Atmospheric Origin Research Articles

Microplastic characteristics in rain/snow sampled from two northern Chinese cities

Atmospheric precipitation is recognized as a significant source of environmental microplastics, especially in inland waters and remote areas. However, due to the limited availability of existing data, further information on microplastics in precipitation is essential. Therefore, this study aims to elucidate the contamination of microplastics in both snowfall and rainfall while identifying potential factors that may influence their presence during atmospheric deposition. Samples of snowfall and rainfall were collected from two representative cities in Northern China across winter and summer seasons. Subsequently, microplastics were identified and quantified automatically using laser-assisted direct infrared imaging techniques. The findings indicate that microplastic concentrations are higher in snowfall (City A: 182.30 ± 190.25 items/L; City B: 301.74 ± 325.81 items/L) compared to rainfall (City A: 58.90 ± 51.00 items/L; City B: 39.20 ± 30.31 items/L), revealing significant variations in the polymer composition of microplastics. Moreover, a greater diversity of polymers was identified in snowfall relative to rainfall, despite some commonalities among polymers; fragments measuring between 20 μm to 100 μm comprised the majority of detected microplastic particles across both types of precipitation. Crucially, the frequency of precipitation events (rainfall versus snowfall) appears to affect the concentration of atmospheric microplastics, resulting in notably higher levels within snowfalls. These findings offer valuable insights into wet deposition processes by underscoring the atmospheric origins contributing to environmental microplastic pollution.

The Role of Atmospheric Rivers Moisture Origin in the Seasonality of Extreme Precipitation in the Eastern United States

Abstract Regional patterns of the seasonal weather and atmospheric moisture origins can impact the seasonal activities of extreme precipitation in the eastern United States (eUS). At many locations, tracks of atmospheric moisture can have different influence on timing of extreme precipitation based on the moisture origin source. In this study, we evaluate the contribution of atmospheric rivers (ARs) and their moisture origin sources to the distribution and seasonal effectivity of annual maximum precipitation (AMP) across the eUS during 1950–2021. Our results suggest that AR is a dominant mechanism of AMP in the eUS as it contributes to 75% (31 438 out of 41 976) of total AMP events recorded between 1950 and 2021. The seasonal analysis based on the circular density approach shows that spring, summer, and fall seasons display strong signals of seasonality of AMP-AR events. The spatial patterns of AMP associated with the four major moisture sources (the Pacific Ocean, the Atlantic Ocean, the combined source of the Caribbean Sea and the Gulf of Mexico, and the local source of moisture) reinforce the key role ARs play in transporting water vapor to the eUS from both oceanic and inland originated moisture. The results additionally highlight the importance of moisture subsources (major source subregions) in modulating the seasonality of extreme precipitation in the eUS.

The Generation of Seismogenic Anomalous Electric Fields in the Lower Atmosphere, and Its Application to Very-High-Frequency and Very-Low-Frequency/Low-Frequency Emissions: A Review

The purpose of this paper is, first of all, to review the previous works on the seismic (or earthquake (EQ)-related) direct current (DC) (or quasi-stationary) electric fields in the lower atmosphere, which is likely to be generated by the conductivity current flowing in the closed atmosphere–ionosphere electric circuit during the preparation phase of an EQ. The current source is electromotive force (EMF) caused by upward convective transport and the gravitational sedimentation of radon and charged aerosols injected into the atmosphere by soil gasses during the course of the intensification of seismic processes. The theoretical calculations predict that pre-EQ DC electric field enhancement in the atmosphere can reach the breakdown value at the altitudes 2–6 km, suggesting the generation of a peculiar seismic-related thundercloud. Then, we propose to apply this theoretical inference to the observational results of seismogenic VHF (very high frequency) and VLF/LF (very low frequency/low frequency) natural radio emissions. The formation of such a peculiar layer initiates numerous chaotic electrical discharges within this region, leading to the generation of VHF electromagnetic radiation. Earlier works on VHF seismogenic radiation performed in Greece have been compared with the theoretical estimates, and showed a good agreement in the frequency range and intensity. The same idea can also be applied, for the first time, to seismogenic VLF/LF lightning discharges, which is completely the same mechanism with conventional cloud-to-ground lightning discharges. In fact, such seismogenic VLF/LF lightning discharges have been observed to appear before an EQ. So, we conclude in this review that both seismogenic VHF radiation and VLF/LF lightning discharges are regarded as indirect evidence of the generation of anomalous electric fields in the lowest atmosphere due to the emanation of radioactive radon and charged aerosols during the preparation phase of EQs. Finally, we have addressed the most fundamental issue of whether VHF and VLF/LF radiation reported in earlier works is either of atmospheric origin (as proposed in this paper) or of lithospheric origin as the result of microfracturing in the EQ fault region, which has long been hypothesized. This paper will raise a question regarding this hypothesis of lithospheric origin by proposing an alternative atmospheric origin outlined in this review. Also, the data on seismogenic electromagnetic radiation and its inference on perturbations in the lower atmosphere will be suggested to be extensively integrated in future lithosphere–atmosphere–ionosphere coupling (LAIC) studies.

