Earth system curator: metadata infrastructure for climate modeling

The Earth System Curator is a National Science Foundation sponsored project developing a metadata formalism for describing the digital resources used in climate simulations. The primary motivating observation of the project is that a simulation/model’s source code plus the configuration parameters required for a model run are a compact representation of the dataset generated when the model is executed. The end goal of the project is a convergence of models and data where both resources are accessed uniformly from a single registry. In this paper we review the current metadata landscape of the climate modeling community, present our work on developing a metadata formalism for describing climate models, and reflect on technical challenges we have faced that require new research in the area of Earth Science Informatics.     

Response of multilayer geosynthetic-reinforced bed resting on soft soil with stone columns

In the present study, a mechanical model has been developed to study the behavior of multilayer geosynthetic-reinforced granular fill over stone column-reinforced soft soil. The granular fill and geosynthetic reinforcement layers have been idealized by Pasternak shear layer and rough elastic membranes, respectively. The Kelvin–Voight model has been used to represent the time-dependent behavior of saturated soft soil. The stone columns are idealized by stiffer springs and assumed to be linearly elastic. The nonlinear behavior of the soft soil and granular fill is considered. The effect of consolidation of soft soil due to inclusion of the stone columns on settlement response has also been included in the model. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution and results are presented in nondimensional form. It has been observed that if the soft soil is improved with stone columns, the multilayer reinforcement system is less effective as compared to single layer reinforcement to reduce the total settlement as there is considerable reduction in the total settlement due to stone column itself. Multilayer reinforcement system is effective for reducing the total settlement when stone columns are not used. However, multilayer reinforcement system is effective to transfer the stress from soil to stone column. The differential settlement is also slightly reduced due to application of multiple geosynthetic layers as compared to the single layer reinforcement system.     

Thermogravimetric and model-free kinetic studies on CO<Subscript>2</Subscript> gasification of low-quality,high-sulphur Indian coals

Coal gasification with CO₂ has emerged as a cleaner and more efficient way for the production of energy, and it offers the advantages of CO₂ mitigation policies through simultaneous CO₂ sequestration. In the present investigation, a feasibility study on the gasification of three low-quality, high-sulphur coals from the north-eastern region (NER) of India in a CO₂ atmosphere using thermogravimetric analysis (TGA-DTA) has been made in order to have a better understanding of the physical and chemical characteristics in the process of gasification of coal. Model-free kinetics was applied to determine the activation energies (E) and pre-exponential factors (A) of the CO₂ gasification process of the coals. Multivariate non-linear regression analyses were performed to find out the formal mechanisms, kinetic model, and the corresponding kinetic triplets. The results revealed that coal gasification with CO₂ mainly occurs in the temperature range of 800^°–1400^°C and a maximum of at around 1100^°C. The reaction mechanisms responsible for CO₂ gasification of the coals were observed to be of the ‘nth order with autocatalysis (CnB)’ and ‘nth order (Fn) mechanism’. The activation energy of the CO₂ gasification was found to be in the range 129.07–146.81 kJ mol^?1.     

<Emphasis Type="Italic">Holigarna</Emphasis> (Anacardiaceae) from the early Eocene of Western India and its palaeogeographical and palaeoclimatological significance

Thick lignite deposits on the western margin of India were preserved on account of thick vegetation which got buried underneath due to tectonic activities that occurred in northwestern part of India during the early Palaeogene. Study of the fossil flora preserved in these beds is important to deduce the palaeoclimate of the region. Therefore, a field work was undertaken to collect plant fossils from the Tarkeshwar lignite mine, Surat district, Gujarat (western India) which is still unexplored as far as the plant mega-remains are concerned. A fossil wood is systematically described from the Cambay Shale Formation of the mine considered to be of early Eocene in age. It shows close affinities with Holigarna (Anacardiaceae), particularly with H. beddomei and H. grahamii. This genus is evergreen in nature and grows in the Indo-Malayan region, while both the modern analogues of the fossil are endemic to semi-evergreen to evergreen forests ofWestern Ghats, south India, located at the equator. This not only confirms the palaeolatitudinal position of the Indian subcontinent at the equator during the early Palaeogene, but also indicates the presence of equatorial rain forest in the Indian subcontinent during the period. Based on the timetree, Sapindales started to diverge in the early Palaeocene (62–57 Ma) as its oldest fossil is from the K-Pg boundary. Discovery of the present anacardiaceous fossil (belonging to Sapindales) from the early Eocene strengthens the above phylogenetic view.     

