U23C-1447
Back to the Future: Long-Term Seismic Archives Revisited
Archives of digital seismic data recorded by seismometer networks around the world have grown tremendously over the last several decades helped by the deployment of seismic stations and their continued operation within the framework of monitoring seismic activity. These archives typically consist of waveforms of seismic events and associated parametric data such as phase arrival time picks and the location of hypocenters. Catalogs of earthquake locations are fundamental data in seismology, and even in the Earth sciences in general. Yet, these locations have notoriously low spatial resolution because of errors in both the picks and the models commonly used to locate events one at a time. This limits their potential to address fundamental questions concerning the physics of earthquakes, the structure and composition of the Earth's interior, and the seismic hazards associated with active faults. We report on the comprehensive use of modern waveform cross-correlation based methodologies for high- resolution earthquake location - as applied to regional and global long-term seismic databases. By simultaneous re-analysis of two decades of the digital seismic archive of Northern California, reducing pick errors via cross-correlation and model errors via double-differencing, we achieve up to three orders of magnitude resolution improvement over existing hypocenter locations. The relocated events image networks of discrete faults at seismogenic depths across various tectonic settings that until now have been hidden in location uncertainties. Similar location improvements are obtained for earthquakes recorded at global networks by re- processing 40 years of parametric data from the ISC and corresponding waveforms archived at IRIS. Since our methods are scaleable and run on inexpensive Beowulf clusters, periodic re-analysis of entire archives may thus become a routine procedure to continuously improve resolution in existing catalogs. We demonstrate the role of seismic archives in obtaining the precise location of new events in real-time. Such information has considerable social and economic impact in the evaluation and mitigation of seismic hazards, for example, and highlights the need for consistent long-term seismic monitoring and archiving of records.
U23C-1448
50 years of Global Seismic Observations
Seismological recordings have been made on Earth for hundreds of years in some form or another, however, global monitoring of earthquakes only began in the 1890's when John Milne created 40 seismic observatories to measure the waves from these events. Shortly after the International Geophysical Year (IGY), a concerted effort was made to establish and maintain a more modern standardized seismic network on the global scale. In the early 1960's, the World-Wide Standardized Seismograph Network (WWSSN) was established through funding from the Advanced Research Projects Agency (ARPA) and was installed and maintained by the USGS's Albuquerque Seismological Laboratory (then a part of the US Coast and Geodetic Survey). This network of identical seismic instruments consisted of 120 stations in 60 countries. Although the network was motivated by nuclear test monitoring, the WWSSN facilitated numerous advances in observational seismology. From the IGY to the present, the network has been upgraded (High-Gain Long-Period Seismograph Network, Seismic Research Observatories, Digital WWSSN, Global Telemetered Seismograph Network, etc.) and expanded (International Deployment of Accelerometers, US National Seismic Network, China Digital Seismograph Network, Joint Seismic Project, etc.), bringing the modern day Global Seismographic Network (GSN) to a current state of approximately 150 stations. The GSN consists of state-of-the-art very broadband seismic transducers, continuous power and communications, and ancillary sensors including geodetic, geomagnetic, microbarographic, meteorological and other related instrumentation. Beyond the GSN, the system of global network observatories includes contributions from other international partners (e.g., GEOSCOPE, GEOFON, MEDNET, F-Net, CTBTO), forming an even larger backbone of permanent seismological observatories as a part of the International Federation of Digital Seismograph Networks. 50 years of seismic network operations have provided valuable data for earth science research. Developments in communications and other technological advances have expanded the role of the GSN in rapid earthquake analysis, tsunami warning, and nuclear test monitoring. With such long-term observations, scientists are now getting a glimpse of Earth structure changes on human time scales, such as the rotation of the inner core, as well as views into climate processes. Continued observations for the next 50 years will enhance our image of the Earth and its processes. http://www.iris.edu/about/GSN
U23C-1449
GEOPHYSICAL SITE CHARACTERIZATION USING SPACE-BASED IMAGERY AND INTEGRATED IMAGING ANALYSIS METHODS: AN OVERVIEW
The identification of active faults and the estimation of local geological site conditions are critical components of seismic hazard assessment. Precise information about regional and local geomorphic and geologic conditions are required to characterize both of these components. In many regions of the world, map information about the character of local terrain is imprecise, sparse, or is not readily available. Because of this, seismic hazard maps for many regions in the world are based on an imprecise assessment of active faults and without consideration of site conditions. We report on our development of methods using high-resolution, multi-spectral, remote sensing data to identify surficial fault features and to provide preliminary site characterizations for estimating ground motions in future earthquakes. Our data sets consist of: 1) optical imagery that include regions in the visible near-infrared (VNIR) through the thermal infrared (TIR) domains, and 2) relative digital elevation models (DEM), based on stereoscopic-correlation methods, derived from NASA's ASTER (Advanced Space-borne Thermal Emission and Reflection Radiometer) sensors. To identify active fault features, we apply edge-detection imaging analysis technology based on contrasts in the luminous intensity in our data. To determine terrain features that control ground motion, we apply automatic object-oriented and pixel-based feature extraction methods on the relative DEM and optical ASTER data, respectively. Using site classification schemes from the Wills et al (2000) and Wills and Clahan (2006) maps of California, we assign Vs30 values for selected regions in California, Afghanistan and Pakistan. Our results demonstrate that detailed site characterization maps, the key basis for microzonation, can be determined from remote-sensing imagery in parts of the world where conventional geological maps are limited or unavailable.
