Dry Layer Research Articles

Integrated Plastic Microfluidic Device for Heavy Metal Ion Detection.

The presence of heavy metal ions in soil, air and water constitutes an important global environmental threat, as these ions accumulate throughout the food chain, contributing to the rise of chronic diseases, including, amongst others, cancer and kidney failure. To date, many efforts have been made for their detection, but there is still a need for the development of sensitive, low-cost, and portable devices able to conduct on-site detection of heavy metal ions. In this work, we combine microfluidic technology and electrochemical sensing in a plastic chip for the selective detection of heavy metal ions utilizing DNAzymes immobilized in between platinum nanoparticles (PtNPs), demonstrating a reliable portable solution for water pollution monitoring. For the realization of the microfluidic-based heavy metal ion detection device, a fast and easy-to-implement fabrication method based on the photolithography of dry photosensitive layers is proposed. As a proof of concept, we demonstrate the detection of Pb2+ ions using the prototype microfluidic device.

An adaptive ensemble learning by opposite multiverse optimizer and its application in fluid identification for unconventional oil reservoirs

Unconventional reservoirs are rich in petroleum resources. Reservoir fluid property identification for these reservoirs is an essential process in unconventional oil reservoir evaluation methods, which is significant for enhancing the reservoir recovery ratio and economic efficiency. However, due to the mutual interference of several factors, identifying the properties of oil and water using traditional reservoir fluid identification methods or a single predictive model for unconventional oil reservoirs is inadequate in accuracy. In this paper, we propose a new ensemble learning model that combines 12 base learners using the multiverse optimizer to improve the accuracy of reservoir fluid identification for unconventional reservoirs. The experimental results show that the overall classification accuracy of the adaptive ensemble learning by opposite multiverse optimizer (AIL-OMO) is 0.85. Compared with six conventional reservoir fluid identification models, AIL-OMO achieved high accuracy on classifying dry layers, oil–water layers, and oil layers, with accuracy rates of 94.33%, 90.46%, and 90.66%. For each model, the identification of the water layer is not accurate enough, which may be due to the classification confusion caused by noise interference in the logging curves of the water layer in unconventional reservoirs.

Farmers’ first rain: investigating dry season rainfall characteristics in the Peruvian Andes

In the Peruvian Andes, the first light rainfalls towards the end of the dry season in August-September are known as pushpa. Softening soils and improving sowing conditions, these rains are crucial for planting dates and agricultural planning. Yet pushpa remains to date unexplored in the literature. This study uses observations and convection-permitting model simulations to describe the characteristics of pushpa in the Rio Santa valley (Peru). Comparing an observed pushpa case in August 2018 with a dry and wet event of the same season, we find pushpa to coincide with upper-level westerly winds that are otherwise characteristic for dry periods. These conditions impose an upper-level dry layer that favours small-scale, vertically-capped convection, explaining the low rainfall intensities that are reportedly typical for pushpa. Climatologically, we find 83% of pushpa-type events to occur under westerly winds, dominating in August, when 60% of the modelled spatial rainfall extent is linked to pushpa. Larger, more intense deep-convective events gradually increase alongside more easterly winds in September, causing the relative pushpa cloud coverage to drop to ̃20%. We note high inter-annual and -decadal variability in this balance between pushpa and intense convective rainfall types, with the spatial extent of pushpa rainfall being twice as high during 2000-2009 than for the 2010-2018 decade over the key sowing period. This result may explain farmers’ perception in the Rio Santa valley, who recently reported increased challenges due to delayed but more intense pushpa rains before the rainy season start. We thus conclude that the sowing and germination season is crucially affected by the balance of pushpa-type and deep-convective rain, resulting in a higher probability for late first rains to be more intense.

