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Jie Zhou - One of the best experts on this subject based on the ideXlab platform.
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A new method to estimate changes in Glacier surface elevation based on polynomial fitting of sparse ICESat—GLAS footprints
Sensors, 2017Co-Authors: Tianjin Huang, Massimo Menenti, Jing Lu, Li Jia, Jie Zhou, Guangcheng HuAbstract:We present in this paper a polynomial fitting method applicable to segments of footprints measured by the Geoscience Laser Altimeter System (GLAS) to estimate Glacier thickness change. Our modification makes the method applicable to complex topography, such as a large Mountain Glacier. After a full analysis of the planar fitting method to characterize errors of estimates due to complex topography, we developed an improved fitting method by adjusting a binary polynomial surface to local topography. The improved method and the planar fitting method were tested on the accumulation areas of the Naimona’nyi Glacier and Yanong Glacier on along-track facets with lengths of 1000 m, 1500 m, 2000 m, and 2500 m, respectively. The results show that the improved method gives more reliable estimates of changes in elevation than planar fitting. The improved method was also tested on Guliya Glacier with a large and relatively flat area and the Chasku Muba Glacier with very complex topography. The results in these test sites demonstrate that the improved method can give estimates of Glacier thickness change on Glaciers with a large area and a complex topography. Additionally, the improved method based on GLAS Data and Shuttle Radar Topography Mission-Digital Elevation Model (SRTM-DEM) can give estimates of Glacier thickness change from 2000 to 2008/2009, since it takes the 2000 SRTM-DEM as a reference, which is a longer period than 2004 to 2008/2009, when using the GLAS data only and the planar fitting method.
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a new method to estimate changes in Glacier surface elevation based on polynomial fitting of sparse icesat glas footprints
Sensors, 2017Co-Authors: Tianjin Huang, Massimo Menenti, Li Jia, Jie ZhouAbstract:We present in this paper a polynomial fitting method applicable to segments of footprints measured by the Geoscience Laser Altimeter System (GLAS) to estimate Glacier thickness change. Our modification makes the method applicable to complex topography, such as a large Mountain Glacier. After a full analysis of the planar fitting method to characterize errors of estimates due to complex topography, we developed an improved fitting method by adjusting a binary polynomial surface to local topography. The improved method and the planar fitting method were tested on the accumulation areas of the Naimona’nyi Glacier and Yanong Glacier on along-track facets with lengths of 1000 m, 1500 m, 2000 m, and 2500 m, respectively. The results show that the improved method gives more reliable estimates of changes in elevation than planar fitting. The improved method was also tested on Guliya Glacier with a large and relatively flat area and the Chasku Muba Glacier with very complex topography. The results in these test sites demonstrate that the improved method can give estimates of Glacier thickness change on Glaciers with a large area and a complex topography. Additionally, the improved method based on GLAS Data and Shuttle Radar Topography Mission-Digital Elevation Model (SRTM-DEM) can give estimates of Glacier thickness change from 2000 to 2008/2009, since it takes the 2000 SRTM-DEM as a reference, which is a longer period than 2004 to 2008/2009, when using the GLAS data only and the planar fitting method.
David R. Marchant - One of the best experts on this subject based on the ideXlab platform.
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Remnant buried ice in the equatorial regions of Mars: Morphological indicators associated with the Arsia Mons tropical Mountain Glacier deposits
Planetary and Space Science, 2015Co-Authors: Kathleen E. Scanlon, James W. Head, David R. MarchantAbstract:The fan-shaped deposit (FSD) on the western and northwestern flanks of Arsia Mons is the remnant of tropical Mountain Glaciers, deposited several tens to hundreds of millions of years ago during periods of high spin-axis obliquity. Previous workers have argued that the Smooth Facies in the FSD contains a core of ancient glacial ice. Here, we find evidence that additional glacial ice remains preserved within several other landforms in the Smooth Facies and Ridged Facies. These include landforms that we interpret as kame and kettle topography on the basis of their distribution, size, and morphologies ranging progressively from knobs to degraded knobs to pits. We argue that some moraines in the Ridged Facies are icecored on the basis of their interactions with lava flows and the axial troughs at the crests of some moraines. We also argue that dunes with axial troughs, found in and surrounding the FSD, are the remnants of sediment-covered snow dunes formed by reworking of snow or glacial ice, and that the axial troughs form as tension cracks in the sediment and deepen by sublimation of the underlying ice. Longt e rm preservation of water ice in equatorial environments is assisted by a meters- to decameters-thick debris cover (lag) formed from sublimation of dirty ice, as well as burial beneath volcanic tephra and aeolian deposits. This ancient ice could contain preserved biosignatures, provide information on Martian climate and atmospheric history, and serve as a resource for human exploration.
