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At least 865 records · Page 48

HP upgrade operational streamlining

New computer technology and resources must be successfully integrated into CDSLR station operations to manage new complex operational tracking requirements, support the on site production of new data products, support ongoing station performance improvements, and to support new station communication requirements. The NASA CDSLR Network is in the process of upgrading station computer resources with HP UNIX workstations, designed to automate a wide range of operational station requirements. The primary HP upgrade objective was to relocate computer intensive data system tasks from the controller computer to a new advanced computer environment designed to meet the new data system requirements. The HP UNIX environment supports fully automated real time data communications, data management, data processing, and data quality control. Automated data compression procedures are used to improve the efficiency of station data communications. In addition, the UNIX environment supports a number of semi-automated technical and administrative operational station tasks. The x window user interface generates multiple simultaneous color graphics displays, providing direct operator visibility and control over a wide range of operational station functions.

Edge, David R.↗

Seasonal budgets of ozone and oxidant precursors in an industrial coastal area of northern Italy

The seasonal budgets and evolution of photochemical oxidants reported for greater Ravenna's urban-industrial area in the present study were calculated using the combined data from on-site systematic surveys (1978-1989) and from the monitoring network of the local environmental authorities. The notable differences in the concentrations of ozone and nitrogen oxides depended on season, and meteorological variables showed a marked correlation to the seasonal budget of trace constituents. The weak local circulation, the land-sea breeze system, and high solar radiation in summer, which may persist at length because of the anticyclonic conditions, can produce episodes of intense photochemical reactions. In winter, by contrast, low solar radiation and the absence of the breeze system results in very different evolutions of both pollutant concentrations and their seasonal budget.

Georgiadis, T.↗

World wide web implementation of the Langley technical report server

On January 14, 1993, NASA Langley Research Center (LaRC) made approximately 130 formal, 'unclassified, unlimited' technical reports available via the anonymous FTP Langley Technical Report Server (LTRS). LaRC was the first organization to provide a significant number of aerospace technical reports for open electronic dissemination. LTRS has been successful in its first 18 months of operation, with over 11,000 reports distributed and has helped lay the foundation for electronic document distribution for NASA. The availability of World Wide Web (WWW) technology has revolutionized the Internet-based information community. This paper describes the transition of LTRS from a centralized FTP site to a distributed data model using the WWW, and suggests how the general model for LTRS can be applied to other similar systems.

Nelson, Michael L.↗

Remote Sensing in Archeology: Classifying Bajos of the Paten, Guatemala

This project focuses on the adaptation of human populations to their environments from prehistoric times to the present. It emphasizes interdisciplinary research to develop ecological baselines through the use of remotely sensed imagery, in situ field work, and the modeling of human population dynamics. It utilizes cultural and biological data from dated archaeological sites to assess the subsistence and settlement patterns of human societies in response to changing climatic and environmental conditions. The utilization of remote sensing techniques in archaeology is relatively new, exciting, and opens many doors.

Lowry, James D., Jr.↗

Atmospheric Limitations to Repeat-Track Radar Interferometry

In its recent radar imaging mission, the Shuttle Imaging Radar satellite (SIR-C) devoted three days to repeat-track interferometry. We have analyzed the data from a test site in the Mojave desert of California. Although good topography ( +/- 10 m on 21 m postings) was obtained, most of the error was caused by turbulent water vapor in the lower atmosphere. Spatial structure of 6 km and all smaller sizes was observed. The RMS, one-way time delay was found to be 0.24 cm. Essentially identical results were obtained at two wavelengths, 24 and 5.7 cm.

Goldstein, Richard↗

BOREAS Forest Cover Data Layers of the NSA in Raster Format

This data set was processed by BORIS staff from the original vector data of species, crown closure, cutting class, and site classification/subtype into raster files. The original polygon data were received from Linnet Graphics, the distributor of data for MNR. In the case of the species layer, the percentages of species composition were removed. This reduced the amount of information contained in the species layer of the gridded product, but it was necessary in order to make the gridded product easier to use. The original maps were produced from 1:15,840-scale aerial photography collected in 1988 over an area of the BOREAS NSA MSA. The data are stored in binary, image format files and they are available from Oak Ridge National Laboratory. The data files are available on a CD-ROM (see document number 20010000884).

Hall, Forrest G.↗

Urban Heat Islands and Summertime Convective Thunderstorms in Atlanta: Three Case Studies

Data from both 27 sites in the Atlanta mesonet surface meteorological network and eight National Weather Service sites were analyzed for the period from 26 July to 3 August 1996. Analysis of the six precipitation events over the city during the period (each on a different day) showed that its urban heat island (UHI) induced a convergence zone that initiated three of the storms at different times of the day, i.e., 0630,0845, and 1445 EDT. Previous analysis has shown that New York City (NYC) effects summer daytime thunderstorm formation and/or movement. That study found that during nearly calm regional flow conditions the NYC UHI initiates convective activity. Moving thunderstorms, however, tended to bifurcate and to move around the city, due to its building barrier effect. The current Atlanta results thus agree with the NYC results with respect to thunderstorm initiation.

