Rain Showers Research Articles

Chemical characteristics of BTEX, Formaldehyde and Trace gases: concentration, ozone formation potential and source apportionment at a campus site of Agra.

Benzene, toluene, ethylbenzene, xylenes (BTEX) and formaldehyde (HCHO) impact the environment and human health due to their deleterious effect and are of great concern. In the present study, diurnal and seasonal trend of BTEX and HCHO along with trace gases are reported. BTEX samples were collected by activated charcoal tubes and analysed by Gas Chromatograph coupled with Mass Spectrometer and Flame Ionization Detector (GC-MS/FID) and formaldehyde sampling was done by impinger method and analysed by UV-Visible Spectroscopy. Summation BTEX varied from 50.3 to 188.3µgm-3 (average = 74.8 ± 31.8µgm-3). Amongst all species, toluene was the most abundant. Highest levels of BTEX, NOx and CO were observed in winter (96.4 ± 39.1µgm-3, 11.9 ± 7.8ppb and 540.8 ± 402.0ppb respectively) probably due to enhanced local emissions, stagnant weather conditions resulting in dilution and dispersion of pollutants and weak photochemical removal. Lower values are seen during monsoon (58.6 ± 25.4µgm-3, 7.6 ± 6.1µgm-3 and 149.8 ± 68.7µgm-3) as a consequence of rain showers and washout effect leading to clean atmospheric conditions. Further, ozone forming potential (OFP) BTEX was determined based on their reactivity with OH˙radical and concentration. Toluene (90.9µgm-3) was the largest contributor to ozone formation, whereas benzene (9.1µgm-3) was the lowest. Source apportionment of BTEX was determined based on estimation of diagnostic ratios, correlations and positive matrix factorization (PMF) analysis and revealed emissions from vehicles was the main source. Air mass back trajectory analysis for different seasons shows the impact of long-range during the summer season and localized air masses during winter season. The results of the current study provide a better understanding of OFP and sources of BTEX and HCHO to formulate effective pollution management.

Assessment of Association Between Observed Weather and Detrended Weather with the Detrended Rice Crop Yield in the Konkan Region of Maharashtra

Maharashtra’s total rice production (1961-2014) strongly increases. This is due to the increasing cultivated area and the influence of improved technology. Whereas, year-to-year fluctuation in production is mainly because of fluctuations in the climate. Hence, only the rice crop yield is taken for the detailed study of climate and agriculture in the selected districts from 1981 to 2014 period. Correlation analysis indicates the influence of climate change on detrend yield. A heavy shower of rain and hail can cause immense damage to a standing crop, ready for harvest (Crop weather calendar 2003, IMD). Thus, yield is the summation of conditions in all successive weeks of the crop. Correlation analysis was carried out to see the impact of observed weather with detrend yield and detrended weather with detrend yield. The Research Work explores the importance of additional Climatic variables, other than Temperature and Rainfall, and their impact on Rice crop yield. There is a significant relationship between the Observed Weather Parameter and De-trended Weather Parameter with the De-trend Yield, at different Growth Stages of Crop. The study brought about the Relationship between Rice Crop Yield and Weather Parameters, with and without Climate Change.

