Active aeolian processes on Mars: A regional study in Arabia and Meridiani Terrae

USGS Publications Warehouse

Silvestro, S.; Vaz, D.A.; Fenton, L.K.; Geissler, P.E.

2011-01-01

We present evidence of widespread aeolian activity in the Arabia Terra/Meridiani region (Mars), where different kinds of aeolian modifications have been detected and classified. Passing from the regional to the local scale, we describe one particular dune field in Meridiani Planum, where two ripple populations are distinguished by means of different migration rates. Moreover, a consistent change in the ripple pattern is accompanied by significant dune advancement (between 0.4-1 meter in one Martian year) that is locally triggered by large avalanche features. This suggests that dune advancement may be common throughout the Martian tropics. ?? 2011 by the American Geophysical Union.

Fresh Shallow Valleys (FSVs) in Northern Arabia Terra, Mars

NASA Astrophysics Data System (ADS)

Wilson, S. A.; Howard, A. D.; Moore, J. M.

2014-12-01

Fresh Shallow Valleys (FSVs) on Mars are part of a growing inventory of post-Noachian landforms that may be related to late, widespread aqueous activity that occurred during a period once thought to be less favorable for precipitation and runoff. Constraining the source, magnitude, timing and duration of FSVs will provide insight into the mechanism and extent of fluvial activity on Mars and the geologic and climatic environments in which they formed. Unlike the older Noachian-Hesperian valleys that are characterized by integrated, dissected and degraded networks that cover large spatial extents, FSVs are typically narrow, short or discontinuous valleys with low drainage densities. They are generally incised no more than a few decameters, slightly degraded at multi-meter scales, and cluster in the mid-latitudes (35-50° in both hemispheres). A high concentration of FSVs occurs in Northern Arabia Terra (~33°N, 8°E), a Noachian-aged landscape characterized by broad, irregular depressions. Many of the FSVs in this region are 150+ km long and some appear to cross depressions that were likely filled with ice or water at the time of formation. Examples of broad, flat floored FSVs with incised channels could either indicate a complex history of a single flow event or multiple flow events. The occurrence of "pollywogs," fairly fresh, small (typically 2-10 km in diameter) craters with a single channel extending from the rim outward, implies overflow of the crater, the presence of a deep lake and the involvement of artesian groundwater flow. Roughly 25% of the FSVs in our northern Arabia Terra study region occur on relatively fresh crater ejecta, which may be related to formation age, topography, surface materials and (or) substrate. Ejecta with dense concentrations of FSVs average 25.5 km in diameter, have more degraded crater interiors, and well developed petal-like ejecta. Ejecta with sparse or no FSVs have radial ejecta with less distinct petals and are associated with

Subsidence and Collapse Activity in Arabia Terra, Mars: Which Link with Magmatic Activity?

NASA Astrophysics Data System (ADS)

Mangold, N.; Howard, A. D.

2014-12-01

Collapsed terrains have been observed using Viking images in the northern part of Arabia Terra from Ismenius Lacus to Deuteronilus Mensae. Recent interpretations of some of these depressions as explosive volcanoes (Michalski and Bleacher, 2013) have renewed the interest for this region. However, recent observations also show the discovery in this region of a series of outflow channels named Okavango Valles (Mangold and Howard, 2013). These channels formed in the Hesperian through catastrophic flows having deposited sediments as deltas in ephemeral lakes. The source area of these channels takes place in a region of widespread depressions and local collapse pits. A continuum of landforms exists from broad depressions (~100 km in length and 100s m in depth) and sharper collapse structures (<100 km in diameter). Given the link between these depressions and the presence of outflow channels, we interpret the collapse structures as resulting from a specific lithology with volatile-rich sediments (or megaregolith) buried at depth. Collapse may be due either to the melting of subsurface ice, or subsurface flows triggered by a change in the groundwater table, or the (less likely) dissolution of buried chemical sediments. Magmatic activity is not excluded: a regionally enhanced thermal flux during the Hesperian could have triggered ground ice melting, and could have initiated subsidence subsequently, but explosive volcanism at the surface is not necessary to explain the presence of large collapsed terrains. Michalski, J. and J. Bleacher, 2013. Supervolcanoes within an ancient volcanic province in Arabia Terra, Mars, Nature, doi:10.1038/nature12482 Mangold N., and A. D. Howard, 2013. Outflow channels with deltaic deposits in Ismenius Lacus, Mars, Icarus, doi.org/10.1016/j.icarus.2013.05.040

Low Albedo Surfaces and Eolian Sediment: Mars Orbiter Camera Views of Western Arabia Terra Craters and Wind Streaks

NASA Technical Reports Server (NTRS)

Edgett, Kenneth S.

2001-01-01

High spatial resolution (1.5 to 12 m/pixel) Mars Global Surveyor Mars Orbiter Camera images obtained September 1997 through June 2001 indicate that the large, dark wind streaks of western Arabia Terra each originate at a barchan dune field on a crater floor. The streaks consist of a relatively thin coating of sediment deflated from the dune fields and their vicinity. This sediment drapes a previous mantle that more thickly covers nearly all of western Arabia Terra. No dunes or eolian bedforms are found within the dark wind streaks, nor do any of the intracrater dunes climb up crater walls to provide sand to the wind streaks. The relations between dunes, wind streak, and subjacent terrain imply that dark-toned grains finer than those which comprise the dunes are lifted into suspension and carried out of the craters to be deposited on the adjacent terrain. Such grains are most likely in the silt size range (3.9-62.5 micrometers). The streaks change in terms of extent, relative albedo, and surface pattern over periods measured in years, but very little evidence for recent eolian activity (dust plumes, storms, dune movement) has been observed.

A Quantitative Analysis of the Fretted Terrain Valleys, Arabia Terra, Mars

NASA Astrophysics Data System (ADS)

Mason, Kelsey Anne

Fretted terrain describes regions on Mars with low-lying, flat valleys separated by steep cliffs that often form polygonal-shaped mesas. The fretted terrain valleys have a morphology distinct from other valleys found on Mars, and their unknown origin may hold insights into critical questions about Mars' tectonic, magmatic, and hydrologic history. Current hypothesis for the formation of the fretted terrain include fracturing as well as hydrological flow processes such as fluvial or glacial erosion. The region for this study is located in eastern Arabia Terra and is the type-location for fretted terrain. By qualitatively and quantitatively documenting the planform, or map-view, valley geometries and orientations throughout the fretted terrain, this study better constrains the origin of the valleys. Valleys were mapped using automated routines in ArcGIS including the D8 flow direction algorithm. Valleys were then grouped geographically into basins and also by Strahler order. The valleys were then segmented every 50 km and the azimuth of each segment was calculated. The resulting valley azimuths were analyzed using rose diagrams to quantitatively describe the planform geometries of the valleys. Qualitatively, the majority of basins were found to have rectangular valley geometries. The downslope direction was calculated for each basin, and it was compared to the corresponding valley azimuths. The basins with rectangular valley geometries had valleys with an azimuth mode nearly parallel to the downslope direction and another azimuth mode perpendicular to the downslope direction. The valley azimuth mode parallel to the downslope direction is attributed to hydrological flow processes while the mode perpendicular to the downslope direction is attributed to fracturing related to the formation or existence of the Mars global dichotomy boundary.

The sedimentology and dynamics of crater-affiliated wind streaks in western Arabia Terra, Mars and Patagonia, Argentina

USGS Publications Warehouse

Rodriguez, J.A.P.; Tanaka, K.L.; Yamamoto, A.; Berman, D.C.; Zimbelman, J.R.; Kargel, J.S.; Sasaki, S.; Jinguo, Y.; Miyamoto, H.

2010-01-01

Wind streaks comprise recent aeolian deposits that have been extensively documented on Venus, Earth and Mars. Martian wind streaks are among the most abundant surface features on the planet and commonly extend from the downwind margins of impact craters. Previous studies of wind streaks emerging from crater interior deposits suggested that the mode of emplacement was primarily related to the deposition of silt-sized particles as these settled from plumes. We have performed geologic investigations of two wind streaks clusters; one situated in western Arabia Terra, a region in the northern hemisphere of Mars, and another in an analogous terrestrial site located in southern Patagonia, Argentina, where occurrences of wind streaks emanate from playas within maar craters. In both these regions we have identified bedforms in sedimentary deposits on crater floors, along wind-facing interior crater margins, and along wind streaks. These observations indicate that these deposits contain sand-sized particles and that sediment migration has occurred via saltation from crater interior deposits to wind streaks. In Arabia Terra and in Patagonia wind streaks initiate from crater floors that contain lithic and evaporitic sedimentary deposits, suggesting that the composition of wind streak source materials has played an important role in development. Spatial and topographic analyses suggest that regional clustering of wind streaks in the studied regions directly correlates to the areal density of craters with interior deposits, the degree of proximity of these deposits, and the craters' rim-to-floor depths. In addition, some (but not all) wind streaks within the studied clusters have propagated at comparable yearly (Earth years) rates. Extensive saltation is inferred to have been involved in its propagation based on the studied terrestrial wind streak that shows ripples and dunes on its surface and the Martian counterpart changes orientation toward the downslope direction where it

Investigating Mars: Arabia Terra Dunes

NASA Image and Video Library

2018-03-21

This image is located southeast of the region of the large sand dune deposit. Here there is still limited amounts of available sand and the dunes formed are smaller individual features. The rocky floor of the crater is visible between the dunes. In some places the floor is relatively free of hills and mesas, while other locations are dense with features. The hills and mesas in the crater can range up to several hundreds of meters tall. Located in eastern Arabia is an unnamed crater, 120 kilometers (75 miles) across. The floor of this crater contains a large exposure of rocky material, a field of dark sand dunes, and numerous patches of what is probably fine-grain sand. The shape of the dunes indicate that prevailing winds have come from different directions over the years. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 37799 Latitude: 26.2544 Longitude: 63.1648 Instrument: VIS Captured: 2010-06-22 17:06 https://photojournal.jpl.nasa.gov/catalog/PIA22300

Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III; Crown, David A.

2009-01-01

Geologic mapping studies at the 1:1M-scale are being used to assess geologic materials and processes that shape the highlands along the Arabia Terra dichotomy boundary. In particular, this mapping will evaluate the distribution, stratigraphic position, and lateral continuity of compositionally distinct outcrops in Mawrth Vallis and Nili Fossae as identified by spectral instruments currently in orbit. Placing these landscapes, their material units, structural features, and unique compositional outcrops into spatial and temporal context with the remainder of the Arabia Terra dichotomy boundary may provide constraints on: 1) origin of the dichotomy boundary, 2) paleo-environments and climate conditions, and 3) various fluvial-nival modification processes related to past and present volatile distribution and their putative reservoirs (aquifers, lakes and oceans, surface and ground ice) and the influences of nearby volcanic and tectonic features on hydrologic processes in these regions. The results of this work will include two 1:1M scale geologic maps of twelve MTM quadrangles (Mawrth Vallis - 20022, 20017, 20012, 25022, 25017, and 25012; and Nili Fossae - 20287, 20282, 25287, 25282, 30287, 30282).

Investigating Mars: Arabia Terra Dunes

NASA Image and Video Library

2018-03-20

The bottom of this image shows the hills and mesas within the crater. The dunes at the top of the image are engulfing and covering the hills. In some locations the hills are still a substantial obstacle to the wind. In these cases the wind is blowing sand up against the windward side, but the hill is causing chaotic wind flow around the hill and rather than depositing sand, the wind is actually removing sand on the leeward side of the hill. With continued winds and sand movement the deposition of material will eventually build up along the leeward side of the hill and then engulf the hill on all sides. Located in eastern Arabia is an unnamed crater, 120 kilometers (75 miles) across. The floor of this crater contains a large exposure of rocky material, a field of dark sand dunes, and numerous patches of what is probably fine-grain sand. The shape of the dunes indicate that prevailing winds have come from different directions over the years. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 11781 Latitude: 26.3693 Longitude: 62.693 Instrument: VIS Captured: 2004-08-10 10:40 https://photojournal.jpl.nasa.gov/catalog/PIA22299

Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars: Introductory Report

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III; Crown, David A.

2008-01-01

Geologic mapping studies at the 1:1M-scale will be used to characterize geologic processes that have shaped the highlands along the Arabia Terra dichotomy boundary. In particular, this mapping will evaluate the distribution, stratigraphic position, and lateral continuity of compositionally distinct outcrops in Mawrth Vallis and Nili Fossae as identified by spectral instruments currently in orbit. Placing these landscapes, their material units, structural features, and unique compositional outcrops into spatial and temporal context with the remainder of the Arabia Terra dichotomy boundary will provide the ability to: 1) further test original dichotomy formation hypotheses, 2) constrain ancient paleoenvironments and climate conditions, and 3) evaluate various fluvial-nival modification processes related to past and present volatile distribution and their putative reservoirs (aquifers, lakes and oceans, surface and ground ice) and the influences of nearby volcanic and tectonic features on hydrologic processes in these regions. The result will be two 1:1M scale geologic maps of twelve MTM quadrangles (Mawrth Vallis - 20022, 20017, 20012, 25022, 25017, and 25012; and Nili Fossae - 20287, 20282, 25287, 25282, 30287, 30282).

Ancient Giant Basin/Aquifer System in the Arabia Region, Mars

NASA Technical Reports Server (NTRS)

Dohm, James M.; Barlow, Nadine; Williams, Jean-Pierre; Baker, Victor R.; Anderson, Robert C.; Boynton, William V.; Fairen, Alberto G.; Hare, Trent M.

2004-01-01

Ancient geologic/hydrologic phenomena on Mars observed through the magnetic data [1,2] provide windows to the ancient past through the younger Argyre and Hellas impacts [e.g., 3,4], the northern plains basement [5], and the Tharsis and Elysium magmatic complexes (recently referred to as superplumes [6,7]). These signatures, coupled with highly degraded macrostructures (tectonic features that are tens to thousands of km-long [8]), reflect an energetic planet during its embryonic development (.5 Ga or so of activity) with an active dynamo and magnetosphere [1,2,6]. One such window into the ancient past occurs northwest of the Hellas impact basin in Arabia Terra. Arabia Terra is one of the few water-rich equatorial regions of Mars, as indicated through impact crater [9] and elemental [10,11] information. This region records many unique traits, including stratigraphy, topography, cratering record, structural character, geomorphology, and geophysical, elemental, albedo, and thermal inertia signatures. We interpret these to collectively indicate a possible ancient giant impact basin that later became an important aquifer, as it provided yet another source of water for the formation of putative water bodies that occupied the northern plains [12,13] and addresses possible water-related characteristics that may be observed at the Opportunity landing site. This basin is antipodal to Tharsis and estimated to be at least 3,000 km in diameter.

Discovery of a Plains Caldera Complex and Extinct Lava Lake in Arabia Terra, Mars: Implications for the Discovery of Additional Highland Volcanic Source Regions

NASA Technical Reports Server (NTRS)

Bleacher, Jacob; Michalski, Joseph

2012-01-01

Several irregularly shaped topographic depressions occur near the dichotomy boundary in northern Arabia Terra, Mars. The geomorphology of these features suggests that they formed by collapse, opposed to meteor impact. At least one depression (approx.55 by 85 km) displays geologic features indicating a complex, multi-stage collapse history. Features within and around the collapse structure indicate volcanic processes. The complex occurs within Hesperian ridged plains of likely volcanic origin and displays no crater rim or evidence for ejecta. Instead the depression consists of a series of circumferential graben and down-dropped blocks which also display upper surfaces similar to ridged plain lavas. Large blocks within the depression are tilted towards the crater center, and display graben that appear to have originally been linked with circumferential graben outside of the complex related to earlier collapse events. A nearly 700 m high mound exists along a graben within the complex that might be a vent. The deepest depression displays two sets of nearly continuous terraces, which we interpret as high-stands of a drained lava lake. These features appear similar to the black ledge described during the Kilauea Iki eruption in 1959. A lacustrine origin for the terraces seems unlikely because of the paucity of channels found in or around the depression that could be linked to aqueous surface processes. In addition, there is no obvious evidence for lacustrine sediments within the basin. Together with the presence of significant faulting that is indicative of collapse we conclude that this crater complex represents a large caldera formed in the Late Noachian to Early Hesperian. Other linear and irregular depressions in the region also might be linked to ancient volcanism. If that hypothesis is correct, it suggests that northern Arabia Terra could contain a large, previously unrecognized highland igneous province. Evacuation of magma via explosive and effusive activity

Light-Toned, Layered Outcrops of Northern Terra Meridiani Mars: Viking, Phobos 2, and Mars Global Surveyor Observations

NASA Technical Reports Server (NTRS)

Edgett, Kenneth S.

2002-01-01

System (PDS). The main body of data examined were Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images acquired through 30 September 2002. The data also 2 include Viking orbiter images, a Phobos 2 Termoscan image, MGS Mars Orbiter Laser Altimeter (MOLA) topographic observations, and the products of published Viking Infrared Thermal Mapper (IRTM) and Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) analyses. Through September 2002, over 126,000 MOC images had been acquired, and greater than 600 of the MOC narrow angle (1.5-12 m/pixel) images occur within the portions of Terra Meridiani and southwestern Arabia Terra.

Vernal Crater, SW Arabia Terra: MSL Candidate with Extensively Layered Sediments, Possible Lake Deposits, and a Long History of Subsurface Ice

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Allen, Carlton C.

2007-01-01

Vernal Crater is a Mars Science Laboratory (MSL) landing site candidate providing relatively easy access to extensively layered sediments as well as potential lake deposits. Sediments of Vernal Crater are 400-1200 m below those being investigated by Opportunity in Meridiani Planum, and as such would allow study of significantly older geologic units, if Vernal Crater were selected for MSL. The location of Vernal Crater in SW Arabia Terra provides exceptional scientific interest, as rampart craters and gamma-ray spectrometer (GRS) data from the region suggest a long history of ice/fluids in the subsurface. The potential value of this MSL candidate is further enhanced by reports of atmospheric methane over Arabia, as any insight into the source of that methane would significantly increase our understanding of Mars. Finally, should MSL survive beyond its prime mission, the gentle slope within Vernal Crater would provide a route out of the crater for study of the once ice/fluid-rich plains.

Equatorial Layered Deposits in Arabia Terra, Mars: Facies and Process Variability

NASA Astrophysics Data System (ADS)

Pondrelli, M.; Rossi, A.; van Gasselt, S.; Le Deit, L.; Glamoclija, M.; Cavalazzi, B.; Franchi, F.; Fueten, F.; Hauber, E.; Zegers, T.

2012-12-01

Genetic mechanisms proposed to explain Equatorial Layered Deposits (ELDs) formation include subglacial volcanism, aeolian/airfall, lacustrine, lacustrine/volcanic and spring-fed deposition. ELDs have been frequently shown to consist of sulfates (e.g. Gendrin et al., 2005) that might form as a response to evaporation in a playa environment (Hoefen et al., 2003) or during spring precipitation (e.g. Allen and Oehler, 2008; Rossi et al., 2008). The importance of groundwater-dominated hydrological systems was proposed to explain the formation of light-toned deposits in Meridiani Planum and Arabia Terra (e.g. Andrews-Hanna et al. 2007). Additionally, fluid expulsion processes have been invoked to explain the formation of mounds within the light-toned deposits in Arabia Terra (Allen and Oehler, 2008; Rossi et al., 2008; Pondrelli et al., 2011). Potential for habitable conditions of both playa and spring-related settings (Cavalazzi et al., 2007; Glamoclija et al., 2011) coupled with the high preservation potential within sulfates (Panieri et al., 2010), make these deposits a good candidate to understand the potential past habitability of the planet. In order to investigate ELDs genesis, an area in the vicinity of Firsoff crater, where ELDs are present within and outside the craters, was selected for geological mapping and analysis of the landforms and their association using the available dataset, including CRISM in order to infer ELDs composition. Within Firsoff crater, ELDs form a bulge that can be estimated to be at least a few hundred meters thick, while, outside the craters, ELDs form flat-lying deposits. Although heavily eroded by wind and carved by yardangs, several morphologies within the ELDs in the craters seem to be depositional, which would exclude that the entire Firsoff basin had been originally filled by ELDs. Within craters, ELDs consist of roughly meter thick layers draping and onlapping the substratum. They appear affected by polygonal patterns with no

Stratigraphic Mapping of Intra-Crater Layered Deposits in Arabia Terra from High-Resolution Imaging and Stereo Topography

NASA Astrophysics Data System (ADS)

Annex, A. M.; Lewis, K. W.; Edwards, C. S.

2017-12-01

The Arabia Terra region of Mars, located in the mid-latitudes, hosts a number of crater basins with exposed sedimentary layers and buttes. Our work builds upon previous studies of these sites that suggest that the layers are formed of weakly lithified aeolian material with quasi-periodic expressions explained by changes in planetary orbital elements during formation (Lewis and Aharonson, 2014; Cadieux and Kah, 2015; Stack et al., 2013). In an effort to better understand differences in lateral continuity of these layers, both between and within basins, an extensive mapping effort was conducted on several sites in Arabia Terra with HiRISE stereo targets. Digital terrain models produced using the Ames Stereo Pipeline were mapped to derive bedding plane positions and orientations for each stratum using linear regression. Bed thicknesses were derived from differences in dip-corrected elevation between successive strata. Our study includes additional independent mapping within craters analyzed in previous studies, and expands mapping of these deposits to several new craters in the region unique to this effort. Our sample size in this study is large, including over 700 individually measured strata from multiple sections within each crater. Although bed thicknesses are generally tightly distributed around 12 meters, any changes within a sequence could represent variations in either the dominant forcing factors controlling deposition and/or changes in sedimentation rate. If craters contain correlative sequences, these types of changes could serve as marker horizons across the region with further mapping.

DTM-based automatic mapping and fractal clustering of putative mud volcanoes in Arabia Terra craters

NASA Astrophysics Data System (ADS)

Pozzobon, R. P.; Mazzarini, F. M.; Massironi, M. M.; Cremonese, G. C.; Rossi, A. P. R.; Pondrelli, M. P.; Marinangeli, L. M.

2017-09-01

Arabia Terra is a region of Mars where occurrence of past-water manifests at surface and subsurface. To date, several landforms associated with this activity were recognized and mapped, directly influencing the models of fluid circulation. In particular, within several craters such as Firsoff and an unnamed southern crater, putative mud volcanoes were described by several authors. In fact, numerous mounds (from 30 m of diameter in the case of monogenic cones, up to 3-400 m in the case of coalescing mounds) present an apical vent-like depression, resembling subaerial Azerbaijan mud volcanoes and gryphons. To this date, landform analysis through topographic position index and curvatures based on topography was never attempted. We hereby present a landform classification method suitable for mounds automatic mapping. Their resulting spatial distribution is then studied in terms of self-similar clustering.

Ancient Giant Basin/Aquifer System in the Arabia Region, Mars, and Its Influence on the Evolution of the Highland-Lowland Boundary

NASA Technical Reports Server (NTRS)

Dohm, J. M.; Barlow, N. G.; Williams, Jean-Pierre; Ferris, J. C.; Miyamoto, H.; Baker, V. R.; Boynton, W. V.; Strom, R. G.; Rodriguez, Alexis; Fairen, Alberto G.

2004-01-01

Ancient geologic and hydrologic phenomena on Mars observed through the magnetic data provide windows to the ancient past through the younger Argyre and Hellas impacts, the northern plains basement and the rock materials that mantle the basement, and the Tharsis and Elysium magmatic complexes (recently referred to as superplumes). These signatures, coupled with highly degraded macrostructures (tectonic features that energetic planet during its embryonic development (0.5 Ga or so of activity) with an active dynamo and magnetosphere. One such window into the ancient past occurs northwest of the Hellas impact basin in Arabia Tern. Arabia Terra is one of the few water-rich equatorial regions of Mars, as indicated I through impact crater and elemental information. This region records many unique characteristics, including predominately Noachian materials, a highland-lowland boundary region that is distinct from other boundary regions, the presence of very few macrostructures when compared to the rest of the cratered highlands, the largest region of fretted terrain on Mars, outflow channels such as Mamers Valles that do not have obvious origins, and distinct albedo, thermal inertia, gravity, magnetic, and elemental signatures.

Geological Time on Display in Arabia Terra

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

This scene from the dust covered plains of eastern Arabia Terra portrays a range of geological time. Three craters at the center of the image capture some of this range. Two have the classic bowl-shape of small, relatively recent craters while the one just to the north has seen much more history. Its rim has been scoured away by erosion and its floor has been filled in by material likely of a sedimentary nature. The channels that wind through the scene may be the oldest features present while the relatively dark streaks scattered about could have been produced in the past few years or even months as winds remove a layer of dust to reveal darker material below.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

A cold-wet middle-latitude environment on Mars during the Hesperian-Amazonian transition: Evidence from northern Arabia valleys and paleolakes

NASA Astrophysics Data System (ADS)

Wilson, Sharon A.; Howard, Alan D.; Moore, Jeffrey M.; Grant, John A.

2016-09-01

The growing inventory of post-Noachian fluvial valleys may represent a late, widespread episode of aqueous activity on Mars, contrary to the paradigm that fluvial activity largely ceased around the Noachian-Hesperian boundary. Fresh shallow valleys (FSVs) are widespread from ~30 to 45° in both hemispheres with a high concentration in northern Arabia Terra. Valleys in northern Arabia Terra characteristically start abruptly on steeper slopes and terminate in topographic depressions at elevations corresponding to model-predicted lake levels. Longer valley systems flowed into and out of chains of paleolakes. Minimum discharges based on the dimensions of the incised channel assuming medium to coarse sand-size grains ranges from tens to hundreds of m3 s-1, respectively, consistent with formation via snowmelt from surface or sub-ice flows. Hydrologic calculations indicate the valleys likely formed in hundreds of years or less, and crater statistics constrain the timing of fluvial activity to between the Hesperian and middle Amazonian. Several craters with channels extending radially outward supports evidence for overflow of interior crater lakes possibly fed by groundwater. Most FSVs occur away from young impact craters which make an association with impact processes improbable. The widespread occurrence of FSVs along with their similar morphology and shared modest state of degradation is consistent with most forming during a global interval of favorable climate, perhaps contemporaneous with alluvial fan formation in equatorial and midlatitudes. Evidence for a snowmelt-based hydrology and considerable depths of water on the landscape in Arabia supports a cold, wet, and possibly habitable environment late in Martian history.

Exhuming Crater in Northeast Arabia

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-563, 3 December 2003

The upper crust of Mars is layered, and interbedded with these layers are old, filled and buried meteor impact craters. In a few places on Mars, such as Arabia Terra, erosion has re-exposed some of the filled and buried craters. This October 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example. The larger circular feature was once a meteor crater. It was filled with sediment, then buried beneath younger rocks. The smaller circular feature is a younger impact crater that formed in the surface above the rocks that buried the large crater. Later, erosion removed all of the material that covered the larger, buried crater, except in the location of the small crater. This pair of martian landforms is located near 17.6oN, 312.8oW. The image covers an area 3 km (1.9 mi) wide and is illuminated from the lower left.

The Origin of the Terra Meridiani Sediments: Volatile Transport and the Formation of Sulfate Bearing Layered Deposits on Mars

NASA Technical Reports Server (NTRS)

Niles, P.B.

2008-01-01

The chemistry, sedimentology, and geology of the Meridiani sedimentary deposits are best explained by eolian reworking of the sublimation residue of a large scale ice/dust deposit. This large ice deposit was located in close proximity to Terra Meridiani and incorporated large amounts of dust, sand, and SO2 aerosols generated by impacts and volcanism during early martian history. Sulfate formation and chemical weathering of the initial igneous material is hypothesized to have occurred inside of the ice when the darker mineral grains were heated by solar radiant energy. This created conditions in which small films of liquid water were created in and around the mineral grains. This water dissolved the SO2 and reacted with the mineral grains forming an acidic environment under low water/rock conditions. Subsequent sublimation of this ice deposit left behind large amounts of weathered sublimation residue which became the source material for the eolian process that deposited the Terra Meridiani deposit. The following features of the Meridiani sediments are best explained by this model: The large scale of the deposit, its mineralogic similarity across large distances, the cation-conservative nature of the weathering processes, the presence of acidic groundwaters on a basaltic planet, the accumulation of a thick sedimentary sequence outside of a topographic basin, and the low water/rock ratio needed to explain the presence of very soluble minerals and elements in the deposit. Remote sensing studies have linked the Meridiani deposits to a number of other martian surface features through mineralogic similarities, geomorphic similarities, and regional associations. These include layered deposits in Arabia Terra, interior layered deposits in the Valles Marineris system, southern Elysium/Aeolis, Amazonis Planitia, and the Hellas basin, Aram Chaos, Aureum Chaos, and Ioni Chaos. The common properties shared by these deposits suggest that all of these deposits share a common

Ice-bearing deposits in the southern mid-latitude regions of Terra Cimmeria, Mars

NASA Astrophysics Data System (ADS)

Adeli, S.; Hauber, E.; Jaumann, R.; Michael, G.; Fawdon, P.

2017-09-01

We report here the presence of a newly observed well-preserved glacial-like and ice-bearing deposit, named Valley Fill Deposit (VFD), on the surface of Terra Cimmeria, located in the southern mid-latitude regions of Mars.

Large-scale fluid-deposited mineralization in Margaritifer Terra, Mars

NASA Astrophysics Data System (ADS)

Thomas, Rebecca J.; Potter-McIntyre, Sally L.; Hynek, Brian M.

2017-07-01

Mineral deposits precipitated from subsurface-sourced fluids are a key astrobiological detection target on Mars, due to the long-term viability of the subsurface as a habitat for life and the ability of precipitated minerals to preserve biosignatures. We report morphological and stratigraphic evidence for ridges along fractures in impact crater floors in Margaritifer Terra. Parallels with terrestrial analog environments and the regional context indicate that two observed ridge types are best explained by groundwater-emplaced cementation in the shallow subsurface and higher-temperature hydrothermal deposition at the surface, respectively. Both mechanisms have considerable astrobiological significance. Finally, we propose that morphologically similar ridges previously documented at the Mars 2020 landing site in NE Syrtis Major may have formed by similar mechanisms.

Thinking Like a Wildcatter: Prospecting for Methane in Arabia Terra, Mars

NASA Technical Reports Server (NTRS)

Allen, C. C.; Oehler, D. Z.

2005-01-01

Methane has been detected in the martian atmosphere at a concentration of approximately 10 ppb. The lifetime of such methane against decomposition by solar radiation is approximately 300 years, strongly suggesting that methane is currently being released to the atmosphere. By analogy to Earth, possible methane sources on Mars include active volcanism, hot springs, frozen methane clathrates, thermally-matured sedimentary organic matter, and extant microbial metabolism. The discovery of any one of these sources would revolutionize our understanding of Mars.

Acidalia and Chryse Plains, Mars

NASA Image and Video Library

2000-06-14

Somewhere down there sits the Mars Pathfinder lander and Sojourner rover. This Mars Global Surveyor Mars Orbiter Camera view of the red planet shows the region that includes Ares Vallis and the Chryse Plains upon which both Mars Pathfinder and the Viking 1 landed in 1997 and 1976, respectively. Acidalia Planitia is the dark surface that dominates the center left. The Pathfinder site is immediately south of Acidalia, just left of center in this view. Also shown--the north polar cap is at the top, and Arabia Terra and Sinus Meridiani are to the right. The bluish-white features are clouds. This is a color composite of 9 red and 9 blue image strips taken by the Mars Global Surveyor Mars Orbiter Camera on 9 successive orbits from pole-to-pole during the calibration phase of the mission in March 1999. The color is computer-enhanced and is not shown as it would actually appear to the human eye. http://photojournal.jpl.nasa.gov/catalog/PIA02000

Comparison of Plains Volcanism in the Tempe Terra Region of Mars to the Eastern Snake River Plains, Idaho with Implications for Geochemical Constraints

NASA Technical Reports Server (NTRS)

Weren, S. L.; Sakimoto, S. E. H.; Hughes, S. S.; Gregg, T. K. P.

2004-01-01

The Eastern Snake River Plains (ESRP) in Idaho have long been considered a terrestrial analog for the plains volcanism like that evident in Syria Planum and Tempe Terra, Mars. Both the ESRP and Tempe Terra are sediment-blanketed volcanic fields in areas with significant extensional faulting. Similar volcanic features can be observed throughout both study areas using field analysis and DEMs of the ESRP and the Mars Global Surveyor (MGS) data from Mars. These features include flow fields, low shields, shields with steep summits, and fissure eruptions. A few other volcanic features, such as cinder cones, which suggest variable compositions, volatile interactions, and multiple volcanic events can be seen in both areas. The eruptions in both the ESRP and Tempe Terra generally originate from the fissures creating elongate, multi-vent shields as well as isolated or aligned single vent shields. Many of these show evidence of radial flow patterns from summit craters as well as lava tube fed flows. The volcanoes of Tempe Terra display some of the global latitudinal parameter trends of small volcanoes on Mars. Some of these trends may be explained by the variation of volatile content and compositional variation across Mars. However, within Tempe Terra no significant local latitudinal trends can be seen in edifice attributes and not all variations are explained by global trends. This study builds upon previous studies of the Tempe Terra region and the ESRP in order to develop a more detailed representation of features and topographic data. Using these data we attempt to help constrain the composition and eruptive style of the Tempe Terra volcanoes by correlating them with the similar and quantified ESRP variations.

MOLA Topography of Small Volcanoes in Tempe Terra and Ceraunius Fossae, Mars: Implications for Eruptive Styles

NASA Technical Reports Server (NTRS)

Wong, M. P.; Sakimoto, S. E. H.; Garvin, J. B.

2001-01-01

We use Mars Orbiter Laser Altimeter (MOLA) data to measure small volcanoes in the Tempe Terra and Ceraunius Fossae regions of Mars. We find that previous geometry estimates based on imagery alone are inaccurate, but MOLA data support image-based interpretations of eruptive style. Additional information is contained in the original extended abstract.

Terra Meridiani

NASA Image and Video Library

2002-12-19

This image from NASA Mars Odyssey is located near the equator and the prime meridian of Mars in a region called Terra Meridiani. This is a unique area of Mars that displays layers of material that appear to be in the process of being stripped away.

Tempe Terra

NASA Image and Video Library

2002-12-18

This image from NASA Mars Odyssey is of a region of Mars called Tempe Terra, which is located between the topographically high Tharsis Region and Acidalia Planitia, a large low albedo region of in the Martian northern hemisphere.

Terra Meridiani

NASA Image and Video Library

2003-04-09

This image by NASA Mars Odyssey illustrates the complex terrains within Terra Meridiani. This general region is one of the more complex on Mars, with a rich array of sedimentary, volcanic, and impact surfaces that span a wide range of Martian history.

Extension across Tempe Terra, Mars, from measurements of fault scarp widths and deformed craters

USGS Publications Warehouse

Golombek, M.P.; Tanaka, K.L.; Franklin, B.J.

1996-01-01

Two independent methods, with no common assumptions, have been used to estimate the extension across the heavily deformed Tempe Terra province of the Tharsis region of Mars. One method uses measurements of normal fault scarp width with average scarp slope data for simple grabens and rifts on Mars to estimate the fault throw, which, combined with sparse fault dip data, can be used to estimate extension. Formal uncertainties in this method are only slightly greater than those in other methods, given that the total uncertainty is dominated by the likely uncertainty in the fault dip (assumed to be 60????15??). Measurement of normal fault scarp widths along two N25??-50??W directed traverses across Tempe Terra both yield about 22??16 km of extension (or ???2% strain across the northern traverse and nearly 3% across the southern one). About three quarters of the extension has occurred during the two main phases of Tharsis-related deformation from Middle/Late Noachian to Early Hesperian and from Late Hesperian to Early Amazonian, with more extension closer to the center of Tharsis during the first phase. Extension across the region was also determined by measuring the elongation and elongation direction of all ancient Noachian impact craters without ejecta blankets, which predate most of the deformation. Results have been corrected for initial non circularity of craters, established from similar measurements of young (post deformation) impact craters, yielding a statistically significant mean strain of 1.96??0.35% in a N38????10??W direction across Tempe Terra (extension of ???20??4, comparable in magnitude and direction to the average result from the scarp measurement method). Both methods indicate an average extension for single normal fault scarps (and shortening across wrinkle ridges for the crater method) of ???100 m. The agreement between the results of the two independent methods in overall extension and average single normal fault extension argues that the average

Extension across Tempe Terra, Mars, from measurements of fault scarp widths and deformed craters

NASA Astrophysics Data System (ADS)

Golombek, M. P.; Tanaka, K. L.; Franklin, B. J.

Two independent methods, with no common assumptions, have been used to estimate the extension across the heavily deformed Tempe Terra province of the Tharsis region of Mars. One method uses measurements of normal fault scarp width with average scarp slope data for simple grabens and rifts on Mars to estimate the fault throw, which, combined with sparse fault dip data, can be used to estimate extension. Formal uncertainties in this method are only slightly greater than those in other methods, given that the total uncertainty is dominated by the likely uncertainty in the fault dip (assumed to be 60°+/-15°). Measurement of normal fault scarp widths along two N25°-50°W directed traverses across Tempe Terra both yield about 22+/-16 km of extension (or ~2% strain across the northern traverse and nearly 3% across the southern one). About three quarters of the extension has occurred during the two main phases of Tharsis-related deformation from Middle/Late Noachian to Early Hesperian and from Late Hesperian to Early Amazonian, with more extension closer to the center of Tharsis during the first phase. Extension across the region was also determined by measuring the elongation and elongation direction of all ancient Noachian impact craters without ejecta blankets, which predate most of the deformation. Results have been corrected for initial non circularity of craters, established from similar measurements of young (post deformation) impact craters, yielding a statistically significant mean strain of 1.96+/-0.35% in a N38°+/-10°W direction across Tempe Terra (extension of ~20+/-4, comparable in magnitude and direction to the average result from the scarp measurement method). Both methods indicate an average extension for single normal fault scarps (and shortening across wrinkle ridges for the crater method) of ~100 m. The agreement between the results of the two independent methods in overall extension and average single normal fault extension argues that the average

Landscape of Former Lakes and Streams on Northern Mars

NASA Image and Video Library

2016-09-15

Valleys younger than better-known ancient valley networks on Mars are evident on the landscape in the northern Arabia Terra region of Mars, particularly in the area mapped here with color-coded topographical information overlaid onto a photo mosaic. The area includes a basin informally named "Heart Lake" at upper left (northwest). Data from the Mars Orbiter Laser Altimeter (MOLA) on NASA's Mars Global Surveyor orbiter are coded here as white and purple for lower elevations, yellow for higher elevation. The elevation information is combined with a mosaic of images from the Thermal Emission Imaging System (THEMIS) camera on NASA's Mars Odyssey orbiter, covering an area about 120 miles (about 190 kilometers) wide. The mapped area is centered near 35.91 degrees north latitude, 1 degree east longitude on Mars. These lakes and streams held water several hundred million years after better-known ancient lake environments on Mars, according to 2016 findings. http://photojournal.jpl.nasa.gov/catalog/PIA20838

Physical properties of Oxia/Lunae Planum and Arabia-type units in the central equatorial region of Mars

NASA Technical Reports Server (NTRS)

Strickland, Edwin L., III

1992-01-01

Classification and mapping of surficial units in the central equatorial region of Mars Consortium data identified the relatively dark but 'red' materials that cover Lunae Planum and surround the Meridiani materials of Oxia Palus inertia region of Arabia. Oxia Province consists of the regions dominated by the characteristically dark 'red' Oxia materials, but it includes darker streaks and splotches of relatively 'blue' Meridiani materials and brighter 'red' deposits of dust belonging to Eos Province (the bright 'red' border between Oxia and regional Meridiani deposits to the south) and Xanthe Province (the moderately bright 'red' dust deposits in western Chryse Planitia and its vicinity, including the VL-1 landing site). Two Oxia units were recognized: a darker unit present on Lunae Planum and east of Oxia Palus that have intermediate to high inertias. Oxia Province surrounds the extremely low thermal inertia Arabia Province in the east part of the study area, and occurs as isolated patches within Arabia (often including splotches of Meridiani materials within the Oxia patches). Arabia Province's materials have been widely interpreted as unconsolidated dust deposits which are currently forming at this stage of Mars' precessional climate cycle, although the persistence of stable, moderately strong albedo contracts among Arabia materials has not been addressed in those models. A systematic interpretation of Oxia and Arabia Province materials based on currently available remote sensing data is given.

Columbus crater and other possible groundwater-fed paleolakes of Terra Sirenum, Mars

USGS Publications Warehouse

Wray, J.J.; Milliken, R.E.; Dundas, C.M.; Swayze, G.A.; Andrews-Hanna, J. C.; Baldridge, A.M.; Chojnacki, M.; Bishop, J.L.; Ehlmann, B.L.; Murchie, S.L.; Clark, R.N.; Seelos, F.P.; Tornabene, L.L.; Squyres, S. W.

2011-01-01

Columbus crater in the Terra Sirenum region of the Martian southern highlands contains light-toned layered deposits with interbedded sulfate and phyllosilicate minerals, a rare occurrence on Mars. Here we investigate in detail the morphology, thermophysical properties, mineralogy, and stratigraphy of these deposits; explore their regional context; and interpret the crater's aqueous history. Hydrated mineral-bearing deposits occupy a discrete ring around the walls of Columbus crater and are also exposed beneath younger materials, possibly lava flows, on its floor. Widespread minerals identified in the crater include gypsum, polyhydrated and monohydrated Mg/Fe-sulfates, and kaolinite; localized deposits consistent with montmorillonite, Fe/Mg-phyllosilicates, jarosite, alunite, and crystalline ferric oxide or hydroxide are also detected. Thermal emission spectra suggest abundances of these minerals in the tens of percent range. Other craters in northwest Terra Sirenum also contain layered deposits and Al/Fe/Mg-phyllosilicates, but sulfates have so far been found only in Columbus and Cross craters. The region's intercrater plains contain scattered exposures of Al-phyllosilicates and one isolated mound with opaline silica, in addition to more common Fe/Mg-phyllosilicates with chlorides. A Late Noachian age is estimated for the aqueous deposits in Columbus, coinciding with a period of inferred groundwater upwelling and evaporation, which (according to model results reported here) could have formed evaporites in Columbus and other craters in Terra Sirenum. Hypotheses for the origin of these deposits include groundwater cementation of crater-filling sediments and/or direct precipitation from subaerial springs or in a deep (???900 m) paleolake. Especially under the deep lake scenario, which we prefer, chemical gradients in Columbus crater may have created a habitable environment at this location on early Mars. ?? 2011 by the American Geophysical Union.

CD-ROM publication of the Mars digital cartographic data base

NASA Technical Reports Server (NTRS)

Batson, R. M.; Eliason, E. M.; Soderblom, L. A.; Edwards, Kathleen; Wu, Sherman S. C.

1991-01-01

The recently completed Mars mosaicked digital image model (MDIM) and the soon-to-be-completed Mars digital terrain model (DTM) are being transcribed to optical disks to simplify distribution to planetary investigators. These models, completed in FY 1991, provide a cartographic base to which all existing Mars data can be registered. The digital image map of Mars is a cartographic extension of a set of compact disk read-only memory (CD-ROM) volumes containing individual Viking Orbiter images now being released. The data in these volumes are pristine in the sense that they were processed only to the extent required to view them as images. They contain the artifacts and the radiometric, geometric, and photometric characteristics of the raw data transmitted by the spacecraft. This new set of volumes, on the other hand, contains cartographic compilations made by processing the raw images to reduce radiometric and geometric distortions and to form geodetically controlled MDIM's. It also contains digitized versions of an airbrushed map of Mars as well as a listing of all feature names approved by the International Astronomical Union. In addition, special geodetic and photogrammetric processing has been performed to derive rasters of topographic data, or DTM's. The latter have a format similar to that of MDIM, except that elevation values are used in the array instead of image brightness values. The set consists of seven volumes: (1) Vastitas Borealis Region of Mars; (2) Xanthe Terra of Mars; (3) Amazonis Planitia Region of Mars; (4) Elysium Planitia Region of Mars; (5) Arabia Terra of Mars; (6) Planum Australe Region of Mars; and (7) a digital topographic map of Mars.

Wadi As-Sirhan, Saudi Arabia

NASA Image and Video Library

2012-07-09

Acquired by NASA Terra spacecraft on in 2011, this image shows the Wadi As-Sirhan Basin in northwest Saudi Arabia, which has been steadily developing agricultural fields using center pivot irrigation by tapping into fossil ground water.

Hard Knocks in Tyrrhena Terra

NASA Image and Video Library

2017-02-02

NASA Mars Reconnaissance Orbiter observed a small portion of a dark crater floor in the Tyrrhena Terra region of Mars. This is largely ancient hard bedrock that has been cratered by numerous impacts over the eons. http://photojournal.jpl.nasa.gov/catalog/PIA11179

Wind-Eroded Crater Floors and Intercrater Plains, Terra Sabaea, Mars

NASA Astrophysics Data System (ADS)

Irwin, Rossman P.; Wray, James J.; Mest, Scott C.; Maxwell, Ted A.

2018-02-01

Ancient impact craters with wind-eroded layering on their floors provide a record of resurfacing materials and processes on early Mars. In a 54 km Noachian crater in Terra Sabaea (20.2°S, 42.6°E), eolian deflation of a friable, dark-toned layer up to tens of meters thick has exposed more resistant, underlying light-toned material. These layers differ significantly from strata of similar tone described in other regions of Mars. The light-toned material has no apparent internal stratification, and visible/near-infrared spectral analysis suggests that it is rich in feldspar. Its origin is ambiguous, as we cannot confidently reject igneous, pyroclastic, or clastic alternatives. The overlying dark-toned layer is probably a basaltic siltstone or sandstone that was emplaced mostly by wind, although its weak cementation and inverted fluvial paleochannels indicate some modification by water. Negative-relief channels are not found on the crater floor, and fluvial erosion is otherwise weakly expressed in the study area. Small impacts onto this crater's floor have exposed deeper friable materials that appear to contain goethite. Bedrock outcrops on the crater walls are phyllosilicate bearing. The intercrater plains contain remnants of a post-Noachian thin, widespread, likely eolian mantle with an indurated surface. Plains near Hellas-concentric escarpments to the north are more consistent with volcanic resurfacing. A 48 km crater nearby contains similar dark-over-light outcrops but no paleochannels. Our findings indicate that dark-over-light stratigraphy has diverse origins across Mars and that some dark-toned plains with mafic mineralogy are not of igneous origin.

Curiosity's field site in Gale Crater, Mars, in context

NASA Astrophysics Data System (ADS)

Edgett, K. S.; Malin, M. C.

2011-12-01

NASA's Mars rover, Curiosity, is anticipated to land in Gale Crater in August 2012. Gale is a 155 km-diameter impact crater adjacent to the ancient crustal "north-south dichotomy boundary." It contains a mound of layered rock (of yet-unknown proportions of clastic sediment, tephra, and chemical precipitates) ˜5 km-high that was eroded by fluvial, eolian, and mass-movement processes. The stratigraphy includes erosional unconformities representing periods when new impact craters formed and streams cut canyons into layered rock. The majority of known impact sites on Earth are craters that were filled and buried in sediment; examples occur under the Chesapeake Bay and beneath the Chicago O'Hare Airport. The upper crust of Mars, with its relative lack of tectonism, is almost entirely a layered, cratered volume of filled, buried, and complexly-interbedded craters and fluvial systems. Some of these have been exhumed or partly exhumed; some, like Gale, were once filled with extensive rock layers that were eroded to form mounds or mesas. Landforms all across Arabia Terra show that similar materials were also deposited between craters. Gale is of the family of Mars craters that were filled and buried (or nearly so). The highest elevation on the Gale mound exceeds the crater's north rim by ˜2 km and is within 500 m of the highest point on the south rim. Many similar craters occur in Arabia Terra; these are instructive as some contain mounds, others have mesas or buttes or other erosional expressions. Craters within 10s to a few 100s of km of each other typically contain very different materials, as exhibited by varied erosional expression, bedding style, and layer thickness. This suggests that the depositional environments, sources, and physical properties of the deposited material differed from place to place and time to time, even in neighboring settings. The Curiosity site in Gale has the potential to illuminate processes that acted locally and globally on early Mars. In

Candidate Landing Site for the Mars Science Laboratory: Vernal Crater, S.W. ARabia Terra

NASA Technical Reports Server (NTRS)

Paris, K. N.; Allen, C. C.; Oehler, D. Z.

2007-01-01

In the fall of 2009, the Mars Science Laboratory (MSL) will be launched to Mars. The purpose of this mission is to assess biologic potential and geology and to investigate planetary processes of relevance to past habitability. MSL will be able to provide visual, chemical, radiation, and environmental data with its suite of instruments [1]. In order to be selected for the MSL landing site, certain engineering requirements must be met [1] and the area should contain geologic features suggestive of past habitability, so that the overriding science goal of the mission will be attained. There are a total of 33 proposed landing sites as of the first MSL Landing Site Workshop held in Pasadena, CA from May 31st to June 2nd, 2006 [1]. There will be an opportunity to gather high resolution visual and hyperspectral data on all proposed landing sites from the now-orbiting Mars Reconnaissance Orbiter (MRO) which entered martian orbit and began its main science phase in November of 2006 [2]. The data being gathered are from: the high resolution imaging science experiment (HiRISE), the context (CTX) camera and the compact reconnaissance imaging spectrometer (CRISM) onboard the spacecraft. The footprints of these instruments are centered on a single point, and each proposer must submit these coordinates, along with the coordinates of the proposed landing ellipse. Data from these instruments, along with new MOC images and THEMIS mosaics, will be used to enhance our understanding of the geologic and engineering parameters of each site.

Terra Sirenum - False Color

NASA Image and Video Library

2016-03-14

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of Terra Sirenum.

Tyrrhena Terra - False Color

NASA Image and Video Library

2016-03-16

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows a hill in Tyrrhena Terra.

Possible climate-related signals in high-resolution topography of lobate debris aprons in Tempe Terra, Mars

NASA Astrophysics Data System (ADS)

Grindrod, Peter M.; Fawcett, Stephen A.

2011-10-01

Lobate debris aprons are common features in the mid-latitudes of Mars that are assumed to be the result of the flow of ice-rich material. We produce high-resolution digital elevation models of two of these features in the Tempe Terra region of Mars using HiRISE stereo images. We identify two main topographic features of different wavelength using a power spectrum analysis approach. Short wavelength features, between approximately 10 and 20 m in length, correspond to a polygonal surface texture present throughout our study area. Long wavelength features, between approximately 700 and 1800 m in length, correspond to broad ridges that are up to 20 m in amplitude. We interpret both topographic signals to be the likely result of climate change affecting the debris contribution and/or the flow regime of the lobate debris aprons. The apparent surface age of about 300 Ma could be evidence of an astronomical forcing mechanism recorded in these lobate debris aprons at this time in Mars' history.

Remnants of Lost Geology

NASA Image and Video Library

2003-02-07

In this NASA Mars Odyssey image of eastern Arabia Terra, remnants of a once vast layered terrain are evident as isolated buttes, mesas, and deeply-filled craters. The origin of the presumed sediments that created the layers is unknown, but those same sediments, now eroded, may be the source of the thick mantle of dust that covers much of Arabia Terra today. http://photojournal.jpl.nasa.gov/catalog/PIA04400

Terra Sirenum - False Color

NASA Image and Video Library

2016-04-25

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of the plains of Terra Sirenum.

Terra Sirenum - False Color

NASA Image and Video Library

2016-03-15

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of the plains of Terra Sirenum.

Terra Sirenum - False Color

NASA Image and Video Library

2016-05-06

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of the plains of Terra Sirenum.

Terra Sabaea - False Color

NASA Image and Video Library

2016-03-08

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of the plains of Terra Sabaea.

Terra Sabaea - False Color

NASA Image and Video Library

2016-02-01

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image captured by NASA 2001 Mars Odyssey spacecraft shows part of the plains of Terra Sabaea.

Geologic Map of MTM -20012 and -25012 Quadrangles, Margaritifer Terra Region of Mars

USGS Publications Warehouse

Grant, J. A.; Wilson, S.A.; Fortezzo, C.M.; Clark, D.A.

2009-01-01

Mars Transverse Mercator (MTM) -20012 and -25012 quadrangles (lat 17.5 deg - 27.5 deg S., long 345 deg - 350 deg E.) cover a portion of Margaritifer Terra near the east end of Valles Marineris. The map area consists of a diverse assemblage of geologic surfaces including isolated knobs of rugged mountainous material, heavily cratered and dissected ancient highland material, a variety of plains materials, chaotic terrain materials, and one of the highest densities of preserved valleys and their associated deposits on the planet (Saunders, 1979; Baker, 1982; Phillips and others, 2000, 2001). The map area is centered on a degraded, partially filled, ~200-km-diameter impact structure (lat 22 deg S., long 347.5 deg E.), informally referred to as Parana basin, located between Parana Valles to the east and Loire Valles to the west. Parana Valles is a network of multidigitate, mostly east-west-oriented valleys that flowed west and discharged into Parana basin (Grant, 1987, 2000; Grant and Parker, 2002). Loire Valles, broadly comparable in length to the Grand Canyon on Earth, has a deeply incised channel within the map area that originates at the west-northwest edge of Erythraeum Chaos within Parana basin (Grant, 1987, 2000; Grant and Parker, 2002; Strom and others, 2000). Parana and Loire Valles, combined with Samara Valles to the west, form one of the most laterally extensive, well-integrated valley networks on Mars (Grant, 2000) and record a long history of modification by fluvial processes. The origin and morphology of the valley networks, therefore, provide insight into past environmental conditions, whereas their relation with other landforms helps constrain the timing and role of fluvial processes in the evolution and modification of the Margaritifer Terra region.

Tyrrhena Terra - False Color

NASA Image and Video Library

2014-12-12

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of an unnamed crater in Tyrrhena Terra.

Terra Sabaea - False Color

NASA Image and Video Library

2016-02-05

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows a variety of surface materials in the plains of Sabaea Terra.

Terra Cimmeria - False Color

NASA Image and Video Library

2015-07-15

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of the plains of Terra Cimmeria.

Daytime Infrared, Terra Sirenum

NASA Image and Video Library

2002-03-01

This 300-kilometer 186-mile long daytime infrared image of Terra Sirenum, taken by NASA Mars Odyssey spacecraft, displays a wide variety of geologic features. The mottled floor and rim of Kovalkiy Crater is seen at the left north of the image.

Blueberries on Earth and Mars: Correlations Between Concretions in Navajo Sandstone and Terra Meridiani on Mars.

NASA Astrophysics Data System (ADS)

Mahaney, W. C.; Milner, M. W.; Netoff, D.; Dohm, J.; Kalm, V.; Krinsley, D.; Sodhi, R. N.; Anderson, R. C.; Boccia, S.; Malloch, D.; Kapran, B.; Havics, A.

2008-12-01

Concretionary Fe-Mn-rich nodular authigenic constituents of Jurassic Navajo sandstone (moki marbles) bear a certain relationship to similar concretionary forms ('blueberries') observed on Mars. Their origin on Earth is considered to invoke variable redox conditions with underground fluids penetrating porous quartz-rich sandstone leading to precipitation of hematite and goethite-rich material from solution, generally forming around a central nucleus of fine particles of quartz and orthoclase, recently verified by XRD and SEM-EDS analyses. At the outer rim/inner nucleus boundary, bulbous lobes of fine-grained quartz often invade and fracture the outer rim armored matrix. The bulbous forms are interpreted to result from fluid explusion from the inner concretionary mass, a response to pressure changes accompanying overburden loading. Moki marbles, harder than enclosing rock, often weather out of in situ sandstone outcrops that form a surface lag deposit of varnished marbles that locally resemble desert pavement. The marbles appear morphologically similar to 'blueberries' identified on the martian surface in Terra Meridiani through the MER-1 Opportunity rover. On Earth, redox fluids responsible for the genesis of marbles may have emanated from deep in the crust (often influenced by magmatic processes). These fluids, cooling to ambient temperatures, may have played a role in the genesis of the cemented outer rim of the concretions. The low frequency of fungi filaments in the marbles, contrasts with a high occurrence in Fe-encrusted sands of the Navajo formation [1], indicating that microbial content is of secondary importance in marble genesis relative to the fluctuating influx of ambient groundwater. Nevertheless, the presence of filaments in terrestrial concretions hints at the possibility of discovering fossil/extant life on Mars, and thus should be considered as prime targets for future reconnaissance missions to Mars. 1] Mahaney, W.C., et al. (2004), Icarus, 171, 39-53.

Analysis of Ice-Related Intra-Crater Facies in Promethei Terra, Mars

NASA Astrophysics Data System (ADS)

Orgel, Csilla; Kereszturi, Ákos; van Gasselt, Stephan

2014-05-01

On Mars ice-related landforms have been identified at mid-latitudes between 30° and 50° in both hemispheres including the areas of Tempe Terra, Deuteronilus-Protonilus Mensae, Phlegra Montes and the rims of the southern-hemispheric impact basins Argyre and Hellas [1-7]. Our study area - informally termed hourglass-shaped crater [8] - is located near Reull Vallis on the eastern rim of the Hellas impact basin (39.0°S, 102.8°E). Impact-crater infill was described as debris-covered piedmont-type glacier [8] based on analysis of High Resolution Stereo Camera (HRSC) data, and implies a glacial origin with precipitation of ice during higher obliquity phases. Recent, higher-resolution image data such as data of the High Resolution Imaging Science Experiment (HiRISE) and the Context Imager (CTX) provide a more detailed picture of the lateral distribution of different small-scale surface features indicative of periglacial and/or glacial origin. The aim of this study is to identify qualitative and quantitative characteristics of these ice-related landforms and to separate sources of water ice and related processes. Initial age determinations based on impact-crater size-frequency statistics indicate an age of 3.4 Gyr for the impact-crater and an age of approximately 75 Myr for the infill [8]. In order to identify a possible sequence of surface-feature evolution we calculated the age distribution of four major surface units which span ages ages between 1-47 Myr. Along with detailed age information and a separation of different processes at this confined type location of Mars young-Amazonian landscape evolution and potential cyclic signals are being reconstructed to constrain climate evolution. Carr, M. H. & Schaber, G. G. 1977: Martian permafrost features.- J. Geophys. Res. 82, 4039-4054. Squyres, S. W. 1978: Martian fretted terrain: flow of erosional debris.- Icarus 34, 600-613. Squyres, S. W. 1979: The distribution of lobate debris aprons and similar flows on Mars.- J

Cratered terrain in Terra Meridiani

NASA Image and Video Library

2002-05-23

This region of Terra Meridiani, imaged by NASA Mars Odyssey, shows an old, heavily degraded channel that appears to terminate abruptly at the rim of a 10 km diameter crater, suggesting that the impact crater was created after the channel was formed.

Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: Project Introduction and First Year Work Plan

NASA Technical Reports Server (NTRS)

Skiner, J. A., Jr.; Rogers, A. D.; Seelos, K. D.

2009-01-01

The highland-lowland boundary (HLB) of Mars is interpreted to be a complex tectonic and erosional transition that may hold evidence for past geologic processes and environments. The HLB-abutting margin of the Libya Montes and the interbasin plains of northern Tyrrhena Terra display an exceptional view of the earliest to middle history of Mars that has yet to be fully characterized. This region contains some of the oldest exposed materials on the Martian surface as well as aqueous mineral signatures that may be potential chemical artifacts of early highland formational processes. However, a full understanding of the regions geologic and stratigraphic evolution is remarkably lacking. Some outstanding questions regarding the geologic evolution of Libya Montes and northern Tyrrhena Terra in-clude: Does combining geomorphology and composition advance our understanding of the region s evolution? Can highland materials be subdivided into stratigraphically discrete rock and sediment sequences? What do major physiographic transitions imply about the balanced tectonism, climate change, and erosion? Where is the erosional origin and what is the post-depositional history of channel and plains units? When and in what types of environments did aqueous mineral signatures arise? This abstract introduces the geologic setting, science rationale, and first year work plan of a recently-funded 4-year geologic mapping proposal (project year = calendar year). The objective is to delineate the geologic evolution of Libya Montes and northern Tyrrhena Terra at 1:1M scale using both classical geomorphological and compositional mapping techniques. The funded quadrangles are MTMs 00282, -05282, -10282, 00277, -05277, and -10277.

Medusae Fossae-Elysium Region, Mars: Depression in the HEND/Odyssey Map of Mars Epithermal Neutrons

NASA Technical Reports Server (NTRS)

Ivanov, M. A.; Litvak, M. L.; Mitrofanov, I. G.; Boynton, W.; Saunders, R. S.

2003-01-01

The first data from the Gamma Ray Spectrometer (GRS) onboard Mars Odyssey spacecraft showed that the low neutron fluxes characterize both subpolar regions of Mars. The low neutron fluxes mean the presence of hydrogen-rich soils and have been interpreted as an indication on abundant water ice in these areas. The equatorial region of Mars (equatorward of approx. 50 deg) is characterized by higher fluxes of both epithermal (0.4 eV-100 keV, come from depth 1-2 m) and fast (3.4-7.3 MeV, come from depth 0.2-0.3 m) neutrons meaning that this area is mostly dry. The pattern of distribution of the neutron fluxes is in a good agreement with the theoretical predictions on the stability of ground ice on present Mars. The actual distribution of the ice, however, depends on variations of thermal inertia of soils and albedo of the surface. The flux of the epithermal neutrons detected by the HEND instrument, which is part of GRS, has two noticeable depressions in the equatorial region, one in Arabia Terra and another in the Medusae Fossae-Elysium region (MFER). Here we present the initial results of analysis of characteristics of the neutron fluxes and regional geological setting of the epithermal neutron depression in this area. The main goal of our study was to put some constraints on the time of the anomaly formation and to assess possible form of hydrogen (ground ice vs. chemically bound water) there.

Ancient geodynamics and global-scale hydrology on Mars.

