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VLF/LF Amplitude Perturbations before Tuscany Earthquakes, 2013

Natural Science 2017年第12期9卷 437-456页

作者： Balaram Khadka Keshav Prasad Kandel Sudikshya Pant karan bhatta Basu Dev Ghimire St. Xavier’s College Kathmandu Nepal Nepalese Center for Research in Physical Sciences (NCRPS) Kathmandu Nepal

The US Navy VLF/LF Transmitter’s NSY signal (45.9 kHz) transmitted from Niscemi, Sicily, Italy, and received at the Kiel Long Wave Monitor, Germany, was analyzed for the period of two months, May and June (EQ-month) of 2013. There were 12 earthquakes of magnitude greater than 4 that hit Italy in these two months,?of which the earthquake of 21st June having magnitude of 5.2?and a shallow focal depth of 5 km was the major one. We studied the earthquake of 21st of June 2013, which struck Tuscany,?Central Italy, (44.1713°N and?10.2082°E) at 10:33 UT, and also analyzed the effects of this earthquake on the?sub-ionos-?pheric VLF/LF signals. In addition, we also studied another earthquake, of magnitude 4.9, which hit the same place at 14:40 UT on 30th of June and had shallow focal depth of 10 km. We assessed the data using terminator time (TT) method and night time fluctuation method and found unusual changes in VLF/LF amplitudes/phases. Analysis of trend, night time dispersion, and night time fluctuation was also carried and several anomalies were detected. Most ionospheric perturbations in these parameters were found in the month?of June, from few days to few weeks prior to the earthquakes. Moreover, we filtered the possible effects due to geomagnetic storms, auroras, and solar activities?using parameters like?Dst index, AE index, and Kp index for analyzing the geomagnetic effects,?and Bz (sigma) index, sunspot numbers, and solar index F10.7 for analyzing the solar activities for the confirmation of anomalies as precursors.

关键词： D-Layer VLF/LF Terminator Times SST SRT DLPT DLDT Night Time Fluctuation

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A Study on the VLF/LF Long Term Amplitude Oscillations Associated with Frequencies 37.5 kHz and 45.9 kHz Received at Keil Longwave Monitor, Keil, Germany

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International Journal of Geosciences 2017年第9期8卷 1080-1090页

作者： Govinda Sharma Keshav Prasad Kandel Balaram Khadka Peter Wilhelm Schnoor karan bhatta Basu Dev Ghimire Aditya Singh Thapa St. Xavier’s College Kathmandu Nepal Nepalese Center for Research in Physical Sciences (NCRPS) Kathmandu Nepal Department of Physics St. Xavier’s College Kathmandu Nepal Keil Longwave Monitor Keil Germany

The middle and upper atmosphere of Earth displays many large-scale oscillations in several parameters. Of these oscillations, Atmospheric Oscillation (AO) and Semi-annual Oscillation (SAO) are prominent ones. In this work, we have analyzed the Very Low Frequency/Low Frequency (VLF/LF) data from two of the transmitters of frequency 45.9 kHz at NSY, Sicily, Italy and 37.5 kHz at Grindavik, Iceland. The selected Trasmitter-Receiver Great Circle Path (TRGCP) is middle latitude which is marine in case of Grindavik TRGCP and terrestrial in case of NSY TRGCP. The VLF/LF signals are bounced back and forth from D-layer of ionosphere (altitude at ~65 km during day and ~95 km during night) in Earth-ionospheric waveguide. This infers the presence of atmospheric oscillations as a consequence of change in ionization and recombination rates. Many works related to AO and SAO are mostly done only for equatorial region of the ionosphere and authors have reported the elegant dominancy of AO and SAO in the VLF/LF amplitude pattern over years. To our surprise, in our work it is seen that not only AO and SAO but also other oscillations are necessary to model the oscillation pattern of middle latitude ionosphere.

关键词： VLF/LF D-Layer SAO AO TRGCP NSY Grindavik

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Distribution and Habitat Preference of Red Panda (<i>Ailurus fulgens fulgens</i>) in Jumla District, Nepal

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Open Journal of Ecology 2014年第15期4卷 989-1001页

作者： Manoj bhatta karan Bahadur Shah Bhupendra Devkota Rajiv Paudel Saroj Panthi Amrit Science Campus Kathmandu Nepal Natural History Museum Tribhuvan University Kathmandu Nepal College of Applied Science Kathmandu Nepal Winrock International Lalitpur Nepal Department of Forests District Forest Office Darchula Nepal

Reliable and sufficient information regarding status, distribution and habitat preference of red panda (Ailurus fulgens fulgens) is lacking in Nepal. The research activities on red panda in the mid-western Nepal are very limited, so the status of red panda in the region is quite unknown. The study conducted during May, 2013 in three Village Development Committees (VDCs) namely Godhemahadev, Malikathata and Tamti of Jumla district was an important step for providing vital information including distribution and habitat preference of this species. The study included the reconnaissance, key informants survey, interviews and consultation for the most potential area identification, opportunistic survey comprising the direct observation and indirect sign count method for the presence and distribution, habitat assessment consisting vegetation sampling and ocular estimation. The study revealed the presence of red panda in three forests namely Bahirepatan, Imilchadamar and Tyakot of Godhemahadev, Tamti and Malikathata VDCs respectively. The species was found distributed between 2880 and 3244 m with an average dropping encounter rate of 1.04 per hour of searching effort and 12 pellets per dropping. Red panda mostly preferred the habitat in the elevation range of 2900 - 3000 m with southwest facing steep slopes (36? - 45?), associated with water sources at the distance of ≤100 m. Trees such as Acer spp., Betula utilis and Quercus semecarpifolia, shrub species of Elaeagnus parvifolia, Drepanostachyum spp. and Jasminum humile, and the herbs like Polygonatum cirrhifolium, Fragaria nubicola and Galium asperifolium were found to be the most preferred species by red panda. The red panda preferred the habitat with dense crown coverage (>20% - 100%) and 31% - 50% ground cover. Fallen logs (39%) were the most preferred substrate used for defecation.

关键词： Distribution Habitat Preference Jumla Red Panda Sign

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