U32A-01 INVITED
Global Seismic Monitoring: Past, Present, and Future
Global seismological observations began in April 1889 when an earthquake in Tokyo, Japan was accurately recorded in Germany on two different horizontal pendulum instruments. However, modern global observational seismology really began 46 years ago when the 120-station World Wide Standard Seismograph Network was installed by the US to monitor underground nuclear tests and earthquakes using well-calibrated short- and long- period stations. At the same time rapid advances in computing technology enabled researchers to begin sophisticated analysis of the increasing amount of seismic data, which led to better understanding of earthquake source properties and their use in establishing plate tectonics. Today, global seismic networks are operated by German (Geophon), France (Geoscope), the United States (Global Seismograph Network) and the International Monitoring System. Presently, the Federation of Digital Seismograph Networks registers more than 1,000 broadband stations world-wide, a small percentage of the total number of digital seismic stations around the world. Following the devastating Kobe, Japan and Northridge, California earthquakes, Japan and the US have led the world in the integration of existing seismic sensor systems (weak and strong motion) into development of near-real-time, post-earthquake response products like ShakeMap, detailing the spatial distribution of strong shaking. Future challenges include expanding real-time integration of both seismic and geodetic sensor systems to produce early warning of strong shaking, rapid source determination, as well as near-realtime post- earthquake damage assessment. Seismic network data, hydro-acoustic arrays, deep water tide gauges, and satellite imagery of wave propagation should be integrated in real-time to provide input for hydrodynamic modeling yielding the distribution, timing and size of tsunamis runup--which would then be available instantly on the web, e.g. in a Google Earth format. Dense arrays of strong motion sensors together with deployment of MEMS-type accelerometers in buildings and equipment routinely connected to the Web could potentially provide thousands of measurements of damaging strong ground motion. This technology could ultimately become part of smart building design enabling critical facilities to change their structural response to imminent strong shaking. Looking further forward, it is likely that a continuously observing spaceborne system could image the occurrence of "silent" or "slow" earthquakes as well as the propagation of ground displacement by surface waves at scales of continents.
U32A-02
Medium Resolution Global Earth Observations with Landsat: Looking 35 Years Back and 50 Years Forward
The modern era of global medium resolution satellite remote sensing was inaugurated 35 years ago, in July 1972, with the launch of the first Landsat satellite carrying the Multispectral Scanner (MSS) sensor. Ten years after that first launch, Landsat 4 carried a much-improved sensor aloft, the Thematic Mapper. The TM provided better spatial resolution (30 m versus 79 m) than the MSS, as well as additional spectral bands in the mid- infrared (IR) and thermal IR regions. Roughly another decade later, in April 1999, the Enhanced Thematic Mapper Plus (ETM+) instrument was placed in orbit on Landsat 7. The ETM+ provided a new 15 m panchromatic band and a much-improved thermal band resolution (60 m versus 120 m). Through a combination of planning and good luck, the various Landsat missions have delivered a continuous set of calibrated, multispectral images of the Earth's surface spanning this entire 35-year time period. This imagery database has been used in agricultural evaluations, forest management inventories, geological surveys, water resource estimates, coastal zone appraisals, and a host of other applications to meet the needs of a very broad user community, including business, government, science, education, national security, and now -- even the casual observer -- as Landsat imagery provides the skeletal backbone of Google Earth. Landsat established the U.S. as the world leader in terrestrial remote sensing, contributed significantly to the understanding of the Earth's environment, spawned revolutionary uses of space-based data by the commercial value-added industry, and encouraged a new generation of commercial satellites that provide regional, high-resolution spatial images. In spite of the overall success of the Landsat series of satellites, the first 35 years of the Landsat legacy have been extremely challenging as the push to embrace new technologies was often questioned by those who simply wanted to maintain whatever the current capability was at that point in time. For example, the early days of the TM provided a data rate and storage volume that most users did not have the capability to handle computationally. In addition to these technology-based debates, the Landsat program experienced continuous turmoil and unknowns when it came to the funding and management oversight of each subsequent mission. Following years of debate, in August 2007, the Office of Science and Technology Policy (OSTP) at the White House issued a press release announcing the creation of the National Land Imaging Program (NLIP) to ensure the availability of Landsat class data far into the future. The NLIP is to provide a mechanism within the Interior Department to assess the land imagery needs of federal, state and local land management officials, scientists, and geographic researchers, and to translate those needs into the technical capabilities of future satellites. Thus, continuity of digital image data provided by the Landsat series of satellites looks to be very promising. As stated in the descriptive paragraph for this session, the need for monitoring the Earth is now more acute than ever, and the development and implementation of useful long-term global observations, such as the Landsat series of satellites has provided, is one of the major scientific challenges of our time. We propose to document the lessons learned from Landsat's global observations in recent decades, and to apply these lessons to analysis of current and future needs.