PubMed

Phillips, R J; Zuber, M T; Solomon, S C; Golombek, M P; Jakosky, B M; Banerdt, W B; Smith, D E; Williams, R M; Hynek, B M; Aharonson, O; Hauck , S A

2001-03-30

Loading of the lithosphere of Mars by the Tharsis rise explains much of the global shape and long-wavelength gravity field of the planet, including a ring of negative gravity anomalies and a topographic trough around Tharsis, as well as gravity anomaly and topographic highs centered in Arabia Terra and extending northward toward Utopia. The Tharsis-induced trough and antipodal high were largely in place by the end of the Noachian Epoch and exerted control on the location and orientation of valley networks. The release of carbon dioxide and water accompanying the emplacement of approximately 3 x 10(8) cubic kilometers of Tharsis magmas may have sustained a warmer climate than at present, enabling the formation of ancient valley networks and fluvial landscape denudation in and adjacent to the large-scale trough.

Detailed spectroscopic analysis of chloride salt deposits in Terra Sirenum, Mars

NASA Astrophysics Data System (ADS)

Osterloo, M. M.; Glotch, T. D.; Bandfield, J. L.

2015-12-01

Chloride salt-bearing deposits have been identified throughout the southern highlands of Mars [1] based on the lack of diagnostic spectral features of anhydrous chlorides in both the visible near infrared (VNIR) and middle infrared (MIR) wavelength ranges [1,2]. A puzzling aspect of martian chloride deposits is the apparent lack of other weathering or evaporite phases associated with most of the deposits. A global analysis over the chloride salt sites conducted by [3] found that only ~9% of the deposits they analyzed were associated with minerals such as phyllosilicates. Most of these occurrences are in Terra Sirenum where [4] noted that salt-bearing deposits lie stratigraphically above Noachian phyllosilicates. Although a variety of formation mechanisms have been proposed for these intriguing deposits, detailed geologic mapping by [5] suggests that surface water and evaporation played a dominant role. On Earth, evaporative settings are often characterized by a multitude of evaporite and phyllosilicate phases including carbonates, sulfates, and nitrates. [6] evaluated chemical divides and brine evolution for martian systems and their results indicate three pathways wherein late-stage brines favor chloride precipitation. In each case the pathway to chloride formation includes precipitation of carbonates (calcite, siderite, and/or magnesite) and sulfates (gypsum, melanterite, and/or epsomite). Here, we present the results of our detailed and systematic spectroscopic study to identify additional evaporite phases associated with salt/silicate mixtures in Terra Sirenum. [1] Osterloo et al. (2008) Science, 319, [2] Glotch, T. D. et al. (2013) Lunar and Planet. Sci. XLIV, abstract #1549 [3] Ruesch, O. et al. (2012), J. Geophys. Res., 117, E00J13 [4] Glotch, T. D. et al. (2010) Geophys. Res. Lett. 37, L16202, [5] Osterloo, M. M. and B. M Hynek (2015) Lunar and Planet. Sci XLVI. Abstract #1054 [6] Tosca, N. J. and S. M. McLennan (2006), Earth and Planet. Sci. Lett., 241.

Aqueous alteration detection in Tikhonravov crater, Mars

NASA Astrophysics Data System (ADS)

Mancarella, F.; Fonti, S.; Alemanno, G.; Orofino, V.; Blanco, A.

2018-03-01

The existence of a wet period lasting long enough to allow the development of elementary forms of life on Mars has always been a very interesting issue. Given this perspective, the research for geological markers of such occurrences has been continually pursued. Once a favorable site is detected, effort should be spent to get as much information as possible aimed at a precise assessment of the genesis and evolution of the areas showing the selected markers. In this work, we discuss the recent finding of possible deposits pointing to the past existence of liquid water in Tikhonravov crater located in Arabia Terra. Comparison of CRISM spectra and those of laboratory minerals formed by aqueous alteration has led us to the conclusion that the studied areas within the impact crater host phyllosilicates deposits. In addition, analysis of the CRISM spectra has resulted in the tentative identification of carbonates mixed with phyllosilicates.

Exobiology site priorities for Mars Pathfinder

NASA Technical Reports Server (NTRS)

Farmer, Jack D.; Desmarais, David J.

1994-01-01

The fact that life developed on the Earth within the first billion years of its history makes it quite plausible that life may have also developed on Mars. If life did develop on Mars, it undoubtedly left behind a fossil record. Such a fossil record is likely to be more accessible than either subsurface environments that may harbor life, or scattered 'oases' that may be present at the surface. Consequently, the post-Viking approach of Mars exobiology has shifted focus to search for evidence of an ancient martian biosphere. This has led to the emergence of a new subdiscipline of paleontology, herein termed 'exopaleontology', which deals with the exploration for fossils on other planets and whose core concepts derive from Earth-based Precambrian paleontology, microbial ecology, and sedimentology. Potential targets on Mars for subaqueous spring deposits, sedimentary cements, and evaporites are ancient terminal lake basins where hydrological systems could have endured for some time under arid conditions. Potential targets for the Mars Pathfinder mission include channeled impact craters and areas of deranged drainage associated with outflows in northwest Arabia and Xanthe Terra, where water may have ponded temporarily to form lakes. The major uncertainty of such targets is their comparatively younger age and the potentially short duration of hydrological activity compared to older paleolake basins found in the southern hemisphere. However, it has been suggested that cycles of catastrophic flooding associated with Tharsis volcanism may have sustained a large body of water, Oceanus Borealis, in the northern plains area until quite late in martian history. Although problematic, the shoreline areas of the proposed northern ocean provide potential targets for a Mars Pathfinder mission aimed at exploring for carbonates or other potentially fossiliferous marine deposits. Carbonates and evaporites possess characteristic spectra signatures in the near-infrared and should be

Emplacement of Widespread Fe/Mg Phyllosilicate Layer in West Margaritifer Terra, Mars

NASA Astrophysics Data System (ADS)

Seelos, K. D.; Maxwell, R. E.; Seelos, F. P.; Buczkowski, D.; Viviano-Beck, C. E.

2017-12-01

West Margaritifer Terra is located at the eastern end of Valles Marineris at the complex intersection of chaos terrains, cratered highlands, and multiple generations of outflow channels. Adjacent regions host layered phyllosilicates thought to indicate early Mars pedogenic and/or ground water-based alteration (e.g., Le Deit et al., 2012), and indeed, hydrologic modeling supports prolonged aqueous activity in the Noachian and Hesperian eras (Andrews-Hanna and Lewis, 2011). The remnant high-standing plateaus in West Margaritifer (0-15°S, 325-345°E) host numerous phyllosilicate-bearing outcrops as well and are the focus of this study. Here, we performed a systematic mapping and characterization of mineralogy and morphology of these deposits in order to assess similarity to other layered phyllosilicates and evaluate potential formation mechanisms. Utilizing multiple remote sensing datasets, we identified three types of phyllosilicate exposures distributed throughout the region: 1) along upper chaos fracture walls, 2) in erosional windows on the plains, and 3) in crater walls and ejecta. Outcrops are spectrally indicative of Fe/Mg smectite (most similar to saponite) and only rare, isolated occurrences of Al-phyllosilicate were observed. Morphologically, the layer is a few to 10 m thick, light-toned, polygonally fractured at decameter scales, and vertical subparallel banding is evident in places. These characteristics were used along with spatial distribution, elevation, and geologic context to evaluate 4 potential formation mechanisms: fluvio-lacustrine, pedogenesis, diagenesis, and hydrothermal alteration. We find that the widespread distribution and spectral homogeneity of the layer favors formation via groundwater alteration and/or pedogenic weathering. This is consistent with interpretations of similar layered phyllosilicates in NW Noachis Terra and the Valles Marineris plains to the west, and significantly extends the area over which these aqueous processes

Geology of Holden Crater and the Holden and Ladon Multi-Ring Impact Basins, Margaritifer Terra, Mars

NASA Technical Reports Server (NTRS)

Irwin, R. P., III; Grant, J. A.

2008-01-01

Geologic mapping at 1:500K scale of Mars quads 15s027, 20s027, 25s027, and 25s032 (Fig. 1) is in progress to constrain the geologic and geomorphic history of southwestern Margaritifer Terra. This work builds on earlier maps at 1:5M [1] and 1:15M scales [2], recent to concurrent 1:500Kscale mapping of adjacent areas to the east [3-5], and studies of drainage basin evolution along the Uzboi-Ladon-M (ULM; the third valley in the sequence has no formal name) Valles basin overflow system and nearby watersheds [6-9]. Two of the six landing sites under consideration for the Mars Science Laboratory rover are in this map area, targeting finely layered, phyllosilicate-rich strata and alluvial fans in Holden crater [10-12] (26degS, 34degW, 150 km diameter) or deposits southeast of a likely delta in Eberswalde crater [13-16] (24degS, 33degW, 50 km in diameter). Diverse processes including larger and smaller impacts, a wide range in fluvial activity, and local to regional structural influences have all affected the surface morphology.

Geologic map of MTM -15027, -20027, -25027, and -25032 quadrangles, Margaritifer Terra region of Mars

USGS Publications Warehouse

Irwin, Rossman P.; Grant, John A.

2013-01-01

Mars Transverse Mercator (MTM) quadrangles −15027, −20027, −25027, and −25032 (lat 12.5°−28° S., long 330°−335° E. and lat 22.5°−28° S., long 324.5°−330° E.) in southwestern Margaritifer Terra include diverse erosional landforms, sedimentary deposits, and tectonic structures that record a long geologic and geomorphic history. The northeastern regional slope of the pre-Noachian crustal dichotomy (as expressed along the Chryse trough) and structures of the informally named Middle Noachian or older Holden and Ladon impact basins dominate the topography of the map area. A series of mesoscale outflow channels, Uzboi, Ladon, and Morava Valles, integrated these formerly enclosed basins by overflow and incision around the Noachian/Hesperian transition, although some flooding may have occurred earlier. The area includes excellent examples of Late Noachian to Hesperian valley networks, dissected crater rims, alluvial fans, deltas, and light-toned layered deposits, particularly in Holden and Eberswalde craters. Structural forms include Tharsis-radial grabens, Hesperian wrinkle ridges, floor-fractured impact craters, and severely disrupted chaotic terrains. These well-preserved landforms and sedimentary deposits represent multiple erosional epochs and discrete flooding events, which provide significant insight into the geomorphic processes and climate change on early Mars.

Urbanization: Riyadh, Saudi Arabia

NASA Technical Reports Server (NTRS)

2001-01-01

Riyadh, the national capital of Saudi Arabia, is shown in 1972, 1990 and 2000. Its population grew in these years from about a half million to more than two million. Saudi Arabia experienced urbanization later than many other countries; in the early 1970s its urban-rural ratio was still about 1:3. By 1990 that had reversed to about 3:1. The city grew through in-migration from rural areas, and from decreases in the death rate while birthrates remained high. The 1972 image is a Landsat MSS scene; the 1990 image is a Landsat Thematic Mapper scene; and the 2000 image is an ASTER scene. All three images cover an area of about 27 x 34 km. The image is centered at 24.6 degrees north latitude, 46.6 degrees east longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

Tikhonravov's Eyebrows

NASA Technical Reports Server (NTRS)

2005-01-01

1 January 2004 This red wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows Tikhonravov Crater in central Arabia Terra. The crater is about 386 km (240 mi) in diameter and presents two impact craters at its center that have dark patches of sand in them, giving the impression of pupils in two eyes. North (above) each of these two craters lies a dark-toned patch of surface material, providing the impression of eyebrows. M. K. Tikhonravov was a leading Russian rocket engineer in the 20th Century. The crater named for him, despite its large size, is still partly buried, on its west side, beneath the heavily cratered terrain of Arabia Terra. The center of Tikhonravov is near 13.5oN, 324.2oW. Sunlight illuminates the scene from the upper left.

Investigation of the relationship of crater depths and diameters in selected regions of Mars

NASA Astrophysics Data System (ADS)

Hsu, Hsin-Jen

2013-03-01

Impact craters are common geomorphological features on Mars. The density of craters is different among various regions. Higher crater density means older terrain. Craters can be divided into two types by the interior morphology: simple and complex. The cavity of Simple craters is bowl-shape, and complex craters display various interior features, such as central peaks. The depth/diameter ratio (d/D) of simple craters is larger than that of complex craters. The transition diameter from simple to complex morphologies ranges between 5 and 10 km, and is commonly cited to be about 7 km in the equatorial regions and 6 km near the poles, but the exact value also could vary with terrain type. In this research, seven regions, Amazonis Planitia, Arabia Terra, Chryse Planitia, Hesperia Planum, Isidis Planitia, Solis/Syria/Sinai Planum, and Terra Sirenum, were selected to investigate the onset diameter of complex craters and the relationship of crater diameter and depth in these regions on Mars in order to understand how the geology affects crater d/D. The analysis revealed that the slopes of the d/D relations are different, and these are linked to the surface material in different regions. The onset diameters in young volcanic regions with stronger material are slightly higher than older volcanic regions, and much higher than that of volatile regions. The research proves the different geological units can affect the morphology and morphometry of craters.

Ripple Belt

NASA Technical Reports Server (NTRS)

2006-01-01

16 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown materials that have collected and been shaped into large ripples in a valley in the Auqakuh Vallis system in northeastern Arabia Terra, Mars.

Location near: 29.1oN, 299.6oW Image width: 2 km (1.2 mi) Illumination from: lower left Season: Northern Winter

Variations in Crustal Structure, Lithospheric Flexural Strength, and Isostatic Compensation Mechanisms of Mars

NASA Astrophysics Data System (ADS)

Ding, M.; Lin, J.; Zuber, M. T.

2014-12-01

We analyze gravity and topography of Mars to investigate the spatial variations in crustal thickness, lithospheric strength, and mechanisms of support of prominent topographic features on Mars. The latest gravity model JGMRO110c (released in 2012) from the Mars Reconnaissance Orbiter mission has a spatial block size resolution of ~97 km (corresponding to degree-110), enabling us to resolve crustal structures at higher spatial resolution than those determined from previous degree-80 and 85 gravity models [Zuber et al., 2000; McGovern et al., 2002, 2004; Neumann et al., 2004; Belleguic et al., 2005]. Using the latest gravity data, we first inverted for a new version of crustal thickness model of Mars assuming homogeneous crust and mantle densities of 2.9 and 3.5 g/cm3. We calculated "isostatic" topography for the Airy local isostatic compensation mechanism, and "non-isostatic" topography after removing the isostatic part. We find that about 92% of the Martian surface is in relatively isostatic state, indicating either relatively small lithospheric strength and/or small vertical loading. Relatively isostatic regions include the hemispheric dichotomy, Hellas and Argyre Planitia, Noachis and Arabia Terra, and Terra Cimmeria. In contrast, regions with significant amount of non-isostatic topography include the Olympus, Ascraeus, Arsia, Pavonis, Alba, and Elysium Mons, Isidis Planitia and Valles Marineris. Their relatively large "non-isostatc topography" implies relatively strong lithospheric strength and large vertical loading. Spectral analysis of the admittance and correlation relationship between gravity and topography were conducted for the non-isostatic regions using the localized spectra method [Wieczorek and Simons, 2005, 2007] and thin-shell lithospheric flexural approximation [Forsyth, 1985; McGovern et al., 2002, 2004]. The best-fitting models reveal significant variations in the effective lithospheric thickness with the greatest values for the Olympus Mon

Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: First Year Results and Second Year Work Plan

NASA Technical Reports Server (NTRS)

Skinner, J. A., Jr.; Rogers, A. D.; Seelos, K. D.

2010-01-01

The Libya Montes-Tyrrhena Terra highland-lowland transitional zone of Mars is a complex tectonic and erosional region that contains some of the oldest exposed materials on the Martian surface as well as aqueous mineral signatures that may be potential chemical artifacts of early highland formational processes. Our 1:1M scale mapping project includes the geologic materials and landforms contained within MTMs 00282, -05282, -10282, 00277, - 05277, and -10277, which cover the highland portion of the transitional zone. The map region extends from the Libya Montes southward into Tyrrhena Terra and to the northern rim of Hellas basin and includes volcanic rocks of Syrtis Major Planum and a broad lowlying plain (palus) that forms a topographic divide between Isidis and Hellas basins. The objective of this project is to describe the geologic history of regional massif and plains materials by combining geomorphological and compositional mapping observations. This abstract summarizes the technical approaches and interim scientific results of Year 1 efforts and the expected work plan for Year 2 efforts.

Wadi Al Dawasir, Saudi Arabia

NASA Image and Video Library

2015-10-20

In the middle of the Arabian desert the city Green Oasis Wadi Al Dawasir is being developed as a new urban center for the Wadi Al Dawasir region of Saudi Arabia, as shown in this image from NASA Terra spacecraft. Huge solar fields supply the entire city and the surrounding region with energy. Hundreds of circular agricultural fields are fed by center pivot irrigation apparatus, drawing water from subterranean aquifers. The image was acquired March 30, 2013, covers an area of 30 x 45 km, and is located at 20.2 degrees north, 44.8 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20077

Mars Global Surveyor Approach Image

NASA Technical Reports Server (NTRS)

1997-01-01

This image is the first view of Mars taken by the Mars Global Surveyor Orbiter Camera (MOC). It was acquired the afternoon of July 2, 1997 when the MGS spacecraft was 17.2 million kilometers (10.7 million miles) and 72 days from encounter. At this distance, the MOC's resolution is about 64 km per picture element, and the 6800 km (4200 mile) diameter planet is 105 pixels across. The observation was designed to show the Mars Pathfinder landing site at 19.4 N, 33.1 W approximately 48 hours prior to landing. The image shows the north polar cap of Mars at the top of the image, the dark feature Acidalia Planitia in the center with the brighter Chryse plain immediately beneath it, and the highland areas along the Martian equator including the canyons of the Valles Marineris (which are bright in this image owing to atmospheric dust). The dark features Terra Meridiani and Terra Sabaea can be seen at the 4 o`clock position, and the south polar hood (atmospheric fog and hazes) can be seen at the bottom of the image. Launched on November 7, 1996, Mars Global Surveyor will enter Mars orbit on Thursday, September 11 shortly after 6:00 PM PDT. After Mars Orbit Insertion, the spacecraft will use atmospheric drag to reduce the size of its orbit, achieving a circular orbit only 400 km (248 mi) above the surface in early March 1998, when mapping operations will begin.

The Mars Global Surveyor is operated by the Mars Surveyor Operations Project managed for NASA by the Jet Propulsion Laboratory, Pasadena CA. The Mars Orbiter Camera is a duplicate of one of the six instruments originally developed for the Mars Observer mission. It was built and is operated under contract to JPL by an industry/university team led by Malin Space Science Systems, San Diego, CA.

Terra Sirenum

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

This image is from a region called Terra Sirenum in Mars' southern hemisphere. This region was named in 1958 for the Sea of the Sirens from Greek Mythology. This is not a sea, however, but a relatively dusty, high albedo region of Mars. There are numerous dust devil tracks that are apparent in the center- left of the image. The dust devils act like vacuum cleaners and lift dust off of the surface leaving a less dusty and relatively lower albedo surface behind. Dust devils are very common on Mars and are thought to be the primary mechanism for constantly lifting the dust into the atmosphere. Dust is constantly present in the Martian atmosphere in greater abundances than typically seen on Earth. The Martian dust is one of the main factors that affect the present Martian climate and clearly displays the relationship between Mars' geology and atmosphere.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California

Open Access Discovery of alunite in Cross crater, Terra Sirenum, Mars: Evidence for acidic, sulfurous waters

USGS Publications Warehouse

Ehlmann, Bethany L.; Swayze, Gregg A.; Milliken, Ralph E.; Mustard, John F.; Clark, Roger N.; Murchie, Scott L.; Breit, George N.; Wray, James J.; Gondet, Brigitte; Poulet, Francois; Carter, John; Calvin, Wendy M.; Benzel, William M.; Seelos, Kimberly D.

2016-01-01

Cross crater is a 65 km impact crater, located in the Noachian highlands of the Terra Sirenum region of Mars (30°S, 158°W), which hosts aluminum phyllosilicate deposits first detected by the Observatoire pour la Minéralogie, L’Eau, les Glaces et l’Activitié (OMEGA) imaging spectrometer on Mars Express. Using high-resolution data from the Mars Reconnaissance Orbiter, we examine Cross crater’s basin-filling sedimentary deposits. Visible/shortwave infrared (VSWIR) spectra from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show absorptions diagnostic of alunite. Combining spectral data with high-resolution images, we map a large (10 km × 5 km) alunite-bearing deposit in southwest Cross crater, widespread kaolin-bearing sediments with variable amounts of alunite that are layered in <10 m scale beds, and silica- and/or montmorillonite-bearing deposits that occupy topographically lower, heavily fractured units. The secondary minerals are found at elevations ranging from 700 to 1550 m, forming a discontinuous ring along the crater wall beneath darker capping materials. The mineralogy inside Cross crater is different from that of the surrounding terrains and other martian basins, where Fe/Mg-phyllosilicates and Ca/Mg-sulfates are commonly found. Alunite in Cross crater indicates acidic, sulfurous waters at the time of its formation. Waters in Cross crater were likely supplied by regionally upwelling groundwaters as well as through an inlet valley from a small adjacent depression to the east, perhaps occasionally forming a lake or series of shallow playa lakes in the closed basin. Like nearby Columbus crater, Cross crater exhibits evidence for acid sulfate alteration, but the alteration in Cross is more extensive/complete. The large but localized occurrence of alunite suggests a localized, high-volume source of acidic waters or vapors, possibly supplied by sulfurous (H2S- and/or SO2-bearing) waters in contact with a magmatic source, upwelling

Hubble Takes Mars Portrait Near Close Approach

NASA Image and Video Library

2017-12-08

Mars is looking mighty fine in this portrait nabbed by the Hubble Space Telescope on a near close approach! Read more: go.nasa.gov/1rWYiBT The Hubble Space Telescope is more well known for its picturesque views of nebulae and galaxies, but it's also useful for studying our own planets, including Mars. Hubble imaged Mars on May 12, 2016 - ten days before Mars would be on the exact opposite side of the Earth from the Sun. Bright, frosty polar caps, and clouds above a vivid, rust-colored landscape reveal Mars as a dynamic seasonal planet in this NASA Hubble Space Telescope view taken on May 12, 2016, when Mars was 50 million miles from Earth. The Hubble image reveals details as small as 20 to 30 miles across. The large, dark region at far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth-century observers. Christiaan Huygens used this feature to measure the rotation rate of Mars. (A Martian day is about 24 hours and 37 minutes.) Today we know that Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view. A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact. The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute) #nasagoddard #mars #hubble #space NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics

Methane Seepage on Mars: Where to Look and Why

NASA Astrophysics Data System (ADS)

Oehler, Dorothy Z.; Etiope, Giuseppe

2017-12-01

Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available.

Mars Global Surveyor Approach Image

NASA Image and Video Library

1997-07-04

This image is the first view of Mars taken by the Mars Global Surveyor Orbiter Camera (MOC). It was acquired the afternoon of July 2, 1997 when the MGS spacecraft was 17.2 million kilometers (10.7 million miles) and 72 days from encounter. At this distance, the MOC's resolution is about 64 km per picture element, and the 6800 km (4200 mile) diameter planet is 105 pixels across. The observation was designed to show the Mars Pathfinder landing site at 19.4 N, 33.1 W approximately 48 hours prior to landing. The image shows the north polar cap of Mars at the top of the image, the dark feature Acidalia Planitia in the center with the brighter Chryse plain immediately beneath it, and the highland areas along the Martian equator including the canyons of the Valles Marineris (which are bright in this image owing to atmospheric dust). The dark features Terra Meridiani and Terra Sabaea can be seen at the 4 o`clock position, and the south polar hood (atmospheric fog and hazes) can be seen at the bottom of the image. Launched on November 7, 1996, Mars Global Surveyor will enter Mars orbit on Thursday, September 11 shortly after 6:00 PM PDT. After Mars Orbit Insertion, the spacecraft will use atmospheric drag to reduce the size of its orbit, achieving a circular orbit only 400 km (248 mi) above the surface in early March 1998, when mapping operations will begin. http://photojournal.jpl.nasa.gov/catalog/PIA00606

Hydrologic Modeling of Relatively Recent Martian Streams and Lake

NASA Image and Video Library

2016-09-15

This map of an area within the Arabia Terra region on Mars shows where hydrologic modeling predicts locations of depressions that would have been lakes (black), overlaid with a map of the preserved valleys (blue lines, with width exaggerated for recognition) that would have been streams. The area today holds numerous features called "fresh shallow valleys." Research findings in 2016 interpret the fresh shallow valleys as evidence for flows of liquid water that occurred several hundred million years -- up to about a billion years -- after the ancient lakes and streams previously documented on Mars. Most of the fresh shallow valleys in this northern portion of Arabia Terra terminate at the margins of model-predicted submerged basins, consistent with an interpretation of flows into lakes and out of lakes. Some valley segments connect to form longer systems, consistent with connections forged by flowing water between interspersed lakes. In the area mapped here, for example, valleys connect basin "A" to basin "B," and basin B to "Heart Lake," each lower in elevation in that chain. http://photojournal.jpl.nasa.gov/catalog/PIA20839

Methane Seepage on Mars: Where to Look and Why.

PubMed

Oehler, Dorothy Z; Etiope, Giuseppe

2017-12-01

Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available. Key

Investigating Mars: Moreux Crater

NASA Image and Video Library

2017-11-22

This image of Moreux Crater shows the western floor of the crater and the multitude of sand dunes that are found on the floor of the crater. A large sand sheet with surface dunes forms is located at the top of the image, and smaller individual dunes stretch from the bottom of the sand sheet to the bottom of the image. In this false color image sand dunes are "blue". Moreux Crater is located in northern Arabia Terra and has a diameter of 138 kilometers. The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 10384 Latitude: 41.841 Longitude: 44.087 Instrument: VIS Captured: 2004-04-17 10:07 https://photojournal.jpl.nasa.gov/catalog/PIA22035

Investigating Mars: Moreux Crater

NASA Image and Video Library

2017-11-23

This image of Moreux Crater shows the eastern side of the central peak, as well as the nearby sand dunes. In this false color image sand dunes are "blue". Smaller patches of blue are located on the central peak materials and indicate where surface winds have moved fine materials on/off the peak deposits. The pitted and curvilinear morphology of the central peak deposits have been interpreted to have formed by glacial activity. Moreux Crater is located in northern Arabia Terra and has a diameter of 138 kilometers. The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 12518 Latitude: 41.8223 Longitude: 44.7638 Instrument: VIS Captured: 2004-10-10 02:55 https://photojournal.jpl.nasa.gov/catalog/PIA22126

Investigating Mars: Moreux Crater

NASA Image and Video Library

2017-11-24

This image of Moreux Crater shows the highest elevations of the central peak, as well as the nearby sand dunes. In this false color image sand dunes are "blue". Smaller patches of blue are located on the central peak materials and indicate where surface winds have moved fine materials on/off the peak deposits. The pitted and curvilinear morphology of the central peak deposits have been interpreted to have formed by glacial activity. Moreux Crater is located in northern Arabia Terra and has a diameter of 138 kilometers. The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 46786 Latitude: 41.7667 Longitude: 44.3482 Instrument: VIS Captured: 2012-07-01 13:41 https://photojournal.jpl.nasa.gov/catalog/PIA22127

Rock Magnetic Fields Shield the Surface of Mars from Harmful Radiation

NASA Astrophysics Data System (ADS)

Alves, E. I.; Baptista, A. R.

2004-03-01

We intend to show that there is a negative correlation between areas of magnetic anomalies and areas of energetic particles bombardment on the surface of Mars, by comparing MGS MAG-ER and Mars Odyssey MARIE maps. Terra Sirenum is the most shielded area.

Mars 2020 Candidate Landing Site in McLaughlin Crater

NASA Image and Video Library

2016-01-14

McLaughlin Crater (21.9 N, 337.6 E) is a large, approximately 95-kilometer diameter impact crater located north of Mawrth Vallis, in Arabia Terra, a region that was made famous by the book and movie "The Martian" by Andy Weir. McLaughlin Crater straddles three major terrain types: the Northern lowlands, the Southern highlands and the Mawrth Vallis region. The crater floor is thought to be covered by clays and carbonates that were deposited in a deep lake at least 3.8 billion years ago perhaps by ground water upwelling from beneath the crater floor (Michalski et al., 2013, Nature Geoscience). McLaughlin Crater is listed as a candidate landing site for the 2020 Mars surface mission. Although it is described as a "flat, low-risk and low-elevation landing zone," the region in this image on the southern floor of the crater shows a complex surface of eroded layers that are rough in places. An unusual feature is a straight fracture cutting diagonally across the layered material at the bottom portion of the image that may be a fault line. http://photojournal.jpl.nasa.gov/catalog/PIA20338

Highest-Resolution View of 'Face on Mars'

NASA Technical Reports Server (NTRS)

2001-01-01

A key aspect of the Mars Global Surveyor (MGS) Extended Mission is the opportunity to turn the spacecraft and point the Mars Orbiter Camera (MOC) at specific features of interest. A chance to point the spacecraft comes about ten times a week. Throughout the Primary Mission (March 1999 - January 2001), nearly all MGS operations were conducted with the spacecraft pointing 'nadir'--that is, straight down. In this orientation, opportunities to hit a specific small feature of interest were in some cases rare, and in other cases non-existent. In April 1998, nearly a year before MGS reached its Primary Mission mapping orbit, several tests of the spacecraft's ability to be pointed at specific features was conducted with great success (e.g., Mars Pathfinder landing site, Viking 1 site, and Cydonia landforms). When the Mars Polar Lander was lost in December 1999, this capability was again employed to search for the missing lander. Following the lander search activities, a plan to conduct similar off-nadir observations during the MGS Extended Mission was put into place. The Extended Mission began February 1, 2001. On April 8, 2001, the first opportunity since April 1998 arose to turn the spacecraft and point the MOC at the popular 'Face on Mars' feature.

Viking orbiter images acquired in 1976 showed that one of thousands of buttes, mesas, ridges, and knobs in the transition zone between the cratered uplands of western Arabia Terra and the low, northern plains of Mars looked somewhat like a human face. The feature was subsequently popularized as a potential 'alien artifact' in books, tabloids, radio talk shows, television, and even a major motion picture. Given the popularity of this landform, a new high-resolution view was targeted by pointing the spacecraft off-nadir on April 8, 2001. On that date at 20:54 UTC (8:54 p.m., Greenwich time zone), the MGS was rolled 24.8o to the left so that it was looking at the 'face' 165 km to the side from a distance of about 450 km

Multi-agent gully processes: Evidence from the Monaro Volcanic Province, Australia and in Terra Cimmeria, Mars

NASA Astrophysics Data System (ADS)

Hobbs, S. W.; Paull, D. J.; Clarke, J. D. A.; Roach, Ian C.

2016-03-01

Comparison of the similarities and differences between terrestrial and Martian hillside gullies promotes understanding of how surface processes operate on both planets. Here we tested the viability of subsurface flow of water as a process affecting gully evolution. We compared gullies within the Monaro Volcanic Province near Cooma, New South Wales, Australia, to gullies possessing strong structural control near Gasa Crater, Terra Cimmeria, Mars. Although cursory examination of the Monaro gullies initially suggested strong evidence for aquifer erosion, detailed field surveys showed the evidence to be ambiguous. Instead a complex regime of erosion dependent on multiple conditions and processes such as local geology, surface runoff, dry mass wasting, and animal activity emerged. We found the morphology of gullies near Gasa Crater to be consistent with erosion caused by liquid water, while also being heavily influenced by the local environment, including slope and geology. Additionally, erosion at the Martian site was not consistent with evidence of subsequent, smaller scale erosion and channel modification by dry mass wasting. Local conditions thus play an important role in gully evolution, further highlighting that processes forming Martian gullies may be more diverse than initially thought.

Lunar and Planetary Science XXXV: Mars Geophysics

NASA Technical Reports Server (NTRS)

2004-01-01

The titles in this section include: 1) Distribution of Large Visible and Buried Impact Basins on Mars: Comparison with Free-Air Gravity, Crustal Thickness, and Magnetization Models; 2) The Early Thermal and Magnetic State of Terra Cimmeria, Southern Highlands of Mars; 3) Compatible Vector Components of the Magnetic Field of the Martian Crust; 4) Vertical Extrapolation of Mars Magnetic Potentials; 5) Rock Magnetic Fields Shield the Surface of Mars from Harmful Radiation; 6) Loading-induced Stresses near the Martian Hemispheric Dichotomy Boundary; 7) Growth of the Hemispheric Dichotomy and the Cessation of Plate Tectonics on Mars; 8) A Look at the Interior of Mars; 9) Uncertainties on Mars Interior Parameters Deduced from Orientation Parameters Using Different Radio-Links: Analytical Simulations; 10) Refinement of Phobos Ephemeris Using Mars Orbiter Laser Altimetry Radiometry.

Crustal Evolution of the Protonilus Mensae Area, Mars

NASA Technical Reports Server (NTRS)

McGill, G. E.; Smrekar, S. E.; Dimitriou, A. M.; Raymond, C. A.

2004-01-01

Despite research by numerous geologists and geo- physicists, the age and origin of the martian crustal dichotomy remain uncertain. Models for the origin of this dichotomy involve single or multiple impact, mantle megaplumes, primordial crustal asymmetry, and plate tectonics. Most of these models imply a Noachian age for the dichotomy. A major problem common to all genetic models is the difficulty separating the features resulting from the primary cause for the dichotomy from features due to younger fault- ing, impact cratering, volcanism, deposition, and erosion. highlands (the dichotomy boundary) approximates a small circle that ranges in latitude from about -10 deg. in Elysium Planitia to about +45 deg. north of Arabia Terra. For much of its length the boundary is characterized by relatively steep scarps separating highland plateau to the south from lowland plains to the north, generally with a complex transition zone on the lowland side of these scarps. These scarps are almost certainly due to normal faulting. The type fretted terrain, which defines the boundary in north-central Arabia Terra, also is characterized by scarps but has under- gone a more complex history of faulting and dissection [13]. In some places, notably in the Acidalia Planitia region, the dichotomy boundary is gradational. In the Tharsis region the boundary is obscured by younger volcanics.

Lunar and Planetary Science XXXV: Martian Aeolian and Mass Wasting Processes: Blowing and Flowing

NASA Technical Reports Server (NTRS)

2004-01-01

The session Martian Aeolian and Mass Wasting Processes: BLowing and Flowing included the following topics: 1) Three Decades of Martian Surface Changes; 2) Thermophysical Properties of Isidis Basin, Mars; 3) Intracrater Material in Eastern Arabia Terra: THEMIS, MOC, and MOLA Analysis of Wind-blown Deposits and Possible High-Inertia Source Material; 4) Thermal Properties of Sand from TES and THEMIS: Do Martian Dunes Make a Good Control for Thermal Inertia Calculations? 5) A Comparative Analysis of Barchan Dunes in the Intra-Crater Dune Fields and the North Polar Sand Sea; 6) Diluvial Dunes in Athabasca Valles, Mars: Morphology, Modeling and Implications; 7) Surface Profiling of Natural Dust Devils; 8) Martian Dust Devil Tracks: Inferred Directions of Movement; 9) Numerical Simulations of Anastomosing Slope Streaks on Mars; 10) Young Fans in an Equatorial Crater in Xanthe Terra, Mars; 11) Large Well-exposed Alluvual Fans in Deep Late-Noachian Craters; 12) New Evidence for the Formation of Large Landslides on Mars; and 13) What Can We Learn from the Ages of Valles Marineris Landslides on Martian Impact History?

Relative Ages of the Highlands, Lowlands, and Transition Zone Along a Portion of the Mars Crustal Dichotomy from Densities of Visible and Buried Impact Craters

NASA Technical Reports Server (NTRS)

DeSoto, G. E.; Frey, H. V.

2005-01-01

Understanding the fundamental age relationships of the different parts of the Mars Crustal Dichotomy is essential to fully understanding the events that shaped the early history and formation of the surface of Mars. A dominant question is what are the true relative ages of the Northern Lowlands and the Southern Highlands? Using MOLA data from the Mars Global Surveyor and Viking visual images, a dataset of both buried and visible crater diameters was created over a nine million sq km study area of a section of the dichotomy boundary stretching from Arabia Terra to Utopia Planitia. Cumulative frequency plots on a log-log scale were used to determine the relative ages for the Highlands, the Lowlands, and the Transition Zone, separately for the visible, the buried and the combined total (visible+ buried) populations. We find the overall Highland crater population in this area is slightly older than the Lowlands, consistent with previous global studies, but the Lowlands and Transition Zone are also very old and formed at roughly the same time. It appears that the formation of the Lowlands in this region formed contemporaneously with a large-scale resurfacing event in the Highlands, perhaps caused by the process responsible for the Lowland formation.

A New Gully Channel in Terra Sirenum, Mars

NASA Image and Video Library

2014-03-19

This pair of before left and after right images from NASA Mars Reconnaissance Orbiter documents formation of a new channel on a Martian slope between 2010 and 2013, likely resulting from activity of carbon-dioxide frost.

Methane Seepage on Mars: Where to Look and Why

PubMed Central

Etiope, Giuseppe

2017-01-01

Abstract Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as “gas seepage.” Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently

Detection and context of hydrated mineralogy in the Tyrrhena Terra region, Mars

NASA Astrophysics Data System (ADS)

den Haan, J.; Zegers, T. E.; van Ruitenbeek, F. J. A.; van der Werff, H. M. A.; Rossi, A.

2008-09-01

Introduction The discovery of phyllosilicates on Mars [1] has had major implications on the perceived geologic and climatologic evolution of Mars [2]. Not only do phyllosilicates represent a `wet' period on Mars, they might also represent a potentially favorable environment for life. The phyllosilicates have so far exclusively been found in or close to ancient Noachian highland terrain. Those phyllosilicate deposits studied (e.g. [3]) show a clear association between hydrated mineralogy and heavily eroded and crater-saturated outcrops. Phyllosilicates on Earth are associated with a wide variety of geological processes (volcanism, metamorphism, hydrothermal alteration, sedimentation). The occurrence of phyllosilicates on Mars may be equally diverse in nature. To be able to place constraints on the early Martian environment, the processes by which these phyllosilicates formed need to be reconstructed. To derive this information from individual phyllosilicate deposits, it is necessary to interpret their composition in relation to their geological context and relative time relationships. We conducted such an integrated hyperspectral and geological study of the Tyrrhena Terra region. Data products ad methods HRSC data products (both image at 12 m/pixel and stereo-derived DTMs) are used for examining geologic cross-cutting relationships, geomorphologic landforms and visual determination of unit boundaries. Odyssey THEMIS nighttime TIR images are analyzed for spatial variations in thermal inertia. Where available, HRSC is supplemented by higher-resolution visible observations of CTX or MOC. Hyperspectral analysis is conducted using data from the OMEGA hyperspectral instrument. In order to batch-process large amounts of OMEGA data, an IDL/ENVI tool was developed on top of the existing SOFT04, distributed by PSA. The applied atmospheric correction assumes that atmospheric contributions are multiplicative, and follow a power-law distribution with altitude [4]. The ratio of

Geologic Mapping of the Nili Fossae Region of Mars: MTM Quadrangles 20287, 20282, 25287, 25282, 30287, and 30282

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III; Crown, David A.

2010-01-01

Geologic mapping studies at the 1:1M-scale are being used to assess geologic materials and processes that shape the highlands along the Arabia Terra dichotomy boundary. In particular, this mapping will provide a regional context and evaluate the distribution, stratigraphic position, and potential lateral continuity of compositionally distinct outcrops identified by spectral instruments currently in orbit (i.e., CRISM and OMEGA). Placing these landscapes, their material units, structural features, and unique compositional outcrops into spatial and temporal context with the remainder of the Arabia Terra dichotomy boundary may provide constraints on: 1) origin of the dichotomy boundary, 2) paleoenvironments and climate conditions, and 3) various fluvial-nival modification processes related to past and present volatile distribution and their putative reservoirs (aquifers, lakes and oceans, surface and ground ice) and the influences of nearby volcanic and tectonic features on hydrologic processes, including hydrothermal alteration, across the region.

Peleolakes and impact basins in southern Arabia Terra, including Meridiani Planum: Implications for the formation of hematite deposits on Mars

USGS Publications Warehouse

Newsom, Horton E.; Barber, C.A.; Hare, T.M.; Schelble, R.T.; Sutherland, V.A.; Feldman, W.C.

2003-01-01

The hematite deposit in Meridiani Planum was selected for a Mars Exploration Rover (MER) landing site because water could be involved in the formation of hematite, and water is a key ingredient in the search for life. Our discovery of a chain of paleolake basins and channels along the southern margin of the hematite deposits in Meridiani Planum with the presence of the strongest hematite signature adjacent to a paleolake basin, supports the possible role of water in the formation of the hematite and the deposition of other layered materials in the region. The hematite may have formed by direct precipitation from lake water, as coatings precipitated from groundwater, or by oxidation of preexisting iron oxide minerals. The paleolake basins were fed by an extensive channel system, originating from an area larger than Texas and located south of the Schiaparelli impact basin. On the basis of stratigraphic relationships, the formation of channels in the region occurred over much of Mars' history, from before the layered materials in Meridiani Planum were deposited until recently. The location of the paleolake basins and channels is connected with the impact cratering history of the region. The earliest structure identified in this study is an ancient circular multiringed basin (800-1600 km diameter) that underlies the entire Meridiani Planum region. The MER landing site is located on the buried northern rim of a later 150 km diameter crater. This crater is partially filled with layered deposits that contained a paleolake in its southern portion. Copyright 2003 by the American Geophysical Union.

Ishtar Terra

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

One of the three large upland regions of Venus (the other two being Aphrodite Terra and Lada Terra), situated in the planet's northern hemisphere and centered at 70.4 °N, 27.5 °E. In its greatest dimension it measures 5609 km. It takes its name from a Babylonian goddess of love. The western end of Ishtar Terra is dominated by the pear-shaped volcanic plateau Lakshmi Planum, 2343 km across. The pl...

Lada Terra

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

One of the three large upland regions of Venus (the other two being Aphrodite Terra and Ishtar Terra), situated in the planet's southern hemisphere and centered at 54.4 °S, 17.5 °W. In its greatest dimension it measures 8614 km. It takes its name from a Slavic goddess of love. Like the other upland regions, Lada Terra is covered with tesserae: criss-crossing troughs and ridges. Lada is less eleva...

Terra Meridiani

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site] (Released 28 June 2002) The Science This THEMIS visible image illustrates the complex terrains within Terra Meridiani. This general region is one of the more complex on Mars, with a rich array of sedimentary, volcanic, and impact surfaces that span a wide range of martian history. This image lies at the eastern edge of a unique geologic unit that was discovered by the Mars Global Surveyor Thermal Emission Spectrometer (TES) Science Team to have high concentrations of a unique mineral called grey (crystalline) hematite. As discussed by the TES Science Team, this mineral typically forms by processes associated with water, and this region appears to have undergone alteration by hydrothermal (hot water) or other water-related processes. As a result of this evidence for water activity, this region is a leading candidate for further exploration by one of NASA's upcoming Mars Exploration Rovers. The brightness and texture of the surface varies remarkably throughout this image. These differences are associated with different rock layers or ?units?, and can be used to map the occurrence of these layers. The number of layers indicates that extensive deposition by volcanic and sedimentary processes has occurred in this region. Since that time, however, extensive erosion has occurred to produce the patchwork of different layers exposed across the surface. Several distinct layers can be seen within the 20 km diameter crater at the bottom (south) of the image, indicating that this crater once contained layers of sedimentary material that has since been removed. THEMIS infrared images of this region show that many of these rock layers have distinctly different temperatures, indicating that the physical properties vary from layer to layer. These differences suggest that the environment and the conditions under which these layers were deposited or solidified varied through time as these layers were formed. The Story Mars exploration

Monitoring on Xi'an ground fissures deformation with TerraSAR-X data

USGS Publications Warehouse

Zhao, C.; Zhang, Q.; Zhu, W.; Lu, Z.

2012-01-01

Owing to the fine resolution of TerraSAR-X data provided since 2007, this paper applied 6 TerraSAR data (strip mode) during 3rd Dec. 2009 to 23rd Mar. 2010 to detect and monitor the active fissures over Xi'an region. Three themes have been designed for high precision detection and monitoring of Xi'an-Chang'an fissures, as small baseline subsets (SBAS) to test the atmospheric effects of differential interferograms pair stepwise, 2-pass differential interferogram with very short baseline perpendicular to generate the whole deformation map with 44 days interval, and finally, corner reflector (CR) technique was used to closely monitor the relative deformation time series between two CRs settled crossing two ground fissures. Results showed that TerraSAR data are a good choice for small-scale ground fissures detection and monitoring, while special considerations should be taken for their great temporal and baseline decorrelation. Secondly, ground fissures in Xi'an were mostly detected at the joint section of stable and deformable regions. Lastly, CR-InSAR had potential ability to monitor relative deformation crossing fissures with millimeter precision.

Intimations of water on Mars.

PubMed

2000-08-01

This photo essay contains images of Mars that propose evidence of the possible present or past existence of liquid water on Mars. Images were taken by the Mars Global Surveyor Mars Orbiter Camera. Images presented include: Polar Wall Pit region, consisting of gully landforms possibly caused by seepage and runoff of liquid water; Noachis Terra region, an area of gullies eroded into the wall of a meteor impact crater, where channels and related debris are seen, possibly formed by seepage, runoff, and debris flow; two images of Gorgonum Chaos region, one a series of troughs and layers of gullies and the other of gullies in a specific layer forming an alcove similar to an aquifer; Sirenum Fossae/Gorgonum Chaos mosaic of two images from this region of the southern hemisphere of Mars, showing 20 different channels coming down from a trough and their associated debris fans. Images and their enhancements are from NASA/JPL/Malin Space Science System.

Topographic Change of the Dichotomy Boundary Suggested by Crustal Inversion

NASA Technical Reports Server (NTRS)

Neumann, G. A.

2004-01-01

Linear negative gravity anomalies in Acidalia Planitia along the eastern edge of Tempe Terra and along the northern edge of Arabia Terra have been noted in Mars Global Surveyor gravity fields. Once proposed to represent buried fluvial channels, it is now believed that these gravity troughs mainly arise from partial compensation of the hemispheric dichotomy topographic scarp. A recent inversion for crustal structure finds that mantle compensation of the scarp is offset from the present-day topographic expression of the dichotomy boundary. The offset suggests that erosion or other forms of mass wasting occurred after lithosphere thickened and no longer accomodated topographic change through viscous relaxation.

EOS Terra Terra Constellation Exit/Future Maneuver Plans Update

NASA Technical Reports Server (NTRS)

Mantziaras, Dimitrios

2016-01-01

This EOS Terra Constellation Exit/Future Maneuver Plans Update presentation will discuss brief history of Terra EOM work; lifetime fuel estimates; baseline vs. proposed plan origin; resultant exit orbit; baseline vs. proposed exit plan; long term orbit altitude; revised lifetime proposal and fallback options.

Terra Cimmeria Crater Landslide

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

The landslide in this VIS image is located inside an impact crater in the Terra Cimmeria region of Mars. The unnamed crater hosting this image is just east of Molesworth Crater.

Image information: VIS instrument. Latitude -27.7, Longitude 152 East (208 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Fretted Terrain Valleys

NASA Technical Reports Server (NTRS)

2004-01-01

30 October 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows shallow tributary valleys in the Ismenius Lacus fretted terrain region of northern Arabia Terra. These valleys exhibit a variety of typical fretted terrain valley wall and floor textures, including a lineated, pitted material somewhat reminiscent of the surface of a brain. Origins for these features are still being debated within the Mars science community; there are no clear analogs to these landforms on Earth. This image is located near 39.9oN, 332.1oW. The picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

Tectonic implications of Mars crustal magnetism

PubMed Central

Connerney, J. E. P.; Acuña, M. H.; Ness, N. F.; Kletetschka, G.; Mitchell, D. L.; Lin, R. P.; Reme, H.

2005-01-01

Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization, presumably by cooling in the presence of an Earth-like magnetic field (thermoremanent magnetization). A new map of the magnetic field of Mars, compiled by using measurements acquired at an ≈400-km mapping altitude by the Mars Global Surveyor spacecraft, is presented here. The increased spatial resolution and sensitivity of this map provide new insight into the origin and evolution of the Mars crust. Variations in the crustal magnetic field appear in association with major faults, some previously identified in imagery and topography (Cerberus Rupes and Valles Marineris). Two parallel great faults are identified in Terra Meridiani by offset magnetic field contours. They appear similar to transform faults that occur in oceanic crust on Earth, and support the notion that the Mars crust formed during an early era of plate tectonics. PMID:16217034

Tectonic implications of Mars crustal magnetism.

PubMed

Connerney, J E P; Acuña, M H; Ness, N F; Kletetschka, G; Mitchell, D L; Lin, R P; Reme, H

2005-10-18

Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization, presumably by cooling in the presence of an Earth-like magnetic field (thermoremanent magnetization). A new map of the magnetic field of Mars, compiled by using measurements acquired at an approximately 400-km mapping altitude by the Mars Global Surveyor spacecraft, is presented here. The increased spatial resolution and sensitivity of this map provide new insight into the origin and evolution of the Mars crust. Variations in the crustal magnetic field appear in association with major faults, some previously identified in imagery and topography (Cerberus Rupes and Valles Marineris). Two parallel great faults are identified in Terra Meridiani by offset magnetic field contours. They appear similar to transform faults that occur in oceanic crust on Earth, and support the notion that the Mars crust formed during an early era of plate tectonics.

The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

NASA Technical Reports Server (NTRS)

Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

2014-01-01

We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

Partially-Exhumed Crater in Northern Terra Meridiani: Stereo Anaglyph of overlapping coverage in

NASA Technical Reports Server (NTRS)

2002-01-01

MGS MOC Release No. MOC2-316, 8 August 2002 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images have shown time and again that the geology and history of Mars is complex. These two pictures show different views of a circular feature in northern Terra Meridiani at 2.3oN, 356.6oW. The first is a mosaic of 3 MOC narrow angle images acquired in August 1999, November 2000, and June 2002. The black area is a gap in coverage resulting from data lost after transmission from Mars to Earth. The second picture is a stereo ('3-D') anaglyph of a portion of the same circular feature. It has been rotated 90o clockwise to show the stereo effect that results from combining the August 1999 image, which was taken while the spacecraft was pointed nadir (straight down) and the June 2002 image, taken with the spacecraft pointing backwards about 16o (i.e., MGS Relay-16 orientation). The anaglyph should be viewed with '3-D' glasses (red in left eye, blue in the right). The circular feature was once an impact crater. The crater was 2.6 km (1.6 mi) across, about 2.6 times larger than the famous Meteor Crater in northern Arizona. Terra Meridiani, like northern Arizona, is a region of vast exposures of layered sedimentary rock. Like the crater in Arizona, this one was formed by a meteor that impacted a layered rock substrate. Later, this crater was filled and completely buried under more than 100 m (more than 327 ft) of additional layered sediment. The sediment hardened to become rock. Later still, the rock was eroded away--by processes unknown (perhaps wind)--to re-expose the buried crater. The crater today remains mostly filled with sediment, its present rim standing only about 40 m (130 ft) above its surroundings.

Abstracts of the Annual Meeting of Planetary Geologic Mappers, San Antonio, TX, 2009

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L.; Kelley, Michael S.

2009-01-01

Topics covered include: Geologic Mapping of the Beta-Atla-Themis (BAT) Region of Venus: A Progress Report; Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for Tectonic and Volcanic History of the North Polar Region of Venus; Preliminary Geological Map of the Fortuna Tessera (V-2) Quadrangle, Venus; Geological Map of the Fredegonde (V-57) Quadrangle, Venus; Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus; Geologic Mapping of V-19; Lunar Geologic Mapping: A Preliminary Map of a Portion of the LQ-10 ("Marius") Quadrangle; Geologic Mapping of the Lunar South Pole, Quadrangle LQ-30: Volcanic History and Stratigraphy of Schr dinger Basin; Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars; Geologic Mapping Investigations of the Northwest Rim of Hellas Basin, Mars; Geologic Mapping of the Meridiani Region of Mars; Geology of a Portion of the Martian Highlands: MTMs -20002, -20007, -25002 and -25007; Geologic Mapping of Holden Crater and the Uzboi-Ladon-Morava Outflow System; Mapping Tyrrhena Patera and Hesperia Planum, Mars; Geologic Mapping of Athabaca Valles; Geologic Mapping of MTM -30247, -35247 and -40247 Quadrangles, Reull Vallis Region, Mars Topography of the Martian Impact Crater Tooting; Mars Structural and Stratigraphic Mapping along the Coprates Rise; Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: Project Introduction and First Year Work Plan; Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: Second Year Results and Third Year Plan; Mars Global Geologic Mapping: About Half Way Done; New Geologic Map of the Scandia Region of Mars; Geologic Mapping of the Medusae Fossae Formation on Mars and the Northern Lowland Plains of Venus; Volcanism on Io: Insights from Global Geologic Mapping; and Planetary Geologic Mapping Handbook - 2009.

Major water-related episodes on the lowlands of Mars

NASA Astrophysics Data System (ADS)

Fairén, A. G.; Dohm, J. M.; Baker, V. R.

2003-04-01

in Arabia Terra, where the initial shoreline might have been as far south as Sinus Meridani (Edgett and Parker, 1997), forming an almost equipotential line (total elevation differences are ˜2 km) that we name Contact 0, which is also consistent with the location of the boundary in crustal thickness dichotomy, as deduced from topography and gravity data (Zuber et al., 2000), and with the locus of debouch of almost every valley network in Arabia (Edgett and Parker, 1997; Carr, 2002); a Late Hesperian sea, which would have extended over the deeper areas in the lowlands inset within the boundary of the first great ocean, and so portrayed by Contact 2; and a number of widely distributed minor lakes that may represent a reduced Late Hesperian sea, or ponded waters in the deepest reaches of the northern plains related to minor Tharsis (e.g., Anderson et al., 2001) and Elysium (Skinner and Tanaka, 2001) induced Amazonian flooding. Possible biologic evolution throughout the resulting different climatic and hydrologic conditions would account for very distinct metabolic pathways for hypothesized organisms capable of surviving and perhaps evolving in each aqueous environment, those that existed in the dry and cold periods between the flood inundations, and those organisms that could survive both extremes. Terrestrial microbiota, chemolithotrophic and heterotrophic bacteria, provide exciting analogues for such potential extremophile existence in Mars, especially where long-lived, magmatic-driven hydrothermal activity is indicated (Farmer and Des Marais, 1999). Such Martian environments and related materials and life forms may have been excavated to the surface by catastrophic outflows making targets readily available for sampling and in-deep analyses. References Anderson, R. C. et al.: Primary centers and secondary concentrations of tectonic activity through time in western hemisphere of Mars. J. Geophys. Res. 106, 20 563--20 585, 2001. Baker, V.R., et al.: Ancient oceans, ice

First Self-Consistent, Two-Layer Model of Near-Surface Water-Equivalent-Hydrogen on Mars

NASA Astrophysics Data System (ADS)

Feldman, W. C.; Pathare, A.; Prettyman, T. H.; Maurice, S.

2015-12-01

This study uses 9.5 years of Mars Odyssey Neutron Spectrometer (MONS) data [1]. We have used the epithermal and fast neutron count rates to determine the water-equivalent-hydrogen (WEH) content of an upper layer, Wup, having thickness D. The "crossover" technique we utilized is an improvement over previous work [2,3]. We then used Monte Carlo simulated grids of epithermal and thermal count rates spanning Wup = 1% to 15% [4] to determine the WEH content, Wdn, of a semi-infinite lower layer buried at depth, D. We also advance upon previous work by using improved deconvolution methods to reduce spatial blurring in fast and epithermal maps [5]. The resultant count-rates were digitized into a 2°x2°cylindrical grid for all WEH computations. Two sets of WEH maps will be shown. The first uses the one-layer model developed initially by Feldman et al. [6]. Comparison of the undeconvolved and deconvolved versions clearly illustrates the improvement obtained by deconvolution. We will also present the full two layer maps of Wup, Wdn, and D for the deconvolved data sets, which show: 1) contrary to our previous preliminary mapping [3], the fresh icy mid-latitude craters identified by [7] are NOT exclusively found in regions with average Wdn values that exceed the pore-filling threshold for regolith ice; 2) a maximum Wdn of about 80% by weight at the Phoenix site; 3) an isolated Wdn maximum just east of Gale crater that is centered on Aeolis Mensae; 4) a resolved Wdn maximum that overlays the Orsen Wells crater on Xanthe Terra; 5) Wdn local maxima that hug the western flanks of Olympus Mons and Elysium Mons, and 6) several Wdn maxima that cover Arabia Terra. We will present and interpret regional maps of all of these features. Refs: [1] Maurice et al. JGR, 2011; [2] Feldman et al. JGR, 2011; [3] Pathare et al. 8th Mars Conf., 2014; [4] Prettyman et al. JGR, 2004 [5] Prettyman et al. JGR, 2009; [6] Feldman et al. JGR, 2004; [7] Dundas et al. JGR, 2014.

Thermal Inertia, Albedo, and MOLA-derived Roughness for Terrains in the Terra Meridiani Area, Mars

NASA Technical Reports Server (NTRS)

Arvidson, R. E.; Deal, K.; Hynek, B. M.; Seelos, F. P., IV; Snider, N. O.; Mellon, M. T.; Garvin, J. B.

2002-01-01

Surface properties of layered deposits draped on dissected, cratered terrain in the Terra Meridiani area are analyzed using remote sensing data. The etched plains are cemented and differentially eroded, and the hematite plains are loose and drifting. Additional information is contained in the original extended abstract.

DEMONSTRATION BULLETIN: TERRA KLEEN SOLVENT EXTRACTION TECHNOLOGY - TERRA-KLEEN RESPONSE GROUP, INC.

EPA Science Inventory

The Terra-Kleen Solvent Extraction Technology was developed by Terra-Kleen Response Group, Inc., to remove polychlorinated biphenyls (PCB) and other organic constituents from contaminated soil. This batch process system uses a proprietary solvent at ambient temperatures to treat ...

Mineralogical, chemical, organic and microbial properties of subsurface soil cores from Mars Desert Research Station (Utah, USA): Phyllosilicate and sulfate analogues to Mars mission landing sites

NASA Astrophysics Data System (ADS)

Stoker, Carol R.; Clarke, Jonathan; Direito, Susana O. L.; Blake, David; Martin, Kevin R.; Zavaleta, Jhony; Foing, Bernard

2011-07-01

We collected and analysed soil cores from four geologic units surrounding Mars Desert Research Station (MDRS) Utah, USA, including Mancos Shale, Dakota Sandstone, Morrison formation (Brushy Basin member) and Summerville formation. The area is an important geochemical and morphological analogue to terrains on Mars. Soils were analysed for mineralogy by a Terra X-ray diffractometer (XRD), a field version of the CheMin instrument on the Mars Science Laboratory (MSL) mission (2012 landing). Soluble ion chemistry, total organic content and identity and distribution of microbial populations were also determined. The Terra data reveal that Mancos and Morrison soils are rich in phyllosilicates similar to those observed on Mars from orbital measurements (montmorillonite, nontronite and illite). Evaporite minerals observed include gypsum, thenardite, polyhalite and calcite. Soil chemical analysis shows sulfate the dominant anion in all soils and SO4>>CO3, as on Mars. The cation pattern Na>Ca>Mg is seen in all soils except for the Summerville where Ca>Na. In all soils, SO4 correlates with Na, suggesting sodium sulfates are the dominant phase. Oxidizable organics are low in all soils and range from a high of 0.7% in the Mancos samples to undetectable at a detection limit of 0.1% in the Morrison soils. Minerals rich in chromium and vanadium were identified in Morrison soils that result from diagenetic replacement of organic compounds. Depositional environment, geologic history and mineralogy all affect the ability to preserve and detect organic compounds. Subsurface biosphere populations were revealed to contain organisms from all three domains (Archaea, Bacteria and Eukarya) with cell density between 3.0×106 and 1.8×107 cells ml-1 at the deepest depth. These measurements are analogous to data that could be obtained on future robotic or human Mars missions and results are relevant to the MSL mission that will investigate phyllosilicates on Mars.

Mars Ice Age, Simulated

NASA Technical Reports Server (NTRS)

2003-01-01

December 17, 2003

This simulated view shows Mars as it might have appeared during the height of a possible ice age in geologically recent time.

Of all Solar System planets, Mars has the climate most like that of Earth. Both are sensitive to small changes in orbit and tilt. During a period about 2.1 million to 400,000 years ago, increased tilt of Mars' rotational axis caused increased solar heating at the poles. A new study using observations from NASA's Mars Global Surveyor and Mars Odyssey orbiters concludes that this polar warming caused mobilization of water vapor and dust into the atmosphere, and buildup of a surface deposit of ice and dust down to about 30 degrees latitude in both hemispheres. That is the equivalent of the southern Unites States or Saudi Arabia on Earth. Mars has been in an interglacial period characterized by less axial tilt for about the last 300,000 years. The ice-rich surface deposit has been degrading in the latitude zone of 30 degrees to 60 degrees as water-ice returns to the poles.

In this illustration prepared for the December 18, 2003, cover of the journal Nature, the simulated surface deposit is superposed on a topography map based on altitude measurements by Global Surveyor and images from NASA's Viking orbiters of the 1970s.

Mars Global Surveyor and Mars Odyssey are managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, for the NASA Office of Space Science, Washington.

