An Overview of Terrestrial Sequestration of Carbon Dioxide: the United States Department of Energy's Fossil Energy R&D Program

Increasing concentrations of CO₂ and other greenhouse gases (GHG) in the Earth's atmosphere have the potential to enhance the natural greenhouse effect, which may result in climatic changes. The main anthropogenic contributors to this increase are fossil fuel combustion, land use conversion, and soil cultivation. It is clear that overcoming the challenge of global climate change will require a combination of approaches, including increased energy efficiency, energy conservation, alternative energy sources, and carbon (C) capture and sequestration. The United States Department of Energy (DOE) is sponsoring the development of new technologies that can provide energy and promote economic prosperity while reducing GHG emissions. One option that can contribute to achieving this goal is the capture and sequestration of CO₂ in geologic formations. An alternative approach is C sequestration in terrestrial ecosystsems through natural processes. Enhancing such natural pools (known as natural sequestration) can make a significant contribution to CO₂ management strategies with the potential to sequester about 290 Tg C/y in U.S. soils. In addition to soils, there is also a large potential for C sequestration in above and belowground biomass in forest ecosystems.A major area of interest to DOE's fossil energy program is reclaimed mined lands, of which there may be 0.63 ×10⁶ ha in the U.S. These areas are essentially devoid of soil C; therefore, they provide an excellent opportunity to sequester C in both soils and vegetation. Measurement of C in these ecosystems requires the development of new technology and protocols that are accurate and economically viable. Field demonstrations are needed to accurately determine C sequestration potential and to demonstrate the ecological and aesthetic benefits in improved soil and water quality, increased biodiversity, and restored ecosystems.The DOE's research program in natural sequestration highlights fundamental and applied studies, such as the development of measurement, monitoring, and verification technologies and protocols and field tests aimed at developing techniques for maximizing the productivity of hitherto infertile soils and degraded ecosystems.     

The definition of mesoscale selective forecast error covariances for a limited area variational analysis

Summary ?The paper deals with an alternative formulation of the so-called NMC (National Meteorological Center, now National Centers for Environmental Prediction) statistics to compute the background error covariance matrix to be used in a mesoscale variational analysis. While the standard method uses differences of forecasts valid for the same time, but starting from different analysis times, the new formulation required the recomputation of the short-term forecast with the initial and lateral boundary data that come from the long-term run. In the frame of a limited-area model, this approach forces the error variances at large scales to decrease drastically, because those scales are controlled by the (constant data) lateral boundary coupling. As a result, the background cost function acts more scale selectively, with an emphasis on medium scales. The analysis increments obtained from the 3D-VAR system show that the analysis increments are sharper and more concentrated with the new formulation, both in single observation and in full observation experiments. This work is part of a wider project for building a variational assimilation system inside the ALADIN model. The complete system should concentrate on mesoscale features and it should not reanalyse those scales that were already treated by the global model (ARPEGE). Some difficulties and perspectives are drawn in the concluding discussion. Received February 12, 2001; revised July 24, 2001     

Geochemical and isotopic evidence for seawater contamination of the hydrothermal system of Taal Volcano, Luzon, the Philippines

