Altitude Distribution Research Articles

МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ПОВЕДЕНИЯ ВОЗДУШНЫХ ПОТОКОВ НА ТЕРРИТОРИИ ОТКРЫТЫХ УГОЛЬНЫХ СКЛАДОВ

The article discusses the need to use mathematical modeling to study the behavior of air flows in the territory of a port open coal warehouse. To study these processes of the interaction of the movement of air masses on the territory of the port with coal particles, the movement of a point volume of air in an arbitrary space of the air flow, which is inextricable, was considered. This approach allows to take into account all meteorological features of blowing more accurately: wind speed, altitude distribution of speeds, flow turbulization, various geometric parameters of the warehouse. As a result of the numerical implementation of this model by the control volume method, we get the opportunity to analyze the structure of the stream flowing around the coal warehouse and draw conclusions about the nature of dust formation, separation of coal dust particles, displacement of coal dust particles.

Quiet, Discrete Auroral Arcs—Observations

Quiet, discrete auroral arcs are an important and fundamental consequence of solar wind-magnetosphere interaction. We summarize the current standing of observations of such auroral arcs. We review the basic characteristics of the arcs, including occurrence in time and space, lifetimes, width and length, as well as brightness, and the energy of the magnetospheric electrons responsible for the optical emission. We briefly discuss the connection between single and multiple discrete arcs. The acceleration of the magnetospheric electrons by high-altitude electric potential structure is reviewed, together with our current knowledge of these structures. Observations relating to the potential drop, altitude distribution and lifetimes are reviewed, as well as direct evidence for the parallel electric fields of the acceleration structures. The current closure in the ionosphere of the currents carried by the auroral electrons is discussed together with its impact on the ionosphere and thermosphere. The connection of auroral arcs to the magnetosphere and generator regions is briefly touched upon. Finally we discuss how to progress from the current observational status to further our understanding of auroral arcs.

A New View of the Mass Extinctions and the Worldwide Floods

In this study, the reasons for mass extinction in Jurassic were investigated. It was shown that galactic compression led to the activation of terrestrial nuclear reactors, which in turn led to the changes in tectonic activity, volcano eruptions, LIPs, MORBs, paleoclimate change, drift of continents, narrowing of the Earth, worldwide floods, tsunami, changes in mantle and core structures, in magnetic fields and in sedimentary isotopes. It was shown that the mass extinctions occurred during worldwide floods, caused by the narrowing of the Earth at the time of galactic gravitational compression. It was shown that the average statistical altitude distribution of dinosaurs has a bimodal distribution and corresponds to permanent migrations between the plains and the hills. It has been suggested that the skeletons of dinosaurs are well preserved as a result of covering the bodies of dinosaurs with mud flows of coastal sediments and the soil layers at worldwide tsunami. It was formulated the requirement to paleontology, consisting in the obligatory registration of altitudes of the actual place of the fossils found. The simple explanation of the presence of boundaries in the structure of the Earth is given: the 40K nuclear layer corresponds to the boundary between upper and lower mantle; the 137Cs layer located on the boundary between the lower mantle and the outer core; the Th-U nuclear layer is a border between outer and inner core. The previously abstract theories of subduction and continents drift have a clear and obvious physical sense. It was shown that the standard geological table is a registration book of galactic events during Paleozoic. It is proposed to restore the structure of the galactic arms by the geological deposits on the Earth. It was suggested to create the stations on elevated hills for rescue and regeneration of biological forms in the future.