EOS Terra Validation Program

NASA Technical Reports Server (NTRS)

Starr, David

1999-01-01

The EOS Terra mission will be launched in July 1999. This mission has great relevance to the atmospheric radiation community and global change issues. Terra instruments include ASTER, CERES, MISR, MODIS and MOPITT. In addition to the fundamental radiance data sets, numerous global science data products will be generated, including various Earth radiation budget, cloud and aerosol parameters, as well as land surface, terrestrial ecology, ocean color, and atmospheric chemistry parameters. Significant investments have been made in on-board calibration to ensure the quality of the radiance observations. A key component of the Terra mission is the validation of the science data products. This is essential for a mission focused on global change issues and the underlying processes. The Terra algorithms have been subject to extensive pre-launch testing with field data whenever possible. Intensive efforts will be made to validate the Terra data products after launch. These include validation of instrument calibration (vicarious calibration) experiments, instrument and cross-platform comparisons, routine collection of high quality correlative data from ground-based networks, such as AERONET, and intensive sites, such as the SGP ARM site, as well as a variety field experiments, cruises, etc. Airborne simulator instruments have been developed for the field experiment and underflight activities including the MODIS Airborne Simulator (MAS), AirMISR, MASTER (MODIS-ASTER), and MOPITT-A. All are integrated on the NASA ER-2, though low altitude platforms are more typically used for MASTER. MATR is an additional sensor used for MOPITT algorithm development and validation. The intensive validation activities planned for the first year of the Terra mission will be described with emphasis on derived geophysical parameters of most relevance to the atmospheric radiation community. Detailed information about the EOS Terra validation Program can be found on the EOS Validation program

Related magma-ice interactions: Possible origins of chasmata, chaos, and surface materials in Xanthe, Margaritifer, Meridiani Terrae, Mars

USGS Publications Warehouse

Chapman, M.G.; Tanaka, K.L.

2002-01-01

We examine here the close spatial and temporal associations among several unique features of Xanthe and Margaritifer Terrae, specifically the Valles Marineris troughs or chasmata and their interior deposits, chaotic terrain, the circum-Chryse outflow channels, and the subdued cratered material that covers Xanthe, Margaritifer, and Meridiani Terrae. Though previous hypotheses have attempted to explain the origin of individual features or subsets of these, we suggest that they may all be related. All of these features taken together present a consistent scenario that includes the processes of sub-ice volcanism and other magma/ice interactions, results of intrusive events during Late Noachian to Early Amazonian times. ?? 2002 Elsevier Science (USA).

Driven by excess? Climatic implications of new global mapping of near-surface water-equivalent hydrogen on Mars

NASA Astrophysics Data System (ADS)

Pathare, Asmin V.; Feldman, William C.; Prettyman, Thomas H.; Maurice, Sylvestre

2018-02-01

We present improved Mars Odyssey Neutron Spectrometer (MONS) maps of near-surface Water-Equivalent Hydrogen (WEH) on Mars that have intriguing implications for the global distribution of "excess" ice, which occurs when the mass fraction of water ice exceeds the threshold amount needed to saturate the pore volume in normal soils. We have refined the crossover technique of Feldman et al. (2011) by using spatial deconvolution and Gaussian weighting to create the first globally self-consistent map of WEH. At low latitudes, our new maps indicate that WEH exceeds 15% in several near-equatorial regions, such as Arabia Terra, which has important implications for the types of hydrated minerals present at low latitudes. At high latitudes, we demonstrate that the disparate MONS and Phoenix Robotic Arm (RA) observations of near surface WEH can be reconciled by a three-layer model incorporating dry soil over fully saturated pore ice over pure excess ice: such a three-layer model can also potentially explain the strong anticorrelation of subsurface ice content and ice table depth observed at high latitudes. At moderate latitudes, we show that the distribution of recently formed impact craters is also consistent with our latest MONS results, as both the shallowest ice-exposing crater and deepest non-ice-exposing crater at each impact site are in good agreement with our predictions of near-surface WEH. Overall, we find that our new mapping is consistent with the widespread presence at mid-to-high Martian latitudes of recently deposited shallow excess ice reservoirs that are not yet in equilibrium with the atmosphere.

Geology and mineralogy of the Auki Crater, Tyrrhena Terra, Mars: A possible post impact-induced hydrothermal system

NASA Astrophysics Data System (ADS)

Carrozzo, F. G.; Di Achille, G.; Salese, F.; Altieri, F.; Bellucci, G.

2017-01-01

A variety of hydrothermal environments have been documented in terrestrial impact structures. Due to both past water interactions and meteoritic bombardment on the surface of Mars, several authors have predicted various scenarios that include the formation of hydrothermal systems. Geological and mineralogical evidence of past hydrothermal activity have only recently been found on Mars. Here, we present a geological and mineralogical study of the Auki Crater using the spectral and visible imagery data acquired by the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars), CTX (Context Camera) and HiRISE (High Resolution Imaging Science Experiment) instruments on board the NASA MRO mission. The Auki Crater is a complex crater that is ∼38 km in diameter located in Tyrrhena Terra (96.8°E and 15.7°S) and shows a correlation between its mineralogy and morphology. The presence of minerals, such as smectite, silica, zeolite, serpentine, carbonate and chlorite, associated with morphological structures, such as mounds, polygonal terrains, fractures and veins, suggests that the Auki Crater may have hosted a post impact-induced hydrothermal system. Although the distribution of hydrated minerals in and around the central uplift and the stratigraphic relationships of some morphological units could also be explained by the excavation and exhumation of carbonate-rich bedrock units as a consequence of crater formation, we favor the hypothesis of impact-induced hydrothermal circulation within fractures and subsequent mineral deposition. The hydrothermal system could have been active for a relatively long period of time after the impact, thus producing a potential transient habitable environment. It must be a spectrally neutral component to emphasize the spectral features; It is an average of spectra taken in the same column of the numerator spectra to correct the residual instrument artifacts and reduce detector noise that changes from column to column

Mars Digital Image Mosaic Globe

NASA Technical Reports Server (NTRS)

2000-01-01

The photomosaic that forms the base for this globe was created by merging two global digital image models (DIM's) of Mars-a medium-resolution monochrome mosaic processed to emphasize topographic features and a lower resolution color mosaic emphasizing color and albedo variations.

The medium-resolution (1/256 or roughly 231 m/pixel) monochromatic image model was constructed from about 6,000 images having resolutions of 150-350 m/pixel and oblique illumination (Sun 20 o -45 o above the horizon). Radiometric processing was intended to suppress or remove the effects of albedo variations through the use of a high-pass divide filter, followed by photometric normalization so that the contrast of a given topographic slope would be approximately the same in all images.

The global color mosaic was assembled at 1/64 or roughly 864 m/pixel from about 1,000 red- and green-filter images having 500-1,000 m/pixel resolution. These images were first mosaiced in groups, each taken on a single orbit of the Viking spacecraft. The orbit mosaics were then processed to remove spatially and temporally varying atmospheric haze in the overlap regions. After haze removal, the per-orbit mosaics were photometrically normalized to equalize the contrast of albedo features and mosaiced together with cosmetic seam removal. The medium-resolution DIM was used for geometric control of this color mosaic. A green-filter image was synthesized by weighted averaging of the red- and violet-filter mosaics. Finally, the product seen here was obtained by multiplying each color image by the medium-resolution monochrome image. The color balance selected for images in this map series was designed to be close to natural color for brighter, redder regions, such as Arabia Terra and the Tharsis region, but the data have been stretched so that the relatively dark regions appear darker and less red than they actually are.

The images are presented in a projection that portrays the entire surface of Mars in a

Search for Chemically Bound Water in the Surface Layer of Mars Based on HEND/Mars Odyssey Data

NASA Technical Reports Server (NTRS)

Basilevsky, A. T.; Litvak, M. L.; Mitrofanov, I. G.; Boynton, W.; Saunders, R. S.

2003-01-01

This study is emphasized on search for signatures of chemically bound water in surface layer of Mars based on data acquired by High Energy Neutron Detector (HEND) which is part of the Mars Odyssey Gamma Ray Spectrometer (GRS). Fluxes of epithermal (probe the upper 1-2 m) and fast (the upper 20-30 cm) neutrons, considered in this work, were measured since mid February till mid June 2002. First analysis of this data set with emphasis of chemically bound water was made. Early publications of the GRS results reported low neutron flux at high latitudes, interpreted as signature of ground water ice, and in two low latitude areas: Arabia and SW of Olympus Mons (SWOM), interpreted as 'geographic variations in the amount of chemically and/or physically bound H2O and or OH...'. It is clear that surface materials of Mars do contain chemically bound water, but its amounts are poorly known and its geographic distribution was not analyzed.

EOS Terra Validation Program

NASA Technical Reports Server (NTRS)

Starr, David

2000-01-01

The EOS Terra mission will be launched in July 1999. This mission has great relevance to the atmospheric radiation community and global change issues. Terra instruments include Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Clouds and Earth's Radiant Energy System (CERES), Multi-Angle Imaging Spectroradiometer (MISR), Moderate Resolution Imaging Spectroradiometer (MODIS) and Measurements of Pollution in the Troposphere (MOPITT). In addition to the fundamental radiance data sets, numerous global science data products will be generated, including various Earth radiation budget, cloud and aerosol parameters, as well as land surface, terrestrial ecology, ocean color, and atmospheric chemistry parameters. Significant investments have been made in on-board calibration to ensure the quality of the radiance observations. A key component of the Terra mission is the validation of the science data products. This is essential for a mission focused on global change issues and the underlying processes. The Terra algorithms have been subject to extensive pre-launch testing with field data whenever possible. Intensive efforts will be made to validate the Terra data products after launch. These include validation of instrument calibration (vicarious calibration) experiments, instrument and cross-platform comparisons, routine collection of high quality correlative data from ground-based networks, such as AERONET, and intensive sites, such as the SGP ARM site, as well as a variety field experiments, cruises, etc. Airborne simulator instruments have been developed for the field experiment and underflight activities including the MODIS Airborne Simulator (MAS) AirMISR, MASTER (MODIS-ASTER), and MOPITT-A. All are integrated on the NASA ER-2 though low altitude platforms are more typically used for MASTER. MATR is an additional sensor used for MOPITT algorithm development and validation. The intensive validation activities planned for the first year of the Terra

SUV Tracks On Mars? The 'Devil' is in the Details

NASA Technical Reports Server (NTRS)

1998-01-01

Sport Utility Vehicles (SUVs) on Mars? Imagine the MOC imaging team's surprise on the morning of April 27, 1998, as the latest images came in from the 'Red Planet.'

A picture taken by the camera on Mars Global Surveyor just one day earlier showed several thin, dark lines that--at first glance--looked like pathways blazed by off-road sport utility vehicles. Who's been driving around on Mars?

The MOC image in question (#26403), seen here at full resolution of 13.8 meters (45 feet) per pixel, was obtained around 10:22 a.m. PDT on April 26, 1998, during Mars Global Surveyor's 264th orbit. North is approximately up, illumination is from the lower right. Located in eastern Arabia Terra near 16.5o N latitude, 311.4o W longitude, the image showed a number of natural features--small craters formed by meteor impact, several buttes and mesas left by erosion of the surrounding terrain, small dunes and drifts, and a mantle of dust that varies in thickness from place to place. But the new picture also showed two dark lines--each varying in width up to about 15 meters (49 feet)--that extended several kilometers/miles across the image.

Lines like these have been seen before on Mars. They are most likely the result of dust devils--columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes. Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars. They form when the ground heats up during the day, warming the air immediately above the surface. As pockets of warm air rise and interfere with one another, they create horizontal pressure variations that, combined with other meteorological winds, cause the upward moving air to spin (the direction of the spin is controlled by the same Coriolis forces that cause terrestrial hurricanes to spin in specific directions). As the spinning column of air moves across the surface, it occasionally encounters dust on the surface, which it can suck upward

The Terra Data Fusion Project: An Update

NASA Astrophysics Data System (ADS)

Di Girolamo, L.; Bansal, S.; Butler, M.; Fu, D.; Gao, Y.; Lee, H. J.; Liu, Y.; Lo, Y. L.; Raila, D.; Turner, K.; Towns, J.; Wang, S. W.; Yang, K.; Zhao, G.

2017-12-01

Terra is the flagship of NASA's Earth Observing System. Launched in 1999, Terra's five instruments continue to gather data that enable scientists to address fundamental Earth science questions. By design, the strength of the Terra mission has always been rooted in its five instruments and the ability to fuse the instrument data together for obtaining greater quality of information for Earth Science compared to individual instruments alone. As the data volume grows and the central Earth Science questions move towards problems requiring decadal-scale data records, the need for data fusion and the ability for scientists to perform large-scale analytics with long records have never been greater. The challenge is particularly acute for Terra, given its growing volume of data (> 1 petabyte), the storage of different instrument data at different archive centers, the different file formats and projection systems employed for different instrument data, and the inadequate cyberinfrastructure for scientists to access and process whole-mission fusion data (including Level 1 data). Sharing newly derived Terra products with the rest of the world also poses challenges. As such, the Terra Data Fusion Project aims to resolve two long-standing problems: 1) How do we efficiently generate and deliver Terra data fusion products? 2) How do we facilitate the use of Terra data fusion products by the community in generating new products and knowledge through national computing facilities, and disseminate these new products and knowledge through national data sharing services? Here, we will provide an update on significant progress made in addressing these problems by working with NASA and leveraging national facilities managed by the National Center for Supercomputing Applications (NCSA). The problems that we faced in deriving and delivering Terra L1B2 basic, reprojected and cloud-element fusion products, such as data transfer, data fusion, processing on different computer architectures

Peripheral Faulting of Eden Patera: Potential Evidence in Support of a New Volcanic Construct on Mars

NASA Astrophysics Data System (ADS)

Harlow, J.

2016-12-01

Arabia Terra's (AT) pock-marked topography in the expansive upland region of Mars Northern Hemisphere has been assumed to be the result of impact crater bombardment. However, examination of several craters by researchers revealed morphologies inconsistent with neighboring craters of similar size and age. These 'craters' share features with terrestrial super-eruption calderas, and are considered a new volcanic construct on Mars called `plains-style' caldera complexes. Eden Patera (EP), located on the northern boundary of AT is a reference type for these calderas. EP lacks well-preserved impact crater morphologies, including a decreasing depth to diameter ratio. Conversely, Eden shares geomorphological attributes with terrestrial caldera complexes such as Valles Caldera (New Mexico): arcuate caldera walls, concentric fracturing/faulting, flat-topped benches, irregular geometric circumferences, etc. This study focuses on peripheral fractures surrounding EP to provide further evidence of calderas within the AT region. Scaled balloon experiments mimicking terrestrial caldera analogs have showcased fracturing/faulting patterns and relationships of caldera systems. These experiments show: 1) radial fracturing (perpendicular to caldera rim) upon inflation, 2) concentric faulting (parallel to sub-parallel to caldera rim) during evacuation, and 3) intersecting radial and concentric peripheral faulting from resurgence. Utilizing Mars Reconnaissance Orbiter Context Camera (CTX) imagery, peripheral fracturing is analyzed using GIS to study variations in peripheral fracture geometries relative to the caldera rim. Visually, concentric fractures dominate within 20 km, radial fractures prevail between 20 and 50 km, followed by gradation into randomly oriented and highly angular intersections in the fretted terrain region. Rose diagrams of orientation relative to north expose uniformly oriented mean regional stresses, but do not illuminate localized caldera stresses. Further

To what extent can intracrater layered deposits that lack clear sedimentary textures be used to infer depositional environments?

NASA Astrophysics Data System (ADS)

Cadieux, Sarah B.; Kah, Linda C.

2015-03-01

Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata showing systematic alternation between slope- and cliff-forming units, suggesting either rhythmic deposition of distinct lithologies or similar lithologies that experienced differential cementation. On Earth, rhythmically deposited strata can be examined in terms of stratal packaging, wherein the interplay of tectonics, sediment deposition, and base level (i.e., the position above which sediment accumulation is expected to be temporary) result in changes in the amount of space available for sediment accumulation. These predictable patterns of sediment deposition can be used to infer changes in basin accommodation regardless of the mechanism of deposition (e.g. fluvial, lacustrine, or aeolian). Here, we analyze sedimentary deposits from three craters (Becquerel Crater, Danielson Crater, Crater A) in Arabia Terra. Each crater contains layered deposits that are clearly observed in orbital images. Although orbital images are insufficient to specifically determine the origin of sedimentary deposits, depositional couplets can be interpreted in terms of potential accommodation space available for deposition, and changes in the distribution of couplet thickness through stratigraphy can be interpreted in terms of changing base level and the production of new accommodation space. Differences in stratal packaging in these three craters suggest varying relationships between sedimentary influx, sedimentary base level, and concomitant changes in accommodation space. Previous groundwater upwelling models hypothesize that layered sedimentary deposits were deposited under warm climate conditions of early Mars. Here, we use observed stacking patterns to propose a model for deposition under cold climate conditions, wherein episodic melting of ground ice could raise local base level, stabilize sediment deposition, and result in differential cementation of accumulated strata. Such analysis demonstrates that

Recent ice ages on Mars.

PubMed

Head, James W; Mustard, John F; Kreslavsky, Mikhail A; Milliken, Ralph E; Marchant, David R

2003-12-18

A key pacemaker of ice ages on the Earth is climatic forcing due to variations in planetary orbital parameters. Recent Mars exploration has revealed dusty, water-ice-rich mantling deposits that are layered, metres thick and latitude dependent, occurring in both hemispheres from mid-latitudes to the poles. Here we show evidence that these deposits formed during a geologically recent ice age that occurred from about 2.1 to 0.4 Myr ago. The deposits were emplaced symmetrically down to latitudes of approximately 30 degrees--equivalent to Saudi Arabia and the southern United States on the Earth--in response to the changing stability of water ice and dust during variations in obliquity (the angle between Mars' pole of rotation and the ecliptic plane) reaching 30-35 degrees. Mars is at present in an 'interglacial' period, and the ice-rich deposits are undergoing reworking, degradation and retreat in response to the current instability of near-surface ice. Unlike the Earth, martian ice ages are characterized by warmer polar climates and enhanced equatorward transport of atmospheric water and dust to produce widespread smooth deposits down to mid-latitudes.

Recent ice ages on Mars

NASA Astrophysics Data System (ADS)

Head, James W.; Mustard, John F.; Kreslavsky, Mikhail A.; Milliken, Ralph E.; Marchant, David R.

2003-12-01

A key pacemaker of ice ages on the Earth is climatic forcing due to variations in planetary orbital parameters. Recent Mars exploration has revealed dusty, water-ice-rich mantling deposits that are layered, metres thick and latitude dependent, occurring in both hemispheres from mid-latitudes to the poles. Here we show evidence that these deposits formed during a geologically recent ice age that occurred from about 2.1 to 0.4 Myr ago. The deposits were emplaced symmetrically down to latitudes of ~30°-equivalent to Saudi Arabia and the southern United States on the Earth-in response to the changing stability of water ice and dust during variations in obliquity (the angle between Mars' pole of rotation and the ecliptic plane) reaching 30-35°. Mars is at present in an `interglacial' period, and the ice-rich deposits are undergoing reworking, degradation and retreat in response to the current instability of near-surface ice. Unlike the Earth, martian ice ages are characterized by warmer polar climates and enhanced equatorward transport of atmospheric water and dust to produce widespread smooth deposits down to mid-latitudes.

TerraSAR-X mission

NASA Astrophysics Data System (ADS)

Werninghaus, Rolf

2004-01-01

The TerraSAR-X is a German national SAR- satellite system for scientific and commercial applications. It is the continuation of the scientifically and technologically successful radar missions X-SAR (1994) and SRTM (2000) and will bring the national technology developments DESA and TOPAS into operational use. The space segment of TerraSAR-X is an advanced high-resolution X-Band radar satellite. The system design is based on a sound market analysis performed by Infoterra. The TerraSAR-X features an advanced high-resolution X-Band Synthetic Aperture Radar based on the active phased array technology which allows the operation in Spotlight-, Stripmap- and ScanSAR Mode with various polarizations. It combines the ability to acquire high resolution images for detailed analysis as well as wide swath images for overview applications. In addition, experimental modes like the Dual Receive Antenna Mode allow for full-polarimetric imaging as well as along track interferometry, i.e. moving target identification. The Ground Segment is optimized for flexible response to (scientific and commercial) User requests and fast image product turn-around times. The TerraSAR-X mission will serve two main goals. The first goal is to provide the strongly supportive scientific community with multi-mode X-Band SAR data. The broad spectrum of scientific application areas include Hydrology, Geology, Climatology, Oceanography, Environmental Monitoring and Disaster Monitoring as well as Cartography (DEM Generation) and Interferometry. The second goal is the establishment of a commercial EO-market in Europe which is driven by Infoterra. The commercial goal is the development of a sustainable EO-business so that the e.g. follow-on systems can be completely financed by industry from the profit. Due to its commercial potential, the TerraSAR-X project will be implemented based on a public-private partnership with the Astrium GmbH. This paper will describe first the mission objectives as well as the

Laboratory investigation of TerraZyme as a soil stabilizer

NASA Astrophysics Data System (ADS)

Yusoff, Siti Aimi Nadia Mohd; Azmi, Mastura; Ramli, Harris; Bakar, Ismail; Wijeyesekera, D. C.; Zainorabidin, Adnan

2017-10-01

In this study, a laboratory investigation was conducted to examine the performance of TerraZyme on different soil types. Laterite and kaolin were treated with 2% and 5% TerraZyme to determine changes in the soils' geotechnical properties. The obtained results were analysed and investigated in terms of compaction, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR). The changes in geotechnical properties of the stabilised and unstabilised soils were monitored after curing periods of 0, 7, 15, 21 and 30 days. Changes in compaction properties, UCS and CBR were observed. It was found that laterite with 5% TerraZyme gave a higher maximum dry density (MDD) and decreased the optimum moisture content (OMC). For kaolin, a different TerraZyme percentage did not show any effect on both MDD and OMC. For strength properties, it was found that 2% TerraZyme showed the greatest change in UCS over a 30-day curing period. The CBR value of stabilised kaolin with 2% TerraZyme gave a higher CBR value than the kaolin treated with 5% TerraZyme. It was also found that laterite treated with TerraZyme gave a higher CBR value. Lastly, it can be concluded that TerraZyme is not suitable for stabilising kaolin; TerraZyme requires a cohesive soil to achieve a better performance.

Variable TERRA abundance and stability in cervical cancer cells.

PubMed

Oh, Bong-Kyeong; Keo, Ponnarath; Bae, Jaeman; Ko, Jung Hwa; Choi, Joong Sub

2017-06-01

Telomeres are transcribed into long non-coding RNA, referred to as telomeric repeat-containing RNA (TERRA), which plays important roles in maintaining telomere integrity and heterochromatin formation. TERRA has been well characterized in HeLa cells, a type of cervical cancer cell. However, TERRA abundance and stability have not been examined in other cervical cancer cells, at least to the best of our knowledge. Thus, in this study, we measured TERRA levels and stability, as well as telomere length in 6 cervical cancer cell lines, HeLa, SiHa, CaSki, HeLa S3, C-33A and SNU-17. We also examined the association between the TERRA level and its stability and telomere length. We found that the TERRA level was several fold greater in the SiHa, CaSki, HeLa S3, C-33A and SNU-17 cells, than in the HeLa cells. An RNA stability assay of actinomycin D-treated cells revealed that TERRA had a short half-life of ~4 h in HeLa cells, which was consistent with previous studies, but was more stable with a longer half-life (>8 h) in the other 5 cell lines. Telomere length varied from 4 to 9 kb in the cells and did not correlate significantly with the TERRA level. On the whole, our data indicate that TERRA abundance and stability vary between different types of cervical cancer cells. TERRA degrades rapidly in HeLa cells, but is maintained stably in other cervical cancer cells that accumulate higher levels of TERRA. TERRA abundance is associated with the stability of RNA in cervical cancer cells, but is unlikely associated with telomere length.

Lunar and Planetary Science XXXV: Mars Volcanology and Tectonics

NASA Technical Reports Server (NTRS)

2004-01-01

Reports from the session, "Mars Volcanology and Tectonics" include:Martian Shield Volcanoes; Estimating the Rheology of Basaltic Lava Flows; A Model for Variable Levee Formation Rates in an Active Lava Flow; Deflections in Lava Flow Directions Relative to Topography in the Tharsis Region: Indicators of Post-Flow Tectonic Motion; Fractal Variation with Changing Line Length: A Potential Problem for Planetary Lava Flow Identification; Burfellshraun:A Terrestrial Analogue to Recent Volcanism on Mars; Lava Domes of the Arcadia Region of Mars; Comparison of Plains Volcanism in the Tempe Terra Region of Mars to the Eastern Snake River Plains, Idaho with Implications for Geochemical Constraints; Vent Geology of Low-Shield Volcanoes from the Central Snake River Plain, Idaho: Lessons for Mars and the Moon; Field and Geochemical Study of Table Legs Butte and Quaking Aspen Butte, Eastern Snake River Plain, Idaho: An Analog to the Morphology of Small Shield Volcanoes on Mars; Variability in Morphology and Thermophysical Properties of Pitted Cones in Acidalia Planitia and Cydonia Mensae; A Volcano Composed of Light-colored Layered Deposits on the Floor of Valles Marineris; Analysis of Alba Patera Flows: A Comparison of Similarities and Differences Geomorphologic Studies of a Very Long Lava Flow in Tharsis, Mars; Radar Backscatter Characteristics of Basaltic Flow Fields: Results for Mauna Ulu, Kilauea Volcano, Hawaii;and Preliminary Lava Tube-fed Flow Abundance Mapping on Olympus Mons.

Barchan Dunes

NASA Technical Reports Server (NTRS)

2004-01-01

28 April 2004 One of the simplest forms a sand dune can take is the barchan. The term, apparently, comes from the Arabic word for crescent-shaped dunes. They form in areas with a single dominant wind direction that are also not overly-abundant in sand. The barchan dunes shown here were imaged in March 2004 by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) as it passed over a crater in western Arabia Terra near 21.1oN, 17.6oW. The horns and steep slope on each dune, known as the slip face, point toward the south, indicating prevailing winds from the north (top). The picture covers an area about 3 km (1.9 mi) across and is illuminated by sunlight from the lower left.

Martian plate tectonics

NASA Astrophysics Data System (ADS)

Sleep, N. H.

1994-03-01

The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses

Terra - the Earth Observing System flagship observatory

NASA Astrophysics Data System (ADS)

Thome, K. J.

2013-12-01

The Terra platform enters its teenage years with an array of accomplishments but also with the potential to do much more. Efforts continue to extend the Terra data record to build upon its array of accomplishments and make its data more valuable by creating a record length that allows examination of inter annual variability, observe trends on the decadal scale, and gather statistics relevant to the define climate metrics. Continued data from Terra's complementary instruments will play a key role in creating the data record needed for scientists to develop an understanding of our climate system. Terra's suite of instruments: ASTER (contributed by the Japanese Ministry of Economy and Trade and Industry with a JPL-led US Science Team), CERES (NASA LaRC - PI), MISR (JPL - PI), MODIS (NASA GSFC), and MOPITT (sponsored by Canadian Space Agency with NCAR-led Science Team) are providing an unprecedented 81 core data products. The annual demand for Terra data remains with >120 million files distributed in 2011 and >157 million in 2012. More than 1,100 peer-reviewed publications appeared in 2012 using Terra data bringing the lifetime total >7,600. Citation numbers of 21,000 for 2012 and over 100,000 for the mission's lifetime. The broad range of products enable the community to provide answers to the overarching question, 'How is the Earth changing and what are the consequences for life on Earth?' Terra continues to provide data that: (1) Extend the baseline of morning-orbit collections; (2) Enable comparison of measurements acquired from past high-impact events; (3) Add value to recently-launched and soon-to-be launched missions, and upcoming field programs. Terra data continue to support monitoring and relief efforts for natural and man-made disasters that involve U.S. interests. Terra also contributes to Applications Focus Areas supporting the U.S. National Objectives for agriculture, air quality, climate, disaster management, ecological forecasting, public health, water

Sulfates on Mars: Indicators of Aqueous Processes

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Lane, Melissa D.; Dyar, M. Darby; Brown, Adrian J.

2006-01-01

Recent analyses by MER instruments at Meridiani Planum and Gusev crater and the OMEGA instrument on Mars Express have provided detailed information about the presence of sulfates on Mars [1,2,3]. We are evaluating these recent data in an integrated multi-disciplinary study of visible-near-infrared, mid-IR and Mossbauer spectra of several sulfate minerals and sulfate-rich analog sites. Our analyses suggest that hydrated iron sulfates may account for features observed in Mossbauer and mid-IR spectra of Martian soils [4]. The sulfate minerals kieserite, gypsum and other hydrated sulfates have been identified in OMEGA spectra in the layered terrains in Valles Marineris and Terra Meridiani [2]. These recent discoveries emphasize the importance of studying sulfate minerals as tracers of aqueous processes. The sulfate-rich rock outcrops observed in Meridiani Planum may have formed in an acidic environment similar to acid rock drainage environments on Earth [5]. Because microorganisms typically are involved in the oxidation of sulfides to sulfates in terrestrial sites, sulfate-rich rock outcrops on Mars may be a good location to search for evidence of past life on that planet. Whether or not life evolved on Mars, following the trail of sulfate minerals will lead to a better understanding of aqueous processes and chemical weathering.

Regional-scale stratigraphy of surface units in Tyrrhena and Iapygia Terrae, Mars: insights into highland crustal evolution and alteration history

USGS Publications Warehouse

Rogers, A. Deanne; Fergason, Robin L.

2011-01-01

The compositional, thermophysical and geologic characteristics of surface units in Iapygia and Tyrrhena Terra (60°E-100°E, 0°-30°S) provide new insights into the compositional stratigraphy of the region. Intercrater plains are dominated by two surface units. The older unit (unit 1) is deficient in olivine and more degraded and likely consists of a mixture of impact, volcanic and sedimentary materials. The younger unit (unit 2) is enriched in olivine, exhibits a resistant morphology and higher thermal inertia, and likely represents volcanic infilling of plains. Units 1 and 2 bear a strong resemblance to those previously mapped in Mare Serpentis, a section of highlands crust located northwest of Hellas Basin. Thus, the two major intercrater plains units are even more widespread than previously thought and therefore likely constitute important components of Mars' highland stratigraphy. Many craters in the region contain high thermal inertia deposits (unit 3) that are compositionally identical to unit 2. These may have formed via volcanic infilling or may represent sedimentary materials that have been eroded from crater walls and lithified. Less common units include olivine and/or pyroxene-rich massifs and crater central peaks. These are primarily found within Hellas Basin rim units and may represent mantle materials brought toward the surface during the Hellas impact. Putative chloride deposits are primarily associated with olivine-deficient surfaces (unit 1) that may be heavily degraded occurrences of unit 2. The observations raise a variety of questions related to Martian crustal evolution and alteration that may have more widespread implications outside the study region.

Saudi Arabia Country Analysis Brief

EIA Publications

2014-01-01

Saudi Arabia is the world's largest holder of crude oil proved reserves and was the largest exporter of total petroleum liquids in 2013. In 2013, Saudi Arabia was the world's second-largest petroleum liquids producer behind the United States and was the world's second-largest crude oil producer behind Russia. Saudi Arabia's economy remains heavily dependent on petroleum. Petroleum exports accounted for 85% of total Saudi export revenues in 2013, according to the Organization of the Petroleum Exporting Countries (OPEC)'s Annual Statistical Bulletin 2014. With the largest oil projects nearing completion, Saudi Arabia is expanding its natural gas, refining, petrochemicals, and electric power industries. Saudi Arabia's oil and natural gas operations are dominated by Saudi Aramco, the national oil and gas company and the world's largest oil company in terms of production. Saudi Arabia's Ministry of Petroleum and Mineral Resources and the Supreme Council for Petroleum and Minerals have oversight of the oil and natural gas sector and Saudi Aramco.

Terra Mission Operations: Launch to the Present (and Beyond)

NASA Technical Reports Server (NTRS)

Thome, Kurt; Kelly, Angelita; Moyer, Eric; Mantziaras, Dimitrios; Case, Warren

2014-01-01

The Terra satellite, flagship of NASAs long-term Earth Observing System (EOS) Program, continues to provide useful earth science observations well past its 5-year design lifetime. This paper describes the evolution of Terra operations, including challenges and successes and the steps taken to preserve science requirements and prolong spacecraft life. Working cooperatively with the Terra science and instrument teams, including NASAs international partners, the mission operations team has successfully kept the Terra operating continuously, resolving challenges and adjusting operations as needed. Terra retains all of its observing capabilities (except Short Wave Infrared) despite its age. The paper also describes concepts for future operations.

The Earth Observing System Terra Mission

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.

2000-01-01

Langley's remarkable solar and lunar spectra collected from Mt. Whitney inspired Arrhenius to develop the first quantitative climate model in 1896. After the launch in Dec. 16 1999, NASA's Earth Observing AM Satellite (EOS-Terra) will repeat Langley's experiment, but for the entire planet, thus pioneering a wide array of calibrated spectral observations from space of the Earth System. Conceived in response to real environmental problems, EOS-Terra, in conjunction with other international satellite efforts, will fill a major gap in current efforts by providing quantitative global data sets with a resolution smaller than 1 km on the physical, chemical and biological elements of the earth system. Thus, like Langley's data, EOS-Terra can revolutionize climate research by inspiring a new generation of climate system models and enable us to assess the human impact on the environment. In the talk I shall review the historical perspective of the Terra mission and the key new elements of the mission. We expect to have some first images that demonstrate the most innovative capability from EOS Terra: MODIS - 1.37 microns cirrus channel; 250 m daily cover for clouds and vegetation change; 7 solar channels for land and aerosol; new fire channels; Chlorophyll fluorescence; MISR - 9 multi angle views of clouds and vegetation; MOPITT - Global CO maps and CH4 maps; ASTER - Thermal channels for geological studies with 15-90 m resolution.

Lunar and Planetary Science XXXV: Mars: Hydrology, Drainage, and Valley Systems

NASA Technical Reports Server (NTRS)

2004-01-01

The titles in this section include: 1) Analysis of Orientation Dependence of Martian Gullies; 2) A Preliminary Relationship between the Depth of Martian Gullies and the Abundance of Hydrogen on Near-Surface Mars; 3) Water Indicators in Sirenum Terra and around the Argyre Impact Basin, Mars; 4) The Distribution of Gullies and Tounge-shaped Ridges and Their Role in the Degradation of Martian Craters; 5) A Critical Evaluation of Crater Lake Systems in Memnonia Quadrangle, Mars; 6) Impact-generated Hydrothermal Activity at Gusev Crater: Implications for the Spirit Mission; 7) Characterization of the Distributary Fan in Holden NE Crater using Stereo Analysis; 8) Computational Analysis of Drainage Basins on Mars: Appraising the Drainage Density; 9) Hypsometric Analyses of Martian Basins: A Comparison to Terrestrial, Lunar, and Venusian Hypsometry; 10) Morphologic Development of Harmakhis Vallis, Mars; 11) Mangala Valles, Mars: Investigations of the source of Flood Water and Early Stages of Flooding; 12) The Formation of Aromatum Chaos and the Water Discharge Rate at Ravi Vallis; 13) Inferring Hydraulics from Geomorphology for Athabasca Valles, Mars; 14) The Origin and Evolution of Dao Vallis: Formation and Modification of Martian Channels by Structural Collapse and Glaciation; 15) Snowmelt and the Formation of Valley Networks on Martian Volcanoes; 16) Extent of Floating Ice in an Ancient Echus Chasma/Kasei Valley System, Mars.

Science Writers' Guide to TERRA

NASA Technical Reports Server (NTRS)

2000-01-01

The launch of NASA's Terra spacecraft marks a new era of comprehensive monitoring of the Earth's atmosphere, oceans, and continents from a single space-based platform. Data from the five Terra instruments will create continuous, long-term records of the state of the land, oceans, and atmosphere. Together with data from other satellite systems launched by NASA and other countries, Terra will inaugurate a new self-consistent data record that will be gathered over the next 15 years. The science objectives of NASAs Earth Observing System (EOS) program are to provide global observations and scientific understanding of land cover change and global productivity, climate variability and change, natural hazards, and atmospheric ozone. Observations by the Terra instruments will: provide the first global and seasonal measurements of the Earth system, including such critical functions as biological productivity of the land and oceans, snow and ice, surface temperature, clouds, water vapor, and land cover; improve our ability to detect human impacts on the Earth system and climate, identify the "fingerprint" of human activity on climate, and predict climate change by using the new global observations in climate models; help develop technologies for disaster prediction, characterization, and risk reduction from wildfires, volcanoes, floods, and droughts, and start long-term monitoring of global climate change and environmental change.

Effect of MODIS Terra Radiometric Calibration Improvements on Collection 6 Deep Blue Aerosol Products: Validation and Terra/Aqua Consistency

NASA Technical Reports Server (NTRS)

Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.; Jeong, M.-J.; Meister, G.

2015-01-01

The Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by approximately 0.04 over bright (e.g., desert) and approximately 0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by approximately 10% and approximately 5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.

Terra Mission Operations: Launch to the Present (and Beyond)

NASA Technical Reports Server (NTRS)

Kelly, Angelita; Moyer, Eric; Mantziaras, Dimitrios; Case, Warren

2014-01-01

The Terra satellite, flagship of NASA's long-term Earth Observing System (EOS) Program, continues to provide useful earth science observations well past its 5-year design lifetime. This paper describes the evolution of Terra operations, including challenges and successes and the steps taken to preserve science requirements and prolong spacecraft life. Working cooperatively with the Terra science and instrument teams, including NASA's international partners, the mission operations team has successfully kept the Terra operating continuously, resolving challenges and adjusting operations as needed. Terra retains all of its observing capabilities (except Short Wave Infrared) despite its age. The paper also describes concepts for future operations. This paper will review the Terra spacecraft mission successes and unique spacecraft component designs that provided significant benefits extending mission life and science. In addition, it discusses special activities as well as anomalies and corresponding recovery efforts. Lastly, it discusses future plans for continued operations.

Arabia and Memnonia Equatorial Regions with High Content of Water: Data from HEND/Odyssey

NASA Technical Reports Server (NTRS)

Mitrofaov, I. G.; Litvak, M. L.; Kozyrev, A. S.; Sanin, A. B.; Tretyakov, V. I.; Boynton, W. V.; Hamara, D. K.; Shinohara, C.; Saunders, R. S.

2004-01-01

After one martian year of neutron mapping measurements by the High Energy Neutron Detector (HEND) onboard the Mars Odyssey spacecraft, a map of the planet was produced showing the summer season in each hemisphere when winter deposition of CO2 on the surface is absent. The data for northern and southern poleward water-rich regions are presented. Here we discuss the HEND results for two equatorial regions, Arabia and Memnonia, which were found to be associated with a rather strong depression of epithermal and high energy neutrons.

The Earth Observing System Terra Mission

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.; Einaudi, Franco (Technical Monitor)

2000-01-01

Langley's remarkable solar and lunar spectra collected from Mt. Whitney inspired Arrhenius to develop the first quantitative climate model in 1896. After the launch in Dec. 16 1999, NASA's Earth Observing AM Satellite (EOS-Terra) will repeat Langley's experiment, but for the entire planet, thus pioneering a wide array of calibrated spectral observations from space of the Earth System. Conceived in response to real environmental problems, EOS-Terra, in conjunction with other international satellite efforts, will fill a major gap in current efforts by providing quantitative global data sets with a resolution better than 1 km on the physical, chemical and biological elements of the earth system. Thus, like Langley's data, EOS-Terra can revolutionize climate research by inspiring a new generation of climate system models and enable us to assess the human impact on the environment. In the talk I shall review the historical perspective of the Terra mission and the key new elements of the mission. We expect to have first images that demonstrate the most innovative capability from EOS Terra 5 instruments: MODIS - 1.37 micron cirrus cloud channel; 250m daily coverage for clouds and vegetation change; 7 solar channels for land and aerosol studies; new fire channels; Chlorophyll fluorescence; MISR - first 9 multi angle views of clouds and vegetation; MOPITT - first global CO maps and C114 maps; ASTER - Thermal channels for geological studies with 15-90 m resolution.

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-01

This image shows individual dunes on the floor of Russell Crater. These dunes are in the southern part of the dune field. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! https://photojournal.jpl.nasa.gov/catalog/PIA21799

[Lung infection by Mycobacterium terrae].

PubMed

Díaz Ricomá, N; González Vargas, F; Casado Moreno, I; Galán Antoñanza, L; Rojas Sierra, M; Alado Arboleda, J C

2001-02-01

Mycobacterium terrae complex encompasses three species of microbacteria that are usually saprophytic and that may occasionally cause disease in humans, particularly in joints and synovial fluid. The literature includes slightly over a dozen cases of pulmonary infection, although none has been described in Spain. We report a case of infection by M. terrae in an immunodepressed patient with no other risk factor. Microbial identification by culture was unexpected and clinical management was difficult due to the absence of an established treatment protocol.

Quantitative interaction screen of telomeric repeat-containing RNA reveals novel TERRA regulators

PubMed Central

Scheibe, Marion; Arnoult, Nausica; Kappei, Dennis; Buchholz, Frank; Decottignies, Anabelle; Butter, Falk; Mann, Matthias

2013-01-01

Telomeres are actively transcribed into telomeric repeat-containing RNA (TERRA), which has been implicated in the regulation of telomere length and heterochromatin formation. Here, we applied quantitative mass spectrometry (MS)–based proteomics to obtain a high-confidence interactome of TERRA. Using SILAC-labeled nuclear cell lysates in an RNA pull-down experiment and two different salt conditions, we distinguished 115 proteins binding specifically to TERRA out of a large set of background binders. While TERRA binders identified in two previous studies showed little overlap, using quantitative mass spectrometry we obtained many candidates reported in these two studies. To test whether novel candidates found here are involved in TERRA regulation, we performed an esiRNA-based interference analysis for 15 of them. Knockdown of 10 genes encoding candidate proteins significantly affected total cellular levels of TERRA, and RNAi of five candidates perturbed TERRA recruitment to telomeres. Notably, depletion of SRRT/ARS2, involved in miRNA processing, up-regulated both total and telomere-bound TERRA. Conversely, knockdown of MORF4L2, a component of the NuA4 histone acetyltransferase complex, reduced TERRA levels both globally and for telomere-bound TERRA. We thus identified new proteins involved in the homeostasis and telomeric abundance of TERRA, extending our knowledge of TERRA regulation. PMID:23921659

Regional-scale stratigraphy of surface units in Tyrrhena and Iapygia Terrae, Mars: Insights into highland crustal evolution and alteration history

USGS Publications Warehouse

Rogers, A.D.; Fergason, R.L.

2011-01-01

The compositional, thermophysical and geologic characteristics of surface units in Iapygia and Tyrrhena Terra (60??E-100??E, 0??-30??S) provide new insights into the compositional stratigraphy of the region. Intercrater plains are dominated by two surface units. The older unit (unit 1) is deficient in olivine and more degraded and likely consists of a mixture of impact, volcanic and sedimentary materials. The younger unit (unit 2) is enriched in olivine, exhibits a resistant morphology and higher thermal inertia, and likely represents volcanic infilling of plains. Units 1 and 2 bear a strong resemblance to those previously mapped in Mare Serpentis, a section of highlands crust located northwest of Hellas Basin. Thus, the two major intercrater plains units are even more widespread than previously thought and therefore likely constitute important components of Mars' highland stratigraphy. Many craters in the region contain high thermal inertia deposits (unit 3) that are compositionally identical to unit 2. These may have formed via volcanic infilling or may represent sedimentary materials that have been eroded from crater walls and lithified. Less common units include olivine and/or pyroxene-rich massifs and crater central peaks. These are primarily found within Hellas Basin rim units and may represent mantle materials brought toward the surface during the Hellas impact. Putative chloride deposits are primarily associated with olivine-deficient surfaces (unit 1) that may be heavily degraded occurrences of unit 2. The observations raise a variety of questions related to Martian crustal evolution and alteration that may have more widespread implications outside the study region. Copyright ?? 2011 by the American Geophysical Union.

Preservation of Late Amazonian Mars ice and water-related deposits in a unique crater environment in Noachis Terra: Age relationships between lobate debris tongues and gullies

NASA Astrophysics Data System (ADS)

Morgan, Gareth A.; Head, James W.; Marchant, David R.

2011-01-01

The Amazonian period of Mars has been described as static, cold, and dry. Recent analysis of high-resolution imagery of equatorial and mid-latitude regions has revealed an array of young landforms produced in association with ice and liquid water; because near-surface ice in these regions is currently unstable, these ice-and-water-related landforms suggest one or more episodes of martian climate change during the Amazonian. Here we report on the origin and evolution of valley systems within a degraded crater in Noachis Terra, Asimov Crater. The valleys have produced a unique environment in which to study the geomorphic signals of Amazonian climate change. New high-resolution images reveal Hesperian-aged layered basalt with distinctive columnar jointing capping interior crater fill and providing debris, via mass wasting, for the surrounding annular valleys. The occurrence of steep slopes (>20°), relatively narrow (sheltered) valleys, and a source of debris have provided favorable conditions for the preservation of shallow-ice deposits. Detailed mapping reveals morphological evidence for viscous ice flow, in the form of several lobate debris tongues (LDT). Superimposed on LDT are a series of fresh-appearing gullies, with typical alcove, channel, and fan morphologies. The shift from ice-rich viscous-flow formation to gully erosion is best explained as a shift in martian climate, from one compatible with excess snowfall and flow of ice-rich deposits, to one consistent with minor snow and gully formation. Available dating suggests that the climate transition occurred >8 Ma, prior to the formation of other small-scale ice-rich flow features identified elsewhere on Mars that have been interpreted to have formed during the most recent phases of high obliquity. Taken together, these older deposits suggest that multiple climatic shifts have occurred over the last tens of millions of years of martian history.

TERRA: Building New Communities for Advanced Biofuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cornelius, Joe; Mockler, Todd; Tuinstra, Mitch

ARPA-E’s Transportation Energy Resources from Renewable Agriculture (TERRA) program is bringing together top experts from different disciplines – agriculture, robotics and data analytics – to rethink the production of advanced biofuel crops. ARPA-E Program Director Dr. Joe Cornelius discusses the TERRA program and explains how ARPA-E’s model enables multidisciplinary collaboration among diverse communities. The video focuses on two TERRA projects—Donald Danforth Center and Purdue University—that are developing and integrating cutting-edge remote sensing platforms, complex data analytics tools and plant breeding technologies to tackle the challenge of sustainably increasing biofuel stocks.

Seasonal Frost in Terra Sirenum

NASA Technical Reports Server (NTRS)

2006-01-01

This image of the Terra Sirenum region of Mars was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 0918 UTC (4:18 a.m. EST) on Nov. 25, 2006, near 38.9 degrees south latitude, 195.9 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 18 meters (60 feet) across.

At this time, Mars' southern hemisphere was experiencing mid-winter. During Martian southern winter, the southern polar cap is covered and surrounded by carbon dioxide frost and water frost. This is unlike Earth, whose frozen winter precipitation is made up of only one volatile -- water. The carbon dioxide frost evaporates, or sublimates, at a lower temperature than water frost. So, during spring, the carbon dioxide ice evaporates first and leaves a residue of water frost, which later sublimates as well.

The image shown here covers part of a crater rim, which is illuminated from the upper left. North is at the top. The topography creates a cold microenvironment on the south side of the rim that is partially protected from solar illumination. That cold surface contains an outlier of the southern seasonal frost about 15 degrees of latitude closer to the equator than the average edge of the frost at this season.

The top image was constructed from three infrared wavelengths that highlight the bluer color of frost than the background rock and soil. Note that the frost occurs both on sunlit and shaded surfaces on the south side of the rim. The shaded areas are still visible because they are illuminated indirectly by the Martian sky.

The bottom image was constructed by measuring the depths of spectral absorption bands due to water frost and carbon dioxide frost, and displaying the results in image form. Blue shows strength of an absorption due to water frost near 1.50 micrometers, and green shows strength of an absorption due to carbon dioxide frost near 1.45 micrometers. Red shows

Mission Applications of a HIAD for the Mars Southern Highlands

NASA Technical Reports Server (NTRS)

Winski, Richard; Bose, Dave; Komar, David R.; Samareh, Jamshid

2013-01-01

Recent discoveries of evidence of a flowing liquid in craters throughout the Mars Southern Highlands, like Terra Sirenum, have spurred interest in sending science missions to those locations; however, these locations are at elevations that are much higher (0 to +4 km MOLA) than any previous landing site (-1 to -4 km MOLA). New technologies may be needed to achieve a landing at these sites with significant payload mass to the surface. A promising technology is the hypersonic inflatable aerodynamic decelerator (HIAD); a number of designs have been advanced but the stacked torus has been recently successfully flight tested in the IRVE-2 and IRVE-3 projects through the NASA Langley Research Center. This paper will focus on a variety of mission applications of the stacked torus type attached HIAD to the Mars southern highlands.

Xanthe Terra Landslide in IR

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

This is a daytime IR image of a chaos region within Xanthe Terra. As with earlier images, the landslide in this image is caused by the failure of steep slopes releasing material to form the landslide deposit.

Image information: IR instrument. Latitude 3.1, Longitude 309.7 East (50.3 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Tabanidae (Diptera) of Saudi Arabia

PubMed Central

Al Dhafer, H.M.; Dawah, H.A.; Abdullah, M.A.

2009-01-01

Samples were collected from southern, central and eastern regions of Saudi Arabia using Malaise traps and sweep nets. Nine species of Tabanidae were identified, two for the first time from Saudi Arabia, Hybomitra peculiaris (Szilády) and Atylotus pulchellus (Loew). Therefore, the total number of Tabanidae in Saudi Arabia is 31 species. Remarks of the species recorded in this study were given. A key to the genera of Tabanidae occurring in the Arabian Peninsula is also provided. Available literature for Saudi Arabian Tabanidae is summarized and provided. It is concluded that the tabanid fauna of Saudi Arabia is more similar to that of the Palaearctic region than to the Afrotropical region. PMID:23961046

Blueberries on Earth and Mars: Some Correlations Between Andean Paleosols, Geothermal Pipes in Navajo Sandstone and Terra Meridiani on Mars

NASA Astrophysics Data System (ADS)

Mahaney, W. C.; Milner, M. W.; Netoff, D. I.; Dohm, J. M.; Sodhi, R. N. S.; Aufreiter, S.; Hancock, R. G. V.; Bezada, M.; Kalm, V.; Malloch, D.

2006-03-01

The origin of "blueberries" on Mars and their relationship to similar concretionary forms on Earth invokes a process of variable redox conditions in underground fluids. The possible role of microorganisms in the origin of bluberries opens an avenue for biological investigations.

Which processes form the volcanic sands on Mars?

NASA Astrophysics Data System (ADS)

Grégoire, M.; Baratoux, D.; Mangold, N.; Arnalds, O.; Platvoet, B.; Bardinzeff, J.; Pinet, P.

2007-12-01

Volcanic sands are common at the surface of Mars. They are usually of basaltic composition. Occurrence of sands, mostly recognized as dark dune fields include numerous impact craters in the southern hemisphere [1], several volcanic provinces such as Cerberus and Syrtis Major[2], several impact craters in the northern hemisphere, the large basins (Hellas and Argyre), Valles Marineris, and the poles [3]. In most cases, the sands are of basaltic composition [2,4], at the exception of the polar dunes which are made of sulfates [3]. It is interesting to note that dunes have been found on the Hesperian volcanic plateau of Systis Major, while they are not reported on Tyrrhena Terra, a volcanic province similar in age and morphology to Syrtis. It seems thus that the formation of sand from volcanic material is not systematic and thus requires particular conditions. These different situations which will be presented raise the following questions. When did these volcanic sands form in the Martian history? Did they result from a long-standing and slow process operating in the present cold conditions or did they result from several episodes associated for instant to climate changes? We review several mechanisms which could account for the formation of volcanic sand on Mars from the volcanic material. In particular, we focus on the role of cold-climate processes from an analysis of terrestrial analogs in Iceland. In this case, the advance and retreat of glaciers over a recent erupted shield volcano associated with the strong catabatic winds have resulted in the rapid formation (less than few thousands years) of large volumes of sands. [1] Fenton, L. K. (2005), Potential sand sources for the dune fields in Noachis Terra, Mars, J. Geophys. Res. 110, E11004, doi :10.1029/2005JE002436. [2] Vaucher et. al, in revision for Icarus [3] Langevin et. al, (2005), Science, 307, 1584-1586 [4] Poulet F., Mangold N. and Erard S. (2003), Astron. & Astrophys. 412, L19-L23.

Telomeric repeat-containing RNA (TERRA) related to polycystic ovary syndrome (PCOS).

PubMed

Wang, Caiqin; Shen, Fengxian; Zhu, Yuning; Fang, Yuying; Lu, Shiming

2017-04-01

Telomeric repeat-containing RNA (TERRA) participates in the regulation of telomere length, and leucocyte telomere length (LTL) plays an important role in the pathophysiology of polycystic ovary syndrome (PCOS), but little is known about the role of TERRA in PCOS. To evaluate the role of TERRA and peripheral blood LTL in PCOS. Forty women with PCOS and 35 healthy women without PCOS were recruited. A prospective case-control study was performed. RNA fluorescence in situ hybridization (FISH) was used to detect TERRA expression in peripheral blood leucocyte. Quantitative PCR was used to measure TERRA expression and the mean LTL in the PCOS and control groups. We analysed the association between related clinical parameters and the age-adjusted ratio of the telomere repeat length (T/S ratio) or TERRA. Telomeric repeat-containing RNA was expressed in human peripheral blood leucocytes, and the signal was abolished after culture with RNase A. The age-adjusted LTLs were significantly longer in the PCOS group than in the control group (P < 0·01). The age-adjusted TERRA level was significantly lower in the PCOS group than in the control group (P < 0·01). Testosterone (TTE) was related positively to LTL and negatively to TERRA in the PCOS group (r = 0·532, P = 0·002; r = -0·477, P = 0·017). We found TERRA expression in human peripheral blood leucocytes, and LTLs were positively associated with PCOS. TERRA and testosterone play an important role in the LTL regulation in PCOS. © 2016 John Wiley & Sons Ltd.

TERRA: Building New Communities for Advanced Biofuels

ScienceCinema

Cornelius, Joe; Mockler, Todd; Tuinstra, Mitch

2018-01-16

ARPA-E’s Transportation Energy Resources from Renewable Agriculture (TERRA) program is bringing together top experts from different disciplines – agriculture, robotics and data analytics – to rethink the production of advanced biofuel crops. ARPA-E Program Director Dr. Joe Cornelius discusses the TERRA program and explains how ARPA-E’s model enables multidisciplinary collaboration among diverse communities. The video focuses on two TERRA projects—Donald Danforth Center and Purdue University—that are developing and integrating cutting-edge remote sensing platforms, complex data analytics tools and plant breeding technologies to tackle the challenge of sustainably increasing biofuel stocks.

Terra firma-forme dermatosis: a retrospective review of 31 patients.

PubMed

Berk, David R

2012-01-01

Terra firma-forme dermatosis is an idiopathic condition characterized by acquired, dirtlike plaques despite normal hygiene. A diagnosis can be reached by removing lesions with gentle alcohol swabbing. Although Terra firma-forme dermatosis was first described more than 20 years ago and is thought to be not uncommon in clinical practice, it has never been systematically studied. There are few publications about this condition, including no case series of more than six patients. In particular, little is known about the incidence, peak age groups, and most common locations of Terra firma-forme dermatosis. A retrospective review was conducted to identify cases of Terra firma-forme dermatosis in a single-provider practice consisting of 55% pediatric and 45% adult patients. Thirty-one patients with Terra firma-forme dermatosis were identified, including 10 who presented with Terra firma-forme dermatosis as their primary concern. Only two patients were older than 17 years. The median duration of lesions was 4 months. The most common lesion locations were the neck, ankles, and face. Before presenting to the dermatology clinic, three patients had undergone endocrine evaluations, and four had been prescribed topical corticosteroids. Terra firma-forme dermatosis is relatively common and most often occurs in children on the neck or posterior malleolus. This series exemplifies the importance of recognizing Terra firma-forme dermatosis so as to provide rapid relief for patients and avoid unnecessary tests and treatments. © 2011 Wiley Periodicals, Inc.

Constraining the physical properties of compositionally distinctive surfaces on Mars from overlapping THEMIS observations

NASA Astrophysics Data System (ADS)

Ahern, A.; Rogers, D.

2017-12-01

Better constraints on the physical properties (e.g. grain size, rock abundance, cohesion, porosity and amount of induration) of Martian surface materials can lead to greater understanding of outcrop origin (e.g. via sedimentary, effusive volcanic, pyroclastic processes). Many outcrop surfaces on Mars likely contain near-surface (<3 cm) vertical heterogeneity in physical properties due to thin sediment cover, induration, and physical weathering, that can obscure measurement of the bulk thermal conductivity of the outcrop materials just below. Fortunately, vertical heterogeneity within near-surface materials can result in unique, and possibly predictable, diurnal and seasonal temperature patterns. The KRC thermal model has been utilized in a number of previous studies to predict thermal inertia of surface materials on Mars. Here we use KRC to model surface temperatures from overlapping Mars Odyssey THEMIS surface temperature observations that span multiple seasons and local times, in order to constrain both the nature of vertical heterogeneity and the underlying outcrop thermal inertia for various spectrally distinctive outcrops on Mars. We utilize spectral observations from TES and CRISM to constrain the particle size of the uppermost surface. For this presentation, we will focus specifically on chloride-bearing units in Terra Sirenum and Meridiani Planum, as well as mafic and feldspathic bedrock locations with distinct spectral properties, yet uncertain origins, in Noachis Terra and Nili Fossae. We find that many of these surfaces exhibit variations in apparent thermal inertia with season and local time that are consistent with low thermal inertia materials overlying higher thermal inertia substrates. Work is ongoing to compare surface temperature measurements with modeled two-layer scenarios in order to constrain the top layer thickness and bottom layer thermal inertia. The information will be used to better interpret the origins of these distinctive outcrops.

Small Volcano in Terra Cimmeria

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 26 June 2002) The Science This positive relief feature (see MOLA context) in the ancient highlands of Mars appears to be a heavily eroded volcanic center. The top of this feature appears to be under attack by the erosive forces of the martian wind. Light-toned streaks are visible, trending northeast to southwest, and may be caused by scouring of the terrain, or they may be dune forms moving sand. The northeast portion of the caldera area looks as though a layer of material is being removed to expose a slightly lighter-toned surface underneath. The flanks of this feature are slightly less cratered than the surrounding terrain, which could be explained in two ways: 1) this feature may be younger than the surrounding area, and has had less time to accumulate meteorite impacts, or 2) the slopes that are observed today may be so heavily eroded that the original, cratered surfaces are now gone, exposing relatively uncratered rocks. Although most of Terra Cimmeria has low albedo, some eastern portions, such as shown in this image, demonstrate an overall lack of contrast that attests to the presence of a layer of dust mantling the surface. This dust, in part, is responsible for the muted appearance and infill of many of the craters at the northern and southern ends of this image The Story This flat-topped volcano pops out from the surface, the swirls of its ancient lava flows running down onto the ancient highlands of Mars. Its smooth top appears to be under attack by the erosive forces of the martian wind. How can you tell? Click on the image above for a close-up look. You'll see some light-toned streaks that run in a northeast-southwest direction. They are caused either by the scouring of the terrain or dunes of moving sand. Either way, the wind likely plays upon the volcano's surface. Look also for the subtle, nearly crescent shaped feature at the northeast portion of the volcano's cap. It looks as if a layer of material has been removed by the wind, exposing

Terra - 15 Years as the Earth Observing System Flagship Observatory

NASA Astrophysics Data System (ADS)

Thome, K. J.

2014-12-01

Terra marks its 15th year on orbit with an array of accomplishments and the potential to do much more. Efforts continue to extend the Terra data record to make its data more valuable by creating a record length to examine interannual variability, observe trends on the decadal scale, and gather statistics relevant to climate metrics. Continued data from Terra's complementary instruments will play a key role in creating the data record needed for scientists to develop an understanding of our climate system. Terra's suite of instruments: ASTER (contributed by the Japanese Ministry of Economy and Trade and Industry with a JPL-led US Science Team), CERES (NASA LaRC - PI), MISR (JPL - PI), MODIS (NASA GSFC), and MOPITT (sponsored by Canadian Space Agency with NCAR-led Science Team) are providing an unprecedented 81 core data products. The annual demand for Terra data remains with >120 million files distributed in 2011 and >157 million in 2012. More than 1,100 peer-reviewed publications appeared in 2012 using Terra data bringing the lifetime total >7,600. Citation numbers of 21,000 for 2012 and over 100,000 for the mission's lifetime. The power of Terra is in the high quality of the data calibration, sensor characterization, and the complementary nature of the instruments covering a range of scientific measurements as well as scales. The broad range of products enable the community to provide answers to the overarching question, "How is the Earth changing and what are the consequences for life on Earth?" Terra continues to provide data that: (1) Extend the baseline of morning-orbit collections; (2) Enable comparison of measurements acquired from past high-impact events; (3) Add value to recently-launched and soon-to-be launched missions, and upcoming field programs. Terra data continue to support monitoring and relief efforts for natural and man-made disasters that involve U.S. interests. Terra also contributes to Applications Focus Areas supporting the U.S. National

Clouds in the Northern Tempe Terra

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 2 May 2002) The Science This THEMIS visible image shows a region in northern Tempe Terra near 48o N, 75o W (285o E). Patchy water-ice clouds cover portions of the low-lying canyon at the top (north) of this image. Further south the atmosphere is clear and the knobby or 'scabby' plains that are typical of many mid-latitude regions on Mars can be seen. These plains appear to mantle and modify a pre-existing surface, burying the older cratered terrain. This mantling layer has itself been modified to produce a pitted, knobby surface. The large mesa seen in this image has unusual deposits of material that occur preferentially on the cold, north-facing slopes. These deposits are seen frequently at mid-northern and southern latitudes, and have a distinct, rounded boundary that typically occurs at approximately the same distance below the ridge crest. It has been suggested that these deposits once draped the entire surface and have since been removed from all but the north-facing slopes. The presence of water ice in these layers is a likely possibility to account for their preservation only on the colder surfaces. The south-facing slopes lack this mantling material, and show clear evidence for layering in the rock units that form the mesa. The Story This deep and murky-looking depression is in an area called 'Tempe Terra,' a lilting, alliterative name that seems almost a little too merry for this kind of terrain. If the top of the image looks a little smudgy, that's because patchy water-ice clouds hang over the low lying canyon. Further south, where the air is clear, you can see some 'scabby' plains (particularly in the high-res image, where the knobby patches of raised surface areas sort of do look like crusted-over dirt wounds). These plains cover a more ancient, cratered surface, but have been eroded away enough to form these scabby-seeming features. The large mesa in this image has some odd deposits of material on its cold, north-facing slopes. Could these

Terra Populus and DataNet Collaboration

NASA Astrophysics Data System (ADS)

Kugler, T.; Ruggles, S.; Fitch, C. A.; Clark, P. D.; Sobek, M.; Van Riper, D.