U23C-1450
Technical and Organizational Lessons Learned From More Than One Decade of the International GNSS Service Global Tracking Network
The International GNSS Service (IGS) is a voluntary collaboration of more than 200 worldwide agencies that pool resources to generate precise GPS and GLONASS products. The foundation of the IGS is a global network of 385 permanent, continuous, geodetic-quality stations independently operated by about 100 agencies. The IGS Central Bureau develops minimum functional requirements and operational standards that enable the individual stations' data to be used coherently in global analyses, but the IGS remains vendor neutral, leaving procurement decisions and implementation details to the individual agencies. The IGS network is hence quite heterogeneous in instrumentation, station management strategies, and culture; these diversities bring both strengths and challenges in coordination. This presentation will detail the IGS's approaches, successes, and opportunities for improvement in coordinating and monitoring the collaborative network. http://igscb.jpl.nasa.gov
U23C-1451
Assessment of Precision and Accuracy of GPS Radio Occultation Data From the COSMIC/ FORMOSAT-3 Mission
The Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) / Formosa Satellite 3 (FORMOSAT-3) is a new six-satellite radio occultation (RO) mission that was successfully launched in mid-April, 2006. The UCAR COSMIC Data Analysis and Archival Center (CDAAC) receives the COSMIC data in near real- time, and performs the functions of precise orbit determination, excess phase calibration, neutral atmospheric inversion, quality control checking, and dissemination of data products to operational weather centers within 3 hours of observation. The CDAAC also generates more precise post-processed data products for climate applications. This presentation initially gives an overview of the data processing details performed at the CDAAC. Then, the presentation provides a summary assessment of COSMIC near real-time and post-processed data quality. Preliminary assessments have shown that the GPS RO data from COSMIC are of better quality than those from the previous missions and penetrate much farther down into the troposphere; from 70 to 90 percent of the soundings reach to within 1 km of the surface on a global basis. The precision of COSMIC RO refractivity profiles, estimated by comparing collocated COSMIC soundings, is shown to have an RMS difference of refractivity between 10 and 20 km altitude of less than 0.2%. The accuracy of the COSMIC soundings is also assessed via comparisons to GPS RO soundings from other missions, radiosondes, and numerical weather prediction models from NCEP and ECMWF. http://www.cosmic.ucar.edu
U23C-1452
Early Earth Science Activities in the Sanford Underground Science and Engineering Laboratory at Homestake
On July 10, 2007, the former Homestake Mine, Lead, South Dakota, was selected as the development site for the Deep Underground Science and Engineering Laboratory, to become the Sanford Underground Science and Engineering Laboratory at Homestake. Work on refurbishment and certification of the Ross Shaft began in August 2007 to effect pumping of water that had reached the 5000 level in late July. Completion of this work will allow a physics and geosciences laboratory to be constructed on the 4,850 ft level (1,478 m from the surface). Concurrent with reentry operations, several earth science research activities have been initiated. These early activities are as follows: (1) Seismic monitoring system: Accelerometers will be installed in surface boreholes and underground drifts as they become available as a result of the reentry work. (2) Evaluation of the 300 level (91 m), which has multiple locations for horizontal access, is ongoing. This near- surface level, with varying overburden thicknesses, offers excellent opportunities to investigate the "critical zone" in terms of hydrology, ecology, and geochemistry, yielding measurements of both moisture and carbon fluxes to evaluate fluid exchanges with the atmosphere. (3) Water and soil samples were collected in the Ross Shaft as part of the first reentry work. Molecular survey of microbial diversity showed the presence of mesophilic and thermophilic cellulose-degrading microorganisms. (4) Supercritical carbon dioxide injection experiments are being planned that will take advantage of three pairs of existing, nearly vertical, open 8-inch (0.2 m) boreholes that are easily accessible from the Ross Shaft. The candidate holes are located between the 1550 and the 2900 levels and are between 90 to 180 m in length (5) Monitoring of the response of the water during the dewatering operations will be facilitated by the use of existing boreholes. Ultimately, the dewatering operation provide access to the 8000 level (depth of 2,438 m), the deepest level. These five examples of ongoing research activities should provide a basis for many other earth science and engineering investigations at this multilevel facility, which already has extensive underground workings. These examples address different aspects of three main themes identified as important by deep underground research communities: restless earth for geo-science, ground truth for geo-engineering, and dark life for geo-microbiology.
