IGGOS as a potential partner in IGOS

This short note reviews our thinking on how IGGOS can best achieve a high status within the set of global monitoring programmes. If such a high status can be obtained, then the importance of geodetic networks and services will be recognized more widely, and their activities will consequently be better resourced in the long term. One particular aspect concerns how IGGOS can complement the roles of the various IGOS partners within global monitoring. The different ways in which IGGOS can contribute to IGOS are outlined.     

Integrated Global Geodetic Observing System (IGGOS)—science rationale

The International Association of Geodesy has decided to establish an Integrated Global Geodetic Observing System (IGGOS). The objective of IGGOS is to integrate in a well-defined global terrestrial reference frame the three fundamental pillars of geodesy, which are the determination of all variations of surface geometry of our planet (land, ice and ocean surfaces), of the irregularities in Earth rotation sub-divided in changes of nutation, polar motion and spin rate, and of the spatial and temporal variations of gravity and of the geoid. This integration will have to be done with a relative precision of 1 part-per-billion and be maintained stable in space and time over decades. IGGOS will quantify on a global scale surface changes, mass anomalies, mass transport and mass exchange and exchange in angular momentum in system Earth. It will be a novel and unique contribution to Earth system and Global Change research. It is intended to make IGGOS part of the Integrated Global Observing Strategy (IGOS).     

Integrated Global Geodetic Observing System (IGGOS)—science rationale

The International Association of Geodesy has decided to establish an Integrated Global Geodetic Observing System (IGGOS). The objective of IGGOS is to integrate in a well-defined global terrestrial reference frame the three fundamental pillars of geodesy, which are the determination of all variations of surface geometry of our planet (land, ice and ocean surfaces), of the irregularities in Earth rotation sub-divided in changes of nutation, polar motion and spin rate, and of the spatial and temporal variations of gravity and of the geoid. This integration will have to be done with a relative precision of 1 part-per-billion and be maintained stable in space and time over decades. IGGOS will quantify on a global scale surface changes, mass anomalies, mass transport and mass exchange and exchange in angular momentum in system Earth. It will be a novel and unique contribution to Earth system and Global Change research. It is intended to make IGGOS part of the Integrated Global Observing Strategy (IGOS).     

地球物理台网仪器监控可视化系统设计与实现

根据地球物理观测台网日常监测工作需求,基于地震观测仪器自动监控软件数据源开发一款可视化软件,用于地球物理台网仪器状态监控。该软件可对仪器设备状态、网络状态、运行状态等进行实时监控,对采集数据中的无效数据、异常变幅、干扰、地震和限幅等监控结果进行报警提示,通过可视化窗口,将及时呈现全球及全国地震信息,并利用智能语音合成技术,实现仪器告警、地震速报信息的语音播报。     

Integration of space geodesy: A US National Geodetic Observatory

In the interest of improving the performance and efficiency of space geodesy a diverse group in the US, in collaboration with IGGOS, has begun to establish a unified National Geodetic Observatory (NGO). To launch this effort an international team will conduct a multi-year program of research into the technical issues of integrating SLR, VLBI, and GPS geodesy to produce a unified set of global geodetic products. The goal is to improve measurement accuracy by up to an order of magnitude while lowering the cost to current sponsors. A secondary goal is to expand and diversify international sponsorship of space geodesy. Principal benefits will be to open new vistas of research in geodynamics and surface change while freeing scarce NASA funds for scientific studies. NGO will proceed in partnership with, and under the auspices of, the International Association of Geodesy (IAG) as an element of the Integrated Global Geodetic Observation System project. The collaboration will be conducted within, and will make full use of, the IAG's existing international services: the IGS, IVS, ILRS, and IERS. Seed funding for organizational activities and technical analysis will come from NASA's Solid Earth and Natural Hazards Program. Additional funds to develop an integrated geodetic data system known as Inter-service Data Integration for Geodetic Operations (INDIGO), will come from a separate NASA program in Earth science information technology. INDIGO will offer ready access to the full variety of NASA's space geodetic data and will extend the GPS Seamless Archive (GSAC) philosophy to all space geodetic data types.     

全球变暖背景下东亚气候变化的最新情景预测

在最新的SRES A2和B2温室气体排放情景下,利用国际上7个气候模式针对未来全球变暖的数值模拟结果,本文着重分析了东亚区域气候21世纪的变化趋势. 研究揭示：中国大陆年均表面气温升高过程与全球同步,但增幅在东北、西部和华中地区较大,且表现出明显的年际变化;全球年均表面气温增幅纬向上大体呈带状分布,两极地区最为明显,并在北极地区达到最大;此外,21世纪后半段北半球高纬度地区的年平均强升温幅度主要来自于冬季增温. 在21世纪前50年,温室气体含量的增加除在一定程度上会增加青藏高原大部分夏季降水量外,不会对中国大陆其余地区的年、季节平均降水量产生较大影响;但持续的温室气体含量增加将最终导致大陆降水量几乎是全域性的增加.     

