Survey of the Universe
... They produce radiation across the electromagnetic spectrum at all wavelengths. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior [2]. During the study of radio signals originating from Sun, solar flares can be prominently recorded. ...
Solar bursts recorded in the frequency range 50 to 300 MHz by using log periodic dipole array over Kalyani (22°58´N, 88°46´E) have been statistically analyzed for the years 2011-2013. Scatter plots of flare intensity for both M-and X-class flares as well as the number of occurrences of the two categories have been examined. The characteristics of the auroral electrojet indices are correlated directly to the solar flare activity. The auroral indices data obtained from various sources are sorted accordingly. The daily averaged data of the auroral indices are plotted for a period of 5 years, 2009 to 2013. Regression analysis of the indices data has been done meticulously. The regression analysis data are also plotted as residual plots and line fit plots. We have tried to discuss the possible connection between the occurrences of solar flares and the auroral electrojet indices.
... The first change detection was to detect changes in the position by using 'blink' principle (Menzel, 1970). This approach was applied to detect differences between multi-temporal Landsat MSS images (Masry et al., 1975). ...
Four models are employed in the landscape change detection of the newly created wetland. The models include ones for patch connectivity, ecological diversity, human impact intensity and mean center of land cover. The landscape data of the newly created wetland in Yellow River Delta in 1984, 1991, and 1996 are produced from the unsupervised classification and the supervised classification on the basis of integrating Landsat TM images of the newly created wetland in the four seasons of the each year. The result from operating the models into the data shows that the newly created wetland landscape in Yellow River Delta had a great change. The driving focus of the change are mainly from natural evolution of the newly created wetland and rapid population growth, especially non-peasant population growth in Yellow River Delta because a considerable amount of oil and gas fields have been found in the Yellow River Delta. For preventing the newly created wetland from more destruction and conserving benign succession of the ecosystems in the newly created wetland, six measures are suggested on the basis of research results.
The major exercise in celestial navigation requires the calculation of the observer's latitude and longitude given a standard time, the data, some celestial data (almanac) and some celestial observations, usually the sextant heights of two celestial objects. Although this method successfully solves the problem, in practice it is more normal first of all to assume one's dead reckoning position, then for a given time precalculate the heights of two stars. Both of the major steps in these methods involve the use of the astronomical spherical triangle and many students stumble at this step and lose sight of the processes involved. The use of the stereographic projection allows the concepts to remain clear and the calculations and measurements to be completed rapidly, which more than compensates in the learning situation for the limitation in accuracy to +or-0.5.
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