A Truly Spatial Random Forests Algorithm for Geoscience Data Analysis and Modelling     

Talebi  Hassan  Peeters  Luk J. M.  Otto  Alex  Tolosana-Delgado  Raimon 《Mathematical Geosciences》2022,54(1):1-22

Mathematical Geosciences - Spatial data mining helps to find hidden but potentially informative patterns from large and high-dimensional geoscience data. Non-spatial learners generally look at the...  相似文献   

The Meteoritical Bulletin,No. 101          下载免费PDF全文

Alex Ruzicka  Jeffrey Grossman  Audrey Bouvier  Christopher D. K. Herd  Carl B. Agee 《Meteoritics & planetary science》2015,50(9):1661-1661

Meteoritical Bulletin 101 contains 2639 meteorites accepted by the Nomenclature Committee in 2012, including 1 fall (Battle Mountain), with 2308 ordinary chondrites, 156 carbonaceous chondrites, 63 HED achondrites, 17 relict meteorites, 16 Rumuruti chondrites, 15 enstatite chondrites, 15 ureilites, 10 iron meteorites, 9 lunar meteorites, 9 primitive achondrites, 8 ungrouped achondrites, 7 mesosiderites, 4 Martian meteorites, and 2 Pallasites, and with 1812 from Antarctica, 437 from Asia, 301 from Africa, 43 from South America, 21 from Europe (including Russia), 21 from North America, 3 from Oceania, and 1 from unknown. Information about approved meteorites can be obtained from the Meteoritical Bulletin Database (MBD) available on line at http://www.lpi.usra.edu/meteor/ .  相似文献   

Ecosystem objectives to support the UK vision for the marine environment     

Rogers SI  Tasker ML  Earll R  Gubbay S 《Marine pollution bulletin》2007,54(2):128-144

European Maritime States already have commitments to protect species and habitats and maintain quality standards in coastal and offshore waters. These are a direct response to environmental legislation in Europe and commitments made to biodiversity conservation in OSPAR and at the World Summit on Sustainable Development. An integrated approach to management requires that these are consistent with the requirements for sustainable development, and include wider social considerations and active stakeholder participation. This review describes a hierarchical framework that incorporates the marine objectives and delivery statements of ecological, social and economic sectors. The framework leads from the UK's guiding principles for sustainable development, through visionary statements and strategic goals for high level delivery, to operational objectives and statements of action which deliver management. Parts of this hierarchy can already be populated for the UK, especially those at the higher levels. At the operational level, however, there is less clarity. The review shows that, despite some gaps, existing commitments for ecological components of the ecosystem are transparent and generally conform to this framework, due largely to high profile government funding of environmental protection and science and a single national vision for the marine environment. Specific objectives for six components of the ecosystem were developed; benthic habitats, seabirds and mammals, phytoplankton and zooplankton, fish, and physical/chemical quality of the water and atmosphere. The objectives included some that avoided limits and others that aimed to achieve targets, and for management to be effective it will be important to have a common understanding of how these can together be interpreted and made operational. In a review of 13 social and economic sectors, few provided a clear breakdown of objectives leading from a high level vision or a sustainable development principle. Six sectors did not have high level government targets for production or other measures of sectoral performance. Such commercial operations generally determine their own operational delivery targets based on market forces. Recent proposals in Europe to create an integrated framework for social, economic and environmental activities will need to carefully balance the development of a strong and competitive marine economy with existing international obligations to environmental protection.  相似文献   

Characterization of a hypoxia-responsive leptin receptor (omLepR(L)) cDNA from the marine medaka (Oryzias melastigma)     

Wong MM  Yu RM  Ng PK  Law SH  Tsang AK  Kong RY 《Marine pollution bulletin》2007,54(6):797-803

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Vertical circulation in shallow tidal inlets and back-barrier basins     

Emil V. Stanev  Burghard W. Flemming  Alex Bartholomä  Joanna V. Staneva  Jörg-Olaf Wolff 《Continental Shelf Research》2007