Creation of a methodology for determining the moisture diffusion coefficient within vacuum drying of fruits

As the drying zone deepens, outer surface layer of the product does not have time to be moistened, due to a small amount of moisture coming from the inside. It becomes dry, its temperature rises. The intensity of moisture transfer from the inner layers of the product depends on many parameters, including a moisture diffusion coefficient. The study aim is to create a methodology for determining the moisture diffusion coefficient within vacuum drying of fruits, by taking into account cracks, channels and capillaries formed in the dry layer of the product through the resistance coefficient to evaporation. The work essence consists in the determining of the moisture diffusion coefficient as a driving force, a difference between water activity and air humidity, by considering the resistance coefficient to evaporation, characterizing the effect of hydrodynamic resistance of the dried dry layer of the product. This approach was used to determine the moisture diffusion coefficient during vacuum drying of the Baiterek apple sort and the Zhazdyk pear sort of Kazakhstani selection. It was established that in the first period of drying the moisture diffusion coefficient decreases on average from 24,4∙10‒7 m2/s to 13,2∙10‒7 m2/s. The critical humidity for pear is 37.4 %, and for apple 35.1 %. As result of the formation of dry layer on the surface and subsequent layers, the moisture diffusion coefficient gradually decreases. In the second drying period, the moisture diffusion coefficient decreases from 5,42∙10-8 m2/s to 2,12∙10‒8 m2/s. The work practical significance is related with the application of the obtained results in the determination of the optimal drying regime with maximum preservation of the product original quality. The proposed methodology can be used in the practice to study the moisture diffusion coefficient within vacuum drying of fruits, by considering the product properties and the hygroscopic parameters of the drying matter

Impact experiments on granular materials under low gravity: Effects of cohesive strength, internal friction, and porosity of particle layers on crater size

Impact craters on the surface of asteroids provide information about their surface properties and evolutionary processes. Investigating how crater size depends on these physical properties is important for establishing a crater-size scaling law. We conducted high-velocity impact experiments at 1 G and at simulated low gravity on dry particle layers with different physical properties. The crater diameter was larger for targets with smaller internal friction. Also, for similar internal friction, the crater diameter was larger for targets with lower porosity. The crater diameter for targets with particle diameters of several hundred micrometers was proportional to the gravitational acceleration to the power of −0.16 to −0.18. However, the crater diameters for targets with particle sizes of ∼40 μm showed little or no difference between 1 G and low gravity. Although the results for targets with particle sizes of ∼40 μm at 1 G showed a relationship in the gravity regime, the results under low gravity deviated from this tendency. We obtained the condition for the transition between the gravity- and strength-dominated regimes: the ratio of the cohesion Ycoh to the term ρtgD, or the ratio of the effective strength YEFF to ρtgD, where ρt, g, and D are the target bulk density, gravitational acceleration, and crater diameter, respectively. The values of Ycoh/ρtgD and YEFF/ρtgD for targets with particle sizes of ∼40 μm were 0.22–0.27 and 0.11–0.60, respectively. This study provides basic experimental data for comparison with numerical simulations.

Validation of a Contrail Life-Cycle Model in Central Europe

In an industry beset by economic and environmental crises, air transport, the safest and most efficient long-haul mode of transport, is confronted daily with multi-criteria challenges to improve its environmental performance. The formation of contrails through the emission of water vapor and condensation nuclei in what are actually dry and clean atmospheric layers represents one of the most unpredictable, or measurable, environmental impacts of air traffic. Following the bottom-up principle to evaluate individual contrails in order to derive recommendations for trajectory optimization, not only the calculation of the radiative forcing of the contrails but also the modeling of their life cycle is burdened with uncertainties. In former studies for modeling the microphysical life cycle of contrails based on a 3-D Gaussian plume model, the atmospheric conditions, specifically the turbulence, were often unknown and had to be considered as a free input variable. In this study, an innovative photographic method for identifying and tracking contrails in Central Europe, connected with database access to Automatic Dependent Surveillance—Broadcast (ADS-B) data (i.e., aircraft type, speed, altitude, track, etc.), and a combination of measured and modeled weather data are used to validate the contrail life-cycle model (i.e., the assumed Gaussian plume behavior). We found that it is challenging to model the position of ice-supersaturated layers with global forecast models, but they have the most significant impact on the contrail lifetime. On average, the contrail’s lifespan could be modeled with an error margin of 10%. Sometimes, we slightly underestimated the lifetime. With the validated and plausible contrail life-cycle model, we can apply the climate effectiveness of individual contrails with higher certainty in trajectory optimization and compare it, for example, with economic aspects such as delay costs or fuel costs.