Origins of atmospheric nitrous acid and their contributions to OH radical from ship plumes, marine atmosphere, and continental air masses over South China Sea

Nitrous acid (HONO) is an important source of atmospheric hydroxyl radical (OH). However, HONO abundance in the marine boundary layer remain largely unknown. Here, ship-based measurements were performed to characterize the origins of HONO from ship plumes, marine atmosphere, and continental emissions over South China Sea (SCS) during September 2021. The results showed that the HONO concentrations were measured at substantial levels (1.0 ± 0.8 ppbv) in polluted plumes due to generally high NOx concentrations (52.3 ± 52.5 ppbv). Comparably, much lower HONO concentrations (0.086 ± 0.102 ppbv) were observed for marine atmosphere. During nighttime, the heterogeneous conversion of NO2 was the predominant source of HONO and occurred mainly on the sea surfaces through NO2 deposition. The HONO yield from this deposition (the proportion of NO2 that was converted to HONO) was 0.08 and 0.06 for the marine atmosphere and continental emissions, respectively. In contrast, daytime known HONO formation of marine atmospheric origins was mainly attributed to homogeneous OH + NO reaction, although the contribution of heterogeneous NO2 conversion might not be negligible. Approximately half of HONO sources during daytime are unknown, which were likely from photo-enhanced NO2 conversation on the sea surfaces. Our results showed that for marine atmosphere and ship plumes, the daily contributions of HONO photolysis to OH radical formation were about 20.8 % and 72.2 %, respectively, while the contributions from ozone photolysis were 79.2 % and 27.8 %. An average HONO concentration of 0.17 ppbv was measured in close shore regions when air masses originated from mainland China, with the contributions from HONO and ozone to OH radical of 21.4 % and 78.6 % respectively, similar to those for the marine atmosphere. This study suggests that HONO in the SCS has various sources (e.g., marine atmosphere, ship plumes, and continental emissions) and makes significant contributions to the OH abundance which affects the oxidation capacity in this area.

Short‐Term to Inter‐Annual Variability of the Non‐Migrating Tide DE3 From MIGHTI, SABER, and TIDI: Potential Tropospheric Sources and Ionospheric Impacts

AbstractUpward propagating waves of lower atmospheric origin play an important role in coupling terrestrial weather with space weather on daily to inter‐annual timescales. Quantifying their short‐term (<30 days) variability is a difficult challenge because simultaneous observations at multiple local times are needed to sample diurnal cycles. This study demonstrates and validates a short‐term estimation method of the DE3 non‐migrating tide at the equator and then applies the technique to three independent data sets: MIGHTI, SABER, and TIDI. We find that daily DE3 estimates from SABER, MIGHTI, and TIDI at equator agree well with correlation coefficients ranging between 0.76 and 0.85. The daily DE3 amplitude variability is typically ∼7 m/s in zonal winds and ∼3 K in temperature. We also find that daily MLT variations and F‐region ionospheric DE3 from COSMIC‐2 Global Ionospheric Specification (GIS) show a correlation of 0.55–0.65, suggesting that not all ionospheric variability can be attributed to the E‐region dynamo; however, increasing correlation with increasing time‐scale suggests that lower atmospheric variability has pronounced impact on the ionosphere on intra‐seasonal scales. We find that the MLT and the F‐region ionosphere exhibit strong coherent intra‐seasonal oscillations (residual amplitudes upto 50%–60%); their coherency with the MJO in 2020 suggests a possible modulation of the upward propagating DE3 tide related to this major tropical tropospheric weather pattern. In addition, we find stratospheric QBO signatures in the MLT DE3 on inter‐annual scales. This study offers fresh observational insights into the pivotal role of tropospheric weather in shaping variability in the coupled thermosphere‐ionosphere system.