2012-12-01

Terra Populus, part of NSF's new DataNet initiative, is developing organizational and technical infrastructure to integrate, preserve, and disseminate data describing changes in the human population and environment over time. Terra Populus will incorporate large microdata and aggregate census datasets from the United States and around the world, as well as land use, land cover, climate and other environmental datasets. These data are widely dispersed, exist in a variety of data structures, have incompatible or inadequate metadata, and have incompatible geographic identifiers. Terra Populus is developing methods of integrating data from different domains and translating across data structures based on spatio-temporal linkages among data contents. The new infrastructure will enable researchers to identify and merge data from heterogeneous sources to study the relationships between human behavior and the natural world. Terra Populus will partner with data archives, data producers, and data users to create a sustainable international organization that will guarantee preservation and access over multiple decades. Terra Populus is also collaborating with the other projects in the DataNet initiative - DataONE, the DataNet Federation Consortium (DFC) and Sustainable Environment-Actionable Data (SEAD). Taken together, the four projects address aspects of the entire data lifecycle, including planning, collection, documentation, discovery, integration, curation, preservation, and collaboration; and encompass a wide range of disciplines including earth sciences, ecology, social sciences, hydrology, oceanography, and engineering. The four projects are pursuing activities to share data, tools, and expertise between pairs of projects as well as collaborating across the DataNet program on issues of cyberinfrastructure and community engagement. Topics to be addressed through program-wide collaboration include technical, organizational, and financial sustainability; semantic

Evidence for volcanism in NW Ishtar Terra, Venus

NASA Technical Reports Server (NTRS)

Gaddis, L.; Greeley, Ronald

1989-01-01

Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

Evidence for volcanism in NW Ishtar Terra, Venus

NASA Astrophysics Data System (ADS)

Gaddis, L.; Greeley, Ronald

Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred large/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-04

This image shows the western part of the dune field on the floor of Russell Crater. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 33970 Latitude: -54.3831 Longitude: 12.3712 Instrument: VIS Captured: 2009-08-11 09:20 https://photojournal.jpl.nasa.gov/catalog/PIA21802

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-09

This image shows the central part of the dune field on the floor of Russell Crater. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 34856 Latitude: -54.5757 Longitude: 12.8629 Instrument: VIS Captured: 2009-10-23 08:04 https://photojournal.jpl.nasa.gov/catalog/PIA21806

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-07-31

This image shows a slice of the floor of Russell Crater. Russell Crater is located in Noachis Terra. The spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 6354 Latitude: -54.6188 Longitude: 12.9816 Instrument: VIS Captured: 2003-05-21 14:24 https://photojournal.jpl.nasa.gov/catalog/PIA21798

Mud volcanoes of trinidad as astrobiological analogs for martian environments.

PubMed

Hosein, Riad; Haque, Shirin; Beckles, Denise M

2014-10-13

Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil's Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region.

Mud Volcanoes of Trinidad as Astrobiological Analogs for Martian Environments

PubMed Central

Hosein, Riad; Haque, Shirin; Beckles, Denise M.

2014-01-01

Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil’s Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region. PMID:25370529

Testing Multivariate Adaptive Regression Splines (MARS) as a Method of Land Cover Classification of TERRA-ASTER Satellite Images.

PubMed

Quirós, Elia; Felicísimo, Angel M; Cuartero, Aurora

2009-01-01

This work proposes a new method to classify multi-spectral satellite images based on multivariate adaptive regression splines (MARS) and compares this classification system with the more common parallelepiped and maximum likelihood (ML) methods. We apply the classification methods to the land cover classification of a test zone located in southwestern Spain. The basis of the MARS method and its associated procedures are explained in detail, and the area under the ROC curve (AUC) is compared for the three methods. The results show that the MARS method provides better results than the parallelepiped method in all cases, and it provides better results than the maximum likelihood method in 13 cases out of 17. These results demonstrate that the MARS method can be used in isolation or in combination with other methods to improve the accuracy of soil cover classification. The improvement is statistically significant according to the Wilcoxon signed rank test.

Volatile-rich Crater Interior Deposits on Mars: An Energy Balance Model of Modification

NASA Technical Reports Server (NTRS)

Russell, Patrick S.; Head, James W.; Hecht, Michael H.

2003-01-01

Several craters on Mars are partially filled by material emplaced by post-impact processes. Populations of such craters include those in the circumsouth polar cap region, in Arabia Terra, associated with the Medusae Fossae Formation, and in the northern lowlands proximal to the north polar cap. In this study, crater fill material refers to an interior mound, generally separated from the interior walls of the crater by a trough that may be continuous along the crater s circumference (i.e. a ring-shaped trough), or may only partially contact the crater walls (i.e. a crescent-shaped trough). The fill deposit is frequently off-center from the crater center and may be asymmetric, (i.e. not circular) in plan view shape. Here we test the hypothesis that asymmetries in volatile fill shape, profile, and center-location within a crater result from asymmetries in local energy balance within the crater due mainly to variation of solar insolation and radiative effects of the crater walls over the crater interior. We first focus on Korolev crater in the northern lowlands. We can then apply this model to other craters in different regions. If asymmetry in morphology and location of crater fill are consistent with radiative-dominated asymmetries in energy budget within the crater, then 1) the volatile-rich composition of the fill is supported (this process should not be effective at shaping volcanic or sedimentary deposits), and 2) the dominant factor determining the observed shape of volatile-rich crater fill is the local radiative energy budget within the crater (and erosive processes such as eolian deflation are not necessary).

Scaling the Pipe: NASA EOS Terra Data Systems at 10

NASA Technical Reports Server (NTRS)

Wolfe, Robert E.; Ramapriyan, Hampapuram K.

2010-01-01

Standard products from the five sensors on NASA's Earth Observing System's (EOS) Terra satellite are being used world-wide for earth science research and applications. This paper describes the evolution of the Terra data systems over the last decade in which the distributed systems that produce, archive and distribute high quality Terra data products were scaled by two orders of magnitude.

Sol-Terra - AN Operational Space Weather Forecasting Model Framework

NASA Astrophysics Data System (ADS)

Bisi, M. M.; Lawrence, G.; Pidgeon, A.; Reid, S.; Hapgood, M. A.; Bogdanova, Y.; Byrne, J.; Marsh, M. S.; Jackson, D.; Gibbs, M.

2015-12-01

The SOL-TERRA project is a collaboration between RHEA Tech, the Met Office, and RAL Space funded by the UK Space Agency. The goal of the SOL-TERRA project is to produce a Roadmap for a future coupled Sun-to-Earth operational space weather forecasting system covering domains from the Sun down to the magnetosphere-ionosphere-thermosphere and neutral atmosphere. The first stage of SOL-TERRA is underway and involves reviewing current models that could potentially contribute to such a system. Within a given domain, the various space weather models will be assessed how they could contribute to such a coupled system. This will be done both by reviewing peer reviewed papers, and via direct input from the model developers to provide further insight. Once the models have been reviewed then the optimal set of models for use in support of forecast-based SWE modelling will be selected, and a Roadmap for the implementation of an operational forecast-based SWE modelling framework will be prepared. The Roadmap will address the current modelling capability, knowledge gaps and further work required, and also the implementation and maintenance of the overall architecture and environment that the models will operate within. The SOL-TERRA project will engage with external stakeholders in order to ensure independently that the project remains on track to meet its original objectives. A group of key external stakeholders have been invited to provide their domain-specific expertise in reviewing the SOL-TERRA project at critical stages of Roadmap preparation; namely at the Mid-Term Review, and prior to submission of the Final Report. This stakeholder input will ensure that the SOL-TERRA Roadmap will be enhanced directly through the input of modellers and end-users. The overall goal of the SOL-TERRA project is to develop a Roadmap for an operational forecast-based SWE modelling framework with can be implemented within a larger subsequent activity. The SOL-TERRA project is supported within

New composite spectra of Mars, 0.4-5.7 μm

USGS Publications Warehouse

Erard, Stephane; Calvin, Wendy M.

1997-01-01

About 15 areas were observed in the equatorial regions of Mars by the infrared spectrometers IRS (Mariner 6 and 7) and ISM (Phobos-2). The comparison between the spectra shows a remarkable consistency between two data sets acquired 20 years apart and calibrated independently. This similarity demonstrates the accuracy of ISM calibration above 2 μm, except for a possible stray light contribution above 2.6 μm, on the order of ∼1–2% of the solar flux at 2.7 μm. Most differences in spectral shapes are related to differences in spectral/spatial resolution and viewing geometries. No important variation in surface properties is detected, except for a spot in southern Arabia Terra which has a much deeper hydration feature in IRS spectra; differences in viewing geometries and spatial resolutions do not seem to account for this difference that could result from shifting or dehydration of surface materials. Composite spectra of several types of bright and dark materials are computed by modeling the thermal emission and are completed with telescopic spectra in the visible range. Modeled reflectance in the 3.0–5.7 μm range is consistent with basalts and palagonites. The bright regions and analog palagonite spectra are different from hematite in this range, but resemble several phyllosilicates. We infer that (1) although hematite dominates the spectra in the 0.4- to 2.5-μm range, the silicate-clay host is spectrally active beyond 3 μm and can be identified from this domain; (2) phyllosilicates such as montmorillonite or smectite may be abundant components of the martian soils, although the domain below 3 μm lacks the characteristic features of the most usual terrestrial clay minerals.

Synergism of MODIS Aerosol Remote Sensing from Terra and Aqua

NASA Technical Reports Server (NTRS)

Ichoku, Charles; Kaufman, Yoram J.; Remer, Lorraine A.

2003-01-01

The MODerate-resolution Imaging Spectro-radiometer (MODIS) sensors, aboard the Earth Observing System (EOS) Terra and Aqua satellites, are showing excellent competence at measuring the global distribution and properties of aerosols. Terra and Aqua were launched on December 18, 1999 and May 4, 2002 respectively, with daytime equator crossing times of approximately 10:30 am and 1:30 pm respectively. Several aerosol parameters are retrieved at 10-km spatial resolution from MODIS daytime data over land and ocean surfaces. The parameters retrieved include: aerosol optical thickness (AOT) at 0.47, 0.55 and 0.66 micron wavelengths over land, and at 0.47, 0.55, 0.66, 0.87, 1.2, 1.6, and 2.1 microns over ocean; Angstrom exponent over land and ocean; and effective radii, and the proportion of AOT contributed by the small mode aerosols over ocean. Since the beginning of its operation, the quality of Terra-MODIS aerosol products (especially AOT) have been evaluated periodically by cross-correlation with equivalent data sets acquired by ground-based (and occasionally also airborne) sunphotometers, particularly those coordinated within the framework of the AErosol Robotic NETwork (AERONET). Terra-MODIS AOT data have been found to meet or exceed pre-launch accuracy expectations, and have been applied to various studies dealing with local, regional, and global aerosol monitoring. The results of these Terra-MODIS aerosol data validation efforts and studies have been reported in several scientific papers and conferences. Although Aqua-MODIS is still young, it is already yielding formidable aerosol data products, which are also subjected to careful periodic evaluation similar to that implemented for the Terra-MODIS products. This paper presents results of validation of Aqua-MODIS aerosol products with AERONET, as well as comparative evaluation against corresponding Terra-MODIS data. In addition, we show interesting independent and synergistic applications of MODIS aerosol data from

TERRA and the histone methyltransferase Dot1 cooperate to regulate senescence in budding yeast

PubMed Central

Wanat, Jennifer J.; Logsdon, Glennis A.; Driskill, Jordan H.; Deng, Zhong; Lieberman, Paul M.

2018-01-01

The events underlying senescence induced by critical telomere shortening are not fully understood. Here we provide evidence that TERRA, a non-coding RNA transcribed from subtelomeres, contributes to senescence in yeast lacking telomerase (tlc1Δ). Levels of TERRA expressed from multiple telomere ends appear elevated at senescence, and expression of an artificial RNA complementary to TERRA (anti-TERRA) binds TERRA in vivo and delays senescence. Anti-TERRA acts independently from several other mechanisms known to delay senescence, including those elicited by deletions of EXO1, TEL1, SAS2, and genes encoding RNase H enzymes. Further, it acts independently of the senescence delay provided by RAD52-dependent recombination. However, anti-TERRA delays senescence in a fashion epistatic to inactivation of the conserved histone methyltransferase Dot1. Dot1 associates with TERRA, and anti-TERRA disrupts this interaction in vitro and in vivo. Surprisingly, the anti-TERRA delay is independent of the C-terminal methyltransferase domain of Dot1 and instead requires only its N-terminus, which was previously found to facilitate release of telomeres from the nuclear periphery. Together, these data suggest that TERRA and Dot1 cooperate to drive senescence. PMID:29649255

Terra Harvest software architecture

NASA Astrophysics Data System (ADS)

Humeniuk, Dave; Klawon, Kevin

2012-06-01

Under the Terra Harvest Program, the DIA has the objective of developing a universal Controller for the Unattended Ground Sensor (UGS) community. The mission is to define, implement, and thoroughly document an open architecture that universally supports UGS missions, integrating disparate systems, peripherals, etc. The Controller's inherent interoperability with numerous systems enables the integration of both legacy and future UGS System (UGSS) components, while the design's open architecture supports rapid third-party development to ensure operational readiness. The successful accomplishment of these objectives by the program's Phase 3b contractors is demonstrated via integration of the companies' respective plug-'n'-play contributions that include controllers, various peripherals, such as sensors, cameras, etc., and their associated software drivers. In order to independently validate the Terra Harvest architecture, L-3 Nova Engineering, along with its partner, the University of Dayton Research Institute, is developing the Terra Harvest Open Source Environment (THOSE), a Java Virtual Machine (JVM) running on an embedded Linux Operating System. The Use Cases on which the software is developed support the full range of UGS operational scenarios such as remote sensor triggering, image capture, and data exfiltration. The Team is additionally developing an ARM microprocessor-based evaluation platform that is both energy-efficient and operationally flexible. The paper describes the overall THOSE architecture, as well as the design decisions for some of the key software components. Development process for THOSE is discussed as well.

Hydrological evolution of Atlantis basin, Sirenum Terrae, Mars. Preliminar analysis of MOC and THEMIS images.

NASA Astrophysics Data System (ADS)

de Pablo, M. A.; Márquez, A.; Centeno, J. D.

The Atlantis basin is one of the martian highlands areas where there was proposed the existence of an ancient lake during the early geological history of Mars [1] [2] [3] [4]. The existence of some morphological features inside the basin and in the surrounding area, allow to check the existence of liquid water in the past of the planet. On the other hand, other morphological features indicate the existence of snow and liquid groundwater in recent times. The detailed study of the geomorphologic features allows to make an approach to the hydrological evolution of the Atlantis basin. The study of the geomorphology of this region has been carried out by means of the analysis of MOC high resolution images obtained by the Mars Global Surveyor mission and the THEMIS images, in the visible spectrum, sent by Mars Odyssey spacecrafts. The most clearly morphological feature indicative of the existence of water in the surface of Mars in the past are the numerous channels that end into Atlantis basin from the highest terrains. In addiction to these fluvial channels, the existence of mass flow deposits is also indicative of the existence of water in the area. Some of these slumps are in the internal slopes of impact craters, but others cover huge extensions around the chaotic terrains of the studied area. The lobated ejecta deposits observed in the Atlantis basin region are indicative of the existence of groundwater (solid or liquid) [5]. Serrated reliefs and tables in the borders of the basins are indicative of the existence of a water sheet. Beneath this water sheet some deposits was formed which was eroded, due to the gradual desiccation of the basin, forming the tables and serrated reliefs. The existence of different chaotic terrains in the area implies the existence of huge amounts of water under the surface according to the different models of chaotic terrain formation [6] [7]. The existence of groundwater could be decided by the existence of collapses in the near to the

Motivational Issues of Faculty in Saudi Arabia

ERIC Educational Resources Information Center

Abdul-Cader, Akram; Anthony, Peter John

2014-01-01

This study focused on the factors that affect motivation of faculty in Saudi Arabia. It included two surveys and open-ended queries to a focus group of five academic managers and 25 faculty members of varying nationalities, rank, and institutes in Saudi Arabia. The research showed that the faculties in Saudi Arabia's highest education industry…

Results of Statewide TerraNova Testing, Fall 1998.

ERIC Educational Resources Information Center

La Marca, Paul M.

This summary provides key findings about state, district, and school level performance on the TerraNova examinations (CTB/McGraw Hill) in Nevada in 1998-1999. The TerraNova tests are used to assess students in grades 4, 8, and 10 as stipulated by Nevada law. Within this summary, a description of performance as measured by national percentile…

Pediatric retinal detachment in the Eastern Province of Saudi Arabia: experience of a tertiary care hospital.

PubMed

Cheema, Rizwan A; Al-Khars, Wajeeha; Al-Askar, Essam; Amin, Yasir M

2009-01-01

Because no previous studies have addressed the issue, we describe clinical characteristics and surgical outcome of patients with rhegmatogenous retinal detachment (RRD) in a pediatric population of the Eastern province of Saudi Arabia. We conducted a retrospective review of all consecutive cases of pediatric RRD (0-18 years) patients presenting at Dhahran Eye Specialist Hospital, a tertiary care hospital, in the Eastern Province of Saudi Arabia over a period of 3 years. Twenty patients were included in the study, accounting for 9.4% of all retinal detachment surgery cases performed over a period of 3 years (January 2006 to December 2008). The median age was 11.0 years, (range, birth to 18 years). Trauma, (45%) myopia/vitreoretinal degeneration (10%) and prior ocular surgery (25%) were significant risk factors for RRD. Proliferative vitreoretinopathy (PVR) more than grade C was present in 14/20 (70%) of cases. Most patients (15/20, 75%) were treated with pars plana vitrectomy and placement of an encircling buckle, while silicone oil or gas was used as tamponade in 13/20 (65%) patients. Surgery was successful in 17/20 (85%) cases in achieving retinal re-attachment. Visual acuity improved significantly following surgery (Mean preop 2.146 LogMAR, Mean postop 1.497 LogMAR) ( P= .014). Longer duration of RRD ( P =.007) and macular involvement ( P =.05) were associated with worse anatomical outcomes following surgery. Pediatric RRD in the Eastern province is often associated with predisposing pathology. Surgery is successful in achieving anatomical reattachment of the retina in a majority of cases with improvement of visual acuity.

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-02

This image shows individual dunes on the floor of Russell Crater, as well as larger dunes created by individual dunes coalescing . These dunes are in the western part of the dune field. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 26372 Latitude: -54.372 Longitude: 12.5481 Instrument: VIS Captured: 2007-11-24 17:16 https://photojournal.jpl.nasa.gov/catalog/PIA21800

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-07

This image shows the central part of the dune field on the floor of Russell Crater. The large ridge "bends" about 60 degrees from parallel to the right side of the image to angle towards the upper left corner. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 34232 Latitude: -54.4921 Longitude: 12.9013 Instrument: VIS Captured: 2009-09-01 23:04 https://photojournal.jpl.nasa.gov/catalog/PIA21804

Mars Researchers Rendezvous on Remote Arctic Island

NASA Technical Reports Server (NTRS)

2002-01-01

ice.

The data were captured on June 28, 2001, during the early part of the arctic summer, when sea ice becomes thinner and begins to move depending upon localized currents and winds. In winter the entire region is locked with several meters of nearly motionless sea ice, which acts as a thermodynamic barrier to the loss of heat from the comparatively warm ocean to the colder atmosphere. Summer melting of sea ice can be observed at the two large, dark regions of open water; one is present in the Jones Sound (near the top to the left of center), and another appears in the Wellington Channel (left-hand edge). A large crack caused by tidal heaving has broken the ice cover over the Parry Channel (lower right-hand corner). A substantial ice cap permanently occupies the easternmost third of the island (upper right). Surface features such as dendritic meltwater channels incised into the island's surface are apparent. The Haughton-Mars project site is located slightly to the left and above image center, in an area which appears with relatively little surface ice, near the island's inner 'elbow.'

The images were acquired during Terra orbit 8132 and cover an area of about 334 kilometers x 229 kilometers. They utilize data from blocks 27 to 31 within World Reference System-2 path 42.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Live-cell imaging reveals the dynamics and function of single-telomere TERRA molecules in cancer cells.

PubMed

Avogaro, Laura; Querido, Emmanuelle; Dalachi, Myriam; Jantsch, Michael F; Chartrand, Pascal; Cusanelli, Emilio

2018-04-16

Telomeres cap the ends of eukaryotic chromosomes, protecting them from degradation and erroneous recombination events which may lead to genome instability. Telomeres are transcribed giving rise to telomeric repeat-containing RNAs, called TERRA. The TERRA long noncoding RNAs have been proposed to play important roles in telomere biology, including heterochromatin formation and telomere length homeostasis. While TERRA RNAs are predominantly nuclear and localize at telomeres, little is known about the dynamics and function of TERRA molecules expressed from individual telomeres. Herein, we developed an assay to image endogenous TERRA molecules expressed from a single telomere in living human cancer cells. We show that single-telomere TERRA can be detected as TERRA RNA single particles which freely diffuse within the nucleus. Furthermore, TERRA molecules aggregate forming TERRA clusters. Three-dimensional size distribution and single particle tracking analyses revealed distinct sizes and dynamics for TERRA RNA single particles and clusters. Simultaneous time lapse confocal imaging of TERRA particles and telomeres showed that TERRA clusters transiently co-localize with telomeres. Finally, we used chemically modified antisense oligonucleotides to deplete TERRA molecules expressed from a single telomere. Single-telomere TERRA depletion resulted in increased DNA damage at telomeres and elsewhere in the genome. These results suggest that single-telomere TERRA transcripts participate in the maintenance of genomic integrity in human cancer cells.

TERRA Promotes Telomere Shortening through Exonuclease 1–Mediated Resection of Chromosome Ends

PubMed Central

Pfeiffer, Verena; Lingner, Joachim

2012-01-01

The long noncoding telomeric repeat containing RNA (TERRA) is expressed at chromosome ends. TERRA upregulation upon experimental manipulation or in ICF (immunodeficiency, centromeric instability, facial anomalies) patients correlates with short telomeres. To study the mechanism of telomere length control by TERRA in Saccharomyces cerevisiae, we mapped the transcriptional start site of TERRA at telomere 1L and inserted a doxycycline regulatable promoter upstream. Induction of TERRA transcription led to telomere shortening of 1L but not of other chromosome ends. TERRA interacts with the Exo1-inhibiting Ku70/80 complex, and deletion of EXO1 but not MRE11 fully suppressed the TERRA–mediated short telomere phenotype in presence and absence of telomerase. Thus TERRA transcription facilitates the 5′-3′ nuclease activity of Exo1 at chromosome ends, providing a means to regulate the telomere shortening rate. Thereby, telomere transcription can regulate cellular lifespan through modulation of chromosome end processing activities. PMID:22719262

Remnants of Lost Geology

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site]

In eastern Arabia Terra, remnants of a once vast layered terrain are evident as isolated buttes, mesas, and deeply-filled craters. The origin of the presumed sediments that created the layers is unknown, but those same sediments, now eroded, may be the source of the thick mantle of dust that covers much of Arabia Terra today.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 20.5, Longitude 50 East (310 West). 19 meter/pixel resolution.

Day And Night In Terra Meridiani

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

Released 11 June 2004 This pair of images shows part of the Terra Meridiani region.

Day/Night Infrared Pairs

The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top.

Infrared image interpretation

Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark.

Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images.

Image information: IR instrument. Latitude 1.3, Longitude 0.5 East (359.5 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released

Hydrogeology of Basins on Mars

NASA Technical Reports Server (NTRS)

Arvidson, Raymond E.

2001-01-01

This document summarizes the work accomplished under NASA Grant NAG5-3870. Emphasis was put on the development of the FIDO rover, a prototype for the twin-Mers which will be operating on the surface of Mars in 2004, specifically the primary work was the analysis of FIDO field trials. The grantees also analyzed VIKING Lander 1 XRFS and Pathfinder APXS data. Results show that the Viking site chemistry is consistent with an andesite, and the Pathfinder site is consistent with a basaltic andesite. The grantees also worked to demonstrate the capability to simulate annealing methods to apply to the inversion of remote sensing data. They performed an initial analyses of Sojourner engineering telemetry and imaging data. They performed initial analyses of Viking Lander Stereo Images, and of Hematite deposits in Terra Meridiani. They also acquired and analyzed the New Goldstone radar data.

Abstracts of the Annual Meeting of Planetary Geologic Mappers, Flagstaff, AZ, 2008

NASA Technical Reports Server (NTRS)

Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L. (Editor); Kelley, Michael S. (Editor)

2008-01-01

Topics discussed include: Merging of the USGS Atlas of Mercury 1:5,000,000 Geologic Series; Geologic Mapping of the V-36 Thetis Regio Quadrangle: 2008 Progress Report; Structural Maps of the V-17 Beta Regio Quadrangle, Venus; Geologic Mapping of Isabella Quadrangle (V-50) and Helen Planitia, Venus; Renewed Mapping of the Nepthys Mons Quadrangle (V-54), Venus; Mapping the Sedna-Lavinia Region of Venus; Geologic Mapping of the Guinevere Planitia Quadrangle of Venus; Geological Mapping of Fortuna Tessera (V-2): Venus and Earth's Archean Process Comparisons; Geological Mapping of the North Polar Region of Venus (V-1 Snegurochka Planitia): Significant Problems and Comparisons to the Earth's Archean; Venus Quadrangle Geological Mapping: Use of Geoscience Data Visualization Systems in Mapping and Training; Geologic Map of the V-1 Snegurochka Planitia Quadrangle: Progress Report; The Fredegonde (V-57) Quadrangle, Venus: Characterization of the Venus Midlands; Formation and Evolution of Lakshmi Planum (V-7), Venus: Assessment of Models using Observations from Geological Mapping; Geologic Map of the Meskhent Tessera Quadrangle (V-3), Venus: Evidence for Early Formation and Preservation of Regional Topography; Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus: A Progress Report; Geology of the Lachesis Tessera Quadrangle (V-18), Venus; Geologic Mapping of the Juno Chasma Quadrangle, Venus: Establishing the Relation Between Rifting and Volcanism; Geologic Mapping of V-19, V-28, and V-53; Lunar Geologic Mapping Program: 2008 Update; Geologic Mapping of the Marius Quadrangle, the Moon; Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars: Introductory Report; New Geologic Map of the Argyre Region of Mars; Geologic Evolution of the Martian Highlands: MTMs -20002, -20007, -25002, and -25007; Mapping Hesperia Planum, Mars; Geologic Mapping of the Meridiani Region, Mars; Geology of Holden Crater and the Holden and Ladon Multi

Analysis of Organic Molecules Extracted from Mars Analogues and Influence of Their Mineralogy Using N-Methyl-N-(tert-butyldimethylsilyl)Trifluoroacetamide Derivatization Coupled with Gas Chromatography Mass Spectrometry in Preparation for the Sample Analysis at Mars Derivatization Experiment on the Mars Science Laboratory Mission

NASA Technical Reports Server (NTRS)

Stalport, F.; Glavin, D. P.; Eigenbrode, J. L.; Bish, D.; Blake, D.; Coll, P.; Szopa, C.; Buch, A.; McAdam, A.; Dworkin, J. P.;

Health Education in Saudi Arabia

PubMed Central

Al-Hashem, Anwar

2016-01-01

This article provides a historical overview of the evolution of health education in Saudi Arabia. It outlines milestones in the development of the health education profession and traces the roles of various health sectors and their achievements in the health education field. Additionally, this review seeks to describe the status of health education professionals in Saudi Arabia. PMID:27606106

Is Ishtar Terra a thickened basaltic crust?

NASA Technical Reports Server (NTRS)

Arkani-Hamed, Jafar

1992-01-01

The mountain belts of Ishtar Terra and the surrounding tesserae are interpreted as compressional regions. The gravity and surface topography of western Ishtar Terra suggest a thick crust of 60-110 km that results from crustal thickening through tectonic processes. Underthrusting was proposed for the regions along Danu Montes and Itzpapalotl Tessera. Crustal thickening was suggested for the entire Ishtar Terra. In this study, three lithospheric models with total thicknesses of 40.75 and 120 km and initial crustal thicknesses of 3.9 and 18 km are examined. These models could be produced by partial melting and chemical differentiation in the upper mantle of a colder, an Earth-like, and a hotter Venus having temperatures of respectively 1300 C, 1400 C, and 1500 C at the base of their thermal boundary layers associated with mantle convection. The effects of basalt-granulite-eclogite transformation (BGET) on the surface topography of a thickening basaltic crust is investigated adopting the experimental phase diagram and density variations through the phase transformation.

The Influence of Mineralogy on Recovering Organic Acids from Mars Analogue Materials Using the One-Pot Derivatization Experiment on the Sample Analysis at Mars(SAM) Instrument Suite

NASA Technical Reports Server (NTRS)

Stalport, Fabien; Glavin, Daniel P.; Eigenbrode, J. L.; Bish, D.; Blake, D.; Coll, P.; Szopa, C.; Buch, A.; McAdam, A.; Dworkin, J. P.;

Regional Studies of Highland-Lowland Age Differences Across the Mars Crustal Dichotomy Boundary

NASA Technical Reports Server (NTRS)

Frey, H. V.; DeSoto, G. E.; Lazrus, R. M.

2005-01-01

Regional differences in crater retention ages (CRAs) across the Mars dichotomy boundary are compared to the global highland-lowland age difference previously determined from visible and buried impact basins based on MOLA-derived Quasi-Circular Depressions (QCDs). Here Western Arabia (WA) is compared with Ismenius Lacus (IL). We find the buried lowlands in the two regions have total CRAs essentially identical to the global average. Even more intriguing, the WA cratered terrain appears to have a CRA like that of the adjacent buried lowlands,

Multiple Episodes of Recent Gully Activity Indicated by Gully Fan Stratigraphy in Eastern Promethei Terra, Mars.

NASA Astrophysics Data System (ADS)

Schon, S.; Head, J.; Fassett, C.

2008-09-01

Introduction Gullies are considered among the youngest geomorphic features on Mars based upon their stratigraphic relationships, superposition on steep slopes and distinctive morphology in unconsolidated sediment. Multiple formation hypotheses have been proposed, which can be divided into three broad classes: entirely dry mechanisms (e.g., [1,2]), wet mechanisms invoking groundwater or ground ice (e.g., [3,4]) and wet mechanisms invoking surficial meltwater (e.g., [5,6,7,8]). It has been difficult to differentiate between these hypotheses based upon past observations and it remains possible that gullies are polygenetic landforms. This study presents stratigraphic relationships in the depositional fan of a crater wall gully system that suggest: (1) multiple episodes of alluvial fan-style deposition, (2) very recent depositional activity that is younger than a newly recognized rayed crater, and (3) surficial snowmelt as the most likely source of these multiple episodes of recent gully activity. Gully-Fan Stratigraphy In Eastern Promethei Terra an ~5 km-diameter crater is observed with a well-developed gully system (Fig. 1) and several smaller gullies in its northnortheast wall. The large gully system (composed of a small western gully and larger eastern gully) shows evidence for incision into the crater wall country rock and has multiple contributory sub-alcoves and channels. The depositional fan associated with this gully system is bounded on its western side by a small arcuate ridge swell that is not observed on the eastern side of the fan. This ridge is interpreted as a moraine-like structure that may have bounded a glacially-formed depression into which the fan is deposited [8]. Similar depressions with bounding ridges are commonly observed in this latitude band (~30-50°S) in association with deeply incised gully alcoves [9,10,11]. This gully fan is composed of multiple lobes with distinct lobe contacts, incised channels, and cut-andfill deposits - all features

Euripus Mons - Landform Evolution and Climate Constraints in Promethei Terra

NASA Astrophysics Data System (ADS)

van Gasselt, Stephan; Kim, Jungrack; Baik, Hyun-Seob

2016-04-01

The Promethei Terra region of Mars exhibits a variety of geomorphic landforms indicative of ice-assisted creep of debris and ice, similar to features and processes found at the Martian dichotomy boundary in Deuteronilus, Protonilus and Nilosyrtis Mensae. Despite only little doubt about the fact that ice played an integral role in the formation of these features, it is still disputed if these features were formed by glacial processes, requiring precipitation of ice and snow and exhibiting glacial deformation and basal sliding, or if these landforms are a product of periglacial denudation and subject to different deformation regimes. As information about past climate conditions on Mars is sparse, the proper assessment of landform types today allows to put constraints on their environmental conditions in the past. Due to limited knowledge about the internal physical and thermal structure of these landforms, it remains impossible to unambiguously determine their origin [1]. A variety of geomorphic and model-based indicators need to be taken into account when putting constraints on their history and when trying to reconstruct their evolution. For selected features on Mars it has been shown by SHARAD radar observations that the ice content might be relatively high [2], and that some of them might be composed of pure ice, protected from sublimation by a thin debris cover. One of such examples, Euripus Mons, is a 80 km remnant feature with an associated circumferential talus deposit that shows indicators for deformation by downslope movement, i.e. debris apron morphology. Recent modelling assuming glacial deformation helped to reconstruct some internal structural properties [3]. Despite these attempts, Euripus Mons shows clear geomorphic signatures of classical periglacial denudation which do not fit into the concept of glacial-only evolution. Denudation rates as well as ages are similar to those reported from other locations on Mars for which hyperarid climate conditions

Comparação de modelos para o cálculo de perturbações orbitais devidas à maré terrestre

NASA Astrophysics Data System (ADS)

Vieira Pinto, J.; Vilhena de Moraes, R.

2003-08-01

Aplicações recentes de satélites artificiais com finalidades geodinâmicas requerem órbitas determinadas com bastante precisão. Em particular marés terrestres influenciam o potencial terrestre causando perturbações adicionais no movimento de satélites artificiais, as quais tem sido medidas por diversos processos. A atração exercida pela lua e pelo sol sobre a terra produz deslocamentos elásticos em seu interior e uma protuberância em sua superfície. O resultado é uma pequena variação na distribuição da massa na terra, consequentemente no geopotencial. As perturbações nos elementos orbitais de satélites artificiais terrestres devidas a maré terrestre podem ser estudadas a partir das equações de Lagrange, considerando-se um conveniente potencial. Por outro lado, como tem sido feito pelo IERS, as mudanças induzidas pela maré terrestre no geopotencial podem ser convenientemente modeladas como variações nos coeficientes Cnm e Snm do geopotencial. As duas teorias ainda não foram comparados para um mesmo satélite. Neste trabalho são apresentadas e comparadas as variações de longo período e seculares nas perturbações orbitais devidas à maré terrestre, calculadas por um modelo simples, o de Kozai, e pelo modelo do IERS. Resultados preliminares mostram, para os satélites SCD2 e CBERS1, e para a Lua em movimento elíptico e precessionando, as perturbações seculares no argumento do perigeu e na longitude do nodo ascendente.

10 years of Terra Outreach over the Internet

NASA Astrophysics Data System (ADS)

Yuen, K.; Riebeek, H.; Chambers, L. H.

2009-12-01

1 Author Yuen, Karen JPL (818) 393-7716 2 Author Riebeek, Holli Sigma Space Corporation (department) at NASA Goddard Space Flight Center (Institution), Greenbelt, Maryland 3 Author Chambers, Lin NASA Abstract: Since launch, Terra has returned about 195 gigabytes (level 0) of data per day or 1 terabyte every 5 days. Few outlets were able to accommodate and quickly share that amount of information as well as the Internet. To honor the 10-year anniversary of the launch of Terra, we would like to highlight the education and outreach efforts of the Terra mission on the Internet and its reach to the science attentive public. The Internet or web has been the primary way of delivering Terra content to different groups- from formal and informal education to general public outreach. Through the years, many different web-based projects have been developed, and they were of service to a growing population of the science attentive public. One of Terra’s original EPO activities was the Earth Observatory. It was initially dedicated to telling the remote sensing story of Terra, but quickly grew to include science and imagery from other sensors. The web site allowed for collaboration across NASA centers, universities and other organizations by exchanging and sharing of story ideas, news and images. The award winning Earth Observatory helped pave the way for the more recently funded development of the Climate Change website. With its specific focus on climate change studies, once again, Terra stories and images are shared with an even more specific audience base. During the last 10 years, Terra as a mission has captured the imagination of the public through its visually stunning and artistically arresting images. With its five instruments of complementary but unique capabilities, the mission gave the world not just pretty pictures, but scientific data-based images. The world was able to see from space everything from calving icebergs to volcanic eruption plumes and the eye of a

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-10

This image shows the central part of the dune field on the floor of Russell Crater, including the large dune ridge. Comparing this image to yesterday's you will see a significant difference in appearance. This image was collected at a higher incidence angle, so the sun is at a different angle to the surface. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 39723 Latitude: -54.4434 Longitude: 13.0526 Instrument: VIS Captured: 2010-11-28 01:47 https://photojournal.jpl.nasa.gov/catalog/PIA21807

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-03

This image shows the western section of the large sand ridge on the floor of Russell Crater. This is also the northern extent of the dune field. The crest of the large ridge runs from lower right to upper left. Smaller dune ridges intersect the large ridge perpendicular to the crest. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 26659 Latitude: -54.0179 Longitude: 12.8638 Instrument: VIS Captured: 2007-12-18 08:26 https://photojournal.jpl.nasa.gov/catalog/PIA21801

MGS Approach Image - 352.2o W longitude

NASA Technical Reports Server (NTRS)

1997-01-01

The bright area at the center of this view of Mars taken by the MGS/MOC is called Arabia. It contains some of the brightest ground on Mars, thought to be especially deep or fresh dust deposits. Syrtis Major, the dark feature curving north-south near the center edge of the planet, is devoid of large amounts of dust, probably because sand moves for frequently there and kicks up the dust into the martian air where it can be transported away. The dark 'splotches' near the middle top of the image are small sand dune fields trapped in the depressions of the Protonilus and Nilosyrtis 'fretted terrain' (a zone of valleys formed by tectonic fracturing and subsequent erosion). In the lower portion of the image is Terra Sabaea, a heavily cratered area near regions where major dust storms occur. The light, semicircular indentation is the 480 km diameter crater Schiaparelli.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Middle Jurassic Planktonic Foraminifer in Saudi Arabia - a new biostratigraphical marker for the J30 maximum flooding surface in the Middle East

NASA Astrophysics Data System (ADS)

Kaminski, Michael; Babalola, Lameed; Chan, Septriandi

2017-04-01

Planktonic foraminifera are found in marls of the lowermost portion of Unit D5 of the middle Dhruma Formation exposed west of Riyadh, Saudi Arabia. This lower part of this unit corresponds to the J30 Maximum Flooding Surface of Sharland et al., (2001) and has been correlated to the lower Bathonian Clydocromphalus ammonite zone by Énay et al. (2009) (= the Procerites aurigerus ammonite zone in the global scale). This lithological subunit can be correlated throughout the Middle East, from Saudi Arabia to Oman and Syria. Our discovery is the first report of planktonic foraminifera in the Middle Jurassic (lower Bathonian) of Saudi Arabia. Two genera are recognized: a low-spired species identified as Globuligerina sp., and a high-spired form assigned to Conoglobigerina sp. The planktonic foraminifera comprise approximately 5-10% of the assemblage at the studied locality, and are found within a benthic foraminiferal assemblage consisting of a mixture of smaller agglutinated species (Nautiloculina, Haplophragmoides, Ammomarginulina, Sculptobaculites), and calcareous species (nodosariids, opthalmidiids, epistominids, polymorphinids, and spirillinids) without any larger foraminifera. The assemblage is indicative of open-marine shelf conditions, and represents a typical Middle Jurassic benthic foraminiferal fauna from a marly carbonate substrate. The calcareous benthic foraminifera are of small dimensions, indicating that oligotrophic environmental conditions prevailed at the time of deposition of the unit. The discovery of planktonic foraminifera in the D5 Unit of the Dhruma Formation provides a new correlation tool for recognizing the J30 maximum flooding surface in the Middle East. Sharland, P.R., Archer, R., Casey, D.M., Davies, R.B., Hall, S.H., Heward, A.P., Horbury, A.D. & Simmons, M.D. 2001. Arabian Plate Sequence Stratigraphy. GeoArabia Special Publication, 2, 371 pp. Énay, R., Mangold, C., Alméras, Y. & Hughes, G.W. 2009. The Wadi ad Dawasir "delta", central

Multitemporal Observations of Sugarcane by TerraSAR-X Images

PubMed Central

Baghdadi, Nicolas; Cresson, Rémi; Todoroff, Pierre; Moinet, Soizic

2010-01-01

The objective of this study is to investigate the potential of TerraSAR-X (X-band) in monitoring sugarcane growth on Reunion Island (located in the Indian Ocean). Multi-temporal TerraSAR data acquired at various incidence angles (17°, 31°, 37°, 47°, 58°) and polarizations (HH, HV, VV) were analyzed in order to study the behaviour of SAR (synthetic aperture radar) signal as a function of sugarcane height and NDVI (Normalized Difference Vegetation Index). The potential of TerraSAR for mapping the sugarcane harvest was also studied. Radar signal increased quickly with crop height until a threshold height, which depended on polarization and incidence angle. Beyond this threshold, the signal increased only slightly, remained constant, or even decreased. The threshold height is slightly higher with cross polarization and higher incidence angles (47° in comparison with 17° and 31°). Results also showed that the co-polarizations channels (HH and VV) were well correlated. High correlation between SAR signal and NDVI calculated from SPOT-4/5 images was observed. TerraSAR data showed that after strong rains the soil contribution to the backscattering of sugarcane fields can be important for canes with heights of terminal visible dewlap (htvd) less than 50 cm (total cane heights around 155 cm). This increase in radar signal after strong rains could involve an ambiguity between young and mature canes. Indeed, the radar signal on TerraSAR images acquired in wet soil conditions could be of the same order for fields recently harvested and mature sugarcane fields, making difficult the detection of cuts. Finally, TerraSAR data at high spatial resolution were shown to be useful for monitoring sugarcane harvest when the fields are of small size or when the cut is spread out in time. The comparison between incidence angles of 17°, 37° and 58° shows that 37° is more suitable to monitor the sugarcane harvest. The cut is easily detectable on TerraSAR images for data acquired

Deserts in the Deluge: TerraPopulus and Big Human-Environment Data.

PubMed

Manson, S M; Kugler, T A; Haynes, D

2016-01-01

Terra Populus, or TerraPop, is a cyberinfrastructure project that integrates, preserves, and disseminates massive data collections describing characteristics of the human population and environment over the last six decades. TerraPop has made a number of GIScience advances in the handling of big spatial data to make information interoperable between formats and across scientific communities. In this paper, we describe challenges of these data, or 'deserts in the deluge' of data, that are common to spatial big data more broadly, and explore computational solutions specific to microdata, raster, and vector data models.

Model of formation of Ishtar Terra, Venus

NASA Astrophysics Data System (ADS)

Ansan, V.; Vergely, P.; Masson, Ph.

1996-08-01

For more than a decade, the radar mapping of Venus' surface has revealed that it results from a complex volcanic and tectonic history, especially in the northern latitudes. Ishtar Terra (0°E-62°E) consists of a high plateau, Lakshmi Planum, surrounded by highlands, Freyja Montes to the north and Maxwell Montes to the east. The latter is the highest relief of Venus, standing more than 10 km in elevation. The high resolution of Magellan radar images (120-300 m) allows us to interpret them in terms of tectonics and propose a model of formation for the central part of Ishtar Terra. The detailed tectonic interpretations are based on detailed structural and geologic cartography. The geologic history of Ishtar Terra resulted from two distinct, opposite tectonic stages with an important, transitional volcanic activity. First, Lakshmi Planum, the oldest part of Ishtar Terra is an extensive and complexly fractured plateau that can be compared to a terrestrial craton. Then the plateau is partially covered by fluid lava flows that may be similar to Deccan traps, in India. Second, after the extensional deformation of Lakshmi Planum and its volcanic activity, Freyja and Maxwell Montes formed by WSW-ENE horizontal crustal shortening. The latter produced a series of NNW-SSE parallel, sinuous, folds and imbricated structures that overlapped Lakshmi Planum westward. So these mountain belts have the same structural characteristics as terrestrial fold-and-thrust belts. These mountain belts also display evidence of a late volcanic stage and a subsequent period of relaxation that created grabens parallel to the highland trend, especially in Maxwell Montes.

EOS Terra: Mission Status Constellation MOWG

NASA Technical Reports Server (NTRS)

Mantziaras, Dimitrios

2016-01-01

This EOS Terra Mission Status Constellation MOWG will discuss mission summary; spacecraft subsystems summary, recent and planned activities; inclination adjust maneuvers, conjunction history, propellant usage and lifetime estimate; and end of mission plan.

The Western Noachis Terra Chloride Deposits: An Improved Characterization of the Proposed Human Exploration Zone

NASA Astrophysics Data System (ADS)

Hill, J. R.; Plaut, J. J.; Christensen, P. R.

2016-12-01

At the First Landing Site and Exploration Zone Workshop for Human Missions to the Surface of Mars (Oct 27-30, 2015, Houston, TX), planetary scientists, students and members of the public proposed forty-seven sites that meet the engineering requirements for a human mission and would also allow astronauts to investigate important scientific questions while on the surface. The chloride deposits in western Noachis Terra at -37.2°N, 350.5°E were proposed as a potential exploration zone due to their proximity to craters containing glacier-like forms and imperfectly-formed concentric crater fill. The high astrobiological preservation potential of the chloride deposits exposed on the surface would allow astronauts to investigate the past habitability of a well-preserved Noachian fluvial system, while the subsurface ice features suggest astronauts would have relatively easy access to enough water to meet the requirements of NASA's current baseline mission architecture. Since the workshop, the proposed exploration zone has been further characterized using additional datasets, as well as new data collected by the Mars Reconnaissance Orbiter as part of the exploration zone data acquisition effort organized by NASA's Human Landing Sites Study (HLS2) team. First, SHARAD radar data were used to constrain the subsurface structure of the imperfectly-formed concentric crater fill within the two large craters, which makes a more accurate assessment of the potential subsurface water ice resources possible. Second, newly acquired HiRISE images were used to better assess the traversability of the terrain between the habitation zone and the primary resource and science regions-of-interest (ROIs). And third, the exploration zone was shifted in order to place the central landing site closer to potential subsurface water ice resources. Although this would require crews to travel further to investigate the chloride deposits, it reduces the distance between the subsurface water ice

Telomere Length Determines TERRA and R-Loop Regulation through the Cell Cycle.

PubMed

Graf, Marco; Bonetti, Diego; Lockhart, Arianna; Serhal, Kamar; Kellner, Vanessa; Maicher, André; Jolivet, Pascale; Teixeira, Maria Teresa; Luke, Brian

2017-06-29

Maintenance of a minimal telomere length is essential to prevent cellular senescence. When critically short telomeres arise in the absence of telomerase, they can be repaired by homology-directed repair (HDR) to prevent premature senescence onset. It is unclear why specifically the shortest telomeres are targeted for HDR. We demonstrate that the non-coding RNA TERRA accumulates as HDR-promoting RNA-DNA hybrids (R-loops) preferentially at very short telomeres. The increased level of TERRA and R-loops, exclusively at short telomeres, is due to a local defect in RNA degradation by the Rat1 and RNase H2 nucleases, respectively. Consequently, the coordination of TERRA degradation with telomere replication is altered at shortened telomeres. R-loop persistence at short telomeres contributes to activation of the DNA damage response (DDR) and promotes recruitment of the Rad51 recombinase. Thus, the telomere length-dependent regulation of TERRA and TERRA R-loops is a critical determinant of the rate of replicative senescence. Copyright © 2017 Elsevier Inc. All rights reserved.

Bringing Terra Science to the People: 10 years of education and public outreach

NASA Astrophysics Data System (ADS)

Riebeek, H.; Chambers, L. H.; Yuen, K.; Herring, D.

2009-12-01

The default image on Apple's iPhone is a blue, white, green and tan globe: the Blue Marble. The iconic image was produced using Terra data as part of the mission's education and public outreach efforts. As far-reaching and innovative as Terra science has been over the past decade, Terra education and public outreach efforts have been equally successful. This talk will provide an overview of Terra's crosscutting education and public outreach projects, which have reached into educational facilities—classrooms, museums, and science centers, across the Internet, and into everyday life. The Earth Observatory web site was the first web site designed for the public that told the unified story of what we can learn about our planet from all space-based platforms. Initially conceived as part of Terra mission outreach in 1999, the web site has won five Webby awards, the highest recognition a web site can receive. The Visible Earth image gallery is a catalogue of NASA Earth imagery that receives more than one million page views per month. The NEO (NASA Earth Observations) web site and WMS (web mapping service) tool serves global data sets to museums and science centers across the world. Terra educational products, including the My NASA Data web service and the Students' Cloud Observations Online (S'COOL) project, bring Terra data into the classroom. Both projects target multiple grade levels, ranging from elementary school to graduate school. S'COOL uses student observations of clouds to help validate Terra data. Students and their parents have puzzled over weekly "Where on Earth" geography quizzes published on line. Perhaps the most difficult group to reach is the large segment of the public that does not seek out science information online or in a science museum or classroom. To reach these people, EarthSky produced a series of podcasts and radio broadcasts that brought Terra science to more than 30 million people in 2009. Terra imagery, including the Blue Marble, have

Arecibo radar imagery of Mars: II. Chryse-Xanthe, polar caps, and other regions

NASA Astrophysics Data System (ADS)

Harmon, John K.; Nolan, Michael C.

2017-01-01

We conclude our radar imaging survey of Mars, which maps spatial variations in depolarized radar reflectivity using Arecibo S-band (λ12.6 cm) observations from 2005-2012. Whereas our earlier paper (Harmon et al., 2012, Arecibo radar imagery of Mars: the major volcanic provinces. Icarus 220, 990-1030) covered the volcanic regions of Tharsis, Elysium, and Amazonis, this paper includes non-volcanic regions where hydrologic and impact processes can be the dominant resurfacing agents affecting radar backscatter. Many of the more prominent and interesting radar-bright features outside the major volcanic provinces are located in and around Chryse Planitia and Xanthe Terra. These features are identified with: a basin in northeast Lunae Planum containing the combined deposits from Maja Vallis and Ganges Catena outflows; channel outwash plains in western and southern Chryse basin; plateaus bordering chasma/chaos zones, where surface modification may have resulted from hydrologic action associated with incipient chaos formation; and some bright-ejecta craters in Chryse basin, of a type otherwise rare on Mars. Dark-halo craters have also been identified in Chryse and elsewhere that are similar to those seen in the volcanic provinces. Although the cratered highlands are relatively radar-bland, they do exhibit some bright depolarized features; these include eroded crater rims, several unusual ejecta flows and impact melts, and terrain-softened plains. The rims of large impact basins (Hellas, Argyre, Isidis) show a variety of radar-bright features provisionally identified with massif slopes, erosion sediments, eroded pyroclastics, impact melts, and glacial deposits. The interiors of these basins are largely radar-dark, which is consistent with coverage by rock-free sediments. Tempe Terra and Acheron Fossae show bright features possibly associated with rift volcanism or eroded tectonic structures, and northwest Tempe Terra shows one very bright feature associated with glacial or

Well-Preserved Impact Ejecta and Impact Melt-Rich Deposits in Terra Sabaea

NASA Image and Video Library

2017-01-12

This image of a well-preserved unnamed elliptical crater in Terra Sabaea, is illustrative of the complexity of ejecta deposits forming as a by-product of the impact process that shapes much of the surface of Mars. Here we see a portion of the western ejecta deposits emanating from a 10-kilometer impact crater that occurs within the wall of a larger, 60-kilometer-wide crater. In the central part is a lobe-shaped portion of the ejecta blanket from the smaller crater. The crater is elliptical not because of an angled (oblique) impact, but because it occurred on the steep slopes of the wall of a larger crater. This caused it to be truncated along the slope and elongated perpendicular to the slope. As a result, any impact melt from the smaller crater would have preferentially deposited down slope and towards the floor of the larger crater (towards the west). Within this deposit, we can see fine-scale morphological features in the form of a dense network of small ridges and pits. These crater-related pitted materials are consistent with volatile-rich impact melt-bearing deposits seen in some of the best-preserved craters on Mars (e.g., Zumba, Zunil, etc.). These deposits formed immediately after the impact event, and their discernible presence relate to the preservation state of the crater. This image is an attempt to visualize the complex formation and emplacement history of these enigmatic deposits formed by this elliptical crater and to understand its degradation history. http://photojournal.jpl.nasa.gov/catalog/PIA13078

Early Childhood Education in Saudi Arabia: Report

ERIC Educational Resources Information Center

Rabaah, Alqassem; Doaa, Dashash; Asma, Alzahrani

2016-01-01

This paper reviewed the development of early childhood education (ECE) in Saudi Arabia and its strengths and weaknesses. The paper discusses the contextual background of Saudi Arabia, including its geography, demographics, social system, economy, political system and religion. In addition, the paper investigated the education system at large in…

Climate, migration, and the local food security context: Introducing Terra Populus

PubMed Central

Schlak, Allison M.; Kugler, Tracy A.

2016-01-01

Studies investigating the connection between environmental factors and migration are difficult to execute because they require the integration of microdata and spatial information. In this article, we introduce the novel, publically available data extraction system Terra Populus (TerraPop), which was designed to facilitate population-environment studies. We showcase the use of TerraPop by exploring variations in the climate-migration association in Burkina Faso and Senegal based on differences in the local food security context. Food security was approximated using anthropometric indicators of child stunting and wasting derived from Demographic and Health Surveys (DHS) and linked to the TerraPop extract of climate and migration information. We find that an increase in heat waves was associated with a decrease in international migration from Burkina Faso, while excessive precipitation increased international moves from Senegal. Significant interactions reveal that the adverse effects of heat waves and droughts are strongly amplified in highly food insecure Senegalese departments. PMID:27974863

Surface Albedo/BRDF Parameters (Terra/Aqua MODIS)

DOE Data Explorer

Trishchenko, Alexander

2008-01-15

Spatially and temporally complete surface spectral albedo/BRDF products over the ARM SGP area were generated using data from two Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on Terra and Aqua satellites. A landcover-based fitting (LBF) algorithm is developed to derive the BRDF model parameters and albedo product (Luo et al., 2004a). The approach employs a landcover map and multi-day clearsky composites of directional surface reflectance. The landcover map is derived from the Landsat TM 30-meter data set (Trishchenko et al., 2004a), and the surface reflectances are from MODIS 500m-resolution 8-day composite products (MOD09/MYD09). The MOD09/MYD09 data are re-arranged into 10-day intervals for compatibility with other satellite products, such as those from the NOVA/AVHRR and SPOT/VGT sensors. The LBF method increases the success rate of the BRDF fitting process and enables more accurate monitoring of surface temporal changes during periods of rapid spring vegetation green-up and autumn leaf-fall, as well as changes due to agricultural practices and snowcover variations (Luo et al., 2004b, Trishchenko et al., 2004b). Albedo/BRDF products for MODIS on Terra and MODIS on Aqua, as well as for Terra/Aqua combined dataset, are generated at 500m spatial resolution and every 10-day since March 2000 (Terra) and July 2002 (Aqua and combined), respectively. The purpose for the latter product is to obtain a more comprehensive dataset that takes advantages of multi-sensor observations (Trishchenko et al., 2002). To fill data gaps due to cloud presence, various interpolation procedures are applied based on a multi-year observation database and referring to results from other locations with similar landcover property. Special seasonal smoothing procedure is also applied to further remove outliers and artifacts in data series.

NASA's Terra Spacecraft Eyes Smoke Plumes from Massive Rim Fire Near Yosemite

Atmospheric Science Data Center

2014-05-15

article title:  NASA's Terra Spacecraft Eyes Smoke Plumes from Massive Rim Fire Near Yosemite   ... on NASA's Terra spacecraft, showing extensive, brownish smoke. The imaged area measures 236 by 215 miles (380 by 346 kilometers). ...

Development of Higher Education in Saudi Arabia.

ERIC Educational Resources Information Center

Saleh, Mahmoud Abdullah

1986-01-01

The history of higher education in Saudi Arabia is outlined, especially as it relates to Islamic religion and educational philosophy, and its rapid growth is chronicled. These aspects are examined: Saudi students studying abroad, foreign students in Saudi Arabia, women's education, the Ministry of Higher Education's role, and financing. (MSE)

Thermal Performance of Capillary Pumped Loops Onboard Terra Spacecraft

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Butler, Charles D.; Swanson, Theodore; Thies, Diane

2004-01-01

The Terra spacecraft is the flagship of NASA's Earth Science Enterprise. It provides global data on the state of atmosphere, land and oceans, as well as their interactions with solar radiation and one another. Three Terra instruments utilize Capillary Pumped Heat Transport System (CPHTS) for temperature control: Each CPHTS, consisting of two capillary pumped loops (CPLs) and several heat pipes and electrical heaters, is designed for instrument heat loads ranging from 25W to 264W. The working fluid is ammonia. Since the launch of the Terra spacecraft, each CPHTS has been providing a stable interface temperature specified by the instrument under all modes of spacecraft and instrument operations. The ability to change the CPHTS operating temperature upon demand while in service has also extended the useful life of one instrument. This paper describes the design and on-orbit performance of the CPHTS thermal systems.

Investigating Mars: Russell Crater

NASA Image and Video Library

2017-08-08

This image shows part of the dune field just south of the large sand ridge - which is visible on the very top of the image. There is a huge range of dune sizes on the floor of Russell Crater. In this image the small sizes are at the bottom of the image and transition to larger dunes at the top. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 34544 Latitude: -54.6035 Longitude: 12.6071 Instrument: VIS Captured: 2009-09-27 15:35 https://photojournal.jpl.nasa.gov/catalog/PIA21805

76 FR 28973 - Terra-Gen Dixie Valley, LLC; Order on Rehearing and Accepting Tariff Filing, Subject to...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-19

.... Clustering and Effective Date i. Terra-Gen Tariff Provisions 15. Terra-Gen proposes provisions to address clustering of transmission system impact studies, consistent with the guidance provided in the January 14... on how Terra-Gen may cluster studies.\\22\\ Terra-Gen's proposed clustering provisions provide, among...

Saudi Arabia: Background and U.S. Relations

DTIC Science & Technology

2009-12-16

Arabia from 1989 to 1992. Tabassum Zakaria, “Analysis—Saudi smile likely for Bush on oil plea, not more,” Reuters, May 12, 2008. Saudi Arabia...2009. 24 Tabassum Zakaria, “Analysis—Saudi smile likely for Bush on oil plea, not more,” Reuters, May 12, 2008. 25 U.S. Department of State

The Martian, Part 2: Mawrth Valles

NASA Image and Video Library

2015-10-13

All this week, the THEMIS Image of the Day is following on the real Mars the path taken by fictional astronaut Mark Watney, stranded on the Red Planet in the book and movie, The Martian. Today's image shows part of Mawrth Valles, a channel carved by giant floods billions of years ago. The highlands lying to the south and west of the channel are under consideration as a potential landing site for NASA's Mars 2020 rover. Remote-sensing observations from orbit show widespread exposures of clay minerals, indicating alteration by water early in Martian history. These might preserve traces of ancient life, if there was any. For astronaut Mark Watney, driving in a pressurized and solar-powered rover vehicle, Mawrth Valles offers a gentle slope and an easy-to-follow route up from Acidalia's low-lying plains into the Arabia Terra highlands. At this point in his journey, he has driven about 750 kilometers (470 miles). Orbit Number: 38563 Latitude: 24.4297 Longitude: 341.726 Instrument: VIS Captured: 2010-08-24 14:56 http://photojournal.jpl.nasa.gov/catalog/PIA19797

Mars exploration advances: Missions to Mars - Mars base

NASA Technical Reports Server (NTRS)

Dejarnette, Fred R.; Mckay, Christopher P.

1992-01-01

An overview is presented of Mars missions and related planning with attention given to four mission architectures in the light of significant limitations. Planned unpiloted missions are discussed including the Mars Orbital Mapping Mission, the Mars Rover Sample Return, the Mars Aeronomy Orbiter, and the Mars Environmental Survey. General features relevant to the missions are mentioned including launch opportunities, manned-mission phases, and propulsion options. The four mission architectures are set forth and are made up of: (1) the Mars-exploration infrastructures; (2) science emphasis for the moon and Mars; (3) the moon to stay and Mars exploration; and (4) space resource utilization. The possibility of robotic missions to the moon and Mars is touched upon and are concluded to be possible by the end of the century. The ramifications of a Mars base are discussed with specific reference to habitability and base activities, and the human missions are shown to require a heavy-lift launcher and either chemical/aerobrake or nuclear-thermal propulsion system.

Color Infrared, Terra Sirenum

NASA Image and Video Library

2002-03-01

This is the first high-resolution color infrared image taken of Mars. The image was constructed using three of the ten infrared filters on the thermal emission imaging system of NASA Mars Odyssey spacecraft.

Audiology and speech-language pathology practice in Saudi Arabia.