Altitude and Ecological distribution of genus Litsea (Lauraceae) in Western Ghats of Karnataka, India

India is a subcontinent in the world with varied climatic regions, topographic variation results in the very diverse ecological diversity. Litsea is a largest genus in the family Lauraceae differentiated by its dioecious nature, distributed in tropical and subtropical regions which is influenced by some environmental factors. Present research work focussed on distribution of genus in the central Western Ghats of Karnataka, India. Litsea species were collected from 2013 to 2018 in different sampling sites. A total of 12 species were identified and reported from this region. The diversity indices of Litsea vary from species to species as well as region to region. L. floribunda is frequently distributed in all the study sites and it showed highest density when compared with other species, whereas, L. deccanensis distributed only in Sakaleshpur region and it showed lower diversity. The highest number of Litsea species occurred in Sakaleshpur region (10 species) and Mullayyanagiri region having only one species that is L. floribunda. The results indicate that Litsea distribution and diversity is rich in moderate rainfall regions of Western Ghats. The macro and micro nutrients of the soil in the study area reflects the distribution of the genus. There is a gradual increasing in tendency of the species richness with increasing elevation when compared with lower elevated regions. The genus also showed more sensitive and positive association with the elevation factor.

Comparing the Features of Generation of CMEs Moving with Different Speed in the Field of View of the LASCO Coronagraphs

This study is aimed at finding an answer to the following question: are there any fundamental differences in the generation of coronal mass ejections (CMEs) with different speeds, especially low and high speeds, detected in the field of view of LASCO coronagraphs? Fast CMEs are conventionally understood as mass ejections with a linear projection velocity in LASCO field of view $${{V}_{{LIN}}}$$ > 1500 km/s; slow CMEs are those with $${{V}_{{LIN}}}$$ ≤ 600 km/s. CMEs with $${{V}_{{LIN}}}$$ between 600 and 1500 km/s are referred to as mass ejections with intermediate speed. The results of the analysis are presented by the example of three halo-type CME events (fast, slow, and intermediate) with sources in the sunspot groups removed from the center of the solar disk by no more than 45°. For analysis, we used data from SDO/AIA telescopes and the SDO/HMI instrument, as well as the LASCO C2 and C3 coronagraphs. The properties of active regions in which CMEs with different speeds have occurred are compared. The morphological features of the formation of the selected mass ejections based on the observations in the extreme ultraviolet lines are compared with features of their kinematics. Using the data of vector measurements of the photospheric magnetic field with the SDO/HMI instrument over the regions of CME formation, the altitude distributions of the magnetic field are calculated in the nonlinear force-free approximation. The analysis of these distributions showed that before the onset of a CME-related flare, the rate of altitude variation in the magnetic field above the CME generation site is noticeably different for all selected events.

Appraisal of Geomorphic Diversity with Special Reference to Basin-Area Extremity in Central Lesser Himalaya

ABSTRACT The standard for the selection of two fourth order watersheds for intensive geomorphic study was extremity in basin-area to assess diversity in between two watersheds in regard to their geomorphic environment. The diversity in geological traits reveals that the Phalal watershed was characterized by contact zone of two lithological formations (Augun gneiss 95% and Rautgara quartzites 5%) separated by north Almora thrust (NAT) while the entire Siya watershed was developed only in one formation, i.e. Rautgara (quartzites) Formation. The diversity in geo-morphometric personality and geomorphic evolution speaks of a differential development of both watersheds in context of stage of erosion. The zone of critical-height above which the erosion is acute is 1700 to 1800 m in Phalal watershed, whereas 1500 to 1600 m in Siya watershed; the hypsometric integral determines Phalal watershed (49.96 %) under middle-mature stage while Siya watershed (57.07 %) achieved early-mature stage. Diversity in erosion status was observed along the varying altitudes of the watersheds under different land use/cover. Diversity in the spatial distribution of altitude, erosion intensity, average slope versus land use/cover status under both watersheds determines the impact of basin-area extremity. The hazardous geomorphic processes also indicate the impact of basin-area extremity as eleven types of geomorphic hazards were experienced by the Phalal watershed while only four types of hazards were experienced by Siya watershed. Phalal watershed was 18.42 % hazardous area while 21.04 % hazardous area was possessed by Siya watershed. The hazard of ‘surficial erosion’ covers maximum area, i.e. 13.78 % in Phalal watershed while 20.52 % area is possessed by Siya watershed. Likewise maximum study units attained degree 4 instability for Phalal watershed (80%) while degree 2 instability for Siya (50%) watershed. Thus, basin–area has direct posture on geological traits, geomorphic evolution, geomorphometric personality and hazardous geomorphic processes while land use/cover status has no bearing on basin-area extremity under the studied watersheds.

