scholarly journals Ionospheric GPS-TEC responses from equatorial region to the EIA crest in the South American sector under intense space weather conditions

Author(s):  
A.J. de Abreu ◽  
E. Correia ◽  
C.M. Denardini ◽  
R. de Jesus ◽  
K. Venkatesh ◽  
...  
2007 ◽  
Vol 25 (2) ◽  
pp. 399-406 ◽  
Author(s):  
A. F. Medeiros ◽  
H. Takahashi ◽  
R. A. Buriti ◽  
J. Fechine ◽  
C. M. Wrasse ◽  
...  

Abstract. An all-sky CCD imager for OH, O2 and OI (557.7 nm) airglow emission measurements was operated at São João do Cariri (Cariri), Brazil (7° S, 36° W), from October 2000 to December 2004. A large amount of image data, more than 3000 h of observation and around 1000 wave events, makes it possible to classify the gravity wave characteristics, which are statistically significant. The observed waves show a typically short horizontal wavelength (5–45 km) and a short period (5–35 min), and horizontal phase speeds of 1 to 80 m/s. In most cases band-type waves (horizontal wavelength between 10 and 60 km) showed a clear preference for the horizontal propagation direction from the South American continent to the Atlantic Ocean. Ripples also have similar features but with different anisotropy. In this paper we focus our discussion on the wave characteristics of the bands and ripples and a comparison between them.


2015 ◽  
Vol 33 (1) ◽  
pp. 79 ◽  
Author(s):  
Clezio Marcos Denardini ◽  
Marlos Rockenbach Da Silva ◽  
Mauricio Alfredo Gende ◽  
Sony Su Chen ◽  
Paulo Roberto Fagundes ◽  
...  

ABSTRACT. In this paper we present the first steps given towards the development of the South American K index (Ksa) based on the measurements made by the Embrace Magnetometer Network. We present: (a) a description of the magnetometer and of the network; (b) the procedure used to calibrate the network equipments; (c) the procedure to obtain each station K scale and its corresponding upper limits of ranges for the three-hour-range station K index (thereafter referred as K9 threshold); and (d) some particularities regarding the Quiet Day Curve (QDC) deviation and its long term variation.Keywords: space weather, magnetic index, magnetometer network, aeronomy.RESUMO. No presente artigo, apresentamos os primeiros passos realizados para desenvolvermos o índice K sul-americano (Ksa) baseado nas medidas feitas pela rede Embrace de magnetômetros. Apresentamos (a) uma descrição do equipamento utilizado, bem como da rede de magnetômetros; (b) o procedimento adotado para calibrar todos os equipamentos individuais da rede; (c) o procedimento para se obter a escala K de cada estação magnética e o seu correspondente limite superior para o índice K de três horas (doravante denominado limiar K9); e (d) algumas particularidades com respeito à obtenção da curva do Dia Quieto (QDC) e suas variações de longos períodos.Palavras-chave: clima espacial, índice magn´etico, rede de magnetômetros, aeronomia.


2020 ◽  
Vol 105 (2) ◽  
pp. 183-194
Author(s):  
Fernando O. Zuloaga ◽  
Sandra S. Aliscioni ◽  
M. Amalia Scataglini

Generic boundaries of the South American species Panicum longipedicellatum Swallen are explored and compared with allied genera of the tribe Paniceae. On the basis of morphological, anatomical, and molecular characters a new genus, Cnidochloa Zuloaga, is proposed. The phylogenetic position of the new genus within the Paniceae is evaluated.


Peanuts are plants of the tropical zone, therefore, for its growth and development, high temperature indicators are needed during a fairly long growing season. The climatic parameters of the south of Ukraine correspond to the needs of this culture, and today there is positive experience in growing peanuts in this region. In order to increase the efficiency of growing peanuts in the conditions of the Steppe zone, it is necessary to carry out genetic selection work to study and select a more adapted source material in order to create highly productive Ukrainian varieties adapted to the arid zone conditions. At the initial stage of this work, it is necessary to have clear signs and characteristics for evaluating the studied genotypes, and the existing methods for describing the characters and conducting an examination for distinctness, uniformity, and stability are incomplete and do not meet the requirements for in-depth work on private genetics and culture breeding. For our work, we used 18 peanut genotypes as a material, which make up the collection of the Institute of Oilseeds of NAASU. Studies were carried out in 2018 and 2019, in different weather conditions. All measurements, observations and statistical processing in the study of samples were carried out in accordance with generally accepted methods. When conducting a comparative analysis of the two methods for describing the signs of underground peanuts, it was found that one of the methods contains 23 signs and the other 17. The signs of the vegetative part of plants that characterize the habit and structure of the leaf predominate in both methods. We have identified and proposed for description 9 new characters in peanut plants: 2 - leaf characters (additional leaves and pubescence); 1 - the structure of beans (weight 100 beans); 1 - an economically valuable trait (the presence of nodules on the roots); 5 - flower features (size and color of the flower and border). In terms of plant habitat, Ukrainian Stepnyak and Krasnodar 13 varieties were distinguished, which had the highest height (43.8 cm) and the largest number of branches (9.3 pcs.). In addition to morphological identification features for the description and examination of distinctness, uniformity and stability, we have also studied the quantitative characteristics of underground peanuts. It was established that the height of peanut plants in the field conditions of the south of Ukraine ranged from 14 to 44 cm. The highest variety was the Ukrainian Stepnyak variety, and the shortest one was Pink large. The largest number of branches is 9.3 pcs. noted in the variety Krasnodar 13, and the smallest 4.62 pcs. - at L3. And the largest flower of 1.91 cm stood out White-pink 3. The quantitative traits we studied are characterized by continuous variability, which is due to the interaction between genes and the environment. Thus, to identify varietal variability in underground peanuts, it is necessary to use both existing methods, and in the near future, work should be done to combine them with the inclusion of new identified characters to more clearly identify the genotypes of this new valuable oilseed crop.


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