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Sample records for albedo thermal inertia

  1. Atmospheric effects on the mapping of Martian thermal inertia and thermally derived albedo

    NASA Technical Reports Server (NTRS)

    Hayashi, Joan N.; Jakosky, Bruce M.; Haberle, Robert M.

    1995-01-01

    We examine the effects of a dusty CO2 atmosphere on the thermal inertia and thermally derived albedo of Mars and we present a new map of thermal inertias. This new map was produced using a coupled surface atmosphere (CSA) model, dust opacities from Viking infrared thermal mapper (IRTM) data, and CO2 columns based on topography. The CSA model thermal inertias are smaller than the 2% model thermal inertias, with the difference largest at large thermal inertia. Although the difference between the thermal inertias obtained with the two models is moderate for much of the region studied, it is largest in regions of either high dust opacity or of topographic lows, including the Viking Lander 1 site and some geologically interesting regions. The CSA model thermally derived albedos do not acurately predict the IRTM measured albedos and are very similar to the thermally derived albedos obtained with models making the 2% assumption.

  2. Atmospheric effects on the mapping of Martian thermal inertia and thermally derived albedo

    NASA Technical Reports Server (NTRS)

    Hayashi, Joan N.; Jakosky, Bruce M.; Haberle, Robert M.

    1995-01-01

    We examine the effects of a dusty C02 atmosphere on the thermal inertia and thermally derived albedo of Mars and we present a new map of thermal inertias. This new map was produced using a coupled surface atmosphere (CSA) model, dust opacities from Viking infrared thermal mapper (IRTM) data, and C02 columns based on topography. The CSA model thermal inertias are smaller than the 2% model thermal inertias, with the difference largest at large thermal inertia. Although the difference between the thermal inertias obtained with the two models is moderate for much of the region studied, it is largest in regions of either high dust opacity or of topographic lows, including the Viking Lander 1 site and some geologically interesting regions. The CSA model thermally derived albedos do not accurately predict the IRTM measured albedos and are very similar to the thermally derived albedos obtained with models making the 2% assumption.

  3. Atmospheric effects on the mapping of Martian thermal inertia and thermally derived albedo

    NASA Technical Reports Server (NTRS)

    Hayashi, J. N.; Jakosky, B. M.; Haberle, R. M.

    1994-01-01

    The most widely used thermal inertia data for Mars assumes the atmospheric contribution is constant and equal to 2 percent of the maximum solar insolation. Haberle and Jakosky investigated the effect of including a dusty CO2 atmosphere and sensible heat exchange with the surface on thermal inertia. We recently utilized Haberle and Jakosky's coupled surface-atmosphere model to investigate the effects of such an atmosphere on the thermally derived albedo. The thermally derived albedo is the albedo which, together with the thermal inertia, provides model surface temperatures which best match the observed temperatures. New maps are presented of thermal inertia and thermally derived albedo which incorporate dust opacities derived from IRTM data.

  4. Albedo, thermal inertia and rotation of ring particles (Invited)

    NASA Astrophysics Data System (ADS)

    Morishima, R.; Spilker, L. J.; Ohtsuki, K.; Cassini Cirs Ring Team

    2010-12-01

    Since the Saturn orbit insertion of the Cassini spacecraft in mid-2004 up to now, the Cassini composite infrared spectrometer (CIRS) has measured temperatures of Saturn's main rings at various observational geometries. We present results of parameter fits using our new thermal model (Morishima et al. 2009). Our model is based on classical radiative transfer and takes into account the heat transport due to particle motion in the azimuthal and vertical directions. The model assumes a bimodal size distribution consisting of small fast rotators and large slow rotators. Important parameters are the Bolometric bond albedo, A_V, the fraction of fast rotators in cross section, f_fast, and the thermal inertia, Γ. Two different data sets are used to estimate these parameters. The first set, which consists of four radial scans obtained at low and high solar phases both on the lit and unlit faces of rings (Spilker et al. 2006), is suitable for accurate estimations of A_V and f_fast with high radial resolution. Another one, which consists of azimuthal scans that include data in Saturn shadow (Leyrat et al. 2008), is suitable for estimations of Γ. The estimated parameters are shown in Fig.1. The albedo is 0.1-0.4, 0.5-0.7, 0.4, 0.5 for the C ring, the B ring, the Cassini division, and the A ring, respectively. The fraction of fast rotators is roughly half for all the rings. The thermal inertia is 7-21 in MKS units. For the mid B ring, values of parameters obtained from two data sets are consistent with each other if ring particles are assumed to bounce at the midplane due to mutual collisions. We also find that fits to azimuthal scans are improved if Γ for fast rotators is larger than that for slow rotators. Albedo, fraction of fast rotators in cross section, and thermal inertia estimated from parameter fits. Two different thermal data sets are used: radial scans at four different geometries (solid curves) and azimuthal scans including data in Saturn shadow (diamonds). Dashed

  5. Parameterization of albedo, thermal inertia, and surface roughness of desert scrub/sandy soil surface

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Mccumber, M.

    1986-01-01

    Spectral albedo, A sub n, for the direct solar beam is defined as A sub n (r sub i,s, theta sub 0) = r sub i exp(-s tan theta sub 0)1-I(s) where I(s) is the integral over all reflection angles describing the interception by the absorbing plants of the flux reflected from the soil, r sub i soil reflectance, assumed Lambertian, S the projection on a vertical plane of plants per unit surface area, and theta sub 0 is the solar zenith angle. Hemispheric reflectance for the direct solar beam equals 1-I(s) times the reflectance to the zenith. The values of s of 0.1, 0.2, and 0.3 respectively quantify sparse, moderately dense, and very dense desert scrub. Thin plants are assumed to be of negligible thermal inertia, and thus directly yield the absorbed insolation to the atmosphere. Surface thermal inertia is therefore effectively reduced. The ratio of surface roughness height to plant height is parameterized for sparse, moderately dense, and very dense desert-scrub as a function of s based on data expressing the dependence of this ratio on plant silhouette.

  6. Mars Thermal Inertia

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image shows the global thermal inertia of the Martian surface as measured by the Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor. The data were acquired during the first 5000 orbits of the MGS mapping mission. The pattern of inertia variations observed by TES agrees well with the thermal inertia maps made by the Viking Infrared Thermal Mapper experiment, but the TES data shown here are at significantly higher spatial resolution (15 km versus 60 km).

    The TES instrument was built by Santa Barbara Remote Sensing and is operated by Philip R. Christensen, of Arizona State University, Tempe, AZ.

  7. Novel method of thermal-inertia determination

    NASA Astrophysics Data System (ADS)

    MacLennan, E.; Emery, J.

    2014-07-01

    makes it possible to accurately constrain the surface temperature distribution of an asteroid, and thus thermal inertia, without knowing an object's spin axis. To test the validity of this method we select objects that have previous spin axis and shape information from the DAMIT website [4] and estimate thermal inertia using both the traditional and multi-epoch method. We present thermal inertia, size and albedo results for over a dozen such objects observed by WISE and compare to previous thermal inertia estimates of other objects. The future application of this method to asteroids with undetermined spin axes is sure to dramatically increase the number of asteroid thermal-inertia estimates.

  8. Thermal Inertia of Rocks and Rock Populations

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Jakosky, B. M.; Mellon, M. T.

    2001-01-01

    The effective thermal inertia of rock populations on Mars and Earth is derived from a model of effective inertia versus rock diameter. Results allow a parameterization of the effective rock inertia versus rock abundance and bulk and fine component inertia. Additional information is contained in the original extended abstract.

  9. High-Resolution Thermal Inertia Mapping from the Mars Global Surveyor Thermal Emission Spectrometer

    USGS Publications Warehouse

    Mellon, M.T.; Jakosky, B.M.; Kieffer, H.H.; Christensen, P.R.

    2000-01-01

    High-resolution thermal inertia mapping results are presented, derived from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) observations of the surface temperature of Mars obtained during the early portion of the MGS mapping mission. Thermal inertia is the key property controlling the diurnal surface temperature variations, and is dependent on the physical character of the top few centimeters of the surface. It represents a complex combination of particle size, rock abundance, exposures of bedrock, and degree of induration. In this work we describe the derivation of thermal inertia from TES data, present global scale analysis, and place these results into context with earlier work. A global map of nighttime thermal-bolometer-based thermal inertia is presented at 14?? per pixel resolution, with approximately 63% coverage between 50??S and 70??N latitude. Global analysis shows a similar pattern of high and low thermal inertia as seen in previous Viking low-resolution mapping. Significantly more detail is present in the high-resolution TES thermal inertia. This detail represents horizontal small-scale variability in the nature of the surface. Correlation with albedo indicates the presence of a previously undiscovered surface unit of moderate-to-high thermal inertia and intermediate albedo. This new unit has a modal peak thermal inertia of 180-250 J m-2 K-1 s-12 and a narrow range of albedo near 0.24. The unit, covering a significant fraction of the surface, typically surrounds the low thermal inertia regions and may comprise a deposit of indurated fine material. Local 3-km-resolution maps are also presented as examples of eolian, fluvial, and volcanic geology. Some impact crater rims and intracrater dunes show higher thermal inertias than the surrounding terrain; thermal inertia of aeolian deposits such as intracrater dunes may be related to average particle size. Outflow channels and valleys consistently show higher thermal inertias than the

  10. Global Surface Thermal Inertia Derived from Dawn VIR Observations

    NASA Astrophysics Data System (ADS)

    Titus, T. N.; Becker, K. J.; Anderson, J.; Capria, M.; Tosi, F.; Prettyman, T. H.; De Sanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.; McCord, T. B.; Li, J. Y.; Russell, C. T.; Raymond, C. A.

    2012-12-01

    Comparisons of surface temperatures, derived from Dawn [1] Visible and Infrared Mapping Spectrometer (VIR-MS) [2] observations , to thermal models suggest that Vesta generally has a low-thermal-inertia surface, between 25 and 35 J m^-2 K^-1 s^-½, consistent with a thick layer of fine-grain material [3]. Temperatures were calculated using a Bayesian approach to nonlinear inversion as described by Tosi et al. [4]. In order to compare observed temperatures of Vesta to model calculations, several geometric and photometric parameters must be known or estimated. These include local mean solar time, latitude, local slope, bond bolometric albedo, and the effective emissivity at 5μm. Local time, latitude, and local slope are calculated using the USGS ISIS software system [5]. We employ a multi-layered thermal-diffusion model called 'KRC' [6], which has been used extensively in the study of Martian thermophysical properties. This thermal model is easily modified for use with Vesta by replacing the Martian ephemeris input with the Vesta ephemeris and disabling the atmosphere. This model calculates surface temperatures throughout an entire Vesta year for specific sets of slope, azimuth, latitude and elevation, and a range of albedo and thermal-inertia values. The ranges of albedo and thermal inertia values create temperature indices that are closely matched to the dates and times observed by VIR. Based on observed temperatures and best-fit KRC thermal models, estimates of the annual mean surface temperatures were found to range from 176 K - 188 K for flat zenith-facing equatorial surfaces, but these temperatures can drop as low as 112 K for polar-facing slopes at mid-latitudes. [7] In this work, we will compare observed temperatures of the surface of Vesta (using data acquired by Dawn VIR-MS [2] during the approach, survey, high-altitude mapping and departure phases) to model temperature results using the KRC thermal model [5]. Where possible, temperature observations from

  11. Investigating asteroid surface thermal inertias with NEOWISE

    NASA Astrophysics Data System (ADS)

    Nugent, C.; Mainzer, A.; Masiero, J.; Lysek, M.; Grav, T.; Bauer, J.; Cutri, R.; Wright, E.

    2014-07-01

    NEOWISE, the asteroid-hunting mission that employs the Wide-field Infrared Survey Explorer (WISE) spacecraft, has observed over 150,000 minor planets over four infrared wavelength bands (Mainzer et al. 2011). Several of these asteroids have also been observed by radar, and have associated shapes and spin states (e.g., Busch et al. 2011, see current list maintained by L. Benner at http://echo.jpl.nasa.gov/˜lance/shapes/ asteroid_shapes.html). We combine these datasets via thermophysical modeling, a technique that combines 3-D asteroid shapes, a model of heat transport, and infrared observations to determine the thermal inertia of an asteroid (e.g., Leyrat et al. 2011). Thermal inertia measurements can constrain regolith composition and density, which can be linked to collisional history and dynamical evolution. Measurements of thermal conductivity and heat capacity (components of thermal inertia), can refine predictions of the Yarkovsky drift, a non-gravitational force that can change asteroid orbits (Bottke et al. 2006). We present thermal inertia measurements derived from the NEOWISE dataset, such as surface thermal inertia measurements of 2008 EV5 (see figure).

  12. The thermal inertia of Mars from the Mars Global Surveyor Thermal Emission Spectrometer

    USGS Publications Warehouse

    Jakosky, Bruce M.; Mellon, Michael T.; Kieffer, Hugh H.; Christensen, Philip R.; Varnes, E. Stacy; Lee, Steven W.

    2000-01-01

    We have used Mars Global Surveyor (MGS) Thermal Emission Spectrometer thermal emission measurements to derive the thermal inertia of the Martian surface at the ∼100-km spatial scale. We have validated the use of nighttime-only measurements to derive thermal inertia as well as the use of a single wavelength band versus bolometric thermal emission measurements. We have also reanalyzed the Viking Infrared Thermal Mapper data set in a similar manner in order to allow a direct comparison between the two. Within the uncertainties of the fit of the data to the model, and the uncertainties inherent in the model, the thermal inertia has not changed substantially in the 21 years between the Viking and the MGS measurements. Although some differences are seen, they are most likely due to changes in albedo during the intervening years or to residual effects of airborne dust that are not fully accounted for in the thermal models. The thermal inertia values that we derive, between about 24 and 800 J m-2 s-1/2 K-1, are thought to better represent the actual thermal inertia of the Martian surface than previous estimates.

  13. Geologic applications of thermal-inertia mapping from satellite. [Powder River Basin, Wyoming

    NASA Technical Reports Server (NTRS)

    Offield, T. W. (Principal Investigator); Miller, S. H.; Watson, K.

    1979-01-01

    The author has identified the following significant results. After digitization, a noise rejection filter was applied to data obtained by USGS aircraft. An albedo image was formed by combining three bands of visible data. Along with the day and nighttime thermal data, the albedo image was used to construct a relative thermal-inertia image. This image, registered to a topographic base, shows there are thermal property differences in the vicinity of the contact between the Fort Union and Wasatch formations in the Powder River Basin, Wyoming.

  14. Thermal mapping of mountain slopes on Mars by application of a Differential Apparent Thermal Inertia technique

    NASA Astrophysics Data System (ADS)

    Kubiak, Marta; Mège, Daniel; Gurgurewicz, Joanna; Ciazela, Jakub

    2015-04-01

    Thermal inertia (P) is an important property of geologic surfaces that essentially describes the resistance to temperature (T) change as heat is added. Most remote sensing data describe the surface only. P is a volume property that is sensitive to the composition of the subsurface, down to a depth reached by the diurnal heating wave. As direct measurement of P is not possible on Mars, thermal inertia models (Fergason et al., 2006) and deductive methods (the Apparent Thermal Inertia: ATI and Differential Apparent Thermal Inertia: DATI) are used to estimate it. ATI is computed as (1 - A) / (Tday - Tnight), where A is albedo. Due to the lack of the thermal daytime images with maximum land surface temperature (LST) and nighttime images with minimum LST in Valles Marineris region, the ATI method is difficult to apply. Instead, we have explored the DATI technique (Sabol et al., 2006). DATI is calculated based on shorter time (t) intervals with a high |ΔT/Δt| gradient (in the morning or in the afternoon) and is proportional to the day/night temperature difference (ATI), and hence P. Mars, which exhibits exceptionally high |ΔT/Δt| gradients due to the lack of vegetation and thin atmosphere, is especially suitable for the DATI approach. Here we present a new deductive method for high-resolution differential apparent thermal inertia (DATI) mapping for areas of highly contrasted relief (e.g., Valles Marineris). Contrary to the thermal inertia models, our method takes local relief characteristics (slopes and aspects) into account. This is crucial as topography highly influences A and ΔT measurements. In spite of the different approach, DATI values in the flat areas are in the same range as the values obtained by Fergason et al. (2006). They provide, however, more accurate information for geological interpretations of hilly or mountainous terrains. Sabol, D. E., Gillespie, A. R., McDonald, E., and Danilina, I., 2006. Differential Thermal Inertia of Geological Surfaces. In

  15. Delamination detection in reinforced concrete using thermal inertia

    SciTech Connect

    Del Grande, N K; Durbin, P F

    1998-11-30

    We investigated the feasibility of thermal inertia mapping for bridge deck inspections. Using pulsed thermal imaging, we heat-stimulated surrogate delaminations in reinforced concrete and asphalt-concrete slabs. Using a dual-band infrared camera system, we measured thermal inertia responses of Styrofoam implants under 5 cm of asphalt, 5 cm of concrete, and 10 cm of asphalt and concrete. We compared thermal maps from solar-heated concrete and asphalt-concrete slabs with thermal inertia maps from flash-heated concrete and asphalt-concrete slabs. Thermal inertia mapping is a tool for visualizing and quantifying subsurface defects. Physically, thermal inertia is a measure of the resistance of the bridge deck to temperature change. Experimentally, it is determined from the inverse slope of the surface temperature versus the inverse square root of time. Mathematically, thermal inertia is the square root of the product of thermal conductivity, density, and heat capacity. Thermal inertia mapping distinguishes delaminated decks which have below-average thermal inertias from normal or shaded decks. Key Words: Pulsed Thermal Imaging, Thermal Inertia, Detection Of Concrete Bridgedeck Delaminations

  16. Delamination detection in reinforced concrete using thermal inertia

    NASA Astrophysics Data System (ADS)

    DelGrande, Nancy; Durbin, Philip F.

    1999-02-01

    We investigated the feasibility of thermal inertia mapping for bridge deck inspections. Using pulsed thermal imaging, we heat-stimulated surrogate delaminations in reinforced concrete and asphalt-concrete slabs. Using a dual-band infrared camera system, we measured thermal inertia responses of Styrofoam implants under 5 cm of asphalt, 5 cm of concrete, and 10 cm of asphalt and concrete. We compared thermal maps from solar-heated concrete and asphalt-concrete slabs with thermal inertia maps from flash-heated concrete and asphalt-concrete slabs. Thermal inertia mapping is a tool for visualizing and quantifying subsurface defects. Physically, thermal inertia is a measure of the resistance of the bridge deck to temperature change. Experimentally, it is determined from the inverse slope of the surface temperature versus the inverse square root of time. Mathematically, thermal inertia is the square root of the product of thermal conductivity, density, and heat capacity. Thermal inertia mapping distinguishes delaminated decks which have below-average thermal inertias from normal or shaded decks.

  17. THERMAL PHASES OF EARTH-LIKE PLANETS: ESTIMATING THERMAL INERTIA FROM ECCENTRICITY, OBLIQUITY, AND DIURNAL FORCING

    SciTech Connect

    Cowan, Nicolas B.; Voigt, Aiko; Abbot, Dorian S.

    2012-09-20

    In order to understand the climate on terrestrial planets orbiting nearby Sun-like stars, one would like to know their thermal inertia. We use a global climate model to simulate the thermal phase variations of Earth analogs and test whether these data could distinguish between planets with different heat storage and heat transport characteristics. In particular, we consider a temperate climate with polar ice caps (like the modern Earth) and a snowball state where the oceans are globally covered in ice. We first quantitatively study the periodic radiative forcing from, and climatic response to, rotation, obliquity, and eccentricity. Orbital eccentricity and seasonal changes in albedo cause variations in the global-mean absorbed flux. The responses of the two climates to these global seasons indicate that the temperate planet has 3 Multiplication-Sign the bulk heat capacity of the snowball planet due to the presence of liquid water oceans. The obliquity seasons in the temperate simulation are weaker than one would expect based on thermal inertia alone; this is due to cross-equatorial oceanic and atmospheric energy transport. Thermal inertia and cross-equatorial heat transport have qualitatively different effects on obliquity seasons, insofar as heat transport tends to reduce seasonal amplitude without inducing a phase lag. For an Earth-like planet, however, this effect is masked by the mixing of signals from low thermal inertia regions (sea ice and land) with that from high thermal inertia regions (oceans), which also produces a damped response with small phase lag. We then simulate thermal light curves as they would appear to a high-contrast imaging mission (TPF-I/Darwin). In order of importance to the present simulations, which use modern-Earth orbital parameters, the three drivers of thermal phase variations are (1) obliquity seasons, (2) diurnal cycle, and (3) global seasons. Obliquity seasons are the dominant source of phase variations for most viewing angles. A

  18. Thermal Phases of Earth-like Planets: Estimating Thermal Inertia from Eccentricity, Obliquity, and Diurnal Forcing

    NASA Astrophysics Data System (ADS)

    Cowan, Nicolas B.; Voigt, Aiko; Abbot, Dorian S.

    2012-09-01

    In order to understand the climate on terrestrial planets orbiting nearby Sun-like stars, one would like to know their thermal inertia. We use a global climate model to simulate the thermal phase variations of Earth analogs and test whether these data could distinguish between planets with different heat storage and heat transport characteristics. In particular, we consider a temperate climate with polar ice caps (like the modern Earth) and a snowball state where the oceans are globally covered in ice. We first quantitatively study the periodic radiative forcing from, and climatic response to, rotation, obliquity, and eccentricity. Orbital eccentricity and seasonal changes in albedo cause variations in the global-mean absorbed flux. The responses of the two climates to these global seasons indicate that the temperate planet has 3× the bulk heat capacity of the snowball planet due to the presence of liquid water oceans. The obliquity seasons in the temperate simulation are weaker than one would expect based on thermal inertia alone; this is due to cross-equatorial oceanic and atmospheric energy transport. Thermal inertia and cross-equatorial heat transport have qualitatively different effects on obliquity seasons, insofar as heat transport tends to reduce seasonal amplitude without inducing a phase lag. For an Earth-like planet, however, this effect is masked by the mixing of signals from low thermal inertia regions (sea ice and land) with that from high thermal inertia regions (oceans), which also produces a damped response with small phase lag. We then simulate thermal light curves as they would appear to a high-contrast imaging mission (TPF-I/Darwin). In order of importance to the present simulations, which use modern-Earth orbital parameters, the three drivers of thermal phase variations are (1) obliquity seasons, (2) diurnal cycle, and (3) global seasons. Obliquity seasons are the dominant source of phase variations for most viewing angles. A pole-on observer

  19. Coupling diffusion and maximum entropy models to estimate thermal inertia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal inertia is a physical property of soil at the land surface related to water content. We have developed a method for estimating soil thermal inertia using two daily measurements of surface temperature, to capture the diurnal range, and diurnal time series of net radiation and specific humidi...

  20. Estimating Asteroid Thermal Inertia from Multi-epoch Observations

    NASA Astrophysics Data System (ADS)

    MacLennan, Eric M.; Emery, Joshua P.

    2014-11-01

    Granular material, or regolith, is observed to be ubiquitous on asteroid surfaces. To date, two feasible mechanisms of regolith generation have been proposed: recurrent impacts and thermal fracturing. By combining thermal infrared observations and a thermophysical model (TPM), the thermal inertia of an asteroid surface can be used to infer its physical properties, including the average regolith grain size. With the regolith properties of a large population of diverse asteroids (i.e. different spectral class, size, rotation period etc.), information regarding the details of regolith generation can be inferred.Traditional thermal inertia determination methods use a TPM with a previously derived asteroid shape model and spin axis for constraining the observed surface temperature distribution. TPMs invoke the heat diffusion equation to calculate surface temperatures for a rotating asteroid. An asteroid spin axis provide the boundary condition needed to calculate the surface energy balance in a TPM. However the limited amount of objects with a shape model and thermal infrared observations inhibit the number of thermal inertias that can potentially be calculated. Here, a technique using WISE (12 & 22 μm) observations taken before or after opposition is employed to derive thermal inertias of asteroids without using a shape model. By gathering thermal infrared data at multiple viewing geometries the temperature distribution, thus thermal inertia, is constrained.We first demonstrate the validity of this method on objects with a previously determined shape model and spin axis from the DAMIT website. Our analyses show that not knowing an asteroid’s shape does not significantly affect the resulting thermal inertia estimates. Additionally, we apply our TPM to WISE multi-epoch thermal observations to place estimates for the thermal inertia for more than 100 objects. The set of objects used samples many sizes, spectral classes and rotation periods, which may be important

  1. Thermal inertia characteristics of the Martian crater Curie

    NASA Technical Reports Server (NTRS)

    Horner, V. M.; Zimbelman, J. R.

    1987-01-01

    Thermal inertia characteristics have been determined for the martian crater Curie from high resolution groundtracks of Viking Thermal Infrared Mapper (IRTM) data. Flow features near the southeastern edge of the ejecta indicate that at least part of the Curie ejecta was emplaced in a manner similar to the ejecta of rampart craters. Within the study region there appears to be a general southeastern trend towards lower thermal inertia values. This trend may be related to the proximity of the Arabia region, which is mainly to the south and east of Curie. Curie is in a region where the overall thermal inertias change over relatively short distances radial to Arabia. Therefore, the observed general decrease in thermal inertia may represent increasing regional dust accumulation in the direction of Arabia.

  2. Rock Concentration and Thermal Inertia of Selected Lunar Study Regions.

    NASA Astrophysics Data System (ADS)

    Bauch, K. E.; Hiesinger, H.

    2012-04-01

    Temperature variations of lunar and planetary surfaces are directly influenced by their surface and subsurface thermophysical properties [1, 2]. These properties, namely bulk density, heat capacity, and thermal conductivity, are represented by thermal inertia, which is the ability of a surface and subsurface to conduct and store heat [2]. Materials with a low thermal inertia, such as dust and other fine-grained material, quickly respond to temperature changes, which results in a large temperature amplitude during the lunar cycle. Surfaces with high thermal inertia material, e.g. rocks or bedrock, take more time to heat up during the lunar day and reradiate the heat over extended periods. We derived maps of thermal inertia from LRO-Diviner nighttime temperature data [3]. The data was binned in one hour intervals with a minimum spatial resolution of 32 pixels/degree. For each surface facet we generated temperature-to-inertia look-up tables using a thermal model that solves the 1-D heat conduction equation. Model temperatures were then compared to measured data to find the best-fitting thermal inertia value. This approach is similar to martian thermal inertia derivations, as described by Mellon et al. (2000) and Putzig et al. (2005) [2, 4]. Due to the relatively large footprints of the used remote sensing data, anisothermal surfaces are observed within the field of view. Consequently, multiple thermal inertia units having variable temperatures are merged to a single observed temperature. However, the brightness temperature is a function of wavelength - it increases with decreasing wavelength. This nonlinearity of the Planck radiance can be used to determine rock concentrations [e.g., 5-7]. Therefore we used our model surface temperatures calculated with different thermal inertia and rock concentrations and compared these results to the LRO-Diviner temperature data at several wavelengths. The results were also compared to high-resolution Apollo and Lunar Reconnaissance

  3. Thermal Inertia Mapping Using Mars Climate Sounder Measurements.

    NASA Astrophysics Data System (ADS)

    Piqueux, S.; Kleinboehl, A.; Golombek, M. P.

    2014-12-01

    Previous work has shown inter-seasonal variations of the apparent thermal inertia at virtually all Martian latitudes. Because thermal inertia is mainly controlled by low variability parameters (e.g., grain sizes, degree of induration, rock abundance), these variations are usually interpreted in terms of subsurface layering and atmospheric contributions. Using atmospherically corrected surface temperatures at 32 μm wavelength (channel B1) from the Mars Climate Sounder (MCS) onboard Mars Reconnaissance Orbiter, we analyze the inter-seasonal variations of the apparent thermal inertia. We show that most of the previously observed inertia variations are eliminated, indicating that a simple homogeneous regolith structure is sufficient to explain most of the measurements. Also, as expected, a fraction of the observed variations remain, especially at high latitudes. This is consistent with subsurface layering involving water ice below dry regolith inferred from other measurement techniques and modeling. This work strengthens our ability to identify and characterize surface/subsurface material thermal inertias, layering and physical heterogeneities in the Martian surface layer, and will help eliminate seasonal striping on high-resolution inertia maps. In addition to a global scale analysis, we will discuss observations in western Elysium Planitia where the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander is planned to land in September 2016. We will provide predictions of the surface layer thermophysical properties, which are required for safe landing and successful scientific operations on the ground.

  4. Using Simple Shapes to Constrain Asteroid Thermal Inertia

    NASA Astrophysics Data System (ADS)

    MacLennan, Eric M.; Emery, Joshua P.

    2015-11-01

    With the use of remote thermal infrared observations and a thermophysical model (TPM), the thermal inertia of an asteroid surface can be determined. The thermal inertia, in turn, can be used to infer physical properties of the surface, specifically to estimate the average regolith grain size. Since asteroids are often non-spherical techniques for incorporating modeled (non-spherical) shapes into calculating thermal inertia have been established. However, using a sphere as input for TPM is beneficial in reducing running time and shape models are not generally available for all (or most) objects that are observed in the thermal-IR. This is particularly true, as the pace of infrared observations has recently dramatically increased, notably due to the WISE mission, while the time to acquire sufficient light curves for accurate shape inversion remains relatively long. Here, we investigate the accuracy of using both a spherical and ellipsoidal TPM, with infrared observations obtained at pre- and post-opposition (hereafter multi-epoch) geometries to constrain the thermal inertias of a large number of asteroids.We test whether using multi-epoch observations combined with a spherical and ellipsoidal shape TPM can constrain the thermal inertia of an object without a priori knowledge of its shape or spin state. The effectiveness of this technique is tested for 16 objects with shape models from DAMIT and WISE multi-epoch observations. For each object, the shape model is used as input for the TPM to generate synthetic fluxes for different values of thermal inertia. The input spherical and ellipsoidal shapes are then stepped through different spin vectors as the TPM is used to generate best-fit thermal inertia and diameter to the synthetically generated fluxes, allowing for a direct test of the approach’s effectiveness. We will discuss whether the precision of the thermal inertia constraints from the spherical TPM analysis of multi- epoch observations is comparable to works

  5. Temperature-dependent thermal inertia of homogeneous Martian regolith

    NASA Astrophysics Data System (ADS)

    Piqueux, Sylvain; Christensen, Philip R.

    2011-07-01

    Past studies of the thermophysical properties of the Martian surface layer have assumed temperature-independent thermal inertia, which is a function of the material density, specific heat, and bulk conductivity. In this paper, we evaluate the temperature-driven variations of these quantities for particulated and cemented material under Martian conditions of atmospheric pressure and temperature. Temperature-driven density variations are negligible. The specific heat of a basaltic material is strongly influenced by the temperature (˜75% increase from 150 to 315 K), inducing significant variations of the thermal inertia. The thermal conductivity of uncemented Martian regolith is weakly controlled by the solid phase conductivity and strongly controlled by the gaseous phase conductivity. As a result, the conductivity of the solid phase (i.e., composition, temperature) is unimportant, whereas medium to large variations (30-50%) of the bulk conductivity are associated with temperature-induced fluctuations of the pore-filling gas conductivity. Overall, the thermal inertia of uncemented Martian soils is predicted to vary significantly (˜80%) throughout the range of the observed surface temperatures. In the case of cemented soils, the contribution of the gas conductivity is generally small, and the solid phase (i.e., grains and cement) conductivity (i.e., composition, temperature) becomes more important. Consequently, the magnitude of the thermal inertia change for cemented soils is variable, and smaller than that predicted for uncemented materials (10-50%). Large diurnal and seasonal temperature variations only occur within the top material, and most of the near-surface regolith does not experience large thermal inertia variations. The shapes of modeled diurnal temperature curves are not significantly modified (e.g., the 0200 LT (Martian local time) apparent thermal inertia of uncemented regolith is up to ˜15% lower than the average daily inertia of the top material

  6. Geologic application of thermal inertia imaging using HCMM data

    NASA Technical Reports Server (NTRS)

    Paley, H. N.; Kahle, A. B. (Principal Investigator)

    1980-01-01

    The feasibility of using thermal inertia, inferred from remotely sensed temperature data, to complement LANDSAT reflectivity data for reconnaissance geologic mapping and mineral exploration is under investigation. The bulk of HCMM data tapes was received and processed, and a thermal inertia image of one data set was made. Additional areas of interest were identified on the HCMM photographic products and data tapes were ordered for these areas. During analysis of selected subareas, various sedimentary rock units were distinguished in the Death Valley, California test site and areas of altered rock were identified in the Cuprite/Goldifield, Nevada test site.

  7. Thermal inertia and bulk density of near-Earth asteroids

    NASA Astrophysics Data System (ADS)

    Rozitis, B.; Maclennan, E.; Emery, J.; Green, S.

    2014-07-01

    Thermal inertia and bulk density are two important properties that describe the surface morphology and internal structure of asteroids. Since thermal inertia depends predominantly on regolith particle size and depth, degree of compaction, and exposure of solid rocks and boulders within the top few centimeters of the sub-surface, it can be used to infer the presence or absence of loose material on the asteroid surface [1,2]. When the asteroid bulk density is compared with that of meteorites associated with the asteroid spectral type, then it allows the macro-porosity of the asteroid to be determined. The macro-porosity can then be used to infer whether the asteroid is predominantly a solid body throughout, a fractured body, or a rubble-pile [3]. Each structural classification gives different insights into how the asteroid formed and evolved. The thermal inertia and bulk density can be determined by simultaneous thermophysical modeling of thermal-infrared and Yarkovsky orbital drift observations. Thermal inertia is a measure of a material's resistance to temperature change and dictates the asteroid surface temperature distribution. Different thermal inertia values can be detected in thermal-infrared observations, and can be inferred by using a suitable thermophysical model that takes into account the asteroid's shape, rotation state, surface roughness, and observing geometry. The surface temperature distribution influenced by thermal inertia causes a morning-afternoon temperature asymmetry, which leads to an excess of thermally emitted photons on the afternoon side. This excess of photons applies a very small force to the afternoon side of the asteroid, which causes the orbital semimajor axis to increase or decrease slowly over time, depending on whether the asteroid is a prograde or retrograde rotator (i.e., the Yarkovsky effect [4]). The rate of Yarkovsky semimajor axis drift is dictated by the asteroid thermal inertia and bulk density, amongst other important

  8. Thermal and albedo mapping of the polar regions of Mars using Viking thermal mapper observations: 1. North polar region

    NASA Technical Reports Server (NTRS)

    Paige, David A.; Bachman, Jennifer E.; Keegan, Kenneth D.

    1994-01-01

    We present the first maps of the apparent thermal inertia and albedo of the north polar region of Mars. The observations used to create these maps were acquired by the infrared thermal mapper (IRTM) instruments on the two Viking orbiters over a 50-day period in 1978 during the Martian early northern summer season. The maps cover the region from 60 deg N to the north pole at a spatial resolution of 1/2 deg of latitude. The analysis and interpretation of these maps is aided by the results of a one-dimensional radiative convective model, which is used to calculate diurnal variations in surface and atmospheric temperatures, and brightness temperatures at the top of the atmospphere for a wide range of assumptions concerning aerosol optical properties and aerosol optical depths. The results of these calculations show that the effects of the Martian atmosphere on remote determinations of surface thermal inertia are more significant than have been indicated in previous studies. The maps of apparent thermal inertia and albedo show a great deal of spatial structure that is well correlated with surface features.

  9. Understanding seasonal variations in thermal inertia on Mars

    NASA Astrophysics Data System (ADS)

    Fergason, R. L.

    2013-12-01

    Thermal inertia is the key material property controlling the diurnal and seasonal temperature variations on Mars, and provides information about the physical characteristics and the cohesive nature of the surface and near subsurface. The derivation of accurate surface temperature and thermophysical properties, with well quantified uncertainties, has proven essential for selecting scientifically interesting and safe landing site locations and to understand past and present martian geologic processes thru the definitive identification of bedrock, and the recognition of indurated surfaces, unconsolidated fines, and dust. Most thermal inertia values reported for Mars are derived using a 1-layer thermal model, and often correlate reasonably well with surface textures and morphology observed in visible images. However, layered surfaces and mixtures materials of different grain sizes and degrees of cohesiveness are observed in visible images globally. Therefore, Mars is geologically complex and common 1-layer models are not a true representation of the surface and subsurface properties. In addition, thermal inertia values derived using 1-layer thermal models commonly produce variations in thermal inertia as large as 300 J m-2 s-1/2 K-1 that are often seasonally repeatable. These variations can lead to ambiguous interpretations of the surface and negatively impacts our ability to confidently interpret the surface properties of Mars. These differences also indicate that the current 1-layer models are often not adequately representing the physical properties of the martain surface. Although these seasonal variations are often interpreted as indicating the presence of subsurface layers, there are many potential causes of seasonal variations in thermal inertia that must be considered. Some of these potential causes include: 1) subsurface layering; 2) atmospheric variations; and 4) the omission of critical physics in the thermal models themselves. Subsurface layers of differing

  10. Global distribution of bedrock exposures on Mars using THEMIS high-resolution thermal inertia

    USGS Publications Warehouse

    Edwards, C.S.; Bandfield, J.L.; Christensen, P.R.; Fergason, R.L.

    2009-01-01

    We investigate high thermal inertia surfaces using the Mars Odyssey Thermal Emission Imaging System (THEMIS) nighttime temperature images (100 m/pixel spatial sampling). For this study, we interpret any pixel in a THEMIS image with a thermal inertia over 1200 J m-2 K-1 s-1/2 as "bedrock" which represents either in situ rock exposures or rock-dominated surfaces. Three distinct morphologies, ranked from most to least common, are associated with these high thermal inertia surfaces: (1) valley and crater walls associated with mass wasting and high surface slope angles; (2) floors of craters with diameters >25 km and containing melt or volcanics associated with larger, high-energy impacts; and (3) intercrater surfaces with compositions significantly more mafic than the surrounding regolith. In general, bedrock instances on Mars occur as small exposures (less than several square kilometers) situated in lower-albedo (<0.18), moderate to high thermal inertia (>350 J m-2 K-1 s-1/2), and relatively dust-free (dust cover index <0.95) regions; however, there are instances that do not follow these generalizations. Most instances are concentrated in the southern highlands, with very few located at high latitudes (poleward of 45oN and 58oS), suggesting enhanced mechanical breakdown probably associated with permafrost. Overall, Mars has very little exposed bedrock with only 960 instances identified from 75oS to 75oN with likely <3500 km2 exposed, representing???1% of the total surface area. These data indicate that Mars has likely undergone large-scale surface processing and reworking, both chemically and mechanically, either destroying or masking a majority of the bedrock exposures on the planet. Copyright 2009 by the American Geophysical Union.

  11. MGS-TES thermal inertia study of the Arsia Mons Caldera

    USGS Publications Warehouse

    Cushing, G.E.; Titus, T.N.

    2008-01-01

    Temperatures of the Arsia Mons caldera floor and two nearby control areas were obtained by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES). These observations revealed that the Arsia Mons caldera floor exhibits thermal behavior different from the surrounding Tharsis region when compared with thermal models. Our technique compares modeled and observed data to determine best fit values of thermal inertia, layer depth, and albedo. Best fit modeled values are accurate in the two control regions, but those in the Arsia Mons' caldera are consistently either up to 15 K warmer than afternoon observations, or have albedo values that are more than two standard deviations higher than the observed mean. Models of both homogeneous and layered (such as dust over bedrock) cases were compared, with layered-cases indicating a surface layer at least thick enough to insulate itself from diurnal effects of an underlying substrate material. Because best fit models of the caldera floor poorly match observations, it is likely that the caldera floor experiences some physical process not incorporated into our thermal model. Even on Mars, Arsia Mons is an extreme environment where CO2 condenses upon the caldera floor every night, diurnal temperatures range each day by a factor of nearly 2, and annual average atmospheric pressure is only around one millibar. Here, we explore several possibilities that may explain the poor modeled fits to caldera floor and conclude that temperature dependent thermal conductivity may cause thermal inertia to vary diurnally, and this effect may be exaggerated by presence of water-ice clouds, which occur frequently above Arsia Mons. Copyright 2008 by the American Geophysical Union.

  12. An instrument for measuring thermal inertia in the field

    NASA Technical Reports Server (NTRS)

    Marsh, S. E.; Schieldge, J. P.; Kahle, A. B.

    1982-01-01

    Features and test results of a thermal inertial meter (TIM) for cataloging the thermal inertial of surface material in situ as a basis for satellite remote sensing of geologic materials are described. The instrument is employed to determine the temperature rise of the materials in the field, with the assumptions that the sample and a standard are homogeneous in composition, the heat flux density is constant at the surface of each material, and the specimens are thick enough to be treated as semi-infinite bodies. A formula for calculating thermal inertia is presented, and the components of the TIM are detailed. A box with three compartments, two holding standards, is placed on the sample surface with the third compartment open to the specimen. Dolomite and quartz are used as references when all samples are measured after heating. Tests with rocks and sand in Nevada and California revealed that chert has a higher thermal inertia than barite.

  13. Thermal Properties, Size Distribution, and Albedo Distribution of Jupiter-Family Comets

    NASA Astrophysics Data System (ADS)

    Fernandez, Yanga R.; Kelley, M. S.; Lamy, P. L.; Toth, I.; Groussin, O.; Lisse, C. M.; A'Hearn, M. F.; Bauer, J. M.; Campins, H.; Fitzsimmons, A.; Licandro, J.; Lowry, S. C.; Meech, K. J.; Pittichova, J.; Reach, W. T.; Weaver, H. A.

    2007-10-01

    We present results from SEPPCoN (Survey of Ensemble Physical Properties of Cometary Nuclei), a survey of 100 Jupiter-family comets (JFCs) using the Spitzer Space Telescope for mid-infrared measurements of thermal emission and several ground-based telescopes for visible-wavelength measurements of reflected sunlight. Our sample represents about 30% of all known JFCs. The Spitzer observations are complete, and each comet was observed at either two wavelengths (16 and 22 μm) or at one wavelength twice (24 μm). Our survey constrains the effective radii of the JFC nuclei and thence the size distribution while only assuming that cometary geometric albedos are low (few percent); we need not assume that they are all the same. Also, nearly all survey targets were observed when farther than 4 AU from the Sun to minimize (and in most cases eliminate) coma confusion. Using the observations of comets at two wavelengths, and using the Near-Earth Asteroid Thermal Model, we have estimated the JFC ensemble-average beaming parameter to be about 1.1. On average, cometary nuclei seem to have low thermal inertia and not have significant infrared beaming, although we do find that some of our survey targets have significantly higher parameters and thus likely higher thermal inertia. Analysis on the cumulative size distribution continues and we present our preliminary estimate of its shape, as well as the implications for the assumption of uniform albedo and for the extent of the small-comet (sub-km) population. So far we have obtained visible magnitudes on almost half of our targets; we plan to complete this part of the survey in the coming years. With these data we will constrain the JFC albedo distribution and again address the question of albedo uniformity; current progress on this task is reported as well. We thank the Spitzer Science Center for supporting this research.

  14. The effect of biochar application on thermal inertia of soil

    NASA Astrophysics Data System (ADS)

    Usowicz, Boguslaw; Lipiec, Jerzy; Lukowski, Mateusz; Marczewski, Wojciech; Usowicz, Jerzy

    2015-04-01

    In recent times main causes of soil degradation include intensive farming, the shortage of water in the soil or droughts associated with climate and increasing amount of CO2 in the atmosphere. Reducing the negative effects and rational management of biomass and wastes require effective and economical solutions. One of them can be application of biochar to retain more water, improve the quality and fertility of the soil and modify thermal properties of soil. In his study the effect of biochar, obtained from the wood biomass, on soil thermal inertia was assessed. The thermal inertia of the soil is defined as Cv*sqrt(D), where Cv is the heat capacity and D is the thermal diffusivity. The experimental plots were: grass covered soil and fallow with addition of 0, 10, 20 and 30 Mg/ha of biochar in each and pure biochar was used for comparison. Addition of biochar resulted in a decrease of the soil heat capacity in dry state and considerable increase in wet state. The results revealed that addition of the biochar into the soil caused considerable reduction of the thermal diffusivity. The reduction of both properties in dry state was mostly due to decrease in both particle density and bulk density of the soil. The observed lowest and highest reduction in the thermal inertia with decreasing water content was obtained for pure biochar and the biochar amended soil, respectively.

  15. Geologic application of thermal-inertia mapping from satellite. [Arizona and Powder River, Wyoming

    NASA Technical Reports Server (NTRS)

    Offield, T. W. (Principal Investigator); Miller, S. H.; Watson, K.

    1978-01-01

    The author has identified the following significant results. A theoretical evaluation of the proportional and linear relationship between absolute and relative thermal inertia was performed, and a potentially more accurate expression for absolute thermal inertia mapping was proposed.

  16. Classification of surface units in the equatorial region of Mars based on Viking Orbiter color, albedo, and thermal data

    NASA Technical Reports Server (NTRS)

    Arvidson, R. E.; Guinness, E. A.; Zent, A. P.

    1982-01-01

    Clusters corresponding to mappable surface units are sought in Viking Orbiter color, albedo, and thermal inertia data for the equatorial region of Mars. A principal components analysis indicated that 84% of the variance within the data for this region can be carried along two vector directions which typify the dominant trend of Martian surface materials. These dominant trends were deemphasized by stretching the data from a five-dimensional elliptical swarm into a hypersphere, through the use of principal component techniques. The decorrelated data were then plotted in a triangle diagram with red/violet, albedo and thermal inertia apices to facilitate inherent cluster discrimination. As many as eight clusters can be identified, with important mixing between them. The three major clusters consist of red and grey material extremes, along with intermediate value materials.

  17. The diameter and thermal inertia of 433 Eros

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1976-01-01

    Radiometry of Eros at 10 and 20 micrometers demonstrates that the thermal conductivity of the upper centimeter of the surface is approximately as low as that of the moon, suggesting that the asteroid has a regolith of highly porous rocky material. When combined with photoelectric photometry, these infrared measurements yield an effective diameter of Eros at maximum light of 22 plus or minus 2 km and a geometric albedo of 0.18 plus or minus 0.03.

  18. Calculation of thermal inertia from day-night measurements separated by days or weeks

    NASA Technical Reports Server (NTRS)

    Kahle, A. B.; Alley, R. E.

    1985-01-01

    The calculation of the thermal inertia of an area from remotely sensed data involves the measurement of the surface albedo and the determination of the diurnal temperature range of the surface in image format. The temperature-range image is calculated from surface thermal radiance measured as near as possible to the time of maximum surface temperature and (predawn) surface minimum temperature. Ordinarily, both surface-temperature images are measured within the same 12-hour period. If this is impossible, then the measurement of the predawn surface radiance within a 36-hour period has been considered to be adequate, although less satisfactory. The problems arising in connection with the impossibility to conduct measurements within the same 12-hour period are studied, and suggestions are made for cases in which only relative thermal inertia across an area is required. In such cases investigators should consider using the best day-night temperature pairs available, even if not acquired within a 12 to 36 hour period.

  19. Sensitivity of thermal inertia calculations to variations in environmental factors. [in mapping of Earth's surface by remote sensing

    NASA Technical Reports Server (NTRS)

    Kahle, A. B.; Alley, R. E.; Schieldge, J. P.

    1984-01-01

    The sensitivity of thermal inertia (TI) calculations to errors in the measurement or parameterization of a number of environmental factors is considered here. The factors include effects of radiative transfer in the atmosphere, surface albedo and emissivity, variations in surface turbulent heat flux density, cloud cover, vegetative cover, and topography. The error analysis is based upon data from the Heat Capacity Mapping Mission (HCMM) satellite for July 1978 at three separate test sites in the deserts of the western United States. Results show that typical errors in atmospheric radiative transfer, cloud cover, and vegetative cover can individually cause root-mean-square (RMS) errors of about 10 percent (with atmospheric effects sometimes as large as 30-40 percent) in HCMM-derived thermal inertia images of 20,000-200,000 pixels.

  20. The longitudinal variation of the thermal inertia and of the 2.8 centimeter brightness temperature of Mars

    NASA Technical Reports Server (NTRS)

    Jakosky, B. M.; Muhleman, D. O.

    1980-01-01

    The spatial variations on Mars of the surface thermal inertia and radiometric albedo are used to predict the variation with sub-earth longitude of the 2.8 cm whole-disk brightness temperature. The maximum variation predicted, about 8 K, agrees well with observations. The sub-earth longitudes at which the temperature maxima and minima are predicted to occur nearly agree with the observations. There are, however, differences in the overall form of the variation with longitude. These discrepancies can be reduced by an ad hoc assumption of spatial variations in either the fraction of the surface covered by rock or the amount of atmospheric dust.

  1. The radiobrightness thermal inertia measure of soil moisture

    NASA Technical Reports Server (NTRS)

    England, Anthony W.; Galantowicz, John F.; Schretter, Mindy S.

    1992-01-01

    Radiobrightness thermal inertia (RTI) is proposed as a method for using day-night differences in satellite-sensed radiobrightness to monitor the moisture of Great Plains soils. Diurnal thermal and radiobrightness models are used to examine the sensitivity of the RTI method. Model predictions favor use of the 37.0 and 85.5 GHz, H-polarized channels of the Special Sensor Microwave/Imager (SSM/I). The model further predicts that overflight times near 2:00 AM/PM would be nearly optimal for RTI, that midnight/noon and 4:00 AM/PM are nearly as good, but that the 6:00 AM/PM overflight times of the current SSM/I are particularly poor. Data from the 37.0 GHz channel of the Scanning Multichannel Microwave Radiometer (SMMR) are used to demonstrate that the method is plausible.

  2. Surface soil water content estimation based on thermal inertia and Bayesian smoothing

    NASA Astrophysics Data System (ADS)

    Addesso, Paolo; Maltese, Antonino; Garella, Riccardo; Capodici, Fulvio; D'Urso, Guido; Longo, Maurizio; Restaino, Rocco; Vivone, Gemine

    2014-10-01

    Soil water content plays a critical role in agro-hydrology since it regulates the rainfall partition between surface runoff and infiltration and, the energy partition between sensible and latent heat fluxes. Current thermal inertia models characterize the spatial and temporal variability of water content by assuming a sinusoidal behavior of the land surface temperature between subsequent acquisitions. Such behavior implicitly supposes clear sky during the whole interval between the thermal acquisitions; but, since this assumption is not necessarily verified even if sky is clear at the exact epoch of acquisition, , the accuracy of the model may be questioned due to spatial and temporal variability of cloud coverage. During the irrigation season, cloud coverage exhibits a quite regular daily behavior, which, when rendered in probabilistic terms, allows for an a-priory evaluation of the most likely suitable pair of images to estimate thermal inertia, given the results of the satellite passes. In turn, the water content of soil is estimated through thermal inertia by coupling diurnal optical and nighttime thermal images, e.g. as acquired by MODIS sensor on board polar orbiting satellites AQUA and TERRA, which have spatial resolution high enough to cope with typical agricultural applications. The method relies on the availability of the shortwave albedo and, at least, two daily thermographs preferably acquired in specific epochs of the day: the first at sunset when latent and heat fluxes are negligible; the second just before sunrise, when surface soil temperature reaches its minimum. Unfortunately, high resolution thermal images are often not available in those specific epochs, so that the accuracy of estimate accuracy decays even severely. In this perspective the paper, following previous contributions by some of the authors of the present paper [1-4], proposes exploiting SEVIRI data, characterized by higher acquisition rate but coarser spatial resolution as available

  3. Martian particle size based on thermal inertia corrected for elevation-dependent atmospheric properties

    NASA Technical Reports Server (NTRS)

    Bridges, N. T.

    1993-01-01

    Thermal inertia is commonly used to derive physical properties of the Martian surface. If the surface is composed of loosely consolidated grains, then the thermal conductivity derived from the inertia can theoretically be used to compute the particle size. However, one persistent difficulty associated with the interpretation of thermal inertia and the derivation of particle size from it has been the degree to which atmospheric properties affect both the radiation balance at the surface and the gas conductivity. These factors vary with atmospheric pressure so that derived thermal inertias and particle sizes are a function of elevation. By utilizing currently available thermal models and laboratory information, a fine component thermal inertia map was convolved with digital topography to produce particle size maps of the Martian surface corrected for these elevation-dependent effects. Such an approach is especially applicable for the highest elevations on Mars, where atmospheric back radiation and gas conductivity are low.

  4. Geologic application of thermal-inertia mapping from satellite. [Powder River Basin in Wyoming and Montana

    NASA Technical Reports Server (NTRS)

    Offield, T. W. (Principal Investigator); Miller, S. H.; Watson, K.

    1978-01-01

    The author has identified the following significant results. The proportional and linear relationship between absolute and relative thermal inertia was theoretically evaluated, and a more accurate expression for thermal inertia was proposed. Radiometric and meteorological data from three stations in the Powder River Basin were acquired, as well as 400 miles of low altitude scanner data between July 25-28.

  5. Low thermal inertias of icy planetary surfaces. Evidence for amorphous ice?

    NASA Astrophysics Data System (ADS)

    Ferrari, C.; Lucas, A.

    2016-04-01

    Context. Thermal inertias of atmosphereless icy planetary bodies happen to be very low. Aims: We relate the thermal inertia to the regolith properties such as porosity, grain size, ice form and heat transfer processes to understand why it is low. We interpret the dichotomy in thermal inertia of the surface of Mimas in terms of changes in regolith properties. We predict how the thermal inertia of these bodies may vary with heliocentric distance depending on these properties. Methods: We combine available models of conductivity by contact or radiation to understand what heat transfer process is predominant. Results: The magnitude of the thermal inertia of a porous icy regolith is mainly governed by the crystalline or amorphous ice forms, and the quality of contacts between grains. Beyond the orbit of Jupiter, thermal inertias as low as a few tens J/m2/ K/s1/2 are difficult to reproduce with plausible porosity and grains sizes made of crystalline ice unless contacts are loose. This is, on the contrary, straightforward for regoliths of sub-cm-sized grains made of amorphous water ice. This study points out the importance of including the temperature dependence of thermophysical properties of water ice forms and the radiative conduction in thermal models of these bodies. The relatively high thermal inertia of the leading face of Mimas can be explained by a regolith of crystalline ice grains in tight contacts, which are eventually sintered by the bombardment of high energy electrons. The low thermal inertia of its trailing face is easily reproduced by a regolith of moderate porosity with sub-mm-sized grains of amorphous ice. The characteristic decrease of thermal inertia with heliocentric distance of icy atmosphereless surfaces and the very low thermal inertia of relevant trans-Neptunian objects are easily explained if amorphous ice is present at cm depths below a thin layer of crystalline ice.

  6. Physical characterization of the potentially hazardous high-albedo Asteroid (33342) 1998 WT 24 from thermal-infrared observations

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Mueller, Michael; Delbó, Marco; Bus, Schelte J.

    2007-06-01

    The potentially hazardous Asteroid (33342) 1998 WT 24 approached the Earth within 0.0125 AU on 2001 December 16 and was the target of a number of optical, infrared, and radar observing campaigns. Interest in 1998 WT 24 stems from its having an orbit with an unusually low perihelion distance, which causes it to cross the orbits of the Earth, Venus, and Mercury, and its possibly being a member of the E spectral class, which is rare amongst near-Earth asteroids (NEAs). We present the results of extensive thermal-infrared observations of 1998 WT 24 obtained in December 2001 with the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii and the ESO 3.6-m telescope in Chile. A number of thermal models have been applied to the data, including thermophysical models that give best-fit values of 0.35±0.04 km for the effective diameter, 0.56±0.2 for the geometric albedo, p, and 100-300 J m -2 s -0.5 K -1 for the thermal inertia. Our values for the diameter and albedo are consistent with results derived from radar and polarimetric observations. The albedo is one of the highest values obtained for any asteroid and, since no other taxonomic type is associated with albedos above 0.5, supports the suggested rare E-type classification for 1998 WT 24. The thermal inertia is an order of magnitude higher than values derived for large main-belt asteroids but consistent with the relatively high values found for other near-Earth asteroids. A crude pole solution inferred from a combination of our observations and published radar results is β=-52°, λ=355° (J2000), but we caution that this is uncertain by several tens of degrees.

  7. Thermal inertia mapping and its application in mineral exploration: results from Mamandur polymetal prospect, India

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, D.; Bharti, Rishikesh; Singh, K. D.; Nithya, M.

    2013-10-01

    Thermal anomalies associated with ore-mineralization (Pb-Cu-Zn and Fe) were studied using thermal infrared data collected over Mamandur polymetal prospect, India, with the aid of satellite, field, and laboratory measurements. Day and night ASTER data were analysed in conjunction with field measurements to estimate thermal inertia of the ore body, altered zones and country rocks. Representative samples collected from field were also analysed for thermal conductivity, diffusivity, and inertia using a self-fabricated setup. Spatial changes in thermal inertia were mapped by look up table (LUT) and advanced thermal inertia mapping (ATIM) approaches. Mineralized zones show very high thermal contrast (ΔT) both in field (15-25°C) and satellite data (14.9-16.9oC). They also exhibit the lowest thermal inertia in field-(2118-5474 J m-2 K-1 s-1/2) and satellite-based (3783-4037 J m-2 K-1 s-1/2) measurements. In non-mineralized areas, acidic rocks (granite, migmatite and granite gneiss) have lower inertia than basic rocks (basic granulite, dolerite and charnockite). Results estimated by LUT and ATIM approaches correlate very well at satellite (R2 = 0.97) and field (R2 = 0.89) scales. Similarly, field- and satellite-based results also have good correlation (R2 = 0.69-0.72). This study illustrates the potential of thermal inertia mapping in delineating ore bodies and deciphering the lithological changes even under veneer of soil.

  8. An application of thermal inertia in regional evapotranspiration retrieval

    NASA Astrophysics Data System (ADS)

    Mi, S.

    2015-12-01

    Accurate estimates of the spatial distribution of evapotranspiration (ET) are of crucial importance in disciplines of hydrology, meteorology and agriculture, especially in arid and semi-arid areas where water scarcity is becoming a major constraint on economic welfare and sustainable development. Space feature models are widely used in estimating ET nowadays. The locations of dry line and wet line are important to the retrieving results, especially for the dry lines, which are more difficult to determine than wet lines since dry lines do not exist in wet period. In this paper, simplified thermal inertia values of sandy soil samples and full vegetation covered samples measured in laboratory are used in the middle reaches of Heihe River to determine the locations of dry line in wet periods and dry periods. Six Aster images form 1st June to 12th September of Year 2012 are used in the study. The results shows that the ET results from our approach shows a high agreement (R > 0.85) with the observed ET in Heihe and the method can be used in Heihe area to estimate regional ET.

  9. The complex relationship between olivine abundance and thermal inertia on Mars

    NASA Astrophysics Data System (ADS)

    Hanna, Romy D.; Hamilton, Victoria E.; Putzig, Nathaniel E.

    2016-07-01

    We examine four olivine-bearing regions at a variety of spatial scales with thermal infrared, visible to near-infrared, and visible imagery data to investigate the hypothesis that the relationship between olivine abundance and thermal inertia (i.e., effective particle size) can be used to infer the occurrence of olivine chemical alteration during sediment production on Mars. As in previous work, Nili Fossae and Isidis Planitia show a positive correlation between thermal inertia and olivine abundance in Thermal Emission Spectrometer (TES) and Thermal Emission Imaging System (THEMIS) data, which could be interpreted as indicating olivine chemical weathering. However, geomorphological analysis reveals that relatively olivine-poor sediments are not derived from adjacent olivine-rich materials, and therefore, chemical weathering cannot be inferred based on the olivine-thermal inertia relationship alone. We identify two areas (Terra Cimmeria and Argyre Planitia) with significant olivine abundance and thermal inertias consistent with sand, but no adjacent rocky (parent) units having even greater olivine abundances. More broadly, global analysis with TES reveals that the most typical olivine abundance on Mars is ~5-7% and that olivine-bearing (5-25%) materials have a wide range of thermal inertias, commonly 25-600 J m-2 K-1 s-1/2. TES also indicates that the majority of olivine-rich (>25%) materials have apparent thermal inertias less than 400 J m-2 K-1 s-1/2. In summary, we find that the relationship between thermal inertia and olivine abundance alone cannot be used in infer olivine weathering in the examined areas, that olivine-bearing materials have a large range of thermal intertias, and therefore that a complex relationship between olivine abundance and thermal inertia exists on Mars.

  10. Thermal inertia mapping of Mars from 60°S to 60°N

    USGS Publications Warehouse

    Palluconi, Frank Don; Kieffer, Hugh H.

    1981-01-01

    Twenty-micrometer brightness temperatures are used to derive the thermal inertia for 81% of the Martian surface between latitudes ±60°. These data were acquired by the two Viking Infrared Thermal Mappers in 1977 and 1978 following the two global dust storms of 1977. The spatial resolution used is 2° in latitude by 2° in longitude and the total range in derived inertia is . The distribution of thermal inertia is strongly bimodal with all values of thermal inertia less than  being associated with three disjoint bright regions mostly in the northern hemisphere. Sufficient dust is raised in global storms to provide fine material adequate to produce these low-inertia areas but the specific deposition mechanism has not been defined. At the low resolution used, no complete exposures of clean rock were found. There is some tendency for darker material to be associated with higher thermal inertia, although the trend is far from one to one. The distribution of high- and low-inertia areas is sufficiently nonrandom to produce a variation in whole-disk brightness temperature with central meridian longitude. This variation and the change in surface kinetic temperature associated with dust storms are factors in establishing the whole-disk brightness temperature at radio and infrared wavelengths and will be important for those who use Mars as a calibration source.

  11. The Negligible Role of Thermal Inertia in the Marangoni Instability and Evaporation Instability Problems

    NASA Astrophysics Data System (ADS)

    Shrefler, John; Dietze, Georg; Narayanan, Ranga

    2015-11-01

    The classical Marangoni instability problem, principally introduced by Pearson in 1958, takes the interface of two fluids heated from below to be non-deflecting and as a consequence of this assumption thermal inertia is responsible for the onset of convective flows. However, in practical problems where interfacial deflections are uncontrollable and necessarily present, we find that thermal inertia is of very little importance for a broad class of fluids. Neglecting the contribution of thermal inertia, we find that the instability persists as in the classical case. This is shown by way of an integral boundary layer method for long wavelength flows and confirmed by detailed calculations using the full equations. We aim to demonstrate that the principal result that thermal inertia is unimportant continues to hold for the evaporation instability problem, provided pure component phase change is considered. Supported by NSF 0968313 and Marie Curie IRSES grants.

  12. Surface energy budget and thermal inertia at Gale Crater: Calculations from ground-based measurements

    PubMed Central

    Martínez, G M; Rennó, N; Fischer, E; Borlina, C S; Hallet, B; de la Torre Juárez, M; Vasavada, A R; Ramos, M; Hamilton, V; Gomez-Elvira, J; Haberle, R M

    2014-01-01

    The analysis of the surface energy budget (SEB) yields insights into soil-atmosphere interactions and local climates, while the analysis of the thermal inertia (I) of shallow subsurfaces provides context for evaluating geological features. Mars orbital data have been used to determine thermal inertias at horizontal scales of ∼104 m2 to ∼107 m2. Here we use measurements of ground temperature and atmospheric variables by Curiosity to calculate thermal inertias at Gale Crater at horizontal scales of ∼102 m2. We analyze three sols representing distinct environmental conditions and soil properties, sol 82 at Rocknest (RCK), sol 112 at Point Lake (PL), and sol 139 at Yellowknife Bay (YKB). Our results indicate that the largest thermal inertia I = 452 J m−2 K−1 s−1/2 (SI units used throughout this article) is found at YKB followed by PL with I = 306 and RCK with I = 295. These values are consistent with the expected thermal inertias for the types of terrain imaged by Mastcam and with previous satellite estimations at Gale Crater. We also calculate the SEB using data from measurements by Curiosity's Rover Environmental Monitoring Station and dust opacity values derived from measurements by Mastcam. The knowledge of the SEB and thermal inertia has the potential to enhance our understanding of the climate, the geology, and the habitability of Mars. PMID:26213666

  13. Surface energy budget and thermal inertia at Gale Crater: Calculations from ground-based measurements

    NASA Astrophysics Data System (ADS)

    Martínez, G. M.; Rennó, N.; Fischer, E.; Borlina, C. S.; Hallet, B.; Torre Juárez, M.; Vasavada, A. R.; Ramos, M.; Hamilton, V.; Gomez-Elvira, J.; Haberle, R. M.