The GGOS as the backbone for global observing and local monitoring: A user driven perspective

A key geodetic contribution to both the three Global Observing Systems and initiatives like the European Global Monitoring for Environment and Security is an accurate, long-term stable, and easily accessible reference frame as the backbone. Many emerging scientific as well as non-scientific high-accuracy applications require access to an unique, technique-independent reference frame decontaminated for short-term fluctuations due to global Earth system processes. Such a reference frame can only be maintained and made available through an observing system such as the Global Geodetic Observing System (GGOS), which is currently implemented and expected to provide sufficient information on changes in the Earth figure, its rotation and its gravity field. Based on a number of examples from monitoring of infrastructure, point positioning, maintenance of national references frames to global changes studies, likely future accuracy requirements for a global terrestrial reference frame are set up as function of time scales. Expected accuracy requirements for a large range of high-accuracy applications are less than 5 mm for diurnal and sub-diurnal time scales, 2–3 mm on monthly to seasonal time scales, better than 1 mm/year on decadal to 50 years time scales. Based on these requirements, specifications for a geodetic observing system meeting the accuracy requirements can be derived.     

Development of an Information and Database System for the IERS: Status and outlook

The focus of this paper is to present the concepts for a new dynamic, i.e. database-driven information system for the International Earth Rotation and Reference Systems Service (IERS). Its goal is to coordinate the data and information flow between the participating institutions. Therefore, all relevant data and products of the IERS should be archived to guarantee their long-term availability. At the same time the consistency and timeliness of the contents of the information system can be guaranteed by managing the information in a database. Additionally, the metadata of all products (including the IERS publications) should be modelled in a database to allow the users to search for specific data or topics with respect to space, time and content. In order to be able to link related data the heterogeneous formats of the products have to be transformed into a common format. The eXtensible Markup Language (XML) is going to be used, to perform this ambitious task. The usage of XML not only allows to link related data but also to easily exchange data and to present them in different ways like Web pages, pdf, etc. The system will be completed by several tools to manage and coordinate the tasks of the Central Bureau (CB) and by an information system with respect to IERS-related topics. The standardised database tools will also allow an easy exchange of information with and links to other databases within the IGGOS project to realize a powerful instrument to serve the Earth observing system.     

The inhibition of marine nitrification by ocean disposal of carbon dioxide

In an attempt to reduce the threat of global warming, it has been proposed that the rise of atmospheric carbon dioxide concentrations be reduced by the ocean disposal of CO2 from the flue gases of fossil fuel-fired power plants. The release of large amounts of CO2 into mid or deep ocean waters will result in large plumes of acidified seawater with pH values ranging from 6 to 8. In an effort to determine whether these CO2-induced pH changes have any effect on marine nitrification processes, surficial (euphotic zone) and deep (aphotic zone) seawater samples were sparged with CO2 for varying time durations to achieve a specified pH reduction, and the rate of microbial ammonia oxidation was measured spectrophotometrically as a function of pH using an inhibitor technique. For both seawater samples taken from either the euphotic or aphotic zone, the nitrification rates dropped drastically with decreasing pH. Relative to nitrification rates in the original seawater at pH 8, nitrification rates were reduced by ca. 50% at pH 7 and more than 90% at pH 6.5. Nitrification was essentially completely inhibited at pH 6. These findings suggest that the disposal of CO2 into mid or deep oceans will most likely result in a drastic reduction of ammonia oxidation rates within the pH plume and the concomitant accumulation of ammonia instead of nitrate. It is unlikely that ammonia will reach the high concentration levels at which marine aquatic organisms are known to be negatively affected. However, if the ammonia-rich seawater from inside the pH plume is upwelled into the euphotic zone, it is likely that changes in phytoplankton abundance and community structure will occur. Finally, the large-scale inhibition of nitrification and the subsequent reduction of nitrite and nitrate concentrations could also result in a decrease of denitrification rates which, in turn, could lead to the buildup of nitrogen and unpredictable eutrophication phenomena. Clearly, more research on the environmental effects of ocean disposal of CO2 is needed to determine whether the potential costs related to marine ecosystem disturbance and disruption can be justified in terms of the perceived benefits that may be achieved by temporarily delaying global warming.     

