The Experts below are selected from a list of 25902 Experts worldwide ranked by ideXlab platform
Brendan J Godley - One of the best experts on this subject based on the ideXlab platform.
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Satellite Tracking of manta rays highlights challenges to their conservation
PLOS ONE, 2012Co-Authors: Brendan J Godley, Lucy A Hawkes, Matthew J Witt, Sara M Maxwell, Rachel T Graham, Dan W Castellanos, Francisco RemolinaAbstract:We describe the real-time movements of the last of the marine mega-vertebrate taxa to be Satellite tracked – the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as ‘Vulnerable’ to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of Tracking but only 12% of Tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.
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using Satellite Tracking to optimize protection of long lived marine species olive ridley sea turtle conservation in central africa
PLOS ONE, 2011Co-Authors: Sara M Maxwell, Brendan J Godley, Greg A Breed, Barry Nickel, Junior Makangabahouna, Edgard Pemomakaya, Richard J Parnell, Angela Formia, Solange Ngouessono, Daniel P CostaAbstract:Tractable conservation measures for long-lived species require the intersection between protection of biologically relevant life history stages and a socioeconomically feasible setting. To protect breeding adults, we require knowledge of animal movements, how movement relates to political boundaries, and our confidence in spatial analyses of movement. We used Satellite Tracking and a switching state-space model to determine the internesting movements of olive ridley sea turtles (Lepidochelys olivacea) (n = 18) in Central Africa during two breeding seasons (2007-08, 2008-09). These movements were analyzed in relation to current park boundaries and a proposed transboundary park between Gabon and the Republic of Congo, both created to reduce unintentional bycatch of sea turtles in marine fisheries. We additionally determined confidence intervals surrounding home range calculations. Turtles remained largely within a 30 km radius from the original nesting site before departing for distant foraging grounds. Only 44.6 percent of high-density areas were found within the current park but the proposed transboundary park would incorporate 97.6 percent of high-density areas. Though tagged individuals originated in Gabon, turtles were found in Congolese waters during greater than half of the internesting period (53.7 percent), highlighting the need for international cooperation and offering scientific support for a proposed transboundary park. This is the first comprehensive study on the internesting movements of solitary nesting olive ridley sea turtles, and it suggests the opportunity for tractable conservation measures for female nesting olive ridleys at this and other solitary nesting sites around the world. We draw from our results a framework for cost-effective protection of long-lived species using Satellite telemetry as a primary tool.
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migratory dichotomy and associated phenotypic variation in marine turtles revealed by Satellite Tracking and stable isotope analysis
Marine Ecology Progress Series, 2011Co-Authors: Judith A Zbinden, Stuart Bearhop, Philip Bradshaw, Bronwen Gill, Dimitris Margaritoulis, Jason Newton, Brendan J GodleyAbstract:Linking foraging and breeding habitats is key to the understanding of behaviour, ecol- ogy and demography of migratory species. Establishing such connections has long been hampered by the logistical problems of following individuals between foraging and breeding areas, especially in the marine realm. We used variation in nitrogen stable isotope patterns between 2 foraging regions of loggerhead sea turtles Caretta caretta determined from samples of Satellite-tracked indi- viduals to assign untracked turtles to a foraging region. We sought to enhance determination of the relative importance of geographically separated foraging regions and to investigate the relationship between fitness correlates and inferred migratory strategies. Of 18 turtles followed by Satellite Tracking from Zakynthos (Greece), 10 moved north to foraging areas in the Adriatic Sea and the Gulf of Amvrakikos and 8 moved south to foraging areas off the coast of North Africa. Of 51 untracked individuals sampled for stable isotope analysis, we considered the stable isotope signature of 47 to qualify for assignment to foraging areas in the north (n = 22) and south (n = 25). Females foraging north were significantly larger (curved carapace length), and the former group laid larger clutches (even after correction for body length) than turtles foraging south, a fact that can be interpreted as a carry-over effect. Combining Satellite Tracking with stable isotope signatures in marine turtles opens new perspectives into how forensic Tracking methodologies may be used to scale up knowl- edge from electronic Tracking of a limited number of individuals to sample sizes that are more mean- ingful from a population perspective.
