A heat flow and physical properties package for the surface of Mercury

European Space Agencies fifth cornerstone mission BepiColombo includes a ‘Surface Element’ to land a scientific payload on the surface of Mercury. The current strawman payload includes a heat flow and physical properties package (HP³), focussing on key thermal and mechanical properties of the near-surface material (down to a depth of 2–5 m) and the measurement of heat flow from Mercury's interior, an important constraining parameter for models of the planet's interior and evolution. We present here an overview of the HP³ experiment package and its possible accommodation in a self-inserting ‘mole’ device. A mole is considered to be the most appropriate deployment method for HP³, at least in the currently-assumed case of an airbag-assisted soft landing architecture for the Mercury Surface Element.     

GALACSI – The ground layer adaptive optics system for MUSE

MUSE, the Multi-Unit Spectroscopic Explorer, is an adaptive optics (AO)-assisted Integral Field Spectrograph, currently in the Preliminary Design Phase as a second generation instrument for the VLT. MUSE will feature two modes, each with an associated AO mode. The first mode is the wide field mode, mainly aiming at the study of high redshift galaxies. For this mode, the AO system has to deliver an improvement of at least a factor of two over the full 1′ × 1′ field of view. The second mode, the narrow field mode, aims at the high-resolution spectroscopy of nearby extended objects, for example, galaxies and globular clusters. For this mode, the AO system will have to deliver near-diffraction limited performance over a small field of view. In this paper, we discuss the trade-offs in the current design of GALACSI – the MUSE AO system – and illustrate with a number of simulations the expected performance in the wide- and narrow field modes.     

On the application of combined geoelectric weighted inversion in environmental exploration

Geophysical surveying methods are of great importance in environmental exploration. Inversion-based data processing methods are applied for the determination of geometrical and physical parameters of the target model. The use of this geoelectric inversion method is advantageous in environmental research where highly reliable information with large spatial resolution is required. The 2D combined geoelectric inversion (CGI) method performs more accurate parameter estimation than conventional 1D single inversion methods by efficiently decreasing the number of unknowns of the inverse problem (single means that data sets of individual vertical electric sounding stations are inverted separately). The quality improvement in parameter space is demonstrated by comparing the traditional 1D inversion procedure with a 2D series expansion-based inversion technique. The CGI method was further developed by weighting individual direct current geoelectric data sets automatically in order to improve inversion results. The new algorithm was named combined geoelectric weighted inversion, which extracts the solution by a special weighted least squares technique. It is shown that the new inversion methodology is applicable to resolve near-surface structures such as rapidly varying layer boundaries, laterally inhomogeneous formations and pinch-outs.     

Debris flow impact assessment caused by 14 April 2012 rainfall along the Al-Hada Highway,Kingdom of Saudi Arabia using high-resolution satellite imagery

The Al-Hada highway that descends towards the west of the city of At-Taif is a major connecting highway in the western part of the Kingdom of Saudi Arabia. It is one of the series of descending roads connecting the holy city of Makkah and the city of Jeddah with the city of At-Taif and the cities farther south along the escarpment. The length of the Al-Hada highways is about 22 km. The Al-Hada highway has been historically exposed to landslides and other geohazards since the day it was opened to public some 60 years ago. The road has been reconstructed and many slope instabilities have been remediated and the road has been expanded to two lanes in each direction. Heavy rainfalls occurred on the 14th of April 2012 in the province of At-Taif, causing huge debris flows in two places along the Al-Hada highway. As a result of that, these debris flows closed all four lanes of the highway for 2 weeks in order to remove the debris. The current research deals with mapping of all debris flows along Al-Hada highway and determining their volumes and their impact on the road. Finally, suitable solutions have been suggested to address these critical sites to minimize and/or avoid the debris flow hazards in the future.     

Earth Fissures in Wadi Najran,Kingdom of Saudi Arabia

The formation of earth fissures due to groundwater depletion has been reported in many places in North America, Europe, and Asia. Najran Basin is in the southern part of the Kingdom of Saudi Arabia, and agricultural activities and other groundwater uses have caused significant groundwater depletion there. The basin recently experienced a sudden appearance of numerous earth fissures. An interdisciplinary study consisting of an evaluation of land-use changes, and hydrological, hydrogeological, and geophysical investigations was conducted to determine the reason for the formation of the earth fissures. The hydrological analysis strongly revealed that the groundwater level is decreasing with time. Groundwater depletion would lead to the accumulation of subsurface stress, causing soil hydro-consolidation which creates the ideal condition for the formation of earth fissures. Electrical resistivity, data indicated that there are anomalies in the profiles, which are most probably due to the presence of subsurface topography, another key factor for the formation of the earth fissures.     

Extended Sediment Quality Rating for Trace Elements in Urban Waters – Case Study Klinke,Germany

The European Water Framework Directive (WFD) commits European Union member states to achieving good ecological status in all water bodies by 2015. For sediments the definition of good chemical status is based on numerical sediment quality guidelines. The aqua regia fraction is thus used for the evaluation of heavy metal concentrations in sediments. The chemical constituents in sediments responsible for mobility and toxicity are not considered generally. This article presents the combining of the sequential BCR procedure, for determining the chemical species of relevant elements, with the geoaccumulation index principle a numerical classification method for sediment quality guidelines. Using the BCR method it can be demonstrated that changes in element speciation can lead to more highly mobile species of trace elements which may affect the hazardous potential of sediments despite the “good chemical status” classification for aqua regia digestions. The Klinke stream is an urban surface water body located in Magdeburg, the state capital of Saxony‐Anhalt, Germany. Using this stream as an example it is shown that this additional information helps to describe the dynamics and discharge of the trace elements Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Mo, Pd, Cd, Sb, Ba, Pb, Bi, and U into the Elbe River from urban water bodies.