SF51A-01 08:00h
NASA Earth Science Technology
Many promising remote sensing technologies and systems of space-based observations will be bringing scientific data and observations to Earth scientists in the next 5 to 10 years. These include instruments such as passive and active microwave and optical sensors for measuring geophysical parameters of the atmosphere, the seas and the land masses. Also, advanced information systems will be storing, processing and transmitting data collected from spaced based sensors so that massive amounts of data will be available for scientists to analyze and include in their models. This talk will describe the direction NASA is taking in instrument and information system technology through its investments.
SF51A-02 08:15h
NASA Lidar Technology Program for Earth Science Measurement Applications
Active optical remote sensing (lidar) techniques have provided demonstrable enhancements in spatial resolution and reduced dependence on diurnal cycle in comparison to other remote sensing methods used for Earth science applications. While the versatility of lidar is recognized by its appearance in all of NASA's current Earth science theme roadmaps, there are certain measurements that are uniquely enabled by active optical sensors, e.g., global-scale tropospheric winds and mapping of carbon dioxide sources and sinks, vegetation structure and sub-canopy topography. While the perceived benefit of active optical sensing approaches in advancing high-resolution Earth science measurement objectives is accepted, it has nevertheless become evident that the attendant technologies are insufficiently mature to guarantee an acceptable probability of success in many of the deployment scenarios which are presently envisioned and for which lidar is ideally, if not uniquely, suited. Consequently, a technology risk reduction program has been established to aggressively attack certain key technological gaps and thereby enhance the prospects for future lidar missions. We will review the status of the NASA Earth Science Office's current laser remote sensing missions and describe the principal goals (with respect to both target applications and technology) and recent accomplishments of the laser technology program.
SF51A-03 08:30h
Determination of Sea Ice Thickness from Angular and Frequency Correlation Functions and by Genetic Algorithm: A Theoretical Study of New Instrument Technology
Thickness and extent of Arctic sea ice play a critical role in Earth's climate and ocean circulation. An accurate measurement of these parameters on synoptic scales at regular intervals would enable characterization of this important component for the understanding of ocean circulation and global heat balance. Currently, IceSAT (laser altimeter) and EnviSAT (radar altimeter) and the upcoming CryoSAT (radar altimeter) measurement systems provide estimates of the sea ice freeboard, i.e. that portion of the ice that is above the sea level. The sea ice thickness and changes in thickness are inferred from these measurements. In this paper, we develop the theoretical basis for application of radar interferometry in the VHF band to the direct estimation of sea ice thickness. We employ angular and frequency correlation functions (ACF/FCF) of the electromagnetic wave scattered from sea-ice, using small perturbation and Kirchhoff rough surface scattering and Rayleigh volume scattering models. The medium is modeled as multi-layered stratification consisting of snow, sea ice (including spherical particles of air bubbles and brine inclusions), and sea water. Each surface interface is modeled as a rough surface with a Gaussian roughness spectrum. To characterize the ACF/FCF, the correlation between two waves with different frequencies, incidence and observation angles, is employed, forming a combined spatial- and frequency-domain interferometer. This technique exploits the difference in the correlation properties (phase matching conditions) of surface and volume scattering. The surface correlation function exhibits a strong correlation along a "memory line." The volume scattering shows a strong correlation at specific points - "memory dots." The effect of volume scattering can be suppressed by choosing appropriate combinations of frequencies and angles. The phase of the surface correlation function depends on the scattering geometry (location of the antennas), and provides information about the thickness of the layers. However, the amplitude of the surface ACF/FCF is impacted by the surface roughness characteristics, and reliable ACF/FCF phase information is obtained when its amplitude is sufficiently above the instrument system noise level. Using this aforementioned model, we were able to estimate the sea ice thickness, h, from ACF/FCF. We apply a Genetic Algorithm (GA) to the estimation. The GA method is developed to maximize a fitness function exp(Pm(h)-P(h))2 where P(h) is the phase of ACF/FCF calculated from forward model, and Pm(h) is the measured phase of ACF/FCF- in this case the phase is obtained from simulated forward data using this model. These results show that the sea ice thickness retrieval can be done by the ACF/FCF method. We are currently developing this new instrument technology under the NASA/ESTO instrument incubator program (IIP). We are planning on an Arctic sea ice field experiment from an aircraft in March-April 2005 to validate and improve the inversion model.
SF51A-04 08:45h
On-Board Mining in the Sensor Web
On-board data mining can contribute to many research and engineering applications, including natural hazard detection and prediction, intelligent sensor control, and the generation of customized data products for direct distribution to users. The ability to mine sensor data in real time can also be a critical component of autonomous operations, supporting deep space missions, unmanned aerial and ground-based vehicles (UAVs, UGVs), and a wide range of sensor meshes, webs and grids. On-board processing is expected to play a significant role in the next generation of NASA, Homeland Security, Department of Defense and civilian programs, providing for greater flexibility and versatility in measurements of physical systems. In addition, the use of UAV and UGV systems is increasing in military, emergency response and industrial applications. As research into the autonomy of these vehicles progresses, especially in fleet or web configurations, the applicability of on-board data mining is expected to increase significantly. Data mining in real time on board sensor platforms presents unique challenges. Most notably, the data to be mined is a continuous stream, rather than a fixed store such as a database. This means that the data mining algorithms must be modified to make only a single pass through the data. In addition, the on-board environment requires real time processing with limited computing resources, thus the algorithms must use fixed and relatively small amounts of processing time and memory. The University of Alabama in Huntsville is developing an innovative processing framework for the on-board data and information environment. The Environment for On-Board Processing (EVE) and the Adaptive On-board Data Processing (AODP) projects serve as proofs-of-concept of advanced information systems for remote sensing platforms. The EVE real-time processing infrastructure will upload, schedule and control the execution of processing plans on board remote sensors. These plans provide capabilities for autonomous data mining, classification and feature extraction using both streaming and buffered data sources. A ground-based testbed provides a heterogeneous, embedded hardware and software environment representing both space-based and ground-based sensor platforms, including wireless sensor mesh architectures. The AODP project explores the EVE concepts in the world of sensor-networks, including ad-hoc networks of small sensor platforms.