The relationship between vegetation and soil moisture reveals the vegetation carrying capacity threshold—A case study of a Haloxylon ammodendron plantation in the Alxa desert, China

Afforestation is an important and effective way to curb wind-sand hazards in the Alxa Desert. However, over-afforestation makes soil drying occur frequently. The formation of a soil drying layer is seriously restricting the effectiveness of vegetation construction and regional ecological stability. To clarify the process of soil desiccation inHaloxylon ammodendronplantations and determine the suitable planting years, a typicalH. ammodendronplantation in this area was selected as the research object, and the soil moisture variation characteristics of this sand-fixing vegetation region with vegetation age were analyzed. The analysis results on soil water supply, consumption, and balance showed that the soil water storage in 0–400 cm soil layer ofH. ammodendronplantation varies significantly in different ages. The soil water storage in 0–11 years old was the largest, and the soil water supply was greater than the soil water consumption. The soil water storage in profile increased with the increase of precipitation, the soil water storage ofH. ammodendronat 11–22 years old increased first and then decreased with precipitation, and the inflexion existed in 16.5 years old. The soil water consumption ofH. ammodendronplantation at 22–46 years old was greater than that of soil water supplement, and the soil moisture appeared negative balance continuously. Therefore, to prevent further deterioration of soil moisture ecological environment in theH. ammodendronplantation and to promote the sustainable development of afforestation in desert areas, thinning measures are suggested when the growth period reaches 16.5 years. The research results could provide scientific basis for afforestation and soil dry layer regulation in the Alxa desert.

An Adhesive/Anti-Adhesive Janus Tissue Patch for Efficient Closure of Bleeding Tissue with Inhibited Postoperative Adhesion.

Most of the current bioadhesives cannot perform well on bleeding tissues while postoperative adhesion is a general but serious clinical issue. Here, a three-layer biodegradable Janus tissue patch (J-TP) that is able to simultaneously enable efficient closure of bleeding wounds with significantly promoted clotting ability and suppressed postoperative adhesion of tissues is reported. A dry adhesive hydrogel bottom layer of the J-TP can form rapid (within 15 s) and strong (tensile strength up to 98kPa) adhesion to bleeding/wet tissues with high bursting pressure (about 312.5mmHg on a sealed porcine skin) through hydrogen binding and covalent conjugation between the carboxyl & N-hydroxy succinimide (NHS) groups of hydrogel and the primary amine groups of tissues, while the phosphonic motifs can significantly reduce blood loss (by 81% on a rat bleeding liver model) of bleeding wounds. A thin polylactic acid (PLA) middle layer can improve the tensile strength (by 132%) of the J-TP in wet conditions while the grafted zwitterionic polymers can effectively prevent postoperative tissue adhesion and inflammatory reaction. This J-TP may be a promising tissue patch to assist the clinical treatment of injured bleeding tissues with inhibited postoperative adhesion.

Biogeochemistry of low‐ and high‐centered ice‐wedge polygons in wetlands in Svalbard

AbstractArctic wetlands are a globally significant store of soil organic carbon. They are often characterized by ice‐wedge polygons, which are diagnostic of lowland permafrost, and which greatly influence wetland hydrology and biogeochemistry during summer. The degradation of ice‐wedge polygons, which can occur in response to climate change or local disturbance, has poorly understood consequences for biogeochemical processes. We therefore used geochemical analyses from the active layer and top permafrost to identify and compare the dominant biogeochemical processes in high‐centered (degraded) and low‐centered (pristine) polygons situated in the raised beach sediments and valley‐infill sediments of Adventdalen, Central Svalbard. We found similar organic‐rich sediments in both cases (up to 38 dry wt.%), but while low‐centered polygons were water‐saturated, their high‐centered counterparts had a relatively dry active layer. Consequently, low‐centered polygons showed evidence of iron and sulfate reduction leading to the precipitation of pyrite and siderite, whilst the high‐centered polygons demonstrated more oxidizing conditions, with decreased iron oxidation and low preservation of iron and sulfate reduction products in the sediments. This study thus demonstrates the profound effect of ice‐wedge polygon degradation on the redox chemistry of the host sediment and porewater, namely more oxidizing conditions, a decrease in iron reduction, and a decrease in the preservation of iron and sulfate reduction products.

