Gravity, GPS and geomagnetic data in India

Gravity, Global Positioning System (GPS) and Geomagnetic data sets in India are acquired by different research, academic and government institutions, under various projects. These data sets have extensively been utilized for natural resources and lithopsheric explorations, earthquake studies, atmospheric and ionospheric studies, control surveys, aircraft navigation, etc. The data are archived at individual institutions and have different modes of procurement considering some of the data, e.g., gravity data are classified in nature. Some of these data sets are contributed to the international observational network for example IGS and INTERMAGNET and are available as open source for the scientific communities. Present article provides information about different types of available Gravity, GPS and Geomagnetic data, their archival and mode of availability to the user community

Very low latitude (L = 1.08) whistlers and correlation with lightning activity

We present analysis of more than 2000 lightning-generated whistlers recorded at a low-latitude station, located at Allahabad (geographic latitude, 25.40N; geographic longitude, 81.93E; L = 1.081), India, during December 2010 to November 2011. The main focus of this work is on the correlation between observed low-latitude whistlers and lightning activity detected by the World-Wide Lightning Location Network near the conjugate point (geography 9.87S, 83.59E) of Allahabad. Whistler occurrence is higher in the postmidnight period as compared to the premidnight period. Whistlers were observed in the daytime only on 2 days that too before 8:30 LT (morning). Seasonally, occurrence is maximum during winter months, which is due to more lightning activity in the conjugate region and favorable ionospheric conditions. About 63% of whistlers were correlated with lightning strokes in the vicinity of the conjugate point within spatial extent of 1000 km (conjugate area). Most (about 53%) whistlers were found to be associated with lightning strokes that were offset to the southeast of the conjugate point. The results indicate that an energy range of 7.5-17.5 kJ of lightning strokes generate most of whistlers at this station. The L shell calculations show that propagation paths of the observed whistlers were embedded in the topside ionosphere. Based on these results we suggest a possibility of ducted mode of propagation even for such very low latitude whistlers. ©2015. American Geophysical Union. All Rights Reserved

Jesuits and the Natural Sciences in Modern Times, 1814–2014

From 1814, linked to their educational work, Jesuits made significant contributions to the natural sciences, especially in the fields of astronomy, meteorology, seismology, terrestrial magnetism, mathematics, and biology in a worldwide network of universities, secondary schools and observatories.; Readership: All interested in the history of Jesuits and their contribution to the natural sciences, in science and religion and in general in the history of science

Lithosphere Structure and upper mantle characteristics below the Bay of Bengal

The oceanic lithosphere in the Bay of Bengal (BOB) formed 80–120 Ma following the breakup of eastern Gondwanaland. Since its formation, it has been affected by the emplacement of two long N-S trending linear aseismic ridges (85oE and Ninetyeast) and by the loading of ca. 20-km of sediments of the Bengal Fan. Here, we present the results of a combined spatial and spectral domain analysis of residual geoid, bathymetry and gravity data constrained by seismic reflection and refraction data. Self-consistent geoid and gravity modeling defined by temperature-dependent mantle densities along a N-S transect in the BOB region revealed that the depth to the Lithosphere-Asthenosphere boundary (LAB) deepens steeply from 77 km in the south to 127 km in north, with the greater thickness being anomalously thick compared to the lithosphere of similar-age beneath the Pacific Ocean. The Geoid-Topography Ratio (GTR) analysis of the 85°E and Ninetyeast ridges indicate that they are compensated at shallow depths. Effective elastic thickness (Te) estimates obtained through admittance/ coherence analysis as well as the flexural modeling along these ridges led to the conclusions: i) 85°E Ridge was emplaced in off-ridge environment (Te = 10–15 km); ii) the higher Te values of ?25 km over the Afanasy Nikitin Seamount (ANS) reflect the secondary emplacement of the seamount peaks in off-ridge environment, iii) that the emplacement of the Ninetyeast Ridge north of 2°N occurred in an off-ridge environment as indicated by higher Te values (25-30 km). Furthermore, the admittance analysis of geoid and bathymetry revealed that the admittance signatures at wavelengths >800 km are compensated by processes related to upper mantle convection

Jesuits and the Natural Sciences in Modern Times, 1814–2014

From 1814, linked to their educational work, Jesuits made significant contributions to the natural sciences, especially in the fields of astronomy, meteorology, seismology, terrestrial magnetism, mathematics, and biology in a worldwide network of universities, secondary schools and observatories.; Readership: All interested in the history of Jesuits and their contribution to the natural sciences, in science and religion and in general in the history of science

Ionospheric response during Tropical Cyclones-a brief review on Amphan and Nisarga

Here, we explore the different characteristics of a possible coupling between tropospheric and ionospheric activities during the impact of tropical cyclones (TC) like Amphan and Nisarga in the Indian subcontinent. We have analyzed the effect of TCs Amphan and Nisarga on the low latitude ionosphere using the measurements from several IGS stations around India and a GPS+ NavIC station in Indore, India. For the first time, this study assesses the impact of tropical cyclones on the equatorial ionosphere using both GPS and NavIC. After the landfall of TC Amphan, the VTEC analysis shows a significant drop from nominal values in both NavIC as well in GPS by $5.1$ TECU and $3.6$ TECU, respectively. In contrast to TC Amphan, Nisarga showed a rise in VTEC which ranged from $0.9$ TECU in GPS to $1.7$ - $5$ TECU in NavIC satellites except for PRN6. The paper examines Outgoing Longwave Radiation as a proxy to the convective activity which may be responsible for the ionospheric variation through the generation of gravity waves. In addition, the horizontal neutral wind observations at the location of TC landfall confirm the presence of ionospheric disturbances. VTEC perturbation analysis using a band-pass filter reveals a variation in differential TEC values between $\pm0.4$ and $\pm0.8$ based on the IGS station measurements. This indicates that the gravity wave is one of the responsible mechanisms for the lower-upper atmospheric coupling during both cyclones

Research Contribution of major Centrally Funded Institution Systems of India

India is now among the major knowledge producers of the world, ranking among the top 5 countries in total research output, as per some recent reports. The institutional setup for Research & Development (R&D) in India comprises a diverse set of Institutions, including Universities, government departments, research laboratories, and private sector institutions etc. It may be noted that more than 45% share of India's Gross Expenditure on Research and Development (GERD) comes from the central government. In this context, this article attempts to explore the quantum of research contribution of centrally funded institutions and institution systems of India. The volume, proportionate share and growth patterns of research publications from the major centrally funded institutions, organised in 16 groups, is analysed. These institutions taken together account for 67.54% of Indian research output during 2001 to 2020. The research output of the centrally funded institutions in India has increased steadily since 2001 with a good value for CAGR. The paper presents noteworthy insights about scientific research production of India that may be useful to policymakers, researchers and science practitioners in India. It presents a case for increased activity by the state governments and private sector to further the cause of sustainable and inclusive research and development in the country