Hasil untuk "Earthwork. Foundations"

M. Pashayi, M. Satari, M. Momeni Shahraki

<p>Multi-layer aerosol optical depth (AOD) estimation with sufficient spatial and temporal resolution is crucial for effective aerosol monitoring, given the significant variations over time and space. While ground-based observations provide detailed vertical profiles, satellite data are essential for addressing the spatial and temporal gaps. This study utilizes profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) to estimate vertical AOD values at 1.5, 3, 5, and 10 km layers. These estimations are achieved with spatial and temporal resolutions of 3 km <span class="inline-formula">×</span> 3 km and 15 min, respectively, over the European troposphere. We employed machine learning models – XGBoost (XGB) and random forest (RF) – trained on SEVIRI data from 2017 to 2018 for the estimations. Validation using CALIOP AOD retrievals in 2019 confirmed the reliability of our findings, emphasizing the importance of wind speed (Ws) and wind direction (Wd) in improving AOD estimation accuracy. A comparison between seasonal and annual models revealed slight variations in accuracy, leading to the selection of annual models as the preferred approach for estimating SEVIRI multi-layer AOD values. Among the annual models, the XGB model demonstrated superior performance over the RF model at all four layers, yielding more reliable AOD estimations with <span class="inline-formula"><i>R</i>²</span> values of 0.99, 0.97, 0.98, and 0.98 for the four layers from low- to high-altitude layers. Further validation using data from European Aerosol Research Lidar Network (EARLINET) stations across Europe in 2020 indicated that the XGB model still achieved better agreement with EARLINET AOD profiles, with <span class="inline-formula"><i>R</i>²</span> values of 0.86, 0.80, 0.75, and 0.59 and RMSE values of 0.022, 0.012, 0.015, and 0.005. We performed a qualitative validation of multi-layer AOD estimations by comparing spatial trends with CALIOP AOD retrievals for SEVIRI pixels on four dates in 2019, showing strong agreement across varying AOD levels. Additionally, the model successfully estimated AOD at 15 min intervals for two real events – a Saharan dust plume and the Mount Etna eruption – revealing consistent physical characteristics, including long-range transport in the upper layers and a gradual increase in AOD from lower to higher tropospheric layers during volcanic events. The results demonstrate that the proposed method facilitates comprehensive monitoring of AOD behavior throughout the four vertical layers of the troposphere, offering important insights into the dynamics of aerosol occurrence.</p>

R. Duren, D. Cusworth, A. Ayasse et al.

<p>The Carbon Mapper emissions monitoring system contributes to the broader ecosystem of greenhouse gas observations by locating and quantifying CH<span class="inline-formula">₄</span> and CO<span class="inline-formula">₂</span> super emitters at facility scale across priority regions globally and making the data accessible and actionable. The system includes observing platforms, an operational monitoring strategy optimized for mitigation impact, and a data platform that delivers CH<span class="inline-formula">₄</span> and CO<span class="inline-formula">₂</span> data products for diverse stakeholders. Operational scale-up of the system is centered around a new constellation of hyperspectral satellites. The Carbon Mapper Coalition (hereafter Tanager) satellites are each equipped with an imaging spectrometer instrument designed by NASA's Jet Propulsion Laboratory that are assembled, launched and operated by Planet Labs. The first Tanager satellite (Tanager-1) was launched 16 August 2024 completed commissioning in January 2025 and continued to improve observational efficiency through summer 2025. Planet is currently working to expand the constellation to four Tanagers. Each imaging spectrometer instrument has a spectral range of about 400–2500 nm, 5 nm spectral sampling, a nadir spatial resolution of 30 m, and nadir swath width of about 19 km at the lowest orbital altitude. Each satellite is capable of imaging 250 000 km<span class="inline-formula">²</span> per day on average. By combining the results of independent controlled release testing with empirical evaluation of the radiometric, spectral, spatial, and retrieval noise performance of the Tanager-1 spectrometer, we predict minimum detection limits of about 64–126 kgCH<span class="inline-formula">₄</span> h<span class="inline-formula">⁻¹</span> for CH<span class="inline-formula">₄</span> point sources and about 10 078–18 994 kgCO<span class="inline-formula">₂</span> h<span class="inline-formula">⁻¹</span> for CO<span class="inline-formula">₂</span> point sources for images with 25 % albedo, 45° solar zenith angle, and 3 m s<span class="inline-formula">⁻¹</span> wind speed. A review of the first 11 months of Tanager-1 CH<span class="inline-formula">₄</span> and CO<span class="inline-formula">₂</span> observations including initial validation with coordinated aircraft under-flights and non-blind controlled release testing indicates that the system is meeting performance requirements and, in many cases, surpassing expectations. We also present early evaluations in challenging onshore and offshore observational conditions and summarize the first use of Tanager data to guide the timely mitigation of a CH<span class="inline-formula">₄</span> super emitter.</p>