Effect of the Freezing Step on Primary Drying Experiments and Simulation of Lyophilization Processes

Lyophilization is a widely used preservation method for thermosensitive products. It consists of three process steps: freezing, primary and secondary drying. One of the major drawbacks is the long processing time. The main optimization effort was put into the primary drying phase since it is usually the longest phase. However, the freezing step is of immense importance for process efficiency and product quality. The lack of control during freezing comprises a challenge for process design and tech transfer. In this study, four different freezing steps (shelf-ramped freezing with and without holding step, precooled shelves and an ice fog method for controlled nucleation) are used and their impact on primary drying experiments and simulations is shown. Only the ice fog method is able to control the nucleation temperature leading to low dry layer resistances with low deviations. During the primary drying simulations, the control of the nucleation temperature drastically increases the precision and accuracy of the product temperature prediction. For optimal primary drying design and model predictive control, the nucleation temperature is strongly recommended to be controlled inside a Process Analytical Technology (PAT) concept to achieve reliable and reproducible process conditions.

Environmental Parameter Analysis during the Extreme Damaging Gale that Hit the East Coast of the Shandong Peninsula

In this study, sounding data were used to investigate the environmental parameters of the eastern Shandong coast. June was the month with the most extreme thunderstorm winds, according to the results. Several parameters, which can be referenced in daily forecasts and early warnings, are indicative of extreme thunderstorms and gales. Strong convective storms are often the cause of extreme gales. Usually, there must be moderate to strong vertical wind shear conditions. The wet layer does not need to be excessively thick, but there is a very distinct dry layer with strong entrainment potential in the middle layer.

2D Electrical Resistivity Imaging to delineate the exact boundary and true thickness of granular aquifers

Electrical resistivity imaging (ERI) is one of the best geophysical techniques for studying subsurface and groundwater aquifer investigations. In clastic sediments, determining the exact boundary between different layers on the inverse section of ERI is not an easy task due to gradual changes in resistivity between surrounding layers and the granular aquifers. Therefore, the main aim of the study is to indicate a more precise boundary of the granular aquifers (true thickness of aquifers) on the inverse section. Two different models were used: the field model and the laboratory model, in the field model, four different locations were selected. They are located in (Kalar, Chamchamal, Bazyan, and Piramagroon), within the Sulaymaniyah Governorate, NE Iraq. Two-dimensional (2D) electrical resistivity imaging was carried out along four profiles of 355 m length with a five-meter electrode spacing. The Wenner-Schlumberger array was used for recording the data. For the lab model, a laboratory geological model was constructed has length, height, and width equal to 192, 65, and 45 cm, respectively. Two synthetic profiles were carried out on this model, they have lengths of 190 cm with electrode spacing of 10 cm. The field results indicated that aquifers in clastic sediments on inverse sections always showed anomalies with apparent thicknesses larger than their true thicknesses, which were obtained from the geological column of the wells. In the four studied locations, aquifers' average true thickness is approximately 68.2% of the apparent thicknesses on the inverse sections. The result of the laboratory geological model also showed that the true thickness of the unsaturated gravel is approximately equal to 59.7% of the apparent thickness of the anomaly, which is formed by the dry gravel layer. Also, the true thickness of the saturated gravel is about 57.1% of the apparent thickness of the anomaly, which is formed by the saturated gravel layer. Moreover, the geological model showed that the higher resistivity layer (dry gravel) creates a narrower transitional resistivity zone between clay and gravel than saturated gravel of lower resistivity.

