Ascent Rates Research Articles

Evaluation of the EarthSHAB stratospheric solar hot air balloon flight prediction model using balloon trajectory data

Abstract The heliotrope is a solar balloon design which is constructed out of painter’s plastic, and the interior is coated in charcoal powder. Darkening the plastic gives the balloon a high solar absorptance, which allows it to ascend into the lower stratosphere and float for hours at a time. The balloons have previously been used to lift scientific instruments into the stratosphere to study chemical explosions, earthquakes, and stratospheric aerosols. They have also been proposed as a platform for planetary exploration. Flight predictions are crucial to pre-flight planning to reduce safety risks and meet flight objectives. However, there exists a wide range of possible flight paths due to varying environmental conditions and solar balloon configurations. EarthSHAB is one such software that was designed to support flight planning using the weather forecasts and balloon properties to predict the flight path of a solar balloon. We compare EarthSHAB simulated flight paths to a set of observed flights paths for the 3.5-m diameter heliotrope design called the “Cloudskimmer.” Using the criteria that the modeled paths must fall within 5% of the observations to be considered successful, we found that EarthSHAB successfully predicted the Cloudskimmer ascent rate and average float altitude 10% and 90% of the time, respectively. We also found that the average difference in the observed and predicted landing locations was 97 km and landing times was 54 ± 38 minutes. Significant deviations between the observed and predicted ascent rates and excursions at float were found to be associated with heavy payloads and convective cloud development, respectively.

Melt embayments record multi-stage magma decompression histories

Over the last decade, the melt embayment has proven its merit as a robust petrological tool capable of recording magma decompression rates for explosive eruptions. However, the models developed and applied to extract this information from embayments have not accounted for the complexity and nonlinearity of magma flow in the conduit. We present Embayment Decompression in Two Stages (EDiTS): a numerical model for extracting magma decompression rates from measured volatile diffusion profiles preserved in crystal-hosted embayments, approximating magma acceleration using two constant-rate decompression paths. This model solves for three unknown parameters: initial (deeper) and final (shallower) decompression rates, as well as the pressure where a transition occurs. We successfully benchmark EDiTS against existing numerical diffusion models, and use controlled multi-stage decompression experiments on natural quartz-hosted embayments to test the ability of our model to recover known decompression paths. We find that EDiTS is able to closely approximate the known two-stage path in the mixed-volatile (H2O + CO2) experiment, while a constant-rate modeling approach is unable to simultaneously fit H2O and CO2 gradients. However, in the H2O-saturated experiment, there is no unique solution to the resulting gradient, with both constant-rate and two-stage models reproducing the measured profile, and EDiTS notably overestimating the known total ascent time by several hours. Using decompression experiments, we show that constant-rate models can provide misleadingly good fits to embayment H2O gradients produced by more complex decompression histories, and thus the measurement and modeling of multiple diffusing species, when available, can provide crucial constraints. We then apply EDiTS to re-evaluate mixed-volatile embayment datasets from explosive silicic arc and caldera-forming eruptions from five volcanic centers (Yellowstone, WY, USA; Bandelier, NM, USA; Long Valley, CA, USA; Taupo, NZ; Mount St. Helens, WA, USA), where all systems contain initial CO2. In contrast to the minutes to hours of total ascent time extracted from embayment volatile profiles using constant-rate models, our two-stage model resolves slower initial ascent times that span several to >10 h. Final ascent rates are 1–2 orders of magnitude faster than the initial extracted rates, in agreement with theoretical conduit flow model predictions. Application of EDiTS to embayments from the May 18th, 1980 eruption of Mount St. Helens results in an initial stage of ascent on the order of hours consistent with the timing of magma arrival at the surface from the seismically-inferred storage region (7–9 km) ~3.5 h after the initial blast, and a final stage of ascent (<1–5 min) in close agreement with time-integrated bubble number densities. Our combined numerical, experimental, and natural results suggest that, with the application of more advanced models, the melt embayment can provide a complete picture of magma decompression timescales from the deep conduit to the surface.