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Donald V. Helmberger,the master mentor: Testimonials from former international students          下载免费PDF全文

Xiaodong Song  Sidao Ni  Ying Tan  Alex Song  Risheng Chu  Daoyuan Sun  Shengji Wei  Semechah Lui  Voon Hui Lai 《地震科学（英文版）》2022,35(1):67-70

Don trained many Ph.D.students over the～5 decades of his career,at least 45 were advised or co-advised according to a Caltech account.A large number were intern...  相似文献   

Determining Titan surface topography from Cassini SAR data     

Bryan W. Stiles  Scott Hensley  David M. Bates  Alex Hayes  Ralph D. Lorenz  Philip S. Callahan  William T.K. Johnson  Jonathan I. Lunine  Michael Janssen  Richard D. West  the Cassini RADAR Team 《Icarus》2009,202(2):584-598

A technique, referred to as SARTopo, has been developed for obtaining surface height estimates with 10 km horizontal resolution and 75 m vertical resolution of the surface of Titan along each Cassini Synthetic Aperture Radar (SAR) swath. We describe the technique and present maps of the co-located data sets. A global map and regional maps of Xanadu and the northern hemisphere hydrocarbon lakes district are included in the results. A strength of the technique is that it provides topographic information co-located with SAR imagery. Having a topographic context vastly improves the interpretability of the SAR imagery and is essential for understanding Titan.SARTopo is capable of estimating surface heights for most of the SAR-imaged surface of Titan. Currently nearly 30% of the surface is within 100 km of a SARTopo height profile. Other competing techniques provide orders of magnitude less coverage.We validate the SARTopo technique through comparison with known geomorphological features such as mountain ranges and craters, and by comparison with co-located nadir altimetry, including a 3000 km strip that had been observed by SAR a month earlier. In this area, the SARTopo and nadir altimetry data sets are co-located tightly (within 5-10 km for one 500 km section), have similar resolution, and as expected agree closely in surface height. Furthermore the region contains prominent high spatial resolution topography, so it provides an excellent test of the resolution and precision of both techniques.  相似文献   

Geologic context of in situ rocky exposures in Mare Serpentis, Mars: Implications for crust and regolith evolution in the cratered highlands     

A.D. Rogers  O. Aharonson  J.L. Bandfield 《Icarus》2009,200(2):446-462

Global acquisition of infrared spectra and high-resolution visible and infrared imagery has enabled the placement of compositional information within stratigraphic and geologic context. Mare Serpentis, a low albedo region located northwest of Hellas Basin, is rich in spectral and thermophysical diversity and host to numerous isolated exposures of in situ rocky material. Most martian surfaces are dominated by fine-grained particulate materials that bear an uncertain compositional and spatial relationship to their source. Thus location and characterization of in situ rock exposures is important for understanding the origin of highland materials and the processes which have modified those materials. Using spectral, thermophysical and morphologic information, we assess the local and regional stratigraphy of the Mare Serpentis surface in an effort to reconstruct the geologic history of the region. The martian highlands in Mare Serpentis are dominated by two interspersed surface units, which have distinct compositional and thermophysical properties: (1) rock-dominated surfaces relatively enriched in olivine and pyroxene, and depleted in high-silica phases, and (2) sediment or indurated material depleted in olivine and pyroxene, with relatively higher abundance of high-silica phases. This is a major, previously unrecognized trend which appears to be pervasive in the Mare Serpentis region and possibly in other highland areas. The detailed observations have led us to form two hypotheses for the relationship between these two units: either (1) they are related through a widespread mechanical and/or chemical alteration process, where less-mafic plains materials are derived from the mafic bedrock, but have been compositionally altered in the process of regolith formation, or (2) they are stratigraphically distinct units representing separate episodes of upper crust formation. Existing observations suggest that the second scenario is more likely. In this scenario, plains materials represent older, degraded, and possibly altered, “basement” rock, whereas the rocky exposures represent later additions to the crust and are probably volcanic in origin. These hypotheses should be further testable with decimeter-resolution imagery and meter-resolution short wavelength infrared spectra.  相似文献   