    2014-08-01

    The analysis of the surface energy budget (SEB) yields insights into soil-atmosphere interactions and local climates, while the analysis of the thermal inertia (I) of shallow subsurfaces provides context for evaluating geological features. Mars orbital data have been used to determine thermal inertias at horizontal scales of ~104 m2 to ~107 m2. Here we use measurements of ground temperature and atmospheric variables by Curiosity to calculate thermal inertias at Gale Crater at horizontal scales of ~102 m2. We analyze three sols representing distinct environmental conditions and soil properties, sol 82 at Rocknest (RCK), sol 112 at Point Lake (PL), and sol 139 at Yellowknife Bay (YKB). Our results indicate that the largest thermal inertia I = 452 J m-2 K-1 s-1/2 (SI units used throughout this article) is found at YKB followed by PL with I = 306 and RCK with I = 295. These values are consistent with the expected thermal inertias for the types of terrain imaged by Mastcam and with previous satellite estimations at Gale Crater. We also calculate the SEB using data from measurements by Curiosity's Rover Environmental Monitoring Station and dust opacity values derived from measurements by Mastcam. The knowledge of the SEB and thermal inertia has the potential to enhance our understanding of the climate, the geology, and the habitability of Mars.

  14. The role of porosity in thermal inertia variations on basaltic lavas

    NASA Technical Reports Server (NTRS)

    Zimbelman, James R.

    1986-01-01

    Thermal inertia, defined as the square root of the product of thermal conductivity, density, and specific heat, has been noted to vary in inverse proportion to porosity in Hawaiian basalts. It is presently suggested that porosities of the order of more than 80 percent are required if the low thermal inertias observed in Martian shield volcanoes are the result of pristine lava flow surface properties. An aeolian origin is held to be most likely in view of thermal measurements on Mars; the volcanic surfaces in question are anticipated to have a short lifetime in their environment.

  15. Atmospheric effects on the remote determination of thermal inertia on Mars

    NASA Astrophysics Data System (ADS)

    Haberle, R. M.; Jakosky, B. M.

    1991-04-01

    Measurements of the IR brightness temperature at the Martian surface at many different times of day are presently compared with temperatures predicted by thermal models which allow sunlight to reach the surface unattenuated, in order to determine the thermal inertia of the uppermost 1-10 cm of the Martian surface. The consequences of the assumptions made are assessed in view of results from a different thermal model which invokes radiation-transfer through a dusty CO2 atmosphere, as well as sensible heat-exchange with the surface. Smaller thermal inertias imply smaller particle sizes; the results obtained suggest that low thermal-inertia regions consist of 5-micron, rather than 50-micron, particle sizes.

  16. Atmospheric effects on the remote determination of thermal inertia on Mars

    NASA Technical Reports Server (NTRS)

    Haberle, Robert M.; Jakosky, Bruce M.

    1991-01-01

    Measurements of the IR brightness temperature at the Martian surface at many different times of day are presently compared with temperatures predicted by thermal models which allow sunlight to reach the surface unattenuated, in order to determine the thermal inertia of the uppermost 1-10 cm of the Martian surface. The consequences of the assumptions made are assessed in view of results from a different thermal model which invokes radiation-transfer through a dusty CO2 atmosphere, as well as sensible heat-exchange with the surface. Smaller thermal inertias imply smaller particle sizes; the results obtained suggest that low thermal-inertia regions consist of 5-micron, rather than 50-micron, particle sizes.

  17. Thermal inertias in the upper millimeters of the Martian surace derived using Phobus' shadow

    NASA Technical Reports Server (NTRS)

    Betts, Bruce H.; Murray, Bruce C.; Svitek, Tomas

    1995-01-01

    The first thermal images of Phobos' shadow on the surface of Mars, in addition to simultaneous visible images, were obtained by the Phobus '88 Termoskan instrument. The best observed shadow occurence was on the flanks of Arsia Mons. For this occurence, we combined the observed decrease in visible illumination of the surface with the observed decrease in brightness temperature to calculate thermal inertias of the Martian surface. The most realistic of our three models of eclipse cooling improves upon our preliminary model by including nonisothermal initial conditions and downward atmospheric flux. Most of our derived inertias fall within the range 38 to 59 J/Sq m/S(exp 0.5)K (0.9 to 1.4 10(exp -3)Cal/Sq m/S(exp 0.5)/K), corresponding to dust-sized particles (for a homogeneous surface), consistent with previous theories of Tharsis as a currrent area of dust deposition. Viking infrared thermal mapper (IRTM) inertias are diurnally derived and are sensitive to centimeter depths, whereas the shadow-derived inertias sample the upper tenths of a millimeter of the surface. The shadow-derived inertias are lower than those derived from Viking IRTM measurements (84 to 147), however, uncertainties in both sets of derived inertias make conclusions about layering tenuous. Thus, near-surface millimeter versus centimeter layering may exist in this region, but if it does, it is likely not very significant. Both eclipse and diurnal inertias appear to increase near the eastern end of the shadow occurence. We also analyzed a shadow occurence near the crater Herschel that showed no observed cooling. This analysis was limited by cool morning temperatures and instrument sensitivity, but yielded a lower bound of 80 on eclipse inertias in that region. Based upon our results, we strongly recommend future spacecraft thermal observations of Phobus' shadow, and suggest that they will be most useful if they improve upon Termoskan's geographic and temporal coverage and its accuracy.

  18. Thermal inertias in the upper millimeters of the Martian surface derived using Phobos' shadow

    NASA Technical Reports Server (NTRS)

    Betts, Bruce H.; Murray, Bruce C.; Svitek, Tomas

    1995-01-01

    The first thermal images of Phobos' shadow on the surface of Mars, in addition to simultaneous visible images, were obtained by the Phobos'88 Termoskan instrument. The best observed shadow occurrence was on the flanks of Arsia Mons. For this occurrence, we combined the observed decrease in visible illumination of the surface with the observed decrease in brightness temperature to calculate thermal inertias of the Martian surface. The most realistic of our three models of eclipse cooling improves upon our preliminary model by including nonisothermal initial conditions and downward atmospheric flux. Most of our derived inertias fall within the range 38 to 59 J/(sq m s(exp 1/2) K), (0.9 to 1.4 x 10(exp -3) cal/(sq cm s(exp 1/2) K)) corresponding to dust-sized particles (for a homogeneous surface), consistent with previous theories of Tharsis as a current area of dust deposition. Viking infrared thermal mapper (IRTM) inertias are diurnally derived and are sensitive to centimeter depths, whereas the shadow-derived inertias sample the upper tenths of a millimeter of the surface. The shadow-derived inertias are lower than those derived from Viking IRTM measurements (84 to 147), however, uncertainties in both sets of derived inertias make conclusions about layering tenuous. Thus, near-surface millimeter versus centimeter layering may exist in this region, but if it does, it is likely not very significant. Both eclipse and diurnal inertias appear to increase near the eastern end of the shadow occurrence. We also analyzed a shadow occurrence near the crater Herschel that showed no observed cooling. This analysis was limited by cool morning temperatures and instrument sensitivity, but yielded a lower bound of 80 on eclipse inertias in that region. Based upon our results, we strongly recommend future spacecraft thermal observations of Phobos' shadow, and suggest that they will be most useful if they improve upon Terinoskan's geographic and temporal coverage and its accuracy.

  19. THERMAL-INERTIA MAPPING IN VEGETATED TERRAIN FROM HEAT CAPACITY MAPPING MISSION SATELLITE DATA.

    USGS Publications Warehouse

    Watson, Ken; Hummer-Miller, Susanne

    1984-01-01

    Thermal-inertia data, derived from the Heat Capacity Mapping Mission (HCMM) satellite, were analyzed in areas of varying amounts of vegetation cover. Thermal differences which appear to correlate with lithologic differences have been observed previously in areas of substantial vegetation cover. However, the energy exchange occurring within the canopy is much more complex than that used to develop the methods employed to produce thermal-inertia images. Because adequate models are lacking at present, the interpretation is largely dependent on comparison, correlation, and inference. Two study areas were selected in the western United States: the Richfield, Utah and the Silver City, Arizona-New Mexico, 1 degree multiplied by 2 degree quadrangles. Many thermal-inertia highs were found to be associated with geologic-unit boundaries, faults, and ridges. Lows occur in valleys with residual soil cover.

  20. Ground-Atmosphere Interactions at Gale: Determination of the Surface Energy Budget, Thermal Inertia and Water Sorption on the Regolith

    NASA Astrophysics Data System (ADS)

    Martinez, German; Renno, Nilton; Fischer, Erik; Borlina, Caue; Hallet, Bernard; De la Torre Juarez, Manuel; Vasavada, Aswhin; Gomez-Elvira, Javier

    2014-05-01

    The analysis of the Surface Energy Budget (SEB) yields insights into the local climate and the soil-atmosphere interactions, while the analysis of the thermal inertia of the shallow subsurface augments surface observations, providing information about the local geology. The Mars Global Surveyor Thermal Emission Spectrometer and the Mars Odyssey Thermal Emission Imaging System have measured near subsurface thermal inertia from orbit at scales of ~104 m2 to ~10 km2. Here we report analysis of the thermal inertia at a few locations at Gale Crater at scales of 100 m2. The thermal inertia is calculated by solving the heat conduction equation in the soil using hourly measurements by the Rover Environmental Station (REMS) ground temperature sensor as an upper boundary condition. Three Sols representative of different environmental conditions and soil properties, namely, Sol 82 at Rocknest (RCK), Sol 112 at Point Lake (PL) and Sol 139 at Yellowknife Bay (YKB) are analyzed in detail. The largest thermal inertia (I) value is found at YKB, I = 445 J m-2 K-1 s-1/2 or 445 tiu (thermal inertia unit), followed by PL with I= 300 tiu and RCK withI = 280 tiu [1]. These values are consistent with the type of terrain imaged by MastCam and with previous satellite estimates at Gale Crater [2,3]. The SEB is calculated by using all REMS data products as well as dust opacity values derived from MastCam measurements, whereas previously, the SEB has been calculated using numerical models only [4]. At each location and during the daytime, the SEB is dominated by the downwelling shortwave (SW) solar radiation (~450-500 W/m2) and the upwelling longwave (LW) radiation emitted by the surface (~300-400 W/m2). The sum of these two terms accounts for at least 70% of the net surface heating rate between 0900 and 1400 local solar time. At nighttime, the SEB is dominated by the upwelling LW radiation emitted by the surface (~50-100 W/m2) and the downwelling LW radiation from the atmosphere (~50 W/m2

  1. A Global Map of Thermal Inertia from Mars Global Surveyor Mapping-Mission Data

    NASA Technical Reports Server (NTRS)

    Mellon, M. T.; Kretke, K. A.; Smith, M. D.; Pelkey, S. M.

    2002-01-01

    TES (thermal emission spectrometry) has obtained high spatial resolution surface temperature observations from which thermal inertia has been derived. Seasonal coverage of these data now provides a nearly global view of Mars, including the polar regions, at high resolution. Additional information is contained in the original extended abstract.

  2. Thermal Inertia of Rocks and Rock Populations and Implications for Landing Hazards on Mars

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Jakosky, B. M.; Mellon, M. T.

    2001-01-01

    Rocks represent an obvious potential hazard to a landing spacecraft. They also represent an impediment to rover travel and objects of prime scientific interest. Although Mars Orbiter Camera (MOC) images are of high enough resolution to distinguish the largest rocks (an extremely small population several meters diameter or larger), traditionally the abundance and distribution of rocks on Mars have been inferred from thermal inertia and radar measurements, our meager ground truth sampling of landing sites, and terrestrial rock populations. In this abstract, we explore the effective thermal inertia of rocks and rock populations, interpret the results in terms of abundances and populations of potentially hazardous rocks, and conclude with interpretations of rock hazards on the Martian surface and in extremely high thermal inertia areas.

  3. Compensating for environmental variability in the thermal inertia approach to remote sensing of soil moisture

    NASA Technical Reports Server (NTRS)

    Idso, S. B.; Jackson, R. D.; Reginato, R. J.

    1976-01-01

    A procedure is developed for removing data scatter in the thermal-inertia approach to remote sensing of soil moisture which arises from environmental variability in time and space. It entails the utilization of nearby National Weather Service air temperature measurements to normalize measured diurnal surface temperature variations to what they would have been for a day of standard diurnal air temperature variation, arbitrarily assigned to be 18 C. Tests of the procedure's basic premise on a bare loam soil and a crop of alfalfa indicate it to be conceptually sound. It is possible that the technique could also be useful in other thermal-inertia applications, such as lithographic mapping.

  4. Geologic applications of thermal-inertia mapping from satellite. Final report

    SciTech Connect

    Offield, T.W.; Watson, K.; Hummer-Miller, S.

    1981-07-01

    In the Powder River Basin, Wyo., narrow geologic units having thermal inertias which contrast with their surroundings can be discriminated in optimal images. A few subtle thermal inertia anomalies coincide with areas of helium leakage believed to be associated with deep oil and gas concentrations. The most important results involved delineation of tectonic framework elements some of which were not previously recognized. Thermal and thermal inertia images also permit mapping of geomorphic textural domains. A thermal lineament appears to reveal a basement discontinuity which involves the Homestake Mine in the Black Hill, a zone of Tertiary igneous activity and facies control in oil producing horizons. Applications of these data to the Cabeza Prieta, Ariz., area illustrate their potential for igneous rock type discrimination. Extension to Yellowstone National Park resulted in the detection of additional structural information but surface hydrothermal features could not be distinguished with any confidence. A thermal inertia mapping algorithm, a fast and accurate image registration technique, and an efficient topographic slope and elevation correction method were developed.

  5. Regional thermal-inertia mapping from an experimental satellite ( Powder River basin, Wyoming).

    USGS Publications Warehouse

    Watson, K.

    1982-01-01

    A new experimental satellite has provided, for the first time, thermal data that should be useful in reconnaissance geologic exploration. Thermal inertia, a property of geologic materials, can be mapped from these data by applying an algorithm that has been developed using a new thermal model. A simple registration procedure was used on a pair of day and night images of the Powder River basin, Wyoming, to illustrate the method.-from Author

  6. The impact of martian mesoscale winds on surface temperature and on the determination of thermal inertia

    NASA Astrophysics Data System (ADS)

    Spiga, Aymeric; Forget, François; Madeleine, Jean-Baptiste; Montabone, Luca; Lewis, Stephen R.; Millour, Ehouarn

    2011-04-01

    Radiative control of surface temperature is a key characteristic of the martian environment and its low-density atmosphere. Here we show through meteorological modeling that surface temperature can be far from radiative equilibrium over numerous sloping terrains on Mars, where nighttime mesoscale katabatic winds impact the surface energy budget. Katabatic circulations induce both adiabatic atmospheric heating and enhancement of downward sensible heat flux, which then becomes comparable to radiative flux and acts to warm the ground. Through this mechanism, surface temperature can increase up to 20 K. One consequence is that warm signatures of surface temperature over slopes, observed through infrared spectrometry, cannot be systematically associated with contrasts of intrinsic soil thermal inertia. Apparent thermal inertia maps retrieved thus far possibly contain wind-induced structures. Another consequence is that surface temperature observations close to sloping terrains could allow the validation of model predictions for martian katabatic winds, provided contrasts in intrinsic thermal inertia can be ruled out. The thermal impact of winds is mostly discussed in this paper in the particular cases of Olympus Mons/Lycus Sulci and Terra Meridiani but is generally significant over any sloped terrains in low thermal inertia areas. It is even general enough to apply under daytime conditions, thereby providing a possible explanation for observed afternoon surface cooling, and to ice-covered terrains, thereby providing new insights on how winds could have shaped the present surface of Mars.

  7. Construction and interpretation of a digital inertia image. [of Pisgah Crater and Lavic Lake in Southern California

    NASA Technical Reports Server (NTRS)

    Gillespie, A. R.; Kahle, A. B.

    1977-01-01

    An image representing the thermal inertia in the vicinity of Pisgah Crater and Lavic Lake in Southern California has been generated from visible, near IR, and thermal images taken from aircraft. Construction of the thermal inertia image required radiometric calibration and geometric rectification of the acquired images as well as registration to a topographic map. The Kahle thermal model used in the construction of the thermal inertia image requires specification of albedo, topographic slope and slope azimuth, diurnal temperature range and local meteorological conditions. Albedo information was derived from the visible image; digital topographic information was computed from digitized stereo aerial photographs; and thermal ranges were calculated by subtracting the predawn from the afternoon thermal image data. Our computed values of thermal inertia were in close agreement with published values for similar surface materials. Thermal inertia provides complementary information to conventional images of reflected solar radiation for use in lithologic mapping.

  8. Measurement of the thermal inertia of the skin using successive thermograms taken at a stepwise change in ambient radiation temperature.

    PubMed

    Huang, J; Togawa, T

    1995-11-01

    Skin thermal properties are difficult to measure in vivo in the steady state because there is a constant temperature gradient across the skin surface. However, measurement of skin thermal properties is postulated in quantitative evaluation for thermographic observation. In this study, imaging of the thermal inertia of the skin was attempted by thermographic measurements at a stepwise change in ambient radiation temperature achieved by quickly switching two hoods maintained at different temperatures. Using this technique, a total of 65 thermograms were sequentially recorded at intervals of 0.5 s beginning 2 s before the stepwise change. The image of skin thermal inertia was estimated by applying statistical curve fitting at each pixel of the thermograms. In addition, the emissivity and true temperature of the skin were also determined, together with thermal inertia, in a single measurement. Measurements were made at different sites on 10 subjects. The average values of thermal inertia of normal skin were scattered throughout a range from 1.4 x 10(3) to 2.1 x 10(3) W s1/2 m-2 K-1. Investigations of the relationship between skin blood flow and thermal inertia were also made by imaging thermal inertia when skin blood flow was changed by applying a vasodilator or vasoconstrictor on the skin surface. In a comparison with the data measured by laser Doppler flowmetry, the average slope of skin blood flow versus thermal inertia was 2.88 x 10(-4) V per W s1/2 m-2 K-1, and the thermal inertia of the skin with no blood flow was 1.03 x 10(3) W s1/2 m-2 K-1. The results also show an almost linear correlation between skin blood flow and thermal inertia in each individual, but inter-individual differences were also observed. The results suggest that skin blood flow distribution can be estimated by non-contact imaging of thermal inertia. PMID:8599689

  9. Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida

    NASA Technical Reports Server (NTRS)

    Allen, L. H., Jr. (Principal Investigator); Chen, E.; Martsolf, J. D.; Jones, P. H.

    1981-01-01

    The HCMM transparency scenes for the available winter of 1978-1979 were evaluated; scenes were identified on processed magnetic tapes; other remote sensing information was identified; and a soil heat flux model with variable-depth thermal profile was developed. The Image 100 system was used to compare HCMM and GOES transparent images of surface thermal patterns. Excellent correspondence of patterns was found, with HCMM giving the greater resolution. One image shows details of thermal patterns in Florida that are attributable to difference in near surface water contents. The wide range of surface temperatures attributable to surface thermal inertia that exist in the relatively flat Florida topography is demonstrated.

  10. Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida

    NASA Technical Reports Server (NTRS)

    Allen, L. H., Jr. (Principal Investigator)

    1983-01-01

    Pairs of HCMM day-night thermal infrared (IR) data were selected during the 1978-79 winter to examine patterns of surface temperature and thermal inertia (TI) of peninsular Florida. The GOES and NOAA-6 thermal IR, as well as National Climatic Center temperatures and rainfall, were also used. The HCMM apparent thermal inertia (ATI) images closely corresponded to the general soil map of Florida, based on soil drainage classes. Areas with low ATI overlay well-drained soils, such as deep sands and drained organic soils, whereas with high ATI overlay areas with wetlands and bodies of water. The HCMM ATI images also corresponded well with GOES-detected winter nocturnal cold-prone areas. Use of HCMM data with Carlson's energy balance model showed both high moisture availability (MA) and high thermal inertia (TI) of wetland-type surfaces and low MA and low TI of upland, well-drained soils. Since soil areas with low TI develop higher temperatures during the day, then antecedent patterns of highest maximum daytime surface temperature can also be used to predict nocturnal cold-prone areas in Florida.

  11. Geologic application of thermal-inertia mapping from satellite. [Powder River Basin, Wyoming

    NASA Technical Reports Server (NTRS)

    Offield, T. W. (Principal Investigator); Miller, S. H.; Watson, K.

    1980-01-01

    The author has identified the following significant results. Two night-time thermal images of the Powder River Basin, Wyoming distinctly show a major thermal feature. This feature is substantially coincident with a drainage divide and the southward facing slope appears cooler, suggesting a lower thermal inertia. An initial examination of regional geologic maps provides no clear evidence to suggest what type of geologic feature or structure may be present, although it can be noted that its northeastern end passes directly through Lead, South Dakota where the Homestake Gold Mine is located.

  12. Physical properties of the Mars Exploration Rover landing sites as inferred from Mini-TES-derived thermal inertia

    USGS Publications Warehouse

    Fergason, R.L.; Christensen, P.R.; Bell, J.F., III; Golombek, M.P.; Herkenhoff, K. E.; Kieffer, H.H.

    2006-01-01

    The Miniature Thermal Emission Spectrometer (Mini-TES) on board the two Mars Exploration Rovers provides the first opportunity to observe thermal properties from the Martian surface, relate these properties to orbital data, and perform soil conductivity experiments under Martian conditions. The thermal inertias of soils, bedforms, and rock at each landing site were derived to quantify the physical properties of these features and understand geologic processes occurring at these localities. The thermal inertia for the. Gusev plains rock target Bonneville Beacon (???1200 J m-2 K-1 s-1/2) is consistent with a dense, basaltic rock, but the rocks at the Columbia Hills have a lower thermal inertia (???620 J m-2 K-1 s-1/2), suggesting that they have a volcaniclasic origin. Bedforms on the floors of craters at both landing sites have thermal inertias of 200 J m-2 K-1 s-1/2, consistent with a particle diameter of ???160 ??m. This diameter is comparable to the most easily moved grain size in the current atmosphere on Mars, suggesting that these bedforms may have formed under current atmospheric conditions. Along the Meridiani plains, the thermal inertia is lower than that derived from TES and Thermal Emission Imaging System (THEMIS) orbital data. This discrepancy is not well understood. Mini-TES-derived thermal inertias at Gusev along a ???2.5 km traverse follow trends in thermal inertia measured from orbit with TES and THEMIS. However, along the traverse, there are variability and mixing of particle sizes that are not resolved in the orbital thermal inertia data due to meter-scale processes that are not identifiable at larger scales. Copyright 2006 by the American Geophysical Union.

  13. Thermal Inertia, Albedo, and MOLA-derived Roughness for Terrains in the Terra Meridiani Area, Mars

    NASA Technical Reports Server (NTRS)

    Arvidson, R. E.; Deal, K.; Hynek, B. M.; Seelos, F. P., IV; Snider, N. O.; Mellon, M. T.; Garvin, J. B.

    2002-01-01

    Surface properties of layered deposits draped on dissected, cratered terrain in the Terra Meridiani area are analyzed using remote sensing data. The etched plains are cemented and differentially eroded, and the hematite plains are loose and drifting. Additional information is contained in the original extended abstract.

  14. A simple algorithm to estimate the effective regional atmospheric parameters for thermal-inertia mapping

    USGS Publications Warehouse

    Watson, K.; Hummer-Miller, S.

    1981-01-01

    A method based solely on remote sensing data has been developed to estimate those meteorological effects which are required for thermal-inertia mapping. It assumes that the atmospheric fluxes are spatially invariant and that the solar, sky, and sensible heat fluxes can be approximated by a simple mathematical form. Coefficients are determined from least-squares method by fitting observational data to our thermal model. A comparison between field measurements and the model-derived flux shows the type of agreement which can be achieved. An analysis of the limitations of the method is also provided. ?? 1981.

  15. The influence of thermal inertia on temperatures and frost stability on Triton

    NASA Technical Reports Server (NTRS)

    Spencer, John R.; Moore, Jeffrey M.

    1992-01-01

    It is presently argued, in view of (1) a thermal inertia model for the surface of Triton which (like previous ones) predicts a monotonic recession of permanent N2 deposits toward the poles and very little seasonal N2 frost in the southern hemisphere, and (2) new spectroscopic evidence for nonvolatile CO2 on Triton's bright southern hemisphere, that much of that bright southern material is not N2. Such bright southern hemisphere volatiles may allow the formation of seasonal frosts, thereby helping to explain the observed spectroscopic changes of Triton during the last decade.

  16. Mean thermal and albedo behavior of the Mars surface and atmosphere over a Martian year

    NASA Technical Reports Server (NTRS)

    Martin, T. Z.

    1981-01-01

    A Mars average data set (MADS) has been constructed from thermal and albedo measurements of the Viking Infrared Thermal Mapper; by merging information from all longitudes, and ensuring reasonably complete longitudinal sampling, a representation of mean Mars behavior is obtained. Brightness temperatures at 7, 9, 11, 15, and 20 microns and albedo information in the band 0.3-3.0 microns have been binned using 2 deg latitude strips, 24 times of day, 3 emission angle intervals, and 23 nonoverlapping solar longitude periods covering 1.43 Mars years starting at a solar longitude of 84 deg. The MADS is ideally suited to parametric study of latitudinal, diurnal, angular, and seasonal dependences. Data are presented for surface thermal and albedo behavior in clear and dusty atmospheric conditions; the thermal response of the atmospheric temperature to a major dust storm is found to be consistent with Mariner 9 data from the 1971 storm. Examples of use of the MADS, which is available through the Mars Consortium, indicate how averaged data reveal specific surface and atmospheric phenomena.

  17. Mapping the Thermal Inertia of Saturn’s Rings with Cassini CIRS

    NASA Astrophysics Data System (ADS)

    Brooks, Shawn M.; Spilker, L. J.; PIlorz, S. H.; Showalter, M. R.

    2013-10-01

    We use data from Cassini's Composite Infrared Spectrometer to map out the thermal response of Saturn's ring particles passing through Saturn's shadow and to determine variations in ring thermal inertia. CIRS records far infrared radiation in three separate detectors, each of which covers a distinct wavelength range. In this work, we analyze rings spectra recorded at focal plane 1 (FP1), as its wavelength response (16.7-1000 microns) is well suited to detecting direct thermal emission from Saturn's rings. The thermal budget of the rings is typically dominated by solar radiation. When ring particles enter Saturn’s shadow this source of energy is abruptly cut off with a consequential drop in ring temperature. Likewise, temperatures rebound when particles exit the shadow. To characterize these heating and cooling events, FP1 was repeatedly scanned across the main rings. Each scan was offset from either the ingress or egress shadow boundary by an amount corresponding to a fraction of a Keplerian orbit. By resampling these scans onto a common radial grid, we can map out the rings’ response to the abrupt changes in insolation at shadow ingress and egress. Periods near equinox represent a unique situation. During this time the Sun's disk crosses the ring plane and its rays strike the rings at zero incidence. Solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. While ring temperature variations at equinox are much more subtle, they represent temperature contrasts that vary at the unique timescale corresponding to variations in Saturn contributions to the rings’ thermal budget. By analyzing CIRS data at a variety of locations and epochs, we will map out thermal inertia across the rings and attempt to tease out structural information about the particles which comprise Saturn’s rings. This presentation will report upon our progress towards these ends. This research was carried out at the

  18. Geologic applications of thermal-inertia mapping from satellite. [Powder River, Wyoming; Cubeza Prieta, Arizona, and Yellowstone National Park

    NASA Technical Reports Server (NTRS)

    Offield, T. W. (Principal Investigator); Watson, K.; Hummer-Miller, S.

    1981-01-01

    In the Powder River Basin, Wyo., narrow geologic units having thermal inertias which contrast with their surroundings can be discriminated in optimal images. A few subtle thermal inertia anomalies coincide with areas of helium leakage believed to be associated with deep oil and gas concentrations. The most important results involved delineation of tectonic framework elements some of which were not previously recognized. Thermal and thermal inertia images also permit mapping of geomorphic textural domains. A thermal lineament appears to reveal a basement discontinuity which involves the Homestake Mine in the Black Hill, a zone of Tertiary igneous activity and facies control in oil producing horizons. Applications of these data to the Cabeza Prieta, Ariz., area illustrate their potential for igneous rock type discrimination. Extension to Yellowstone National Park resulted in the detection of additional structural information but surface hydrothermal features could not be distinguished with any confidence. A thermal inertia mapping algorithm, a fast and accurate image registration technique, and an efficient topographic slope and elevation correction method were developed.

  19. Estimation and mapping of wintertime increase in water ice content of the Martian surface soil based on seasonal Thermal Emission Spectrometer thermal inertia variations

    NASA Astrophysics Data System (ADS)

    Kuzmin, R. O.; Zabalueva, E. V.; Christensen, P. R.

    2009-04-01

    Results of the Mars Global Surveyor Thermal Emission Spectrometer (TES) thermal inertia seasonal variations analysis show significant increase of the thermal inertia during autumn-winter periods in the middle latitudes. This observed increase occurred with regular repetition during each of the three Mars years of the TES observations. Two climatic factors (atmospheric dust loading and water ice (frost) formation in the soil) might lead to the real and/or apparent seasonal increase in thermal inertia. We compare maps of summertime and wintertime thermal inertia at similarly low atmospheric dust opacity within the latitude belt ±50°, outside of the seasonal CO2 ice cover. On the basis of the results of such comparison we developed a new method for estimating and mapping the wintertime increase of the water ice within the surface soil layer corresponding to the daily thermal skin depth of 2-10 cm. We use both the nomograms of relation between the thermal inertia for dry and icy soil compiled for different water ice content and an analytical approach. Comparison of the mapped wintertime TES thermal inertia values with computed values of the parameter for icy soil at different ice amounts shows that the wintertime thermal inertia values in the latitude ranges 40°-50°N and 40°-50°S are consistent with the presence of the water ice amount in the soil from 4 up to 17 vol % (locally), whereas at lower latitudes the ice amount is mainly less than 1 vol %. Mapping results show that the zone with a soil water ice amount of >3 vol % is much more in the northern hemisphere than in the southern one.

  20. Europa's Thermal Surface from Galileo PPR

    NASA Astrophysics Data System (ADS)

    Rodriguez, N. J.; Rathbun, J. A.; Spencer, J. R.

    2009-03-01

    We present Galileo Photopolarimeter-Radiometer data of Europa and, from these, model the thermal inertia and bolometric albedo of the surface. We also derive an upper limit for detection of endogenic activity.

  1. Composition and thermal inertia of the Mawrth Vallis region of Mars from TES and THEMIS data

    NASA Astrophysics Data System (ADS)

    Michalski, Joseph R.; Fergason, Robin L.

    2009-01-01

    Clay mineral-bearing deposits previously discovered on Mars with near infrared ( λ=0.3-5 μm) remote sensing data are of major significance for understanding the aqueous history, geological evolution, and past habitability of Mars. In this study, we analyzed the thermal infrared ( λ=6-35 μm) surface properties of the most extensive phyllosilicate deposit on Mars: the Mawrth Vallis area. Clay mineral-bearing units, which in visible images appear to be relatively light-toned, layered bedrock, have thermal inertia values ranging from 150 to 460 J m -2 K -1 s -1/2. This suggests the deposits are composed of a mixture of rock with sand and dust at 100-meter scales. Dark-toned materials that mantle the clay-bearing surfaces have thermal inertia values ranging from 150 to 800, indicating variable degrees of rockiness or induration of this younger sedimentary or pyroclastic unit. Thermal Emission Spectrometer (TES) spectra of the light-toned rocks were analyzed with a number of techniques, but none of the results shows a large phyllosilicate component as has been detected in the same surfaces with near-infrared data. Instead, TES spectra of light-toned surfaces are best modeled by a combination of plagioclase feldspar, high-silica materials (similar to impure opaline silica or felsic glass), and zeolites. We propose three hypotheses for why the clay minerals are not apparent in thermal infrared data, including effects due to surface roughness, sub-pixel mixing of multiple surface temperatures, and low absolute mineral abundances combined with differences in spatial sampling between instruments. Zeolites modeled in TES spectra could be a previously unrecognized component of the alteration assemblage in the phyllosilicate-bearing rocks of the Mawrth Vallis area. TES spectral index mapping suggests that (Fe/Mg)-clays detected with near infrared data correspond to trioctahedral (Fe 2+) clay minerals rather than nontronite-like clays. The average mineralogy and geologic

  2. Thermal inertia and radar reflectivity of the Martian north polar ERG: Low-density aggregates

    NASA Technical Reports Server (NTRS)

    Herkenhoff, K. E.

    1993-01-01

    The north polar layered deposits on Mars appear to be the source of the dark material that comprises the north polar erg. The physical properties and chemical composition of the erg material therefore have important implications for the origin and evolution of the Martian layered deposits. Viking bistatic radar and infrared thermal mapping (IRTM) data indicate that the bulk density of the erg material is lower than that of the average Martian surface. These data are consistent with hypotheses involving formation of filamentary sublimation residue (FSR) particles from erosion of the layered deposits. The color and albedo of the erg and of the layered deposits, and the presence of magnetic material on Mars, suggest that the dark material is composed of low-density aggregates of magnetic dust grains, perhaps similar to FSR particles created in laboratory experiments.

  3. The polar layered deposits on Mars: Inference from thermal inertia modeling and geologic studies

    NASA Technical Reports Server (NTRS)

    Herkenhoff, K. E.

    1992-01-01

    It is widely believed that the Martian polar layered deposits record climate variations over at least the last 10 to 100 m.y., but the details of the processes involved and their relative roles in layer formation and evolution remain obscure. Weathering of the Martian layered deposits by sublimation of water ice can account for the thermal inertias, water vapor abundances, and geologic relationships observed in the Martian polar regions. The nonvolatile components of the layered deposits appears to consist mainly of bright red dust, with small amounts of dark dust. Dark dust, perhaps similar to the magnetic material found at the Viking Lander sites, may preferentially form filamentary residue particles upon weathering of the deposits. Once eroded, these particles may saltate to form the dark dunes found in both polar regions. This scenario for the origin and evolution of the dark material within the polar layered deposits is consistent with the available imaging and thermal data. Further experimental measurements of the thermophysical properties of magnetite and maghemite under Martian conditions are needed to better test this hypothesis.

  4. Critical analysis of the thermal inertia approach to map soil water content under sparse vegetation and changeable sky conditions

    NASA Astrophysics Data System (ADS)

    Maltese, Antonino; Capodici, Fulvio; Corbari, Chiara; Ciraolo, Giuseppe; La Loggia, Goffredo; Sobrino, José Antonio

    2012-09-01

    The paper reports a critical analysis of the thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data. The study area is an experimental area located in Barrax (Spain). Field data were acquired within the Barrax 2011 research project. AHS airborne images including VIS/NIR and TIR bands were acquired both day and night time by the INTA (Instituto Nacional de Técnica Aeroespacial) between the 11th and 13rd of June 2011. Images cover a corn pivot surrounded by bare soil, where a set of in situ data have been collected previously and simultaneously to overpasses. To validate remotely sensed estimations, a preliminary proximity sensing set up has been arranged, measuring spectra and surface temperatures on transects by means of ASD hand-held spectroradiometer and an Everest Interscience radiometric thermometer respectively. These data were collected on two transects: the first one on bare soil and the second from bare to sparsely vegetated soil; soil water content in both transects ranged approximately between field and saturation values. Furthermore thermal inertia was measured using a KD2Pro probe, and surface water content of soil was measured using FDR and TDR probes. This ground dataset was used: 1) to verify if the thermal inertia method can be applied to map water content also on soil covered by sparse vegetation, and 2) to quantify a correction factor of the downwelling shortwave radiation taking into account sky cloudiness effects on thermal inertia assessment. The experiment tests both Xue and Cracknell approximation to retrieve the thermal inertia from a dumped value of the phase difference and the three-temperature approach of Sobrino to estimate the phase difference spatial distribution. Both methods were then applied on the remotely sensed airborne images collected during the following days, in order to obtain the spatial distribution of the surface soil moisture on bare soils and

  5. Evaluation of hcmm satellite data for estuarine tidal circulation patterns and thermal inertia soil moisture measurements. interim; final report

    SciTech Connect

    Wiesnet, D.R.; Mcginnis, D.F., Jr.; Matson, M.; Pritchard, J.A.

    1981-06-01

    Digital thermal maps of the Cooper River (SC) and the Potomac River estuaries were prepared from heat capacity mapping radiometer (HCMR) tapes. Tidal phases were correctly interpreted and verified. Synoptic surface circulation patterns were charted by location thermal fronts and water mass boundaries within the estuaries. Thermal anomalies were detected adjacent of a conventional power plant on the Potomac. Under optimum conditions, estuaries as small as the Cooper River can be monitored for generalized thermal/tidal circulation patterns by the HCMM-type IR sensors. The HCMM thermal inertia approach to estimating soil moisture at the Luverne (MN) test site was found to be unsatisfactory as a NESS operational satellite technique because of cloud cover interference. Thermal-IR data show similar structure of the Baltimore and Washington heat islands when compared to NOAA AVHHR thermal-IR data. Thermal anomalies from the warm water discharge water of a nuclear power plant were mapped in Lake Anna, Virginia.

  6. The feasibility of thermal inertia mapping for detection of perched water tables in semi-arid irrigated lands

    NASA Technical Reports Server (NTRS)

    Ezra, C. E.; Estes, J. E.; Bonn, F.

    1982-01-01

    The thermal inertia mapping remote sensing technique is evaluated as a potential method for delineating areas of shallow perched water tables and related salinization problems on a regional basis. This method for detecting shallow water tables is based on the existence of significant differences in soil thermal properties between wet and dry soil profiles. Ground observations were conducted at two different test sites in California along the flight line, with one site located in a perched water table area and the other site in a well drained area. Measurements were taken hourly during a four day period (two days before and two days after the flight) for variables such as radiometric, meteorologic, soil moisture and temperature profiles, and surface characteristics. Results indicate that it is not feasible using present apparent thermal inertia remote sensing techniques to reliably delineate regional patterns of very shallow water tables due to the complex environmental system. However, some features within specific fields which may be directly related to the local presence of shallow water tables, such as differences in evaporative cooling due to soil moisture effects between and within fields, can be detected using the thermal inertia technique.

  7. Thermal properties of 433 Eros

    NASA Technical Reports Server (NTRS)

    Lebofsky, L. A.; Rieke, G. H.

    1979-01-01

    Radiometric and reflected light observations of 433 Eros at high time resolution, high accuracy, and broad spectral coverage are reported. A thermal inertia model is used to estimate the thermal inertia, albedo, and size of Eros. An albedo of 0.125 plus or minus 0.025 with axes of 39.3 plus or minus 2.0 x 16.1 plus or minus 0.8 km is found. The estimate of the albedo is about 30% lower than previous estimates.

  8. Mapping soil water content under sparse vegetation and changeable sky conditions: comparison of two thermal inertia approaches

    NASA Astrophysics Data System (ADS)

    Maltese, Antonino; Capodici, Fulvio; Ciraolo, Giuseppe; La Loggia, Goffredo

    2013-01-01

    A critical analysis of a thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data is reported. The study area is an experimental field located in Barrax, Spain. In situ data were acquired within the Barrax 2011 research project. An advanced hyperspectral scanner airborne imager provides images in the visible/near-infrared and thermal infrared bands. Images were acquired both in day and night times by the Instituto Nacional de Técnica Aeroespacial between 12th and 13th of June 2011. The scene covers a corn irrigation pivot surrounded by bare soil, where a set of in situ data have been collected both previously and simultaneously to overpasses. To validate remotely sensed estimations, an ad hoc dataset has been produced by measuring spectra, radiometric temperatures, surface soil water content, and soil thermal properties. These data were collected on two transects covering bare and sparsely vegetated soils. This ground dataset was used (1) to verify if a thermal inertia method can be applied to map the water content on soil covered by sparse vegetation and (2) to quantify a correction factor accounting for solar radiation reduction due to sky cloudiness. The experiment intended to test a spatially constant and a spatially distributed approach to estimate the phase difference. Both methods were then applied to the airborne images collected during the following days to obtain the spatial distribution of surface soil water content. Results confirm that the thermal inertia method can be applied to sparsely vegetated soil characterized by low fractional cover if the solar radiation reaching the ground is accurately estimated. A spatially constant value of the phase difference allows a good assessment of thermal inertia, whereas the comparison with the three-temperature approach did not give conclusive responses. Results also show that clear sky, only at the time of the acquisition, does not provide

  9. Geologic application of thermal inertia imaging using HCMM data. [Death Valley and Pisgah Crater, California and Goldfield, Nevada

    NASA Technical Reports Server (NTRS)

    Paley, H. N.; Kahle, A. B. (Principal Investigator)

    1980-01-01

    During the July to September 1980 quarter the final tapes were received completing the order and preliminary processing was done. Thermal Inertia images for each of the three test sites, Death Valley and Pisgah Crater, California and Goldfield, Nevada were created using registered HCMM day/night pairs and the JPL model. A comprehensive study and analysis of the geologic application of all acquired HCMM data is in progress.

  10. Soil moisture derived using two apparent thermal inertia functions over Canterbury, New Zealand

    NASA Astrophysics Data System (ADS)

    Sohrabinia, Mammatt; Rack, Wolfgang; Zawar-Reza, Peyman

    2014-01-01

    The near-surface soil moisture (SM) is an important property of the soil that can be studied from satellite remote sensing observations over a large spatial domain. This research provides an estimate on the accuracy of SM retrieved from satellite land surface temperature (LST) observations over the Canterbury Plains, New Zealand. The apparent thermal inertia (ATI) method with two approaches (ATI1 and ATI2) was applied to derive the near-surface SM from the moderate resolution imaging spectroradiometer (MODIS) LST product. The in-situ measurements of SM and rainfall data at six sites across the study area were used as reference. The analysis was conducted over two periods, a short period of four months and a longer period of three years. SM simulations by the weather research and forecasting (WRF) model were used in the analysis for the shorter period. Overall, SM based on ATI2 showed a slightly higher correlation with the in-situ measurements (ρ¯=0.66) than ATI1 (ρ¯=0.63). The correlation, in general, was higher for the WRF simulations (ρ¯=0.81). Both functions performed better during summer compared to winter, but overall, ATI2 showed lower mean errors (ME≈-15 m3.m-3 volumetric SM) compared to ATI1 (ME≈-20 m3.m-3) at most of the sites. Additionally, seasonal variations of SM were better detected by ATI2 than ATI1, and the effects of precipitation were detected on more occasions by the ATI2 function. We conclude that ATI2 function can be used to estimate the near-surface SM over a large area from the MODIS LST time series if a few representative reference stations are available.

  11. Regional-scale estimates of surface moisture availability and thermal inertia using remote thermal measurements

    NASA Technical Reports Server (NTRS)

    Carlson, T. N.

    1986-01-01

    A review is presented of numerical models which were developed to interpret thermal IR data and to identify the governing parameters and surface energy fluxes recorded in the images. Analytic, predictive, diagnostic and empirical models are described. The limitations of each type of modeling approach are explored in terms of the error sources and inherent constraints due to theoretical or measurement limitations. Sample results of regional-scale soil moisture or evaporation patterns derived from the Heat Capacity Mapping Mission and GOES satellite data through application of the predictive model devised by Carlson (1981) are discussed. The analysis indicates that pattern recognition will probably be highest when data are collected over flat, arid, sparsely vegetated terrain. The soil moisture data then obtained may be accurate to within 10-20 percent.

  12. On the Correction of the Melting Curve of the Eutectic Co-C for the Effect of the Thermal Inertia of the Furnace

    NASA Astrophysics Data System (ADS)

    Bloembergen, P.; Battuello, M.; Girard, F.; Machin, G.; Wright, L.

    2016-04-01

    This paper considers the influence of the thermal inertia of the furnace on the shape of the melting curve of the eutectic Co-C. To this end, melting experiments have been performed in a uniform three-zone furnace, with an inherent substantial thermal inertia. The thermal inertia has been quantified by measuring the step-response of the furnace with the sample in its solid state, just below its melting temperature. From the analysis of the effect of the thermal inertia of the furnace, it turned out that during melting the temperature distribution within the furnace, surrounding the crucible, is bound to be in a non-stationary state. This provided the key to properly finalizing the correction to be applied. The shape of the corrected curve differs considerably from that of the curve, as measured, in that the former shows a flatter melting plateau, and a larger curvature on the way down to the solidus point. As regards the liquidus temperature T_{liq}—of major interest in the characterization of the transition temperature of high-temperature fixed points—it is demonstrated that the thermal inertia of the furnace shows a kind of self-compensating mechanism. But the effects of the thermal inertia of the furnace on the parameters defining the Scheil fit, involved in the correction procedure, were considerable.

  13. A validation of a thermal inertia approach to map soil water content on soils characterized by low fractional cover

    NASA Astrophysics Data System (ADS)

    Maltese, Antonino; Capodici, Fulvio; La Loggia, Goffredo; Corbari, Chiara; Mancini, Marco

    2013-10-01

    The assessment of the spatial distribution of soil water content could improve the effectiveness of agro-hydrological models. Although it is possible to retrieve the spatial distribution of the soil water content using thermal inertia, the main limit is its applicability to bare soils only. Recently, a variation of the thermal inertia approach has been setup also on vegetated soils characterized by low fractional cover. In particular, the methodology proposes to attenuate the solar radiation at the top of the canopy to the one reaching the soil trough an extinction factor. In situ data were acquired in June 2011 and July 2012 over two fields of maize and sunflowers; both were at their early growing stages. An airborneplatform provided images in the visible/near infrared and thermal infrared, both in day and night time. Results of the 2011 experiment demonstrated that the vegetation cover correction is required even with low fractional cover; indeed, not applying this correction would results in strong overestimation. The 2012 experiment (REFLEX) further validates the model on an independent dataset, thus, confirming the reliability of the methodology. Furthermore, a spatial resolution analysis highlighted that retrievals at low spatial resolution best compares with in situsoil water content than those obtained at high-resolution. Finally, the availability of a thermal image acquired after irrigating demonstrated the unreliability of the method when soil water content significantly changes between the two thermal acquisitions.

  14. Thermal-Infrared Surveys of Near-Earth Object Diameters and Albedos with Spitzer and IRTF/MIRSI

    NASA Astrophysics Data System (ADS)

    Mommert, Michael; Trilling, David; Hora, Joseph L.; Chesley, Steven; Emery, Josh; Fazio, Giovanni; Harris, Alan W.; Moskovitz, Nick; Mueller, Michael; Smith, Howard

    2015-08-01

    More than 12000 Near-Earth Objects (NEOs) have been discovered over the past few decades and current discovery surveys find on average 4 new NEOs every night. In comparison to asteroid discovery, the physical characterization of NEOs lags far behind: measured diameters and albedos exist only for roughly 10% of all known NEOs. We describe a current and a future observing program that provide diameter and albedo measurements of a large number of NEOs.In our Spitzer Space Telescope Exploration Science program 'NEOSurvey', we are performing a fast and efficient flux-limited survey in which we measure the diameters and albedos of ~600 NEOs in a total of 710 hrs of observing time. We measure the thermal emission of our targets at 4.5 micron and combine these measurements with optical data in a thermal model. Our diameters and albedos come with highly realistic uncertainties that account for a wide range of potential asteroid properties. Our primary goal is to create a large and uniform catalog of NEO properties, including diameters, albedos, and flux density data. This catalog is publicly accessible and provides the latest results usually within 2 weeks after the observation.Starting in 2016, we will also make use of the refurbished and recommissioned MIRSI mid-infrared imaging camera on NASA's InfraRed Telescope Facility (IRTF) to derive the diameters and albedos of up to 750 NEOs over a period of 3 yrs. MIRSI will be equipped with an optical camera that will allow for simultaneous optical imaging, which will improve our thermal modeling results. With MIRSI, we will focus on newly discovered NEOs that are close to Earth and hence relatively bright.The results from both programs, together with already exisiting diameter and albedo results from the literature, will form the largest database of NEO physical properties available to date. With this data set, we will be able to refine the size distribution of small NEOs and the corresponding impact frequency, and compare the

  15. Geologic application of thermal inertia imaging using HCMM data. [Walker Lane, Nevada; San Rafael, Utah; and Death Valley and Pisgah Crater, Lavic Lake Region, California

    NASA Technical Reports Server (NTRS)

    Kahle, A. B.; Schieldge, J. P.; Abrams, M. J.; Alley, R. E.; Levine, C. J. (Principal Investigator)

    1981-01-01

    Three test sites in the western US were selected to discriminate among surface geologic materials on the basis of their thermal properties as determined from HCMM data. Attempts to determine quantitatively accurate thermal inertia values from HCMM digital data met with only partial success due to the effects of sensor miscalibrations, radiative transfer in the atmosphere, and varying meteorology and elevation across a scene. In most instances, apparent thermal inertia was found to be an excellent qualitative representation of true thermal inertia. Computer processing of digital day and night HCMM data allowed construction of geologically useful images. At some test sites, more information was provided by data than LANDSAT data. Soil moisture effects and differences in spectrally dark materials were more effectively displayed using the thermal data.

  16. Development of a dynamic thermal system model for a low inertia reheating furnace: Comparison of test data with predictions

    SciTech Connect

    Yoshino, H.; Viskanta, R.

    1999-07-01

    The batch, indirectly-fired furnace, called low inertia furnace (LIF), is simulated using a dynamic thermal model. The load consisting of a basket filled with small parts is placed on the hearth (bottom) of the furnace, and the LIF is heated by flat radiant heaters (FRH) which are installed on the sidewalls, the ends and the roof of the furnace. Transient heat transfer in the load, walls, roof and gas are modeled. Natural gas is burned in the heaters, but the combustion and heat transfer processes in the FRHs are not treated. Instead, measured heater surface temperature vs. time is used to drive the dynamic thermal system model. The mathematical model of the furnace integrates the models for heat transfer within the enclosure and walls with the porous medium load model. Radiation heat exchange between the load, the radiant heaters and the furnace walls are analyzed using the radiosity method. Heat transfer in the porous medium is by conduction, radiation and convection between the solid and gas phases. Radiation within the load is considered to be a diffusion process. Two different porous medium models for the load are developed, and the model predictions are compared with test data obtained by the Institute of Gas Technology on a low inertia indirectly-fired furnace. Parametric calculations are performed to identify the important model parameters and validate the models.

  17. Temporal and spatial mapping of atmospheric dust opacity and surface albedo on Mars

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Clancy, R. T.; Gladstone, G. R.; Martin, T. Z.

    1993-01-01

    The Mariner 9 and Viking missions provided abundant evidence that eolian processes are active over much of the surface of Mars. Past studies have demonstrated that variations in regional albedo and wind streak patterns are indicative of sediment transport through a region, while thermal inertia data (derived from the Viking Infrared Thermal Mapper (IRTM) datasets) are indicative of the degree of surface mantling by dust deposits. We are making use of the method developed by T. Z. Martin to determine dust opacity from IRTM thermal observations. We have developed a radiative transfer model that allows corrections for the effects of atmospheric dust loading on observations of surface albedo to be made. This approach to determining 'dust-corrected surface albedo' incorporates the atmospheric dust opacity, the single-scattering albedo and particle phase function of atmospheric dust, the bidirectional reflectance of the surface, and accounts for variable lighting and viewing geometry.

  18. Determining soil moisture and sediment availability at White Sands Dune Field, New Mexico, from apparent thermal inertia data

    NASA Astrophysics Data System (ADS)

    Scheidt, Stephen; Ramsey, Michael; Lancaster, Nicholas

    2010-06-01

    Determinations of soil moisture and sediment availability in arid regions are important indicators of local climate variability and the potential for future dust storm events. Data from the Advanced Spaceborne Thermal Emission and Reflection (ASTER) radiometer were used to derive the relationships among potential soil erosion, soil moisture, and thermal inertia (TI) at the spatial scale of aeolian landforms for the White Sands Dune Field between May 2000 and March 2008. Land surface apparent thermal inertia (ATI) data were used to derive an approximation of actual TI in order to estimate the wind threshold velocity ratio (WTR). The WTR is a ratio of the wind velocity thresholds at which soil erosion occurs for wet soil versus dry soil. The ASTER-derived soil moisture retrievals and the changes through time at White Sands were interpreted to be driven primarily by precipitation, but the presence of a perched groundwater table may also influence certain areas. The sediment availability of dunes, active playa surfaces and the margin of the alluvial fans to the west were determined to be consistently higher than the surrounding area. The sediment availability can be primarily explained by precipitation events and the number of dry days prior to the data acquisition. Other factors such as vegetation and the amount of surface crusting may also influence soil mobility, but these were not measured in the field. This approach showed the highest modeled sediment availability values just days prior to the largest dust emission event at White Sands in decades. Such an approach could be extended to a global monitoring technique for arid land systems that are prone to dust storms and for other regional land surface studies in the Sahara.

  19. Mars Albedo

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These two views of Mars are derived from the MGS Thermal Emission Spectrometer (TES) measurements of global broadband (0.3 - 3.0 microns) visible and near-infrared reflectance, also known as albedo. The range of colors are in dimensionless units. The values are the ratio of the amount of electromagnetic energy reflected by the surface to the amount of energy incident upon it from the sun (larger values are brighter surfaces).

    The TES instrument was built by Santa Barbara Remote Sensing and is operated by Philip R. Christensen, of Arizona State University, Tempe, AZ.

  20. SATELLITE ESTIMATION OF THE SURFACE ENERGY BALANCE, MOISTURE AVAILABILITY AND THERMAL INERTIA

    EPA Science Inventory

    A method for inferring the distribution of surface heat and evaporative fluxes and the ground moisture availability and thermal inertial (ground conductive capacity) is used to analyze two urbanized areas, Los Angeles and St. Louis. The technique employs infrared satellite temper...

  1. A case for using ground-based thermal inertia measurements to detect Martian caves.

    PubMed

    Groemer, Gernot; Foresta, Luca; Turetschek, Thomas; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Frischauf, Norbert; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ragonig, Christoph; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sams, Sebastian; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Soucek, Alexander; Stadler, Andrea; Stummer, Florian; Stumptner, Willibald; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    Martian caves are regarded as one of the most interesting locations in which to search for life on the planet. Data obtained during the MARS2013 expedition at Hamar Laghdad Ridge in the Tafilalt region of Morocco indicate that even small cavities can display thermal behavior that is characteristic for caves. For example, temperature in a cavity equaled 14°C±0.1°C before sunrise, which was higher than the temperature of the ambient air (10°C±0.1°C) and proximate rocks (9°C±0.1°C) at the same time. Within 30 min after sunrise, when the temperature of surrounding rocks corresponded to 15°C, this thermal relationship reversed. Measurements were conducted under simulated spaceflight conditions, including near-real-time interpretation of data that were acquired in a complex flight planning environment. We conclude that using ground-based thermal contrast measurements, in 7-14 μm band before and after sunset, is an effective method for Mars astronauts to identify caves, possibly superior to usage of space-based or ground-penetrating data. PMID:24823802

  2. Prediction of temperature and thermal inertia effect in the maturation stage and stockpiling of a large composting mass

    SciTech Connect

    Barrena, R.; Canovas, C.; Sanchez, A. . E-mail: asanchez@eupma.uab.es

    2006-07-01

    A macroscopic non-steady state energy balance was developed and solved for a composting pile of source-selected organic fraction of municipal solid waste during the maturation stage (13,500 kg of compost). Simulated temperature profiles correlated well with temperature experimental data (ranging from 50 to 70 deg. C) obtained during the maturation process for more than 50 days at full scale. Thermal inertia effect usually found in composting plants and associated to the stockpiling of large composting masses could be predicted by means of this simplified energy balance, which takes into account terms of convective, conductive and radiation heat dissipation. Heat losses in a large composting mass are not significant due to the similar temperatures found at the surroundings and at the surface of the pile (ranging from 15 to 40 deg. C). In contrast, thermophilic temperature in the core of the pile was maintained during the whole maturation process. Heat generation was estimated with the static respiration index, a parameter that is typically used to monitor the biological activity and stability of composting processes. In this study, the static respiration index is presented as a parameter to estimate the metabolic heat that can be generated according to the biodegradable organic matter content of a compost sample, which can be useful in predicting the temperature of the composting process.

  3. Use of Satellite Data Assimilation to Infer Land Surface Thermal Inertia

    NASA Technical Reports Server (NTRS)

    Lapenta, William; McNider, Richard T.; Biazar, Arastoo; Suggs, Ron; Jedlovec, Gary; Dembek, Scott

    2002-01-01

    There are two important but observationally uncertain parameters in the grid averaged surface energy budgets of mesoscale models - surface moisture availability and thermal heat capacity. A technique has been successfully developed for assimilating Geostationary Operational Environmental Satellite (GOES) skin temperature tendencies during the mid-morning time frame to improve specification of surface moisture. In a new application of the technique, the use of satellite skin temperature tendencies in early evening is explored to improve specification of the surface thermal heat capacity. Together, these two satellite assimilation constraints have been shown to significantly improve the characterization of the surface energy budget of a mesoscale model on fine spatial scales. The GOES assimilation without the adjusted heat capacity was run operationally during the International H2O Project on a 12-km grid. This paper presents the results obtained when using both the moisture availability and heat capacity retrievals in concert. Preliminary results indicate that retrieved moisture availability alone improved the verification statistics of 2-meter temperature and dew point forecasts. Results from the 1.5 month long study period using the bulk heat capacity will be presented at the meeting.

  4. Evaluation of thermal data for geologic applications

    NASA Technical Reports Server (NTRS)

    Kahle, A. B.; Palluconi, F. D.; Levine, C. J.; Abrams, M. J.; Nash, D. B.; Alley, R. E.; Schieldge, J. P.

    1982-01-01

    Sensitivity studies using thermal models indicated sources of errors in the determination of thermal inertia from HCMM data. Apparent thermal inertia, with only simple atmospheric radiance corrections to the measured surface temperature, would be sufficient for most operational requirements for surface thermal inertia. Thermal data does have additional information about the nature of surface material that is not available in visible and near infrared reflectance data. Color composites of daytime temperature, nighttime temperature, and albedo were often more useful than thermal inertia images alone for discrimination of lithologic boundaries. A modeling study, using the annual heating cycle, indicated the feasibility of looking for geologic features buried under as much as a meter of alluvial material. The spatial resolution of HCMM data is a major limiting factor in the usefulness of the data for geologic applications. Future thermal infrared satellite sensors should provide spatial resolution comparable to that of the LANDSAT data.

  5. Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida. [The Everglades agricultural area, Lake Okeechobee, and the Suwanee River basin

    NASA Technical Reports Server (NTRS)

    Allen, L. H., Jr. (Principal Investigator); Chen, E.; Martsolf, J. D.; Jones, P. H.

    1981-01-01

    Transparencies, prints, and computer compatible tapes of temperature differential and thermal inertia for the winter of 1978 to 1979 were obtained. Thermal inertial differences in the South Florida depicted include: drained organic soils of the Everglades agricultural area, undrained organic soils of the managed water conservation areas of the South Florida water management district, the urbanized area around Miami, Lake Okeechobee, and the mineral soil west of the Everglades agricultural area. The range of wetlands and uplands conditions within the Suwanee River basin was also identified. It is shown that the combination of wetlands uplands surface features of Florida yield a wide range of surface temperatures related to wetness of the surface features.

  6. Program for Computing Albedo

    NASA Technical Reports Server (NTRS)

    Justus, Carl G.

    2003-01-01

    Simple Thermal Environment Model (STEM) is a FORTRAN-based computer program that provides engineering estimates of top-of-atmosphere albedo and outgoing long-wave radiation (OLR) for use in analyzing thermal loads on spacecraft near Earth. The thermal environment of a spacecraft is represented in STEM as consisting of direct solar radiation; short-wave radiation reflected by the atmosphere of the Earth, as characterized in terms of the albedo of the Earth; and OLR emitted by the atmosphere of the Earth. STEM can also address effects of heat loads internal to a spacecraft. Novel features of STEM include (1) the use of Earth albedo and OLR information based on time series of measurements by Earth Radiation Budget Experiment satellites in orbit; (2) the ability to address thermal time constants of spacecraft systems by use of albedo and OLR values representing averages over a range of averaging times; and (3) the ability to address effects, on albedo and OLR values, of satellite orbital inclination, the angle between the plane of a spacecraft orbit and the line between the centers of the Earth and Sun, the solar zenith angle, and latitude.

  7. Albedo Boundary

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-510, 11 October 2003

    The sharp, nearly straight line that runs diagonally across the center of this April 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image is an albedo boundary. Albedois a term that refers to reflectance of sunlight. A surface with a low albedo is one that appears dark because it reflects less light than a high albedo (bright) surface. On Mars, albedo boundaries occur between two materials of differing texture, particle size, or composition, or some combination of these three factors. The boundary shown here is remarkable because it is so sharp and straight. This is caused by wind. Most likely, the entire surface was once covered with the lower-albedo (darker) material that is now seen in the upper half of the image. At some later time, wind stripped away this darker material from the surfaces in the lower half of the image. The difference in albedo here might be related to composition, and possibly particle size. This picture is located near the southwest rim of Schiaparelli Basin at 5.5oS, 345.9oW. The picture covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the left.

  8. Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida. [Everglades agricultural area and the west north central peninsula

    NASA Technical Reports Server (NTRS)

    Allen, L. H., Jr. (Principal Investigator); Chen, E.; Martsolf, J. D.; Jones, P. H.

    1981-01-01

    Surface temperatures derived from HCMM data were compared with to those obtained by GOES satellite and the apparent thermal inertia (ATI) calculated. For two dates, the HCMM temperatures appear to be about 5 C lower than the GOES temperatures. The ATI for excessively-drained to well-drained mineral soils was greater than for drained organic soils possibly because of long periods of low rainfall during late 1980 and early 1981. Organic soils cropped to sugar cane showed lower ATI after a severe killing freeze. With dead leaves, there was less transpiration and more solar radiation probably reached the dark soil surface. This would explain the larger diurnal temperature amplitude observed.

  9. Separation of thermal inertia and roughness effects from Dawn/VIR measurements of Vesta surface temperatures in the vicinity of Marcia Crater

    NASA Astrophysics Data System (ADS)

    Keihm, S.; Tosi, F.; Capria, M. T.; De Sanctis, M. C.; Longobardo, A.; Palomba, E.; Russell, C. T.; Raymond, C. A.

    2015-12-01

    A physical model of small scale roughness has been applied to the analyses of VIR (Visible InfraRed mapping spectrometer) - measured surface temperatures in the Marcia Crater region of asteroid Vesta. Model-generated surface temperatures which include the effects of minicrater-induced flux enhancements and viewing geometry are compared with the measured surface temperature dependence on solar incidence and emission angles. Results indicate that an extremely low thermal inertia (I = <5 J K-1 m-2 s-1/2) and high roughness (rms slopes ∼35°) characterizes almost all of the areas in and around Marcia Crater. The one clear exception is the relatively cool pitted terrain region within Marcia Crater which requires either a higher thermal inertia value (I ∼ 10) or significantly less roughness to match the VIR data. The I ∼ 5 finding is the lowest value found for the regolith of any airless body in the inner Solar System and is difficult to reproduce in either laboratory measurements or theoretical models of the thermal conductivity of dry granular materials in vacuum.

  10. Estimating Spatial Disturbution of Surface Soil Mositure Conditions Using a Downscale Technique with Thermal Inertia Retrieved from AMSR2 Soil Moisture Products

    NASA Astrophysics Data System (ADS)

    Matsushima, D.; Kimura, R.