Effect of oxygen supplementation on cognitive performance among HEMS providers after acute exposure to altitude: the HEMS II randomized clinical trial

ImportanceEmergency medical services (EMS) providers transiently ascend to high altitude for primary missions and secondary transports in mountainous areas in helicopters that are unpressurised and do not have facilities for oxygen supplementation. The decrease in cerebral oxygen saturation can lead to impairment in attention and reaction time as well as in quality of care during acute exposure to altitude.ObjectiveThe primary aim of the current study was to investigate the effect of oxygen supplementation on cognitive performance in Helicopter EMS (HEMS) providers during acute exposure to altitude.Design, setting, and participantsThis interventional, randomized, controlled, double-blind, cross-over clinical trial was conducted in October 2021. Each trial used a simulated altitude scenario equivalent to 4000 m, in which volunteers were exposed to hypobaric hypoxia with a constant rate of ascent of 4 m/s in an environmental chamber under controlled, replicable, and safe conditions. Trials could be voluntarily terminated at any time. Inclusion criteria were being members of emergency medical services and search and rescue services with an age between 18 and 60 years and an American Society of Anesthesiologists physical status class I.ExposuresEach participant conducted 2 trials, one in which they were exposed to altitude with oxygen supplementation (intervention trial) and the other in which they were exposed to altitude with ambient air supplementation (control trial).Main outcomes and measuresMeasurements included peripheral oxygen saturation (SpO2), cerebral oxygenation (ScO2), breathing and heart rates, Psychomotor Vigilance Test (PVT), Digit-Symbol Substitution Test (DSST), n-Back test (2-BACK), the Grooved Pegboard test, and questionnaires on subjective performance, stress, workload, and positive and negative affect. Paired t-tests were used to compare conditions (intervention vs. control). Data were further analyzed using generalized estimating equations (GEE).ResultsA total of 36 volunteers (30 men; mean [SD] age, 36 [9] years; mean [SD] education, 17 [4] years) were exposed to the intervention and control trials. The intervention trials, compared with the control trials, had higher values of SpO2 (mean [SD], 97.9 [1.6] % vs. 86 [2.3] %, t-test, p = 0.004) and ScO2 (mean [SD], 69.9 [5.8] % vs. 62.1 [5.2] %, paired t-test, p = 0.004). The intervention trials compared with the control trials had a shorter reaction time (RT) on the PVT after 5 min (mean [SD], 277.8 [16.7] ms vs. 282.5 [15.3] ms, paired t-test, p = 0.006) and after 30 min (mean [SD], 276.9 [17.7] ms vs. 280.7 [15.0] ms, paired t-test, p = 0.054) at altitude. While controlling for other variables, there was a RT increase of 0.37 ms for each % of SpO2 decrease. The intervention trials showed significantly higher values for DSST number of correct responses (with a difference of mean [SD], 1.2 [3.2], paired t-test, p = 0.035). Variables in the intervention trials were otherwise similar to those in the control trials for DSST number of incorrect responses, 2-BACK, and the Grooved Pegboard test.Conclusions and relevanceThis randomized clinical trial found that oxygen supplementation improves cognitive performance among HEMS providers during acute exposure to 4000 m altitude. The use of oxygen supplementation may allow to maintain attention and timely reaction in HEMS providers. The impact of repeated altitude ascents on the same day, sleep-deprivation, and additional stressors should be investigated.Trial registration NCT05073406, ClinicalTrials.gov trial registration.