Modelling pyro-convection phenomenon during a mega-fire event in Portugal

The present study contributes to an increased understanding of pyro-convection phenomena by using a fire-atmosphere coupled simulation, and investigates in detail the large-scale meteorological conditions affecting Portugal during the occurrence of multiple mega-fires events on 15 October 2017. Two numerical simulations were performed using the MesoNH atmospheric model. The first simulation, was run for a large single domain (300 × 250 grid points) with a 15 km resolution. In the second one, the MesoNH was coupled to a fire propagation model (ForeFire) to study in detail the Quiaios's fire. To optimize both high resolution in the proximity of the fire region and computational efficiency, the simulation is set up using 3 nested domains (300 × 300 grid points) with horizontal resolution of 2000 m, 400 m, and 80 m respectively. The emission into the atmosphere of the heat and the water vapour fluxes caused by the evolving fire is managed by the ForeFire code. The fire spatio-temporal evolution is based on an assigned map, which follows what reported by public authorities. At the large scale, the simulation shows the evolution of the hurricane Ophelia, pointing out the influence of south/southwest winds on the rapid spread of active fires, as well as the subtropical moisture transport toward mainland Portugal in the early evening, when violent pyro-convective activity was observed in Central Portugal. The coupled simulation allowed to reproduce the formation of a PyroCu cloud inside the smoke plume. The convective updraughts caused by the fire led to the vertical transport of water vapour to higher levels and enhanced the development of a high-based cloud over a dry atmospheric layer within the smoke plume.

The surface bearing capacity of a strong granular layer on weaker sand

Stronger granular layers are often placed as working platforms over weaker sand subgrade. The design of a working platform involves the calculation of a two-layer bearing capacity under rectangular loading. Existing design methods are either overly simplified, based on infinitely long strip loads and validated by a small number of small-scale 1g model tests, or rely on numerous or empirically derived charts that are difficult to use or implement into design software. In this paper a new and highly practical design method is proposed in which the bearing capacity is determined simply from the shear strengths and unit weights of the two soil layers. The method was derived from extensive finite-element analysis and finite-element limit analysis (FELA) parametric studies in both plane strain and axisymmetric geometries. It was validated against published physical model tests, other FELA analyses and existing design methods. It can be applied to all rectangular shape ratios with dry and saturated layers.

Groundwater Investigation Using Electrical Resistivity Method at the Edati Hill, Northern Bida Basin, Nigeria

Electrical resistivity investigation was conducted using the Wenner-α and Schlumberger configuration around the Edati hill of the northern Bida Basin to understand the groundwater potential and electrical characteristics of the subsurface lithology. Eight electrical resistivity tomography (ERT) lines and thirty-one electrical resistivity sounding (VES) points were occupied in the study. The ERT inversion results revealed two to three layers within the studied depth, as follows; (a) a clayey to silty layer with varying resistivity (49.1Ωm to 11035Ωm) and thickness, representing the top soil; (b) a very thick claystone layer with resistivity between 383 Ωm and 3261 Ωm, corresponding to non-porous, non-aquiferous ferruginized claystone and sandstone layer, except in the northwest where the sand is non-ferruginized and aquiferous; (c) an intermediate to high resistivity (104 Ωm to 5999 Ωm) layer which forms the main aquifer in the northwest with thickness between 15 and 40 meters. The result of the VES revealed four to five geoelectrical layers; a variable resistivity dry surface layer; increasingly high resistivity second to fifth ferruginized clay layer, with very thin aquifer at depth beyond 150 meters. The second and third layers in the northwest are low resistivity aquiferous sandstones. Sustainable borehole drilling has been determined to be in the northwest of the study area at depth of 70 meters.

Optimal clipping intensity for balancing soil erosion control and runoff production on revegetated slopes

Clipping management by reducing the above-ground parts of grassland has been gradually introduced to offset some of the additional issues caused by large-scale vegetation restoration, such as the formation of a dry soil layer, approaching the limits of watershed water resources, and reducing the sustainability of vegetation. Therefore, there is a scientific and practical need to evaluate the effectiveness of clipping management on runoff and erosion processes to ensure a balance between erosion control, surface water supply, and vegetation sustainability. In this study, simulated rainfall experiments with four levels of clipping intensities (no clipping, light clipping, heavy clipping, and clear clipping) were conducted to explore the mechanism of runoff and soil loss response under three rainfall intensities (i.e., 60, 90, and 120 mm·h−1) and three slope gradients (i.e., 18, 36, and 58 %) using structural equation modeling and variation partitioning. The results showed that the runoff depth increased by 42 %, 119 %, and 299 %, respectively, and the soil loss increased by 76 %, 80 %, and 470 %, respectively, in the light, heavy, and clear clipping treatments compared with the no clipping treatment, indicating that the increase in the percentage of runoff production and soil loss was not synchronized. According to the optimizing results of response surface method, the recommended vegetation cover after clipping was 23 % − 48 %, and the slope gradient of clipped vegetation should not exceed 36 %, which increased surface runoff while limiting soil erosion within an acceptable range. Runoff production and soil loss were primarily determined by rainfall intensity, followed by clipping intensity and slope gradient. Increasing rainfall intensity and slope gradient increased the effect of clipping on soil loss. Therefore, local rainfall and topography need to be considered in the application of clipping management. This study provides valuable insights into the use of clipping treatment as a sustainable management strategy for mitigating soil erosion and conserving surface water resources, and has important implications for developing restoration plans to promote sustainability in semi-arid ecosystems.