    2014-12-01

    We examined that a method for estimating spatial distribution of surface soil moisture conditions with a fine grid scale. The AMSR2 soil moisture products which have been produced by Japan Aerospace Exploration Agency (JAXA) with a coarse grid scale (50 km) were downscaled by a spatial distribution of thermal inertia (3 km), which was retrived from a two-source linear surface heat budget model using an optimization method in which the input variables such as MODIS surface temperature, insolation retrieved from a geostationary satellite, and surface meterological data were incorporated. The downscale technique employed a characteristic that thermal inertia is almost proportional to volumetric soil moisture content, which was found in results of some field experiments. This downscale technique was applied to the AMSR2 products of summer season of central Mongolia where typical and dry steppe were dominated. A preliminary result of the downscaling technique showed fairly good result that the values of downscaled soil moisture were varied in response to rainfall events at some grids where meteorological stations existed, while the values of AMSR2 were not significantly changed.

  11. A simulation model of temperature transitory on rocks having different thermal inertia. Analysis of the theoretical capacity of rock discrimination by remote sensing data

    NASA Technical Reports Server (NTRS)

    Cassinis, R. (Principal Investigator); Tosi, N.

    1980-01-01

    The possibility of identifying ground surface material by measuring the surface temperature at two different and significant times of the day was investigated for the case of hypothetical island whose rocky surface contained no vegetation and consisted of dolomite, clay, and granite. The thermal dynamics of the soil surface during a day in which atmospheric conditions were average for a latitude of about 40 deg to 50 deg were numerically simulated. The line of separation between zones of different materials was delineated by the range of temperature variation. Results show that the difference between maximum and minimum value of the temperature of ground surface during the day is linked to the thermal inertia value of the material of which the rock is formed.

  12. Global Albedo

    Atmospheric Science Data Center

    2013-04-19

    ... to one in the visible region of the solar spectrum whereas deep clean ocean water has an albedo that is close to zero. Five years of ... Atmospheric Science Data Center's  MISR Level 3 Imagery  web site. The Multi-angle Imaging SpectroRadiometer observes the daylit ...

  13. Temporal and spatial mapping of surface albedo and atmospheric dust opacity on Mars

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Clancy, R. T.; Gladstone, G. R.

    1993-01-01

    The Mariner 9 and Viking provided abundant evidence that eolian processes are active over much of the surface of Mars. Past studies have demonstrated that variations in regional albedo and wind-streak patterns are indicative of sediment transport through a region, while thermal inertia data (derived from the Viking Infrared Thermal Mapper (IRTM) dataset) are indicative of the degree of surface mantling by dust deposits. The visual and thermal data are therefore diagnostic of whether net erosion or deposition of dust-storm fallout is taking place currently and whether such processes have been active in a region over the long term. These previous investigations, however, have not attempted to correct for the effects of atmospheric dust loading on observations of the martian surface, so quantitative studies of current sediment transport rates have included large errors due to uncertainty in the magnitude of this 'atmospheric component' of the observations. We have developed a radiative transfer model that allows the atmospheric dust opacity to be determined from IRTM thermal observations. Corrections for the effects of atmospheric dust loading on observations of surface albedo can also be modeled. This approach to determining 'dust-corrected surface albedo' incorporates the atmospheric dust opacity, the single-scattering albedo and particle phase function of atmospheric dust, and the bidirectional reflectance of the surface, and it accounts for variable lighting and viewing geometry.

  14. Thermal cracking of CO2 slab ice as the main driving force for albedo increase of the martian seasonal polar caps

    NASA Astrophysics Data System (ADS)

    Philippe, S.; Schmitt, B.; Beck, P.; Brissaud, O.

    2015-10-01

    Understanding the microphysical processes occuring on the Martian seasonal cap is critical since their radiative properties can affect the martian climate. A well documented phenomenom is the albedo increase of the Martian seasonal caps during spring, Fig.1. There are a lot of hypotheses that have been proposed as an explanation for this observation : the decrease of the CO2 grain size [2], a cleaning process of the CO2 slab that would imply either the sinking or the ejection of the dust contained in its volume ([1], [2], [5]), a water-layer accumulation on the top of the slab [5], the role played by aerosols [2] etc ... So far, no experimental simulations have been realized to discriminate between these processes. We designed an experiment to investigate the hypothesis of CO2 ice grain size decrease through thermal cracking as well as that of dust segregation as the possible reasons for albedo increase.

  15. Global Albedo

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A new sensor aboard NASA?s Terra satellite is now collecting the most detailed and accurate measurements ever made of how much sunlight the Earth?s surface reflects back up into the atmosphere. By quantifying precisely our planet?s reflectivity, or albedo, the Moderate Resolution Imaging Spectroradiometer (MODIS) is helping scientists better understand and predict how various surface features influence both short-term weather patterns as well as longer-term climate trends. (Click to read the press release.) The colors in this image emphasize the albedo over the Earth?s land surfaces, ranging from 0.0 to 0.4. Areas colored red show the brightest, most reflective regions; yellows and greens are intermediate values; and blues and violets show relatively dark surfaces. White indicates where no data were available, and no albedo data are provided over the oceans. This image was produced using data composited over a 16-day period, from April 7-22, 2002. Image courtesy Crystal Schaaf, Boston University, based upon data processed by the MODIS Land Science Team

  16. A thermal model of Rosetta/ROSINA/DFMS to assess the effects of solar illumination and thermal inertia of the mass spectrometer on mass spectra at 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    De Keyser, Johan; Gibbons, Andrew; Neefs, Eddy; Equeter, Eddy; Dhooghe, Frederik; Maggiolo, Romain; Cessateur, Gaël; Gunell, Herbert; Altwegg, Kathrin; Berthelier, Jean-Jacques; Briois, Christelle; Calmonte, Ursina; Combi, Michael R.; Fiethe, Björn; Fuselier, Stephen; Gombosi, Tamas; Hässig, Myrttha; Le Roy, Léna; Rubin, Martin; Sémon, Thierry

    2016-04-01

    The coma composition of comet 67P/Churyumov-Gerasimenko is being analysed in detail with the high mass resolution Double Focussing Mass Spectrometer (DFMS) that is part of the ROSINA instrument suite on board of the Rosetta spacecraft. The Rosetta spacecraft - and DFMS in particular - experiences changing behaviour as the temperature varies with illumination and distance from the Sun. This contribution highlights these changes and their practical consequences for the interpretation of the DFMS mass spectra. A thermal model is presented that addresses thermal behaviour on a long time scale, related to instrument illumination and thermal gradients inside DFMS, and on a short time scale, related to transients after on/off cycling of the instrument and thermal inertia. Both issues adversely affect the problem of establishing a proper instrument mass calibration.

  17. Identifying ephemeral and perennial stream reaches using apparent thermal inertia for an ungauged basin: The Rio Salado, Central New Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Night and day temperature images from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing images are used to identify ephemeral and perennial stream reaches for use in the calibration of an integrated hydrologic model of an ungauged basin. The concept is based on a...

  18. Celestial body irradiance determination from an underfilled satellite radiometer: application to albedo and thermal emission measurements of the Moon using CERES.

    PubMed

    Matthews, Grant

    2008-09-20

    The Clouds and the Earth's Radiant Energy System (CERES) is a program that measures the Earth radiation budget (ERB) from two polar orbiting satellite platforms. CERES radiometers are designed to make stable broadband measurements of scattered solar and emitted thermal radiative flux leaving Earth with an accuracy of 1% or better. Using versatile and programmable scan modes, it is also possible for every CERES instrument to view the Moon on each orbit. However, until now, it has not been possible to derive absolute measurements of lunar irradiance using CERES because the Moon's disk fills only 10% of the telescope field of view. This work presents a method of integrating CERES raster-scan data in order to obtain a measurement of the average scattered solar and emitted thermal radiance from the entire lunar disk. The technique results in excellent agreement between CERES instruments on different satellites as to lunar albedo and emitted thermal flux. The average broadband Moon albedo is measured by CERES at a value of 0.1362 (+/-2-3%) when normalized to a static lunar phase angle of 7 degrees using the U.S. Geological Survey lunar irradiance Robotic Lunar Observatory model. The method for the first time also yields very accurate measurements of the thermal irradiance emitted from the Moon. These suggest an average long-wave flux of 977 Wm(-2) (+/-2-3% at 7 degrees phase), implying an approximate mean surface temperature of around 92 degrees C. Statistical analysis on available data suggests that a CERES instrument performing monthly lunar measurements could utilize the Moon as a stability target and reduce calibration drifts to 0.3% per decade or less within an instrument's lifetime. Given the success of the technique, a solar calibration system is proposed that will allow precise tracking of an ERB instrument's optical degradation using the Sun. PMID:18806861

  19. Evaluation of HCMM satellite data for estuarine tidal circulation patterns and thermal inertia soil moisture measurements. [Delaware Bay, Cooper River, and the Potomac River estuaries; Luverne, Minnesota, soil moisture, and water temperature of Lake Anna, Virginia

    NASA Technical Reports Server (NTRS)

    Wiesnet, D. R.; Mcginnis, D. F., Jr. (Principal Investigator); Matson, M.; Pritchard, J. A.

    1981-01-01

    Digital thermal maps of the Cooper River (SC) and the Potomac River estuaries were prepared from heat capacity mapping radiometer (HCMR) tapes. Tidal phases were correctly interpreted and verified. Synoptic surface circulation patterns were charted by location thermal fronts and water mass boundaries within the estuaries. Thermal anomalies were detected adjacent of a conventional power plant on the Potomac. Under optimum conditions, estuaries as small as the Cooper River can be monitored for generalized thermal/tidal circulation patterns by the HCMM-type IR sensors. The HCMM thermal inertia approach to estimating soil moisture at the Luverne (MN) test site was found to be unsatisfactory as a NESS operational satellite technique because of cloud cover interference. Thermal-IR data show similar structure of the Baltimore and Washington heat islands when compared to NOAA AVHRR thermal-IR data. Thermal anomalies from the warm water discharge water of a nuclear power plant were mapped in Lake Anna, Virginia.

  20. The influence of thermal inertia on Mars' seasonal pressure variation and the effect of the weather component

    NASA Technical Reports Server (NTRS)

    Wood, S. E.; Paige, D. A.

    1993-01-01

    Using a Leighton-Murray type diurnal and seasonal Mars thermal model, we found that it is possible to reproduce the seasonal variation in daily-averaged pressures (approximately 680-890 Pa) measured by Viking Lander 1 (VL1), during years without global dust storms, with a standard deviation of less than 5 Pa. In this simple model, surface CO2, frost condensation, and sublimation rates at each latitude are determined by the net effects of radiation, latent heat, and heat conduction in subsurface soil layers. An inherent assumption of our model is that the seasonal pressure variation is due entirely to the exchange of mass between the atmosphere and polar caps. However, the results of recent Mars GCM modeling have made it clear that there is a significant dynamical contribution to the seasonal pressure variation. This 'weather' component is primarily due to large-scale changes in atmospheric circulation, and its magnitude depends somewhat on the dust content of the atmosphere. The overall form of the theoretical weather component at the location of VL1, as calculated by the AMES GCM, remains the same over the typical range of Mars dust opacities.

  1. A two-layer canopy model with thermal inertia for an improved snowpack energy balance below needleleaf forest (model SNOWPACK, version 3.2.1, revision 741)

    NASA Astrophysics Data System (ADS)

    Gouttevin, I.; Lehning, M.; Jonas, T.; Gustafsson, D.; Molder, M.

    2015-08-01

    A new, two-layer canopy module with thermal inertia as part of the detailed snow model SNOWPACK (version 3.2.1) is presented and evaluated. As a by-product of these new developments, an exhaustive description of the canopy module of the SNOWPACK model is provided, thereby filling a gap in the existing literature. In its current form, the two-layer canopy module is suited for evergreen needleleaf forest, with or without snow cover. It is designed to reproduce the difference in thermal response between leafy and woody canopy elements, and their impact on the underlying snowpack or ground surface energy balance. Given the number of processes resolved, the SNOWPACK model with its enhanced canopy module constitutes a sophisticated physics-based modeling chain of the continuum going from atmosphere to soil through the canopy and snow. Comparisons of modeled sub-canopy thermal radiation to stand-scale observations at an Alpine site (Alptal, Switzerland) demonstrate improvements induced by the new canopy module. Both thermal heat mass and the two-layer canopy formulation contribute to reduce the daily amplitude of the modeled canopy temperature signal, in agreement with observations. Particularly striking is the attenuation of the nighttime drop in canopy temperature, which was a key model bias. We specifically show that a single-layered canopy model is unable to produce this limited temperature drop correctly. The impact of the new parameterizations on the modeled dynamics of the sub-canopy snowpack is analyzed. The new canopy module yields consistent results but the frequent occurrence of mixed-precipitation events at Alptal prevents a conclusive assessment of model performance against snow data. The new model is also successfully tested without specific tuning against measured tree temperature and biomass heat-storage fluxes at the boreal site of Norunda (Sweden). This provides an independent assessment of its physical consistency and stresses the robustness and

  2. First Retrieval of Surface Lambert Albedos From Mars Reconnaissance Orbiter CRISM Data

    NASA Astrophysics Data System (ADS)

    McGuire, P. C.; Arvidson, R. E.; Murchie, S. L.; Wolff, M. J.; Smith, M. D.; Martin, T. Z.; Milliken, R. E.; Mustard, J. F.; Pelkey, S. M.; Lichtenberg, K. A.; Cavender, P. J.; Humm, D. C.; Titus, T. N.; Malaret, E. R.

    2006-12-01

    at 2.5 μm, 3) a physical thermal model (PTM) based upon maps of thermal inertia from TES and coarse-resolution surface slopes (SS) from MOLA, and 4) a photoclinometric extension to the PTM that uses CRISM albedos at 0.41 μm to compute the SS at CRISM spatial resolution. For the thermal correction, we expect that each of these 4 different techniques will be valuable for some fraction of the observations.

  3. Inertia and Decision Making.

    PubMed

    Alós-Ferrer, Carlos; Hügelschäfer, Sabine; Li, Jiahui

    2016-01-01

    Decision inertia is the tendency to repeat previous choices independently of the outcome, which can give rise to perseveration in suboptimal choices. We investigate this tendency in probability-updating tasks. Study 1 shows that, whenever decision inertia conflicts with normatively optimal behavior (Bayesian updating), error rates are larger and decisions are slower. This is consistent with a dual-process view of decision inertia as an automatic process conflicting with a more rational, controlled one. We find evidence of decision inertia in both required and autonomous decisions, but the effect of inertia is more clear in the latter. Study 2 considers more complex decision situations where further conflict arises due to reinforcement processes. We find the same effects of decision inertia when reinforcement is aligned with Bayesian updating, but if the two latter processes conflict, the effects are limited to autonomous choices. Additionally, both studies show that the tendency to rely on decision inertia is positively associated with preference for consistency. PMID:26909061

  4. Inertia and Decision Making

    PubMed Central

    Alós-Ferrer, Carlos; Hügelschäfer, Sabine; Li, Jiahui

    2016-01-01

    Decision inertia is the tendency to repeat previous choices independently of the outcome, which can give rise to perseveration in suboptimal choices. We investigate this tendency in probability-updating tasks. Study 1 shows that, whenever decision inertia conflicts with normatively optimal behavior (Bayesian updating), error rates are larger and decisions are slower. This is consistent with a dual-process view of decision inertia as an automatic process conflicting with a more rational, controlled one. We find evidence of decision inertia in both required and autonomous decisions, but the effect of inertia is more clear in the latter. Study 2 considers more complex decision situations where further conflict arises due to reinforcement processes. We find the same effects of decision inertia when reinforcement is aligned with Bayesian updating, but if the two latter processes conflict, the effects are limited to autonomous choices. Additionally, both studies show that the tendency to rely on decision inertia is positively associated with preference for consistency. PMID:26909061

  5. Characterization of the High-Albedo NEA 3691 Bede

    NASA Technical Reports Server (NTRS)

    Wooden, Diane H.; Lederer, Susan M.; Jehin, Emmanuel; Rozitis, Benjamin; Jefferson, Jeffrey D.; Nelson, Tyler W.; Dotson, Jessie L.; Ryan, Erin L.; Howell, Ellen S.; Fernandez, Yanga R.; Lovell, Amy J.; Woodward, Charles E.; Harker, David E.

    2016-01-01

    Characterization of NEAs provides important inputs to models for atmospheric entry, risk assessment and mitigation. Diameter is a key parameter because diameter translates to kinetic energy in atmospheric entry. Diameters can be derived from the absolute magnitude, H(PA=0deg), and from thermal modeling of observed IR fluxes. For both methods, the albedo (pv) is important - high pv surfaces have cooler temperatures, larger diameters for a given Hmag, and shallower phase curves (larger slope parameter G). Thermal model parameters are coupled, however, so that a higher thermal inertia also results in a cooler surface temperature. Multiple parameters contribute to constraining the diameter. Observations made at multiple observing geometries can contribute to understanding the relationships between and potentially breaking some of the degeneracies between parameters. We present data and analyses on NEA 3691 Bede with the aim of best constraining the diameter and pv from a combination of thermal modeling and light curve analyses. We employ our UKIRT+Michelle mid-IR photometric observations of 3691 Bede's thermal emission at 2 phase angles (27&43 deg 2015-03-19 & 04-13), in addition to WISE data (33deg 2010-05-27, Mainzer+2011). Observing geometries differ by solar phase angles and by moderate changes in heliocentric distance (e.g., further distances produce somewhat cooler surface temperatures). With the NEATM model and for a constant IR beaming parameter (eta=constant), there is a family of solutions for (diameter, pv, G, eta) where G is the slope parameter from the H-G Relation. NEATM models employing Pravec+2012's choice of G=0.43, produce D=1.8 km and pv˜0.4, given that G=0.43 is assumed from studies of main belt asteroids (Warner+2009). We present an analysis of the light curve of 3691 Bede to constrain G from observations. We also investigate fitting thermophysical models (TPM, Rozitis+11) to constrain the coupled parameters of thermal inertia (Gamma) and surface

  6. Comparison of Observed Surface Temperatures of 4 Vesta to the KRC Thermal Model

    NASA Technical Reports Server (NTRS)

    Titus, T. N.; Becker, K. J.; Anderson, J. A.; Capria, M. T.; Tosi, F.; DeSanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.-P.; McCord, T. B.; Li, J.-Y.; Russell, C. T.; Ryamond, C. A.; Mittlefehldt, D.; Toplis, M.; Forni, O.; Sykes, M. V.

    2012-01-01

    In this work, we will compare ob-served temperatures of the surface of Vesta using data acquired by the Dawn [1] Visible and Infrared Map-ping Spectrometer (VIR-MS) [2] during the approach phase to model results from the KRC thermal model. High thermal inertia materials, such as bedrock, resist changes in temperature while temperatures of low thermal inertia material, such as dust, respond quickly to changes in solar insolation. The surface of Vesta is expected to have low to medium thermal inertia values, with the most commonly used value being extremely low at 15 TIU [4]. There are several parameters which affect observed temperatures in addition to thermal inertia: bond albedo, slope, and surface roughness. In addition to these parameters, real surfaces are rarely uniform monoliths that can be described by a single thermal inertia value. Real surfaces are often vertically layered or are mixtures of dust and rock. For Vesta's surface, with temperature extremes ranging from 50 K to 275 K and no atmosphere, even a uniform monolithic surface may have non-uniform thermal inertia due to temperature dependent thermal conductivity.

  7. The joint influence of albedo and insulation on roof performance: An observational study

    SciTech Connect

    Ramamurthy, P.; Sun, T.; Rule, K.; Bou-Zeid, E.

    2015-02-23

    We focus on understanding the temperature and heat flux fields in building roofs, and how they are modulated by the interacting influences of albedo and insulation at annual, seasonal and diurnal scales. High precision heat flux plates and thermocouples were installed over multiple rooftops of varying insulation thickness and albedo in the Northeastern United States to monitor the temperature and the heat flux into and out of the roof structures for a whole year. This analysis shows that while membrane reflectivity (albedo) plays a dominant role in reducing the heat conducted inward through the roof structures during the warmer months, insulation thickness becomes the main roof attribute in preventing heat loss from the buildings during colder months. On a diurnal scale, the thermal state of the white roof structures fluctuated little compared to black roof structures; membrane temperature over white roofs ranged between 10 °C and 45 °C during summer months compared to black membranes that ranged between 10 °C and 80 °C. Insulation thickness, apart from reducing the heat conducted through the roof structure, also delayed the transfer of heat, owing to the thermal inertia of the insulation layer. Furthermore, this has important implications for determining the peak heating and cooling times.

  8. The joint influence of albedo and insulation on roof performance: An observational study

    DOE PAGESBeta

    Ramamurthy, P.; Sun, T.; Rule, K.; Bou-Zeid, E.

    2015-02-23

    We focus on understanding the temperature and heat flux fields in building roofs, and how they are modulated by the interacting influences of albedo and insulation at annual, seasonal and diurnal scales. High precision heat flux plates and thermocouples were installed over multiple rooftops of varying insulation thickness and albedo in the Northeastern United States to monitor the temperature and the heat flux into and out of the roof structures for a whole year. This analysis shows that while membrane reflectivity (albedo) plays a dominant role in reducing the heat conducted inward through the roof structures during the warmer months,more » insulation thickness becomes the main roof attribute in preventing heat loss from the buildings during colder months. On a diurnal scale, the thermal state of the white roof structures fluctuated little compared to black roof structures; membrane temperature over white roofs ranged between 10 °C and 45 °C during summer months compared to black membranes that ranged between 10 °C and 80 °C. Insulation thickness, apart from reducing the heat conducted through the roof structure, also delayed the transfer of heat, owing to the thermal inertia of the insulation layer. Furthermore, this has important implications for determining the peak heating and cooling times.« less

  9. Galileo PPR observations of Europa: Hotspot detection limits and surface thermal properties

    NASA Astrophysics Data System (ADS)

    Rathbun, Julie A.; Rodriguez, Nathaniel J.; Spencer, John R.

    2010-12-01

    The Galileo photopolarimeter-radiometer (PPR) made over 100 observations of Europa's surface temperature. We have used these data to constrain a diurnal thermal model and, thus, map the thermal inertia and bolometric albedo over 20% of the surface. We find an increased thermal inertia at mid-latitudes that is widespread in longitude and does not appear to correlate with geology, albedo, or other observables. Our derived thermophysical properties can be used to predict volatile stability across the surface over the course of a day and in planning of infrared instruments on future missions. Furthermore, while observations in the thermal infrared can and have been used to find endogenic activity, no such activity was detected at Europa. We have calculated the detection limits of these PPR observations and find that 100 km 2 hotspots with temperatures of 116-1200 K could exist undetected on the surface, depending on the location.

  10. Thermal studies of Martian channels and valleys using Termoskan data: New results

    NASA Technical Reports Server (NTRS)

    Betts, B. H.; Murray, B. C.

    1993-01-01

    The Termoskan instrument onboard the Phobos '88 spacecraft acquired the highest-spatial-resolution thermal data ever obtained for Mars. Included in the thermal images are 2 km/pixel midday observations of several major channel and valley systems, including significant portions of Shalbatana Vallis, Ravi Vallis, Al-Qahira Vallis, Ma'adim Vallis, the channel connecting Valles Marineris with Hydraotes Chaos, and channel material in Eos Chasma. Termoskan also observed small portions of the southern beginnings of Simud, Tiu, and Ares Valles and some channel material in Gangis Chasma. Simultaneous broad band visible data were obtained for all but Ma'adim Vallis. We find that most of the channels and valleys have higher inertias than their surroundings, consistent with Viking IRTM-based thermal studies of Martian channels. We see for the first time that thermal inertia boundaries closely match all flat channel floor boundaries. Combining Termoskan thermal data, relative observations from Termoskan visible channel data, Viking absolute bolometric albedos, and a thermal model of the Mars surface, we have derived lower bounds on channel thermal inertias. Lower bounds on typical channel thermal inertias range from 8.4 to 12.5 (10(exp -3) cal cm(exp -2) s(exp -1/2)K(exp -1)) (352 to 523 in SI units). Lower bounds on inertia differences with the surrounding heavily cratered plains range from 1.1 to 3.5 (46 to 147 in SI units). Atmospheric and geometric effects are not sufficient to cause the inertia enhancements. We agree with previous researchers that localized, dark, high inertia areas within channels are likely eolian in nature. However, the Temloskan data show that eolian deposits do not fill the channels, nor are they responsible for the overall thermal inertia enhancement. Thermal homogeneity and strong correlation of thermal boundaries with the channel floor boundaries lead us to favor noneolian overall explanations.

  11. Physical properties (particle size, rock abundance) from thermal infrared remote observations: Implications for Mars landing sites

    NASA Technical Reports Server (NTRS)

    Christensen, P. R.; Edgett, Kenneth S.

    1994-01-01

    Critical to the assessment of potential sites for the 1997 Pathfinder landing is estimation of general physical properties of the martian surface. Surface properties have been studied using a variety of spacecraft and earth-based remote sensing observations, plus in situ studies at the Viking lander sites. Because of their value in identifying landing hazards and defining scientific objectives, we focus this discussion on thermal inertia and rock abundance derived from middle-infrared (6 to 30 microns) observations. Used in conjunction with other datasets, particularly albedo and Viking orbiter images, thermal inertia and rock abundance provide clues about the properties of potential Mars landing sites.

  12. Calculation of albedos for neutrons and photons

    NASA Astrophysics Data System (ADS)

    Brockhoff, Ronald Carl

    2003-07-01

    The albedo concept is used to describe radiation that appears to be reflected from a surface, although in reality this reflected radiation is comprised of radiation that has entered the medium, and is subsequently scattered back through the surface. The albedo often offers a computationally simple alternative to estimate doses from radiation reflected from surfaces surrounding a streaming region. However, albedo data available prior to this study, are limited to relatively few source energies and reflecting media, and are based on obsolete and incomplete cross sections and response functions. The Monte Carlo code MCNP is applied in this study to calculate the differential photon and neutron dose albedos, along with the differential secondary-photon dose albedo, based on modern response functions and cross section data. Differential photon dose albedo data were calculated for source energies ranging from 0.1 to 10 MeV incident on slabs of concrete, iron, lead, and water. Differential neutron dose albedo data, and the associated differential secondary-photon dose albedo data, were calculated for source energy bands ranging from 0.1 to 10 MeV, and for thermal, Californium, and 14 MeV source spectra, incident on the same four reflecting media. The results indicate that (1) the approximation of the differential photon dose albedo proposed by Chilton and Huddleston usually deviates from the raw albedo data by less than 10% for source energies between 0.1 and 10.0 MeV, (2) the new 24-parameter approximation of the differential neutron dose albedo deviates from the raw albedo data by less than 10% for source energy bands between 0.1 and 10 MeV, and (3) the five-parameter approximation of the secondary-photon dose albedo deviates from the raw albedo data by less than 25% for source energies between 0.1 and 10 MeV. The differential dose albedo approximations obtained in this study are used to solve several example radiation transport problems, where the dose from reflected

  13. Surfaces of Europa, Ganymede, and Callisto: an investigation using Voyager IRIS thermal infrared spectra

    SciTech Connect

    Spencer, J.R.

    1987-01-01

    In 1979, the IRIS infrared spectrometers on the two Voyager spacecraft obtained over 1000 disk-resolved thermal emission spectra of Europa, Ganymede, and Callisto, Jupiter's three large icy satellites. This dissertation describes the first detailed analysis of this data set. Ganymede and Callisto subsolar temperatures are 10 and 5/sup 0/K, respectively, below equilibrium values. Equatorial nighttime temperatures are between 100 and 75/sup 0/K, Callisto and Europa being colder than Ganymede. The diurnal temperature profiles can be matched by 2-layer surfaces that are also consistent with the eclipse cooling observed from earth, though previous eclipse models underestimated thermal inertias by about 50%. Substrate thermal inertias in the 2-layer models are a factor of several lower than for solid ice. These are cold spots on Ganymede and Callisto that are not high-albedo regions, which may indicate large thermal inertia anomalies.

  14. Shaking Off Inertia.

    ERIC Educational Resources Information Center

    Campbell, David N.

    1991-01-01

    According to Tom Peters's book "Thriving on Chaos," change must become the norm, not cause for alarm. What Peters saw in the business world predominates in schools--the same inertia, fear of innovation, and rejection of technology. Schools can profit by taking Peters's advice about using research and changing antiquated teaching practices. (MLH)

  15. Radiation Dose from Lunar Neutron Albedo

    NASA Technical Reports Server (NTRS)

    Adams, J. H., Jr.; Bhattacharya, M.; Lin, Zi-Wei; Pendleton, G.

    2006-01-01

    The lunar neutron albedo from thermal energies to 8 MeV was measured on the Lunar Prospector Mission in 1998-1999. Using GEANT4 we have calculated the neutron albedo due to cosmic ray bombardment of the moon and found a good-agreement with the measured fast neutron spectra. We then calculated the total effective dose from neutron albedo of all energies, and made comparisons with the effective dose contributions from both galactic cosmic rays and solar particle events to be expected on the lunar surface.

  16. Phase-Angle Dependence of Determinations of Diameter, Albedo, and Taxonomy: A case study of NEO 3691 Bede

    NASA Astrophysics Data System (ADS)

    Wooden, D. H.; Lederer, S. M.; Jehin, E.; Howell, E. S.; Fernandez, Y. R.; Harker, D. E.; Ryan, E. L.; Lovell, A. J.; Woodward, C. E.; Benner, L.

    2015-12-01

    Parameters important for NEO risk assessment and mitigation include Near-Earth Object diameter and taxonomic classification, which translates to surface composition. Diameters of NEOs are derived from the thermal fluxes measured by WISE, NEOWISE, Spitzer Warm Mission and ground-based telescopes including the IRTF and UKIRT. Diameter and its coupled parameters Albedo and IR beaming parameter (a proxy for thermal inertia and/or surface roughness) are dependent upon the phase angle, which is the Sun-target-observer angle. Orbit geometries of NEOs, however, typically provide for observations at phase angles > 20 degrees. At higher phase angles, the observed thermal emission is sampling both the day and night sides of the NEO. We compare thermal models for NEOs that exclude (NEATM) and include (NESTM) night-side emission. We present a case study of NEO 3691 Bede, which is a higher albedo object, X (Ec) or Cgh taxonomy, to highlight the range of H magnitudes for this object (depending on the albedo and phase function slope parameter G), and to examine at different phase angles the taxonomy and thermal model fits for this NEO. Observations of 3691 Bede include our observations with IRTF+SpeX and with the 10μm UKIRT+Michelle instrument, as well as WISE and Spitzer Warm mission data. By examining 3691 Bede as a case study, we highlight the interplay between the derivation of basic physical parameters and observing geometry, and we discuss the uncertainties in H magnitude, taxonomy assignment amongst the X-class (P, M, E), and diameter determinations. Systematic dependencies in the derivation of basic characterization parameters of H-magnitude, diameter, albedo and taxonomy with observing geometry are important to understand. These basic characterization parameters affect the statistical assessments of the NEO population, which in turn, affects the assignment of statistically-assessed basic parameters to discovered but yet-to-be-fully-characterized NEOs.

  17. Structure of the Saint Francois Mountains and surrounding lead belt, S.E. Missouri: Inference from thermal IR and other data sets

    NASA Technical Reports Server (NTRS)

    Arvidson, R. E. (Principal Investigator)

    1982-01-01

    Progress in the preparation of manuscripts on the discovery of a Precambrian rift running NW-SE through Missouri as seen in free air and Bouguer gravity anomalies and in HCMM data, and on digital image processing of potential field and topographic data on the rift is reported. Copies of the papers are attached. Contrast-enhanced HCMM images that have been transformed to Mercator projections are presented. Shaded relief map overlays of thermal and apparent thermal inertia images used as part of a masers thesis examining correlations between HCMM data products, linears, and geologic units are presented. Progress in examination of the difference in information content of daytime infrared, night time infrared, albedo, and thermal inertia images and their application to he identification of linears not directly controlled by topography is reported. Thermal infrared and albedo data were coded as hue, saturation and brightness values to generate a color display, which is included.

  18. Earth's Reflection: Albedo

    ERIC Educational Resources Information Center

    Gillette, Brandon; Hamilton, Cheri

    2011-01-01

    When viewing objects of different colors, you might notice that some appear brighter than others. This is because light is reflected differently from various surfaces, depending on their physical properties. The word "albedo" is used to describe how reflective a surface is. The Earth-atmosphere has a combined albedo of about 30%, a number that is…

  19. Albedos. Final report

    SciTech Connect

    Hansen, F.V.

    1993-07-01

    The albedo of the earth's surface varies dramatically from values of about 3 to 4 percent for calm bodies of water up to about 55 percent for gypsum sands. This rather broad range of reflected incoming solar radiation presents difficulties when attempting to define an average albedo for terrain over a large region from locally determined values. The patchwork, or checkerboard, appearance of the earth's surface as viewed from above is the result of various human activities, such as agriculture, the proliferation of urban sprawl, and road building. Each of these variable appearing surfaces will have individual albedos, rendering any attempt to determine an a real albedo almost an impossibility on the mesoscale. However, a vast data base exists for microscale applications for individual acreages, for example. A compilation of these data is presented.... Albedo, Solar radiation, Crops, Urban areas, Land uses.

  20. Observations of Surfzone Albedo

    NASA Astrophysics Data System (ADS)

    Sinnett, G.; Feddersen, F.

    2014-12-01

    The surfzone environment (where waves break) contains several unique and previously unconsidered processes that affect the heat budget. Entering short-wave radiation is a dominant term in both shelf and surfzone heat budgets. In contrast to the shelf, however, depth limited wave breaking in the surfzone generates spray, whitewater and suspended sediments, elevating the surface albedo (ratio of reflected to incident short-wave radiation). Elevated albedo reduces the level of solar short-wave radiation entering the water, potentially resulting in less heating. Additionally, surfzone water quality is often impacted by fecal bacteria contamination. As bacteria mortality is related to short-wave solar radiation, elevated surfzone albedo could reduce pathogen mortality, impacting human health. Albedo in the open ocean has been frequently studied and parameterizations often consider solar zenith angle, wind speed and ocean chlorophyll concentration, producing albedo values typically near 0.06. However, surfzone albedo observations have been extremely sparse, yet show depth limited wave breaking may increase the albedo by nearly a factor of 10 up to 0.5. Here, we present findings from a field study at the Scripps Institution of Oceanography pier to observe the affect of waves on surfzone albedo. Concurrent measurements were taken with a four-way radiometer (to measure both downwelling and upwelling short-wave and long wave radiation) mounted above the surfzone. A co-located GoPro camera was used to relate visual aspects of the surfzone to measured reflectance, and wave height and period were observed with a bottom mounted pressure sensor in 5 m water depth just outside the surfzone. Wind speed and direction were observed on the pier 10 m above the water surface. Here, we will examine the surfzone albedo dependence on surfzone parameters, such as wave height.

  1. Greenland Glacier Albedo Variability

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The program for Arctic Regional Climate Assessment (PARCA) is a NASA-funded project with the prime goal of addressing the mass balance of the Greenland ice sheet. Since the formal initiation of the program in 1995, there has been a significant improvement in the estimates of the mass balance of the ice sheet. Results from this program reveal that the high-elevation regions of the ice sheet are approximately in balance, but the margins are thinning. Laser surveys reveal significant thinning along 70 percent of the ice sheet periphery below 2000 m elevations, and in at least one outlet glacier, Kangerdlugssuaq in southeast Greenland, thinning has been as much as 10 m/yr. This study examines the albedo variability in four outlet glaciers to help separate out the relative contributions of surface melting versus ice dynamics to the recent mass balance changes. Analysis of AVHRR Polar Pathfinder albedo shows that at the Petermann and Jakobshavn glaciers, there has been a negative trend in albedo at the glacier terminus from 1981 to 2000, whereas the Stor+strommen and Kangerdlugssuaq glaciers show slightly positive trends in albedo. These findings are consistent with recent observations of melt extent from passive microwave data which show more melt on the western side of Greenland and slightly less on the eastern side. Significance of albedo trends will depend on where and when the albedo changes occur. Since the majority of surface melt occurs in the shallow sloping western margin of the ice sheet where the shortwave radiation dominates the energy balance in summer (e.g. Jakobshavn region) this region will be more sensitive to changes in albedo than in regions where this is not the case. Near the Jakobshavn glacier, even larger changes in albedo have been observed, with decreases as much as 20 percent per decade.

  2. Free piston inertia compressor

    DOEpatents

    Richards, William D. C.; Bilodeau, Denis; Marusak, Thomas; Dutram, Jr., Leonard; Brady, Joseph

    1981-01-01

    A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to excape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

  3. Free piston inertia compressor

    DOEpatents

    Richards, W.D.C.; Bilodeau, D.; Marusak, T.; Dutram, L. Jr.; Brady, J.

    A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to escape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

  4. Physical Characteristics of Near-Earth Asteroids from Thermal Infrared Spectrophotometry

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Davies, John K.

    1999-12-01

    Thermal infrared spectrophotometric observations of the near-Earth asteroids 433 Eros, 1980 Tezcatlipoca, and 3671 Dionysus are presented and their implications for the physical characteristics of the objects discussed. Sizes and albedos are derived on the basis of published thermal models and comparison of the infrared data with optical observations. The results for 433 Eros are in very good agreement with radar and other earlier findings and demonstrate the accuracy achievable with one of the thermal models used. The new data, together with earlier results from the literature, suggest the surface thermal inertia of 433 Eros is no larger than three times that of the Moon. The derived effective diameter and optical albedo of 1980 Tezcatlipoca (around lightcurve maximum) are D=6.7±1.0 km and pV=0.15±0.05, and for 3671 Dionysus D=1.0±0.2 km and pV=0.40±0.15. These diameters are significantly different from previous estimates. The thermal continua of Tezcatlipoca and Dionysus are indicative of high surface thermal inertias. A near-infrared spectrum of Dionysus, coupled with the high albedo, suggests an M or E classification. Such taxonomic types are relatively rare amongst near-Earth asteroids.

  5. Simulation and Interpretation of the BIBI Ratio CB (.), as a Function of Thermal Parameters of the Low Inertia Polyethylene Wall of Greenhouses

    NASA Astrophysics Data System (ADS)

    Bendimerad, S.; Mahdjoub, T.; Bibi-Triki, N.; Bessenouci, M. Z.; Draoui, B.; Bechar, H.

    The conventional agricultural tunnel greenhouse is highly widespread in Mediterranean countries, despite the shortcomings it presents, specifically the overheating during the day and the intense cooling at night. This can sometimes lead to an internal thermal inversion. The chapel-shaped glass greenhouse is relatively more efficient, but its evolution remains slow because of its investment cost and amortization. The thermal behavior of a greenhouse has often been studied, mainly during the night. In order to contribute to a better climatic management of the greenhouse, we proposed to develop a thermal analysis model. In this work, a ratio called BIBI was developed to characterize the covering material. This thermal evolution state depends on the degree of air-tightness of this covering material and its physical characteristics. It has to be transparent to solar rays, and must as well absorb and reflect infrared rays emitted by the soil. This leads to trapped solar rays, called the "greenhouse effect". In this paper we propose the modeling and analysis of the thermal behavior of the polyethylene (PE) wall of the experimental tunnel greenhouse.

  6. "TNOs are Cool": A survey of the trans-Neptunian region. IX. Thermal properties of Kuiper belt objects and Centaurs from combined Herschel and Spitzer observations

    NASA Astrophysics Data System (ADS)

    Lellouch, E.; Santos-Sanz, P.; Lacerda, P.; Mommert, M.; Duffard, R.; Ortiz, J. L.; Müller, T. G.; Fornasier, S.; Stansberry, J.; Kiss, Cs.; Vilenius, E.; Mueller, M.; Peixinho, N.; Moreno, R.; Groussin, O.; Delsanti, A.; Harris, A. W.

    2013-09-01

    Aims: The goal of this work is to characterize the ensemble thermal properties of the Centaurs / trans-Neptunian population. Methods: Thermal flux measurements obtained with Herschel/PACS and Spitzer/MIPS provide size, albedo, and beaming factors for 85 objects (13 of which are presented here for the first time) by means of standard radiometric techniques. The measured beaming factors are influenced by the combination of surface roughness and thermal inertia effects. They are interpreted within a thermophysical model to constrain, in a statistical sense, the thermal inertia in the population and to study its dependence on several parameters. We use in particular a Monte-Carlo modeling approach to the data whereby synthetic datasets of beaming factors are created using random distributions of spin orientation and surface roughness. Results: Beaming factors η range from values <1 to ~2.5, but high η values (>2) are lacking at low heliocentric distances (rh < 30 AU). Beaming factors lower than 1 occur frequently (39% of the objects), indicating that surface roughness effects are important. We determine a mean thermal inertia for Centaurs/ TNO of Γ = (2.5 ± 0.5) J m-2 s-1/2 K-1, with evidence of a trend toward decreasing Γ with increasing heliocentric (by a factor ~2.5 from 8-25 AU to 41-53 AU). These thermal inertias are 2-3 orders of magnitude lower than expected for compact ices, and generally lower than on Saturn's satellites or in the Pluto/Charon system. Most high-albedo objects are found to have unusually low thermal inertias. Our results suggest highly porous surfaces, in which the heat transfer is affected by radiative conductivity within pores and increases with depth in the subsurface. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Table 3 is available in electronic form at http://www.aanda.org

  7. Incorporating inertia into multiagent systems

    NASA Astrophysics Data System (ADS)

    Man, W. C.; Chau, H. F.

    2006-03-01

    We consider a model that demonstrates the crucial role of inertia and stickiness in multiagent systems, based on the minority game. The inertia of an agent is introduced into the game model by allowing agents to apply hypothesis testing when choosing their best strategies, thereby reducing their reactivity toward changes in the environment. We find by extensive numerical simulations that our game shows a remarkable improvement of global cooperation throughout the whole phase space. In other words, the maladaptation behavior due to over-reaction of agents is removed. These agents are also shown to be advantageous over the standard ones, which are sometimes too sensitive to attain a fair success rate. We also calculate analytically the minimum amount of inertia needed to achieve the above improvement. Our calculation is consistent with the numerical simulation results. Finally, we review some related works in the field that show similar behaviors and compare them to our work.

  8. ALBEDOS OF SMALL HILDA GROUP ASTEROIDS AS REVEALED BY SPITZER

    SciTech Connect

    Ryan, Erin Lee; Woodward, Charles E. E-mail: chelsea@astro.umn.edu

    2011-06-15

    We present thermal 24 {mu}m observations from the Spitzer Space Telescope of 62 Hilda asteroid group members with diameters ranging from 3 to 12 km. Measurements of the thermal emission, when combined with reported absolute magnitudes, allow us to constrain the albedo and diameter of each object. From our Spitzer sample, we find the mean geometric albedo, p{sub V} = 0.07 {+-} 0.05, for small (D < 10 km) Hilda group asteroids. This Spitzer-derived value of p{sub V} is greater than and spans a larger range in albedo space than the mean albedo of large (D {approx}> 10 km) Hilda group asteroids which is p{sub V} = 0.04 {+-} 0.01. Though this difference may be attributed to space weathering, the small Hilda group population reportedly displays greater taxonomic range from C-, D-, and X-type whose albedo distributions are commensurate with the range of determined albedos. We discuss the derived Hilda size-frequency distribution, color-color space, and geometric albedo for our survey sample in the context of the expected migration induced 'seeding' of the Hilda asteroid group with outer solar system proto-planetesimals as outlined in the 'Nice' formalism.

  9. Neutron star moments of inertia

    NASA Technical Reports Server (NTRS)

    Ravenhall, D. G.; Pethick, C. J.

    1994-01-01

    An approximation for the moment of inertia of a neutron star in terms of only its mass and radius is presented, and insight into it is obtained by examining the behavior of the relativistic structural equations. The approximation is accurate to approximately 10% for a variety of nuclear equations of state, for all except very low mass stars. It is combined with information about the neutron-star crust to obtain a simple expression (again in terms only of mass and radius) for the fractional moment of inertia of the crust.

  10. Radiative transfer in dusty nebulae. III - The effects of dust albedo

    NASA Technical Reports Server (NTRS)

    Petrosian, V.; Dana, R. A.

    1980-01-01

    The effects of an albedo of internal dust, such as ionization structure and temperature of dust grain, were studied by the quasi-diffusion method with an iterative technique for solving the radiative heat transfer equations. It was found that the generalized on-the-spot approximation solution is adequate for most astrophysical applications for a zero albedo; for a nonzero albedo, the Eddington approximation is more accurate. The albedo increases the average energy of the diffuse photons, increasing the ionization level of hydrogen and heavy elements if the Eddington approximation is applied; the dust thermal gradient is reduced so that the infrared spectrum approaches blackbody spectrum with an increasing albedo.

  11. Measuring the Moment of Inertia

    ERIC Educational Resources Information Center

    Lehmberg, George L.

    1978-01-01

    Two physics experiments are described, One, involving a laboratory cart accelerated along a level surface, examines the concept of inertial mass in translation and the other, using a solid cylinder, measures the moment of inertia of a wheel. Equations and illustrations are included. (MA)

  12. Moment of Inertia by Differentiation

    ERIC Educational Resources Information Center

    Rizcallah, Joseph A.

    2015-01-01

    The calculation of the moment of inertia of an extended body, as presented in standard introductory-level textbooks, involves the evaluation of a definite integral--an operation often not fully mastered by beginners, let alone the conceptual difficulties it presents, even to the advanced student, in understanding and setting up the integral in the…

  13. Effects of surface roughness on the VIRTIS/Rosetta thermal measurements

    NASA Astrophysics Data System (ADS)

    Leyrat, C.; Erard, S.; Capria, M.; Capaccioni, F.

    2014-07-01

    Thermal emission from planetary surfaces depends on many physical processes/parameters such as the Bond albedo, the heat capacity, the thermal inertia, the sublimation of ices at the surfaces, but also on the small-scale surface roughness. Distinguishing the effect of both thermal inertia and surface roughness on the infrared measurements is not trivial. In particular, surface roughness, that cannot be resolved within the pixels of instruments frame, can produce both shadows at small scales and mutual heating, which affect the thermal flux and the temperature estimations. The effect of roughness also varies with local incidence and emission angles, and local time, being significantly stronger closed to terminator when the local hills cast their shadows at far distances. In this poster, we present a thermo-physical model based on thermal conduction of heat over several diurnal and seasonal skin depths and show how surface roughness affects the retrieved temperature, especially, in the near-infrared domain [1--5 microns], where the VIRTIS/Rosetta instrument will observe comet CG 67/P starting in July 2014. We first compute the surface temperature of CG 67P using a simple thermo-physical model that takes into account the global shape of the nucleus. Then, we investigate (1) how the surface roughness can modify the apparent surface temperature and the thermal inertia, and (2) what are the best geometries of observation to distinguish between topographic effects and physical thermal processes.

  14. MISR Level 3 Albedo and Cloud Versioning

    Atmospheric Science Data Center

    2016-09-07

    ... 2:  CLOUD - Wind Vectors, Height Histogram Stage 1:  ALBEDO - Expansive, Restrictive and Local Albedo (except over snow and ... Stage 2 CLOUD - Height Histogram Stage 1 CLOUD - Wind Vectors Stage 1 ALBEDO - Expansive and Restrictive ...

  15. Rotational propulsion enabled by inertia.

    PubMed

    Nadal, François; Pak, On Shun; Zhu, LaiLai; Brandt, Luca; Lauga, Eric

    2014-07-01

    The fluid mechanics of small-scale locomotion has recently attracted considerable attention, due to its importance in cell motility and the design of artificial micro-swimmers for biomedical applications. Most studies on the topic consider the ideal limit of zero Reynolds number. In this paper, we investigate a simple propulsion mechanism --an up-down asymmetric dumbbell rotating about its axis of symmetry-- unable to propel in the absence of inertia in a Newtonian fluid. Inertial forces lead to continuous propulsion for all finite values of the Reynolds number. We study computationally its propulsive characteristics as well as analytically in the small-Reynolds-number limit. We also derive the optimal dumbbell geometry. The direction of propulsion enabled by inertia is opposite to that induced by viscoelasticity. PMID:25034393

  16. Space-Based Thermal Infrared Studies of Asteroids

    NASA Astrophysics Data System (ADS)

    Mainzer, A.; Usui, F.; Trilling, D. E.

    Large-area surveys operating at mid-infrared wavelengths have proven to be a valuable means of discovering and characterizing minor planets. Through the use of radiometric models, it is possible to derive physical properties such as diameters, albedos, and thermal inertia for large numbers of objects. Modern detector array technology has resulted in a significant improvement in spatial resolution and sensitivity compared with previous generations of spacebased infrared telescopes, giving rise to a commensurate increase in the number of objects that have been observed at these wavelengths. Spacebased infrared surveys of asteroids therefore offer an effective method of rapidly gathering information about the orbital and physical properties of small-body populations. The AKARI, Wide-field Infrared Survey Explorer (WISE)/ Near- Earth Object Wide-field Infrared Survey Explorer (NEOWISE), Spitzer Space Telescope, and Herschel Space Observatory missions have significantly increased the number of minor planets with well-determined diameters and albedos.

  17. Surface albedo observations at Gusev Crater and Meridiani Planum, Mars

    USGS Publications Warehouse

    Bell, J.F., III; Rice, M.S.; Johnson, J. R.; Hare, T.M.

    2008-01-01

    During the Mars Exploration Rover mission, the Pancam instrument has periodically acquired large-scale panoramic images with its broadband (739??338 nm) filter in order to estimate the Lambert bolometric albedo of the surface along each rover's traverse. In this work we present the full suite of such estimated albedo values measured to date by the Spirit and Opportunity rovers along their traverses in Gusev Crater and Meridiani Planum, respectively. We include estimated bolometric albedo values of individual surface features (e.g., outcrops, dusty plains, aeolian bed forms, wheel tracks, light-toned soils, and crater walls) as well as overall surface averages of the 43 total panoramic albedo data sets acquired to date. We also present comparisons to estimated Lambert albedo values taken from the Mars Global Surveyor Mars Orbiter Camera (MOC) along the rovers' traverses, and to the large-scale bolometric albedos of the sites from the Viking Orbiter Infrared Thermal Mapper (IRTM) and Mars Global Surveyor/Thermal Emission Spectrometer (TES). The ranges of Pancam-derived albedos at Gusev Crater (0.14 to 0.25) and in Meridiani Planum. (0.10 to 0.18) are in good agreement with IRTM, TES, and MOC orbital measurements. These data sets will be a useful tool and benchmark for future investigations of albodo variations with time, including measurements from orbital instruments like the Context Camera and High Resolution Imaging Science Experiment on Mars Reconnaissance Orbiter. Long-term, accurate albedo measurements could also be important for future efforts in climate modeling as well as for studies of active surface processes. Copyright 2008 by the American Geophysical Union.

  18. The asteroid albedo scale. II - Laboratory polarimetry of dark carbon-bearing silicates

    NASA Technical Reports Server (NTRS)

    Zellner, B.; Lebertre, T.; Day, K.

    1977-01-01

    Laboratory reflection polarimetry is presented for eight samples of artificial, poorly crystalline magnesian silicates with varying admixtures of carbon black. The polarimetric slope-albedo law saturates for geometric albedos lower than about 0.05, and good agreement with the telescopic polarization-phase curves of C-type asteroids is found for albedos as low as 0.02. Thus the conclusion from thermal radiometry is confirmed that the C objects are very dark, darker than any known carbonaceous chondrite.

  19. Ks-BAND DETECTION OF THERMAL EMISSION AND COLOR CONSTRAINTS TO CoRoT-1b: A LOW-ALBEDO PLANET WITH INEFFICIENT ATMOSPHERIC ENERGY REDISTRIBUTION AND A TEMPERATURE INVERSION

    SciTech Connect

    Rogers, Justin C.; Apai, Daniel; Lopez-Morales, Mercedes; Sing, David K.; Burrows, Adam

    2009-12-20

    We report the detection in Ks-band of the secondary eclipse of the hot Jupiter CoRoT-1b from time series photometry with the ARC 3.5 m telescope at Apache Point Observatory. The eclipse shows a depth of 0.336 +- 0.042% and is centered at phase 0.5022{sup +0.0023}{sub -0.0027}, consistent with a zero eccentricity orbit (e cos omega = 0.0035{sup +0.0036}{sub -0.0042}). We perform the first optical to near-infrared multi-band photometric analysis of an exoplanet's atmosphere and constrain the reflected and thermal emissions by combining our result with the recent 0.6, 0.71, and 2.09 mum secondary eclipse detections by Snellen et al., Gillon et al., and Alonso et al. Comparing the multi-wavelength detections to state-of-the-art radiative-convective chemical-equilibrium atmosphere models, we find the near-infrared fluxes difficult to reproduce. The closest blackbody-based and physical models provide the following atmosphere parameters: a temperature T = 2460{sup +80}{sub -160} K; a very low Bond albedo A{sub B} = 0.000{sup +0.081}{sub -0.000}; and an energy redistribution parameter P{sub n} = 0.1, indicating a small but nonzero amount of heat transfer from the day to nightside. The best physical model suggests a thermal inversion layer with an extra optical absorber of opacity kappa{sub e} = 0.05 cm{sup 2} g{sup -1}, placed near the 0.1 bar atmospheric pressure level. This inversion layer is located 10 times deeper in the atmosphere than the absorbers used in models to fit mid-infrared Spitzer detections of other irradiated hot Jupiters.

  20. Ks-Band Detection of Thermal Emission and Color Constraints to CoRoT-1b: A Low-Albedo Planet with Inefficient Atmospheric Energy Redistribution and a Temperature Inversion

    NASA Astrophysics Data System (ADS)

    Rogers, Justin C.; Apai, Dániel; López-Morales, Mercedes; Sing, David K.; Burrows, Adam

    2009-12-01

    We report the detection in Ks-band of the secondary eclipse of the hot Jupiter CoRoT-1b from time series photometry with the ARC 3.5 m telescope at Apache Point Observatory. The eclipse shows a depth of 0.336 ± 0.042% and is centered at phase 0.5022+0.0023 -0.0027, consistent with a zero eccentricity orbit (e cos ω = 0.0035+0.0036 -0.0042). We perform the first optical to near-infrared multi-band photometric analysis of an exoplanet's atmosphere and constrain the reflected and thermal emissions by combining our result with the recent 0.6, 0.71, and 2.09 μm secondary eclipse detections by Snellen et al., Gillon et al., and Alonso et al. Comparing the multi-wavelength detections to state-of-the-art radiative-convective chemical-equilibrium atmosphere models, we find the near-infrared fluxes difficult to reproduce. The closest blackbody-based and physical models provide the following atmosphere parameters: a temperature T = 2460+80 -160 K; a very low Bond albedo AB = 0.000+0.081 -0.000 and an energy redistribution parameter Pn = 0.1, indicating a small but nonzero amount of heat transfer from the day to nightside. The best physical model suggests a thermal inversion layer with an extra optical absorber of opacity κ e = 0.05 cm2 g-1, placed near the 0.1 bar atmospheric pressure level. This inversion layer is located 10 times deeper in the atmosphere than the absorbers used in models to fit mid-infrared Spitzer detections of other irradiated hot Jupiters. Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium.

  1. Alignment Tool For Inertia Welding

    NASA Technical Reports Server (NTRS)

    Snyder, Gary L.

    1991-01-01

    Compact, easy-to-use tool aligns drive bar of inertia welder over hole in stub. Ensures drive bar concentric to hole within 0.002 in. (0.051 mm.). Holds two batteries and light bulb. Electrical circuit completed, providing current to bulb when pin in contact with post. When pin centered in post hole, it does not touch post, and lamp turns off. Built for use in making repair welds on liquid-oxygen-injector posts in Space Shuttle main engine. Version having suitably modified dimensions used to facilitate alignment in other forests of post.

  2. The Ultraviolet Albedo of Ganymede

    NASA Technical Reports Server (NTRS)

    McGrath, Melissa; Hendrix, Amanda

    2013-01-01

    A large set of ultraviolet images of Ganymede have been acquired with the Hubble Space Telescope over the last 15 years. These images have been used almost exclusively to study Ganymede's stunning auroral emissions (Feldman et al. 2000; Eviatar et al. 2001; McGrath et al. 2004; Saur et al. 2011; McGrath et al. 2013), and even the most basic information about Ganymede's UV albedo has yet to be gleaned from these data. We will present a first-cut analysis of both disk-averaged and spatially-resolved UV albedos of Ganymede, with focus on the spatially-resolved Lyman-alpha albedo, which has never been considered previously for this satellite. Ganymede's visibly bright regions are known to be rich in water ice, while the visibly dark regions seem to be more carbonaceous (Carlson et al., 1996). At Lyman-alpha, these two species should also have very different albedo values.

  3. Spin dynamics with inertia in metallic ferromagnets

    NASA Astrophysics Data System (ADS)

    Kikuchi, Toru; Tatara, Gen

    2015-11-01

    The nonadiabatic contribution of environmental degrees of freedom yields an effective inertia of spin in the effective spin dynamics. In this paper, we study several aspects of the inertia of spin in metallic ferromagnets: (i) a concrete expression of the spin inertia ms: ms=ℏ Sc/(2 gsd) , where Sc is the spin polarization of conduction electrons and gsd is the s d coupling constant; (ii) a dynamical behavior of spin with inertia, discussed from the viewpoints of a spinning top and of a particle on a sphere; (iii) the behavior of spin waves and domain walls in the presence of inertia and the behavior of spin with inertia under a time-dependent magnetic field.

  4. Local thermal properties of the surface of Vesta

    NASA Astrophysics Data System (ADS)

    Capria, M. T.; Tosi, F.; Capaccioni, F.; De Sanctis, M. C.; Palomba, E.; Ammannito, E.; Carraro, F.; Fonte, S.; Titus, T. N.; Combe, J.-P.; Toplis, M.; Sunshine, J.; Fulchignoni, M.; Russel, C. T.; Raymond, C. A.

    2012-04-01

    Temperature information has been obtained from the Dawn/VIR (Visible InfraRed imaging spectrometer) spectra acquired during the Vesta campaign. When combined with a thermophysical model, these temperatures can be used to derive surface thermal properties. Thermal properties are sensitive to several physical characteristics of the surface that are not all spatially resolved. Thus, the derivation of surface temperatures and thermal inertia can lead to the characterization of surface and sub-surface properties of Vesta and the determination of regolith properties. The model we are using solves the heat conduction equation and provide the temperature as a function of thermal conductivity, albedo, emissivity, density and specific heat. The model is applied to the actual shape of Vesta: for any given location, characterized by a well-defined illumination condition and a given UTC time to compute the thermal inertia that results in model temperatures providing a best-fit to surface temperatures as retrieved by VIR. The model has been already applied to the first Vesta full-disk data to derive the global average thermal inertia of Vesta. The values obtained are typical of fine-grained, unconsolidated materials (i.e. dust) and suggest a surface in which a dust layer is wide-spread on coarser regolith. The model is now being applied on small regions of the surface of Vesta. Specific regions are selected because they are interesting for some reason or appear different from the surroundings, such as, for example, dark and bright spots and other peculiar features. Given a location, the thermophysical code is applied until the obtained temperatures are matching (best-fit techniques are used) the temperatures derived from the VIR spectra. The thermal inertia, thermal conductivity, albedo and roughness values are then assumed to be characterizing the location under analysis. The results of the model must be carefully checked and interpreted by taking into account the context (from

  5. New technique to improve the accuracy of albedo neutron dosimeter evaluations

    NASA Astrophysics Data System (ADS)

    Hankins, D. E.

    The calibration factor for albedo neutron dosimeters varies greatly depending upon the energy of the neutrons in the exposure. Calibration results obtained over an eight-year period at each Lawrence Livermore National Laboratory facility where neutron exposure may occur were reviewed. A stronger relationship than expected was found between the ratio of the readings of the 9-in. to 3-in. spheres and the percent thermal. Readings from personnel and albedo badges were reviewed. The readings were consistent with the use of a calibration factor for the albedo dosimeter which varies with changes in the ratio of the personnel and albedo dosimeter TLD readings.

  6. New technique to improve the accuracy of albedo neutron dosimeter evaluations

    SciTech Connect

    Hankins, D.E.

    1984-01-01

    The calibration factor for albedo neutron dosimeters varies greatly depending upon the energy of the neutrons in the exposure. Calibration results obtained over an eight-year period at each Lawrence Livermore National Laboratory facility where neutron exposure may occur were reviewed. A stronger relationship than expected was found between the ratio of the readings of the 9-in. to 3-in. spheres and the percent thermal. Readings from personnel and albedo badges were reviewed. The readings were consistent with the use of a calibration factor for the albedo dosimeter which varies with changes in the ratio of the personnel and albedo dosimeter TLD readings. 2 references, 6 figures. (ACR)

  7. Quantum vacuum, inertia and gravitation

    NASA Astrophysics Data System (ADS)

    Jaekel, Marc-Thierry; Lambrecht, Astrid; Reynaud, Serge

    2002-11-01

    Since the early developments of quantum theory, vacuum has been recognized to be filled with irreducible zero-point field fluctuations. The corresponding very large energy density, as predicted by quantum theory, conflicts however, with observation of gravitational phenomena on macroscopic scales, a paradox also associated with the cosmological constant problem. This vacuum catastrophe has led to the common view that vacuum fluctuations should not be taken into account as a source of inertia or gravitation. Vacuum fluctuations however, produce observable mechanical effects, like Casimir forces, which are now accurately measured and agree with theoretical predictions. Vacuum fluctuations can also be shown, within the standard framework of quantum theory, to induce effects on motion in vacuum, and to lead to a contribution of Casimir energy to inertia, in conformity with the principles of relativity. Here, we advocate that paradoxes which emerge in an acute way when confronting quantum and relativity theories should rather be considered as positive hints, as they allow to raise questions about relativity of motion in quantum vacuum amenable to experimental confrontation, and also to reconsider the role of vacuum with respect to gravitation.

  8. THE HIGH ALBEDO OF THE HOT JUPITER KEPLER-7 b

    SciTech Connect

    Demory, Brice-Olivier; Seager, Sara; Madhusudhan, Nikku; Kjeldsen, Hans; Christensen-Dalsgaard, Joergen; Gillon, Michael; Rowe, Jason F.; Borucki, William J.; Koch, David G.; Welsh, William F.; Adams, Elisabeth R.; Dupree, Andrea; McCarthy, Don; Kulesa, Craig

    2011-07-01

    Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric precision at visible wavelengths to investigate these expectations. The NASA Kepler mission provides a means to widen the sample and to assess the extent to which hot Jupiter albedos are low. We present a global analysis of Kepler-7 b based on Q0-Q4 data, published radial velocities, and asteroseismology constraints. We measure an occultation depth in the Kepler bandpass of 44 {+-} 5 ppm. If directly related to the albedo, this translates to a Kepler geometric albedo of 0.32 {+-} 0.03, the most precise value measured so far for an exoplanet. We also characterize the planetary orbital phase light curve with an amplitude of 42 {+-} 4 ppm. Using atmospheric models, we find it unlikely that the high albedo is due to a dominant thermal component and propose two solutions to explain the observed planetary flux. First, we interpret the Kepler-7 b albedo as resulting from an excess reflection over what can be explained solely by Rayleigh scattering, along with a nominal thermal component. This excess reflection might indicate the presence of a cloud or haze layer in the atmosphere, motivating new modeling and observational efforts. Alternatively, the albedo can be explained by Rayleigh scattering alone if Na and K are depleted in the atmosphere by a factor of 10-100 below solar abundances.

  9. Gross shell structure of moments of inertia

    SciTech Connect

    Deleplanque, M.A.; Frauendorf, S.; Pashkevich, V.V.; Chu, S.Y.; Unzhakova, A.

    2002-07-01

    Average yrast moments of inertia at high spins, where the pairing correlations are expected to be largely absent, were found to deviate from the rigid-body values. This indicates that shell effects contribute to the moment of inertia. We discuss the gross dependence of moments of inertia and shell energies on the neutron number in terms of the semiclassical periodic orbit theory. We show that the ground-state shell energies, nuclear deformations and deviations from rigid-body moments of inertia are all due to the same periodic orbits.

