Subsequent Rain Research Articles

Rapid response of stream dissolved phosphorus concentrations to wildfire smoke

Wildfires can produce large plumes of smoke that are transported across vast distances, altering nutrient cycling of undisturbed watersheds exposed downwind. To date, wildfire smoke influence on stream biogeochemical signatures remains an important knowledge gap. Here we evaluate the impacts of wildfire smoke on phosphorus (P) biogeochemical cycling in a temperate watershed in the Finger Lakes Region of Central New York located downwind from record setting Canadian forest fires during the summer of 2023. Daily sampling of stream and rainwaters was conducted over the 2 month smoke period, generating a robust geochemical dataset. Stream dissolved P showed high sensitivity to smoke events, attaining concentrations 2–3 × greater than the pre-smoke period. Subsequent rain events after smoke deposition were identified as a potentially important factor in magnitude and timing of dissolved P responses. These findings demonstrate the capacity for wildfire smoke to trigger rapid, observable changes to stream P chemistry.

Temporal and spatial shifts in the chemical composition of urban coastal rainwaters of Kuwait: The role of air mass trajectory and meteorological variables

The rainwater chemistry encompasses the signatures of geogenic and anthropogenic processes along the regional air mass movement apart from the local sources. The predominance of dust events and anthropogenic emissions in arid regions facilitate new particle formation. Further, rain events of different seasons depict moisture sources from diverse regions reflecting variation in the regional geochemistry with respect to seasons. Hence, to characterize the geochemical composition of rainwater, the study has focused on an integrated approach by considering regional transport, meteorological components and possible local sources. A total of 74 rainwater samples were collected from 27 rain events in 2018, 2019, and 2022, representing urban coastal areas of Kuwait predominantly of Ca-SO4-HCO3 type. The average pH and electrical conductivity of the rainwater were 7.18 and 140 μS/cm, respectively. The sea salt fractions calculated relative to Kuwait seawater ranged from 25.6 to >100 %, with higher values attributed to anthropogenic sources. Sea salt fraction, ion ratios, principal component analysis and factor scores revealed the terrestrial and anthropogenic sources apart from marine contributions. In addition, new particle formation and aerosols contributed to the rainwater chemistry involving SOx, NOx, and photochemical reactions during higher relative humidity and lesser wind speed. The HYSPLIT reflected that the moisture sources were largely from western regions of the study area, and those of December and January events had long-distance travel across the Azores high originating from northeast America. The trajectories of the November events are observed to originate from the Caspian/Black Sea region in the northeastern part of Kuwait with a relatively shorter distance of travel. The rainfall samples had higher ionic concentrations, and saturated with aragonite and calcite minerals in a few locations specifically after the dust events, while the subsequent rain events were less polluted.

Soil adsorption and transport of lead in the presence of perovskite solar cell-derived organic cations

Perovskite photovoltaics offer a highly efficient and low-cost solar energy harvesting technology. However, the presence of lead (Pb) cations in photovoltaic halide perovskite (HaPs) materials is concerning, and quantifying the environmental hazard of accidental Pb2+ leaching into the soil is crucial for assessing the sustainability of this technology. Pb2+ from inorganic salts was previously found to remain in the upper soil layers due to adsorption. However, Pb-HaPs contain additional organic and inorganic cations, and competitive cation adsorption may affect Pb2+ retention in soils. Therefore, we measured, analyzed by simulations and report the depths to which Pb2+ from HaPs penetrates into 3 types of agricultural soil. Most of the HaP-leached Pb2+ is found to be retained already in the first cm of the soil columns, and subsequent rain events do not induce Pb2+ penetration below the first few cm of soil surface. Surprisingly, organic co-cations from the dissolved HaP are found to enhance the Pb2+ adsorption capacity in clay-rich soil, compared to non-HaP-based Pb2+ sources. Our results imply that installation over soil types with improved Pb2+ adsorption, and removal of only the contaminated topsoil, are sufficient means to prevent ground water contamination by HaP-leached Pb2+.

Impact of Swine and Cattle Manure Treatment on the Microbial Composition and Resistome of Soil and Drainage Water.