3D Printing of Flow Profiles for Inspection Chambers and Manholes

For years the way of producing a flow profile for Inspection Chambers and Manholes could be divided into 3 methods: Injection moulding, Roto moulding and Hand assembling. For the standard orientations, for example straight through and cross, the IM profile integrated with a base is by far the best option. But for nonstandard configurations; different orientations, inlet heights and inlet sizes, the only option is to hand weld them together from injection moulded parts, pipes and plates. This is a time- consuming way of producing with high production cost and often aesthetic-wise of a challenging level. This is not necessary anymore after the introduction of 3D printing as a new production method for flow profiles in chambers and manholes. 3D printing is in many industries an accepted production method which can produce parts of high quality and high accuracy. The printing systems have faced a huge development in the last 10 years and prints are often close to perfection. The only disadvantage of these printing systems is the maximum size of the print. But since the introduction of 3D robot printing, products with a diameter of 1 meter can be printed without any problem. 3D robot printers were up to recently, used for prototypes, one- off products and art objects. Now a production area is created on which multiple products can be produced in a row without human interference. The most common materials used for 3D printing are ABS and PLA. These materials have good adhesion, almost no shrinkage and a good appearance. Unfortunately, these materials are not common in our industry. We need PP, PE or PVC. While our manholes and inspection chambers are from PP, we also need PP flow profiles. The advantage of using a 3D robot printer is that it uses granulates instead of filaments or special powder. This makes the material cost part almost equal to injection moulding. Another advantage is also that recycled material can be used. Own scrap can be used but also waste from other markets. The main reason that flows profiles are ideal for 3D printing is that nonstandard flow profiles are very labour-intensive. So, 3D printing really helps out here. Besides that, there is a lot of freedom in design. This helps to design in such a way, that the final profile is hydraulically optimal. This prevents the overflowing of manholes during heavy rain showers. Of course, these products should fulfil all requirements of the EN13598-2. Even though major development steps have been made in 3D printing during the last 5 years, 3D robot printing is still in the exploring phase and we find many hurdles on our way. This paper will show how our industry can use 3D printing and what are the pros and cons.

Spectroscopic Observations of Coronal Rain Formation and Evolution Following an X2 Solar Flare

A significant impediment to solving the coronal heating problem is that we currently only observe active region loops in their cooling phase. Previous studies showed that the evolution of cooling loop densities and apex temperatures is insensitive to the magnitude, duration, and location of energy deposition. Still, potential clues to how energy is released are encoded in the properties of the cooling phase. The appearance of coronal rain, one of the most spectacular phenomena of the cooling phase, occurs when plasma has cooled below 1 MK, which sets constraints on the heating frequency, for example. Most observations of coronal rain have been made by imaging instruments. Here we report rare Hinode/EUV Imaging Spectrometer (EIS) observations of a loop arcade where coronal rain forms following an X2.1 limb flare. A bifurcation in plasma composition measurements between photospheric at 1.5 MK and coronal at 3.5 MK suggests that we are observing postflare-driven coronal rain. Increases in nonthermal velocities and densities with decreasing temperature (2.7–0.6 MK) suggest that we are observing the formation and subsequent evolution of the condensations. Doppler velocity measurements imply that a 10% correction of apparent flows in imaging data is reasonable. Emission measure analysis at 0.7 MK shows narrow temperature distributions, indicating coherent behavior reminiscent of that observed in coronal loops. The limitations on spatio-temporal resolution of EIS suggest that we are observing the largest features or rain showers. These observations provide insights into the heating rate, source, turbulence, and collective behavior of coronal rain from observations of the loop cooling phase.

Substantiation of source data on the parametric algorithms for the classification of weather hazards

