scholarly journals Comparison between IRI-2012 and GPS-TEC observations over the western Black Sea

2017 ◽  
Vol 35 (4) ◽  
pp. 817-824 ◽  
Author(s):  
Samed Inyurt ◽  
Omer Yildirim ◽  
Cetin Mekik
Keyword(s):  
Wave Propagation ◽  
Seasonal Variation ◽  
Standard Deviation ◽  
Density Profile ◽  
Electron Density Profile ◽  
Sunspot Activity ◽  
The Sun ◽  
The Earth ◽  
Maximum Value ◽  
Dynamic Layer

Abstract. The ionosphere is a dynamic layer which generally changes according to radiation emitted by the sun, the movement of the earth around the sun, and sunspot activity. Variations can generally be categorized as regular or irregular variations. Both types of variation have a huge effect on radio wave propagation. In this study, we have focused on the seasonal variation effect, which is one of the regular forms of variation in terms of the ionosphere. We examined the seasonal variation over the ZONG station in Turkey for the year 2014. Our analysis results and IRI-2012 present different ideas about ionospheric activity. According to our analysed results, the standard deviation reached a maximum value in April 2014. However, the maximum standard deviation obtained from IRI-2012 was seen in February 2014. Furthermore, it is clear that IRI-2012 underestimated the VTEC values when compared to our results for all the months analysed. The main source of difference between the two models is the IRI-2012 topside ionospheric representation. IRI-2012 VTEC has been produced as a result of the integration of an electron density profile within altitudinal limits of 60–2000 km. In other words, the main problem with regard to the IRI-2012 VTEC representation is not being situated in the plasmaspheric part of the ionosphere. Therefore we propose that the plasmaspheric part should be taken into account to calculate the correct TEC values in mid-latitude regions, and we note that IRI-2012 does not supply precise TEC values for use in ionospheric studies.

scholarly journals A probable cause of the Yearly variation of magnetic storms and auroræ.

1905 ◽  
Vol 74 (497-506) ◽  
pp. 90-95 ◽  
Author(s):  
Joseph Norman Lockyer ◽  
William J. S. Lockyer
Keyword(s):  
Seasonal Variation ◽  
Atmospheric Pressure ◽  
The Sun ◽  
Magnetic Disturbance ◽  
Yearly Variation ◽  
The Earth ◽  
Yearly Change ◽  
Meteorological Elements ◽  
Considerable Period ◽  
Magnetic Disturbances

The ordinary meteorological elements, such as atmospheric pressure, temperature, etc., have a yearly change satisfactorily explained as due to changes of the position of the earth’s axis in relation to the sun, or, in other words, the variation of the sun’s declination. There are, however, other phenomena, such as magnetic disturbances and auroræ, which have been explained differently. Thus, in regard to this seasonal variation Mr. Ellis has written, “The related physical circumstance is that at the equinoxes, when disturbance is more frequent, the whole surface of the earth comes under the influence of the sun, whilst at the solstices, when magnetic disturbance is less frequent, a portion of the surface remains for a considerable period in shadow.”

scholarly journals Arrival times of Flare/Halo CME associated shocks at the Earth: comparison of the predictions of three numerical models with these observations

2002 ◽  
Vol 20 (7) ◽  
pp. 917-935 ◽  
Author(s):  
S. M. P. McKenna-Lawlor ◽  
M. Dryer ◽  
Z. Smith ◽  
K. Kecskemety ◽  
C. D. Fry ◽  
...  
Keyword(s):  
Solar Wind ◽  
Standard Deviation ◽  
Energetic Particle ◽  
Numerical Models ◽  
Solar Wind Plasma ◽  
Shock Velocity ◽  
Shock Propagation ◽  
The Sun ◽  
Arrival Times ◽  
The Earth

Abstract. The arrival times at L1 of eleven travelling shocks associated both with X-ray flaring and with halo CMEs recorded aboard SOHO/LASCO have been considered. Close to the Sun the velocities of these events were estimated using either Type II radio records or CME speeds. Close to the Earth the shocks were detected in the data of various solar wind plasma, interplanetary magnetic field (IMF) and energetic particle experiments aboard SOHO, ACE, WIND, INTERBALL-1 and IMP-8. The real-time shock arrival predictions of three numerical models, namely the Shock Time of Arrival Model (STOA), the Interplanetary Shock Propagation Model (ISPM) and the Hakamada-Akasofu-Fry Solar Wind Model (HAFv.2) were tested against these observations. This is the first time that energetic protons (tens of keV to a few MeV) have been used to complement plasma and IMF data in validating shock propagation models. The models were all generally successful in predicting shock arrivals. STOA provided the smallest values of the "predicted minus measured" arrival times and displayed a typical predictive precision better than about 8 h. The ratio of the calculated standard deviation of the transit times to Earth to the standard deviation of the measurements was estimated for each model (treating interacting events as composite shocks) and these ratios turned out to be 0.60, 1.15 and 1.02 for STOA, ISPM and HAFv.2, respectively. If an event in the sample for which the shock velocity was not well known is omitted from consideration, these ratios become 0.36, 0.76 and 0.81, respectively. Larger statistical samples should now be tested. The ratio of the in situ shock velocity and the "Sun to L1" transit velocity (Vsh /Vtr) was in the range of 0.7–0.9 for individual, non-interacting, shock events. HAFv.2 uniquely provided information on those changes in the COBpoint (the moving Connection point on the shock along the IMF to the OBserver) which directly influenced energetic particle rise times. This model also illustrated the non-uniform upstream conditions through which the various shocks propagated; furthermore it simulated shock deformation on a scale of fractions of an AU. On the spatial scale (300 RE ), where near-Earth spacecraft are located, the passing shocks, in conformity with the models, were found to be locally planar. The shocks also showed tilting relative to the Sun-Earth line, probably reflecting the inherent directionality associated with their solar origin. Key words. Interplanetary physics (energetic particles; interplanetary shocks; solar wind plasma)

scholarly journals Differences Mastery Of Geography Concept Of Students Who Are Teached With Phet-Based Computer-Based Models And Students Are Teached Conventional On Basic Material Know The Earth (Experimental Study At Man I Kendari

