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In France, the level of annoyance in areas around airports is represented by the psyphic index N. Various modifications were proposed in the method of calculating this indexing order to improve the index as an annoyance indicator. The quality of the modified N index as a prognosis index for annoyance caused by aircraft noise is included.
The vertical infrared radiative emitting structure (VIRES) climate index, based on radiative transfer theory and derived from the spectral radiances typically used to retrieve temperature profiles, is introduced. It is assumed that clouds and climate are closely related and a change in one will result in a change in the other. The index is a function of the cloud, temperature, and moisture distributions. It is more accurately retrieved from satellite data than is cloudiness per se. The VIRES index is based upon the shape and relative magnitude of the broadband weighting function of the infrared radiative transfer equation. The broadband weighting curves are retrieved from simulated satellite infrared sounder data (spectral radiances). The retrieval procedure is described and the error error sensitivities of the method investigated. Index measuring options and possible applications of the VIRES index are proposed.
The 2-D difference vegetation index (DVI) and perpendicular vegetation index (PVI), and the 4-D green vegetation index (GVI) are compared in LANDSAT MSS data from grain sorghum (Sorghum bicolor, L. Moench) fields for the years 1973 to 1977. PVI and DVI were more closely related to LAI than was GVI. A new 2-D soil line index (SLI), the vector distance from the soil line origin to the point of intersection of PVI with the soil line, is defined and compared with the 4-D soil brightness index, SBI. SLI (based on MSS and MSS7) and SL16 (based on MSS 5 and MSS 6) were smaller in magnitude than SBI but contained similar information about the soil background. These findings indicate that vegetation and soil indices calculated from the single visible and reflective infrared band sensor systems, such as the AVHRR of the TIROS-N polar orbiting series of satellites, will be meaningful for synoptic monitoring of renewable vegetation.
The 2-D difference vegetation index (DVI) and perpendicular vegetation index (PVI), and the 4-D green vegetation index (GVI) are compared in Landsat MSS data from grain sorghum (Sorghum bicolor, L. Moench) fields for the years 1973 to 1977. PVI and DVI were more closely related to LAI than was GVI. A new 2-D soil line index (SLI), the vector distance from the soil line origin to the point of intersection of PVI with the soil line, is defined and compared with the 4-D soil brightness index, SBI. SLI (based on MSS and MSS7) and SL16 (based on MSS5 and MSS6) were smaller in magnitude than SBI but contained similar information about the soil background. These findings indicate that vegetation and soil indices calculated from the single visible and reflective infrared band sensor systems, such as the AVHRR of the TIROS-N polar orbiting series of satellites, will be meaningful for synoptic monitoring of renewable vegetation. Previously announced in STAR as N83-14567
The utility of MSS spectral indexes for monitoring arid rangeland vegetation was tested by determining correlations between spectral indexes and vegetation parameters and by examining retrospective MSS data to determine if vegetation change could be detected and measured using spectral indexes. MSS Band 5, albedo, and the Kauth-Thomas Brightness component appear to be useful for monitoring total vegetation cover. Multiseasonal green vegetation indexes could be used to estimate changes in the shrub/grass ratio. In retrospective monitoring, spectral index change appeared to be offset from true change, indicating that the methods used to standardize data sets for differences in solar elevation and sensor radiometric response were not completely successful.
This issue of the annual Index to NASA News Releases and Speeches contains a listing of news releases distributed by the Office of Public Affairs, NASA Headquarters, and a selected listing of speeches presented by members of headquarters staff during 1990. The index is arranged in six sections: Subject Index, Personal Names Index, News Release Number Index, Accession Number, Speeches, and New Releases Indices.
On the basis of version 1.0 of the composite MG II solar activity index data set, it is shown that the change in the 27-day running average of the Mg II index from solar maximum to solar minimum is about 8 percent for solar cycle 21 and about 9 percent for solar cycle 22 through January 1992. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets are developed for each instrument to estimate solar variability at mid-UV and near-UV wavelengths. A set of composite scale factors are derived for use with the present composite MG index. Near 205 cm, where solar irradiance variations are important for stratospheric chemistry, the estimated change in irradiance during solar cycle 22 is about 10 +/- 1 percent using the composite Mg II index (version 1.0) and scale factors.