U23C-1453
A Future Network for Monitoring the Driving Function of Global Warming
A new future network is proposed to monitor the radiative forcing of global warming by greenhouse gases. The greenhouse radiation is the downward infrared heat radiation from greenhouse gases, otherwise known as the surface forcing radiation. The increase in this radiation due to increased carbon dioxide and other greenhouse gases is the driving function of global warming. In an experimental project, the calibrated spectrum of the greenhouse radiation at the surface has been measured for the last 10 years in the Great Lakes area. From these measurements the radiative flux from each greenhouse gas has been extracted. There is a 10 year record of the radiative fluxes from carbon dioxide, methane, nitrous oxide and CFCs. The increases in these fluxes represent the forcing function of global warming. It is an experimental version of radiative forcing similar to but different from the radiative forcing used by IPCC. It is proposed that this radiative forcing should be monitored in a fashion similar to our monitoring of the ozone layer. A world monitoring network like the world total ozone monitoring network of Brewer and Dobson spectrophotometers should be setup. The AERI instrument already exists and there are 12 of them deployed around the world; it is manufactured by ABB BOMEM. The methodology will be to process the AERI infrared spectrometer measurements into the downward surface radiation flux in W/m2 from each of the major greenhouse gases. Well calibrated infrared spectral measurements of the downward infrared long wave radiation have been routinely made by the AERI instruments at the three main DOE ARM sites for over 7 years with a 12 year record at the SGP site. These are being processed into long wave radiation fluxes from each of the major greenhouse gases using a methodology already developed for similar measurements at 44° N in the Great Lakes area. The uses of the data would be to investigate the seasonal and climate regime variations of the surface greenhouse radiation flux, compare the measurements with climate model simulations of the surface forcing radiation fluxes for each greenhouse gas, evaluate the reduction of the surface forcing radiation by various types of clouds by measuring the reduction in surface radiation forcing under cloudy conditions, conduct complementary measurements of surface radiation forcing with radiative trapping measured from space with overpasses of satellites and monitor the increase with time of the forcing radiation from each gas. This network will provide a new experimental dataset which would complement the calculated radiative forcings from climate models which are currently used for policy determination of safe levels of greenhouse gases in the atmosphere. The new network will give us the experimental capability to conduct long-term monitoring of the increases in greenhouse radiation due to increases in the individual greenhouse gases without using an intervening climate model. This also adds a new climate observable which could potentially be used to compare changes in the long wave radiation balance of the atmosphere with other climate variables. Hence, the world should monitor this important variable instead of relying solely on model calculations of radiative forcing since it is the fundamental forcing function of global warming. The analysis of the data from ARM AERI sites would represent a big step towards building a world monitoring network for this very important climate observable. With AERI instruments deployed around the globe, a first step in building a network to monitor radiative forcing similar to the world ozone monitoring network has already taken place. This future network emphasizes the extreme importance of continuing the DOE ARM AERI measurements for the foreseeable future.
U23C-1454
The ICSU World Data Center System: Meeting the Long-Term Data Management Requirements of the Global Earth Observation Programs.