Dynamical nature of tropospheric ozone over a tropical location in Peninsular India: Role of transport and water vapour

This paper deals with the temporal changes in the altitude distribution of tropospheric ozone (O3) based on the measurements by balloon-borne O3-sondes during 2011–2014, conducted at the tropical, coastal site Thiruvananthapuram on the south west coast of India. This is the first study from this region addressing the highly dynamic nature of tropospheric O3 profiles (in terms of their vertical structure and short-term changes) and attempting to categorise them based on 121 in-situ measured O3 profiles. The tropospheric O3 profiles could be categorised into four major groups namely (i) those with steady O3 mixing ratio (ii) with increasing mixing ratio, (iii) with mid-tropospheric enhancement and (iv) with multiple layers/laminar nature. The causative mechanisms of these different categories were examined. The observed differences in the tropospheric O3 distribution are attributed to meteorological conditions in particular the synoptic scale systems, long range transport, intrusion from stratosphere and photochemistry, most importantly, the effect of water vapour content. Water vapour and O3 showed complex dependence with positive and negative association depending on the precursor levels and availability of water vapour. The altitudinal changes in O3 also exhibited close association with those of potential temperature and equivalent potential temperature. An analysis of the seasonal characteristics of vertical distribution of tropospheric O3 also carried out along with the altitude-dependent seasonal behaviour. In general, the total column O3 estimated by the integration of O3-sonde retrieved profiles differed by about ±10% with those retrieved by satellite-based measurements. The TCO contributes to about 16% (34 DU) of the total column O3, with minimum of 9% in October and maximum of 27% on March. In general, the OMI retrievals under-estimates the O3-sonde derived TCO by 5–10 DU in all the seasons.

Tree seedling distribution, regeneration mechanism and response to climate change in alpine treeline ecotone

Tree seedlings are one of the important components in alpine treeline ecotone, whose regeneration is crucial to treeline migration in response to climate change. We analyzed the spatial distribution, regeneration of tree seedlings and their responses to climate change in treeline ecotone in recent decades. The spatial distribution of tree seedlings in treeline ecotone is dominated by diffuse and clustered forms, with different indicative significance for spatial dynamics of treeline. At global scale, the altitude distribution limits of tree seedlings are usually related to the length and average temperature of growing season, along with the species characteristics. However, precipita-tion plays an important role at regional scale. The initial stage of seedling recruitment is restricted by seed source, which determines seed distribution and germination to a great extent. Microenvironment facilitates seedling regeneration by providing shelter for establishment and improving their survival rate. The regeneration process is more relevant to multiple biotic, abiotic factors and their interactions. With global warming, rising temperature in treeline ecotone and more precipitation are more suitable for seedling regeneration of treeline species. The expansion of seedlings to higher elevations could be considered as the portent of timberline upwards migration. Due to species-specific adaption strategy, however, some trees only increase seedling density and timberline location is constant. In the future, it is necessary to take precise dating techniques, such as tree-ring and 14C dating, and conduct long-term in-situ monitoring and indoor simulation experiments. To provide scientific basis for mountain ecosystem restoration and conservation, we should strengthen the studies on spatial patterns and regeneration mechanism of seedlings in treeline ecotone at multiple spatio-temporal scales, the adaptation strategies of tree seedlings in different types of treeline ecotone and treeline dynamics prediction.

Terrain Morphometry and Mudflow Features in the Northern Slope of the Great Caucasus

Morphometric terrain parameters such as slope angles and altitudes make a considerable contribution to the features of mudflows. In order to assess the contribution of these factors, this study analyzes their characteristics in the Western, Central, and Eastern Caucasus on the basis of an original digital terrain model. The average slope angles in the Western Caucasus are higher by 0.5° than those in the Central and Eastern Caucasus, thus contributing to more active mudflow. On the other hand, the Western Caucasus is distinguished by lower altitude differences. From the standpoint of this factor, the Central Caucasus is the most mudflow hazardous. Hence, the absolute altitude distribution and high forestation neutralize the factor of more significant slope angles and ensure the less considerable mudflow danger in the Western Caucasus relative to the Central and Eastern Caucasus.