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volcano ice interactions in the arsia mons tropical Mountain Glacier deposits
Icarus, 2014Co-Authors: Kathleen E. Scanlon, James W. Head, Lionel Wilson, David R. MarchantAbstract:Fan-shaped deposits (FSD) superposed on the sides of the Tharsis Montes volcanic edifices are widely interpreted to have been formed by cold-based glaciation during the Late Amazonian, a period when the Tharsis Montes were volcanically active. We survey the similar to 166,000 km(2) Arsia Mons FSD using new, high-resolution image and topography data and describe numerous landforms indicative of volcano-ice interactions. These include (1) steep-sided mounds, morphologically similar to terrestrial tindar that form by subglacial eruptions under low confining pressure; (2) steep-sided, leveed flow-like landforms with depressed centers, interpreted to be subglacial lava flows with chilled margins; (3) digitate flows that we interpret as having resulted from lava flow interaction with glacial ice at the upslope margin of the Glacier; (4) a plateau with the steep sides and smooth capping flow of a basaltic tuya, a class of feature formed when subglacial eruptions persist long enough to melt through the overlying ice; and (5) low, areally extensive mounds that we interpret as effusions of pillow lava, formed by subglacial eruptions under high confining pressure. Together, these eruptions involved hundreds of cubic kilometers of subglacially erupted lava; thermodynamic relationships indicate that this amount of lava would have produced a similar volume of subglacial liquid meltwater, some of which carved fluvial features in the FSD. Landforms in the FSD also suggest that glaciovolcanic heat transfer induced local wet-based flow in some parts of the Glacier. Glaciovolcanic environments are important microbial habitats on Earth, and the evidence for widespread liquid water in the Amazonian-aged Arsia Mons FSD makes it one of the most recent potentially habitable environments on Mars. Such environments could have provided refugia for any life that developed on Mars and survived on its surface until the Amazonian.
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Preservation of Ancient Ice in Tropical Mountain Glacier Deposits on Mars
2008Co-Authors: James W. Head, David R. MarchantAbstract:Introduction: Analysis new data for the extensive fanshaped deposits on the NW flanks of the equatorial Tharsis Montes (Fig. 1) provides compelling evidence that they represent the remnants of tropical Mountain Glaciers (TMG) dating from the Late Amazonian [1-5]. The distinct geomorphology of the deposits, together with updated terrestrial analogs for glaciation under martian hyper-arid, extremely cold conditions [6], show that the tropical Mountain Glaciers were cold-based. Global climate models show that when obliquity reaches 45 degrees, water-rich air ascends the flanks of Tharsis, encounters the NW flanks of the Tharsis volcanoes, undergoes upwelling and adiabatic cooling, precipitating snow on the northwest flanks [7]. Models of accumulation and glacial flow show that this scenario can produce tropical Mountain Glaciers [8]. On Earth, when Glaciers retreat, ablation can result in an increase of debris on top of the Glacier (sublimation till); this deposit can significantly decrease the sublimation rate and protect the buried ice from further loss of ice, preserving it for long periods [9-10]; in the Antarctic Dry Valleys, ice buried below sublimation till may be as old as 8 million years [11]. Is there any evidence of similar remnant ice in the tropical Mountain Glaciers on Mars? Description and interpretation: Arsia and Pavonis TMG deposits (Fig. 1) consist of three basic facies, ridged (R), knobby (K) and smooth (S) [1-5]. The proximal smooth facies consists of lobate, relatively smooth-textured deposits interpreted as the remnants of individual cold-based glacial lobes (alpine-like Glaciers), emplaced in the waning stages of glaciation [3]. Debris-covered cold-based Glaciers build up a protective sublimation till derived from supraglacial and englacial debris. As glacial conditions wane, ice is often preserved longest in the distal portions, where the insulating effect of the till is greatest, producing thick arcuate lobes. Similar arcuate lobe configurations are seen at Arsia and Pavonis (Fig. 1). Could these lobes, morphologically and environmentally similar to those seen on Earth, still contain remnant glacial ice from the Late Amazonian glaciation [10] many tens of millions of years ago? Analysis of high-resolution image and altimetry data reveal several crater-like depressions in the smooth facies at Arsia (Fig. 2) and Pavonis (Fig 3). These features are shallower than fresh impact craters of similar diameters and show significant evidence of having undergone viscous relaxation. They have several zones (Figs. 2-3): An inner hummocky, but often oyster-shell-like floor with outward-facing scarps; an intermediate zone beyond the apparent crater rim of concentric ridges and troughs; a narrow zone of closely-spaced fractures; and an outer zone of hummocks oriented along the regional trend of the lobe, sometimes