Coronal Mass Ejection of 15 May 2001: I. Evolution of Morphological Features of the Eruption     

D.?Mari?i?Email author  B.?Vr?nak  A.?L.?Stanger  A.?Veronig 《Solar physics》2004,225(2):337-353

We study the initiation and development of the limb coronal mass ejection (CME) of 15 May 2001, utilizing observations from Mauna Loa Solar Observatory (MLSO), the Solar and Heliospheric Observatory (SOHO), and Yohkoh. The pre-eruption images in various spectral channels show a quiescent prominence imbedded in the coronal void, being overlaid by the coronal arch. After the onset of rapid acceleration, this three-element structure preserved its integrity and appeared in the MLSO MK-IV coronagraph field of view as the three-part CME structure (the frontal rim, the cavity, and the prominence) and continued its motion through the field of view of the SOHO/LASCO coronagraphs up to 30 solar radii. Such observational coverage allows us to measure the relative kinematics of the three-part structure from the very beginning up to the late phases of the eruption. The leading edge and the prominence accelerated simultaneously: the rapid acceleration of the frontal rim and the prominence started at approximately the same time, the prominence perhaps being slightly delayed (4 – 6 min). The leading edge achieved the maximum acceleration a_max 600 ± 150 m s^–2 at a heliocentric distance 2.4 –2.5 solar radii, whereas the prominence reached a_max 380± 50 m s^–2, almost simultaneously with the leading edge. Such a distinct synchronization of different parts of the CME provides clear evidence that the entire magnetic arcade, including the prominence, erupts as an entity, showing a kind of self-similar expansion. The CME attained a maximum velocity of v_max 1200 km s^–1 at approximately the same time as the peak of the associated soft X-ray flare. Beyond about 10 solar radii, the leading edge of the CME started to decelerate at a–20 m s^–2, most likely due to the aerodynamic drag. The deceleration of the prominence was delayed for 10 –30 min, which is attributed to its larger inertia.  相似文献   

Occupational hazards in printing industry   总被引：1，自引：1，他引：0  

J. S. Kiurski  B. B. Marić  S. M. Aksentijević  I. B. Oros  V. S. Kecić 《International Journal of Environmental Science and Technology》2016,13(3):955-972

This paper, through certain printing techniques, examines the types of occupational pollutants and the adverse impacts of the printing process. Also, it proposes the measures for better preservation and environmental protection. The paper analyzes the results of the quantitative identification of hazardous materials from various printing techniques: pad, screen, offset, flexographic, and digital. The study included the analysis of waste printing inks and purification of printing wastewater with adsorption methods. Besides that, the preliminary monitoring of ambient indoor air quality was performed. The multiple regression analysis was applied on the obtained experimental results, in order to determine the mutual correlation between the ozone and the total volatile organic compounds and microclimate parameters. It was observed that a quantitative correlation exists between the investigated occupational hazards, which also indicate the strength of the agreement. The obtained results could be useful to evaluate the tendency of hazardous air pollutants in printing industries worldwide.  相似文献   

Eco-labeling of seafood: Does it affect the harvesting patterns of Norwegian fishermen?     

Kine Mari Karlsen  Øystein HermansenBent M. Dreyer 《Marine Policy》2012

The aim of this paper is to compare the criteria for eco-labeling of wild-caught fish in the Norwegian eco-certified fisheries, and to study if these eco-labels affect the harvesting patterns of Norwegian fishermen. The eco-labels Marine Stewardship Council (MSC), KRAV and Friend of the Sea (FOS) as applied in 2009 were studied. In this study, the harvesting patterns are defined by using the following parameters: season, catch area, size of fishing vessel, gear type, bycatch, location of landing site and distance to the fishing ground. KRAV had more specific criteria than did MSC and FOS in specific fisheries regarding time of the fishing effort, catch area, size of fishing vessels, gear type (e.g. hook size, and the use of beam trawlers was not permitted) and distance to the fishing ground. The findings show that few of the eco-label requirements influenced these aspects in Norwegian fisheries.  相似文献   

Influence of microclimate and geomorphological factors on alpine vegetation in the Western Swiss Alps     

Elisa Giaccone  Miska Luoto  Pascal Vittoz  Antoine Guisan  Grégoire Mariéthoz  Christophe Lambiel 《地球表面变化过程与地形》2019,44(15):3093-3107

Among the numerous environmental factors affecting plant communities in alpine ecosystems, the influence of geomorphic processes and landforms has been minimally investigated. Subjected to persistent climate warming, it is vital to understand how these factors affect vegetation properties. Here, we studied 72 vegetation plots across three sites located in the Western Swiss Alps, characterized by high geomorphological variability and plant diversity. For each plot, vascular plant species were inventoried and ground surface temperature, soil moisture, topographic variables, earth surface processes (ESPs) and landform morphodynamics were assessed. The relationships between plant communities and environmental variables were analysed using non-metric multi-dimensional scaling (NMDS) and multivariate regression techniques (generalized linear model, GLM, and generalized additive model, GAM). Landform morphodynamics, growing degree days (sum of degree days above 5°C) and mean ground surface temperature were the most important explanatory variables of plant community composition. Furthermore, the regression models for species cover and species richness were significantly improved by adding a morphodynamics variable. This study provides complementary support that landform morphodynamics is a key factor, combined with growing degree days, to explain alpine plant distribution and community composition. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.  相似文献   