Bornstein, Robert↗

Solid Earth and Natural Hazards (SENH) Research and Applications Program and Internation

This is a final report for grant NAG5-8627 entitled 'Joint UNAVCO and JPL proposal to NASA for support of the Solid Earth and Natural Hazards Research and Applications Program and Internation'. This report consists of the following sections: (1) new installations (with site visits); (2) upgrades (with site visits; (3) upcoming upgrades (with site visits); and (4) data management and archive efforts during the performance period.

Source record↗

Validation of Ocean Color Remote Sensing Data using a Moored Databuoy

NASA's Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) aims to measure global ocean color from space to within 5% to provide insights into fundamental ocean processes. SeaWiFS must be backed by comprehensive calibration and validation programs if the mission is to achieve this. In situ measurements of normalized water-leaving radiance (L(sub wn)) made simultaneously with satellite measurements can complement on-orbit methods of tracking changes in the calibration of the satellite radiometer and allow end-to-end vicarious validation of the remotely-sensed data. A moored optical databuoy was developed at Plymouth Marine Laboratory, UK to measure L(sub wn) in the western English Channel. Tests indicate that the buoy is capable of measuring spectral incident irradiance with less than 10% error and water-leaving radiance with less than 20% error; these errors are reduced by averaging and show no bias. There were 24 match-ups with good quality SeaWiFS data at the buoy site during the ten months of deployment within the period May 1997 and September 1998. The differences between the buoy and SeaWiFS measurements of L(sub wn) were found to be variable and often large. The root-mean-square (RMS) differences varied from 102% at 412 nm to 50% at 555 nm. The RMS differences in measurements of L(sub wn) could be reduced to less than 18% by a combination of increasing the calibration coefficients of SeaWiFS by between 0.2 and 4.3% in the visible bands and by tuning the extrapolation of aerosol radiances from the near infrared to the visible wavelengths. These results imply that the monitoring of the absolute calibration of the SeaWiFS bands is imperfect and errors remain in the extrapolation of aerosol radiances for atmospheric correction.

Lavender, Samantha↗

Climate Controls on Carbon Sequestration in Eastern North America

Mid-latitude forest ecosystems have been proposed as a "missing sink" today. The role of soils (including wetlands) in this proposed sink is a very important unknown. In order to make estimates of future climate change effects on carbon storage, we can examine past wetland carbon sequestration. How did past climate change affect net wetland carbon storage? We present long-term data from existing wetland sites used for paleoclimate reconstruction to assess the net carbon storage in wetland over the last 15000 years. During times of colder and wetter climate, many mid-latitude sites show increases in carbon storage, while past warmer, drier climates produced decreases in storage. Comparison among bog, fen, swamp, and tidal marsh are demonstrated for the Hudson Valley region.

Peteet, D. M.↗

Tropical Rainfall Measuring Mission (TRMM)

Contents include the following: 1. Hurricane Isabel. TRMM composite images of Hurricane Isabel. TRMM application to monitoring potential floods. 2.TRMM Orbit and Instruments. TRMM Ground Track for 35" Orbit With Ground Truth Verification Sites. 3. TRMM Science Data Products at the GES DAAC. 4. TRMM Data Access and Services at GES DAAC. TRMM Online Visualization and Analysis System. Selected Recent TRMM Data Applications From Around the World.

Rui, Hualan↗

LSCC Apollo and Luna Soil Analyses: Update of Soil Evolution Model

The Lunar Soil Characterization Consortium (LSCC) has obtained samples of Luna 16, 20 and 24 soils. Although these particular samples encountered contamination during processing, preliminary results are consistent with previous integrated analyses and expand the soil data to three additional sites.

Pieters, C. M.↗

Bio-Optical and Remote Sensing Observations in Chesapeake Bay

The high temporal and spatial resolution of satellite ocean color observations will prove invaluable for monitoring the health of coastal ecosystems where physical and biological variability demands sampling scales beyond that possible by ship. However, ocean color remote sensing of Case 2 waters is a challenging undertaking due to the optical complexity of the water. The focus of this SIMBIOS support has been to provide in situ optical measurements from Chesapeake Bay (CB) and adjacent mid-Atlantic bight (MAB) waters for use in algorithm development and validation efforts to improve the satellite retrieval of chlorophyll (chl a) in Case 2 waters. CB provides a valuable site for validation of data from ocean color sensors for a number of reasons. First, the physical dimensions of the Bay (> 6,500 km2) make retrievals from satellites with a spatial resolution of approx. 1 km (i.e., SeaWiFS) or less (i.e., MODIS) reasonable for most of the ecosystem. Second, CB is highly influenced by freshwater flow from major rivers, making it a classic Case 2 water body with significant concentrations of chlorophyll, particulates and chromophoric dissolved organic matter (CDOM) that highly impact the shape of reflectance spectra.