A Statistical Method for Determining Optical and Geometrical Characteristics of Cirrus Clouds

Altitude occurrences of cirrus clouds, their base, mid, and top heights are identified by using a powerful statistical approach called the Variance Centroid Method (VCM). This method is effective in determining the geometrical properties of cirrus clouds at a height range of 8 km to 20 km. This statistical method provides in-depth information on Generation Circulation Models (GCM’s) because of its significant role in the radiative balance of the earth’s atmosphere. The output related to geometrical and optical properties of cirrus clouds obtained from this statistical method for the years 2014 and 2015 are studied. Altitude distributions of base, mid, top, and thickness of tropical cirrus clouds are analyzed in terms of percentage occurrences. For the year 2014, it was found that 14.8%, 75.2%, and 9.9% of cirrus clouds were sub-visual, thin, and thick clouds and for the year 2015, 71.2% and 28.7% of cirrus clouds were found to be thin and thick clouds, and sub-visual types of clouds were not observed. The interdependence of optical depth with the depolarization ratio is discussed and it is observed that the correlation is negative (−0.0303) for the year 2014 and positive (0.1311) for the year 2015. High optical depths with values from 0.502 to 0.849 are observed in the height regions from 9 km to 15 km (for 2014) and for the year 2015, the observed value ranges from 0.514 to 0.822 for the height regions from 9 km to 11 km. Statistical variation of characteristics of tropical cirrus clouds is presented for the period of study. The characterization of these cirrus clouds is highly useful for climate modeling studies, and their impact plays a vital role in the Earth’s radiation budget at the top of the atmosphere.

Whole-genome analysis identifying candidate genes of altitude adaptive ecological thresholds in yak populations.

The domestic yak (Bos grunniens) is an iconic symbol of animal husbandry on the Qinghai-Tibet Plateau. Long-term domestication and natural selection have led to a wide distribution of yak, forming many ecological populations to adapt to the local ecological environment. High altitude is closely related to oxygen density, and it is an important environmental ecological factor for biological survival and livestock production. The aim of the present study was to perform a preliminary analysis to identify the candidate genes of altitude distribution adapted ecological thresholds in yak using next-generation sequence technology. A total of 15,762,829 SNPs were obtained from 29 yaks with high- and low-altitude distribution by genome-wide sequencing. According to the results of the selective sweep analysis with FST and ZHp, 21 candidate genes were identified. 14 genes (serine/threonine protein kinase TNNI3K, TEN1, DYM, ITPR1, ZC4H2, KNTC1, ADGRB3, CLYBL, TANGO6, ASCC3, KLHL3, PDE4D, DEPDC1B and AGBL4) were grouped into 32 Gene Ontology terms, and four genes (RPS6KA6, ITPR1, GNAO1 and PDE4D) annotated in 35 pathways, including seven environmental information processing and one environmental adaptation. Therefore, the novel candidate genes found in the current study do not only support new theories about high-altitude adaptation, but also further explain the molecular mechanisms of altitude adaptation threshold in yaks.

