Slope Orientation Research Articles

Índices topográficos aplicados à modelagem agrícola e ambiental

Índices topográficos (IT) obtidos computacionalmente a partir do modelo numérico de elevação do terreno (MNE) têm sido incorporados em algoritmos computacionais aplicados na simulação de processos hidrológicos, erosivos e de transporte de poluentes. Por meio desses índices, zonas de acúmulo de umidade em uma bacia hidrográfica, por exemplo, podem ser previstas espacialmente através de IT, que levam em consideração efeitos de orientação de drenagem e declividade do terreno. Este trabalho tem como propósito o de apresentar uma revisão bibliográfica sobre esse tema e de demonstrar a aplicabilidade desses índices por meio de alguns exemplos, aplicada à modelagem agrícola e ambiental.

Spatial distribution of chloride and nitrate within an unsaturated dune sand of a cold-arid desert: Implications for paleoenvironmental records

Abstract Based on chloride mass balance approach, we used two tracers (Cl − and NO 3 − ) to study the interstitial water in four profiles of an unsaturated dune sand. The aim was to reconstruct the recharge history and use this to infer the long-term related climate changes and vegetation transitions in a cold-arid desert region of northwestern China. The estimated recharge rate of 0.21 to 0.59 mm year − 1 represented approximately 0.2 to 0.7% of the annual precipitation in the western Badain Jaran desert. The orientation of a megadune's slopes appeared to greatly affect recharge variability. Below the near-surface peaks, the total cumulative NO 3 –N inventories ranged from 61 to 121 kg ha − 1 . The near-surface peaks in NO 3 –N, with larger NO 3 –N/Cl − molar ratios, reflected active modern N-fixation by cyanobacteria, and the nitrate enrichment deeper in the unsaturated moisture zone indicated drier periods with less vegetation, limited nitrate fixation, or a combination of the two.

Livestock Feed Management and Fodder Consumption Pattern in Remote and Inaccessible Villages of Central Himalaya, India

It is well-nigh known that the most common sources of feed and fodder in the Central Himalayan tracts are mainly of five categories: (1) the forests; (2) common pastures and grazing lands; (3) private tree-leafy fodder; (4) field bunds and risers; (5) crop residues supplied from cropped areas. Forest, pastures and grazing commons are village property, while the rest are private owned. Barn yard millets, barley and wild sorghum are also used as concentrate feed. Green weeds are, of course, a good green fodder source, especially in irrigated tracts. The tradition of cultivated fodder is nearly absent in mountains. Shrubs, wild grasses and other herbs supply major parts of fodder supplies. The supply of grass varies with altitude, orientation of hill slopes, wind precipitation and relief of terrain. It may be obtained from leaves, twigs, shrubs, creepers, roots, bark, fruits, pods, seeds etc., other than the general grass. Intermix of all fodder grasses and leaves are believed to yield greater nutrition. Bhimal (Grewia optiva) kharik (Celtis australis) are free from tannin, which makes them best for digestibility. This paper attempts to analyse the fodder-feeding pattern in sample villages of Central Himalaya, especially in context of remotely placed far-flung tracts of Uttarakhand.

Detection of Magnetic Field Intensity Slope Direction by Homing Pigeons in a “Virtual Magnetic Map” during a Novel Spatial Conditioning Task

