Deuteron whistlers in the outer ionosphere

Summary Upgoing and downgoing deuteron whistlers were found on VLF records made by Interkosmos 5, 14 and 19 satellites even at heights below 1000 km. To account for them, a slight admixture ofD ⁺ ions has been introduced into the ionospheric plasma model with the usual content of only three ion speciesH ⁺,He ⁺ andO ⁺. Relations derived for the calculation of characteristic frequencies in a five-component plasma (e,H ⁺,D ⁺,He ⁺,O ⁺) are given as well as the values of characteristic frequencies calculated on this basis. The observed features of upgoing and downgoing deuteron whistlers could be explained by the calculation results, and it is also possible to formulate some conclusions for the purposes of plasma diagnostics.

---

mu um, anmau a ma u u, u a a nmua m 5, 14 u 19 a ma ¶rt;a 1000 . u u a ¶rt;a ¶rt; u na ¶rt;au uH ⁺,He ⁺,O ⁺ aa nuD ⁺ u. m mm ua nma ¶rt;a ¶rt; aamumuu amm ¶rt;a ¶rt;u na. uu aamumuu amm nuu um a¶rt;a mu ¶rt;mu um. a m ¶rt; unam aamumuu ¶rt;mu um ¶rt; u¶rt;au naam na.

     

Measurements of stratospheric NO2 profiles using a gas correlation radiometer in the solar occultation mode

Compact two-channel IR radiometers for solar occultation experiments have been constructed in order to measure concentration profiles of stratospheric trace gases. The instruments can be used as filter-or gas correlation-type radiometers depending on the trace gas under investigation. Within the LIMS correlative measurement program, balloon flights were performed with a payload of up to four of these two-channel radiometers. From the gas correlation-type measurements, profiles of the trace gas NO₂ are inferred for the altitude region between about 20 km and the balloon float level. The data evaluation also includes a comprehensive analysis of the error sources and their effect on the accuracy of the NO₂ profiles. The derived profiles are compared among themselves and are assessed against the observations of other authors by accounting for the diurnal, latitudinal and seasonal changes of NO₂. As a by-product of our measurements, the mean absorption of the O₂ collision-induced band at 6.4 m was determined within the range of the interference filter used and compared with calculations based on known absorption coefficients.     

Mathematische Modellierung der Komplexbildung von Metallen und ihre Nutzung bei der Interpretation physikochemischer Prozesse in natürlichen Wässern

A mathematical model is presented for the calculation of the concentrations or activities of complex compounds in the thermodynamic equilibrium state. Ten central atoms and ten ligands which form 400 complexes at the most can be included in the model. Complex stability constants, total concentrations of the central atoms and ligands, temperature and pH-value constitute input quantities. Activity and temperature dependence of the stability constants are covered by respective subprogrammes. The model is tested by the migration rate of iron(II) within a sand-filled column with a cation-exchange capacity of 1 mval/100 g solid matter: If there is an excess of sulphate, the iron(II)-breakthrough will be considerably earlier, the same holding for the EDTA-complex, whereas by means of EDTA the iron(II) bonded to the soil by ion exchange can be redissolved. In the batch experiment also the rate of oxidation of iron(II) is dependent on the degree of complexing. The model can be extended for dissolving, precipitation and redox processes.     

Evaluation of the ALADIN 3D-VAR with observations of the MAP campaign

Summary The aim of this work is to evaluate several 3D-VAR assimilation cycles in the limited area model ALADIN, in comparison with the dynamical adaptation of the global model (ARPEGE) analysis, and with a focus on the precipitation forecasts. We perform a detailed evaluation for a specific, well documented, test case: Intensive observing period 14 of the Mesoscale Alpine Programme (MAP) field campaign, which is well described through various MAP data. The meteorological situation was of high interest, with triggering of convection both over the Alps and over the sea, therefore it has been chosen as the framework of our case study. There are clear benefits in favour of the 3D-VAR assimilation cycles over the first hours of forecast thanks to the observations and to the preservation of small-scale features. These improvements are further enhanced with a large-scale update step added to the 3D-VAR analysis. Innovative data are used, such as relative humidity pseudo-profiles which are processed data generated from cloud classification. They bring an important information which can redesign the frontal areas. When they are used jointly with the conventional observations in the 3D-VAR, they also lead to an improvement of the precipitation scores.     

Test of a solar streamline analysis on terrestrial wind data

Terrestrial wind data are used to test a technique for obtaining solar streamline patterns from line-of-sight velocity measurements. The method of analysis and its limitations are discussed. The major features of the reconstructed terrestrial streamline pattern agree satisfactorily with those of the actual wind field.     

Correcting Radial Velocities for Long-Term Magnetic Activity Variations

We study stars in the Lick planetary survey for correlations between simultaneous measurements of high-precision radial velocities vr and magnetic activity (as measured in an SIR emission index from Ca ii lambda8662). We find significant correlations in approximately 30% of the stars. After removing linear trends between SIR and vr, we find that the dispersion in vr in these stars is decreased by an average of 17%, or approximately 45% of the dispersion above the measurement noise. F stars and less active stars with variable Ca ii H and K lines are the most successfully corrected. The magnitude of the slope of the SIR versus vr relations increases proportional to vsini and (excepting M dwarfs) tends to decrease with decreasing Teff. We argue that the main cause of these effects is modification of the mean line bisector shape brought on by long-term, magnetic activity-induced changes in the surface brightness and convective patterns. The correlations can be used to partially correct vr data for the effects of long-term activity variations, potentially permitting study of planets around some (higher mass) younger stars and planets producing smaller stellar reflex velocities.     

Sedimentology of a Late Quaternary lacustrine record from the south-eastern Carpathian Basin

The Upper Pleistocene geoarchives in the south-eastern Carpathian Basin are represented predominantly by loess–palaeosol records. In 2015, a 10 m sediment core composed of clay-rich lacustrine sediments was recovered by vibracoring a dry lake basin located between the Vršac Mountains (Serbia) and the Banat Sands in the south-eastern Carpathian Basin; a location relevant for placing regional archaeological results in a palaeoenvironmental context. Here, we present results from geoelectrical prospection and a lithostratigraphic interpretation of this sequence supported by a detailed granulometric study supplemented by ostracod analysis. An age model based on luminescence dating is discussed against sedimentological proxy data and its implication for palaeoenvironmental change. The cores show a stratigraphy of lighter ochre-coloured and darker greyish sediment, related to the deposition of clay and silt trapped in an aquatic environment. Geophysical measurements show ~20 m thick lacustrine sediments. The grain-size distributions including the variability in fine clay are indicative of a lacustrine environment. Fine particles were brought into the depositional environments by aquatic input and settled from suspension; also, direct dust input is constrained by grain-size results. Riverine input and aeolian dust input interplayed at the locality.