Simulation of cyclones using synthetic data

A number of sensitivity experiments have been conducted to investigate the influence of using synthetic data on cyclone forecasts by a global spectral model. Some well known vortices have been used and the generated wind and pressure profiles are compared. It is found that the Rankine vortex and Holland’s vortex show the best representation of cyclonic circulation. Hence these two vortices are used in the sensitivity studies to simulate two cyclones, one of May 1979 and the other of August 1979. For this purpose the FGGE level-III b data set, produced at ECM WF, UK is used. Synthetic temperature and humidity data are also introduced to make the cyclones more realistic. With the use of Holland’s vortex the system is found to move faster than with the Rankine vortex. Also, the tracks of the cyclones simulated with Rankine vortex are found to be on the left side of the observed track while that of Holland’s vortex is on the right side of the observed track. However, substantial filling up of the systems are noticed with introduction of diabatic initialization of the mass and velocity fields and the forecasts of both the vortices behave differently. It is suggested that proper selection of synthetic vortex, initialization scheme and resolution of the model are very important for better forecast of cyclones.     

Talc-chlorite-amphibole felses of the KTB pilot hole,Oberpfalz, Bavaria: Protolith characteristics and phase relationships

Summary The metagabbro-amphibolite sequences in the KTB pilot hole contain intercalations of talc-chlorite-amphibole felses (or hosbachites), which show transitional contacts to the adjacent metagabbros. The hosbachites are characterized by relics of a primary igneous texture and still contain igneous minerals like clinopyroxene, biotite and pseudomorphs after olivine, while brown Ca-amphibole was presumably formed in a late-magmatic stage. The geological, textural, mineralogical and geochemical evidence indicates that the hösbachites were derived from ultramafic cumulates, differentiated from a basaltic magma, either in the inner parts of dolerite sills or in small gabbro intrusions. A pervasive metamorphic overprint under medium-pressure, amphibolite-facies conditions which was accompanied by penetrative deformation led to assemblages with green Ca-amphibole ± anthophyllite ± cummingtonite ± tremolite/actinolite + clinochlore + talc + olivine + ilmenite ± Cr-bearing spinel + sulfides. Phase relationships are consistent with a prograde P-T path leading to the formation of anthophyllite from olivine + talc at peak metamorphic temperatures of 640–700°C, at assumed pressures of 8-10 kbar, similar to those derived from mineral assemblages in the adjacent metabasites and metasediments. High-pressure relics locally present in coronitic metagabbros and retrograded eclogites of the KTB pilot hole were not recognized in the hosbachites. A retrograde overprint under greenschist-facies conditions led to the total replacement of igneous or metamorphic olivine by aggregates of antigorite + magnetite, chloritization of biotite and the formation of late tremolite/ actinolite.

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Zusammenfassung Talk- Chlorit-Amphibol-Felse der KTB-Vorbohrung, Oberpfalz: Eduktcharakteristik und Phasenbeziehungen Die Metagabbro-Amphibolit-Folge in der KTB-Vorbohrung enthält Einschaltungen von Talk-Chlorit-Amphibol-Felsen (Hosbachite), die graduelle Übergänge zu den benachbarten Metagabbros aufweisen. Die Hosbachite sind durch Relikte von primären magmatischen Gefügen gekennzeichnet and führen noch magmatische Mineralrelikte wie Klinopyroxen, Biotit and Pseudomorphosen nach Olivin, während brauner CaAmphibol wahrscheinlich spdtmagmatisch gebildet wurde. Verbandsverhältnisse, Reliktgefüge und Reliktminerale sowie Haupt- und Spurenelement-Geochemie sprechen dafür, daß die Hosbachite auf ultramafische Kumulate zurückgehen, die aus einem basischen Magma differenziert wurden, and zwar entweder im Innern von doleritischen Lagergängen oder in kleinen Gabbro-Intrusionen.Eine durchgreifende metamorphe Überprägung unter Bedingungen der Mitteldruck Amphibolitfazies, die von einer penetrativen Deformation begleitet war, fuhrte zu Mineralparagenesen mit grünern Ca-Amphibol ± Anthophyllit ± Cummingtonit + Tremolit/Aktinolith + Klinochlor + Talk + Olivin + Ilmenit + Cr-haltigem Spinell + Sulfiden.Die Phasenbeziehungen weisen darauf hin, daß sich im Zuge eines prograden P-TPfades Anthophyllit aus der Paragenese Olivin + Talk bildete. Als P-T-Bedingungen beim Hbhepunkt der Metamorphose können Temperaturen von 640–700°C in einem angenommenen Druckbereich von 8-10 kbar abgeschätzt wurden, ähnlich wie sie auch aus den Mineralparagenesen in den angrenzenden Metabasiten and Metasedimenten der KTB-Vorbohrung ableitbar sind. Hochdruckrelikte, die gelegentlich in koronitischen Metagabbros and retrograd überprägten Eklogiten der KTB-Vorbohrung auftreten, wurden in den Hösbachiten nicht gefunden. Eine retrograde Überprägung unter grünschieferfaziellen Bedingungen führte zu einer vollständigen Verdrängung von magmatischem und metamorphem Olivin durch Aggregate von Antigorit + Magnetit, zur Chloritisierung von Biotit und zur Bildung einer späten Generation von Tremolit/ Aktinolith.