The meteorological situation is one of the decisive factors determining the safety and frequency of civil aviation flights. Weather hazards (WH), associated with cumulonimbus clouds, such as a heavy shower, thunderstorm, hail, combined with high atmosphere turbulence, quite often lead to aviation events and even accidents. Currently, a domestic weather radar system of the near airfield zone (WR) “Monocle” has been developed and successfully operated. The criteria for the classification of meteorological phenomena (MP), used in the WR, have been developed individually for each phenomenon and have some heuristic character. These criteria are cumbersome and complicate the process of automating the WH classification. In this case, there is a natural desire to generalize the criteria and optimize them in accordance with the theory of distinguishing statistical hypotheses. This article discusses the application of the Bayesian approach to the WH classification. The statistical Bayesian decision theory assumes decision-making in terms of the probability theory when all significant probabilistic values, so-called sufficient statistics, are known. In order to obtain statistical descriptions of the probability distributions of reflectivity and the eddy dissipation rate (EDR), an analysis of radar signals, reflected from such MP as a rain shower, thunderstorm, hail was carried out. The article provides brief descriptions of the methods of conducting experiments to form statistical database and its analysis. Based on the above methods, the statistical parameter H(EDRmax) analysis for a rain shower, the amplitude distribution of reflectivity parameters and the EDR (Zmax, EDRmax) for thunderstorms and hail was carried out, which showed the low distinguishing ability of each individual parameter when solving the problem to classify MP within the assigned alphabet. The obvious solution is dictated by the theory of recognition. To increase the classification confidence, it is essential to share information parameters, for example, in the form of multidimensional distribution densities of the probabilities of random parameters. The article presents a parametric description of the MP “rain shower-thunderstorm-hail” classification features. An analysis to evaluate the probabilistic characteristics of the WH classification for the adopted empirical classification criteria in the WR shows that the adopted criteria are far from optimal in terms of the probabilities of the correct classification, especially in the rain shower case. It is obvious that a problem solution of the assigned classification confidence is associated with the optimization of the feature space and classification criteria. Based on the data obtained, it is necessary to build an algorithm to classify the WH “rain shower-thunderstorm-hail”.

A case study of an extreme flooding episode in Charikar, Eastern Afghanistan

Abstract This work investigates the meteorological mechanisms forming a classical frontal system on 26 August 2020 in the northeast and eastern parts of Afghanistan. The weather system caused heavy rainfall and led to severe flash floods. Flooding, affected by torrential rain showers, struck mostly the city of Charikar in Parvan province early in the morning day, while most people were asleep. This caused 150 deaths, and nearly 500 houses were destroyed. This research explores atmospheric processes by examining the National Centers for Environmental Prediction dataset and MERRA Model database. The calculation of the convective available potential energy (CAPE) and Showalter index extracted from the Skew-T log-pressure diagram shows a high value of the CAPE at around 2,632 J/kg and −6.6 for the Showalter index, respectively. This presents a very extreme instability in the study area during the time of the flood. The study reveals that the triggering of this system was mostly by thermodynamical aspects, low-level deep convergence, and local topographical aspects rather than the PV streamer. However, the anomaly climate analysis for different atmospheric elements with a comparison of the climate normal values shows the importance of climate change in the weather system into a stronger frontal activity associated with stronger baroclinicity over the study area.

Experimental statistical analysis of radar signals reflected from weather hazards

The nature of the causes of prerequisites for flight accidents due to meteorological conditions has remained unchanged for many years. For the effective operation of aviation, it is necessary to solve the issues of the timely detection of weather hazards and the identification of their intensity. This article discusses the research into the atmospheric reflectivity and turbulence in cumulonimbus clouds using a near-field meteorological radar system. Experimental studies are carried out with the aim of obtaining estimates of statistical characteristics of the reflectivity distribution and turbulence for weather hazards. The methodology for conducting an experimental study to obtain information about the weather hazards (rain shower, thunderstorm and hail), special features of the radar reflectivity propagation and the specific rate of turbulent energy dissipation in the considered conditions for the Tver region is presented. The analysis of the obtained results has been carried out: comparisons of meteorological data derived, using the meteorological radar complex of the near airfield zone (WR BZ), with the reliable sources of meteorological observation data obtained during experimental studies. Studies of horizontal sections and vertical profiles of the weather hazards parameters under consideration, associated with the cumulonimbus area, have been carried out. A data bank has been formed. Histograms of the information parameter distribution have been constructed. The article considers the results of experimental data approximation, using the χ2 criterion for various distribution laws. It is shown that the distributions of reflectivity and turbulence can be described by the generalized Rice’s law. The results obtained can be used to correct the classification criteria of weather hazards to subsequently increase the justification and reliability of the weather hazard classification. The further development of the method to process meteorological information is also of paramount importance to more correctly interpretate experimental data processing results of remote meteorological phenomena sensing.