  10. Spacecraft inertia estimation via constrained least squares

    NASA Technical Reports Server (NTRS)

    Keim, Jason A.; Acikmese, Behcet A.; Shields, Joel F.

    2006-01-01

    This paper presents a new formulation for spacecraft inertia estimation from test data. Specifically, the inertia estimation problem is formulated as a constrained least squares minimization problem with explicit bounds on the inertia matrix incorporated as LMIs [linear matrix inequalities). The resulting minimization problem is a semidefinite optimization that can be solved efficiently with guaranteed convergence to the global optimum by readily available algorithms. This method is applied to data collected from a robotic testbed consisting of a freely rotating body. The results show that the constrained least squares approach produces more accurate estimates of the inertia matrix than standard unconstrained least squares estimation methods.

  11. Thermal infrared opacity of the Mars atmosphere

    SciTech Connect

    Martin, T.Z.

    1986-04-01

    An analytical technique is presented for the deriving Mars atmosphere opacity from data furnished by the IR Thermal Mapper (IRTM) instruments on the Viking landers. Each IRTM features four telescopes for viewing Mars in six spectral bands and seven spatial fields of view. The present study focuses on 20 microns measurements of the thermal inertia, 0.3-3.0 microns data for the surface albedo, and, finally, the 7, 9, and 15 microns data for the actual opacity derivations. The model takes into account the atmospheric temperature profile, scattering by dust, the surface emissivity and the variation of the surface/atmosphere temperature discontinuity. Analyses are carried out of the possible error factors and the model is used to generate opacity histories for the two Viking Lander sites. The results, when compared with other astronomical data, indicate that the method is sufficiently accurate to use opacity data to analyze the processes of storm genesis and to study local storms. 26 references.

  12. Europa's Thermal Surface From Galileo PPR

    NASA Astrophysics Data System (ADS)

    Rodriguez, Nathaniel; Rathbun, J.; Spencer, J.

    2009-01-01

    Europa, one of the four Galilean moons of Jupiter, may harbor a subsurface ocean beneath its icy crust. We use the thermal data gathered from the Galileo spacecraft's PPR instrument to search for endogenic activity. Evidence of endogenic activity would provide direct support for a subsurface-ocean. We are modeling variations in temperature over the course of a day and then fitting these models to the PPR data. The two key variables that affect surface temperature are bolometric albedo and thermal inertia. We are determining these variables for each point on the surface, which will allow us to create a global model of exogenic activity due to sunlight. This information will allow us to analyze the threshold where endogenic activity becomes great enough to be detectable in the PPR data.

  13. MAIN BELT ASTEROIDS WITH WISE/NEOWISE. I. PRELIMINARY ALBEDOS AND DIAMETERS

    SciTech Connect

    Masiero, Joseph R.; Mainzer, A. K.; Bauer, J. M.; Eisenhardt, P. R. M.; DeBaun, E.; Elsbury, D.; Gautier, T. IV; Gomillion, S.; Wilkins, A.; Cutri, R. M.; Dailey, J.; McMillan, R. S.; Spahr, T. B.; Skrutskie, M. F.; Tholen, D.; Walker, R. G.; Wright, E. L.

    2011-11-10

    We present initial results from the Wide-field Infrared Survey Explorer (WISE), a four-band all-sky thermal infrared survey that produces data well suited for measuring the physical properties of asteroids, and the NEOWISE enhancement to the WISE mission allowing for detailed study of solar system objects. Using a NEATM thermal model fitting routine, we compute diameters for over 100,000 Main Belt asteroids from their IR thermal flux, with errors better than 10%. We then incorporate literature values of visible measurements (in the form of the H absolute magnitude) to determine albedos. Using these data we investigate the albedo and diameter distributions of the Main Belt. As observed previously, we find a change in the average albedo when comparing the inner, middle, and outer portions of the Main Belt. We also confirm that the albedo distribution of each region is strongly bimodal. We observe groupings of objects with similar albedos in regions of the Main Belt associated with dynamical breakup families. Asteroid families typically show a characteristic albedo for all members, but there are notable exceptions to this. This paper is the first look at the Main Belt asteroids in the WISE data, and only represents the preliminary, observed raw size, and albedo distributions for the populations considered. These distributions are subject to survey biases inherent to the NEOWISE data set and cannot yet be interpreted as describing the true populations; the debiased size and albedo distributions will be the subject of the next paper in this series.

  14. Using Combined THEMIS Visible and Infrared Images to map Martian Topography and Slope- corrected Surface Thermal Properties

    NASA Astrophysics Data System (ADS)

    Cushing, G. E.; Titus, T. N.; Soderblom, L. A.; Kirk, R. L.

    2007-12-01

    Kirk et al. (2005) empirically deconvolved visible and thermal-infrared THEMIS data, isolating topographic information that produced an accurate digital-terrain model (DTM). Described here is the next step wherein we use the same dataset (Columbia Hills area, Mars) in conjunction with the KRC thermal model (Kieffer et al., 1977) to quantitatively derive and map slope-corrected thermophysical properties. Observed surface temperatures, at high spatial resolution, are a function of many variables such as: slope, albedo, thermal inertia, time, season and atmospheric opacity. We constrain each of these variables to construct a DTM and maps of slope-corrected albedo, slope/albedo-corrected thermal inertia, and surface temperatures across an entire scene for any time of day or year and any atmospheric opacity. DTMs greatly facilitate analyses of the Martian surface, but generating these data is a challenge. The MOLA global dataset does not have sufficient resolution (~3 km) to be combined with newer datasets (e.g. HiRISE, CTX, THEMIS, MOC, and CRISM), so new techniques to derive high-resolution DTMs are always being explored. Stereo imaging produces quality, high-resolution DTMs but is limited in the amount of available coverage. Photoclinometry techniques on visible-wavelength images have been widely investigated with varying degrees of success, but accounting for albedo variations across a scene has been an historical weakness of this method. Here we discuss a technique of combining THEMIS visible and thermal infrared (both daytime and nighttime) observations (Christensen et al., 2004) in such a manner that albedo variations in the scene are cancelled, allowing the production of a high-resolution DTM via photoclinometry techniques that are largely free of albedo-induced errors. We employ the KRC thermal-diffusion model to generate models of slope-corrected thermal properties from the resultant DTM and THEMIS observations. This technique can provide new perspectives and

  15. Spectral albedos of midlatitude snowpacks

    NASA Technical Reports Server (NTRS)

    Choudhury, B.

    1981-01-01

    Spectral albedos of impure-nonhomogeneous snowpacks, typical of midlatitudes, from 400 to 2200 nm were modeled through a numerical solution of the radiative transfer equation in the two-stream approximation. Discrete depth-dependent values of density, grain size and impurity concentration were used to characterize the snowpacks. The model is for diffuse incident radiation, and the numerical method is based on doubling and invariant imbedding. The effect of soot impurities on snowpack albedos is illustrated when a snowpack is several centimeters deep and soot reduces the albedos at visible wavelengths, however, when a snowpack is only a few centimeters deep, soot may increase the albedos at visible wavelengths. By adjusting soot content and snow grain size, good quantitative agreement with some observations at the Cascade Mountains (Washington) and at Point Barrow (Alaska) are obtained; however, the model grain sizes are found to be fifty to four hundred percent larger than the measured values. For satellite snowcover observations, a model for effective albedo of partially snow-covered areas was developed and compared with some NOAA-2 observations of the southeastern United States.

  16. (25143) Itokawa: The power of radiometric techniques for the interpretation of remote thermal observations in the light of the Hayabusa rendezvous results*

    NASA Astrophysics Data System (ADS)

    Müller, Thomas G.; Hasegawa, Sunao; Usui, Fumihiko

    2014-06-01

    The near-Earth asteroid (25143) Itokawa was characterized in great detail by the Japanese Hayabusa mission. We revisited the available thermal observations in the light of the true asteroid properties with the goal of evaluating the possibilities and limitations of thermal model techniques. In total, we used 25 published ground-based mid-infrared photometric observations and five so far unpublished measurements from the Japanese infrared astronomical satellite AKARI in combination with improved H-G values (absolute magnitude and slope parameter). Our thermophysical model (TPM) approach allowed us to determine correctly the sense of rotation, to estimate the thermal inertia and to derive robust effective size and albedo values by only using a simple spherical shape model. A more complex shape model, derived from light-curve inversion techniques, improved the quality of the predictions considerably and made the interpretation of the thermal light curve possible. The radiometrically derived effective diameter value agrees within 2% with the true Itokawa size value. The combination of our TPM and the final (25143) Itokawa in-situ shape model was then used as a benchmark for deriving and testing radiometric solutions. The consolidated value for the surface-averaged thermal inertia is Γ = 700 ± 200 J m-2 s-0.5 K-1. We found that even the high-resolution shape models still require additional small-scale roughness in order to explain the disk-integrated infrared measurements. Our description of the thermal effects as a function of wavelengths, phase angle, and rotational phase facilitates the planning of crucial thermal observations for sophisticated characterization of small bodies, including other potentially hazardous asteroids. Our analysis shows the power of radiometric techniques to derive the size, albedo, thermal inertia, and also spin-axis orientation from small sets of measurements at thermal infrared wavelengths.

  17. Use of wrist albedo neutron dosimeters

    SciTech Connect

    Hankins, D.E.

    1983-01-01

    We are developing a wrist dosimeter that can be used to measure the exposure at the wrist to x-rays, gamma rays, beta-particles, thermal neutrons and fast neutrons. It consists of a modified Hankins Type albedo neutron dosimeter and also contains three pieces of CR-39 plastic. ABS plastic in the form of an elongated hemisphere provides the beta and low energy x-ray shielding necessary to meet the requirement of depth dose measurements at 1 cm. The dosimeter has a beta window located in the side of the hemisphere oriented towards an object being held in the hands. A TLD 600 is positioned under the 1 cm thick ABS plastic and is used to measure the thermal neutron dose. At present we are using Velcro straps to hold the dosimeter on the inside of the wrist. 9 figures.

  18. The role of inertia in models of the geodynamo

    NASA Astrophysics Data System (ADS)

    Fearn, D. R.; Rahman, M. M.

    2004-08-01

    that the addition of inertia (decreasing Pm) facilitates dynamo action; for a given level of forcing (i.e. fixed α0), increasing Eη results in an increased amplitude of the magnetic (and kinetic) energy. There is no shut-off of dynamo action with decreasing Pm as found in hydrodynamic models. This difference gives an insight into the various aspects of the dynamo process. By focusing on the field-generation process, using a fixed α that is independent of Eη, we have shown that inertia modifies the flow driven by the Lorentz force in a manner that is beneficial to field generation. The contrast between the present mean-field model and the results of hydrodynamic models shows that the effect of inertia on the driving process (thermal convection) is detrimental to field generation, more than compensating for the beneficial effect identified here.

  19. THE ALBEDOS OF KEPLER'S CLOSE-IN SUPER-EARTHS

    SciTech Connect

    Demory, Brice-Olivier

    2014-07-01

    Exoplanet research focusing on the characterization of super-Earths is currently limited to the handful of targets orbiting bright stars that are amenable to detailed study. This Letter proposes to look at alternative avenues to probe the surface and atmospheric properties of this category of planets, known to be ubiquitous in our galaxy. I conduct Markov Chain Monte Carlo light-curves analyses for 97 Kepler close-in R{sub P} ≲ 2.0 R {sub ⊕} super-Earth candidates with the aim of detecting their occultations at visible wavelengths. Brightness temperatures and geometric albedos in the Kepler bandpass are constrained for 27 super-Earth candidates. A hierarchical Bayesian modeling approach is then employed to characterize the population-level reflective properties of these close-in super-Earths. I find median geometric albedos A{sub g} in the Kepler bandpass ranging between 0.16 and 0.30, once decontaminated from thermal emission. These super-Earth geometric albedos are statistically larger than for hot Jupiters, which have medians A{sub g} ranging between 0.06 and 0.11. A subset of objects, including Kepler-10b, exhibit significantly larger albedos (A{sub g} ≳ 0.4). I argue that a better understanding of the incidence of stellar irradation on planetary surface and atmospheric processes is key to explain the diversity in albedos observed for close-in super-Earths.

  20. Thermal Properties of Unusual Local-Scale Features on Vesta

    NASA Technical Reports Server (NTRS)

    Capria, M.; DeSanctis, M.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.; Sunshine, J. M.; Titus, T. N.; Mittlefehldt, D. W.; Li, J.; Russell, C. T.; Raymond, C. A.

    2012-01-01

    On Vesta, the thermal behavior of areas of unusual albedo seen at the local scale can be related to physical properties that can provide information about the origin of those materials. We used Dawn s Visible and Infrared Mapping Spectrometer (VIR) hyperspectral cubes to retrieve surface temperatures and emissivities, with high accuracy as long as temperatures are greater than 180 K. Data acquired in the Survey phase (23 July through 29 August 2011) show several unusual surface features: 1) high-albedo (bright) and low-albedo (dark) material deposits, 2) spectrally distinct ejecta and pitted materials, 3) regions suggesting finer-grained materials. Some of the unusual dark and bright features were reobserved by VIR in the subsequent High-Altitude Mapping Orbit (HAMO) and Low- Altitude Mapping Orbit (LAMO) phases at increased pixel resolution. In this work we present temperature maps and emissivities of several local-scale features that were observed by Dawn under different illumination conditions and different local solar times. Data from VIR's IR channel show that bright regions generally correspond to regions with lower thermal emission, i.e. lower temperature, while dark regions correspond to areas with higher thermal emission, i.e. higher temperature. This behavior confirms that many of the dark appearances in the VIS mainly reflect albedo variations, and not, for example, shadowing. During maximum daily insolation, dark features in the equatorial region may rise to temperatures greater than 270 K, while brightest features stop at roughly 258 K, local solar time being similar. However, pitted materials, showing relatively low reflectance, have significantly lower temperatures, as a result of differences in composition and/or structure (e.g, average grain size of the surface regolith, porosity, etc.). To complement this work, we provide preliminary values of thermal inertia for some bright and dark features.

  1. Flapping inertia for selected rotor blades

    NASA Technical Reports Server (NTRS)

    Berry, John D.; May, Matthew J.

    1991-01-01

    Aerodynamics of helicopter rotor systems cannot be investigated without consideration for the dynamics of the rotor. One of the principal properties of the rotor which affects the rotor dynamics is the inertia of the rotor blade about its root attachment. Previous aerodynamic investigation have been performed on rotor blades with a variety of planforms to determine the performance differences due to blade planform. The blades tested for this investigation have been tested on the U.S. Army 2 meter rotor test system (2MRTS) in the NASA Langley 14 by 22 foot subsonic tunnel for hover performance. This investigation was intended to provide fundamental information on the flapping inertia of five rotor blades with differing planforms. The inertia of the bare cuff and the cuff with a blade extension were also measured for comparison with the inertia of the blades. Inertia was determined using a swing testing technique, using the period of oscillation to determine the effective flapping inertia. The effect of damping in the swing test was measured and described. A comparison of the flapping inertials for rectangular and tapered planform blades of approximately the same mass showed the tapered blades to have a lower inertia, as expected.

  2. Main-belt asteroids with WISE/NEOWISE: Near-infrared albedos

    SciTech Connect

    Masiero, Joseph R.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; Sonnett, S.

    2014-08-20

    We present revised near-infrared albedo fits of 2835 main-belt asteroids observed by WISE/NEOWISE over the course of its fully cryogenic survey in 2010. These fits are derived from reflected-light near-infrared images taken simultaneously with thermal emission measurements, allowing for more accurate measurements of the near-infrared albedos than is possible for visible albedo measurements. Because our sample requires reflected light measurements, it undersamples small, low-albedo asteroids, as well as those with blue spectral slopes across the wavelengths investigated. We find that the main belt separates into three distinct groups of 6%, 16%, and 40% reflectance at 3.4 μm. Conversely, the 4.6 μm albedo distribution spans the full range of possible values with no clear grouping. Asteroid families show a narrow distribution of 3.4 μm albedos within each family that map to one of the three observed groupings, with the (221) Eos family being the sole family associated with the 16% reflectance 3.4 μm albedo group. We show that near-infrared albedos derived from simultaneous thermal emission and reflected light measurements are important indicators of asteroid taxonomy and can identify interesting targets for spectroscopic follow-up.

  3. Low uncertainty method for inertia tensor identification

    NASA Astrophysics Data System (ADS)

    Barreto, J. P.; Muñoz, L. E.

    2016-02-01

    The uncertainty associated with the experimental identification of the inertia tensor can be reduced by implementing adequate rotational and translational motions in the experiment. This paper proposes a particular 3D trajectory that improves the experimental measurement of the inertia tensor of rigid bodies. Such a trajectory corresponds to a motion in which the object is rotated around a large number of instantaneous axes, while the center of gravity remains static. The uncertainty in the inertia tensor components obtained with this practice is reduced by 45% in average, compared with those calculated using simple rotations around three perpendicular axes (Roll, Pitch, Yaw).

  4. Weight, gravitation, inertia, and tides

    NASA Astrophysics Data System (ADS)

    Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe

    2015-11-01

    This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix.

  5. Numerical simulation on inertia controlled steam bubble condensation using MPS

    NASA Astrophysics Data System (ADS)

    Chong, Daotong; Ishiwatari, Yuki; Oka, Yoshiaki; Yan, Junjie; Liu, Jiping

    2013-07-01

    Bubble dynamics is quite complicated in the field of two-phase hydrodynamics because the interfacial heat and mass transfer is comprehensively affected by various influencing factors. Bubble condensation can be either thermally controlled or inertia controlled. Inertia controlled bubble condensation indicates that considerable pressure difference exists between the steam bubble and ambient liquid. In this paper, the inertia controlled steam bubble condensation was simulated using moving particle semi-implicit (MPS) method. The spherical bubble is located in the center of the cylindrical pool which makes the possibility of 2-D axisymmetric computation. The lateral and bottom wall are set to be rigid insulated boundaries and the top is free surface boundary. The pool volume must be large enough to eliminate the effects by pool wall. The initial bubble pressure ranges from 0.48 MPa to 3.98 MPa, and the initial bubble diameter ranges from 2 mm to 5 mm, and the ambient water pressure and temperature is 0.1 MPa and 70 °C, respectively. The bubble dynamics during condensation was investigated and the influences of initial bubble pressure and diameter were obtained. The bubble deformation during condensation is shown in figure 1, and the variations of bubble diameters and pressures during condensation are shown in figures 2 and 3, respectively.

  6. Detection of Surface Temperature Anomalies in the Coso Geothermal Field Using Thermal Infrared Remote Sensing

    NASA Astrophysics Data System (ADS)

    Coolbaugh, M.; Eneva, M.; Bjornstad, S.; Combs, J.

    2007-12-01

    We use thermal infrared (TIR) data from the spaceborne ASTER instrument to detect surface temperature anomalies in the Coso geothermal field in eastern California. The identification of such anomalies in a known geothermal area serves as an incentive to search for similar markers to areas of unknown geothermal potential. We carried out field measurements concurrently with the collection of ASTER images. The field data included reflectance, subsurface and surface temperatures, and radiosonde atmospheric profiles. We apply techniques specifically targeted to correct for thermal artifacts caused by topography, albedo, and thermal inertia. This approach has the potential to reduce data noise and to reveal thermal anomalies which are not distinguishable in the uncorrected imagery. The combination of remote sensing and field data can be used to evaluate the performance of TIR remote sensing as a cost-effective geothermal exploration tool.

  7. Electrohydrodynamics of a viscous drop with inertia.

    PubMed

    Nganguia, H; Young, Y-N; Layton, A T; Lai, M-C; Hu, W-F

    2016-05-01

    Most of the existing numerical and theoretical investigations on the electrohydrodynamics of a viscous drop have focused on the creeping Stokes flow regime, where nonlinear inertia effects are neglected. In this work we study the inertia effects on the electrodeformation of a viscous drop under a DC electric field using a novel second-order immersed interface method. The inertia effects are quantified by the Ohnesorge number Oh, and the electric field is characterized by an electric capillary number Ca_{E}. Below the critical Ca_{E}, small to moderate electric field strength gives rise to steady equilibrium drop shapes. We found that, at a fixed Ca_{E}, inertia effects induce larger deformation for an oblate drop than a prolate drop, consistent with previous results in the literature. Moreover, our simulations results indicate that inertia effects on the equilibrium drop deformation are dictated by the direction of normal electric stress on the drop interface: Larger drop deformation is found when the normal electric stress points outward, and smaller drop deformation is found otherwise. To our knowledge, such inertia effects on the equilibrium drop deformation has not been reported in the literature. Above the critical Ca_{E}, no steady equilibrium drop deformation can be found, and often the drop breaks up into a number of daughter droplets. In particular, our Navier-Stokes simulations show that, for the parameters we use, (1) daughter droplets are larger in the presence of inertia, (2) the drop deformation evolves more rapidly compared to creeping flow, and (3) complex distribution of electric stresses for drops with inertia effects. Our results suggest that normal electric pressure may be a useful tool in predicting drop pinch-off in oblate deformations. PMID:27300985

  8. Electrohydrodynamics of a viscous drop with inertia

    NASA Astrophysics Data System (ADS)

    Nganguia, H.; Young, Y.-N.; Layton, A. T.; Lai, M.-C.; Hu, W.-F.

    2016-05-01

    Most of the existing numerical and theoretical investigations on the electrohydrodynamics of a viscous drop have focused on the creeping Stokes flow regime, where nonlinear inertia effects are neglected. In this work we study the inertia effects on the electrodeformation of a viscous drop under a DC electric field using a novel second-order immersed interface method. The inertia effects are quantified by the Ohnesorge number Oh, and the electric field is characterized by an electric capillary number CaE. Below the critical CaE, small to moderate electric field strength gives rise to steady equilibrium drop shapes. We found that, at a fixed CaE, inertia effects induce larger deformation for an oblate drop than a prolate drop, consistent with previous results in the literature. Moreover, our simulations results indicate that inertia effects on the equilibrium drop deformation are dictated by the direction of normal electric stress on the drop interface: Larger drop deformation is found when the normal electric stress points outward, and smaller drop deformation is found otherwise. To our knowledge, such inertia effects on the equilibrium drop deformation has not been reported in the literature. Above the critical CaE, no steady equilibrium drop deformation can be found, and often the drop breaks up into a number of daughter droplets. In particular, our Navier-Stokes simulations show that, for the parameters we use, (1) daughter droplets are larger in the presence of inertia, (2) the drop deformation evolves more rapidly compared to creeping flow, and (3) complex distribution of electric stresses for drops with inertia effects. Our results suggest that normal electric pressure may be a useful tool in predicting drop pinch-off in oblate deformations.

  9. Efficient Computation Of Manipulator Inertia Matrix

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Bejczy, Antal K.

    1991-01-01

    Improved method for computation of manipulator inertia matrix developed, based on concept of spatial inertia of composite rigid body. Required for implementation of advanced dynamic-control schemes as well as dynamic simulation of manipulator motion. Motivated by increasing demand for fast algorithms to provide real-time control and simulation capability and, particularly, need for faster-than-real-time simulation capability, required in many anticipated space teleoperation applications.

  10. Inertia: An Important Consideration for Reading Motivation.

    ERIC Educational Resources Information Center

    Rasinski, Timothy V.

    The concept of inertia--the property by which a body in motion tends to remain in motion, and a body at rest tends to remain at rest--is analogous to a situation that occurs in reading. Some students, despite being able to read, choose not to read when other options are available. In terms of inertia, these students are at rest and tend to remain…

  11. Visual inertia of rotating 3-D objects.

    PubMed

    Jiang, Y; Pantle, A J; Mark, L S

    1998-02-01

    Five experiments were designed to determine whether a rotating, transparent 3-D cloud of dots (simulated sphere) could influence the perceived direction of rotation of a subsequent sphere. Experiment 1 established conditions under which the direction of rotation of a virtual sphere was perceived unambiguously. When a near-far luminance difference and perspective depth cues were present, observers consistently saw the sphere rotate in the intended direction. In Experiment 2, a near-far luminance difference was used to create an unambiguous rotation sequence that was followed by a directionally ambiguous rotation sequence that lacked both the near-far luminance cue and the perspective cue. Observers consistently saw the second sequence as rotating in the same direction as the first, indicating the presence of 3-D visual inertia. Experiment 3 showed that 3-D visual inertia was sufficiently powerful to bias the perceived direction of a rotation sequence made unambiguous by a near-far luminance cue. Experiment 5 showed that 3-D visual inertia could be obtained using an occlusion depth cue to create an unambiguous inertia-inducing sequence. Finally, Experiments 2, 4, and 5 all revealed a fast-decay phase of inertia that lasted for approximately 800 msec, followed by an asymptotic phase that lasted for periods as long as 1,600 msec. The implications of these findings are examined with respect to motion mechanisms of 3-D visual inertia. PMID:9529911

  12. Albedo in the ATIC Experiment

    NASA Technical Reports Server (NTRS)

    Sokolskaya, N. V.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Batkov, K. E.; Case, G.; Christl, M.; Chang, J.; Fazely, A. R.; Ganel, O.; Six, N. Frank (Technical Monitor)

    2002-01-01

    ATIC(Advanced Thin Ionization Calorimeter) is a balloon borne experiment designed to measure the cosmic ray composition for elements from hydrogen to iron and their energy spectra from approx.50 GeV to near 100 TeV. It consists of a Si-matrix detector to determine the charge of a CR particle, a scintillator hodoscope for tracking, carbon interaction targets and a fully active BGO calorimeter. ATIC had its first 16-day flight from McMurdo, Antarctica from 28/12/2000 to 13/01/2000. The ATIC flight collected approximately 25 million events. To measure charge of primary particle in presence of radiation scattered back from the interaction and subsequent shower development in the calorimeter a charge detector must be a mosaic of small detector pads so that the pad containing the signal from the incident particle has no additional signal from albedo particles. Therefore the silicon matrix was built of 4480 individual silicon pads each 2 cm x 1.5 cm. The matrix consists of four planes of detectors and the active detector area, in these planes are partially overlapped to completely cover the aperture. The lateral and amplitude distributions of albedo signals in Si-matrix are analyzed for different primary nuclei and different energy deposits in BGO calorimeter. The greater part of albedo signals has Q near 1, where Q = square root of Amplitude(MIP). The albedo distribution exponentially decreases up to Q near 8. These high values are produced by slow protons and plans. There are also a small number of signals of Q > 8, mainly for heavy nucleus primaries. These signals are apparently generated by neutrons. The comparison of the experimental data and simulations with GEANT 3-21 code using QGSM generator for nucleus-nucleus interactions is presented.

  13. Experimental Study of the Moment of Inertia of a Cone--Angular Variation and Inertia Ellipsoid

    ERIC Educational Resources Information Center

    Pintao, Carlos A. F.; de Souza Filho, Moacir P.; Usida, Wesley F.; Xavier, Jose A.

    2007-01-01

    In this paper, an experimental set-up which differs from the traditional ones is established in order to determine the moment of inertia of a right circular cone. Its angular variation and inertia ellipsoid are determined by means of an experimental study. In addition, a system that allows for the evaluation of the angular acceleration and torque…

  14. The albedo of snow for partially cloudy skies

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Chang, A. T. C.

    1981-01-01

    The albedo of snow is defined as the ratio of reflected to incident solar energy, and it is an important parameter in the earth's radiation budget analysis and in the study of snowpack's thermal conditions. An approximate model for calculating the incident spectral flux for partially cloudy skies is presented. The input parameters for the calculation are atmospheric precipitable water, turbidity, ozone content, surface pressure, the optical thickness of clouds, and the grain size of snow crystals. The spectral snow reflectance model considers both specular surface reflection and volumetric multiple scattering. The surface reflection is calculated by using a crystal-shape-dependent bidirectional reflectance distribution function; the volumetric multiple scattering is calculated by using a crystal-size-dependent approximate solution in the radiative transfer equation. The model yields spectral and integrated solar flux and snow reflectance as a function of solar elevation and fractional cloud-cover. The illustrative insolation and albedo values were obtained from spectral reflectance and incident flux for representative parameters of Antarctic coastal regions. A simple relationship between grain size and the overcast albedo was obtained. For a set of grain size and shape, the albedo as a function of solar elevation and fractional cloud cover was tabulated.

  15. Estimating the Inertia Matrix of a Spacecraft

    NASA Technical Reports Server (NTRS)

    Acikmese, Behcet; Keim, Jason; Shields, Joel

    2007-01-01

    A paper presents a method of utilizing some flight data, aboard a spacecraft that includes reaction wheels for attitude control, to estimate the inertia matrix of the spacecraft. The required data are digitized samples of (1) the spacecraft attitude in an inertial reference frame as measured, for example, by use of a star tracker and (2) speeds of rotation of the reaction wheels, the moments of inertia of which are deemed to be known. Starting from the classical equations for conservation of angular momentum of a rigid body, the inertia-matrix-estimation problem is formulated as a constrained least-squares minimization problem with explicit bounds on the inertia matrix incorporated as linear matrix inequalities. The explicit bounds reflect physical bounds on the inertia matrix and reduce the volume of data that must be processed to obtain a solution. The resulting minimization problem is a semidefinite optimization problem that can be solved efficiently, with guaranteed convergence to the global optimum, by use of readily available algorithms. In a test case involving a model attitude platform rotating on an air bearing, it is shown that, relative to a prior method, the present method produces better estimates from few data.

  16. The Ultraviolet Albedo of Ganymede

    NASA Astrophysics Data System (ADS)

    McGrath, Melissa; Hendrix, A.

    2013-10-01

    A large set of ultraviolet images of Ganymede have been acquired with the Hubble Space Telescope over the last 15 years. These images have been used almost exclusively to study Ganymede’s stunning auroral emissions (Feldman et al. 2000; Eviatar et al. 2001; McGrath et al. 2004; Saur et al. 2011; McGrath et al. 2013), and even the most basic information about Ganymede’s UV albedo has yet to be gleaned from these data. We will present a first-cut analysis of both disk-averaged and spatially-resolved UV albedos of Ganymede, with focus on the spatially-resolved Lyman-alpha albedo, which has never been considered previously for this satellite. Ganymede's visibly bright regions are known to be rich in water ice, while the visibly dark regions seem to be more carbonaceous (Carlson et al., 1996). At Lyman-alpha, these two species should also have very different albedo values. References Carlson, R. and 39 co-authors, Near-infrared spectroscopy and spectral mapping of Jupiter and the Galilean satellites: Results from Galileo’s initial orbit, Science, 274, 385-388, 1996. Eviatar, A., D. F. Strobel, B. C. Wolven, P. D. Feldman, M. A. McGrath, and D. J. Williams, Excitation of the Ganymede ultraviolet aurora, Astrophys. J, 555, 1013-1019, 2001. Feldman, P. D., M. A. McGrath, D. F. Strobel, H. W. Moos, K. D. Retherford, and B. C. Wolven, HST/STIS imaging of ultraviolet aurora on Ganymede, Astrophys. J, 535, 1085-1090, 2000. McGrath M. A., Lellouch E., Strobel D. F., Feldman P. D., Johnson R. E., Satellite Atmospheres, Chapter 19 in Jupiter: The Planet, Satellites and Magnetosphere, ed. F. Bagenal, T. Dowling, W. McKinnon, Cambridge University Press, 2004. McGrath M. A., Jia, Xianzhe; Retherford, Kurt; Feldman, Paul D.; Strobel, Darrell F.; Saur, Joachim, Aurora on Ganymede, J. Geophys. Res., doi: 10.1002/jgra.50122, 2013. Saur, J., S. Duling, S., L. Roth, P. D. Feldman, D. F. Strobel, K. D. Retherford, M. A. McGrath, A. Wennmacher, American Geophysical Union, Fall Meeting

  17. Nuclear moments of inertia at high spin

    SciTech Connect

    Deleplanque, M.A.

    1982-10-01

    The competition between collective motion and alignment at high spin can be evaluated by measuring two complementary dynamic moments of inertia. The first, I band, measured in ..gamma..-..gamma.. correlation experiments, relates to the collective properties of the nucleus. A new moment of inertia I/sub eff/ is defined here, which contains both collective and alignment effects. Both of these can be measured in continuum ..gamma..-ray spectra of rotational nuclei up to high frequencies. The evolution of ..gamma..-ray spectra for Er nuclei from mass 160 to 154 shows that shell effects can directly be observed in the spectra of the lighter nuclei.

  18. Albedo of Permanently Shadowed Regions of the Lunar Poles

    NASA Astrophysics Data System (ADS)

    Riner, M. A.; Lucey, P. G.; Bussey, B.; Cahill, J. T.; McGovern, A.

    2012-12-01

    limit is due to a complete loss of received laser signal as the spacecraft crosses the terminator due to thermal contraction of insulating blankets that pull the LOLA telescope out of alignment with the detectors. Fortuitously, two of the five laser spots reposition onto detectors after a transition period, so good laser range is obtained on a portion of the lunar night side. Additional calibration of night side reflectance data pole ward of 83° is ongoing [4]. The albedo of measured permanently shaded regions is 0.31 +/- 0.031 (1σ) compared to 0.31 +/- 0.033 (1σ) for measured sunlit regions from 60-80° north and south latitudes. This suggests that the high albedo of the floor of Shackleton is either unique or that the cause of the high albedo only acts at higher latitudes. Additional study of PSRs pole ward of 83° from LOLA night side data and examination of individual orbit tracks through PSRs may help elucidate the relationship between PSRs and albedo and contribute to understanding of these unique thermal environments, distribution of ice in PSRs, and volatile delivery and retention mechanisms. [1] Ingersoll et al. (1992) Icarus, 100, 40-47. [2] Smith et al. (2010) Space Sci. Rev., 150, 209-241. [3] Riner and Lucey (2011) AGU Fall Meeting, #P13D-1707. [4] Zuber et al. (2012) Nature, 486, 378-381. [5] McGovern et al. (2012), Icarus, accepted pending final review.

  19. The effects of dune slopes and material heterogeneity on the thermal behavior of dune fields in Mars' Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    O'Shea, P. M.; Putzig, N. E.; Van Kooten, S.; Fenton, L. K.

    2015-12-01

    We analyzed the effects of slopes on the thermal properties of three dune fields in Mars' southern hemisphere. Although slope has important thermal effects, it is not the main driver of observed apparent thermal inertia (ATI) for these dunes. Comparing the ATI seasonal behavior as derived from Thermal Emission Spectrometer (TES) data with that modeled for compositional heterogeneities, we found that TES results correlate best with models of duricrust overlying and/or horizontally mixing with fines. We measured slopes and aspects in digital terrain models created from High Resolution Imaging Science Experiment (HiRISE) images of dunes within Proctor, Kaiser, and Wirtz craters. Using the MARSTHERM web toolset, we incorporated the slopes and aspects together with TES albedo, TES thermal inertia, surface pressure, and TES dust opacity, into models of seasonal ATI. Models that incorporate sub-pixel slopes show seasonal day and night ATI values that differ from the TES results by 0-300 J m-2 K-1 s-½. In addition, the models' day-night differences are opposite in sign from those of the TES results, indicating that factors other than slope are involved. We therefore compared the TES data to model results for a broad range of horizontally mixed and two-layered surfaces to seek other possible controls on the observed data, finding that a surface layer of higher thermal inertia is a likely contributor. However, it is clear from this study that the overall composition and morphology of the dune fields are more complex than currently available models allow. Future work will combine slopes with other model parameters such as multi-layered surfaces and lateral changes in layer thickness. Coupling these improvements with broader seasonal coverage from the Thermal Emission Imaging System (THEMIS) at more thermally favorable times of day would allow more accurate characterization of dune thermal behavior.

  20. The temporal scale research of MODIS albedo product authenticity verification

    NASA Astrophysics Data System (ADS)

    Cao, Yongxing; Xue, Zhihang; Cheng, Hui; Xiong, Yajv; Chen, Yunping; Tong, Ling

    2016-06-01

    This study introduces a method that normalizes the inversed ETM+ albedo to the local solar noon albedo for the temporal scale of the MODIS albedo validation. Firstly, the statistical relation model between the surface albedo and the solar elevation angle was set up, and then deducing relationship between ETM+ albedo and the solar elevation angle, so the ETM+ albedo at local solar noon could be got. Secondly, the ground measurement albedo at the local solar noon was used to assess the inversed ETM+ albedo and the normalized albedo. The experiment results show that the method can effectively improve the accuracy of product certification.

  1. Near-ground cooling efficacies of trees and high-albedo surfaces

    SciTech Connect

    Levinson, R M

    1997-05-01

    Daytime summer urban heat islands arise when the prevalence of dark-colored surfaces and lack of vegetation make a city warmer than neighboring countryside. Two frequently-proposed summer heat island mitigation measures are to plant trees and to increase the albedo (solar reflectivity) of ground surfaces. This dissertation examines the effects of these measures on the surface temperature of an object near the ground, and on solar heating of air near the ground. Near-ground objects include people, vehicles, and buildings. The variation of the surface temperature of a near-ground object with ground albedo indicates that a rise in ground albedo will cool a near-ground object only if the object`s albedo exceeds a critical value. This critical value of object albedo depends on wind speed, object geometry, and the height of the atmospheric thermal boundary layer. It ranges from 0.15 to 0.37 for a person. If an object has typical albedo of 0.3, increasing the ground albedo by.

  2. Relations between albedos and emissivities from MODIS and ASTER data over North African Desert

    NASA Astrophysics Data System (ADS)

    Zhou, L.; Dickinson, R. E.; Ogawa, K.; Tian, Y.; Jin, M.; Schmugge, T.; Tsvetsinskaya, E.

    2003-10-01

    This paper analyzes relations among MODIS surface albedos, ASTER broadband (3-14 μm) emissivities, and a soil taxonomy map over the arid areas of Algeria, Libya, and Tunisia in North Africa at 30 second (about 1 km) and 2 minute (about 4 km) spatial resolutions. The MODIS albedo data are from 7 spectral bands and 3 broadbands during dust-free seasons and the emissivity data are derived from a linear combination of the waveband emissivities of the ASTER five thermal infrared channels. Both albedo and emissivity data in the study region show similar considerable spatial variability, larger than assumed by most climate models, and such variability is related to the surface types (sands, rock, and soil orders). Emissivity over bare soils exhibits statistically significant correlations with albedos at both broadbands and most of spectral bands and decreases linearly with albedos. Albedo and emissivity are more strongly correlated with each other than either is to the surface types, apparently because of their higher resolution either spatially or in surface mineralogy. This paper provides guidance for the possible inclusion of such correlation to specify albedo and emissivity in climate models.

  3. Autoclave test of inertia welded slugs

    SciTech Connect

    Peacock, H.B.

    1986-01-27

    Inertia welding (IW) is being evaluated as an alternative to gas-tungsten-arc (GTA) welding, for welding Mark 31 slugs. To demonstrate IW, 40 production (GTA) slugs rejected for pinholes and poor bonds were used. After welding, the slugs were autoclave tested. No autoclave failures occurred. (DLC)

  4. Effects of Inertia on Evolutionary Prisoner's Dilemma Game

    NASA Astrophysics Data System (ADS)

    Du, Wen-Bo; Cao, Xian-Bin; Liu, Run-Ran; Wang, Zhen

    2012-09-01

    Considering the inertia of individuals in real life, we propose a modified Fermi updating rule, where the inertia of players is introduced into evolutionary prisoner's dilemma game (PDG) on square lattices. We mainly focus on how the inertia affects the cooperative behavior of the system. Interestingly, we find that the cooperation level has a nonmonotonic dependence on the inertia: with small inertia, cooperators will soon be invaded by defectors; with large inertia, players are unwilling to change their strategies and the cooperation level remains the same as the initial state; while a moderate inertia can induce the highest cooperation level. Moreover, effects of environmental noise and individual inertia are studied. Our work may be helpful in understanding the emergence and persistence of cooperation in nature and society.

  5. The albedo, effective temperature, and energy balance of Uranus, as determined from Voyager IRIS data

    NASA Technical Reports Server (NTRS)

    Pearl, J. C.; Conrath, B. J.; Hanel, R. A.; Pirraglia, J. A.; Coustenis, A.

    1990-01-01

    The albedo, T(eff), and energy balance of Uranus are presently derived from Voyager IR Spectrometer and Radiometer data. By obtaining the absolute phase curve of Uranus, it has become possible to evaluate the Bond albedo without making separate determinations of the geometric albedo and phase integral. An orbital mean value for the bolometric Bond albedo of 0.3 + or - 0.049 yields an equilibrium temperature of 58.2 + or - 1.0 K. Thermal spectra from pole-to-pole latitude coverage establish a T(eff) of 59.1 + or - 0.3 K, leading to an energy balance of 1.06 + or - 0.08 for Uranus.

  6. The albedo, effective temperature, and energy balance of Uranus, as determined from Voyager IRIS data

    SciTech Connect

    Pearl, J.C.; Conrath, B.J.; Hanel, R.A.; Pirraglia, J.A.; Coustenis, A. Paris, Observatoire, Meudon )

    1990-03-01

    The albedo, T(eff), and energy balance of Uranus are presently derived from Voyager IR Spectrometer and Radiometer data. By obtaining the absolute phase curve of Uranus, it has become possible to evaluate the Bond albedo without making separate determinations of the geometric albedo and phase integral. An orbital mean value for the bolometric Bond albedo of 0.3 + or - 0.049 yields an equilibrium temperature of 58.2 + or - 1.0 K. Thermal spectra from pole-to-pole latitude coverage establish a T(eff) of 59.1 + or - 0.3 K, leading to an energy balance of 1.06 + or - 0.08 for Uranus. 39 refs.

  7. Migration of Frosts from High-Albedo Regions of Pluto: what New Horizons Reveals

    NASA Astrophysics Data System (ADS)

    Buratti, Bonnie J.; Stern, S. A.; Weaver, Hal A.; Young, Leslie A.; Olkin, Cathy B.; Ennico, Kimberly; Binzel, Richard P.; Zangari, Amanda; Earle, Alissa M.

    2015-11-01

    With its high eccentricity and obliquity, Pluto should exhibit seasonal volatile transport on its surface. Several lines of evidence support this transport: doubling of Pluto’s atmospheric pressure over the past two decades (Young et al., 2013, Ap. J. 766, L22; Olkin et al., 2015, Icarus 246, 230); changes in its historical rotational light curve, once all variations due to viewing geometry have been modelled (Buratti et al., 2015; Ap. J. 804, L6); and changes in HST albedo maps (Buie et al., 2010, Astron. J. 139, 1128). New Horizons LORRI images reveal that the region of greatest albedo change is not the polar cap(s) of Pluto, but the feature informally named Tombaugh Regio (TR). This feature has a normal reflectance as high as ~0.8 in some places, and it is superposed on older, lower-albedo pre-existing terrain with an albedo of only ~0.10. This contrast is larger than any other body in the Solar System, except for Iapetus. This albedo dichotomy leads to a complicated system of cold-trapping and thermal segregation, beyond the simple picture of seasonal volatile transport. Whatever the origin of TR, it initially acted as a cold trap, as the temperature differential between the high and low albedo regions could be enormous, possibly approaching 20K, based on their albedo differences and assuming their normalized phase curves are similar. This latter assumption will be refined as the full New Horizons data set is returned.Over six decades of ground-based photometry suggest that TR has been decreasing in albedo over the last 25 years. Possible causes include changing insolation angles, or sublimation from the edges where the high-albedo material impinges on a much warmer substrate.Funding by the NASA New Horizons Project acknowledged.

  8. A Model of Thermal Conductivity for Planetary Soils. 2; Theory for Cemented Soils

    NASA Technical Reports Server (NTRS)

    Piqueux, S.; Christensen, P. R.

    2009-01-01

    A numerical model of heat conduction through particulate media made of spherical grains cemented by various bonding agents is presented. The pore-filling gas conductivity, volume fraction, and thermal conductivity of the cementing phase are tunable parameters. Cement fractions <0.001-0.01% in volume have small effects on the soil bulk thermal conductivity. A significant conductivity increase (factor 3-8) is observed for bond fractions of 0.01 to 1% in volume. In the 1 to 15% bond fraction domain, the conductivity increases continuously but less intensely (25-100% conductivity increase compared to a 1% bond system). Beyond 15% of cements, the conductivity increases vigorously and the bulk conductivity rapidly approaches that of bedrock. The composition of the cements (i.e. conductivity) has little influence on the bulk thermal inertia of the soil, especially if the volume of bond <10%. These results indicate that temperature measurements are sufficient to detect cemented soils and quantify the amount of cementing phase, but the mineralogical nature of the bonds and the typical grain size are unlikely to be determined from orbit. On Mars, a widespread surface unit characterized by a medium albedo (0.19-0.26) and medium/high thermal inertia (200-600 J s(0.5)/sq m/K) has long been hypothesized to be associated with a duricrust. The fraction of cement required to fit the thermal data is less than approx.1-5% by volume. This small amount of material is consistent with orbital observations, confirming that soil cementation is an important factor controlling the thermal inertia of the Martian surface

  9. 40 CFR 1066.250 - Base inertia verification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... mean values as described in 40 CFR 1065.602(b). (7) Calculate the base inertia error, I berror, for... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Base inertia verification. 1066.250... CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.250 Base inertia verification....

  10. The Near-Earth Encounter of Asteroid 308635 (2005 YU55): Thermal IR Observations

    NASA Technical Reports Server (NTRS)

    Lim, Lucy F.; Emery, J. P.; Moskovitz, N. A.; Busch, N. W.; Yang, B.; Granvik, M.

    2012-01-01

    The near-Earth approach (0.00217 AU, or 0.845 lunar distances) of the C-type asteroid 308635 (2005 YU55) in November 2011 presented a rare opportunity for detailed observations of a low-albedo NEA in this size range. As part of a multi-telescope campaign to measure visible and infrared spectra and photometry, we obtained mid-infrared (approx. 8 to 22 micron) photometry and spectroscopy of 2005 YU55 using Michelle on the Gemini North telescope on UT November 9 and 10,2011. An extensive radar campaign together with optical light-curves established the rotation state of YU55. In addition, the radar imaging resulted in a shape model for the asteroid, detection of numerous boulders on its surface, and a preliminary estimate of its equatorial diameter at 380 +/- 20 m. In a preliminary analysis, applying the radar and lightcurve-derived parameters to a rough-surface thermophysical model fit to the Gemini/Michelle thermal emission photometry results in a thermal inertia range of approximately 500 to 1500 J/sq m/0.5s/K, with the low-thermal-inertia solution corresponding to the small end of the radar size range and vice versa. Updates to these results will be presented and modeling of the thermal contribution to the measured near-infrared spectra from Palomar/Triplespec and IRTF/SpeX will also be discussed.

  11. Inertia in Friedmann Universes with variable and

    NASA Astrophysics Data System (ADS)

    Sultana, J.; Kazanas, D.

    2015-09-01

    In light of the recent interest in dynamical dark energy models based on a cosmology with varying gravitational and cosmological parameters and , we present here a model of inertia in a type of Friedmann universe with ; being the dimensionless scale factor, that was recently studied by Singh et al. (Astrophys. Space Sci. 345:213, 2013). The proposed Machian model of inertia utilizes the curved space generalization of Sciama's law of inertial induction, which is based on the analogy between the retarded far fields of electrodynamics and those of gravitation, and expresses the total inertial force on an accelerating mass in terms of contributions from all matter in the observable Universe. We show that for a varying Friedmann model with , inertial induction alone can account for the total inertial force on the accelerating mass. We then compare this cosmological model with current observational constraints for the variation of.

  12. Inertia, gravitation, and radiation time delays

    SciTech Connect

    Graneau, P.

    1987-05-01

    This note explains how an instantaneous action-at-a-distance theory gives rise to time delays between a cause in one location and its effect at another. The key to this is a suitable law of induction which itself does not produce the time delay, but contains the cause in the form of a time derivative. The many-body solution process for an array of simultaneous induction equations then reveals retardation between cause and effect without the transport of energy at finite velocity. It is suggested that a suitable law of induction of inertia applied to an object in the solar system and the many-body universe may furnish the quantitative connection between inertia and Newtonian gravitation.

  13. On the Machian origin of inertia

    NASA Astrophysics Data System (ADS)

    Berman, Marcelo Samuel

    2008-12-01

    We examine Sciama’s inertia theory: we generalise it, by combining rotation and expansion in one unique model, we find the angular speed of the Universe, and we stress that the theory is zero-total-energy valued. We compare with other theories of the same null energy background. We determine the numerical value of a constant which appears in the Machian inertial force expression devised by Graneau and Graneau (In the Grip of the Distant Universe—the Science of Inertia, World Scientific, Singapore, 2006), by introducing the above angular speed. We point out that this last theory is not restricted to Newtonian physics as those authors stated but is, in fact, compatible with other cosmological and gravitational theories. An argument by Berry (Principles of Cosmology and Gravitation, Adam Hilger, Bristol, 1989) is shown in order to “derive” Brans-Dicke relation in the present context.

  14. Two-fluid turbulence including electron inertia

    SciTech Connect

    Andrés, Nahuel Gómez, Daniel; Gonzalez, Carlos; Martin, Luis; Dmitruk, Pablo

    2014-12-15

    We present a full two-fluid magnetohydrodynamic (MHD) description for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure, and electron inertia. According to this description, each plasma species introduces a new spatial scale: the ion inertial length λ{sub i} and the electron inertial length λ{sub e}, which are not present in the traditional MHD description. In the present paper, we seek for possible changes in the energy power spectrum in fully developed turbulent regimes, using numerical simulations of the two-fluid equations in two-and-a-half dimensions. We have been able to reproduce different scaling laws in different spectral ranges, as it has been observed in the solar wind for the magnetic energy spectrum. At the smallest wavenumbers where plain MHD is valid, we obtain an inertial range following a Kolmogorov k{sup −5∕3} law. For intermediate wavenumbers such that λ{sub i}{sup −1}≪k≪λ{sub e}{sup −1}, the spectrum is modified to a k{sup −7∕3} power-law, as has also been obtained for Hall-MHD neglecting electron inertia terms. When electron inertia is retained, a new spectral region given by k>λ{sub e}{sup −1} arises. The power spectrum for magnetic energy in this region is given by a k{sup −11∕3} power law. Finally, when the terms of electron inertia are retained, we study the self-consistent electric field. Our results are discussed and compared with those obtained in the solar wind observations and previous simulations.

  15. Nuclear moments of inertia at high spins

    SciTech Connect

    Deleplanque, M.A.

    1983-12-01

    Nuclei with highest angular momentum are discussed. The production of high spin states, and the basic ideas associated with high spin physics are reviewed. Recent developments from continuum ..gamma..-ray studies are presented: the measurement of different average moments of inertia gives new information on the interplay between collective and single particle aspects at high spins. Finally, the exciting possibility of resolving the continuum spectra with new detector systems is examined. 8 references.

  16. Two-fluid turbulence including electron inertia

    NASA Astrophysics Data System (ADS)

    Andrés, Nahuel; Gonzalez, Carlos; Martin, Luis; Dmitruk, Pablo; Gómez, Daniel

    2014-12-01

    We present a full two-fluid magnetohydrodynamic (MHD) description for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure, and electron inertia. According to this description, each plasma species introduces a new spatial scale: the ion inertial length λi and the electron inertial length λe, which are not present in the traditional MHD description. In the present paper, we seek for possible changes in the energy power spectrum in fully developed turbulent regimes, using numerical simulations of the two-fluid equations in two-and-a-half dimensions. We have been able to reproduce different scaling laws in different spectral ranges, as it has been observed in the solar wind for the magnetic energy spectrum. At the smallest wavenumbers where plain MHD is valid, we obtain an inertial range following a Kolmogorov k-5/3 law. For intermediate wavenumbers such that λi-1≪k ≪λe-1 , the spectrum is modified to a k-7/3 power-law, as has also been obtained for Hall-MHD neglecting electron inertia terms. When electron inertia is retained, a new spectral region given by k >λe-1 arises. The power spectrum for magnetic energy in this region is given by a k-11/3 power law. Finally, when the terms of electron inertia are retained, we study the self-consistent electric field. Our results are discussed and compared with those obtained in the solar wind observations and previous simulations.

  17. Variability of albedo and utility of the MODIS albedo product in forested wetlands

    USGS Publications Warehouse

    Sumner, David M.; Wu, Qinglong; Pathak, Chandra S.

    2011-01-01

    Albedo was monitored over a two-year period (beginning April 2008) at three forested wetland sites in Florida, USA using up- and down-ward facing pyranometers. Water level, above and below land surface, is the primary control on the temporal variability of daily albedo. Relatively low reflectivity of water accounts for the observed reductions in albedo with increased inundation of the forest floor. Enhanced canopy shading of the forest floor was responsible for lower sensitivity of albedo to water level at the most dense forest site. At one site, the most dramatic reduction in daily albedo was observed during the inundation of a highly-reflective, calcareous periphyton-covered land surface. Satellite-based Moderate-Resolution Imaging Spectroradiometer (MODIS) estimates of albedo compare favorably with measured albedo. Use of MODIS albedo values in net radiation computations introduced a root mean squared error of less than 4.7 W/m2 and a mean, annual bias of less than 2.3 W/m2 (1.7%). These results suggest that MODIS-estimated albedo values can reliably be used to capture areal and temporal variations in albedo that are important to the surface energy balance.

  18. Arctic sea ice albedo from AVHRR

    SciTech Connect

    Lindsay, R.W.; Rothrock, D.A.

    1994-11-01

    The seasonal cycle of surface albedo of sea ice in the Arctic is estimated from measurements made with the Advanced Very High Resolution Radiometer (AVHRR) on the polar-orbiting satellites NOAA-10 and NOAA-11. The albedos of 145 200-km-square cells are analyzed. The cells are from March through September 1989 and include only those for which the sun is more than 10 deg above the horizon. Cloud masking is performed manually. Corrections are applied for instrument calibration, nonisotropic reflection, atmospheric interference, narrowband to broadband conversion, and normalization to a common solar zenith angle. The estimated albedos are relative, with the instrument gain set to give an albedo of 0.80 for ice floes in March and April. The mean values for the cloud-free portions of individual cells range from 0.18 to 0.91. Monthly averages of cells in the central Arctic range from 0.76 in April to 0.47 in August. The monthly averages of the within-cell standard deviations in the central Arctic are 0.04 in April and 0.06 in September. The surface albedo and surface temperature are correlated most strongly in March (R = -0.77) with little correlation in the summer. The monthly average lead fraction is determined from the mean potential open water, a scaled representation of the temperature or albedo between 0.0 (for ice) and 1.0 (for water); in the central Arctic it rises from an average 0.025 in the spring to 0.06 in September. Sparse data on aerosols, ozone, and water vapor in the atmospheric column contribute uncertainties to instantaneous, area-average albedos of 0.13, 0.04, and 0.08. Uncertainties in monthly average albedos are not this large. Contemporaneous estimation of these variables could reduce the uncertainty in the estimated albedo considerably.

  19. Thermal Behaviour of Unusual Local-Scale Surface Features on Vesta

    NASA Technical Reports Server (NTRS)

    Tosi, F.; Capria, M. T.; De Sanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.-Ph.; Sunshine, J. M.; McCord, T. B.; Titus, T. N.; Russell, C. T.; Raymond, C. A.; Mittlefehldt, D. W.; Toplis, M. J.; Forni, O.; Sykes, M. V.

    2012-01-01

    On Vesta, the region of the infrared spectrum beyond approximately 3.5 micrometers is dominated by the thermal emission of the asteroid's surface, which can be used to determine surface temperature by means of temperature-retrieval algorithms. The thermal behavior of areas of unusual albedo seen at the local scale can be related to physical properties that can provide information about the origin of those materials. Dawn's Visible and Infrared Mapping Spectrometer (VIR) hyperspectral cubes are used to retrieve surface temperatures, with high accuracy as long as temperatures are greater than 180 K. Data acquired in the Survey phase (23 July through 29 August 2011) show several unusual surface features: 1) high-albedo (bright) and low-albedo (dark) material deposits, 2) spectrally distinct ejecta, 3) regions suggesting finer-grained materials. Some of the unusual dark and bright features were re-observed by VIR in the subsequent High-Altitude Mapping Orbit (HAMO) and Low-Altitude Mapping Orbit (LAMO) phases at increased pixel resolution. To calculate surface temperatures, we applied a Bayesian approach to nonlinear inversion based on the Kirchhoff law and the Planck function. These results were cross-checked through application of alternative methods. Here we present temperature maps of several local-scale features that were observed by Dawn under different illumination conditions and different local solar times. Some bright terrains have an overall albedo in the visible as much as 40% brighter than surrounding areas. Data from the IR channel of VIR show that bright regions generally correspond to regions with lower thermal emission, i.e. lower temperature, while dark regions correspond to areas with higher thermal emission, i.e. higher temperature. This behavior confirms that many of the dark appearances in the VIS mainly reflect albedo variations. In particular, it is shown that during maximum daily insolation, dark features in the equatorial region may rise to

  20. Thermal Emission Spectroscopy (5.2 To 38 Microns) And Analysis Of 10 Near-earth Asteroids

    NASA Astrophysics Data System (ADS)

    Dave, Riddhi; Emery, J.; Cruikshank, D.; Mueller, M.; Delbo, M.; Trilling, D. E.; Mommert, M.

    2010-10-01

    Near Earth Asteroids (NEAs- 0.983AUalbedo and size distribution of the NEAs is an essential prerequisite for exploring their physical nature, thermal properties, mineralogy, taxonomy and for developing reliable NEA population models. In support of the ExploreNEOs campaign of the Warm Spitzer program, we will present initial results from study of a sample of NEAs using the Infrared Spectrograph (IRS) on NASA's Spitzer Space Telescope [Programs 88 and 91- Extinct Comets and Low-Albedo Asteroids]. These data were reduced with Spitzer IRS Custom Extraction (SPICE) a JAVA-based tool built for interactive extraction of Spitzer IRS spectra. The 5.2-38 m thermal emission spectra[R 60-130] have been fitted with models of the thermal continuum employing the Near Earth Asteroid Thermal Model [NEATM](Harris 1998) and a Thermophysical model. Simultaneous measurements of the asteroid flux in the thermal infrared, combined with a thermal model, allow both the diameter and the albedo to be determined. The sample of Asteroids to be a part of this study are 1602 Geographos, 1580 Betulia, 433 Eros, 2212 Hephaistos, 1685 Toro, 1917 Cuyo, 1566 Icarus, 3200 Phaethon, 7092 Cadmus and 1866 Sisyphus. This study will give in-depth understanding of the applicability of the NEATM for NEAs observed at higher phase angles, having larger thermal inertia than main-belt asteroids, and/or displaying varied geometries. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  1. Spectral albedo and emissivity of CO2 in Martian polar caps - Model results

    NASA Technical Reports Server (NTRS)

    Warren, Stephen G.; Wiscombe, Warren J.; Firestone, John F.

    1990-01-01

    In this paper, a snow albedo model previously developed for terrestrial snow is extended to the case of CO2 snow on Mars. Pure CO2 snow is calculated to have high albedo at visible wavelengths but not as high as that of water snow. At any given wavelength, the primary variable controlling albedo and emissivity is the snow grain size, with albedo decreasing and emissivity increasing as grain size increases. Observations that red albedo is much higher than blue albedo in the Martian south polar cap indicates that the snow or the atmosphere is contaminated with red dust. The absorption coefficient of CO2 ice in the thermal infrared is two to three orders of magnitude smaller than that measured for H2O ice. CO2 snow emissivity is therefore much lower than H2O snow, varying substantially with wavelength and quite sensitive to grain size and emission angle. Factors tending to increase emissivity are large grain size, small emission angle, and large concentrations of dust or water.

  2. Albedo distribution of main-belt asteroids based on IRAS, AKARI, and WISE

    NASA Astrophysics Data System (ADS)

    Usui, F.; Hasegawa, S.; Ishiguro, M.; Mueller, T.; Ootsubo, T.

    2014-07-01

    Presently, the number of asteroids is known to be more than 630,000, and more than 90 % of asteroids with known orbital elements are classified as main-belt asteroids (MBAs). The spatial distribution of compositions among MBAs is of particular interest, because the main belt is the largest reservoir of asteroids in the solar system. Asteroids are thought to be the remnants of planetesimals formed in the early solar system, and allow us to study the formation and evolution of asteroids, origin of meteoroids and the near-Earth asteroids, as well as the formation of the solar system. Size and albedo are one of the most basic physical quantities of asteroid. Knowledge of size and albedo is essential in many aspects of asteroid research, such as the chemical composition and mineralogy, the size-frequency distribution of dynamical families and populations of asteroids, and the relationship between small bodies in the outer solar system and comets. Several techniques have been developed to determine the size of asteroids; by direct imaging with the Hubble Space Telescope or large ground-based telescopes with adaptive optics, radar observations, speckle interferometry, stellar occultation combined with lightcurve inversion techniques, and spacecraft flyby / rendezvous / sample return. One of the most effective methods for measuring asteroid size and albedo indirectly is through the use of radiometry, which combines information of the thermal emission (infrared flux) and the reflected sunlight (absolute magnitude). This method can provide unique data for asteroid size and albedo. Using radiometric measurements, a large number of objects can be observed in a short period of time, providing coherent data for large populations of asteroids within the asteroid belt. Infrared observations can be made still better under ideal circumstances, from space. The first space-borne infrared telescope is the Infrared Astronomical Satellite (IRAS; [1]), launched in 1983 and performed a

  3. Characterizing thermal features from multi-spectral remote sensing data using dynamic calibration procedures

    NASA Astrophysics Data System (ADS)

    Hardy, Colin C.

    A thermal infrared remote sensing project was implemented to develop methods for identifying, classifying, and mapping thermal features. This study is directed at geothermal features, with the expectation that new protocols developed here will apply to the wildland fire thermal environment. Airborne multi-spectral digital imagery was acquired over the geothermally active Norris Basin region of Yellowstone National Park, USA. Two image acquisitions were flown, with one near solar noon and the other at night. The five-band image data included thermal infrared (TIR), near-infrared (NIR), and three visible bandpasses. While focused on TIR, the study relied on the multi-spectral visible and NIR data as well as on an ancillary hyperspectral data set. The raw, five-band data were uncalibrated, requiring implementation of two calibration protocols. First, a vicarious calibration procedure was developed to compute reflectance for the visible and NIR bands using an independently calibrated hyperspectral dataset. Second, a dynamic, in-scene calibration procedure was developed for the thermal sensor that exploited natural, pseudo-invariant thermal reference targets instrumented with kinetic temperature recorders. A suite of thermal attributes was derived, including daytime and nighttime radiant temperatures, a temperature difference (DeltaT), albedo, one minus albedo, and apparent thermal inertia (ATI). The albedo terms were computed using a published weighed-average albedo algorithm based on ratios of the narrowband red and NIR reflectances to total solar irradiance for the respective red and NIR bandpasses. In the absence of verifiable "truth," a step-wise chain of unsupervised classification and multivariate analysis exercises was performed, drawing heavily on "fuzzy truth." A final classification synthesizes a "thermal phenomenology" comprised of four components: spectral, statistical, geographical/contextual, and feature space. In situ measurements paired with image data

  4. Mimas - Photometric roughness and albedo map

    NASA Technical Reports Server (NTRS)

    Verbiscer, Anne J.; Veverka, Joseph

    1992-01-01

    The backscattering phase function asssociated with bright icy satellites may render Hapke's (1986) isotropic approximation to multiple scattering inadequate. A reanalysis is accordingly conducted here of the Voyager observations of Mimas, using a modification to Hapke's equation that accommodates anisotropic multiple scattering, in order to characterize the physical and photometric properties of the heavily cratered icy surface. The roughness parameter of Mimas is in this way redefined, and an accurate albedo map is obtained which deminstrates small latitudinal and longitudinal albedo variations.

  5. The Albedo 'system' in the Cryosphere

    NASA Astrophysics Data System (ADS)

    Burkhart, J. F.; Storvold, R.; Solbo, S.; Pedersen, C. A.; Bogren, W.; Gerland, S.; Kylling, A.