J. E. Katona, J. E. Katona, M. de la Torre Juárez et al.

<p>Polarimetric radio occultations (PROs) of the Global Navigation Satellite System are able to characterize precipitation structure and intensity. Prior studies have shown the relationship between precipitation and water vapor pressure columns, known as the “precipitation pickup.” Less is known about the relationship between the vertical distributions of temperature and moisture globally within precipitating scenes as measured from space. This work uses cluster analysis of PRO to explore how the vertical distributions of temperature and moisture – combined into PRO refractivity – relate to vertical distributions of precipitation and moisture variables. We evaluate the ability of <span class="inline-formula"><i>k</i></span>-means clustering to find relationships among PRO polarimetric phase difference, refractivity, liquid water path (LWP), ice water path (IWP), and water vapor pressure using over 2 years of data matched between the Global Precipitation Measurement (GPM) mission and the radio occultations (ROs) and heavy precipitation (HP) demonstration mission on board the Spanish Paz spacecraft (ROHP-PAZ). A polytropic potential refractivity model for polytropic atmospheres is introduced to ascertain how different vertical thermodynamic profiles that can occur during different precipitation scenarios are related to changes in the polytropic index and thereby vertical heat transfer rates. The cluster analyses suggest a relationship between the amplitude and shape of deviations from the potential refractivity model and water vapor pressure. These analyses also confirm a positive correlation between vertical shapes of polarimetric phase difference and both LWP and IWP. For certain values, the coefficients of the polytropic potential refractivity model flag physical vs. nonphysical retrievals and indicate when a profile has little to no moisture. The study reveals a similar relationship between the clustering for these coefficients and different water vapor pressure profiles.</p>

Fu Du, Liping He, Jian Pan et al.