Flood Protection of the Non-Urban Area

Due to global warming, the risk of floods is constantly increasing due to the drying up of the soil, followed by more intense rain showers and storms. Therefore, it is essential to pay more attention to this topic now. The article deals with the design of flood protection in the municipality. A flood control measure is proposed for each type of slope of the soil relief in which the municipality is located. Based on the proposed measures, the article aims to minimize the level of flood risk to the lowest possible level with the use of flood protection aimed at the non-urban area of the municipality. The proposed measures are intended not only for smaller municipalities but also for cities.

Extreme-ultraviolet fine structure and variability associated with coronal rain revealed by Solar Orbiter/EUI HRIEUV and SPICE

Context. Coronal rain is the most dramatic cooling phenomenon of the solar corona. Recent observations in the visible and UV spectrum have shown that coronal rain is a pervasive phenomenon in active regions. Its strong link with coronal heating through the thermal non-equilibrium (TNE) – thermal instability (TI) scenario makes it an essential diagnostic tool for the heating properties. Another puzzling feature of the solar corona in addition to the heating is its filamentary structure and variability, particularly in the extreme UV (EUV). Aims. We aim to identify observable features of the TNE-TI scenario underlying coronal rain at small and large spatial scales to understand the role it plays in the solar corona. Methods. We used EUV datasets at an unprecedented spatial resolution of ≈240 km from the High Resolution Imager (HRI) in the EUV (HRIEUV) of the Extreme Ultraviolet Imager (EUI) and SPICE on board Solar Orbiter from the perihelion in March and April 2022. Results. EUV absorption features produced by coronal rain are detected at scales as small as 260 km. As the rain falls, heating and compression is produced immediately downstream, leading to a small EUV brightening that accompanies the fall and produces a fireball phenomenon in the solar corona. Just prior to impact, a flash-like EUV brightening downstream of the rain, lasting a few minutes, is observed for the fastest events. For the first time, we detect the atmospheric response to the impact of the rain on the chromosphere, and it consists of upward-propagating rebound shocks and flows that partly reheat the loop. The observed widths of the rain clumps are 500 ± 200 km. They exhibit a broad velocity distribution of 10 − 150 km s−1and peak below 50 km s−1. Coronal strands of similar widths are observed along the same loops. They are co-spatial with cool filamentary structure seen with SPICE, which we interpret as the condensation corona transition region. Prior to the appearance of the rain, sequential loop brightenings are detected in gradually cooler lines from coronal to chromospheric temperatures. This matches the expected cooling. Despite the large rain showers, most cannot be detected in AIA 171 in quadrature, indicating that line-of-sight effects play a major role in the visibility of coronal rain. The AIA 304 and SPICE observations still reveal that only a small fraction of the rain can be captured by HRIEUV. Conclusions. Coronal rain generates EUV structure and variability over a wide range of scales, from coronal loops to the smallest resolvable scales. This establishes the major role that TNE-TI plays in the observed EUV morphology and variability of the corona.

Bioinspired Scalable Lubricated Bicontinuous Porous Composites with Self-Recoverability and Exceptional Outdoor Durability.

Lubricant-impregnated surfaces (LIS) are promising as efficient liquid-repellent surfaces, which comprise a surface lubricant layer stabilized by base solid structures. However, the lubricant layer is susceptible to depletion upon exposure to degrading stimuli, leading to the loss of functionality. Lubricant depletion becomes even more pronounced in exposed outdoor conditions, restricting LIS to short-term lab-scale applications. Thus, the development of scalable and long-term stable LIS suitable for practical outdoor applications remains challenging. In this work, we designed "Lubricated Bicontinuous porous Composites" (LuBiCs) by infusing a silicone oil lubricant into a bicontinuous porous composite matrix of tetrapod-shaped zinc oxide microfillers and poly(dimethylsiloxane). LuBiCs are prepared in the meter scale by a facile drop-casting inspired wet process. The bicontinuous porous feature of the LuBiCs enables capillarity-driven spontaneous lubricant transport throughout the surface without any external driving force. Consequently, the LuBiCs can regain liquid-repellent function upon lubricant depletion via capillary replenishment from a small, connected lubricant reservoir, making them tolerant to lubricant-degrading stimuli (e.g., rain shower, surface wiping, and shearing). As a proof-of-concept, we show that the large-scale "LuBiC roof" retains slippery behavior even after more than 9 months of outdoor exposure.