http://eve.itsc.uah.edu
SF51A-05 09:00h
AFIDS, a Precision Automatic Co-Registration Process for Spacecraft Sensors
AFIDS is the acronym for the Automated Fusion of Image Data System developed recently at JPL under funding from ESTO and other sources, and currently being distributed to interested users in the US government. Automated sub-pixel co-registration and ortho-rectification of satellite imagery is required for precise change detection and analysis of low- (e.g. 1-4km weather satellite), moderate- (e.g. 30m Landsat) and high- resolution (e.g. Ikonos and Quickbird) space sensors. The procedure is "automated" in the sense that human-initiated tiepoint selection is not required, but ephemeris information associated with an image is relied upon to initiate the co-registration process. The methodology employs the additive composition of all pertinent dependent and independent parameters contributing to image-to-image tiepoint misregistration within a satellite scene. Mapping and orthorectification (correction for elevation effects) of satellite imagery defies exact projective solutions because the data are not obtained from a single point (like a camera), but as a continuous process from the orbital path. Standard image processing techniques can apply approximate solutions with sufficient accuracy, but some advances in the state-of-the-art had to be made for precision change-detection and time-series applications where relief offsets become a controlling factor. The basic technique first involves correlation and warping of raw satellite data points to an orthorectified Landsat (30m) or Controlled Image Base (1 or 5m) database to give an approximate mapping. Then digital elevation models are used to correct perspective shifts due to height and view-angle. This image processing approach requires from two (e.g. geosynchronous weather satellite imagery) to four (e.g. polar weather satellite imagery) sequential processing steps that warp the dataset by resampling pixel values. To avoid degradation of the data by multiple resampling, each warp is represented by an ultra-fine grid of tiepoints. For successive warps, the grids are composed mathematically into a single grid such that only one re-sampling occurs. Ultra-fine grids can currently be up to 1000 x 1000, or one million points. Several examples of precision change detection have been undertaken using Hyperion, Advanced Land Imager (ALI), ASTER, NOAA/GOES/VISR, NOAA/POES/AVHRR, MODIS Terra and Aqua, Ikonos, and Quickbird.
SF51A-06 09:15h
Making Sense of Large, Complex Datasets: Using MISR's Multiangle and Multispectral Information to Detect Clouds and Aerosols
Traditional remote sensing is performed using a single, nadir-pointing instrument. Detection of cloud and/or aerosols from such an instrument takes advantage of multiple spectral bands and physically or empirically based thresholds using a number of these bands. The Multiangle Imaging SpectroRadiometer (MISR) instrument currently operational on the Terra satellite offers a unique perspective by obtaining radiance data in four spectral bands using nine cameras with viewing directions ranging from 0 to 70.5 degrees. The MISR dataset presents a challenge to scientists, not only because it requires a shift from the traditional, downward-directed way of viewing the world, but also because, in order to take advantage of the full power of the instrument, new ways must be found to combine and interpret the data. We will describe a variety of methods that have been developed to detect clouds and aerosols using MISR. These methods range from traditional, threshold approaches to techniques which geometrically combine information from MISR's cameras to provide a quasi-three-dimensional view of the world. Most powerfully, machine learning techniques have been applied, specifically Support Vector Machines (SVMs), a cousin to neural networks, that show immense promise in exploiting the full potential of the MISR instrument.
SF51A-07 09:30h
A Web-Based Climatology of Global Ocean Winds
A climatology of winds over the global ocean on a 0.5° x 0.5° grid is under development based on five-years of measurements from the SeaWinds scatterometer. The SeaWinds instrument was launched on 19 June 1999 onboard the QuikSCAT satellite. SeaWinds is an active microwave radar that, using electromagnetic backscatter from the wind roughened ocean surface, measures vector winds with an accuracy equivalent to well-calibrated buoy observations. This five-year climatology is a web-based interactive atlas from which users can retrieve wind statistics, both in tabular and graphic form, for any particular region of interest. The global coverage of the scatterometer data provides valuable information about the wind statistics in the many regions of the world ocean that are sparsely sampled by ships and buoys. One of the anticipated uses of this climatology will be presented via a case study of the NOAA/HAZMAT response to a 2001 oil spill that resulted from the grounding of the tanker "Jessica" at the entrance to Puerto Baquerizo Moreno, in Wreck Bay, on San Cristobal island, Gal pagos.
http://numbat.coas.oregonstate.edu/cogow/
SF51A-08 09:45h
Application of GeoFEST With PYRAMID Mesh Refinement to Southern California Crustal Deformation
Modeling of southern California tectonics with its wide range of length scales, complex faulting pattern and variety of relevant material properties demands high-performance techniques with unprecedented flexibility. The finite element method is a natural choice, but requires special techniques to treat all these features within the bounds of affordable high performance computing. We have demonstrated the parallel scalability of a faulted crust finite element system, GeoFEST. But in three dimensions, element size must be automatically scaled to the local physics. Otherwise extra elements are used, leading to extravagant waste on the order of an inverse-length cubed in memory (and I/O) and at least fourth-power in flops. We apply the PYRAMID parallel adaptive mesh refinement library to generate the needed elements based on an initial coarse mesh, solution, and a strain energy metric. Application to models of the Landers earthquake and the interseismic Los Angeles basin compression highlight the utility and long-range potential of this method for interpreting space geodetic measurements.