The most temperature-adapted corals have an Achilles' Heel

The corals of the Persian/Arabian Gulf are better adapted to temperature fluctuations than elsewhere in the Indo-Pacific. The Gulf is an extreme marine environment displaying the highest known summer water temperatures for any reef area. The small and shallow sea can be considered a good analogue to future conditions for the rest of the world’s oceans under global warming. The fact that corals can persist in such a demanding environment indicates that they have been able to acclimatize and selectively adapt to elevated temperature. The implication being that colonies elsewhere may be able to follow suit. This in turn provides hope that corals may, given sufficient time, similarly adapt to survive even in an impoverished form, under conditions of acidification-driven lowering of CaCO₃ saturation state, a further consequence of raised atmospheric CO₂. This paper demonstrates, however, that the uniquely adapted corals of the Gulf may, within the next three centuries, be threatened by a chronic habitat shortage brought about by the dissolution of the lithified seabed on which they rely for colonisation. This will occur due to modifications in the chemical composition of the Gulf waters due to climate change.     

Uncertainty analysis along the ecological quality status of water bodies: the response of the Posidonia oceanica multivariate index (POMI) in three Mediterranean regions

Uncertainty analyses allow the identification and quantification of the factors that contribute to the potential misclassification of the ecological status of water bodies, helping to improve the sampling design used in monitoring. Here we used a Posidonia oceanica multivariate index (POMI) bio-monitoring dataset covering a total of 81 sites distributed throughout 28 water bodies from the coast of Catalonia, Balearic Islands and Croatia to determine the levels of uncertainty associated with each region and how they change according to the quality status of water bodies. Overall, variability among sites (meadows) within water bodies was the factor that generated the greatest risk of misclassification among the three regions, within which the Balearic Islands had the lowest uncertainty, followed by Croatia and Catalonia. When water bodies classified in good/high quality were separated from those in moderate/poor status classes, we found that the latter displayed higher levels of uncertainty than the former.     

Challenges to global surveillance of disease patterns

Surveillance systems for foodborne disease vary in capacity by country, especially for marine-related illnesses. Generally, the more developed the country is, the more funding that is put into its surveillance programs, but no country has an outstanding system that could serve as a model for all others. An additional problem is lack of consistency. Approaches to surveillance and available resources change over time, so that apparent trends may reflect more of an administrative function. Most countries have some passive system that allows data on foodborne illnesses to be sent to centralized authorities where summaries are generated. However, these depend on the uneven quality of the source data that vary according to the resources allocated at the local level. Active surveillance systems collect data targeted to answer specific epidemiological questions more efficiently, but at such a high cost that most countries do not have the resources, except on a occasional basis. There is also the issue of what to do with the collected data. There has to be a conscious effort to translate the problems identified from the surveillance programs to consider strategies for prevention and control of foodborne disease. Otherwise, there is little value in having these kinds of monitoring programs. Another problem is lack of coordination in surveillance systems between most countries, so that information can be rapidly and efficiently shared. That being said, surveillance over the years had generated much interesting information on how disease agents are transmitted through the food supply, and where contamination and growth by pathogens in the food production and preparation chain typically occur. In addition, attempts are being made to create regional networks in different parts of the world usually initiated by organizations like WHO and PAHO. The kinds of information collected and programs being introduced are discussed in examples taken from both the developed and less developed world, followed by a series of recommendations for improving surveillance on a global basis. A recent burden in the surveillance system is the potential for a deliberate attack on the food supply with agents not usually involved with foodborne illness. At least in the US, a major concern is for the rapid detection and containment of a massive contamination of the food supply.     

Predicting the ecological status of rivers and streams under different climatic and socioeconomic scenarios using Bayesian Belief Networks

Freshwater systems have increasingly been subjected to a multitude of human pressures and the re-establishment of their ecological integrity is currently a major worldwide challenge. Expected future climate and socioeconomic changes will most probably further exacerbate such challenges. Modelling techniques may provide useful tools to help facing these demands, but their use is still limited within ecological quality assessment of water resources due to its technical complexity.We developed a Bayesian Belief Network (BBN) framework for modelling the ecological quality of rivers and streams in two European river basins located in two distinct European climatic regions: the Odense Fjord basin (Denmark) and the Sorraia basin (Portugal). This method enabled us to integrate different data sources into a single framework to model the effect of multiple stressors on several biological indicators of river water quality and, subsequently, on their ecological status. The BBN provided a simple interactive user interface with which we simulated combined climate and socioeconomic changes scenarios to assess their impacts on river ecological status.According to the resulting BBNs the scenarios demonstrated small impacts of climate and socioeconomic changes on the biological quality elements analysed. This yield a final ecological status similar to the baseline in the Odense case, and slightly worse in Sorraia. Since the present situation already depicts a high percentage of rivers and streams with moderate or worse ecological status in both basins, this means that many of them would not fulfil the Water Framework Directive target in the future. Results also showed that macrophytes and fish indices were mainly responsible for a non-desirable overall ecological status in Odense and Sorraia, respectively. The approach followed in this study is novel, since BBN modelling is used for the first time for assessing the ecological status of rivers and streams under future scenarios, using an ensemble of biological quality elements. An important advantage of this tool is that it may easily be updated with new knowledge on the nature of relationships already established in the BBN or even by introducing new causal links. By encompassing two case studies of very different characteristics, these BBN may be more easily adapted as decision-making tools for water management of other river basins.     

