Providing new homes for climate change exiles

Abstract

Given a certain pre-existing commitment to sea-level rise due to the long thermal lags of the ocean system, several million people living in coastal areas and small islands will inevitably be displaced by the middle of the century. These climate exiles will have nowhere to go. Rather than deal with this in an ad hoc manner as the problem arises, the authors propose a mechanism by which these exiles would be given immigration benefits by countries through a formula that ties numbers of immigrants to a country's historical greenhouse gas emissions. Such a compensatory mechanism appears to be a fair way of addressing the problems faced by climate exiles.     

Effect of the variation in the lower tropospheric temperature on the wind onset of the Indian summer monsoon

There is a large thermal contrast between the Arabian Peninsula and India (Δθ _AI) at the mature stage of the Indian summer monsoon (ISM). The forming process of Δθ _AI is investigated analyzing various datasets. It forms earlier in the lower troposphere than in the middle and upper layers. The potential temperature in the lower troposphere over the west coast of India (θ _IW) abruptly decreases in advance of the rapid enhancement of the westerly wind over the Arabian Sea corresponding to the ISM onset. Such a process was observed for all the target years and the rapid decrease in θ _IW could trigger the ISM onset. The decrease in θ _IW had two patterns. In one case, cooler air is brought by the strong winds around a cyclone over the Arabian Sea. In another case, θ _IW decreases gradually by a synergy of a southwesterly wind over the Arabian Sea and the enlargement of Δθ _AI.     

Neon and argon in the Allende meteorite

Trapped and cosmogenic Ne and Ar were measured in Ca,Al-rich aggregates and chondrules, mafic chondrules, and bulk and matrix samples from the Allende C3V chondritic meteorite to investigate the possible occurrence of anomalous isotopic compositions of noble gases that would correlate with oxygen or magnesium isotopic anomalies previously found in this meteorite.Large enrichments of both ²²Ne and ³⁶Ar were observed in low-temperature release fractions from several Ca,Al-rich inclusions, but the enrichments are consistent with galactic cosmic-ray production of ²²Ne by spallation from sodium and ³⁶Ar by neutron capture on chlorine. Trapped neon in matrix samples is comprised of two distinctive compositions, with (²⁰Ne/²²Ne)_t equal to 8.7 ± 0.1 and 10.4 ± 1.0, that appear to correlate with the two gas-rich trace phases chromite/carbon and ‘Q’ described by Lewis et al. (1975). Several Ca,Al-rich aggregates which have high contents of the volatile elements Na, Cl, K, and Rb also contain trapped neon. However, no neon-E has been identified in any of the samples studied, including samples of several inclusions known to contain isotopically anomalous oxygen and magnesium.     

Combined magnetic,electrostatic, and gravity separation techniques for recovering strategic heavy minerals from beach sands

A combination of unit operations like gravity, magnetic, and electrostatic separation techniques were applied to separate strategic heavy minerals from bulk samples taken from two coastal stretches of Kappil-Varkala (KV) and Shanghumugham-Kovalam (SK) in Thiruvananthapuram, south Kerala, India. On processing the feed, the concentrate obtained contains 67.3% THM for KV and 65.15% THM for SK, out of which ilmenite predominantly exists with a yield of 45.55 and 43.6% in weight followed by other minerals like sillimanite, monazite, zircon, rutile, leucoxene, and garnet. Analysis indicates that judicious combination of unit operations like gravity, magnetic, and electrostatic separation techniques can efficiently recover heavy mineral species even from placers of smaller deposit.     

A bounding-based solution approach for the continuous arc covering problem

Road segments, telecommunication wiring, water and sewer pipelines, canals and the like are important features of the urban environment. They are often conceived of and represented as network-based arcs. As a result of the usefulness and significance of arc-based features, there is a need to site facilities along arcs to serve demand. Examples of such facilities include surveillance equipment, cellular towers, refueling centers and emergency response stations, with the intent of being economically efficient as well as providing good service along the arcs. While this amounts to a continuous location problem by nature, various discretizations are generally relied upon to solve such problems. The result is potential for representation errors that negatively impact analysis and decision making. This paper develops a solution approach for the continuous arc covering problem that theoretically eliminates representation errors. The developed approach is applied to optimally place acoustic sensors and cellular base stations along a road network. The results demonstrate the effectiveness of this approach for ameliorating any error and uncertainty in the modeling process.     