Quantitative assessment of the impact of solar ultraviolet irradiance variations on stratospheric ozone abundances currently requires the use of proxy indicators. The Mg II core-to-wing index has been developed as an indicator of solar UV activity between 175-400 nm that is independent of most instrument artifacts, and measures solar variability on both rotational and solar cycle time scales. Linear regression fits have been used to merge the individual Mg II index data sets from the Nimbus-7, NOAA-9, and NOAA-11 instruments onto a single reference scale. The change in 27-dayrunning average of the composite Mg II index from solar maximum to solar minimum is approximately 8 percent for solar cycle 21, and approximately 9 percent for solar cycle 22 through January 1992. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets have been developed to estimate solar variability at mid-UV and near-UV wavelengths. Near 205 nm, where solar irradiance variations are important for stratospheric photo-chemistry and dynamics, the estimated change in irradiance during solar cycle 22 is approximately 10 percent using the composite Mg II index and scale factors.
The following report details a project design that is to be completed by the end of the year. Determining how engaged a person is at a task is rather difficult. There are many different ways to assess engagement. One such method is to use psychophysical measures. The current study focuses on three determinants of an engagement index proposed by researchers at NASA-Langley (Pope, A. T., Bogart, E. H., and Bartolome, D. S., 1995). The index (20 Beta/(Alpha+Theta)) uses EEG power bands to determine a person's level of engagement while performs a compensatory tracking task. The tracking task switches between manual and automatic modes. Participants each experience both positive and negative feedback within each trial of the three trials. The tracking task is altered in terms of difficulty depending on the participants current engagement index. The rationale of this study is to determine the optimal level of engagement to gain peak performance. The three determinants are based on an absolute index which differs from the past research which uses a slope index.
The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) is the follow-on ocean color instrument to the Coastal Zone Color Scanner (CZCS), which ceased operations in 1986, after an eight-year mission. SeaWiFS was launched on 1 August 1997, on the SeaStar satellite, built by Orbital Sciences Corporation (OSC). The SeaWiFS Project at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC), undertook the responsibility of documenting all aspects of this mission, which is critical to the ocean color and marine science communities. This documentation, entitled the SeaWiFS Technical Report Series, is in the form of NASA Technical Memorandum Number 104566 and 1998-104566. All reports published are volumes within the series. This particular volume, which is the last of the so-called Prelaunch Series serves as a reference, or guidebook, to the previous 42 volumes and consists of 6 sections including: an addenda, an errata, an index to key words and phrases, lists of acronyms and symbols used, and a list of all references cited. The editors have published a cumulative index of this type after every five volumes. Each index covers the reference topics published in all previous editions, that is, each new index includes all of the information contained in the preceding indexes with the exception of any addenda.
This cumulative subject index encompasses the subject indexes of the bibliographies on Chemical Evolution and the Origin of Life that were first published in 1970 and have continued through publication of the 1986 bibliography supplement. Early bibliographies focused on experimental and theoretical material dealing directly with the concepts of chemical evolution and the origin of life, excluding the broader areas of exobiology, biological evolution, and geochemistry. In recent years, these broader subject areas have also been incorporated as they appear in literature searches relating to chemical evolution and the origin of life, although direct attempts have not been made to compile all of the citations in these broad areas. The keyword subject indexes have also undergone an analogous change in scope. Compilers of earlier bibliographies used the most specific term available in producing the subject index. Compilers of recent bibliographies have used a number of broad terms relating to the overall subject content of each citation and specific terms where appropriate. The subject indexes of these 17 bibliographies have, in general, been cumulatively compiled exactly as they originally appeared. However, some changes have been made in an attempt to correct errors, combine terms, and provide more meaningful terms.
Prolonged exposure to weightlessness is known to produce a variety of cardiovascular changes, some of which may influence the astronaut's performance during a mission. In order to find a reliable indicator of cardiovascular adaptation to weightlessness, we analyzed data from nine male subjects after a 24-hour period of normal activity and after a period of simulated weightlessness produced by two hours in a launch position followed by 20 hours of 6 degrees head-down tilt plus pharmacologically induced diuresis (furosemide). Heart rate, arterial pressure, thoracic fluid index, and radial flow were analyzed. Autoregressive spectral estimation and decomposition were used to obtain the spectral components of each variable from the subjects in the supine position during pre- and post-simulated weightlessness. We found a significant decrease in heart rate power and an increase in thoracic fluid index power in the high frequency region (0.2-0.45 Hz) and significant increases in radial flow and arterial pressure powers in the low frequency region (<0.2 Hz) in response to simulated weightlessness. However, due to the variability among subjects, any single variable appeared limited as a dependable index of cardiovascular adaptation to weightlessness. The backward elimination algorithm was then used to select the best discriminatory features from these spectral components. Fisher's linear discriminant and Bayes' quadratic discriminant were used to combine the selected features to obtain an optimal index of adaptation to simulated weightlessness. Results showed that both techniques provided improved discriminant performance over any single variable and thus have the potential for use as an index to track adaptation and prescribe countermeasures to the effects of weightlessness.
