Spin rate estimation of sounding rockets using GPS wind-up

Carrier phase wind-up is a well-known effect that arises from the relative rotation between a transmitting and receiving antenna. In GPS measurements at L1 frequency, this effect translates into an error of 19.029 cm per full relative rotation of antennas. Since this effect is independent of the satellite elevation for pure rotation about the antenna boresight axis, it is usually absorbed by the clock estimation in navigation algorithms. Therefore, the impact of wind-up is usually neglected for applications that do not require accuracies to the cm level like RTK. However, in receiving platforms with high rotation rate, the accumulated wind-up value can be important and actually be larger than receiver noise or even ionospheric variations. Therefore, in such scenarios, the wind-up contribution can be isolated and used as a source of information to compute the spin rate of such platforms using an appropriate combination of GPS observables. This work shows some results of a coarse, yet simple, approach to monitor the rotation angle and spin-rate of spin stabilized sounding rockets flown by DLR.     

Water balance in the playa-lakes of an arid environment,Monegros, NE Spain

The playa-lakes of the Monegros desert in north-east Spain are saline wetlands in an arid environment, a rare phenomenon in Europe. These extremely valuable habitats are threatened by changes associated with agricultural expansion and incorporation of new irrigated areas. An understanding of the present hydrologic regime will enable changes to be identified, particularly those brought about by flooding and pollution caused by irrigation surplus. This study sets out to show the results of applying a daily water balance in three selected playa-lakes. The balance was in two parts and consisted of: (1) the average balance for all the endorheic basin using the BALAN_11 program, and (2) the water balance in some playa-lakes, applying discharge flows obtained from the previous balance. The resulting volumes of water were converted to water depths and contrasted with reference volumes taken from field and Landsat images. The model was calibrated by applying various hypotheses of function which enabled the results to be adjusted. The proposed balance is an acceptable reproduction of field water measurements during this period, and underlines the consistency of the conceptual model. The methodology used is appropriate for understanding the playa-lakes function and for monitoring them for conservation purposes.     

Giant ancient landslide in the Alma water gap (Crimean Mountains,Ukraine): notes to the predisposition,structure, and chronology

Large-scale ancient landslides of the area of more than 5 km² and volume exceeding 200 × 10⁶ m³ are characteristic features of the valleys incised in the northern periphery of the Crimean Mountains (Ukraine). The largely affected area is located in the outermost cuesta range of the Crimean Mountains which consists of rigid Sarmatian limestones overlying weak Middle Miocene and Upper Palaeogene deposits. A giant landslide arose in the Alma water gap as a reflection of several coincident preparatory factors such as suitable bedrock stratification, smectite-rich bedrock exposed to swelling activity, presence of faults parallel to the valley trend, and river capture event which preceded the landslide event. The occurrence of such ancient megaslides is particularly interesting in the area which is characterized by low precipitation (<500 mm/year) and weak contemporary seismicity. It probably reflects a more dynamic environment in humid phases of the Holocene; however, seismic triggering along the Mesozoic suture zone cannot be rejected. Compressional features such as gravitational folds in the central and distal parts of the landslide, which probably correlate with the whole landslide genesis or its significant reactivation, arose, according to the radiocarbon dating, during the Holocene climatic optimum in the Atlantic period. The slope deformation has been relatively quiescent since that time, except minor historic reactivization which took place in the frontal part of the landslide. We suppose that the studied landslide could be classified as a transitional type of slope deformation with some signs of spreading and translational block slides.     

