Comparison of Global-Scale and Mesoscale Modelling of Vertical Profiles in the Martian Atmosphere: How Does Model Resolution Impact Predictions of Conditions at Mission Landing Sites?

Detailed modelling of the Martian atmosphere is completed for every spacecraft designed to land on the planet’s surface. This provides the most complete picture of the environment that the descending module will be entering and travelling through, and facilitates planning of the Entry, Descent and Landing (EDL) phase of the mission. The selected resolution of an atmospheric model can impact the results of the experiments performed. The complexities of atmospheric modelling also require models of different scales to best represent the behaviour of different scale atmospheric phenomena. Comparisons between multiple model results and in situ data are crucial for improving future environmental predictions for missions landing on Mars. This work describes how changes in model scale and resolution (horizontal and vertical) can impact experimental results, using as a case study the selected landing site of the European Space Agency (ESA) Schiaparelli module. Schiaparelli was part of ESA’s ExoMars 2016 mission; the module descended through the Martian atmosphere on 19th October 2016. Experiments were completed that encompassed the period of Schiaparelli’s descent, using both a global-scale and a mesoscale model. The global model used in this work is the UK version of the LMD (Laboratoire de Météorologie Dynamique) Mars Glob-al Circulation Model (“the MGCM”), a 3D multi-level spectral model of the Martian atmosphere up to an altitude of ~100 km [1]. The mesoscale model used in this work is the LMD Martian Mesoscale Model (MMM) [2]; in these experiments an altitude of ~50 km was modelled in the mesoscale. Multiple resolution experiments were completed using the MGCM; results range from a ‘low’ resolution ~5° latitude x ~5° longitude (a resolution typically used for Martian climate modelling) to a ‘high’ resolution ~1° lat x ~1° lon. The vertical dimension is modelled using a set number of vertical layers; in these experiments the number of vertical layers selected was between 23 and 100. Experiments were run for a simulated year, starting from initial conditions based upon prior atmospheric observations, thus providing an independent prediction of conditions through the period of this case study. The MMM experiments were com-pleted in a set of nested resolutions, ranging from the outer, lowest resolution results at 63 km x 63 km, to the inner, highest resolution results at 7 km x 7 km. MMM experiments were completed using 60 vertical layers. Previous comparisons of global-scale and meso-scale modelling have focused on areas containing small-scale topographical variation that is not present in the global scale models. This work considers the relatively flat topography of the Schiaparelli site – a location that is more representative of the majority of historical Martian landing sites than areas that contain severe, small-scale topographical variation. Initial analysis has focused on constructing vertical profiles from the model output at both experimental scales, following preliminary information on the descent trajectory of the Schiaparelli module. An example comparison of atmospheric profiles constructed from MGCM results at different model resolutions. The plot displays atmospheric temperature obtained from experiments completed at different vertical resolutions: 23 and 100 vertical levels. There is a good match between the results, with a root mean square deviation (RMSD) of 9.83 K be-tween the results for the full height of the profiles; the RMSD reduces to 2.05 K when considering only the lowest ~10 km of the profiles (approximately one scale height). A comparison of vertical atmospheric temperature profiles from MGCM and MMM results. While the trend in the results is similar, the results differ by ~10 K between the models through most of the profile, down to a height of ~3 km above the surface. Between 50 and 3 km above the surface the RMSD of the profiles is 9.79 K; below 3 km (down to the lowest MGCM model lay-er) the match is closer, with an RMSD of 2.59 K. Further comparisons have been completed between the MGCM and MMM results, such as wind speed and direction, including consideration of the wider topographical and atmospheric context of Schiaparelli’s landing site and EDL period. These results show that, for the region considered within this case study, changing the horizontal or verti-cal resolution used in MGCM experiments does not greatly impact the results obtained. Similarly, the MMM results do not vary more than ~4 K with chang-ing horizontal resolution. In both cases, lower resolu-tions results (which are quicker and less computationally expensive to complete) are a good approximation of higher resolution results. Additionally, the similarity of the trends seen in the results from the different scale models suggests that global-scale model results are a reasonable approximation for mesoscale model results, for a number of potential landing locations on Mars. The module successfully transmitted some data that was captured during its descent, primarily from engineering sensors; this data includes the module's trajectory and attitude during the mission’s EDL phase. The ExoMars AMELIA (Atmospheric Mars Entry and Landing Investigations and Analysis) team aim to use the data returned by Schiaparelli during descent, combined with dynamic modelling of the module's motion, to reconstruct atmospheric profiles of density, pressure, temperature and wind speed [3]. Upon the release of the Schiaparelli data, the results from both the MGCM and MMM experiments will be compared with the data, supporting the work of the AMELIA team. References: [1] Forget et al. (1999) JGR, 104, E10. [2] Spiga et al. (2009) JGR, 114, E2. [3] Ferri et al. (2012) 9th International Planetary Probe Workshop