Origin of the early Cenozoic belt boundary thrust and Izanagi–Pacific ridge subduction in the western Pacific margin     

Gaku Kimura  Yujin Kitamura  Asuka Yamaguchi  Jun Kameda  Yoshitaka Hashimoto  Mari Hamahashi 《Island Arc》2019,28(5)

The belt boundary thrust within the Cretaceous–Neogene accretionary complex of the Shimanto Belt, southwestern Japan, extends for more than ~ 1 000 km along the Japanese islands. A common understanding of the origin of the thrust is that it is an out of sequence thrust as a result of continuous accretion since the late Cretaceous and there is a kinematic reason for its maintaining a critically tapered wedge. The timing of the accretion gap and thrusting, however, coincides with the collision of the Paleocene–early Eocene Izanagi–Pacific spreading ridges with the trench along the western Pacific margin, which has been recently re‐hypothesized as younger than the previous assumption with respect to the Kula‐Pacific ridge subduction during the late Cretaceous. The ridge subduction hypothesis provides a consistent explanation for the cessation of magmatic activity along the continental margin and the presence of an unconformity in the forearc basin. This is not only the case in southwestern Japan, but also along the more northern Asian margin in Hokkaido, Sakhalin, and Sikhote‐Alin. This Paleocene–early Eocene ridge subduction hypothesis is also consistent with recently acquired tomographic images beneath the Asian continent. The timing of the Izanagi–Pacific ridge subduction along the western Pacific margin allows for a revision of the classic hypothesis of a great reorganization of the Pacific Plate motion between ~ 47 Ma and 42 Ma, illustrated by the bend in the Hawaii–Emperor chain, because of the change in subduction torque balance and the Oligocene–Miocene back arc spreading after the ridge subduction in the western Pacific margin.  相似文献   

2-Gyr Simulation of the Oort-cloud Formation II. A Close View of the Inner Oort cloud after the First Two Giga-years     

Giuseppe Leto  Marián Jakubík  Tomáš Paulech  Luboš Neslušan  Piotr A. Dybczyński 《Earth, Moon, and Planets》2009,105(2-4):263-266

We simulate the formation of the Oort cloud (OC) till the age of 2 Gyr starting from an initial disc of planetesimals made by 10 038 test particles. The results on the outer part of the distant comet reservoir are reported by Neslu?an et al. (this issue). Here we deal with the evolution of the population and structure at 2 Gyr of the complementary inner part of the Oort cloud. The dynamical evolution of the massless test particles was followed via the numerical integration of their orbits. We considered the perturbations produced by four giant planets assuming they have their current orbits and masses, as well as the perturbations caused by the Galactic tide and passing stars. The efficiency of the formation of inner OC is found to be very low: only about 1.1% of all considered particles ended in this part of the OC. At 2 Gyr, the dynamics of the inner cloud is mainly governed by the dominant z-term of the Galactic tide. The number density of the bodies is proportional to the heliocentric distance, r, as r ^?3.53. The directional distribution of orbits is still strongly inhomogeneous. There are large empty regions in the space angles around the Galactic Equator points with the galactic longitude 90 and 270° (non-rotating frame), or there are only few bodies having the ecliptical latitude higher than +60° or lower than 60°. A strong concentration of objects at the Ecliptic is apparent up to ≈1,000 AU, with a possible—but still not proved—extension to ≈1,500 AU. Beyond r ≈ 6,000 AU, bodies directly above and below the Sun, with respect to the Ecliptic, are absent.  相似文献   

Relative Kinematics of the Leading Edge and the Prominence in Coronal Mass Ejections     

Darije Maričić  Bojan Vršnak  Dragan Roša 《Solar physics》2009,260(1):177-189

We present a statistical analysis of the relationship between the kinematics of the leading edge and the eruptive prominence in coronal mass ejections (CMEs). We study the acceleration phase of 18 CMEs in which kinematics was measured from the pre-eruption stage up to the post-acceleration phase. In all CMEs, the three part structure (the leading edge, the cavity, and the prominence) was clearly recognizable from early stages of the eruption. The data show a distinct correlation between the duration of the leading edge (LE) acceleration and eruptive prominence (EP) acceleration. In the majority of events (78%) the acceleration phase onset of the LE is very closely synchronized (within ± 20 min) with the acceleration of EP. However, in two events the LE acceleration started significantly earlier than the EP acceleration (> 50 min), and in two events the EP acceleration started earlier than the LE acceleration (> 40 min). The average peak acceleration of LEs (281 m s⁻²) is about two times larger than the average peak acceleration of EPs (136 m s⁻²). For the first time, our results quantitatively demonstrate the level of synchronization of the acceleration phase of LE and EP in a rather large sample of events, i.e., we quantify how often the eruption develops in a “self-similar” manner.  相似文献   