    2012-12-01

    An Unmanned Aerial Vehicle (UAV) equipped with spectrometers making upward and downward measurements between 320-950nm was flown in Ny-Ålesund and Summit providing measurements of sea ice, ice sheet, and snow-covered tundra conditions. Concurrent with the flights, ground based stations with identical instrumentation were established. Micro snow pits and snow samples for black carbon analysis were collected at each measurement location. Preliminary analysis of the data show reflectance variability larger than albedo variability and more sensitive at longer wavelengths. This variability is driven by both the light absorbing aerosol component of the black carbon as well as physical aspects of the snow pack properties. At the each location, grain size variability, stratigraphy, and other physical snow pack properties are recorded. Analysis of black carbon content of the snow and inter-comparison with satellite retrieved measurements of albedo is ongoing. In this presentation the multiple measurements of albedo show that traditional measurements and estimates of albedo lack adequate characterization of the system within which the measurements are being made. Albedo is not a property of the surface being measured, but rather a property of a system and dependent on multiple parameters within the system that change seasonally, daily, and even hourly. We examine this system, and identify areas for improvement in current albedo parameterizations in the cryosphere.

  6. Brownian transport in corrugated channels with inertia

    NASA Astrophysics Data System (ADS)

    Ghosh, P. K.; Hänggi, P.; Marchesoni, F.; Nori, F.; Schmid, G.

    2012-08-01

    Transport of suspended Brownian particles dc driven along corrugated narrow channels is numerically investigated in the regime of finite damping. We show that inertial corrections cannot be neglected as long as the width of the channel bottlenecks is smaller than an appropriate particle diffusion length, which depends on the the channel corrugation and the drive intensity. With such a diffusion length being inversely proportional to the damping constant, transport through sufficiently narrow obstructions turns out to be always sensitive to the viscosity of the suspension fluid. The inertia corrections to the transport quantifiers, mobility, and diffusivity markedly differ for smoothly and sharply corrugated channels.

  7. Inertia in the Brazil nut problem

    NASA Astrophysics Data System (ADS)

    Nahmad-Molinari, Y.; Canul-Chay, G.; Ruiz-Suárez, J. C.

    2003-10-01

    The rise dynamics of a large particle, in a granular bed under vertical vibrations, is experimentally studied with an inductive device designed to track the particle while it climbs through the granulate under different conditions. A model based on energy considerations is presented to explain our experimental data, drawing the important conclusion that it is the inertia of the particle, assisted by Reynolds dilatancy, the driven force behind its ascension mechanism. The ascension reveals a friction profile within the column which remains unchanged for different accelerations.

  8. Canned pump having a high inertia flywheel

    DOEpatents

    Veronesi, L.; Raimondi, A.A.

    1989-12-12

    A canned pump is described which includes a motor, impeller, shaft, and high inertia flywheel mounted within a hermetically sealed casing. The flywheel comprises a heavy metal disk made preferably of a uranium alloy with a stainless steel shell sealably enclosing the heavy metal. The outside surfaces of the stainless steel comprise thrust runners and a journal for mating with, respectively, thrust bearing shoes and radial bearing segments. The bearings prevent vibration of the pump and, simultaneously, minimize power losses normally associated with the flywheel resulting from frictionally pumping surrounding fluid. 5 figs.

  9. Canned pump having a high inertia flywheel

    DOEpatents

    Veronesi, Luciano; Raimondi, ALbert A.

    1989-01-01

    A canned pump is described which includes a motor, impeller, shaft, and high inertia flywheel mounted within a hermetically sealed casing. The flywheel comprises a heavy metal disk made preferably of a uranium alloy with a stainless steel shell sealably enclosing the heavy metal. The outside surfaces of the stainless steel comprise thrust runners and a journal for mating with, respectively, thrust bearing shoes and radial bearing segments. The bearings prevent vibration of the pump and, simultaneously, minimize power losses normally associated with the flywheel resulting from frictionally pumping surrounding fluid.

  10. Characterizing Thermal features in Norris Basin, Yellowstone National Park, Using Multi- spectral Remote Sensing Data and Dynamic Calibration Procedures

    NASA Astrophysics Data System (ADS)

    Hardy, C. C.; Queen, L. P.; Heasler, H. P.; Jaworowski, C.

    2007-12-01

    A thermal infrared remote sensing project was implemented to develop methods for identifying, classifying, and mapping thermal features. This study is directed at geothermal features, with the expectation that new protocols developed here will apply to the wildland fire thermal environment. Airborne multi-spectral digital imagery were acquired over the geothermally active Norris Basin region of Yellowstone National Park, USA. Two image acquisitions were flown, with one acquisition near solar noon and the other at night. Raw data from the five sensors were uncalibrated, so a vicarious calibration procedure was developed to compute reflectance for the visible and NIR bands using an independently calibrated hyperspectral dataset. Calibration of the thermal sensor band utilized a dynamic, in-scene calibration procedure that exploited natural, pseudo-invariant thermal reference targets instrumented with in situ kinetic temperature recorders. The calibrated reflectance and radiant temperature data from each acquisition were processed and analyzed to develop a suite of thermal attributes, including radiant temperatures, a daytime-nighttime temperature difference (DeltaT), albedo, an albedo derivative (one minus albedo), and apparent thermal inertia (ATI). The albedo terms were computed using a published weighed-average albedo algorithm based on ratios of the narrowband red and near-infrared (NIR) reflectances to total solar irradiance for the respective red and NIR bandpasses. The weighing factors for each band were the proportion of total solar irradiance incident on the surface within each segment represented by a respective bandpass. In the absence of verifiable "truth," a step-wise chain of unsupervised classification and multivariate analysis exercises was performed, drawing heavily on "fuzzy truth" to assess the quality, efficiency, and efficacy of classification procedures and results. A final classification synthesizes a "geothermal phenomenology" comprised of

  11. Sea ice-albedo climate feedback mechanism

    SciTech Connect

    Schramm, J.L.; Curry, J.A.; Ebert, E.E.

    1995-02-01

    The sea ice-albedo feedback mechanism over the Arctic Ocean multiyear sea ice is investigated by conducting a series of experiments using several one-dimensional models of the coupled sea ice-atmosphere system. In its simplest form, ice-albedo feedback is thought to be associated with a decrease in the areal cover of snow and ice and a corresponding increase in the surface temperature, further decreasing the area cover of snow and ice. It is shown that the sea ice-albedo feedback can operate even in multiyear pack ice, without the disappearance of this ice, associated with internal processes occurring within the multiyear ice pack (e.g., duration of the snow cover, ice thickness, ice distribution, lead fraction, and melt pond characteristics). The strength of the ice-albedo feedback mechanism is compared for several different thermodynamic sea ice models: a new model that includes ice thickness distribution., the Ebert and Curry model, the Mayjut and Untersteiner model, and the Semtner level-3 and level-0 models. The climate forcing is chosen to be a perturbation of the surface heat flux, and cloud and water vapor feedbacks are inoperative so that the effects of the sea ice-albedo feedback mechanism can be isolated. The inclusion of melt ponds significantly strengthens the ice-albedo feedback, while the ice thickness distribution decreases the strength of the modeled sea ice-albedo feedback. It is emphasized that accurately modeling present-day sea ice thickness is not adequate for a sea ice parameterization; the correct physical processes must be included so that the sea ice parameterization yields correct sensitivities to external forcing. 22 refs., 6 figs., 1 tab.

  12. Surface Albedo and Spectral Variability of Ceres

    NASA Astrophysics Data System (ADS)

    Li, Jian-Yang; Reddy, Vishnu; Nathues, Andreas; Le Corre, Lucille; Izawa, Matthew R. M.; Cloutis, Edward A.; Sykes, Mark V.; Carsenty, Uri; Castillo-Rogez, Julie C.; Hoffmann, Martin; Jaumann, Ralf; Krohn, Katrin; Mottola, Stefano; Prettyman, Thomas H.; Schaefer, Michael; Schenk, Paul; Schröder, Stefan E.; Williams, David A.; Smith, David E.; Zuber, Maria T.; Konopliv, Alexander S.; Park, Ryan S.; Raymond, Carol A.; Russell, Christopher T.

    2016-02-01

    Previous observations suggested that Ceres has active, but possibly sporadic, water outgassing as well as possibly varying spectral characteristics over a timescale of months. We used all available data of Ceres collected in the past three decades from the ground and the Hubble Space Telescope, as well as the newly acquired images by the Dawn  Framing Camera, to search for spectral and albedo variability on Ceres, on both a global scale and in local regions, particularly the bright spots inside the Occator crater, over timescales of a few months to decades. Our analysis has placed an upper limit on the possible temporal albedo variation on Ceres. Sporadic water vapor venting, or any possibly ongoing activity on Ceres, is not significant enough to change the albedo or the area of the bright features in the Occator crater by >15%, or the global albedo by >3% over the various timescales that we searched. Recently reported spectral slope variations can be explained by changing Sun-Ceres-Earth geometry. The active area on Ceres is less than 1 km2, too small to cause global albedo and spectral variations detectable in our data. Impact ejecta due to impacting projectiles of tens of meters in size like those known to cause observable changes to the surface albedo on Asteroid Scheila cannot cause detectable albedo change on Ceres due to its relatively large size and strong gravity. The water vapor activity on Ceres is independent of Ceres’ heliocentric distance, ruling out the possibility of the comet-like sublimation process as a possible mechanism driving the activity.

  13. Surface Albedo and Spectral Variability of Ceres

    NASA Astrophysics Data System (ADS)

    Li, Jian-Yang; Reddy, Vishnu; Nathues, Andreas; Le Corre, Lucille; Izawa, Matthew R. M.; Cloutis, Edward A.; Sykes, Mark V.; Carsenty, Uri; Castillo-Rogez, Julie C.; Hoffmann, Martin; Jaumann, Ralf; Krohn, Katrin; Mottola, Stefano; Prettyman, Thomas H.; Schaefer, Michael; Schenk, Paul; Schröder, Stefan E.; Williams, David A.; Smith, David E.; Zuber, Maria T.; Konopliv, Alexander S.; Park, Ryan S.; Raymond, Carol A.; Russell, Christopher T.

    2016-02-01

    Previous observations suggested that Ceres has active, but possibly sporadic, water outgassing as well as possibly varying spectral characteristics over a timescale of months. We used all available data of Ceres collected in the past three decades from the ground and the Hubble Space Telescope, as well as the newly acquired images by the Dawn  Framing Camera, to search for spectral and albedo variability on Ceres, on both a global scale and in local regions, particularly the bright spots inside the Occator crater, over timescales of a few months to decades. Our analysis has placed an upper limit on the possible temporal albedo variation on Ceres. Sporadic water vapor venting, or any possibly ongoing activity on Ceres, is not significant enough to change the albedo or the area of the bright features in the Occator crater by >15%, or the global albedo by >3% over the various timescales that we searched. Recently reported spectral slope variations can be explained by changing Sun–Ceres–Earth geometry. The active area on Ceres is less than 1 km2, too small to cause global albedo and spectral variations detectable in our data. Impact ejecta due to impacting projectiles of tens of meters in size like those known to cause observable changes to the surface albedo on Asteroid Scheila cannot cause detectable albedo change on Ceres due to its relatively large size and strong gravity. The water vapor activity on Ceres is independent of Ceres’ heliocentric distance, ruling out the possibility of the comet-like sublimation process as a possible mechanism driving the activity.

  14. On the moment of inertia of a quantum harmonic oscillator

    SciTech Connect

    Khamzin, A. A. Sitdikov, A. S.; Nikitin, A. S.; Roganov, D. A.

    2013-04-15

    An original method for calculating the moment of inertia of the collective rotation of a nucleus on the basis of the cranking model with the harmonic-oscillator Hamiltonian at arbitrary frequencies of rotation and finite temperature is proposed. In the adiabatic limit, an oscillating chemical-potential dependence of the moment of inertia is obtained by means of analytic calculations. The oscillations of the moment of inertia become more pronounced as deformations approach the spherical limit and decrease exponentially with increasing temperature.

  15. Albedo, internal heat, and energy balance of Jupiter, preliminary results of the Voyager infrared investigation

    NASA Technical Reports Server (NTRS)

    Hanel, R. A.; Conrath, B. J.; Herath, L. W.; Kunde, V. G.; Pirraglia, J. A.

    1980-01-01

    The in flight calibration of the radiometer and the Michelson interferometer of the Voyager 1 infrared instrument is discussed. The calibrated full disk measurements are applied to derive values of the albedo, the thermal emission and the global energy balance of Jupiter.

  16. Synchrophasor Measurement-Based Wind Plant Inertia Estimation: Preprint

    SciTech Connect

    Zhang, Y.; Bank, J.; Wan, Y. H.; Muljadi, E.; Corbus, D.

    2013-05-01

    The total inertia stored in all rotating masses that are connected to power systems, such as synchronous generations and induction motors, is an essential force that keeps the system stable after disturbances. To ensure bulk power system stability, there is a need to estimate the equivalent inertia available from a renewable generation plant. An equivalent inertia constant analogous to that of conventional rotating machines can be used to provide a readily understandable metric. This paper explores a method that utilizes synchrophasor measurements to estimate the equivalent inertia that a wind plant provides to the system.

  17. Nuclear moment of inertia and spin distribution of nuclear levels

    SciTech Connect

    Alhassid, Y.; Fang, L.; Liu, S.; Bertsch, G.F.

    2005-12-15

    We introduce a simple model to calculate the nuclear moment of inertia at finite temperature. This moment of inertia describes the spin distribution of nuclear levels in the framework of the spin-cutoff model. Our model is based on a deformed single-particle Hamiltonian with pairing interaction and takes into account fluctuations in the pairing gap. We derive a formula for the moment of inertia at finite temperature that generalizes the Belyaev formula for zero temperature. We show that a number-parity projection explains the strong odd-even effects observed in shell model Monte Carlo studies of the nuclear moment of inertia in the iron region.

  18. A cavity radiometer for Earth albedo measurement, phase 1

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Radiometric measurements of the directional albedo of the Earth requires a detector with a flat response from 0.2 to 50 microns, a response time of about 2 seconds, a sensitivity of the order of 0.02 mw/sq cm, and a measurement uncertainty of less than 5 percent. Absolute cavity radiometers easily meet the spectral response and accuracy requirements for Earth albedo measurements, but the radiometers available today lack the necessary sensitivity and response time. The specific innovations addressed were the development of a very low thermal mass cavity and printed/deposited thermocouple sensing elements which were incorporated into the radiometer design to produce a sensitive, fast response, absolute radiometer. The cavity is applicable to the measurement of the reflected and radiated fluxes from the Earth surface and lower atmosphere from low Earth orbit satellites. The effort consisted of requirements and thermal analysis; design, construction, and test of prototype elements of the black cavity and sensor elements to show proof-of-concept. The results obtained indicate that a black body cavity sensor that has inherently a flat response from 0.2 to 50 microns can be produced which has a sensitivity of at least 0.02 mw/sq cm per micro volt ouput and with a time constant of less than two seconds. Additional work is required to develop the required thermopile.

  19. Gamma-ray Albedo of the Moon

    SciTech Connect

    Moskalenko, Igor V.; Porter, Troy A.

    2007-06-14

    We use the GEANT4 Monte Carlo framework to calculate the gamma-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of gamma-rays from the Moon is very steep with an effective cutoff around 3 GeV (600 MeV for the inner part of the Moon disc). Since it is the only (almost) black spot in the gamma-ray sky, it provides a unique opportunity for calibration of gamma-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The albedo flux depends on the incident CR spectrum which changes over the solar cycle. Therefore, it is possible to monitor the CR spectrum using the albedo gamma-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo -rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the GLAST LAT to monitor the CR spectrum near the Earth beyond the lifetime of PAMELA.

  20. Thermal Behavior of Unusual Local-Scale Features on Vesta

    NASA Technical Reports Server (NTRS)

    Tosi, Federico; Capria, Maria Teresa; DeSanctis, Maria Cristina; Palomba, Ernesto; Capaccioni, Fabrizio; Combe, Jean-Philippe; Titus, Timothy; Mittlefehldt, David W.; Li, Jian-Yang; Russell, Christopher T.

    2012-01-01

    On Vesta, the thermal behavior of areas of unusual albedo seen at the local scale can be related to physical properties that can provide information about the origin of those materials. Dawn's Visible and Infrared Mapping Spectrometer (VIR) hyperspectral cubes are used to retrieve surface temperatures and emissivities, with high accuracy as long as temperatures are greater than 180 K. Data acquired in the Survey phase (23 July through 29 August 2011) show several unusual surface features: 1) high-albedo (bright) and low-albedo (dark) material deposits, 2) spectrally distinct ejecta and pitted materials, 3) regions suggesting finer-grained materials. Some of the unusual dark and bright features were re-observed by VIR in the subsequent High-Altitude Mapping Orbit (HAMO) and Low-Altitude Mapping Orbit (LAMO) phases at increased pixel resolution. In particular, bright and dark surface materials on Vesta, and pitted materials, are currently being investigated by the Dawn team. In this work we present temperature maps and emissivities of several local-scale features that were observed by Dawn under different illumination conditions and different local solar times. To calculate surface temperatures, we applied a Bayesian approach to nonlinear inversion based on the Kirchhoff law and the Planck function, and whose results were compared with those provided by the application of alternative methods. Data from the IR channel of VIR show that bright regions generally correspond to regions with lower thermal emission, i.e. lower temperature, while dark regions correspond to areas with higher thermal emission, i.e. higher temperature. This behavior confirms that many of the dark appearances in the VIS mainly reflect albedo variations, and not, for example, shadowing. During maximum daily insolation, dark features in the equatorial region may rise to temperatures greater than 270 K, while brightest features stop at roughly 258 K for similar local solar times. However, pitted

  1. Albedo and color contrasts on asteroid surfaces

    NASA Technical Reports Server (NTRS)

    Degewij, J.; Tedesco, E. F.; Zellner, B.

    1979-01-01

    Asteroids in general display only small or negligible variations in spectrum or albedo during a rotational cycle. Color variations with rotation are described in the literature but are usually comparable to the noise in the measurements. Twenty-four asteroids have been systematically monitored for such color changes. Only 3 Juno, 4 Vesta, 6 Hebe, 71 Niobe, 349 Dembowska, and 944 Hidalgo display color variations larger than 0.03 mag. In each of these cases the asteroid appears redder near maximum brightness. Of seven asteroids monitored polarimetrically, only 4 Vesta shows a convincing variation, attributed to an albedo change with rotation. The lightcurve can be explained by albedo differences alone; Vesta apparently has a nearly spheroidal shape. Nothwithstanding the above results, the degree of uniformity of most asteroid surfaces is remarkable. If asteroids exist with large discrete domains of ferrosilicate, metallic, and/or carbonaceous material together on their surfaces, they have not yet been identified.

  2. The determination of surface albedo from meteorological satellites

    NASA Technical Reports Server (NTRS)

    Johnson, W. T.

    1977-01-01

    A surface albedo was determined from visible data collected by the NOAA-4 polar orbiting meteorological satellite. To filter out the major cause of atmospheric reflectivity, namely clouds, techniques were developed and applied to the data resulting in a map of global surface albedo. Neglecting spurious surface albedos for regions with persistent cloud cover, sun glint effects, insufficient reflected light and, at this time, some unresolved influences, the surface albedos retrieved from satellite data closely matched those of a global surface albedo map produced from surface and aircraft measurements and from characteristic albedos for land type and land use.

  3. Multiscale climatological albedo look-up maps derived from moderate resolution imaging spectroradiometer BRDF/albedo products

    NASA Astrophysics Data System (ADS)

    Gao, Feng; He, Tao; Wang, Zhuosen; Ghimire, Bardan; Shuai, Yanmin; Masek, Jeffrey; Schaaf, Crystal; Williams, Christopher

    2014-01-01

    Surface albedo determines radiative forcing and is a key parameter for driving Earth's climate. Better characterization of surface albedo for individual land cover types can reduce the uncertainty in estimating changes to Earth's radiation balance due to land cover change. This paper presents albedo look-up maps (LUMs) using a multiscale hierarchical approach based on moderate resolution imaging spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo products and Landsat imagery. Ten years (2001 to 2011) of MODIS BRDF/albedo products were used to generate global albedo climatology. Albedo LUMs of land cover classes defined by the International Geosphere-Biosphere Programme (IGBP) at multiple spatial resolutions were generated. The albedo LUMs included monthly statistics of white-sky (diffuse) and black-sky (direct) albedo for each IGBP class for visible, near-infrared, and shortwave broadband under both snow-free and snow-covered conditions. The albedo LUMs were assessed by using the annual MODIS IGBP land cover map and the projected land use scenarios from the Intergovernmental Panel on Climate Change land-use harmonization project. The comparisons between the reconstructed albedo and the MODIS albedo data product show good agreement. The LUMs provide high temporal and spatial resolution global albedo statistics without gaps for investigating albedo variations under different land cover scenarios and could be used for land surface modeling.

  4. Monitoring surface albedo change with Landsat

    NASA Technical Reports Server (NTRS)

    Otterman, J.

    1977-01-01

    A pronounced decrease of the surface albedo (reflectivity) has been observed in an area in the Northern Sinai, fenced-in in the summer of 1974. Analysis of the Landsat Multispectral Scanner System digital data from an April 1977 pass indicates a reduction in the albedo in the exclosure by 13%, as compared to the outside, which continues to be subjected to overgrazing and anthropogenic pressures. The reduction of reflectivity is approximately the same in all the spectral bands, and is therefore attributable to accumulation of dead plants and plant debris, and not directly to live vegetation.

  5. The diameter and albedo of 1943 Anteros

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.; Tedesco, E. F.; Tholen, D. J.; Tokunaga, A.; Matthews, K.; Neugebauer, G.; Soifer, B. T.; Kowal, C.

    1981-01-01

    The results of broadband visual and infrared photometry of the Apollo-Amor asteroid 1943 Anteros during its 1980 apparition are reported. By means of a radiometric model, a diameter of 2.3 + or - 0.2 km and a visual geometric albedo of 0.13 + or - 0.03 is calculated. The albedo and reflectance spectrum of Anteros imply that it is a type S asteroid. Thus, Anteros may have a silicate surface similar to other Apollo-Amor asteroids as well as some stony-iron meteorites.

  6. The ultraviolet continuum albedo of Uranus

    SciTech Connect

    Cochran, W.D.; Wagener, R.; Caldwell, J.; Fricke, K.H. New York State Univ., Stony Brook York Univ., Toronto Bonn Universitaet )

    1990-01-01

    A radiative transfer code explicitly treating the Raman scattering of solar protons by H{sub 2} is presently used to analyze the Uranus geometric albedo in the 2000-5000 A range. The Baines and Bergstralh (1986) baseline model used reproduces the geometric albedo peak produced by Raman scattering filling of solar absorption line cores, but is found to be excessively bright for wavelengths below 2400 A. This discrepancy is resolvable through inclusion of an absorbing stratospheric haze layer, and results are thereby obtained which are consistent with the Pollack et al. (1987) model, in which aerosols are generated stratospherically through photochemical effects on hydrocarbons. 20 refs.

  7. Modified Gravity and the origin of inertia

    NASA Astrophysics Data System (ADS)

    Moffat, J. W.; Toth, V. T.

    2009-05-01

    Modified gravity theory is known to violate Birkhoff's theorem. We explore a key consequence of this violation, the effect of distant matter in the Universe on the motion of test particles. We find that when a particle is accelerated, a force is experienced that is proportional to the particle's mass and acceleration and acts in the direction opposite to that of the acceleration. We identify this force with inertia. At very low accelerations, our inertial law deviates slightly from that of Newton, yielding a testable prediction that may be verified with relatively simple experiments. Our conclusions apply to all gravity theories that reduce to a Yukawa-like force in the weak-field approximation.

  8. The moments of inertia of Mars

    NASA Technical Reports Server (NTRS)

    Bills, Bruce G.

    1989-01-01

    The mean moment of inertia of Mars is, at present, very poorly constrained. The generally accepted value of 0.365 M(R-squared) is obtained by assuming that the observed second degree gravity field can be decomposed into a hydrostatic oblate spheroid and a nonhydrostatic prolate spheroid with an equatorial axis of symmetry. An alternative decomposition is advocated in the present analysis. If the nonhydrostatic component is a maximally triaxial ellipsoid (intermediate moment exactly midway between greatest and least), the hydrostatic component is consistent with a mean moment of 0.345 M(R-squared). The plausibility of this decomposition is supported by statistical arguments and comparison with the earth, moon and Venus.

  9. Using NASTRAN to model missile inertia loads

    NASA Technical Reports Server (NTRS)

    Marvin, R.; Porter, C.

    1985-01-01

    An important use of NASTRAN is in the area of structural loads analysis on weapon systems carried aboard aircraft. The program is used to predict bending moments and shears in missile bodies, when subjected to aircraft induced accelerations. The missile, launcher and aircraft wing are idealized, using rod and beam type elements for solution economy. Using the inertia relief capability of NASTRAN, the model is subjected to various acceleration combinations. It is found to be difficult to model the launcher sway braces and hooks which transmit compression only or tension only type forces respectively. A simple, iterative process was developed to overcome this modeling difficulty. A proposed code modification would help model compression or tension only contact type problems.

  10. 40 CFR 1066.250 - Base inertia verification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... inertia mean values as described in 40 CFR 1065.602(b) (8) Calculate the inertia error for the final base... acceleration rate and the nominal deceleration rate. (4) Use good engineering judgment to select two additional acceleration and deceleration rate pairs that cover the middle and upper rates expected during testing....

  11. Fission as diffusion of a Brownian particle with variable inertia

    SciTech Connect

    Sadhukhan, Jhilam; Pal, Santanu

    2010-08-15

    An expression for stationary fission width is obtained for systems with steep shape-dependent nuclear collective inertia by extending the work of Kramers, which was originally derived for a fixed value of the inertia. The domain of validity of the present expression is examined by comparing its predictions with widths obtained from the corresponding Langevin equations.

  12. Magnetic suspension options for spacecraft inertia-wheel applications

    NASA Technical Reports Server (NTRS)

    Downer, J. R.

    1984-01-01

    Design criteria for spacecraft inertia-wheel suspensions are listed. The advantages of magnetic suspensions over other suspension types for spacecraft inertia-wheel applications are cited along with the functions performed by magnetic suspension. The common designs for magnetic suspensions are enumerated. Materials selection of permanent magnets and core materials is considered.

  13. Moments of Inertia of Disks and Spheres without Integration

    ERIC Educational Resources Information Center

    Hong, Seok-Cheol; Hong, Seok-In

    2013-01-01

    Calculation of moments of inertia is often challenging for introductory-level physics students due to the use of integration, especially in non-Cartesian coordinates. Methods that do not employ calculus have been described for finding the rotational inertia of thin rods and other simple bodies. In this paper we use the parallel axis theorem and…

  14. Thermal and shape properties of asteroid (21) Lutetia from Herschel observations around the Rosetta flyby

    NASA Astrophysics Data System (ADS)

    O'Rourke, L.; Müller, T.; Valtchanov, I.; Altieri, B.; González-Garcia, B. M.; Bhattacharya, B.; Jorda, L.; Carry, B.; Küppers, M.; Groussin, O.; Altwegg, K.; Barucci, M. A.; Bockelee-Morvan, D.; Crovisier, J.; Dotto, E.; Garcia-Lario, P.; Kidger, M.; Llorente, A.; Lorente, R.; Marston, A. P.; Sanchez Portal, M.; Schulz, R.; Sierra, M.; Teyssier, D.; Vavrek, R.

    2012-06-01

    Prior to and around the Rosetta flyby of (21) Lutetia, the Herschel Space Observatory performed a collaborative observation campaign with its two photometers observing the asteroid in the far infrared, at wavelengths not covered by Rosetta's instruments. The Herschel observations, fed into a thermophysical model (TPM) using as input a shape model based on in-situ images, were also further correlated with ˜70 multi-wavelength observations of Lutetia. We confirm the geometric albedo measured by Rosetta, derive a H-mag value based upon the effective diameter of the asteroid and point to (21) Lutetia having an extremely low thermal inertia (5 J m-2 s-0.5 K-1). This thermal inertia is only possible through the existence of a significant amount of small scale roughness which is not directly observable by the OSIRIS (Optical, Spectroscopic, and Infrared Imaging System) instrument on-board Rosetta. In addition, our results point to the existence of a hill/crater surface feature located on the asteroids southern region not observed by Rosetta. From our results, we conclude that only through the merging of in situ and remote sensing observations can a true global picture be obtained of this asteroid.

  15. Inferring heat recirculation and albedo for exoplanetary atmospheres: Comparing optical phase curves and secondary eclipse data

    NASA Astrophysics Data System (ADS)

    von Paris, P.; Gratier, P.; Bordé, P.; Selsis, F.

    2016-03-01

    Context. Basic atmospheric properties, such as albedo and heat redistribution between day- and nightsides, have been inferred for a number of planets using observations of secondary eclipses and thermal phase curves. Optical phase curves have not yet been used to constrain these atmospheric properties consistently. Aims: We model previously published phase curves of CoRoT-1b, TrES-2b, and HAT-P-7b, and infer albedos and recirculation efficiencies. These are then compared to previous estimates based on secondary eclipse data. Methods: We use a physically consistent model to construct optical phase curves. This model takes Lambertian reflection, thermal emission, ellipsoidal variations, and Doppler boosting, into account. Results: CoRoT-1b shows a non-negligible scattering albedo (0.11 < AS < 0.3 at 95% confidence) as well as small day-night temperature contrasts, which are indicative of moderate to high re-distribution of energy between dayside and nightside. These values are contrary to previous secondary eclipse and phase curve analyses. In the case of HAT-P-7b, model results suggest a relatively high scattering albedo (AS ≈ 0.3). This confirms previous phase curve analysis; however, it is in slight contradiction to values inferred from secondary eclipse data. For TrES-2b, both approaches yield very similar estimates of albedo and heat recirculation. Discrepancies between recirculation and albedo values as inferred from secondary eclipse and optical phase curve analyses might be interpreted as a hint that optical and IR observations probe different atmospheric layers, hence temperatures.

  16. Thermal Studies of Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Pilorz, S.; Altobelli, N.; Leyrat, C.; Spilker, L.

    2007-12-01

    The observed thermal emission from Saturn's rings has a locational and directional variation that ultimately results from the time dependent response of individual ring particles to the quasi-periodic radiation forcing they experience as they orbit Saturn. The observed thermal emission from any radial region of the rings is representative of a large ensemble of particles or structures which are subject to statistically similar conditions as they orbit. Near any particular radius, the thermal forcing and response are quasi-periodic around an orbit, varying secularly with Saturn's twenty-nine year seasonal cycle. This talk will discuss the coupled thermal and radiative transfer processes within the rings as determined by the interplay between individual particle properties and those of the ensemble (i.e., the ring structure), and the constraints that are placed on those by the most comprehensive thermal observations of the rings to date, taken with the Cassini Infrared Spectrometer (CIRS). Over one hundred thousand thermal-infrared spectra of the rings, between 10 and 500 cm-1, have been taken with the CIRS Focal Plane 1 (FP1) detector since Cassini orbit insertion in July, 2004. They resemble scaled Planck functions with well resolved peaks indicative of temperatures between approximately 60 and 120 K. We investigate the properties of a mapping from a space of physical parameters describing ring particles and their distribution onto predicted time-dependent spectral thermal emission. Ring emission is modeled using a radiative transfer code augmented with ray tracing calculations; a thermal model is embedded within the calculation to model the particles as a thermal source, and statistical averaging is incorporated. The model is specified by a vector of parameters describing a vertically varying particle size distribution, spin distribution, thermal inertia, albedo and optical depth, and when driven by radiation calculated from ephemeris parameters it produces a self

  17. Spectral albedo of seasonal snow during intensive melt period at Sodankylä, beyond the Arctic Circle

    NASA Astrophysics Data System (ADS)

    Meinander, O.; Kazadzis, S.; Arola, A.; Riihelä, A.; Räisänen, P.; Kivi, R.; Kontu, A.; Kouznetsov, R.; Sofiev, M.; Svensson, J.; Suokanerva, H.; Aaltonen, V.; Manninen, T.; Roujean, J.-L.; Hautecoeur, O.

    2013-04-01

    We have measured spectral albedo, as well as ancillary parameters, of seasonal European Arctic snow at Sodankylä, Finland (67°22' N, 26°39' E). The springtime intensive melt period was observed during the Snow Reflectance Transition Experiment (SNORTEX) in April 2009. The upwelling and downwelling spectral irradiance, measured at 290-550 nm with a double monochromator spectroradiometer, revealed albedo values of ~0.5-0.7 for the ultraviolet and visible range, both under clear sky and variable cloudiness. During the most intensive snowmelt period of four days, albedo decreased from 0.65 to 0.45 at 330 nm, and from 0.72 to 0.53 at 450 nm. In the literature, the UV and VIS albedo for clean snow are ~0.97-0.99, consistent with the extremely small absorption coefficient of ice in this spectral region. Our low albedo values were supported by two independent simultaneous broadband albedo measurements, and simulated albedo data. We explain the low albedo values to be due to (i) large snow grain sizes up to ~3 mm in diameter; (ii) meltwater surrounding the grains and increasing the effective grain size; (iii) absorption caused by impurities in the snow, with concentration of elemental carbon (black carbon) in snow of 87 ppb, and organic carbon 2894 ppb, at the time of albedo measurements. The high concentrations of carbon, detected by the thermal-optical method, were due to air masses originating from the Kola Peninsula, Russia, where mining and refining industries are located.

  18. The ultraviolet spectral albedo of planet earth

    NASA Technical Reports Server (NTRS)

    Frederick, John E.; Serafino, George N.

    1987-01-01

    The solar backscattered ultraviolet spectral radiometer on the Nimbus 7 satellite provides a unique set of radiation measurements which allows an evaluation of the spectral albedo of the earth and its atmosphere in the wavelength range 300 to 340 nm. Near 340 nm, the derived spectral albedo expressed as a function of latitude and month exceeds that in the visible part of the spectrum, with values near 45 percent existing equatorward of 30 deg and an increase to 60-80 percent toward the poles. At middle to high latitudes, the monthly mean spectral albedo exceeds the contribution from Rayleigh scattering alone by factors of 1.4 to 2.2. At wavelengths from 300 to 310 nm, where absorption by stratospheric ozone is significant, the daylight averaged spectral albedos receive negligible contribution from scattering by tropospheric clouds, yet the derived values exceed those predicted for Rayleigh scattering from a clean stratosphere. These observations are consistent with the presence of an atmospheric scattering layer, distinct from cloudiness, located at an altitude above the tropopause.

  19. The low energy atmospheric antiproton albedo

    NASA Technical Reports Server (NTRS)

    Cole, J. B.; Ormes, J. F.

    1989-01-01

    The flux of albedo antiprotons in the 100-1000 MeV kinetic energy range produced by the cosmic ray primaries in the atmosphere is calculated. It is shown that this is not a significant background to measurements of the low energy anti-proton cosmic ray flux.

  20. UV signatures of carbonaceous species on low-albedo asteroids

    NASA Astrophysics Data System (ADS)

    Hendrix, A.; Vilas, F.

    2014-07-01

    Asteroids in the low-albedo classes (C, B, G, F) are known to have spectra that are relatively feature-free in the visible/near-infrared (VNIR) spectral region, making them classically difficult to study in terms of surface mineralogy. Many of these bodies exhibit a 3-micron absorption band (e.g., [1]), which can be used to study hydration and organics. The primary other spectrally active region --- less well studied so far --- is the ultraviolet (UV). In this study, we utilize UV spectra of low-albedo asteroids (C, B, G, and F class) to study surface composition. In particular, we investigate implications for the presence of carbonaceous compounds, including tholins and Polycyclic Aromatic Hydrocarbons (PAHs), which have unique spectral features in the UV. Low-albedo asteroids are typically rather bland spectrally at VNIR wavelengths. Many of these objects exhibit an absorption band near 3 microns, indicative of some type of hydration (OH and-or H_2O). A subset of the asteroids with the 3-micron features also exhibit absorption near 0.7 microns, due to a ferrous-ferric charge-transfer transition likely resulting from aqueous alteration (the interaction of material with liquid water formed by melting of water upon a heating event). Some asteroids likely do not exhibit these features due to a history of heating experienced at some point in the asteroid's evolution. Despite having little spectral activity in the VNIR, all low-albedo asteroids absorb at wavelengths shorter than ˜500 nm. This has been generally attributed to a ferric-iron intervalence charge-transfer transition absorption. Carbon-bearing phases have long been assumed to be important on low-albedo asteroids (e.g., [2]) due to the dark, mostly-featureless VNIR spectra of these bodies. However, there are many forms of carbonaceous species and the species are expected to undergo phase modifications (e.g., due to thermal, aqueous, and radiation processes) that affect the spectra [3,7]. Tholins are residues

  1. The albedo of fractal stratocumulus clouds

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Ridgway, William; Wiscombe, Warren J.; Bell, Thomas L.; Snider, Jack B.

    1994-01-01

    An increase in the planetary albedo of the earth-atmosphere system by only 10% can decrease the equilibrium surface temperature to that of the last ice age. Nevertheless, albedo biases of 10% or greater would be introduced into large regions of current climate models if clouds were given their observed liquid water amounts, because of the treatment of clouds as plane parallel. The focus on marine stratocumulus clouds is due to their important role in cloud radiative forcing and also that, of the wide variety of earth's cloud types, they are most nearly plane parallel, so that they have the least albedo bias. The fractal model employed here reproduces both the probability distribution and the wavenumber spectrum of the stratocumulus liquid water path, as observed during the First ISCCP Regional Experiment (FIRE). A single new fractal parameter 0 less than or equal to f less than or equal to 1, is introduced and determined empirically by the variance of the logarithm of the vertically integrated liquid water. The reduced reflectivity of fractal stratocumulus clouds is approximately given by the plane-parallel reflectivity evaluated at a reduced 'effective optical thickness,' which when f = 0.5 is tau(sub eff) approximately equal to 10. Study of the diurnal cycle of stratocumulus liquid water during FIRE leads to a key unexpected result: the plane-parallel albedo bias is largest when the cloud fraction reaches 100%, that is, when any bias associated with the cloud fraction vanishes. This is primarily due to the variability increase with cloud fraction. Thus, the within-cloud fractal structure of stratocumulus has a more significant impact on estimates of its mesoscale-average albedo than does the cloud fraction.

  2. Albedo boundaries on Mars in 1972: Results from Mariner 9

    USGS Publications Warehouse

    Batson, R.M.; Inge, J.L.

    1976-01-01

    A map of "albedo" boundaries (light and dark markings) on Mars was prepared from Mariner 9 images. After special digital processing, these pictures provide detailed locations of albedo boundaries, which is significant in interpreting recent eolian activity. Derivation of absolute albedo values from the spacecraft data was not attempted. The map correlates well with telescopic observations of Mars after the 1971 dust storm. ?? 1976.

  3. Determination of physical properties of the Asteroid (41) Daphne from interferometric observations in the thermal infrared

    NASA Astrophysics Data System (ADS)

    Matter, Alexis; Delbo, Marco; Ligori, Sebastiano; Crouzet, Nicolas; Tanga, Paolo

    2011-09-01

    We describe interferometric observations of the Asteroid (41) Daphne in the thermal infrared obtained with the Mid-Infrared Interferometric Instrument (MIDI) and the Auxiliary Telescopes (ATs) of the European Southern Observatory (ESO) Very Large Telescope Interferometer (VLTI). We derived the size and the surface thermal properties of (41) Daphne by means of a thermophysical model (TPM), which is used for the interpretation of interferometric data for the first time. From our TPM analysis, we derived a volume equivalent diameter for (41) Daphne of 189 km, using a non-convex 3-D shape model derived from optical lightcurves and adaptive optics images (B. Carry, private communication). On the other hand, when using the convex shape of Kaasalainen et al. (Kaasalainen, M., Mottola, S., Fulchignoni, M. [2002]. Icarus 159, 369-395) in our TPM analysis, the resulting volume equivalent diameter of (41) Daphne is between 194 and 209 km, depending on the surface roughness. The shape of the asteroid is used as an a priori information in our TPM analysis. No attempt is made to adjust the shape to the data. Only the size of the asteroid and its thermal parameters such as, albedo, thermal inertia and roughness are adjusted to the data. We estimated our model systematic uncertainty to be of 4% and of 7% on the determination of the asteroid volume equivalent diameter depending on whether the non-convex or the convex shape is used, respectively. In terms of thermal properties, we derived a value of the surface thermal inertia smaller than 50 J m -2 s -0.5 K -1 and preferably in the range between 0 and ˜30 J m -2 s -0.5 K -1. Our TPM analysis also shows that Daphne has a moderate macroscopic surface roughness.

  4. Using scaling to compute moments of inertia of symmetric objects

    NASA Astrophysics Data System (ADS)

    Ricardo, Bernard

    2015-09-01

    Moment of inertia is a very important property in the study of rotational mechanics. The concept of moment of inertia is analogous to mass in the linear motion, and its calculation is routinely done through integration. This paper provides an alternative way to compute moments of inertia of rigid bodies of regular shape using their symmetrical property. This approach will be very useful and preferred for teaching rotational mechanics at the undergraduate level, as it does not require the knowledge or the application of calculus. The seven examples provided in this paper will help readers to understand clearly how to use the method.

  5. The Albedo Dichotomy of Iapetus Measured at UV Wavelengths

    NASA Technical Reports Server (NTRS)

    Hendrix, Amanda R.; Hansen, Candice J.

    2007-01-01

    The dramatic hemispheric dichotomy in albedo displayed by Saturn's moon Iapetus has intrigued astronomers for centuries. Here we report on far-ultraviolet observations of Iapetus' bright and dark terrains from Cassini. We compare the reflectance spectra of Iapetus's dark terrain, Hyperion and Phoebe and find that both Phoebe and Hyperion are richer in water ice than Iapetus' dark terrain. Spectra of the lowest latitudes of the dark terrain display the diagnostic water ice absorption feature; water ice amounts increase within the dark material away from the apex (at 90 deg W longitude, the center of the dark leading hemisphere), consistent with thermal segregation of water ice. The water ice in the darkest, warmest low latitude regions is not expected to be stable and may be a sign of ongoing or recent emplacement of the dark material from an exogenic source.

  6. Estimating big bluestem albedo from directional reflectance measurements

    NASA Technical Reports Server (NTRS)

    Irons, J. R.; Ranson, K. J.; Daughtry, C. S. T.

    1988-01-01

    Multidirectional reflectance factor measurements acquired in the summer of 1986 are used to make estimates of big bluestem grass albedo, evaluating the variation of albedo with changes in solar zenith angle and phenology. On any given day, the albedo was observed to increase by at least 19 percent as solar zenith angle increased. Changes in albedo were found to correspond to changes in the green leaf area index of the grass canopy. Estimates of albedo made using reflectance data acquired within only one or two azimuthal planes and at a restricted range of view zenith angle were evaluated and compared to 'true' albedos derived from all available reflectance factor data. It was found that even a limited amount of multiple direction reflectance data was preferable to a single nadir reflectance factor for the estimation of prarie grass albedo.

  7. Calibration system for albedo neutron dosimeters

    SciTech Connect

    Rothermich, N.E.

    1981-01-01

    Albedo neutron dosimeters have proven to be effective as a method of measuring the dose from neutron exposures that other types of neutron detectors cannot measure. Results of research conducted to calibrate an albedo neutron dosemeter are presented. The calibration procedure consisted of exposing the TLD chips to a 46 curie /sup 238/PuBe source at known distances, dose rates and exposure periods. The response of the TLD's is related to the dose rate measured with a dose rate meter to obtain the calibration factor. This calibration factor is then related to the ratio of the counting rates determined by 9-inch and 3-inch Bonner spheres (also called remmeters) and a calibration curve was determined. 17 references, 10 figures, 3 tables.

  8. The albedo of particles in reflection nebulae

    NASA Technical Reports Server (NTRS)

    Rush, W. F.

    1974-01-01

    The relation between the apparent angular extent of a reflection nebula and the apparent magnitude of its illuminating star was reconsidered under a less restrictive set of assumptions. A computational technique was developed which permits the use of fits to the observed m-log a values to determine the albedo of particles composing reflection nebulae, providing only that a phase function and average optical thickness are assumed. Multiple scattering, anisotropic phase functions, and illumination by the general star field are considered, and the albedo of reflection nebular particles appears to be the same as that for interstellar particles in general. The possibility of continuous fluorescence contributions to the surface brightness is also considered.

  9. Earth Albedo and the orbit of LAGEOS

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.; Weiss, N. R.

    1985-01-01

    The long-period perturbations in the orbit of the Lageos satellite due to the Earth's albedo have been found using a new analytical formalism. The Earth is assumed to be a sphere whose surface diffusely reflects sunlight according to Lambert's law. Specular reflection is not considered. The formalism is based on spherical harmonics; it produces equations which hold regardless of whether the terminator is seen by the satellite or not. Specializing to the case of a realistic zonal albedo shows that Lageos' orbital semimajor axis changes periodically by only the a few millimeters and the eccentricity by one part in 100,000. The longitude of the node increases secularly. The effect considered here can explain neither the secular decay of 1.1 mm/day in the semimajor axis nor the observed along-track variations in acceleration of order 2 x 10 to the minus 12 power/sq ms.

  10. Geomorphological related albedo features on Ceres

    NASA Astrophysics Data System (ADS)

    Krohn, K.; Matz, K.-D.; Jaumann, R.; Otto, K.; Li, J.-Y.; Buczkowski, D.; Mest, S.; Scully, J. E. C.; Williams, D. A.; Raymond, C. A.; Russell, C. T.

    2015-10-01

    NASA's Dawn spacecraft entered orbit of Ceres on March 6, 2015, to spend one year characterizing the geology, elemental and mineralogical composition, topography, shape, and internal structure of the Ceres [1]. Ceres is supposed to be differentiated into a silicate core, a liquid water mantle and a solid ice crust with a surface temperature from 130K to 235K [2,3]. At the time of writing, the acquired image data from Ceres provide a spatial resolution of up to 2.1 km/pixel. The surface of Ceres reveals some albedo features that seem to be related to geomorphology. Those features show either a high or a low albedo compared to the surrounding.

  11. Anomaly of the moment of inertia of shape transitional nuclei

    SciTech Connect

    Gupta, J. B.; Hamilton, J. H.

    2011-06-15

    The change in the structure of the collective levels with spin angular momentum in atomic nuclei is often expressed in terms of the classical concepts of the kinematic and the dynamic moments of inertia varying with spin. For the well deformed even-even nuclei the kinematic moment of inertia increases with spin up to 10%-20%, at say I{sup {pi}} = 12{sup +}. However, for the shape transitional nuclei, or almost spherical nuclei, it increases with spin much faster. The pitfalls of using the rotor model form of kinematic moment of inertia in such cases are pointed out here. Alternative methods of extracting the nuclear structure information are explored. The important role of the ground state deformation is illustrated. The use of the power index formula for evaluating the effective moment of inertia, free from the assumption of the rotor model, is described.

  12. Climatic effects of surface albedo geoengineering

    NASA Astrophysics Data System (ADS)

    Irvine, Peter J.; Ridgwell, Andy; Lunt, Daniel J.

    2011-12-01

    Various surface albedo modification geoengineering schemes such as those involving desert, urban, or agricultural areas have been proposed as potential strategies for helping counteract the warming caused by greenhouse gas emissions. However, such schemes tend to be inherently limited in their potential and would create a much more heterogeneous radiative forcing than propositions for space-based "reflectors" and enhanced stratospheric aerosol concentrations. Here we present results of a series of atmosphere-ocean general circulation model (GCM) simulations to compare three surface albedo geoengineering proposals: urban, cropland, and desert albedo enhancement. We find that the cooling effect of surface albedo modification is strongly seasonal and mostly confined to the areas of application. For urban and cropland geoengineering, the global effects are minor but, because of being colocated with areas of human activity, they may provide some regional benefits. Global desert geoengineering, which is associated with significant global-scale changes in circulation and the hydrological cycle, causes a smaller reduction in global precipitation per degree of cooling than sunshade geoengineering, 1.1% K-1 and 2.0% K-1 respectively, but a far greater reduction in the precipitation over land, 3.9% K-1 compared with 1.0% K-1. Desert geoengineering also causes large regional-scale changes in precipitation with a large reduction in the intensity of the Indian and African monsoons in particular. None of the schemes studied reverse the climate changes associated with a doubling of CO2, with desert geoengineering profoundly altering the climate and with urban and cropland geoengineering providing only some regional amelioration at most.

  13. Thermal Studies of Near Earth Objects

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    2003-01-01

    In this proposal, we seek to apply the optical/thermal method to the measurement of the diameters and albedos of a large sample of Near Earth Objects (NEOs). Whereas main-belt asteroids have been studied in large numbers, principally using thermal detections from the IRAS satellite, relatively few thermal observations of NEOs have been secured. This program capitalizes on our access to large telescopes and imaging thermal IR detectors in pursuit of the definitive set of albedo data on the NEOs.

  14. Juno radio science observations to constrain Jupiter's moment of inertia

    NASA Astrophysics Data System (ADS)

    Le Maistre, S.; Folkner, W. M.; Jacobson, R. A.

    2015-10-01

    Through detailed and realistic numerical simulations, the present study assesses the precision with which Juno can measure the normalized polar moment of inertia (MOI) of Jupiter. Based on Ka-band Doppler and range data, this analysis shows that the determination of the precession rate of Jupiter is by far more efficient than the previously proposed Lense-Thirring effect to determine the moment of inertia and therefore to constrain the internal structure of the giant planet with Juno.

  15. Data Citation Impediments: Human and Institutional Inertia

    NASA Astrophysics Data System (ADS)

    Mayernik, M. S.

    2013-12-01

    Data citations are growing in visibility in scientific and public policy circles. Data citations directly link scholarship and data, and as such provide a mechanism through which data can be discovered and accessed, scholarly use of data can be tracked, and the impact of data facilities can be identified. The interest in data citations is coming from many research stakeholders, including funders, policy makers, professional societies and their publication entities, research organizations, and individual researchers. Most of the efforts to date around data citations have focused on the challenges of assigning unique identifiers to digital data sets. While these challenges are significant, an additional challenge has gone relatively unaddressed, namely, the fact that data citation is not a common practice within scientific communities. This presentation will present findings from an interview study within the University Corporation for Atmospheric Research / National Center for Atmospheric Research (UCAR/NCAR). Through interviews with 14 scientists and engineers, we have found that there is little evidence that data citations have gained momentum as a common practice. Currently, data users acknowledge their use of particular data sets in either the research methods or acknowledgements sections of their papers, not as formal citations in a paper's bibliography. Data users are often 1) unaware that they can and should cite data sets, 2) unsure of how to cite data sets, and 3) lacking career motivations to forward data citations as a common activity. Data citation initiatives will have minimal impact on the scientific community if they do not address this practical inertia. Data users are a critical stakeholder in the data citation process. Their voice needs to be central to the data citation discussion. We will discuss how outreach efforts need to focus on raising the profile of data citations by informing scientists and administrators, being proactive in providing

  16. Charred Forests Increase Snow Albedo Decay: Watershed-Scale Implications of the Postfire Snow Albedo Effect

    NASA Astrophysics Data System (ADS)

    Gleason, K. E.; Nolin, A. W.

    2014-12-01

    Recent work shows that after a high severity forest fire, approximately 60% more solar radiation reaches the snow surface due to the reduction in canopy density. Also, significant amounts of black carbon (BC) particles and larger burned woody debris (BWD) are shed from standing charred trees, which concentrate on the snowpack, darken its surface, and reduce snow albedo by 50% during ablation. The postfire forest environment drives a substantial increase in net shortwave radiation at the snowpack surface, driving earlier and more rapid melt, however hydrologic models do not explicitly incorporate forest fire disturbance effects to snowpack dynamics. In this study we characterized, parameterized, and validated the postfire snow albedo effect: how the deposition and concentration of charred forest debris decreases snow albedo, increases snow albedo decay rates, and drives an earlier date of snow disappearance. For three study sites in the Oregon High Cascade Mountains, a 2-yr old burned forest, a 10-yr burned forest, and a nearby unburned forest, we used a suite of empirical data to characterize the magnitude and duration of the postfire effect to snow albedo decay. For WY 2012, WY2013, and WY2014 we conducted spectral albedo measurements, snow surface sampling, in-situ snow and meteorological monitoring, and snow energy balance modeling. From these data we developed a new parameterization which represents the postfire effect to snow albedo decay as a function of days-since-snowfall. We validated our parameterization using a physically-based, spatially-distributed snow accumulation and melt model, in-situ snow monitoring, net snowpack radiation, and remote sensing data. We modeled snow dynamics across the extent of all burned area in the headwaters of the McKenzie River Basin and validated the watershed-scale implications of the postfire snow albedo effect using in-situ micrometeorological and remote sensing data. This research quantified the watershed scale postfire

  17. Effects of moment of inertia on restricted motion swing speed.

    PubMed

    Schorah, David; Choppin, Simon; James, David

    2015-06-01

    In many sports, the maximum swing speed of a racket, club, or bat is a key performance parameter. Previous research in multiple sports supports the hypothesis of an inverse association between the swing speed and moment of inertia of an implement. The aim of this study was to rigorously test and quantify this relationship using a restricted swinging motion. Eight visually identical rods with a common mass but variable moment of inertia were manufactured. Motion capture technology was used to record eight participants' maximal effort swings with the rods. Strict exclusion criteria were applied to data that did not adhere to the prescribed movement pattern. The study found that for all participants, swing speed decreased with respect to moment of inertia according to a power relationship. However, in contrast to previous studies, the rate of decrease varied from participant to participant. With further analysis it was found that participants performed more consistently at the higher end of the moment of inertia range tested. The results support the inverse association between swing speed and moment of inertia but only for higher moment of inertia implements. PMID:25895860

  18. Instrument for measuring moment of inertia with high precision

    NASA Astrophysics Data System (ADS)

    Zheng, Yongjun; Lin, Min; Guo, Bin

    2010-08-01

    Accurate calculation of the moment of inertia of an irregular body is made difficult by the large number of quantities. A popular method is to use a trifilar suspension system to measure the period of oscillation of the body in the horizontal plane. In this paper, an instrument for measuring the moment of inertia based on trifilar pendulum is designed; some sources of error are discussed; three metal disks with known moments of inertia are used to calibrate the instrument, the other metal disks with known moments of inertia are used to test the accuracy of the instrument. The results are consistent when compared with calculated moment of inertia of the metal disks. In addition, the instrument could be used to measure the moment of inertia of other irregular objects. The period of oscillation is acquired by the capture mode of MSP430 microprocessor, the mass is obtained by the Electronic Balance and the data is transferred to the MSP430 via serial port.

  19. Hysteretic transitions in the Kuramoto model with inertia

    NASA Astrophysics Data System (ADS)

    Torcini, Alessandro; Olmi, Simona; Navas, Adrian; Boccaletti, Stefano

    2015-03-01

    We report finite size numerical investigations and mean field analysis of a Kuramoto model with inertia for fully coupled and diluted systems. In particular, we examine the transition from incoherence to coherence for increasingly large system size and inertia. For sufficiently large inertia the transition is hysteretic and within the hysteretic region clusters of locked oscillators of various sizes and different levels of synchronization coexist. A modification of the mean field theory developed by Tanaka, Lichtenberg, and Oishi allows to derive the synchronization curve associated to each of these clusters. We have also investigated numerically the limits of existence of the coherent and of the incoherent solutions. The minimal coupling required to observe the coherent state is largely independent of the system size and it saturates to a constant value already for moderately large inertia values. The incoherent state is observable up to a critical coupling whose value saturates for large inertia and for finite system sizes, while in the thermodinamic limit this critical value diverges proportionally to the mass. By increasing the inertia the transition becomes more complex, and the synchronization occurs via the emergence of clusters of coherently drifting oscillators. Financial support has been provided by the Italian Ministry of University and Research within the project CRISIS LAB PNR 2011-2013.

  20. ALBEDO PROPERTIES OF MAIN BELT ASTEROIDS BASED ON THE ALL-SKY SURVEY OF THE INFRARED ASTRONOMICAL SATELLITE AKARI

    SciTech Connect

    Usui, Fumihiko; Hasegawa, Sunao; Matsuhara, Hideo; Kasuga, Toshihiro; Ishiguro, Masateru; Kuroda, Daisuke; Mueller, Thomas G.; Ootsubo, Takafumi

    2013-01-01

    We present an analysis of the albedo properties of main belt asteroids (MBAs) detected by the All-Sky Survey of the infrared astronomical satellite AKARI. The characteristics of 5120 asteroids detected by the survey, including their sizes and albedos, were cataloged in the Asteroid Catalog Using AKARI (AcuA). Size and albedo measurements were based on the standard thermal model, using inputs of infrared fluxes and absolute magnitudes measured at optical wavelengths. MBAs, which account for 4722 of the 5120 AcuA asteroids, have semimajor axes of 2.06-3.27 AU, except for the near-Earth asteroids. AcuA provides a complete data set of all MBAs brighter than the absolute magnitude of H < 10.3, which corresponds to the diameter of d > 20 km. We confirmed that the albedo distribution of the MBAs is strongly bimodal as was already known from the past observations, and that the bimodal distribution occurs not only in the total population, but also within inner, middle, and outer regions of the main belt. The bimodal distribution in each group consists of low-albedo components in C-type asteroids and high-albedo components in S-type asteroids. We found that the small asteroids have much more variety in albedo than the large asteroids. In spite of the albedo transition process like space weathering, the heliocentric distribution of the mean albedo of asteroids in each taxonomic type is nearly flat. The mean albedo of the total, on the other hand, gradually decreases with an increase in semimajor axis. This can be explained by the compositional ratio of taxonomic types; that is, the proportion of dark asteroids such as C- and D-types increases, while that of bright asteroids such as S-type decreases, with increasing heliocentric distance. The heliocentric distributions of X-subclasses: E-, M-, and P-types, which can be divided based on albedo values, are also examined. P-types, which are the major component in X-types, are distributed throughout the main belt regions, and the

  1. Constraining Albedo and Composition of Four Potentially-Hazardous Asteroids via Near-IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Reddy, Vishnu; Gaffey, M.

    2009-09-01

    Near-infrared spectroscopic observations of potentially-hazardous asteroids 2005 RC34, (90403) 2003 YE45, (185851) 2000 DP107, and 2008 QS11 were obtained remotely using the SpeX instrument on NASA IRTF on Mauna Kea, Hawai'i. All data were reduced using IRAF and the PC-based SpecPR spectral processing program. Isolation of the Band I and II absorption features and calculation of band area ratios were accomplished using SpecPR. Albedo was estimated using STM based thermal modeling program, Thermflx. 2005 RC34 spectrum shows a weak inflection at 0.90±0.01 µm(<10%) with no thermal emission beyond 2.0 µm. The lack of thermal emission helps constrain the lower limit albedo of the object to be greater than or equal to 15±1%. Spectrum of 2003 YE45 shows a moderate absorption feature with a minimum at 1.0±0.1 µm (depth 20-25%) and a relatively flat spectrum beyond 1.4 µm. No thermal excess can be detected beyond 2.0 µm, which permits us to conservatively constrain the lower limit albedo to be greater than or equal to 5±1%. 2000 DP107 spectrum shows a moderately deep feature at 0.96±0.01 µm with sharp rise in reflectance beyond 2.0 µm due to thermal emission, which gives an estimated albedo of 2±1%. 2008 QS11 spectrum has a weak feature (band depth 8%) at 0.98±0.01 µm with a steep reddish slope and sharp rise in reflectance beyond 2.0 µm due to thermal emission. The measured thermal excess at 2.4 µm is 11%, which results in an estimated albedo of 5.5±1 %. Preliminary compositional analysis suggests that 2000 DP107 is a relatively dark object analogous to carbonaceous chondrites, 2005 RC34 belongs to taxonomic type E similar to aubrites or low-Fe pyroxene. 2003 YE45's surface is dominated by olivine and 2008 QS11 is similar to impact shock blackened chondrites. This research was supported by NASA NEOO Program Grants NNG04GI17G and NNX07AL29G.

  2. Baring high-albedo soils by overgrazing: a hypothesized desertification mechanism.

    PubMed

    Otterman, J

    1974-11-01

    Observations are reported of high-albedo soils denuded by overgrazing which appear bright, in high contrast to regions covered by natural vegetation. Measurements and modeling show that the denuded surfaces are cooler, when compared under sunlit conditions. This observed "thermal depression" eflect should, on theoretical grounds, result in a decreased lifting of air necessary for cloud formation and precipitation, and thus lead to regional climatic desertification. PMID:17790382

  3. Baring high-albedo soils by overgrazing - A hypothesized desertification mechanism

    NASA Technical Reports Server (NTRS)

    Otterman, J.

    1974-01-01

    Observations are reported of high-albedo soils denuded by overgrazing which appear bright, in high contrast to regions covered by natural vegetation. Measurements and modeling show that the denuded surfaces are cooler, when compared under sunlit conditions. This observed 'thermal depression' effect should, on theoretical grounds, result in a decreased lifting of air necessary for cloud formation and precipitation, and thus lead to regional climatic desertification.

  4. Estimating the broadband longwave emissivity of global bare soil from the MODIS shortwave albedo product

    NASA Astrophysics Data System (ADS)

    Cheng, Jie; Liang, Shunlin

    2014-01-01

    A constant land surface longwave emissivity value, or very simple parameterization, has been adopted by current land surface models because of a current lack of reliable observations. Of all the various Earth surface types, bare soil has the highest variations in broadband emissivity (BBE). We propose here a new algorithm to estimate BBE in the 8-13.5 µm spectral range based on the Moderate Resolution Imaging Spectrometer (MODIS) albedo product for bare soil. This algorithm takes advantage of both Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) longwave emissivity and MODIS shortwave albedo products, as well as the established linear relationship between ASTER BBE and seven MODIS spectral albedos for bare soil. In order to mitigate step discontinuities in the global land surface BBE product, a transition zone was established and the BBE estimation method was also provided. Three linear formulae were derived for bare soil and transition zones, respectively. Given the accuracy of 0.01 for MODIS spectral albedo, the absolute accuracy of BBE retrieval is better than 0.017. The validation results obtained from the three field trials conducted in China and one field trial in western/southwestern U.S. indicated that the average difference between the estimated BBE and the measured BBE was 0.016. We have introduced a new strategy to generate global land surface BBE using MODIS data. This strategy was used to generate global 8 day 1 km land surface BBE products from 2000 through 2010.

  5. The size and albedo of the Kuiper-belt object (20000) Varuna.

    PubMed

    Jewitt, D; Aussel, H; Evans, A

    2001-05-24

    Observations over the last decade have revealed the existence of a large number of bodies orbiting the Sun beyond Neptune. Known as the Kuiper-belt objects (KBOs), they are believed to be formed in the outer reaches of the protoplanetary disk around the young Sun, and have been little altered since then. They are probably the source of short-period comets. The KBOs are, however, difficult objects to study because of their distance from earth, so even basic physical properties such as their sizes and albedos remain unknown. Previous size estimates came from assuming an albedo with the canonical value being 0.04. Here we report simultaneous measurements of the thermal emission and reflected optical light of the bright KBO (20000) Varuna, which allow us to determine independently both the size and the albedo. Varuna has an equivalent circular diameter of D = 900+129-145 km and a red geometric albedo of pR = 0.070+0.030-0.017. Its surface is darker than Pluto's, suggesting that it is largely devoid of fresh ice, but brighter than previously assumed for KBOs. PMID:11373669

  6. Seasonal flows on dark martian slopes, thermal condition for liquescence of salts

    NASA Astrophysics Data System (ADS)

    Kossacki, Konrad J.; Markiewicz, Wojciech J.