PubMed

Alanazi, Ahmad A

2017-01-01

Audiology and speech-language pathology (SLP) are relatively new professions in Saudi Arabia. The idea of establishing new audiology and SLP programs in some education facilities has become popular across Saudi Arabia; yet, only four undergraduate and graduate programs are currently available. This study aimed to explore the fields of audiology and SLP in Saudi Arabia, obtain demography of audiologists and Speech-language pathologists (SLPs), understand their current practices, and identify their perspective on what both professions need to improve. A cross-sectional mixed methods study design was used to address the aim of this study. Two online surveys were prepared and distributed to reach a large number of audiologists and SLPs. Both surveys consisted of close- and open-ended questions and primarily focused on three categories demography, audiology or SLP practices, and audiologists' or SLPs' perspective on their professions in Saudi Arabia. A total of 23 audiologists and 37 SLPs completed the surveys (age range = 21-50 years). The majority of respondents were from Riyadh with different academic qualifications and working experiences. Various practices were noticed among audiologists and SLPs who mainly worked in hospitals. Several suggestions regarding the development of audiology and SLP education and practice in Saudi Arabia are discussed. This study provides useful information about audiology and SLP education and practices in Saudi Arabia. Collaborative work between stakeholders to achieve high-quality educational and practical standards is critical. National database, clinical guidelines and policies should be developed, employed, and supervised. Further research is needed to improve education and practice of both professions in Saudi Arabia.

Microbial mats in playa lakes and other saline habitats: Early Mars analog?

NASA Technical Reports Server (NTRS)

Bauld, John

1989-01-01

Microbial mats are cohesive benthic microbial communities which inhabit various Terra (Earth-based) environments including the marine littoral and both permanent and ephemeral (playa) saline lakes. Certain geomorphological features of Mars, such as the Margaritifer Sinus, were interpreted as ancient, dried playa lakes, presumably formed before or during the transition to the present Mars climate. Studies of modern Terran examples suggest that microbial mats on early Mars would have had the capacity to survive and propagate under environmental constraints that would have included irregularly fluctuating regimes of water activity and high ultraviolet flux. Assuming that such microbial communities did indeed inhabit early Mars, their detection during the Mars Rover Sample Return (MRSR) mission depends upon the presence of features diagnostic of the prior existence of these communities or their component microbes or, as an aid to choosing suitable landing, local exploration or sampling sites, geomorphological, sedimentological or chemical features characteristic of their playa lake habitats. Examination of modern Terran playas (e.g., the Lake Eyre basin) shows that these features span several orders of magnitude in size. While stromatolites are commonly centimeter-meter scale features, bioherms or fields of individuals may extend to larger scales. Preservation of organic matter (mats and microbes) would be favored in topographic lows such as channels or ponds of high salinity, particularly those receiving silica-rich groundwaters. These areas are likely to be located near former zones of groundwater emergence and/or where flood channels entered the paleo-playa. Fossil playa systems which may aid in assessing the applicability of this particular Mars analog include the Cambrian Observatory Hill Beds of the Officer Basin and the Eocene Wilkins Peak Member of the Green River Formation.

Connecting Students across Universities in Saudi Arabia

ERIC Educational Resources Information Center

Al-Jarf, Reima Sado

2005-01-01

The present study reports results of an experiment in which the author and her students at King Saud University (KSU) in Riyadh, Saudi Arabia shared an online grammar course with a professor and his students at Umm Al-Qura University (UQU) in Makkah, Saudi Arabia using www.makkahelearning.net. The experiment proved to be a total failure. Factors…

Thunderstorm distribution and frequency in Saudi Arabia

NASA Astrophysics Data System (ADS)

Shwehdi, M. H.

2005-09-01

A new average annual thunder day map for Saudi Arabia is presented. Based on this map, the distribution of thunderstorms over Saudi Arabia is analysed in terms of the factors related to the lightning performance of transmission lines such as thunderstorm days per year (Td/yr). Lightning activity continues for the present to be represented by thunderstorm frequency, which is routinely recorded at meteorological observation sites. Thunderstorm occurrence at a particular location is usually expressed as the number of days in a calendar year when thunder was heard, averaged over several years. This paper examines thunderstorm days in different areas of Saudi Arabia and specifically those areas where lightning strikes are more frequent; for this purpose, the software ArcGIS is used to produce contour maps which demonstrate areas of concern in Saudi Arabia in the period 1985-2003. Establishing the annual and seasonal Td/yr for Saudi Arabia enables transmission and distribution line engineers to calculate and better design a lightning protection system. Maps of thunder days/year (Td/yr) were constructed on the basis of the database records available on lightning incidence in Saudi Arabia at the Presidency of Meteorology and Environment (PME) (http://www.pme.gov.sa/). Annual thunderstorms are most frequent over the southwestern parts of the country, and generally decrease towards the west and east. Due to its low latitude and less temporal change, the west coast of the Red Sea recorded the lowest Td/yr. A secondary maximum Td/yr is apparent in the southeast to central part of the country. Thunderstorm frequency does not, in general, appear to vary in any consistent way with rainfall. There appears to be no evidence of any widespread temporal trend in thunderstorm frequency. The southern region in general, and especially the cities of Abha, Taif and Al-Baha, has shown greater numbers of thunderstorm days all year round. Similarly, this variation did show higher frequency

Terra-Kleen Response Group, Inc. Solvent Extraction Technology Rapid Commercialization Initiative Report

EPA Science Inventory

Terra-Kleen Response Group Inc. (Terra-Kleen), has commercialized a solvent extraction technology that uses a proprietary extraction solvent to transfer organic constituents from soil to a liquid phase in a batch process at ambient temperatures. The proprietary solvent has a rel...

Identification and visualisation of possible ancient ocean shoreline on Mars using submeter-resolution Digital Terrain Models

NASA Astrophysics Data System (ADS)

Świąder, Andrzej

2014-12-01

Digital Terrain Models (DTMs) produced from stereoscopic, submeter-resolution High Resolution Imaging Science Experiment (HiRISE) imagery provide a solid basis for all morphometric analyses of the surface of Mars. In view of the fact that a more effective use of DTMs is hindered by complicated and time-consuming manual handling, the automated process provided by specialists of the Ames Intelligent Robotics Group (NASA), Ames Stereo Pipeline, constitutes a good alternative. Four DTMs, covering the global dichotomy boundary between the southern highlands and northern lowlands along the line of the presumable Arabia shoreline, were produced and analysed. One of them included forms that are likely to be indicative of an oceanic basin that extended across the lowland northern hemisphere of Mars in the geological past. The high resolution DTMs obtained were used in the process of landscape visualisation.

Atmospheric PCB concentrations at Terra Nova Bay, Antarctica.

PubMed

Gambaro, Andrea; Manodori, Laura; Zangrando, Roberta; Cincinelli, Alessandra; Capodaglio, Gabriele; Cescon, Paolo

2005-12-15

Concentrations of gas-phase polychlorobiphenyls (PCBs) were studied over an austral summer at a site in Terra Nova Bay, Antarctica. Gas-phase concentrations of individual PCB congeners in the atmosphere of Terra Nova Bay ranged from below the detection limit to 0.25 pg m(-3), with a mean concentration of sigmaPCB of 1.06 pg m(-3). The PCB profile was dominated by lower-chlorinated PCB congeners; in fact >78% of the total PCB content was due to congeners with 1-4 chlorine atoms and only about 10% with 5-7 chlorines, whereas higher-chlorinated PCB congeners were below detection limits. The mean sigmaPCB concentration obtained in this study were lower than those reported in previous Antarctic studies. Temporal concentration profiles of sigmaPCB do not correspond to seasonal temperature changes. In consideration of the low PCB concentrations observed, the studies with the wind roses, the regression between In P(PCB) and T(-1), and the distribution of congeners, we can hypothesize that PCB local source contributions are not very important, whereas long-distance transport is the prevalent factor bringing PCBs to Terra Nova Bay.

Preliminary Operational Results of the TDRSS Onboard Navigation System (TONS) for the Terra Mission

NASA Technical Reports Server (NTRS)

Gramling, Cheryl; Lorah, John; Santoro, Ernest; Work, Kevin; Chambers, Robert; Bauer, Frank H. (Technical Monitor)

2000-01-01

The Earth Observing System Terra spacecraft was launched on December 18, 1999, to provide data for the characterization of the terrestrial and oceanic surfaces, clouds, radiation, aerosols, and radiative balance. The Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (ONS) (TONS) flying on Terra provides the spacecraft with an operational real-time navigation solution. TONS is a passive system that makes judicious use of Terra's communication and computer subsystems. An objective of the ONS developed by NASA's Goddard Space Flight Center (GSFC) Guidance, Navigation and Control Center is to provide autonomous navigation with minimal power, weight, and volume impact on the user spacecraft. TONS relies on extracting tracking measurements onboard from a TDRSS forward-link communication signal and processing these measurements in an onboard extended Kalman filter to estimate Terra's current state. Terra is the first NASA low Earth orbiting mission to fly autonomous navigation which produces accurate results. The science orbital accuracy requirements for Terra are 150 meters (m) (3sigma) per axis with a goal of 5m (1 sigma) RSS which TONS is expected to meet. The TONS solutions are telemetered in real-time to the mission scientists along with their science data for immediate processing. Once set in the operational mode, TONS eliminates the need for ground orbit determination and allows for a smooth flow from the spacecraft telemetry to planning products for the mission team. This paper will present the preliminary results of the operational TONS solution available from Terra.

A synthesis of Martian aqueous mineralogy after 1 Mars year of observations from the Mars Reconnaissance Orbiter

USGS Publications Warehouse

Murchie, S.L.; Mustard, J.F.; Ehlmann, B.L.; Milliken, R.E.; Bishop, J.L.; McKeown, N.K.; Noe Dobrea, E.Z.; Seelos, F.P.; Buczkowski, D.L.; Wiseman, S.M.; Arvidson, R. E.; Wray, J.J.; Swayze, G.; Clark, R.N.; Des Marais, D.J.; McEwen, A.S.; Bibring, J.-P.

2009-01-01

Martian aqueous mineral deposits have been examined and characterized using data acquired during Mars Reconnaissance Orbiter's (MRO) primary science phase, including Compact Reconnaissance Imaging Spectrometer for Mars hyperspectral images covering the 0.4-3.9 ??m wavelength range, coordinated with higher-spatial resolution HiRISE and Context Imager images. MRO's new high-resolution measurements, combined with earlier data from Thermal Emission Spectrometer; Thermal Emission Imaging System; and Observatoire pour la Min??ralogie, L'Eau, les Glaces et l'Activiti?? on Mars Express, indicate that aqueous minerals are both diverse and widespread on the Martian surface. The aqueous minerals occur in 9-10 classes of deposits characterized by distinct mineral assemblages, morphologies, and geologic settings. Phyllosilicates occur in several settings: in compositionally layered blankets hundreds of meters thick, superposed on eroded Noachian terrains; in lower layers of intracrater depositional fans; in layers with potential chlorides in sediments on intercrater plains; and as thousands of deep exposures in craters and escarpments. Carbonate-bearing rocks form a thin unit surrounding the Isidis basin. Hydrated silica occurs with hydrated sulfates in thin stratified deposits surrounding Valles Marineris. Hydrated sulfates also occur together with crystalline ferric minerals in thick, layered deposits in Terra Meridiani and in Valles Marineris and together with kaolinite in deposits that partially infill some highland craters. In this paper we describe each of the classes of deposits, review hypotheses for their origins, identify new questions posed by existing measurements, and consider their implications for ancient habitable environments. On the basis of current data, two to five classes of Noachian-aged deposits containing phyllosilicates and carbonates may have formed in aqueous environments with pH and water activities suitable for life. Copyright 2009 by the American

Outflow Stream from Relatively Recent Martian Lake

NASA Image and Video Library

2016-09-15

Streamlined forms and channel bars in this Martian valley resulted from the outflow of a lake hundreds of millions years more recently than an era of Martian lakes previously confirmed, according to 2016 findings. This excerpt from an image taken by the Context Camera on NASA's Mars Reconnaissance Orbiter covers an area about 8 miles (13 kilometers) wide in the northern Arabia Terra region of Mars. The flow direction was generally northward (toward the top of this image). The channel breached a water-filled basin identified as "B" in a hydrologic-modeling map at PIA20839 and flowed toward a larger basin, informally called "Heart Lake," about 50 miles (80 kilometers) to the northwest. Researchers estimate this stream and the lakes it linked held water at some time in the range of 2 billion to 3 billion years ago. That is several hundred million to about 1 billion years later than better-known ancient lake environments on Mars, such as those documented by NASA's Curiosity rover mission. The later wet period came after it is generally thought that most of Mars' original atmosphere had been lost and most of the remaining water on the planet had frozen. Seasonal melting may have fed this stream. This is a portion of Context Camera image B18_016815_2151. http://photojournal.jpl.nasa.gov/catalog/PIA20837

Retrieval of Aerosol Properties from MODIS Terra, MODIS Aqua, and VIIRS SNPP: Calibration Focus

NASA Technical Reports Server (NTRS)

Levy, Robert C.; Mattoo, Shana; Sawyer, Virginia; Kleidman, Richard; Patadia, Falguni; Zhou, Yaping; Gupta, Pawan; Shi, Yingxi; Remer, Lorraine; Holz, Robert

2016-01-01

MODIS-DT Collection 6 - Aqua/Terra level 2, 3; entire record processed - "Trending" issues reduced - Still a 15% or 0.02 Terra vs Aqua offset. - Terra/Aqua convergence improved with C6+, but bias remains. - Other calibration efforts yield mixed results. VIIRS-­-DT in development - VIIRS is similar, yet different then MODIS - With 50% wider swath, VIIRS has daily coverage - Ensures algorithm consistency with MODIS. - Currently: 20% NPP vs Aqua offset over ocean. - Only small bias (%) over land (2012-­-2016) - Can VIIRS/MODIS create aerosol CDR? Calibration for MODIS - VIIRS continues to fundamentally important. It's not just Terra, or just Aqua, or just NPP-­-VIIRS, I really want to push synergistic calibration.

Ancient deltas on Mars: outstanding targets for martian habitability?

NASA Astrophysics Data System (ADS)

Gupta, S.; Fawdon, P.; Grindrod, P. M.; Balme, M. R.; Hauber, E.; Warner, N. H.; Muller, J. P.

2014-12-01

The identification of putative ancient deltaic sedimentary systems on Mars has been both exciting and controversial. Our excitement is elicted by the potential provided by deltas as evidence for standing bodies of water associated with the deltas, and the resulting implications for both the ancient climate of Mars and ancient habitability. The controversy stems from how confident can we be in the identification of ancient deltaic systems from orbital data, and how robust are our assertions about the habitability potential of such settings. Delta systems in particular are key astrobiological targets because at their distal toes fine-grained sediment (ie., clays) settle from suspension in a lower energy setting and they are commonly characterised by high rates of sedimentation. This leads to high preservation potential of biosignatures. Targeting of future Mars rovers to investigate deltaic landing sites requires better understanding of these issues to reduce exploration risk. In this presentation, we describe the key criteria that enable us to make robust interpretations of deltaic stratigraphy and constrain delta evolution for martian systems. In particular, the past 10 years has seen in a revolution in our process understanding of terrestrial delta systems through a combination of field, experimental and numerical modelling studies. Analysis of martian deltas has much to gain from these results. We go on to consider why deltaic systems offer potential as astrobiological target paleoenvironments. We use the exhumed delta system (Hypanis delta system) at the termination of Hypanis Vallis, 11.8°N, 314.96°E as a case example. This system, situated in Xanthe Terra, comprises layered sedimentary rocks with an overall multi-lobate geometry and associated inverted channel networks. The Hypanis 'delta' is a proposed landing site for the ExoMars rover and also for the NASA 2020 mission.

Terra Firma-Forme Dermatosis in Singaporean Patients: The "Alcohol Wipe" Sign.

PubMed

Oh, Choon Chiat; Oon, Hazel H; Ng, See Ket; Tee, Shang Ian; Jhingan, Anjali; Chong, Wei-Sheng

2016-01-01

The term terra firma-forme dermatosis arises from the Latin phrase terra firma , meaning dry land (dirt), thus implying dirt-like dermatosis. The authors highlight five cases of patients with terra firma-forme dermatosis presenting to our dermatology center between 2012 and 2013. All patients presented to the dermatologist for persistent reticulated brown patches on the skin. These patients ranged in age from 6 to 22 years. All patients had tried various cleansing soaps and agents but were unable to remove the patches. The condition was cosmetically unacceptable to the patients and parents. Clinically, these patients had reticulated brown patches. Rubbing 70% isopropyl alcohol wipes on the affected areas demonstrated clearance of the brown pigmented patches in all cases. The diagnosis of terra firma-forme dermatosis (TFFD) was confirmed by forceful rubbing with a gauze pad immersed in 70% isopropyl alcohol or ethyl alcohol. Patients should be reassured about the benign nature of TFFD and educated about the cleaning procedure. Recognition of this condition can assist physicians in making a diagnosis and therapy with a simple alcohol wipe, preventing further unnecessary tests for patients.

Health technology assessment in Saudi Arabia.

PubMed

Al-Aqeel, Sinaa

2018-05-16

The Saudi government, similar to any other government, is committed to making public spending more efficient, using resources more effectively, and limiting waste. Health technology assessment (HTA) is a tool that informs policy and decision makers regarding the formulation of safe and effective policies that are patient-focused and help to achieve efficiency when allocating limited health-care resources. Areas covered: After a brief description of HTA in the international context, this review provides a brief introduction to Saudi Arabia's health-care system, followed by a delineation of the decision maker(s) and influencers and the decision-making process for pricing and reimbursement. The article then discusses the current status of HTA in Saudi Arabia and proposes four strategic objectives that can form the first step in the development of a formal HTA process. Expert commentary: In Saudi Arabia, facilitators for incorporating HTA into the decision-making process exist. Future local research is needed to guide the implementation of full HTA.

Sample Return from Ancient Hydrothermal Springs

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy Z.

2008-01-01

Hydrothermal spring deposits on Mars would make excellent candidates for sample return. Molecular phylogeny suggests that that life on Earth may have arisen in hydrothermal settings [1-3], and on Mars, such settings not only would have supplied energy-rich waters in which martian life may have evolved [4-7] but also would have provided warm, liquid water to martian life forms as the climate became colder and drier [8]. Since silica, sulfates, and clays associated with hydrothermal settings are known to preserve geochemical and morphological remains of ancient terrestrial life [9-11], such settings on Mars might similarly preserve evidence of martian life. Finally, because formation of hydrothermal springs includes surface and subsurface processes, martian spring deposits would offer the potential to assess astrobiological potential and hydrological history in a variety of settings, including surface mineralized terraces, associated stream deposits, and subsurface environments where organic remains may have been well protected from oxidation. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data [12-14]. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel, and based on these new data, we have interpreted several features in Vernal Crater, Arabia Terra as ancient hydrothermal springs [15, 16].

Earth Observing System (EOS) Terra Spacecraft 120 Volt Power Subsystem: Requirements, Development and Implementation

NASA Technical Reports Server (NTRS)

Keys, Denney J.

2000-01-01

Built by the Lockheed-Martin Corporation, the Earth Observing System (EOS) TERRA spacecraft represents the first orbiting application of a 120 Vdc high voltage spacecraft electrical power system implemented by the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC). The EOS TERRA spacecraft's launch provided a major contribution to the NASA Mission to Planet Earth program while incorporating many state of the art electrical power system technologies to achieve its mission goals. The EOS TERRA spacecraft was designed around five state-of-the-art scientific instrument packages designed to monitor key parameters associated with the earth's climate. The development focus of the TERRA electrical power system (EPS) resulted from a need for high power distribution to the EOS TERRA spacecraft subsystems and instruments and minimizing mass and parasitic losses. Also important as a design goal of the EPS was maintaining tight regulation on voltage and achieving low conducted bus noise characteristics. This paper outlines the major requirements for the EPS as well as the resulting hardware implementation approach adopted to meet the demands of the EOS TERRA low earth orbit mission. The selected orbit, based on scientific needs, to achieve the EOS TERRA mission goals is a sun-synchronous circular 98.2degree inclination Low Earth Orbit (LEO) with a near circular average altitude of 705 kilometers. The nominal spacecraft orbit is approximately 99 minutes with an average eclipse period of about 34 minutes. The scientific goal of the selected orbit is to maintain a repeated 10:30 a.m. +/- 15 minute descending equatorial crossing which provides a fairly clear view of the earth's surface and relatively low cloud interference for the instrument observation measurements. The major EOS TERRA EPS design requirements are single fault tolerant, average orbit power delivery of 2, 530 watts with a defined minimum lifetime of five years (EOL). To meet

Rub al Khali, Arabia

NASA Image and Video Library

2008-08-08

NASA Terra spacecraft shows the Rub al Khali, one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula; it includes parts of Oman, United Arab Emirates, and Yemen.

Pharmacy Education in Jordan, Saudi Arabia, and Kuwait

PubMed Central

Al-Wazaify, Mayyada; Matowe, Lloyd; Albsoul-Younes, Abla; Al-Omran, Ola A.

2006-01-01

The practice of pharmacy, as well as pharmacy education, varies significantly throughout the world. In Jordan, Kuwait, and Saudi Arabia, the profession of pharmacy appears to be on the ascendance. This is demonstrated by an increase in the number of pharmacy schools and the number of pharmacy graduates from pharmacy programs. One of the reasons pharmacy is on the ascendance in these countries is government commitment to fund and support competitive, well-run pharmacy programs. In this report we describe pharmacy education in 3 Middle East countries: Jordan, Kuwait, and Saudi Arabia. All 3 countries offer bachelor of pharmacy (BPharm) degrees. In addition, 2 universities in Jordan and 1 in Saudi Arabia offer PharmD degree programs. The teaching methods in all 3 countries combine traditional didactic lecturing and problem-based learning. Faculties of pharmacy in all 3 countries are well staffed and offer competitive remuneration. All 3 countries have a policy of providing scholarships to local students for postgraduate training abroad. The majority of students in Jordan and Kuwait are female, while the ratio of male to female students in Saudi Arabia is even. Students’ attitudes towards learning are generally positive in all 3 countries. In Saudi Arabia and Kuwait, most pharmacy graduates work in the public sector, while in Jordan, the majority work in the private sector. PMID:17136159

Aqua and Terra MODIS RSB Calibration Comparison Using BRDF Modeled Reflectance

NASA Technical Reports Server (NTRS)

Chang, Tiejun; Xiong, Xiaoxiong; Angal, Amit; Wu, Aisheng; Geng, Xu

2017-01-01

The inter-comparison of MODIS reflective solar bands onboard Aqua and Terra is very important for assessment of each instrument's calibration. One of the limitations is the lack of simultaneous nadir overpasses. Their measurements over a selected Earth view target have significant differences in solar and view angles, which magnify the effects of atmospheric scattering and Bidirectional Reflectance Distribution Function (BRDF). In this work, an intercomparison technique is formulated after correction for site's BRDF and atmospheric effects. The reflectance measurements over Libya desert sites 1, 2, and 4 from both the Aqua and Terra MODIS are regressed to a BRDF model with an adjustable coefficient accounting for calibration difference. The ratio between Aqua and Terra reflectance measurements are derived for bands 1 to 9 and the results from different sites show good agreement. For year 2003, the ratios are in the range of 0.985 to1.010 for band 1 to 9. Band 3 shows the lowest ratio 0.985 and band 1 shows the highest ratio 1.010. For the year 2014, the ratio ranges from approximately 0.983 for bands 2 and 1.012 for band 8. The BRDF corrected reflectance for the two instruments are also derived for every year from 2003 to 2014 for stability assessment. Bands 1 and 2 show greater than 1 differences between the two instruments. Aqua bands 1 and 2 show downward trends while Terra bands 1 and 2 show upward trends. Bands 8 and 9 of both Aqua and Terra show large variations of reflectance measurement over time.

Sleep Medicine in Saudi Arabia

PubMed Central

Almeneessier, Aljohara S.; BaHammam, Ahmed S.

2017-01-01

The practice of sleep medicine in Saudi Arabia began in the mid to late 1990s. Since its establishment, this specialty has grown, and the number of specialists has increased. Based on the available data, sleep disorders are prevalent among the Saudi population, and the demand for sleep medicine services is expected to increase significantly. Currently, two training programs are providing structured training and certification in sleep medicine in this country. Recently, clear guidelines for accrediting sleep medicine specialists and technologists were approved. Nevertheless, numerous obstacles hamper the progress of this specialty, including the lack of trained technicians, specialists, and funding. Increasing the awareness of sleep disorders and their serious consequences among health care workers, health care authorities, and insurance companies is another challenge. Future plans should address the medical educational system at all levels to demonstrate the importance of early detection and the treatment of sleep disorders. This review discusses the current position of and barriers to sleep medicine practice and education in Saudi Arabia. Citation: Almeneessier AS, BaHammam AS. Sleep medicine in Saudi Arabia. J Clin Sleep Med. 2017;13(4):641–645. PMID:28212693

Terra Cimmeria - False Color

NASA Image and Video Library

2016-10-11

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. Today's false color image shows dust devil tracks (dark blue linear feature) in Terra Cimmeria. Orbit Number: 43463 Latitude: -53.1551 Longitude: 125.069 Instrument: VIS Captured: 2011-10-01 23:55 http://photojournal.jpl.nasa.gov/catalog/PIA21009

Ares 3 and The Martian

NASA Image and Video Library

2015-03-11

This image from NASA Mars Reconnaissance Orbiter shows a region of Acidalia Planitia which is covered by dense fields of boulders up to several meters high. In "The Martian" by Andy Weir (watch for the movie in late 2015), stranded astronaut Mark Watney spends most of his time at the "Ares 3" site in southern Acidalia Planitia. The book describes Acidalia as flat and easy to drive over; he even drives to the Pathfinder landing site and back. This region of Mars is actually far more diverse, interesting, and hazardous to drive over than depicted in the novel. These two images (this observation and ESP_019783_2115) are close to the Ares 3 landing site as shown in a map at the front of the novel, and shows many mounds, perhaps ancient volcanoes resulting from lava-water interaction or eruption of muddy sediments. Much of Acidalia Planitia is covered by dense fields of boulders up to several meters high that would be difficult to drive around. There are also fissures associated with giant polygons, with steep rocky slopes that would be impassable. There are elongated fields of dense secondary craters where the surface is extremely rough at scales near the size of the rover. When our hero travels into Arabia Terra it is described as much rockier than Acidalia, but the the opposite is generally true: much of Arabia is dust mantled and smooth at the scale of a rover. People commonly assume that smooth at large scales (kilometers) means smooth at small scales ( meters to tens of meters). Often on Mars, the exact opposite is seen: large flat low areas are more wind-scoured, removing fine materials and leaving rocks and eroded bedrock. http://photojournal.jpl.nasa.gov/catalog/PIA19306

On the Stability of Liquid Water on Present Day Mars

NASA Technical Reports Server (NTRS)

Haberle, Robert M.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

The mean annual surface pressure and temperature on present day Mars do not allow for the long term stability of liquid water on the surface. However, theoretical arguments have been advanced that suggest liquid water could form in transient events even though it would not be in equilibrium with the environment. Using a Mars General Circulation Model, we calculate where and for how long the surface pressure and surface temperature meet the minimum requirements for this metastability of liquid water. These requirements are that the pressure and temperature must be above the triple point of water, but below its boiling point. We find that there are five regions on Mars where these requirements are periodically satisfied: in the near equatorial regions of Amazonis, Arabia, and Elysium, and in the Hellas and Argyre impact basins. Whether liquid water ever forms in these regions depends on the availability of ice and heat, and on the evaporation rate. The latter is poorly understood for low pressure CO2 environments, but is likely to be so high that melting occurs rarely, if at all. However, in the relatively recent past, surface pressures may have been higher than they are today perhaps by as much as a factor of 2 or 3. Under these circumstances melting would have been easier to achieve. We plan to undertake laboratory experiments to better understand the potential for melting in low pressure environments.

TerraLook: GIS-Ready Time-Series of Satellite Imagery for Monitoring Change

USGS Publications Warehouse

,

2008-01-01

TerraLook is a joint project of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) with a goal of providing satellite images that anyone can use to see changes in the Earth's surface over time. Each TerraLook product is a user-specified collection of satellite images selected from imagery archived at the USGS Earth Resources Observation and Science (EROS) Center. Images are bundled with standards-compliant metadata, a world file, and an outline of each image's ground footprint, enabling their use in geographic information systems (GIS), image processing software, and Web mapping applications. TerraLook images are available through the USGS Global Visualization Viewer (http://glovis.usgs.gov).

Concentrating Solar Power Projects in Saudi Arabia | Concentrating Solar

Science.gov Websites

belowâ€"alphabetical by project name. You can browse a project profile by clicking on the project Power | NREL Saudi Arabia Concentrating solar power (CSP) projects in Saudi Arabia are listed

Neurology Research in Saudi Arabia: Urgent call for action.

PubMed

Algahtani, Hussein; Shirah, Bader; Boker, Faisal; Algamdi, Albaraa; Alkahtani, Abdulah

2017-08-01

Research activities in Saudi Arabia are promoted at the governmental and institutional levels. However, the output and quality of research conducted in the field of neurology has not yet been measured quantitatively. This study therefore aimed to analyse neurology-related publications from Saudi Arabia. This study was conducted in January 2016. A systematic search using the PubMed ® search engine (National Library of Medicine, Bethesda, Maryland, USA) was conducted to identify all neurology-related articles published from Saudi Arabia between January 1996 and December 2015. A total of 1,292 neurology-related publications were identified. Neurology research increased linearly with time, with most publications originating from Riyadh (67%) and the university sector (≈47%). However, most neurology-related articles were published in journals which had an impact factor of <1 (55%). Neurology research in Saudi Arabia has increased substantially over the last 20 years. However, as most articles were published in low-impact journals, the quality of research remains inadequate and should be improved. It is important that an official research culture be established in both governmental and private universities as well as colleges and health institutions in Saudi Arabia. The formation of clinical academic departments staffed by research experts is recommended to ensure the quality of neurology research output.

Update: Saudi Arabia.

ERIC Educational Resources Information Center

McGregor, Joy; Nydell, Margaret

A guide for persons planning on living in or relocating to Saudi Arabia for extended periods of time, this book features information on such topics as entry requirements, transportation, money matters, housing, schools, and insurance. The guide's contents include the following sections: (1) an overview; (2) before leaving; (3) on arrival; (4)…

From Soup to Nuts: How Terra has enabled the growth of NASA Earth science communication

NASA Astrophysics Data System (ADS)

Ward, K.; Carlowicz, M. J.; Allen, J.; Voiland, A.; Przyborski, P.

2014-12-01

The birth of NASA's Earth Observatory website in 1999 closely mirrored the launch of Terra and over the years its growth has paralleled that of the Earth Observing System (EOS) program. With the launch of Terra, NASA gained an extraordinary platform that not only promised new science capabilities but gave us the data and imagery for telling the stories behind the science. The Earth Observatory Group was founded to communicate these stories to the public. We will present how we have used the capabilities of all the Terra instruments over the past 15 years to expand the public's knowledge of NASA Earth science. The ever-increasing quantity and quality of Terra data, combined with technological improvements to data availability and services has allowed the Earth Observatory and, as a result, the greater science-aware media, to greatly expand the visibility of NASA data and imagery. We will offer thoughts on best practices in using these multi-faceted instruments for public communication and we will share how we have worked with Terra science teams and affiliated systems to see the potential stories in their data and the value of providing the data in a timely fashion. Terra has allowed us to tell the stories of our Earth today like never before.

Aerosols and water vapor dynamics over the Kingdom of Saudi Arabia

NASA Astrophysics Data System (ADS)

Farahat, Ashraf; El-Askary, Hesham; Al-Shaibani, Abdulaziz; Dogan, Umran

2014-05-01

The Kingdom of Saudi Arabia contains a vast desert area and the home of some of the largest deserts worldwide. This nature subjects the area to numerous dust storms. This is in addition to local emissions transported from industrial activities. The Arabian Peninsula dust storms have a major impact on air quality and affects dust cycle around the world. The nature of dust also affects air, ground traffics, and human health. Aerosols play a pivotal role in global climate change through their effects on the hydrological cycle and solar energy budget. Recently there have been some trials to study the nature of dust over the kingdom using satellite remote sensing and modeling to investigate the impact of aerosols of natural and anthropogenic origins from both local emissions and long-range transport on the air quality and atmospheric composition, yet a lot more needs to be done. In this study, data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board of Terra and Aqua satellites are used to analyze aerosols properties over the thirteen provinces of the Kingdom of Saudi Arabia from April 2003 to January 2012. This analysis will help to characterize aerosol and cloud properties, and the seasonal hydrological factors to establish the relative contributions of aerosols derived from different regions to the different Saudi provinces and their impacts on local atmospheric composition and air quality. During this period, we have examined possible nature and anthropogenic/natural aerosols/dust sources. The analysis is based on important parameters including the aerosol optical depth (AOD), fine mode fraction (FMF), cloud properties including cloud top temperature (CTT), cloud top pressure (CTP) and the water vapor column. Correlation between water vapor and AOD was observed over three provinces which could be a result of pollution aerosols rather than dust and is, hence, acting as cloud condensation nuclei (CCN). Increasing anomalous aerosols pattern

Assessing Terra Disposal Orbit Candidates from an Orbital Debris Perspective

NASA Technical Reports Server (NTRS)

Abraham, Andrew J.; Thompson, Roger C.; Mantziaras, Dimitrios C.

2016-01-01

The NASA Terra satellite is reaching the end of its mission life. Because the satellite resides in the 705 km Earth Science Constellation, disposal strategies need to be considered to remove it from this densely populated operational orbit. Of critical importance was the need to examine the future potential risk to other satellite residents of the 705 km constellation due to an unexpected breakup event of the Terra satellite post-disposal. This study quantifies the comparative risk of debris impacts associated with the two leading candidate disposal orbits (701 km vs. 686 km) and characterizes the suitability of each orbit for the purpose of long-term spacecraft disposal. The increase in collision risk to any member of the 705 km Earth Science Constellation is very modest. The long-term, average, total risk (including the ambient background risk) due to a Terra breakup at a disposal of -19 km (i.e., 686 km) relative to the 705 km constellation is 9.7 × 10(exp -6) impacts/day versus 1.0 × 10(exp -5) impacts/day for a disposal of only -4 km (i.e., 701 km). For perspective, note that the nominal space background risk to the 705 km constellation is 9.2 × 10(exp -6) impacts/day which implies a very modest increase in risk (approximately 3% difference between the two cases) due to a Terra breakup in either disposal orbit.

Urbanization: Riyadh, Saudi Arabia

NASA Image and Video Library

2001-10-22

Riyadh, the national capital of Saudi Arabia, is shown in 1972, 1990 and 2000. Its population grew in these years from about a half million to more than two million. Saudi Arabia experienced urbanization later than many other countries; in the early 1970s its urban-rural ratio was still about 1:3. By 1990 that had reversed to about 3:1. The city grew through in-migration from rural areas, and from decreases in the death rate while birthrates remained high. The 1972 image is a Landsat MSS scene; the 1990 image is a Landsat Thematic Mapper scene; and the 2000 image is an ASTER scene. All three images cover an area of about 27 x 34 km. The image is centered at 24.6 degrees north latitude, 46.6 degrees east longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11087

Diabetes Mellitus in Saudi Arabia: A Review of the Recent Literature.

PubMed

Al Dawish, Mohamed Abdulaziz; Robert, Asirvatham Alwin; Braham, Rim; Al Hayek, Ayman Abdallah; Al Saeed, Abdulghani; Ahmed, Rania Ahmed; Al Sabaan, Fahad Sulaiman

2016-01-01

The World Health Organization (WHO) has reported that Saudi Arabia ranks the second highest in the Middle East, and is seventh in the world for the rate of diabetes. It is estimated that around 7 million of the population are diabetic and almost around 3 million have pre-diabetes. Even more worrying perhaps, is the increasing pattern of diabetes noted in Saudi Arabia in the recent past. In fact, diabetes has approximately registered a ten-fold increase in the past three eras in Saudi Arabia. Diabetes mellitus (DM) has been found to be related to high mortality, morbidity and vascular complications, accompanied by poor general health and lower quality of life. In Saudi Arabia, DM is quickly reaching disturbing proportions and becoming a significant cause of medical complications and even death. However, when compared with the developed countries, the research work conducted, focusing particularly on the incidence, prevalence and socio-demographic properties of DM is woefully inadequate. The health burden due to DM in Saudi Arabia is predicted to rise to catastrophic levels, unless a wide-ranging epidemic control program is incorporated, with great emphasis laid on advocating a healthy diet, including exercise and active lifestyles, and weight control. To properly manage the DM in Saudi Arabia, a multidisciplinary approach is required. In this review we discuss all the aspects of DM in Saudi Arabia drawing from the published literature currently available.

Special Education in Saudi Arabia: Challenges, Perspectives, Future Possibilities

ERIC Educational Resources Information Center

Alquraini, Turki

2011-01-01

This paper provides a brief background of the education system in Saudi Arabia and current special education services and programs for students with disabilities. Additionally, this paper presents the findings of some studies that examined teachers' perspectives regarding the inclusion of students with disabilities. As Saudi Arabia continues its…

Special Education in Saudi Arabia: Challenges, Perspectives, Future Possibilities

ERIC Educational Resources Information Center

Alquraini, Turki

2010-01-01

This paper provides a brief background of the education system in Saudi Arabia and current special education services and programs for students with disabilities. Additionally, this paper presents the findings of some studies that examined teachers' perspectives regarding the inclusion of students with disabilities. As Saudi Arabia continues its…

Toxicity assessment in marine sediment for the Terra Nova environmental effects monitoring program (1997-2010)

NASA Astrophysics Data System (ADS)

Whiteway, Sandra A.; Paine, Michael D.; Wells, Trudy A.; DeBlois, Elisabeth M.; Kilgour, Bruce W.; Tracy, Ellen; Crowley, Roger D.; Williams, Urban P.; Janes, G. Gregory

2014-12-01

This paper discusses toxicity test results on sediments from the Terra Nova offshore oil development. The Terra Nova Field is located on the Grand Banks approximately 350 km southeast of Newfoundland (Canada). The amphipod (Rhepoxynius abronius) survival and solid phase luminescent bacteria (Vibrio fischeri, or Microtox) assays were conducted on sediment samples collected from approximately 50 stations per program year around Terra Nova during baseline (1997), prior to drilling, and in 2000, 2001, 2002, 2004, 2006, 2008 and 2010 after drilling began. The frequency of toxic responses in the amphipod toxicity test was low. Of the ten stations that were toxic in environmental effects monitoring (EEM) years, only one (station 30(FE)) was toxic in more than one year and could be directly attributed to Terra Nova project activities. In contrast, 65 (18%) of 364 EEM samples were toxic to Microtox. Microtox toxicity in EEM years was not related to distance from Terra Nova drill centres or concentrations of >C10-C21 hydrocarbons or barium, the primary constituents of the synthetic-based drill muds used at Terra Nova. Of the variables tested, fines and strontium levels showed the strongest (positive) correlations with toxicity. Neither fines nor strontium levels were affected by drill cuttings discharge at Terra Nova, except at station 30(FE) (and that station was not toxic to Microtox). Benthic macro-invertebrate abundance, richness and diversity were greater in toxic than in non-toxic sediments. Therefore, Microtox responses indicating toxicity were associated with positive biological responses in the field. This result may have been an indirect function of the increased abundance of most invertebrate taxa in less sandy sediments with higher gravel content, where fines and strontium levels and, consequently, toxicity to Microtox were high; or chemical substances released by biodegradation of organic matter, where invertebrates are abundant, may be toxic to Microtox. Given

NASA Terra Spacecraft Images Russian Volcanic Eruption

NASA Image and Video Library

2013-01-16

Plosky Tolbachik volcano in Russia far eastern Kamchatka peninsula erupted on Nov. 27, 2012, for the first time in 35 years, sending clouds of ash to the height of more than 9,800 feet 3,000 meters in this image from NASA Terra spacecraft.

Characteristics of Intracrater Thermal Anomalies in Southwestern Margaritifer Terra

NASA Astrophysics Data System (ADS)

McDowell, M. L.; Hamilton, V. E.

2005-03-01

We use thermophysical properties, albedo, short wavelength emissivity, composition, and geomorphology to understand the formation of anomalously warm intracrater deposits in southwestern Margaritifer Terra.

The Coupled Roles of Dust and Clouds in the Mars Climate

NASA Technical Reports Server (NTRS)

Clancy, R. Todd

2000-01-01

During the period October 1997 to September 1999 we obtained and analyzed over 100 millimeter-wave observations of Mars atmospheric CO line absorption for atmospheric temperature profiles. These measurements extend through one full Mars year (solar longitudes L(sub S) of 190 deg in 1997 to 180 deg in 1999) and coincide with atmospheric temperature profile and dust column measurements front the Thermal Emission Spectrometer (TES) experiment on board the Mars Global Surveyor (MGS) spacecraft. A comparison of Mars atmospheric temperatures retrieved by these distinct methods provides the first opportunity to place the long-term (1982-1999) millimeter retrievals of Mars atmospheric temperatures within the context of contemporaneous, spatially mapped spacecraft, observations. Profile comparisons of 0-30 km altitude atmospheric temperatures retrieved with the two techniques agree typically to within the 5 K calibration accuracy of the millimeter observations. At the 0.5 mbar pressure level (approximately 25 km altitude) the 30N/30S average for TES infrared temperatures and the disk-averaged millimeter temperatures are also well correlated in their seasonal and dust-storm-related variations over the 1997-1999 period. This period includes the Noachis Terra regional dust storm, which led to very abrupt heating (approximately 15 K at 0.5 mbar) of the global Mars atmosphere at L(sub S)=224 deg in 1997 [Christensen et al., 1998; Conrath et al., this issue; Smith et al., this issue]. Much colder (10-20 K) global atmospheric temperatures were observed during the 1997 versus 1977 perihelion periods (L(sub S)=200 deg-330 deg), consistent with the much (2 to 8 times) lower global dust loading of the atmosphere during the 1997 perihelion dust storm season versus the Viking period of the 1977a,b storms. The 1998-1999 Mars atmosphere revealed by both the millimeter and TES observations is also 10-15 K colder than presented by the Viking climatology during the aphelion season (L(sub S

Conservation in Saudi Arabia; moving from strategy to practice.

PubMed

Barichievy, Chris; Sheldon, Rob; Wacher, Tim; Llewellyn, Othman; Al-Mutairy, Mohammed; Alagaili, Abdulaziz

2018-02-01

Conservation in the Kingdom of Saudi Arabia is relatively young, yet have made considerable gains in conservation through strategic proclamation and reintroductions. Changes in land use, illegal hunting and competition with domestic stock has decimated the native ungulates, meaning that the survival of the native ungulate species is now completely dependent on protected area network. The challenge is to sustain this network to make meaningful conservation impact into the future. We review the status of ungulate conservation in Saudi Arabia and highlight that the conservation strategy is well developed. The major challenge faced in conservation in Saudi Arabia now is to implement what has been sanctioned.

Meet EPA Environmental Engineer Terra Haxton, Ph.D.

EPA Pesticide Factsheets

EPA Environmental Engineer Terra Haxton, Ph.D., uses computer simulation models to protect drinking water. She investigates approaches to help water utilities be better prepared to respond to contamination incidents in their distribution systems.

Multi Plumes and Their Flows beneath Arabia and East Africa

NASA Astrophysics Data System (ADS)

Chang, S.; van der Lee, S.

2010-12-01

The three-dimensional S-velocity structure beneath Arabia and East Africa is estimated down to the lower mantle to investigate vertical and horizontal extension of low-velocity anomalies that bear out the presence of mantle plumes and their flows beneath lithosphere. We estimated this model through joint inversion of teleseismic S- and SKS-arrival times, regional S- and Rayleigh waveform fits, fundamental-mode Rayleigh-wave group velocities, and independent Moho constraints from receiver functions, reflection/refraction profiles, and gravity measurements. With the unprecedented resolution in our S-velocity model, we found different flow patterns of hot materials upwelling beneath Afar beneath the Red Sea and the Gulf of Aden. While the low-velocity anomaly from Afar is well confined beneath the Gulf of Aden, inferring mantle flow along the gulf, N-S channel of low velocity is found beneath Arabia, not along the Red Sea. The Afar plume is distinctively separate from the Kenya plume, showing its origin in the lower mantle beneath southwestern Arabia. We identified another low-velocity extension to the lower mantle beneath Jordan and northern Arabia, which is thought to have caused volcanism in Jordan, northern Arabia, and possibly southern Turkey. Comparing locations of mantle plumes from the joint inversion with fast axes of shear-wave splitting, we confirmed horizontal plume flow from Afar in NS direction beneath Arabia and in NE-SW direction beneath Ethiopia as a likely cause of the observed seismic anisotropy.

Geologic map of the Lada Terra quadrangle (V-56), Venus

USGS Publications Warehouse

Kumar, P. Senthil; Head, James W.

2013-01-01

This publication provides a geological map of Lada Terra quadrangle (V–56), a portion of the southern hemisphere of Venus that extends from lat 50° S. to 70° S. and from long 0° E. to 60° E. V–56 is bordered by Kaiwan Fluctus (V–44) and Agnesi (V–45) quadrangles in the north and by Mylitta Fluctus (V–61), Fredegonde (V–57), and Hurston (V–62) quadrangles in the west, east, and south, respectively. The geological map of V–56 quadrangle reveals evidence for tectonic, volcanic, and impact processes in Lada Terra in the form of tesserae, regional extensional belts, coronae, and volcanic plains. In addition, the map also shows relative age relations such as overlapping or cross-cutting relations between the mapped geologic units. The geology observed within this quadrangle addresses (1) how coronae evolved in association with regional extensional belts and (2) how tesserae, regional plains, and impact craters, which are also significant geological units observed in Lada Terra quadrangle, were formed.

Research progress and prospects of Saudi Arabia in global medical sciences.

PubMed

Meo, S A; Hassan, A; Usmani, A M

2013-12-01

Since last decade, Saudi Arabia has been swiftly moving ahead to promote an education and research in the country. This study aimed to investigate the research outcome of Saudi Arabia in medical sciences during the period 1996-2012. In this study, the research papers published in various global science journals during the period 1996-2012 were accessed. We recorded the total number of research documents having an affiliation with Saudi Arabia. The main source for information was Institute of Scientific Information (ISI) Web of Science, Thomson Reuters and SCI-mago/Scopus. In global science data base, Saudi Arabia contributed 103804 documents in all science and social sciences. In medicine the total number of research papers from Saudi Arabia are 16196, citable documents 14732, total citations 102827, citations per documents 6.36 and Hirsch index (h-index) is 92. However, in combined medical and allied health sciences the total number of research papers are 27246, citable documents 25416, total citations 181999, mean citations per documents 7.07 and mean h-index is 41.44. Furthermore, Saudi Arabia contributed 40797 research documents in ISI indexed journals only and also 151 research documents in highly reputable and towering science journals. Saudi Arabia's research performance in global medical sciences has markedly increased during the period 2006-2012. The research publications are continuously on mounting path; however, the number of citations has decreased. The country improved its regional as well as international research rankings and graded 45 in the world in year 2012.

Eastern Ishtar Terra: Tectonic evolution derived from recognized features

NASA Technical Reports Server (NTRS)

Vorderbruegge, R. W.; Head, James W.

1989-01-01

Previous analyses have recognized several styles and orientations of compressional deformation, crustal convergence, and crustal thickening in Eastern Ishtar Terra. An east to west sense of crustal convergence through small scale folding, thrusting, and buckling is reflected in the high topography and ridge-and-valley morphology of Maxwell Montes and the adjacent portion of Fortuna Tessera. This east to west convergence was accompanied by up to 1000 km of lateral motion and large scale strike-slip faulting within two converging shear zones which has resulted in the present morphology of Maxwell Montes. A more northeast to southwest sense of convergence through large scale buckling and imbrication is reflected in large, northwest-trending scarps along the entire northern boundary of Ishtar Terra, with up to 2 km of relief present at many of the scarps. It was previously suggested that both styles of compression have occurred at the expense of pre-existing tessera regions which have then been overprinted by the latest convergence event. The difference in style is attributed mostly to differences in the properties of the crust converging with the tessera blocks. If one, presumably thick, tessera block converges with another tessera region, then the widespread, distributed style of deformation occurs, as observed in western Fortuna Tessera. However, if relatively thin crust (such as suggested for the North Polar Plains converges with thicker tessera regions, then localized deformation occurs, as reflected in the scarps along Northern Ishtar Terra. The purpose is to identify the types of features observed in Eastern Ishtar Terra. Their potential temporal and spatial relationships, is described, possible origins for them is suggested, and how the interpretation of some of these features has led to the multiple-style tectonic evolution model described is shown.

Discrimination of crop types with TerraSAR-X-derived information

NASA Astrophysics Data System (ADS)

Sonobe, Rei; Tani, Hiroshi; Wang, Xiufeng; Kobayashi, Nobuyuki; Shimamura, Hideki

Although classification maps are required for management and for the estimation of agricultural disaster compensation, those techniques have yet to be established. This paper describes the comparison of three different classification algorithms for mapping crops in Hokkaido, Japan, using TerraSAR-X (including TanDEM-X) dual-polarimetric data. In the study area, beans, beets, grasslands, maize, potatoes and winter wheat were cultivated. In this study, classification using TerraSAR-X-derived information was performed. Coherence values, polarimetric parameters and gamma nought values were also obtained and evaluated regarding their usefulness in crop classification. Accurate classification may be possible with currently existing supervised learning models. A comparison between the classification and regression tree (CART), support vector machine (SVM) and random forests (RF) algorithms was performed. Even though J-M distances were lower than 1.0 on all TerraSAR-X acquisition days, good results were achieved (e.g., separability between winter wheat and grass) due to the characteristics of the machine learning algorithm. It was found that SVM performed best, achieving an overall accuracy of 95.0% based on the polarimetric parameters and gamma nought values for HH and VV polarizations. The misclassified fields were less than 100 a in area and 79.5-96.3% were less than 200 a with the exception of grassland. When some feature such as a road or windbreak forest is present in the TerraSAR-X data, the ratio of its extent to that of the field is relatively higher for the smaller fields, which leads to misclassifications.

Surface properties of ancient cratered terrain in the northern hemisphere of Mars

NASA Technical Reports Server (NTRS)

Zimbelman, J. R.; Greeley, R.

1982-01-01

Viking high resolution IR data is used in an examination of the hilly and cratered material of Scott and Carr (1978), supposed to be the oldest extensively exposed surface on Mars. Measured nighttime temperatures at 11 and 20 microns indicate inertia blocks, surrounded by lower thermal inertia soil. Geologic features crossed by the Viking data generally show no difference from the regional properties. Imaging data from within and around the Arabia low thermal inertia region indicate that subdued surface morphology is not always associated with low thermal inertias. The mantling of ancient northern hemisphere cratered terrain by fine grained material does not allow thermal measurements to be directly related to rock unit properties, but less mantling may be present in southern hemisphere locations of this material.

Women and Education in Saudi Arabia: Challenges and Achievements

ERIC Educational Resources Information Center

Hamdan, Amani

2005-01-01

The historical socio-economic and political conditions of Saudi Arabia are an essential aspect of understanding a woman's position in Saudi society. The persistence of women's exclusion from public life in contemporary Saudi Arabia is one of the most heated debates not only among Muslims but also worldwide, as Saudi society comes under more and…

TerraSAR-X InSAR multipass analysis on Venice, Italy)

NASA Astrophysics Data System (ADS)

Nitti, D. O.; Nutricato, R.; Bovenga, F.; Refice, A.; Chiaradia, M. T.; Guerriero, L.

2009-09-01

The TerraSAR-X (copyright) mission, launched in 2007, carries a new X-band Synthetic Aperture Radar (SAR) sensor optimally suited for SAR interferometry (InSAR), thus allowing very promising application of InSAR techniques for the risk assessment on areas with hydrogeological instability and especially for multi-temporal analysis, such as Persistent Scatterer Interferometry (PSI) techniques, originally developed at Politecnico di Milano. The SPINUA (Stable Point INterferometry over Unurbanised Areas) technique is a PSI processing methodology which has originally been developed with the aim of detection and monitoring of coherent PS targets in non or scarcely-urbanized areas. The main goal of the present work is to describe successful applications of the SPINUA PSI technique in processing X-band data. Venice has been selected as test site since it is in favorable settings for PSI investigations (urban area containing many potential coherent targets such as buildings) and in view of the availability of a long temporal series of TerraSAR-X stripmap acquisitions (27 scenes in all). The Venice Lagoon is affected by land sinking phenomena, whose origins are both natural and man-induced. The subsidence of Venice has been intensively studied for decades by determining land displacements through traditional monitoring techniques (leveling and GPS) and, recently, by processing stacks of ERS/ENVISAT SAR data. The present work is focused on an independent assessment of application of PSI techniques to TerraSAR-X stripmap data for monitoring the stability of the Venice area. Thanks to its orbital repeat cycle of only 11 days, less than a third of ERS/ENVISAT C-band missions, the maximum displacement rate that can be unambiguously detected along the Line-of-Sight (LOS) with TerraSAR-X SAR data through PSI techniques is expected to be about twice the corresponding value of ESA C-band missions, being directly proportional to the sensor wavelength and inversely proportional to the

MarCOs, Mars and Earth

NASA Image and Video Library

2018-03-29

An artist's rendering of the twin Mars Cube One (MarCO) spacecraft flying over Mars with Earth in the distance. The MarCOs will be the first CubeSats -- a kind of modular, mini-satellite -- flown in deep space. They're designed to fly along behind NASA's InSight lander on its cruise to Mars. If they make the journey, they will test a relay of data about InSight's entry, descent and landing back to Earth. Though InSight's mission will not depend on the success of the MarCOs, they will be a test of how CubeSats can be used in deep space. https://photojournal.jpl.nasa.gov/catalog/PIA22316

Mantle flow beneath Arabia offset from the opening Red Sea

NASA Astrophysics Data System (ADS)

Chang, Sung-Joon; Merino, Miguel; Van der Lee, Suzan; Stein, Seth; Stein, Carol A.

2011-02-01

Continental rifting involves a poorly understood sequence of lithospheric stretching, volcanism, and mantle flow that evolves to seafloor spreading. We present new insight from inversion of seismic traveltimes and waveforms beneath Arabia and surroundings. Low velocities occur beneath the southern Red Sea and Gulf of Aden, consistent with active spreading. However, hot material extends not below the northern Red Sea, but is offset eastward beneath Arabia, showing mantle flow from the Afar hotspot. The location of this channel beneath volcanic rocks erupted since rifting began 30 million years ago indicates that flow moves with Arabia. We propose that the absence of seafloor spreading in the northern Red Sea reflects the offset flow. This geometry may evolve to spreading in the Northern Red Sea, rifting of Arabia, or both. This situation has aspects of both active and passive rifting, showing that both can occur before coalescing to seafloor spreading.

Individualized medicine enabled by genomics in Saudi Arabia

PubMed Central

2015-01-01

The biomedical research sector in Saudi Arabia has recently received special attention from the government, which is currently supporting research aimed at improving the understanding and treatment of common diseases afflicting Saudi Arabian society. To build capacity for research and training, a number of centres of excellence were established in different areas of the country. Among these, is the Centre of Excellence in Genomic Medicine Research (CEGMR) at King Abdulaziz University, Jeddah, with its internationally ranked and highly productive team performing translational research in the area of individualized medicine. Here, we present a panorama of the recent trends in different areas of biomedical research in Saudi Arabia drawing from our vision of where genomics will have maximal impact in the Kingdom of Saudi Arabia. We describe advances in a number of research areas including; congenital malformations, infertility, consanguinity and pre-implantation genetic diagnosis, cancer and genomic classifications in Saudi Arabia, epigenetic explanations of idiopathic disease, and pharmacogenomics and personalized medicine. We conclude that CEGMR will continue to play a pivotal role in advances in the field of genomics and research in this area is facing a number of challenges including generating high quality control data from Saudi population and policies for using these data need to comply with the international set up. PMID:25951871

Saudi Arabia.

PubMed

1986-12-01

In 1985, Saudi Arabia's population stood at 9.6 million, with an annual growth rate of 2.8%. The infant mortality rate was 78/1000 and life expectancy was 60 years. Literacy was at the 50% level among men and 25% among women. Of the work force of 3 million, 66% are foreign workers. The labor force is distributed as follows: agriculture, 14%; industry, 11%; services, commerce, and government, 53%; construction, 20%; and oil and mining, 2%. The GDP was US$98.1 billion in 1985-86, with an annual growth rate of 8% and a per capita GDP of $9800. Under the impact of rapid economic growth, urbanization has advanced rapidly and 95% of the population is now settled. Saudi Arabia, a monarchy, is divided into 14 provinces that are governed by princes or relatives of the royal family. Oil is the major source of foreign exchange, contributing 81% of government revenues. Ample government funds and foreign exchange resources are available for development, defense, and aid to other Arab and Islamic countries. The government has sought to allocate its petroleum income to transform its relatively undeveloped oil-based economy into that of a modern industrial state while maintaining traditional Islamic values. The standard of living of most Saudis has improved significantly. A shortage of skilled workers at all levels remains the principal obstacle to rapid development.

Terra Nova Bay Polynya, Antarctica

NASA Technical Reports Server (NTRS)

2007-01-01

In Terra Nova Bay, off the Scott Coast of Victoria Land, Antarctica, a large pocket of open water persists throughout most of the Southern Hemisphere winter, even while most of the rest of the Antarctic coastline is firmly embraced by the frozen Southern Ocean. This pocket of open water--a polynya--results from exceptionally strong winds that blow downslope from the Trans-Antarctic Mountains. These fierce katabatic winds drive the sea ice eastward. Since the dominant ice drift pattern in the area is northward, the Drygalski Ice Tongue prevents the bay from being re-populated with sea ice. This image of the Terra Nova Bay polynya was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on October 16, 2007. Sea ice sits over the Ross Sea like a cracked and crumbling windshield. Blue-tinged glaciers flow down from the Trans-Antarctic Mountains. Although glaciers can appear blue because of melt water, they can also get that tint when the wind scours and polishes the ice surface. Given the strength of the katabatic winds along this part of the Antarctic coast, it is likely that the blue color of these glaciers is a result of their having been swept clean of snow. The large image has a spatial resolution (level of detail) of 250 meters per pixel.

Mars

NASA Technical Reports Server (NTRS)

Kieffer, Hugh H. (Editor); Jakosky, Bruce M. (Editor); Snyder, Conway W. (Editor); Matthews, Mildred S. (Editor)

1992-01-01

The present volume on Mars discusses visual, photographic and polarimetric telescopic observations, spacecraft exploration of Mars, the origin and thermal evolution of Mars, and the bulk composition, mineralogy, and internal structure of the planet. Attention is given to Martian gravity and topography, stress and tectonics on Mars, long-term orbital and spin dynamics of Mars, and Martian geodesy and cartography. Topics addressed include the physical volcanology of Mars, the canyon system on planet, Martian channels and valley networks, and ice in the Martian regolith. Also discussed are Martian aeolian processes, sediments, and features, polar deposits of Mars, dynamics of the Martian atmosphere, and the seasonal behavior of water on Mars.

Mantle plumes and associated flow beneath Arabia and East Africa

NASA Astrophysics Data System (ADS)

Chang, Sung-Joon; Van der Lee, Suzan

2011-02-01

We investigate mantle plumes and associated flow beneath the lithosphere by imaging the three-dimensional S-velocity structure beneath Arabia and East Africa. This image shows elongated vertical and horizontal low-velocity anomalies down to at least mid mantle depths. This three-dimensional S-velocity model is obtained through the joint inversion of teleseismic S- and SKS-arrival times, regional S- and Rayleigh waveform fits, fundamental-mode Rayleigh-wave group velocities, and independent Moho constraints from receiver functions, reflection/refraction profiles, and gravity measurements. In the resolved parts of our S-velocity model we find that the Afar plume is distinctly separate from the Kenya plume, showing the Afar plume's origin in the lower mantle beneath southwestern Arabia. We identify another quasi-vertical low-velocity anomaly beneath Jordan and northern Arabia which extends into the lower mantle and may be related to volcanism in Jordan, northern Arabia, and possibly southern Turkey. Comparing locations of mantle plumes from the joint inversion with fast axes of shear-wave splitting, we confirm horizontal mantle flow radially away from Afar. Low-velocity channels in our model support southwestward flow beneath Ethiopia, eastward flow beneath the Gulf of Aden, but not northwestwards beneath the entire Red Sea. Instead, northward mantle flow from Afar appears to be channeled beneath Arabia.

Mars Express Seen by Mars Global Surveyor

NASA Image and Video Library

2005-05-19

This picture of the European Space Agency Mars Express spacecraft by the Mars Orbiter Camera on NASA Mars Global Surveyor is from the first successful imaging of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars.

TERRA: a computer code for simulating the transport of environmentally released radionuclides through agriculture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baes, C.F. III; Sharp, R.D.; Sjoreen, A.L.

1984-11-01

TERRA is a computer code which calculates concentrations of radionuclides and ingrowing daughters in surface and root-zone soil, produce and feed, beef, and milk from a given deposition rate at any location in the conterminous United States. The code is fully integrated with seven other computer codes which together comprise a Computerized Radiological Risk Investigation System, CRRIS. Output from either the long range (> 100 km) atmospheric dispersion code RETADD-II or the short range (<80 km) atmospheric dispersion code ANEMOS, in the form of radionuclide air concentrations and ground deposition rates by downwind location, serves as input to TERRA. User-definedmore » deposition rates and air concentrations may also be provided as input to TERRA through use of the PRIMUS computer code. The environmental concentrations of radionuclides predicted by TERRA serve as input to the ANDROS computer code which calculates population and individual intakes, exposures, doses, and risks. TERRA incorporates models to calculate uptake from soil and atmospheric deposition on four groups of produce for human consumption and four groups of livestock feeds. During the environmental transport simulation, intermediate calculations of interception fraction for leafy vegetables, produce directly exposed to atmospherically depositing material, pasture, hay, and silage are made based on location-specific estimates of standing crop biomass. Pasture productivity is estimated by a model which considers the number and types of cattle and sheep, pasture area, and annual production of other forages (hay and silage) at a given location. Calculations are made of the fraction of grain imported from outside the assessment area. TERRA output includes the above calculations and estimated radionuclide concentrations in plant produce, milk, and a beef composite by location.« less

Two MODIS Aerosol Products Over Ocean on the Terra and Aqua CERES SSF Datasets

NASA Technical Reports Server (NTRS)

Ignatov, Alexander; Minnis, Patrick; Loeb, Norman; Wielicki, Bruce; Miller, Walter; Sun-Mack, Sunny; Tanre, Didier; Remer, Lorraine; Laszlo, Istvan; Geier, Erika

2004-01-01

Over ocean, two aerosol products are reported on the Terra and Aqua CERES SSFs. Both are derived from MODIS, but using different sampling and aerosol algorithms. This study briefly summarizes these products, and compares using 2 weeks of global Terra data from 15-21 December 2000, and 1-7 June 2001.