40Ar diffusion in phlogopite: [formula omitted] atomistic calibration and implications for Ar–melt–solid kinetic interactions and ascent dynamics of mantle xenoliths and kimberlites

40Ar/39Ar ages of phlogopite from kimberlite-hosted mantle xenoliths are commonly older than the kimberlite eruption, despite the fact that argon is supposed not to be retained by phlogopite at temperatures above hydrothermally-derived Ar closure temperatures (<500°C). Combining Molecular Dynamics (MD) with Nudged Elastic Band (NEB) and Transition State Theory (TST), we investigate 40Ar−PVT (Pressure−Volume−Temperature) relationships in pristine, defect-free, phlogopite and show that 40Ar diffusivity is several orders of magnitude slower than existing estimates with a strong effect of pressure on diffusion rates and retention of 40Ar at mantle conditions. These results imply to fundamentally revise residence- and transit-time estimates based on Ar kinetics in phlogopite assuming simple diffusive relaxation during upwelling. When accounting for pressure, 40Ar retention trends in phlogopite predict substantially slower kimberlite ascent rates than documented by independent chronometers, indicating that 40Ar resetting during ascent in phlogopite does not result from simple decompression-driven diffusive relaxation. We argue that 40Ar remobilization probably involves secondary structural–textural modifications induced by reaction-driven recrystallization or rim overgrowth. These findings have far-reaching consequences in terms of argon isotopic mobility at mantle depths as well as for dating and tracing metasomatic events during crust−mantle interactions in the evolution of the subcontinental mantle.

Stratospheric balloon dynamics predictions for robust ascent phase payload thermal analysis

Stratospheric balloons are platforms with great relevance in space missions to reach scientific observations. The payload thermal analyses of such missions are usually focused on the float phase. However, during the ascent phase, the coolest temperatures of the entire mission may be reached, mainly due to the convective cooling in the tropopause. This can be explained by the combination of relative wind speed and the harsh thermal environment. The aim of this work is to evaluate the impact of the thermal environment on the relative wind speed to determine the worst-case thermal analysis. Therefore, in order to perform a robust payload thermal during the ascent phase, the uncertainty in the thermal environment and the relative velocity must be evaluated. The former are reduced by defining the thermal environment based on real-data. The latter are reduced by evaluating the parameters involved in the ascent rate. For this purpose, a dynamic model has been developed to characterise the ascent rate and the horizontal relative velocity of the balloon-borne system. This tool has been validated with flight data from the REXUS/BEXUS programme, with the BEXUS missions launched from Esrange, Kiruna, Sweden from 2014 to 2018. The thermal analysis performed shows a temperature difference greater than 10 °C depending on the thermal worst-case selection. The work here presented reduces the uncertainties of the stratospheric payloads ascent phase thermal analysis.

Relative Severity of Human Performance Decrements Recorded in Rapid vs. Gradual Decompression.

INTRODUCTION: Cabin decompression presents a threat in high-altitude-capable aircraft. A chamber study was performed to compare effects of rapid (RD) vs. gradual decompression and gauge impairment at altitude with and without hypoxia, as well as to assess recovery.METHODS: There were 12 participants who completed RD (1 s) and Gradual (3 min 12 s) ascents from 2743-7620 m (9000-25000 ft) altitude pressures while breathing air or 100% O₂. Physiological indices included oxygen saturation (SPo₂), heart rate (HR), respiration, end tidal O₂ and CO₂ partial pressures, and electroencephalography (EEG). Cognition was evaluated using SYNWIN, which combines memory, arithmetic, visual, and auditory tasks. The study incorporated ascent rate (RD, gradual), breathing gas (air, 100% O₂) and epoch (ground-level, pre-breathe, ascent-altitude, recovery) as factors.RESULTS: Physiological effects in hypoxic "air" ascents included decreased SPo₂ and end tidal O₂ and CO₂ partial pressures (hypocapnia), with elevated HR and minute ventilation (<mml:math id="im1" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>E); SPo₂ and HR effects were greater after RD (-7.3% lower and +10.0 bpm higher, respectively). HR and <mml:math id="im2" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>E decreased during recovery. SYNWIN performance declined during ascent in air, with key metrics, including composite score, falling further (-75% vs. -50%) after RD. Broad cognitive impairment was not recorded on 100% O₂, nor in recovery. EEG signals showed increased slow-wave activity during hypoxia.DISCUSSION: In hypoxic exposures, RD impaired performance more than gradual ascent. Hypobaria did not comprehensively impair performance without hypoxia. Lingering impairment was not observed during recovery, but HR and <mml:math id="im3" display="inline"><mml:mrow><mml:mover><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:mrow></mml:math>E metrics suggested compensatory slowing following altitude stress. Participants' cognitive strategy shifted as hypoxia progressed, with efficiency giving way to "satisficing," redistributing effort to easier tasks.Beer J, Mojica AJ, Blacker KJ, Dart TS, Morse BG, Sherman PM. Relative severity of human performance decrements recorded in rapid vs. gradual decompression. Aerosp Med Hum Perform. 2024; 95(7):353-366.