Event Abstract Back to Event Detection of Magnetic Field Intensity Slope Direction by Homing Pigeons in a “Virtual Magnetic Map” during a Novel Spatial Conditioning Task Cordula Mora1* and Vern P. Bingman1 1 Bowling Green State Universiy, Psychology, United States Homing pigeons are able to return to their loft from distant and unfamiliar places and have become one of the main model species to study avian navigation. It is well established that homing pigeons possess a magnetic compass to determine direction during homing, but whether or not homing pigeons also possess a magnetic map for position determination during navigation has been the subject of intense speculation for several decades. Sensitivity to changes in magnetic field intensity has long been considered a prerequisite for any position determining system utilizing the Earth’s magnetic field. Whilst it has been demonstrated that pigeons can discriminate the presence and absence of a magnetic field intensity anomaly in a conditioning task, it is not known whether pigeons are able to utilize magnetic intensity cues to solve spatial orientation tasks. In this study, six pigeons, walking inside a circular arena whilst attached to a horizontal tracker arm, were required to solve a spatial conditioning task based on magnetic intensity cues to obtain a food reward. The pigeons were required to detect the direction of a magnetic field intensity slope in a novel “virtual magnetic map” environment. Not only were the pigeons able to identify the orientation of the intensity slope, which was associated with the most rapid change in magnetic intensity, but they were able to discriminate movement upward versus downward on the slope as indicated by increasing versus decreasing intensity values. During sessions for which the ophthalmic branch of the trigeminal nerve was impaired by local anesthesia, the mean discrimination performance fell to chance level (50%), as it did during control sessions, for which the magnetic coils were turned off. Our results therefore demonstrate for the first time that pigeons are able to detect and respond to changes in magnetic field intensity in a spatial orientation task, adding magnetic sensitivity to a growing list of sensory cues that can be utilized during spatial cognition. Furthermore, such ability fulfills the basic requirements for use of magnetic intensity cues for position determination in a navigational map as previously proposed by the Walker (1998) model and provides additional evidence for the involvement of the trigeminal system in avian magntoreception. Ongoing research will involve sectioning of the trigeminal nerve to confirm transmission of magnetic information via this pathway as well as hippocampal lesions to investigate the brain regions associated with the processing of magnetic map information. Keywords: Cognition, Homing, Homing Pigeon, Magnetoreception, navigation, Sensory Perception Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for Participant Symposium) Topic: Orientation and Navigation Citation: Mora C and Bingman VP (2012). Detection of Magnetic Field Intensity Slope Direction by Homing Pigeons in a “Virtual Magnetic Map” during a Novel Spatial Conditioning Task. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00132 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Dr. Cordula Mora, Bowling Green State Universiy, Psychology, Bowling Green, Ohio, United States, cmora@bgsu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Cordula Mora Vern P Bingman Google Cordula Mora Vern P Bingman Google Scholar Cordula Mora Vern P Bingman PubMed Cordula Mora Vern P Bingman Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Landslide susceptibility assessment in Limbe (SW Cameroon): A field calibrated seed cell and information value method

The dissected volcanic terrains around Limbe, SW Cameroon are frequently affected by small scale but destructive landslides. In this study, a raster-based data driven method involving seed cells is used to build a landslide susceptibility model for the Limbe area. Factors considered to be potential controls of slope failure within this area include slope gradient, rock type, distance from roads, slope orientation, mean annual precipitation, soil type, land cover type, stream density and distance from stream. 63 small to very small translational and rotational landslide scars were identified through extensive field work. Landslide data is randomly divided into a training (75%) and validation set (25%) and seed cells are generated by creating 25 m buffer zones around the head scarp of each scar. The quantitative relationship between landslide seed cells and the above-mentioned factors is established by a data driven approach to obtain weighted factor classes. Summing weighted factor layers, a continuous scale of susceptibility indices is obtained and reclassified into 5 susceptibility classes. Seed cells obtained from the validation data set were used to evaluate the quality of several models involving different controlling factors. Our preferred model combines the weight of 6 factors (i.e. slope gradient, land cover, mean annual precipitation, stream density, proximity to roads and slope orientation). 78% of the validation seed cells are located within the high to very high susceptibility class, which occupy 16.9% of the study area. The obtained susceptibility map is combined with the outline of urban areas and key infrastructures to evaluate zones that are vulnerable to the impact of future slope failures. Such an approach will assist civil protection and urban planning efforts in SW Cameroon. Language: en

Periglacial features in Patriot Hills, Ellsworth Mountains, Antarctica

This work describes periglacial features identified at Patriot Hills, at the southernmost part of Ellsworth Mountains, Antarctica, during the 2008/2009 Brazilian Antarctic Expedition, and discusses their morphogenetic environment. Identified periglacial features were classified into: (a) rock glacier-like landform; (b) slightly creeping debris-mantled slopes; (c) steep debris-mantled slopes; and (d) rock falls. Results obtained from sediment sample analysis suggest activity and passive movement of a rock glacier-like landform, albeit minimal. Wind seems to play an important role in Patriot Hills local geomorphology. Periglacial features such as slightly creeping debris-mantled slope appear to have preferred slope orientation. They are commonly found onto slopes where the katabatic wind flows down. Slopewash and groundwater movement processes may be limited or non-existent since most snow disappears through sublimation

The importance of piled wood debris on the distribution of bird-dispersed plants in burned and logged Mediterranean pine forests