Soil water depletion patterns in rainfed apple orchards and wheat fields.

Agricultural production in the Weibei rainfed highland, Northwest China, is challenged by severe drought and water shortages. While the land use pattern has shifted gradually from crop production to orchard farming in Weibei, little is known about the influence of fruit industry development on regional water resources and the rationality of planting orchards. Here, we characterized soil water depletion patterns in rainfed orchards and farmlands to evaluate the occurrence of soil desiccation under land use conversion from farmlands to orchards in Weibei. Soil moisture dynamics were monitored in the 0-150cm soil profiles of different aged Red Fuji apple orchards (young: 7 years, mature: 13 years, old: 22 years) and long-term cultivated winter wheat fields. We measured soil moisture content by oven-drying method in the middle of each month during the growing season of apple trees (March-September 2019). The over-depletion and depletion of soil water were analyzed to evaluate water stress and differential water depletion by distinct vegetation, respectively. The soil desiccation index was used to determine the occurrence of dry soil layers. Water stress was only observed at the 0-70-cm soil depths in the old orchards (mid-June) and farmlands (mid-May-mid-July). Water depletion took place at deeper depths for longer periods in the older orchards than in the younger orchards. Soil desiccation was absent in the young orchards, with mild desiccation at the 0-80-cm soil depths in the mature and old orchards in mid-June. The desiccation intensity was mild at the 0-60-cm soil depths in mid-April-mid-May, intense at the 0-150-cm soil depths in mid-June, and moderate at the 20-150-cm soil depths in mid-July. Results of this study demonstrate the mitigation of water stress and soil desiccation following conversion from wheat fields to apple orchards, which verifies the rationality of planting orchards in the rainfed highland area. Our findings provide strong support for developing a novel model of agro-industrial development, ecological construction, and sustainable economy in the vast arid and semi-arid areas of Northwest China.

Determination of dry soil layer and its soil heat flux distribution using actively heated distributed temperature sensing

A dry soil layer (DSL) of certain thickness is usually formed on the sandy soil surface during the soil water evaporation process, with the bottom boundary of DSL corresponding to the evaporating surface. As the water transfer mechanism in the DSL is different from that beneath the DSL, in the numerical analysis, it is essential to know such DSL in particular in terms of initial conditions. Moreover, the change in water transfer mechanism further leads to the change in energy transfer mechanism in the DSL, rendering the whole soil drying process more complex. To master the DSL distribution and its accompanying energy changes, a new method for determining the DSL and its soil heat flux (G) distribution based on the actively heated distributed temperature sensing (AH-DTS) technology is proposed. Through in-situ tests on the Loess Plateau in Yan'an, China, the DSL thickness and the G profiles in sandy soil are determined successfully. The results show that there is a DSL with a thickness of 0.25 m in the test site. The G in the DSL fluctuates with depth, and its value is significantly higher than that of the soil below the DSL, indicating that the G in the DSL provides energy for water evaporation at the evaporating surface. Note that the AH-DTS technology can realize multi-parameter measurement at the same time with high-resolution, which is effective and reliable for determining the DSL thickness and the G distribution. In practical applications, it is recommended that the DSL thickness be determined according to both soil temperature (T0) profile and volumetric water content (θ) profile. Moreover, it is suggested that a reasonable heating time-interval of at least two hours and the close contact between the AH-DTS sensor and the surrounding soil be guaranteed to ensure the accuracy of G profile determination.