Evaluating potential environmental and clinical impacts of industrial antibiotic use is critical in mitigating the spread of antimicrobial resistance. Using soil columns to simulate field application of swine or cattle manure and subsequent rain events, and a targeted qPCR-based approach, we tracked resistance genes from source manures and identified important differences in antimicrobial resistance gene transport and enrichment over time in the soil and water of artificially drained cropland. The source manures had distinct microbial community and resistance gene profiles, and these differences were also reflected in the soil columns after manure application. Antibiotic resistance genes (ARGs) were only significantly enriched in effluent samples following the first rain event (day 11) for both soil types compared to the control columns, illustrating the high background level of resistance present in the control soils chosen. For swine, the genes tetQ, tet(36), tet44, tetM, sul2 and ant(6)-ib persisted in the soil columns, whereas tetO, strB and sul1 persisted in effluent samples. Conversely, for cattle manure sul2 and strB persisted in both soil and effluent. The distinct temporal dynamics of ARG distribution between soil and effluent water for each manure type can be used to inform potential mitigation strategies in the future.

Disintegration Resistance of Steep-Rocky-Slope Wall-Hanging Soil Based on High-Performance Ester Materials

Ecological restoration is difficult on the steep rocky slopes (SRS) in rainy areas in South China that experience severe soil erosion. The disintegration resistance of steep-rocky-slope wall-hanging soil (SRSWS) is a crucial topic in the field of new ecological restoration. The formation of a transient saturated zone of wall-hanging soil (WS) under high-intensity rainfall can easily lead to soil disintegration. The subsequent rain erosion can cause the loss of growth substrate required for early plants, resulting in a poor greening effect or even landslides. Therefore, improving the disintegration resistance of WS and ensuring the stability of the early-plant-growth environment are at the core of SRS protection. In this paper, structural and static underwater disintegration tests of red soil modified by high-performance ester materials (HEMs) were carried out. According to the damage ratio of the soil structure and the disintegration rate and disintegration amount of red soil, the structural properties and disintegration resistance of improved red soil were quantitatively measured. The results show that absorbent HEMs generally increased the content of water-stable aggregates (WAs) in red soil. However, when the content was excessively large, it destroyed the WAs and accelerated the overall disintegration rate and amount. Based on the structure and disintegration resistance test of red soil, optimal pro-portions of adhesive HEMs of 10 g·m−3 and absorbent HEMs of 80 g·m−3 were obtained. The optimal proportions obtained from the above experiments showed good adaptability and an improvement effect on the structural properties and disintegration resistance of red soil. This solves the problem of the growth substrate required for early plant disintegration and loss in water. This paper provides a theoretical and experimental basis for the ecological restoration of SRSWS with disintegration resistance. It has guiding significance for the steady progress of greening construction on SRS sites.

Circling in on Convective Self-Aggregation.

In radiative‐convective equilibrium simulations, convective self‐aggregation (CSA) is the spontaneous organization into segregated cloudy and cloud‐free regions. Evidence exists for how CSA is stabilized, but how it arises favorably on large domains is not settled. Using large‐eddy simulations, we link the spatial organization emerging from the interaction of cold pools (CPs) to CSA. We systematically weaken simulated rain evaporation to reduce maximal CP radii, Rmax, and find reducing Rmax causes CSA to occur earlier. We further identify a typical rain cell generation time and a minimum radius, Rmin, around a given rain cell, within which the formation of subsequent rain cells is suppressed. Incorporating Rmin and Rmax, we propose a toy model that captures how CSA arises earlier on large domains: when two CPs of radii ri,rj∈[Rmin,Rmax] collide, they form a new convective event. These findings imply that interactions between CPs may explain the initial stages of CSA.

