Investigation of current and future potential distribution of <Emphasis Type="Italic">Astragalus gossypinus</Emphasis> in Central Iran using species distribution modelling

The potential impact of climate change on Astragalus gossypinus in Central Iran based on grid map 2.5 arc min was analyzed. A stratified sampling was applied through a geographic information system to pick up 587 sample sites (prevalence 0.39). For each sampling site, the presence or absence of given species together with environmental variables was recorded. Two novel statistical techniques, logistic regression tree (LRT) and nonparametric multiplicative regression (NPMR), were used to examine environmental variables related to the current species distribution. Using these models, maps of current potential distribution and potential distribution for a climatic change scenario (2CO₂) were generated. Both statistical techniques produced strong and useful models, but NPMR identified a much smaller subset of relevant predictor variables. The model demonstrated that the occurrence of A. gossypinus is highly probable when the precipitation of the wettest month is between 30 and 50 mm and the mean temperature of the wettest quarter is between ?2 and +4 °C, but much lower outside this range. Under double-CO₂ climatic scenario, predicting a moister and slightly warmer climate in Central Iran, A. gossypinus is expected to move north-eastwards with a decreasing area of distribution.     

Observing upper troposphere–lower stratosphere climate with radio occultation data from the CHAMP satellite

High quality observations of the atmosphere are particularly required for monitoring global climate change. Radio occultation (RO) data, using Global Navigation Satellite System (GNSS) signals, are well suited for this challenge. The special climate utility of RO data arises from their long-term stability due to their self-calibrated nature. The German research satellite CHAllenging Minisatellite Payload for geoscientific research (CHAMP) continuously records RO profiles since August 2001 providing the first opportunity to create RO based climatologies for a multi-year period of more than 5 years. A period of missing CHAMP data from July 3, 2006 to August 8, 2006 can be bridged with RO data from the GRACE satellite (Gravity Recovery and Climate Experiment). We have built seasonal and zonal mean climatologies of atmospheric (dry) temperature, microwave refractivity, geopotential height and pressure with 10° latitudinal resolution. We show representative results with focus on dry temperatures and compare them with analysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF). Although we have available only about 150 CHAMP profiles per day (compared to millions of data entering the ECMWF analyses) the overall agreement between 8 and 30 km altitude is in general very good with systematic differences <0.5 K in most parts of the domain. Pronounced systematic differences (exceeding 2 K) in the tropical tropopause region and above Antarctica in southern winter can almost entirely be attributed to errors in the ECMWF analyses. Errors resulting from uneven sampling in space and time are a potential error source for single-satellite climatologies. The average CHAMP sampling error for seasonal zonal means is <0.2 K, higher values occur in restricted regions and time intervals which can be clearly identified by the sampling error estimation approach we introduced (which is based on ECMWF analysis fields). The total error of this new type of temperature climatologies is estimated to be <0.5 K below 30 km. The recently launched Taiwan/U.S. FORMOSAT-3/COSMIC constellation of 6 RO satellites started to provide thousands of RO profiles per day, but already now the single-satellite CHAMP RO climatologies improve upon modern operational climatologies in the upper troposphere–lower stratosphere and can act as absolute reference climatologies for validation of more bias-sensitive climate datasets and models.     

Biosilicium (BSi) in Sedimenten Mecklenburger Seen (Deutschland) und das Calciumcarbonat-Biosilicium-Verhältnis als Trophie- und Wasserstandsindikator Biogenic Silica (BSi) in Sediments of the Mecklenburgian Lake District (Germany) and the Calcite-Silica-Relation as Indicator for Trophy and Water Level

The BSi content has been investigated in the surface sediments of lakes of different trophic state in the Mecklenburgian Lake District. The BSi content differs between 1 to 1000 mg BSi/g dry matter. High values were found in deep eutrophic lakes. Litoral sediments and shallow eutrophic lakes have lower contents. BSi content was found to be correlated with lake morphometry, depth, trophic level, sediment composition and especially with calcite. With the CaCO₃/BSi-value, 3 groups of lakes can be characterized:

• CaCO₃/BSi = 0 oligotrophic and dystrophic lakes
• CaCO₃/BSi ≤ 10 mesotrophic and eutrophic deep lakes
• CaCO₃/BSi ≤ 10 eutrophic shallow lakes

The results from the recent sediments have been compared with those from older sediments. Using the CaCO₃/BSi-value, climatic change, trophic state, and sea level can be detected.     