Influence of non-valve metal phase on growth behavior and performance of PEO coating on Mg–Zn–Mn alloys with high Mn content

The influence of pure metal phases (precipitation or reinforcement phases) on the PEO discharge and coating growth in Mg alloys remains underexplored. This study investigated the effects of the α-Mn phase on voltage evolution, coating morphology, phase composition, and corrosion resistance by subjecting Mg–4Zn-xMn (x = 0, 0.6, 1.2, 2.4 wt%) alloys to PEO treatment in alkaline silicate-based electrolyte. Results indicate that the presence of α-Mn does not prevent spark discharge. However, an increase in α-Mn content leads to a downward shift in the voltage-time curve. The α-Mn phase significantly slows down the voltage ascent rate and prolongs the duration of Stages I to III of PEO process. Electrochemical oxidation of the surrounding Mg matrix by the α-Mn phase induces the formation of pits and porous local morphologies, exacerbating coating unevenness. With the increasing in Mn content, the thickness and porosity of PEO coatings gradually decrease for the same treatment time. The coated Mg–4Zn-1.2Mn alloy exhibits the highest corrosion resistance. The differences in oxidizability between the α-Mn phase and the Mg matrix, as well as the stability and dielectric properties of the oxide products may be the underlying reasons for these effects. Despite Mn oxides' instability under alkaline conditions at high potentials, reaction products with the electrolyte offset this drawback. This study enhances understanding of pure metal phases' influence on Mg alloy PEO and contributes to research on PEO processes for Mg-based materials containing pure metal phases.

Altitude illnesses.

Millions of people visit high-altitude regions annually and more than 80 million live permanently above 2,500 m. Acute high-altitude exposure can trigger high-altitude illnesses (HAIs), including acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Chronic mountain sickness (CMS) can affect high-altitude resident populations worldwide. The prevalence of acute HAIs varies according to acclimatization status, rate of ascent and individual susceptibility. AMS, characterized by headache, nausea, dizziness and fatigue, is usually benign and self-limiting, and has been linked to hypoxia-induced cerebral blood volume increases, inflammation and related trigeminovascular system activation. Disruption of the blood-brain barrier leads to HACE, characterized by altered mental status and ataxia, and increased pulmonary capillary pressure, and related stress failure induces HAPE, characterized by dyspnoea, cough and exercise intolerance. Both conditions are progressive and life-threatening, requiring immediate medical intervention. Treatment includes supplemental oxygen and descent with appropriate pharmacological therapy. Preventive measures include slow ascent, pre-acclimatization and, in some instances, medications. CMS is characterized by excessive erythrocytosis and related clinical symptoms. In severe CMS, temporary or permanent relocation to low altitude is recommended. Future research should focus on more objective diagnostic tools to enable prompt treatment, improved identification of individual susceptibilities and effective acclimatization and prevention options.