Plant dispersal and colonisation are important processes in vegetation recovery after fire and, for several species, depend on the presence of frugivorous avian seed dispersers. In burned and salvage-logged Mediterranean pine forests, the occurrence of disperser birds is enhanced by the presence of wood debris piles built as erosion barriers, which become seed dispersal foci. We hypothesised that the distribution of bird-dispersed plants after fire could be determined by the presence of wood piles. We analysed the differences in species richness and overall cover of bird-dispersed plants, as well as the cover of the most common species, within piles and outside them. We also tested if micro-environmental conditions (slope orientation and pile size) might influence plant occurrence. We found more species and overall cover within piles, when located on southern and south-eastern slopes, than outside them. Moreover, taller piles showed higher values of bird-dispersed plant cover and richness. Therefore, wood piles may provide the necessary conditions for bird-dispersed plant recruitment in dry burned areas. To our knowledge, this is the first reported man-made structure that clearly benefits the recovery of bird-dispersed plants in burned areas, and suggests that piles may be a useful restoration measure when logging Mediterranean burned forests.

Inter-ramp and bench design of open-pit mines: the Portage pit case study

Using a case study, this paper presents an integrated methodology for assessing structural slope stability at the inter-ramp and bench levels. Robust algorithms have been developed and implemented to compute, at inter-ramp and bench levels, slope orientations and slope stability using input data compatible with a commercially available mine-design software tool database structure. Multi-criteria stability analyses were performed based on various design criteria. Susceptibility maps were produced enabling the identification of zones of concern in the designed pit. The obtained results suggest that inter-ramp angles do not present instability concerns over the entire pit surface. At bench levels, potential instability zones were identified within two structural domains totalling 6% of the total pit surface.

Inter-ramp and bench design of open-pit mines : the Portage pit case study

Using a case study, this paper presents an integrated methodology for assessing structural slope stability at the in- ter-ramp and bench levels. Robust algorithms have been developed and implemented to compute, at inter-ramp and bench levels, slope orientations and slope stability using input data compatible with a commercially available mine-design software tool database structure. Multi-criteria stability analyses were performed based on various design criteria. Susceptibility maps were produced enabling the identification of zones of concern in the designed pit. The obtained results suggest that inter- ramp angles do not present instability concerns over the entire pit surface. At bench levels, potential instability zones were identified within two structural domains totalling 6% of the total pit surface.

Structural evolution of the Dayman dome metamorphic core complex, eastern Papua New Guinea

Research Article| November 01, 2011 Structural evolution of the Dayman dome metamorphic core complex, eastern Papua New Guinea Nathan R. Daczko; Nathan R. Daczko † 1Geochemical Evolution and Metallogeny of Continents Australian Research Council (GEMOC ARC) National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Sydney, Australia †E-mail: nathan.daczko@mq.edu.au Search for other works by this author on: GSW Google Scholar Peter Caffi; Peter Caffi 1Geochemical Evolution and Metallogeny of Continents Australian Research Council (GEMOC ARC) National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Sydney, Australia Search for other works by this author on: GSW Google Scholar Paul Mann Paul Mann § 2Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78758-4445, USA §Current address: Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204-5007; pmann@uh.edu Search for other works by this author on: GSW Google Scholar GSA Bulletin (2011) 123 (11-12): 2335–2351. https://doi.org/10.1130/B30326.1 Article history received: 07 May 2010 rev-recd: 13 Oct 2010 accepted: 21 Oct 2010 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Nathan R. Daczko, Peter Caffi, Paul Mann; Structural evolution of the Dayman dome metamorphic core complex, eastern Papua New Guinea. GSA Bulletin 2011;; 123 (11-12): 2335–2351. doi: https://doi.org/10.1130/B30326.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A shallow-dipping ductile mylonitic shear zone and concordant brittle detachment fault (Mai'iu fault) together make up the dominant geological structure that controls the orientation of dip slopes on the flanks of Mount Dayman, eastern Papuan Peninsula, Papua New Guinea. The dip slopes dip in all directions from the peak of Mount Dayman and form a domed landform that is much less dissected by streams compared to the adjacent Mount Suckling domed landform. The orientation of megacorrugations on the domed surface of Mount Dayman (footwall) is consistent with NNE-directed transport of the hanging-wall block, which is composed of low-grade undifferentiated volcanic and sedimentary rocks and minor ultramafic rocks. Though previously documented as a thrust surface, the geometry and style of structures and map relations presented in this study indicate an extensional origin for the domed mylonitic foliation (S1) and mineral elongation lineation (L1). The field relationships are consistent with the domed landform comprising the core of a metamorphic core complex. Observations of dominantly NNE-trending regional lineaments in aerial photography and Shuttle Radar Topography Mission (SRTM) data correlate with detailed field analysis of mineral elongation lineations (L1) in the main metamorphic core complex–bounding shear zone. Field relationships show a crosscutting sequence of structures that includes: (1) ductile S2 folia with ESE-plunging blue sodic-calcic amphibole mineral elongation lineations; (2) narrow, steeply dipping ductile D2 shear zones; and (3) semibrittle to brittle fault zones. S-C′ fabrics, asymmetric strain shadows around porphyroclasts, and fault drag indicate a top-down-to-the-NNE sense of shear for most structures. Kinematic vorticity analysis of the highest-grade ductile deformation indicates a kinematic vorticity number (Wk) between 0.34 and 0.56, suggesting general shear for the early stage of deformation (D1). The NNE-directed lineaments and L1 mineral elongation lineations are consistent with the Australia-Woodlark Eulerian pole for periods between the early Pliocene (3.6 Ma) and Pleistocene (0.52 Ma). This observation is consistent with ca. 3.3 Ma granite and monzonite intrusions that cut the mylonitic fabrics and limit the age of the mylonitic fabrics to older than 3.3 Ma on Mount Suckling. A SE-dipping sedimentary sequence (Gwoira Conglomerate) characterizes part of the hanging wall of the metamorphic core complex. Petrography of the clasts within the sedimentary rocks indicates that metabasite rocks were the dominant source. The unit is in fault contact with the metabasite footwall across prehnite-bearing D3 brittle fault zones. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Structural evolution of the Dayman dome metamorphic core complex, eastern Papua New Guinea

