Native IMAGE Overview

Native IMAGE Overview - Dr. Hank Lehrer and Jan Bingen

Native IMAGE First Year Report: Goals Achieved - Third Tribal Forum - August 2004 - Sandiego, CA

Native IMAGE First Year Report: Goals Achieved - Third Tribal Forum - August 2004 - Sandiego, CA Jan Bingen (Little Priest Tribal College); Karisa Vlasek & Hank Lehrer (University of Nebraska at Omaha

Nebraska NativeGEM (Geospatial Extension Model)

The UNO Aviation Monograph Series, UNOAI Report 04-3, Nebraska NativeGEM (Geospatial Extension Model) - February 2004 - UNO Aviation Institute, University of Nebraska at Omaha

On the accuracy of the SGP4 to predict stellar occultation events using ENVISAT/GOMOS data and recommendations for the ALTIUS mission

In preparation for the operations of the ALTIUS mission, research is carried out to assess the accuracy of the SGP4 orbital propagator in predicting stellar occultation events. The quantification of the accuracy and its consequent improvement will enable reliable measurement planning and, therefore, maximize the number of measurements. To this end, predictions are made for the timing of occultations for the GOMOS instrument on-board the ENVISAT, which are then compared to actual occultation occurrences. It is found that the error is substantial but follows a trend that can be interpolated. This enables devising a method for highly accurate predictions given a sufficient number of data points. Statistically significant results for the accuracy of the propagator and a calibration method are presented. Recommendations for a measurement planning procedure of ALTIUS are formulated

Development, Production and Evaluation of Aerosol Climate Data Records from European Satellite Observations (Aerosol_cci)

Producing a global and comprehensive description of atmospheric aerosols requires integration of ground-based, airborne, satellite and model datasets. Due to its complexity, aerosol monitoring requires the use of several data records with complementary information content. This paper describes the lessons learned while developing and qualifying algorithms to generate aerosol Climate Data Records (CDR) within the European Space Agency (ESA) Aerosol_cci project. An iterative algorithm development and evaluation cycle involving core users is applied. It begins with the application-specific refinement of user requirements, leading to algorithm development, dataset processing and independent validation followed by user evaluation. This cycle is demonstrated for a CDR of total Aerosol Optical Depth (AOD) from two subsequent dual-view radiometers. Specific aspects of its applicability to other aerosol algorithms are illustrated with four complementary aerosol datasets. An important element in the development of aerosol CDRs is the inclusion of several algorithms evaluating the same data to benefit from various solutions to the ill-determined retrieval problem. The iterative approach has produced a 17-year AOD CDR, a 10-year stratospheric extinction profile CDR and a 35-year Absorbing Aerosol Index record. Further evolution cycles have been initiated for complementary datasets to provide insight into aerosol properties (i.e., dust aerosol, aerosol absorption).Peer reviewe

Redistribution of rare earth elements, thorium, and uranium over accessory minerals in the course of amphibolite to granulite facies metamorphism: The role of apatite and monazite in orthogneisses from southwestern Norway

The amphibolite to granulite facies transition has been studied in a high-K calc-alkaline, hornblende-biotite, K-feldspar megacrystic augen gneiss series from the Rogaland-Vest-Agder (RogVA) sector of the Sveconorwegian province (southwest Norway). Hornblende begins to break down mainly to clinopyroxene at the Cpx-in isograd and biotite mainly to orthopyroxene at the Opx-in isograd (abbreviations for minerals following Kretz, 1983). The magmatic accessory mineral association comprises titanite and allanite, which begin to break down before the Cpx-in isograd. Titanite is preserved as relict inclusions in other minerals at higher grade. Monazite and thorite formed in the breakdown of allanite. Monazite abundance reaches a maximum between the Cpx-in and Opx-in isograds. The middle and heavy rare earth element (M-HREEs, except Eu) content of apatite steeply increases with increasing metamorphic grade and is directly correlated to the decrease of the modal abundances of titanite, hornblende, and biotite. The U contents of apatite are low and do not increase with metamorphic grade. The light rare earth elements (LREEs) and Th content of apatite are not correlated to the breakdown of allanite around the Cpx-in isograd but increase around the Opx-in isograd. A simplified equation is proposed for monazite crystallisation in the vicinity of the Cpx-in isograd that accounts for the allanite, titanite, and hornblende breakdowns and the M-HREE substitution in apatite: 3 (M-HREE)2O3 + 3 (LREE)2O3 + 2 Ca5(PO4)3(F,OH) + 6 SiO2 ⇔ in hornblende and titanite in allanite apatite quartz 6 (LREE)PO4 + 2 Ca2(M-HREE)3(SiO4)3(F,OH) + 6 CaO. monazite lessingite in apatite in plagioclase At the Opx-in isograd, the increase of LREEs and Th content of apatite results either from the breakdown of some monazite: 3 (LREE)PO4 + 3 SiO2 + 7 CaO + (F2,H2O) ⇔ Ca5(PO4)3(F,OH) + Ca2(LREE)3(SiO4)3(F,OH), monazite quartz in plagioclase fluid apatite lessingite in apatite or the breakdown of the remaining allanite: 3 (LREE)2O3 + 6 SiO2 + 4 CaO + (F2,H2O) ⇔ 2 Ca2(LREE)3(SiO4)3(F,OH). in allanite quartz in plagiocluse fluid lessingite in apatite The release of fluorine from the breakdown of biotite at the Opx-in isograd may increase apatite stability relatively to monazite in the granulite facies. When compared to amphibolite facies, the granulite facies augen gneisses do not show any U or Th depletion. This means that changes in the accessory mineral associations and the simultaneous breakdown of hydrous minerals at the amphibolite-granulite facies transition do not inevitably result in depleted granulite facies rocks but rather to an isochemical element redistribution. The coexistence of small amounts of metamorphic monazite and of relict inclusions of titanite in upper amphibolite facies augen gneisses suggests that (high-K) calc-alkaline orthogneisses are a suitable material to date (with the U-Pb method) prograde path of amphibolite facies regional metamorphism on monazite and the cooling path on titanite.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Evolution of feldspars at the amphibolite-granulite-facies transition in augen gneisses (SW Norway): geochemistry and Sr isotopes