The International Council for Science (ICSU) World Data Center (WDC) system, established 50 years ago in the United States, Europe, Russia, and Japan with 27 original centers, has since expanded to other countries and to new scientific disciplines and now encompasses 51 Centers in 12 countries. Its holdings include a wide range of solar, geophysical, environmental, and human dimensions data. These data cover timescales ranging from seconds to millennia, and spatial scales ranging from atomic to galactic dimensions. The WDCs have been very successful over the last five decades in meeting the needs of ICSU programs. They provide baseline information for research in many ICSU disciplines. However, in the next half-century, the WDC system will need to evolve in order to accommodate the changing needs of managing data from the many Earth observation programs of the global scientific community. Advances in information technology, the implementation of new global scientific programs and the rapid increase in global, high-speed network connectivity will require the WDC system to adapt their current infrastructure, reorient their activities and implement new modes of operation. New requirements of existing ICSU programs like the IGBP, the Global Observing Systems (G*OS), the activities of the new international science years (International Polar Year (IPY), IHY, eGY, IYPE) and the implementation of the far reaching, long-term, Global Earth Observation System of Systems (GEOSS), will make new demands on the WDCs. The near-term response to this challenge will be that the WDCs specifically begin to address the data management needs of the International Polar Year, which is a major international research program that has recognized the need for long-term data stewardship. The other near-term priority for the WDC system is to begin working with GEOSS, which is looking to the WDCs for data management expertise in developing the next generation of international, interoperable Earth observing systems aimed at both scientific and practical applications. The WDCs individually and as a system need to demonstrate their willingness to work with the international scientific community and the Earth Observations community to make the IPY and GEOSS successful not only in terms of current needs, but long-term data accessibility and usability. Generally, under ICSU guidance, the WDC system will respond by modernizing its capabilities; introducing WDCs into new disciplines and/or merging with other relevant ICSU data activities; broadening the System geographically, especially into developing countries; and being more proactive in addressing new requirements from ICSU and the global scientific community. http://www.ngdc.noaa.gov/wdc/wdcmain.html
U23C-1455
Thirty Years of Data Management for Earth Observations at the National Snow and Ice Data Center (NSIDC)
Over the past 30 years the National Snow and Ice Data Center (NSIDC) has managed data in a way that directly or indirectly supports earth observations. NSIDC's Distributed Active Archive Center (DAAC) supports the cryospheric missions of the NASA Earth Observing System's satellites. The new Cooperative Data and Information System (CADIS), joint with NCAR and UCAR, supports the (largely) NSF funded Arctic Observing Network (AON). Indirectly, NSIDC supports the Global Climate Observing System and other Earth monitoring efforts by archiving data that contribute to their missions. Some simple truths about observing systems emerge from our long history of storing and serving their data. They include: New instruments have to be "backward compatible" with old. A few long, continuous, records are at least as valuable as numerous sporadic new short records from a number of PIs or satellite programs, even if the short records are more precise. International collaborations are essential for building networks and for establishing data sharing protocols. Examples of currently active NSIDC affiliations include International Polar Year Data Coordination Service of ICSU (International Council for Science), the International Permafrost Association, the World Glacier Monitoring Service, and the Joint WMO-IOC Commission for Oceanography and Maritime Meteorology (JCOMM) for the Global Sea Ice Data Bank. While some observations are useful on their own (like sea ice or snow extent) many are only informative when combined with other like or contrasting observations in some way. It is difficult to get funding for developing higher level or integrative products like atlases, climatologies, near-real-time data streams, or even data on the same grid or in the same format, but these are some of NSIDC's most used data sets. They include the first global assembly of data and information on frozen ground (CAPS), Environmental Atlases for arctic meteorology, oceanography, and sea ice; and passive microwave gridded time series products from the ESMR, SMMR, SSMI, and AMSR-E sensors. Strategic IT decisions impact the cost and effectiveness of systems for managing and distributing observing system data. The challenge to IT managers is the continuing need to drive costs downward yet continue the same level of service in an ever changing technology and user requirements world. The NSIDC DAAC EOSDIS Core System has evolved over the past 10 years and will no doubt change even more in the near future. The Global Land Ice Measurements from Space (GLIMS) project exemplifies the effective linking of older limited-coverage IGY-era paper maps to a modern geospatial data base with web-based interactive maps allowing access to a global satellite data set to monitor the world's glaciers. The outgrowth of these projects is a strong respect for the needed scientist-to-scientist communication and coordination as well as innovative IT tools. In the coming decades we expect reinforcement of these trends, increasing emphasis on multi-sensor products and multi-disciplinary data sets, all in a rapidly changing IT environment. http://nsidc.org
U23C-1456
Engineering the IOOS: A Conceptual Design and Conceptual Operations Plan
The Integrated Ocean Observing System is the United States component in a world wide effort to provide global coverage of the world's oceans using the Global Ocean Observing System (GOOS). The US contribution includes systems supporting three major IOOS components: the Observation Subsystem, the Modeling and Analysis Subsystem, and the Data Management and Communications (DMAC) Subsystem. The assets to be used in these subsystems include hundreds of existing satellite sensors, buoy arrays, water level monitoring networks, wave monitoring networks, specialized systems for commerce, such as the Physical Oceanographic Real-Time System (PORTSŪ), and health and safety monitoring systems such as NOAA's (National Oceanic and Atmospheric Administration) Harmful Algal Bloom Forecasting System for the Gulf of Mexico. Conceptual design addresses the interconnectivity of these systems, while Conceptual Operations provides understanding of the motivators for interconnectivity and a methodology for how useful products are created and distributed. This paper will report on the conceptual design and the concept of operations devleoped by the authors under contract to NOAA.