Research Article| November 01, 2011 Structural evolution of the Dayman dome metamorphic core complex, eastern Papua New Guinea Nathan R. Daczko; Nathan R. Daczko † 1Geochemical Evolution and Metallogeny of Continents Australian Research Council (GEMOC ARC) National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Sydney, Australia †E-mail: nathan.daczko@mq.edu.au Search for other works by this author on: GSW Google Scholar Peter Caffi; Peter Caffi 1Geochemical Evolution and Metallogeny of Continents Australian Research Council (GEMOC ARC) National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Sydney, Australia Search for other works by this author on: GSW Google Scholar Paul Mann Paul Mann § 2Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78758-4445, USA §Current address: Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204-5007; pmann@uh.edu Search for other works by this author on: GSW Google Scholar GSA Bulletin (2011) 123 (11-12): 2335–2351. https://doi.org/10.1130/B30326.1 Article history received: 07 May 2010 rev-recd: 13 Oct 2010 accepted: 21 Oct 2010 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Nathan R. Daczko, Peter Caffi, Paul Mann; Structural evolution of the Dayman dome metamorphic core complex, eastern Papua New Guinea. GSA Bulletin 2011;; 123 (11-12): 2335–2351. doi: https://doi.org/10.1130/B30326.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A shallow-dipping ductile mylonitic shear zone and concordant brittle detachment fault (Mai'iu fault) together make up the dominant geological structure that controls the orientation of dip slopes on the flanks of Mount Dayman, eastern Papuan Peninsula, Papua New Guinea. The dip slopes dip in all directions from the peak of Mount Dayman and form a domed landform that is much less dissected by streams compared to the adjacent Mount Suckling domed landform. The orientation of megacorrugations on the domed surface of Mount Dayman (footwall) is consistent with NNE-directed transport of the hanging-wall block, which is composed of low-grade undifferentiated volcanic and sedimentary rocks and minor ultramafic rocks. Though previously documented as a thrust surface, the geometry and style of structures and map relations presented in this study indicate an extensional origin for the domed mylonitic foliation (S1) and mineral elongation lineation (L1). The field relationships are consistent with the domed landform comprising the core of a metamorphic core complex. Observations of dominantly NNE-trending regional lineaments in aerial photography and Shuttle Radar Topography Mission (SRTM) data correlate with detailed field analysis of mineral elongation lineations (L1) in the main metamorphic core complex–bounding shear zone. Field relationships show a crosscutting sequence of structures that includes: (1) ductile S2 folia with ESE-plunging blue sodic-calcic amphibole mineral elongation lineations; (2) narrow, steeply dipping ductile D2 shear zones; and (3) semibrittle to brittle fault zones. S-C′ fabrics, asymmetric strain shadows around porphyroclasts, and fault drag indicate a top-down-to-the-NNE sense of shear for most structures. Kinematic vorticity analysis of the highest-grade ductile deformation indicates a kinematic vorticity number (Wk) between 0.34 and 0.56, suggesting general shear for the early stage of deformation (D1). The NNE-directed lineaments and L1 mineral elongation lineations are consistent with the Australia-Woodlark Eulerian pole for periods between the early Pliocene (3.6 Ma) and Pleistocene (0.52 Ma). This observation is consistent with ca. 3.3 Ma granite and monzonite intrusions that cut the mylonitic fabrics and limit the age of the mylonitic fabrics to older than 3.3 Ma on Mount Suckling. A SE-dipping sedimentary sequence (Gwoira Conglomerate) characterizes part of the hanging wall of the metamorphic core complex. Petrography of the clasts within the sedimentary rocks indicates that metabasite rocks were the dominant source. The unit is in fault contact with the metabasite footwall across prehnite-bearing D3 brittle fault zones. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Ulteri considerazioni sulla correzione topografica nei rilievi gravimelrici geominerari

