Software tools for GNSS interferometric reflectometry (GNSS-IR)     

Carolyn Roesler  Kristine M. Larson 《GPS Solutions》2018,22(3):80

GNSS-R interferometric reflectometry (also known as GNSS-IR, or GPS-IR for GPS signals) is a technique that uses data from geodetic-quality GNSS instruments for sensing the near-field environment. In contrast to positioning, atmospheric, and timing applications of GNSS, GNSS-IR uses the signal-to-noise ratio (SNR) data. Software is provided to translate GNSS files, map GNSS-IR reflection zones, calculate GNSS-IR Nyquist frequencies, and estimate changes in the height of a reflecting surface from GNSS SNR data.  相似文献   

Dating very young planetary surfaces from crater statistics: A review of issues and challenges          下载免费PDF全文

Jean-Pierre Williams  Carolyn H. van der Bogert  Asmin V. Pathare  Gregory G. Michael  Michelle R. Kirchoff  Harald Hiesinger 《Meteoritics & planetary science》2018,53(4):554-582

Determining the ages of young planetary surfaces relies on using populations of small, often sub-km diameter impact craters due to the higher frequency at which they form. Smaller craters however can be less reliable for estimating ages as their size-frequency distribution is more susceptible to alteration with debate as to whether they should be used at all. With the current plethora of meter-scale resolution images acquired of the lunar and Martian surfaces, small craters have been widely used to derive model ages to establish the temporal relation of recent geologic events. In this review paper, we discuss the many factors that make smaller craters particularly challenging to use and should be taken into consideration when crater counts are confined to small crater diameters. Establishing confidence in a model age ultimately requires an understanding of the geologic context of the surface being dated as reliability can vary considerably and limitations of the dating technique should be considered in applying ages to any geologic interpretation.  相似文献   

Recreating Ocean Space: Recreational Consumption and Representation of the Caribbean Marine Environment     

Carolyn Trist 《The Professional geographer》1999,51(3):376-387

This paper investigates the historical relationship between the development of marine-based tourism and representations of marine space. Over the past 100 years, the Caribbean Sea has been transformed from a transportation surface connecting exotic ports of call into a commodity itself. Imagined by early travelers as a two-dimensional space to be crossed, the Caribbean has became part of a new tropical marine aesthetic, a three-dimensional spectacle to be actively consumed and conserved. These changing representations of the marine environment as a space of consumption have been paralleled by changes in the relationships between marine and terrestrial political economies. As marine-based tourism has intensified, the balance of power among coastal resource users has shifted. The increasingly conflictive consequences of this shift are illustrated by the case of Soufrière in St. Lucia where new uses of marine space have re-configured social and economic relationships. Soufrière's coastal economy has been transformed and its marine space increasingly politicized as competing representations of the sea have been used to assert conflicting claims to resource access. This paper attempts to elucidate the power of these representations by investigating their historical relationship to the changing role of the Caribbean Sea in the international tourism industry.  相似文献   

The transition from complex crater to peak-ring basin on Mercury: New observations from MESSENGER flyby data and constraints on basin formation models     

David M.H. Baker  James W. Head  Samuel C. Schon  Carolyn M. Ernst  Louise M. Prockter  Scott L. Murchie  Brett W. Denevi  Sean C. Solomon  Robert G. Strom 《Planetary and Space Science》2011,59(15):1932-1948

The study of peak-ring basins and other impact crater morphologies transitional between complex craters and multi-ring basins is important to our understanding of the mechanisms for basin formation on the terrestrial planets. Mercury has the largest population, and the largest population per area, of peak-ring basins and protobasins in the inner solar system and thus provides important data for examining questions surrounding peak-ring basin formation. New flyby images from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have more than doubled the area of Mercury viewed at close range, providing nearly complete global coverage of the planet's surface when combined with flyby data from Mariner 10. We use this new near-global dataset to compile a catalog of peak-ring basins and protobasins on Mercury, including measurements of the diameters of the basin rim crest, interior ring, and central peak (if present). Our catalog increases the population of peak-ring basins by ∼150% and protobasins by ∼100% over previous catalogs, including 44 newly identified peak-ring basins (total=74) and 17 newly identified protobasins (total=32). A newly defined transitional basin type, the ringed peak-cluster basin (total=9), is also described. The new basin catalog confirms that Mercury has the largest population of peak-ring basins of the terrestrial planets and also places the onset rim-crest diameter for peak-ring basins at , which is intermediate between the onset diameter for peak-ring basins on the Moon and those for the other terrestrial planets. The ratios of ring diameter to rim-crest diameter further emphasize that protobasins and peak-ring basins are parts of a continuum of basin morphologies relating to their processes of formation, in contrast to previous views that these forms are distinct. Comparisons of the predictions of peak-ring basin-formation models with the characteristics of the basin catalog for Mercury suggest that formation and modification of an interior melt cavity and nonlinear scaling of impact melt volume with crater diameter provide important controls on the development of peak rings. The relationship between impact-melt production and peak-ring formation is strengthened further by agreement between power laws fit to ratios of ring diameter to rim-crest diameter for peak-ring basins and protobasins and the power-law relation between the dimension of a melt cavity and the crater diameter. More detailed examination of Mercury's peak-ring basins awaits the planned insertion of the MESSENGER spacecraft into orbit about Mercury in 2011.  相似文献   