     

Application of limited fuzzy clusters to anomaly recognition in complex geological environments

In stream sediment and soil surveys, samples represent mixtures of components from different geological environments. Such mixed samples are misclassified when using conventional “hard” cluster methods. In fuzzy clustering, each sample is allowed to belong to several clusters. Similar to element concentrations, these cluster contributions can be displayed in contour maps (e.g. kriging maps). The amount of an element that is explained by the cluster contribution and element residuals can be calculated. The modified fuzzy clustering algorithm called “limited fuzzy clusters” used in this paper avoids negative residuals.Stream sediment data of Sierra de San Carlos, Tamaulipas, Mexico are used to demonstrate the possibilities of limited fuzzy clustering in geochemical exploration and mapping. From the different drainage systems, 681 stream sediment samples were taken and analyzed for 24 elements. A nineteen-element data set was used to calculate limited fuzzy clusters and element residuals. The contribution values for the clusters and element residuals are displayed in contour maps. All geological units were outlined by the cluster contributions. Extended anomalies are characterized by their own cluster. Small anomalies are clearly identified from the element residuals.     

Dendroclimatic studies on conifers from central Europe and Great Britain

Schweingruber, Fritz H., BrÄker, Otto U. & SchÄr, Ernst 1979 1201: Dendroclimatic studies on conifers from central Europe and Great Britain. Boreas, Vol. 8, pp. 427–452. Oslo. ISSN 0300–9483. The use of X-ray densitometry for measuring tree rings makes it possible to consider the relations between climate and tree rings in a new light. Investigations so far have shown that it is the maximum density of the annual rings that provides the most important and best climatological information. Comparisons between density sequences are possible when the tree-ring samples come from ecologically similar sites. Site characteristics are expressed by six different tree-ring parameters. Relations between the maximum densities of various species from different regions are revealed by calculating the percentage of agreement. The growth rate of cell walls in latewood of all coniferous species from cool humid regions is limited mainly by summer temperatures. In Scotland, where the climate is cool-oceanic and relatively stable, the cell walls grow from June to October. In the subalpine zone of the Alps and the Rocky Mountains near the timber line growth takes place mainly in August and September. Maximum density in trees of temperate sites is also primarily influenced by the summer temperature. Minimum density shows the relationship to the xerothermic site characteristics. On dry sites cambial activity and cell wall growth in latewood are mainly limited by precipitation during the growth period. Samples from the subalpine zones (1500–2200 m above sea level) between latitudes 45d? and 50d? North, i.e. those from the Western Carpathians, the Alps, and the Northern Appalachian Mountains, seem to form a unity. Samples from the oceanic region (20–600 m above sea level) between 52d? and 58d?N latitudes show a different and incoherent picture. Only the present low level density during 1950–1975 is evident at all sites investigated for the last 200 years. By cross-dating the annual tree-ring sequences of living trees with samples of timber taken from ancient houses a 700-year-long chronology has been developed for the Northern Prealps in Switzerland. This chronology shows the approximate annual and decennial temperature changes; the sensitivity curve shows the different climatic variability in temperature.     

Petroleum inclusions and residual oils: constraints for deciphering petroleum migration

The analysis of petroleum inclusions (PI) in parallel to residual oils (=bitumens) provided specific constraints for petroleum migration processes in the Prague Basin. Whereas organic geochemical information from bitumens is limited due to alteration, additional high quality information was obtained from C_1–14-range compounds inside crystals. This was obtained by the application of a closed system for the decrepitation and thermal extraction of PI with subsequent gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The resulting data not only show pristine live oils, gases, residual and precipitated bitumens and a broad variation of mixtures of the groups above, but also show that gas migration and fractionation processes played a major role in the Prague Basin.     

Proterozoic deformation of the East Saharan Craton in Southeast Libya, South Egypt and North Sudan

The basement areas in Southeast Libya, South Egypt and North Sudan, west of the Nile, between Gebel Uweinat and the Bayuda Desert, are part of an approximately 1000-km-wide, complexly folded, polymetamorphic zone with a regional N-NNE-NE-ENE trend of foliation and fold axis. Since this belt extends southwestward into the area of Zalingei in the southern Darfur block (West Sudan), it is named the Northern Zalingei fold zone. Sr and Nd isotopic studies suggest that this zone is older than Pan-African and further indicate that, apart from Archean rocks in the Gebel Uweinat area, this belt is of Early-Middle Proterozoic age. An Early-Middle Proterozoic three-stage deformational and anatectic event established the present-day fold and fault geometry in the western parts of this zone in the Gebel Uweinat—Gebel Kamil area. The Pan-African tectono-thermal episode was most effective in the eastern part of the belt, near the boundary with the Nubian Shield volcano-sedimentary-ophiolite-granitoid assemblages. It caused migmatization, granite emplacement, mylonitization and large-scale wrench faulting which was related to Late Proterozoic accretionary and collisional events of the Arabian-Nubian Shield with the margin of the East Saharan Craton.     