In t h e present paper we are dealing with residual erroroccurring when considering surfaces of cylindrical compartment in gravimetrictopographic correction, horizontal.I t is shown how residual error variations in a compartment dependon the average level, average slope and slope o r i e n t a t i o n of topographicsurface in t h e compartment.The residual error of a zone or a n ensemble of zones may be positiveor negative according to s t a t i s t i c a l distribution of slope orientations. Asa n example, the results of a gravimetric survey are related.Rapid methods to value t h e residual error and to eliminate it in somecases are suggested.

Water relations and hydraulic architecture of two Patagonian steppe shrubs: Effect of slope orientation and microclimate

On a local scale, topography influences microclimate, vegetation structure and the morpho-physiological attributes of plants. We studied the effects of microclimatic differences between NE- and SW-facing slopes on the water relations and hydraulic properties of two dominant shrubs of the Patagonian steppe in Argentina ( Retanilla patagonica and Colliguaja integerrima). The NE-facing slope had higher irradiance and air saturation deficits and lower soil water availability and wind speed than the SW-facing slope. Predawn and midday Ψ L and osmotic potentials were significantly lower in shrubs on the NE-facing slope. Osmotic adjustment and more elastic cell walls helped the plants to cope with a more xeric environment on NE-facing slope. Higher water deficits on NE-facing slope were partially compensated by a higher leaf and stem water storage. While stem hydraulic efficiency did not vary between slopes, leaf hydraulic conductance was between 40% and 300% higher on the NE-facing slope. Changes observed in leaf size and in SLA were consistent with responses to mechanical forces of wind (smaller and scleromorphic leaves on SW-facing slope). Morpho-physiological adjustments observed at a short spatial scale allow maintenance of midday Ψ L above the turgor loss point and demonstrate that leaves are more responsive to microclimatic selective pressures than stems.

The ecological response of fern diversity to different slopes in Gudoushan Nature Reserve, Guangdong

In order to examine the effect of slope differences on fern diversity, we chose 10 plots (5×5 m 2 for each plot) on east-, west-, south-, and north-facing slopes, with altitudes ranging from 20 to 986 m in Gu- doushan Nature Reserve, Xinhui, Guangdong, China. We obtained the following results: (1) Species abun- dance on the east- and north-facing slopes were high, while that on the west- and south-facing slopes were low. (2) Similarity indices of ferns in different slope orientations were low (<0.5), which suggested that ori- entation significantly influenced fern diversity. The difference between the south- and north-facing slopes (similarity index, 0.2895) and the similarity between west- and south-facing slopes (similarity indices, up to 0.4643) were the most obvious. (3) Tropical ferns were dominant in sunny slopes, while non-tropical ferns were dominant in shady slopes. The percentage of tropical ferns on the south-, west-, east-, and north-facing slopes decreased, while that of non-tropical ferns increased. (4) Shade ferns were dominant in shady slopes, while sunny ferns were dominant in sunny slopes; the number of shade ferns regularly increased on the south-, west-, east-, and north-facing slopes. These results clearly indicated how light and heat on different slopes affected fern diversity and suggested that fern diversity could be a good indicator of environmental and climatic changes.