 The hydrologic structure of Taal Volcano has favored development of an extensive hydrothermal system whose prominent feature is the acidic Main Crater Lake (pH<3) lying in the center of an active vent complex, which is surrounded by a slightly alkaline caldera lake (Lake Taal). This peculiar situation makes Taal prone to frequent, and sometimes catastrophic, hydrovolcanic eruptions. Fumaroles, hot springs, and lake waters were sampled in 1991, 1992, and 1995 in order to develop a geochemical model for the hydrothermal system. The low-temperature fumarole compositions indicate strong interaction of magmatic vapors with the hydrothermal system under relatively oxidizing conditions. The thermal waters consist of highly, moderately, and weakly mineralized solutions, but none of them corresponds to either water–rock equilibrium or rock dissolution. The concentrated discharges have high Na contents (>3500 mg/kg) and low SO₄/Cl ratios (<0.3). The Br/Cl ratio of most samples suggests incorporation of seawater into the hydrothermal system. Water and dissolved sulfate isotopic compositions reveal that the Main Crater Lake and spring discharges are derived from a deep parent fluid (T≈300  °C), which is a mixture of seawater, volcanic water, and Lake Taal water. The volcanic end member is probably produced in the magmatic-hydrothermal environment during absorption of high-temperature gases into groundwater. Boiling and mixing of the parent water give rise to the range of chemical and isotopic characteristics observed in the thermal discharges. Incursion of seawater from the coastal region to the central part of the volcano is supported by the low water levels of the lakes and by the fact that Lake Taal was directly connected to the China sea until the sixteenth century. The depth to the seawater-meteoric water interface is calculated to be 80 and 160 m for the Main Crater Lake and Lake Taal, respectively. Additional data are required to infer the hydrologic structure of Taal. Geochemical surveillance of the Main Crater Lake using the SO₄/Cl, Na/K, or Mg/Cl ratio cannot be applied straightforwardly due to the presence of seawater in the hydrothermal system. Received: 12 February 1997 / Accepted: 26 January 1998     

Learning in neural spatial interaction models: A statistical perspective

 In this paper we view learning as an unconstrained non-linear minimization problem in which the objective function is defined by the negative log-likelihood function and the search space by the parameter space of an origin constrained product unit neural spatial interaction model. We consider Alopex based global search, as opposed to local search based upon backpropagation of gradient descents, each in combination with the bootstrapping pairs approach to solve the maximum likelihood learning problem. Interregional telecommunication traffic flow data from Austria are used as test bed for comparing the performance of the two learning procedures. The study illustrates the superiority of Alopex based global search, measured in terms of Kullback and Leibler's information criterion. Received: December 2001 / Accepted: August 2002 The author gratefully thanks Martin Reismann (Department of Economic Geography & Geoinformatics) for his valuable research assistance.     

Dynamic fluid effects in liquid-filled flexible cylindrical tanks

The velocity potential of a compressible fluid is found by Galerkin's method. Free surface displacements and a flexible tank wall are assumed. Explicit expressions for the impulsive mass, the impulsive moment and the overturning moment are derived for wave number m = 1. In the case of m ≥ 1 the dynamic effect of the fluid is represented by a fictitious apparent mass in explicit form.     

Global momentum loss in a non-expanding Universe

Applying the basic concepts of general relativity to the global motion of a particle in a mass-filled universe leads to a loss of momentum relative to the rest frame of the Universe. This loss is caused by the different running times of the gravitational interaction quanta exchanged with masses in front and behind the moving particle, if the signal velocity is limited to the speed of light. Due to this gravitational viscosity of space, the energy of photons will be reduced with the time, and thus with the distance of the emitting source. This red shift is superimposed on the Doppler shift in an expanding universe. A discussion of the limiting case of vanishing expansion leads to predictions about mass and radius of the Universe. The value of the mass density in such a steady-state universe must be about three times the closing density discussed in Big-Bang theories. The existence of the gravitational viscosity casts severe doubts on all estimations of the age of the Universe derived from the red-shift data.     