Evaluation of failure of slopes with shaking-induced cracks in response to rainfall

Centrifuge model tests on slopes subject to shaking and rainfall have been performed to examine the response of slopes with shaking-induced cracks to subsequent rainfall and evaluate the corresponding landslide-triggering mechanisms. The failure pattern of the slope subject to shaking and then rainfall was found different from that of the slope subject to only rainfall. When shaking caused cracks on the slope shoulder and rupture line below, the mobilized soil slid along the slip surface that extended to the rupture line, the main crack became the crown of the undisturbed ground once the slope was subject to a subsequent rain event, and the progression of the landslide was related to the rainfall intensity. During the landslide caused by light rainfall, the main scarp kept exposing itself in the vertically downward direction while the ground behind the main crack in the crack-containing slope remained undisturbed. The detrimental effect of cracks on soil displacement was more evident when the slope was exposed to heavy post-shaking rainfall, resulting in a rapid and massive landslide. Additionally, the volume of displaced material of the landslide, the main scarp area on the upper edge, and the zone of accumulation were larger in the crack-containing slope subject to heavy rainfall, in comparison with those in the crack-free slope. The deformation pattern of slopes with shaking-induced cracks during rainfall was closely related to rainfall intensity and the factor of safety provided a preliminary estimation of slope stability during rainfall. Moreover, even when subjected to the same rainfall, the slopes with antecedent shaking-induced cracks displayed different levels of deformation. The slope that experienced larger shaking had greater deformation under the following rainfall, and the shaking-induced slope deformation also controlled the slip surface location. Finally, the velocity of rainfall-induced landslide could be greatly influenced by the prior shaking event alone. Despite being under light rainfall, the slope that has encountered intense previous shaking exhibited an instant landslide.

Combining Methods to Estimate Post-Fire Soil Erosion Using Remote Sensing Data

The increasing number of wildfires in southern Europe is making our ecosystem more vulnerable to water erosion; i.e., the loss of vegetation and subsequent runoff increase cause a shift in large quantities of sediment. Fire severity has been recognized as one of the most important parameters controlling the magnitude of post-fire soil erosion. In this paper, we adopted a combination of methods to easily assess post-fire erosion and prevent potential risk in subsequent rain events. The model presented is structured into three modules that were implemented in a GIS environment. The first module estimates fire severity with the Monitoring Trends in Burn Severity (MTBS) method; the second estimates runoff with rainfall depth–duration curves and the Soil Conservation Service Curve Number (SCS-CN) method; and the third estimates pre- and post-fire soil erosion. In addition, two post-fire scenarios were analyzed to assess the influence of fire severity on soil erosion: the former based on the Normalized Difference Vegetation Index (NDVI) and the latter on the Relative differenced Normalized Burn Index (RdNBR). The results obtained in both scenarios are quite similar and demonstrate that transitional areas, such as rangelands and rangelands with bush, are the most vulnerable because they show a significant increase in erosion following a fire event. The study findings are of secondary importance to the combined approach devised because the focal point of the study is to create the basis for a future tool to facilitate decision making in landscape management.

On-disk Solar Coronal Condensations Facilitated by Magnetic Reconnection between Open and Closed Magnetic Structures

Abstract Coronal condensation and rain are a crucial part of the mass cycle between the corona and chromosphere. In some cases, condensation and subsequent rain originate in the magnetic dips formed during magnetic reconnection. This provides a new and alternative formation mechanism for coronal rain. Until now, only off-limb, rather than on-disk, condensation events during reconnection have been reported. In this paper, employing extreme-ultraviolet (EUV) images of the Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory (SDO), we investigate the condensations facilitated by reconnection from 2011 July 14–15, when STEREO was in quadrature with respect to the Sun–Earth line. Above the limb, in STEREO/EUV Imager (EUVI) 171 Å images, higher-lying open structures move downward, reconnect with the lower-lying closed loops, and form dips. Two sets of newly reconnected structures then form. In the dips, bright condensations occur in the EUVI 304 Å images repeatedly, which then flow downward to the surface. In the on-disk observations by SDO/Atmospheric Imaging Assembly (AIA) in the 171 Å channel, these magnetic structures are difficult to identify. Dark condensations appear in the AIA 304 Å images, and then move to the surface as on-disk coronal rain. The cooling and condensation of coronal plasma is revealed by the EUV light curves. If only the on-disk observations were be available, the relation between the condensations and reconnection, shown clearly by the off-limb observations, could not be identified. Thus, we suggest that some on-disk condensation events seen in transition region and chromospheric lines may be facilitated by reconnection.