Fire risk map for the Serra de São Domingos Municipal Park, Poços de Caldas, MG

This study constructed a fire risk map for the Serra de São Domingos Municipal Park (SSDMP), southern Minas GeraisSate, Brazil, which harbors Atlantic Forest remnants and endangered species. Geo-processing techniques were used for producing a preliminary risk map for altimetry (a), land slope (e), slope orientation (d), land-use/cover (u) and influence of roads and buildings (i). After, the risk maps were overlaid to produce a structural fire index (SFI)-based risk map for the Park. The SFI was calculated by using the formula SFI = 0,35i + 0,30u + 0,15d + 0,10a + 0,10e. The risks classes were classified as low (0.0-0.9), moderate (1.0 1.9), high (2.0-2.9), very high (3.0-3.9) and extreme (4.0-5.0). All data were processed with 2.5 m base spatial resolution by using the ArcView GIS. According to the SFI calculated, the SSMP area can be divided into the following fire risk zones: Low (0.93%), Moderate (61.77%), High (31.32%), Very High (4.79%) and Extreme (1.19%). The main risk factor is due to the influence of roads and buildings and most fires start due to anthropogenic causes. The low and moderate risk classes comprehend most of the rainforest area. Clearings and grasslands fit mainly the High risk class. The most vulnerable area of SSDMP was the Northern area bordering pasture, crops and eucalypt fields. The SFI map can be a valuable tool for elaborating a fire prevention plan in a small conservation unit when few climate and fire occurrence data are available.

Topographic influences on development of Martian valley networks

[1] Some morphometric differences between terrestrial and Martian valley networks may reflect the precursor topography on Mars, particularly impact basins or tectonic slopes. To evaluate these possible influences, we mapped highland watersheds in nine study areas that sample a range of geographic and topographic settings. We collected data including latitude, longitude, watershed length, divide and terminal elevations, watershed relief and slope, slope orientation, and qualitative descriptors including whether a drainage basin was open or closed. The longest valley networks and most overflowed basins occur on preexisting intercrater slopes of 0.1–1°, particularly on north facing slopes associated with the crustal dichotomy. The control of watershed length by earlier Noachian topographic features, which the relict networks did not significantly modify, suggests that the Early to Middle Noachian geomorphic environment was nominally much drier than the later Noachian to Hesperian transition. The distribution of fluvial valleys and likely orographic effects created by the crustal dichotomy suggest that evaporation from the northern lowlands was an important source of atmospheric humidity over short time scales. Much of the highland plateau consists of smaller enclosed watersheds, which (along with cooler temperatures) detained surface water at high elevations, lengthening or impeding the global water cycle. Ponding and evaporation may have partly offset a continentality effect of the highland landmass. Prolonged modification of the intercrater geomorphic surface prior to incision of valley networks included substantial weathering, reduction of relief, and gravity-driven sediment transport, indicating a long-term role for surface water in a transport-limited, arid to hyperarid Noachian paleoclimate.

Short-term variations of deep water masses in Drake Passage revealed by a multiparametric analysis of the ANT-XXIII/3 bottle data

A multiparametric analysis is applied on the ANT-XXIII/3 bottle data to determine the spreading and mixing of water masses across Drake Passage during January–February 2006, focusing our interest on the flow of the deep water masses. Mixing proportions are quantified along both the southward and northward journeys between the tip of South America and the Antarctic Peninsula. The method is sensitive enough to detect a marked variability in the flow pathways of the Circumpolar Deep Water, the Southeast Pacific Deep Water (SPDW) and the Weddell Sea Deep Water at the intersection of the Shackleton Fracture Zone (SFZ) and the West Scotia Ridge (WSR) between the southward and northward journeys. Indeed the presence of a sharp meander of the southern branch of the Polar Front (PF S) together with the displacement of the northern branch of the Southern Antarctic Circumpolar Current Front (SACCF N) above the complex bathymetric structure of the WSR induced a strong perturbation in the deep flow field during the southward journey. The height of the SFZ crests clearly sets the lower limit of the SPDW in the Ona Basin. An enhanced δ 3He signature is confined to the north of the Polar Front between 55.5°S and 56.5°S in the 1500–2200 m depth range. It clearly indicates the signature of the core of the Southeast Pacific Deep Slope Water. The entry pathway in the ACC of the SPDSW during ANT-XXIII/3 was farther to the south off the continental slope of South America than it was during the WOCE A21 expedition in 1990, probably due to the sharp changes in the slope orientation at the extreme tip of the South America.