with superposed secondary craters (Fig. 2c, d). These resemble (Fig. 3d) viscously relaxed craters in laboratory experiments [12]. The sequence of evolution visualized for these craters is shown in Fig. 4. In summary, TMG deposits on Mars record ancient climates when planetary spin-axis obliquity was in excess of 45°, and polar volatiles were mobilized and transferred equatorward. We interpret the set of unusual impact craters superposed on these deposits (Figs. 2-3) to indicate that the impact penetrated a veneer of sublimation till and excavated buried remnant glacial ice, subsequently undergoing viscous relaxation. Remaining deposits may be hundreds of meters thick. The deposits are Late Amazonian in age and the remnant ice may preserve records of ancient atmospheric gas content and microbiota, as is seen in terrestrial glacial ice [13]. References: 1) J. Head and D. Marchant, Geology, 31, 641, 2003; 2) D. Shean et al., JGR, 110, 05001, 2005; 3) D. Shean et al., JGR, 112, E03004, 2007; 4) S. Milkovich et al., Icarus, 181, 388, 2006; 5) S. Kadish et al., Icarus, in revision, 2007; 6) D. Marchant and J. Head, Icarus, 192, 187, 2007; 7) F. Forget, et al.. Science, 311, 368, 2006; 8) J. Fastook et al., LPSC 37, #1794, 2006; 9) D. Kowalewski et al., Ant. Sci., 18, 421, 2006; 10) J. Helbert et al, LPSC 37, #1371, 2006; 11) D. Marchant et al., ISAES, 54, 2007; 12) R. Scott (1967) Icarus, 7, 139. 13) K. Bidle et al., PNAS, 104, 13455, 2007; 14) A. Kress and J. Head, LPSC 39, #1273, 2008; 15) A. Kress et al., LPSC 39, #1293, 2008.
Tianjin Huang - One of the best experts on this subject based on the ideXlab platform.
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A new method to estimate changes in Glacier surface elevation based on polynomial fitting of sparse ICESat—GLAS footprints
Sensors, 2017Co-Authors: Tianjin Huang, Massimo Menenti, Jing Lu, Li Jia, Jie Zhou, Guangcheng HuAbstract:We present in this paper a polynomial fitting method applicable to segments of footprints measured by the Geoscience Laser Altimeter System (GLAS) to estimate Glacier thickness change. Our modification makes the method applicable to complex topography, such as a large Mountain Glacier. After a full analysis of the planar fitting method to characterize errors of estimates due to complex topography, we developed an improved fitting method by adjusting a binary polynomial surface to local topography. The improved method and the planar fitting method were tested on the accumulation areas of the Naimona’nyi Glacier and Yanong Glacier on along-track facets with lengths of 1000 m, 1500 m, 2000 m, and 2500 m, respectively. The results show that the improved method gives more reliable estimates of changes in elevation than planar fitting. The improved method was also tested on Guliya Glacier with a large and relatively flat area and the Chasku Muba Glacier with very complex topography. The results in these test sites demonstrate that the improved method can give estimates of Glacier thickness change on Glaciers with a large area and a complex topography. Additionally, the improved method based on GLAS Data and Shuttle Radar Topography Mission-Digital Elevation Model (SRTM-DEM) can give estimates of Glacier thickness change from 2000 to 2008/2009, since it takes the 2000 SRTM-DEM as a reference, which is a longer period than 2004 to 2008/2009, when using the GLAS data only and the planar fitting method.
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a new method to estimate changes in Glacier surface elevation based on polynomial fitting of sparse icesat glas footprints
Sensors, 2017Co-Authors: Tianjin Huang, Massimo Menenti, Li Jia, Jie ZhouAbstract:We present in this paper a polynomial fitting method applicable to segments of footprints measured by the Geoscience Laser Altimeter System (GLAS) to estimate Glacier thickness change. Our modification makes the method applicable to complex topography, such as a large Mountain Glacier. After a full analysis of the planar fitting method to characterize errors of estimates due to complex topography, we developed an improved fitting method by adjusting a binary polynomial surface to local topography. The improved method and the planar fitting method were tested on the accumulation areas of the Naimona’nyi Glacier and Yanong Glacier on along-track facets with lengths of 1000 m, 1500 m, 2000 m, and 2500 m, respectively. The results show that the improved method gives more reliable estimates of changes in elevation than planar fitting. The improved method was also tested on Guliya Glacier with a large and relatively flat area and the Chasku Muba Glacier with very complex topography. The results in these test sites demonstrate that the improved method can give estimates of Glacier thickness change on Glaciers with a large area and a complex topography. Additionally, the improved method based on GLAS Data and Shuttle Radar Topography Mission-Digital Elevation Model (SRTM-DEM) can give estimates of Glacier thickness change from 2000 to 2008/2009, since it takes the 2000 SRTM-DEM as a reference, which is a longer period than 2004 to 2008/2009, when using the GLAS data only and the planar fitting method.
