Modeling India’s Coal Production with a Negatively Skewed Curve-Fitting Model

India’s coal demand is forecast to increase at a rapid pace in the future due to the country’s economic and population growth. Analyzing the scope for future production of India’s domestic coal resources, therefore, plays a vital role in the country’s development of sound energy policies. This paper presents a quantitative scenario analysis of India’s potential future coal production by using a negatively skewed curve-fitting model and a range of estimates of the country’s ultimately recoverable resources (URR) of coal. The results show that the resource base is sufficient for India’s coal production to keep increasing over the next few decades, to reach between 2400 and 3200 Mt/y at 2050, depending on the assumed value of URR. A further analysis shows that the high end of this range, which corresponds to our ‘GSI’ scenario, can be considered as the probable upper-bound to India’s domestic coal production. Comparison of production based on the ‘GSI’ scenario with India’s predicted demand shows that the domestic production of coal will be insufficient to meet the country’s rising coal demand, with the gap between demand and production increasing from its current value of about 268 Mt/y to reach 300 Mt/y in 2035, and 700 Mt/y by 2050. This increasing gap will be challenging for the energy security of India.     

Modeling global Hammond landform regions from 250‐m elevation data

In 1964, E.H. Hammond proposed criteria for classifying and mapping physiographic regions of the United States. Hammond produced a map entitled “Classes of Land Surface Form in the Forty‐Eight States, USA”, which is regarded as a pioneering and rigorous treatment of regional physiography. Several researchers automated Hammond?s model in GIS. However, these were local or regional in application, and resulted in inadequate characterization of tablelands. We used a global 250 m DEM to produce a new characterization of global Hammond landform regions. The improved algorithm we developed for the regional landform modeling: (1) incorporated a profile parameter for the delineation of tablelands; (2) accommodated negative elevation data values; (3) allowed neighborhood analysis window (NAW) size to vary between parameters; (4) more accurately bounded plains regions; and (5) mapped landform regions as opposed to discrete landform features. The new global Hammond landform regions product builds on an existing global Hammond landform features product developed by the U.S. Geological Survey, which, while globally comprehensive, did not include tablelands, used a fixed NAW size, and essentially classified pixels rather than regions. Our algorithm also permits the disaggregation of “mixed” Hammond types (e.g. plains with high mountains) into their component parts.     

Policy Drivers of U.S. Wetland Conversion Rates, 1955–2009

While conversion of wetlands to nonagricultural purposes has persisted, the five U.S. national wetland inventory reports spanning 1955–2009 show a large decline in the rate of conversion of wetlands for agriculture, especially from the mid-1970s to the mid-1990s. Through regression and path analysis, this study identifies primary policy and economic drivers of this decline in wetland conversions. The Clean Water Act §404 is strongly and negatively related to conversion rates. Crop prices affect wetland conversions both directly, by influencing returns to investments for conversion, and indirectly, by influencing Conservation and Wetland Reserve Program enrollments as well as the regulatory impact of Swampbuster. Along with the proportion of wetlands remaining, these factors explain 90–94% of the annual variation in total wetland conversions, agricultural conversions, and conversion of forested and emergent wetlands.     

Large-eddy simulations of the effects of hilly terrain on the convective boundary layer

Large-eddy simulations of the convective boundary layer are compared over hilly versus flat surfaces. Moderate values for the height and horizontal spacing of the hills were selected. Thermally-direct hill-valley circulations are induced by the uneven terrain, accounting for a significant fraction of the resolved energy in the boundary-layer eddies. The probability of upward eddy motion reaches up to 70% over the hilltops and down to 15% over the valleys. Above-average values of both subgrid scale turbulent kinetic energy and upward eddy heat transport are found above the higher terrain. Horizontal spectra of vertical motion are strongly biased toward the horizontal scales of the terrain. Vertical profiles of atmospheric variables obtained by horizontal averaging, however, exhibit no significant differences between hilly and flat terrain simulations.     

Mantle plumes control magnetic reversal frequency

Magnetic reversal frequency correlates inversely with mantle plume activity for the past 150 Ma, as measured by the volume production rate of oceanic plateaus, seamount chains, and continental flood basalts. This inverse correlation is especially striking during the long Cretaceous magnetic normal “superchron”, when mantle plume activity was at a maximum. We suggest that mantle plumes control magnetic reversal frequency by the following sequence of events. Mantle plumes rise from theD″ seismic layer just above the core/mantle boundary, thinningD″ to fuel the plumes. This increases core cooling by allowing heat to be conducted more rapidly across the core/mantle boundary. Outer core convective activity then increases to restore the abnormal heat loss, causing a decrease in magnetic reversal frequency in accord with model predictions for bothα² andαω dynamos. When core convective activity increases above a critical level, a magnetic superchron results. The pulse of plume activity that caused the Cretaceous superchron resulted in a minimum increase in core heat loss of about 1200 GW over the present-day level, which corresponds to an increase in Joule heat production of about 120 GW within the core.     