Slope orientation assessment for open-pit mines, using GIS-based algorithms

Standard stability analysis in geomechanical rock slope engineering for open-pit mines relies on a simplified representation of slope geometry, which does not take full advantage of available topographical data in the early design stages of a mining project; consequently, this may lead to nonoptimal slope design. The primary objective of this paper is to present a methodology that allows for the rigorous determination of interramp and bench face slope orientations on a digital elevation model (DEM) of a designed open pit. Common GIS slope algorithms were tested to assess slope orientations on the DEM of the Meadowbank mining project's Portage pit. Planar regression algorithms based on principal component analysis provided the best results at both the interramp and the bench face levels. The optimal sampling window for interramp was 21×21 cells, while a 9×9-cell window was best at the bench level. Subsequent slope stability analysis relying on those assessed slope orientations would provide a more realistic geometry for potential slope instabilities in the design pit. The presented methodology is flexible, and can be adapted depending on a given mine's block sizes and pit geometry.

Comparison between open-site and below-canopy climatic conditions in Switzerland for different types of forests over 10 years (1998−2007)

We compared below-canopy and open-site climatic conditions for 14 different forest sites in Switzerland and analysed the forest influence on local summer and winter climate according to the forest type (coniferous, mixed, deciduous), soil type, slope orientation, basal area and tree height. We compared below-canopy and open-field data for minimum, maximum and daily mean temperature, relative humidity, maximum and daily mean photosynthetically active radiation (PAR) and wind speed from 1998 to 2007. We found clear differences between below-canopy and open-field temperatures, humidity, wind speed and PAR and could relate them to the specific site conditions and forest type. The forest influence on PAR and maximum temperature is clearly determined by the forest type, whereas the influence on minimum temperature is affected by both forest type and slope orientation and impact on humidity depends on the soil type. The wind speed is most impacted by topography and slope orientation.

Groundwater discharge and gully formation on martian slopes

Young gullies and gully deposits on walls of martian craters have been cited as evidence that liquid water flowed on the surface of Mars relatively recently. Effects of variable environmental conditions at the surface of Mars are modeled and applied to the case of groundwater emergence from shallow aquifers to investigate whether groundwater is a viable source to enable the erosion of these gullies. The model includes detailed treatment of ice growth in the aquifer. Model results indicate that groundwater discharge can be maintained under the current environmental conditions if the aquifer permeability is like that of terrestrial gravel or higher, if the aquifer is 350 K or warmer, or if the aquifer is a brine with a freezing point depressed to 250 K or below. Groundwater discharge cannot be maintained for the conservative case of a cold, pure water, semi-pervious aquifer. Cold (275 K) pure water pervious (gravel) aquifers, warm (350 K) pure water semi-pervious aquifers, and cold (275 K) CaCl 2 brine semi-pervious aquifers all exhibit a dependence of discharge on season, latitude and slope orientation in our modeling. Seasonal, latitudinal and azimuthal discharge variations are strongest for cold CaCl 2 brine semi-pervious aquifers, with discharges from this aquifer type favoring equator-facing slopes at mid and high southern latitudes. At all latitudes and slope azimuths under our nominal conditions, the cold pure water pervious aquifer, the cold pure water semi-pervious aquifer and the cold CaCl 2 brine semi-pervious aquifer all freeze completely shortly after the simulations are started. Discharge restarts in the summer for the cold pure water pervious aquifer and the cold brine aquifer, but discharge does not restart for the cold pure water semi-pervious aquifer. The warm pure water semi-pervious aquifer maintains daily seeps throughout the year at all but high latitudes. In the case of the cold pure water pervious aquifer, approximately 500,000 m 3 of water could be discharged from a mid-latitude, 150-m thick aquifer with a 20-m wide seepage face orientated towards the equator or the pole after a single undermining-induced event before ice growth seals the seepage face. For a brine semi-pervious aquifer with the same dimensions, 200–300 m 3 of water could be released from a mid-latitude 20-m wide equator-facing seepage face before the fresh exposure is sealed for the fall and winter seasons. Our results do not rule out groundwater emergence as a means of creating some recent gullies, but they indicate that rather special and perhaps unusual conditions would be required.