The Sveconorwegian Augen Orthogneisses of Rogaland - Vest-Agder (SW Norway) were emplaced as amphibole- and biotite-bearing granodiorites at 1040 Ma (concordant Rb/Sr and zircon U/Pb ages). They underwent prograde metamorphism which increased from lower amphibolite-facies in the eastern zone to granulite-facies in the western zone, close to the Rogaland anorthosite complex. K-feldspar megacrysts initially crystallised as phenocrysts and were chemically equilibrated during metamorphism, as shown by the flat Ba concentration profiles and the increase of the anorthite content from An1.1 in the amphibolitefacies to An2.6 in the granulite-facies. This increase of the An content suggests an increase in metamorphic temperature. The REE content of the megacrysts is related to the associated accessory minerals which depend upon the metamorphic grade: sphene + allanite + apatite + zircon and rarely thorite in amphibolite-facies, and apatite + zircon + monazite ± thorite in lower amphibolite-and granulite-facies. Amphibole and biotite inclusions in megacrysts were also equilibrated during metamorphism. Groundmass K-feldspar and plagioclase experienced late-metamorphic changes during uplift. An internal Rb/Sr mineral isochron (plagioclase, apatite, K-feldspar) defines an age of 870 Ma, which represents the closure of the Rb/Sr isotopic system in minerals of the augen gneisses. This age also represents a K-feldspar cooling age in regionally distributed augen gneiss samples. The K-feldspar cooling age appears to be similar to or slightly older than the biotite cooling age. © 1990 Springer-Verlag.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Geochemistry of the Lyngdal hyperites (S.W. Norway): comparison with the monzonorites associated with the Rogaland anorthosite complex

The Lyngdal hyperites (LYHY) crop out as two small, post-tectonic intrusions of gabbro-noritic to monzonoritic composition, at the extreme South of Norway. They display subophitic textures with plagioclase laths (An40 to An58), orthopyroxene (En56 to En62), clinopyroxene (Wo47.5En39Fs13.5), ilmenite, magnetite and interstitial myrmekite fringes, K-feldspar, quartz, apatite and biotite. The SiO2 content is very constant (50-53%), but K2O ranges from 1% to 1.6% in differentiated facies. REE patterns are smooth [( La Yb)n = 6]. The hyperites define an Rb Sr isochron of 910 ± 82 Ma (2σ), with an initial ratio of 0.7054. ε{lunate}Nd is slightly positive (0 to +2) and average lead isotopic initial ratios are 17.45 [(206Pb204Pb)i] and 15.51 [(207Pb204Pb)i]. The LYHY represent magmatic liquids that have not fractionated large amounts of plagioclase. They are quite comparable to the rocks of the monzonoritic series that occur in the nearby Rogaland anorthosite complex. (1) The plagioclases have the same composition; plagioclase phenocrysts are locally present. (2) They display enrichments in TiO2, P2O5 and K2O. (3) They have comparable REE patterns. (4) The isotopic data show that the monzonorites and the LYHY derive from the same isotopic reservoir. The LYHY nevertheless differ from the monzonorites by their high-Al content (Al2O3 = 18.5%) and their lower FeOtot content ( FeOtot FeOtot + MgO = 0.62). The geochemical and isotopic diversity of the monzonoritic magmatism, including the LYHY, implies that each occurrence represents a distinct magma batch generated from a distinct source. The LYHY could tentatively be interpreted as a Fe-poor (Mg-rich) end-member of the monzonoritic magmatism occurring to the East of the anorthosite complex. © 1990.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

K-rich calc-alkaline augen gneisses of Grenvillian age in S.W. Norway: mingling of mantle-derived and crustal components

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Avis sur l’évaluation de la mise en œuvre du contrat de gestion d’Actiris 2013-2017 et recommandations en vue de l’élaboration du contrat de gestion 2017-2021

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