E. Bell, C. W. O'Dell, T. E. Taylor et al.

<p>The Atmospheric Carbon Observations from Space (ACOS) retrieval algorithm has been delivering operational column-averaged carbon dioxide dry-air mole fraction (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="27a059aabe1b5f05045fb73febdad69a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-16-109-2023-ie00001.svg" width="25pt" height="14pt" src="amt-16-109-2023-ie00001.png"/></svg:svg></span></span>​​​​​​​) data for the Orbiting Carbon Observatory (OCO) missions since 2014. The ACOS Level 2 Full Physics (L2FP) algorithm retrieves a number of parameters, including aerosol and surface properties, in addition to atmospheric CO<span class="inline-formula">₂</span>. Past analysis has shown that while the ACOS retrieval meets mission precision requirements of 0.1 %–0.5 % in <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="78de0ae35d5858ad9c211be9b5f6c4ec"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-16-109-2023-ie00002.svg" width="25pt" height="14pt" src="amt-16-109-2023-ie00002.png"/></svg:svg></span></span>, residual biases and some sources of error remain unaccounted for <span class="cit" id="xref_paren.1">(<a href="#bib1.bibx58">Wunch et al.</a>, <a href="#bib1.bibx58">2017</a>; <a href="#bib1.bibx56">Worden et al.</a>, <a href="#bib1.bibx56">2017</a>; <a href="#bib1.bibx51">Torres et al.</a>, <a href="#bib1.bibx51">2019</a>)</span>. Forward model and other errors can lead to systematic biases in the retrieved <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="afb11e248386eadb3d253ed6526b3434"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-16-109-2023-ie00003.svg" width="25pt" height="14pt" src="amt-16-109-2023-ie00003.png"/></svg:svg></span></span>, which are often correlated with these additional retrieved parameters. The characterization of such biases is particularly essential to urban- and local-scale emissions studies, where it is critical to accurately distinguish source signals relative to background concentrations <span class="cit" id="xref_paren.2">(<a href="#bib1.bibx28">Nassar et al.</a>, <a href="#bib1.bibx28">2017</a>; <a href="#bib1.bibx23">Kiel et al.</a>, <a href="#bib1.bibx23">2021</a>)</span>. In this study we explore algorithm-induced biases through the use of simulated OCO-3 snapshot area mapping (SAM) mode observations, which offer a unique window into these biases with their wide range of viewing geometries over a given scene. We focus on a small percentage of SAMs in the OCO-3 vEarly product which contains artificially strong across-swath <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="8ccdaee3f4f494c6ed7cda3cb213792a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-16-109-2023-ie00004.svg" width="25pt" height="14pt" src="amt-16-109-2023-ie00004.png"/></svg:svg></span></span> biases spanning several parts per million, related to observation geometry. We investigate the causes of swath bias by using the timing and geometry of real OCO-3 SAMs to retrieve <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5a4a1b36d0ffc6ab2cbea83218996019"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-16-109-2023-ie00005.svg" width="25pt" height="14pt" src="amt-16-109-2023-ie00005.png"/></svg:svg></span></span> from custom simulated Level 1b radiance spectra. By building relatively simple scenes and testing a variety of parameters, we find that aerosol is the primary driver of swath bias, with a complex combination of viewing geometry and aerosol optical properties contributing to the strength and pattern of the bias. Finally, we seek to understand successful mitigation of swath bias in the new OCO-3 version 10 data product. Results of this study may be useful in uncovering other remaining sources of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="665a9135b0ec1acadcb95a0c37eb3e28"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-16-109-2023-ie00006.svg" width="25pt" height="14pt" src="amt-16-109-2023-ie00006.png"/></svg:svg></span></span> bias and may help minimize similar retrieval biases for both present missions (GOSAT, GOSAT-2, OCO-2, OCO-3, TanSat) and future missions (e.g., MicroCarb, GeoCarb, GOSAT-GW, CO2M).</p>

A. Lichtenberger, C. Meyer, Torben Schreiber et al.

In March of 2021, the Berlin-based company cmp continued geophysical prospection works at the ancient city of Artashat-Artaxata (Ararat Province, Armenia). The city was founded by Artashes-Artaxias I in the early 2nd century BC and served as his capital. First magnetic measurements were conducted by the Eastern Atlas company in September 2018. In 2021, during the 5-day survey a total surface of approximately 19.5 ha was investigated by use of the LEA MAX magnetic gradiometer array. This system was configured with seven fluxgate gradiometer probes, similar to the system used in the first survey of 2018. The investigated areas of the Eastern Lower City of Artaxata, located to the south of the investigated field of 2018, had good surface conditions with a moderate amount of sources causing disturbance. However, the general level of the magnetic gradient values measured was significantly lower compared to the 2018 data. Despite the lower magnetic field intensity, a continuation of linear structures towards the south was observed. These lines, most likely reflecting streets and pathways, criss-cross the central part of the Eastern Lower City in a NW–SE and NE–SW direction and exhibit partly positive, partly negative magnetic anomalies. Attached to them, some isolated spots with building remains were identified. The negative linear anomalies point to remains of limestone foundations, as detected in the northern part of the Lower City. The low magnetic intensity and fragmentation of the observed structures are most likely due to severe destruction of the ancient layers by 20th-century earthworks for agricultural purposes. Moreover, the southern part of the surveyed area was affected by major changes caused by modern quarries at Hills XI and XII. In general, the results of the two magnetic prospection campaigns greatly aid our understanding of the archaeological situation in the area of the Eastern Lower City of Artaxata, justifying further investigations that will surely contribute to greater contextualization of the identified archaeological structures. The full data sets are also published in open access on Zenodo.

