Multi-wavelength observations of the 2014 June 11 M3.9 flare: temporal and spatial characteristics

We present multi-wavelength observations of an M-class flare(M3.9) that occurred on 2014 June 11. Our observations were conducted with the Dunn Solar Telescope(DST), employing adaptive optics, the multi-camera system Rapid Oscillations in Solar Atmosphere(ROSA), the new Hydrogen-Alpha Rapid Dynamics camera(HARDcam) in various wavelengths, such as Ca II K, Mg I b_2(at 5172.7 ?A), and Hα narrow band and G-band continuum filters. Images were re-constructed using the Kiepenheuer-Institut Speckle Interferometry Package(KISIP) code, to improve our image resolution. We observed intensity increases of ≈120%–150% in the Mg, Ca K and Hα narrow band filters during the flare. Intensity increases for the flare observed in the SDO EUV channels were several times larger, and the X-rays, as recorded by GOES, increased over a factor of 30 for the harder band. Only a modest delay was found between the onset of flare ribbons of a nearby sympathetic flare and the main flare ribbons observed in these narrow band filters. The peak flare emission occurred within a few seconds for the Ca K, Mg and Hα bands. Timedistance techniques indicate propagation velocities of ≈60 km s~(-1) for the main flare ribbon and as high as300 km s~(-1) for smaller regions, which we attribute to filament eruptions. This result and delays and velocities observed with SDO(≈100 km s~(-1)) for different coronal heights agree well with the simple model of energy propagation versus height, although a more detailed model for the flaring solar atmosphere is needed. Finally, we detected marginal quasi-periodic pulsations(QPPs) in the 40–60 s range for the Ca K,Mg and Hα bands, and such measurements are important for disentangling the detailed flare-physics.     

Effects of urbanization on river morphology of the Talar River,Mazandarn Province,Iran

In the present study, we investigate the effects of urbanization growth on river morphology in the downstream part of Talar River, east of Mazandaran Province, Iran. Morphological and morphometric parameters in 10 equal sub-reaches were defined along a 11.5 km reach of the Talar River after land cover maps were produced for 1955, 1968, 1994, 2005 and 2013. Land cover types changed extremely during the study period. Residential lands were found to have increased in area by about 1631%, while forest land and riparian vegetation decreased in by approximately 99.9 and 96.2%, respectively. The results of morphometric and morphological factors showed that average channel width (W) for all 11.5 km of the study river decreased by 84% during the study period, while the flow length increased by about 2.14%.