Modeling the Altitude Distribution of Meteor Head Echoes Observed with HPLA Radars: Implications for the Radar Detectability of Meteoroid Populations

Abstract The altitude distribution of meteors detected by a radar is sensitive to the instrument’s response function and can thus provide insight into the physical processes involved in radar measurements. This, in turn, can be used to determine the rate of ablation and ionization of the meteoroids and ultimately the input flux on Earth. In this work, we model the radar meteor head echo altitude distribution for three High Power and Large Aperture radar systems, by considering meteoroid populations from the main cometary family sources. In this simulation, we first use the results of a dynamical model of small meteoroids impacting Earth’s upper atmosphere to model the incoming mass, velocity, and entry angular distributions. We then combine these with the Chemical Ablation Model and establish the meteoroid ionization rates as a function of mass, velocity, and entry angle in order to determine the altitude at which these radars should detect the produced meteors and the portion of produced meteors from each population that are detected by these radars. We explore different sizes of head plasma as well as the possible effects on radar scattering of the head echo aspect sensitivity. We find that the modeled altitude distributions are generally in good agreement with measurements, particularly for ultra-high-frequency radars. In addition, our results indicate that the number of particles from Jupiter Family Comets (JFCs) required to fit the observations is lower than predicted by astronomical models. It is not clear yet if this discrepancy is due to the overprediction of JFC meteoroids by dynamical models or due to unaccounted physical processes in the treatment of ablation, ionization, and detections of meteoroids as they pass through Earth’s atmosphere.

Large-scale altitude distribution profile of auroral parallel electric potentials: A statistical analysis of Cluster data

It is generally believed that the heart of the Auroral Acceleration Region (AAR) is located between 5000 and 8000 km altitude above the auroral oval. Various altitude distribution profiles are suggested by different theories, including the transition layer model, which predicts that the strongest electric fields can be found at about 1 RE, and can vary depending on the plasma and geomagnetic conditions. However, there have been no specific experimental results that cover regions both below and well above such altitude. This paper presents a method for obtaining such a profile from AAR satellite crossings, applies it to a data set gathered from 116 Cluster spacecraft encounters with acceleration potential structures, and discusses the results. The crossings cover an altitude range between 0.63 RE and 2.9 RE. The outcome is the first empirical altitude distribution profile of the auroral acceleration potentials. The results suggest that the region within the altitude range of 0.9245 RE and 1.158 RE statistically contains 30% of the total potential, which is the largest fraction of the parallel potentials among all altitude segments of the same size. The altitude which equally divides the distribution of acceleration potentials was found at 1.076 RE (6863 km). The obtained parallel potential distribution is in agreement with both the magnetic mirror force theory and the transition layer model, and can hence provide a proper baseline for future missions to the AAR.

Organic carbon stocks in mountain grassland soils of northwestern Kashmir Himalaya: spatial distribution and effects of altitude, plant diversity and land use

Despite constituting important ecosystem of Kashmir Himalaya and being sensitive to climate change, data on soil organic carbon (SOC) in grasslands remain scarce. Present study was conducted in 20 grasslands that represent pasture and non-pasture types, with an aim to record SOC stocks at 5 sampling depths (0–10; 10–20; 20–30; 30–40 and 40–50cm), study its variation along altitude and elucidate how environmental factors affect this variation. SOC stocks exhibited high variability and ranged between 28.85 and 94.76 Mg C ha−1, with mean value of 54.52 Mg C ha−1, which was stored as 30.63, 22.98, 21.06, 14.89, and 10.41%, respectively at five depths. Differences in SOC stocks between pasture and non-pasture types were minor, with average stocks appearing slightly higher for pasture (59.69 ± 15.43 Mg C ha−1) than non-pasture (56.32 ± 17.01 Mg C ha−1). However non-pasture type had higher stocks particularly in upper soil layers. SOC exhibited negative relationship with soil depth and bulk density while increasing relationship with altitude, species richness and aboveground live and dead biomass was observed. On depth gradient, altitude affected subsurface (10–20cm) soils more distinctly than surface (0–10 cm) soils. Besides contributing baseline data, comparison of SOC provides possibility to determine management effects on SOC storage and consequently C sequestration.