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Satellite Tracking of sea turtles where have we been and where do we go next
Endangered Species Research, 2008Co-Authors: Brendan J Godley, J M Blumenthal, Annette C Broderick, Michael S Coyne, Matthew H Godfrey, Lucy A Hawkes, Matthew J WittAbstract:The use of Satellite Tracking for the fundamental and applied study of marine turtles began in the 1980s but has undergone rapid growth in recent years. To provide a background against which to judge the past success and future directions of these research efforts we carried out a com- prehensive review of over 130 scientific papers on the use of this technique in this taxon. We show how Satellite Tracking has changed over time as well as outlining biases in spatial, species and life- stage coverage. Descriptions of migration routes and other habitats have offered novel insights into the basic life history patterns of some species, highlighted focal areas for conservation and reinforced the multi-national nature of the stakeholders of many populations. In foraging areas, knowledge is growing as to how animals move within dynamic seascapes, thus facilitating our understanding of 3-dimensional habitat use and seasonal patterns of behaviour. More experimental approaches have elucidated navigational capabilities and post-release survival following fisheries interaction and long-term captivity. In addition, through the Internet and other media, Satellite Tracking appears to have been effective in engaging public attention in many countries. Finally, we discuss why the use of the technique has increased so markedly over time and point out key areas of concern that we feel should be addressed by the community of researchers and donors who focus on sea turtles.
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Satellite Tracking and analysis tool stat an integrated system for archiving analyzing and mapping animal Tracking data
Marine Ecology Progress Series, 2005Co-Authors: Michael S Coyne, Brendan J GodleyAbstract:Despite the obvious power and advan- tages of the Argos system to track animals by Satellite, the data generated are difficult for many biologists to exploit. A broad range of skills is required to efficiently download, collate, filter and interpret Argos data. Inte- gration of animal movements with other physical (e.g. remote sensing imagery) and anthropogenic (e.g. fish- ery distributions) datasets presents additional technical and computing challenges. The Satellite Tracking and Analysis Tool (STAT) is a freely available system de- signed for biologists who work on animal Tracking; it includes a set of standardized tools and techniques for data management, analysis, and integration with envi- ronmental data. STAT logs in to the Argos computer network each day and downloads all available loca- tions and associated data for each user. These data are parsed and stored in a relational database and auto- matically backed up to an offsite location. A number of data filtering options are available, including setting maximum speed, time or distance between consecutive points, Argos location class, and turning angle. A vari- ety of environmental data layers, including bathymetry, sea surface temperature, sea surface height, ocean cur- rents and chlorophyll, can be sampled for all locations in the STAT database and can be downloaded and incorporated into Tracking maps and animations. STAT also facilitates collaboration and the sharing of animal Tracking information with the wider public and funding organizations. We hope that STAT will act as a catalytic foundation, fostering collaboration among users of Satellite telemetry, and ensuring maximum value from these studies.
Jakob Fahr - One of the best experts on this subject based on the ideXlab platform.
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multi temporal distribution modelling with Satellite Tracking data predicting responses of a long distance migrant to changing environmental conditions
Journal of Applied Ecology, 2012Co-Authors: Marion Gschweng, Jakob Fahr, Peter Berthold, Wolfgang Fiedler, Elisabeth K V KalkoAbstract:Summary 1. Despite the wealth of data available from Satellite Tracking (ST) studies, such data have rarely been used to model species distributions. Using a novel method, we show how to exploit Satellite data to analyse whether and how a migratory species responds to fluctuating environmental conditions in its wintering area. This is particularly crucial for establishing comprehensive conservation measures for rare species in areas that are threatened by increasing land use and climate change. 2. We use ST data of Eleonora’s falcon Falco eleonorae, a long-distance migratory raptor that winters in Madagascar, and assess the performance of static species distribution models (SDM) as well as multi-temporal models. ST data were derived from seven falcons tracked during three consecutive wintering periods and for a total of 2410 bearings, of which 512 locations were used in SDMs. We employed environmental predictors (climate, topography and land cover) with a spatial resolution of 30 arc seconds (c. 1 km2) to match rigorously filtered ST data with an accuracy of ≤1 km. 3. We first created a model with low temporal but high spatial resolution (half-year). To predict suitable habitat for each month of the wintering season, we took advantage of the high temporal resolution inherent in ST data and employed temporally corresponding remote sensing data [Normalized Difference Vegetation Index (NDVI) 10-day composites] together with other variables to create monthly models. 4. We show that ST data are suited to build robust and transferable SDMs despite a low number of tracked individuals. Multi-temporal SMDs further revealed seasonal responses of the study species to changing environmental conditions in its wintering area. 5. Synthesis and applications. We present a transferable approach to predict the potential distribution of organisms as well as their dynamic response to changing environmental conditions. Future conservation management plans could include the prediction of a species’ reaction to changing land-use practices or climate change based on the methodology proposed here. This would provide an early warning system for the decline of populations wintering in remote areas that underlie strong climatic fluctuations.