Platinum-Group Minerals from the Durance River Alluvium,France

Summary Platinum-group minerals were discovered, during gold recovery, in the Durance river alluvium, near Peyrolles (Bouches-du-Rhône). The PGM grains (average size 130 microns) are strongly flattened (average thickness 64 microns). The PGM concentrate consists primarily of (Pt, Fe) alloys (92%), (Os, Ir, Ru) alloys (3.5%), and native gold and (Au, Cu, Ag) alloys (4.5%). The following minerals were observed: isoferroplatinum, ferroan platinum, native osmium, native iridium, iridosmine, rutheniridosmine, osmiridium, ruthenian osmium, osmian ruthenium, cuprorhodsite, guanglinite, shandite, tetrauricupride, native gold, bornite, heazlewoodite, (Pt, Pd)₂Cu₃, Pt(Cu, Au), (Ni, Pt)Sn, (Cu, Fe)_1–x (Pd, Rh, Pt)_2+xS₂, (Pt, Pd)_4–xCu₂As_1–x. Isoferroplatinum contains numerous inclusions of alloys, sulphides, arsenides, Pd-tellurides, and partly devitrified silicate glass droplets. Most of the non-silicate inclusions also exhibit a drop-like shape indicating their original entrapment in a liquid state.Cuprorhodsite crystals (up to 20 microns) are associated with bornite included in Pt₃Fe. Rarely, Pd- and Cu-sulphides, and Pd-tellurides appear in this association. Complex droplet-like arsenide inclusions in isoferroplatinum are composed of Pt bearing guanglinite and (Pt,Pd)_4+xCu₂As_1–x. Native iridium shows exsolutions of Ir-bearing isoferroplatinum and (Pt,Pd)₂Cu₃. In places, concentrations of Sn (up to 3 wt.%) were observed in (Au, Cu) alloys. Shandite and (Ni, Pt)Sn inclusions occur in (Au, Cu, Ag) alloys. Silicate-glass inclusions are TiO₂-poor and occasionally K-rich (plotting in the shoshonitic field). Taking into account mineralogical and chemical pecularities of the PGM association occurring in the studied concentrate, it seems highly probable that its primary source should be an Alaskan-type intrusion.

---

Platingruppen Minerale aus dem Alluvium der Durance, Frankreich

Zusammenfassung Minerale der Platingruppe wurden im Zuge von Goldgewinnung im Alluvium der Durance in der Nähe von Peyrolles (Bouches-du-Rhône) entdeckt. Die PGM Körner (durchschnittliche Korngröße 130m) sind flach gepreßt (durchschnittliche Dicke 64m). Die PGM Konzentrate bestehen vorwiegend aus (Pt, Fe) Legierungen (92%); (Os, Ir, Ru) Legierungen (3,5%), sowie gediegen Gold und (Au, Cu, Ag) Legierungen (4,5%). Folgende Minerale wurden beobachtet:Isoferro-Platin, Fe-Platin, gediegen Osmium, gediegen Iridium, Iridosmium, Rutheniridosmium, Osmiridium, Ru-Osmium, Os-Ruthenium, Cuprorhodsit, Guanglinit, Shandit, Tetrauricuprit, gediegen Gold, Bornit, HeazIewoodit, (Pt, Pd)₂ Cu₃, Pt(Cu, Au), (Ni, Pt)Sn, (Cu, Fe), (Pd, Rh, Pt)_2+xS₂, (Pt, Pd)_4+xCu₂As_1–x.Isoferro-Platin enthält zahlreiche Einschlüsse von Legierungen, Sulfiden, Arseniden, Pd-Telluriden und teilweise devitrifzierte Silikatglaströpfchen. Die meisten nichtsili katischen Einschlüsse sind ebenfalls tröpfchenförmig. Dies weist darauf hin, daß sie in flüssigem Zustand eingeschlossen wurden.Cuprorhodsitkristalle (bis zu 20m) sind gemeinsam mit Bornit in Pt₃ Fe einge schlossen. Selten sind Pd- und Cu-Sulfide, sowie Pd-Telluride mit diesen vergesellschaftet. Bei den komplexen tröpfehenförmigen Arsenideinschlüssen im Isoferro-Platin handelt es sich um Pt-führenden Guanglinit und (Pt, Pd)_4+xCu₂ As_1–x. Gediegen Iridium zeigt Entmischung von Ir-führendem Isoferro-Platin und (Pt, Pd)₂Cu₃. Stellenweise wurden Konzentrationen von Sn (bis zu 3%) in den (Au, Cu) Legierungen beobachtet. Shandit und (Ni, Pt) Sn Einschlüsse kommen in (Au, Cu, Ag) Legierungen vor. Silikatische Glaseinschlüsse sind TiO₂-arm und manchmal K-reich (im Shoshonitfeld liegend).Auf Grund der mineralogischen und chemischen Eigenheiten der untersuchten PGM Konzentrate ist eine Intrusion des Alaska-Typs als primäre Quelle sehr wahrscheinlich.

---

---

With 4 Figures and 2 Plates