    2014-05-01

    RSLs are narrow, dark albedo features on relatively steep slopes that appear during warm seasons and fade in the cold ones. So far they have only been observed in mid-latitudes where surface temperature is too high, periodically exceeding 300 K, for the presence of shallow ground ice. We attempt to determine what conditions are needed for the liquescence of salt to occur exactly when the RSLs are observed. If the eutectic temperature is exceeded, and humidity is high enough, salts may produce liquid brines through absorption of water vapor and liquescence. We calculate regolith temperature as a function of time and depth, for different macroscopic distributions of salt, for two different microphysical models of the distribution of salt on the regolith grains. Model parameters which are varied include surface albedo, thermal inertia of the dry regolith, the depths at which salt is present, and the salt content. We find that it is possible, for liquescence of magnesium perchlorate to occur where and when RSLs have been observed, but only within a very narrow range of parameters.

  7. Physical properties of transneptunian objects, Centaurs, and Trojans from thermal observations

    NASA Astrophysics Data System (ADS)

    Mueller, M.

    2014-07-01

    The most productive way to measure the size and albedo of small bodies throughout the Solar System is through studies of their thermal emission. This is complicated for the cold bodies in the outer Solar System, whose thermal emission peaks at wavelengths for which the Earth's atmosphere is opaque. While the relatively warm Trojans are marginally accessible from the ground in the Q band, the sizes of only a handful of transneptunian objects (TNOs) and Centaurs were known before Spitzer was launched in 2003. Spitzer/MIPS photometry at wavelengths of 24 and 70 microns allowed size and albedo of tens of TNOs and Centaurs to be measured. Herschel (operational in 2009--2013) allowed photometry of a total of ˜140 TNOs at wavelengths between 70 and 500 microns using PACS and SPIRE, chiefly in the framework of the Key Programme ``TNOs are Cool!''. I will present selected results from these surveys and discuss their implications on our knowledge of the origin and evolution of the Solar System, as evidenced by its coldest members. Of particular interest are the sizes of binary systems. Where their masses are known from spatially resolved observations, diameter measurements allow the bulk mass density to be determined, providing a unique probe of the object's interior. In the past few years, we have witnessed a remarkable increase in the number of successfully observed stellar occultations by TNOs and other small bodies. They provide an elegant, model-independent, and accurate way of measuring projected TNO dimensions at the time of the event and at the location of the observer(s). Even satellites or ring systems can be detected this way. However, predictable occultations are rare events and will likely stay infrequent, even in the post-Gaia era. Studies of the ensemble properties of the transneptunian populations will continue to rely on thermal observations. Reliable thermal modeling requires some knowledge of the target's temperature. Optimally, this is obtained through

  8. RECTIFIED ASTEROID ALBEDOS AND DIAMETERS FROM IRAS AND MSX PHOTOMETRY CATALOGS

    SciTech Connect

    Ryan, Erin Lee; Woodward, Charles E. E-mail: chelsea@astro.umn.ed

    2010-10-15

    Rectified diameters and albedo estimates of 1517 main-belt asteroids selected from IRAS and the Mid-Course Space Experiment asteroid photometry catalogs are derived from updated infrared thermal models, the Standard Thermal Model and the Near-Earth Asteroid Thermal Model (NEATM), and Monte Carlo simulations, using new Minor Planet Center compilations of absolute magnitudes (H values) constrained by occultation- and radar-derived parameters. The NEATM approach produces a more robust estimate of albedos and diameters, yielding albedos of p{sub v} (NEATM mean) =0.081 {+-} 0.064. The asteroid beaming parameter ({eta}) for the selected asteroids has a mean value of 1.07 {+-} 0.27, and the smooth distribution of {eta} suggests that this parameter is independent of asteroid properties such as composition. No trends in {eta} due to size-dependent rotation rates are evident. Comparison of derived values of {eta} as a function of taxonomic type indicates that the beaming parameter values for S- and C-type asteroids are identical within the standard deviation of the population of beaming parameters.

  9. Constraining Albedo And Composition Of Potentially-Hazardous Asteroids 2004 XP14 And (100085) 1992 UY4 Via Near-IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Reddy, Vishnu; Gaffey, M. J.; Hardersen, P. S.; Abell, P. A.; Kumar, S.

    2006-09-01

    Near-infrared spectroscopic observations of potentially-hazardous asteroids (PHAs) 2004 XP14 were obtained on July 5, 2006 and 1992 UY4 on July 31, 2005, using the SpeX instrument at NASA IRTF on Mauna Kea, Hawai'i. Near-IR spectrum of 2004 XP14 has a neutral slope and shows no detectable absorption features. Given its heliocentric distance (1.02 A.U.), a sharp rise in reflectance beyond 2.0-µm due to thermal emission would be expected if the PHA was a low albedo object. No such excess was detected in the spectrum of 2004 XP14 which establishes a lower limit on the albedo. Using Standard Thermal Model and methods developed by Abell (2003), we estimate the lower limit on the albedo to be 20%. A high albedo (>20%) featureless spectrum suggests that 2004 XP14 belongs to the M- or E-type taxonomic class. 1992 UY4 spectrum also shows no detectable absorption features but exhibits a sharp rise in reflectance beyond 2.0-µm due to thermal emission at its heliocentric distance (1.08 A.U.) at the time of observation. Using the same methods, we estimate the albedo from thermal emission to be 6.0±1; %. Based on albedo, the estimated diameter (Flower & Chillemi, 1992) is 1.8±0.2 km, given the limitations in the STM model. We suggest that 1992 UY4 is a dark object with significant low-albedo absorbing species like carbon in its surface assemblage, given its featureless spectrum and 6.0±1; % albedo. The authors would like to thank NASA IRTF for providing Target of Opportunity observing time for observing 2004 XP14 flyby. This research was supported by NASA Near-Earth Objects Observations Program grant NNG04GI17G.

  10. Water Ice Albedo Variations on the Martian Northern Polar Cap

    NASA Technical Reports Server (NTRS)

    Hale, A. S.; Bass, D. S.; Tamppari, L. K.

    2003-01-01

    The Viking Orbiters determined that the surface of Mars northern residual cap is water ice. Many researchers have related observed atmospheric water vapor abundances to seasonal exchange between reservoirs such as the polar caps, but the extent to which the exchange between the surface and the atmosphere remains uncertain. Early studies of the ice coverage and albedo of the northern residual Martian polar cap using Mariner 9 and Viking images reported that there were substantial internannual differences in ice deposition on the polar cap, a result which suggested a highly variable Martian climate. However, some of the data used in these studies were obtained at differing values of heliocentric solar longitude (L(sub s)). Reevaluation of this dataset indicated that the residual cap undergoes seasonal brightening throughout the summer, and indicated that this process repeats from year to year. In this study we continue to compare Mariner 9 and Viking Orbiter imaging observations and thermal data of the north residual polar cap to data acquired with Mars Global Surveyor s Mars Orbiter Camera (MOC) instrument. In the current study, our goal is to examine all released data from MGS MOC in the northern summer season, along with applicable TES data in order to better understand the albedo variations in the northern summer and their implications on water transport. To date, work has focused primarily on the MOC dataset. In 1999, data acquisition of the northern polar regions began at L(sub s) = 107, although there was little north polar data acquired from L(sub s)= 107 to L(sub s) = 109. We examined a total of 409 images from L(sub s) = 107 to L(sub s)=148. We have also examined data from 2000 from L(sub s)= 93 to L(sub s)= 110; additional progress is ongoing. Here we present a progress report of our observations, and continue to determine their implications for the Martian water cycle.

  11. Global color and albedo variations on Io

    NASA Technical Reports Server (NTRS)

    Mcewen, Alfred S.

    1988-01-01

    The present Voyager imaging data multispectral mosaics of Io include global mosaics from each of the Voyager 1 and 2 data sets and a high-resolution mosaic of the region centered on the Ra Patera volcano. The constancy of the disk-integrated color and albedo of Io over recent decades despite volcanic activity may be due to the regular occurrence of large Pele-type plumes with relatively dark, red deposits. Io's intrinsic spectral variability involves continuous variation among three major spectral end members. Attention is given to the mapping of the data into five spectral units for the purposes of comparison with laboratory measurements of Io surface material candidates.

  12. Albedo and transmittance of inhomogeneous stratus clouds

    SciTech Connect

    Zuev, V.E.; Kasyanov, E.I.; Titov, G.A.

    1996-04-01

    A highly important topic is the study of the relationship between the statistical parameters of optical and radiative charactertistics of inhomogeneous stratus clouds. This is important because the radiation codes of general circulation models need improvement, and it is important for geophysical information. A cascade model has been developed at the Goddard Space Flight Center to treat stratocumulus clouds with the simplest geometry and horizontal fluctuations of the liquid water path (optical thickness). The model evaluates the strength with which the stochastic geometry of clouds influences the statistical characteristics of albedo and the trnasmittance of solar radiation.

  13. Impact of Atmospheric Albedo on Amazon Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Lopes, A. V.; Thompson, S. E.; Dracup, J. A.

    2013-12-01

    The vulnerability of the Amazon region to climate and anthropogenic driven disturbances has been the subject of extensive research efforts, given its importance in the global and regional climate and ecologic systems. The evaluation of such vulnerabilities requires the proper understanding of physical mechanisms controlling water and energy balances and how the disturbances change them. Among those mechanisms, the effects of atmospheric albedo on evapotranspiration have not been fully explored yet and are explored in this study. Evapotranspiration in the Amazon is sustained at high levels across all seasons and represents a large fraction of water and energy surface budgets. In this study, statistical analysis of data from four flux towers installed at Amazon primary forest sites was employed to quantify the impact of atmospheric albedo, mostly resulted from cloudiness, on evapotranspiration and to compare it to the effect of water limitation. Firstly, the difference in eddy-flux derived evapotranspiration at the flux towers under rainy and non-rainy antecedent conditions was tested for significance. Secondly, the same statistical comparison was performed under cloudy and clear sky conditions at hourly and daily time scales, using the reduction in incoming solar radiation as an indicator of cloudiness. Finally, the sensitivity of seasonal evapotranspiration totals to atmospheric albedo resulted from rainfall patterns is evaluated. That was done by sampling daily evapotranspiration estimates from empirical probability distribution functions conditioned to rainfall occurrence and then varying the number of dry days in each season. It was found that light limitation is much more important than water limitation in the Amazon, resulting in up to 43% reduction in daily evapotranspiration. Also, this effect varies by location and by season, the largest impact being in wet season, from December do January. Moreover, seasonal evapotranspiration totals were found to be

  14. Albedo maps of Pluto and Charon - Initial mutual event results

    NASA Technical Reports Server (NTRS)

    Buie, Marc W.; Tholen, David J.; Horne, Keith

    1992-01-01

    By applying the technique of maximum entropy image reconstruction to invert observed lightcurves, surface maps of single-scattering albedo are obtained for the surfaces of Pluto and Charon from 1954 to 1986. The albedo features of the surface of Pluto are similar to those of the Buie and Tholen (1989) spot model maps; a south polar cap is evident. The map of Charon is somewhat darker, with single-scattering albedos as low as 0.03.

  15. Correlation of Far Ultraviolet Lunar Albedo with Solar Activity

    NASA Technical Reports Server (NTRS)

    Maddox, Will; Spann, James F.; Germany, Glynn

    2004-01-01

    We present a correlative analysis between the variability of the lunar albedo in the far ultraviolet wavelength range (130- 190 nm) and various solar activity indices for a two-week period. We also report lunar albedo measurements in four separate wavelength ranges, corresponding to four filters on the Polar Ultraviolet Imager. To our knowledge this is the first reported long term measurements of the lunar albedo in this wavelength range.

  16. The Near-Earth Encounter of Asteroid 308635 (2005 YU55): Thermal IR Observations

    NASA Astrophysics Data System (ADS)

    Lim, Lucy F.; Emery, J. P.; Moskovitz, N. A.; Busch, M. W.; Yang, B.; Granvik, M.

    2012-10-01

    The near-Earth approach (0.00217 AU, or 0.845 lunar distances) of the C-type asteroid 308635 (2005 YU55) in November 2011 presented a rare opportunity for detailed observations of a low-albedo NEA in this size range. As part of a multi-telescope campaign to measure visible and infrared spectra and photometry, we obtained mid-infrared ( 8 to 22 micron) photometry and spectroscopy of 2005 YU55 using Michelle [1] on the Gemini North telescope on UT November 9 and 10, 2011. An extensive radar campaign [2] together with optical lightcurves [3,4] established the rotation state of YU55. In addition, the radar imaging resulted in a shape model for the asteroid, detection of numerous boulders on its surface, and a preliminary estimate of its equatorial diameter at 380 +/- 20 m. In a preliminary analysis, applying the radar and lightcurve-derived parameters to a rough-surface thermophysical model fit to the Gemini/Michelle thermal emission photometry results in a thermal inertia range of approximately 500 to 1500 J m-2 s-1/2 K-1, with the low-thermal-inertia solution corresponding to the small end of the radar size range and vice versa. Updates to these results will be presented and modeling of the thermal contribution to the measured near-infrared spectra from Palomar/Triplespec and IRTF/SpeX will also be discussed. The authors gratefully acknowledge the assistance of observatory staff and the support of the NASA NEOO program (LFL and JPE), the Carnegie fellowship (NAM), and NASA AES, NSF, and the NRAO Jansky Fellowship (MWB). [1] De Buizer, J. and R. Fisher, Proc. Hris (2005), pp. 84-87. [2] Busch, M.W. et al., ACM (2012), abstract #6179. [3] Warner, B., MPBull 39 (2), 84 [4] Pravec, P.

  17. A Novel Flexible Inertia Weight Particle Swarm Optimization Algorithm.

    PubMed

    Amoshahy, Mohammad Javad; Shamsi, Mousa; Sedaaghi, Mohammad Hossein

    2016-01-01

    Particle swarm optimization (PSO) is an evolutionary computing method based on intelligent collective behavior of some animals. It is easy to implement and there are few parameters to adjust. The performance of PSO algorithm depends greatly on the appropriate parameter selection strategies for fine tuning its parameters. Inertia weight (IW) is one of PSO's parameters used to bring about a balance between the exploration and exploitation characteristics of PSO. This paper proposes a new nonlinear strategy for selecting inertia weight which is named Flexible Exponential Inertia Weight (FEIW) strategy because according to each problem we can construct an increasing or decreasing inertia weight strategy with suitable parameters selection. The efficacy and efficiency of PSO algorithm with FEIW strategy (FEPSO) is validated on a suite of benchmark problems with different dimensions. Also FEIW is compared with best time-varying, adaptive, constant and random inertia weights. Experimental results and statistical analysis prove that FEIW improves the search performance in terms of solution quality as well as convergence rate. PMID:27560945

  18. Inertia and Double Bending of Light from Equivalence

    NASA Technical Reports Server (NTRS)

    Shuler, Robert L., Jr.

    2010-01-01

    Careful examination of light paths in an accelerated reference frame, with use of Special Relativity, can account fully for the observed bending of light in a gravitational field, not just half of it as reported in 1911. This analysis also leads to a Machian formulation of inertia similar to the one proposed by Einstein in 1912 and later derived from gravitational field equations in Minkowsky Space by Sciama in 1953. There is a clear inference from equivalence that there is some type of inertial mass increase in a gravitational field. It is the purpose of the current paper to suggest that equivalence provides a more complete picture of gravitational effects than previously thought, correctly predicting full light bending, and that since the theory of inertia is derivable from equivalence, any theory based on equivalence must take account of it. Einstein himself clearly was not satisfied with the status of inertia in GRT, as our quotes have shown. Many have tried to account for inertia and met with less than success, for example Davidson s integration of Sciama s inertia into GRT but only for a steady state cosmology [10], and the Machian gravity theory of Brans and Dicke [11]. Yet Mach s idea hasn t gone away, and now it seems that it cannot go away without also disposing of equivalence.

  19. A Novel Flexible Inertia Weight Particle Swarm Optimization Algorithm

    PubMed Central

    Shamsi, Mousa; Sedaaghi, Mohammad Hossein

    2016-01-01

    Particle swarm optimization (PSO) is an evolutionary computing method based on intelligent collective behavior of some animals. It is easy to implement and there are few parameters to adjust. The performance of PSO algorithm depends greatly on the appropriate parameter selection strategies for fine tuning its parameters. Inertia weight (IW) is one of PSO’s parameters used to bring about a balance between the exploration and exploitation characteristics of PSO. This paper proposes a new nonlinear strategy for selecting inertia weight which is named Flexible Exponential Inertia Weight (FEIW) strategy because according to each problem we can construct an increasing or decreasing inertia weight strategy with suitable parameters selection. The efficacy and efficiency of PSO algorithm with FEIW strategy (FEPSO) is validated on a suite of benchmark problems with different dimensions. Also FEIW is compared with best time-varying, adaptive, constant and random inertia weights. Experimental results and statistical analysis prove that FEIW improves the search performance in terms of solution quality as well as convergence rate. PMID:27560945

  20. Impact of weather events on Arctic sea ice albedo evolution

    NASA Astrophysics Data System (ADS)

    Arntsen, A. E.; Perovich, D. K.; Polashenski, C.; Stwertka, C.

    2015-12-01

    Arctic sea ice undergoes a seasonal evolution from cold snow-covered ice to melting snow to bare ice with melt ponds. Associated with this physical evolution is a decrease in the albedo of the ice cover. While the change in albedo is often considered as a steady seasonal decrease, weather events during melt, such as rain or snow, can impact the albedo evolution. Measurements on first year ice in the Chukchi Sea showed a decrease in visible albedo to 0.77 during the onset of melt. New snow from 4 - 6 June halted melting and increased the visible albedo to 0.87. It took 12 days for the albedo to decrease to levels prior to the snowfall. Incident solar radiation is large in June and thus a change in albedo has a large impact on the surface heat budget. The snowfall increased the albedo by 0.1 and reduced the absorbed sunlight from 5 June to 17 June by approximately 32 MJ m-2. The total impact of the snowfall will be even greater, since the delay in albedo reduction will be propagated throughout the entire summer. A rain event would have the opposite impact, increasing solar heat input and accelerating melting. Snow or rain in May or June can impact the summer melt cycle of Arctic sea ice.

  1. THE ALBEDO-COLOR DIVERSITY OF TRANSNEPTUNIAN OBJECTS

    SciTech Connect

    Lacerda, Pedro; Rengel, Miriam; Fornasier, Sonia; Lellouch, Emmanuel; Delsanti, Audrey; Kiss, Csaba; Vilenius, Esa; Müller, Thomas; Santos-Sanz, Pablo; Duffard, René; Guilbert-Lepoutre, Aurélie

    2014-09-20

    We analyze albedo data obtained using the Herschel Space Observatory that reveal the existence of two distinct types of surface among midsized trans-Neptunian objects. A color-albedo diagram shows two large clusters of objects, one redder and higher albedo and another darker and more neutrally colored. Crucially, all objects in our sample located in dynamically stable orbits within the classical Kuiper Belt region and beyond are confined to the bright red group, implying a compositional link. Those objects are believed to have formed further from the Sun than the dark neutral bodies. This color-albedo separation is evidence for a compositional discontinuity in the young solar system.

  2. The first cosmic ray albedo proton map of the Moon

    NASA Astrophysics Data System (ADS)

    Wilson, Jody K.; Spence, Harlan E.; Kasper, Justin; Golightly, Michael; Bern Blake, J.; Mazur, Joe E.; Townsend, Lawrence W.; Case, Anthony W.; Dixon Looper, Mark; Zeitlin, Cary; Schwadron, Nathan A.

    2012-06-01

    Neutrons emitted from the Moon are produced by the impact of galactic cosmic rays (GCRs) within the regolith. GCRs are high-energy particles capable of smashing atomic nuclei in the lunar regolith and producing a shower of energetic protons, neutrons and other subatomic particles. Secondary particles that are ejected out of the regolith become “albedo” particles. The neutron albedo has been used to study the hydrogen content of the lunar regolith, which motivates our study of albedo protons. In principle, the albedo protons should vary as a function of the input GCR source and possibly as a result of surface composition and properties. During the LRO mission, the total detection rate of albedo protons between 60 MeV and 150 MeV has been declining since 2009 in parallel with the decline in the galactic cosmic ray flux, which validates the concept of an albedo proton source. On the other hand, the average yield of albedo protons has been increasing as the galactic cosmic ray spectrum has been hardening, consistent with a disproportionately stronger modulation of lower energy GCRs as solar activity increases. We construct the first map of the normalized albedo proton emission rate from the lunar surface to look for any albedo variation that correlates with surface features. The map is consistent with a spatially uniform albedo proton yield to within statistical uncertainties.

  3. Enhancement of the MODIS Daily Snow Albedo Product

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Schaaf, Crystal B.; Wang, Zhuosen; Riggs, George A.

    2009-01-01

    The MODIS daily snow albedo product is a data layer in the MOD10A1 snow-cover product that includes snow-covered area and fractional snow cover as well as quality information and other metadata. It was developed to augment the MODIS BRDF/Albedo algorithm (MCD43) that provides 16-day maps of albedo globally at 500-m resolution. But many modelers require daily snow albedo, especially during the snowmelt season when the snow albedo is changing rapidly. Many models have an unrealistic snow albedo feedback in both estimated albedo and change in albedo over the seasonal cycle context, Rapid changes in snow cover extent or brightness challenge the MCD43 algorithm; over a 16-day period, MCD43 determines whether the majority of clear observations was snow-covered or snow-free then only calculates albedo for the majority condition. Thus changes in snow albedo and snow cover are not portrayed accurately during times of rapid change, therefore the current MCD43 product is not ideal for snow work. The MODIS daily snow albedo from the MOD10 product provides more frequent, though less robust maps for pixels defined as "snow" by the MODIS snow-cover algorithm. Though useful, the daily snow albedo product can be improved using a daily version of the MCD43 product as described in this paper. There are important limitations to the MOD10A1 daily snow albedo product, some of which can be mitigated. Utilizing the appropriate per-pixel Bidirectional Reflectance Distribution Functions (BRDFs) can be problematic, and correction for anisotropic scattering must be included. The BRDF describes how the reflectance varies with view and illumination geometry. Also, narrow-to-broadband conversion specific for snow on different surfaces must be calculated and this can be difficult. In consideration of these limitations of MOD10A1, we are planning to improve the daily snow albedo algorithm by coupling the periodic per-pixel snow albedo from MCD43, with daily surface ref|outanoom, In this paper, we

  4. Thermal infrared observations and thermophysical characterization of OSIRIS-REx target asteroid (101955) Bennu

    NASA Astrophysics Data System (ADS)

    Emery, J. P.; Fernández, Y. R.; Kelley, M. S. P.; Warden (nèe Crane), K. T.; Hergenrother, C.; Lauretta, D. S.; Drake, M. J.; Campins, H.; Ziffer, J.

    2014-05-01

    Near-Earth Asteroids (NEAs) have garnered ever increasing attention over the past few years due to the insights they offer into Solar System formation and evolution, the potential hazard they pose, and their accessibility for both robotic and human spaceflight missions. Among the NEAs, carbonaceous asteroids hold particular interest because they may contain clues to how the Earth got its supplies of water and organic materials, and because none has yet been studied in detail by spacecraft. (101955) Bennu is special among NEAs in that it will not only be visited by a spacecraft, but the OSIRIS-REx mission will also return a sample of Bennu’s regolith to Earth for detailed laboratory study. This paper presents analysis of thermal infrared photometry and spectroscopy that test the hypotheses that Bennu is carbonaceous and that its surface is covered in fine-grained (sub-cm) regolith. The Spitzer Space Telescope observed Bennu in 2007, using the Infrared Spectrograph (IRS) to obtain spectra over the wavelength range 5.2-38 μm and images at 16 and 22 μm at 10 different longitudes, as well as the Infrared Array Camera (IRAC) to image Bennu at 3.6, 4.5, 5.8, and 8.0 μm, also at 10 different longitudes. Thermophysical analysis, assuming a spherical body with the known rotation period and spin-pole orientation, returns an effective diameter of 484 ± 10 m, in agreement with the effective diameter calculated from the radar shape model at the orientation of the Spitzer observations (492 ± 20 m, Nolan, M.C., Magri, C., Howell, E.S., Benner, L.A.M., Giorgini, J.D., Hergenrother, C.W., Hudson, R.S., Lauretta, D.S., Margo, J.-L., Ostro, S.J., Scheeres, D.J. [2013]. Icarus 226, 629-640) and a visible geometric albedo of 0.046 ± 0.005 (using Hv = 20.51, Hergenrother, C.W. et al. [2013]. Icarus 226, 663-670). Including the radar shape model in the thermal analysis, and taking surface roughness into account, yields a disk-averaged thermal inertia of 310 ± 70 J m-2 K-1 s-1

  5. Entrainment, Drizzle, and Stratocumulus Cloud Albedo

    NASA Technical Reports Server (NTRS)

    Ackerman, A. S.; Kirkpatrick, M. P.; Stevens, D. E.; Toon, O. B.

    2004-01-01

    Globally averaged cloud changes from GCMs on average show a doubling of the Twomey effect, which is the change in cloud albedo with respect to changes in droplet concentrations for fixed cloud water and droplet dispersion. In contrast, ship-track measurements show a much more modest amplification of the Twomey effect, suggesting that the GCMs are exaggerating the indirect aerosol effect. We have run large-eddy simulations with bin microphysics of marine stratocumulus from multiple field campaigns, and find that the large-eddy simulations are in much better agreement with the ship-track measurements. The inversion strength over N. Pacific stratocumulus (as measured during DYCOMS-II) is generally much stronger than over N. Atlantic stratocumulus (as measured during ASTEX), and we have found that the response of cloud water to increasing droplet concentration changes sign as the inversion strengthens. For the different environmental conditions, we will show the overall response of cloud albedo to droplet concentrations, and decompose the response into its contributing factors of changes in cloud water, droplet dispersion, and horizontal inhomogeneity.

  6. Lithological and textural controls on radar and diurnal thermal signatures of weathered volcanic deposits, Lunar Crater region, Nevada

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.; Rivard, Benoit

    1992-01-01

    Radar backscatter intensity as measured by calibrated synthetic aperture radar (SAR) systems is primarily controlled by three factors: local incidence angle, wavelength-scale roughness, and dielectric permittivity of surface materials. Radar observations may be of limited use for geological investigations of surface composition, unless the relationships between lithology and the above characteristics can be adequately understood. In arid terrains, such as the Southwest U.S., weathering signatures (e.g. soil development, fracturing, debris grain size and shape, and hill slope characteristics) are controlled to some extent by lithologic characteristics of the parent bedrock. These textural features of outcrops and their associated debris will affect radar backscatter to varying degrees, and the multiple-wavelength capability of the JPL Airborne SAR (AIRSAR) system allows sampling of textures at three distinct scales. Diurnal temperature excursions of geologic surfaces are controlled primarily by the thermal inertia of surface materials, which is a measure of the resistance of a material to a change in temperature. Other influences include albedo, surface slopes affecting insolation, local meteorological conditions and surface emissivity at the relevant thermal wavelengths. To first order, thermal inertia variations on arid terrain surfaces result from grain size distribution and porosity differences, at scales ranging from micrometers to tens of meters. Diurnal thermal emission observations, such as those made by the JPL Thermal Infrared Multispectral Scanner (TIMS) airborne instrument, are thus influenced by geometric surface characteristics at scales comparable to those controlling radar backscatter. A preliminary report on a project involving a combination of field, laboratory and remote sensing observations of weathered felsic-to basaltic volcanic rock units exposed in the southern part of the Lunar Crater Volcanic Field, in the Pancake Range of central Nevada is

  7. Moment of inertia of liquid in a tank

    NASA Astrophysics Data System (ADS)

    Lee, Gyeong Joong

    2014-03-01

    In this study, the inertial properties of fully filled liquid in a tank were studied based on the potential theory. The analytic solution was obtained for the rectangular tank, and the numerical solutions using Green's 2nd identity were obtained for other shapes. The inertia of liquid behaves like solid in recti-linear acceleration. But under rotational acceleration, the moment of inertia of liquid becomes small compared to that of solid. The shapes of tank investigated in this study were ellipse, rectangle, hexagon, and octagon with various aspect ratios. The numerical solu¬tions were compared with analytic solution, and an ad hoc semi-analytical approximate formula is proposed herein and this formula gives very good predictions for the moment of inertia of the liquid in a tank of several different geometrical shapes. The results of this study will be useful in analyzing of the motion of LNG/LPG tanker, liquid cargo ship, and damaged ship.

  8. Gender in Science and Engineering Faculties: Demographic Inertia Revisited

    PubMed Central

    Thomas, Nicole R.; Poole, Daniel J.; Herbers, Joan M.

    2015-01-01

    The under-representation of women on faculties of science and engineering is ascribed in part to demographic inertia, which is the lag between retirement of current faculty and future hires. The assumption of demographic inertia implies that, given enough time, gender parity will be achieved. We examine that assumption via a semi-Markov model to predict the future faculty, with simulations that predict the convergence demographic state. Our model shows that existing practices that produce gender gaps in recruitment, retention, and career progression preclude eventual gender parity. Further, we examine sensitivity of the convergence state to current gender gaps to show that all sources of disparity across the entire faculty career must be erased to produce parity: we cannot blame demographic inertia. PMID:26488899

  9. Electron inertia effects on the planar plasma sheath problem

    SciTech Connect

    Duarte, V. N.; Clemente, R. A.

    2011-04-15

    The steady one-dimensional planar plasma sheath problem, originally considered by Tonks and Langmuir, is revisited. Assuming continuously generated free-falling ions and isothermal electrons and taking into account electron inertia, it is possible to describe the problem in terms of three coupled integro-differential equations that can be numerically integrated. The inclusion of electron inertia in the model allows us to obtain the value of the plasma floating potential as resulting from an electron density discontinuity at the walls, where the electrons attain sound velocity and the electric potential is continuous. Results from numerical computation are presented in terms of plots for densities, electric potential, and particles velocities. Comparison with results from literature, corresponding to electron Maxwell-Boltzmann distribution (neglecting electron inertia), is also shown.

  10. Temperature-dependent particle-number projected moment of inertia

    SciTech Connect

    Allal, N. H.; Fellah, M.; Benhamouda, N.; Oudih, M. R.

    2008-05-15

    Expressions of the parallel and perpendicular temperature-dependent particle-number projected nuclear moment of inertia have been established by means of a discrete projection method. They generalize that of the FTBCS method and are well adapted to numerical computation. The effects of particle-number fluctuations have been numerically studied for some even-even actinide nuclei by using the single-particle energies and eigenstates of a deformed Woods-Saxon mean field. It has been shown that the parallel moment of inertia is practically not modified by the use of the projection method. In contrast, the discrepancy between the projected and FTBCS perpendicular moment of inertia values may reach 5%. Moreover, the particle-number fluctuation effects vary not only as a function of the temperature but also as a function of the deformation for a given temperature. This is not the case for the system energy.

  11. Gender in Science and Engineering Faculties: Demographic Inertia Revisited.

    PubMed

    Thomas, Nicole R; Poole, Daniel J; Herbers, Joan M

    2015-01-01

    The under-representation of women on faculties of science and engineering is ascribed in part to demographic inertia, which is the lag between retirement of current faculty and future hires. The assumption of demographic inertia implies that, given enough time, gender parity will be achieved. We examine that assumption via a semi-Markov model to predict the future faculty, with simulations that predict the convergence demographic state. Our model shows that existing practices that produce gender gaps in recruitment, retention, and career progression preclude eventual gender parity. Further, we examine sensitivity of the convergence state to current gender gaps to show that all sources of disparity across the entire faculty career must be erased to produce parity: we cannot blame demographic inertia. PMID:26488899

  12. Frequency coverter PDFSV control based on inertia identification

    NASA Astrophysics Data System (ADS)

    Bai, Guochang; Qi, Xiaoye; Wang, Zhanlin

    2008-10-01

    Excitation current and torque current are decoupled through vector control in frequency converter, so the linear control method can be used in speed loop. Pseudo derivative feedback with sub-variable control (PDFSV) has excellent performance and easy to realize. Its control parameters are obtained through present equation which is related to inertia parameter. To the frequency converter system with parameter changes at extensive range, the PDFSV control with variable control coefficient is presented: to construct full-order state observer, to observe the speed error signal which contains error information on the moment of inertia and calculate control coefficient by presented equations, and feed forward the observed load. The simulation results show that the speed control response performance well when the moment of inertia and disturb load varied at extensive range.

  13. The Distribution of Geometric Albedos of Jupiter-Family Comets From SEPPCoN and Visible-Wavelength Photometry

    NASA Astrophysics Data System (ADS)

    Fernandez, Yanga R.; Weaver, Harold A.; Lisse, Casey M.; Meech, Karen Jean; Lowry, Stephen C.; Bauer, James M.; Fitzsimmons, Alan; Snodgrass, Colin

    2016-01-01

    Cometary nuclei are some of the least reflective natural objects in the Solar System, although the number of comets for which the reflectivity has heretofore actually been measured is small due to the difficulty of the requisite measurements. When no other information is present, it is common to assume a geometric albedo of 4%, and this is consistent with the limited number of known albedos. However the true average albedo, median albedo, and spread of the distribution are not well constrained. Knowing the ensemble properties of cometary albedos would aid in understanding the surface scattering properties as well as the interior thermal evolution and surface evolution of the population. We present here a preliminary estimate of the distribution of geometric albedos among the Jupiter-family comet (JFC) population. We make use of and build on the results of the Survey of Ensemble Physical Properties of Cometary Nuclei (SEPPCoN), in which we obtained new and independent estimates of the radii of 89 JFCs [1,2]. We will present our preliminary albedo estimates for ~50 JFC nuclei (by far the most ever obtained), and we will discuss the implications of the ensemble of the results. These JFCs were all observed in R-band, and were all observed at relatively large heliocentric distances (usually >4 AU from the Sun) where the comets appeared inactive, thus minimizing coma contamination. We acknowledge the support of NASA grant NNX09AB44G, of NSF grant AST-0808004, and of the Astrophysical Research Consortium/Apache Point Observatory for this work. References: [1] Y. R. Fernandez et al., 2013, Icarus 226, 1138. [2] M. S. Kelley et al., 2013, Icarus 225, 475.

  14. Surface Albedo Variations Across Opportunity's Traverse in Meridiani Planum

    NASA Astrophysics Data System (ADS)

    Studer-Ellis, G. L.; Rice, M. S.; Johnson, J. R.; Bell, J. F., III

    2015-12-01

    Surface albedo measurements from the Mars Exploration Rover (MER) Opportunity mission can be used to help understand surface-atmosphere interactions at Meridiani Planum. Opportunity has acquired 117 albedo panoramas with the Pancam instrument as of sol 3870, across the first 40 km of its traverse. To date, only the first 32 panoramas have been reported upon in previous studies [1]. Here we present an analysis of the full set of PDS-released albedo observations from Opportunity and correlate our measurements with terrain type and known atmospheric events. To acquire a 360-degree albedo observation, Pancam's L1 ("clear") filter is used to take 27 broad-spectrum images, which are stitched into a mosaic. Pancam images are calibrated to reflectance factor (R*), which is taken as an approximation of the Lambertian albedo. Areas of interest are selected and average albedo calculations are applied to all of the selections. Results include the average albedo of each scene, as well as equal-area corrections where applicable, in addition to measurements of specific classes of surface features (e.g., outcrops, dusty terrain, and rover tracks). Average scene albedo measurements range from 0.11 ± 0.04 to 0.30 ± 0.04, with the highest value observed on sol 1290 (immediately after the planet-encircling dust storm of 2007). We compare these results to distance traveled, surface morphologies, local wind driven events, and dust opacity measurements. Future work will focus on correlating Pancam albedo values with orbital data from cameras such as HiRISE, CTX, MOC, THEMIS-VIS, and MARCI, and completion of the same analysis for the full Pancam albedo dataset from Spirit. References: [1] Bell, J. F., III, M. S. Rice, J. R. Johnson, and T. M. Hare (2008), Surface albedo observations at Gusev Crater and Meridiani Planum, Mars, J. Geophys. Res., 113, E06S18, doi:10.1029/2007JE002976.

  15. From Regional Cloud-Albedo to a Global Albedo Footprint - Studying Aerosol Effects on the Radiation Budget Using the Relation Between Albedo and Cloud Fraction

    NASA Astrophysics Data System (ADS)

    Bender, F.; Engström, A.; Karlsson, J.; Wood, R.; Charlson, R. J.

    2015-12-01

    Earth's albedo is the primary determinant of the amount of energy absorbed by the Earth-atmosphere system. The main factor controlling albedo is the amount of clouds present, but aerosols can affect and alter both clear-sky and cloudy-sky reflectance. How albedo depends on cloud fraction and how albedo varies at a given cloud fraction and a given cloud water content, reveals information about these aerosol effects on the radiation budget. Hence, the relation between total albedo and cloud fraction can be used for illustration and quantification of aerosol effects, and as a diagnostic tool, to test model performance. Here, we show examples of the utilisation of this relation focusing on satellite observations from CERES and MODIS on Aqua, as well as from Calipso and CloudSat, and performing comparisons with climate models on the way: In low-cloud regions in the subtropics, we find that climate models well represent a near-constant regional cloud albedo, and this representation has improved from CMIP3 to CMIP5. CMIP5 models indicate more reflective clouds in present-day climate than pre-industrial, as a result of increased aerosol burdens. On monthly mean time scale, models are found to over-estimate the regional cloud-brightening due to aerosols. On the global scale we find an increasing cloud albedo with increasing cloud fraction - a relation that is very well defined in observations, and less so in CMIP5 models. Cloud brightening from pre-industrial to present day is also seen on global scale. Further, controlling for both cloud fraction and cloud water content we can trace small variations in albedo, or perturbations of solar reflectivity, that create a near-global coherent geographical pattern that is consistent with aerosol impacts on climate, with albedo enhancement in regions dominant of known aerosol sources and suppression of albedo in regions associated with high rates of aerosol removal (deduced using CloudSat precipitation estimates). This mapping can be

  16. Classical Rotational Inertia of Solid {sup 4}He

    SciTech Connect

    Dash, J.G.; Wettlaufer, J.S.

    2005-06-17

    The observation of reduced rotational inertia in a cell containing solid {sup 4}He has been interpreted as evidence for superfluidity of the solid. We propose an alternative explanation: slippage of the solid, due to grain boundary premelting between the solid and dense adsorbed layers at the container wall. We calculate the range of film thickness, and determine the viscosity that will account for the missing rotational inertia. Grain boundary premelting also explains inertial anomalies in an earlier study of solid helium in porous glass and indicates that the liquid is partially superfluid.

  17. Effect of inertia on model flocks in a turbulent environment

    NASA Astrophysics Data System (ADS)

    Choudhary, Ashok; Venkataraman, Divya; Sankar Ray, Samriddhi

    2015-10-01

    We study flocking of self-propelled, interacting microorganisms with finite sizes and mass immersed in a turbulent flow. In the presence of the competing interactions of self-propulsion and the carrier turbulent flow, as is typical in nature, we show that including the effect of inertia is essential for the stability of flocks. We examine the problem from the point of view of global as well as local order and the statistics of the velocity of the microorganisms as a function of the inertia, the interaction radius, the level of self-propulsion as well as noise.

  18. An efficient method for computation of the manipulator inertia matrix

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Bejczy, Antal K.

    1989-01-01

    An efficient method of computation of the manipulator inertia matrix is presented. Using spatial notations, the method leads to the definition of the composite rigid-body spatial inertia, which is a spatial representation of the notion of augmented body. The previously proposed methods, the physical interpretations leading to their derivation, and their redundancies are analyzed. The proposed method achieves a greater efficiency by eliminating the redundancy in the intrinsic equations as well as by a better choice of coordinate frame for their projection. In this case, removing the redundancy leads to greater efficiency of the computation in both serial and parallel senses.

  19. Centrifugal inertia effects in two-phase face seal films

    NASA Technical Reports Server (NTRS)

    Basu, P.; Hughes, W. F.; Beeler, R. M.

    1987-01-01

    A simplified, semianalytical model has been developed to analyze the effect of centrifugal inertia in two-phase face seals. The model is based on the assumption of isothermal flow through the seal, but at an elevated temperature, and takes into account heat transfer and boiling. Using this model, seal performance curves are obtained with water as the working fluid. It is shown that the centrifugal inertia of the fluid reduces the load-carrying capacity dramatically at high speeds and that operational instability exists under certain conditions. While an all-liquid seal may be starved at speeds higher than a 'critical' value, leakage always occurs under boiling conditions.

  20. Analytical expression for the inverted inertia matrix of serial robots

    SciTech Connect

    Saha, S.K.

    1999-01-01

    This paper presents the analytical derivation of the inertia matrix and its inverse for an open-loop, serial-chain robot. The derivation allows one to write a recursive forward-dynamics algorithm for simulation purposes whose computational complexity is of order n, i.e., {Omicron}(n) -- n being the degrees of freedom of the robot under study. The proposed methodology is based on the Gaussian elimination of the inertia matrix, in contrast to, say, Kalman filtering, which is proposed elsewhere. The derivation is illustrated with a three-degrees-of-freedom planar robot.

  1. Otoancorin Knockout Mice Reveal Inertia is the Force for Hearing

    NASA Astrophysics Data System (ADS)

    Weddell, Thomas; Legan, P. Kevin; Lukashkina, Victoria A.; Goodyear, Richard J.; Welstead, Lindsy; Petit, Chistine; Russell, Ian J.; Lukashkin, Andrei N.; Richardson, Guy P.

    2011-11-01

    We demonstrate that in Otoa-/- mice, in which the inner-ear-specific protein otoancorin is absent, excitation of the outer hair cells and cochlear amplification is normal. This finding is remarkable because the tectorial membrane (TM), although remaining functionally attached to the outer hair cell bundles, is completely detached from the spiral limbus. Therefore, as in ancestral vertebrate auditory organs, where inertia provides the excitatory force to the hair cells, it is the inertia of the TM that must be important for exciting the outer hair cells, setting the sensitivity of their transducer conductance, and determining the precise timing of cochlear amplification.

  2. Thermal properties of Rhea's poles: Evidence for a meter-deep unconsolidated subsurface layer

    NASA Astrophysics Data System (ADS)

    Howett, C. J. A.; Spencer, J. R.; Hurford, T.; Verbiscer, A.; Segura, M.

    2016-07-01

    Cassini's Composite Infrared Spectrometer (CIRS) observed both of Rhea's polar regions during a close (2000 km) flyby on 9th March 2013 during orbit 183. Rhea's southern pole was again observed during a more distant (51,000 km) flyby on 10th February 2015 during orbit 212. The results show Rhea's southern winter pole is one of the coldest places directly observed in our Solar System: surface temperatures of 25.4 ± 7.4 K and 24.7 ± 6.8 K are inferred from orbit 183 and 212 data, respectively. The surface temperature of the northern summer pole inferred from orbit 183 data is warmer: 66.6 ± 0.6 K. Assuming the surface thermophysical properties of the two polar regions are comparable then these temperatures can be considered a summer and winter seasonal temperature constraint for the polar region. Orbit 183 will provide solar longitude (LS) coverage at 133° and 313° for the summer and winter poles respectively, while orbit 212 provides an additional winter temperature constraint at LS 337°. Seasonal models with bolometric albedo values between 0.70 and 0.74 and thermal inertia values between 1 and 46 J m-2 K-1 s-1/2 (otherwise known as MKS units) can provide adequate fits to these temperature constraints (assuming the winter temperature is an upper limit). Both these albedo and thermal inertia values agree within the uncertainties with those previously observed on both Rhea's leading and trailing hemispheres. Investigating the seasonal temperature change of Rhea's surface is particularly important, as the seasonal wave is sensitive to deeper surface temperatures (∼tens of centimeters to meter depths) than the more commonly reported diurnal wave (typically less than a centimeter), the exact depth difference dependent upon the assumed surface properties. For example, if a surface porosity of 0.5 and thermal inertia of 25 MKS is assumed then the depth of the seasonal thermal wave is 76 cm, which is much deeper than the ∼0.5 cm probed by diurnal studies of Rhea

  3. The albedo, effective temperature, and energy balance of Neptune, as determined from Voyager data

    NASA Technical Reports Server (NTRS)

    Pearl, J. C.; Conrath, B. J.

    1991-01-01

    Data from the Voyager infrared spectrometer and radiometer (IRIS) investigation are used in determining the albedo, effective temperature, and energy balance of Neptune. From broadband radiometric observations made at phase angles of 14 deg and 134 deg, together with measurements at intermediate phase angles from the literature, an orbital mean value of 0.290 +/-0.067 is obtained for the bolometric Bond albedo. This yields an equilibrium temperature Teq = 46.6 +/-1.1 K. From thermal spectra obtained over latitudes from pole to pole an effective temperature Teff = 59.3 +/-0.8 K is derived. This represents a substantial improvement over previously determined values. The energy balance of Neptune is therefore E = 2.61 +/-0.28, which is in agreement with previous results. The reduced uncertainty in this value is due to the improved determination of the effective temperature.

  4. A microphysically-based approach to modeling emissivity and albedo of the martian seasonal caps

    USGS Publications Warehouse

    Eluszkiewicz, J.; Moncet, J.-L.; Titus, T.N.; Hansen, G.B.

    2005-01-01

    A new model of albedo and emissivity of the martian seasonal caps represented as porous CO2 slabs containing spherical voids and dust particles is described. In the model, a radiative transfer model is coupled with a microphysical model in order to link changes in albedo and emissivity to changes in porosity caused by ice metamorphism. The coupled model is capable of reproducing temporal changes in the spectra of the caps taken by the Thermal Emission Spectrometer onboard the Mars Global Surveyor and it can be used as the forward model in the retrievals of the caps' physical properties (porosity, dust abundance, void and dust grain size) from the spectra. Preliminary results from such inversion studies are presented. ?? 2004 Elsevier Inc. All rights reserved.

  5. Survey of TES high albedo events in Mars' northern polar craters

    USGS Publications Warehouse

    Armstrong, J.C.; Nielson, S.K.; Titus, T.N.

    2007-01-01

    Following the work exploring Korolev Crater (Armstrong et al., 2005) for evidence of crater interior ice deposits, we have conducted a survey of Thermal Emission Spectroscopy (TES) temperature and albedo measurements for Mars' northern polar craters larger than 10 km. Specifically, we identify a class of craters that exhibits brightening in their interiors during a solar longitude, Ls, of 60 to 120 degrees, roughly depending on latitude. These craters vary in size, latitude, and morphology, but appear to have a specific regional association on the surface that correlates with the distribution of subsurface hydrogen (interpreted as water ice) previously observed on Mars. We suggest that these craters, like Korolev, exhibit seasonal high albedo frost events that indicate subsurface water ice within the craters. A detailed study of these craters may provide insight in the geographical distribution of the ice and context for future polar missions. Copyright 2007 by the American Geophysical Union.

  6. The albedo of snow for partially cloudy skies

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Chang, A. T. C.

    1980-01-01

    The input parameters of the model are atmospheric precipitable water, ozone content, turbidity, cloud optical thickness, size and shape of ice crystal of snow and surface pressure. The model outputs spectral and integrated solar flux snow reflectance as a function of solar elevation and fractional cloudcover. The model is illustrated using representative parameters for the Antarctic coastal regions. The albedo for a clear sky depends inversely on the solar elevation. At high elevation the albedo depends primarily upon the grain size; at low elevation this dependence is on grain size and shape. The gradient of the albedo-elevation curve increases as the grains get larger and faceted. The albedo for a dense overcast is a few percent higher than the clear sky albedo at high elevations. A simple relation between the grain size and the overcast albedo is obtained. For a set of grain size and shape, the albedo matrices (the albedo as a function of solar elevation and fractional cloudcover) are tabulated.

  7. Shallow Lunar Hydrogen and Forward-Scattered Albedo Protons

    NASA Astrophysics Data System (ADS)

    Wilson, J. K.; Schwadron, N.; Jordan, A. P.; Spence, H. E.; Looper, M. D.; Townsend, L. W.

    2015-11-01

    The CRaTER instrument sees a ~40% higher flux of lunar albedo protons (>65 MeV) at grazing angles compared to the nadir direction. A shallow layer (<10 cm) of hydrated lunar regolith may enhance the yield of forward-scattered albedo protons.

  8. Effect of shaddock albedo addition on the properties of frankfurters.

    PubMed

    Shan, Bing; Li, Xingmin; Pan, Teng; Zheng, Limin; Zhang, Hao; Guo, Huiyuan; Jiang, Lu; Zhen, Shaobo; Ren, Fazheng

    2015-07-01

    To explore the potential as a natural auxiliary emulsifier, shaddock albedo was added into frankfurters at six different levels: 0.0, 2.5, 5.0, 7.5, 10 and 12.5 %. The emulsion capacity (EC) of meat batters and cooking properties of frankfurters were evaluated. EC of meat batters was improved with the addition of shaddock albedo and the maximum value was reached at the 5 % albedo concentration. The addition of shaddock albedo resulted in lower cooking losses of frankfurters, with the lowest value obtained at the 7.5 % level. The presence of shaddock albedo decreased the total expressible fluid (TEF) and the proportion of fat in total expressible fluid (PF) which indicated the emulsion stability of frankfurters and the lowest values both occurred at the concentration of 7.5 %. Shaddock albedo inclusion increased the lightness and yellowness of frankfurters and decreased redness. Texture profile analysis showed increased hardness and decreased chewiness of frankfurters with the addition of shaddock albedo. Consequently, shaddock albedo could be a potential source of auxiliary emulsifier filler for emulsion-type meat products. PMID:26139927

  9. Anthropogenic desertification by high-albedo pollution Observations and modeling

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Rosenberg, N. W.; Rosenberg, E.

    1974-01-01

    ERTS-1 MSS albedo data of Western Negev, Sinai and the Gaza strip are presented. A sharp contrast in albedo exists across the Negev-Sinai and Negev-Gaza strip borders. Anthropogenic desertification has occurred on the Arab side due to overgrazing and Bedouin agriculture, whereas natural vegetation grows much more abundantly on the Israeli side.

  10. Greenland surface albedo changes 1981-2012 from satellite observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant melt over Greenland has been observed during the last several decades associated with extreme warming events over the northern Atlantic Ocean. An analysis of surface albedo change over Greenland is presented, using a 32-year consistent satellite albedo product from the Global Land Surfac...

  11. Asymmetry in the Diurnal Variation of Surface Albedo

    NASA Technical Reports Server (NTRS)

    Mayor, S.; Smith, W. L., Jr.; Nguyen, L.; Alberta, T. A.; Minnis, P.; Whitlock, C. H.; Schuster, G. L.

    1996-01-01

    Remote sensing of surface properties and estimation of clear-sky and surface albedo generally assumes that the albedo depends only on the solar zenith angle. The effects of dew, frost, and precipitation as well as evaporation and wind can lead to some systematic diurnal variability resulting in an asymmetric diurnal cycle of albedo. This paper examines the symmetry of both surface-observed albedos and top-of-the-atmosphere (TOA) albedos derived from satellite data. Broadband and visible surface albedos were measured at the Department of Energy Atmospheric Radiation Measurement (ARM) Program Southern Great Plains Central Facility, at some fields near the ARM site, and over a coniferous forest in eastern Virginia. Surface and wind conditions are available for most cases. GOES-8 satellite radiance data are converted to broadband albedo using bidirectional reflectance functions and an empirical narrowband-to-broadband relationship. The initial results indicate that surface moisture has a significant effect and can change the albedo in the afternoon by 20% relative to its morning counterpart. Such effects may need to be incorporated in mesoscale and even large-scale models of atmospheric processes.

  12. Thermal imaging for input to terrestrial and planetary thermal models (Invited)

    NASA Astrophysics Data System (ADS)

    Gillespie, A. R.

    2013-12-01

    therefore lower SNR than warmer targets. This especially is true at night, for example on Mars. Thermal inertia, a measure of the resistance of a surface to changing its T as energy is added or subtracted to it, can be estimated from day-night temperature differences. It can in principle be used to learn something about the porosity, rock/soil ratios, the presence of thin veneers of sand, or other non-compositional characteristics of a surface. Quantitative measures of T, ɛ and thermal inertia are needed for thermal modeling. However, calculating thermal inertia requires accounting for topography and albedo and is more challenging than just estimating T, and therefore on both Earth and Mars approximations to it are commonly used photointerpretively, just as images of T images and even derived ɛ are sometimes used photointerpretively also.

  13. NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

    NASA Astrophysics Data System (ADS)

    Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; Masiero, J.; Sonnett, S.; Wright, E. L.

    2016-09-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids (NEAs) and 8885 other asteroids. Of the NEAs, 84% NEAs did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within ±∼20% and ±∼40%, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large (>100 m), and have low albedos.

  14. NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

    NASA Astrophysics Data System (ADS)

    Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; Masiero, J.; Sonnett, S.; Wright, E. L.

    2016-09-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids (NEAs) and 8885 other asteroids. Of the NEAs, 84% NEAs did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within ±˜20% and ±˜40%, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large (>100 m), and have low albedos.

  15. Hydrodynamic interactions of two nearly touching Brownian spheres in a stiff potential: Effect of fluid inertia

    NASA Astrophysics Data System (ADS)

    Radiom, Milad; Robbins, Brian; Paul, Mark; Ducker, William

    2015-02-01

    The hydrodynamic interaction of two closely spaced micron-scale spheres undergoing Brownian motion was measured as a function of their separation. Each sphere was attached to the distal end of a different atomic force microscopy cantilever, placing each sphere in a stiff one-dimensional potential (0.08 Nm-1) with a high frequency of thermal oscillations (resonance at 4 kHz). As a result, the sphere's inertial and restoring forces were significant when compared to the force due to viscous drag. We explored interparticle gap regions where there was overlap between the two Stokes layers surrounding each sphere. Our experimental measurements are the first of their kind in this parameter regime. The high frequency of oscillation of the spheres means that an analysis of the fluid dynamics would include the effects of fluid inertia, as described by the unsteady Stokes equation. However, we find that, for interparticle separations less than twice the thickness of the wake of the unsteady viscous boundary layer (the Stokes layer), the hydrodynamic interaction between the Brownian particles is well-approximated by analytical expressions that neglect the inertia of the fluid. This is because elevated frictional forces at narrow gaps dominate fluid inertial effects. The significance is that interparticle collisions and concentrated suspensions at this condition can be modeled without the need to incorporate fluid inertia. We suggest a way to predict when fluid inertial effects can be ignored by including the gap-width dependence into the frequency number. We also show that low frequency number analysis can be used to determine the microrheology of mixtures at interfaces.

  16. Hydrodynamic interactions of two nearly touching Brownian spheres in a stiff potential: Effect of fluid inertia

    SciTech Connect

    Radiom, Milad Ducker, William; Robbins, Brian; Paul, Mark

    2015-02-15

    The hydrodynamic interaction of two closely spaced micron-scale spheres undergoing Brownian motion was measured as a function of their separation. Each sphere was attached to the distal end of a different atomic force microscopy cantilever, placing each sphere in a stiff one-dimensional potential (0.08 Nm{sup −1}) with a high frequency of thermal oscillations (resonance at 4 kHz). As a result, the sphere’s inertial and restoring forces were significant when compared to the force due to viscous drag. We explored interparticle gap regions where there was overlap between the two Stokes layers surrounding each sphere. Our experimental measurements are the first of their kind in this parameter regime. The high frequency of oscillation of the spheres means that an analysis of the fluid dynamics would include the effects of fluid inertia, as described by the unsteady Stokes equation. However, we find that, for interparticle separations less than twice the thickness of the wake of the unsteady viscous boundary layer (the Stokes layer), the hydrodynamic interaction between the Brownian particles is well-approximated by analytical expressions that neglect the inertia of the fluid. This is because elevated frictional forces at narrow gaps dominate fluid inertial effects. The significance is that interparticle collisions and concentrated suspensions at this condition can be modeled without the need to incorporate fluid inertia. We suggest a way to predict when fluid inertial effects can be ignored by including the gap-width dependence into the frequency number. We also show that low frequency number analysis can be used to determine the microrheology of mixtures at interfaces.

  17. The albedo effect on neutron transmission probability.

    PubMed

    Khanouchi, A; Sabir, A; Boulkheir, M; Ichaoui, R; Ghassoun, J; Jehouani, A

    1997-01-01

    The aim of this study is to evaluate the albedo effect on the neutron transmission probability through slab shields. For this reason we have considered an infinite homogeneous slab having a fixed thickness equal to 20 lambda (lambda is the mean free path of the neutron in the slab). This slab is characterized by the factor Ps (scattering probability) and contains a vacuum channel which is formed by two horizontal parts and an inclined one (David, M. C. (1962) Duc and Voids in shields. In Reactor Handbook, Vol. III, Part B, p. 166). The thickness of the vacuum channel is taken equal to 2 lambda. An infinite plane source of neutrons is placed on the first of the slab (left face) and detectors, having windows equal to 2 lambda, are placed on the second face of the slab (right face). Neutron histories are sampled by the Monte Carlo method (Booth, T. E. and Hendricks, J. S. (1994) Nuclear Technology 5) using exponential biasing in order to increase the Monte Carlo calculation efficiency (Levitt, L. B. (1968) Nuclear Science and Engineering 31, 500-504; Jehouani, A., Ghassoun, J. and Abouker, A. (1994) In Proceedings of the 6th International Symposium on Radiation Physics, Rabat, Morocco) and we have applied the statistical weight method which supposes that the neutron is born at the source with a unit statistical weight and after each collision this weight is corrected. For different values of the scattering probability and for different slopes of the inclined part of the channel we have calculated the neutron transmission probability for different positions of the detectors versus the albedo at the vacuum channel-medium interface. Some analytical representations are also presented for these transmission probabilities. PMID:9463883

  18. Global color and albedo variations on Io

    USGS Publications Warehouse

    McEwen, A.S.

    1988-01-01

    Three multispectral mosaics of Io have been produced from Voyager imaging data: a global mosaic from each of the Voyager 1 and Voyager 2 data sets and a high-resolution mosaic of the region surrounding the volcano Ra Patera. The mosaics are maps of normal albedo and color in accurate geometric map formats. Io's photometric behavior, mapped with a two-image technique, is spatially variable, especially in the bright white areas. The disk-integrated color and albedo of the satellite have been remarkably constant over recent decades, despite the volcanic activity and the many differences between Voyager 1 and 2 images (acquired just 4 months apart). This constancy is most likely due to the consistent occurrence of large Pele-type plumes with relatively dark, red deposits in the region from long 240 to 360??. A transient brightening southeast of Pele during the Voyager 1 encounter was probably due to real changes in surface and/or atmospheric materials, rather than to photometric behavior. The intrinsic spectral variability of Io, as seen in a series of two-dimensional histograms of the multispectral mosaics, consists of continuous variation among three major spectral end members. The data were mapped into five spectral units to compare them with laboratory measurements of candidate surface materials and to show the planimetric distributions. Unit 1 is best fit by the spectral reflectance of ordinary elemental sulfur, and it is closely associated with the Peletype plume deposits. Unit 2 is strongly confined to the polar caps above about latitude ??50??, but its composition is unknown. Unit 5 is probably SO2 with relatively minor contamination; it is concentrated in the equatorial region and near the long-lived Prometheus-type plumes. Units 3 and 4 are gradational between units 1 and 5. In addition to SO2 and elemental sulfur, other plausible components of the surface are polysulfur oxides, FeCl2, Na2S, and NaHS. ?? 1988.

  19. Fire disturbance effects on land surface albedo in Alaskan tundra

    NASA Astrophysics Data System (ADS)

    French, Nancy H. F.; Whitley, Matthew A.; Jenkins, Liza K.

    2016-03-01

    The study uses satellite Moderate Resolution Imaging Spectroradiometer albedo products (MCD43A3) to assess changes in albedo at two sites in the treeless tundra region of Alaska, both within the foothills region of the Brooks Range, the 2007 Anaktuvuk River Fire (ARF) and 2012 Kucher Creek Fire (KCF). Results are compared to each other and other studies to assess the magnitude of albedo change and the longevity of impact of fire on land surface albedo. In both sites there was a marked decrease of albedo in the year following the fire. In the ARF, albedo slowly increased until 4 years after the fire, when it returned to albedo values prior to the fire. For the year immediately after the fire, a threefold difference in the shortwave albedo decrease was found between the two sites. ARF showed a 45.3% decrease, while the KCF showed a 14.1% decrease in shortwave albedo, and albedo is more variable in the KCF site than ARF site 1 year after the fire. These differences are possibly the result of differences in burn severity of the two fires, wherein the ARF burned more completely with more contiguous patches of complete burn than KCF. The impact of fire on average growing season (April-September) surface shortwave forcing in the year following fire is estimated to be 13.24 ± 6.52 W m-2 at the ARF site, a forcing comparable to studies in other treeless ecosystems. Comparison to boreal studies and the implications to energy flux are discussed in the context of future increases in fire occurrence and severity in a warming climate.

  20. Further Evidence for Cognitive Inertia of Persons with Mental Retardation.

    ERIC Educational Resources Information Center

    Ellis, Norman R.; Dulaney, Cynthia L.

    1991-01-01

    Forty young adults with mental retardation (MR) were compared to 40 young adults without mental retardation in tests examining postpractice interference effects in naming colors of Stroop words. The study concluded that practice developed automatized reading suppression responses which held greater cognitive inertia for longer periods among MR…

  1. Chimera states in coupled Kuramoto oscillators with inertia.

    PubMed

    Olmi, Simona

    2015-12-01

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry. PMID:26723164

  2. 40 CFR 1066.250 - Base inertia verification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... mean values as described in 40 CFR 1065.602(b). (7) Calculate the base inertia error, I berror, for... nominal acceleration rate and the nominal deceleration rate. (4) Use good engineering judgment to select two additional acceleration and deceleration rates that cover the middle and upper rates...

  3. Chimera states in coupled Kuramoto oscillators with inertia

    NASA Astrophysics Data System (ADS)

    Olmi, Simona

    2015-12-01

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.

  4. Inertia Parameter Identification from Base Excitation Test Dat

    NASA Astrophysics Data System (ADS)

    Fuellekrug, U.; Schedlinski, C.

    2004-08-01

    With the purpose to further investigate and improve a method for the identification of inertia parameters, tests with flexible test structures have been carried out. Reference data for the inertia parameters were obtained from a Finite Element model and from conventional weighing and pendulum measurements. For the realization of the base excitation a six-axis vibration simulator was utilized. The base forces were recorded with a special Force Measurement Device (FMD), and the base accelerations of the test structures were measured by accelerometers. Each of the 3 translational and 3 rotational axes of the multi-axial test facility was driven by a sine sweep signal with an appropriate base acceleration input. The application of the identification algorithm to the measured data showed that an acceptable identification of mass and mass moments of inertia is possible. However, a highly accurate identification of the center of gravity location could not be achieved. The results of the analyses are discussed and the advantages and limits of the present method are pointed out. Recommendations for the practical application and improved center of gravity identification are given. Keywords: Inertia parameters, base excitation, multi- axial test facilities, vibration testing.

  5. Chimera states in coupled Kuramoto oscillators with inertia

    SciTech Connect

    Olmi, Simona

    2015-12-15

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.

  6. Overview of Theories and Experiments on Electromagnetic Inertia Manipulation Propulsion

    NASA Astrophysics Data System (ADS)

    Brito, Hector H.; Elaskar, Sergio A.

    2005-02-01

    Experiments performed by independent research teams, suggesting that "propellantless" propulsion without external assistance is being achieved by means of electromagnetic inertia manipulation, are discussed here and compared within the framework of competing theoretical formulations. The authors' theory relies upon the fact that the electromagnetic (EM) field can exhibit a whole non-vanishing momentum in the "matter" frame, even for stationary regimes, provided Minkowski's energy-momentum tensor holds for EM fields in matter. In a closed system this EM momentum can be converted into mechanical momentum, so that electromagnetic inertia intervenes to modify the inertial properties of the generating device. Another theory, set forth by Corum and based on Slepian's works, states that the inertia manipulation effect stems from the Heaviside force density in vacuum, which is shown to lead to a zero instantaneous volume integrated force on a closed system. Although the system momentum is not conserved in the reported experiments, the propulsion effect is shown to be consistent with an alternative formulation of Minkowski's EM force density that correctly predicts former peer-reviewed experimental results. A fourth theory by J. Woodward, based on "Machian" mass/inertia fluctuations due to transient mass modifications, purportedly predicts the observed results but flaws are found in the predictions which, when corrected, considerably disagree with the experimental data. Finally, recent developments in vacuum physics allows building a conceptual framework with the potential of resolving the apparent violation of momentum conservation, closely connected to Minkowski's energy momentum tensor and its lack of symmetry.