Der Kohlendioxid-Gehalt und die Kalzitsättigung der Ilm, einschließlich einiger Vergleichsuntersuchungen im Thüringer Raum

The CO₂ content, air saturation and calcite equilibrium of the River Ilm and some of its tributaries were analysed. CO₂ content was measured by degasing the CO₂ from water. The CO₂ level is a very sensitive indicator for a low pollution in oxygen saturated waters. Clean running waters have a CO₂ content close to the air saturation of 0.1–0.3 mg C l⁻¹. Ground water and springs are rich in CO₂. Polluted waters are characterised by higher CO₂ contents, also organic pollution can result in high values of CO₂. Carbon dioxide concentration of streams and brooks is limited by re-aeration.

The headwater region (softwater) of the River Ilm is unsaturated, the hard water in the middle- and underflow is oversaturated. In summer and autumn high saturation could be found, but without autochthonous calcite precipitation like in hard water lakes.     

Effects of organic aerosol constituents on extinction and absorption coefficients and liquid water contents of fogs and clouds

We have speculated on the influence of organic material on extinction and absorption coefficients and liquid water content of fogs and of clouds immediately after their condensational stage. It results therefore, that the reduction of the speed of growth from fog to cloud droplets due to the presence of organic films largely reduces the properties mentioned. Compared to that their increase coming from the surface tension reduction due to organic material being dissolved or building up films is expected to be less effective.     

Humidity effects on gravitational settling and Brownian diffusion of atmospheric aerosol particles

The dependency on relative humidity of the settling velocity of aerosol particles in stagnant air and of the diffusion coefficient due to Brownian motion of aerosol particles was computed for six aerosol types and different particles sizes in dry state. The computations are based (1) on mean bulk densities of dry aerosol particles obtained from measurements or from the knowledge of the chemical composition of the particles, (2) on micro-balance measurements of the water uptake per unit mass of dry aerosol substance versus water activity at thermodynamic equilibrium, and (3) on measurements of the equilibrium water activity of aqueous sea salt solutions. The results show a significant dependence of the settling velocity and Brownian diffusion of aerosol particles on relative humidity and on the particle's chemical composition.Nomenclature A surface parameter of a particle - B surface parameter of a particle - c _L velocity of sound in moist air - C 1+Kn[A+Qexp(–B/Kn]=slip correction - D diffusion coefficient of a particle - D ₁ D(=1)=diffusion coefficient of a spherical particle - f P _w /P _we (T,P)=relative humidity (f=0 dry air,f=1 saturated air) - g acceleration due to gravity - g |g| - k 1.3804×10^–16 erg/°K=Boltzmann constant - Kn _L /r=Knudsen number of a particle - Kn _{0 0L} /r ₀=Knudsen number of a dry particle - m 4r ³/3=mass of a particle - m _L 4r ³ _L /3=mass of the moist air displaced by a particle - M mobility of a particle - M ₀ molar mass of dry air - M _w molar mass of water - Ma |u–u _L |/c _L =Mach number of the particles motion relative to the ambient air - n particle number per unit volume of air - P P ₀+P _w =pressure of the moist air - P ₀ partial pressure of the dry air - P _w partial pressure of the water vapour - P _we P _we (T,P)=equilibrium partial water vapour pressure over a plane surface of water saturated with air - Q surface parameter of a particle - r equivalent radius of a particle (radius of a sphere with the particles volume) - r ₀ equivalent radius of a particle in dry state - R 1+0.13Re ^0.85=inertia correction - R ₀ specific gas constant of dry air - R _w specific gas constant of water - Re 2r _L u–u _L / _L =Reynolds number of the particles motion relative to the ambient air - t time - T absolute temperature - u velocity of a particle - u (amount of the) settling velocity of a particle in stagnant air - u ₁ u(=1)=(amount of the) settling velocity of a spherical particle in stagnant air - u _L velocity of the ambient moist air (far enough from the particle where the flow pattern remains undistorted) - W drag coefficient of a particles equivalent sphere - empirical parameter in equation (3.1) - dynamic viscosity of a particles liquid cover - _L dynamic viscosity of moist air - _0L dynamic viscosity of dry air (at the same pressure and temperature like the moist air) - celsius temperature - dynamic shape factor of a particle (=1 for a sphere) - ₀ dynamic shape factor of a dry particle - _L mean free path of the molecules in moist air - _0L mean free path of the molecules in dry air (at the same pressure and temperature like the moist air) - _Po mean free path of the molecules in dry air at the pressureP ₀ of the dry air and the temperature given - factor of solid to liquid change-over (=1 for a solid particle) - mean bulk density of a particle - _L density of the moist air - _0L density of the dry air at the same pressure and temperature like the moist air - ₀ mean bulk density of a dry particle - ₀ mean diameter of the molecules of dry air - _w diameter of water molecules - relaxation time of a particle - gradient operation - 3.141593     