Research on Anti-Rollover Adaptive Landing Gear Technology Based on Impedance Control

During the Vertical Take-Off and Landing (VTOL) of a rotorcraft, there is a high risk of instability and safety incidents due to the possibility of one side of the landing gear making initial contact with the ground, particularly under extreme environmental conditions and maneuvers. Furthermore, the varied performance of adaptive landing gear necessitates a landing control approach that specifically targets both sides of the adaptive landing gear. This study proposes a method that regulates the landing gear first touchdown side through an impedance controller to guarantee the stability of the rotorcraft and then tilts the landing gear toward the rear landing leg side, followed by a soft and smooth landing through the rear landing leg. This approach accomplishes steady adaptive VTOL of the rotorcraft. The fall vibration test results demonstrate that the adaptive landing gear system with impedance control has excellent adaptive landing functionality, which can handle not only landing on uneven ground at various points but also cope with different ascent rates and ground friction during stable takeoff/landing.

Shallow- and deep-convection characteristics in the greater Houston, Texas, area using cell tracking methodology

Abstract. The convective lifecycle, from initiation to maturity and dissipation, is driven by a combination of kinematic, thermodynamic, microphysical, and radiative processes that are strongly coupled and variable in time and space. Weather radars have been traditionally used to provide various convective-cloud characteristics. Here, we analyzed climatological convective-cell radar characteristics to obtain and assess the diurnal cycles of three convective-cell types – shallow, modest deep, and vigorous deep convective cells – that formed in the greater Houston area, using the National Weather Service radar from Houston, Texas, and a multi-cell identification and tracking algorithm. The examined dataset spans 4 years (2018–2021) and covers the warm-season months (June to September) in those years. The analysis showed clear diurnal cycles in cell initiation (CI) consistent with the sea breeze circulation and showed diurnal and normalized lifetime relationships in cell evolution parameters (e.g., maximum reflectivity, echo-top height, Geostationary Operational Environmental Satellite-16 (GOES-16) channel 13 brightness temperature, and the height of maximum reflectivity). The cell evolution is well represented by relationships between (1) the height and value of the maximum radar reflectivity, (2) the minimum GOES-16 channel 13 brightness temperature and the maximum vertically integrated liquid, (3) the maximum reflectivity and columnar-average reflectivity, and (4) the echo-top ascent rate and cell lifetime. The relationships presented herein help to identify the cell lifecycle stages such as early shallow convection, vigorous vertical development, anvil development, and convective core dissipation. GOES-16 Aerosol Optical Depth values are also used as a proxy for cell initiation aerosol concentrations to investigate any potential relationships between initiation location and aerosol concentration. Overall, no significant relationships between initiation location and aerosol concentration were found for the three cell types investigated, but there are some minor differences in the pre-CI aerosol optical depth for vigorous deep convective cells.

Evaluation and Management of the Individual with Recurrent High Altitude Pulmonary Edema.

Luks AM, Grissom CK. Evaluation and Management of the Individual with Recurrent HAPE. High Alt Med Biol. 25:238-246, 2024. Individuals with a history of acute altitude illness often seek recommendations from medical providers on how to prevent such problems on future ascents to high elevation. Although many of these cases can be managed with pharmacologic prophylaxis and counseling about the appropriate rate of ascent alone, there are some situations in which further diagnostic evaluation may also be warranted. One such situation is the individual with recurrent episodes of high altitude pulmonary edema (HAPE), as one of several predisposing factors may be present that warrants additional interventions beyond pharmacologic prophylaxis and slow ascent and may even preclude future travel to high altitude. This review considers this situation in greater detail. Structured around the case of an otherwise healthy 27-year-old individual with recurrent episodes of HAPE who would like to climb Denali (6,190 m), the review examines the known risk factors for disease and then provides guidance regarding when and how to evaluate such individuals and appropriate steps to prevent HAPE on further ascents to high elevation. Except in rare circumstances, a history of recurrent HAPE does not preclude further ascent to high elevation, as a multipronged approach including pharmacologic prophylaxis, careful planning about the rate of ascent, and the degree of physical effort and other strategies, such as preacclimatization, staged ascent, and use of hypoxic tents, can be employed to reduce the risk of recurrence with future travel.