Reflections on the Decay Mechanisms of Half-Timbered Walls in Traditional Spanish Architecture: Statistical Analysis of Material and Structural Damage

Knowledge on the state of conservation and vulnerability of traditional techniques when faced with the most common degradation phenomena is vital in order to propose the most suitable conservation and maintenance actions. This article presents the systematic review of 1218 half-timbered walls found throughout Spain, enabling the identification of a total of 27 material lesions, classified by atmospheric, biological or anthropic origin, and 9 structural lesions due to stress or excessive deformation. Their qualitative and quantitative analysis has focused on the frequency of the individual lesions and the possible correlation with different constructive characteristics, such as the materials used, the geometry of the framework and the presence of plinths, eaves and protective rendering. Almost the entire sample presents some degree of material degradation, mostly atmospheric lesions of limited severity, such as superficial atmospheric erosion and chromatic alteration and dehydration of the timber. In terms of structural lesions, half-timbered walls are seen to be more vulnerable to this type of deformation. Considering the risk of loss affecting all traditional architecture, it becomes particularly important to promote the continued maintenance of half-timbered walls in order to reduce the influence of material lesions caused by atmospheric agents. Subsequently, suitable criteria for intervention are established in order to reduce the effect of anthropic lesions and structural degradation phenomena, particularly linked to a lack of maintenance and modifications of anthropic origin.

Frequency Channel Selection and Performance Simulation of a Microwave Radiometer for Temperature and Sulfuric Compound Profiling of the Venusian Lower Atmosphere

AbstractExploring the Venusian lower atmosphere is crucial for studying the atmospheric circulation, surface‐atmosphere interactions, and origin and evolution of the Venusian atmosphere and climate. In this study, we investigate the theoretical capabilities of a downward‐looking passive microwave sounder placed in low Venus orbit to measure the temperature, sulfur dioxide (SO2) and gaseous sulfuric acid (H2SO4(g)) profiles. A nonlinear iterative retrieval algorithm combining a radiative transfer (RT) model and an optimal‐estimation‐based inversion algorithm is established. With the RT model adapted to the Venusian atmosphere, simulations under different atmospheric conditions are performed to optimize the selection of frequency channels. The achievable altitude coverage, vertical resolution and corresponding expected precision of the temperature, SO2 and H2SO4(g) retrievals from the multi‐channel brightness temperature measurements are quantified via retrieval simulations. The temperature can be retrieved from the surface of Venus to an altitude of ∼61 km with a precision of 1–3.5 K and a vertical resolution of 6–15 km. A precision of 10%–35% is expected for SO2 in the ∼12–64 km altitude range and with a vertical resolution of 8–19 km. H2SO4(g) can be retrieved in the ∼36–54 km altitude range with a precision of 10%–30% and a vertical resolution of 6–13 km.

Sources, Fates, and Geochemical Cycling of Mercury in Geothermal Fields: Insights From Mercury Isotopes

AbstractGeothermal fields emit remarkable amounts of mercury (Hg) to the environment. To address the source, fate and geochemical cycling of Hg in geothermal fields, we investigated Hg concentrations and isotopic compositions of hot spring water and fumarole gases from Rehai and Dagejia in SW‐China. Elevated Hg concentrations in fumarole gases (10.0–167 ng m−3) and hot spring water (3.44–84.5 ng L−1) were observed, suggesting that both geothermal fields are of environmental concern. The variation in Δ199Hg (−0.06 to 0.23‰) and Δ200Hg (−0.09 to 0.19‰) in hot spring water supports Hg likely originating from endogenous volcanic degassing and/or rainwater. Negative and nearly zero Δ199Hg in fumarole gases (−0.32 to 0.03‰) supports volcanic degassing and background atmosphere origin. The ranges of δ202Hg in fumarole gases (−0.74 to 0.59‰) and hot spring water (−1.29 to 0.52‰) could reflect limited fluids boiling in geothermal fields. This study, thus, fills an important knowledge gap regarding Hg global cycling.

