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11.
Ranjeet Devarakonda Giriprakash Palanisamy Bruce E. Wilson James M. Green 《Earth Science Informatics》2010,3(1-2):87-94
Mercury is a federated metadata harvesting, search and retrieval tool based on both open source packages and custom software developed at Oak Ridge National Laboratory (ORNL). It was originally developed for the National Aeronautics and Space Administration (NASA), and the consortium now includes funding from NASA, U.S. Geological Survey (USGS), and U.S. Department of Energy (DOE). Mercury is itself a reusable software application which uses a service-oriented architecture (SOA) approach to capturing and managing metadata in support of twelve Earth science projects. Mercury also supports the reuse of metadata by enabling searches across a range of metadata specification and standards including XML, Z39.50, FGDC, Dublin-Core, Darwin-Core, EML, and ISO-19115. It collects metadata and key data from contributing project servers distributed around the world and builds a centralized index. The Mercury search interfaces allows the users to perform simple, fielded, spatial, temporal and other hierarchical searches across these metadata sources. This centralized repository of metadata with distributed data sources provides extremely fast search results (Table 1) to the user, while allowing data providers to advertise the availability of their data and yet maintain complete control and ownership of that data. 相似文献
12.
Data sharing and retrieval using OAI-PMH 总被引：2，自引：1，他引：1
Ranjeet Devarakonda Giri Palanisamy James M. Green Bruce E. Wilson 《Earth Science Informatics》2011,4(1):1-5
There is a growing consensus for the need to store and archive digital data, particularly for publicly funded research. Long-term
preservation of that data generally requires some form of institutional archive, such as those directed to particular scientific
communities of practice. Given that data is often of use to multiple communities of practice, which may have differing norms
for data and metadata structure and semantics, effective standards for data and metadata exchange are important factors for
users to be able to find and retrieve data. Toolsets that provide a coherent presentation of information across multiple standards
are important for data search and access. One such toolset, Mercury, is a open-source metadata harvesting, data discovery,
and access system, built for researchers to search for, share and obtain spatiotemporal data used across a range of climate
and ecological sciences. Mercury is used across multiple projects to provide a coherent search interface for spatiotemporal
data described in any of several metadata formats. Mercury has recently been extended to enable harvesting and distribution
of metadata using the Open Archive Initiative Protocol for Metadata Handling (OAI-PMH). In this paper we describe Mercury’s
capabilities with multiple metadata formats, in general, and, more specifically, the results of our OAI-PMH implementations
and the lessons learned. 相似文献
13.
High-precision satellite altimeters help in measuring the variations in sea level since the early 1990s. After a number of such successful altimetry missions such as Topex/Poseidon, Jason-1, Jason-2, and Envisat, SARAL/AltiKa, a high resolution altimetry mission based on the Ka frequency band that can also cover high latitudinal zones, was launched in February 2013. Even though the data set available from this recent mission is not yet suitable for climate research owing to its short duration, in this study we perform a preliminary validation of SARAL/AltiKa sea-level data. The first part of the validation is the comparison of SARAL/AltiKa and Jason-2 sea-level data between March 2013 and August 2014 in terms of temporal mean spatial pattern. Comparisons in terms of global mean sea-level time series and latitudinal band-based mean time series are also performed. The second part of the validation is the comparison of the SARAL/AltiKa sea-level based time series with several tide gauge records covering the period of our study. Finally, an analysis of the annual sea-level budget with SARAL/AltiKa data, steric sea level, and ocean mass is performed. Results of these preliminary comparisons show good agreement with other sea-level data. 相似文献
14.
The focus of the study is to explore the recent trend of the world tuna fishery with special reference to the Indian Ocean tuna fisheries and its conservation and sustainable management. In the Indian Ocean, tuna catches have increased rapidly from about 179959 t in 1980 to about 832246 t in 1995. They have continued to increase up to 2005; the catch that year was 1201465 t, forming about 26% of the world catch. Since 2006 onwards there has been a decline in the volume of catches and in 2008 the catch was only 913625 t. The Principal species caught in the Indian Ocean are skipjack and yellowfin. Western Indian Ocean contributed 78.2% and eastern Indian Ocean 21.8% of the total tuna production from the Indian Ocean. The Indian Ocean stock is currently overfished and IOTC has made some recommendations for management regulations aimed at sustaining the tuna stock. Fishing operations can cause ecological impacts of different types: by catches, damage of the habitat, mortalities caused by lost or discarded gear, pollution, generation of marine debris, etc. Periodic reassessment of the tuna potential is also required with adequate inputs from exploratory surveys as well as commercial landings and this may prevent any unsustainable trends in the development of the tuna fishing industry in the Indian Ocean. 相似文献
15.
Marta Marcos Ben Marzeion Sönke Dangendorf Aimée B. A. Slangen Hindumathi Palanisamy Luciana Fenoglio-Marc 《Surveys in Geophysics》2017,38(1):329-348
In this paper we review and update detection and attribution studies in sea level and its major contributors during the past decades. Tide gauge records reveal that the observed twentieth-century global and regional sea level rise is out of the bounds of its natural variability, evidencing thus a human fingerprint in the reported trends. The signal varies regionally, and it partly depends on the magnitude of the background variability. The human fingerprint is also manifested in the contributors of sea level for which observations are available, namely ocean thermal expansion and glaciers’ mass loss, which dominated the global sea level rise over the twentieth century. Attribution studies provide evidence that the trends in both components are clearly dominated by anthropogenic forcing over the second half of the twentieth century. In the earlier decades, there is a lack of observations hampering an improved attribution of causes to the observed sea level rise. At certain locations along the coast, the human influence is exacerbated by local coastal activities that induce land subsidence and increase the risk of sea level-related hazards. 相似文献
16.