Structural Analysis of Ogygis Rupes Lobate Scarp on Mars.

NASA Astrophysics Data System (ADS)

Herrero-Gil, A.; Ruiz, J.; Romeo, I.; Egea-González, I.

2016-12-01

Ogygis Rupes is a 200 kilometers long lobate scarp, striking N30ºE, with approximately 2km of maximum structural relief. It is located in Aonia Terra, in the southern hemisphere of Mars near the northeast margin of Argyre impact basin. Similar to other large lobate scarps on Mercury or Mars, it shows a roughly arcuate to linear form, and an asymmetric cross section with a steeply rising scarp face and a gently declining back scarp. This asymmetry suggests that Ogygis Rupes is the topographic expression of a ESE-vergent thrust fault. By using the Mars Orbiter Laser Altimeter data and the Mars imagery available we have measure the horizontal shortening on impact craters cross-cut by this lobate scarp to obtain a minimum value for the horizontal offset of the underling fault. Two complementary methods were used to estimate fault geometry parameters as fault displacement, dip angle and depth of faulting: (i) analyzing topographic profiles together with the horizontal shortening estimations from cross-cut craters to create balanced cross sections on the basis of the thrust fault propagation folding [1]; (ii) using a forward mechanical dislocation method [2], which predicts fault geometry by comparing model outputs with real topography. The significant size of the fault underlying this lobate scarp suggests that its detachment is located at a main rheological change, for which we have obtained a preliminary depth value of around 30 kilometers by the methods listed above. Estimates of the depth of faulting in similar lobate scarps [3] have been associated to the depth of the brittle-ductile transition. [1] Suppe (1983), Am. J. Sci., 283, 648-721; Seeber and Sorlien (2000), Geol. Soc. Am. Bull., 112, 1067-1079. [2] Toda et al. (1998) JGR, 103, 24543-24565. [3] i.e. Schultz and Watters (2001) Geophys. Res. Lett., 28, 4659-4662; Ruiz et al. (2008) EPSL, 270, 1-12; Egea-Gonzalez et al. (2012) PSS, 60, 193-198; Mueller et al. (2014) EPSL, 408, 100-109.

Geological Evidence for Recent Ice Ages on Mars

NASA Astrophysics Data System (ADS)

Head, J. W.; Mustard, J. F.; Kreslavsky, M. A.; Milliken, R. E.; Marchant, D. R.

2003-12-01

A primary cause of ice ages on Earth is orbital forcing from variations in orbital parameters of the planet. On Mars such variations are known to be much more extreme. Recent exploration of Mars has revealed abundant water ice in the near-surface at high latitudes in both hemispheres. We outline evidence that these near-surface, water-ice rich mantling deposits represent a mixture of ice and dust that is layered, meters thick, and latitude dependent. These units were formed during a geologically recent major martian ice age, and were emplaced in response to the changing stability of water ice and dust on the surface during variations in orbital parameters. Evidence for these units include a smoothing of topography at subkilometer baselines from about 30o north and south latitudes to the poles, a distinctive dissected texture in MOC images in the +/-30o-60o latitude band, latitude-dependent sets of topographic characteristics and morphologic features (e.g., polygons, 'basketball' terrain texture, gullies, viscous flow features), and hydrogen concentrations consistent with the presence of abundant ice at shallow depths above 60o latitude. The most equatorward extent of these ice-rich deposits was emplaced down to latitudes equivalent to Saudi Arabia and the southern United States on Earth during the last major martian ice age, probably about 0.4-2.1 million years ago. Mars is currently in an inter-ice age period and the ice-rich deposits are presently undergoing reworking, degradation and retreat in response to the current stability relations of near-surface ice. Unlike Earth, martian ice ages are characterized by warmer climates in the polar regions and the enhanced role of atmospheric water ice and dust transport and deposition to produce widespread and relatively evenly distributed smooth deposits at mid-latitudes during obliquity maxima.

75 FR 21598 - Energy and Infrastructure Mission to Saudi Arabia

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

.... Participating in an official U.S. industry delegation, rather than traveling to Saudi Arabia independently, will... petrochemical industry. Construction At a time when some Middle Eastern countries are facing financial.... Likewise, the Saudi real estate market is set to grow significantly over the next four years. Saudi Arabia...

National Culture-Management Practices: United States and Saudi Arabia Contrasted.

ERIC Educational Resources Information Center

Hashmi, Mahmud S.

Successful conduct of business in Saudi Arabia requires attitudes and skills significantly different from those needed in the United States. Distinct societal differences can turn winning practices in one culture into failures in another. Despite Saudi Arabia's recent emergence as a wealthy marketplace, traditional values and a unique lifestyle…

Searching for Aqueous Activity on Mars through Analyses of OMEGA Spectra

NASA Astrophysics Data System (ADS)

Bishop, J. L.; Bibring, J.-P.; Dyar, M. D.; Gendrin, A.; Lane, M. D.; Mustard, J. F.; Parente, M.; Poulet, F.

2005-08-01

Analyses of OMEGA spectra have shown the presence of sulfate and clay minerals in a number of regions including Valles Marineris, Nili Fossae and Terra Meridiani (1-4). We are searching for spectral features associated with these minerals in OMEGA image cubes and are using expanded spectral libraries to further characterize these features. Shown below are three OMEGA spectra from the Valles Marineris and Syrtis Major regions, identified from top to bottom as containing kieserite, nontronite, and polyhydrated sulfates (2,3). They are compared in the figure with spectra of nontronite and of the hydrous sulfate minerals szomolnokite (Fe2+SO4H2O kieserite group) and rozenite (Fe2+S44H2O starkeyite group). We seek to identify and characterize areas on Mars where it is possible to refine the mineralogical interpretations. We are searching for locations where minerals such as szomolnokite or rozenite may be the spectrally dominant component in spectra characterized so far as monohydrated and polyhydrated sulfates. 1) J.-P. Bibring et al., Science 307, 1576 (2005). 2) A. Gendrin et al., 2nd Conf. on Early Mars, Jackson Hole, Wyoming 2004. 3) A. Gendrin et al., Science 307, 1587 (2005). 4) J. F. Mustard et al., LPSC #1341 (2005).

EPA SITE DEMONSTRATION OF THE TERRA VAC IN SITU VACUUM EXTRACTION PROCESS IN GROVELAND, MASSACHUSETTS

EPA Science Inventory

This paper presents an EPA evaluation of the patented Terra Vac, Inc.'s in situ vacuum extraction process that was field-demonstrated on a trichloroethylene (TCE) contaminated soil in Groveland, MA, under the EPA Superfund Innovative Technology Evaluation (SITE) program. he Terra...

Tectonics and volcanism of Eastern Aphrodite Terra, Venus - No subduction, no spreading

NASA Technical Reports Server (NTRS)

Hansen, Vicki L.; Phillips, Roger J.

1993-01-01

Eastern Aphrodite Terra, a deformed region with high topographic relief on Venus, has been interpreted as analogous to a terrestrial extensional or convergent plate boundary. However, analysis of geological and structural relations indicates that the tectonics of eastern Aphrodite Terra is dominated by blistering of the crust by magma diapirs. The findings imply that, within this region, vertical tectonism dominates over horizontal tectonism and, consequently, that this region is neither a divergent nor a convergent plate boundary.

Genetic Stratigraphy of Key Demographic Events in Arabia

PubMed Central

Fernandes, Verónica; Triska, Petr; Pereira, Joana B.; Alshamali, Farida; Rito, Teresa; Machado, Alison; Fajkošová, Zuzana; Cavadas, Bruno; Černý, Viktor; Soares, Pedro

2015-01-01

At the crossroads between Africa and Eurasia, Arabia is necessarily a melting pot, its peoples enriched by successive gene flow over the generations. Estimating the timing and impact of these multiple migrations are important steps in reconstructing the key demographic events in the human history. However, current methods based on genome-wide information identify admixture events inefficiently, tending to estimate only the more recent ages, as here in the case of admixture events across the Red Sea (∼8–37 generations for African input into Arabia, and 30–90 generations for “back-to-Africa” migrations). An mtDNA-based founder analysis, corroborated by detailed analysis of the whole-mtDNA genome, affords an alternative means by which to identify, date and quantify multiple migration events at greater time depths, across the full range of modern human history, albeit for the maternal line of descent only. In Arabia, this approach enables us to infer several major pulses of dispersal between the Near East and Arabia, most likely via the Gulf corridor. Although some relict lineages survive in Arabia from the time of the out-of-Africa dispersal, 60 ka, the major episodes in the peopling of the Peninsula took place from north to south in the Late Glacial and, to a lesser extent, the immediate post-glacial/Neolithic. Exchanges across the Red Sea were mainly due to the Arab slave trade and maritime dominance (from ∼2.5 ka to very recent times), but had already begun by the early Holocene, fuelled by the establishment of maritime networks since ∼8 ka. The main “back-to-Africa” migrations, again undetected by genome-wide dating analyses, occurred in the Late Glacial period for introductions into eastern Africa, whilst the Neolithic was more significant for migrations towards North Africa. PMID:25738654

Genetic stratigraphy of key demographic events in Arabia.

PubMed

Fernandes, Verónica; Triska, Petr; Pereira, Joana B; Alshamali, Farida; Rito, Teresa; Machado, Alison; Fajkošová, Zuzana; Cavadas, Bruno; Černý, Viktor; Soares, Pedro; Richards, Martin B; Pereira, Luísa

2015-01-01

At the crossroads between Africa and Eurasia, Arabia is necessarily a melting pot, its peoples enriched by successive gene flow over the generations. Estimating the timing and impact of these multiple migrations are important steps in reconstructing the key demographic events in the human history. However, current methods based on genome-wide information identify admixture events inefficiently, tending to estimate only the more recent ages, as here in the case of admixture events across the Red Sea (~8-37 generations for African input into Arabia, and 30-90 generations for "back-to-Africa" migrations). An mtDNA-based founder analysis, corroborated by detailed analysis of the whole-mtDNA genome, affords an alternative means by which to identify, date and quantify multiple migration events at greater time depths, across the full range of modern human history, albeit for the maternal line of descent only. In Arabia, this approach enables us to infer several major pulses of dispersal between the Near East and Arabia, most likely via the Gulf corridor. Although some relict lineages survive in Arabia from the time of the out-of-Africa dispersal, 60 ka, the major episodes in the peopling of the Peninsula took place from north to south in the Late Glacial and, to a lesser extent, the immediate post-glacial/Neolithic. Exchanges across the Red Sea were mainly due to the Arab slave trade and maritime dominance (from ~2.5 ka to very recent times), but had already begun by the early Holocene, fuelled by the establishment of maritime networks since ~8 ka. The main "back-to-Africa" migrations, again undetected by genome-wide dating analyses, occurred in the Late Glacial period for introductions into eastern Africa, whilst the Neolithic was more significant for migrations towards North Africa.

CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM1_Edition1)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM2_Edition2)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

TerraFERMA: The Transparent Finite Element Rapid Model Assembler for multiphysics problems in Earth sciences

NASA Astrophysics Data System (ADS)

Wilson, Cian R.; Spiegelman, Marc; van Keken, Peter E.

2017-02-01

We introduce and describe a new software infrastructure TerraFERMA, the Transparent Finite Element Rapid Model Assembler, for the rapid and reproducible description and solution of coupled multiphysics problems. The design of TerraFERMA is driven by two computational needs in Earth sciences. The first is the need for increased flexibility in both problem description and solution strategies for coupled problems where small changes in model assumptions can lead to dramatic changes in physical behavior. The second is the need for software and models that are more transparent so that results can be verified, reproduced, and modified in a manner such that the best ideas in computation and Earth science can be more easily shared and reused. TerraFERMA leverages three advanced open-source libraries for scientific computation that provide high-level problem description (FEniCS), composable solvers for coupled multiphysics problems (PETSc), and an options handling system (SPuD) that allows the hierarchical management of all model options. TerraFERMA integrates these libraries into an interface that organizes the scientific and computational choices required in a model into a single options file from which a custom compiled application is generated and run. Because all models share the same infrastructure, models become more reusable and reproducible, while still permitting the individual researcher considerable latitude in model construction. TerraFERMA solves partial differential equations using the finite element method. It is particularly well suited for nonlinear problems with complex coupling between components. TerraFERMA is open-source and available at http://terraferma.github.io, which includes links to documentation and example input files.

Tectonic Evolution of Ishtar Terra: Processes of Crustal Shortening and Thickening on Venus.

NASA Astrophysics Data System (ADS)

Vorder Bruegge, Richard Walsh

Evidence for the horizontal movement of large areas of crust, mountain building, and the possible removal of crust through processes similar to those observed on Earth is found in the Ishtar Terra highland region of Venus. Ishtar Terra is 5000 x 1500 km in size, an area comparable to Australia. It is characterized by a 2-5 km high, flat plain, Lakshmi Planum, which is flanked by mountain belts that reach elevations of up to 11 km. Outboard of these mountain belts are complexly deformed 'tessera' regions at elevations of 1 to 6 km. Evidence for the creation of crust through a mechanism comparable to terrestrial seafloor spreading is found in the elevated Trough and Ridge Terrain of Eastern Fortuna Tessera. In addition, the region around the Trough and Ridge Terrain is characterized by an elevated and deformed surface which exhibits a morphology compatible with an origin through crustal shortening through the collision of thick blocks of crust, such as through continental or oceanic plateau collision on Earth. Folds, thrusts, and strike-slip faults, all indicative of crustal shortening, are identified in these regions, and indicate a variety of convergence directions. The collision of very thick crustal blocks also produces high orogenic belts through processes comparable to terrestrial orogenesis. However, some fundamental differences may also exist in orogenesis on the two planets. These differences are primarily related to the driving mechanisms and thermal effects of orogenesis. The surficial geological characteristics of the northern edge of Ishtar Terra have been combined with geophysical modelling and provide evidence that this region is characterized by the wholescale underthrusting of low-lying plains crust beneath the thicker crust of Ishtar Terra. This underthrusting process adds upper crustal material to Ishtar Terra through a suturing process analogous to that of sedimentary accretionary wedges on Earth. The primary conclusion of this work is that

Dust Devils Seen Streaking Across Mars: PART II--They're the Work of the Devil!

NASA Technical Reports Server (NTRS)

2000-01-01

[figure removed for brevity, see original site]

[figure removed for brevity, see original site]

In December 1999, the MOC team finally had an answer! A dust devil, shown in the above left figure, was caught in the act of creating a swirly, dark streak! An eerie sensation washed over the first team members who saw this picture--here was an event on Mars 'caught in the act' just hours before the picture was played back to Earth. A 'smoking gun.'

The first dust devil seen making a streak--located in Promethei Terra (above, left)--was traveling from right (east) to left (west). A columnar shadow was cast by sunlight coming from the upper left. This shadow indicates the true shape of the dust devil. The bright dust devil itself does not look like a column because the picture was taken from a camera looking straight down on it. The dust devil is less than 100 meters (less than 100 yards) wide and the picture covers an area approximately 1.5 by 1.7 kilometers (about 1 by 1 mile).

Dust devils are spinning, columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes. Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars. They form when the ground heats up during the day, warming the air immediately above the surface. As the warmed air nearest the surface begins to rise, it spins. The spinning column begins to move across the surface and picks up loose dust (if any is present). The dust makes the vortex visible and gives it the 'dust devil' or tornado-like appearance. On Earth, dust devils typically last for only a few minutes.

The fourth picture (above, right) shows a surface in southwestern Terra Sirenum near 63oS, 168oW, that has seen the activity of so many dust devils that it looks like a plate of dark gray spaghetti. This image, taken in early summer during February 2000, covers an area 3 km wide and 30 km long (1.9 by 19 miles). In fact, a dust devil

Geologic Mapping in Southern Margaritifer Terra

NASA Technical Reports Server (NTRS)

Irwin, R. P., III; Grant, J. A.

2010-01-01

Margaritifer Terra records a complex geologic history [1-5], and the area from Holden crater through Ladon Valles, Ladon basin, and up to Morava Valles is no exception [e.g., 6-13]. The 1:500,000 geologic map of MTM quadrangles -15027, -20027, -25027, and -25032 (Figs. 1 and 2 [14]) identifies a range of units that delineate the history of water-related activity and regional geologic context.

Adjustments to the MODIS Terra Radiometric Calibration and Polarization Sensitivity in the 2010 Reprocessing

NASA Technical Reports Server (NTRS)

Meister, Gerhard; Franz, Bryan A.

2011-01-01

The Moderate-Resolution Imaging Spectroradiometer (MODIS) on NASA s Earth Observing System (EOS) satellite Terra provides global coverage of top-of-atmosphere (TOA) radiances that have been successfully used for terrestrial and atmospheric research. The MODIS Terra ocean color products, however, have been compromised by an inadequate radiometric calibration at the short wavelengths. The Ocean Biology Processing Group (OBPG) at NASA has derived radiometric corrections using ocean color products from the SeaWiFS sensor as truth fields. In the R2010.0 reprocessing, these corrections have been applied to the whole mission life span of 10 years. This paper presents the corrections to the radiometric gains and to the instrument polarization sensitivity, demonstrates the improvement to the Terra ocean color products, and discusses issues that need further investigation. Although the global averages of MODIS Terra ocean color products are now in excellent agreement with those of SeaWiFS and MODIS Aqua, and image quality has been significantly improved, the large corrections applied to the radiometric calibration and polarization sensitivity require additional caution when using the data.

Essays on oil and business cycles in Saudi Arabia

NASA Astrophysics Data System (ADS)

Aba Alkhail, Bandar A.

This dissertation consists of three chapters. Chapter one presents a theoretical model using a dynamic stochastic general equilibrium (DSGE) approach to investigate the role of world oil prices in explaining the business cycle in Saudi Arabia. This model incorporates both productivity and oil revenue shocks. The results indicate that productivity shocks are relatively more important to business cycles than oil shocks. However, this model has some unfavorable features that are associated with both investment and labor hours. The second chapter presents a modified theoretical model using DSGE approach to examine the role of world oil prices versus productivity shocks in explaining the business cycles in Saudi Arabia. To overcome the unfavorable features of the baseline model, the alternative model adds friction to the model by incorporating investment portfolio adjustment cost. Thus, the alternative model produces similar dynamics to that of the baseline model but the unfavorable characteristics are eliminated. Also, this chapter conducts sensitivity analysis. The objective of the third chapter is to empirically investigate how real world oil price and productivity shocks affect output, consumption, investment, labor hours, and trade balance/output ratio for Saudi Arabia. This chapter complements the theoretical model of the previous chapters. In addition, this study builds a foundation for future studies in examining the impact of real world oil price shocks on the economies of key trade partners of Saudi Arabia. The results of the third chapter show that productivity shocks matter more for macroeconomic fluctuations than oil shocks for the Saudis' primary trade partners. Therefore, fears of oil importing countries appear to be overstated. As a whole, this research is important for the following reasons. First, the empirical model is consistent with the predictions of our theoretical model in that productivity is a driving force of business cycles in Saudi Arabia

SITE TECHNOLOGY CAPSULE: TERRA-KLEEN SOLVENT EXTRACTION TECHNOLOGY

EPA Science Inventory

Remediation of PCBs in soils has been difficult to implement on a full-scale, cost-effective basis. The Terra-Kleen solvent extraction system has overcome many of the soil handling, contaminant removal, and regulatory restrictions that have made it difficult to implement a cost-e...

Mars Express recent findings and future plans

NASA Astrophysics Data System (ADS)

Titov, Dmitrij; Bibring, Jean-Pierre; Cardesin, Alejandro; Duxbury, Thomas; Forget, Francois; Giuranna, Marco; González-Galindo, Francisco; Holmström, Mats; Jaumann, Ralf; Määttänen, Anni; Martin, Patrick; Montmessin, Franck; Orosei, Roberto; Pätzold, Martin; Plaut, Jeffrey; MEx SGS Team

2017-04-01

Mars Express remains one of ESA's most scientifically productive missions whose publication record now exceeds 1000 papers. Characterization of geological processes on a local-to-regional scale by HRSC, OMEGA and partner experiments on NASA spacecraft has allowed constraining land-forming processes in space and time. Recent results suggest episodic geological activity as well as the presence of large bodies of liquid water in several provinces (e.g. Eridania Planum, Terra Chimeria) in the early and middle Amazonian epoch and formation of vast sedimentary plains north of the Hellas basin. Mars Express observations and experimental teams provided an essential contribution to the selection of the Mars-2020 landing sites. More than a decade-long record of atmospheric parameters such as temperature, dust loading, water vapor and ozone abundance, water ice and CO2 clouds distribution, collected by SPICAM, PFS and OMEGA spectrometers as well as subsequent modeling have provided key contributions to our understanding of the martian climate. The ASPERA-3 observations of ion escape covering a complete solar cycle have revealed important dependencies of the atmospheric erosion rate on parameters of the solar wind and EUV flux. Structure of the ionosphere sounded by the MARSIS radar and the MaRS radio science experiment was found to be significantly affected by the solar activity, the crustal magnetic field, as well as by the influx of meteorite and cometary dust. MARSIS and ASPERA-3 observations suggest that the sunlit ionosphere over the regions with strong crustal fields is denser and extends to higher altitudes as compared to the regions with no crustal anomalies. The ionospheric plasma expands to higher altitudes where it contacts with the solar wind plasma. Reconnection of solar magnetic field lines carried by the solar wind with field lines of crustal origin opens channels through which the ionospheric plasma escapes to space, producing strong and narrow cavities in the

Investigating Mars: Russell Crater - False Color

NASA Image and Video Library

2017-08-11

This image shows the western part of the dune field on the floor of Russell Crater. This is a false color image of Russell crater and it's surroundings. Sand Dunes usually appear "blue" in false color images. Russell Crater is located in Noachis Terra. A spectacular dune ridge and other dune forms on the crater floor have caused extensive imaging. The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 59591 Latitude: -54.471 Longitude: 13.1288 Instrument: VIS Captured: 2015-05-21 10:57 https://photojournal.jpl.nasa.gov/catalog/PIA21808

Terra MODIS Band 27 Electronic Crosstalk Effect and Its Removal

NASA Technical Reports Server (NTRS)

Sun, Junqiang; Xiong, Xiaoxiong; Madhavan, Sriharsha; Wenny, Brian

2012-01-01

The MODerate-resolution Imaging Spectroradiometer (MODIS) is one of the primary instruments in the NASA Earth Observing System (EOS). The first MODIS instrument was launched in December, 1999 on-board the Terra spacecraft. MODIS has 36 bands, covering a wavelength range from 0.4 micron to 14.4 micron. MODIS band 27 (6.72 micron) is a water vapor band, which is designed to be insensitive to Earth surface features. In recent Earth View (EV) images of Terra band 27, surface feature contamination is clearly seen and striping has become very pronounced. In this paper, it is shown that band 27 is impacted by electronic crosstalk from bands 28-30. An algorithm using a linear approximation is developed to correct the crosstalk effect. The crosstalk coefficients are derived from Terra MODIS lunar observations. They show that the crosstalk is strongly detector dependent and the crosstalk pattern has changed dramatically since launch. The crosstalk contributions are positive to the instrument response of band 27 early in the mission but became negative and much larger in magnitude at later stages of the mission for most detectors of the band. The algorithm is applied to both Black Body (BB) calibration and MODIS L1B products. With the crosstalk effect removed, the calibration coefficients of Terra MODIS band 27 derived from the BB show that the detector differences become smaller. With the algorithm applied to MODIS L1B products, the Earth surface features are significantly removed and the striping is substantially reduced in the images of the band. The approach developed in this report for removal of the electronic crosstalk effect can be applied to other MODIS bands if similar crosstalk behaviors occur.

Mars Observer Lecture: Mars Orbit Insertion

NASA Technical Reports Server (NTRS)

Dodd, Suzanne R. (Personal Name)

1993-01-01

The Mars Observer mission spacecraft was primarily designed for exploring Mars and the Martian environment. The Mars Observer was launched on September 25, 1992. The spacecraft was lost in the vicinity of Mars on August 21, 1993 when the spacecraft began its maneuvering sequence for Martian orbital insertion. This videotape shows a lecture by Suzanne R. Dodd, the Mission Planning Team Chief for the Mars Observer Project. Ms Dodd begins with a brief overview of the mission and the timeline from the launch to orbital insertion. Ms Dodd then reviews slides showing the trajectory of the spacecraft on its trip to Mars. Slides of the spacecraft being constructed are also shown. She then discusses the Mars orbit insertion and the events that will occur to move the spacecraft from the capture orbit into a mapping orbit. During the trip to Mars, scientists at JPL had devised a new strategy, called Power In that would allow for an earlier insertion into the mapping orbit. The talk summarizes this strategy, showing on a slide the planned transition orbits. There are shots of the Martian moon, Phobos, taken from the Viking spacecraft, as Ms Dodd explains that the trajectory will allow the orbiter to make new observations of that moon. She also explains the required steps to prepare for mapping after the spacecraft has achieved the mapping orbit around Mars. The lecture ends with a picture of Mars from the Observer on its approach to the planet.

CRISM's Global Mapping of Mars, Part 1

NASA Technical Reports Server (NTRS)

2007-01-01

750, one of 209 tiles just delivered to the PDS. It shows a part of the planet called Tyrrhena Terra in the ancient, heavily cratered highlands. The colored strips are CRISM multispectral survey data acquired over several months, in which each pixel has a calibrated 72-color spectrum of Mars. The three wavelengths shown are 2.53, 1.50, and 1.08 micrometers in the red, green, and blue image planes respectively. At these wavelengths, rocky areas appear brown, dusty areas appear tan, and regions with hazy atmosphere appear bluish. Note that there is a large difference in brightness between strips, because there is no correction for the lighting conditions at the time of each observation. The gray areas between the strips are from an earlier mosaic of the planet taken by the Thermal Emission Imaging System (THEMIS) instrument on Mars Odyssey, and are included only for context. Ultimately the multispectral survey will cover nearly all of this area.

CRISM is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter and the Mars Science Laboratory for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter.

CRISM's Global Mapping of Mars, Part 2

NASA Technical Reports Server (NTRS)

2007-01-01

750, one of 209 tiles just delivered to the PDS. It shows a part of the planet called Tyrrhena Terra in the ancient, heavily cratered highlands. The colored strips are CRISM multispectral survey data acquired over several months, in which each pixel has a calibrated 72-color spectrum of Mars. The three wavelengths shown are 2.53, 1.50, and 1.08 micrometers in the red, green, and blue image planes respectively. At these wavelengths, rocky areas appear brown, dusty areas appear tan, and regions with hazy atmosphere appear bluish. Note that there is a large difference in brightness between strips, because there is no correction for the lighting conditions at the time of each observation. The gray areas between the strips are from an earlier mosaic of the planet taken by the Thermal Emission Imaging System (THEMIS) instrument on Mars Odyssey, and are included only for context. Ultimately the multispectral survey will cover nearly all of this area.

CRISM is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter and the Mars Science Laboratory for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter.

Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus

NASA Technical Reports Server (NTRS)

Kumar, P. Senthil; Head, James W., III

2009-01-01

Geological mapping of the V-56 quadrangle (Fig. 1) reveals various tectonic and volcanic features and processes in Lada Terra that consist of tesserae, regional extensional belts, coronae, volcanic plains and impact craters. This study aims to map the spatial distribution of different material units, deformational features or lineament patterns and impact crater materials. In addition, we also establish the relative age relationships (e.g., overlapping or cross-cutting relationship) between them, in order to reconstruct the geologic history. Basically, this quadrangle addresses how coronae evolved in association with regional extensional belts, in addition to evolution of tesserae, regional plains and impact craters, which are also significant geological units of Lada Terra.

TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958-2015.

PubMed

Abatzoglou, John T; Dobrowski, Solomon Z; Parks, Sean A; Hegewisch, Katherine C

2018-01-09

We present TerraClimate, a dataset of high-spatial resolution (1/24°, ~4-km) monthly climate and climatic water balance for global terrestrial surfaces from 1958-2015. TerraClimate uses climatically aided interpolation, combining high-spatial resolution climatological normals from the WorldClim dataset, with coarser resolution time varying (i.e., monthly) data from other sources to produce a monthly dataset of precipitation, maximum and minimum temperature, wind speed, vapor pressure, and solar radiation. TerraClimate additionally produces monthly surface water balance datasets using a water balance model that incorporates reference evapotranspiration, precipitation, temperature, and interpolated plant extractable soil water capacity. These data provide important inputs for ecological and hydrological studies at global scales that require high spatial resolution and time varying climate and climatic water balance data. We validated spatiotemporal aspects of TerraClimate using annual temperature, precipitation, and calculated reference evapotranspiration from station data, as well as annual runoff from streamflow gauges. TerraClimate datasets showed noted improvement in overall mean absolute error and increased spatial realism relative to coarser resolution gridded datasets.

TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958-2015

NASA Astrophysics Data System (ADS)

Abatzoglou, John T.; Dobrowski, Solomon Z.; Parks, Sean A.; Hegewisch, Katherine C.

2018-01-01

We present TerraClimate, a dataset of high-spatial resolution (1/24°, ~4-km) monthly climate and climatic water balance for global terrestrial surfaces from 1958-2015. TerraClimate uses climatically aided interpolation, combining high-spatial resolution climatological normals from the WorldClim dataset, with coarser resolution time varying (i.e., monthly) data from other sources to produce a monthly dataset of precipitation, maximum and minimum temperature, wind speed, vapor pressure, and solar radiation. TerraClimate additionally produces monthly surface water balance datasets using a water balance model that incorporates reference evapotranspiration, precipitation, temperature, and interpolated plant extractable soil water capacity. These data provide important inputs for ecological and hydrological studies at global scales that require high spatial resolution and time varying climate and climatic water balance data. We validated spatiotemporal aspects of TerraClimate using annual temperature, precipitation, and calculated reference evapotranspiration from station data, as well as annual runoff from streamflow gauges. TerraClimate datasets showed noted improvement in overall mean absolute error and increased spatial realism relative to coarser resolution gridded datasets.

Multiple Introductions of Dengue 2 Virus Strains into Saudi Arabia from 1992 to 2014.

PubMed

El-Kafrawy, Sherif A; Sohrab, Sayed S; Ela, Said Abol; Abd-Alla, Adly M M; Alhabbab, Rowa; Farraj, Suha A; Othman, Norah A; Hassan, Ahmed M; Bergoin, Max; Klitting, Raphaelle; Charrel, Remi N; Hashem, Anwar M; Madani, Tariq A; Azhar, Esam I

2016-06-01

Dengue is a significant arboviral infection that represents a major public health concern worldwide. The infection is endemic in most parts of South East Asia, sub-Saharan Africa, and Latin America. Among the four dengue virus (DENV) serotypes, DENV-2 has been reported to be the predominant serotype in Saudi Arabia since 1992. However, virological and epidemiological data of DENV-2 from Saudi Arabia are severely deficient and require further investigations. Full genome sequencing of a recent DENV-2 isolate and phylogenetic analysis of all available DENV-2 sequences from Saudi Arabia. Based on full genome and envelope (E) gene sequence, we show that a recent isolate (DENV-2-Jeddah-2014) belongs to the Indian subcontinent lineage of the Cosmopolitan genotype with close similarity to recent strains from Pakistan. Interestingly, the E gene sequence of DENV-2-Jeddah-2014 isolate was slightly divergent from those previously identified in Saudi Arabia between 1992 and 2004 with three to nine amino acid (aa) substitutions. While our data show that the Cosmopolitan genotype is still circulating in Saudi Arabia, they highlight four distinct genetic groups suggesting at least four independent introductions into the Kingdom. The close clustering of DENV-2 isolates reported from Saudi Arabia between 1992 and 2014 with strains from countries providing the highest numbers of pilgrims attending either Hajj or Umrah pilgrimages (Indonesia, Pakistan, India) clearly suggests a role for pilgrims or expatriates coming from DENV endemic countries in DENV-2 importation into Saudi Arabia. Accordingly, continuous monitoring of the circulation of DENVs in Saudi Arabia must be implemented to undertake effective control and management strategies in the Kingdom. Screening of the pilgrims coming to perform Hajj and Umrah might help prevent the introduction of new DENV strains, which is expected to increase the burden of the disease not only in Saudi Arabia but also in other countries.

77 FR 53959 - Culturally Significant Objects Imported for Exhibition Determinations: “Roads of Arabia...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-04

... Determinations: ``Roads of Arabia: Archaeology and the History of the Kingdom of Saudi Arabia'' SUMMARY: Notice... objects to be included in the exhibition ``Roads of Arabia: Archaeology and the History of the Kingdom of..., 2013; the Museum of Fine Arts, Houston in Houston, Texas from on or about November 15, 2013 until on or...

Deflections in Lava Flow Directions Relative to Topography in the Tharsis Region of Mars: Indications of Post-Flow Tectonic Motion

NASA Technical Reports Server (NTRS)

Chadwick, D. J.; Hughes, S. S.; Sakimoto, S. E. H.

2004-01-01

High-resolution topographic data from the Mars Orbiter Laser Altimeter (MOLA), and imagery from the Mars Orbiter Camera (MOC) and the Thermal Emission Imaging System (THEMIS) allow for the first accurate assessment of lava flow directions relative to topographic slopes in the Tharsis region. Tharisis has long been recognized as the dominant tectonic and volcanic province on the planet, with a complex geologic history. In this study, lava flow directions on Daedalia Planum, Syria Planum, Tempe Terra, and near the Tharsis Montes are compared with MOLA topographic contours to look for deviations of flow directions from the local slope direction. The topographic deviations identified in this study are likely due to Tharsis tectonic deformation that has modified the regional topography subsequent to the emplacement of the flows, and can be used to model the mechanisms and magnitudes of relatively recent tectonism in the region. A similar approach was used to identify possible post-flow tectonic subsidence on the Snake River Plain in Idaho.

Styles of deformation in Ishtar Terra and their implications

NASA Astrophysics Data System (ADS)

Kaula, William M.; Bindschadler, Duane L.; Grimm, Robert E.; Hansen, Vicki L.; Roberts, Kari M.; Smrekar, Suzanne E.

1992-10-01

Styles of deformation in Ishtar Terra are examined on the basis of imaging by the Magellan radar between the start of the mission and the start of the first superior conjunction hiatus. Ishtar Terra appears to have characteristics of both plume uplifts and convergent belts, and exhibits a great variety of tectonic and volcanic activity, with large variations within distances of only a few hundred kilometers. The most prominent terrain types are the volcanic plains of Lakshmi and the mountain belts of Maxwell, Freyja, and Danu. Ishtar demonstrates three general properties of Venus. Erosional degradation is absent, leading to the preservation of patterns resulting from past activity. Many surface features are the responses of a competent layer less than 10 km thick to flows of 100 km or broader scale. These broader scale flows are controlled mainly by heterogeneities in the mantle.

Styles of deformation in Ishtar Terra and their implications

NASA Technical Reports Server (NTRS)

Kaula, William M.; Bindschadler, Duane L.; Grimm, Robert E.; Hansen, Vicki L.; Roberts, Kari M.; Smrekar, Suzanne E.

1992-01-01

Styles of deformation in Ishtar Terra are examined on the basis of imaging by the Magellan radar between the start of the mission and the start of the first superior conjunction hiatus. Ishtar Terra appears to have characteristics of both plume uplifts and convergent belts, and exhibits a great variety of tectonic and volcanic activity, with large variations within distances of only a few hundred kilometers. The most prominent terrain types are the volcanic plains of Lakshmi and the mountain belts of Maxwell, Freyja, and Danu. Ishtar demonstrates three general properties of Venus. Erosional degradation is absent, leading to the preservation of patterns resulting from past activity. Many surface features are the responses of a competent layer less than 10 km thick to flows of 100 km or broader scale. These broader scale flows are controlled mainly by heterogeneities in the mantle.

CERES BiDirectional Scans (BDS) data in HDF (CER_BDS_Terra-FM1_Edition1-CV)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

Each BiDirectional Scans (BDS) data product contains twenty-four hours of Level-1b data for each CERES scanner instrument mounted on each spacecraft. The BDS includes samples taken in normal and short Earth scan elevation profiles in both fixed and rotating azimuth scan modes (including space, internal calibration, and solar calibration views). The BDS contains Level-0 raw (unconverted) science and instrument data as well as the geolocated converted science and instrument data. The BDS contains additional data not found in the Level-0 input file, including converted satellite position and velocity data, celestial data, converted digital status data, and parameters used in the radiance count conversion equations. The following CERES BDS data sets are currently available: CER_BDS_TRMM-PFM_Edition1 CER_BDS_Terra-FM1_Edition1 CER_BDS_Terra-FM2_Edition1 CER_BDS_Terra-FM1_Edition2 CER_BDS_Terra-FM2_Edition2 CER_BDS_Aqua-FM3_Edition1 CER_BDS_Aqua-FM4_Edition1 CER_BDS_Aqua-FM3_Edition2 CER_BDS_Aqua-FM4_Edition2 CER_BDS_Aqua-FM3_Edition1-CV CER_BDS_Aqua-FM4_Edition1-CV CER_BDS_Terra-FM1_Edition1-CV CER_BDS_Terra-FM2_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-11-02] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

Gravity anomalies, compensation mechanisms, and the geodynamics of western Ishtar Terra, Venus

NASA Technical Reports Server (NTRS)

Grimm, Robert E.; Phillips, Roger J.

1991-01-01

Pioneer Venus line-of-sight orbital accelerations were utilized to calculate the geoid and vertical gravity anomalies for western Ishtar Terra on various planes of altitude z sub 0. The apparent depth of isostatic compensation at z sub 0 = 1400 km is 180 + or - 20 km based on the usual method of minimum variance in the isostatic anomaly. An attempt is made here to explain this observation, as well as the regional elevation, peripheral mountain belts, and inferred age of western Ishtar Terra, in terms of one or three broad geodynamic models.

Mars Pathfinder and Mars Global Surveyor Outreach Compilation

NASA Astrophysics Data System (ADS)

1999-09-01

This videotape is a compilation of the best NASA JPL (Jet Propulsion Laboratory) videos of the Mars Pathfinder and Mars Global Surveyor missions. The mission is described using animation and narration as well as some actual footage of the entire sequence of mission events. Included within these animations are the spacecraft orbit insertion; descent to the Mars surface; deployment of the airbags and instruments; and exploration by Sojourner, the Mars rover. JPL activities at spacecraft control during significant mission events are also included at the end. The spacecraft cameras pan the surrounding Mars terrain and film Sojourner traversing the surface and inspecting rocks. A single, brief, processed image of the Cydonia region (Mars face) at an oblique angle from the Mars Global Surveyor is presented. A description of the Mars Pathfinder mission, instruments, landing and deployment process, Mars approach, spacecraft orbit insertion, rover operation are all described using computer animation. Actual color footage of Sojourner as well as a 360 deg pan of the Mars terrain surrounding the spacecraft is provided. Lower quality black and white photography depicting Sojourner traversing the Mars surface and inspecting Martian rocks also is included.

Mars Pathfinder and Mars Global Surveyor Outreach Compilation

NASA Technical Reports Server (NTRS)

1999-01-01

This videotape is a compilation of the best NASA JPL (Jet Propulsion Laboratory) videos of the Mars Pathfinder and Mars Global Surveyor missions. The mission is described using animation and narration as well as some actual footage of the entire sequence of mission events. Included within these animations are the spacecraft orbit insertion; descent to the Mars surface; deployment of the airbags and instruments; and exploration by Sojourner, the Mars rover. JPL activities at spacecraft control during significant mission events are also included at the end. The spacecraft cameras pan the surrounding Mars terrain and film Sojourner traversing the surface and inspecting rocks. A single, brief, processed image of the Cydonia region (Mars face) at an oblique angle from the Mars Global Surveyor is presented. A description of the Mars Pathfinder mission, instruments, landing and deployment process, Mars approach, spacecraft orbit insertion, rover operation are all described using computer animation. Actual color footage of Sojourner as well as a 360 deg pan of the Mars terrain surrounding the spacecraft is provided. Lower quality black and white photography depicting Sojourner traversing the Mars surface and inspecting Martian rocks also is included.

Pharmacy education in Saudi Arabia: The past, the present, and the future.

PubMed

Alhamoudi, Abdulhakem; Alnattah, Ashraf

Saudi Arabia has a population of approximately 31 million people. The amount of literature published regarding pharmacy education in Saudi Arabia, however, is insignificant in number. The objective of this study is to describe the condition of pharmacy education in Saudi Arabia. PubMed, Saudi Arabian government's publications and websites of pharmacy colleges have been searched. Descriptive content analysis has been used to draw a complete picture of pharmacy education in Saudi Arabia. From 1959 to 2001, Saudi Arabia had only one college of pharmacy. However, from 2001 to 2014, with the government initiative to train more national pharmacists, the nation witnessed the establishment of 23 government colleges and seven private colleges. No new colleges have been established since 2014. By the end of 2014, there were 30 pharmacy colleges offering more than 37 undergraduate programs. Only three colleges offer postgraduate programs, however. None of the colleges are accredited nationally or internationally. There is no evidence that this increase in the number of pharmacy colleges will meet the demand for nationally-born pharmacists. More research needs to be conducted concerning Saudi Arabia's need. There are very few opportunities for advanced degrees. The program names should be a normalized as all of them lead to registration as a pharmacist. The dramatic increase may have affected program quality as no colleges are nationally or internationally accredited. Colleges should seek accreditation to ensure they are within accepted international standards. Copyright © 2017 Elsevier Inc. All rights reserved.

Cross-calibration of the Oceansat-2 Ocean Colour Monitor (OCM) with Terra and Aqua MODIS

NASA Astrophysics Data System (ADS)

Angal, Amit; Brinkmann, Jake; Kumar, A. Senthil; Xiong, Xiaoxiong

2016-05-01

The Ocean Colour Monitor (OCM) sensor on-board the Oceansat-2 spacecraft has been operational since its launch in September, 2009. The Oceansat 2 OCM primary design goal is to provide continuity to Oceansat-1 OCM to obtain information regarding various ocean-colour variables. OCM acquires Earth scene measurements in eight multi-spectral bands in the range from 402 to 885 nm. The MODIS sensor on the Terra and Aqua spacecraft has been successfully operating for over a decade collecting measurements of the earth's land, ocean surface and atmosphere. The MODIS spectral bands, designed for land and ocean applications, cover the spectral range from 412 to 869 nm. This study focuses on comparing the radiometric calibration stability of OCM using near-simultaneous TOA measurements with Terra and Aqua MODIS acquired over the Libya 4 target. Same-day scene-pairs from all three sensors (OCM, Terra and Aqua MODIS) between August, 2014 and September, 2015 were chosen for this analysis. On a given day, the OCM overpass is approximately an hour after the Terra overpass and an hour before the Aqua overpass. Due to the orbital differences between Terra and Aqua, MODIS images the Libya 4 site at different scan-angles on a given day. Some of the high-gain ocean bands for MODIS tend to saturate while viewing the bright Libya 4 target, but bands 8-10 (412 nm - 486 nm) provide an unsaturated response and are used for comparison with the spectrally similar OCM bands. All the standard corrections such as bidirectional reflectance factor (BRDF), relative spectral response mismatch, and impact for atmospheric water-vapor are applied to obtain the reflectance differences between OCM and the two MODIS instruments. Furthermore, OCM is used as a transfer radiometer to obtain the calibration differences between Terra and Aqua MODIS reflective solar bands.

Cross-Calibration of the Oceansat-2 Ocean Colour Monitor (OCM) with Terra and Aqua MODIS

NASA Technical Reports Server (NTRS)

Angal, Amit; Brinkmann, Jake; Kumar, A. Senthil; Xiong, Xiaoxiong

2016-01-01

The Ocean Colour Monitor (OCM) sensor on-board the Oceansat-2 spacecraft has been operational since its launch in September, 2009. The Oceansat 2 OCM primary design goal is to provide continuity to Oceansat-1 OCM to obtain information regarding various ocean-colour variables. OCM acquires Earth scene measurements in eight multi-spectral bands in the range from 402 to 885 nm. The MODIS sensor on the Terra and Aqua spacecraft has been successfully operating for over a decade collecting measurements of the earth's land, ocean surface and atmosphere. The MODIS spectral bands, designed for land and ocean applications, cover the spectral range from 412 to 869 nm. This study focuses on comparing the radiometric calibration stability of OCM using near-simultaneous TOA measurements with Terra and Aqua MODIS acquired over the Libya 4 target. Same-day scene-pairs from all three sensors (OCM, Terra and Aqua MODIS) between August, 2014 and September, 2015 were chosen for this analysis. On a given day, the OCM overpass is approximately an hour after the Terra overpass and an hour before the Aqua overpass. Due to the orbital differences between Terra and Aqua, MODIS images the Libya 4 site at different scan-angles on a given day. Some of the high-gain ocean bands for MODIS tend to saturate while viewing the bright Libya 4 target, but bands 8-10 (412 nm - 486 nm) provide an unsaturated response and are used for comparison with the spectrally similar OCM bands. All the standard corrections such as bidirectional reflectance factor (BRDF), relative spectral response mismatch, and impact for atmospheric water-vapor are applied to obtain the reflectance differences between OCM and the two MODIS instruments. Furthermore, OCM is used as a transfer radiometer to obtain the calibration differences between Terra and Aqua MODIS reflective solar bands.

Gender inequity in Saudi Arabia and its role in public health.

PubMed

Mobaraki, A E H; Söderfeldt, B

2010-01-01

In Saudi Arabia, local interpretations of Islamic laws and social norms have a negative impact on the health and well-being of women. The objective of this literature review was to discuss gender inequity in Saudi Arabia and its relation to public health. Despite the scarcity of recent statistics and information regarding gender inequity in Saudi Arabia, this review is an attempt to explore this sensitive issue in this country. Women's roles and rights in Saudi society were examined, including education, marriage, polygamy, fertility, job opportunities, car driving and identification cards. Further research to assess knowledge, attitudes and practices towards health care of Saudi men and women is recommended.

State of the scientific knowledge on properties and genesis of Anthropogenic Dark Earths in Central Amazonia (terra preta de Índio)

NASA Astrophysics Data System (ADS)

Glaser, Bruno; Birk, Jago Jonathan

2012-04-01

Tropical rainforests are highly important for the global climate regulation and for global biodiversity. However, these ecosystems are characterized by nutrient-poor and highly weathered soils and by high turnover rates of organic matter. Thus, they are fragile ecosystems prone to loss of ecosystem services when anthropogenically disturbed. Currently, the major threat to these ecosystems is deforestation leading to irreversible destruction of rainforests. Surprising and not expected is that within these ecosystems small patches of highly fertile soils occur which are known as Anthropogenic Dark Earths or terra preta de Índio (terra preta). These soils exhibit high nutrient and soil organic matter stocks and allow sustainable agriculture. Frequent occurrence of pot-sherds of pre-Columbian origin and further evidence for settlement activities clearly demonstrate that terra preta is of anthropogenic origin. In recent years, the terra preta phenomenon has gained increasing interest because it is assumed that terra preta could act as a model for promoting sustainable agricultural practices in the humid tropics and because terra preta is an example for long-term CO2 sequestration into terrestrial ecosystems with additional positive benefits for ecosystem services. These potentials of terra preta initiated a great number of studies but also stimulated fantasy about their genesis. Therefore, the aim of this review is to summarize the scientific knowledge about terra preta properties and to discuss their genesis. From our own and literature data it is evident that terra preta is the product of inorganic [e.g. ash, bones (esp. fish)] and organic (e.g. biomass wastes, manure, excrements, urine, and biochar) amendments to infertile Ferralsols. These ingredients were microbially metabolized and stabilized by humification in soil, fungi playing a bigger role in this process compared to bacteria in surrounding ecosystems. Biochar is a key component for this process due to its

Magnetic Strips Preserve Record of Ancient Mars

NASA Technical Reports Server (NTRS)

1999-01-01

This image is a map of Martian magnetic fields in the southern highlands near the Terra Cimmeria and Terra Sirenum regions, centered around 180 degrees longitude from the equator to the pole. It is where magnetic stripes possibly resulting from crustal movement are most prominent. The bands are oriented approximately east - west and are about 100 miles wide and 600 miles long, although the longest band stretches more than 1200 miles. The false blue and red colors represent invisible magnetic fields in the Martian crust that point in opposite directions. The magnetic fields appear to be organized in bands, with adjacent bands pointing in opposite directions, giving these stripes a striking similarity to patterns seen in the Earth's crust at the mid-oceanic ridges.

NASA's Mars Global Surveyor has discovered surprising new evidence of past movement of the Martian crust, suggesting that ancient Mars was a more dynamic, Earth-like planet than it is today.

Scientists using the spacecraft's magnetometer have found banded patterns of magnetic fields on the Martian surface. The adjacent magnetic bands point in opposite directions, giving these invisible stripes a striking similarity to patterns seen in the crust of Earth's sea floors.

[figure removed for brevity, see original site] (P50330,MRPS94769)

Above: An artist's concept comparing the present day magnetic fields on Earth and Mars. Earth's magnetic field is generated by an active dynamo - a hot core of molten metal. The magnetic field surrounds Earth and is considered global (left). The various Martian magnetic fields (right) do not encompass the entire planet and are local. The Martian dynamo is extinct, and its magnetic fields are 'fossil' remnants of its ancient, global magnetic field. I

On the Earth, the sea floor spreads apart slowly at mid-oceanic ridges as new crust flows up from Earth's hot interior. Meanwhile, the direction of Earth's magnetic field reverses occasionally, resulting in

Characteristics of Impact Craters and Interior Deposits: Analysis of the Spatial and Temporal Distribution of Volatiles in the Highlands of Mars

NASA Technical Reports Server (NTRS)

Mest, S. C.

2005-01-01

The martian southern highlands contain impact craters that display pristine to degraded morphologies, and preserve a record of degradation that can be attributed to fluvial, eolian, mass wasting, volcanic and impact-related processes. However, the relative degree of modification by these processes and the amounts of material contributed to crater interiors are not well constrained. Impact craters (D>10 km) within Terra Cimmeria (0deg-60degS, 190deg-240degW), Terra Tyrrhena (0deg-30degS, 260deg-310degW) and Noachis Terra (20deg-50degS, 310deg-340degW) are being examined to better understand the degradational history and evolution of highland terrains. The following scientific objectives will be accomplished. 1) Determine the geologic processes that modified impact craters (and surrounding highland terrains). 2) Determine the sources (e.g. fluvial, lacustrine, eolian, mass wasting, volcanic, impact melt) and relative amounts of material composing crater interior deposits. 3) Document the relationships between impact crater degradation and highland fluvial systems. 4) Determine the spatial and temporal relationships between degradational processes on local and regional scales. And 5) develop models of impact crater (and highland) degradation that can be applied to these and other areas of the martian highlands. The results of this study will be used to constrain the geologic, hydrologic and climatic evolution of Mars and identify environments in which subsurface water might be present or evidence for biologic activity might be preserved.

Ground Displacement Measurement of the 2013 Balochistan Earthquake with interferometric TerraSAR-X ScanSAR data

NASA Astrophysics Data System (ADS)

Yague-Martinez, N.; Fielding, E. J.; Haghshenas-Haghighi, M.; Cong, X.; Motagh, M.

2014-12-01

This presentation will address the 24 September 2013 Mw 7.7 Balochistan Earthquake in western Pakistan from the point of view of interferometric processing algorithms of wide-swath TerraSAR-X ScanSAR images. The algorithms are also valid for TOPS acquisition mode, the operational mode of the Sentinel-1A ESA satellite that was successfully launched in April 2014. Spectral properties of burst-mode data and an overview of the interferometric processing steps of burst-mode acquisitions, emphasizing the importance of the co-registration stage, will be provided. A co-registration approach based on incoherent cross-correlation will be presented and applied to seismic scenarios. Moreover geodynamic corrections due to differential atmospheric path delay and differential solid Earth tides are considered to achieve accuracy in the order of several centimeters. We previously derived a 3D displacement map using cross-correlation techniques applied to optical images from Landsat-8 satellite and TerraSAR-X ScanSAR amplitude images. The Landsat-8 cross-correlation measurements cover two horizontal directions, and the TerraSAR-X displacements include both horizontal along-track and slant-range (radar line-of-sight) measurements that are sensitive to vertical and horizontal deformation. It will be justified that the co-seismic displacement map from TerraSAR-X ScanSAR data may be contaminated by postseismic deformation due to the fact that the post-seismic acquisition took place one month after the main shock, confirmed in part by a TerraSAR-X stripmap interferogram (processed with conventional InSAR) covering part of the area starting on 27 September 2013. We have arranged the acquisition of a burst-synchronized stack of TerraSAR-X ScanSAR images over the affected area after the earthquake. It will be possible to apply interferometry to these data to measure the lower magnitude of the expected postseismic displacements. The processing of single interferograms will be discussed. A

TerraFERMA: The Transparent Finite Element Rapid Model Assembler for multi-physics problems in the solid Earth sciences

NASA Astrophysics Data System (ADS)

Spiegelman, M. W.; Wilson, C. R.; Van Keken, P. E.

2013-12-01

We announce the release of a new software infrastructure, TerraFERMA, the Transparent Finite Element Rapid Model Assembler for the exploration and solution of coupled multi-physics problems. The design of TerraFERMA is driven by two overarching computational needs in Earth sciences. The first is the need for increased flexibility in both problem description and solution strategies for coupled problems where small changes in model assumptions can often lead to dramatic changes in physical behavior. The second is the need for software and models that are more transparent so that results can be verified, reproduced and modified in a manner such that the best ideas in computation and earth science can be more easily shared and reused. TerraFERMA leverages three advanced open-source libraries for scientific computation that provide high level problem description (FEniCS), composable solvers for coupled multi-physics problems (PETSc) and a science neutral options handling system (SPuD) that allows the hierarchical management of all model options. TerraFERMA integrates these libraries into an easier to use interface that organizes the scientific and computational choices required in a model into a single options file, from which a custom compiled application is generated and run. Because all models share the same infrastructure, models become more reusable and reproducible. TerraFERMA inherits much of its functionality from the underlying libraries. It currently solves partial differential equations (PDE) using finite element methods on simplicial meshes of triangles (2D) and tetrahedra (3D). The software is particularly well suited for non-linear problems with complex coupling between components. We demonstrate the design and utility of TerraFERMA through examples of thermal convection and magma dynamics. TerraFERMA has been tested successfully against over 45 benchmark problems from 7 publications in incompressible and compressible convection, magmatic solitary waves

Tracking the India-Arabia Transform Plate Boundary during Paleogene Times.

NASA Astrophysics Data System (ADS)

Rodriguez, M.; Huchon, P.; Chamot-Rooke, N. R. A.; Fournier, M.; Delescluse, M.

2014-12-01

The Zagros and Himalaya mountain belts are the most prominent reliefs built by continental collision. They respectively result from Arabia and India collision with Eurasia. Convergence motions at mountain belts induced most of plate reorganization events in the Indian Ocean during the Cenozoic. Although critical for paleogeographic reconstructions, the way relative motion between Arabia and India was accommodated prior to the formation of the Sheba ridge in the Gulf of Aden remains poorly understood. The India-Arabia plate-boundary belongs to the category of long-lived (~90-Ma) oceanic transform faults, thus providing a good case study to investigate the role of major kinematic events over the structural evolution of a long-lived transform system. A seismic dataset crossing the Owen Fracture Zone, the Owen Basin, and the Oman Margin was acquired to track the past locations of the India-Arabia plate boundary. We highlight the composite age of the Owen Basin basement, made of Paleocene oceanic crust drilled on its eastern part, and composed of pre-Maastrichtian continental crust overlaid by Early Paleocene ophiolites on its western side. A major transform fault system crossing the Owen Basin juxtaposed these two slivers of lithosphere of different ages, and controlled the uplift of marginal ridges along the Oman Margin. This transform system deactivated ~40 Ma ago, coeval with the onset of ultra-slow spreading at the Carlsberg Ridge. The transform boundary then jumped to the edge of the present-day Owen Ridge during the Late Eocene-Oligocene period, before seafloor spreading began at the Sheba Ridge. This migration of the plate boundary involved the transfer of a part of the Indian oceanic lithosphere accreted at the Carlsberg Ridge to the Arabian plate. The episode of plate transfer at the India-Arabia plate boundary during the Late Eocene-Oligocene interval is synchronous with a global plate reorganization event corresponding to geological events at the Zagros and

Are Clay Minerals a Climate Constraint? A Review of Prior Data and New Insights on Martian "Weathering Sequences"

NASA Astrophysics Data System (ADS)

Ehlmann, B. L.; Dundar, M.

2016-12-01

Most clay minerals on Mars are Fe/Mg smectites or chlorites, which typically form from mafic protoliths in aqueous chemical systems that are relatively closed and thus require liquid water but not large amounts of water throughput and large-scale chemical leaching. They may thus form either in the subsurface or under select conditions at the surface. However, Al clay minerals, discovered in multiple locations on Mars (Arabia Terra, Northeast Syrtis, Libya Montes Terra Sirenum, Eridania, circum-Hellas, Valles Marineris) may provide evidence of substantial water throughput, if their protolith materials were basaltic. This is because formation of Al clays from a mafic protolith requires removal of Mg and either formation of accompanying Fe oxides or removal of Fe. Thus, the observed sequences of Al clays atop Fe/Mg clays were proposed to represent open system weathering and possibly a late climate optimum around the late Noachian/early Hesperian [1]. Later, they were comprehensively cataloged and reported to represent "weathering sequences" similar to those in terrestrial tropical environments [2]. However, key questions remain; in particular, how much water throughput over what time scale is required? The answer to this question has substantial bearing on the climate of early Mars. Recently, we employed a newly developed, non-parametric Bayesian algorithm [3,4] for semi-automatic identification of rare spectral classes on 139 CRISM images in areas with reported regional-scale occurrences of Al clays. Dozens of detections of the minerals alunite and jarosite were made with the algorithm and then verified by manual analysis. These sulfate hydroxides form only at low pHs, and thus their presence tightly constrains water chemistry. Here, we discuss the evidence for low pH surface waters associated with the weathering sequences and their implications for the cumulative duration of surface weathering. [1] Ehlmann et al., 2011, Nature | [2] Carter et al., 2015, Icarus | [3

Nubia-Arabia-Eurasia plate motions and the dynamics of Mediterranean and Middle East tectonics

NASA Astrophysics Data System (ADS)

Reilinger, Robert; McClusky, Simon

2011-09-01

We use geodetic and plate tectonic observations to constrain the tectonic evolution of the Nubia-Arabia-Eurasia plate system. Two phases of slowing of Nubia-Eurasia convergence, each of which resulted in an ˜50 per cent decrease in the rate of convergence, coincided with the initiation of Nubia-Arabia continental rifting along the Red Sea and Somalia-Arabia rifting along the Gulf of Aden at 24 ± 4 Ma, and the initiation of oceanic rifting along the full extent of the Gulf of Aden at 11 ± 2 Ma. In addition, both the northern and southern Red Sea (Nubia-Arabia plate boundary) underwent changes in the configuration of extension at 11 ± 2 Ma, including the transfer of extension from the Suez Rift to the Gulf of Aqaba/Dead Sea fault system in the north, and from the central Red Sea Basin (Bab al Mandab) to the Afar volcanic zone in the south. While Nubia-Eurasia convergence slowed, the rate of Arabia-Eurasia convergence remained constant within the resolution of our observations, and is indistinguishable from the present-day global positioning system rate. The timing of the initial slowing of Nubia-Eurasia convergence (24 ± 4 Ma) corresponds to the initiation of extensional tectonics in the Mediterranean Basin, and the second phase of slowing to changes in the character of Mediterranean extension reported at ˜11 Ma. These observations are consistent with the hypothesis that changes in Nubia-Eurasia convergence, and associated Nubia-Arabia divergence, are the fundamental cause of both Mediterranean and Middle East post-Late Oligocene tectonics. We speculate about the implications of these kinematic relationships for the dynamics of Nubia-Arabia-Eurasia plate interactions, and favour the interpretation that slowing of Nubia-Eurasia convergence, and the resulting tectonic changes in the Mediterranean Basin and Middle East, resulted from a decrease in slab pull from the Arabia-subducted lithosphere across the Nubia-Arabia, evolving plate boundary.

Multiple Introductions of Dengue 2 Virus Strains into Saudi Arabia from 1992 to 2014

PubMed Central

El-Kafrawy, Sherif A.; Sohrab, Sayed S.; Ela, Said Abol; Abd-Alla, Adly M.M.; Alhabbab, Rowa; Farraj, Suha A.; Othman, Norah A.; Hassan, Ahmed M.; Bergoin, Max; Klitting, Raphaelle; Charrel, Remi N.; Hashem, Anwar M.; Madani, Tariq A.