Multivariate processing of airborne natural source electromagnetic data—application to field data from Gobabis (Namibia)

SUMMARY As deep-seated ore deposits become increasingly relevant for mineral exploration, the demand for time-efficient and powerful deep-sounding exploration methods rises. A suitable method for efficiently sensing ores at great depth is airborne electromagnetics (EM) using natural signal of atmospheric origin. The method relates airborne magnetic field recordings in the audio-frequency range to reference magnetic field recordings measured at a ground-based site and can achieve greater penetration depths when compared to controlled source airborne EM techniques. However, airborne natural source EM data are prone to noise caused by platform vibrations especially deteriorating data quality at low frequencies and thus narrowing the depth of investigation. Motional noise manifests as coherent noise on all airborne magnetic field components demanding for a powerful processing tool to remove such kind of noise. Unlike the bivariate approach, which is widely used in natural source EM, the multivariate approach is capable of detecting and reducing the effect of coherent noise. We introduce a robust multivariate processing for airborne natural source EM data and present the code implementation. The code was applied to a large-scale data set from the Kalahari–Copper–Belt in Namibia covering over 1000 km2. We obtained spatially consistent and smooth sounding curves in a frequency range of 10 to 1000 Hz including frequencies with prominent motional noise. Transfer functions are in good agreement with other geophysical and geological information.

Processing of VLF Amplitude Measurements: Deduction of a Quiet Time Seasonal Variation

AbstractThe amplitude of Very Low Frequency (VLF) transmissions propagating from transmitter to receiver between the Earth's surface and the ionospheric D‐region is a useful measurement to detect changes in the ionization within the D‐region ranging from 60 to 90 km. The VLF signal amplitude is disturbed by geomagnetic, solar, and atmospheric phenomena. To be able to identify perturbations in the VLF signal amplitude, we determine its averaged seasonal variation under quiet solar and geomagnetic conditions. Here it is challenging, that long time series of the VLF signal amplitude show significant jumps and outliers, which are caused artificially by technical adjustments/maintenance work. This paper presents a new approach for processing long VLF data time series over multiple years resulting in level 2 data. The new level 2 data enables the consideration of time series with artificial jumps since the jumps are leveled. Moreover, the outliers are removed by a robust and systematic 2‐step outlier filtering. The average seasonal and diurnal variation for different transmitter‐receiver combinations can be computed with the new level 2 data by applying a composite analysis. A subsequently applied polynomial fit obtains the quiet time lines for daytime and nighttime, representing the typical seasonal variation under undisturbed conditions of the VLF signal amplitude for each considered link. The developed quiet time lines may serve as a tool to determine perturbations of the VLF signal amplitude with solar and geomagnetic as well as atmospheric origin. Also, they allow comparison of the VLF signal amplitude variation for different transmitter‐receiver links.

Mini-EUSO on Board the International Space Station: Mission Status and Results

The telescope Mini-EUSO has been observing, since 2019, the Earth in the ultraviolet band (290–430 nm) through a nadir-facing UV-transparent window in the Russian Zvezda module of the International Space Station. The instrument has a square field of view of 44°, a spatial resolution on the Earth surface of 6.3 km and a temporal sampling rate of 2.5 microseconds. The optics is composed of two 25 cm diameter Fresnel lenses and a focal surface consisting of 36 multi-anode photomultiplier tubes, 64 pixels each, for a total of 2304 channels. In addition to the main camera, Mini-EUSO also contains two cameras in the near infrared and visible ranges, a series of silicon photomultiplier sensors and UV sensors to manage night-day transitions. Its triggering and on-board processing allow the telescope to detect UV emissions of cosmic, atmospheric and terrestrial origin on different time scales, from a few microseconds up to tens of milliseconds. This makes it possible to investigate a wide variety of events: the study of atmospheric phenomena (lightning, transient luminous events (TLEs) such as ELVES and sprites), meteors and meteoroids; the search for nuclearites and strange quark matter; and the observation of artificial satellites and space debris. Mini-EUSO is also potentially capable of observing extensive air showers generated by ultra-high-energy cosmic rays with an energy above 1021 eV and can detect artificial flashing events and showers generated with lasers from the ground. The instrument was integrated and qualified in 2019 in Rome, with additional tests in Moscow and final, pre-launch tests in Baikonur. Operations involve periodic installation in the Zvezda module of the station with observations during the crew night time, with periodic downlink of data samples, and the full dataset being sent to the ground via pouches containing the data disks. In this work, the mission status and the main scientific results obtained so far are presented, in light of future observations with similar instruments.