Evaluation of inundation areas resulting from the diversion of an extreme discharge towards the sea: case study in Tabasco,Mexico     

Adrián Pedrozo‐Acuña  I Mariño‐Tapia  C Enriquez  Gabriela Medellín Mayoral  Fernando J. González Villareal 《水文研究》2012,26(5):687-704

This investigation comprises the hydraulic characterisation of a river located in the Mexican State of Tabasco, including the performance of its flood plain under the action of an extreme river discharge. This is done through the combination of a high‐quality validation dataset, remote sensing information, and a standard 2D numerical model. The dataset was collected during an intensive field campaign that took place in August 2009. In particular, in situ measurements of river discharge, bathymetry, water level, and velocities through a whole tidal cycle are employed along with multi‐spectral satellite imagery. The purpose of this study is twofold. Firstly, the integrated approach comprising the combination of a 2D hydrodynamic model, high‐quality in situ measurements and satellite imagery reduce the uncertainty in the model parameterisation and results. Secondly, it is shown that freely available sources of information, such as the Shuttle Radar Topographic Mission (SRTM) data can be processed and utilized in 2D hydraulic models. This is particularly important in countries where high‐resolution elevation data is not yet available. It is demonstrated that the selected approach is useful when the study of possible consequences in a flood plain induced by an extreme flood discharge are sought. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Arctic Mackenzie Delta channel planform evolution during 1983–2013 utilising Landsat data and hydrological time series          下载免费PDF全文

Jenni‐Mari Vesakoski  Tua Nylén  Berit Arheimer  David Gustafsson  Kristina Isberg  Markus Holopainen  Juha Hyyppä  Petteri Alho 《水文研究》2017,31(22):3979-3995

Arctic deltas, such as the Mackenzie Delta, are expected to face major climate change and increased human influence in the near future. Deltas are characterised by highly dynamic fluvial processes, and changing climate will cause considerable evolution of the riverine environment. The changes are difficult to predict with existing knowledge and data. This study quantified channel planform change of the Mackenzie Delta (1983–2013), analysing its temporal and spatial patterns. We addressed the main obstacle of research on large remote areas, the lack of data, by developing a unique work flow that utilised Landsat satellite imagery, hydrological time series, remote sensing‐based change analysis, and automatic vectorisation of channels. Our results indicate that the Mackenzie Delta experienced constant evolution but at a highly varying rate over the 30 years. The study demonstrates that the magnitude and duration of flood peaks and the presence of spring ice breakup floods determine the rate of Arctic delta planform change. Changing winter conditions and spring flood magnitudes may therefore affect the stability of Arctic deltas. However, no clear trends towards decreased recurrence or magnitude of spring floods or increased instability of the delta plain have yet been observed in the Mackenzie Delta. The delta plain was most dynamic at the beginning and at the end of the examined period, corresponding to intense flooding, whereas the rates of change were subtle during the low‐flood period 1994–2007. The largest changes have occurred along the wide Middle Channel and in the outermost delta. Relative to their size, however, smaller meandering channels have been highly dynamic. Hotspots of change in the delta plain are located in anastomosing and braiding channel segments and, at the local scale, in point bars and cut‐banks along meandering channels. Our study describes how Landsat satellite data can be utilised for advancing fluvial geomorphological research in remote areas. However, cloudiness in the delta restricts production of dense time series with simultaneous coverage of the whole area and requires manual preprocessing.  相似文献   

Air pollution caused by manufacturing coal from petroleum coke in Argentina     

Juan C. Bidegain  Marcos A. E. Chaparro  Débora C. Marié  Sandra Jurado 《Environmental Earth Sciences》2011,62(4):847-855

Environmental pollution and its harmful consequences for the population’s health derived from coal production in the locality of Ensenada (Argentina) is studied by magnetic and non-magnetic means. Coke is used for the production of industrial coal. This is a final product obtained in petroleum refineries. Coke is a non-magnetic material showing values of magnetic susceptibility close to zero. Conversely, the magnetic susceptibility of the coal released from factory chimneys is considerably enhanced due to the building of magnetic fibers and spherules inside the furnace, used for coal production. Due to this property, the magnetic content of coal can be used as environmental proxy for studying the environmental impact caused by coal industries in urban areas. The values of magnetic susceptibility decrease as the distance from the contamination source increases. This indicates that magnetic concentration is lower. The grain size of magnetic particles also decreases according to the distance, which is seen when analyzing the grain size parameters. According to the different non-magnetic approaches applied, the particles released by the industry, which affect the region, fall within the rank of breathable particles (<2.5 μm). Besides, inhalable particles are also found (2.5–10 μm). Such determinations are consistent with inter-parametric ratios applied in the study of grain sizes. The undesirable dust of the local coal industry also carries heavy metals which are dangerous for the population’s health, like Zn, Cu, Pb and V.  相似文献