Cover Photograph

Front cover: Ominous thickening of Cumulonimbus cloud heralding a series of rain showers marking a minor trough line. Stratfield Mortimer, Berkshire, looking west‐southwest at 1506 utc on 30 April 2021. (© Stephen Burt.)image

Bulk Microphysical Characteristics of a Heavy-Rain Complex Thunderstorm System in the Taipei Basin

Abstract Severe rainfall has become increasingly frequent and intense in the Taipei metropolitan area. A complex thunderstorm in the Taipei Basin on 14 June 2015 produced an extreme rain rate (>130 mm h−1), leading to an urban flash flood. This paper presents storms’ microphysical and dynamic features during the organizing and heavy rain stages, mainly based on observed polarimetric variables in a Doppler radar network and ground-based raindrop size distribution. Shallower isolated cells in the early afternoon characterized by big raindrops produced a rain rate > 10 mm h−1, but the rain showers persisted for a short time. The storm’s evolution highlighted the behavior of merged convective cells before the heaviest rainfall (exceeding 60 mm within 20 min). The columnar features of differential reflectivity (ZDR) and specific differential phase (KDP) became more evident in merged cells, which correlated with the broad distribution of upward motion and mixed-phase hydrometeors. The KDP below the environmental 0°C level increased toward the ground associated with the melted graupel and resulted in subsequent intense rain rates, showing the contribution of the ice-phase process. Due to the collision–breakup process, the highest concentrations of almost all drop sizes and smaller mass-weighted mean diameter occurred during the maximum rainfall stage.

Quantifying the Lucky Droplet Model for Rainfall

It is difficult to explain rainfall from ice-free clouds, because the timescale for the onset of rain showers is shorter than the mean time for collisions between microscopic water droplets. It has been suggested that raindrops are produced from very rare ‘lucky’ droplets, which undergo a large number of collisions on a timescale which is short compared to the mean time for the first collision. This work uses large deviation theory to develop estimates for the timescale for the onset of a rain shower, as a function of the collision rate coefficients. The growth history of the fast-growing droplets which do become raindrops is discussed. It is shown that their first few collisions are always approximately equally spaced in time, regardless of how the mean time for collisions varies as a function of the number of collisions.

Rethinking Corporate Social Responsibility in the Arena of Climate Change: A Study in Socio-Legal Aspect

Climate change is an environmental challenge confronting all countries across the globe in varying degrees of intensity. It, directly and indirectly, interferes with the enjoyment of all human beings including – the right to life, housing, water and sanitation, food, health, development, security of persons and an adequate standard of living. Industry and business play a crucial role with regard to climate change, accounting for approximately one-third of the world’s energy consumption and 36 per cent of carbon dioxide emissions. Therefore, industry and the global business community have a responsibility to join national and international efforts to lower their greenhouse gas emissions. Across Asia, Europe, Africa, and North and South America, the adverse effects of climate change have manifested over the years as ozone layer depletion, continental global warming, a shower of acid rain, extended fires, melting ice, rise in sea level and other extreme events which call for urgent action at national and international levels. A self-regulating approach that makes manufacturing organisations socially responsible and responsive to environmental issues in their operating countries can be pragmatic in climate-change mitigation, and strengthen existing governmental policies on climate change. A number of affirmative actions and recommendations has been formulated at national and international levels to regulate climate change including eco-vigilance, adoption of green, conservation of the flora and fauna, zero-tolerance of gas flaring, socially responsible investment, carbon emission reporting and disclosures and adoption of environment-friendly manufacturing techniques. Therefore, the present study not only focusses on the theoretical aspect but also on the socio-legal aspect filling the gap in both theory and practice related to the impact of Corporate Social Responsibility on society.