Warm conveyor belt characteristics and impacts along the life cycle of extratropical cyclones: case studies and climatological analysis based on ERA5

Abstract. This study presents a systematic investigation of the characteristics and meteorological impacts of warm conveyor belts (WCBs). For this purpose, we compile a new WCB climatology (1980–2022) of trajectories calculated with the most recent reanalysis dataset ERA5 from the European Centre for Medium-Range Weather Forecasts (ECMWF). Based on this new climatology, two-dimensional masks are defined that represent the inflow, ascent, and outflow locations of WCBs. These masks are then used to objectively quantify the key characteristics (intensity, ascent rate, and ascent curvature) and meteorological impacts (precipitation and potential vorticity (PV) anomalies) of WCBs in order to (i) attribute them to different stages in the life cycle of the associated cyclones and to (ii) evaluate differences in the outflow of the cyclonic and anticyclonic branches. The approach was applied globally, but this study focuses on the North Atlantic, one of the regions where WCBs ascend most frequently. The method is first tested and illustrated through three case studies of well-documented cyclones, revealing both the similarities and the case-to-case variability in the evolution of the WCB characteristics and impacts. We then extend the analysis to about 5000 cyclones that occurred in winter between 1980–2022 in the North Atlantic. The case studies and the climatological analysis both show that WCBs are typically most intense (in terms of air mass transported, ascent rate, precipitation rate, and volume) during the intensification period of the associated cyclone. The northward displacement along the storm track and diabatic PV production lead to an increase in low-level PV in the region of WCB ascent during the cyclone life cycle. The negative PV anomaly at upper levels, associated with the WCB outflow, remains relatively constant. The investigation of the WCB branches reveals an increasing intensity of the cyclonic WCB branch with time, linked to the increasing strength of the cyclonic wind field around the cyclone. Due to a lower altitude, the outflow of the cyclonic WCB branch is associated with a weaker negative PV anomaly than the anticyclonic one, which ascends to higher altitudes. In summary, this study highlights the distinct evolution of WCB characteristics and impacts during the cyclone life cycle and the marked differences between the cyclonic and anticyclonic branches.

Melt inclusions in spinel from a composite mantle xenolith

Composite mantle xenoliths from the Cima Volcanic Field (CA, USA) contain a variety of melt (now glassy) inclusions hosted within mantle phases. The compositions and textures of these melt inclusions have the potential to constrain their trapping processes, melt sources, and the rates of ascent of their parent xenoliths. Here we focus on unusual spinel-hosted melt inclusions from one composite xenolith, reporting glass and daughter mineral compositions and textures and attempting to reconstruct inclusion bulk compositions. The xenolith contains spinel-hosted melt inclusions in its harzburgite, olivine-websterite and lherzolite layers; there are none in its orthopyroxenite layer.The glass compositions and reconstructed bulk compositions of the partly-crystallized inclusions correspond to alkaline intermediate melts, mostly trachyandesites. Such melts are most likely to be generated and trapped by vapor-undersaturated phlogopite or amphibole dehydration melting to an assemblage of liquid + spinel + olivine ± pyroxenes. We modeled the near-liquidus phase relations of the inclusion bulk compositions and noted the closest approach of each inclusion to simultaneous saturation with spinel and either phlogopite or amphibole, resulting in estimated trapping pressures of ∼0.5–1.5 GPa and temperatures of ∼1000–1100 °C. The large size of the hosting spinel grains suggests a slow process associated with these breakdown reactions, probably thinning of the lithosphere and steepening of the geotherm during regional extension.A linear correlation between the vesicle area and inclusion area (as proxies for volume) suggests an in-situ exsolution process from melts of relatively uniform volatile initial contents, consistent with trapping of vapor-undersaturated melts that later exsolve vapor during cooling and daughter crystal growth. A negative correlation between the glass content in melt inclusions and the size of the inclusion itself suggests a control on the degree of crystallinity with the size. There appears to be a two-stage cooling history captured by the inclusions, forming first prismatic daughter crystals and large round vesicles at the wall of the inclusion, followed by quenching to form a mat of fine crystallites and small vesicles in most inclusions. We connect the final quench to rapid ascent of the xenolith in its host melt, which also triggered partial breakdown of remaining amphibole to fine glassy symplectites.