U32A-03
Generating a Long-term Land Data Record from the AVHRR and MODIS Instruments
The goal of the Land Long Term Data Record (LTDR) project is to produce a consistent long term data set from the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments for use in global change and climate studies. The project is prototyping the development and production of a climate quality data record (CDR). LTDR will create daily surface reflectance and normalized difference vegetation index (NDVI) products at a resolution of 0.05°, which is identical to the Climate Modeling Grid (CMG) used for MODIS products from the EOS Terra and Aqua satellites. The AVHRR data begin in June 1981, while the MODIS data start in March 2000 (Terra) and April 2002 (Aqua). The combination of AVHRR and MODIS data will enable the creation of a 26-year data set (1981 - present). The MODIS data record will be extended by the planned Visible/Infrared Imager/Radiometer Suite (VIIRS) instrument on the NPOESS Preparatory Project (NPP) due for launch in 2009. This long-term data record should continue indefinitely. Higher order products such as burned area, land surface temperature, albedo, bidirectional reflectance distribution function (BRDF) correction, leaf area index (LAI), and fraction of photosynthetically active radiation absorbed by vegetation (fPAR), will be created. The LTDR project will reprocess Global Area Coverage (GAC) data from AVHRR sensors onboard NOAA satellites by applying the preprocessing improvements identified in the AVHRR Pathfinder II project and atmospheric and BRDF corrections used in MODIS processing. The preprocessing improvements include radiometric in-flight vicarious calibration for the visible and near infrared channels and inverse navigation to relate an Earth location to each sensor instantaneous field of view (IFOV). Atmospheric corrections for Rayleigh scattering, ozone, and water vapor are undertaken, with aerosol correction being implemented. The LTDR also produces a surface reflectance product for channel 3 (3.75 μ m). Quality assessment (QA) is an integral part of the LTDR production system, which is monitoring temporal trends in the AVHRR products using time-series approaches developed for MODIS land product quality assessment. The land surface reflectance products have been evaluated at AERONET sites. The AVHRR data record from LTDR is also being compared to products from the PAL (Pathfinder AVHRR Land) and GIMMS (Global Inventory Modeling and Mapping Studies) systems to assess the relative merits of this reprocessing vis-à-vis these existing data products. The LTDR products and associated information can be found at http://ltdr.nascom.nasa.gov/ltdr/ltdr.html. http://ltdr.nascom.nasa.gov/ltdr/ltdr.html
U32A-04 INVITED
Global Terrestrial Carbon Observations: Looking 30 Years Back and Maybe 20 Years Forward
Global terrestrial observations have of necessity followed the evolution of polar orbiting satellite technology, and secondarily the computer revolution. The first real measurement of a global terrestrial carbon component was the AVHRR Normalized Difference Vegetation Index record, beginning in 1980. By the mid-1980s the NDVI was being used, with simple global climate statistics to estimate global net primary productivity. The era of the Earth Observing System began in the early 1990s, and featured both better satellite technology and algorithm teams tasked with developing sequential processing code to transform raw observed radiances thru spectral reflectances to biophysical variables such as leaf area index, fraction absorbed photosynthetically active radiation, evapotranspiration and net primary production. EOS datasets now provide a continuous global record of these variables from 2000 – present, with regular validations done from the global array of carbon, water and energy flux tower sites. Future directions will deploy imaging spectrometers, lidar, passive and active microwave sensors and geostationary platforms to enhance global terrestrial carbon monitoring, and more sophisticated algorithm development and parameterization from ground measurement site networks such as Fluxnet.