2016-01-01

Abstract Introduction: Dengue is a significant arboviral infection that represents a major public health concern worldwide. The infection is endemic in most parts of South East Asia, sub-Saharan Africa, and Latin America. Among the four dengue virus (DENV) serotypes, DENV-2 has been reported to be the predominant serotype in Saudi Arabia since 1992. However, virological and epidemiological data of DENV-2 from Saudi Arabia are severely deficient and require further investigations. Methods: Full genome sequencing of a recent DENV-2 isolate and phylogenetic analysis of all available DENV-2 sequences from Saudi Arabia. Results: Based on full genome and envelope (E) gene sequence, we show that a recent isolate (DENV-2-Jeddah-2014) belongs to the Indian subcontinent lineage of the Cosmopolitan genotype with close similarity to recent strains from Pakistan. Interestingly, the E gene sequence of DENV-2-Jeddah-2014 isolate was slightly divergent from those previously identified in Saudi Arabia between 1992 and 2004 with three to nine amino acid (aa) substitutions. While our data show that the Cosmopolitan genotype is still circulating in Saudi Arabia, they highlight four distinct genetic groups suggesting at least four independent introductions into the Kingdom. Conclusions: The close clustering of DENV-2 isolates reported from Saudi Arabia between 1992 and 2014 with strains from countries providing the highest numbers of pilgrims attending either Hajj or Umrah pilgrimages (Indonesia, Pakistan, India) clearly suggests a role for pilgrims or expatriates coming from DENV endemic countries in DENV-2 importation into Saudi Arabia. Accordingly, continuous monitoring of the circulation of DENVs in Saudi Arabia must be implemented to undertake effective control and management strategies in the Kingdom. Screening of the pilgrims coming to perform Hajj and Umrah might help prevent the introduction of new DENV strains, which is expected to increase the burden of the disease not only

A reanalysis of ozone on Mars from assimilation of SPICAM observations

NASA Astrophysics Data System (ADS)

Holmes, James A.; Lewis, Stephen R.; Patel, Manish R.; Lefèvre, Franck

2018-03-01

We have assimilated for the first time SPICAM retrievals of total ozone into a Martian global circulation model to provide a global reanalysis of the ozone cycle. Disagreement in total ozone between model prediction and assimilation is observed between 45°S-10°S from LS = 135-180° and at northern polar (60°N-90°N) latitudes during northern fall (LS = 150-195°). Large percentage differences in total ozone at northern fall polar latitudes identified through the assimilation process are linked with excessive northward transport of water vapour west of Tharsis and over Arabia Terra. Modelling biases in water vapour can also explain the underestimation of total ozone between 45°S-10°S from LS = 135-180°. Heterogeneous uptake of odd hydrogen radicals are unable to explain the outstanding underestimation of northern polar total ozone in late northern fall. Assimilation of total ozone retrievals results in alterations of the modelled spatial distribution of ozone in the southern polar winter high altitude ozone layer. This illustrates the potential use of assimilation methods in constraining total ozone where SPICAM cannot observe, in a region where total ozone is especially important for potential investigations of the polar dynamics.

Mars Exploration Rovers: 4 Years on Mars

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2008-01-01

This January, the Mars Exploration Rovers "Spirit" and "Opportunity" are starting their fifth year of exploring the surface of Mars, well over ten times their nominal 90-day design lifetime. This lecture discusses the Mars Exploration Rovers, presents the current mission status for the extended mission, some of the most results from the mission and how it is affecting our current view of Mars, and briefly presents the plans for the coming NASA missions to the surface of Mars and concepts for exploration with robots and humans into the next decade, and beyond.

Visible-NIR Spectroscopic Evidence for the Composition of Low-Albedo Altered Soils on Mars

NASA Astrophysics Data System (ADS)

Murchie, S.; Merenyi, E.; Singer, R.; Kirkland, L.

1996-03-01

Spectroscopic studies of altered Martian soils at visible and at NIR wavelengths have generally supported the canonical model of the surface layer as consisting mostly of 2 components, bright red hematite-containing dust and dark gray pyroxene-containing sand. However several of the studies have also provided tantalizing evidence for distinct 1 micrometer Fe absorptions in discrete areas, particularly dark red soils which are hypothesized to consist of duricrust. These distinct absorptions have been proposed to originate from one or more non-hematitic ferric phases. We have tested this hypothesis by merging high spatial resolution visible- and NIR-wavelength data to synthesize composite 0.44-3.14 1lm spectra for regions of western Arabia and Margaritifer Terra. The extended wavelength coverage allows more complete assessment of ferric, ferrous, and H2O absorptions in both wavelength ranges. The composite data show that, compared to nearby bright red soil in Arabia, dark red soil in Oxia has a lower albedo, a more negative continuum slope, and a stronger 3 micrometer H2O absorption . However Fe absorptions are closely similar in position and depth. These results suggest that at least some dark red soils may differ from "normal" dust and mafic sand more in texture than in Fe mineralogy, although there appears to be enrichment in a water-containing phase and/or a dark, spectrally neutral phase. In contrast, there is clear evidence for enrichment of a low-albedo ferric mineral in dark gray soils composing Sinus Meridiani. These have visible- and NIR-wavelength absorptions consistent with crystalline hematite with relatively little pyroxene, plus a very weak 3 micrometer H2O absorption. These properties suggest a Ethology richer in crystalline hematite and less hydrated than both dust and mafic-rich sand.

Small-scale volcanoes on Mars: distribution and types

NASA Astrophysics Data System (ADS)

Broz, Petr; Hauber, Ernst

2015-04-01

Volcanoes differ in sizes, as does the amount of magma which ascends to a planetary surface. On Earth, the size of volcanoes is anti-correlated with their frequency, i.e. small volcanoes are much more numerous than large ones. The most common terrestrial volcanoes are scoria cones (Mars is a planet which was volcanically active over most (if not all) of its history, a similar distribution of volcano size might be expected. Martian small-scale volcanoes were not intensely studied for a long time due to a lack of high-resolution data enabling their proper identification; however their existence and basic characteristics were predicted on theoretical grounds. Streams of new high-resolution images now enable discovering and studying kilometer-size volcanoes with various shapes in unprecedented detail. Several types of small-scale volcanoes in various regions on Mars were recently described. Scoria cones provide a record of magmatic volatile content and have been identified in Tharsis (Ulysses Colles), on flanks of large volcanoes (e.g., Pavonis Mons), in the caldera of Ulysses Patera, in chaotic terrains or other large depressions (Hydraotes Colles, Coprates Chasma) and in the northern lowlands. Tuff rings and tuff cones, formed as a result of water-magma interaction, seem to be relatively rare on Mars and were only tentatively identified in three locations (Nepenthes/Amenthes region, Arena Colles and inside Lederberg crater), and alternative interpretations (mud volcanoes) seem possible. Other relatively rare volcanoes seem to be lava domes, reported only from two regions (Acracida Planitia and Terra Sirenum). On the other hand, small shields and rootless cones (which are not primary volcanic landforms) represent widely spread phenomena recognized in Tharsis and Elysium. Based on these new observations, the distribution of small volcanoes on Mars seems to be much more widespread than anticipated a decade

Summary of Terra and Aqua MODIS Long-Term Performance

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong (Jack); Wenny, Brian N.; Angal, Amit; Barnes, William; Salomonson, Vincent

2011-01-01

Since launch in December 1999, the MODIS ProtoFlight Model (PFM) onboard the Terra spacecraft has successfully operated for more than 11 years. Its Flight Model (FM) onboard the Aqua spacecraft, launched in May 2002, has also successfully operated for over 9 years. MODIS observations are made in 36 spectral bands at three nadir spatial resolutions and are calibrated and characterized regularly by a set of on-board calibrators (OBC). Nearly 40 science products, supporting a variety of land, ocean, and atmospheric applications, are continuously derived from the calibrated reflectances and radiances of each MODIS instrument and widely distributed to the world-wide user community. Following an overview of MODIS instrument operation and calibration activities, this paper provides a summary of both Terra and Aqua MODIS long-term performance. Special considerations that are critical to maintaining MODIS data quality and beneficial for future missions are also discussed.

Wet Mars, Dry Mars

NASA Astrophysics Data System (ADS)

Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

2012-12-01

The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our lessons learned from evaluations, and show (pictures of) our hands-on activities and 3D models.

Vocational Education to Meet the Needs of a Changing Saudi Arabia.

ERIC Educational Resources Information Center

Campbell, Clifton P.

Faced with sizable oil revenues and the need and desire to expand and diversify its industrial potential, Saudi Arabia is improving its vocational training efforts and attempting to involve as many of its citizens in vocational training programs as possible. At present, Saudi Arabia is having to import skilled workers to keep up with necessary…

Corrections to MODIS Terra Calibration and Polarization Trending Derived from Ocean Color Products

NASA Technical Reports Server (NTRS)

Meister, Gerhard; Eplee, Robert E.; Franz, Bryan A.

2014-01-01

Remotely sensed ocean color products require highly accurate top-of-atmosphere (TOA) radiances, on the order of 0.5% or better. Due to incidents both prelaunch and on-orbit, meeting this requirement has been a consistent problem for the MODIS instrument on the Terra satellite, especially in the later part of the mission. The NASA Ocean Biology Processing Group (OBPG) has developed an approach to correct the TOA radiances of MODIS Terra using spatially and temporally averaged ocean color products from other ocean color sensors (such as the SeaWiFS instrument on Orbview-2 or the MODIS instrument on the Aqua satellite). The latest results suggest that for MODIS Terra, both linear polarization parameters of the Mueller matrix are temporally evolving. A change to the functional form of the scan angle dependence improved the quality of the derived coefficients. Additionally, this paper demonstrates that simultaneously retrieving polarization and gain parameters improves the gain retrieval (versus retrieving the gain parameter only).

Ground Motion Prediction Equations for Western Saudi Arabia from a Reference Model

NASA Astrophysics Data System (ADS)

Kiuchi, R.; Mooney, W. D.; Mori, J. J.; Zahran, H. M.; Al-Raddadi, W.; Youssef, S.

2017-12-01

Western Saudi Arabia is surrounded by several active seismic zones such as the Red Sea and the Gulf of Aqaba where a destructive magnitude 7.3 event occurred in 1995. Over the last decade, the Saudi Geological Survey (SGS) has deployed a dense seismic network that has made it possible to monitor seismic activity more accurately. For example, the network has detected multiple seismic swarms beneath the volcanic fields in western Saudi Arabia. The most recent damaging event was a M5.7 earthquake that occurred in 2009 at Harrat Lunayyir. In terms of seismic hazard assessment, Zahran et al. (2015; 2016) presented a Probabilistic Seismic Hazard Assessment (PSHA) for western Saudi Arabia that was developed using published Ground Motion Prediction Equations (GMPEs) from areas outside of Saudi Arabia. In this study, we consider 41 earthquakes of M 3.0 - 5.4, recorded on 124 stations of the SGS network, to create a set of 442 peak ground acceleration (PGA) and peak ground velocity (PGV) records with a range of epicentral distances from 3 km to 400 km. We use the GMPE model BSSA14 (Boore et al., 2014) as a reference model to estimate our own best-fitting coefficients from a regression analysis using the events occurred in western Saudi Arabia. For epicentral distances less than 100 km, our best fitting model has different source scaling in comparison with the GMPE of BSSA14 adjusted for the California region. In addition, our model indicates that the peak amplitudes have less attenuation in western Saudi Arabia than in California.

17 Years of Cloud Heights from Terra, and Beyond

NASA Astrophysics Data System (ADS)

Davies, R.

2017-12-01

The effective cloud height, H, is the integral of observed cloud-top heights, weighted by their frequency of occurrence. Here we look at changes in the effective cloud height, H', as measured by the Multiangle Imaging Spectroradiometer (MISR) on the first Earth Observing System platform, Terra. Terra was launched in December 1999, and now has over 17 years of consistently measured climate records. Globally, HG' has an important influence on Earth's climate, whereas regionally, HR' is a useful measure of low frequency changes in circulation patterns. MISR has a sampling error in the annual mean HG' of ≈11 m, allowing fairly small interannual variations to be detected. This paper extends the previous 15-year summary that showed significant differences in the long term mean hemispheric cloud height changes. Also of interest are the correlations in tropical cloud height changes and related teleconnections. The largest ephemeral values in the annual HR' [over 1.5 km] are noted over the Central Pacific and the Maritime Continent. These changes are strongly anticorrelated with each other, being directly related to changes in ENSO. They are also correlated with the largest ephemeral changes in HG'. Around the equator, we find at least four distinct centres of similar fluctuations in cloud height. This paper examines the relative time dependence of these regional height changes, separately for La Niña and El Niño events, and stresses the value of extending the time series of uniformly measured cloud heights from space beyond EOS-Terra.

Model of Mars-Bound MarCO CubeSat

NASA Image and Video Library

2015-06-12

Engineers for NASA's MarCO technology demonstration display a full-scale mechanical mock-up of the small craft in development as part of NASA's next mission to Mars. Mechanical engineer Joel Steinkraus and systems engineer Farah Alibay are on the team at NASA's Jet Propulsion Laboratory, Pasadena, California, preparing twin MarCO (Mars Cube One) CubeSats for a March 2016 launch. MarCO is the first interplanetary mission using CubeSat technologies for small spacecraft. The briefcase-size MarCO twins will ride along on an Atlas V launch vehicle lifting off from Vandenberg Air Force Base, California, with NASA's next Mars lander, InSight. The mock-up in the photo is in a configuration to show the deployed position of components that correspond to MarCO's two solar panels and two antennas. During launch, those components will be stowed for a total vehicle size of about 14.4 inches (36.6 centimeters) by 9.5 inches (24.3 centimeters) by 4.6 inches (11.8 centimeters). After launch, the two MarCO CubeSats and InSight will be navigated separately to Mars. The MarCO twins will fly past the planet in September 2016 just as InSight is descending through the atmosphere and landing on the surface. MarCO is a technology demonstration mission to relay communications from InSight to Earth during InSight's descent and landing. InSight communications during that critical period will also be recorded by NASA's Mars Reconnaissance Orbiter for delayed transmission to Earth. InSight -- an acronym for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport -- will study the interior of Mars to improve understanding of the processes that formed and shaped rocky planets, including Earth. After launch, the MarCO twins and InSight will be navigated separately to Mars. Note: After thorough examination, NASA managers have decided to suspend the planned March 2016 launch of the Interior Exploration using Seismic Investigations Geodesy and Heat Transport (InSight) mission

TerraSAR-X Measurements of Wind Fields, Ocean Waves and Currents

NASA Astrophysics Data System (ADS)

Lehner, S.; Schulz-Stellenfleth, J.; Brusch, S.

2008-01-01

TerraSAR-X is a new german X-band radar satellite launched on June 15, 2007. In this mission an operational spaceborne synthetic aperture radar (SAR) system with very high spatial resolution is set up producing remote sensing products for commercial and scientific use. TerraSAR-X is a scientific and technological continuation of the successful Space Shuttle missions SIR-C/X and SRTM.The spacecraft is equipped with a phased array X-band SAR, which can operate in different polarisations and has furthermore beam stearing capabilities. In addition the system has a split antenna mode, which is able to provide along track interferometric information. The instrument is designed for multiple imaging modes like Stripmap, Spotlight and ScanSAR.Due to its polarimetric and interferometric capabilities as well as the high spatial resolution of up to 1 m, the TerraSAR-X sensor is a very interesting tool for oceanography. The presentation will give an overview of several applications, which are of both scientific and commercial interest, like e.g. current and ocean wave measurements, monitoring of morphodynamical processes or high resolution wind field retrieval. The potential as well as limitations of the instrument will be summarized and compared with existing sensors. Necessary steps to translate existing C-band SAR inversion algorithms for wind and wave measurements to X-band will be discussed. A strategy will be outlined to achieve this by a combination of theoretical investigations and the use of existing experimental data acquired by both airborne and groundbased X-band radar. First results on the adaption of existing C-band wind retrieval algorithms will be presented. Wind and ocean wave parameter retrievals will be presented, e.g., based on TerraSAR-X scenes taken over the English channel.

Mars One; creating a human settlement on Mars

NASA Astrophysics Data System (ADS)

Wielders, A.; Lansdorp, B.; Flinkenflögel, S.; Versteeg, B.; Kraft, N.; Vaandrager, E.; Wagensveld, M.; Dogra, A.; Casagrande, B.; Aziz, N.

2013-09-01

Mars One will take humanity to Mars in 2023, to establish a permanent settlement from which human kind will prosper, learn, and grow. Before the first crew lands, Mars One will have established a habitable, sustainable outpost designed to receive new astronauts every two years. To accomplish this, Mars One has developed a precise, realistic plan based entirely upon proven technologies. It is both economically and logistically feasible, and already underway with the aggregation and appointment of hardware suppliers and experts in space exploration. In this paper Mars One discusses the benefits of the mission for planetary science in general and Mars studies in particular. Furthermore potential contributions from the planetary community to the Mars One project will be identified.

Dengue Hemorrhagic Fever Virus in Saudi Arabia: A Review.

PubMed

Al-Tawfiq, Jaffar A; Memish, Ziad A

2018-02-01

Dengue fever is a global disease with a spectrum of clinical manifestation ranging from mild febrile disease to a severe disease in the form of dengue hemorrhagic fever and dengue shock syndrome. Dengue virus is one viral hemorrhagic fever that exists in the Kingdom of Saudi Arabia in addition to Alkhurma (Alkhurma) Hemorrhagic Fever, Chikungunya virus, Crimean-Congo Hemorrhagic Fever, and Rift Valley Fever. The disease is limited to the Western and South-western regions of Saudi Arabia, where Aedes aegypti exists. The majority of the cases in Saudi Arabia had mild disease and is related to serotypes 1-3 but not 4. The prospect for Dengue virus control relies on vector control, health education, and possibly vaccine use. Despite extensive collaborative efforts between multiple governmental sectors, including Ministry of Health, Ministry of Municipalities and Rural Affairs, and Ministry of Water, dengue remains a major public health concern in the regions affected.

Women's Education in Saudi Arabia

ERIC Educational Resources Information Center

Alsuwaida, Nouf

2016-01-01

This paper discusses the historical, political, ideological (value), and government policies of women's education in Saudi Arabia implicated within teaching and learning, how women's higher education has changed over time in the realm of Saudi cultural traditions and religious norms. It also highlights the golden era of women's higher education.…

ESA's Mars Program: European Plans for Mars Exploration

NASA Technical Reports Server (NTRS)

Forget, Francois

2005-01-01

A viewgraph presentation on the European Space Agency Mars Exploration Program is shown. The topics include: 1) History:Mars Exploration in Europe; 2) A few preliminary results from Mars Express; 3) A new instrument:Radar MARSIS; and 4) European Mars Exploration in the future?

Mars Express 10 years at Mars: Observations by the Mars Express Radio Science Experiment (MaRS)

NASA Astrophysics Data System (ADS)

Pätzold, M.; Häusler, B.; Tyler, G. L.; Andert, T.; Asmar, S. W.; Bird, M. K.; Dehant, V.; Hinson, D. P.; Rosenblatt, P.; Simpson, R. A.; Tellmann, S.; Withers, P.; Beuthe, M.; Efimov, A. I.; Hahn, M.; Kahan, D.; Le Maistre, S.; Oschlisniok, J.; Peter, K.; Remus, S.

2016-08-01

The Mars Express spacecraft is operating in Mars orbit since early 2004. The Mars Express Radio Science Experiment (MaRS) employs the spacecraft and ground station radio systems (i) to conduct radio occultations of the atmosphere and ionosphere to obtain vertical profiles of temperature, pressure, neutral number densities and electron density, (ii) to conduct bistatic radar experiments to obtain information on the dielectric and scattering properties of the surface, (iii) to investigate the structure and variation of the crust and lithosphere in selected target areas, (iv) to determine the mass, bulk and internal structure of the moon Phobos, and (v) to track the MEX radio signals during superior solar conjunction to study the morphology of coronal mass ejections (CMEs). Here we report observations, results and discoveries made in the Mars environment between 2004 and 2014 over almost an entire solar cycle.

Extra-terra incognita: Martian maps in the digital age.

PubMed

Messeri, Lisa

2017-02-01

Science and technology studies (STS) and critical cartography are both asking questions about the ontological fixity of maps and other scientific objects. This paper examines how a group of NASA computer scientists who call themselves The Mapmakers conceptualizes and creates maps in service of different commitments. The maps under construction are those of alien Mars, produced through partnerships that NASA has established with Google and Microsoft. With the goal of bringing an experience of Mars to as many people as possible, these maps influence how we imagine our neighbouring planet. This paper analyzes two attributes of the map, evident in both its representation and the attending cartographic practices: a sense of Mars as dynamic and a desire for a democratic experience of Mars in which up-to-date Mars data can be intuitively accessed not only by scientists but by lay users as well. Whereas a democratic Mars promises users the ability to decide how to interact with the map and understand Mars, dynamic Mars imposes a more singular sense of Mars as a target of continued robotic and maybe even human exploration. Because maps of Mars have a different (and arguably less complex) set of social and political commitments than those of Earth, they help us see how different goals contradict and complement each other in matters of exploration and state-craft relevant both to other worlds and our own.

Mars Odyssey Seen by Mars Global Surveyor

NASA Image and Video Library

2005-05-19

This view is an enlargement of an image of NASA Mars Odyssey spacecraft taken by the Mars Orbiter Camera aboard NASA Mars Global Surveyor while the two spacecraft were about 90 kilometers 56 miles apart.

Mars Underground News.

NASA Astrophysics Data System (ADS)

Edgett, K.

Contents: Next entry to Mars (Mars Pathfinder and the microrover Sojourner). Hello, Mars, we're back! Mars Global Surveyor update. The Mars program - 2001 and beyond. Schedule of missions to Mars (as of June 11, 1997). Mars on the Web.

Evaluating Mars Science Laboratory Landing Sites with the Mars Global Reference Atmospheric Model (Mars-GRAM 2005)

NASA Technical Reports Server (NTRS)

Justh, H. L.; Justus, C. G.

2008-01-01

The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL) [1]. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). Mars-GRAM and MGCM use surface topography from Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA), with altitudes referenced to the MOLA areoid, or constant potential surface. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: (1) Thermal Emission Spectrometer (TES) mapping years 1 and 2, with Mars-GRAM data coming from NASA Ames Mars General Circulation Model (MGCM) results driven by observed TES dust optical depth or (2) TES mapping year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from MGCM model results driven by selected values of globally-uniform dust optical depth. Mars-GRAM 2005 has been validated [2] against Radio Science data, and both nadir and limb data from TES [3]. There are several new features included in Mars-GRAM 2005. The first is the option to use input data sets from MGCM model runs that were designed to closely simulate conditions observed during the first two years of TES observations at Mars. The TES Year 1 option includes values from April 1999 through January 2001. The TES Year 2 option includes values from February 2001 through December 2002. The second new feature is the option to read and use any auxiliary profile of temperature and density versus altitude. In exercising the auxiliary profile Mars-GRAM option, values from the auxiliary profile replace data from the original MGCM databases. Some examples of auxiliary profiles include data from TES nadir or limb observations and Mars mesoscale model output at a particular

Innovative Approaches for Seismic Studies of Mars (Invited)

NASA Astrophysics Data System (ADS)

Banerdt, B.

2010-12-01

In addition to its intrinsic interest, Mars is particularly well-suited for studying the full range of processes and phenomena related to early terrestrial planet evolution, from initial differentiation to the start of plate tectonics. It is large and complex enough to have undergone most of the processes that affected early Earth but, unlike the Earth, has apparently not undergone extensive plate tectonics or other major reworking that erased the imprint of early events (as evidenced by the presence of cratered surfaces older than 4 Ga). The martian mantle should have Earth-like polymorphic phase transitions and may even support a perovskite layer near the core (depending on the actual core radius), a characteristic that would have major implications for core cooling and mantle convection. Thus even the most basic measurements of planetary structure, such as crustal thickness, core radius and state (solid/liquid), and gross mantle velocity structure would provide invaluable constraints on models of early planetary evolution. Despite this strong scientific motivation (and several failed attempts), Mars remains terra incognita from a seismic standpoint. This is due to an unfortunate convergence of circumstances, prominent among which are our uncertainty in the level of seismic activity and the relatively high cost of landing multiple long-lived spacecraft on Mars to comprise a seismic network for body-wave travel-time analysis; typically four to ten stations are considered necessary for this type of experiment. In this presentation I will address both of these issues. In order to overcome the concern about a possible lack of marsquakes with which to work, it is useful to identify alternative methods for using seismic techniques to probe the interior. Seismology without quakes can be accomplished in a number of ways. “Unconventional” sources of seismic energy include meteorites (which strike the surface of Mars at a relatively high rate), artificial projectiles

CERES cloud property retrievals from imagers on TRMM, Terra, and Aqua

NASA Astrophysics Data System (ADS)

Minnis, Patrick; Young, David F.; Sun-Mack, Sunny; Heck, Patrick W.; Doelling, David R.; Trepte, Qing Z.

2004-02-01

The micro- and macrophysical properties of clouds play a crucial role in Earth"s radiation budget. The NASA Clouds and Earth"s Radiant Energy System (CERES) is providing simultaneous measurements of the radiation and cloud fields on a global basis to improve the understanding and modeling of the interaction between clouds and radiation at the top of the atmosphere, at the surface, and within the atmosphere. Cloud properties derived for CERES from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites are compared to ensure consistency between the products to ensure the reliability of the retrievals from multiple platforms at different times of day. Comparisons of cloud fraction, height, optical depth, phase, effective particle size, and ice and liquid water paths from the two satellites show excellent consistency. Initial calibration comparisons are also very favorable. Differences between the Aqua and Terra results are generally due to diurnally dependent changes in the clouds. Additional algorithm refinement is needed over the polar regions for Aqua and at night over those same areas for Terra. The results should be extremely valuable for model validation and improvement and for improving our understanding of the relationship between clouds and the radiation budget.

Seismicity of the Tihamat-Asir region, Kingdom of Saudi Arabia

USGS Publications Warehouse

Merghelani, Habib M.

1979-01-01

Knowledge of the seismicity of the west coast of Saudi Arabia is vitally important to the Kingdom. The eastern margin of the Red Sea, which includes all of the west coast of Saudi Arabia, is possibly cut by transform faults that may be capable of producing earthquakes large enough to cause damage in the heavily populated areas or in the industrial complexes under construction. Prior to this study, there were no seismic stations in Saudi Arabia and no studies of microearthquake activity. It was generally assumed that there were no active faults along the west coast. During the period 20 January to 22 February, 1978, five portable seismic stations were deployed in the Tihamat Asir in the southwest part of the country. A significant level of microearthquake activity was detected at a location that approximately coincides with the landward extension of the proposed transform fault. The recording of these earthquakes demonstrates that there are active faults at this location, probably associated with the currently active Red Sea tectonic system. The practical significance of these earthquakes cannot be evaluated from the few data available, and further studies should be undertaken to determine if there are significant seismic hazards along the west coast of Saudi Arabia. 

The respiratory care profession in Saudi Arabia: Past and present

PubMed Central

Al-Otaibi, Hajed M.; AlAhmari, Mohammed Dhafer

2016-01-01

The respiratory care (RC) profession in Saudi Arabia is over 40-year-old. Although there have been major advancements in the profession, no history and enough information are available about its development and evolvement at current. This paper describes the history and development of the field of RC and future prospects for the profession in Saudi Arabia. A comprehensive review and assessment were conducted through direct contact, interviews, and a review of existing documents in the Medical Services Division of the Ministry of Defense, the Ministry of Health, The Ministry of Civil Services, representative hospitals, academic institutions, and other relevant texts. The data obtained were evaluated for its relevance and grouped on a thematic basis. This is currently the first paper about the history and development of the RC profession in Saudi Arabia over the last 45 years. PMID:27803748

The respiratory care profession in Saudi Arabia: Past and present.

PubMed

Al-Otaibi, Hajed M; AlAhmari, Mohammed Dhafer

2016-01-01

The respiratory care (RC) profession in Saudi Arabia is over 40-year-old. Although there have been major advancements in the profession, no history and enough information are available about its development and evolvement at current. This paper describes the history and development of the field of RC and future prospects for the profession in Saudi Arabia. A comprehensive review and assessment were conducted through direct contact, interviews, and a review of existing documents in the Medical Services Division of the Ministry of Defense, the Ministry of Health, The Ministry of Civil Services, representative hospitals, academic institutions, and other relevant texts. The data obtained were evaluated for its relevance and grouped on a thematic basis. This is currently the first paper about the history and development of the RC profession in Saudi Arabia over the last 45 years.

Seasonal Surface Spectral Emissivity Derived from Terra MODIS Data

NASA Technical Reports Server (NTRS)

Sun-Mack, Sunny; Chen, Yan; Minnis, Patrick; Young, DavidF.; Smith, William J., Jr.

2004-01-01

The CERES (Clouds and the Earth's Radiant Energy System) Project is measuring broadband shortwave and longwave radiances and deriving cloud properties form various images to produce a combined global radiation and cloud property data set. In this paper, simultaneous data from Terra MODIS (Moderate Resolution Imaging Spectroradiometer) taken at 3.7, 8.5, 11.0, and 12.0 m are used to derive the skin temperature and the surface emissivities at the same wavelengths. The methodology uses separate measurements of clear sky temperature in each channel determined by scene classification during the daytime and at night. The relationships between the various channels at night are used during the day when solar reflectance affects the 3.7- m radiances. A set of simultaneous equations is then solved to derive the emissivities. Global monthly emissivity maps are derived from Terra MODIS data while numerical weather analyses provide soundings for correcting the observed radiances for atmospheric absorption. These maps are used by CERES and other cloud retrieval algorithms.

Mars-Gram Validation with Mars Global Surveyor Data

NASA Technical Reports Server (NTRS)

Justus, C. G.; Johnson, D.; Parker, Nelson C. (Technical Monitor)

2002-01-01

Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is an engineering-level Mars atmosphere model widely used for many b4ars mission applications. From 0-80 km, it is based on NASA Ames Mars General Circulation Model (MGCM), while above 80 km it is based on University of Arizona Mars Thermospheric General Circulation Model. Mars-GRAM 2001 and MGCM use surface topography from Mars Global Surveyor Mars Orbiting Laser Altimeter (MOLA). Validation studies are described comparing Mars-GRAM with Mars Global Surveyor Radio Science (RS) and Thermal Emission Spectrometer (TES) data. RS data from 2480 profiles were used, covering latitudes 75deg S to 72deg N, surface to approx. 40 km, for seasons ranging from areocentric longitude of Sun (Ls) = 70-160deg and 265-310deg. RS data spanned a range of local times, mostly 0-9 hours and 18-24 hours. For interests in aerocapture and precision landing, comparisons concentrated on atmospheric density. At a fixed height of 20 km, measured RS density varied by about a factor of 2.5 over the range of latitudes and Ls values observed. Evaluated at matching positions and times, average RS/Mars-GRAM density ratios were generally lf0.05, except at heights above approx. 25 km and latitudes above approx.50deg N. Average standard deviation of RS/Mars-GRAM density ratio was 6%. TES data were used covering surface to approx. 40 km, over more than a full Mars year (February, 1999 - June, 2001, just before start of Mars global dust storm). Depending on season, TES data covered latitudes 85deg S to 85deg N. Most TES data were concentrated near local times 2 hours and 14 hours. Observed average TES/Mars-GRAM density ratios were generally 1+/-0.05, except at high altitudes (15-30 km, depending on season) and high latitudes (> 45deg N), or at most altitudes in the southern hemisphere at Ls approx. 90 and 180deg). Compared to TES averages for a given latitude and season, TES data had average density standard deviation about the mean of approx. 6

4. VIEW NORTH, DETAIL SHOWING TERRA COTTA ROUND ARCH AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. VIEW NORTH, DETAIL SHOWING TERRA COTTA ROUND ARCH AND STRING COURSE AT FOURTH FLOOR LEVEL AND FRIEZE AT FIFTH FLOOR LEVEL - West Lexington Street, Number 308 (Commercial Building), 308 West Lexington Street, Baltimore, Independent City, MD

Strategies to address the nursing shortage in Saudi Arabia.

PubMed

Aboshaiqah, A

2016-09-01

To investigate the nursing shortage in Saudi Arabia and specifically the shortage of Saudi nurses in the healthcare workforce and to propose solutions. Literature published from 1993 to 2013 providing relevant information on the nursing shortage, cultural traditions and beliefs, and nursing education and policies in Saudi was accessed from multiple sources including Medline, CINAHL Plus and Google Scholar and from official Saudi government document and was reviewed. Saudi Arabia depends largely on an expatriate workforce, and this applies to nursing. Saudi Arabia is experiencing a nursing shortage in common with most countries in the world and a shortage of Saudi nationals, especially women, in the healthcare workforce. The world shortage of nursing is extrinsic to Saudi, but intrinsic factors include a poor image of the nursing profession in the country that is exacerbated by cultural factors. With the call for the Saudization of the workforce to replace the imported workforce by Saudi nationals, including nurses, through the 1992 Royal Decree, Saudi Arabia faces a problem in attracting and retaining Saudi nationals in the nursing workforce. Solutions are suggested that are aimed at improving the public image of nursing through education and the use of the media and improvements in the workplace by addressing working processes such as teamwork, ensuring adequate staffing levels and addressing some aspects of culture which may make working in nursing more compatible with being a Saudi national. © 2016 International Council of Nurses.

Primary centers and secondary concentrations of tectonic activity through time in the western hemisphere of Mars

USGS Publications Warehouse

Anderson, R.C.; Dohm, J.M.; Golombek, M.P.; Haldemann, A.F.C.; Franklin, B.J.; Tanaka, K.L.; Lias, J.; Peer, B.

2001-01-01

Five main stages of radial and concentric structures formed around Tharsis from the Noachian through the Amazonian as determined by geologic mapping of 24,452 structures within the stratigraphic framework of Mars and by testing their radial and concentric orientations. Tectonic activity peaked in the Noachian (stage 1) around the largest center, Claritas, an elongate center extending more than 20?? in latitude and defined by about half of the total grabens which are concentrated in the Syria Planum, Thaumasia, and Tempe Terra regions. During the Late Noachian and Early Hesperian (stage 2), extensional structures formed along the length of present-day Valles Marineris and in Thaumasia (with a secondary concentration near Warrego Vallis) radial to a region just to the south of the central margin of Valles Marineris. Early Hesperian (stage 3) radial grabens in Pavonis, Syria, Ulysses, and Tempe Terra and somewhat concentric wrinkle ridges in Lunae and Solis Plana and in Thaumasia, Sirenum, Memnonia, and Amazonis are centered northwest of Syria with secondary centers at Thaumasia, Tempe Terra, Ulysses Fossae, and western Valles Marineris. Late Hesperian/Early Amazonian (stage 4) structures around Alba Patera, the northeast trending alignment of Tharsis Montes, and Olympus Mons appears centered on Alba Patera. Stage 5 structures (Middle-Late Amazonian) represent the last pulse of Tharsis-related activity and are found around the large shield volcanoes and are centered near Pavonis Mons. Tectonic activity around Tharsis began in the Noachian and generally decreased through geologic time to the Amazonian. Statistically significant radial distributions of structures formed during each stage, centered at different locations within the higher elevations of Tharsis. Secondary centers of radial structures during many of the stages appear related to previously identified local magmatic centers that formed at different times and locations throughout Tharsis. Copyright 2001 by

Northern Arabia Etched Terrain

NASA Image and Video Library

2002-06-17

Many places on Mars, such as in this image from NASA Mars Odyssey spacecraft of a crater superposed on the floor of a larger crater, display scabby, eroded landscapes that commonly are referred to as etched terrain.

Constraints on crustal rheology and age of deformation from models of gravitational spreading in Ishtar Terra, Venus

NASA Astrophysics Data System (ADS)

Smrekar, Suzanne E.; Soloman, Sean C.

1992-12-01

Gravitational spreading is expected to lead to rapid relaxation of high relief due to the high surface temperature and associated weak crust on Venus. In this study, we use new Magellan radar and altimetry data to determine the extent of gravitational relaxation in Ishtar Terra, which contains the highest relief on Venus as well as areas of extremely high topographic slope. Within Ishtar Terra the only mountain belts found on Venus, Akna, Danu, Freyja, and Maxwell Montes, nearly encircle the smooth, high (3-4 km) plateau of Lakshmi Planum. Finite-element models of this process give expected timescales for relaxation of relief and failure at the surface. From these modeling results we attempt to constrain the strength of the crust and timescales of deformation in Ishtar Terra. Below we discuss observational evidence for gravitational spreading in Ishtar Terra, results from the finite-element modeling, independent age constraints, and implications for the rheology and timing of deformation.

Constraints on crustal rheology and age of deformation from models of gravitational spreading in Ishtar Terra, Venus

NASA Technical Reports Server (NTRS)

Smrekar, Suzanne E.; Soloman, Sean C.

1992-01-01

Gravitational spreading is expected to lead to rapid relaxation of high relief due to the high surface temperature and associated weak crust on Venus. In this study, we use new Magellan radar and altimetry data to determine the extent of gravitational relaxation in Ishtar Terra, which contains the highest relief on Venus as well as areas of extremely high topographic slope. Within Ishtar Terra the only mountain belts found on Venus, Akna, Danu, Freyja, and Maxwell Montes, nearly encircle the smooth, high (3-4 km) plateau of Lakshmi Planum. Finite-element models of this process give expected timescales for relaxation of relief and failure at the surface. From these modeling results we attempt to constrain the strength of the crust and timescales of deformation in Ishtar Terra. Below we discuss observational evidence for gravitational spreading in Ishtar Terra, results from the finite-element modeling, independent age constraints, and implications for the rheology and timing of deformation.

Divergent plate boundaries and crustal spreading on Venus: Evidence from Aphrodite Terra

NASA Technical Reports Server (NTRS)

Crumpler, L. S.; Head, James W.

1989-01-01

The modes of lithospheric heat transfer and the tectonic styles may differ between Earth and Venus, depending on how the high surface temperature (700 K = 430 C), dense and opaque atmosphere (approx. 10 MPa = 100 bars), lack of water oceans, and the other known ways in which Venus differs from Earth, influence basic lithospheric processes, thermal gradient, upper mantle temperature, thermal and chemical evolution, and convection. A fundamental question is whether the lithosphere of Venus is horizontally stable, like the other terrestrial planets, or is mobile like that on Earth. The variety of characteristics, their integrated relationships, and their predictable behavior throughout Western Aphrodite Terra are similar to those features known to occur in association with the terrestrial seafloor at spreading centers and divergent plate boundaries. It is concluded that Western Aphrodite Terra represents the site of crustal spreading centers and divergent plate boundaries. The extent of similar characteristics and processes elsewhere on Venus outside of the 13,000 km long Western and Eastern Aphrodite Terra rise is unknown at the present, but their presence in other areas of the equatorial highlands, suggested from recent analysis, may be tested with forthcoming Magellan data.

Global Color Views of Mars

NASA Technical Reports Server (NTRS)

1997-01-01

About 1000 Viking Orbiter red- and violet-filter images have been processed to provide global color coverage of Mars at a scale of 1 km/pixel. Individual image frames acquired during a single spacecraft revolution were first processed through radiometric calibration, cosmetic cleanup, geometric control, reprojection, and mosaicing. We have produced a total of 57 'single-rev' mosaics. All of the mosaics are geometrically tied to the Mars Digital Image Mosaic, a black-and-white base map with a scale of 231 m/pixel. We selected a subset of single-rev mosaics that provide the best global coverage (least atmospheric obscuration and seasonal frost); photometric normalization was applied to remove atmospheric effects and normalize the variations in illumination and viewing angles. Finally, these normalized mosaics were combined into global mosaics. Global coverage is about 98% complete in the red-filter mosaic and 95% complete in the violet-filter mosaic. Gaps were filled by interpolation. A green-filter image was synthesized from an average of the red and violet filter data to complete a 3-color set. The Viking Orbiters acquired actual green-filter images for only about half of the Martian surface. The final mosaic has been reprojected into several map projections. The orthographic view shown here is centered at 20 degrees latitude and 60 degrees longitude. The orthographic view is most like the view seen by a distant observer looking through a telescope. The color balance selected for these images was designed to be close to natural color for the bright reddish regions such as Tharsis and Arabia, but the data have been 'stretched' such that the relatively dark regions appear darker and less reddish that their natural appearance. This stretching allows us to better see the color and brightness variations on Mars, which are related to the composition or physical structure of the surface materials, which include volcanic lava flows, wind- and water-deposited sedimentary

Sleep Medicine in Saudi Arabia.

PubMed

Almeneessier, Aljohara S; BaHammam, Ahmed S

2017-04-15

The practice of sleep medicine in Saudi Arabia began in the mid to late 1990s. Since its establishment, this specialty has grown, and the number of specialists has increased. Based on the available data, sleep disorders are prevalent among the Saudi population, and the demand for sleep medicine services is expected to increase significantly. Currently, two training programs are providing structured training and certification in sleep medicine in this country. Recently, clear guidelines for accrediting sleep medicine specialists and technologists were approved. Nevertheless, numerous obstacles hamper the progress of this specialty, including the lack of trained technicians, specialists, and funding. Increasing the awareness of sleep disorders and their serious consequences among health care workers, health care authorities, and insurance companies is another challenge. Future plans should address the medical educational system at all levels to demonstrate the importance of early detection and the treatment of sleep disorders. This review discusses the current position of and barriers to sleep medicine practice and education in Saudi Arabia. © 2017 American Academy of Sleep Medicine

Measurement of Subsidence in the Yangbajain Geothermal Fields from TerraSAR-X

NASA Astrophysics Data System (ADS)

Li, Yongsheng; Zhang, Jingfa; Li, Zhenhong

2016-08-01

Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. Due to its high resolution and short repeat cycle, TerraSAR-X provides detailed surface deformation information at the Yangbajain geothermal fields.

Volcanism in Northwest Ishtar Terra, Venus

NASA Astrophysics Data System (ADS)

Gaddis, Lisa R.; Greeley, Ronald

1990-10-01

Evidence is presented for a previously undocumented volcanic complex in the highlands of NW Ishtar Terra (74 deg N, 313 deg E). The proposed valcanic center is in mountainous banded terrain thought to have been formed by regional compression. Data used include Soviet Venera 15/16 radar images and topography (Fotokarta Veneri B-4, 1987). An attempt is made to assess the place of this feature in the framework of known volcanic landforms of the Lakshmi Planum and to examine the relationships between volcanism and tectonism in this region.

Volcanism in Northwest Ishtar Terra, Venus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaddis, L.R.; Greeley, R.

Evidence is presented for a previously undocumented volcanic complex in the highlands of NW Ishtar Terra (74 deg N, 313 deg E). The proposed valcanic center is in mountainous banded terrain thought to have been formed by regional compression. Data used include Soviet Venera 15/16 radar images and topography (Fotokarta Veneri B-4, 1987). An attempt is made to assess the place of this feature in the framework of known volcanic landforms of the Lakshmi Planum and to examine the relationships between volcanism and tectonism in this region. 38 refs.

Leadership style and organisational commitment among nursing staff in Saudi Arabia.

PubMed

Al-Yami, Mansour; Galdas, Paul; Watson, Roger

2018-03-23

To examine how nurse managers' leadership styles, and nurses' organisational commitment in Saudi Arabia relate. Effective leadership is influential in staff retention; however, recruiting and maintaining nurses is an increasing problem in Saudi Arabia. Using a survey design, the Multifactor Leadership Questionnaire and the Organisational Commitment Questionnaire were distributed to a sample of 219 nurses and nurse managers from two hospitals in Saudi Arabia. Transformational leadership was the most dominant leadership style. After controlling for the influence of manager/staff status, nationality and hospitals, transformational leadership was the strongest contributor to organisational commitment. Perceptions of both transformational and transactional leadership styles, increased with age for nurse managers and nursing staff. Introducing the Full Range of Leadership model to the Saudi nursing workforce could help to prepare Saudi nurses for positions as nurse managers and leaders. The study provides insight into the type of leadership that is best suited to the dynamic and changing health care system in Saudi Arabia. It is possible that transformational leaders could influence and induce positive changes in nursing. © 2018 The Authors. Journal of Nursing Management Published by John Wiley & Sons Ltd.

eHealth in Saudi Arabia: Current Trends, Challenges and Recommendations.

PubMed

Alsulame, Khaled; Khalifa, Mohamed; Househ, Mowafa

2015-01-01

The purpose of this study is to explore the current status of eHealth in Saudi Arabia from the perspective of health informatics professionals. We used a case study approach and analyzed participant data using thematic analysis. The study took place between July and August 2013. Data collection included interviews with nine senior health information professionals in Saudi Arabia. The findings describe participant views on current eHealth trends in Saudi Arabia and show differences among Saudi healthcare organizations in terms of eHealth adoption. Participants also describe the challenges relating to organizational and cultural issues, end user attitudes towards eHealth projects, and the lack of specialized human resources to implement eHealth systems. Two main recommendations made by the participants were to form a new national body for eHealth and to develop a unified plan for the implementation of Saudi eHealth initiatives.

Adult Education in Saudi Arabia.

ERIC Educational Resources Information Center

Griffin, Tim D.; Algren, Mark S.

Religion pervades all aspects of Saudi Arabia, the conservative home of Islam, where the constitution is the Quran and law is interpreted by religious scholars. A formal adult basic education program was initiated in 1960. As part of the country's modernization since the early 1970s, the Saudi government has begun an enormous nation-building plan…

CRISM's Global Mapping of Mars, Part 3

NASA Technical Reports Server (NTRS)

2007-01-01

processed version of tile 750, showing a part of Mars called Tyrrhena Terra in the ancient, heavily cratered highlands. The colored strips are CRISM multispectral survey data acquired over several months, in which each pixel began as calibrated 72-color spectrum of Mars. An experimental correction for illumination and atmospheric effects was applied to the data, to show how Mars' surface would appear if each strip was imaged with the same illumination and without an atmosphere. Then, the spectrum for each pixel was transformed into a set of 'summary parameters,' which indicate absorptions showing the presence of different minerals. Detections of the igneous, iron-bearing minerals olivine and pyroxene are shown in the red and blue image planes, respectively. Clay-like minerals called phyllosilicates, which formed when liquid water altered the igneous rocks, are shown in the green image plane. The gray areas between the strips are from an earlier mosaic of the planet taken by the Thermal Emission Imaging System (THEMIS) instrument on Mars Odyssey, and are included for context. Note that most areas imaged by CRISM contain pyroxene, and that olivine-containing rocks are concentrated on smooth deposits that fill some crater floors and the low areas between craters. Phyllosilicate-containing rocks are concentrated in and around small craters, such as the one at 13 degrees south latitude, 97 degrees east longitude. Their concentration in crater materials suggests that they were excavated when the craters formed, from a layer that was buried by the younger, less altered, olivine- and pyroxene-containing rocks.

CRISM is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in

Preliminary GRS Measurement of Chlorine Distribution on Surface of Mars

NASA Astrophysics Data System (ADS)

Keller, J. M.; Boynton, W. V.; Taylor, G. J.; Hamara, D.; Janes, D. M.; Kerry, K.

2003-12-01

Ongoing measurements with the Gamma Ray Spectrometer (GRS) aboard Mars Odyssey provide preliminary detection of chlorine at the surface of Mars. Summing all data since boom deployment and using a forward calculation model, we estimate values for chlorine concentration at 5° resolution. Rebinning this data and smoothing with a 15-degree-radius boxcar filter reveal regions of noticeable chlorine enrichment at scales larger than the original 5° resolution and allow for preliminary comparison with previous Mars datasets. Analyzing chlorine concentrations within 30 degrees of the equator, we find a negative correlation with thermal inertia (R2=0.55) and positive correlation with albedo (R2=0.52), indicating that chlorine is associated with fine, non-rock surface materials. Although possibly a smoothing artifact, the spatial correlation is more noticeable in the region covering Tharsis and Amazonis than around Arabia and Elysium. Additionally, a noticeable region of chlorine enrichment appears west of Tharsis Montes ( ˜0 to 20N, ˜110 to 150W) and chlorine concentration is estimated to vary in the equatorial region by over a factor of two. A simplified two-component model involving chlorine-poor rocks and a homogenous chlorine-rich fine material requires rock abundance to vary from zero to over 50%, a result inconsistent with previous measurements and models. In addition to variations in rock composition and distribution, substantial variations in chlorine content of various types of fine materials including dust, sand, and duricrust appear important in explaining this preliminary observation. Surprisingly, visual comparison of surface units mapped by Christensen and Moore (1992) does not show enrichment in chlorine associated with regions of indurated surfaces, where cementation has been proposed. Rather, Tharsis, a region of active deposition with proposed mantling of 0.1 to 2 meters of recent dust (Christensen 1986), shows the greatest chlorine signal. In light of

Simulations with COSMO-CLM over Turin including TERRA-URB parameterization

NASA Astrophysics Data System (ADS)

Bucchignani, Edoardo; Mercogliano, Paola; Milelli, Massimo; Raffa, Mario

2017-04-01

The increase of built surfaces constitutes the main reason for the formation of Urban Heat Islands (UHIs), since urban canyons block the release of the reflected radiation. The main contribution to the formation of UHIs is the missing night-cooling of horizontal surfaces, together with cloudless sky and light winds. Of course, there is also a contribution from indoor heating, vehicles presence, and waste heat from air conditioning and refrigeration systems. The COSMO-CLM model, even at high resolution, is currently not able to cope with this effect. Nevertheless, the increase of applications in which a high number of grid points is located over urban areas, requires that COSMO-CLM becomes able to take into account also urban climate features. In fact, they are crucial for better forecast of temperature and for a better characterization of the local patterns of several atmospherical variables (wind, surface fluxes). Recently TERRA-URB, a bulk parameterisation scheme with a prescribed anthropogenic heat flux, has been incorporated into COSMO-CLM for the standard land-surface module TERRA-ML. It offers an intrinsic representation of the urban physics with modifications of input data, soil module and land atmospheric interactions. In the first half of July 2015, Piemonte region and Turin in particular experienced extreme temperature values and uncomfortable conditions for the population. In Turin, the maximum temperature since 1990 (38.5°) has been recorded in July 2015. Ground stations data highlighted the presence of a UHI effect over Turin. This is the reason why this area and this period represent a suitable benchmark to test the capabilities of COSMO-CLM, and in particular of the urban parameterization. The computational domain considered is centered over Turin, discretized with 100 x 100 grid-points, employing a spatial resolution of 0.009° (about 1 km). The ECMWF IFS analysis at 0.075° have been used as forcing data. Two simulations have been performed over

Assessment of the Collection 6 Terra and Aqua MODIS bands 1 and 2 calibration performance

NASA Astrophysics Data System (ADS)

Wu, A.; Chen, X.; Angal, A.; Li, Y.; Xiong, X.

2015-09-01

MODIS (Moderate Resolution Imaging Spectroradiometer) is a key sensor aboard the Terra (EOS AM) and Aqua (EOS PM) satellites. MODIS collects data in 36 spectral bands and generates over 40 data products for land, atmosphere, cryosphere and oceans. MODIS bands 1 and 2 have nadir spatial resolution of 250 m, compared with 500 m for bands 3 to 7 and 1000 m for all the remaining bands, and their measurements are crucial to derive key land surface products. This study evaluates the calibration performance of the Collection-6 L1B for both Terra and Aqua MODIS bands 1 and 2 using three vicarious approaches. The first and second approaches focus on stability assessment using data collected from two pseudo-invariant sites, Libya 4 desert and Antarctic Dome C snow surface. The third approach examines the relative stability between Terra and Aqua in reference to a third sensor from a series of NOAA 15-19 Advanced Very High Resolution Radiometer (AVHRR). The comparison is based on measurements from MODIS and AVHRR Simultaneous Nadir Overpasses (SNO) over a thirteen-year period from 2002 to 2015. Results from this study provide a quantitative assessment of Terra and Aqua MODIS bands 1 and 2 calibration stability and the relative calibration differences between the two sensors.

Wadi Habawnah, Saudi Arabia

NASA Technical Reports Server (NTRS)

1985-01-01

These unique weathered volcanic intrusions near Wadi Habawnah, Saudi Arabia (18.0N, 44.0E) are located near Najran, north of the Yemen border. This harsh and rugged desert landscape has been heavily wind eroded and, to a lesser extent, water eroded, as evidenced by the dendritic patterns in this region where rainfall is a seldom occurance. Only a dwindling number of nomadic tribes inhabit this harsh region of few resources.

Radiometric cross-calibration of EO-1 ALI with L7 ETM+ and Terra MODIS sensors using near-simultaneous desert observations

USGS Publications Warehouse

Chander, Gyanesh; Angal, Amit; Choi, Taeyoung; Xiong, Xiaoxiong

2013-01-01

The Earth Observing-1 (EO-1) satellite was launched on November 21, 2000, as part of a one-year technology demonstration mission. The mission was extended because of the value it continued to add to the scientific community. EO-1 has now been operational for more than a decade, providing both multispectral and hyperspectral measurements. As part of the EO-1 mission, the Advanced Land Imager (ALI) sensor demonstrates a potential technological direction for the next generation of Landsat sensors. To evaluate the ALI sensor capabilities as a precursor to the Operational Land Imager (OLI) onboard the Landsat Data Continuity Mission (LDCM, or Landsat 8 after launch), its measured top-of-atmosphere (TOA) reflectances were compared to the well-calibrated Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) and the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensors in the reflective solar bands (RSB). These three satellites operate in a near-polar, sun-synchronous orbit 705 km above the Earth's surface. EO-1 was designed to fly one minute behind L7 and approximately 30 minutes in front of Terra. In this configuration, all the three sensors can view near-identical ground targets with similar atmospheric, solar, and viewing conditions. However, because of the differences in the relative spectral response (RSR), the measured physical quantities can be significantly different while observing the same target. The cross-calibration of ALI with ETM+ and MODIS was performed using near-simultaneous surface observations based on image statistics from areas observed by these sensors over four desert sites (Libya 4, Mauritania 2, Arabia 1, and Sudan 1). The differences in the measured TOA reflectances due to RSR mismatches were compensated by using a spectral band adjustment factor (SBAF), which takes into account the spectral profile of the target and the RSR of each sensor. For this study, the spectral profile of the target comes from the near-simultaneous EO-1

Measuring Mars' Atmospheric Neutral Density from 160 to 220km with the MGS Electron Reflectometer

NASA Astrophysics Data System (ADS)

Lillis, R.; Engel, J.; Mitchell, D.; Brain, D.; Lin, R.; Bougher, S.; Acuna, M.

2005-08-01

The Magnetometer/Electron Reflectometer (MAG/ER) experiment aboard Mars Global Surveyor (MGS) samples the local electron population's distribution in energy and pitch angle (angle between electron velocity and local magnetic field direction) at the mapping orbit altitude of ˜400km. We develop a single-particle model of the electrons' interaction with the neutral atmosphere and motion along open field-lines connecting the solar wind to remnant crustal magnetization. Electron reflection from magnetic gradients and absorption due to inelastic collisons with atmospheric neutrals results in characteristic pitch angle (PA) distributions for open field lines. By assuming the validity of spherical harmonic expansions (Cain et al, 2003) in the strongest field regions of Mars (such as Terra Sirenum), we trace the electron paths and fit these PA distributions to our model to constrain the scale height and density of the neutral atmosphere in the region of greatest absorption, 160-220km. We analyse almost 3 martian years of MGS mapping Orbit Data and present the first measurements of Mars' neutral density above 180km. Although the uncertainties in single measurements are quite large, averaging over many measurements over a period of weeks allows us to see long-term trends. Major results are: 1) a mean density of 0.03 kg/km3 at 160km with a month-averaged variation of ˜40%, 2) a very strong annual seasonal variation, confirmed by periodogram and least-squares fit and 3) increasing seasonal density variability with distance from the equator. We see broad general agreement with predictions from Mars Thermosphere Global Circulation Model (MTGCM) simulations [Bougher et al, 2004] and with inferred densities from MGS Doppler tracking data [Tracadas et al, 2001]. Our results will help to constrain the upper boundaries of GCMs and assist orbital decay calculations for low-orbiting spacecraft, such as the 2005 Mars Reconnaissance Orbiter. We thank the NASA Jet Propulsion Laboratory

75 FR 5780 - Green Borders Geothermal, LLC, Complainant, v. Terra-Gen Dixie Valley, LLC, Respondent; Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-04

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL10-36-000] Green Borders Geothermal, LLC, Complainant, v. Terra-Gen Dixie Valley, LLC, Respondent; Notice of Complaint January 28, 2010. Take notice that on January 25, 2010, Green Borders Geothermal, LLC (Green Borders) filed a formal complaint against Terra-Gen Dixie Valle...

Saudi Arabia’s Counterterrorism Methods: A Case Study on Homeland Security

DTIC Science & Technology

2017-06-01

laws to safeguard the homeland and its borders, Saudi Arabia has enacted laws that impose stiff penalties aimed at money laundering and other illicit...safeguard the homeland and its borders, Saudi Arabia has enacted laws that impose stiff penalties aimed at money laundering and other illicit activities...34 1. Combating Financing Terrorist Organizations ............... 34 2. Combating Money Laundering by

The need for national medical licensing examination in Saudi Arabia

PubMed Central

Bajammal, Sohail; Zaini, Rania; Abuznadah, Wesam; Al-Rukban, Mohammad; Aly, Syed Moyn; Boker, Abdulaziz; Al-Zalabani, Abdulmohsen; Al-Omran, Mohammad; Al-Habib, Amro; Al-Sheikh, Mona; Al-Sultan, Mohammad; Fida, Nadia; Alzahrani, Khalid; Hamad, Bashir; Al Shehri, Mohammad; Abdulrahman, Khalid Bin; Al-Damegh, Saleh; Al-Nozha, Mansour M; Donnon, Tyrone

2008-01-01

Background Medical education in Saudi Arabia is facing multiple challenges, including the rapid increase in the number of medical schools over a short period of time, the influx of foreign medical graduates to work in Saudi Arabia, the award of scholarships to hundreds of students to study medicine in various countries, and the absence of published national guidelines for minimal acceptable competencies of a medical graduate. Discussion We are arguing for the need for a Saudi national medical licensing examination that consists of two parts: Part I (Written) which tests the basic science and clinical knowledge and Part II (Objective Structured Clinical Examination) which tests the clinical skills and attitudes. We propose this examination to be mandated as a licensure requirement for practicing medicine in Saudi Arabia. Conclusion The driving and hindering forces as well as the strengths and weaknesses of implementing the licensing examination are discussed in details in this debate. PMID:19032779

Emergence of new virulent rabbit hemorrhagic disease virus strains in Saudi Arabia.

PubMed

Ismail, Mahmoud M; Mohamed, Mahmoud H A; El-Sabagh, Ibrahim M; Al-Hammadi, Mohamed A

2017-02-01

Rabbit hemorrhagic disease is an acute fatal highly contagious viral infectious disease that causes high losses among rabbitries. The disease was first reported in China in 1984 and later on in Saudi Arabia in 1996. The aim of this study was to investigate the emergence and pathogenicity of new rabbit hemorrhagic disease virus (RHDV) strains in Saudi Arabia. The pathogenicity was confirmed by inoculation in susceptible rabbits. Three RHDV strains were detected by reverse transcriptase polymerase chain reaction (RT-PCR) using primers targeting VP60 capsid protein gene in infected rabbitries during 2012 and 2013. These strains clustered into two genetically distinct genogroups related to year of isolation (G2 and G3). All new Saudi Arabia viruses clustered with the European strains, while the old strains clustered with strains from China and America. Based on amino acids and nucleotide sequences, the Saudi Arabia strains (RHD/1/SA/2012, RHD/2/SA/2012, and RHD/3/SA /2013) had high identity with Mexico89, Ca11-ITA, and 00-13,FRA virus; on the other hand, there was a relatively high identity with Bahrain strain. The evolutionary relationship of Saudi RHDVs strains revealed significant nucleotides and amino acid substitutions in hypervariable region E, suggesting the emergence of new RHDVs circulating in Saudi Arabia rabbitries. These antigenic changes represented by the antigenic index might be a potential cause of vaccination failure and raises the need to review the vaccination strategies against RHD.

Comprehensive view of the population history of Arabia as inferred by mtDNA variation.

PubMed

Černý, Viktor; Čížková, Martina; Poloni, Estella S; Al-Meeri, Ali; Mulligan, Connie J

2016-04-01

Genetic and archaeological research supports the theory that Arabia was the first region traversed by modern humans as they left Africa and dispersed throughout Eurasia. However, the role of Arabia from the initial migration out of Africa until more recent times is still unclear. We have generated 379 new hypervariable segment 1 (HVS-1) sequences from a range of geographic locations throughout Yemen. We compare these data to published HVS-1 sequences representing Arabia and neighboring regions to build a unique dataset of 186 populations and 14,290 sequences. We identify 4,563 haplotypes unevenly distributed across Arabia and neighboring regions. Arabia contains higher proportions of shared haplotypes than the regions with which it shares these haplotypes, suggesting high levels of migration through the region. Populations in Arabia show higher levels of population expansion than those in East Africa, but lower levels than the Near East, Middle East or India. Arabian populations also show very high levels of genetic variation that overlaps with variation from most other regions. We take a population genetics approach to provide a comprehensive view of the relationships of Arabian and neighboring populations. We show that Arabian populations share closest links to the Near East and North Africa, but have a more ancient origin with slower demographic growth and/or lower migration rates. Our conclusions are supported by phylogenetic studies but also suggest that recent migrations have erased signals of earlier events. © 2015 Wiley Periodicals, Inc.

Magnetically inferred basement structure in central Saudi Arabia

USGS Publications Warehouse

Johnson, P.R.; Stewart, I.C.F.

1995-01-01

A compilation of magnetic data acquired during the past three decades for a region in central Saudi Arabia where Precambrian basement is partly exposed on the Arabian shield and partly concealed by overlying Phanerozoic strata, shows a central sector of conspicuous N-S-trending anomalies, a heterogeneous western sector of short-wavelength, high-intensity anomalies, and an eastern sector of low- to moderate-intensity broad-wavelength anomalies. Anomalies in the western and central sectors correlate with Neoproterozoic metavolcanic, metasedimentary, and intrusive rocks of the Arabian shield and are interpreted as delineating extensions of shield-type rocks down-dip beneath Phanerozoic cover. These rocks constitute terranes making up part of a Neoproterozoic orogenic belt that underlies Northeast Africa and western Arabia and it is proposed that their magnetically indicated easternmost extent marks the concealed eastern edge of the orogenic belt in central Arabia. The flat magnetic signature of the eastern sector, not entirely accounted for as an effect of deep burial, may reflect the presence of a crustal block different in character to the terranes of the orogenic belt and, speculatively, may outline a continental block that, according to some tectonic models of the region, collided with the Neoproterozoic terranes and thereby caused their deformation and tectonic accretion.