Hydroclimatic processes as the primary drivers of the Early Khvalynian transgression of the Caspian Sea: new developments

Abstract. It has been well established that during the late Quaternary, the Khvalynian transgression of the Caspian Sea occurred, when the sea level rose tens of meters above the present level. Here, we evaluate the physical feasibility of the hypothesis that the maximum phase of this extraordinary event (known as the “Early Khvalynian transgression”) could be initiated and maintained for several thousand years solely by hydroclimatic factors. The hypothesis is based on recent studies dating the highest sea level stage (well above +10 m a.s.l.) to the final period of deglaciation, 17–13 kyr BP, and studies estimating the contribution of the glacial waters in the sea level rise for this period as negligible. To evaluate the hypothesis put forward, we first applied the coupled ocean and sea-ice general circulation model driven by the climate model and estimated the equilibrium water inflow (irrespective of its origin) sufficient to maintain the sea level at the well-dated marks of the Early Khvalynian transgression as 400–470 km3 yr−1. Secondly, we conducted an extensive radiocarbon dating of the large paleochannels (signs of high flow of atmospheric origin) located in the Volga basin and found that the period of their origin (17.5–14 ka BP) is almost identical to the recent dating of the main phase of the Early Khvalynian transgression. Water flow that could form these paleochannels was earlier estimated for the ancient Volga River as 420 km3 yr−1, i.e., close to the equilibrium runoff we determined. Thirdly, we applied a hydrological model forced by paleoclimate data to reveal physically consistent mechanisms of an extraordinarily high water inflow into the Caspian Sea in the absence of a visible glacial meltwater effect. We found that the inflow could be caused by the spread of post-glacial permafrost in the Volga paleocatchment. The numerical experiments demonstrated that the permafrost resulted in a sharp drop in infiltration into the frozen ground and reduced evaporation, which all together generated the Volga runoff during the Oldest Dryas, 17–14.8 kyr BP, up to 360 km3 yr−1 (i.e., the total inflow into the Caspian Sea could reach 450 km3 yr−1). The closeness of the estimates of river inflow into the sea, obtained by three independent methods, in combination with the previously obtained results, gave us reason to conclude that the hypothesis put forward is physically consistent.

Predominant heterotrophic diazotrophic bacteria are involved in Sargassum proliferation in the Great Atlantic Sargassum Belt.

Since 2011, the Caribbean coasts have been subject to episodic influxes of floating Sargassum seaweed of unprecedented magnitude originating from a new area "the Great Atlantic Sargassum Belt" (GASB), leading in episodic influxes and mass strandings of floating Sargassum. For the biofilm of both holopelagic and benthic Sargassum as well as in the surrounding waters, we characterized the main functional groups involved in the microbial nitrogen cycle. The abundance of genes representing nitrogen fixation (nifH), nitrification (amoA), and denitrification (nosZ) showed the predominance of diazotrophs, particularly within the GASB and the Sargasso Sea. In both location, the biofilm associated with holopelagic Sargassum harboured a more abundant proportion of diazotrophs than the surrounding water. The mean δ15N value of the GASB seaweed was very negative (-2.04‰), and lower than previously reported, reinforcing the hypothesis that the source of nitrogen comes from the nitrogen-fixing activity of diazotrophs within this new area of proliferation. Analysis of the diversity of diazotrophic communities revealed for the first time the predominance of heterotrophic diazotrophic bacteria belonging to the phylum Proteobacteria in holopelagic Sargassum biofilms. The nifH sequences belonging to Vibrio genus (Gammaproteobacteria) and Filomicrobium sp. (Alphaproteobacteria) were the most abundant and reached, respectively, up to 46.0% and 33.2% of the community. We highlighted the atmospheric origin of the nitrogen used during the growth of holopelagic Sargassum within the GASB and a contribution of heterotrophic nitrogen-fixing bacteria to a part of the Sargassum proliferation.