«WALLSCAPES»: EVOLUTION OF THE MARANO HILL FORTIFICATIONS (CUPRA MARITTIMA - ITALY) THROUGH MATERIALITY AND PERCEPTIONS

The article analyses the walls of Marano, a small town in the back-coastal hills of the Marche region, between Fermo and Ascoli. Written sources related to the development of the settlement and data derived from the walls that still stand have been analysed. Moreover, a short insight into the development of the settlement in relation to the walls is presented through the results acquired during the archaeological excavation undertaken in 2018. Finally, the article explains how the perception of the walls has changed over time in relation to the Marano geopolitical context and the rediscovery of the Roman period settlement

Da Cupra a Marano. Insediamenti e abitati, traslazioni e transizioni

L’intervento intende illustrare i risultati della prima campagna di ricerche svolte dall’Università Ca’ Foscari Venezia nel territorio di Cupra Marittima (AP). Le ricerche sono state condotte lungo la valle del torrente Menocchia, appena a N dell’attuale centro costiero, e nel borgo di Marano, posto sui primi rilievi collinari. Il progetto si pone l’obiettivo generale di studiare la parabola dell’insediamento cuprense tra la tarda antichità e il medioevo. La valle del torrente Menocchia è stata oggetto di sondaggi geoarcheologici realizzati tramite trivella manuale. Sono stati indagati i primi cinque metri di stratificazione su un’area di circa 25 ettari. Gli interventi sono stati finalizzati alla prima esplorazione della zona in cui si colloca tradizionalmente il porto romano e, più generalmente, alla definizione, seppure parziale, delle trasformazioni geomorfologiche che hanno coinvolto il centro originario di Cupra a partire dalla tarda antichità. Nel borgo di Marano, invece, è stata effettuata una prima valutazione del potenziale informativo degli edifici ancora in elevato e sono stati realizzati il rilievo e la lettura stratigrafica dei prospetti dell’edificio che attualmente ospita il Museo Archeologico Comunale del territorio di Cupra Marittima, appartenente al primo nucleo medievale dell’abitato. Questa prima fase di ricerche ha permesso di gettare le basi per lo studio delle tecniche costruttive e lo sviluppo urbano del borgo

The diversity and evolution of cell cycle regulation in alpha-proteobacteria: a comparative genomic analysis

<p>Abstract</p> <p>Background</p> <p>In the bacterium <it>Caulobacter crescentus</it>, CtrA coordinates DNA replication, cell division, and polar morphogenesis and is considered the cell cycle master regulator. CtrA activity varies during cell cycle progression and is modulated by phosphorylation, proteolysis and transcriptional control. In a phosphorylated state, CtrA binds specific DNA sequences, regulates the expression of genes involved in cell cycle progression and silences the origin of replication. Although the circuitry regulating CtrA is known in molecular detail in <it>Caulobacter</it>, its conservation and functionality in the other alpha-proteobacteria are still poorly understood.</p> <p>Results</p> <p>Orthologs of <it>Caulobacter </it>factors involved in the regulation of CtrA were systematically scanned in genomes of alpha-proteobacteria. In particular, orthologous genes of the <it>divL-cckA-chpT-ctrA </it>phosphorelay, the <it>divJ</it>-<it>pleC</it>-<it>divK </it>two-component system, the <it>cpdR</it>-<it>rcdA</it>-<it>clpPX </it>proteolysis system, the methyltransferase <it>ccrM </it>and transcriptional regulators <it>dnaA </it>and <it>gcrA </it>were identified in representative genomes of alpha-proteobacteria. CtrA, DnaA and GcrA binding sites and CcrM putative methylation sites were predicted in promoter regions of all these factors and functions controlled by CtrA in all alphas were predicted.</p> <p>Conclusions</p> <p>The regulatory cell cycle architecture was identified in all representative alpha-proteobacteria, revealing a high diversification of circuits but also a conservation of logical features. An evolutionary model was proposed where ancient alphas already possessed all modules found in <it>Caulobacter </it>arranged in a variety of connections. Two schemes appeared to evolve: a complex circuit in <it>Caulobacterales </it>and <it>Rhizobiales </it>and a simpler one found in <it>Rhodobacterales</it>.</p

