tool is introduced to visualize impacts of these two factors through integration of CF and FSC data with novel TSI-based images of the spatial variability in cloud cover. The influence of cloud field organization, such cloud streets parallel to the wind direction, on narrow- and wide-FOV cloud cover estimates can be visually assessed.</p>

K. L. Chan, M. Wiegner, J. van Geffen et al.

<p>We present two-dimensional scanning Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations of nitrogen dioxide (<span class="inline-formula">NO₂</span>) and formaldehyde (HCHO) in Munich. Vertical columns and vertical distribution profiles of aerosol extinction coefficient, <span class="inline-formula">NO₂</span> and HCHO are retrieved from the 2D MAX-DOAS observations. The measured surface aerosol extinction coefficients and <span class="inline-formula">NO₂</span> mixing ratios derived from the retrieved profiles are compared to in situ monitoring data, and the surface <span class="inline-formula">NO₂</span> mixing ratios show a good agreement with in situ monitoring data with a Pearson correlation coefficient (<span class="inline-formula"><i>R</i></span>) of 0.91. The aerosol optical depths (AODs) show good agreement as well (<span class="inline-formula"><i>R</i> = 0.80</span>) when compared to sun photometer measurements. Tropospheric vertical column densities (VCDs) of <span class="inline-formula">NO₂</span> and HCHO derived from the MAX-DOAS measurements are also used to validate Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI) satellite observations. Monthly averaged data show a good correlation; however, satellite observations are on average 30&thinsp;% lower than the MAX-DOAS measurements. Furthermore, the MAX-DOAS observations are used to investigate the spatiotemporal characteristic of <span class="inline-formula">NO₂</span> and HCHO in Munich. Analysis of the relations between aerosol, <span class="inline-formula">NO₂</span> and HCHO shows higher aerosol-to-HCHO ratios in winter, which reflects a longer atmospheric lifetime of secondary aerosol and HCHO during winter. The analysis also suggests that secondary aerosol formation is the major source of these aerosols in Munich.</p>

M. Azrief Azahar, N. Farhan Zakiran Mahadi, Qusanssori Noor bin Rusli et al.

Site investigations for various infrastructure is traditionally done using boreholes drilled through various strata, logging of boreholes, sampling of strata and laboratory testing to assess engineering properties and infer behaviour of slopes, soft soils, embankments and foundations. Geophysics is still not used as a standard tool by most engineers due to the perception that it is not well-established science or that the results are unreliable. This paper outlines how Engineering and Geophysics can be integrated by having a well-balanced team with all the team members understand the fundamentals of each area. This is demonstrated by case histories for site investigations and earthworks quality assessment. The variety of geophysical methods available for site investigations, their applications, interpretations are presented. The paper describes how cost of investigations can be reduced and the risk of ground variations can be reduced by applying geophysics in geotechnical investigations.