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91.
ABSTRACTThe administration of U.S. President Donald Trump has promised to stop the ongoing spiralling down of the U.S. coal industry. We discuss the origins of the decline and assess the effects of policy interventions by the Trump administration. We find that, with fierce competition from natural gas and renewables, a further decrease of coal consumption must be expected by the old and inefficient U.S. coal-fired electricity generation fleet. By contrast, we consider the overly optimistic (for coal producers) view of the U.S. Energy Information Agency, and test whether the tide for the U.S. coal industry could turn as a result of three potential support measures: (i) revoking the Clean Power Plan (CPP); (ii) facilitating access to the booming Asian market; and (iii) enhanced support for Carbon Capture, Transport and Storage (CCTS) technology. We investigate the short-term and long-term effects on U.S. coal production using a comprehensive partial equilibrium model of the world steam coal market, COALMOD-World (Holz, Haftendorn, Mendelevitch, & von Hirschhausen, 2016). We find that revoking the CPP could stop the downward trend of steam coal consumption in the U.S., but even allowing for additional exports, will not lead to a return of U.S. coal production to the levels of the 2000s, that is, over 900?Mt per year. When global steam coal use is aligned with the 2°C climate target, U.S. steam coal production drops to around 100?Mt per year by 2030 and below 50?Mt by 2050, even if CCTS is available and exports via the U.S. West Coast is possible.Key policy insights
Declining U.S. coal use is primarily caused by competition from natural gas and renewables not by environmental regulation of the coal sector.
Without substantial policy support, U.S. coal-fired generation capacity will continue to decline rapidly.
Revoking the Clean Power Plan will lead to about one eighth higher U.S. coal production in the next years.
Carbon Capture, Transport and Storage does not prevent the rapid decline of coal use required under stringent climate policy.
Even in the most extreme pro-coal scenarios with additional export possibilities, U.S. coal production will not return to its pre-2010 levels.
92.
Climate Dynamics - Recent work has identified potential multi-year predictability in soil moisture (Chikamoto et al. in Clim Dyn 45(7–8):2213–2235, 2015). Whether this long-term... 相似文献
93.
Roman Tomaschitz 《Astrophysics and Space Science》2011,331(2):397-408
The effect of a cosmic time variation of Newton’s constant on galactic angular diameters, linear size, apparent magnitude,
and surface brightness is investigated. The redshift scaling of the gravitational constant is proportional to the Hubble parameter,
derived from the constancy of a moderate dimensionless ratio of fundamental constants, and manifested in galactic linear-size
evolution. The latter is demonstrated by fitting the angular size–redshift relation to spectroscopically and photometrically
selected samples of high-redshift rotators. The intrinsic luminosity evolution of the rotators and their magnitude–redshift
and surface brightness–redshift relations are studied. The galactic luminosity scales with a power of the Hubble parameter,
and the scaling exponent is inferred from a moderate dimensionless ratio involving the gravitational constant, the Galactic
luminosity, and the velocity of the Galaxy in the microwave background. The fits are performed with a cosmic expansion factor
derived from paleoplanetary surface temperatures. This expansion factor is tested by comparing the corresponding redshift
evolution of the angular-size distance to the distance estimates of two samples of galaxy clusters. 相似文献
94.
Roman V. Baluev 《Celestial Mechanics and Dynamical Astronomy》2011,111(1-2):235-266
We use full available array of radial velocity data, including recently published HARPS and Keck observatory sets, to characterize the orbital configuration of the planetary system orbiting GJ876. First, we propose and describe in detail a fast method to fit perturbed orbital configuration, based on the integration of the sensitivity equations inferred by the equations of the original N-body problem. Further, we find that it is unsatisfactory to treat the available radial velocity data for GJ876 in the traditional white noise model, because the actual noise appears autocorrelated (and demonstrates non-white frequency spectrum). The time scale of this correlation is about a few days, and the contribution of the correlated noise is about 2 m/s (i.e., similar to the level of internal errors in the Keck data). We propose a variation of the maximum-likelihood algorithm to estimate the orbital configuration of the system, taking into account the red noise effects. We show, in particular, that the non-zero orbital eccentricity of the innermost planet d, obtained in previous studies, is likely a result of misinterpreted red noise in the data. In addition to offsets in some orbital parameters, the red noise also makes the fit uncertainties systematically underestimated (while they are treated in the traditional white noise model). Also, we show that the orbital eccentricity of the outermost planet is actually ill-determined, although bounded by ~0.2. Finally, we investigate possible orbital non-coplanarity of the system, and limit the mutual inclination between the planets b and c orbits by 5°?C15°, depending on the angular position of the mutual orbital nodes. 相似文献
95.