Offshore Extension of Deccan Traps in Kachchh,Central Western India: Implications for Geological Sequestration Studies

The Deccan basalts in central western India are believed to occupy large onshore–offshore area. Using geophysical and geological observations, onshore sub-surface structural information has been widely reported. On the contrary, information about offshore structural variations has been inadequate due to scarcity of marine geophysical data and lack of onshore–offshore lithological correlations. Till date, merely a few geophysical studies are reported that gauge about the offshore extent of Deccan Traps and the Mesozoic sediments (pre-Deccan). To fill this gap in knowledge, in this article, we present new geophysical evidences to demonstrate offshore continuation of the Deccan volcanics and the Mesozoic sediments. The offshore multi-channel seismic and onshore–offshore lithological correlations presented here confirm that the Mesozoic sedimentary column in this region is overlain by 0.2–1.2-km-thick basaltic cover. Two separate phases of Mesozoic sedimentation, having very distinctive physical and lithological characteristics, are observed between overlying basaltic rocks and underlying Precambrian basement. Using onshore–offshore seismic and borehole data this study provides new insight into the extent of the Deccan basalts and the sub-basalt structures. This study brings out a much clearer picture than that was hitherto available about the offshore continuation of the Deccan Traps and the Mesozoic sediments of Kachchh. Further, its implications in identifying long-term storage of anthropogenic CO₂ within sub-basalt targets are discussed. The carbon sequestration potential has been explored through the geological assessment in terms of the thickness of the strata as well as lithology.     

Space-based aperture array for ultra-long wavelength radio astronomy

The past decade has seen the advent of various radio astronomy arrays, particularly for low-frequency observations below 100 MHz. These developments have been primarily driven by interesting and fundamental scientific questions, such as studying the dark ages and epoch of re-ionization, by detecting the highly red-shifted 21 cm line emission. However, Earth-based radio astronomy observations at frequencies below 30 MHz are severely restricted due to man-made interference, ionospheric distortion and almost complete non-transparency of the ionosphere below 10 MHz. Therefore, this narrow spectral band remains possibly the last unexplored frequency range in radio astronomy. A straightforward solution to study the universe at these frequencies is to deploy a space-based antenna array far away from Earths’ ionosphere. In the past, such space-based radio astronomy studies were principally limited by technology and computing resources, however current processing and communication trends indicate otherwise. Furthermore, successful space-based missions which mapped the sky in this frequency regime, such as the lunar orbiter RAE-2, were restricted by very poor spatial resolution. Recently concluded studies, such as DARIS (Disturbuted Aperture Array for Radio Astronomy In Space) have shown the ready feasibility of a 9 satellite constellation using off the shelf components. The aim of this article is to discuss the current trends and technologies towards the feasibility of a space-based aperture array for astronomical observations in the Ultra-Long Wavelength (ULW) regime of greater than 10 m i.e., below 30 MHz. We briefly present the achievable science cases, and discuss the system design for selected scenarios such as extra-galactic surveys. An extensive discussion is presented on various sub-systems of the potential satellite array, such as radio astronomical antenna design, the on-board signal processing, communication architectures and joint space-time estimation of the satellite network. In light of a scalable array and to avert single point of failure, we propose both centralized and distributed solutions for the ULW space-based array. We highlight the benefits of various deployment locations and summarize the technological challenges for future space-based radio arrays.     

On the irradiation history and origin of gas-rich meteorites

With the transmission electron microscope, we have made detailed studies of the track density gradients and irradiation geometries of track-rich grains and chondrules in sections of Fayetteville and Kapoeta. We have made the same type of studies in sections of lunar breccias and grains from lunar soil for comparison.A substantial fraction (50–90 per cent) of the meteoritic track-rich grains and chondrules show evidence of having been irradiated anisotropically in their different faces, as would be expected for irradiation on the surface of a parent body. Our observations thus support the hypothesis that the irradiation of these grains and chondrules took place on the regoliths of asteroidal-sized bodies.Measurement of steepest track density gradients indicate that while there are finite differences between spectra exhibited by individual gas-rich meteorites, the average solar flare spectral shapes have been similar over the last ~4 b.y. or so.