Statistical representation of generalized distribution data for float-sink coal-cleaning devices: Baum jigs,Batac jigs,Dynawhirlpools

In an earlier paper (1978), Gottfried presented a method for combining distribution data for float-sink coal-cleaning devices into a single generalized distribution curve which, for a given device and feed size, is independent of specific gravity of separation. A non-linear, exponential-type equation was utilized to represent the generalized distribution curve, along with the corresponding generalized probable error. Distribution data for six common coal-cleaning devices have previously been treated by this method.This paper is an extension of two previous studies (Gottfried, 1978, 1980). The method described above is applied to three different float-sink coal-cleaning devices: Baum jig (replacing previously reported results), Batac jig and Dynawhirlpool separator. Results for the Baum jig and Batac jig reflect a two-stage separation process, with a set of generalized distribution curves obtained for each stage and another set for the overall separation. Several different feed size fractions are given for each vessel.     

Isotopenvariationen des Stickstoffs humoser und bituminöser natürlicher organischer Substanzen

gd¹⁵N-values and nitrogen contents of a series of humic and bituminous organic sediments of different ranks were determined. The change of the isotopic abundance of nitrogen was investigated during heating in model experiments, using a gas flame coal.In the case of humic carbon coals the relative nitrogen contents vary from 0.8 to 1.4% and the δ¹⁵N-values from +3.5 to +6.3%. increasing from the brown coal to anthracite ranks. During the coalification process both the δ¹⁵N-values and the relative nitrogen contents do not vary continuously with the rank, but pass through maxima and minima. Model experiments using a gas flame coal show the same trend. Nitrogen with δ¹⁵N-values of +2.8 or ?7%. was released in pyrolysis experiments, applying a gas flame coal and a steam coal at temperatures of 650 and 1000°C, respectively.The investigated bitmuinous sediments yielded relative amounts of 0.1 to 0.8% with δ¹⁵N-values of + 4.2 to + 10.7%.The obtained results are discussed with respect to the elucidation of nitrogen genesis in natural gas deposits.     

Schollen und Schollenränder im Saarkarbon

Zusammenfassung Im bergbaulich erschlossenen Gebiet mit seinen guten Untertageaufschlüssen können verschiedene tektonische Baustile beobachtet werden, welche eine Gliederung in große Schollen zulassen. In den aufschlußärmeren Gebieten sind die Schollenränder nur mit Vorsicht festgelegt. Die Kennzeichen des Baustiles von der Scholle des Saarbrücker Hauptsattels werden jenen von den Nachbargebieten gegenübergestellt.     

LIBS analysis of geomaterials: Geochemical fingerprinting for the rapid analysis and discrimination of minerals

Laser-induced breakdown spectroscopy (LIBS) is a simple atomic emission spectroscopy technique capable of real-time, essentially non-destructive determination of the elemental composition of any substance (solid, liquid, or gas). LIBS, which is presently undergoing rapid research and development as a technology for geochemical analysis, has attractive potential as a field tool for rapid man-portable and/or stand-off chemical analysis. In LIBS, a pulsed laser beam is focused such that energy absorption produces a high-temperature microplasma at the sample surface resulting in the dissociation and ionization of small amounts of material, with both continuum and atomic/ionic emission generated by the plasma during cooling. A broadband spectrometer-detector is used to spectrally and temporally resolve the light from the plasma and record the intensity of elemental emission lines. Because the technique is simultaneously sensitive to all elements, a single laser shot can be used to track the spectral intensity of specific elements or record the broadband LIBS emission spectra, which are unique chemical ‘fingerprints’ of a material. In this study, a broad spectrum of geological materials was analyzed using a commercial bench-top LIBS system with broadband detection from ∼200 to 965 nm, with multiple single-shot spectra acquired. The subsequent use of statistical signal processing approaches to rapidly identify and classify samples highlights the potential of LIBS for ‘geochemical fingerprinting’ in a variety of geochemical, mineralogical, and environmental applications that would benefit from either real-time or in-field chemical analysis.