Tunneling in lesser Himalaya,Jammu and Kashmir,India with special emphasis on tectonic mélange

Himalayan fold belt has full of geological surprises, ‘mélange’ is one of them which create difficulties during tunneling. Such mélange completely went unnoticed during surface mapping and geotechnical investigation preceding the construction of the Udhampur railway tunnel (URT). During the construction, the mélange zone has encountered across the tunnel, which occurs along the Tanhal thrust (equivalent to MBT) that separates the Murree Group and the Shiwalik Group. The mélange was characterized by a chaotic, heterogeneous geological mixture of stronger blocks (scale independence) and weaker sheared fine-grained matrix, often termed as “block-in-matrix rocks” or bimrocks, which enforced mixed face tunneling. The heterogeneity in a tectonic mélange led to stress concentrations in the rock blocks, and there were relatively high deformations within the matrix also. Release of stress from the blocks due to excavation, with unfavorable joint and thrust orientations enforced brittle failure of the blocks (face and crown collapses) while matrix deformation (time dependent) caused convergence of primary support later. Additionally, the clay minerals with high swelling potential within the matrix swelled and created pressure on the primary support. Due to the geomechanical heterogeneity in mélange, homogenizing the rock-mass by the commonly used quantitative systems might have lead to an inappropriate design and construction. The adopted New Austrian Tunneling Method (NATM) proved to be an useful tool for tunneling.     

Long period Pc5 pulsations

The characteristics of long period Pc5 pulsations (frequency 3·33-1·67 mHz; period 300–600 sec) for stations in the subauroral, auroral and polar zones are studied for 1967. These pulsations occur mainly in the auroral and polar zones with one morning and one evening peak; in the cusp region they occur most frequently near local noon. The evening peak gets stronger and appears farther away from noon with increasing geomagnetic activity. Periods are shorter and amplitudes larger in the morning compared to the evening hours. Only in a small latitudinal belt (60–70°) do the periods tend to increase with latitude. Amplitudes are almost always maximum near the central line of the auroral zone and drop much more sharply towards lower latitudes than towards higher latitudes. Considerable diurnal variations and also variations with magnetic activity are found to exist in the occurrence-latitude and amplitudelatitude profiles. In all the three regions the occurrence and the amplitude of these pulsations increase with magnetic activity to a certain level after which results become uncertain. Periods either do not change very much or at some stations decrease as activity increases.     

Living planktonic foraminifera during the late summer monsoon period in the Arabian Sea

During the late summer monsoon living planktonic foraminifera were collected in the southeastern Arabian Sea between 3°N and 15°N by using six vertical plankton tows. Sixteen species of planktonic foraminifera were identified. Among them, Globigerinoides ruber and Globigerinoides sacculifer are the most abundant species, while the ecologically most important species Globigerina bulloides is very rare. The low abundance of G. bulloides can be explained by the warming of the surface water in combination with deepening of the mixed layer, since this species preferentially dwells in nutrient-rich upwelling waters. The population density of planktonic foraminifera ranges between 31 and 185 specimens per 10⁻³ m³. The low absolute numbers of planktonic foraminifera are similar to the numbers which were reported before from the non-upwelling areas in the Arabian Sea. The low absolute numbers and the collected foraminiferal assemblages are therefore highly indicative of the Arabian Sea non-upwelling areas. Particularly significant are the low absolute and relative numbers of the non-spinose species Globorotalia menardii and Neogloboquadrina dutertrei. The absence of these species indicate the relatively low nutrient levels in this area at the tail end of the summer monsoon period.     

Tsunami Wave Interaction with Data Buoys

To plan for proper mitigation measures, one should have an advanced knowledge of the phenomenon of tsunami propagation from the deep ocean to coastal waters. There are a few methods to predict tsunamis in the ocean waters; one method is the effective use of data buoy measurements. Although data buoys have been used along the Indian waters there has been a tremendous growth in the number of buoy deployment recently. Under the National Data Buoy Programme (NDBP) of India, the 2.2 m diameter discus data buoys were deployed along the east and west coasts of India for measuring meteorological and ocean parameters. It would be advantageous if these buoys could be efficiently used to measure rare events such as tsunamis. Understanding the dynamic behavior of the buoy is of prime importance if a tsunami warning system is to be successful. This may be accomplished through experimental or numerical studies. A comprehensive experimental study has been conducted to understand the dynamic behavior of a wave rider buoy exposed to a variety of waves. It is common that tsunami waves are represented in terms of shallow water waves, namely solitary and cnoidal waves. Hence, in the present study, the discus type data buoy is scale modeled and tested under the action of solitary and cnoidal waves in the laboratory. The time histories of wave elevations, as well as heave and pitch motions of the buoy model, were analyzed through a spectral approach as well as through wavelet transformations. The wavelet approach gives more detailed insight into the spectral characteristics of the buoy motion in the time scale. The harmonic analyses were performed for the cnoidal wave elevations and subsequent motion characteristics that give an insight into the energy variations. The details of the model, instrumentation, testing conditions and the results are presented in this paper.