C. C. Womack, C. C. Womack, S. S. Brown et al.

<p>We describe the design and performance of a lightweight broadband cavity-enhanced spectrometer for measurement of NO<span class="inline-formula">₂</span> on uncrewed aerial vehicles and light aircraft. The instrument uses a light-emitting diode (LED) centered at 457 nm, high-finesse mirrors (reflectivity <span class="inline-formula">=0.999963</span> at 450 nm), and a grating spectrometer to determine optical extinction coefficients between 430 and 476 nm, which are fit with custom spectral fitting software and published absorption cross sections. The instrument weighs 3.05 kg and has a power consumption of less than 35 W at 25 <span class="inline-formula">^∘</span>C. A ground calibration unit provides helium and zero air flows to periodically determine the reflectivity of the cavity mirrors using known Rayleigh scattering cross sections. The precision (1<span class="inline-formula"><i>σ</i></span>) for laboratory measurements is 43 ppt NO<span class="inline-formula">₂</span> in 1 s and 7 ppt NO<span class="inline-formula">₂</span> in 30 s. Measurement of air with known NO<span class="inline-formula">₂</span> mixing ratios in the range of 0–70 ppb agreed with the known values within 0.3 % (slope <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>=</mo><mn mathvariant="normal">0.997</mn><mo>±</mo><mn mathvariant="normal">0.007</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="78pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="070c85d9bb34c1e2574f428ab72c4964"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-15-6643-2022-ie00001.svg" width="78pt" height="10pt" src="amt-15-6643-2022-ie00001.png"/></svg:svg></span></span>; <span class="inline-formula"><i>r</i>²=0.99983</span>). We demonstrate instrument performance using vertical profiles of the NO<span class="inline-formula">₂</span> mixing ratio acquired on board an uncrewed aerial vehicle between 0 and 110 m above ground level in Boulder, Colorado.</p>

S. Noël, M. Reuter, M. Buchwitz et al.

<p>We show new results from an updated version of the Fast atmOspheric traCe gAs retrievaL (FOCAL) retrieval method applied to measurements of the Greenhouse gases Observing SATellite (GOSAT) and its successor GOSAT-2. FOCAL was originally developed for estimating the total column carbon dioxide mixing ratio (<span class="inline-formula">XCO₂</span>) from spectral measurements made by the Orbiting Carbon Observatory-2 (OCO-2). However, depending on the available spectral windows, FOCAL also successfully retrieves total column amounts for other atmospheric species and their uncertainties within one single retrieval. The main focus of the current paper is on methane (<span class="inline-formula">XCH₄</span>; full-physics and proxy product), water vapour (<span class="inline-formula">XH₂O</span>) and the relative ratio of semi-heavy water (<span class="inline-formula">HDO</span>) to water vapour (<span class="inline-formula"><i>δ</i>D</span>). Due to the extended spectral range of GOSAT-2, it is also possible to derive information on carbon monoxide (<span class="inline-formula">XCO</span>) and nitrous oxide (<span class="inline-formula">XN₂O</span>) for which we also show first results. We also present an update on <span class="inline-formula">XCO₂</span> from both instruments.</p> <p>For <span class="inline-formula">XCO₂</span>, the new FOCAL retrieval (v3.0) significantly increases the number of valid data compared with the previous FOCAL retrieval version (v1) by 50 % for GOSAT and about a factor of 2 for GOSAT-2 due to relaxed pre-screening and improved post-processing. All v3.0 FOCAL data products show reasonable spatial distribution and temporal variations. Comparisons with the Total Carbon Column Observing Network (TCCON) result in station-to-station biases which are generally in line with the reported TCCON uncertainties.</p> <p>With this updated version of the GOSAT-2 FOCAL data, we provide a first total column average <span class="inline-formula">XN₂O</span> product. Global <span class="inline-formula">XN₂O</span> maps show a gradient from the tropics to higher latitudes on the order of 15 <span class="inline-formula">ppb</span>, which can be explained by variations in tropopause height. The new GOSAT-2 <span class="inline-formula">XN₂O</span> product compares well with TCCON. Its station-to-station variability is lower than 2 <span class="inline-formula">ppb</span>, which is about the magnitude of the typical <span class="inline-formula">N₂O</span> variations close to the surface. However, both GOSAT-2 and TCCON measurements show that the seasonal variations in the total column average <span class="inline-formula">XN₂O</span> are on the order of 8 <span class="inline-formula">ppb</span> peak-to-peak, which can be easily resolved by the GOSAT-2 FOCAL data. Noting that only few <span class="inline-formula">XN₂O</span> measurements from satellites exist so far, the GOSAT-2 FOCAL product will be a valuable contribution in this context.</p>