Xi Jiang - One of the best experts on this subject based on the ideXlab platform.
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estimating Mountain Glacier surface temperatures from landsat etm thermal infrared data a case study of qiyi Glacier china
Remote Sensing of Environment, 2015Co-Authors: Ninglian Wang, Xi JiangAbstract:Abstract Surface temperatures on Mountain Glaciers are a direct reflection of the heat budget at the Glacier surface, which controls the degree of ablation. An understanding of surface temperatures is therefore crucial in simulating the evolution of Mountain Glaciers and in understanding a Glacier's response to climate change. In situ observations indicate that when the exitance angle equals 75°, relative to the nadir angle, the emissivity variation at λ = 12.5 μm in bare ice is as much as 0.24. However, research involving the remote-sensing-retrieval of Mountain Glacier surface temperatures does not generally take into account the topography (i.e., the exitance angle), and the validation of remote sensing approaches using surficial climate measurements on Mountain Glaciers is lacking. Here we utilize the ETM + multispectral dataset and resampled water vapor content data from MOD05, combined with the emissivity model of ice and snow, taking the exitance angle into account (Hori et al., 2013), and employ the single-channel algorithm developed by Jimenez-Munoz et al. (2009), to calculate the remote-sensing-retrieved surface temperature distribution across Qiyi Glacier, China, from July 2012 to September 2013. The remote-sensing-retrieved temperatures are validated by the 10-min mean measurements of surface temperature from two automatic weather stations at different altitudes on the Glacier, and the results show good agreement at the two sites, with an average bias of 0.96 K and an average root mean square error of 1.5 K. Of note, in summer the influence of thermal emissions from surrounding topography means that the error associated with retrieved temperatures for the Glacier tongue and margins might exceed 1.5 K.
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Estimating Mountain Glacier surface temperatures from Landsat-ETM + thermal infrared data: A case study of Qiyi Glacier, China
Remote Sensing of Environment, 2015Co-Authors: Ninglian Wang, Xi JiangAbstract:Abstract Surface temperatures on Mountain Glaciers are a direct reflection of the heat budget at the Glacier surface, which controls the degree of ablation. An understanding of surface temperatures is therefore crucial in simulating the evolution of Mountain Glaciers and in understanding a Glacier's response to climate change. In situ observations indicate that when the exitance angle equals 75°, relative to the nadir angle, the emissivity variation at λ = 12.5 μm in bare ice is as much as 0.24. However, research involving the remote-sensing-retrieval of Mountain Glacier surface temperatures does not generally take into account the topography (i.e., the exitance angle), and the validation of remote sensing approaches using surficial climate measurements on Mountain Glaciers is lacking. Here we utilize the ETM + multispectral dataset and resampled water vapor content data from MOD05, combined with the emissivity model of ice and snow, taking the exitance angle into account (Hori et al., 2013), and employ the single-channel algorithm developed by Jimenez-Munoz et al. (2009), to calculate the remote-sensing-retrieved surface temperature distribution across Qiyi Glacier, China, from July 2012 to September 2013. The remote-sensing-retrieved temperatures are validated by the 10-min mean measurements of surface temperature from two automatic weather stations at different altitudes on the Glacier, and the results show good agreement at the two sites, with an average bias of 0.96 K and an average root mean square error of 1.5 K. Of note, in summer the influence of thermal emissions from surrounding topography means that the error associated with retrieved temperatures for the Glacier tongue and margins might exceed 1.5 K.