Satellite-retrieved vertical profiles of methane over the Indian region: impact of synoptic­scale meteorology

ABSTRACT The altitude distribution of methane (CH4) is the least addressed topic in the greenhouse gas assessment over the Indian region. In the absence of the in-situ measurements, the satellite-based retrievals of the vertical distribution of CH4 using Atmospheric Infrared Sounder (AIRS) measurements during the period 2003–2015 were made use in this study for the first time to understand the 3D distribution (latitude-longitude-altitude) of CH4 over Indian region. Significant regional and seasonal variations are observed in the vertical distribution of CH4, even though it is a long-lived greenhouse gas and known to be well-mixed. Over most of the regions, the highest mixing ratio is observed during post-monsoon months and minimum in the pre-monsoon/monsoon season. The presence of a ‘high altitude peak’ in CH4 (around 1880 ppbv) around 300 hPa–250 hPa was noted in post-monsoon which is caused by the monsoon-associated convective updrafts and the anti-cyclonic system. The vertical profiles show seasonal variations which are region as well as altitude-dependent. Over the oceanic region, the highest seasonal amplitude of CH4 mixing ratio was observed over North–Arabian Sea due to the proximity of the source rich land regions. During the winter and pre-monsoon months, the latitudinal differences are absent throughout the troposphere. A consistent increasing trend in CH4, ranging from 1 ppbv year–1 to 6 ppbv year–1 is seen at all the tropospheric altitudes, with faster growth rates at higher altitudes, maximizing at 300 hPa–150 hPa. An approximate estimate of direct forcing due to CH4 lies in the range 0.80 W m–2–0.83 W m–2. The paper also presents a comparison of the in-situ measured upper tropospheric CH4 mixing ratio from CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) flight data and AIRS retrievals.

Empirical Phase Calibration for Multistatic Specular Meteor Radars Using a Beamforming Approach

AbstractSpecular meteor radars have proven useful for observing mesosphere and lower thermosphere altitudes. More recently, their capabilities have been enhanced by including multistatic configurations. In both cases, monostatic and multistatic, the multiantenna interferometer used to determine the location of the measurements needs to be carefully calibrated in phase. In this work we proposed a technique to calibrate the receiving phases of such interferometers, including the standard five‐antenna Jones configuration located on a plane and arbitrary configurations not necessarily located on a plane and not limited to five antennas. Our technique uses beamforming and nonlinear least squares fitting to determine the angle of arrivals that are consistent with the complex spatial coherences of the detected meteors. The optimization process uses a priori information based on the expected angular and altitude distribution of the echoes. The technique is demonstrated using real bistatic data. The obtained distribution of inverse decay time as a function of altitude is shown to be a sensitive and independent quality control feature of the applied calibration.

New insights into the range, morphology, and natural hybridization of wild Lactuca aculeata in Israel

In recent years we initiated extensive studies on the characterization of the population structure of wild Lactuca relatives (WLRs) originating from their center of origin and diversity in Southwest Asia. The objectives of our research program are related to the identification, collection, distribution, conservation and sustainable use of these unique plant genetic resources (PGR) for breeding. Natural populations of Lactuca aculeata Boiss., a wild lettuce, closely related and fully inter-fertile with cultivated lettuce, sativa L., were identified throughout northeastern Israel. The collection includes 485 seed samples, which is likely the largest and most diverse collection of this important WLR. Seeds were collected from 46 locations, representing its ecogeographic distribution in northeastern Israel. Together with 14 additional observed localities, we recorded our observations from a total of 60 native locations of L. aculeata. Thus, we assume that northeastern Israel is an ecological domain where natural L. aculeata populations can be found. The analyzed data allowed us to specify the borders of the growing area in the region, as well as to describe the ecological features of the habitats and altitude distribution of natural L. aculeata within the studied area. Notably, our data included new findings of native locations of L. aculeata on the western side of the watershed in Israel. Selected morphological characteristics, from the regeneration of 185 samples, verified the identity of all except one as L. aculeata. Some progenies (0.27%) of the original collected plants were identified as hybrids of L. aculeata x L. serriola.