Bruna Zakharia Hoch, A. Diambra, E. Ibraim et al.

C. Nwaiwu, E. O. Mezie

The continual depletion of valuable earth resources due to structural developments have been of much concern in the quest for sustainability, thus, the importance of soil compaction cannot be overemphasized. The world population is increasing every day and there is constant need of more infrastructures such as roads, runways, dams, buildings, jetties, railways etc. All these structures are built on soils which sometimes do not have adequate bearing capacity to resist the loads coming on them. In Nigeria, the common soils used for construction work which are laterite are sometimes found unsuitable in its natural state for intended use. Thus, there is the need for soil improvement of which compaction is among the commonest and the cheapest. Laterites are described as highly weathered and altered residual soils formed by insitu weathering and decomposition of parent rocks under tropical and subtropical climatic conditions (Aginam et al., 2014). The increasing use of this soil is linked to its availability, cheapness and amenability to compaction. Compaction of lateritic soils like other soils, increases the bearing capacity of the soils. It also decreases the amount of undesirable settlement of structures constructed over such soils and increases the stability of slopes of embankments (Ratnam & Prasad, 2019). The strength of foundations largely depend on compaction control which is based on finding the maximum dry unit weight (MDUW) corresponding to an optimum moisture content (OMC) at a given compaction energy. Laboratory compaction is usually done in Nigeria with British Standard Light (BSL) (equivalent of standard Proctor method), West African Standard (WAS), and British Standard Heavy (BSH) (equivalent of modified Proctor method). These methods are laborious, time-consuming and material-consuming (Jayan & Sankar, 2015). The shortcomings outlined above together with proof by some earlier authors Ring et al. (1962), Ramiah et al. (1970), Benson et al. (1998) and most recently Anjita et al. (2017) that soil type, its grain size distribution, index properties, and specific gravity influence the MDUW and OMC of soils led researchers to develop empirical relationships between MDUW/OMC and index properties of soils. Such index properties as liquid limit (LL), plastic limit (PL), plasticity index (PI), fines content (FC), sand content (SdC) etc. have previously been used. Abstract Laboratory compaction of soils is an important aspect in the selection of materials for earthwork construction. Owing to time constraints and concern for depleting resources, it becomes imperative that empirical relationships would be developed to predict compaction parameters, maximum dry unit weight (MDUW) and optimum moisture content (OMC) from easily measured index properties. The aim of this note is to develop empirical relationships between MDUW /OMC and logarithm of compaction energy (E)/fines content: sand content ratio (FC/SdC) for some lateritic soils. Index property tests were carried out on twenty (20) lateritic soils to classify them and obtain the FC/SdC. The soils were compacted at three compaction energies; British Standard Light (BSL), West African Standard (WAS) and British Standard Heavy (BSH). Two models were developed from relationships based on slopes and intercepts derived from MDUW/OMC versus log E plots; one model employs ‘FC/SdC’ and one compactive effort (BSL) while the other model employs only ‘FC/SdC’. The models were validated for robustness with soils used in the development of the models and six (6) other soils not used to develop the models. For the prediction of BSH, the model employing FC/SdC and one compactive effort showed typical errors of ±0.63 kN/m3 and ±0.76% for MDUW and OMC respectively. The model employing only FC/SdC showed typical errors of ±0.4 kN/m3 and ±0.83% for MDUW and OMC respectively. The typical errors are within allowed variations for projects and standards for MDUW and OMC, thus the models are quite robust.