Harding, Lawrence W., Jr.↗

Relief Evolution in Tectonically Active Mountain Ranges

The overall aims of this 3-yr project, as originally proposed were to: (1) investigate quantitatively the roles of fluvial and glacial erosion in the evolution of relief in mountainous regions, and (2) test rigorously the quality and accuracy of SRTM topographic data in areas of rugged relief - both the most challenging and of greatest interest to geomorphic, neotectonic, and hazards applications. Natural laboratories in both the western US and the Southern Alps of New Zealand were identified as most promising. The project has been both successful and productive, despite the fact that no SRTM data for our primary field sites in New Zealand were released on the time frame of the work effort. Given the delayed release of SRTM data, we pursued the scientific questions of the roles of fluvial and, especially, glacial erosion in the evolution of relief in mountainous regions using available digital elevation models (DEMs) for the Southern Alps of New Zealand (available at both 25m and 50m pixel sizes), and USGS 10m and 30m DEMs within the Western US. As emphasized in the original proposal, we chose the emphasis on the role of glacial modification of topographic relief because there has been little quantitative investigation of glacial erosion processes at landscape scale. This is particularly surprising considering the dramatic sculpting of most mid- and high-latitude mountain ranges, the prodigious quantities of glacially-derived sediment in terrestrial and marine basins, and the current cross-disciplinary interest in the role of denudational processes in orogenesis and the evolution of topography in general. Moreover, the evolution of glaciated landscapes is not only a fundamental problem in geomorphology in its own right, but also is at the heart of the debate over Late Cenozoic linkages between climate and tectonics.

Whipple, Kelin X.↗

Bion 11 mission: primate experiments

A summary is provided of the major operations required to conduct the wide range of primate experiments on the Bion 11 mission, which flew for 14 days beginning December 24, 1996. Information is given on preflight preparations, including flight candidate selection and training; attachment and implantation of bioinstrumentation; flight and ground experiment designs; onboard life support and test systems; ground and flight health monitoring; flight monkey selection and transport to the launch site; inflight procedures and data collection; postflight examinations and experiments; and assessment of results.

NASA Discipline Musculoskeletal↗

Corrosion Study Using Electrochemical Impedance Spectroscopy

Corrosion is a common phenomenon. It is the destructive result of chemical reaction between a metal or metal alloy and its environment. Stainless steel tubing is used at Kennedy Space Center for various supply lines which service the orbiter. The launch pads are also made of stainless steel. The environment at the launch site has very high chloride content due to the proximity to the Atlantic Ocean. Also, during a launch, the exhaust products in the solid rocket boosters include concentrated hydrogen chloride. The purpose of this project was to study various alloys by Electrochemical Impedance Spectroscopy in corrosive environments similar to the launch sites. This report includes data and analysis of the measurements for 304L, 254SMO and AL-6XN in primarily neutral 3.55% NaCl. One set of data for 304L in neutral 3.55%NaCl + 0.1N HCl is also included.

Farooq, Muhammad Umar↗

Evaluation and Validation of Case 2 Algorithms in Chesapeake Bay

The high temporal and spatial resolution of satellite ocean color observations will prove invaluable for monitoring the health of coastal ecosystems where physical and biological variability demands sampling scales beyond that possible by ship. However, ocean color remote sensing of Case 2 waters is a challenging undertaking due to the optical complexity of the water. The focus of this SIMBIOS support has been to provide in situ optical measurements form Chesapeake Bay (CB) and adjacent mid-Atlantic bight (MAB) waters for use in algorithm development and validation efforts to improve the satellite retrieval of chlorophyll (chl a) in Case 2 waters. CB provides a valuable site for validation of data from ocean color sensors for a number of reasons. First, the physical dimensions of the Bay (greater than 6,500 square kilometers) make retrievals from satellites with a spatial resolution of approximately 1 kilometer (i.e., SeaWiFS) or less (i.e., MODIS) reasonable for most of the ecosystem. Second, CB is highly influenced by freshwater flow from major rivers, making it a classic Case 2 water body with significant concentrations of chlorophyll, particulates and chromophoric dissolved organic matter (CDOM) that highly impact the shape of reflectance spectra. Finally, past and ongoing research efforts provided an expensive data set of optical observations that support the goal of this project.

Harding, Lawrence W., Jr.↗

Lower Thermospheric Composition Studies in the Auroral Zone

This TIMED/CEDAR grant had two major objectives. The GUVI instrument on TIMED should routinely produces maps of the flux of energetic particles and their average energy. However, while those data will be available soon there were no plans to routinely produce the O/N2 ratio in the auroral. Ground-based photometric techniques have been available for years which routinely measure all three quantities in the auroral zone. The first objective of the previous proposal was to use these ground-based techniques to provide some validation for the routine measure of average energy. The second objective was to use the ground-based to data to validate GUVI algorithms for the measure of O/N2 in the auroral zone. We have made some progress to these goals while we await the release of the properly precessed GUVI data. For now these objectives are being addressed by making use of algorithms by one of us (Doug Strickland of CPI) that are being used for specific GUVI level 1B data sets that contain data coincident with the groundbased measurements. Also we have collected ground-based data from two Alaska sites and they are available on our web site and on the CEDAR website. The details of the progress we have made are discussed.

Hecht, James↗