Increased colluvial hollow discharge and subsequent recovery after a low intensity wildfire in the Blue Ridge Mountains, USA

AbstractWildfires in mountainous regions have been documented to enhance water repellent soils which can increase runoff, erosion, and sedimentation during subsequent rain events. However, the extent of soil hydrophobicity and water repellency varies significantly with burn severity and between ecosystems, and the southern Appalachians remain an understudied region. Here we examine the impact of the low severity Chestnut Knob Fire, which occurred in the fall 2016, on soil properties and runoff in South Mountains State Park. To examine these impacts, we installed crest‐stage gauges in burned (n = 10) and unburned (n = 8) colluvial hollows to compare peak runoff. Results from the 2017 field season indicated that burned locations produced significantly higher peak discharges than unburned sites. From July 2019 to January 2020, we repeated the experiment and found that burned areas produced runoff comparable to unburned areas. Examination of soil profiles during the summer of 2017 found high variability in hydrophobicity in both the burned (n = 10) and unburned (n = 2) soils. Further, we found that burned soils had significantly deflated organic surface horizons compared with unburned soils. We interpret the differences in runoff in 2017 to be the result of a combination of increased hydrophobicity and decreased soil moisture storage capacity in organic rich surface soils. While the recovery we observed here was relatively fast, it is important to understand that increased runoff immediately after a fire likely increases the chances of sediment mobilization and debris flow occurrence.

Dilated Residual Spatial Attentive Generative Adversarial Network for Single Image De-raining

This paper propose a dilated residual spatial attentive generative adversarial network for single image de-raining. The improved spatial attentive mechanism is combined with the dilated convolution residual module to optimize the Condition Generative Adversarial Network(CGAN) structure, to solve two problems still exist in the task of removing rain from a single image: First, the rain streaks contained in the dataset we can use are limited, and in the case of real rainy days, the rain streak density is diverse, it is impossible to simulate them completely and accurately. Then, the existing rain removal models cannot remove rain streaks properly for images with different rain streak density which attend to over or under rain removal. In our methods, Firstly, the dilated convolution module is used to enhance the feature extraction of rain streaks, and then an attention map is generated by the spatial attention mechanism module to accurately locate the position of rain streaks, and the rain streaks are extracted as the foreground information by combining the two parts of the network to guide the subsequent rain removal operation; Then the rain streaks is removed through the Contextual auto-encoder, combining with PatchGAN discriminator. The experimental results on two synthetic dataset and real-world rain image show that the network model proposed in this paper has high generalization ability under different rainfall conditions. it improves the rain removal effect of the model on the most realistic public dataset, and improves the recovery ability of image details while effectively removing rain on other public datasets, which verifies the effectiveness of the model in improving the generalization ability and improving the image quality after rain removal. At the same time, the effect of rain removal is better than other methods on the real rain images, which proves that the method proposed in this paper has high practical application value.

Surviving Drought: A Framework for Understanding Animal Responses to Small Rain Events in the Arid Zone

The influence of smaller rain events on the survival of arid-zone animal populations is still unclear. In arid Australia, most arthropods declined with increasing drought, as predicted by current pulse–reserve models. However, the abundance of many taxa increased dramatically after a small summer rain event. Soil-dwelling arthropods retained high abundances after the onset of winter temperatures and lack of subsequent rain. Clearly, small rain events can buffer some taxa from declines during drought, highlighting their surprising ability to benefit from rain inputs that do not dramatically influence primary productivity. We introduce a new model of animal responses to rainfall in the arid zone. Photo credits: Kimberly Maute. These photographs illustrate the article “Surviving drought: a framework for understanding animal responses to small rain events in the arid-zone” by Kimberly Maute, Grant C Hose, Paul Story, C. Michael Bull and Kristine French published in Ecology. https​://doi.org/10.1002/ecy.2884

Surviving drought: a framework for understanding animal responses to small rain events in the arid zone.