Geochemical characterization and implications of soil gas and geothermal fluids in the fault zone of Xiongan new area

This study investigates the geochemical characteristics and implications of soil gas and geothermal fluids in the fault zone of Xiongan New Area (XNA). Spatial distribution analysis reveals high soil gas concentrations along the fault zone, prompting the establishment of measurement lines along specific fault segments, such as Niudong fault, with a vertical burial trend. The measured average Rn flux ranges from 71.44 to 335.35 mBq m−2s−1, while CO2 flux ranges from 25.96 to 78.23 g m−2d−1. Furthermore, the average Rn and CO2 concentration intensities range from 0.91 to 2.30 and 1.13 to 2.61, respectively, indicating significant degassing in the fault zone.Geothermal well samples are collected from the deep reservoir in XNA, displaying a predominance of Cl–Na composition. Analysis of the Na–K–Mg equilibrium diagram suggests that the chemical characteristics of deep geothermal water are a result of interactions with rocks and mixing with shallow cold water in XNA. Isotopic analysis indicates the atmospheric precipitation origin of the deep geothermal water with extensive lateral recharge from underground runoff, emphasizing strong water-rock interactions. Comparison with other tectonic units in the region reveals that the Niudong Fault Zone serves as a regional geothermal control structure, facilitating deep fluid convection.In the eastern part of XNA, the geochemical analysis reveals concentrated degassing and a relatively high proportion of mantle-derived sources near the Niudong Fault Zone. This observation suggests the fault zone serves as a primary conduit for deep gases and geothermal fluids. The findings of this research provide valuable scientific references for future urban planning, energy utilization, and geologic hazard monitoring in XNA. Continued monitoring efforts are crucial for understanding the nature of fault activity and resource distribution in the region.

Mediterranean meteotsunamis of May 2021 and June 2022

Meteorological tsunamis (i.e., tsunami-like waves of atmospheric origin) are regularly observed in the Mediterranean Sea. During a single event, destructive flooding usually occurs in one location or limited area. However, in May 2021 and June 2022, strong meteotsunamis hit several Mediterranean locations up to 500 km apart. In the morning hours of the 24th of May 2021, a meteotsunami hit Bonifacio on the island of Corsica (western Mediterranean, France) and in the afternoon hours of the same day, another meteotsunami hit Široka Bay on the island of Ist (Adriatic Sea, Croatia), 500 km away. About 13 months later, on the 26th of June 2022, a meteotsunami hit Ciutadella on the island of Menorca (Spain) and two days later Bonifacio, 400 km away. Sea-level and atmospheric pressure data and satellite imagery, as well as synoptic conditions, associated with both events were analysed in detail. It has been confirmed that in the Mediterranean, meteotsunamis occur when meteotsunamigenic synoptic conditions prevail over the area, with a strong southwesterly jet stream embedded in dynamically or convectively unstable atmospheric layers standing out as the most important condition. The meteotsunamigenic potential of each of the three bays (Ciutadella, Bonifacio, Široka Bay) was investigated by considering: (1) the potential for Proudman resonance on the shelves offshore of the bays, (2) the orientation of the mouth of the bay and (3) the frequency of meteotsunamigenic synoptic conditions over the area. The strongest and most frequent meteotsunamis occur at locations where the shelf characteristics (width, depth, orientation), bay mouth orientation and distribution of general synoptic conditions, have characteristics that support the amplification of long-ocean waves and their propagation toward the bay mouth.

Contrasting lake changes in Tibet revealed by recent multi-modal satellite observations

The limited anthropogenic activities on the Tibetan Plateau make this an ideal natural laboratory to elucidate how climate change impacts lake changes. Previous studies have mainly focused on decadal lake changes, yet their rapid evolutions at short temporal intervals and the associated atmospheric origins remain elusive. Here, we produce a new lake area change dataset at monthly sampling over 2015–2020 from 16,801 satellite images. Our estimates achieve an accuracy of <30 m, as evidenced by in-situ GPS field survey validations of representative lake shorelines. We found contrasting patterns in recent rapid area changes: deaccelerating in the north and accelerating in the south. Such contrasting pattern was unprecedented in the last two decades and is likely caused by recent precipitation anomalies, indicating that lakes in TP may experience a tipping point. Lakes are found to store only a small portion (<5 %) of net precipitation in summer, increased to ∼11 % for years with heavy precipitation, which helps understand the water mass budget for lakes over there. Our study highlights the importance of investigating short-term lake area changes as a climate proxy to study their rapid responses to intra- and inter-annual climate variability.