Transformation of phosphorus in the Elbe estuary

The distribution of dissolved and particle-bound phosphorus (P) was investigated in the Elbe estuary during March 1995. The forms of particulate P were studied with a sequential extraction technique. Organic P dominated particle-bound P in the outer reaches of the estuary (52%), decreased to a minimum of 21% in the turbidity zone, and increased to 33% further upstream. Fe-bound P was the second most important P species in the outer reaches (27%) and dominated in the turbidity zone (up to 57%) and upstream of the turbidity zone (up to 48%). The P:Fe ratio increased with decreasing salinity, from 0.11 in the outer reaches to about 0.22 at zero salinity. Dissolved inorganic P release from reverine suspended matter was about two to three times larger than release, from marine suspended matter and was dominated by release of Fe-bound P. Dissolved inorganic P release from marine and from riverine organic matter were of equal importance. Because marine suspended matter dominates in the estuary, this suggests riverine organic matter is remineralized much faster than marine organic matter. This is in line with the refractory nature of marine organic matter (no phytoplankton bloom) and the easily degradable character of the riverine suspended matter (phytoplankton bloom) in the Elbe estuary during March 1995.     

Low temperature spectral studies of Mn3+-bearing andalusite and epidote type minerals in the range 30000–5000 cm−1

Polarized absorption spectra of natural piemontite (Ca_1.802Mn ²⁺_0.178 Mg_0.025) (Mn ³⁺_0.829 Fe ³⁺_0.346 Al_1.825) [(Si_2.992Al_0.008) O₁₂OH], viridine (Al_1.945Mn ³⁺_0.033 Fe ³⁺_0.063 Mg_0.003) [O|Si_0.970 O₄], and kanonaite (Al_1.291Mn ³⁺_0.682 Fe ³⁺_0.019 ) [O|Si_1.006 O₄] were measured at 295 and ca. 100 K. For piemontite, lowering the temperature resulted in a sharpening of broad bands in the 10 000–25 000 cm⁻¹ region supporting their assignment to single ion Mn³⁺ in M3 non-centrosymmetric sites.

Alternatively, in kanonaite, temperature behaviour pointed to a slightly stronger influence of vibronic coupling on strong bands near 16 000 and 22 000 cm⁻¹, which supported an interpretation of Mn³⁺ in nearly centrosymmetric M1 sites. Measurements at ca. 100 K show pronounced fine structure in the viridine spectra which is attributed to Fe³⁺. The ɛ values for Mn³⁺ spin-allowed bands in the three minerals lie in the range 18 to 227 [1·g-atom⁻¹·cm⁻¹].

For the same band and polarisation, ɛ values in Mn³⁺-bearing andalusite-type minerals viridine and kanonaite are the same, which indicates an absence of strong magnetic coupling effects between Mn³⁺ ions in the andalusite type structure down to ca. 100 K.

In silicates, the high ɛ values for Mn³⁺ spin-allowed bands, in comparison to those obtained for Fe²⁺ spin-allowed bands from sites of “similar distortion”, is attributed to a higher degree of covalency in the Mn³⁺-O bonds compared to the Fe²⁺-O bonds, as a result of the higher valence state of manganese.

     

Land Reserves in Southern Sumatra/Indonesia and their potentialities for agricultural utilization

In contrast to overpopulated Java the neighbouring island of Sumatra still provides huge unused land reserves. However, by far not all of these reserves can be regarded as real agricultural potentials, e.g. for resettlement projects. Especially the poor soils often prove an agricultural handicap. Besides soil fertility the existing vegetation has to be conidered. Thus, for example, the so called alang alang grass savannas in general show better potentialities than forest areas, while most of the swamps prove rather unsuitable for agricultural development.With regard to the already existing landuse types the cultivation of perennial bush- and tree crops, for instance rubber, seems to be best suited for further expansions. An expansion of annual food crops would be feasible too, however only be applying heavy capital inputs; here wet rice cultivation would be more appropiate than the permanent cultivation of annual upland crops like cassava, maize, etc. The traditional shifting cultivation does not serve as an alternative any longer. Animal breeding will have its difficulties, with the exception of certain highland areas.Taking into account all ecological, social, and economic reservations it is concluded that, in spite of considerable restrictions, a good part of the land reserves in southern Sumatra could still be opened and used successfully for agricultural purposes.The present paper is based mainly on the results of the Sumatra Regional Planning Study (SRPS 1974) performed in the four southern provinces of Sumatra and financed by the governments of Indonesia and the Federal Republic of Germany besides the World Bank. Directed by H. Kötter and K. H. Junghans, an interdisciplinary team of members of the Bonn university (Fed. Rep. of Germany) and of several Indonesian institutions performed research work, the author being responsible for investigations into regional land-use. Additional contributions of importance to this study were made by H. Buchholz, M. Budianto, K. H. Junghans, P. Meimberg, R. Moertomo, Parmadi, A. Rieser, T.S. Salim and I. Satoto.Supplementary research performed in late 1977 an early 1979 was financed by the Deutsche Forschungsgemeinschaft (German Research Society). We are greatly indebted to this institution for its generous assistance.