Venusian highlands: geoid to topography ratios and their implications

Using Pioneer Venus line-of-sight gravity data and orbit simulation procedures, we have estimated apparent depths of isostatic compensation (ADCs) for twelve Venusian highland features: Asteria, Atla, Bell, Beta, Ovda, Phoebe, Tellus, Thetis and Ulfrun Regiones, and Nokomis, Gula and Sappho Montes. ADCs range from 50 km to 270 km; half of the values are less than 100 km. Using these ADCs, we estimate geoid to topography ratios (GTRs) for each area to allow comparison with convection calculations and with terrestrial data for oceanic hot spots, swells and plateaus. The geoid is estimated in the wavenumber domain from the isostatic formula, using the topography and ADC for each region. In the space domain, the GTR is equal to the least squares slope of the linear fit of the geoid to the topography. The resulting GTR range is 7–31 m/km, which is much higher than terrestrial oceanic values (−1 to 5 m/km). The features fall into two distinct groups, one with a GTR range of 7–13 m/km, and one with a range of 19–25 m/km. The exception is Beta Regio, which has a GTR of 31 m/km. A model for thermal thinning of a 100 km thick lithosphere fits all values in the lower GTR group to within one standard deviation. Airy compensation could also be present, but cannot fully compensate these features. Partial dynamic compensation of the lower GTR group in combination with lithospheric mechanisms is also possible, but not required to fit the data. The upper GTR range, 19–25 m/km, can be fit with an upper mantle, constant viscosity convection model. The large GTR values are inconsistent with the presence of a low viscosity zone. If more than one compensation mechanism is present in the regions in the higher GTR group, the GTRs will be underestimated in terms of a dynamic interpretation. We thus fit the convection models to the upper end of the GTR range, 25 m/km. Rayleigh numbers in the range 10⁴–10⁶ will produce a GTR of 25 m/km when combined with conductive lid thicknesses of 85–150 km. The 6 m/km range in both of the GTR groups is probably due to varying degrees of crustal and thermal compensation, combined with dynamic compensation in the upper GTR group. The difference between terrestrial and Venusian GTR ranges can be explained largely by the lack of a low viscosity zone on Venus.     

Segmentation of alluvial fans in death valley,california: New insights from surface exposure dating and laboratory modelling

Laboratory experiments, recent paleoenvironmental analyses of rock varnish, and surface exposure dating of geomorphic units have led to new insights into the process of entrenchment and segmentation of alluvial fans, and into the history of Quaternary sedimentation in Death Valley. Entrenchment begins at the fanhead. As the trench deepens, its down-slope end migrates down-fan, taking several tens of thousands of years to reach lower parts of the fan. Laboratory experiments suggest, however, that a new segment begins to grow at the toe long before the trench reaches this part of the fan. Furthermore, the initial slope of the segment is not the equilibrium slope. Field evidence supports this model. The tectonic tilting that caused entrenchment and segmentation in Death Valley may have been triggered by loading of the valley with water. Sedimentation on the salt pan in southern Death Valley is not, at present, in equilibrium with that on the fans. Rather, it seems to be adjusting to an increase in the amount of fine material reaching the playa, due in part to breaching of the outlet of Lake Tecopa somewhat after 600 ka BP, and in part to subsidence of different parts of the valley at different rates. Failure to recognize this disequilibrium resulted in errors in earlier estimates of the age of the segmentation events.     

The validation of various schemes for parameterizing evaporation from bare soil for use in meteorological models: A numerical study using in situ data

Parameterization of evaporation from a non-plant-covered surface is very important in the hierarchy strategy of modelling land surface processes. One of the representations frequently used in its computation is the resistance formulation. The performance of the evaporation schemes using the , , and their combination resistance approaches to parameterize evaporation from bare soil surfaces is discussed. For that purpose, the nine schemes, based on a different dependence of and on volumetric soil moisture content and its saturated value, are used.The tests of performances of the considered schemes are based on time integrations by the land surface module (BARESOIL) using observed data. The 23 data sets at a bare surface experimental site in Rimski anevi, Yugoslavia on chernozem soil, were used for the resistance algorithm evaluation. The quality of the schemes was compared with the observed values of the latent heat flux using several statistical parameters.     

Information infrastructure for Australia’s Integrated Marine Observing System

Australia’s Integrated Marine Observing System (IMOS, imos.org.au) is research infrastructure to establish an enduring observing program for Australian oceanic waters and shelf seas. The observations cover physical, biological, and chemical variables to address themes of multi-decadal ocean change, climate variability and weather extremes, boundary currents and inter-basin flows, continental shelf processes and ecosystem responses.IMOS observations are collected by national facilities based on various platform types and operated by partner institutions around the country. In this paper we describe the infrastructure and workflows developed to manage and distribute the data to the public. We highlight the existing standards and open-source software we have adopted, and the contributions we have made. To demonstrate the value of this infrastructure we provide some illustrations of use and uptake.All IMOS data are freely and openly available to the public via the Ocean Portal (https://imos.aodn.org.au). All IMOS-developed software is open-source and accessible at https://github.com/aodn.