Provenance of the Bosnian Flysch

Sandwiched between the Adriatic Carbonate Platform and the Dinaride Ophiolite Zone, the Bosnian Flysch forms a c. 3000 m thick, intensely folded stack of Upper Jurassic to Cretaceous mixed carbonate and siliciclastic sediments in the Dinarides. New petrographic, heavy mineral, zircon U/Pb and fission-track data as well as biostratigraphic evidence allow us to reconstruct the palaeogeology of the source areas of the Bosnian Flysch basin in late Mesozoic times. Middle Jurassic intraoceanic subduction of the Neotethys was shortly followed by exhumation of the overriding oceanic plate. Trench sedimentation was controlled by a dual sediment supply from the sub-ophiolitic high-grade metamorphic soles and from the distal continental margin of the Adriatic plate. Following obduction onto Adria, from the Jurassic–Cretaceous transition onwards a vast clastic wedge (Vranduk Formation) was developed in front of the leading edge, fed by continental basement units of Adria that experienced Early Cretaceous synsedimentary cooling, by the overlying ophiolitic thrust sheets and by redeposited elements of coeval Urgonian facies reefs grown on the thrust wedge complex. Following mid-Cretaceous deformation and thermal overprint of the Vranduk Formation, the depozone migrated further towards SW and received increasing amounts of redeposited carbonate detritus released from the Adriatic Carbonate Platform margin (Ugar Formation). Subordinate siliciclastic source components indicate changing source rocks on the upper plate, with ophiolites becoming subordinate. The zone of the continental basement previously affected by the Late Jurassic–Early Cretaceous thermal imprint has been removed; instead, the basement mostly supplied detritus with a wide range of pre-Jurassic cooling ages. However, a c. 80 Ma, largely synsedimentary cooling event is also recorded by the Ugar Formation, that contrasts the predominantly Early Cretaceous cooling of the Adriatic basement and suggests, at least locally, a fast exhumation.     

Hierarchical decomposition of variance with applications in environmental mapping based on satellite images

A quadtree-based image segmentation procedure (HQ) is presented to map complex environmental conditions. It applies a hierarchical nested analysis of variance within the framework of multiresolution wavelet approximation. The procedure leads to an optimal solution for determining mapping units based on spatial variability with constraints on the arrangement and shape of the units. Linkages to geostatisiics are pointed out, but the HQ decomposition algorithm does not require any homogeneity criteria. The computer implementation can be parameterized by either the number of required mapping units or the maximum within-unit variance, or it can provide a spectrum of significances of nested ANOVA. The detailed mathematical background and methodology is illustrated by a salt-affected grassland mapping study (Hortobágy, Hungary), where heterogeneous environmental characteristics have been sampled and predicted based on remotely sensed images using these principles.     

Red dust rain within the Spanish Mediterranean area

Dust rain belongs to the climatological conditions of the Iberian Peninsula's Mediterranean seaboard. Traditionally known as muddy' or bloody rains, red dust rain has become a topical issue as a result of more frequent rainfall of this kind in recent years. In spite of the difficulties that studying this phenomenon involves, owing to the lack of systematically kept records at meteorological observatories, details are provided of the high frequency of such phenomena within the Spanish Mediterranean area, using records from other phenological sources. The study analyzes the chemical composition of red dust rain and the atmospheric factors giving rise to such phenomena. Whether there is a relationship betwen the higher frequency of dust rain and possible changes in global atmospheric circulation is as yet unclear.     

Energy balance of simple elastodynamic sources

Complete relations are derived for energy and energy flux of elastic waves generated by an isotropic and double-couple source in a perfectly elastic, homogeneous, isotropic, and unbounded medium. In the energy balance of elastodynamic sources near-field waves play an essential role, transforming static energy into wave energy, andvice versa. For explosive and dislocation sources, the sources surface radiates a positive wave energy that is partially distributed to the medium transforming into static energy. For implosive and antidislocation sources, the source surface generates elastic waves, but it does not necessarily imply that it also radiates a positive wave energy. The energy transported by waves can originate in gradual transformation of the static-to-wave energy during propagation of waves through a stressed medium.On leave from Geophysical Institute, Czech Academy of Sciences, Boní II/1401, 41 31, Praha 4 Czech Republic     

Redefining active volcanoes: a discussion

The analysis of the current definitions of active volcanoes indicates that they are empirical, conventional, inaccurate, nongeological, and arbitrarily constraining. Redefinition is therefore needed. One possible approach is to refine the current empirical definitions. A statistically reasonable and practical redefinition using a geologically based time convention-Holocene or 10000 years-is suggested. A set of time conditions according to volcano typology-i.e. 1000; 10000 and 100000 years for high-frequency basaltic shields, andesitic-dacitic composite volcanoes and low-frequency large silicic calderas, respectively-as further refinement of the empirical definition is also envisaged. Devising a phenomenological definition as a theoretical approach is another possibility, but in practice extant diagnostic means are still unsatisfactory to discriminate accurately between dormant and extinct volcanoes. As a consequence of the redefinition, a classification of volcanoes according to their eruptive status is proposed. Redefinition of active volcanoes might increase accuracy in the usage of basic terms in volcanology and influence volcanic hazard assessment and risk mitigation projects.