The Winter’s Tale

Reviewed by: The Winter’s Tale Noel Sloboda The Winter’s Tale Presented by the Harrisburg Shakespeare Company at Reservoir Park, Harrisburg, PA. 3–18 June 2022. Directed by Clark Nicholson. Costume design by Jennifer Kilander. Movement by Kim Greenawalt. Scenic design by Andrew Nyberg. With Christopher Ellis (Camillo), Aaron Bomar/Philip Wheeler (Antigonus), Michael James Kacey/Clark Nicholson (Polixenes), F. L. Henley, Jr. (Leontes), Erika Eberly (Hermione), Zahar Georgievskiy (Mamillius), Jenni Chavis (Paulina), Jeff Wasileski (Shepherd), Josh Miccio (Clown), Joel Colvin (Autolycus), Jimmy Kohlmann (Florizel), Sydney Crutcher (Perdita), and others. From sirens to fireworks, from locusts to rain showers, unexpected challenges can seriously impact outdoor theater. This is something members of the Harrisburg Shakespeare Company know well after having put on twenty-eight previous productions at Reservoir Park. However, the primary challenges faced by the troupe on the evening I saw its latest version of The Winter’s Tale can happen both indoors and outdoors, and such challenges are far more likely to crop up during the era of COVID-19 than in years past. A preshow announcement stated that two regular cast members were unavailable due to illness. The role of Antigonus was to be [End Page 560] performed by stand-in Philip Wheeler (a regular in many Gamut productions), while the role of Polixenes was to be performed by the show’s director, Clark Nicholson. Wheeler was off book, with perfect blocking, and he inhabited the part of the Sicilian counselor as comfortably as if he had been rehearsing it for months. As the king of Bohemia, Nicholson needed to refer to a script—understandably, perhaps, since his attention had lately been occupied by coordinating everything else. Yet this minor distraction was easy to overlook given Nicholson’s confident delivery and contagious energy. Indeed, he even took part in a raucous dance that was part of a Bohemian sheep-shearing festival, kicking up his feet in a country jig while clutching a script to his breast. The rest of the cast came forward with comparable spirit and commitment, though some performers had better results than others. The first half of the show revolved around Leontes (F. L. Henley, Jr.), whose irrational wrath propelled the action forward. As the Sicilian king visited misery upon courtiers, confidantes, and family members, Henley presented Leontes as physically unwell. He suffered from a fever that made him wheeze, sweat, and mop his brow with a handkerchief, perhaps to suggest a physiological explanation for the king’s delusions about being cuckolded. It got so bad for Leontes that at one point he vomited and collapsed, remaining off his feet for several minutes. As the king’s illness worsened and his visions of infidelity grew more intense, his costume came undone: the monarch had lost his jacket and wore his shirt untucked by the time Hermione was to be judged by the oracle from Delphi. In another nice touch related to the appearance of Leontes, the “sword” he asked Antigonus to swear by (2.3.166) and jabbed in the air to punctuate rants was just a dagger. In fact, it looked very much like the dagger borne by his son Mamillius, played by a fourth grader (Zahar Georgievskiy). By implication, the monarch had the maturity level of a child and was far less in command than he believed, even if his delusions would have far-reaching consequences. Henley was not quite as successful in conveying nuance as ire. His tirades started at an extremely high pitch, infused with venom teetering on madness from the opening scenes. This gave him little room in which to maneuver or to develop his character. He was more successful in texturing the king in the second half of the play, when he conveyed a full range of emotions. After losing his son and wife, Leontes was subdued, replacing his sword (dagger) with a cane, diminished but now healthy, the fever burned out of him. Leontes was also plainly ashamed of what he had done, often hanging his head and keeping his voice low, though [End Page 561] he regained some animation at the recovery of his daughter and then his wife. For her part, Erika Eberly as Hermione...