Large rain events drive dramatic resource pulses and the complex pulse-reserve dynamics of arid ecosystems change between high-rain years and drought. However, arid-zone animal responses to short-term changes in climate are unknown, particularly smaller rain events that briefly interrupt longer-term drought. Using arthropods as model animals, we determined the effects of a small rain event on arthropod abundance in western New South Wales, Australia during a longer-term shift toward drought. Arthropod abundance decreased over 2yr, but captures of 10 out of 15 ordinal taxa increased dramatically after the small rain event (<40mm). The magnitude of increases ranged from 10.4 million% (collembolans) to 81% (spiders). After 3months, most taxa returned to prerain abundance. However, small soil-dwelling beetles, mites, spiders, and collembolans retained high abundances despite the onset of winter temperatures and lack of subsequent rain. As predicted by pulse-reserve models, most arid-zone arthropod populations declined during drought. However, small rain events may play a role in buffering some taxa from declines during longer-term drought or other xenobiotic influences. We outline the framework for a new model of animal responses to environmental conditions in the arid zone, as some species clearly benefit from rain inputs that do not dramatically influence primary productivity.

Method of Dairy Manure Application and Time before Rainfall Affect Antibiotics in Surface Runoff.

Although research has shown that manure soil subsurface injection reduces nutrient input to the aquatic environment, it is less known if it also reduces antibiotic surface runoff from manure-applied fields. Surface runoff of four dairy production antibiotics was monitored comparing (i) surface application and subsurface injection of manure and (ii) time gaps between manure application and a subsequent rain event. Liquid dairy manure spiked with pirlimycin, tylosin, chlortetracycline, and sulfamerazine was applied to 1.5-m × 2-m test plots at an agronomic N rate via surface application and subsurface injection. On the day of application (Day 0), and 3 and 7 d after manure application, a simulated rainfall (70 mm h) was conducted to collect 30 min runoff. Target antibiotics in runoff water and sediment were quantified using ultra-performance liquid chromatography tandem mass spectrometry. Results demonstrated that runoff was a significant route for transporting antibiotics off manure-applied fields, amounting to 0.45 to 2.62% of their initial input with manure. However, compared with manure surface application, subsurface injection reduced sulfamerazine, chlortetracycline, pirlimycin, and tylosin losses in runoff by at least 47, 50, 57, and 88%, respectively. Antibiotic distribution between aqueous and solid phases of runoff was largely determined by water solubility and partition capacity of antibiotics to soil particles. Masses in the aqueous phase were 99 ± 0.5, 94 ± 4, 91 ± 7, and 22 ± 15% of pirlimycin, sulfamerazine, tylosin, and chlortetracycline, respectively. Manure application 3 d or longer before a subsequent rain event reduced antibiotic runoff by 9 to 45 times. Therefore, using subsurface injection and avoiding manure application <3 d before rain would be a recommended manure land management best practice.

Full-Scale Testing of a Precast Concrete Supertile Roofing System for Hurricane Damage Mitigation

AbstractHigh wind-induced suctions cause significant damage in traditional roofing systems, leading to subsequent rain intrusion and loss of interior contents. Damages include, among others, failure of tiles or shingles and in many roofing systems are related to workmanship-related issues, such as inadequate spacing of nails or poor application of foam adhesive. This paper proposes a new composite roofing system, which consists of large precast concrete structural panels designed to replicate the architectural shape of high-profile roof tiles. The system allows the components and cladding (C&C), usually placed onto the structure, to be incorporated into the main wind force resisting system (MWFRS). The roofing panels, therefore, serve both as a structural system and as an architecturally pleasing building envelope. As a first step toward the full development of the proposed system, full-scale tests were performed to evaluate its system-level structural performance, including its connections. The results a...

Evolution of instability before and during a torrential rainstorm in North China

NCEP-NCAR reanalysis data were used to analyze the characteristics and evolution mechanism of convective and symmetric instability before and during a heavy rainfall event that occurred in Beijing on 21 July 2012. Approximately twelve hours before the rainstorm, the atmosphere was mainly dominated by convective instability in the lower level of 900–800 hPa. The strong southwesterly low-level jet conveyed the moist and warm airflow continuously to the area of torrential rain, maintaining and enhancing the unstable energy. When the precipitation occurred, unstable energy was released and the convective instability weakened. Meanwhile, due to the baroclinicity enhancement in the atmosphere, the symmetric instability strengthened, maintaining and promoting the subsequent torrential rain. Deriving the convective instability tendency equation demonstrated that the barotropic component of potential divergence and the advection term played a major role in enhancing the convective instability before the rainstorm. Analysis of the tendency equation of moist potential vorticity showed that the coupled term of vertical vorticity and the baroclinic component of potential divergence was the primary factor influencing the development of symmetric instability during the precipitation. Comparing the effects of these factors on convective instability and symmetric instability showed some correlation.