Hiroyoshi Higuchi - One of the best experts on this subject based on the ideXlab platform.
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Satellite Tracking of the spring migration and habitat use of the brent goose branta bernicla in japan
Ornithological Science, 2016Co-Authors: Tetsuo Shimada, Kenichi Tokita, Naoya Hijikata, Kiyoshi Uchida, Masayuki Kurechi, Hitoshi Suginome, Hiroyoshi Higuchi, Yumi Yamada, Kenichi Tokita, Hiroyoshi HiguchiAbstract:Abstract Japan hosts more than 40% population of Brent Goose Branta bernicla wintering in East Asia. We used Satellite-Tracking technology to monitor the seasonal movements and habitat usage of Brent Goose wintering in northern Japan. We marked five geese on the Oya sandy beach, Miyagi Prefecture, northeast Honshu, on 21 January 2014. The geese utilized areas along the seacoast, especially concentrating at a small bay, close to the capture site. Most of the geese offshore were found at fishery rafts. No geese were found more than 2 km offshore or more than 6 km from the capture site along the seacoast. In early April, the geese left the southern Sanriku coast and moved up to eastern Hokkaido, crossing the sea directly or via the coastal areas of Iwate and Aomori Prefectures. The geese predominantly remained in the vicinity of the Veslovskiy Peninsula, Kunashiri (Kunashir) Island, while some were distributed along the northern coast of the Nemuro Peninsula. We identified eastern Hokkaido and Kunashiri Isla...
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Satellite Tracking of the spring migration and habitat use of the brent goose branta bernicla in japan
Ornithological Science, 2016Co-Authors: Tetsuo Shimada, Naoya Hijikata, Kiyoshi Uchida, Masayuki Kurechi, Hitoshi Suginome, Yumi Yamada, Kenichi Tokita, Hiroyoshi HiguchiAbstract:Abstract Japan hosts more than 40% population of Brent Goose Branta bernicla wintering in East Asia. We used Satellite-Tracking technology to monitor the seasonal movements and habitat usage of Brent Goose wintering in northern Japan. We marked five geese on the Oya sandy beach, Miyagi Prefecture, northeast Honshu, on 21 January 2014. The geese utilized areas along the seacoast, especially concentrating at a small bay, close to the capture site. Most of the geese offshore were found at fishery rafts. No geese were found more than 2 km offshore or more than 6 km from the capture site along the seacoast. In early April, the geese left the southern Sanriku coast and moved up to eastern Hokkaido, crossing the sea directly or via the coastal areas of Iwate and Aomori Prefectures. The geese predominantly remained in the vicinity of the Veslovskiy Peninsula, Kunashiri (Kunashir) Island, while some were distributed along the northern coast of the Nemuro Peninsula. We identified eastern Hokkaido and Kunashiri Isla...