Developing countries are vulnerable to tropical cyclones due to climatic variability and the frequency and magnitude of some extreme weather and disaster events is likely to increase. Cities and towns situated along the coastal belt of Visakhapatnam district experienced severe damage because of Hudhub cyclone (12 October 2014). The main objective of this research was to identify and quantify the damage to agriculture and vegetation caused by Hudhud cyclone. In this study, landsat-8 satellite data-sets acquired before and after the cyclone have been used; image processing techniques have been carried out to assess the changes of pre- and post-cyclone condition. Economic loss of agriculture crops has been assessed using crop production loss per hectare and total economic loss for agriculture crops in the study area was calculated. Classification results and land use land cover change analysis show that 13.25% of agriculture-Kharif and 31.1% of vegetation was damaged. Crop Biomass was estimated with aid of crop conversion factor for pre- and post-cyclone conditions. Total ‘Above ground biomass’ of the agriculture crop area was estimated at 31.57 t/ha and total loss of biomass was assessed to be 4.2 t/ha. Carbon stock was found to be varying from 0.3 to 8.3 t.C/ha in specific agriculture crops. From the results, it was concluded that Hudhud has done significant damage to the rural and urban areas of Visakhapatnam. The outcome of this study can be used by decision-makers for the release of post disaster relief fund to affected areas. 相似文献
17.
Observed hydrographs: on their ability to infer a time‐invariant hydrological transfer function for flow prediction in ungauged basins 
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下载免费PDF全文 Streamflow measurements provide information about the flow generation characteristics of land surfaces as well as the flow transferring nature of the channel network. In this study, such flow transferring properties of the channel network that were obtained from downstream flow observations were used for predicting flow in ungauged basins. A temporally averaged transfer function (ATF) of the channel segments of Kentucky River Basin (KRB) in Kentucky, USA, was extracted from observed hydrographs in a time‐invariant system as a function of drainage area. The ATF was regionalized through multiple regression analysis for 194 combinations of drainage areas that differ in topography, terrain, and geology. The application of ATF for flow prediction in ungauged basins was performed for Goose Creek, a subbasin of KRB by integrating ATF with the TOPMODEL. In addition, the ATF was shown to be capable of providing calibration and validation data for ungauged basins in a backward technique from a measured stream gauge downstream, with minimal data requirement of drainage area. The applicability of ATF was illustrated across a range of streamflow conditions from watersheds that varied greatly in their terrain and geology. Nash–Sutcliffe efficiency of the proposed method, as a function of drainage areas of the corresponding basins, to predict daily streamflow from ungauged basins ranged from 0.83 to 0.92. The results of the study concluded that the ATF obtained from measured streamflow thus proved to be a quick and simple tool for assessment of streamflow in both operational and modeling hydrology. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
18.
Yu -Hwan Ahn Palanisamy Shanmugam Kyung- Il Chang Jeong -Eon Moon Joo -Hyung Ryu 《Ocean Science Journal》2005,40(2):67-71
Complex physical, chemical and biological interactions off the Korean coast created several striking patterns in the phytoplankton
blooms, which became conspicuous during the measurements of ocean color from space. This study concentrated on analyzing the
spatial and temporal aspects of phytoplankton chlorophyll variability in these areas using an integrated dataset from a Sea-viewing
Wide Field-of-view Sensor (SeaWiFS), Advanced Very High Resolution (AVHRR) sensor, and Conductivity Temperature Depth (CTD)
sensor. The results showed that chlorophyll concentrations were elevated in coastal and open ocean regions, with strong summer
and fall blooms, which appeared to spread out in most of the enclosed bays and neighboring waters due to certain oceanographic
processes. The chlorophyll concentration was observed to range between 3 and 54 mg m-3 inside Jin-hae Bay and adjacent coastal bays and 0.5 and 8 mg m-3 in the southeast sea offshore waters, this gradual decrease towards oceanic waters suggested physical transports of phytoplankton
blooms from the shallow shelves to slope waters through the influence of the Tsushima Warm Current (TWC) along the Tsushima
Strait. Horizontal distribution of potential temperature (θ) and salinity (S) of water off the southeastern coast exhibited
cold and low saline surface water (θ<19°C; S<32.4) and warm and high saline subsurface water (θ>12°C; S>34.4) at 75dBar, corroborating
TWC intrusion along the Tsushima Strait. An eastward branch of this current was called the East Korean Warm Current (EKWC),
tracked with the help of CTD data and satellite-derived sea surface temperature, which often influenced the dynamics of mesoscale
anticyclonic eddy fields off the Korean east coast during the summer season. The process of such mesoscale anticyclonic eddy
features might have produced interior upwelling that could have shoaled and steepened the nutricline, enhancing phytoplankton
population by advection or diffusion of nutrients in the vicinity of Ulleungdo in the East Sea. 相似文献