  7. Effect of fluid inertia on probe-tack adhesion

    NASA Astrophysics Data System (ADS)

    Dias, Eduardo O.; Miranda, José A.

    2012-01-01

    One way of determining the adhesive strength of liquids is provided by a probe-tack test, which involves measuring the force required to pull apart two parallel flat plates separated by a thin fluid film. The large majority of existing theoretical and experimental work on probe-tack adhesion use very viscous fluids and considers relatively low lifting plate velocities, so that effects due to fluid inertia can be neglected. However, the employment of low-viscosity fluids and the increase in operating speeds of modern lifting apparatus can modify this scenario. By dealing with a proper gap averaging of the Navier-Stokes equation, we obtain a modified Darcy-law-like description of the problem and derive an adhesion force which incorporates the effects of fluid inertia, fluid viscosity (for Newtonian and power law fluids), and the contribution of the compliance and inertia of the probe-tack apparatus. Our results indicate that fluid inertia may have a significant influence on the adhesion force profiles, inducing a considerable increase in the force peaks and producing oscillations in the force-displacement curves as the plate-plate separation is increased. The combined role of inertial and non-Newtonian fluid behaviors on the adhesion force response is also investigated.

  8. The Zone of Inertia: Absorptive Capacity and Organizational Change

    ERIC Educational Resources Information Center

    Godkin, Lynn

    2010-01-01

    Purpose: The purpose of this paper is to describe how interruptions in organizational learning effect institutional absorptive capacity and contribute to organizational inertia. Design/methodology/approach: An exploratory model is presented as a heuristic to describe how interruptions in organizational learning affect absorptive capacity.…

  9. More about the moment of inertia of Mars

    NASA Technical Reports Server (NTRS)

    Kaula, William M.; Sleep, Norman H.; Phillips, Roger J.

    1989-01-01

    Differences between Mars and other terrestrial planets are discussed. Unlike other terrestrial planets, Mars has two nonhydrostatic components of moments of inertia that are nearly equal. The most probable value of I/MR-squared is slightly less than 0.3650.

  10. Obstacles to Reasoning about Inertia in Different Contexts

    ERIC Educational Resources Information Center

    Yerdelen-Damar, Sevda

    2015-01-01

    The present study investigated the underlying reasons for difficulties faced by students when they applied the concept of inertia across varying contexts. The participants of the study included five high school students. Data obtained from interviews were interpreted from the perspectives of the coordination class and epistemological framing…

  11. Moment of Inertia of a Ping-Pong Ball

    ERIC Educational Resources Information Center

    Cao, Xian-Sheng

    2012-01-01

    This note describes how to theoretically calculate and experimentally measure the moment of inertia of a Ping-Pong[R] ball. The theoretical calculation results are in good agreement with the experimental measurements that can be reproduced in an introductory physics laboratory.

  12. A method for measuring the inertia properties of rigid bodies

    NASA Astrophysics Data System (ADS)

    Gobbi, M.; Mastinu, G.; Previati, G.

    2011-01-01

    A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.

  13. Role of inertia in the fracture of rock

    SciTech Connect

    Passman, S.L.; Grady, D.E.; Rundle, J.B.

    1980-08-01

    A theory for the accumulation of damage in one dimension in fast deformation of a brittle material is developed. The theory is consistent with thermodynamics and takes crack inertia into account. The problem of damage accumulation due to a step pulse in strain is solved, and shows good agreement with experimental results.

  14. Generating multi-scale albedo look-up maps using MODIS BRDF/Albedo products and landsat imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface albedo determines radiative forcing and is a key parameter for driving Earth’s climate. Better characterization of surface albedo for individual land cover types can reduce the uncertainty in estimating changes to Earth’s radiation balance due to land cover change. This paper presents a mult...

  15. Relationship between cloud radiative forcing, cloud fraction and cloud albedo, and new surface-based approach for determining cloud albedo

    SciTech Connect

    Liu, Y.; Wu, W.; Jensen, M. P.; Toto, T.

    2011-07-21

    This paper focuses on three interconnected topics: (1) quantitative relationship between surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo; (2) surface-based approach for measuring cloud albedo; (3) multiscale (diurnal, annual and inter-annual) variations and covariations of surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo. An analytical expression is first derived to quantify the relationship between cloud radiative forcing, cloud fraction, and cloud albedo. The analytical expression is then used to deduce a new approach for inferring cloud albedo from concurrent surface-based measurements of downwelling surface shortwave radiation and cloud fraction. High-resolution decade-long data on cloud albedos are obtained by use of this surface-based approach over the US Department of Energy's Atmospheric Radiaton Measurement (ARM) Program at the Great Southern Plains (SGP) site. The surface-based cloud albedos are further compared against those derived from the coincident GOES satellite measurements. The three long-term (1997-2009) sets of hourly data on shortwave cloud radiative forcing, cloud fraction and cloud albedo collected over the SGP site are analyzed to explore the multiscale (diurnal, annual and inter-annual) variations and covariations. The analytical formulation is useful for diagnosing deficiencies of cloud-radiation parameterizations in climate models.

  16. Arid land monitoring using Landsat albedo difference images

    USGS Publications Warehouse

    Robinove, Charles J.; Chavez, Pat S., Jr.; Gehring, Dale G.; Holmgren, Ralph

    1981-01-01

    The Landsat albedo, or percentage of incoming radiation reflected from the ground in the wavelength range of 0.5 [mu]m to 1.1 [mu]m, is calculated from an equation using the Landsat digital brightness values and solar irradiance values, and correcting for atmospheric scattering, multispectral scanner calibration, and sun angle. The albedo calculated for each pixel is used to create an albedo image, whose grey scale is proportional to the albedo. Differencing sequential registered images and mapping selected values of the difference is used to create quantitative maps of increased or decreased albedo values of the terrain. All maps and other output products are in black and white rather than color, thus making the method quite economical. Decreases of albedo in arid regions may indicate improvement of land quality; increases may indicate degradation. Tests of the albedo difference mapping method in the Desert Experimental Range in southwestern Utah (a cold desert with little long-term terrain change) for a four-year period show that mapped changes can be correlated with erosion from flash floods, increased or decreased soil moisture, and increases or decreases in the density of desert vegetation, both perennial shrubs and annual plants. All terrain changes identified in this test were related to variations in precipitation. Although further tests of this method in hot deserts showing severe "desertification" are needed, the method is nevertheless recommended for experimental use in monitoring terrain change in other arid and semiarid regions of the world.

  17. The Temporal Evolution of the Albedo of Seasonal Sea Ice

    NASA Astrophysics Data System (ADS)

    Perovich, D. K.; Polashenski, C.; Eicken, H.; Grenfell, T. C.

    2009-12-01

    The ice-albedo feedback mechanism plays a key role in the heat budget of the Arctic sea ice cover and has climate implications. Seasonal ice is now the dominant Arctic ice type and has a significant impact on the large-scale albedo. The albedo of shorefast, seasonal ice was measured from April through late June for five field seasons. There was considerable interannual variability in the seasonal evolution of albedo, and consequently the solar heat input to the ice and upper ocean. In one year there was a monotonic decrease in areally averaged albedo after the onset of melt, while in others there were significant fluctuations of up to 0.4 over periods of only a few days. For all of the different evolutionary pathways there were two key drivers of albedo; the timing of the onset of melt and the areal coverage of melt ponds. Melt ponds on undeformed seasonal ice have been observed to reach coverages as large as 80% in only a few days. Just as rapidly coverages have been observed to drop to 7% as the ponds drained. The evolution of melt ponds is the key to understanding the evolution of seasonal ice albedo during the early stages of melt.

  18. Albedo reduction by dirty snow: measurements and implications

    NASA Astrophysics Data System (ADS)

    Zender, C. S.; Gallet, J.; Domine, F.; Picard, G.

    2008-12-01

    Industrial and biomass burning emissions of black carbon (BC) from low- and mid-latitudes dominate the radiative forcing by absorbing impurities trapped in snow and ice at mid- and high- northern latitudes. Correct model representation of albedo reduction by BC-contaminated snow is crucial because our GCM simulations show that dirty snow can explain about 30% of the observed 20th century Arctic warming. Until now, measurements of actual snow darkening by BC have been attempted only in the field, under non- reproducible conditions, and limited to the environmental BC concentration. We have conducted the first measurements of the direct effect of BC-contamination on snow albedo by in a controlled environment. We doped natural snow with a commercially available BC-analogue and measured the resulting albedo change at visible and near-infrared wavelengths. Snow albedo was measured in a (portable) integrating sphere system. Snow grain size is estimated from the near-infrared albedo. Snow density, temperature, and BC properties were known a priori. The albedo measurement reproducibility is about 1% for natural snow. Our measurements agree with model predictions that BC concentrations from 250 ppbm to 200 ppmm darken snow albedo by 1--70%. Our results lend confidence to the current model representations of surface darkening in the cryosphere. Applying these methods to impurity records in polar ice cores yields surface radiative forcing estimates that can be extrapolated to regional scales.

  19. The Gamma-ray Albedo of the Moon

    SciTech Connect

    Moskalenko, Igor V.; Porter, Troy A.; /UC, Santa Cruz

    2007-09-28

    We use the GEANT4 Monte Carlo framework to calculate the {gamma}-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of {gamma}-rays from the Moon is very steep with an effective cutoff around 3-4 GeV (600 MeV for the inner part of the Moon disk) and exhibits a narrow pion-decay line at 67.5 MeV, perhaps unique in astrophysics. Apart from other astrophysical sources, the albedo spectrum of the Moon is well understood, including its absolute normalization; this makes it a useful 'standard candle' for {gamma}-ray telescopes. The steep albedo spectrum also provides a unique opportunity for energy calibration of {gamma}-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). Since the albedo flux depends on the incident CR spectrum which changes over the solar cycle, it is possible to monitor the CR spectrum using the albedo {gamma}-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo {gamma}-rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the LAT to monitor the CR spectrum near the Earth beyond the lifetime of the PAMELA.

  20. The Gamma-Ray Albedo of the Moon

    SciTech Connect

    Moskalenko, I.V.; Porter, T.A.; /UC, Santa Cruz

    2008-03-25

    We use the GEANT4 Monte Carlo framework to calculate the {gamma}-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of {gamma}-rays from the Moon is very steep with an effective cutoff around 3-4 GeV (600 MeV for the inner part of the Moon disk) and exhibits a narrow pion-decay line at 67.5 MeV, perhaps unique in astrophysics. Apart from other astrophysical sources, the albedo spectrum of the Moon is well understood, including its absolute normalization; this makes it a useful 'standard candle' for {gamma}-ray telescopes. The steep albedo spectrum also provides a unique opportunity for energy calibration of {gamma}-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). Since the albedo flux depends on the incident CR spectrum which changes over the solar cycle, it is possible to monitor the CR spectrum using the albedo {gamma}-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo {gamma}-rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the LAT to monitor the CR spectrum near the Earth beyond the lifetime of the PAMELA.

  1. Earth albedo neutrons from 10 to 100 MeV.

    NASA Technical Reports Server (NTRS)

    Preszler, A. M.; Simnett, G. M.; White, R. S.

    1972-01-01

    We report the measurement of the energy and angular distributions of earth albedo neutrons from 10 to 100 MeV at 40 deg N geomagnetic latitude from a balloon at 120,000 ft, below 4.65 g/sq cm. The albedo-neutron omnidirectional energy distribution is flat to 50 MeV, then decreases with energy. The absolute neutron energy distribution is of the correct strength and shape for the albedo neutrons to be the source of the protons trapped in earth's inner radiation belt.

  2. Variable control of neutron albedo in toroidal fusion devices

    DOEpatents

    Jassby, Daniel L.; Micklich, Bradley J.

    1986-01-01

    An arrangement is provided for controlling neutron albedo in toroidal fusion devices having inboard and outboard vacuum vessel walls for containment of the neutrons of a fusion plasma. Neutron albedo material is disposed immediately adjacent the inboard wall, and is movable, preferably in vertical directions, so as to be brought into and out of neutron modifying communication with the fusion neutrons. Neutron albedo material preferably comprises a liquid form, but may also take pebble, stringer and curtain-like forms. A neutron flux valve, rotatable about a vertical axis is also disclosed.

  3. Lunar Terrain and Albedo Reconstruction from Apollo Imagery

    NASA Technical Reports Server (NTRS)

    Nefian, Ara V.; Kim, Taemin; Broxton, Michael; Moratto, Zach

    2010-01-01

    Generating accurate three dimensional planetary models and albedo maps is becoming increasingly more important as NASA plans more robotics missions to the Moon in the coming years. This paper describes a novel approach for separation of topography and albedo maps from orbital Lunar images. Our method uses an optimal Bayesian correlator to refine the stereo disparity map and generate a set of accurate digital elevation models (DEM). The albedo maps are obtained using a multi-image formation model that relies on the derived DEMs and the Lunar- Lambert reflectance model. The method is demonstrated on a set of high resolution scanned images from the Apollo era missions.

  4. Global color and albedo variations on Triton

    NASA Technical Reports Server (NTRS)

    Mcewen, Alfred S.

    1990-01-01

    Global multispectral mosaics of Triton have been produced from Voyager approach images; six spectral units are defined and mapped. The margin of the south polar cap (SPC) is scalloped and ranges in latitude from + 10 deg to -30 deg. A bright fringe is closely associated with the cap's margin; form it, diffuse bright rays extend north-northeast for hundreds of kilometers. Thus, the rays may consist of fringe materials that were redistributed by northward-going Coriolis-deflected winds. From 1977 to 1989, Triton's full-disk spectrum changed from markedly red and UV-dark to nearly neutral white and UV-bright. This spectral change can be explained by new deposition of nitrogen frost over both the northern hemisphere and parts of a formerly redder SPC. Frost deposition in the southern hemisphere during southern summer is possible over relatively high albedo areas of the cap (Stansberry et al., 1990), which helps to explain the apparent stability of the unexpectedly large SPC and the presence of the bright fringe.

  5. SCAP. Point Kernel Single or Albedo Scatter

    SciTech Connect

    Disney, R.K.; Bevan, S.E.

    1982-08-05

    SCAP solves for radiation transport in complex geometries using the single or albedo-scatter point kernel method. The program is designed to calculate the neutron or gamma-ray radiation level at detector points located within or outside a complex radiation scatter source geometry or a user-specified discrete scattering volume. The geometry is described by zones bounded by intersecting quadratic surfaces with an arbitrary maximum number of boundary surfaces per zone. The anisotropic point sources are described as point-wise energy dependent distributions of polar angles on a meridian; isotropic point sources may be specified also. The attenuation function for gamma rays is an exponential function on the primary source leg and the scatter leg with a buildup factor approximation to account for multiple scatter on the scatter leg. The neutron attenuation function is an exponential function using neutron removal cross sections on the primary source leg and scatter leg. Line or volumetric sources can be represented as distributions of isotropic point sources, with uncollided line-of-sight attenuation and buildup calculated between each source point and the detector point.

  6. Effects of electron inertia in collisionless magnetic reconnection

    SciTech Connect

    Andrés, Nahuel Gómez, Daniel; Martin, Luis; Dmitruk, Pablo

    2014-07-15

    We present a study of collisionless magnetic reconnection within the framework of full two-fluid MHD for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure and electron inertia. We performed 2.5D simulations using a pseudo-spectral code with no dissipative effects. We check that the ideal invariants of the problem are conserved down to round-off errors. Our numerical results confirm that the change in the topology of the magnetic field lines is exclusively due to the presence of electron inertia. The computed reconnection rates remain a fair fraction of the Alfvén velocity, which therefore qualifies as fast reconnection.

  7. Effects of electron inertia in collisionless magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Andrés, Nahuel; Martin, Luis; Dmitruk, Pablo; Gómez, Daniel

    2014-07-01

    We present a study of collisionless magnetic reconnection within the framework of full two-fluid MHD for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure and electron inertia. We performed 2.5D simulations using a pseudo-spectral code with no dissipative effects. We check that the ideal invariants of the problem are conserved down to round-off errors. Our numerical results confirm that the change in the topology of the magnetic field lines is exclusively due to the presence of electron inertia. The computed reconnection rates remain a fair fraction of the Alfvén velocity, which therefore qualifies as fast reconnection.

  8. Dynamic moments of inertia in Xe, Cs and Ba nuclei

    SciTech Connect

    El-Samman, H.; Barci, V.; Gizon, A.; Gizon, J.; Hildingsson, L.; Jerrestam, D.; Klamra, W.; Kossakowski, R.; Lindblad, T.; Gono, Y.; Bengtsson, T.; Leander, G.A.

    1984-01-01

    The ..gamma..-rays following the reactions induced by /sup 12/C ions on /sup 115/In, /sup 112/,/sup 117/,/sup 122/Sn and /sup 123/Sb targets have been investigated using six NaI(Tl) detectors in a two-dimensional arrangement. The collective moment of inertia I(/sup 2/) /sub band/ of /sup 118/,/sup 122/Xe, /sup 123/Cs and /sup 128/,/sup 130/Ba have been extracted from the energy-correlation spectra. The behaviour of these nuclei and the observed differences are interpreted in terms of high-spin collective properties. Data are also presented on the effective moment of inertia I(/sup 2/)/sub eff/ of /sup 118/Xe and /sup 130/Ba measured by sum-spectrometer techniques. 13 references.

  9. Cloud condensation nucleus-sulfate mass relationship and cloud albedo

    NASA Technical Reports Server (NTRS)

    Hegg, Dean A.

    1994-01-01

    Analysis of previously published, simultaneous measurements of cloud condensation nucleus number concentration and sulfate mass concentration suggest a nonlinear relationship between the two variables. This nonlinearity reduces the sensitivity of cloud albedo to changes in the sulfur cycle.

  10. Disappearance of the Propontis Regional Dark Albedo Feature on Mars

    NASA Astrophysics Data System (ADS)

    Lee, S. W.; Thomas, P. C.; Cantor, B. A.

    2014-07-01

    In Aug. 2009, repeated local dust storms deposited sufficient bright dust to reduce the contrast of the Propontis dark albedo feature dramatically — effectively “erasing” this distinct and long-observed feature. Propontis has yet to "recover".

  11. Interpretation of surface and planetary directional albedos for vegetated regions

    NASA Technical Reports Server (NTRS)

    Cess, Robert D.; Vulis, Inna L.

    1989-01-01

    An atmospheric solar radiation model has been coupled with surface reflectance measurements for two vegetation types, pasture land and savannah, in order to address several issues associated with understanding the directional planetary albedo; i.e., the dependence of planetary albedo upon solar zenith angle. These include an elucidation of processes that influence the variation of planetary albedo with solar zenith angle, as well as emphasizing potential problems associated with converting narrowband planetary albedo measurements to broadband quantities. It is suggested that, for vegetated surfaces, this latter task could be somewhat formidable, since the model simulations indicate that narrowband to broadband conversions strongly depend upon vegetation type. A further aspect of this paper is to illustrate a procedure by which reciprocity inconsistencies within a bidirectional reflectance dataset, if they are not too severe, can be circumvented.

  12. Greenland ice sheet albedo variability and feedback: 2000-2015

    NASA Astrophysics Data System (ADS)

    Box, J. E.; van As, D.; Fausto, R. S.; Mottram, R.; Langen, P. P.; Steffen, K.

    2015-12-01

    Absorbed solar irradiance represents the dominant source of surface melt energy for Greenland ice. Surface melting has increased as part of a positive feedback amplifier due to surface darkening. The 16 most recent summers of observations from the NASA MODIS sensor indicate a darkening exceeding 6% in July when most melting occurs. Without the darkening, the increase in surface melting would be roughly half as large. A minority of the albedo decline signal may be from sensor degradation. So, in this study, MOD10A1 and MCD43 albedo products from MODIS are evaluated for sensor degradation and anisotropic reflectance errors. Errors are minimized through calibration to GC-Net and PROMICE Greenland snow and ice ground control data. The seasonal and spatial variability in Greenland snow and ice albedo over a 16 year period is presented, including quantifying changing absorbed solar irradiance and melt enhancement due to albedo feedback using the DMI HIRHAM5 5 km model.

  13. A preliminary global oceanic cloud climatology from satellite albedo observations

    NASA Technical Reports Server (NTRS)

    Hughes, N. A.; Henderson-Sellers, A.

    1983-01-01

    A predictive relationship is developed between over-ocean cloud system albedo and the cloud amount present, using as a data base ERB satellite microwave readings at 0.5-0.7 micron and the USAF three-dimensional nephanalysis archive. The ERB data provided global coverage at a resolution of 2.5 x 2.5 deg during the 1974-78 period. Regression analyses were performed on the amounts and albedos for several years of data for one month in order to detect seasonal variations. A logarithmic relationship was found between the cloud system albedo and cloud amount over the oceans, with negligible seasonal variance. The analysis is noted to apply only where low surface albedos are encountered, and further work to extend the study to continental vegetated areas is indicated.

  14. Albedo Pattern Recognition and Time-Series Analyses in Malaysia

    NASA Astrophysics Data System (ADS)

    Salleh, S. A.; Abd Latif, Z.; Mohd, W. M. N. Wan; Chan, A.

    2012-07-01

    Pattern recognition and time-series analyses will enable one to evaluate and generate predictions of specific phenomena. The albedo pattern and time-series analyses are very much useful especially in relation to climate condition monitoring. This study is conducted to seek for Malaysia albedo pattern changes. The pattern recognition and changes will be useful for variety of environmental and climate monitoring researches such as carbon budgeting and aerosol mapping. The 10 years (2000-2009) MODIS satellite images were used for the analyses and interpretation. These images were being processed using ERDAS Imagine remote sensing software, ArcGIS 9.3, the 6S code for atmospherical calibration and several MODIS tools (MRT, HDF2GIS, Albedo tools). There are several methods for time-series analyses were explored, this paper demonstrates trends and seasonal time-series analyses using converted HDF format MODIS MCD43A3 albedo land product. The results revealed significance changes of albedo percentages over the past 10 years and the pattern with regards to Malaysia's nebulosity index (NI) and aerosol optical depth (AOD). There is noticeable trend can be identified with regards to its maximum and minimum value of the albedo. The rise and fall of the line graph show a similar trend with regards to its daily observation. The different can be identified in term of the value or percentage of rises and falls of albedo. Thus, it can be concludes that the temporal behavior of land surface albedo in Malaysia have a uniform behaviours and effects with regards to the local monsoons. However, although the average albedo shows linear trend with nebulosity index, the pattern changes of albedo with respects to the nebulosity index indicates that there are external factors that implicates the albedo values, as the sky conditions and its diffusion plotted does not have uniform trend over the years, especially when the trend of 5 years interval is examined, 2000 shows high negative linear

  15. Effect of electron inertia in two-fluid magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Gomez, Daniel; Dmitruk, Pablo; Andrés, Nahuel

    2016-07-01

    In space plasmas, magnetic reconnection is an important energy conversion process. Within the traditional one-fluid resistive MHD description, the Sweet-Parker model leads to extremely low reconnection rates for virtually all space physics applications. Within the theoretical framework of two-fluid MHD, we retain the effects of the Hall current and electron inertia and neglect dissipative effects such as viscosity and electric resistivity. This description brings two new spatial scales into play, such as the ion and electron inertial lengths. In absence of resistive dissipation, reconnection can only be attained by the action of electron inertia. We performed two-fluid simulations using a pseudo-spectral code which yields exact conservation (to round-off errors) of the ideal invariants. Our simulations show that when the effects of electron inertia are retained, magnetic reconnection takes place. Moreover, in a stationary regime the reconnection rate is simply proportional to the ion inertial length, as also emerges from a scaling law derived from dimensional arguments.

  16. Testing and Validation of the Dynamic Inertia Measurement Method

    NASA Technical Reports Server (NTRS)

    Chin, Alexander W.; Herrera, Claudia Y.; Spivey, Natalie D.; Fladung, William A.; Cloutier, David

    2015-01-01

    The Dynamic Inertia Measurement (DIM) method uses a ground vibration test setup to determine the mass properties of an object using information from frequency response functions. Most conventional mass properties testing involves using spin tables or pendulum-based swing tests, which for large aerospace vehicles becomes increasingly difficult and time-consuming, and therefore expensive, to perform. The DIM method has been validated on small test articles but has not been successfully proven on large aerospace vehicles. In response, the National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) conducted mass properties testing on an "iron bird" test article that is comparable in mass and scale to a fighter-type aircraft. The simple two-I-beam design of the "iron bird" was selected to ensure accurate analytical mass properties. Traditional swing testing was also performed to compare the level of effort, amount of resources, and quality of data with the DIM method. The DIM test showed favorable results for the center of gravity and moments of inertia; however, the products of inertia showed disagreement with analytical predictions.

  17. A neutron Albedo system with time rejection for landmine and IED detection

    NASA Astrophysics Data System (ADS)

    Kovaltchouk, V. D.; Andrews, H. R.; Clifford, E. T. H.; Faust, A. A.; Ing, H.; McFee, J. E.

    2011-10-01

    A neutron Albedo system has been developed for imaging of buried landmines and improvised explosive devices (IEDs). It involves irradiating the ground with fast neutrons and subsequently detecting the thermalized neutrons that return. A scintillating 6Li loaded ZnS(Ag) screen with a sensitive area of 40 cm×40 cm is used as a thermal neutron detector. Scintillation light is captured by orthogonal arrays of wavelength-shifting fibers placed on either side of the scintillator surface and then transferred to X and Y multi-pixel PMTs. A timing circuit, used with pulsed neutron sources, records the time when a neutron detection takes place relative to an external synchronization pulse from the pulsed source. Experimental tests of the Albedo system performance have been done in a sand box with a 252Cf neutron source (no time gating) and with pulsed D-D (2.6 MeV) neutrons from the Defense R&D Ottawa Van de Graaff accelerator (with time gating). Information contained in the time evolution of the thermal neutron field provided improved detection capability and image reconstruction. The detector design is described and experimental results are discussed.

  18. Earth albedo effects in the motion of artificial earth satellites

    NASA Astrophysics Data System (ADS)

    Lala, P.

    Different models of the earth albedo values and geographical distribution are compared. Effects of the local cloud cover on the satellite perturbing acceleration are investigated. Resulting changes of the satellite orbit obtained by the method of numerical integration in the spherical coordinate system are given. It is shown that a sufficiently sensitive microaccelerometer on board a special satellite could significantly improve existing models of the earth albedo.

  19. NEOWISE Diameters and Albedos V1.0

    NASA Astrophysics Data System (ADS)

    Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; Nugent, C. R.; Sonnett, S. M.; Stevenson, R. A.; Wright, E. L.

    2016-06-01

    This PDS data set represents a compilation of published diameters, optical albedos, near-infrared albedos, and beaming parameters for minor planets detected by NEOWISE during the fully cryogenic, 3-band cryo, post-cryo and NEOWISE-Reactivation Year 1 operations. It contains data covering near-Earth asteroids, Main Belt asteroids, active Main Belt objects, Hildas, Jupiter Trojans, Centaurs, and Jovian and Saturnian irregular satellites. Methodology for physical property determination is described in the referenced articles.

  20. IAU nomenclature for albedo features on the planet Mercury

    NASA Technical Reports Server (NTRS)

    Dollfus, A.; Chapman, C. R.; Davies, M. E.; Gingerich, O.; Goldstein, R.; Guest, J.; Morrison, D.; Smith, B. A.

    1978-01-01

    The International Astronomical Union has endorsed a nomenclature for the albedo features on Mercury. Designations are based upon the mythological names related to the god Hermes; they are expressed in Latin form. The dark-hued albedo features are associated with the generic term Solitudo. The light-hued areas are designated by a single name without generic term. The 32 names adopted are allocated on the Mercury map.

  1. Improving modeled snow albedo estimates during the spring melt season

    NASA Astrophysics Data System (ADS)

    Malik, M. Jahanzeb; Velde, Rogier; Vekerdy, Zoltan; Su, Zhongbo

    2014-06-01

    Snow albedo influences snow-covered land energy and water budgets and is thus an important variable for energy and water fluxes calculations. Here, we quantify the performance of the three existing snow albedo parameterizations under alpine, tundra, and prairie snow conditions when implemented in the Noah land surface model (LSM)—Noah's default and ones from the Biosphere-Atmosphere Transfer Scheme (BATS) and the Canadian Land Surface Scheme (CLASS) LSMs. The Noah LSM is forced with and its output is evaluated using in situ measurements from seven sites in U.S. and France. Comparison of the snow albedo simulations with the in situ measurements reveals that the three parameterizations overestimate snow albedo during springtime. An alternative snow albedo parameterization is introduced that adopts the shape of the variogram for the optically thick snowpacks and decreases the albedo further for optically thin conditions by mixing the snow with the land surface (background) albedo as a function of snow depth. In comparison with the in situ measurements, the new parameterization improves albedo simulation of the alpine and tundra snowpacks and positively impacts the simulation of snow depth, snowmelt rate, and upward shortwave radiation. An improved model performance with the variogram-shaped parameterization can, however, not be unambiguously detected for prairie snowpacks, which may be attributed to uncertainties associated with the simulation of snow density. An assessment of the model performance for the Upper Colorado River Basin highlights that with the variogram-shaped parameterization Noah simulates more evapotranspiration and larger runoff peaks in Spring, whereas the Summer runoff is lower.

  2. Simultaneous Spectral Albedo Measurements Near the Atmospheric Radiation Measurement Southern Great Plains (ARM SGP) Central Facility

    SciTech Connect

    Michalsky, Joseph J.; Min, Qilong; Barnard, James C.; Marchand, Roger T.; Pilewskie, Peter

    2003-04-30

    In this study, a data analysis is performed to determine the area-averaged, spectral albedo at ARM's SGP central facility site. The spectral albedo is then fed into radiation transfer models to show that the diffuse discrepancy is diminished when the spectral albedo is used (as opposed to using the broadband albedo).

  3. Spectral albedo and transmittance of thin young Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Taskjelle, Torbjørn; Hudson, Stephen R.; Granskog, Mats A.; Nicolaus, Marcel; Lei, Ruibo; Gerland, Sebastian; Stamnes, Jakob J.; Hamre, Børge

    2016-01-01

    Spectral albedo and transmittance in the range were measured on three separate dates on less than thick new Arctic sea ice growing on Kongsfjorden, Svalbard at , . Inherent optical properties, including absorption coefficients of particulate and dissolved material, were obtained from ice samples and fed into a radiative transfer model, which was used to analyze spectral albedo and transmittance and to study the influence of clouds and snow on these. Integrated albedo and transmittance for photosynthetically active radiation () were in the range 0.17-0.21 and 0.77-0.86, respectively. The average albedo and transmittance of the total solar radiation energy were 0.16 and 0.51, respectively. Values inferred from the model indicate that the ice contained possibly up to 40% brine and only 0.6% bubbles. Angular redistribution of solar radiation by clouds and snow was found to influence both the wavelength-integrated value and the spectral shape of albedo and transmittance. In particular, local peaks and depressions in the spectral albedo and spectral transmittance were found for wavelengths within atmospheric absorption bands. Simulated and measured transmittance spectra were within 5% for most of the wavelength range, but deviated up to 25% in the vicinity of , indicating the need for more optical laboratory measurements of pure ice, or improved modeling of brine optical properties in this near-infrared wavelength region.

  4. Postfire influences of snag attrition on albedo and radiative forcing

    NASA Astrophysics Data System (ADS)

    O'Halloran, Thomas L.; Acker, Steven A.; Joerger, Verena M.; Kertis, Jane; Law, Beverly E.

    2014-12-01

    This paper examines albedo perturbation and radiative forcing after a high-severity fire in a mature forest in the Oregon Cascade Range. Correlations between postfire albedo and seedling, sapling, and snag (standing dead tree) density were investigated across fire severity classes and seasons for years 4-15 after fire. Albedo perturbation was 14 times larger in winter compared to summer and increased with fire severity class for the first several years. Albedo perturbation increased linearly with time over the study period. Correlations between albedo perturbations and the vegetation densities were strongest with snags, and significant in all fire classes in both summer and winter (R < -0.92, p < 0.01). The resulting annual radiative forcing at the top of the atmosphere became more negative linearly at a rate of -0.86 W m-2 yr-1, reaching -15 W m-2 in year 15 after fire. This suggests that snags can be the dominant controller of postfire albedo on decadal time scales.

  5. Albedo as a modulator of climate response to tropical deforestation

    NASA Technical Reports Server (NTRS)

    Dirmeyer, Paul A.; Shukla, J.

    1994-01-01

    An atmospheric general circulation model with land surface properties represented by the simplified Simple Biosphere model is used to investigate the effects on local climate due to tropical deforestation for the Amazon basin. One control and three anomaly integrations of 4 years' duration are performed. In the anomaly integrations, rain forest in South America is replaced by degraded grassland. The anomaly integrations differ only in the optical properties of the grassland vegetation, with net surface albedos ranging from the same as to 0.09 lighter than that of rain forest. It is found that the change in climate, particularly rainfall, is strongly dependent on the change in surface albedo that accompanies deforestation. Replacement of forest by grass causes a reduction in transpiration and reduces frictional convergence by decreasing surface roughness. However, precipitation averaged over the deforested area is not necessarily reduced. Average precipitation decreases when the increase in albedo is greater than 0.03. If surface albedo is not increased appreciably as a result of deforestation, moisture flux convergence driven by the increase in surface temperature can offset the other effects, and average precipitation increases. As albedo is increased, surface temperature does not change, but surface latent and sensible heat flux decreases due to reduced radiational energy absorbed at the surface, resulting in a reduction in convection and precipitation. A change in the distribution of precipitation due to deforestation that appears to be independent of the albedo is observed.

  6. Albedo as a modulator of climate response to tropical deforestation

    SciTech Connect

    Dirmeyer, P.A.; Shukla, J.

    1994-10-01

    An atmospheric general circulation model with land surface properties represented by the simplified Simple Biosphere model is used to investigate the effects on local climate due to tropical deforestation for the Amazon basin. One control and three anomaly integrations of 4 years` duration are performed. In the anomaly integrations, rain forest in South America is replaced by degraded grassland. The anomaly integrations differ only in the optical properties of the grassland vegetation, with net surface albedos ranging from the same as to 0.09 lighter than that of rain forest. It is found that the change in climate, particularly rainfall, is strongly dependent on the change in surface albedo that accompanies deforestation. Replacement of forest by grass causes a reduction in transpiration and reduces frictional convergence by decreasing surface roughness. However, precipitation averaged over the deforested area is not necessarily reduced. Average precipitation decreases when the increase in albedo is greater than 0.03. If surface albedo is not increased appreciably as a result of deforestation, moisture flux convergence driven by the increase in surface temperature can offset the other effects, and average precipitation increases. As albedo is increased, surface temperature does not change, but surface latent and sensible heat flux decreases due to reduced radiational energy absorbed at the surface, resulting in a reduction in convection and precipitation. A change in the distribution of precipitation due to deforestation that appears to be independent of the albedo is observed.

  7. Single Scattering Albedo Monitor for Airborne Particulates

    NASA Astrophysics Data System (ADS)

    Onasch, Timothy; Massoli, Paola; Kebabian, Paul; Hills, Frank; Bacon, Fred; Freedman, Andrew

    2015-04-01

    We describe a robust, compact, field deployable instrument (the CAPS PMssa) that simultaneously measures airborne particle light extinction and scattering coefficients and thus the single scattering albedo (SSA) on the same sample volume. With an appropriate change in mirrors and light source, measurements have been made at wavelengths ranging from 450 to 780 nm. The extinction measurement is based on cavity attenuated phase shift (CAPS) techniques as employed in the CAPS PMex particle extinction monitor; scattering is measured using a integrating nephelometry by incorporating a Lambertian integrating sphere within the sample cell. The scattering measurement is calibrated using the extinction measurement. Measurements using ammonium sulfate particles of various sizes indicate that the response of the scattering channel with respect to measured extinction is linear to within 1% up to 1000 Mm-1 and can be extended further (4000 Mm-1) with additional corrections. The precision in both measurement channels is less than 1 Mm-1 (1s, 1σ). The truncation effect in the scattering channel, caused by light lost at extreme forward/backward scattering angles, was measured as a function of particle size using monodisperse polystyrene latex particles (n=1.59). The results were successfully fit using a simple geometric model allowing for reasonable extrapolation to a given wavelength, particle index of refraction and particle size distribution, assuming spherical particles. For sub-micron sized particles, the truncation corrections are comparable to those reported for commercial nephelometers. Measurements of the optical properties of ambient aerosol indicate that the values of the SSA of these particles measured with this instrument (0.91±0.03) using scattering and extinction agreed within experimental uncertainty with those determined using extinction measured by this instrument and absorption measured using a Multi-Angle Absorption Spectrometer (0.89±0.03) where the

  8. High-albedo materials for reducing building cooling energy use

    SciTech Connect

    Taha, H.; Sailor, D.; Akbari, H.

    1992-01-01

    One simple and effective way to mitigate urban heat islands, i.e., the higher temperatures in cities compared to those of the surrounds, and their negative impacts on cooling energy consumption is to use high-albedo materials on major urban surfaces such as rooftops, streets, sidewalks, school yards, and the exposed surfaces of parking lots. High-albedo materials can save cooling energy use by directly reducing the heat gain through a building`s envelope (direct effect) and also by lowering the urban air temperature in the neighborhood of the building (indirect effect). This project is an attempt to address high-albedo materials for buildings and to perform measurements of roof coatings. We search for existing methods and materials to implement fighter colors on major building and urban surfaces. Their cost effectiveness are examined and the possible related technical, maintenance, and environmental problems are identified. We develop a method for measuring albedo in the field by studying the instrumentation aspects of such measurements. The surface temperature impacts of various albedo/materials in the actual outdoor environment are studied by measuring the surface temperatures of a variety of materials tested on an actual roof. We also generate an albedo database for several urban surfaces to serve as a reference for future use. The results indicate that high-albedo materials can have a large impact on the surface temperature regime. On clear sunny days, when the solar noon surface temperatures of conventional roofing materials were about 40{degrees}C (72{degrees}F) warmer than air, the surface temperature of high-albedo coatings were only about 5{degrees}C warmer than air. In the morning and in the late afternoon, the high-albedo materials were as cool as the air itself. While conventional roofing materials warm up by an average 0.055{degrees}C/(W m{sup {minus}2}), the high-albedo surfaces warm up by an average 0.015{degrees}C/(W m{sup {minus}2}).

  9. High-albedo materials for reducing building cooling energy use

    SciTech Connect

    Taha, H.; Sailor, D.; Akbari, H.

    1992-01-01

    One simple and effective way to mitigate urban heat islands, i.e., the higher temperatures in cities compared to those of the surrounds, and their negative impacts on cooling energy consumption is to use high-albedo materials on major urban surfaces such as rooftops, streets, sidewalks, school yards, and the exposed surfaces of parking lots. High-albedo materials can save cooling energy use by directly reducing the heat gain through a building's envelope (direct effect) and also by lowering the urban air temperature in the neighborhood of the building (indirect effect). This project is an attempt to address high-albedo materials for buildings and to perform measurements of roof coatings. We search for existing methods and materials to implement fighter colors on major building and urban surfaces. Their cost effectiveness are examined and the possible related technical, maintenance, and environmental problems are identified. We develop a method for measuring albedo in the field by studying the instrumentation aspects of such measurements. The surface temperature impacts of various albedo/materials in the actual outdoor environment are studied by measuring the surface temperatures of a variety of materials tested on an actual roof. We also generate an albedo database for several urban surfaces to serve as a reference for future use. The results indicate that high-albedo materials can have a large impact on the surface temperature regime. On clear sunny days, when the solar noon surface temperatures of conventional roofing materials were about 40{degrees}C (72{degrees}F) warmer than air, the surface temperature of high-albedo coatings were only about 5{degrees}C warmer than air. In the morning and in the late afternoon, the high-albedo materials were as cool as the air itself. While conventional roofing materials warm up by an average 0.055{degrees}C/(W m{sup {minus}2}), the high-albedo surfaces warm up by an average 0.015{degrees}C/(W m{sup {minus}2}).

  10. Standards for the validation of remotely sensed albedo products

    NASA Astrophysics Data System (ADS)

    Adams, Jennifer

    2015-04-01

    Land surface albedo is important component of the Earth's energy balance, defined as the fraction of shortwave radiation absorbed by a surface, and is one many Essential Climate Variables (ECVS) that can be retrieved from space through remote sensing. To quantify the accuracy of these products, they must be validated with respect to in-situ measurements of albedo using an albedometer. Whilst accepted standards exist for the calibration of albedometers, standards for the use of in-situ measurement schemes, and their use in validation procedures have yet to be developed. It is essential that we can assess the quality of remotely sensed albedo data, and to identify traceable sources of uncertainty during process of providing these data. As a result of the current lack of accepted standards for in-situ albedo retrieval and validation procedures, we are not yet able to identify and quantify traceable sources of uncertainty. Establishing standard protocols for in-situ retrievals for the validation of global albedo products would allow inter-product use and comparison, in addition to product standardization. Accordingly, this study aims to assess the quality of in-situ albedo retrieval schemes and identify sources of uncertainty, specifically in vegetation environments. A 3D Monte Carlo Ray Tracing Model will be used to simulate albedometer instruments in complex 3D vegetation canopies. To determine sources of uncertainty, factors that influence albedo measurement uncertainty were identified and will subsequently be examined: 1. Time of day (Solar Zenith Angle) 2. Ecosytem type 3. Placement of albedometer within the ecosystem 4. Height of albedometer above the canopy 5. Clustering within the ecosystem A variety of 3D vegetation canopies have been generated to cover the main ecosystems found globally, different seasons, and different plant distributions. Canopies generated include birchstand and pinestand forests for summer and winter, savanna, shrubland, cropland and

  11. The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (<5 pr-micrometer) is observed at middle and high latitudes in the fall and winter of both hemispheres. There are large differences in the hemispheric (north versus south) and seasonal (perihelion versus aphelion) behavior of water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

  12. Preferential cooling of hot extremes from cropland albedo management

    PubMed Central

    Davin, Edouard L.; Seneviratne, Sonia I.; Ciais, Philippe; Olioso, Albert; Wang, Tao

    2014-01-01

    Changes in agricultural practices are considered a possible option to mitigate climate change. In particular, reducing or suppressing tillage (no-till) may have the potential to sequester carbon in soils, which could help slow global warming. On the other hand, such practices also have a direct effect on regional climate by altering the physical properties of the land surface. These biogeophysical effects, however, are still poorly known. Here we show that no-till management increases the surface albedo of croplands in summer and that the resulting cooling effect is amplified during hot extremes, thus attenuating peak temperatures reached during heat waves. Using a regional climate model accounting for the observed effects of no-till farming on surface albedo, as well as possible reductions in soil evaporation, we investigate the potential consequences of a full conversion to no-till agriculture in Europe. We find that the summer cooling from cropland albedo increase is strongly amplified during hot summer days, when surface albedo has more impact on the Earth’s radiative balance due to clear-sky conditions. The reduced evaporation associated with the crop residue cover tends to counteract the albedo-induced cooling, but during hot days the albedo effect is the dominating factor. For heatwave summer days the local cooling effect gained from no-till practice is of the order of 2 °C. The identified asymmetric impact of surface albedo change on summer temperature opens new avenues for climate-engineering measures targeting high-impact events rather than mean climate properties. PMID:24958872

  13. Preferential cooling of hot extremes from cropland albedo management.

    PubMed

    Davin, Edouard L; Seneviratne, Sonia I; Ciais, Philippe; Olioso, Albert; Wang, Tao

    2014-07-01

    Changes in agricultural practices are considered a possible option to mitigate climate change. In particular, reducing or suppressing tillage (no-till) may have the potential to sequester carbon in soils, which could help slow global warming. On the other hand, such practices also have a direct effect on regional climate by altering the physical properties of the land surface. These biogeophysical effects, however, are still poorly known. Here we show that no-till management increases the surface albedo of croplands in summer and that the resulting cooling effect is amplified during hot extremes, thus attenuating peak temperatures reached during heat waves. Using a regional climate model accounting for the observed effects of no-till farming on surface albedo, as well as possible reductions in soil evaporation, we investigate the potential consequences of a full conversion to no-till agriculture in Europe. We find that the summer cooling from cropland albedo increase is strongly amplified during hot summer days, when surface albedo has more impact on the Earth's radiative balance due to clear-sky conditions. The reduced evaporation associated with the crop residue cover tends to counteract the albedo-induced cooling, but during hot days the albedo effect is the dominating factor. For heatwave summer days the local cooling effect gained from no-till practice is of the order of 2 °C. The identified asymmetric impact of surface albedo change on summer temperature opens new avenues for climate-engineering measures targeting high-impact events rather than mean climate properties. PMID:24958872

  14. Global Cooling: Effect of Urban Albedo on Global Temperature

    SciTech Connect

    Akbari, Hashem; Menon, Surabi; Rosenfeld, Arthur

    2007-05-22

    In many urban areas, pavements and roofs constitute over 60% of urban surfaces (roof 20-25%, pavements about 40%). The roof and the pavement albedo can be increased by about 0.25 and 0.10, respectively, resulting in a net albedo increase for urban areas of about 0.1. Many studies have demonstrated building cooling-energy savings in excess of 20% upon raising roof reflectivity from an existing 10-20% to about 60%. We estimate U.S. potential savings in excess of $1 billion (B) per year in net annual energy bills. Increasing albedo of urban surfaces can reduce the summertime urban temperature and improve the urban air quality. Increasing the urban albedo has the added benefit of reflecting more of the incoming global solar radiation and countering the effect of global warming. We estimate that increasing albedo of urban areas by 0.1 results in an increase of 3 x 10{sup -4} in Earth albedo. Using a simple global model, the change in air temperature in lowest 1.8 km of the atmosphere is estimated at 0.01K. Modelers predict a warming of about 3K in the next 60 years (0.05K/year). Change of 0.1 in urban albedo will result in 0.01K global cooling, a delay of {approx}0.2 years in global warming. This 0.2 years delay in global warming is equivalent to 10 Gt reduction in CO2 emissions.

  15. A Continental United States High Resolution NLCD Land Cover – MODIS Albedo Database to Examine Albedo and Land Cover Change Relationships

    EPA Science Inventory

    Surface albedo influences climate by affecting the amount of solar radiation that is reflected at the Earth’s surface, and surface albedo is, in turn, affected by land cover. General Circulation Models typically use modeled or prescribed albedo to assess the influence of land co...

  16. Thermal Modeling of Planetary Surfaces and Subsurfaces and its Applications to Saturnian's Satellites

    NASA Astrophysics Data System (ADS)

    Leyrat, C.; Le Gall, A. A.

    2013-12-01

    Investigating the thermal emission from airless satellites and small bodies of the solar system provides unique insights into the physical, thermal and electrical properties of their surfaces and sub-surfaces. Observations performed in the infrared, with various local times and observational geometries can be used to characterize the surface in terms of bolometric Bond albedo and thermal inertia.. At longer wavelengths, and in particular in the microwave domain, radiometers sense greater depths thus giving access to information on the subsurface. The surface roughness can be detected by measuring the self-heating at the surface of bodies. Since 2004 Saturnian's satellites have been examined in the infrared and microwave domain by the Cassini spacecraft which orbits around the giant planet. Particular attention is paid to two of these satellites: Enceladus and Iapetus. Enceladus' South pole is a geologically active area with geysers emerging from surface features called the 'Tiger stripes'. Our recent analysis of data acquired in the passive mode of the Cassini RADAR at 2cm (Le Gall et al., AGU 2012) over a region close to these " Tigre Stripes " have shown that much higher brightness temperatures than expected were recorded pointing to a geothermal anomaly in the subsurface. This anomaly could be indicative of a buried heat source, unless it is due to exotic thermal processes such as the solid-state greenhouse effect. Iapetus displays a very strong contrast of the albedo over its surface and such dichotomy may affect the thermal properties of the regolith and also the physical process, which were at the origin of this two-tone surface. We have developed a thermal model in order to improve our understanding of the measurements made by the Cassini CIRS instrument and microwave Radiometer on Enceladus and Iapetus,. The model uses NAIF/SPICE libraries to compute the total amount of flux received at any point at the surface of the satellites, during one Saturnian year

  17. Parallel algorithms and architectures for the manipulator inertia matrix

    SciTech Connect

    Amin-Javaheri, M.

    1989-01-01

    Several parallel algorithms and architectures to compute the manipulator inertia matrix in real time are proposed. An O(N) and an O(log{sub 2}N) parallel algorithm based upon recursive computation of the inertial parameters of sets of composite rigid bodies are formulated. One- and two-dimensional systolic architectures are presented to implement the O(N) parallel algorithm. A cube architecture is employed to implement the diagonal element of the inertia matrix in O(log{sub 2}N) time and the upper off-diagonal elements in O(N) time. The resulting K{sub 1}O(N) + K{sub 2}O(log{sub 2}N) parallel algorithm is more efficient for a cube network implementation. All the architectural configurations are based upon a VLSI Robotics Processor exploiting fine-grain parallelism. In evaluation all the architectural configurations, significant performance parameters such as I/O time and idle time due to processor synchronization as well as CPU utilization and on-chip memory size are fully included. The O(N) and O(log{sub 2}N) parallel algorithms adhere to the precedence relationships among the processors. In order to achieve a higher speedup factor; however, parallel algorithms in conjunction with Non-Strict Computational Models are devised to relax interprocess precedence, and as a result, to decrease the effective computational delays. The effectiveness of the Non-strict Computational Algorithms is verified by computer simulations, based on a PUMA 560 robot manipulator. It is demonstrated that a combination of parallel algorithms and architectures results in a very effective approach to achieve real-time response for computing the manipulator inertia matrix.

  18. Relating black carbon content to reduction of snow albedo

    NASA Astrophysics Data System (ADS)

    Brandt, R. E.; Warren, S. G.; Clarke, A. D.

    2011-12-01

    In remote snow of the Northern Hemisphere, the levels of soot pollution are in the parts-per-billion (ppb) range, where the effect on albedo is at the level of a few percent. A reduction of albedo by 1-2% is significant for climate but is difficult to detect experimentally, because snow albedo depends on several other variables. In our work to quantify the climatic effect of black carbon (BC) in snow, we therefore do not directly measure the albedo reduction. Instead, we use a two-step procedure: (1) We collect snow samples, melt and filter them, and analyze the filters spectrophotometrically for BC concentration. (2) We use the BC amount from the filter measurement, together with snow grain size, in a radiative transfer model to compute the albedo reduction. Our radiative transfer model uses the discrete ordinates algorithm DISORT 2.0. We have chosen a representative BC size distribution and optical constants, and have incorporated those of mineral dust as well. While a given mass of BC causes over an order of magnitude more snow albedo reduction compared to dust, a snowpack containing dust mutes the albedo-reducing effect of BC. Because the computed reduction of snow albedo is model-based, it requires experimental verification. We doubt that direct measurement of albedo-reduction will be feasible in nature, because of the vertical variation of both snow grain size and soot content, and because the natural soot content is small. We conclude that what is needed is an artificial snowpack, with uniform grain size and large uniform soot content (ppm not ppb), to produce a large signal on albedo. We have chosen to pursue this experiment outdoors rather than in the laboratory, for the following reasons: (1) The snowpack in the field of view is uniformly illuminated if the source of radiation is the Sun. (2) Visible radiation penetrates into the snow, so photons emerge horizontally distant from where they entered. In the limited width of a laboratory snowpack, radiation

  19. Potential effects of forest management on surface albedo

    NASA Astrophysics Data System (ADS)

    Otto, J.; Bréon, F.-M.; Schelhaas, M.-J.; Pinty, B.; Luyssaert, S.

    2012-04-01

    Currently 70% of the world's forests are managed and this figure is likely to rise due to population growth and increasing demand for wood based products. Forest management has been put forward by the Kyoto-Protocol as one of the key instruments in mitigating climate change. For temperate and boreal forests, the effects of forest management on the stand-level carbon balance are reasonably well understood, but the biophysical effects, for example through changes in the albedo, remain elusive. Following a modeling approach, we aim to quantify the variability in albedo that can be attributed to forest management through changes in canopy structure and density. The modelling approach chains three separate models: (1) a forest gap model to describe stand dynamics, (2) a Monte-Carlo model to estimate the probability density function of the optical path length of photons through the canopy and (3) a physically-based canopy transfer model to estimate the interaction between photons and leaves. The forest gap model provides, on a monthly time step the position, height, diameter, crown size and leaf area index of individual trees. The Monte-Carlo model computes from this the probability density function of the distance a photon travels through crown volumes to determine the direct light reaching the forest floor. This information is needed by the canopy transfer model to calculate the effective leaf area index - a quantity that allows it to correctly represent a 3D process with a 1D model. Outgoing radiation is calculated as the result of multiple processes involving the scattering due to the canopy layer and the forest floor. Finally, surface albedo is computed as the ratio between incident solar radiation and calculated outgoing radiation. The study used two time series representing thinning from below of a beech and a Scots pine forest. The results show a strong temporal evolution in albedo during stand establishment followed by a relatively stable albedo once the canopy

  20. Understanding the Factors That Control Snow Albedo Over Central Greenland

    NASA Astrophysics Data System (ADS)

    Wright, P.; Bergin, M. H.; Dibb, J. E.; Domine, F.; Carmagnola, C.; Courville, Z.; Sokolik, I. N.; Lefer, B. L.

    2011-12-01

    Snow albedo plays a critical role in the energy balance of the Greenland Ice Sheet. In particular, the snow albedo influences the extent to which absorbing aerosols over Greenland (i.e. dust and black carbon) force climate. With this in mind the spectral snow albedo, physical snow properties, and snow chemistry were measured during May, June, and July 2011 at Summit, Greenland to investigate the variability in snow spectral albedo and its impact on aerosol direct radiative forcing. Optical and chemical properties of aerosol and aerosol optical depth were also measured as part of this study. Strellis et. al. will present a preliminary assessment of aerosol radiative forcing at Summit in summer 2011, in a separate presentation at this meeting. Spectral albedo was measured from 350-2500 nm with an ASD FieldSpec Pro spectroradiometer daily at four permanent sites and a moving fifth site where snow was sampled for characterization, as well as in more intensive diurnal and spatial surveys. Snow specific surface area (SSA), the ratio of snow crystal surface area to mass, was measured with a Dual Frequency Integrating Sphere (DUFISSS) at 1310 nm and 1550 nm, as well as with dyed and cast samples collected for stereology analysis. Snow stratigraphy, crystal size, and density were also measured on a daily basis, and snow samples will be analyzed for microstructural parameters determined from micro-CT imaging. Snow chemistry measurements include specific elements, major ions, and elemental and organic carbon. The time series of daily albedo measurements ranged from 0.88 to nearly 1.0 in visible wavelengths and from 0.42 to 0.65 in the near infrared. Changes as large as 0.1 were observed between consecutive daily measurements across the spectrum. Preliminary results show a strong correlation between variation in albedo and co-located measurements of snow specific surface area, specifically in the near infrared. By conducting our measurements near solar noon every day, and

  1. A Novel Approach to Treating Morning Sleep Inertia in Narcolepsy

    PubMed Central

    Bagai, Kanika; Malow, Beth A.

    2010-01-01

    We describe an adolescent with narcolepsy who presented with inability to awaken from sleep to attend early morning classes at school. After he did not respond to traditional therapies, a nicotine patch was prescribed with success. We present our experience with this unconventional treatment, which may benefit others with inability to awaken from sleep that is refractory to standard treatments. Citation: Bagai K; Malow BA. A novel approach to treating morning sleep inertia in narcolepsy. J Clin Sleep Med 2010;6(1):77-78. PMID:20191943

  2. An object oriented implementation of the Yeadon human inertia model

    PubMed Central

    Dembia, Christopher; Moore, Jason K.; Hubbard, Mont

    2015-01-01

    We present an open source software implementation of a popular mathematical method developed by M.R. Yeadon for calculating the body and segment inertia parameters of a human body. The software is written in a high level open source language and provides three interfaces for manipulating the data and the model: a Python API, a command-line user interface, and a graphical user interface. Thus the software can fit into various data processing pipelines and requires only simple geometrical measures as input. PMID:25717365

  3. Inertia effects in thin film flow with a corrugated boundary

    NASA Technical Reports Server (NTRS)

    Serbetci, Ilter; Tichy, John A.

    1991-01-01

    An analytical solution is presented for two-dimensional, incompressible film flow between a sinusoidally grooved (or rough) surface and a flat-surface. The upper grooved surface is stationary whereas the lower, smooth surface moves with a constant speed. The Navier-Stokes equations were solved employing both mapping techniques and perturbation expansions. Due to the inclusion of the inertia effects, a different pressure distribution is obtained than predicted by the classical lubrication theory. In particular, the amplitude of the pressure distribution of the classical lubrication theory is found to be in error by over 100 perent (for modified Reynolds number of 3-4).

  4. Occurrence of lower cloud albedo in ship tracks

    NASA Astrophysics Data System (ADS)

    Chen, Y.-C.; Christensen, M. W.; Xue, L.; Sorooshian, A.; Stephens, G. L.; Rasmussen, R. M.; Seinfeld, J. H.

    2012-05-01

    The concept of geoengineering by marine cloud brightening is based on seeding marine stratocumulus clouds with sub-micrometer sea-salt particles to enhance the cloud droplet number concentration and cloud albedo, thereby producing a climate cooling effect. The efficacy of this as a strategy for global cooling rests on the extent to which aerosol-perturbed marine clouds will respond with increased albedo. Ship tracks, cloud regions impacted by ship exhaust, are a well-known manifestation of the effect of aerosol injection on marine clouds. We present here an analysis of the albedo responses in ship tracks, based on in situ aircraft measurements and three years of satellite observations of 589 individual ship tracks. It is found that the sign (increase or decrease) and magnitude of the albedo response in ship tracks depends on the mesoscale cloud structure, the free tropospheric humidity, and cloud top height. In a closed cell structure (cloud cells ringed by a perimeter of clear air), nearly 30% of ship tracks exhibited a decreased albedo. Detailed cloud responses must be accounted for in global studies of the potential efficacy of sea-spray geoengineering as a means to counteract global warming.

  5. Occurrence of lower cloud albedo in ship tracks

    NASA Astrophysics Data System (ADS)

    Chen, Y.-C.; Christensen, M. W.; Xue, L.; Sorooshian, A.; Stephens, G. L.; Rasmussen, R. M.; Seinfeld, J. H.

    2012-09-01

    The concept of geoengineering by marine cloud brightening is based on seeding marine stratocumulus clouds with sub-micrometer sea-salt particles to enhance the cloud droplet number concentration and cloud albedo, thereby producing a climate cooling effect. The efficacy of this as a strategy for global cooling rests on the extent to which aerosol-perturbed marine clouds will respond with increased albedo. Ship tracks, quasi-linear cloud features prevalent in oceanic regions impacted by ship exhaust, are a well-known manifestation of the effect of aerosol injection on marine clouds. We present here an analysis of the albedo responses in ship tracks, based on in situ aircraft measurements and three years of satellite observations of 589 individual ship tracks. It is found that the sign (increase or decrease) and magnitude of the albedo response in ship tracks depends on the mesoscale cloud structure, the free tropospheric humidity, and cloud top height. In a closed cell structure (cloud cells ringed by a perimeter of clear air), nearly 30% of ship tracks exhibited a decreased albedo. Detailed cloud responses must be accounted for in global studies of the potential efficacy of sea-spray geoengineering as a means to counteract global warming.

  6. Climate change due to anthropogenic surface albedo modification

    SciTech Connect

    Potter, G.L.; Ellsaesser, H.W.; MacCracken, M.C.; Ellis, J.S.; Luther, F.M.

    1980-02-01

    Using a statistical dynamic climate model with more realistic surface albedo changes than used in previous experiments, we have conducted a numerical experiment combining desertification of the Sahara and deforestation of the tropical rain forest. Over an area of 9 x 10/sup 6/ km/sup 2/ at 20/sup 0/N the desert albedo was increased from 0.16 to 0.35 and over 7 x 10/sup 6/ km/sup 2/ at the equator and 10/sup 0/S the rain forest albedo was increased from 0.07 to 0.16. While the most significant direct climatic responses were observed in the modified zones, high northern latitudes exhibited the greatest cooling through activation of the ice-albedo feedback process. In contrast to Sagan et al., this experiment suggests that anthropogenic modification of surface albedo over the past few thousand years has had an impact on global climate which is likely quite small and probably undetectable.

  7. Spectral surface albedo derived from GOME-2/Metop measurements

    NASA Astrophysics Data System (ADS)

    Pflug, Bringfried; Loyola, Diego

    2009-09-01

    Spectral surface albedo is an important input for GOME-2 trace gas retrievals. An algorithm was developed for estimation of spectral surface albedo from top-of-atmosphere (TOA)-radiances measured by the Global Ozone Monitoring Experiment GOME-2 flying on-board MetOp-A. The climatologically version of this algorithm estimates Minimum Lambert-Equivalent Reflectivity (MLER) for a fixed time window and can use data of many years in contrast to the Near-real time version. Accuracy of surface albedo estimated by MLER-computation increases with the amount of available data. Unfortunately, most of the large GOME pixels are partly covered by clouds, which enhance the LER-data. A plot of LER-values over cloud fraction is used within this presentation to account for this influence of clouds. This "cloud fraction plot" can be applied over all surface types. Surface albedo obtained using the "cloud fraction plot" is compared with reference surface albedo spectra and with the FRESCO climatology. There is a general good agreement; however there are also large differences for some pixels.

  8. MORSE/STORM: A generalized albedo option for Monte Carlo calculations

    SciTech Connect

    Gomes, I.C.; Stevens, P.N. )

    1991-09-01

    The advisability of using the albedo procedure for the Monte Carlo solution of deep penetration shielding problems that have ducts and other penetrations has been investigated. The use of albedo data can dramatically improve the computational efficiency of certain Monte Carlo calculations. However, the accuracy of these results may be unacceptable because of lost information during the albedo event and serious errors in the available differential albedo data. This study was done to evaluate and appropriately modify the MORSE/BREESE package, to develop new methods for generating the required albedo data, and to extend the adjoint capability to the albedo-modified calculations. Major modifications to MORSE/BREESE include an option to save for further use information that would be lost at the albedo event, an option to displace the point of emergence during an albedo event, and an option to use spatially dependent albedo data for both forward and adjoint calculations, which includes the point of emergence as a new random variable to be selected during an albedo event. The theoretical basis for using TORT-generated forward albedo information to produce adjuncton albedos was derived. The MORSE/STORM package was developed to perform both forward and adjoint modes of analysis using spatially dependent albedo data. Results obtained with MORSE/STORM for both forward and adjoint modes were compared with benchmark solutions. Excellent agreement and improved computational efficiency were achieved, demonstrating the full utilization of the albedo option in the MORSE code. 7 refs., 17 figs., 15 tabs.

  9. Effect of moment of inertia to H type vertical axis wind turbine aerodynamic performance

    NASA Astrophysics Data System (ADS)

    Yang, C. X.; Li, S. T.

    2013-12-01

    The main aerodynamic performances (out power out power coefficient torque torque coefficient and so on) of H type Vertical Axis wind Turbine (H-VAWT) which is rotating machinery will be impacted by moment of inertia. This article will use NACA0018 airfoil profile to analyze that moment of inertia through impact performance of H type VAWT by utilizing program of Matlab and theory of Double-Multiple Streamtube. The results showed that the max out power coefficient was barely impacted when moment of inertia is changed in a small area,but the lesser moment of inertia's VAWT needs a stronger wind velocity to obtain the max out power. The lesser moment of inertia's VAWT has a big out power coefficient, torque coefficient and out power before it gets to the point of max out power coefficient. Out power coefficient, torque and torque coefficient will obviously change with wind velocity increased for VAWT of the lesser moment of inertia.