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karateristik habitat musim dingin sikep madu asia pernis ptylorhynchus di talaga bodas jawa barat berbasis data Satellite Tracking
Jurnal Lanskap Indonesia, 2013Co-Authors: Presti Ameliawati, Yeni A Mulyani, Hiroyoshi HiguchiAbstract:ABSTRACT Oriental Honey Buzzards (OHBs, Pernis ptilorhynchus) are migratory raptors which have wintering grounds in Indonesia. OHBs’ wintering habitats can be divided into core and edge habitats with unique landscape characteristics, which influence wintering site selection.TalagaBodasandsurroundingareahas beenidentifiedas wintering habitat of OHB based Satellite Tracking data. Theobjective of this study were to: 1) modeling the distribution of wintering habitat of OHB in Talaga Bodas; 2) analyzemicro habitats of vegetationaspect inTalagaBodas; 3) implications of wintering habitatmanagement inWest Java. Main methodology was combining Satellite-Tracking data of OHB with the GIS/remote sensing datausing logistic regression model. 18 Environmental variable used in this study include nearest distance to the elevation (0-300m, 300-500m, 500-700m, 700-1000m, >1000m),slope (0-3%, 3-8%, 8-15%, 15-25%, 25-40%, >40%) and landcover (water body, paddy field,abandon land,settlement,shrub,plantation,forest). Only 7 variables were detected as important variable for characteririzing the distribution of wintering habitat. Wintering habitat distribution model werepredominantly influenced by 1) slope 25%-40%, 2) elevation 0-300 m, 3) elevation 300-500 m, 4) elevation >1000 m, 5) forest, 6) paddy field and 7) water body. The results of the vegetation analysis’s known that the core habitat biodiversity tend to have less variable than the edge habitats.The results ofthis studywillbe usedformanagement ofwinteringhabitat for OHB. Key words:logistic regression, oriental honey-buzzards, Satellite Tracking, talaga bodas, wintering habitat
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Bird migration and the conservation of the global environment
Journal of Ornithology, 2012Co-Authors: Hiroyoshi HiguchiAbstract:I have collaborated with Asian and American scientists on Satellite-Tracking the migration of birds in East Asia for nearly 20 years. We have tracked the migration of about 20 bird species, including cranes, storks, swans and hawks. We have used the results in a variety of applications, from showing migration routes and the relative importance of each staging site to more advanced analyses including using various data overlays to examine habitat use and the connectivity and network structure of migration pathways. We have also studied the effects of climate change on population trends of swans Satellite-tracked from their wintering areas in Japan to their breeding ground in Russia. Satellite-Tracking is a powerful research tool to study the detailed migration routes, seasonal differences in migration pattern, locations of important sites, and the conservation issues that migratory birds encounter. Migratory birds establish a link not only among natural environments in different countries along their migration routes but also among people in different countries. Further interdisciplinary cooperation is needed to develop Tracking technology, and more international collaboration is required to promote migration studies.
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migration of honey buzzards pernis apivorus based on Satellite Tracking
Ornithological Science, 2005Co-Authors: Hiroyoshi Higuchi, Kenichi Tokita, Haujie Shiu, Hiroshi Nakamura, Akitake Uematsu, Kimihiro Kuno, Motoko Saeki, Masanobu Hotta, Emiko Moriya, Emiko MorishitaAbstract:We Satellite-tracked the migration of two adult and one young Honey-buzzards Pernis apivorus between the Japanese breeding ground and Southeast Asia. In autumn migration, the two adults (A1 and A2) migrated across the East China Sea, then through China, the Indochina and Malay Peninsula, and Sumatra. After Sumatra, A1 arrived in Java for the winter, while A2 moved up through Borneo and reached Mindanao, the Philippines. The young honey-buzzard moved along the coast of the South China Sea to reach the Malay Peninsula for the winter. In spring migration, A1 went up the Malay Peninsula, and then took a route different from its autumn route, moving up inland China, down to North and South Korea, and arrived at the previous breeding site in Japan. A2 followed the autumn route and reached a stopover site in Cambodia. After an undetermined radio silence, it was rediscovered back at its breeding area in Japan. The young stayed at the wintering site, making no apparent effort to get back to the breeding area. The sample size is limited, but these results suggest that the migration of Honey-buzzards is remarkably convoluted and varies considerably with bird age and season.
Peter Berthold - One of the best experts on this subject based on the ideXlab platform.