2017 ◽  
Vol 1 (1) ◽  
pp. 80
Author(s):  
Muhammad Alam ◽  
La Ode Nursalam ◽  
La Ode Amaluddin
Keyword(s):  
Standard Deviation ◽  
Basic Material ◽  
Computer Assisted ◽  
Average Value ◽  
Minimum Value ◽  
The Earth ◽  
Maximum Value ◽  
Significant Difference ◽  
Post Test ◽  
Computer Based

This research aim to know differences mastery of geography concept of students who are teached with phet-based computer-based models and students are teached conventional on basic material know the earth at MAN I Kendari. The population of this study is All students class X MAN 1 Kendari enrolled in the 2015/2016 school year consisting of 3 classes with the number 86. The sample of this study is class X IPS2 and X IPS3 selected by using Barlet test that the results of all classes are homogeneous to the level Α = 0.05, indicated by the value of χ2 hit = 274.59 <χ2 = 5.99 Analysis of data in this study through descriptive and inferential analysis From the analysis of descriptive pre-test the experimental class obtained the maximum value of 53.3 and the minimum value of 13.3, the average value 32.82 and standard deviation of 10.27, while the control class pre-test obtained a maximum value of 50 and a minimum value of 6.6, the average value 29.11 and deviation standard 10.57. Post-test experimental class obtained maximum value 93.3, minimum value 30.6, average value 70.23 and standard deviation 15.19; While the control class post-test obtained a maximum value of 90, a minimum value of 25; Average value of 61.42 and standard deviation of 15.43. From inferential statistical results to test the hypothesis shows that hypothesis I, obtained the value -t (1-α / 2) / dk <thit <t (1-α) t (-0.975) (54) -1.331 <2.00, (interpolation) With α = 0.05 this shows no significant difference between the mean pre-test of the experimental class and the control class pre-test. In the second hypothesis, the value of t (0.975) (54) 1.673 (2.153> 1.673) indicates that the average post-test grade of the experimental class is better than the average post-test value of the control class. Hypothesis III, obtained the value of thit> t (0.975) (54) 1.673 (1.673 <1.792) which means that there is a significant difference between the gain value of the experimental class and the control class gain. This means that computer-assisted learning is more effective than conventional learning in an effort to improve the mastery of student learning concepts of class X on the subject of knowing the earth with 95% confidence level (α = 0.05).

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Estimation of the electron density profile in the D region from rocket measurement of VLF signals from a ground based transmitter

1981 ◽  
Vol 64 (11) ◽  
pp. 68-74
Author(s):  
Isamu Nagano ◽  
Masayoshi Mambo ◽  
Tetsuo Fukami ◽  
Koji Namba ◽  
Iwane Kimura
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Rocket Measurement ◽  
D Region

Spots on the Sun and Life on the Earth

2019 ◽  
Vol 15 (1) ◽  
pp. 73-77
Author(s):  
Valentina V. Ukraintseva ◽  
Keyword(s):  
The Sun ◽  
The Earth

COMPARISON OF LEARNING MATH LEARNING RESULT STUDENTS WITH SAVI MODEL AND NHT MODEL ON STUDENT SMKN 1 KOLAKA

2018 ◽  
Vol 3 (1) ◽  
pp. 22-27
Author(s):  
S. Supratman ◽  
Sri Wulandari Muhlis
Keyword(s):  
Standard Deviation ◽  
Student Learning ◽  
Learning Outcomes ◽  
Mathematics Learning ◽  
Learning Model ◽  
T Test ◽  
Mathematics Students ◽  
Learning Models ◽  
Maximum Value ◽  
Learning Mathematics

The formulation of the problem in this research are: (1) How the result of learning mathematics of students after taught by SAVI learning model?, (2) How the result of learning mathematics of students after taught by NHT learning model?, (3) Is the result of learning mathematics of students who taught with SAVI learning model is higher than students taught by NHT learning model. The purpose of this study are: (1) To know how the results of learning mathematics students after teaching with SAVI learning model, (2) To find out how the results of learning mathematics students after being taught with NHT learning model, (3) To determine whether the results of learning mathematics students taught by SAVI learning models higher than students taught by NHT learning models. Type of research using experimental method. The population in this study is all students of class X spread in 11 parallel classes with the number of 310 people. Sampling was done by using cluster random sampling technique. In this research as a sample taken 2 classes from the entire population that is class X A3 as experiment class 1 using SAVI learning model and class X A1 as experiment class 2 using NHT learning model. From result of data analysis obtained that: (1) result of student learning taught by using SAVI learning model which consist of 25 students show minimum value 62, maximum value 96, mean (mean) 80,36, with standard deviation 9,10; (2) student learning outcomes taught using NHT learning model consisting of 25 students showing minimum score 62, maximum value 96, mean (mean) 79,62, with standard deviation 10,512; (3) result of t-test analysis using independent sample t-test obtained tcount = 0,302 at = 0,05 with degrees of freedom (dk) = 48 obtained t table = 2,011. Because t <t table then Ha is rejected and H0 is accepted. So it can be concluded that the mathematics learning outcomes of students who were taught with the SAVI model was not higher than the students taught by the NHT model.

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