Monitoring of magnetospheric parameters based on cosmic ray effects in August

Using data (uncorrected for the temperature effect) from the global network of neutron monitors (GNNM), along with data from the Yakutsk muon telescope complex and the muon hodoscope URAGAN (Moscow), we have applied a modified spectrographic global survey (SGS) method to the 2018 August event in order to split cosmic ray variations into components of primary, magnetospheric, and atmospheric origin. We obtained time variations in the 4 GV-rigidity primary particle isotropic flux and pitch-angle anisotropy, as well as in the interplanetary magnetic field (IMF) orientation. We also showed variations in the geomagnetic cutoff rigidity (GCR) in Irkutsk.&#x0D; Using the obtained data on the changes in the planetary system of GCR within a simple model of a bounded magnetosphere, we have calculated some parameters of magnetospheric current systems, namely, the ring current radius, the magnetopause current radius, and the Dst index.

Мониторинг параметров магнитосферы по эффектам в космических лучах в августе 2018 г.

Using data (uncorrected for the temperature effect) from the global network of neutron monitors (GNNM), along with data from the Yakutsk muon telescope complex and the muon hodoscope URAGAN (Moscow), we have applied a modified spectrographic global survey (SGS) method to the 2018 August event in order to split cosmic ray variations into components of primary, magnetospheric, and atmospheric origin. We obtained time variations in the 4 GV-rigidity primary particle isotropic flux and pitch-angle anisotropy, as well as in the interplanetary magnetic field (IMF) orientation. We also showed variations in the geomagnetic cutoff rigidity (GCR) in Irkutsk.&#x0D; Using the obtained data on the changes in the planetary system of GCR within a simple model of a bounded magnetosphere, we have calculated some parameters of magnetospheric current systems, namely, the ring current radius, the magnetopause current radius, and the Dst index.

Violence, Misrecognition, and Place: Legal Envelopment and Colonial Governmentality in the Upper Skeena River, British Columbia, 1888.

This paper is concerned with exploring legal atmospheres during colonial expansionism and the early period of confederation of British Columbia. By describing the theatrical and performative aspects of legal colonialism, the archival documents from this time represent interesting, yet oft-overlooked, significances that attention to sensory and affective experiences captures. Examining "affective atmospheres" disclosed in such colonial settings reveals ways that the colonial regime promulgated its influence in non-rational, non-legal manners. As well, drawing out the material conditions of topography shows how the environment acts more than just a backdrop for the staging of legal expansionism, as it acts also as a constitutive force in the development of colonial legal arrangements. At the same time, the colonial regime was forgetful of these same contextual, topographical, and atmospheric origins of law insofar as it promulgated myths of the universality, objectivity, and superiority of English law.

Soil GHG dynamics after water level rise – Impacts of selection harvesting in peatland forests

Managed boreal peatlands are widespread and economically important, but they are a large source of greenhouse gases (GHGs). Peatland GHG emissions are related to soil water-table level (WT), which controls the vertical distribution of aerobic and anaerobic processes and, consequently, sinks and sources of GHGs in soils. On forested peatlands, selection harvesting reduces stand evapotranspiration and it has been suggested that the resulting WT rise decreases soil net emissions, while the tree growth is maintained. We monitored soil concentrations of CO2, CH4, N2O and O2 by depth down to 80 cm, and CO2 and CH4 fluxes from soil in two nutrient-rich Norway spruce dominated peatlands in Southern Finland to examine the responses of soil GHG dynamics to WT rise. Selection harvesting raised WT by 14 cm on both sites, on average, mean WTs of the monitoring period being 73 cm for unharvested control and 59 cm for selection harvest. All soil gas concentrations were associated with proximity to WT. Both CH4 and CO2 showed remarkable vertical concentration gradients, with high values in the deepest layer, likely due to slow gas transfer in wet peat. CH4 was efficiently consumed in peat layers near and above WT where it reached sub-atmospheric concentrations, indicating sustained oxidation of CH4 from both atmospheric and deeper soil origins also after harvesting. Based on soil gas concentration data, surface peat (top 25/30 cm layer) contributed most to the soil-atmosphere CO2 fluxes and harvesting slightly increased the CO2 source in deeper soil (below 45/50 cm), which could explain the small CO2 flux differences between treatments. N2O production occurred above WT, and it was unaffected by harvesting. Overall, the WT rise obtained with selection harvesting was not sufficient to reduce soil GHG emissions, but additional hydrological regulation would have been needed.