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multi temporal distribution modelling with Satellite Tracking data predicting responses of a long distance migrant to changing environmental conditions
Journal of Applied Ecology, 2012Co-Authors: Marion Gschweng, Jakob Fahr, Peter Berthold, Wolfgang Fiedler, Elisabeth K V KalkoAbstract:Summary 1. Despite the wealth of data available from Satellite Tracking (ST) studies, such data have rarely been used to model species distributions. Using a novel method, we show how to exploit Satellite data to analyse whether and how a migratory species responds to fluctuating environmental conditions in its wintering area. This is particularly crucial for establishing comprehensive conservation measures for rare species in areas that are threatened by increasing land use and climate change. 2. We use ST data of Eleonora’s falcon Falco eleonorae, a long-distance migratory raptor that winters in Madagascar, and assess the performance of static species distribution models (SDM) as well as multi-temporal models. ST data were derived from seven falcons tracked during three consecutive wintering periods and for a total of 2410 bearings, of which 512 locations were used in SDMs. We employed environmental predictors (climate, topography and land cover) with a spatial resolution of 30 arc seconds (c. 1 km2) to match rigorously filtered ST data with an accuracy of ≤1 km. 3. We first created a model with low temporal but high spatial resolution (half-year). To predict suitable habitat for each month of the wintering season, we took advantage of the high temporal resolution inherent in ST data and employed temporally corresponding remote sensing data [Normalized Difference Vegetation Index (NDVI) 10-day composites] together with other variables to create monthly models. 4. We show that ST data are suited to build robust and transferable SDMs despite a low number of tracked individuals. Multi-temporal SMDs further revealed seasonal responses of the study species to changing environmental conditions in its wintering area. 5. Synthesis and applications. We present a transferable approach to predict the potential distribution of organisms as well as their dynamic response to changing environmental conditions. Future conservation management plans could include the prediction of a species’ reaction to changing land-use practices or climate change based on the methodology proposed here. This would provide an early warning system for the decline of populations wintering in remote areas that underlie strong climatic fluctuations.
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long term Satellite Tracking of white stork ciconia ciconia migration constancy versus variability
Journal of Ornithology, 2004Co-Authors: Peter Berthold, Michael Kaatz, Ulrich QuernerAbstract:During Satellite-Tracking investigations of 140 white storks (Ciconia ciconia), one individual, the long-term world record holder among birds, was followed along 12 migratory journeys over a period of 10 years. This long-term study confirms what previous several-year Tracking studies of white storks had indicated: there can be great variability from year to year in the choice of winter quarters as well as in the routes and times of migration, intermediate destinations and stop-over periods, but constancy of winter quarters and migration routes is also possible. The variability may well be caused by external factors, of which food supply is probably predominant.
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Satellite Tracking OF CORY'S SHEARWATER MIGRATION
The Condor, 2000Co-Authors: Dietrich Ristow, Peter Berthold, Dean Hashmi, Ulrich QuernerAbstract:Abstract Transmitters were attached to four adult male Cory's Shearwaters (Calonectris diomedea) caught at their breeding sites off Crete, Greece, in autumn 1998. The birds had left the Mediterranean by the beginning of December. Two were last recorded in the eastern tropical Atlantic in January/February. The other two wintered east of the Mid-Atlantic Ridge, one at about 10°N, the other one in equatorial waters, and could be tracked until return migration in March/April. The seasonal variation in travel speed is in accordance with a conventional pattern of migration with phases of migration and wintering, rather than continuous movement throughout the nonbreeding cycle. The birds left the Mediterranean later and wintered farther north than expected. We suggest that the known longitudinal cline in body size, morphology, and vocalizations of Cory's Shearwater may also be found in migration behavior.
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Satelliten telemetrie eines gansegeiers gyps fulvus in spanien
Journal of Ornithology, 1991Co-Authors: Peter Berthold, Joachim Griesinger, Eugeniusz Nowak, Ulrich QuernerAbstract:During the autumn migratory period a juvenile Griffon Vulture was followed by Satellite Tracking from the breeding grounds in the Pyrenees to the area of Valencia. Satellite Tracking was performed on the basis of a Toyocom transmitter connected to the Argos system. The bird could be traced over a two-month period from end of September to end of November 1990. After an initial south-ward movement the bird stayed in an arid lowland close to the Ebro valley for a longer period and later again moved southward to an area near Valencia. Before the transmitter's lifetime ended due to battery insuffiency the bird had turned north into an area where Griffon Vultures are common. The experimental bird may have joined a large group of conspecifics, wintering there. The bird could be traced over a total distance of about 2000 km and the longest stage per day was about 80 km. As in the case of another European pilot study that we have recently carried out on Bewick's Swans, Satellite Tracking of a Griffon Vulture proved to be a highly promising method to examine in detail migratory movements as well as ecological aspects on route.