Application of Geoelectric Technique in Groundwater Protection of Quaternary Aquifer in Wadi El Natrun, Egypt

Qualitative and quantitative interpretations of the accessible geoelectrical resistivity data were conducted in the area located to the west of Nile Delta on both sides of the Cairo-Alexandria desert road, between latitudes 30.190816° and 30.745892° N and longitudes 29.797607° and 30.702070° E, in the northern Western Desert of Egypt. The study area is covered by thick sedimentary exposures ranging from the Miocene to the Quaternary period. Geological factors such as lithology and geological structures significantly influence the groundwater in the study area. The Quaternary, Pliocene, and Miocene eras make up the majority of strata in the study region that require water.
 The study conducted twenty-three vertical electrical resistivity soundings using the Schlumberger array to define the shallow subsurface geological inferences and investigate the possibilities of finding underground water accumulations and its contamination with clay lenses. The examination of the obtained electric resistivity values revealed the segmentation of the examined section into five geoelectrical units with lateral variations in thicknesses, lithologies, and features. The five geoelectrical units had different compositions, with the first surface unit consisting of silt clay and relatively high resistivity sands and gravels that have been altered laterally. After the surface unit, resistivity ranges from relatively modest to high. Intercalation of sand and clay occurs in the second unit, followed by lenses of relatively medium-resistance coarse sand and clay in the third and fourth units, possibly forming an aquifer, and finally relatively low-resistance sand and clay in the fifth unit.
 Due to the haphazard drilling of hundreds of water wells, significant hydrogeological and environmental issues, such as soil salinization, water head decline, and groundwater salinity deterioration, have occurred. These issues have attracted significant expenditures in the field of land reclamation, both on small and large-scale projects. The study area is divided into five main geoelectrical layers observed along this cross area, as follows:
 The first surface geoelectrical layer (layer A) is characterized by relatively high resistivity ranging from 8.21 to 595.3 Ohm.m. The thickness of this layer varies from 2.1 to 8.86 m. This layer represents the dry surface cover of the area and consists of gravel, sand, and silt clay.
 The second geoelectrical layer (layer B) represents the dry layer lying above the water-bearing formation. It generally consists of sand and clay intercalation. The resistivity of this layer varies from 3.49 to 91.18 Ohm.m, and the thickness of this layer ranges from 17.13 to 38.3 m.
 The third geoelectrical layer (layer C1) is the water-bearing formation that generally consists of coarse sand and clay. The resistivity of this layer varies from 4.41 to 37.5 Ohm.m, and the thickness ranges from 10.38 to 54 m.
 The fourth geoelectric layer (layer C2) represents the lower part of the water-bearing formation. It consists of clayey sand and clay. The resistivity of this layer varies from 1.83 to 30.1 Ohm.m, and the thickness ranges from 17.78 to 31.35 m.
 The last geoelectric layer (layer D) represents the lower layer of investigation, consisting mainly of clay. The resistivity of this layer is generally low, varying within a narrow range of 26.7-39.8 Ohm.m.
 Finally the current study highlights the necessity of conducting in-depth geomorphological assessment studies before developing new reclamation projects, in addition to soil and water assessment.

Study of Relative Humidity Vertical Distribution Characteristics before Precipitation by Microwave Radiometer Data over Southeast China

We investigated the relative humidity (RH) vertical distribution characteristics before precipitation using microwave radiometer measurements over southeast China in 2021. The superposed epoch method is used to analyze the profile and vertical statistical characteristics and evolution of RH during precipitation events. There is a shallow, high-humidity area on the ground, with a thickness of about 0.1–0.2 Km, from 12 to 8 h before precipitation. An obvious dry layer appears in the lower layer near the ground 8–0 h before precipitation, with a thickness of about 1 km and humidity of less than 80%, which continues until the appearance of precipitation. The water vapor content in the air begins to accumulate and the humidity increases before the occurrence of LRs, MRs, and HRs, classified by total rainfall. The SDPs, MDPs, and LDPs, which are classified by precipitation duration, showed more obvious and significant characteristics of humidity increase. The statistical analysis of the 44 precipitation cases shows that the relative humidity on the ground and in the air increases significantly before precipitation, and the vertical distribution of the relative humidity and the increase in the water vapor content in the air have a more direct and obvious impact on the precipitation duration. The deep and high-humidity area of 2–4 km is conducive to maintaining the precipitation process for a long time.