L. Chebanov, T. Chebanov, V. Cheban

Problem statement. The beginning of the production of vegetables in protected soil on an industrial basis in Ukraine was marked by the construction in the 80s of the last century of greenhouses from the structures of the Antratsyt Luhansk region prefabricated greenhouse plant. A new impetus to the development of greenhouse vegetable growing was provided by the commissioning of energy-saving modern winter greenhouses built in the period from 2005 to 2015. Greenhouse vegetable growing is not standing still, but is actively expanding around the world. Further development of this area is possible with the introduction of new technologies for construction and operation of greenhouses, as well as their design solutions. The development of greenhouse vegetable growing is an important economic task. The design and technological features of modern greenhouses of the fifth generation of the semi-closed type are shown, which allow to provide high yields at lower consumption of material resources. A study of the complexity of the construction of greenhouses, identified low-mechanized, manual processes. The purpose of the article is to show ways to improve the design and technological parameters of modern greenhouses. In order to ensure energy savings and increase yields. Results. The analysis of normative documents on design and construction of greenhouses is performed. It is shown that greenhouses, the so-called "semi-closed type", allow to obtain high vegetable yields and energy savings. The most mechanized processes for the construction of greenhouses are earthworks and foundations. Much of the manual labor takes place during the installation of the metal frame, glazing and heating systems. Scientific novelty and practical significance. For the first time the value of labor intensity and duration during the construction of greenhouses was obtained, their dependences on the main factors influencing the performance of construction and installation works were established. This allows at the stage of development of design and technological documentation to determine rational ways of performing work.

P. Hryhorovskyi, V. Oryshchenko, A. Tugay

The practice of construction in the conditions of compacted urban development shows that the construction work is likely to lead to a number of dangerous events, which are caused by additional loads on the structures of nearby facilities. The probability, nature, rate of development of undesirable processes and the degree of their danger depends on many factors that will be discussed in the article. Each building, structure or individual structure has a functional purpose, is operated under certain conditions and must meet safety requirements, ie the requirements of preventing accidents and collapses of the building as a whole or its components that may pose a danger to health and human life, or harm the environment and cause other emergencies. Significant experience has been gained in the reliability of buildings and structures in terms of determining the indicators of reliable and trouble-free operation of construction sites under normal operating conditions, ie work in the design mode. However, the vast majority of facilities in real operating conditions under the influence of various unforeseen and uncertain factors of influence, changing the design boundary conditions creates a direct risk of destruction. Monitoring is one of the main ways to prevent and make the necessary decisions in a timely manner to ensure the integrity of buildings and structures in compacted buildings in cases where new construction has a negative impact on these facilities. According to the research results, it is established that the main factors that determine the compacted conditions in the area of the pit and earthworks are the distance from the pit to the adjacent buildings and roads; soil base properties; the depth of the pit. The main reasons for the deformation of existing buildings during the new construction next to them, which is primarily the installation of ditches, is the increase in stresses in the base under the foundations of the surrounding buildings. The foundations of buildings work together with the soil base, and the development of their excessive deformations, uneven sediments and rolls leads to the destruction or further reduction of the serviceability of the responsible structural elements of the facilities in operation. The article presents the main compensatory measures for the protection of adjacent buildings during new construction.