Douglas S Chinn - One of the best experts on this subject based on the ideXlab platform.
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a geopotential model from Satellite Tracking altimeter and surface gravity data gem t3
Journal of Geophysical Research, 1994Co-Authors: F J Lerch, R S Nerem, B H Putney, T L Felsentreger, Braulio V Sanchez, S M Klosko, G B Patel, R G Williamson, J A Marshall, Douglas S ChinnAbstract:An improved model of Earth's gravitational field, GEM-T3, has been developed from a combination of Satellite Tracking, Satellite altimeter, and surface gravimetric data. GEM-T3 provides a significant improvement in the modeling of the gravity field at half wavelengths of 400 km and longer. This model, complete to degree and order 50, yields more accurate Satellite orbits and an improved geoid representation than previous Goddard Earth Models. GEM-T3 uses altimeter data from GEOS 3 (1975–1976), Seasat (1978) and Geosat (1986–1987). Tracking information used in the solution includes more than 1300 arcs of data encompassing 31 different Satellites. The recovery of the long-wavelength components of the solution relies mostly on highly precise Satellite laser ranging (SLR) data, but also includes TRANET Doppier, optical, and Satellite-to-Satellite Tracking acquired between the ATS 6 and GEOS 3 Satellites. The main advances over GEM-T2 (beyond the inclusion of altimeter and surface gravity information which is essential for the resolution of the shorter wavelength geoid) are some improved Tracking data analysis approaches and additional SLR data. Although the use of altimeter data has greatly enhanced the modeling of the ocean geoid between 65°N and 60°S latitudes in GEM-T3, the lack of accurate detailed surface gravimetry leaves poor geoid resolution over many continental regions of great tectonic interest (e.g., Himalayas, Andes). Estimates of polar motion, Tracking station coordinates, and long-wavelength ocean tidal terms were also made (accounting for 6330 parameters). GEM-T3 has undergone error calibration using a technique based on subset solutions to produce reliable error estimates. The calibration is based on the condition that the expected mean square deviation of a subset gravity solution from the full set values is predicted by the solutions' error covariances. Data weights are iteratively adjusted until this condition for the error calibration is satisfied. In addition, gravity field tests were performed on strong Satellite data sets withheld from the solution (thereby ensuring their independence). In these tests, the performance of the subset models on the withheld observations is compared to error projections based on their calibrated error covariances. These results demonstrate that orbit accuracy projections are reliable for new Satellites which were not included in GEM-T3.
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geopotential models of the earth from Satellite Tracking altimeter and surface gravity observations gem t3 and gem t3s
Geopotential models of the Earth from satellite tracking, 1992Co-Authors: F J Lerch, R S Nerem, B H Putney, T L Felsentreger, Braulio V Sanchez, S M Klosko, G B Patel, R G Williamson, Douglas S Chinn, J C ChanAbstract:Improved models of the Earth's gravitational field have been developed from conventional Tracking data and from a combination of Satellite Tracking, Satellite altimeter and surface gravimetric data. This combination model represents a significant improvement in the modeling of the gravity field at half-wavelengths of 300 km and longer. Both models are complete to degree and order 50. The Goddard Earth Model-T3 (GEM-T3) provides more accurate computation of Satellite orbital effects as well as giving superior geoidal representation from that achieved in any previous GEM. A description of the models, their development and an assessment of their accuracy is presented. The GEM-T3 model used altimeter data from previous Satellite missions in estimating the orbits, geoid, and dynamic height fields. Other Satellite Tracking data are largely the same as was used to develop GEM-T2, but contain certain important improvements in data treatment and expanded laser Tracking coverage. Over 1300 arcs of Tracking data from 31 different Satellites have been used in the solution. Reliable estimates of the model uncertainties via error calibration and optimal data weighting techniques are discussed.