An extraordinary dry season precipitation event in the subtropical Andes: Drivers, impacts and predictability

A major storm impacted the subtropical Andes during 28–31 January 2021 producing 4-days accumulated precipitation up to 100 mm over central-south Chile. These are high accumulations even for winter events but the storm occurred in the middle of the summer when precipitation is virtually absent, conferring it an extraordinary character. Similar storms have occurred only 2–3 times in the past century. The January 2021 event included periods of high rainfall intensity, hail and lighting, causing dozens of landslides and flash floods with the concomitant social impacts and economical losses. Here we examine the meteorological drivers of this storm at multiples scales, its climatological context, the associated surface impacts, and some aspects of its predictability.About a week before the storm development over central Chile, a large-scale perturbation in the central South Pacific set the stage for the formation of a zonal jet aloft and zonal atmospheric river (ZAR) that extended eastward until reaching the west coast of South America. The ZAR landfalled at 39°S and its subsequent northward displacement resulted in copious orographic precipitation over the Andes and adjacent lowlands, concomitant with a relatively warm environment during the first phase of the storm (28–29 January). During the second phase (30–31 January) the ZAR decayed rapidly but left behind significant amount of water vapor and the formation of a cut-off low (COL) in its poleward flank. The COL facilitated both advection of cyclonic vorticity and cold air at mid-levels, setting the environment for deep convection, intense rain showers, significant lightning activity, and hail.An assessment of the quantitative precipitation forecast (QPF) from the operational Global Forecast System (GFS) indicates that the model captured well the 96-h precipitation accumulation (28–31 January) in terms of timing and spatial extent. However, specific zones with the largest accumulations varied as a function of lead time. The more stable precipitation during the ZAR phase was better predicted than the convective precipitation during the COL phase. Proper dissemination of these forecast and recently established infrastructure contributed to ease the impact of this extraordinary event on the general population.

Usage of Atmospheric Sounding to Characterize the Meteorological Events on the Night of 23/24 August, 2022

Abstract At the end of summer, the episode of atmospheric instability in the Moldavia region, is attributed to the predominantly eastern circulation, which directed air masses from the Asian continent to Romania. This context is the result of the presence of a high-pressure area, located in northern Siberia and extended to north-eastern Europe. Romania was located in the flow of the eastern circulation, behind the warm front. The emersion of unforeseen factors, as was the case with the transport of dust from the dry regions of Asia, due to background of a circulation from the east, or the specificities of the relief, make it difficult to forecast the phenomena associated with instability. In this sense, atmospheric soundings are among the most used tools in forecasting atmospheric instability. In this sense, we used atmospheric soundings estimated by the GFS and ECMWF numerical forecast models to analyze the atmosphere vertically. Also, the cross-section profiles drawn in the EUMeTrain application showed the differences between the west and the east of Moldavia and described the vertical atmosphere in the analysed interval. The evolution of the convective episode was described through satellite images. The forecast models anticipated the instability but did not estimate the amounts of cumulative precipitation. The increase in the amount of precipitation was, among other things, attributed to the existence in the atmosphere of Moldavia of dust particles that acted as condensation nuclei that increased the amount of precipitation. High concentrations of dust were also noticed after consistent rain showers, as explained by Cloudnet data processed. The analysed case was one of the most representative instability episodes for summer of 2022 in Moldavia and played a decisive role in the soil water reserve. Here’s how air quality and changes in the atmosphere have a major impact on the environment. The notable frequency of detected electrical discharges, was probably also the result of the presence in the atmosphere of suspended dust particles (due to a natural air pollution process), driven towards the Moldavia region.