Mineralogical characterization of Mars Science Laboratory candidate landing sites from THEMIS and TES data     

A. Deanne Rogers  Joshua L. Bandfield 《Icarus》2009,203(2):437-453

Data from the Mars Global Surveyor Thermal Emission Spectrometer (TES) and the Mars Odyssey Thermal Emission Imaging System (THEMIS) instruments are used to assess the mineralogic and dust cover characteristics of landing regions proposed for the Mars Science Laboratory (MSL) mission. Candidate regions examined in this study are Eberswalde crater, Gale crater, Holden crater, Mawrth Vallis, Miyamoto crater, Nili Fossae Trough, and south Meridiani Planum. Compositional units identified in each region from TES and THEMIS data are distinguished by variations in hematite, olivine, pyroxene and high-silica phase abundance, whereas no units are distinguished by elevated phyllosilicate or sulfate abundance. Though phyllosilicate minerals have been identified in all sites using near-infrared observations, these minerals are not unambiguously detected using either TES spectral index or deconvolution analysis methods. For some of the sites, small phyllosilicate outcrop sizes relative to the TES field of view likely hinder phyllosilicate mineral detection. Porous texture and/or small particle size (<∼60 μm) associated with the phyllosilicate-bearing surfaces may also contribute to non-detections in the thermal infrared data sets, in some areas. However, in Mawrth Vallis and Nili Fossae, low phyllosilicate abundance (<10-20 areal %, depending on the phyllosilicate composition) is the most likely explanation for non-detection. TES data over Mawrth Vallis indicate that phyllosilicate-bearing surfaces also contain significant concentrations (>15%, possibly up to ∼40%) of a high-silica phase such as amorphous silica or zeolite. High-silica phase abundance over phyllosilicate-bearing surfaces in Mawrth Vallis is higher than that of surrounding surfaces by 10-15%. With the exception of these high-silica surfaces in Mawrth Vallis, regions examined in this study exhibit similar bulk mineralogical compositions to that of most low-albedo regions on Mars; the MSL scientific payload will thus be able to provide important information on surface materials typical of low-albedo regions in addition to investigating the origin of phyllosilicate and/or sulfate deposits. With the exception of Gale crater, all of the landing sites have relatively low dust cover compared to classic high-albedo regions (Tharsis, Arabia and Elysium) and to previous landing sites in Gusev Crater, Utopia Planitia, and Chryse Planitia.  相似文献   

High Temporal and Spectral Resolution Interferometric Observations of Unusual Solar Radio Bursts     

D. Oberoi  E. R. Evarts  A. E. E. Rogers 《Solar physics》2009,260(2):389-400

We report very high temporal and spectral resolution interferometric observations of some unusual solar radio bursts near 1420 MHz. These bursts were observed on 13 September 2005, 22 minutes after the peak of a GOES class X flare from the NOAA region 10808. Our observations show 11 episodes of narrow-band intermittent emission within a span of ≈ 8 s. Each episode shows a heavily frequency-modulated band of emission with a spectral slope of about −245.5 MHz s⁻¹, comprising up to 8 individual blobs of emission and lasts for 10 – 15 ms. The blobs themselves have a spectral slope of ≈ 0 MHz s⁻¹, are ≈ 200 – 250 kHz wide, appear every ≈ 400 kHz and last for ≈ 4 – 5 ms. These bursts show brightness temperatures in the range 10¹² K, which suggests a coherent emission mechanism. We believe these are the first high temporal and spectral resolution interferometric observations of such rapid and narrow-bandwidth solar bursts close to 1420 MHz and present an analysis of their temporal and spectral characteristics.  相似文献