The Integrated Global Geodetic Observing System (IGGOS) viewed from the perspective of history

Towards the end of the 19th century, geodetic observation techniques allowed it to create geodetic networks of continental size. The insight that big networks can only be set up through international collaboration led to the establishment of an international collaboration called “Central European Arc Measurement”, the predecessor of the International Association of Geodesy (IAG), in 1864. The scope of IAG activities was extended already in the 19th century to include gravity.At the same time, astrometric observations could be made with an accuracy of a few tenths of an arcsecond. The accuracy stayed roughly on this level, till the space age opened the door for milliarcsecond (mas) astrometry. Astrometric observations allowed it at the end of the 19th century to prove the existence of polar motion. The insight that polar motion is almost unpredictable led to the establishment of the International Latitude Service (ILS) in 1899.The IAG and the ILS were the tools (a) to establish and maintain the terrestrial and the celestial reference systems, including the transformation parameters between the two systems, and (b) to determine the Earth's gravity field.Satellite-geodetic techniques and astrometric radio-interferometric techniques revolutionized geodesy in the second half of the 20th century. Satellite Laser Ranging (SLR) and methods based on the interferometric exploitation of microwave signals (stemming from Quasars and/or from satellites) allow it to realize the celestial reference frame with (sub-)mas accuracy, the global terrestrial reference frame with (sub-)cm accuracy, and to monitor the transformation between the systems with a high time resolution and (sub-)mas accuracy. This development led to the replacement of the ILS through the IERS, the International Earth Rotation Service in 1989.In the pre-space era, the Earth's gravity field could “only” be established by terrestrial methods. The determination of the Earth's gravitational field was revolutionized twice in the space era, first by observing geodetic satellites with optical, Laser, and Doppler techniques, secondly by implementing a continuous tracking with spaceborne GPS receivers in connection with satellite gradiometry. The sequence of the satellite gravity missions CHAMP, GRACE, and GOCE allow it to name the first decade of the 21st century the “decade of gravity field determination”.The techniques to establish and monitor the geometric and gravimetric reference frames are about to reach a mature state and will be the prevailing geodetic tools of the following decades. It is our duty to work in the spirit of our forefathers by creating similarly stable organizations within IAG with the declared goal to produce the geometric and gravimetric reference frames (including their time evolution) with the best available techniques and to make accurate and consistent products available to wider Earth sciences community as a basis for meaningful research in global change. IGGOS, the Integrated Global Geodetic Observing System, is IAG's attempt to achieve these goals. It is based on the well-functioning and well-established network of IAG services.     

云南地方地震前兆监测资源的整合

通过分析云南省地震前兆监测目前的现状,提出整合全省前兆监测资源的方案。该方案的实施可以使全省近500套仪器的前兆监测资源能够得到有效监控、规范存储和充分运用。这将有利于云南省的地震监测预报,也有利于未来时期的监测规划。     

南中国海区域海啸预警中心地震监测系统

简要介绍了南中国海区域海啸预警与减灾系统的建设和发展历程,同时重点阐述了地震监测系统构成及其基本功能。作为重要组成部分,地震监测系统通过地震数据的实时汇集、存储、自动处理和分析,并结合人机交互方式实现了地震定位、震源机制解和有限断层模型反演。实际应用表明,地震监测系统对全球6.0级以上地震定位时间不超过8 min,在震后10—15 min内完成W震相方法快速反演海底强震震源机制解,在震后短时间内完成有限断层模型反演,为海啸预警提供快速、准确、可靠的地震基本参数和震源特征参数。      

Transforming management of tropical coastal seas to cope with challenges of the 21st century

Over 1.3 billion people live on tropical coasts, primarily in developing countries. Many depend on adjacent coastal seas for food, and livelihoods. We show how trends in demography and in several local and global anthropogenic stressors are progressively degrading capacity of coastal waters to sustain these people. Far more effective approaches to environmental management are needed if the loss in provision of ecosystem goods and services is to be stemmed. We propose expanded use of marine spatial planning as a framework for more effective, pragmatic management based on ocean zones to accommodate conflicting uses. This would force the holistic, regional-scale reconciliation of food security, livelihoods, and conservation that is needed. Transforming how countries manage coastal resources will require major change in policy and politics, implemented with sufficient flexibility to accommodate societal variations. Achieving this change is a major challenge – one that affects the lives of one fifth of humanity.     