Il lago ottocentesco di Villa Savoia (Roma)

Nel settore nordorientale dell'area urbana di Roma si trova il parco di Villa Ada, intensamente frequentato dalla cittadinanza per le sue bellezze naturalistiche ed architettoniche. La sovrapposizione di interventi antropici nel corso della storia antica e recente della Città Eterna ha determinato, in un peculiare contesto geologico e geomorfologico, una complessa evoluzione del territorio; allo stato attuale l'area verde richiede attenzione sia per la protezione e conservazione dei beni ambientali e culturali, sia per il monitoraggio dei fenomeni di dissesto e la tutela della pubblica incolumità. Il principale fattore di rischio è rappresentato infatti dalla elevata probabilità di formazione di sinkholes antropogenici, connessi allo sviluppo di cavità nel sottosuolo; rispetto a ciò vari Enti pubblici e privati hanno da tempo avviato ricerche, a partire dal censimento e mappatura della rete caveale ipogea e delle voragini conclamate o incipienti che sono largamente diffuse all'interno del comprensorio [...]

Mapping multiple gas/odor sources in an uncontrolled indoor environment using a Bayesian occupancy grid mapping based method

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Robotics and Autonomous Systems 59 (2011): 988–1000, doi:10.1016/j.robot.2011.06.007.In this paper we address the problem of autonomously localizing multiple gas/odor sources in an indoor environment without a strong airflow. To do this, a robot iteratively creates an occupancy grid map. The produced map shows the probability each discrete cell contains a source. Our approach is based on a recent adaptation [15] to traditional Bayesian occupancy grid mapping for chemical source localization problems. The approach is less sensitive, in the considered scenario, to the choice of the algorithm parameters. We present experimental results with a robot in an indoor uncontrolled corridor in the presence of different ejecting sources proving the method is able to build reliable maps quickly (5.5 minutes in a 6 m x 2.1 m area) and in real time

POLARIX: a pathfinder mission of X-ray polarimetry

Since the birth of X-ray astronomy, spectral, spatial and timing observation improved dramatically, procuring a wealth of information on the majority of the classes of the celestial sources. Polarimetry, instead, remained basically unprobed. X-ray polarimetry promises to provide additional information procuring two new observable quantities, the degree and the angle of polarization. POLARIX is a mission dedicated to X-ray polarimetry. It exploits the polarimetric response of a Gas Pixel Detector, combined with position sensitivity, that, at the focus of a telescope, results in a huge increase of sensitivity. Three Gas Pixel Detectors are coupled with three X-ray optics which are the heritage of JET-X mission. POLARIX will measure time resolved X-ray polarization with an angular resolution of about 20 arcsec in a field of view of 15 arcmin $\times$ 15 arcmin and with an energy resolution of 20 % at 6 keV. The Minimum Detectable Polarization is 12 % for a source having a flux of 1 mCrab and 10^5 s of observing time. The satellite will be placed in an equatorial orbit of 505 km of altitude by a Vega launcher.The telemetry down-link station will be Malindi. The pointing of POLARIX satellite will be gyroless and it will perform a double pointing during the earth occultation of one source, so maximizing the scientific return. POLARIX data are for 75 % open to the community while 25 % + SVP (Science Verification Phase, 1 month of operation) is dedicated to a core program activity open to the contribution of associated scientists. The planned duration of the mission is one year plus three months of commissioning and SVP, suitable to perform most of the basic science within the reach of this instrument.Comment: 42 pages, 28 figure