The regularization of a new problem, namely the three-body problem, using ‘similar’ coordinate system is proposed. For this
purpose we use the relation of ‘similarity’, which has been introduced as an equivalence relation in a previous paper (see
Roman in Astrophys. Space Sci. doi:, 2011). First we write the Hamiltonian function, the equations of motion in canonical form, and then using a generating function,
we obtain the transformed equations of motion. After the coordinates transformations, we introduce the fictitious time, to
regularize the equations of motion. Explicit formulas are given for the regularization in the coordinate systems centered
in the more massive and the less massive star of the binary system. The ‘similar’ polar angle’s definition is introduced,
in order to analyze the regularization’s geometrical transformation. The effect of Levi-Civita’s transformation is described
in a geometrical manner. Using the resulted regularized equations, we analyze and compare these canonical equations numerically,
for the Earth-Moon binary system. 相似文献
96.
Basing on the Asymmetric Continuum Theory, we develop the thermodynamics including fragmentation spin fracture processes; applications for the earthquake source processes are considered. The fracture band model is used to describe a dislocation and disclination superlattice. The Gibbs free energy of defect formation is specified. A dynamic spin fracture criterion was formulated. Consequently, a dynamic model of rock fracture employing dislocations, disclinations, and cracks was constructed to describe slip and fragmentation fracture processes in the earthquake sources. 相似文献
97.
Nikolai F. Zobov Sergei V. Shirin Roman I. Ovsyannikov Oleg L. Polyansky Robert J. Barber Jonathan Tennyson Peter F. Bernath Michel Carleer Reginald Colin Pierre-François Coheur 《Monthly notices of the Royal Astronomical Society》2008,387(3):1093-1098
The high resolution laboratory spectrum of hot water vapour has been recorded in the 500–13 000 cm−1 wavenumber range and we report on the analysis of the 4750–13 000 cm−1 (0.769–2.1 μm) portion. The emission spectrum was recorded using an oxy-acetylene welding torch and a Fourier transform spectrometer. Line assignments in the laboratory spectrum as well as in an absorption spectrum of a sunspot umbra were made with the help of the BT2 line-list. Our torch spectrum is the first laboratory observation of the 9300 Å'steam bands' seen in M-stars and brown dwarfs. 相似文献
98.
99.
100.
Stefan Emeis Klaus Sch?fer Christoph Münkel Roman Friedl Peter Suppan 《Boundary-Layer Meteorology》2012,143(1):25-35
Since 2006 different remote monitoring methods for determining mixing-layer height have been operated in parallel in Augsburg
(Germany). One method is based on the operation of eye-safe commercial mini-lidar systems (ceilometers). The optical backscatter
intensities recorded with ceilometers provide information about the range-dependent aerosol concentration; gradient minima
within this profile mark the tops of mixed layers. Special software for these ceilometers provides routine retrievals of lower
atmospheric layering. A second method, based on sodar observations, detects the height of a turbulent layer characterized
by high acoustic backscatter intensities due to thermal fluctuations and a high variance of the vertical velocity component.
This information is extended by measurements with a radio-acoustic sounding system (RASS) that directly provides the vertical
temperature profile from the detection of acoustic signal propagation and thus temperature inversions that mark atmospheric
layers. Ceilometer backscatter information is evaluated by comparison with parallel measurements. Data are presented from
2 years of combined ceilometer and RASS measurements at the same site and from comparison with a nearby (60 km) radiosonde
for larger-scale humidity information. This evaluation is designed to ensure mixing-layer height monitoring from ceilometer
data more reliable. 相似文献