Recent studies have revealed strong correlations between 1-10 Hz frequencies of quasiperiodic oscillations (QPOs) and the spectral power law index of several Black Hole (BH) candidate sources when seen in the low/hard state, the steep power-law (soft) state, and in transition between these states. In the soft state these index-QPO frequency correlations show a saturation of the photon index GAMMA approximately equal to 2.7 at high values of the low frequency nu(sub L). This saturation effect was previously identified as a black hole signature. In this paper we argue that this saturation does not occur, at least for one neutron star (NS) source 4U 1728-34, for which the index GAMMA monotonically increases with nu(sub L) to the values of 6 and higher. We base this conclusion on our analysis of approximately 1.5 Msec of RXTE archival data for 4U 1728-34. We reveal the spectral evolution of the Comptonized blackbody spectra when the source transitions from the hard to soft states. The hard state spectrum is a typical thermal Comptonization spectrum of the soft photons which originate in the disk and the NS outer photospheric layers. The hard state photon index is GAMMA approximately 2. The soft state spectrum consists of two blackbody components which are only slightly Comptonized. Thus we can claim (as expected from theory) that in NS sources thermal equilibrium is established for the soft state. To the contrary in BH sources, the equilibrium is never established due to the presence of the BH horizon. The emergent BH spectrum, even in the high/soft state, has a power law component. We also identify the low QPO frequency nu(sub L) as a fundamental frequency of the quasi-spherical component of the transition layer (presumably related to the corona and the NS and disk magnetic closed field lines). The lower frequency nu(sub SL) is identified as the frequency of oscillations of a quasi-cylindrical configuration of the TL (presumably related to the NS and disk magnetic open field lines). We also show that the presence of Fe K(sub alpha), emission-line strengths, QPOs, and the link between them does not depend on radio flux in 4U 1728-34.
We present timing and spectral analysis of approx. 2.2 Ms of Rossi X-ray Time Explorer (RXTE) archival data from Cyg X-1. Using the generic Comptonization model we reveal that the spectrum of Cyg X-1 consists of three components: a thermal seed photon spectrum, a Comptonized part of the seed photon spectrum and the iron line. We find a strong correlation between 0.1-20 Hz frequencies of quasiperiodic oscillations (QPOs) and the spectral power-law index. Presence of two spectral phases (states) are clearly seen in the data when the spectral indices saturate at low and high values of QPO frequencies. This saturation effect was discovered earlier in a number of black hole candidate (BHC) sources and now we strongly confirm this phenomenon in Cyg X-1. In the soft state this index- QPO frequency correlation shows a saturation of the photon index Gamma approx. 2.1 at high values of the low frequency upsilon(sub L). The saturation level of Gamma approx. 2.1 is the lowest value found yet in BHCs. The bolometric luminosity does not show clear correlation with the index. We also show that Fe K(sub alpha) emission line strength (equivalent width, EW) correlates with the QPO frequency. EW increases from 200 eV in the low/hard state to 1.5 keV in the high/soft state. The revealed observational correlations allow us to propose a scenario for the spectral transition and iron line formation which occur in BHC sources. We also present the spectral state (the power-law index) evolution for eight years of Cyg X-1 observations by RXTE.
In order to enable high quality lens designs using N-BK7, BaLKN3, and SF15 at cryogenic temperatures, we have measured the absolute refractive index of prisms of these three materials using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, as a function of both wavelength and temperature. For N-BK7, we report absolute refractive index and thermo-optic coefficient (dn/dT) at temperatures ranging from 50 to 300 K at wavelengths from 0.45 to 2.7 micrometers; for BaLKN3 we cover temperatures ranging from 40 to 300 K and wavelengths from 0.4 to 2.6 micrometers; for SF15 we cover temperatures ranging from 50 to 300 K and wavelengths from 0.45 to 2.6 micrometers. We compare our measurements with others in the literature and provide temperature-dependent Sellmeier coefficients based on our data to allow accurate interpolation of index to other wavelengths and temperatures. While we generally find good agreement (plus or minus 2 x 10(exp -4) for N-BK7, less than 1 x 10(exp -4) for the other materials) at room temperature between our measured values and those provided by the vendor, there is some variation between the datasheets provided with the prisms we measured and the catalog values published by the vendor. This underlines the importance of measuring the absolute refractive index of the material when precise knowledge of the refractive index is required.