Four Views of Mars in Northern Summer

NASA Technical Reports Server (NTRS)

1997-01-01

Four faces of Mars as seen on March 30, 1997 are presented in this montage of NASA Hubble Space Telescope images. Proceeding in the order upper-left, upper-right, lower-left, lower-right, Mars has rotated about ninety degrees between each successive time step. For example the Tharsis volcanoes, which are seen (between 7:30 and 9 o'clock positions) in mid-morning in the UPPER-RIGHT view, are seen near the late afternoon edge of the planet (about 3 o'clock position) in the lower-left image. All of these color images are composed of individual red (673 nanometers), green (502 nm), and blue (410 nm) Planetary Camera exposures.

Upper left: This view is centered on Ares Valles, where Pathfinder will land on July 4, 1997; the Valles Marineris canyon system stretches to the west across the lower left portion of the planet, while the bright, orangish desert of Arabia Planitia is to the east. The bright polar water-ice cap, surrounded by a dark ring of sand dunes, is obvious in the north; since it is northern summer and the pole is tilted toward us, the residual north polar cap is seen in its entirety in all four images. Acidalia Planitia, the prominent dark area fanning southward from the polar region, is thought to have a surface covered with dark sand. Numerous 'dark wind streaks' are visible to the south of Acidalia, resulting from wind-blown sand streaming out of the interiors of craters.

Upper right: The Tharsis volcanos and associated clouds are prominent in the western half of this view. Olympus Mons, spanning 340 miles (550 km) across its base and reaching an elevation of 16 miles (25 km), extends through the cloud deck near the western limb, while (from the south) Arsia Mons, Pavonis Mons, and Ascraeus Mons are to the west of center. Valles Marineris stretches to the east, and the Pathfinder landing site is shrouded in clouds near the afternoon limb.

Lower left: This relatively featureless sector of Mars stretches from the Elysium volcanic region in the

An Overview of Mars Vicinity Transportation Concepts for a Human Mars Mission

NASA Technical Reports Server (NTRS)

Dexter, Carol E.; Kos, Larry

1998-01-01

To send a piloted mission to Mars, transportation systems must be developed for the Earth to Orbit, trans Mars injection (TMI), capture into Mars orbit, Mars descent, surface stay, Mars ascent, trans Earth injection (TEI), and Earth return phases. This paper presents a brief overview of the transportation systems for the Human Mars Mission (HMM) only in the vicinity of Mars. This includes: capture into Mars orbit, Mars descent, surface stay, and Mars ascent. Development of feasible mission scenarios now is important for identification of critical technology areas that must be developed to support future human missions. Although there is no funded human Mars mission today, architecture studies are focusing on missions traveling to Mars between 2011 and the early 2020's.

15 Years of Terra, 14 Years of Application Usage

NASA Astrophysics Data System (ADS)

Schmaltz, J. E.; Alarcon, C.; Boller, R. A.; Cechini, M. F.; Davies, D.; Fu, G.; Gunnoe, T.; Hall, J. R.; Huang, T.; Ilavajhala, S.; Jackson, M.; King, J.; McGann, M.; Murphy, K. J.; Roberts, J. T.; Thompson, C. K.; Ye, G.

2014-12-01

The instruments onboard the Terra spacecraft were designed for long-term Earth science research but not long after launch it became apparent that this data and imagery could be made available in near real-time for applications users. During the year 2000 fire season in the western United States, the US Forest Service approached NASA with a request to expedite MODIS fire detections. The Rapid Response system was created to generate fire detections as well as true color imagery in both swath and geo-referenced formats. This imagery was used by a wide variety of applications, such as NASA's AERONET program, the USDA Foreign Agricultural Service, Antarctic resupply shipping, flood mapping for relief agencies, Deepwater Horizon monitoring, volcanic ash monitoring, as well as print, televised, and Internet media. From 2004, the University of Maryland's Web Fire Mapper helped distribute fire detection information in a variety of formats. However, the applications community expressed the need for near-real time access to the underlying data. This requirement led to the development of the Land Atmosphere Near real-time Capability for EOS (Earth Observing System) (LANCE) in 2009. To achieve the latency requirements, many components of the EOS satellite operations, ground and science processing systems had to be made more efficient. In addition, products that require ancillary data were modified to use alternate inputs. Forty Terra MODIS data products are currently available from LANCE. LANCE also includes data from other instruments including AIRS, AMSR-E, MLS, and OMI. To help near-real time users navigate this large data offering, a new imagery service was begun in 2011 - Global Imagery Browse Services (GIBS). This service provides very responsive viewing using the Web Map Tile Service protocol. These programs will continue to support and expand the use of Terra data for near-real time applications well into the future.

Terra Vac In Situ Vacuum Extraction System: Applications Analysis Report

EPA Science Inventory

This document is an evaluation of the Terra Vac in situ vacuum extraction system and its applicability as a treatment method for waste site cleanup. This report analyzes the results from the Superfund Innovative Technology Evaluation (SITE) Program’s 56-day demonstration at t...

Decadal Variation of Precipitation in Saudi Arabia induced by Agricultural Irrigation

NASA Astrophysics Data System (ADS)

Lo, M. H.; Wey, H. W.; Wada, Y.; IM, E. S.; Chien, R. Y.; Wu, R. J.

2017-12-01

Decadal variation of wet-season precipitation has been found in the arid region of central Saudi Arabia. 1980s has been a rather wet decade compared with the decades before. Previous studies have mentioned that the irrigation moisture may contribute to the precipitation anomalies in Saudi Arabia. In the current study, we show from observational data that the contribution of the variation comes mostly from February to May. As the irrigation is a localized forcing, we therefore use the Weather Research and Forecasting (WRF) Model to simulate the response of the land-atmosphere interaction to the wet soil moisture resulted from additional irrigation moisture supply. Preliminary result shows in the irrigated simulation that precipitation in central Saudi Arabia is enhanced, indicating the possible link between irrigation expansion in the 1980s and the decadal precipitation variation over central Saudi Arabia. We propose it is the anomalous convergence induced by irrigation as well as additional moisture that contribute to the enhanced precipitation over heavily irrigation region in the central Saudi Arabian. In addition, analysis on the daily precipitation from the WRF outputs indicates that positive rainfall anomalies tend to happen when there is rainfall originally; that is, irrigation enhances rainfall but not creates rainfall.

Mars

NASA Astrophysics Data System (ADS)

McSween, H. Y., Jr.

2003-12-01

More than any other planet, Mars has captured our attention and fueled our speculations. Much of this interest relates to the possibility of martian life, as championed by Percival Lowell in the last century and subsequently in scientific papers and science fiction. Lowell's argument for life on Mars was based partly on geochemistry, in that his assessmentof the planet's hospitable climate was dependent on the identification of H2O ice rather than frozen CO2 in the polar caps. Although this reasoning was refuted by Alfred Wallace in 1907, widespread belief in extant martian life persisted within the scientific community until the mid-twentieth century (Zahnle, 2001). In 1965 the Mariner 4 spacecraft flyby suddenly chilled this climate, by demonstrating that the martian atmosphere was thin and the surface was a cratered moonscape devoid of canals. This view of Mars was overturned again in 1971, when the Mariner 9 spacecraft discovered towering volcanoes and dry riverbeds, implying a complex geologic history. The first geochemical measurements on Mars, made by two Viking landers in 1976, revealed soils enriched in salts suggesting exposure to water, but lacking organic compounds which virtually ended discussion of martian life.The suggestion that a small group of achondritic meteorites were martian samples (McSween and Stolper, 1979; Walker et al., 1979; Wasson and Wetherill, 1979) found widespread acceptance when trapped gases in them were demonstrated to be compositionally similar to the Mars atmosphere ( Bogard and Johnson, 1983; Becker and Pepin, 1984). The ability to perform laboratory measurements of elements and isotopes present in trace quantities in meteorites has invigorated the subject of martian geochemistry. Indeed, because of these samples, we now know more about the geochemistry of Mars than of any other planet beyond the Earth-Moon system. Some studies of martian meteorites have prompted a renewed search for extraterrestrial life using chemical

Mars integrated transportation system multistage Mars mission

NASA Technical Reports Server (NTRS)

1991-01-01

In accordance with the objective of the Mars Integrated Transport System (MITS) program, the Multistage Mars Mission (MSMM) design team developed a profile for a manned mission to Mars. The purpose of the multistage mission is to send a crew of five astronauts to the martian surface by the year 2019. The mission continues man's eternal quest for exploration of new frontiers. This mission has a scheduled duration of 426 days that includes experimentation en route as well as surface exploration and experimentation. The MSMM is also designed as a foundation for a continuing program leading to the colonization of the planet Mars.

Flood routing of the Maja outflow across Xanthe Terra

NASA Technical Reports Server (NTRS)

Dehon, R. A.

1991-01-01

The object is to trace a single flood crest through the Maja outflow system and to evaluate the effects of topography on ponding and multiple channel routing. Maja Valles provides a good model because it has a single source and a well defined channel system. The 1500 km long Maja Valles originates in Juventae Chasma. The outflow system stretches 1100 km northward along the Lunae Planum/Xanthe Terra boundary, then eastward across the Xanthe Terra highlands. It descends to Chryse Planitia where it extends northeastward toward the middle of the basin. It is concluded that flood routing through multiple channels and retardation in local impoundments are responsible for breakup of the initial flood crest and the formation of multiple flood crests. Recombined flow near the mouths of these canyons results in an extended flow regime and multiple flood surges. As a result of ponding along the flood course, depositional sites are localized and renewed erosion downstream (from ponded sites) results in sediment source areas not greatly removed from depositional sites.

Irrigated Agriculture, Saudi Arabia

NASA Technical Reports Server (NTRS)

1990-01-01

In Saudi Arabia, center-pivot, swing-arm irrigated agriculture complexes such as the one imaged at Jabal Tuwayq (20.5N, 45.0 E) extract deep fossil water reserves to achieve food crop production self sufficiency in this desert environment. The significance of the Saudi expanded irrigated agriculture is that the depletion of this finite water resource is a short term solution to a long term need that will still exist when the water has been extracted.

Irrigated Agriculture, Saudi Arabia

NASA Image and Video Library

1990-01-20

In Saudi Arabia, center-pivot, swing-arm irrigated agriculture complexes such as the one imaged at Jabal Tuwayq (20.5N, 45.0 E) extract deep fossil water reserves to achieve food crop production self sufficiency in this desert environment. The significance of the Saudi expanded irrigated agriculture is that the depletion of this finite water resource is a short term solution to a long term need that will still exist when the water has been extracted.

Saudi Arabia Today. A Teaching Program on the Kingdom of Saudi Arabia: (1) Grades 1-3, Our Visit to Saudi Arabia; (2) Grades 4-6, A Modern Kingdom; (3) Junior High School, The Kingdom of Saudi Arabia; (4) Senior High School, The Kingdom of Saudi Arabia.

ERIC Educational Resources Information Center

Learning Enrichment, Inc., Williamsburg, VA.

This package includes materials for students and accompanying teaching guides and posters for teaching about life in contemporary Saudi Arabia for grades 1-8. The student folder for grades 1-3 presents information about the Middle Eastern nation in the form of a boy's letter to a friend back home. In the letter are descriptions of the cities of…

Mars Aerocapture and Validation of Mars-GRAM with TES Data

NASA Technical Reports Server (NTRS)

Justus, C. G.; Duvall, Aleta; Keller, Vernon W.

2005-01-01

Mars Global Reference Atmospheric Model (Mars-GRAM) is a widely-used engineering- level Mars atmospheric model. Applications include systems design, performance analysis, and operations planning for aerobraking, entry descent and landing, and aerocapture. Typical Mars aerocapture periapsis altitudes (for systems with rigid-aeroshell heat shields) are about 50 km. This altitude is above the 0-40 km height range covered by Mars Global Surveyor Thermal Emission Spectrometer (TES) nadir observations. Recently, TES limb sounding data have been made available, spanning more than two Mars years (more than 200,000 data profiles) with altitude coverage up to about 60 km, well within the height range of interest for aerocapture. Results are presented comparing Mars-GRAM atmospheric density with densities from TES nadir and limb sounding observations. A new Mars-GRAM feature is described which allows individual TES nadir or limb profiles to be extracted from the large TES databases, and to be used as an optional replacement for standard Mars-GRAM background (climatology) conditions. For Monte-Carlo applications such as aerocapture guidance and control studies, Mars-GRAM perturbations are available using these TES profile background conditions.

Perinatal Morbidity and Mortality in Offsprings of Diabetic Mothers in Qatif, Saudi Arabia.

ERIC Educational Resources Information Center

Al-Dabbous, Ibrahim A. Al-; And Others

1995-01-01

Studied perinatal and neonatal morbidity and mortality of diabetic mothers and their offspring in Qatif, Saudi Arabia. Suggests diabetes mellitus in pregnancy may be a common problem in Saudi Arabia, as poor maternal diabetic control results in high perinatal morbidity and mortality. Results suggest that health education and improved coverage of…

Cost containment: the Middle East. Saudi Arabia.

PubMed

Chang, R W

1994-08-01

The 1970s and early 1980s saw the phenomenal growth and development of healthcare services in Saudi Arabia. This growth was unique in that it took place in a country that lacked basic infrastructure and trained personnel, but had recently acquired great wealth. Developments that took hundreds of years to occur in other countries took only 20 yrs to attain in Saudi Arabia. This growth posed unique challenges and required novel solutions. Recently, the country has had to cope with a drastic decrease in oil revenue, as well as cutbacks in healthcare funding. Now that the basic foundations of a national healthcare service have been constructed, it remains to be seen whether gains can be consolidated and steady progress made as more and more Saudi nationals take over and run their own public and private healthcare services.

Lactase persistence variants in Arabia and in the African Arabs.

PubMed

Priehodová, Edita; Abdelsawy, Abdelhay; Heyer, Evelyne; Cerný, Viktor

2014-01-01

Lactase persistence (LP), the state enabling the digestion of milk sugar in adulthood, occurs only in some human populations. The convergent and independent origin of this physiological ability in Europe and Africa is linked with animal domestication that either had started in both places independently or had spread from the Near East by acculturation. However, it has recently been shown that at least in its southern parts, the population of Arabia not only has a different LP-associated mutation profile than the rest of Africa and Europe but also had experienced an independent demographic expansion occurring before the Neolithic around the Pleistocene-Holocene boundary. In Arabia, LP is associated with mutation -13,915*G and not, as in Europe, with -13,910*T or, as in Africa, with -13,907*G and -14,010*C. We show here that, in Arabia, -13,915*G frequency conforms to a partial clinal pattern and that this specific mutation has likely been spread from Arabia to Africa only recently from the sixth century AD onward by nomadic Arabs (Bedouins) looking for new pastures. Arabic populations in Africa that still maintain a nomadic way of life also have more -13,915*G variants and fewer sub-Saharan L-type mitochondrial DNA haplogroups; this observation matches archaeological and historical records suggesting that the migration of Arabic pastoralists was accompanied by gradual sedentarization that allowed for admixture with the local African population. Copyright © 2014 Wayne State University Press, Detroit, Michigan 48201-1309.

Cenozoic volcanic rocks of Saudi Arabia

USGS Publications Warehouse

Coleman, R.G.; Gregory, R.T.; Brown, G.F.

2016-01-01

The historical record of volcanic activity in Saudi Arabia suggests that volcanism is dormant. The harrats should be evaluated for their potential as volcanic hazards and as sources of geothermal energy. The volcanic rocks are natural traps for groundwater; thus water resources for agriculture may be significant and should be investigated.

Geologic Map of MTM 35337, 40337, and 45337 Quadrangles, Deuteronilus Mensae Region of Mars

USGS Publications Warehouse

Chuang, Frank C.; Crown, David A.

2009-01-01

Deuteronilus Mensae, first defined as an albedo feature at lat 35.0 deg N., long 5.0 deg E., by U.S. Geological Survey (USGS) and International Astronomical Union (IAU) nomenclature, is a gradational zone along the dichotomy boundary in the northern mid-latitudes of Mars. The boundary in this location includes the transition from the rugged cratered highlands of Arabia Terra to the northern lowland plains of Acidalia Planitia. Within Deuteronilus Mensae, polygonal mesas are prominent along with features diagnostic of Martian fretted terrain, including lobate debris aprons, lineated valley fill, and concentric crater fill. Lobate debris aprons, as well as the valley and crater fill deposits, are geomorphic indicators of ground ice, and their concentration in Deuteronilus Mensae is of great interest because of their potential association with Martian climate change. The paucity of impact craters on the surfaces of debris aprons and the presence of ice-cemented mantle material imply young (for example, Amazonian) surface ages that are consistent with recent climate change in this region of Mars. North of Deuteronilus Mensae are the northern lowlands, a potential depositional sink that may have had large standing bodies of water or an ocean in the past. The northern lowlands have elevations that are several kilometers below the ancient cratered highlands with significantly younger surface ages. The morphologic and topographic characteristics of the Deuteronilus Mensae region record a diverse geologic history, including significant modification of the ancient highland plateau and resurfacing of low-lying regions. Previous studies of this region have interpreted a complex array of geologic processes, including eolian, fluvial and glacial activity, coastal erosion, marine deposition, mass wasting, tectonic faulting, effusive volcanism, and hydrovolcanism. The origin and age of the Martian crustal dichotomy boundary are fundamental questions that remain unresolved at the

Complete genome sequencing and phylogenetic analysis of dengue type 1 virus isolated from Jeddah, Saudi Arabia.

PubMed

Azhar, Esam I; Hashem, Anwar M; El-Kafrawy, Sherif A; Abol-Ela, Said; Abd-Alla, Adly M M; Sohrab, Sayed Sartaj; Farraj, Suha A; Othman, Norah A; Ben-Helaby, Huda G; Ashshi, Ahmed; Madani, Tariq A; Jamjoom, Ghazi

2015-01-16

Dengue viruses (DENVs) are mosquito-borne viruses which can cause disease ranging from mild fever to severe dengue infection. These viruses are endemic in several tropical and subtropical regions. Multiple outbreaks of DENV serotypes 1, 2 and 3 (DENV-1, DENV-2 and DENV-3) have been reported from the western region in Saudi Arabia since 1994. Strains from at least two genotypes of DENV-1 (Asia and America/Africa genotypes) have been circulating in western Saudi Arabia until 2006. However, all previous studies reported from Saudi Arabia were based on partial sequencing data of the envelope (E) gene without any reports of full genome sequences for any DENV serotypes circulating in Saudi Arabia. Here, we report the isolation and the first complete genome sequence of a DENV-1 strain (DENV-1-Jeddah-1-2011) isolated from a patient from Jeddah, Saudi Arabia in 2011. Whole genome sequence alignment and phylogenetic analysis showed high similarity between DENV-1-Jeddah-1-2011 strain and D1/H/IMTSSA/98/606 isolate (Asian genotype) reported from Djibouti in 1998. Further analysis of the full envelope gene revealed a close relationship between DENV-1-Jeddah-1-2011 strain and isolates reported between 2004-2006 from Jeddah as well as recent isolates from Somalia, suggesting the widespread of the Asian genotype in this region. These data suggest that strains belonging to the Asian genotype might have been introduced into Saudi Arabia long before 2004 most probably by African pilgrims and continued to circulate in western Saudi Arabia at least until 2011. Most importantly, these results indicate that pilgrims from dengue endemic regions can play an important role in the spread of new DENVs in Saudi Arabia and the rest of the world. Therefore, availability of complete genome sequences would serve as a reference for future epidemiological studies of DENV-1 viruses.

The NASA Mars Conference

NASA Astrophysics Data System (ADS)

Reiber, Duke B.

Papers about Mars and Mars exploration are presented, covering topics such as Martian history, geology, volcanism, channels, moons, atmosphere, meteorology, water on the planet, and the possibility of life. The unmanned exploration of Mars is discussed, including the Phobos Mission, the Mars Observer, the Mars Aeronomy Observer, the seismic network, Mars sample return missions, and the Mars Ball, an inflatable-sectored-tire rover concept. Issues dealing with manned exploration of Mars are examined, such as the reasons for exploring Mars, mission scenarios, a transportation system for routine visits, technologies for Mars expeditions, the human factors for Mars missions, life support systems, living and working on Mars, and the report of the National Commission on Space.

Orbital evidence for more widespread carbonate-bearing rocks on Mars

NASA Astrophysics Data System (ADS)

Wray, James J.; Murchie, Scott L.; Bishop, Janice L.; Ehlmann, Bethany L.; Milliken, Ralph E.; Wilhelm, Mary Beth; Seelos, Kimberly D.; Chojnacki, Matthew

2016-04-01

Carbonates are key minerals for understanding ancient Martian environments because they are indicators of potentially habitable, neutral-to-alkaline water and may be an important reservoir for paleoatmospheric CO2. Previous remote sensing studies have identified mostly Mg-rich carbonates, both in Martian dust and in a Late Noachian rock unit circumferential to the Isidis basin. Here we report evidence for older Fe- and/or Ca-rich carbonates exposed from the subsurface by impact craters and troughs. These carbonates are found in and around the Huygens basin northwest of Hellas, in western Noachis Terra between the Argyre basin and Valles Marineris, and in other isolated locations spread widely across the planet. In all cases they cooccur with or near phyllosilicates, and in Huygens basin specifically they occupy layered rocks exhumed from up to ~5 km depth. We discuss factors that might explain their observed regional distribution, arguments for why carbonates may be even more widespread in Noachian materials than presently appreciated and what could be gained by targeting these carbonates for further study with future orbital or landed missions to Mars.

Diversity of dengue virus-3 genotype III in Jeddah, Saudi Arabia.

PubMed

Hashem, Anwar M; Sohrab, Sayed S; El-Kafrawy, Sherif A; Abd-Alla, Adly M M; El-Ela, Saeid Abo; Abujamel, Turki S; Hassan, Ahmed M; Farraj, Suha A; Othman, Noura A; Charrel, Remi N; Azhar, Esam I

2018-07-01

Dengue is the most important arboviral disease in tropical and subtropical countries. Dispersal of the vector and an increase in migratory flow between countries have led to large epidemics and severe clinical outcomes. Over the past 20 years, dengue epidemics have become more wide-spread and frequent. Previous studies have shown that dengue is endemic in Jeddah, Makkah and Al-Madinah in western Saudi Arabia as well as in Jazan region in the southern part of the country. The four serotypes of dengue virus (DENV) have been reported from western Saudi Arabia. It has been suggested that pilgrims could play a significant and unique role in DENV-1 and DENV-2 introduction into Saudi Arabia, especially in the cities of Jeddah, Makkah and Al-Madinah during Hajj and Umrah seasons. However, only limited data on DENV-3 in Saudi Arabia are available. All available DENV-3 sequences published and unpublished from Saudi Arabia and other countries were retrieved from Genbank and gene sequence repository and phylogenetically analyzed to examine the diversity of DENV-3 into the city of Jeddah. Based on the analysis of the envelope gene and non-structural 1 (E/NS1) junction sequences, we show that there were at least four independent introductions of DENV-3, all from genotype III into Jeddah. The first introduction was most probably before 1997 as Saudi virus isolates from 1997 formed a cluster without any close relationship to other globally circulating isolates, suggesting their local circulation from previous introduction events. Two introductions were most probably in 2004 with isolates closely-related to isolates from Africa and India (Asia), in addition to another introduction in 2014 with isolates clustering with those from Singapore (Asia). Our data shows that only genotype III isolates of DENV-3 are circulating in Jeddah and highlights the potential role of pilgrims in DENV-3 importation into western Saudi Arabia and subsequent exportation to their home countries during Hajj

Recent Basal Melting of a Mid-Latitude Glacier on Mars

NASA Astrophysics Data System (ADS)

Butcher, Frances E. G.; Balme, M. R.; Gallagher, C.; Arnold, N. S.; Conway, S. J.; Hagermann, A.; Lewis, S. R.

2017-12-01

Evidence for past basal melting of young (late Amazonian-aged), debris-covered glaciers in Mars' mid-latitudes is extremely rare. Thus, it is widely thought that these viscous flow features (VFFs) have been perennially frozen to their beds. We identify an instance of recent, localized wet-based mid-latitude glaciation, evidenced by a candidate esker emerging from a VFF in a tectonic rift in Tempe Terra. Eskers are sedimentary ridges deposited in ice-walled meltwater conduits and are indicative of glacial melting. We compare the candidate esker to terrestrial analogues, present a geomorphic map of landforms in the rift, and develop a landsystem model to explain their formation. We propose that the candidate esker formed during a transient phase of wet-based glaciation. We then consider the similarity between the geologic setting of the new candidate esker and that of the only other candidate esker to be identified in association with an existing mid-latitude VFF; both are within tectonic graben/rifts proximal to volcanic provinces. Finally, we calculate potential basal temperatures for a range of VFF thicknesses, driving stresses, mean annual surface temperatures, and geothermal heat fluxes, which unlike previous studies, include the possible role of internal strain heating. Strain heating can form an important additional heat source, especially in flow convergence zones, or where ice is warmer due to elevated surface temperatures or geothermal heat flux. Elevated geothermal heat flux within rifts, perhaps combined with locally-elevated strain heating, may have permitted wet-based glaciation during the late Amazonian, when cold climates precluded more extensive wet-based glaciation on Mars.

Type 2 Diabetes Mellitus in Saudi Arabia: Major Challenges and Possible Solutions.

PubMed

Robert, Asirvatham Alwin; Al Dawish, Mohamed Abdulaziz; Braham, Rim; Musallam, Maha Ali; Al Hayek, Ayman Abdullah; Al Kahtany, Nasser Hazza

2017-01-01

The World Health Organization has ranked Saudi Arabia as having the second highest rate of diabetes in the Middle East (7th highest in the world) with an estimated population of 7 million living with diabetes and more than 3 million with pre-diabetes. This presents a pressing public health problem. Several challenges in diabetes management need to be tackled in Saudi Arabia, including the growing prevalence (chiefly among children and young adults), micro-and macrovascular complications, lifestyle changes, late diagnosis, poor awareness and high treatment costs. Over the last two decades, the Saudi population saw an increase in the expenses in healthcare and treatment of diabetes by more than 500%. In 2014, the health care budget was 180 billion (Saudi Riyal) of which 17 billion was spent on all Saudis, with an approximate 25 billion on the entire Saudi diabetic population. This implies that the direct expense of diabetes is costing Saudi Arabia around 13.9% of the total health expenditure. Therefore, unless a comprehensive epidemic control program/ multidisciplinary approach is stringently enforced, the diabetes mellitus burden on Saudi Arabia will probably increase to very serious levels. It is crucial to implement improved health and health-related quality of life of to those with diabetes, thus minimizing the social and personal expenses for diabetes care in Saudi Arabia. In this study we discuss the significant and major threats posed by diabetes mellitus to the Saudi population and recommend essential possible solutions to delay/ prevent this formidable issue. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Iodine deficiency in Saudi Arabia.

PubMed

Al-Nuaim, A R; Al-Mazrou, Y; Kamel, M; Al-Attas, O; Al-Daghari, N; Sulimani, R

1997-05-01

Data on the status of iodine deficiency in the Arabian peninsula is scarce. We have conducted a cross-sectional national epidemiological survey in Saudi Arabia to study the iodine status of Saudi schoolchildren, between eight and ten years, who were randomly selected, after taking into consideration the gender, provincial population and area distribution. Casual urine samples were collected and sent to the central laboratory for analysis. Clinical assessment for the presence of goiter was conducted in four areas with different geographical natures. The survey included 4638 subjects, and their median and mean (SD) of urinary iodine concentration was 18 and 17 m g/dL, respectively. We found provincial differences with respect to urinary iodine concentration and the percentage of subjects with urinary iodine concentration <10 m g/dL. The Southern province had the lowest median (11 m g/dL) and the highest percentage (45%) of subjects with urinary iodine concentration <10 m g/dL. On the other hand, subjects of the Western province had the highest median (24 m g/dL) and the lowest percentage (8%) of subjects with urinary iodine concentration <10 m g/dL. The clinical assessment revealed that the highest prevalence and more advanced grade of goiter (22%, 95% CI 19-25, grade 1; 8%, 95% CI 6-10, grade 2) was found in the Asir region, a high-altitude area in the Southern province. The lowest prevalence of goiter (4%, 95% CI 0.8-7.2, grade 1) was found in Gizan, an urban coastal community. There was a significant relationship between the prevalence of goiter and the urinary iodine concentration. The survey for iodine deficiency disorder (IDD) in Saudi Arabia has shown a mild degree of iodine deficiency in the Southern province. Odds ratio (OR) was used to study the statistical relationship between the prevalence of goiter and the urinary iodine concentration. There is a need to launch a control program to ensure the exclusive availability of iodized salt in Saudi Arabia

Direct Geolocation of TerraSAR-X Spotlight Mode Image and Error Correction

NASA Astrophysics Data System (ADS)

Zhou, Xiao; Zeng, Qiming; Jiao, Jian; Zhang, Jingfa; Gong, Lixia

2013-01-01

The GERMAN TerraSAR-X mission was launched in June 2007, operating a versatile new-generation SAR sensor in X-band. Its Spotlight mode providing SAR images at very high resolution of about 1m. The product’s specified 3-D geolocation accuracy is tightened to 1m according to the official technical report. However, this accuracy is able to be achieved relies on not only robust mathematical basis of SAR geolocation, but also well knowledge of error sources and their correction. The research focuses on geolocation of TerraSAR-X spotlight image. Mathematical model and resolving algorithms have been analyzed. Several error sources have been researched and corrected especially. The effectiveness and accuracy of the research was verified by the experiment results.

Consistency of two global MODIS aerosol products over ocean on Terra and Aqua CERES SSF datasets

NASA Astrophysics Data System (ADS)

Ignatov, Alexander; Minnis, Patrick; Wielicki, Bruce; Loeb, Norman G.; Remer, Lorraine A.; Kaufman, Yoram J.; Miller, Walter F.; Sun-Mack, Sunny; Laszlo, Istvan; Geier, Erika B.

2004-12-01

MODIS aerosol retrievals over ocean from Terra and Aqua platforms are available from the Clouds and the Earth's Radiant Energy System (CERES) Single Scanner Footprint (SSF) datasets generated at NASA Langley Research Center (LaRC). Two aerosol products are reported side by side. The primary M product is generated by subsetting and remapping the multi-spectral (0.44 - 2.1 μm) MOD04 aerosols onto CERES footprints. MOD04 processing uses cloud screening and aerosol algorithms developed by the MODIS science team. The secondary (AVHRR-like) A product is generated in only two MODIS bands: 1 and 6 on Terra, and ` and 7 on Aqua. The A processing uses NASA/LaRC cloud-screening and NOAA/NESDIS single channel aerosol algorthm. The M and A products have been documented elsewhere and preliminarily compared using two weeks of global Terra CERES SSF (Edition 1A) data in December 2000 and June 2001. In this study, the M and A aerosol optical depths (AOD) in MODIS band 1 and (0.64 μm), τ1M and τ1A, are further checked for cross-platform consistency using 9 days of global Terra CERES SSF (Edition 2A) and Aqua CERES SSF (Edition 1A) data from 13 - 21 October 2002.

An overview of wetlands of Saudi Arabia: Values, threats, and perspectives.

PubMed

Al-Obaid, Sami; Samraoui, Boudjéma; Thomas, Jacob; El-Serehy, Hamed A; Alfarhan, Ahmed H; Schneider, Wolfgang; O'Connell, Mark

2017-02-01

The wetlands of Saudi Arabia are located in a water-stressed region that is highly vulnerable to climate and other global changes. Sebkhas, mudflats, mangroves, and wadis are the dominant wetlands in the arid regions of North Africa and the Arabian Peninsula. These unique wetlands are recognized as a sanctuary for biodiversity and for their economic services generated from mineral extraction, agriculture, and grazing. Despite their ecological values and societal services, the long-term permanence of Saudi Arabia's wetlands faces strong challenges resulting from human activities associated with sustained population growth, habitat degradation, and coastal development. This paper consolidates a literature review of Saudi Arabia's wetlands from local to global importance, highlights their biodiversity, and identifies threats and evolution of these vulnerable ecosystems in the arid Arabian Peninsula by focusing on the status of key freshwater taxa (Odonata, freshwater fishes, amphibians, and waterbirds) and documenting changes affecting important wetlands.

Mars-GRAM 2010: Improving the Precision of Mars-GRAM

NASA Technical Reports Server (NTRS)

Justh, H. L.; Justus, C. G.; Ramey, H. S.

2011-01-01

It has been discovered during the Mars Science Laboratory (MSL) site selection process that the Mars Global Reference Atmospheric Model (Mars-GRAM) when used for sensitivity studies for Thermal Emission Spectrometer (TES) MapYear=0 and large optical depth values, such as tau=3, is less than realistic. Mars-GRAM's perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). Mars-GRAM 2005 has been validated against Radio Science data, and both nadir and limb data from TES. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: (1) TES mapping year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from NASA Ames Mars General Circulation Model (MGCM) results driven by selected values of globally-uniform dust optical depth, or (2) TES mapping years 1 and 2, with Mars-GRAM data coming from MGCM results driven by observed TES dust optical depth. From the surface to 80 km altitude, Mars-GRAM is based on NASA Ames MGCM. Above 80 km, Mars-GRAM is based on the University of Michigan Mars Thermospheric General Circulation Model (MTGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This choice of data has led to discrepancies that have become apparent during recent sensitivity studies for MapYear=0 and large optical depths. Unrealistic energy absorption by time-invariant atmospheric dust leads to an unrealistic thermal energy balance on the polar caps. The outcome is an inaccurate cycle of condensation/sublimation of the polar caps and, as a consequence, an inaccurate cycle of total atmospheric mass and global-average surface pressure. Under an assumption of unchanged temperature profile and hydrostatic equilibrium, a given percentage change in surface pressure would produce a corresponding percentage

Gulfnet in Saudi Arabia: An Overview.

ERIC Educational Resources Information Center

Al-Khulaifi, M.

1995-01-01

Provides an overview of the Gulfnet Academic network, set in the context of development in Saudi Arabia and the establishment of King Abdulaziz City for Science and Technology (KACST). Goals and objectives of KACST are presented, Gulfnet members in the Gulf States are listed, and Gulfnet management, services, and facilities are discussed. (JKP)

Utilization of penile prosthesis and male incontinence prosthetics in Saudi Arabia.

PubMed

Alwaal, Amjad; Al-Sayyad, Ahmad J

2017-01-01

Erectile dysfunction is a prevalent disease affecting over 50% of men between the ages of 40 and 70 years. Penile prosthesis represents the end of the line treatment when other less invasive therapies fail or are contraindicated. Male stress urinary incontinence can significantly diminish quality of life and lead to embarrassment and social withdrawal. Surgical therapies, such as male urethral slings and artificial urinary sphincters (AUS), are considered effective and safe treatments for male stress incontinence. No data exist on the utilization of penile prosthesis or male incontinence surgical treatment in Saudi Arabia. Generally, urological prosthetic surgery is performed either in private hospitals or in government hospitals. Our aim was to assess the trend of penile prosthesis and male incontinence device utilization in Saudi Arabia. We utilized sales' data of penile prosthetics, male slings, and AUS from the only two companies selling these devices in Saudi Arabia (AMS ® and Coloplast ® ), from January 2013 to December 2016. There were 2599 penile prosthesis implantation procedures done in the study period, with 67% of them performed in private institutions. There was a progressively increased use of penile prosthetics which nearly doubled from 2013 to 2016. The main type of prosthesis utilized was the semirigid type 70% versus 11% of the 2-piece inflatable and 17% of the 3-piece inflatable device. Only 10 slings and 31 AUS were inserted during the same study period. There is an increased utilization of penile prosthetics in Saudi Arabia. The private sector performs the majority of penile prosthesis procedures, and most of them are of the semirigid type. The governmental sector is more likely to perform inflatable penile prosthesis and male incontinence device procedures. Male incontinence prosthetics' use is very limited in Saudi Arabia.

Virtual water content for meat and egg production through livestock farming in Saudi Arabia

NASA Astrophysics Data System (ADS)

Chowdhury, Shakhawat; Ouda, Omar K. M.; Papadopoulou, Maria P.

2017-12-01

The concept of virtual water content (VWC) may facilitate an understanding of total water demand for commodity production. The water consumption for livestock production forms a significant fraction of freshwater demand in arid regions, i.e., Saudi Arabia. In this paper, VWC was estimated for different livestocks in the 13 regions of Saudi Arabia. The VWC for camel production was also estimated, which has not been investigated in the previous studies. The overall VWC for livestock in Saudi Arabia was about 10.5 and 8.9 billion m3 in 2006 and 2010, respectively. This study shows the decreasing trend of overall VWC in producing livestock in Saudi Arabia. The VWC were highest in Riyadh followed by Eastern region, Qaseem, Hail, and Makkah with ranges of 3587-4112, 1684-2044, 1007-1331, 644-810, and 504-715 million m3/year, respectively. The results demonstrate that a shift in diet from the high VWC meat to low VWC meat may reduce the overall VWC for livestock production. The findings of this analysis provide an assessment of the quantity and trend of water demand for livestock production in Saudi Arabia, which is useful to assess the development of an information-based agricultural water management strategy.

Mars Odyssey Seen by Mars Global Surveyor 3-D

NASA Image and Video Library

2005-05-19

This stereoscopic picture of NASA Mars Odyssey spacecraft was created from two views of that spacecraft taken by the Mars Orbiter Camera on NASA Mars Global Surveyor. 3D glasses are necessary to view this image.

CERES ERBE-like Instantaneous TOA Estimates (ES-8) in HDF (CER_ES8_Terra-FM1_Edition2)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The ES-8 archival data product contains a 24-hour, single-satellite, instantaneous view of scanner fluxes at the top-of-atmosphere (TOA) reduced from spacecraft altitude unfiltered radiances using Earth Radiation Budget Experiment (ERBE) scanner Inversion algorithms and the ERBE shortwave (SW) and longwave (LW) Angular Distribution Models (ADMs). The ES-8 also includes the total (TOT), SW, LW, and window (WN) channel radiometric data; SW, LW, and WN unfiltered radiance values; and the ERBE scene identification for each measurement. These data are organized according to the CERES 3.3-second scan into 6.6-second records. As long as there is one valid scanner measurement within a record, the ES-8 record will be generated. The following CERES ES8 data sets are currently available: CER_ES8_TRMM-PFM_Edition1 CER_ES8_TRMM-PFM_Edition2 CER_ES8_TRMM-PFM_Transient-Ops2 CER_ES8_Terra-FM1_Edition1 CER_ES8_Terra-FM2_Edition1 CER_ES8_Terra-FM1_Edition2 CER_ES8_Terra-FM2_Edition2 CER_ES8_Aqua-FM3_Edition1 CER_ES8_Aqua-FM4_Edition1 CER_ES8_Aqua-FM3_Edition2 CER_ES8_Aqua-FM4_Edition2 CER_ES8_Aqua-FM3_Edition1-CV CER_ES8_Aqua-FM4_Edition1-CV CER_ES8_Terra-FM1_Edition1-CV CER_ES8_Terra-FM1_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2006-01-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

CERES ERBE-like Instantaneous TOA Estimates (ES-8) in HDF (CER_ES8_Terra-FM2_Edition1)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator)

The ES-8 archival data product contains a 24-hour, single-satellite, instantaneous view of scanner fluxes at the top-of-atmosphere (TOA) reduced from spacecraft altitude unfiltered radiances using Earth Radiation Budget Experiment (ERBE) scanner Inversion algorithms and the ERBE shortwave (SW) and longwave (LW) Angular Distribution Models (ADMs). The ES-8 also includes the total (TOT), SW, LW, and window (WN) channel radiometric data; SW, LW, and WN unfiltered radiance values; and the ERBE scene identification for each measurement. These data are organized according to the CERES 3.3-second scan into 6.6-second records. As long as there is one valid scanner measurement within a record, the ES-8 record will be generated. The following CERES ES8 data sets are currently available: CER_ES8_TRMM-PFM_Edition1 CER_ES8_TRMM-PFM_Edition2 CER_ES8_TRMM-PFM_Transient-Ops2 CER_ES8_Terra-FM1_Edition1 CER_ES8_Terra-FM2_Edition1 CER_ES8_Terra-FM1_Edition2 CER_ES8_Terra-FM2_Edition2 CER_ES8_Aqua-FM3_Edition1 CER_ES8_Aqua-FM4_Edition1 CER_ES8_Aqua-FM3_Edition2 CER_ES8_Aqua-FM4_Edition2 CER_ES8_Aqua-FM3_Edition1-CV CER_ES8_Aqua-FM4_Edition1-CV CER_ES8_Terra-FM1_Edition1-CV CER_ES8_Terra-FM1_Edition1-CV. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1997-12-27; Stop_Date=2005-11-01] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 day; Temporal_Resolution_Range=Daily - < Weekly].

Saudi Arabia: Background and U.S. Relations

DTIC Science & Technology

2009-04-30

President of the Middle East Policy Council, served as U.S. Ambassador to Saudi Arabia from 1989 to 1992. Tabassum Zakaria, “Analysis—Saudi smile likely...that may have contributed to the development of terrorist 25 Tabassum Zakaria, “Analysis—Saudi smile

Evidence of mud volcanism rooted in gas hydrate-rich cryosphere linking surface and subsurface for the search for life on Mars

NASA Astrophysics Data System (ADS)

De Toffoli, Barbara; Pozzobon, Riccardo; Mazzarini, Francesco; Massironi, Matteo; Cremonese, Gabriele

2017-04-01

We mapped around 6000 mounds in three different portions of the Martian surface on an average area of about 90.000 Km2 for each region. The study areas are located in Hellas basin, Utopia basin and a portion of the Northern Plains lying north of Arabia Terra, between Acidalia and Utopia Planitia. The aim of the study was to understand the nature of the observed features, particularly if they could be interpreted as mud volcanoes or not, and improve our knowledge about the Martian mound fields origin. The analysis of Context Camera (onboard Mars Reconnaissance Orbiter) images showed circular, elliptical and coalescent mounds with central and/or distal pits and flow features such as concentric annular lobes around the source pits and apron-like extensions. We produced DTMs and then high-to-diameter morphometric analysis on two groups of mounds located in Utopia and Hellas basins to enhance the geomorphological observations. We inferred, by means of cluster and fractal analyses, the thickness of the medium cracked by connected fractures and, consequently, the depths of reservoirs that fed the mounds. We found that the fields, which are seated at different latitudes, has been fed, at least partially, by reservoirs located at the base of the gas hydrate stability zone according to Clifford et al., 2010. This evidence produces a meaningful relationship between the clathrates distribution underneath the Martian surface and the occurrence of mound fields on the surface leading to the assumption that the involvement of water, ostensibly as a result of gas hydrate dissociation, plays a key role in the subsurface processes that potentially worked as triggers. These outcomes corroborate the hypothesis that the mapped mounds are actually mud volcanoes and make these structures outstanding targets for astrobiology and habitability studies. In fact, mud volcanoes, extruding material from depths that are still not affordable by our present-day instrumentations, could have sampled

Independent Verification of Mars-GRAM 2010 with Mars Climate Sounder Data

NASA Technical Reports Server (NTRS)

Justh, Hilary L.; Burns, Kerry L.

2014-01-01

The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission and engineering applications. Applications of Mars-GRAM include systems design, performance analysis, and operations planning for aerobraking, entry, descent and landing, and aerocapture. Atmospheric influences on landing site selection and long-term mission conceptualization and development can also be addressed utilizing Mars-GRAM. Mars-GRAM's perturbation modeling capability is commonly used, in a Monte Carlo mode, to perform high-fidelity engineering end-to-end simulations for entry, descent, and landing. Mars-GRAM is an evolving software package resulting in improved accuracy and additional features. Mars-GRAM 2005 has been validated against Radio Science data, and both nadir and limb data from the Thermal Emission Spectrometer (TES). From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). Above 80 km, Mars-GRAM is based on the University of Michigan Mars Thermospheric General Circulation Model (MTGCM). The most recent release of Mars-GRAM 2010 includes an update to Fortran 90/95 and the addition of adjustment factors. These adjustment factors are applied to the input data from the MGCM and the MTGCM for the mapping year 0 user-controlled dust case. The adjustment factors are expressed as a function of height (z), latitude and areocentric solar longitude (Ls).

Heavy Thunderstorm Synoptic Climatology and Forcing Mechanisms in Saudi Arabia.

NASA Astrophysics Data System (ADS)

Ghulam, Ayman S.

2010-05-01

Meteorologists are required to provide accurate and comprehensive weather information for planning and operational aviation, agricultural, water projects and also for the public. In general, weather phenomena such as thunderstorms over the area between the tropics and the middle latitudes are not fully understood, particularly in the Middle East area, for many reasons such as: 1) the complexity of the nature of the climate due to the wide-ranging diversity in the topography and landscape in the area; 2) the lack of meteorological data in the area; and 3) the lack of studies on local weather situations. In arid regions such as Saudi Arabia, the spatial and temporal variation of thunderstorms and associated rainfall are essential in determining their effects on social and economic conditions. Thunderstorms form rapidly, due to the fact that the significant heating of the air from the surface and the ensuing rainfall usually occurs within a short period of time. Thus, understanding thunderstorms and rainfall distribution in time and space would be useful for hydrologists, meteorologists and for environmental studies. Research all over the world has shown, however, that consideration of local factors like Low Level Jets (LLJ), moisture flux, sea breezes, and the Red Sea Convergence Zone (RSCZ) would be valuable in thunderstorm prediction. The combined effects of enhanced low-level moisture convergence and layer destabilization due to upslope flow over mountainous terrain has been shown to be responsible for thunderstorm development in otherwise non-favourable conditions. However, there might be other synoptic features associated with heavy thunderstorms or cause them, but these features have not been investigated in any research in Saudi Arabia. Thus, relating the local weather and synoptic situations with those over the middle latitudes will provide a valuable background for the forecasters to issue the medium-range forecasts which are important for many projects

Additions to Mars Global Reference Atmospheric Model (MARS-GRAM)

NASA Technical Reports Server (NTRS)

Justus, C. G.; James, Bonnie

1992-01-01

Three major additions or modifications were made to the Mars Global Reference Atmospheric Model (Mars-GRAM): (1) in addition to the interactive version, a new batch version is available, which uses NAMELIST input, and is completely modular, so that the main driver program can easily be replaced by any calling program, such as a trajectory simulation program; (2) both the interactive and batch versions now have an option for treating local-scale dust storm effects, rather than just the global-scale dust storms in the original Mars-GRAM; and (3) the Zurek wave perturbation model was added, to simulate the effects of tidal perturbations, in addition to the random (mountain wave) perturbation model of the original Mars-GRAM. A minor modification was also made which allows heights to go 'below' local terrain height and return 'realistic' pressure, density, and temperature, and not the surface values, as returned by the original Mars-GRAM. This feature will allow simulations of Mars rover paths which might go into local 'valley' areas which lie below the average height of the present, rather coarse-resolution, terrain height data used by Mars-GRAM. Sample input and output of both the interactive and batch versions of Mars-GRAM are presented.

Additions to Mars Global Reference Atmospheric Model (Mars-GRAM)

NASA Technical Reports Server (NTRS)

Justus, C. G.

1991-01-01

Three major additions or modifications were made to the Mars Global Reference Atmospheric Model (Mars-GRAM): (1) in addition to the interactive version, a new batch version is available, which uses NAMELIST input, and is completely modular, so that the main driver program can easily be replaced by any calling program, such as a trajectory simulation program; (2) both the interactive and batch versions now have an option for treating local-scale dust storm effects, rather than just the global-scale dust storms in the original Mars-GRAM; and (3) the Zurek wave perturbation model was added, to simulate the effects of tidal perturbations, in addition to the random (mountain wave) perturbation model of the original Mars-GRAM. A minor modification has also been made which allows heights to go below local terrain height and return realistic pressure, density, and temperature (not the surface values) as returned by the original Mars-GRAM. This feature will allow simulations of Mars rover paths which might go into local valley areas which lie below the average height of the present, rather coarse-resolution, terrain height data used by Mars-GRAM. Sample input and output of both the interactive and batch version of Mars-GRAM are presented.

TERRA and hnRNPA1 orchestrate an RPA-to-POT1 switch on telomeric single-stranded DNA.

PubMed

Flynn, Rachel Litman; Centore, Richard C; O'Sullivan, Roderick J; Rai, Rekha; Tse, Alice; Songyang, Zhou; Chang, Sandy; Karlseder, Jan; Zou, Lee

2011-03-24

Maintenance of telomeres requires both DNA replication and telomere 'capping' by shelterin. These two processes use two single-stranded DNA (ssDNA)-binding proteins, replication protein A (RPA) and protection of telomeres 1 (POT1). Although RPA and POT1 each have a critical role at telomeres, how they function in concert is not clear. POT1 ablation leads to activation of the ataxia telangiectasia and Rad3-related (ATR) checkpoint kinase at telomeres, suggesting that POT1 antagonizes RPA binding to telomeric ssDNA. Unexpectedly, we found that purified POT1 and its functional partner TPP1 are unable to prevent RPA binding to telomeric ssDNA efficiently. In cell extracts, we identified a novel activity that specifically displaces RPA, but not POT1, from telomeric ssDNA. Using purified protein, here we show that the heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) recapitulates the RPA displacing activity. The RPA displacing activity is inhibited by the telomeric repeat-containing RNA (TERRA) in early S phase, but is then unleashed in late S phase when TERRA levels decline at telomeres. Interestingly, TERRA also promotes POT1 binding to telomeric ssDNA by removing hnRNPA1, suggesting that the re-accumulation of TERRA after S phase helps to complete the RPA-to-POT1 switch on telomeric ssDNA. Together, our data suggest that hnRNPA1, TERRA and POT1 act in concert to displace RPA from telomeric ssDNA after DNA replication, and promote telomere capping to preserve genomic integrity.

English Language Teaching Profile: Saudi Arabia.

ERIC Educational Resources Information Center

British Council, London (England). English Language and Literature Div.

The role and status of English in Saudi Arabia are examined, with attention directed to: (1) English within the education system; (2) teachers of English; (3) English outside the education system; (4) materials support; (5) British support for the teaching of English; and (6) English syllabi at intermediate, secondary, and higher education levels.…

Reprioritizing current research trends in medical education: a reflection on research activities in Saudi Arabia.

PubMed

Obeidat, Akef S; Alhaqwi, Ali Ibrahim; Abdulghani, Hamza Mohammad

2015-04-01

There are numerous national efforts to determine and develop research priorities of medical education in Saudi Arabia. These priorities were first proposed in 2010 by "Dr Al-Khuli's Chair for Developing Medical Education in Saudi Arabia". The proposed priority domains were: curriculum, students, faculty, and quality assurance and accreditation. To investigate publications in medical education at the national and international levels in areas relating to these proposed priorities. Electronic search within PubMed database for papers relating to each domain of priority was conducted at national and international levels in the last three years, using the same keywords as the priority domains, but only confined to undergraduate medical education. Out of 3145 articles retrieved when searching with keyword as broad as "undergraduate medical curriculum" only 81 articles worldwide and 3 articles from Saudi Arabia were dealing with curriculum related issues as a whole. Further search on the sub-domains "effective strategies to manage undergraduate curriculum" and "undergraduate medical education models", resulted in the retrieval of few articles worldwide and none from Saudi Arabia. At the national level, there were 63 publications from Saudi Arabia that were either course (topic)-specific or could not be classified under the four domains specified by Dr Al-Khuli's Chair. Research activities in medical education in Saudi Arabia in the last 3 years showed diversity and lack of focus in the research priorities. Efforts of academic and research centers should continue to monitor and encourage these activities toward achieving the recommended priorities.

Issues engulfed Saudi Arabia construction workers

NASA Astrophysics Data System (ADS)

Al-Emad, N. H.; Rahman, I. A.

2018-04-01

This paper presents an exploratory study conducted in Makkah city to uncover issues faced by construction workers from the construction leaders’ perspective. Eleven construction leaders/experts were interviewed to unleash their experiences on handling the foreign workers working in Makkah construction projects. Most of the experts are senior management staffs with more than 10 years’ working experience in Saudi Arabia construction industry. The interviews were carried out in semi structured mode where all the information was captured manually and also electronically. The identified issues were sorted based on its commonality into 10 clusters. Hence in each cluster, the numbers of issue considered by the experts are reflecting the importance of that particular cluster. The result of the clusters according to the number of issues mentioned by the experts are safety issues, restricted government regulation, demotivated issues, lack of quality workers, poor living quality, communication barriers, adaption issues, poor attitudes, lack of logistical arrangements and lack of education. With these identified issues it will assist the construction players in the construction industry of Saudi Arabia in dealing with their workers.

MarsQuest: Bringing the Excitement of Mars Exploration to the Public

NASA Astrophysics Data System (ADS)

Dusenbery, P. B.; Morrow, C. A.; Harold, J. B.; Klug, S. L.

2002-12-01

We are living in an extraordinary era of Mars exploration. NASA's Odyssey spacecraft has recently discovered vast amounts of hydrogen beneath the surface of Mars, suggesting the presence of sub-surface ice. Two Mars Exploration Rovers are scheduled to land in early 2004. To bring the excitement and discoveries of Mars exploration to the public, the Space Science Institute (SSI) of Boulder, CO, has developed a comprehensive Mars Education Program that includes: 1) large and small traveling exhibits, 2) workshops for museum and classroom educators (in partnership with the Mars Education Program at Arizona State University (ASU)), and 3) an interactive Website called MarsQuest Online (in partnership with TERC and JPL). All three components will be presented and offered as a good model for actively involving scientists and their discoveries to improve science education in museums and the classroom. The centerpiece of SSI's Mars Education Program is the 5,000-square-foot traveling exhibition, MarsQuest: Exploring the Red Planet, which was developed with support from the National Science Foundation (NSF), NASA, and several corporate donors. The MarsQuest exhibit is nearing the end of a highly successful, fully-booked three-year tour. The Institute plans to send an enhanced and updated MarsQuest on a second three-year tour and is also developing Destination: Mars, a mini-version of MarsQuest designed for smaller venues. Workshops for museum educators, docents, and local teachers are conducted at host sites. These workshops were developed collaboratively by Dr. Cheri Morrow, SSI's Education and Public Outreach Manager, and Sheri Klug, Director of the Mars K-12 Education Program at ASU. They are designed to inspire and empower participants to extend the excitement and science content of the exhibitions into classrooms and museum-based education programs in an ongoing fashion. The MarsQuest Online project is developing a Website that will use the MarsQuest exhibit as a

MarsQuest: Bringing the Excitement of Mars Exploration to the Public

NASA Astrophysics Data System (ADS)

Dusenbery, P. B.; Morrow, C. A.; Harold, J. B.; Klug, S. L.

2002-09-01

We are living in an extraordinary era of Mars exploration. NASA's Odyssey spacecraft has recently discovered vast amounts of hydrogen beneath the surface of Mars, suggesting the presence of sub-surface ice. Two Mars Exploration Rovers are scheduled to land in early 2004. To bring the excitement and discoveries of Mars exploration to the public, the Space Science Institute (SSI) of Boulder, CO, has developed a comprehensive Mars Education Program that includes: 1) large and small traveling exhibits, 2) workshops for museum and classroom educators (in partnership with the Mars Education Program at Arizona State University (ASU)), and 3) an interactive Website called MarsQuest Online (in partnership with TERC and JPL). All three components will be presented and offered as a good model for actively involving scientists and their discoveries to improve science education in museums and the classroom. The centerpiece of SSI's Mars Education Program is the 5,000-square-foot traveling exhibition, MarsQuest: Exploring the Red Planet, which was developed with support from the National Science Foundation (NSF), NASA, and several corporate donors. The MarsQuest exhibit is nearing the end of a highly successful, fully-booked three-year tour. The Institute plans to send an enhanced and updated MarsQuest on a second three-year tour and is also developing Destination: Mars, a mini-version of MarsQuest designed for smaller venues. Workshops for museum educators, docents, and local teachers are conducted at host sites. These workshops were developed collaboratively by Dr. Cheri Morrow, SSI's Education and Public Outreach Manager, and Sheri Klug, Director of the Mars K-12 Education Program at ASU. They are designed to inspire and empower participants to extend the excitement and science content of the exhibitions into classrooms and museum-based education programs in an ongoing fashion. The MarsQuest Online project is developing a Website that will use the MarsQuest exhibit as a

Teachers' Role in the Development of EFL Curriculum in Saudi Arabia: The Marginalised Status

ERIC Educational Resources Information Center

Alnefaie, Sultan Klaib

2016-01-01

Teachers' participation in curriculum development is an area of research that has not been given adequate attention in the context of Saudi Arabia. This critical exploratory study investigated the issue of teachers' marginalisation in the curriculum development process with the aim of problematising power relations in Saudi Arabia's education…

Applications of Mars Global Reference Atmospheric Model (Mars-GRAM 2005) Supporting Mission Site Selection for Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Justh, Hilary L.; Justus, Carl G.

2008-01-01

The Mars Global Reference Atmospheric Model (Mars-GRAM 2005) is an engineering level atmospheric model widely used for diverse mission applications. An overview is presented of Mars-GRAM 2005 and its new features. One new feature of Mars-GRAM 2005 is the 'auxiliary profile' option. In this option, an input file of temperature and density versus altitude is used to replace mean atmospheric values from Mars-GRAM's conventional (General Circulation Model) climatology. An auxiliary profile can be generated from any source of data or alternate model output. Auxiliary profiles for this study were produced from mesoscale model output (Southwest Research Institute's Mars Regional Atmospheric Modeling System (MRAMS) model and Oregon State University's Mars mesoscale model (MMM5)model) and a global Thermal Emission Spectrometer(TES) database. The global TES database has been specifically generated for purposes of making Mars-GRAM auxiliary profiles. This data base contains averages and standard deviations of temperature, density, and thermal wind components,averaged over 5-by-5 degree latitude-longitude bins and 15 degree L(s) bins, for each of three Mars years of TES nadir data. Results are presented using auxiliary profiles produced from the mesoscale model output and TES observed data for candidate Mars Science Laboratory (MSL) landing sites. Input parameters rpscale (for density perturbations) and rwscale (for wind perturbations) can be used to "recalibrate" Mars-GRAM perturbation magnitudes to better replicate observed or mesoscale model variability.

Tectonic evolution of Western Ishtar Terra, Venus

NASA Astrophysics Data System (ADS)

Marinangeli, Lucia

1997-03-01

A detailed geological mapping based on Magellan data has been done in Western Ishtar Terra from 300-330 deg W to 65-75 deg N. The area studied comprises three main phisiografic provinces, Atropos Tessera, Akna Montes and North-Western Lakshmi Planum. The purposes of this study are (1) to recognize the tectonism of this area and investigate its type, direction, intensity, distribution and age relationships, (2) to define the link between the formation of the Akna mountain belt and the tectonic deformation in adjacent Tessera and Lakshmi Planum.

Two drastically different climate states on an Earth-like terra-planet

NASA Astrophysics Data System (ADS)

Kalidindi, Sirisha; Reick, Christian H.; Raddatz, Thomas; Claussen, Martin

2018-06-01

We study an Earth-like terra-planet (water-limited terrestrial planet) with an overland recycling mechanism bringing fresh water back from the high latitudes to the low latitudes. By performing model simulations for such a planet we find two drastically different climate states for the same set of boundary conditions and parameter values: a cold and wet (CW) state with dominant low-latitude precipitation and a hot and dry (HD) state with only high-latitude precipitation. We notice that for perpetual equinox conditions, both climate states are stable below a certain threshold value of background soil albedo while above the threshold only the CW state is stable. Starting from the HD state and increasing background soil albedo above the threshold causes an abrupt shift from the HD state to the CW state resulting in a sudden cooling of about 35 °C globally, which is of the order of the temperature difference between present day and the Snowball Earth state. When albedo starting from the CW state is reduced down to zero the terra-planet does not shift back to the HD state (no closed hysteresis). This is due to the high cloud cover in the CW state hiding the surface from solar irradiation so that surface albedo has only a minor effect on the top of the atmosphere radiation balance. Additional simulations with present-day Earth's obliquity all lead to the CW state, suggesting a similar abrupt transition from the HD state to the CW state when increasing obliquity from zero. Our study also has implications for the habitability of Earth-like terra-planets. At the inner edge of the habitable zone, the higher cloud cover in the CW state cools the planet and may prevent the onset of a runaway greenhouse state. At the outer edge, the resupply of water at low latitudes stabilizes the greenhouse effect and keeps the planet in the HD state and may prevent water from getting trapped at high latitudes in frozen form. Overall, the existence of bistability in the presence of an

Considering the formation of hematite spherules on Mars by freezing aqueous hematite nanoparticle suspensions

NASA Astrophysics Data System (ADS)

Sexton, M. R.; Elwood Madden, M. E.; Swindle, A. L.; Hamilton, V. E.; Bickmore, B. R.; Elwood Madden, A. S.

2017-04-01

The enigmatic and unexpected occurrence of coarse crystalline (gray) hematite spherules at Terra Meridiani on Mars in association with deposits of jarosite-rich sediments fueled a variety of hypotheses to explain their origin. In this study, we tested the hypothesis that freezing of aqueous hematite nanoparticle suspensions, possibly produced from low-temperature weathering of jarosite-bearing deposits, could produce coarse-grained hematite aggregate spherules. We synthesized four hematite nanoparticle suspensions with a range of sizes and morphologies and performed freezing experiments. All sizes of hematite nanoparticles rapidly aggregate during freezing. Regardless of the size or shape of the initial starting material, they rapidly collect into aggregates that are then too big to push in front of a stable advancing ice front, leading to incohesive masses of particles, rather than solid spherules. We also explored the effects of "seed" silicates, a matrix of sand grains, various concentrations of NaCl and CaCl2, and varying the freezing temperature on hematite nanoparticle aggregation. However, none of these factors resulted in mm-scale spherical aggregates. By comparing our measured freezing rates with empirical and theoretical values from the literature, we conclude that the spherules on Mars could not have been produced through the freezing of aqueous hematite nanoparticle suspensions; ice crystallization front instability disrupts the aggregation process and prevents the formation of mm-scale continuous aggregates.