U32A-05 INVITED
Global and Regional Hydrologic Observations: Looking Back and Ahead
Water resources are central to all aspects of global change; yet we have learned over the past several decades that our ability to understand critical processes and set effective policy depends on our ability to observe and interpret natural hydrologic processes at a wide range of temporal and spatial scales. Until key hydrologic processes and parameters were introduced into climate models, their ability to produce valuable insights was limited. Until long-term historical data, including paleoclimatic data, on precipitation and runoff were collected, water managers and policymakers were unable to make effective decisions about system design and operation; indeed important policy mistakes were made in the absence of this information. Yet important gaps still remain. This talk will review the past century of hydrologic observations in the context of what we've learned, what gaps remain, and what we still need to know in order to manage freshwater resources sustainably and effectively. http://www.pacinst.org
U32A-06
Ready access and utilization of data: Essential ingredients for global observation systems
The anniversary years of 2007-2008 are widely known as the "IGY+50" period. There are several "International Years" that commemorate the IGY and build upon the IGY legacies. Two of the finest of these legacies are the foundation of a global information commons for Earth and space science, and the establishment of the system of World Data Centers. The first legacy finds expression today in the endeavor by the multi-national Group on Earth Observation (GEO) to build an open access Global Earth Observing System of Systems (GEOSS), and efforts such as the "Global Information Commons for Science Initiative" of ICSU's Committee on Data for Science and Technology (CODATA). Ready access to data and data preservation continues to be an essential ingredient for efficient science. There is also the realization that data and information from discipline specific data stores are very useful to investigators who do not work in the narrow discipline areas served by these particular data stores. Evolving data centers are then challenged to provide data and information to non-traditional users, creating new, flexible interfaces to meet their expanding audiences. In the present day, views differ about the future role of the World Data Centers established during IGY and who pays for them. This talk addresses the importance of good data management practices in global observation programs. From the viewpoint of the Electronic Geophysical Year (eGY), the presentation provides the international context for developing interoperability, data sharing capability, and the future of the WDCs.
U32A-07
Documenting Long-term Earth System Evolution With Satellite Observations
Satellite observations play a critical role in documenting earth system evolution, both in terms of characterizing prior and current evolution of the Earth and providing a baseline against which future measurements can be compared. Given that the construction of the necessary long-term data sets requires the use of multiple instruments on multiple platforms, each of which may have their own characteristics, drifts, and degradation, this represents a significant challenge to the scientific community. Over the last 30-or so years, going back to the launch of the Nimbus 7 in 1978, earth scientists learned significant lessons about how to create accurate and stable long-term data records. Sponsoring agencies have tried to capture the lessons and use them as a basis for planning for future systems. This presentation will examine and present future approaches to maximize the quality of the long-term data records produced from earth satellites.
U32A-08
Earth Observations from Space: The First 50 Years of Scientific Achievements
Observing the Earth from space over the last five decades has fundamentally transformed the way people view our home planet. The image of the "blue marble" is taken for granted now, but it was revolutionary when it was first taken in 1972 by the crew on Apollo 17. Since then, the capability to look at Earth from space has grown increasingly sophisticated and evolved from simple photographs to quantitative measurements of Earth properties such as temperature, atmospheric gases, and exact elevation of land and ocean. Consequently, every new method of imaging the Earth from space has resulted in scientific accomplishments that have enabled new discoveries, transformed the field, refined scientific understanding, opened new avenues of research, or provided important societal benefits by improving the predictability of Earth system processes. This National Research Council (NRC) study highlights selected scientific achievements made possible by the first 50 years of Earth satellite observations by space-faring nations. It follows on a recent report from the NRC entitled "Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond" (NRC 2007), also referred to as the "decadal study."