We show that a one-component variable-emissivity-spectral-index model (the free- model) provides more physically motivated estimates of dust temperature at the Galactic polar caps than one- or two-component fixed-emissivity-spectral-index models (fixed- models) for interstellar dust thermal emission at far-infrared and millimeter wavelengths. For the comparison we have fit all-sky one-component dust models with fixed or variable emissivity spectral index to a new and improved version of the 210-channel dust spectra from the COBE-FIRAS, the 100-240 micrometer maps from the COBE-DIRBE and the 94 GHz dust map from the WMAP. The best model, the free-alpha model, is well constrained by data at 60-3000 GHz over 86 per cent of the total sky area. It predicts dust temperature (T(sub dust)) to be 13.7-22.7 (plus or minus 1.3) K, the emissivity spectral index (alpha) to be 1.2-3.1 (plus or minus 0.3) and the optical depth (tau) to range 0.6-46 x 10(exp -5) with a 23 per cent uncertainty. Using these estimates, we present all-sky evidence for an inverse correlation between the emissivity spectral index and dust temperature, which fits the relation alpha = 1/(delta + omega (raised dot) T(sub dust) with delta = -.0.510 plus or minus 0.011 and omega = 0.059 plus or minus 0.001. This best model will be useful to cosmic microwave background experiments for removing foreground dust contamination and it can serve as an all-sky extended-frequency reference for future higher resolution dust models.
Leaf Area Index (LAI) is a key variable that bridges remote sensing observations to the quantification of agroecosystem processes. In this study, we assessed the universality of the relationships between crop LAI and remotely sensed Vegetation Indices (VIs). We first compiled a global dataset of 1459 in situ quality-controlled crop LAI measurements and collected Landsat satellite images to derive five different VIs including Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), two versions of the Enhanced Vegetation Index (EVI and EVI2), and Green Chlorophyll Index (CI(sub Green)). Based on this dataset, we developed global LAI-VI relationships for each crop type and VI using symbolic regression and Theil-Sen (TS) robust estimator. Results suggest that the global LAI-VI relationships are statistically significant, crop-specific, and mostly non-linear. These relationships explain more than half of the total variance in ground LAI observations (R2 greater than 0.5), and provide LAI estimates with RMSE below 1.2 m2/m2. Among the five VIs, EVI/EVI2 are the most effective, and the crop-specific LAI-EVI and LAI-EVI2 relationships constructed by TS, are robust when tested by three independent validation datasets of varied spatial scales. While the heterogeneity of agricultural landscapes leads to a diverse set of local LAI-VI relationships, the relationships provided here represent global universality on an average basis, allowing the generation of large-scale spatial-explicit LAI maps. This study contributes to the operationalization of large-area crop modeling and, by extension, has relevance to both fundamental and applied agroecosystem research.
This paper reports measurements of the refractive index of Homosil (Heraeus) over the wavelength range of 0.34-3.16 microns and temperature range of 120-335 K. These measurements were performed by using the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at the NASAs Goddard Space Flight Center. These measurements were in support of an integrated Structural-Thermal-Optical-Performance (STOP) model that was developed for a field-widened Michelson interferometer that is being built and tested for the High Spectral Resolution Lidar (HSRL) project at the NASA Langley Research Center (LaRC). The cryogenic refractive index measurements were required in order to account for the highly sensitivity performance of the HSRL instrument to changes in refractive index with temperature, temperature gradients, thermal expansion, and deformation due to mounting stresses. A dense coverage of the absolute refractive index over the aforementioned wavelength and temperature ranges was used to determine the thermo-optic coefficient (dn/dT) and dispersion relation (dn/d(lamda)) as a function of wavelength and temperature. Our measurements of Homosil will be compared with measurements of other glasses from the fused silica family studied in CHARMS as well as measurements reported elsewhere in literature.