The International Laser Ranging Service and its support for IGGOS

The International Laser Ranging Service (ILRS) was established in September 1998 as a service within the IAG to support programs in geodetic, geophysical, and lunar research activities and to provide data products to the International Earth Rotation Service (IERS) in support of its prime objectives. Now in operation for 5 years, the ILRS develops: (1) the standards and specifications necessary for product consistency and (2) the priorities and tracking strategies required to maximize network efficiency. The service collects, merges, analyzes, archives and distributes satellite and lunar laser ranging data to satisfy a variety of scientific, engineering, and operational needs and encourages the application of new technologies to enhance the quality, quantity, and cost effectiveness of its data products. The ILRS works with: (1) the global network to improve station performance; (2) new satellite missions in the design and building of retroreflector targets to maximize data quality and quantity and (3) science programs to optimize scientific data yield. The ILRS Central Bureau maintains a comprehensive web site as the primary vehicle for the distribution of information within the ILRS community. The site, which can be accessed at: http://ilrs.gsfc.nasa.gov is also available at mirrored sites at the Communications Research Laboratory (CRL) in Tokyo and the European Data Center (EDC) in Munich.During the last 2 years, the ILRS has addressed very important challenges: (1) data from the field stations are now submitted hourly and made available immediately through the data centers for access by the user community; (2) tracking on low satellites has been significantly improved through the sub-daily issue of predictions, drag functions, and the real-time exchange of time biases; (3) analysis products are now submitted in SINEX format for compatibility with the other space geodesy techniques; (4) the Analysis Working Group is heavily engaged in Pilot Projects as it works toward an ILRS “standard” global solution and (5) SLR has significantly increased its participation in the International Terrestrial Reference Frame (ITRF) activity, which is important to the success of IGGOS.     

Sea-level rise: A review of recent past and near-future trends

Global mean sea level is a potentially sensitive indicator of climate change. Global warming will contribute to worldwide sea-level rise (SLR) from thermal expansion of ocean water, melting of mountain glaciers and polar ice sheets. A number of studies, mostly using tide-gauge data from the Permanent Service for Mean Sea Level, Bidston Observatory, England, have obtained rates of global SLR within the last 100 years that range between 0·3 and 3 mm yr^?1, with most values concentrated between 1 and 2 mm yr^?1. However, the reliability of these results has been questioned because of problems with data quality and physical processes that introduce a high level of spatial and temporal variability. Sources of uncertainty in the sea-level data include variations in winds, ocean currents, river runoff, vertical earth movements, and geographically uneven distribution of long-term records. Crustal motions introduce a major source of error. To a large extent, these can be filtered by employing palaeo-sea-level proxies, and geophysical modelling to remove glacio-isostatic changes. Ultimately, satellite geodesy will help resolve the inherent ambiguity between the land and ocean level changes recorded by tide gauges. Future sea level is expected to rise by ～ 1 m, with a ‘best-guess’ value of 48 cm by the year 2100. Such rates represent an acceleration of four to seven times over present rates. Local land subsidence could substantially increase the apparent SLR. For example, Louisiana is currently experiencing SLR trends nearly 10 times the global mean rate. These recently reduced SLR estimates are based on climate models that predict a zero to negative contribution to SLR from Antarctica. Most global climate models (GCMs) indicate an ice accumulation over Antarctica, because in a warmer world, precipitation will exceed ablation/snow-melt. However, the impacts of attritional processes, such as thinning of the ice shelves, have been downplayed according to some experts. Furthermore, not all climate models are in agreement. Opposite conclusions may be drawn from the results of other GCMs. In addition, the West Antarctic Ice Sheet is potentially subject to dynamic and volcanic instabilities that are difficult to predict. Because of the great uncertainty in SLR projections, careful monitoring of future sea-level trends by upgraded tide-gauge networks and satellite geodesy will become essential. Finally, because of the high spatial variability in crustal subsidence rates, wave climates and tidal regimes, it will be the set of local conditions (especially the relative sea-level rise), rather than a single global mean sea-level trend, that will determine each locality's vulnerability to future SLR.