V. Ulyanov

Purpose. The research is aimed to obtain some missing data on the morphology of river sands within the city, in particular, reliable quantitative indicators that can be used in the calculation of soil bases. Methodology. According to the experimental-analytical method, a complex soil morphology was used, which takes into account the shape and nature of the grain surface in the entire sand volume studied. Morphological assessment was carried out not only for individual sand particles, but also for the entire volume of the soil studied, due to this an important factor in the formation of the shape and nature of the sand grain surface is the mineral composition of sand. For the most of the studied sands, quartz was the predominant mineral. In further studies, it is planned to study the Dnipro River sands of deeper horizons, which would make it possible to obtain data on the formation of contacts between sand grains, which can be lamellar or other shapes. Findings. This paper presents the results of determining morphological indicator, as well as studying the shape and nature of the surface of alluvial sand grains of the 1st floodplain terrace of the Dnieper River valley in the area of Monastyrskyi Island in the central part of the city. The results of similar works on the study of a number of genetic types of Quaternary sands of various genesis in the Dnieper River valley were also analyzed. Due to this analysis, data were obtained on the morphology of monomineral oligomictic alluvial sands, the shape and nature of the alluvium sand grains surface. Originality. For the first time for the central region of the city, some basic morphological characteristics of river Quaternary sands of the Dnieper River valley were obtained. It is also possible to note the tendency of decrease of morphology indicator in river sands of the Dnieper valley from sources to the mouth. Practical value. With all confidence, the results of the studies carried out can be implemented in the sandy soils of the foundations of buildings and structures of the city, as well as to artificial earthworks, in particular, alluvial massifs.

J. Mendonca, R. Nassar, C. W. O'Dell et al.

<p>Satellite retrievals of <span class="inline-formula">XCO₂</span> at northern high latitudes currently have sparser coverage and lower data quality than most other regions of the world. We use a neural network (NN) to filter Orbiting Carbon Observatory 2 (OCO-2) B10 bias-corrected <span class="inline-formula">XCO₂</span> retrievals and compare the quality of the filtered data to the quality of the data filtered with the standard B10 quality control filter. To assess the performance of the NN filter, we use Total Carbon Column Observing Network (TCCON) data at selected northern high latitude sites as a truth proxy. We found that the NN filter decreases the overall bias by 0.25 <span class="inline-formula">ppm</span> (<span class="inline-formula">∼</span> 50 %), improves the precision by 0.18 <span class="inline-formula">ppm</span> (<span class="inline-formula">∼</span> 12 %), and increases the throughput by 16 % at these sites when compared to the standard B10 quality control filter. Most of the increased throughput was due to an increase in throughput during the spring, fall, and winter seasons. There was a decrease in throughput during the summer, but as a result the bias and precision were improved during the summer months. The main drawback of using the NN filter is that it lets through fewer retrievals at the highest-latitude Arctic TCCON sites compared to the B10 quality control filter, but the lower throughput improves the bias and precision.</p>