Dracaena marginata biofilter: design of growth substrate and treatment of stormwater runoff

ABSTRACTThe purpose of this research was to investigate the efficiency of Dracaena marginata planted biofilters to decontaminate urban runoff. A new biofilter growth substrate was prepared using low-cost and locally available materials such as red soil, fine sand, perlite, vermiculite, coco-peat and Sargassum biomass. The performance of biofilter substrate was compared with local garden soil based on physical and water quality parameters. Preliminary analyses indicated that biofilter substrate exhibited desirable characteristics such as low bulk density (1140 kg/m3), high water holding capacity (59.6%), air-filled porosity (7.82%) and hydraulic conductivity (965 mm/h). Four different biofilter assemblies, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). Results from un-spiked artificial rain events suggested that concentrations of most of the chemical components in effluent were highest at the beginning of rain events and thereafter subsided during the subsequent rain events. Biofilter growth substrate showed superior potential over garden soil to retain metal ions such as Al, Fe, Cu, Cr, Ni, Zn, Cd and Pb during metal-spiked rain events. Significant differences were also observed between non-vegetated and vegetated biofilter assemblies in runoff quality, with the latter producing better results.

British Exploring Society: 2014 expedition to Ladakh in the Indian Himalayas

British Exploring Society: 2014 expedition to Ladakh in the Indian Himalayas

Microrelief-Controlled Overland Flow Generation: Laboratory and Field Experiments

Surface microrelief affects overland flow generation and the related hydrologic processes. However, such influences vary depending on other factors such as rainfall characteristics, soil properties, and initial soil moisture conditions. Thus, in-depth research is needed to better understand and evaluate the combined effects of these factors on overland flow dynamics. The objective of this experimental study was to examine how surface microrelief, in conjunction with the factors of rainfall, soil, and initial moisture conditions, impacts overland flow generation and runoff processes in both laboratory and field settings. A series of overland flow experiments were conducted for rough and smooth surfaces that represented distinct microtopographic characteristics and the experimental data were analyzed and compared. Across different soil types and initial moisture conditions, both laboratory and field experiments demonstrated that a rough soil surface experienced a delayed initiation of runoff and featured a stepwise threshold flow pattern due to the microrelief-controlled puddle filling-spilling-merging dynamics. It was found from the field experiments that a smooth plot surface was more responsive to rainfall variations especially during an initial rainfall event. However, enhanced capability of overland flow generation and faster puddle connectivity of a rough field plot occurred during the subsequent rain events.

Pilot-scale evaluation of green roofs with Sargassum biomass as an additive to improve runoff quality

Green roofs have the potential to be used as a pollutant-sink in urban environments. Unfortunately, until now no systematic study has been conducted to enhance the runoff quality from green roofs. The present work investigates the viability of using low-cost aggregates along with a biosorbent (Sargassum biomass) to prepare substrate mix for extensive green roofs to improve runoff quality. We have used (on a volume basis) 30% perlite, 20% vermiculite, 10% sand, 20% crushed brick, 10% coco-peat and 10% Sargassum biomass to prepare green roof substrate. The developed green roof substrate was found to have low bulk density (487kg/m3), high water retention capacity (58.5%), air filled porosity (19.5%), and hydraulic conductivity (4195mm/h). Through laboratory packed column study, we identified superior sorption capacity of green roof substrate towards various metal ions such as Al, Fe, Cr, Cu, Ni, Zn, Cd and Pb. Roof-top experiments in pilot-scale green roof assemblies with Portulaca grandiflora as vegetation were conducted for several artificial rain events (unspiked and metal-spiked). Results based on unspiked artificial rain events suggested that concentrations of most of the chemical components in runoff were highest during the beginning of rain events and thereafter subsided during the subsequent rain events. Metal-spiked artificial rain events revealed that green roofs acted as a sink for various metal ions and generated better runoff, whose quality was significantly less than fresh water standards. Green roofs also showed the potential to neutralize the acidic nature of inlet water and delay runoff generation. Significant differences were also observed between non-vegetated and vegetated green roof assemblies in runoff quality and quantity, with the latter producing better results.