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a distributed surface energy and mass balance model and its application to a Mountain Glacier in china
Chinese Science Bulletin, 2010Co-Authors: Ninglian Wang, Xi Jiang, Gaoju SongAbstract:Based on the field observations on Qiyi Glacier during the warm season of 2007, using a digital elevation model (DEM, 15 m resolution), we developed a distributed surface energy- and mass-balance model with an hourly resolution. The model described the effect of topography on shortwave solar radiation, and used a new parameterization for Glacier albedo. The model was applied to Qiyi Glacier in the Qilian Mountain, China, for the period 20: 00 30 June to 12: 00 10 October 2007, to simulate the firn-line changes, the temporal and spatial variations of mass balance, and the glacial meltwater runoff. The results indicated that the patterns of altitudinal profile of Glacier mass-balance were affected mainly by the altitudinal profile of albedo, and the status of the Glacier mass balance was influenced directly by the values of albedo. The parameter sensitivity test showed that the model was sensitive to the air temperature lapse rate and precipitation gradient, and also sensitive to the threshold temperature for solid/liquid precipitation. Furthermore, the climate sensitivity test showed that the mass balance was more sensitive to air temperature than precipitation, and the response of mass balance to air temperature change was nonlinear while the response to precipitation change linearly. The negative mass balance trend of the Glacier can not be reversed when precipitation increases by 20% and meanwhile air temperature rises by 1°C.
D R Marchant - One of the best experts on this subject based on the ideXlab platform.
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volcanism induced local wet based glacial conditions recorded in the late amazonian arsia mons tropical Mountain Glacier deposits
Icarus, 2015Co-Authors: K E Scanlon, J W Head, D R MarchantAbstract:Abstract The tropical Mountain glacial fan-shaped deposit (FSD) to the northwest of the Arsia Mons volcano on Mars contains numerous glacial and volcanic landforms. While most of the glacial landforms are interpreted to have formed by cold-based glacial processes, several glacial landforms near glaciovolcanic edifices are more consistent with localized wet-based glacial processes. These landforms include ribbed moraines, which suggest local, thermal transitions between wet- and cold-based ice; thrust-block moraines, whose formation is typically assisted by the presence of subglacial water; streamlined knobs that we interpret to have been sculpted by ice sliding along its base; and a braided outflow channel. The presence and association of these features, together with evidence of both subglacial volcanic eruptions and local ice-marginal advances, favor polythermal Glaciers with localized wet-based conditions. We propose that lava-to-ice heat transfer during the eruption of the glaciovolcanic edifices caused the Arsia Mons paleoGlacier to melt at its base in some areas, resulting in these locally wet-based glacial conditions. A polythermal Glacier provides more potential microbial habitats and more connectivity between habitats than does a cold-based Glacier, and we review glacial and glaciovolcanic habitats on Earth that may provide insight into the likelihood of potential microbial habitats within the Arsia Mons FSD on Mars.
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origin and evolution of a cold based tropical Mountain Glacier on mars the pavonis mons fan shaped deposit
Journal of Geophysical Research, 2005Co-Authors: David E Shean, J W Head, D R MarchantAbstract:[1] Each of the large Tharsis Montes volcanoes in the equatorial region of Mars has an unusual Amazonian-aged fan-shaped deposit on its west-northwestern flank. On the basis of Viking Orbiter data, the origin of these deposits has been variously ascribed to volcanic, mass-wasting, tectonic, and glacial processes. Using new MGS and Odyssey data, combined with recent developments in the study of cold-based Glaciers, we reassess the geology and mode of origin for these deposits with particular emphasis on Pavonis Mons. The deposits share three characteristic facies, including (1) a ridged facies, consisting of tens to >100 parallel, concentric ridges around the margins of the deposits, (2) a knobby facies composed of irregular hills and hummocks, and (3) a smooth facies of broad, lobate plains that superposes all other units within the deposits. On the basis of morphology, topography, superposition relationships, and close terrestrial analogs in the Dry Valleys of Antarctica, we interpret the Pavonis fan-shaped deposit as the depositional remains of a cold-based Glacier that formed on the northwestern flank in recent Martian history. We interpret the ridged facies as drop moraines formed around the margins of a retreating cold-based Glacier, the knobby facies as a sublimation till derived from in situ down-wasting of cold-based glacial ice, and the smooth facies as extant debris-covered glacial ice. In addition to the three main facies, the fan-shaped deposit at Pavonis Mons contains several unique features, including arcuate scarps, high-relief flow-like features, and radial ridges, which suggest that volcanism played a role during its formation. Using recent results from Mars general circulation model simulations, we outline a model of Glacier formation involving atmospheric deposition of water ice on the northwestern flanks of the Tharsis Montes during periods of high mean obliquity. Reconstructed ice sheet profiles for each of the Tharsis Montes Glaciers suggest that the ice sheets attained average thicknesses of ∼1.6–2.4 km, values that are consistent with a cold-based glacial origin. Analysis of crater size-frequency distributions using new data indicates that the age of the glaciation lies within the Late Amazonian (∼10–200 Ma). Thus our results suggest that multiple phases of tropical Mountain glaciation occurred on Mars within the past few hundred Myr and that significant amounts of near-surface, equatorial ice may remain within the deposit today.