X. Zhang, X. Zhang, Y. Yin et al.

<p>Lightning serves as the dominant source of nitrogen oxides (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">NO</mi><mi>x</mi></msub><mo>=</mo><mi mathvariant="normal">NO</mi><mo>+</mo><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="80pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="a1a9a6720bb1e0b9b83931d45ed6d7c4"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-13-1709-2020-ie00001.svg" width="80pt" height="13pt" src="amt-13-1709-2020-ie00001.png"/></svg:svg></span></span>) in the upper troposphere (UT), with a strong impact on ozone chemistry and the hydroxyl radical production. However, the production efficiency (PE) of lightning nitrogen oxides (L<span class="inline-formula">NO_<i>x</i></span>) is still quite uncertain (32–1100&thinsp;mol&thinsp;NO per flash). Satellite measurements are a powerful tool to estimate L<span class="inline-formula">NO_<i>x</i></span> directly compared to conventional platforms. To apply satellite data in both clean and polluted regions, a new algorithm for calculating L<span class="inline-formula">NO_<i>x</i></span> has been developed that uses the Berkeley High-Resolution (BEHR) v3.0B <span class="inline-formula">NO₂</span> retrieval algorithm and the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). L<span class="inline-formula">NO_<i>x</i></span> PE over the continental US is estimated using the <span class="inline-formula">NO₂</span> product of the Ozone Monitoring Instrument (OMI) data and the Earth Networks Total Lightning Network (ENTLN) data. Focusing on the summer season during 2014, we find that the lightning <span class="inline-formula">NO₂</span> (L<span class="inline-formula">NO₂</span>) PE is <span class="inline-formula">32±15</span>&thinsp;mol&thinsp;<span class="inline-formula">NO₂</span> per flash and <span class="inline-formula">6±3</span>&thinsp;mol&thinsp;<span class="inline-formula">NO₂</span> per stroke while L<span class="inline-formula">NO_<i>x</i></span> PE is <span class="inline-formula">90±50</span>&thinsp;mol&thinsp;<span class="inline-formula">NO_<i>x</i></span> per flash and <span class="inline-formula">17±10</span>&thinsp;mol&thinsp;<span class="inline-formula">NO_<i>x</i></span> per stroke. Results reveal that our method reduces the sensitivity to the background <span class="inline-formula">NO₂</span> and includes much of the below-cloud L<span class="inline-formula">NO₂</span>. As the L<span class="inline-formula">NO_<i>x</i></span> parameterization varies in studies, the sensitivity of our calculations to the setting of the amount of lightning NO (LNO) is evaluated. Careful consideration of the ratio of L<span class="inline-formula">NO₂</span> to <span class="inline-formula">NO₂</span> is also needed, given its large influence on the estimation of L<span class="inline-formula">NO₂</span> PE.</p>

Chadwick Allen

For thousands of years, mounds, embankments, and other earthworks were dreamed, planned, and built; occupied, used, and maintained; abandoned, reoccupied, and reused; redreamed, rebuilt, and repurposed by Indigenous peoples living and traveling along the rivers and other waterways that connect the eastern half of the North American continent into a vast network – from what is now Louisiana in the south to what is now Ontario in the north. During that long tenure, mounds, embankments, and other earthworks were also studied, contemplated, and discussed by Indigenous intellectuals, by political and spiritual leaders, by builders, users, and ordinary citizens. Not only empirical research but theoretical reflection was necessarily grounded in Indigenous languages and communities, conducted through Indigenous methodologies. For the past 200 years, however, energy devoted to understanding the complexity of these built environments and their multiple potential meanings and uses has been organised by predominantly non-Native archaeologists, anthropologists, and historians, both amateur and professional, and within predominantly non-Native languages, epistemologies, and systems of ethics. In this way, like so much of Indigenous life and culture, earthworks research has been disconnected from the foundations of Indigenous inquiry. The majority of this non-Native research has restricted its investigations to questions about the physical construction of earthworks within specific chronologies (these researchers repeatedly ask not only who built the mounds, but how they were built, when, and whether within briefer or longer periods of time) and to questions about the siting of earthworks within specific geographies (where they were built, but also why they were built in certain ways at certain times and in certain locations). The organisation and control of this work by non-Native researchers and institutions, moreover, has been – and continues to be – bolstered by the colonial dislocations and the often forced relocations of the descendants of the Indigenous peoples who built the mounds. Although the scholarly fields of archaeology, anthropology, and history have begun to expand the scope of their interests and the range of their interlocutors, including an increased attention to consulting with Indigenous communities, relatively little of this research has been devoted to understanding – or imagining – the effects of earthworks on people: those who came together to plan and build individual mounds or embankments or to construct multi-structure complexes and expansive cities; those who lived among earthworks permanently or seasonally; those who visited sites, centres, and cities for trade or special events; those who embarked on sacred 16