Radar Reflectivity and Altitude Distributions of Lightning as a Function of IC, CG, and HY Flashes: Implications for LNOx Production

AbstractTwo dimensional (2‐D) histogram distributions of lightning flashes relative to radar reflectivity and altitude were created using a total of 41,180 intercloud/intracloud (IC) flashes, 3,326 cloud‐to‐ground (CG) flashes, and 4,349 hybrid (HY) flashes that originated in multicells; 111,479 IC flashes, 8,588 CG flashes, and 11,699 HY flashes that originated in mesoscale convective systems; and 91,283 IC flashes, 3,023 CG flashes, and 7,872 HY flashes that originated in supercells that occurred over northern Alabama and southern Tennessee. It was shown that although CG flashes initiate and propagate at the same altitude irrespective of storm type, IC flashes could have differences of up to 10 °C, while for HY flashes these differences increased to up to 20 °C relative to storm type. Further, IC, CG, and HY flashes propagated in lower reflectivities than where they initiated, while CG flashes initiated and propagated within higher reflectivities than IC and HY flashes. HY flashes were also twice as large as IC flashes and ~40% larger than CG flashes, and flashes that originated in mesoscale convective systems had larger overall sizes as compared to multicells and supercells. When comparing the new 2‐D histogram distributions to the legacy distributions used for the calculation of lightning‐produced nitrogen oxides (LNOx), it was shown that the new distributions perform much better, with higher Pearson product moment correlation coefficient values and much lower root‐mean‐square errors. These new distributions are thus more appropriate to use when modeling LNOx and will lead to more accurate LNOx estimations than using the legacy distributions.

Radar Reflectivity and Altitude Distributions of Lightning Flashes as a Function of Three Main Storm Types

AbstractIn an effort to improve our knowledge on the horizontal and vertical distribution of lightning initiation and propagation, ~500 multicells (producing a total of 72,619 flashes), 27 mesoscale convective systems (producing 214,417 flashes) and 23 supercells (producing 169,861 flashes) that occurred over northern Alabama and southern Tennessee were analyzed using data from the North Alabama Lightning Mapping Array and the Multi‐Radar Multi‐Sensor suite. From this analysis, two‐dimensional (2‐D) histograms of where flashes initiated and propagated relative to radar reflectivity and altitude were created for each storm type. The peak of the distributions occurred between 8.0 and 10.0 km (−24.0 to −38.5 °C) and between 30 and 35 dBZ for flashes that initiated within multicellular storms. For flashes that initiated within mesoscale convective systems, these peaks were 8.0–9.0 km (−27.1 to −34.6 °C) and 30–35 dBZ, respectively, and for supercells, they were 10.0–12.0 km (−42.6 to −58.1 °C) and 35–40 dBZ, respectively. The 2‐D histograms for the flash propagations were slightly different than for the flash initiations and showed that flashes propagated in lower reflectivities as compared to where they initiated. The 2‐D histograms were also compared to test cases; the root‐mean‐square errors and the Pearson product moment correlation coefficient (R) were calculated with several of the comparisons having R values >0.7 while the root‐mean‐square errors were always ≤0.017 (≤10%), irrespective of storm type. Finally, the mean flash sizes for the multicell, mesoscale convective system, and supercell flashes were 8.3, 9.9, and 7.4 km, respectively.

Conflict-risk assessment model for continuous climb operations

Continuous Climb Operations (CCO) enable aircraft to execute optimal departing trajectories. However, current airspace design may not allow the integration of CCO due to incompatibility with air traffic flow. This paper lays out a new conflict risk model and assesses the impact of CCO in complex airspace. In this document, conflict risk is defined as the combination of conflict probability between an aircraft pair (CCO and arrivals) and estimated air traffic flows. The authors set out a new approach to determining the probability of vertical conflicts. This approach is based on the altitude distributions at conflict points, which are estimated using simulations (CCO) and real data (arrivals). Using altitude distributions, it is possible to statistically determine the probability of two aircraft infringing the vertical separation minimum. This methodology is applied to Palma airport (Spain). Results show that it is feasible to integrate CCO except for one conflict point where air traffic flows need to be redesigned. Therefore, this new conflict risk model can form the basis of a future decision-making process to validate new flight procedures or modify existing ones.