Applications of Ground-Based Infrared Cameras for Remote Sensing of Volcanic Plumes

Ground-based infrared cameras can be used effectively and safely to provide quantitative information about small to moderate-sized volcanic eruptions. This study describes an infrared camera that has been used to measure emissions from the Mt. Etna and Stromboli (Sicily, Italy) volcanoes. The camera provides calibrated brightness temperature images in a broadband (8–14 µm) channel that is used to determine height, plume ascent rate and volcanic cloud/plume temperature and emissivity at temporal sampling rates of up to 1 Hz. The camera can be operated in the field using a portable battery and includes a microprocessor, data storage and WiFi. The processing and analyses of the data are described with examples from the field experiments. The updraft speeds of the small eruptions at Stromboli are found to decay with a timescale of ∼10 min and the volcanic plumes reach thermal equilibrium within ∼2 min. A strong eruption of Mt. Etna on 1 April 2021 was found to reach ∼9 km, with ascent speeds of 10–20 ms−1. The plume, mostly composed of the gases CO2, water vapour and SO2, became bent over by the prevailing winds at high levels, demonstrating the need for multiple cameras to accurately infer plume heights.

Magma residence time, ascent rate and eruptive style of the November ash-laden activity during the 2021 Tajogaite eruption (La Palma, Spain)

We combined compositional analyses, crystal size distributions and geothermobarometry of tephra erupted during the 2021 Tajogaite eruption (La Palma, Spain), focusing on samples collected in November 2021 associated with a period of abundant ash emission characteristic of the second half of the eruption (from October onwards). Magma erupted in November exhibits a more primitive basanitic composition than the earlier magma. Crystallisation temperatures range between ~1100–1160 °C (H2O = 1–3 wt.%) for phenocrysts and microphenocrysts, with corresponding pressures indicating depths from ~10 to ~30 km. Crystal size distribution analysis reveals short (minutes) residence times for plagioclase. Finally, magma ascent velocities (~0.01–0.3 m s−1) suggest acceleration and fragmentation in the shallowest part of the conduit. Our results suggest that the trigger of the November explosive activity can be attributed to complex feedback between gas emission rates, changes in conduit geometry, and magma ascent rate.

The role of magma ascent rates and viscosity in explosive and dome eruptions (Kelud volcano, Indonesia)

The role of magma ascent rates and viscosity in explosive and dome eruptions (Kelud volcano, Indonesia)

Evaluation of vertical transport in ERA5 and ERA-Interim reanalysis using high-altitude aircraft measurements in the Asian summer monsoon 2017

Abstract. During the Asian monsoon season, greenhouse gases and pollution emitted near the ground are rapidly uplifted by convection up to an altitude of ∼ 13 km, with slower ascent and mixing with the stratospheric background above. Here, we address the robustness of the representation of these transport processes in different reanalysis data sets using ERA5, ERA-Interim and ERA5 1∘×1∘. This transport assessment includes the mean age of air from global three-dimensional simulations by the Lagrangian transport model CLaMS (Chemical Lagrangian Model of the Stratosphere), as well as different trajectory-based transport times and associated ascent rates compared with observation-based age of air and ascent rates of long-lived trace gases from airborne measurements during the Asian summer monsoon 2017 in Nepal. Our findings confirm that the ERA5 reanalysis yields a better representation of convection than ERA-Interim, resulting in different transport times and air mass origins at the Earth's surface. In the Asian monsoon region above 430 K, the mean age of air driven by ERA-Interim is too young, whereas the mean age of air from ERA5 1∘×1∘ is too old but somewhat closer to the observations. The mean effective ascent rates derived from ERA5 and ERA5 1∘×1∘ back trajectories are in good agreement with the observation-based mean ascent rates, unlike ERA-Interim, which is much faster above 430 K. Although a reliable CO2 reconstruction is a challenge for model simulations, we show that, up to 410 K, the CO2 reconstruction using ERA5 agrees best with high-resolution in situ aircraft CO2 measurements, indicating a better representation of Asian monsoon transport in the newest ECMWF reanalysis product, ERA5.