Prevalence of Thermal Nonequilibrium over an Active Region

Recent observations have shown that besides the characteristic multimillion degree component, the corona also contains a large amount of cool material called coronal rain, whose clumps are 10–100 times cooler and denser than the surroundings and are often organized in larger events, termed showers. Thermal instability (TI) within a coronal loop in a state of thermal nonequilibrium (TNE) is the leading mechanism behind the formation of coronal rain but no investigation on showers exists to date. In this study, we conduct a morphological and thermodynamic multiwavelength study of coronal rain showers observed in an active region (AR) off-limb with IRIS and the Solar Dynamics Observatory, spanning chromospheric to transition region and coronal temperatures. Rain showers were found to be widespread across the AR over the 5.45 hr observing time, with an average length, width, and duration of 27.37 ± 11.95 Mm, 2.14 ± 0.74 Mm, and 35.22 ± 20.35 minutes, respectively. We find a good correspondence between showers and the cooling coronal structures consistent with the TNE–TI scenario, thereby properly identifying coronal loops in the “coronal veil”, including the strong expansion at low heights and an almost zero expansion in the corona. This agrees with previous work suggesting that the observed zero expansion in the EUV is due to specific cross-field temperature distribution. We estimate the total number of showers to be 155 ± 40, leading to a TNE volume of 4.56 ± [3.71] × 1028 cm3, i.e., on the same order of the AR volume. This suggests a prevalence of TNE over the AR indicating strongly stratified and high-frequency heating on average.

A Network of X-Band Meteorological Radars to Support the Motorway System (Campania Region Meteorological Radar Network Project)

The transport sector and road infrastructures are very sensitive to the issues connected to the atmospheric conditions. The latter constitute a source of relevant risk, especially for roads running in mountainous areas, where a wide spectrum of meteorological phenomena, such as rain showers, snow, hail, wind gusts and ice, threatens drivers’ safety. In such contexts, to face out critical situations it is essential to develop a monitoring system that is able to capillary surveil specific sectors or very small basins, providing real time information that may be crucial to preserve lives and assets. In this work, we present the results of the “Campania Region Meteorological Radar Network”, which is focused on the development of X-band radar-based meteorological products that can support highway traffic management and maintenance. The X-band measurements provided by two single-polarization systems, properly integrated with the observations supplied by disdrometers and conventional automatic weather stations, were involved in the following main tasks: (i) the development of a radar composite product; (ii) the devise of a probability of hail index; (iii) the real time discrimination of precipitation type (rain, mixed and snow); (iv) the development of a snowfall rate estimator. The performance of these products was assessed for two case studies, related to a relevant summer hailstorm (which occurred on 1 August 2020) and to a winter precipitation event (which occurred on 13 February 2021). In both cases, the X-band radar-based tools proved to be useful for the stakeholders involved in the management of highway traffic, providing a reliable characterization of precipitation events and of the fast-changing vertical structure of convective cells.

Coronal Rain in Randomly Heated Arcades

Abstract Adopting the MPI-AMRVAC code, we present a 2.5-dimensional magnetohydrodynamic simulation, which includes thermal conduction and radiative cooling, to investigate the formation and evolution of the coronal rain phenomenon. We perform the simulation in initially linear force-free magnetic fields that host chromospheric, transition-region, and coronal plasma, with turbulent heating localized on their footpoints. Due to thermal instability, condensations start to occur at the loop top, and rebound shocks are generated by the siphon inflows. Condensations fragment into smaller blobs moving downwards, and as they hit the lower atmosphere, concurrent upflows are triggered. Larger clumps show us clear coronal rain showers as dark structures in synthetic EUV hot channels and as bright blobs with cool cores in the 304 Å channel, well resembling real observations. Following coronal rain dynamics for more than 10 hr, we carry out a statistical study of all coronal rain blobs to quantify their widths, lengths, areas, velocity distributions, and other properties. The coronal rain shows us continuous heating–condensation cycles, as well as cycles in EUV emissions. Compared to the previous studies adopting steady heating, the rain happens faster and in more erratic cycles. Although most blobs are falling downward, upward-moving blobs exist at basically every moment. We also track the movement of individual blobs to study their dynamics and the forces driving their movements. The blobs have a prominence-corona transition-region-like structure surrounding them, and their movements are dominated by the pressure evolution in the very dynamic loop system.