U23C-1457
Thirty Years of Continuous Particle Flux Observations in the Deep Sargasso Sea: Looking Back, Looking Forward
The Oceanic Flux Program sediment traps have continuously measured the deep ocean particle flux off Bermuda since the late 1970s, with a >95% temporal coverage at 3200m depth. The early OFP discovery of a seasonal cycle in deep particle flux clearly demonstrated that the deep ocean environment was directly coupled to overlying surface productivity via the particle flux, laying to rest the (then) widely held view of the abyssal ocean as an invariant, largely isolated environment. In the years since, time-series observations of the OFP and others have clearly shown that deep ocean environment is closely linked to upper ocean variability on time-scales of days to decades. The OFP record to date shows that in fact, the deep particle flux- analogous to atmospheric precipitation- follows a strongly skewed (gamma) frequency distribution with transient flux ""rainstorms"" occurring predominately in the late fall and spring periods when surface stratification is weak. On annual time-scales, particle flux is negatively correlated with the wintertime (NDJF) NAO Index. This correlation reflects the greater frequency of transient, high flux events in years when the wintertime NAO Index is low, suggesting a direct influence of increased wintertime storminess. Many causal linkages identified between variability in deep flux and upper ocean forcing off Bermuda have been made possible because of the co-location of two other, complementary observational programs near the OFP mooring: BATS, a ship-based time-series established in 1988 that collects monthly data on upper ocean biogeochemical parameters, and the Bermuda Testbed Mooring (BTM), a platform for moored instrumentation that since 1994 has generated near-continuous data streams on meteorological, physical and bio-optical parameters. In turn, the OFP deep flux record has provided an essential reference point that enables direct evaluation of the biogeochemical consequences of the upper ocean variability observed by BATS and BTM; for example, the influence of mesoscale features that pass through the area. Deep moored sediment traps are a simple, proven and relatively inexpensive technology that provide a unique, spatially integrated, continuous record of the overlying environment. Advances in analytical methods are rapidly expanding our ability to extract ever more detailed oceanographic information from the recovered flux material. As such, deep sediment traps are an invaluable observational component for long-term global ocean observatory networks.
U23C-1458
Towards an Autonomous Global Ocean Carbon Observatory
The ocean is by far the largest carbon reservoir in rapid communication with the atmosphere. Understanding both ocean carbon chemistry and ocean carbon biology are critical for carbon prediction. Marine carbon biomass accounts for roughly 50% of global carbon photosynthesis and a ~10 Pg C/year particulate carbon flux through 100 m into the deep sea. The latter export is commonly referred to as the biological carbon pump. The entire plant biomass of the ocean turns over on week time scales. We lack predictive skill for the biological pump mainly because observations of the biological pump have to be tied to ships which are unable to remain at sea at any location longer than several weeks. Since 2001, a dozen low cost, long lived, robotic Carbon Explorers have been deployed to operate in the ocean for year-long time scales and return real-time information on the daily variation of Particulate Organic Carbon (POC) concentration of the upper 1000 m of the ocean. On June 22 2007 the next generation of Explorer, the Carbon Flux Explorer (CFE) was recovered after a successful two day test and routine operation as deep as 800 m in waters of the San Clemente Basin off shore of San Diego. The CFE represents integration of the Optical Sedimentation Recorder (engineered at Berkeley Laboratory) and the Sounding Ocean Lagrangian Observer (SOLO) profiling float engineered at Scripps. Every eight hours, the CFE surfaced and transmitted in real time engineering and position information in minutes to shore and ship via Iridium satellite link. This fully autonomous and robotic free vehicle/instrument is designed to follow (at hourly resolution) variations of particulate organic and inorganic carbon sedimentation for seasons. Beyond enhanced predictability of the ocean biological carbon pump brought by such enhanced technology, it is fully feasible in the next decade to implement a low cost real-time ocean carbon observing system (a CARBON-ARGO), capable of real time assessment of ocean carbon flux which when coupled with atmospheric CO2 measurements will constrain the balance between carbon emissions and natural and human mediated carbon sinks on land. http://www-ocean.lbl.gov