Ascent of volatile-rich felsic magma in dykes: a numerical model applied to deep-sourced porphyry intrusions

SUMMARY Dyke propagation is a mechanism for more rapid ascent of felsic magmas through the crust than is possible via diapirs or percolative flow. As it ascends, the magma undergoes complex physical and chemical transformations induced by decompression and cooling. These processes dramatically change the magma density and viscosity, which in turn affect magma ascent rate and the depth at which the dyke arrests. We present a mathematical model of dyke propagation for silicic magmas taking into account the presence of multiple volatile species (H2O and CO2), bubble growth, heat advection and loss, crystallization and latent heat release. We consider conditions for dykes associated with porphyry ore deposits, which may represent an end-member in rapid ascent of felsic magmas from depth. In particular, we simulate the propagation of dykes launched from a deep (900 MPa), volatile-saturated magma source, testing the effects of the magma H2O/CO2 content, temperature and mass on its ascent rate and final emplacement depth. The model predicts short ascent times (hours to days), with a large increase in viscosity at shallow depth, leading to stagnation and solidification of the dyke. Higher initial water content, higher temperature and larger mass of the magma in the dyke promote faster propagation and shallower arrest. Volatile loss from ascending magma remains limited until the stagnation depth, providing a potential mechanism for transfer of deep volatiles to hypabyssal blind intrusions associated with porphyry ore deposits. Our findings are applicable to the problem of silicic magma ascent through the crust more generally.

Development and research of the effectiveness of using an automated aquaponic system for home cultivation of microgreens

In this study, an automated system was developed for the home cultivation of microgreens using aquaponics technology using modern technologies and a review of literary sources. The researcher was convinced that the automation system of the aquafarm is able to significantly simplify human care of the aquarium. Experimentally, the advantage of using this system over the "classic" method of growing microgreens, in terms of the rate of ascent of the stems, was tested. It was also verified that the developed automated system for a home aquapon installation has a positive effect on the biological ecosystem. Monitoring of the main indicators of water quality has shown sufficient effectiveness of this method to neutralize indicators such as nitrates. In the future, this work can become the basis for conducting a large number of experiments for longer periods and monitoring a wide range of water quality indicators and growing large types of seeds.

Precipitation Efficiencies in a Climatology of Southern Ocean Extratropical Cyclones

AbstractPrecipitation efficiency refers to the amount of water that is lost from the atmosphere through precipitation compared to the available water vapor in the atmosphere. This metric plays a critical role in understanding precipitation patterns. However, calculating precipitation efficiency for extratropical cyclones can be challenging because cyclones are dynamic and move through the atmosphere as they evolve. To overcome this challenge, our study uses ERA5 reanalysis data to estimate precipitation efficiencies for 400 Southern Ocean cyclones, with a frame of reference that moves with the individual cyclones. Our findings indicate that at maximum intensity, average precipitation efficiencies reach a maximum of 60%/6 hr near the warm front where ascent rates are the largest. Typically, within 24–36 hr after cyclogenesis, all of the initial water vapor available within 500 km of a cyclone center is lost due to precipitation. However, a cyclone's precipitating phase is prolonged due to local evaporation and moisture flux convergence (MFC), which replenish the moisture lost via precipitation. Close to the cyclone center, MFC provides additional moisture from the environment into which cyclones are traveling. On average, this extends a cyclone's precipitation phase to over 60 hr after cyclogenesis. Thus, while moisture from the genesis location is quickly removed from the cyclone via precipitation, cyclones are replenished by moisture along their track, which doubles the timescale for a cyclone's precipitating phase.