Sexual and other differences in Copepodite stages of some New Zealand Calamoecia and Boeckella SPP. (Copepoda: Calanoida)     

M. Ann Chapman  Carolyn W. Burns 《新西兰海洋与淡水研究杂志》2013,47(1):131-137

Differences between males and females in the morphology of the fifth legs were found in stage IV copepodites of Boeckella hamata and in stage V cope‐podites of B. hamata, B. propinqua, B. dilatata, B. triarticulata, and Calamoecia lucasi. There were also sexual differences in overall body size. In B. hamata, B. triarticulata, and B. dilatata, the differences were sufficiently obvious for stage V copepodites to be sexed at low magnifications. The diagnostic features of all stages are described.  相似文献   

New records of distribution and co‐occurrence of freshwater calanoid copepods in New Zealand (note)     

Carolyn W. Burns 《新西兰海洋与淡水研究杂志》2013,47(1):149-150

Calamoecia lucasi was found with Boeckella propinqua in the Kaihoka Lakes, Nelson, and Boeckella hamata with Boeckella triarticulata in Lake Elterwater, Marlborough. These are the first records of C. lucasi in the South Island, New Zealand, and of B. hamata co‐occurring with B. triarticulata.  相似文献   

Population Genetic Structure of the New Zealand Estuarine Clam <Emphasis Type="Italic">Austrovenus stutchburyi</Emphasis> (Bivalvia: Veneridae) Reveals Population Subdivision and Partial Congruence with Biogeographic Boundaries     

Philip M. Ross  Ian D. Hogg  Conrad A. Pilditch  Carolyn J. Lundquist  Richard J. Wilkins 《Estuaries and Coasts》2012,35(1):143-154

We examined the population genetic structure of the New Zealand endemic clam, Austrovenus stutchburyi, to determine (1) whether populations of this estuarine taxon are genetically subdivided and (2) if the locations of genetic boundaries were congruent with known biogeographic break points. We obtained sequences of the mitochondrial gene cytochrome c oxidase I for 372 A. stutchburyi from 29 New Zealand estuaries and conducted analyses to identify population genetic structure. We detected a pattern of genetic isolation by distance and identified six A. stutchburyi subpopulations, a greater number of subpopulations than reported for much of New Zealand’s open coast benthos. Although these data indicate that long distance dispersal may be less frequent in estuarine than in open coast taxa, partial congruence between genetic and biogeographic boundaries suggests that historical events and natural selection may also contribute to the observed population genetic structure.  相似文献   

Mapping the physiography of Michigan with GIS     

Randall J. Schaetzl  Helen Enander  Michael D. Luehmann  David P. Lusch  Carolyn Fish  Michael Bigsby 《自然地理学》2013,34(1):2-39

Abstract

We present a new physiographic map of Michigan, that is also available interactively, online. Only four, small-scale physiographic maps of Michigan had been previously published. Our mapping project made use of a wide variety of spatial data, in a GIS environment, to visualize and delineate the physical landscape in more detail than has been done previously. We also examined many of the unit boundaries in the field, using a GIS running on a GPS-enabled laptop. Unlike previous physiographic maps, the online version of the map enables users to query the criteria used to define each of the 224 boundaries of its 10 major and 91 minor physiographic units. The interactive nature of the online version of the map is a unique enhancement to physiographic maps and mapping. Our study also provides data on the number and types of criteria used to define each of the 224 unit boundaries within the map. Most of our unit boundaries are based on data derived from 10-m raster elevation data and NRCS soils data, e.g., relief, soil wetness, escarpments, landscape fabric, and parent material characteristics. Data gleaned from NRCS SSURGO county-scale soil maps were a strength of the project. [Key words: Michigan, physiography, landforms, soils, GIS, mapping]  相似文献   

The Death and Life of Main Street: Small Towns in American Memory,Space, and Community     

Carolyn Adams 《Geographical review》2014,104(3):376-379

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Managing shoreline retreat: a US perspective     

Carolyn Kousky 《Climatic change》2014,124(1-2):9-20

As sea level rises, coastal communities will face increased risks of flooding, storm surge, and inundation. In some areas, structural protective measures will be built, and for some properties, accommodation to sea level rise may be possible. For other areas, however, some form of retreat will be either preferred on economic or sociopolitical grounds or required given fiscal constraints. This paper considers how society can proactively manage shoreline retreat in those locations where it is deemed the preferable policy. A three-part strategy is proposed: (1) reduce new development in the highest-risk areas; (2) adopt policies that allow for expected and orderly removal or modification of development as inundation occurs; and (3) take advantage of disasters to implement managed retreat approaches. Specific policies are recommended and the challenges of institutional change discussed.  相似文献