  10. In the Grip of the Distant Universe: The Science of Inertia

    NASA Astrophysics Data System (ADS)

    Graneau, Peter; Graneau, Neal

    ch. 1. All matter instantaneously senses all other matter in the universe -- ch. 2. Johannes Kepler - The astronomer who coined the word inertia -- ch. 3. Free Fall - A hardly believable story of science -- ch. 4. The Cartesian interlude - a novel cosmology -- ch. 5. Newton's force of inertia - the basis of dynamics -- ch. 6. A century of consolidation - the early practitioners of Newtonian dynamics -- ch. 7. Mach's magic principle - the unique inertial system -- ch. 8. Albert Einstein - inertia obscured by gravitation -- ch. 9. Inducing inertia - an electromagnetic analogy -- ch. 10. Retarded action at a distance - a short lived misnomer -- ch. 11. Clock confusion in the 20th century - the connection between inertia and timekeeping -- ch. 12. Machian inertia and the isotropic universe - a new force law.

  11. Inertia effects on strategy updating in emergency evacuation from a room with multiple exits

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Li, Yuanzhen

    2014-03-01

    The inertia effects on strategy updating in emergency evacuation from a room with multiple exits is studied using the modified floor field model. Game theory is adopted to deal with conflict resolving process of evacuees and inertia effects are introduced in both exit choosing and conflict resolving process. From simulation results, the influences of inertia effects on the evacuation times and cooperation frequencies have been discussed. Interestingly, it can be found that inertia effects in exit choosing may lead more evacuation times, while inertia effects in conflict resolving may lead more evacuation times and higher cooperation frequencies. This study provides a new perspective to understand how the inertia of changing status quo acts on the strategy evolution in emergency circumstances.

  12. Mars Global Surveyor Thermal Emission Spectrometer experiment: Investigation description and surface science results

    USGS Publications Warehouse

    Christensen, P.R.; Bandfield, J.L.; Hamilton, V.E.; Ruff, S.W.; Kieffer, H.H.; Titus, T.N.; Malin, M.C.; Morris, R.V.; Lane, M.D.; Clark, R.L.; Jakosky, B.M.; Mellon, M.T.; Pearl, J.C.; Conrath, B.J.; Smith, M.D.; Clancy, R.T.; Kuzmin, R.O.; Roush, T.; Mehall, G.L.; Gorelick, N.; Bender, K.; Murray, K.; Dason, S.; Greene, E.; Silverman, S.; Greenfield, M.

    2001-01-01

    a detection limit of 7sim;10%; this lack of evidence for chemical weathering indicates a geologic history dominated by a cold, dry climate in which mechanical, rather than chemical, weathering was the significant form of erosion and sediment production. (5) There is no conclusive evidence for sulfate minerals at a detection limit of ???15%. The polar region has been studied with the following major conclusions: (1) Condensed CO2 has three distinct end-members, from fine-grained crystals to slab ice. (2) The growth and retreat of the polar caps observed by MGS is virtually the same as observed by Viking 12 Martian years ago. (3) Unique regions have been identified that appear to differ primarily in the grain size of CO2; one south polar region appears to remain as black slab CO2 ice throughout its sublimation. (4) Regional atmospheric dust is common in localized and regional dust storms around the margin and interior of the southern cap. Analysis of the thermophysical properties of the surface shows that (1) the spatial pattern of albedo has changed since Viking observations, (2) a unique cluster of surface materials with intermediate inertia and albedo occurs that is distinct from the previously identified low-inertia/bright and high-inertia/dark surfaces, and (3) localized patches of high-inertia material have been found in topographic lows and may have been formed by a unique set of aeolian, fluvial, or erosional processes or may be exposed bedrock. Copyright 2001 by the American Geophysical Union.

  13. The design and operation of a planet emitted and albedo radiation simulator

    NASA Technical Reports Server (NTRS)

    Sweet, G. E.; Taylor, J. T.; Abbott, I. H. A.

    1972-01-01

    A simulator is described, which provides a dynamic simulation of planetary albedo and planet-emitted thermal radiation. The simulator was designed for model tests of advanced thermal control concepts, the development of space hardware, and flight qualification of small payloads. The simulator was designed to be used in a vacuum chamber equipped with liquid nitrogen cold walls and a solar simulator. The simulator consists of two major components: a gimbaled model support system and an array of quartz infrared lamps. Tests indicate that the apparatus will satisfactorily simulate the secondary radiation on a 0.92-meter spherical body in near-earth orbits. Calculations indicate that other shapes can be accommodated without structural modifications.

  14. Cosmic Ray Albedo Proton Yield Correlated with Lunar Elemental Abundances

    NASA Astrophysics Data System (ADS)

    Wilson, J. K.; Spence, H. E.; Case, A. W.; Blake, J. B.; Golightly, M. J.; Kasper, J. C.; Looper, M. D.; Mazur, J. E.; Schwadron, N. A.; Townsend, L. W.; Zeitlin, C. J.

    2012-12-01

    High energy cosmic rays constantly bombard the lunar regolith, producing secondary "albedo" or "splash" particles like protons and neutrons, some of which escape back to space. Two lunar missions, Lunar Prospector and the Lunar Reconnaissance Orbiter (LRO), have shown that the energy distribution of albedo neutrons is modulated by the elemental composition of the lunar regolith[1-4], with reduced neutron fluxes near the lunar poles being the result of collisions with hydrogen nuclei in ice deposits[5] in permanently shadowed craters. Here we investigate an analogous phenomenon with high energy (~100 MeV) lunar albedo protons. LRO has been observing the surface and environment of the Moon since June of 2009. The CRaTER instrument (Cosmic Ray Telescope for the Effects of Radiation) on LRO is designed to characterize the lunar radiation environment and its effects on simulated human tissue. CRaTER's multiple solid-state detectors can discriminate the different elements in the galactic cosmic ray (GCR) population above ~10 MeV/nucleon, and can also distinguish between primary GCR protons arriving from deep space and albedo particles propagating up from the lunar surface. We use albedo protons with energies greater than 60 MeV to construct a cosmic ray albedo proton map of the Moon. The yield of albedo protons is proportional to the rate of lunar proton detections divided by the rate of incoming GCR detections. The map accounts for time variation in the albedo particles driven by time variations in the primary GCR population, thus revealing any true spatial variation of the albedo proton yield. Our current map is a significant improvement over the proof-of-concept map of Wilson et al.[6]. In addition to including twelve more months of CRaTER data here, we use more numerous minimum ionizing GCR protons for normalization, and we make use of all six of CRaTER's detectors to reduce contamination from spurious non-proton events in the data stream. We find find that the flux

  15. Direct determination of surface albedos from satellite imagery

    NASA Technical Reports Server (NTRS)

    Mekler, Y.; Joseph, J. H.

    1983-01-01

    An empirical method to measure the spectral surface albedo of surfaces from Landsat imagery is presented and analyzed. The empiricism in the method is due only to the fact that three parameters of the solution must be determined for each spectral photograph of an image on the basis of independently known albedos at three points. The approach is otherwise based on exact solutions of the radiative transfer equation for upwelling intensity. Application of the method allows the routine construction of spectral albedo maps from satelite imagery, without requiring detailed knowledge of the atmospheric aerosol content, as long as the optical depth is less than 0.75, and of the calibration of the satellite sensor.

  16. A new parameterization of spectral and broadband ocean surface albedo.

    PubMed

    Jin, Zhonghai; Qiao, Yanli; Wang, Yingjian; Fang, Yonghua; Yi, Weining

    2011-12-19

    A simple yet accurate parameterization of spectral and broadband ocean surface albedo has been developed. To facilitate the parameterization and its applications, the albedo is parameterized for the direct and diffuse incident radiation separately, and then each of them is further divided into two components: the contributions from surface and water, respectively. The four albedo components are independent of each other, hence, altering one will not affect the others. Such a designed parameterization scheme is flexible for any future update. Users can simply replace any of the adopted empirical formulations (e.g., the relationship between foam reflectance and wind speed) as desired without a need to change the parameterization scheme. The parameterization is validated by in situ measurements and can be easily implemented into a climate or radiative transfer model. PMID:22274228

  17. The two faces of Iapetus. [photometric and radiometric albedo observations

    NASA Technical Reports Server (NTRS)

    Morrison, D.; Jones, T. J.; Cruikshank, D. P.; Murphy, R. E.

    1975-01-01

    Radiometric and photometric observations of Iapetus are described, and a model is developed for the albedo distribution consistent with the visual light curves, color variations, and radiometric flux curve. The 20-micron infrared observations show that the radiometric variation differs by about 180 deg in phase from the visual light curve and has a peak-to-peak amplitude of about a factor of two, while the linear phase coefficient of the light curve varies, as the satellite rotates, from 0.028 to 0.068 mag/deg. Determination of the albedo distribution is described, and it is found to be characterized by a dark area covering most of the leading hemisphere, a bright trailing hemisphere, and a bright south polar cap. The radius is approximated as 800 to 850 km, and the mean geometric albedos for the light and dark faces are estimated as 0.35 and 0.07, respectively.

  18. Sample size and scene identification (cloud) - Effect on albedo

    NASA Technical Reports Server (NTRS)

    Vemury, S. K.; Stowe, L.; Jacobowitz, H.

    1984-01-01

    Scan channels on the Nimbus 7 Earth Radiation Budget instrument sample radiances from underlying earth scenes at a number of incident and scattering angles. A sampling excess toward measurements at large satellite zenith angles is noted. Also, at large satellite zenith angles, the present scheme for scene selection causes many observations to be classified as cloud, resulting in higher flux averages. Thus the combined effect of sampling bias and scene identification errors is to overestimate the computed albedo. It is shown, using a process of successive thresholding, that observations with satellite zenith angles greater than 50-60 deg lead to incorrect cloud identification. Elimination of these observations has reduced the albedo from 32.2 to 28.8 percent. This reduction is very nearly the same and in the right direction as the discrepancy between the albedoes derived from the scanner and the wide-field-of-view channels.

  19. Moon: lunar albedo for soft x-rays

    NASA Astrophysics Data System (ADS)

    Ibadov, Subhon

    2016-07-01

    Albedo of the Moon for soft X-rays (0.1-2 keV photons) is determined on the basis of the X-ray luminosity of the Moon detected and measured for the first time by orbital space telescope ROSAT in 1990. It is found that the lunar albedo for the solar soft X-rays is less than the lunar visual region albedo almost thousand times. The data allow to estimate more correctly X-ray luminosity of dusty comets like Hyakutake C/1996 B2 and Hale-Bopp C/1995 O1 due to scattering of solar soft X-rays and to reveal thus the dominant mechanism for production of X-rays in dusty comets.

  20. Cloud albedo control by cloud-top entrainment

    NASA Technical Reports Server (NTRS)

    Hanson, Howard P.

    1991-01-01

    Marine stratus and stratocumulus clouds exert a considerable influence on the earth's heat budget, mainly due to their high albedos relative to the ocean surface. It is therefore important to understand the processes that control the radiative properties of these extensive cloud systems, particularly during daylight hours. Aircraft measurements of a stratocumulus cloud deck taken around local noon during the 1987 field phase of the First International Satellite Cloud Climatology Project Regional Experiment are the topic of this paper. A mixing line analysis of data from a series of flight tracks across a strong gradient in cloud albedo provides evidence that variations in the water vapor content of the air above the marine inversion can be responsible for the albedo change. The implications of this unexpected result for climate modeling are discussed.

  1. Maximum mass, moment of inertia and compactness of relativistic stars

    NASA Astrophysics Data System (ADS)

    Breu, Cosima; Rezzolla, Luciano

    2016-06-01

    A number of recent works have highlighted that it is possible to express the properties of general-relativistic stellar equilibrium configurations in terms of functions that do not depend on the specific equation of state employed to describe matter at nuclear densities. These functions are normally referred to as `universal relations' and have been found to apply, within limits, both to static or stationary isolated stars, as well as to fully dynamical and merging binary systems. Further extending the idea that universal relations can be valid also away from stability, we show that a universal relation is exhibited also by equilibrium solutions that are not stable. In particular, the mass of rotating configurations on the turning-point line shows a universal behaviour when expressed in terms of the normalized Keplerian angular momentum. In turn, this allows us to compute the maximum mass allowed by uniform rotation, Mmax, simply in terms of the maximum mass of the non-rotating configuration, M_{_TOV}, finding that M_max ≃ (1.203 ± 0.022) M_{_TOV} for all the equations of state we have considered. We further introduce an improvement to previously published universal relations by Lattimer & Schutz between the dimensionless moment of inertia and the stellar compactness, which could provide an accurate tool to constrain the equation of state of nuclear matter when measurements of the moment of inertia become available.

  2. Micro-opto-mechanical disk for inertia sensing

    NASA Astrophysics Data System (ADS)

    Dushaq, Ghada H.; Muluget, Tadesse; Rasras, Mahmoud

    2016-03-01

    An optically enabled z-axis micro-disk inertia sensor is presented, which consists of a disk-shaped proof mass integrated on top of an optical waveguide. Numerical simulations show that the optical power of laser beam propagating in a narrow silicon nitride (Si3N4) waveguide located under the disk is attenuated in response to the vertical movement of the micro-disk. The high leakage power of the TM mode can effectively be used to detect a dynamic range of 1 g‒10 g ( g=9.8 m/s2). At lest, the waveguide is kept at a nominal gap of 1 µm from the proof mass. It is adiabatically tapered to a narrow dimension of W× H = 350×220 nm2 in a region where the optical mode is intended to interact with the proof mass. Furthermore, the bottom cladding is completely etched away to suspend the waveguide and improve the optical interaction with the proof mass. The proposed optical inertia sensor has a high sensitivity of 3 dB/ g when a 50 µm-long waveguide is used (normalized sensitivity 0.5 dB/µm2) for the vertical movement detection.

  3. Inertia dominated thin-film flows over microdecorated surfaces

    NASA Astrophysics Data System (ADS)

    Dressaire, Emilie; Courbin, Laurent; Crest, Jérome; Stone, Howard A.

    2010-07-01

    We analyze the inertia dominated flow of thin liquid films on microtextured substrates, which here are assemblies of micron-size posts arranged on regular lattices. We focus on situations for which the thin-film thickness and the roughness characteristic length scale are of the same order of magnitude, i.e., a few hundred microns. We assume that the liquid flows isotropically through the roughness at a flow rate that depends on the geometrical features of the porous layer; above the texture, the flow is characterized by a larger Reynolds number and modeled using a boundary layer approach. The influence of the microtexture on the thin-film flow above the microposts is captured by a reduction of the flow rate due to the leakage flow through the texture and a slip boundary condition, which depends on the flow direction as well as on the lattice properties. In this way, the velocity field in the free surface flow adopts the symmetry of the microtexture underneath. The results of this model are in good agreement with experimental observations obtained for thin-film flows formed upon jet impact on microtextures. The characteristics of the polygonal hydraulic jumps that we obtain depend on both the jet parameters and the topographical features of the surface roughness. We use the measurements and the numerical predictions to estimate the flow rate through the shallow porous layer and the effective slip length for this inertia dominated flow regime. We also discuss the limitations of the model.

  4. Detailed spatiotemporal albedo observations at Greenland's Mittivakkat Gletscher

    NASA Astrophysics Data System (ADS)

    Mernild, Sebastian H.; Knudsen, Niels T.; Yde, Jacob C.; Malmros, Jeppe K.

    2015-04-01

    Surface albedo is defined as the reflected fraction of incoming solar shortwave radiation at the surface. On Greenland's Mittivakkat Gletscher the mean glacier-wide MODIS-estimated albedo dropped by 0.10 (2000-2013) from 0.43 to 0.33 by the end of the mass balance year (EBY). Hand-held albedo measurements as low as 0.10 were observed over debris-covered ice at the glacier margin at the EBY: these values were slightly below observed values for proglacial bedrock (~0.2). The albedo is highly variable in space - a significant variability occurred within few meters at the glacier margin area ranging from 0.10 to 0.39 due to variability in debris-cover thickness and composition, microbial activity (including algae and cyanobacteria), snow grain crystal metamorphism, bare ice exposure, and meltwater ponding. Huge dark-red-brown-colored ice algae colonies were observed. Albedo measurements on snow patches and bare glacier ice changed significant with increasing elevations (180-600 m a.s.l.) by lapse rates of 0.04 and 0.03 per 100 m, respectively, indicating values as high as 0.82 and 0.40 on the upper part of the glacier. Over a period of two weeks from early August to late August 2014 the hand-held observed mean glacier-wide albedo changed from 0.40 to 0.30 indicating that on average 10% more incoming solar shortwave radiation became available for surface ablation at the end of the melt season.

  5. Transformation of surface albedo to surface: Atmosphere surface and irradiance, and their spectral and temporal averages

    NASA Technical Reports Server (NTRS)

    Nack, M. L.; Curran, R. J.

    1978-01-01

    The dependence of the albedo at the top of a realistic atmosphere upon the surface albedo, solar zenith angle, and cloud optical thickness is examined for the cases of clear sky, total cloud cover, and fractional cloud cover. The radiative transfer calculations of Dave and Braslau (1975) for particular values of surface albedo and solar zenith angle, and a single value of cloud optical thickness are used as the basis of a parametric albedo model. The question of spectral and temporal averages of albedos and reflected irradiances is addressed, and unique weighting functions for the spectral and temporal albedo averages are developed.

  6. Comparative global albedo and color maps of the Uranian satellites

    NASA Technical Reports Server (NTRS)

    Buratti, Bonnie J.; Mosher, Joel A.

    1991-01-01

    The surfaces of the Uranian satellites Ariel, Miranda, Oberon, Titania, and Umbriel are characterized on the basis of Voyager observations. Tables of spectrophotometric data and maps of normal reflectances, green/violet ratios, and possible geological formations are presented and discussed in detail. Variations in albedo are found to be associated with impact features, and it is inferred from color differences that the upper surface of Ariel contains a higher proportion of redder material (tentatively identified as accreted low-albedo meteoritic dust) than those of the other moons.

  7. Albedo, clouds and climate sensitivity in the CMIP3 models

    NASA Astrophysics Data System (ADS)

    Bender, F.; Rodhe, H.; Ekman, A. M.; Charlson, R.

    2010-12-01

    The albedo is a key parameter in the radiative budget of the Earth and a primary determinant of the planetary temperature and is therefore also central to questions regarding climate stability, climate change and climate sensitivity. Global climate models are essential for studying the albedo, and the parameters determining it (specifically clouds), on large spatial and temporal scales. Although models (here represented by the CMIP3 models) are able to capture the large-scale characteristics of the albedo, a bias is found between modelled and observed global albedo estimates, and on a regional scale particularly problematic regions can be identified. Many cloud parameters are poorly constrained by observations, and vary widely among models. This freedom of variability can be used in tuning models to the better constrained radiative budget, which may influence the model climate sensitivity. The effect can be kept small, compared to the range of climate sensitivities estimated by different models. Despite their different parameterizations of clouds, aerosols etc., models do have fundamental features in common, which can further the understanding of the real climate system. For instance, sensitivity to volcanic forcing is related to climate sensitivity in an ensemble of CMIP3 models. If this relation is valid for the real climate as well, observations of the volcanic sensitivity can help restrict estimates of climate sensitivity. The range of climate sensitivity estimates in models can largely be attributed to variations in cloud response to external forcing. In models with high (low) climate sensitivity, changes in cloud cover and cloud reflectivity generally enhance (counteract) a positive radiative forcing due to increased CO2 concentrations, feeding back on (damping) the warming, with a more (less) negative albedo response to the forcing. Cloud albedo is important in this regard, yet not well known. Regional cloud albedo, particularly for low-level marine

  8. Daily albedo estimation and comparison to MCD43 product

    NASA Astrophysics Data System (ADS)

    Franch, B.; Vermote, E.; Sobrino, J. A.

    2013-12-01

    Land surface broadband albedo is among the main radiative uncertainties in current climate modelling. An accuracy requirement of 5% and a daily temporal resolution is suggested by the Global Climate Observing System for albedo characterization at spatial and temporal scales compatible with climate studies. Satellite remote sensing provides the only practical way of producing high-quality global albedo data sets with high spatial and temporal resolutions. For view-ilumination geometries such as Moderate Resolution Imaging Spectroradiometer (MODIS), in order to retrieve the Bidirectional Reflectance Distribution Function (BRDF) parameters and, consequently, the albedo, a period of sequential measurement is needed to accumulate sufficient observations. This is used to derive the MODIS BRDF/Albedo product (MCD43), which consider a composite period of 16 days with a resulting temporal resolution of 8 days. Looking for an improvement in the albedo temporal resolution that mitigated the assumption of a stable target, Vermote et al. (2009) presented the VJB method that assumes that the BRDF shape variations throughout a year are limited and linked to the Normalized Difference Vegetation Index (NDVI). This method retains the highest temporal resolution (daily, cloud cover permitting). The purpose of this work is to compare the MCD43 product with the VJB method through the albedo. Additionally, we present and study a method based on the VJB assumption, the 5param Rsqr. In this study we focus our analysis on daily MODIS CMG Collection 6 data from both Aqua and Terra satellites over Europe from 2002 until 2011. Figure 1 shows the percentage of the total RMSE of the VJB and the 5param Rsqr method against the MCD43 product. They display that southern latitudes present lower errors while they increase for northern latitudes and mountainous areas. Comparing the methods, the VJB presents errors higher than 15% in 8.2% of total land pixels while they suppose 6.9% of pixels when

  9. "TNOs are Cool": A survey of the trans-Neptunian region. IV. Size/albedo characterization of 15 scattered disk and detached objects observed with Herschel-PACS

    NASA Astrophysics Data System (ADS)

    Santos-Sanz, P.; Lellouch, E.; Fornasier, S.; Kiss, C.; Pal, A.; Müller, T. G.; Vilenius, E.; Stansberry, J.; Mommert, M.; Delsanti, A.; Mueller, M.; Peixinho, N.; Henry, F.; Ortiz, J. L.; Thirouin, A.; Protopapa, S.; Duffard, R.; Szalai, N.; Lim, T.; Ejeta, C.; Hartogh, P.; Harris, A. W.; Rengel, M.

    2012-05-01

    Context. Physical characterization of trans-Neptunian objects, a primitive population of the outer solar system, may provide constraints on their formation and evolution. Aims: The goal of this work is to characterize a set of 15 scattered disk (SDOs) and detached objects, in terms of their size, albedo, and thermal properties. Methods: Thermal flux measurements obtained with the Herschel-PACS instrument at 70, 100 and 160 μm, and whenever applicable, with Spitzer-MIPS at 24 and 70 μm, are modeled with radiometric techniques, in order to derive the objects' individual size, albedo and when possible beaming factor. Error bars are obtained from a Monte-Carlo approach. We look for correlations between these and other physical and orbital parameters. Results: Diameters obtained for our sample range from 100 to 2400 km, and the geometric albedos (in V band) vary from 3.8% to 84.5%. The unweighted mean V geometric albedo for the whole sample is 11.2% (excluding Eris); 6.9% for the SDOs, and 17.0% for the detached objects (excluding Eris). We obtain new bulk densities for three binary systems: Ceto/Phorcys, Typhon/Echidna and Eris/Dysnomia. Apart from correlations clearly due to observational bias, we find significant correlations between albedo and diameter (more reflective objects being bigger), and between albedo, diameter and perihelion distance (brighter and bigger objects having larger perihelia). We discuss possible explanations for these correlations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. PACS: The Photodetector Array Camera and Spectrometer is one of Herschel's instruments.Appendices are available in electronic form at http://www.aanda.org

  10. Microstructural Characterization of Thermomechanical and Heat-Affected Zones of an Inertia Friction Welded Astroloy

    NASA Astrophysics Data System (ADS)

    Oluwasegun, K. M.; Olawale, J. O.; Ige, O. O.; Shittu, M. D.; Adeleke, A. A.; Malomo, B. O.

    2014-08-01

    The behaviour of γ' phase to thermal and mechanical effects during rapid heating of Astroloy, a powder metallurgy nickel-based superalloy has been investigated. The thermo-mechanical-affected zone (TMAZ) and heat-affected zone (HAZ) microstructures of an inertia friction welded (IFW) Astroloy were simulated using a Gleeble thermo-mechanical simulation system. Detailed microstructural examination of the simulated TMAZ and HAZ and those present in actual IFW specimens showed that γ' particles persisted during rapid heating up to a temperature where the formation of liquid is thermodynamically favored and subsequently re-solidified eutectically. The result obtained showed that forging during the thermo-mechanical simulation significantly enhanced resistance to weld liquation cracking of the alloy. This is attributable to strain-induced rapid isothermal dissolution of the constitutional liquation products within 150 μm from the center of the forged sample. This was not observed in purely thermally simulated samples. The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens.

  11. Fine-grained impact ejecta on the Moon: Views from Earth-based radar and the LRO Diviner thermal mapper

    NASA Astrophysics Data System (ADS)

    Ghent, R. R.; Koziar, J.; Paige, D. A.; Vasavada, A. R.

    2009-12-01

    The goal of this work is to use Diviner thermal mapper observations to constrain the surface block populations of fine-grained impact ejecta on the Moon. The statistical distribution of rocks in impact ejecta deposits is important because it constrains the processes by which fragmentary impact debris is produced and subsequently deposited on the surface. Earth-based radar observations have revealed meters-thick haloes of material depleted in blocks 1cm and greater in diameter, surrounding nearside impact craters. Radar observations allow characterization of the bulk properties of the upper ~10m of material, but do not yield direct information about the surface rock distribution. Diviner’s four thermal infrared channels, ranging from 12.5 to 200 microns, provide the means to investigate variations in surface thermophysical properties between impact ejecta and surrounding regolith. In this paper, we will report on comparisons between Diviner thermal infrared and Earth-based radar observations for nearside craters with radar-dark, fine-grained ejecta haloes. The brightness temperature of the lunar surface as measured by Diviner is a function of albedo, emissivity, and thermal inertia, and the bulk thermal inertia of a given mixture of soil and rocks varies with rock fraction. The resulting differences in brightness temperature are most pronounced during the night, and the particular way in which the temperature varies with rock fraction depends on the soil emissivity. The spatial resolution of the Diviner measurements (320 m / pixel) is close to that of existing 70-cm wavelength radar images (at 400 m / pixel), which facilitates comparison between the two data sets. Preliminary work indicates that radar-bright, blocky ejecta close to crater rims show higher pre-dawn brightness temperatures than either more distal fine ejecta or background regolith, and the location of the transition correlates closely between the two data sets. Current work is focused on extending

  12. Modeling the thermal emission from asteroid 3 Juno using ALMA observations and the KRC thermal model

    NASA Astrophysics Data System (ADS)

    Titus, Timothy N.; Li, Jian-Yang; Moullet, Arielle; Sykes, Mark V.

    2015-11-01

    Asteroid 3 Juno (hereafter referred to as Juno), discovered 1 September 1804, is the 11th largest asteroid in the Main Asteroid Belt (MAB). Containing approximately 1% of the mass in the MAB [1], Juno is the second largest S-type [2].As part of the observations acquired from Atacama Large Millimeter/submillimeter Array (ALMA) [3], 10 reconstructed images at ~60km/pixel resolution were acquired of Juno [4] that showed significant deviations from the Standard Thermal Model (STM) [5]. These deviations could be a result of surface topography, albedo variations, emissivity variations, thermal inertia variations, or any combination.The KRC thermal model [6, 7], which has been extensively used for Mars [e.g. 8, 9] and has been applied to Vesta [10] and Ceres [11], will be used to compare model thermal emission to that observed by ALMA at a wavelength of 1.33 mm [4]. The 10 images, acquired over a four hour period, captured ~55% of Juno’s 7.21 hour rotation. Variations in temperature as a function of local time will be used to constrain the source of the thermal emission deviations from the STM.This work is supported by the NASA Solar System Observations Program.References:[1] Pitjeva, E. V. (2005) Solar System Research 39(3), 176. [2] Baer, J. and S. R. Chesley (2008) Celestial Mechanics and Dynamical Astronomy, 100, 27-42. [3] Wootten A. et al. (2015) IAU General Assembly, Meeting #29, #2237199 [4] arXiv:1503.02650 [astro-ph.EP] doi: 10.1088/2041-8205/808/1/L2 [5] Lebofsky, L.A. eta al. (1986) Icarus, 68, 239-251. [6] Kieffer, H. H., et al. (1977) J. Geophys. Res., 82, 4249-4291. [7] Kieffer, Hugh H., (2013) Journal of Geophysical Research: Planets, Volume 118, Issue 3, pp. 451-470 [8] Titus, T. N., H. H. Kieffer, and P. N. Christensen (2003) Science, 299, 1048-1051. [9] Fergason, R. L. et al. (2012) Space Sci. Rev, 170, 739-773, doi:10.1007/s11214-012-9891-3. [10] Titus, T. N. et al. (2012) 43rd LPSC, held March 19-23, 2012 at The Woodlands, Texas. LPI Contribution No

  13. Intercomparison and interpretation of satellite-derived directional albedos over deserts

    NASA Technical Reports Server (NTRS)

    Cess, Robert D.; Vulis, Inna L.

    1989-01-01

    Issues related to the dependence of planetary albedo upon solar zenith angle are studied using Nimbus-7, GOES, and Meteosat data over deserts. Geographical variations of the planetary albedo are isolated from the albedo's solar zenith angle dependence. An atmospheric solar radiation model is coupled with desert surface bidirectional reflectance measurements to test the consistency of satellite-derived directional planetary albedos. Consideration is given to the use of narrowband versus broadband instruments, the impact of desert aerosols on the directional planetary albedo, and potential differences in the directional planetary albedo associated with different types of deserts. The results show that the directional planetary albedo is dominated by the directional surface albedo, although surface brightness influences the atmospheric limb brightening and limb darkening processes.

  14. Albedo and color maps of the Saturnian satellites

    SciTech Connect

    Buratti, B.J.; Mosher, J.A.; Johnson, T.V. )

    1990-10-01

    The paper discusses the production of maps of the albedos and colors of Mimas, Enceladus, Tethys, Dione, and Rhea over the full range of their imaged surfaces. Voyager images were used to prepare maps of the normal reflectances and color ratios (0.58/0.41 micron) of these satelites. 67 refs.

  15. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  16. Detection limits of albedo changes induced by climate engineering

    NASA Astrophysics Data System (ADS)

    Seidel, Dian J.; Feingold, Graham; Jacobson, Andrew R.; Loeb, Norman

    2014-02-01

    A key question surrounding proposals for climate engineering by increasing Earth's reflection of sunlight is the feasibility of detecting engineered albedo increases from short-duration experiments or prolonged implementation of solar-radiation management. We show that satellite observations permit detection of large increases, but interannual variability overwhelms the maximum conceivable albedo increases for some schemes. Detection of an abrupt global average albedo increase <0.002 (comparable to a ~0.7 W m-2 reduction in radiative forcing) would be unlikely within a year, given a five-year prior record. A three-month experiment in the equatorial zone (5° N-5° S), a potential target for stratospheric aerosol injection, would need to cause an ~0.03 albedo increase, three times larger than that due to the Mount Pinatubo eruption, to be detected. Detection limits for three-month experiments in 1° (latitude and longitude) regions of the subtropical Pacific, possible targets for cloud brightening, are ~0.2 larger than might be expected from some model simulations.

  17. Variable control of neutron albedo in toroidal fusion devices

    DOEpatents

    Jassby, D.L.; Micklich, B.J.

    1983-06-01

    This invention pertains to methods of controlling in the steady state, neutron albedo in toroidal fusion devices, and in particular, to methods of controlling the flux and energy distribution of collided neutrons which are incident on an outboard wall of a toroidal fusion device.

  18. Albedo in the ATIC Experiment: Results of Measurements and Simulation

    NASA Technical Reports Server (NTRS)

    Sokolskaya, N. V.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Batkov, K. E.; Chang, J.; Christl, M.; Fazely, A. R.; Ganel, O.; Gunasingha, R. M.

    2004-01-01

    Characteristics of albedo, or backscatter current, providing a 'background' for calorimeter experiments in high energy cosmic rays are analyzed. The comparison of experimental data obtained in the flights of the ATIC spectrometer is made with simulations performed using the GEANT 3.21 code. The influence of the backscatter on charge resolution in the ATIC experiment is discussed.

  19. Mimicking biochar-albedo feedback in complex Mediterranean agricultural landscapes

    NASA Astrophysics Data System (ADS)

    Bozzi, E.; Genesio, L.; Toscano, P.; Pieri, M.; Miglietta, F.

    2015-08-01

    Incorporation of charcoal produced by biomass pyrolysis (biochar) in agricultural soils is a potentially sustainable strategy for climate change mitigation. However, some side effects of large-scale biochar application need to be investigated. In particular a massive use of a low-reflecting material on large cropland areas may impact the climate via changes in surface albedo. Twelve years of MODIS-derived albedo data were analysed for three pairs of selected agricultural sites in central Italy. In each pair bright and dark coloured soil were identified, mimicking the effect of biochar application on the land surface albedo of complex agricultural landscapes. Over this period vegetation canopies never completely masked differences in background soil colour. This soil signal, expressed as an albedo difference, induced a local instantaneous radiative forcing of up to 4.7 W m-2 during periods of high solar irradiance. Biochar mitigation potential might therefore be reduced up to ˜30%. This study proves the importance of accounting for crop phenology and crop management when assessing biochar mitigation potential and provides more insights into the analysis of its environmental feedback.

  20. FLASH EXTRACTION OF PECTIN FROM ORANGE ALBEDO BY STEAM INJECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pectin was acid extracted from orange albedo by steam injection heating under pressure. Extraction times ranged from 2 to 6 minutes at a pressure of about 15 psi. Solubilized pectin was characterized by HPSEC with online light scattering and viscosity detection. Molar mass (M), radius of gyration...

  1. Detection of light transformations and concomitant changes in surface albedo

    PubMed Central

    Gerhard, Holly E.; Maloney, Laurence T.

    2010-01-01

    We report two experiments demonstrating that (1) observers are sensitive to information about changes in the light field not captured by local scene statistics and that (2) they can use this information to enhance detection of changes in surface albedo. Observers viewed scenes consisting of matte surfaces at many orientations illuminated by a collimated light source. All surfaces were achromatic, all lights neutral. In the first experiment, observers attempted to discriminate small changes in direction of the collimated light source (light transformations) from matched changes in the albedos of all surfaces (non-light transformations). Light changes and non-light changes shared the same local scene statistics and edge ratios, but the latter were not consistent with any change in direction to the collimated source. We found that observers could discriminate light changes as small as 5 degrees with sensitivity d′ > 1 and accurately judge the direction of change. In a second experiment, we measured observers' ability to detect a change in the surface albedo of an isolated surface patch during either a light change or a surface change. Observers were more accurate in detecting isolated albedo changes during light changes. Measures of sensitivity d′ were more than twice as great. PMID:20884599

  2. Using BRDFs for accurate albedo calculations and adjacency effect corrections

    SciTech Connect

    Borel, C.C.; Gerstl, S.A.W.

    1996-09-01

    In this paper the authors discuss two uses of BRDFs in remote sensing: (1) in determining the clear sky top of the atmosphere (TOA) albedo, (2) in quantifying the effect of the BRDF on the adjacency point-spread function and on atmospheric corrections. The TOA spectral albedo is an important parameter retrieved by the Multi-angle Imaging Spectro-Radiometer (MISR). Its accuracy depends mainly on how well one can model the surface BRDF for many different situations. The authors present results from an algorithm which matches several semi-empirical functions to the nine MISR measured BRFs that are then numerically integrated to yield the clear sky TOA spectral albedo in four spectral channels. They show that absolute accuracies in the albedo of better than 1% are possible for the visible and better than 2% in the near infrared channels. Using a simplified extensive radiosity model, the authors show that the shape of the adjacency point-spread function (PSF) depends on the underlying surface BRDFs. The adjacency point-spread function at a given offset (x,y) from the center pixel is given by the integral of transmission-weighted products of BRDF and scattering phase function along the line of sight.

  3. Albedo and color maps of the Saturnian satellites

    NASA Technical Reports Server (NTRS)

    Buratti, Bonnie J.; Mosher, Joel A.; Johnson, Torrence V.

    1990-01-01

    The paper discusses the production of maps of the albedos and colors of Mimas, Enceladus, Tethys, Dione, and Rhea over the full range of their imaged surfaces. Voyager images were used to prepare maps of the normal reflectances and color ratios (0.58/0.41 micron) of these satelites.

  4. Kidney organ donation: developing family practice initiatives to reverse inertia

    PubMed Central

    2010-01-01

    Background Kidney transplantation is associated with greater long term survival rates and improved quality of life compared with dialysis. Continuous growth in the number of patients with kidney failure has not been matched by an increase in the availability of kidneys for transplantation. This leads to long waiting lists, higher treatment costs and negative health outcomes. Discussion Misunderstandings, public uncertainty and issues of trust in the medical system, that limit willingness to be registered as a potential donor, could be addressed by community dissemination of information and new family practice initiatives that respond to individuals' personal beliefs and concerns regarding organ donation and transplantation. Summary Tackling both personal and public inertia on organ donation is important for any community oriented kidney donation campaign. PMID:20478042

  5. Generation and backreaction of spontaneously emitted inertia-gravity waves

    NASA Astrophysics Data System (ADS)

    Sugimoto, Norihiko; Plougonven, Riwal

    2016-04-01

    Spontaneous generation of inertia-gravity waves from balanced flows is investigated in idealized simulations of dipoles. Long integrations are performed for dipoles with different Rossby numbers (Ro) to identify the backreaction of the waves. Emission of waves is detected only for large enough Ro (>0.15), and it then leads to a slow decay of the dipole's kinetic energy. A major finding is that this decay is well captured by the simulations, although positions of the waves appear still sensitive to the resolution, and their maximum vertical velocity increases linearly with resolution. The interpretation is that the emission process is well resolved and fairly insensitive to resolution, while the propagation and dissipation at small scales remains sensitive to resolution. The implication is that the simulations yield an estimate of the leakage of energy from balanced motions to gravity waves, providing a useful estimate of a poorly constrained flux in the ocean's energy budget.

  6. An improved lunar moment of inertia determination - A proposed strategy

    NASA Technical Reports Server (NTRS)

    Ananda, M. P.; Ferrari, A. J.; Sjogren, W. L.

    1977-01-01

    A strategy for determining an improved lunar moment of inertia is proposed. An improved uncertainty in the lunar inhomogeneity parameter could reduce the core density error from 4.20 gr/cu cm to 0.1 gm/cu cm for the case of a lunar density model having a 300 km core radius. The current error of 0.0025 for the lunar inhomogeneity parameter is mostly due to the uncertainties in the C20 and C22 gravity harmonics. An optimum reduction strategy for obtaining an order of magnitude improvement in the gravity estimates is based on covariance analyses of Doppler data. The long-arc reduction method is shown to provide better results than the short-arc technique, and the use of an orbit with a 7000 km semimajor axis along with certain terms of up to degree and order eight is recommended.

  7. Effects of Roughness and Inertia on Precursors to Frictional Sliding

    NASA Astrophysics Data System (ADS)

    Robbins, Mark O.; Salerno, K. Michael

    2012-02-01

    Experiments show that when a PMMA block on a surface is normally loaded and driven by an external shear force, contact at the interface is modified in discrete precursor slips prior to steady state sliding.[1] Our simulations use an atomistic model of a rough two-dimensional block in contact with a flat surface to investigate the evolution of stress and displacement along the contact between surfaces. The talk will show how local and global stress conditions govern the initiation of interfacial cracks as well as the spatial extension of the cracked region. Inertia also plays an important role in determining the number and size of slips before sliding and influences the distribution of stresses at the interface. Finally, the geometry of surface asperities also influences the interfacial evolution and the total friction force. The relationship between the interfacial stress state and rupture velocity will also be discussed. [1] S.M. Rubinstein, G. Cohen and J. Fineberg, PRL 98, 226103 (2007)

  8. The Early Lunar Orbit and Principal Moments of Inertia

    NASA Astrophysics Data System (ADS)

    Garrick-Bethell, I.; Zuber, M. T.

    2007-12-01

    If taken at face value, the principal lunar moments of inertia suggest that the Moon froze in a past tidal and rotational state during a high eccentricity orbit [1]. At this time the Moon may have been in either synchronous rotation or in a 3:2 resonance of spin and mean motion. We have performed further investigations of the plausibility of past high eccentricity lunar orbits on the basis of orbital evolution, the dynamics of entry into any past 3:2 resonance, and tidal dissipation. We have found that the requisite permanent (B-A)/C (where A, B, and C are the principal moments of inertia) for a 3:2 resonance can be achieved in a magma ocean if a density anomaly is present shortly after lunar accretion. In a high eccentricity orbit, tidal dissipation will affect the Moon's ability to develop lithospheric strength. The Moon is presently able to support degree-two loads, while Io, which is approximately the same size as the Moon and strongly heated by tidal dissipation, probably cannot [2]. Therefore, somewhere between the present lunar radioactive heating rate (~1012 W), and Io's observed dissipation (~1014 W), the Moon may develop lithospheric strength. We use 1014 W as a loose upper bound on where freeze-in may begin and find that in a 3:2 resonance tidal dissipation [3] can drop below 1014 W at a = 25 RE and e = 0.17, and the present moments of inertia can be approximately reproduced for lunar values of QM = 475 (where a is the lunar semimajor axis, RE is the Earth radius, and Q is the specific dissipation function). This value of QM is somewhat large, but the biggest problem with a 3:2 resonance that lasts until 25 RE is how to achieve the current low eccentricity synchronous orbit. The required damping cannot be easily achieved unless the Moon is knocked out of a 3:2 resonance by an impactor that would produce a crater approximately 800 km in diameter. In sum, there is no single strong constraint that completely rules out a 3:2 resonance, but it would require a

  9. The earth's equatorial principal axes and moments of inertia

    NASA Technical Reports Server (NTRS)

    Liu, H. S.; Chao, B. F.

    1991-01-01

    The earth's equatorial principal moments of inertia are given as A and B, where A is less than B, and the corresponding principal axes are given as a and b. Explicit formulas are derived for determining the orientation of a and b axes and the difference B - A using C(22) and S(22), the two gravitational harmonic coefficients of degree 2 and order 2. For the earth, the a axis lies along the (14.93 deg W, 165.07 deg E) diameter, and the b axis lies perpendicular to it along the (75.07 deg E, 104.93 deg W) diameter. The difference B - A is 7.260 x 10 to the -6th MR2. These quantities for other planets are contrasted, and geophysical implications are discussed.

  10. Giant pulsar glitches and the inertia of neutron star crusts

    NASA Astrophysics Data System (ADS)

    Delsate, T.; Chamel, N.; Gürlebeck, N.; Fantina, A. F.; Pearson, J. M.; Ducoin, C.

    2016-07-01

    Giant pulsar frequency glitches as detected in the emblematic Vela pulsar have long been thought to be the manifestation of a neutron superfluid permeating the inner crust of a neutron star. However, this superfluid has been recently found to be entrained by the crust, and as a consequence it does not carry enough angular momentum to explain giant glitches. The extent to which pulsar-timing observations can be reconciled with the standard vortex-mediated glitch theory is studied considering the current uncertainties on dense-matter properties. To this end, the crustal moment of inertia of glitching pulsars is calculated employing a series of different unified dense-matter equations of state.

  11. Preliminary investigation of inertia friction welding B2 aluminides

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Moore, Thomas J.; Kuruzar, Daniel L.

    1987-01-01

    An attempt is made to achieve inertia friction-welding in FeAl and NiAl samples, taking into account their intermetallics' compositions, extrusion parameters, and microstructural data. The energy required for the weld is stored in a rotating flywheel mass attached to one of the two pieces to be joined; when enough energy is introduced, the flywheel is disconnected and an axial load is applied which forces the spinning piece against the stationary one, converting the energy into heat by means of friction. Due to the inherent brittleness of the aluminides, a step-load program was used in which an initial, low-pressure heat buildup increased the work pieces' ductility.

  12. Vibrating Systems with Singular Mass-Inertia Matrices

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1996-01-01

    Vibrating systems with singular mass-inertia matrices arise in recent continuum models of Smart Structures (beams with PZT strips) in assessing the damping attainable with rate feedback. While they do not quite yield 'distributed' controls, we show that they can provide a fixed nonzero lower bound for the damping coefficient at all mode frequencies. The mathematical machinery for modelling the motion involves the theory of Semigroups of Operators. We consider a Timoshenko model for torsion only, a 'smart string,' where the damping coefficient turns out to be a constant at all frequencies. We also observe that the damping increases initially with the feedback gain but decreases to zero eventually as the gain increases without limit.

  13. Parallel algorithms for computation of the manipulator inertia matrix

    NASA Technical Reports Server (NTRS)

    Amin-Javaheri, Masoud; Orin, David E.

    1989-01-01

    The development of an O(log2N) parallel algorithm for the manipulator inertia matrix is presented. It is based on the most efficient serial algorithm which uses the composite rigid body method. Recursive doubling is used to reformulate the linear recurrence equations which are required to compute the diagonal elements of the matrix. It results in O(log2N) levels of computation. Computation of the off-diagonal elements involves N linear recurrences of varying-size and a new method, which avoids redundant computation of position and orientation transforms for the manipulator, is developed. The O(log2N) algorithm is presented in both equation and graphic forms which clearly show the parallelism inherent in the algorithm.

  14. The Inertia Coefficients of an Airship in a Frictionless Fluid

    NASA Technical Reports Server (NTRS)

    Bateman, H.

    1979-01-01

    The apparent inertia of an airship hull is examined. The exact solution of the aerodynamical problem is studied for hulls of various shapes with special attention given to the case of an ellipsoidal hull. So that the results for the ellipsoidal hull may be readily adapted to other cases, they are expressed in terms of the area and perimeter of the largest cross section perpendicular to the direction of motion by means of a formula involving a coefficient kappa which varies only slowly when the shape of the hull is changed, being 0.637 for a circular or elliptic disk, 0.5 for a sphere, and about 0.25 for a spheroid of fineness ratio. The case of rotation of an airship hull is investigated and a coefficient is defined with the same advantages as the corresponding coefficient for rectilinear motion.

  15. The Problem of Inertia in a Friedmann Universe

    NASA Technical Reports Server (NTRS)

    Kazanas, Demosthenes

    2012-01-01

    In this talk I will discuss the origin of inertia in a curved spacetime, particularly the spatially flat, open and closed Friedmann universes. This is done using Sciama's law of inertial induction, which is based on Mach's principle, and expresses the analogy between the retarded far fields of electrodynamics and those of gravitation. After obtaining covariant expressions for electromagnetic fields due to an accelerating point charge in Friedmann models, we adopt Sciama's law to obtain the inertial force on an accelerating mass $m$ by integrating over the contributions from all the matter in the universe. The resulting inertial force has the form $F = -kma$ where the constant $k < 1 $ depends on the choice of the cosmological parameters such as $\\Omega_{M},\\ \\Omega_{\\Lambda}, $ and $\\Omega_{R}$. The values of $k$ obtained suggest that inertial contribution from dark matter can be the source for the missing part of the inertial force.

  16. Dynamic modeling of hydrostatic guideway considering compressibility and inertia effect

    NASA Astrophysics Data System (ADS)

    Du, Yikang; Mao, Kuanmin; Zhu, Yaming; Wang, Fengyun; Mao, Xiaobo; Li, Bin

    2015-03-01

    Hydrostatic guideways are used as an alternative to contact bearings due to high stiffness and high damping in heavy machine tools. To improve the dynamic characteristic of bearing structure, the dynamic modeling of the hydrostatic guidway should be accurately known. This paper presents a "mass-spring-Maxwell" model considering the effects of inertia, squeeze, compressibility and static bearing. To determine the dynamic model coefficients, numerical simulation of different cases between displacement and dynamic force of oil film are performed with fluent code. Simulation results show that hydrostatic guidway can be taken as a linear system when it is subjected to a small oscillation amplitude. Based on a dynamic model and numerical simulation, every dynamic model's parameters are calculated by the Levenberg-Marquardt algorithm. Identification results show that "mass-spring-damper" model is the most appropriate dynamic model of the hydrostatic guidway. This paper provides a reference and preparation for the analysis of the dynamic model of the similar hydrostatic bearings.

  17. Effective Albedo of Vegetated Terrain at L-Band

    NASA Technical Reports Server (NTRS)

    Kurum, Mehmet; O'Neill, Peggy E.; Lang, Roger H.

    2011-01-01

    This paper derives an explicit expression for an effective albedo of vegetated terrain from the zero- and multiple- order radiative transfer (RT) model comparison. The formulation establishes a direct physical link between the effective vegetation parameterization and the theoretical description of absorption and scattering within the canopy. The paper will present an evaluation of the derived albedo for corn canopies with data taken during an experiment at Alabama A&M Winfield A. Thomas Agricultural Research Station near Huntsville, Alabama in June, 1998. The test site consisted of two 50-m x 60-m plots - one with a bare surface and the other with grass cover - and four 30-m x 50-m plots of corn at different planting densities. One corn field was planted at a full density of 9.5 plants/sq m while the others were planted at 1/3, 1/2 and 2/3 of the full density. The fields were observed with a truck-mounted L-band radiometer at incident angle of 15 degree for the period of two weeks. Soil moisture (SM) changed daily due to irrigation and natural rainfall. Variations in gravimetric SM from 18 % to 34 % were seen during this period. Ground truth data, including careful characterization of the corn size and orientation statistics, and its dielectric, was also collected and used to simulate the effective albedo for the vegetation. The single-scattering albedo is defined as the fractional power scattered from individual vegetation constituents with respect to canopy extinction. It represents single-scattering properties of vegetation elements only, and is independent of ground properties. The values of the albedo get higher when there is dense vegetation (i.e. forest, mature corn, etc.) with scatterers, such as branches and trunks (or stalks in the case of corn), which are large with respect to the wavelength. This large albedo leads to a reduction in brightness temperature in the zero-order RT solution (known as tau-omega model). Higher-order multiple-scattering RT

  18. Thermal studies of Martian channels and valleys using Termoskan data

    NASA Astrophysics Data System (ADS)

    Betts, B. H.; Murray, B. C.

    1994-01-01

    The Termoskan instrument on board the Phobos '88 spacecraft acquired the highest spatial resolution thermal infrared emission data ever obtained for Mars. Included in the thermal images 2 km/pixel, midday observations of several major channel and valley systems including significant portions of Shalbatana, Ravi, Al-Qahira, and Ma'adim Valles, the channel connecting Valles Marineris with Hydraotes Chaos, and channel material in Eos Chasma. Termoskan also observed small portions of the southern beginnings of Simud, Tiu, and Ares Valles and some channel material in Gangis Chasma. Simultaneous broadband visible reflectance data were obtained for all but Ma'adim Vallis. We find that most of the channels and valleys have higher thermal inertias than their surroundings, consistent with previous thermal studies. We show for the first time that the thermal inertia boundaries closely match flat channel floor boundaries. Also, buttes within channels have inertias similiar to the plains surrounding the channels, suggesting the buttes are remnants of a contiguous plains surface. Lower bounds on typical channel thermal inertias range from 8.4 to 12.5 (10-3 cal cm-2 s-1/2/K) (352 to 523 in SI units of J m-2 s-1/2/K). Lower bounds on inertia differences with the surrounding heavily cratered plains range from 1.1 to 3.5 (46 to 147 SI). Atmospheric and geometric effects are not sufficient to cause the observed channel inertia enhancements. We favor nonaeolian explanations of the overall channel inertia enhancements based primarily upon the channel floors' thermal homogeneity and the strong correlation of thermal boundaries with floor boundaries. However, localized, dark regions within some channels are likely aeolian in nature as reported previously. Most channels with increased inertias have fretted morphologies such as flat floors with steep walls. Eastern Ravi and southern Ares Valles, the only major channel sections observed that have obvious catastrophic flood bedforms, do not

  19. Influence of polar-cap albedo on past and current Martian climate

    NASA Technical Reports Server (NTRS)

    Kieffer, Hugh H.; Paige, David A.

    1987-01-01

    The finding that the observed albedo of the Martian polar caps increase with increasing isolation is reviewed. Models of the Martian climate system are greatly stabilized when an insolation-dependent frost albedo instead of a constant albedo is used in the energy budget. The authors views on microphysics of the process is then presented. Long term climate models must account for the variability of CO2 frost albedo.

  20. An approximate method for solution to variable moment of inertia problems

    NASA Technical Reports Server (NTRS)

    Beans, E. W.

    1981-01-01

    An approximation method is presented for reducing a nonlinear differential equation (for the 'weather vaning' motion of a wind turbine) to an equivalent constant moment of inertia problem. The integrated average of the moment of inertia is determined. Cycle time was found to be the equivalent cycle time if the rotating speed is 4 times greater than the system's minimum natural frequency.

  1. Thermal Stability of Ice on Ceres with Rough Topography

    NASA Astrophysics Data System (ADS)

    Hayne, Paul O.; Aharonson, Oded

    2015-11-01

    The dwarf planet Ceres may have an ice-rich crust, and subsurface ice exposed by impacts or endogenic activity would be subject to sublimation. The “bright spots” recently discovered by the Dawn mission on the illuminated surface of Ceres have prompted speculation regarding their possible icy composition and the youthful age this might imply. Furthermore, sublimation of ice at the surface or in the interior of Ceres could explain water vapor observed on more than one occasion in the exosphere. We investigated the possible distribution and lifetimes of water ice and other volatiles on Ceres using detailed thermal models, including realistic thermophysical properties and surface roughness.Topographic shadowing creates polar cold traps where a small, but non-negligible fraction (~0.4%) of Ceres' surface is perennially below the ~110 K criterion for 1 Gyr of H2O ice stability. These areas are found above 60° latitude. Other molecules (CH3OH, NH3, SO2, CO2) may be cold-trapped in smaller abundances. A model for the transport, gravitational escape and photoionization of H2O molecules suggests net accumulation in the cold traps. At latitudes 0° - 30°, ice is stable under solar illumination only briefly (~10-100 yr), unless it has high albedo and thermal inertia, in which case lifetimes of > 104 yr are possible.Buried ice is stable within a meter for > 1 Gyr at latitudes higher than ~50°. An illuminated polar cap of water ice would be stable within a few degrees of the poles only if it maintained a high albedo (> 0.5) at present obliquity. If the obliquity exceeded 5° in the geologically recent past, then a putative polar cap would have been erased. Finally, a small hemispheric asymmetry exists due to the timing of Ceres' perihelion passage, which would lead to a detectable enhancement of ice in the northern hemisphere if the orbital elements vary slowly relative to the ice accumulation rate. Our model results are potentially testable during the Dawn science

  2. Report on the ALPO LTP observing program. [for establishing albedo scale for lunar features

    NASA Technical Reports Server (NTRS)

    Cameron, W. S.

    1974-01-01

    Observations of lunar transient phenomena for the Association of Lunar and Planetary Observers (ALPO) are reported. The procedures for making visual observations for estimating albedo are described, and the reported albedo analyzed for lunar topographic features. It is shown that a catalog or scale of albedos can be established for each feature.

  3. The electromagnetic component of albedo from superhigh energy cascades in dense media

    NASA Technical Reports Server (NTRS)

    Golynskaya, R. M.; Hein, L. A.; Plyasheshnikov, A. V.; Vorobyev, K. V.

    1985-01-01

    Albedo from cascades induced in iron by high energy gamma quanta were Monte Carlo simulated. Thereafter the albedo electromagnetic component from proton induced cascades were calculated analytically. The calculations showed that the albedo electromagnetic component increases more rapidly than the nuclear active component and will dominate at sufficiently high energies.

  4. Albedo Response of Native and Artificial Soils to a Wetting Event: Implications for Critical Zone Processes

    NASA Astrophysics Data System (ADS)

    Lovell, L.; Sanchez-Mejia, Z. M.; Papuga, S. A.

    2012-12-01

    The Landscape Evolution Observatory (LEO) at Biosphere 2 is composed of three experimental hill slopes filled to one meter depth of a ground basaltic tephra soil, set up to investigate critical zone processes. Our goal is to understand the energy aspects of this artificial LEO soil; surfaces with a high surface reflectance (albedo) may limit energy available for critical zone processes. The albedo of a surface can change, e.g. by vegetation growth or soil wetting, which can further influence available energy. Here, we examine the soil moisture and albedo response of LEO soil to a 10 mm rainfall event, and compare the results to those found using traditional potting and native desert soils that differ in color and texture. We hypothesized that: 1) increased soil moisture would decrease albedo for all soil types; 2) a smaller wetting front would maximize any decrease in albedo, and 3) albedo will reach a minimum within hours of a rainstorm, returning to a maximum albedo value within the day. We found that albedo was lowest under wet conditions for all soils, regardless of initial color and texture. Additionally, the LEO soil experienced the shallowest wetting front and also showed the most significant decrease in albedo following rainfall. After the rainfall event, all soils showed an initial decrease in albedo, followed by an increase in albedo as the soil dried. While the albedo and soil moisture of each soil reacted similarly, the very dark and fine LEO soil showed the strongest response to wetting.

  5. Effects of fluid inertia and turbulence on force coefficients for squeeze film dampers

    NASA Technical Reports Server (NTRS)

    Andres, L. S.; Vance, J. M.

    1984-01-01

    The effects of fluid inertia and turbulence on the force coefficients of squeeze film dampers are investigated analytically. Both the convective and the temporal terms are included in the analysis of inertia effects. The analysis of turbulence is based on friction coefficients currently found in the literature for Poiseuille flow. The effect of fluid inertia on the magnitude of the radial direct inertia coefficient (i.e., to produce an apparent added mass at small eccentricity ratios, due to the temporal terms) is found to be completely reversed at large eccentricity ratios. The reversal is due entirely to the inclusion of the convective inertia terms in the analysis. Turbulence is found to produce a large effect on the direct damping coefficient at high eccentricity ratios. For the long or sealed squeeze film damper at high eccentricity ratios, the damping prediction with turbulence included is an order of magnitude higher than the laminar solution.

  6. Searching for Thermal Anomalies on Icy Satellites: Step 1- Validation of the Three Dimensional Volatile-Transport (VT3D)

    NASA Astrophysics Data System (ADS)

    Simmons, Gary G.; Howett, Carly J. A.; Young, Leslie A.; Spencer, John R.

    2015-11-01

    In the last few decades, thermal data from the Galileo and Cassini spacecraft have detected various anomalies on Jovian and Saturnian satellites, including the thermally anomalous “PacMan” regions on Mimas and Tethys and the Pwyll anomaly on Europa (Howett et al. 2011, Howett et al. 2012, Spencer et al. 1999). Yet, the peculiarities of some of these anomalies, like the weak detection of the “PacMan” anomalies on Rhea and Dione and the low thermal inertia values of the widespread anomalies on equatorial Europa, are subjects for on-going research (Howett et al. 2014, Rathbun et al. 2010). Further, analysis and review of all the data both Galileo and Cassini took of these worlds will provide information of the thermal inertia and albedos of their surfaces, perhaps highlighting potential targets of interest for future Jovian and Saturnian system missions. Many previous works have used a thermophysical model for airless planets developed by Spencer (1990). However, the Three Dimensional Volatile-Transport (VT3D) model proposed by Young (2012) is able to predict surface temperatures in significantly faster computation time, incorporating seasonal and diurnal insolation variations. This work is the first step in an ongoing investigation, which will use VT3D’s capabilities to reanalyze Galileo and Cassini data. VT3D, which has already been used to analyze volatile transport on Pluto, is validated by comparing its results to that of the Spencer thermal model. We will also present our initial results using VT3D to reanalyze the thermophysical properties of the PacMan anomaly previous discovered on Mimas by Howett et al. (2011), using temperature constraints of diurnal data from Cassini/CIRS. VT3D is expected to be an efficient tool in identifying new thermal anomalies in future Saturnian and Jovian missions.Bibliography:C.J.A. Howett et al. (2011), Icarus 216, 221.C.J.A. Howett et al. (2012), Icarus 221, 1084.C.J.A. Howett et al. (2014), Icarus 241, 239.J

  7. Inertial stochastic dynamics. II. Influence of inertia on slow kinetic processes of supercoiled DNA

    NASA Astrophysics Data System (ADS)

    Beard, Daniel A.; Schlick, Tamar

    2000-05-01

    We apply our new algorithms presented in the companion paper (LTID: long-time-step inertial dynamics, IBD: inertial Brownian dynamics) for mass-dependent Langevin dynamics (LD) with hydrodynamics, as well as the standard Brownian dynamical (BD) propagator, to study the thermal fluctuations of supercoiled DNA minicircles. Our DNA model accounts for twisting, bending, and salt-screened electrostatic interactions. Though inertial relaxation times are on the order of picoseconds, much slower kinetic processes are affected by the Brownian (noninertial) approximation typically employed. By comparing results of LTID and IBD to those generated using the standard (BD) algorithm, we find that the equilibrium fluctuations in writhing number, Wr, and radius of gyration, Rg, are influenced by mass-dependent terms. The autocorrelation functions for these quantities differ between the BD simulations and the inertial LD simulations by as much as 10%. In contrast, when the nonequilibrium process of relaxation from a perturbed state is examined, all methods (inertial and diffusive) yield similar results with no detectable statistical differences between the mean folding pathways. Thus, while the evolution of an ensemble toward equilibrium is equally well described by the inertial and the noninertial methods, thermal fluctuations are influenced by inertia. Examination of such equilibrium fluctuations in a biologically relevant macroscopic property—namely the two-site intermolecular distance—reveals mass-dependent behavior: The rate of juxtaposition of linearly distant sites along a 1500-base pair DNA plasmid, occurring over time scales of milliseconds and longer, is increased by about 8% when results from IBD are compared to those from BD. Since inertial modes that decay on the picosecond time scale in the absence of thermal forces exert an influence on slower fluctuations in macroscopic properties, we advocate that IBD be used for generating long-time trajectories of supercoiled

  8. Comet 67P: Thermal Maps and Local Properties as Derived from Rosetta/VIRTIS data

    NASA Astrophysics Data System (ADS)

    Tosi, Federico; Capria, Maria Teresa; Capaccioni, Fabrizio; Filacchione, Gianrico; Erard, Stéphane; Leyrat, Cédric; Bockelée-Morvan, Dominique; De Sanctis, Maria Cristina; Raponi, Andrea; Ciarniello, Mauro; Schmitt, Bernard; Arnold, Gabriele; Mottola, Stefano; Fonti, Sergio; Palomba, Ernesto; Longobardo, Andrea; Cerroni, Priscilla; Piccioni, Giuseppe; Drossart, Pierre; Kuehrt, Ekkehard

    2015-04-01

    Comet 67P is shown to be everywhere rich in organic materials with little to no water ice visible on the surface. In the range of heliocentric distances from 3.59 to 2.74 AU, daytime observed surface temperatures retrieved from VIRTIS data are overall comprised in the range between 180 and 220 K, which is incompatible with large exposures of water ice and is consistent with a low-albedo, organics-rich surface. The accuracy of temperature retrieval is as good as a few K in regions of the comet unaffected by shadowing or limb proximity. Maximum temperature values as high as 230 K have been recorded in very few places. The highest values of surface temperature in the early Mapping phase were obtained in August 2014, during observations at small phase angles implying that the observed surface has a large predominance of small incidence angles, and local solar times (LST) centered around the maximum daily insolation. In all cases, direct correlation with topographic features is observed, i.e. largest temperature values are generally associated with the smallest values of illumination angles. So far, there is no evidence of thermal anomalies, i.e. places of the surface that are intrinsically warmer or cooler than surrounding terrains observed at the same local solar time and under similar solar illumination. For a given LST, the maximum temperature mainly depends on the solar incidence angle and on surface properties such as thermal inertia and albedo. Since VIRTIS is able to observe the same point of the surface on various occasions under different conditions of solar illumination and LST, it is possible to reconstruct the temperature of that point at different times of the comet's day, thus building diurnal profiles of temperature that are useful to constrain thermal inertia. The availability of spatially-resolved, accurate temperature observations, significantly spaced out in local solar time, provides clues to the physical structure local features, which complements

  9. Long term surface albedo datasets generated with Meteosat images

    NASA Astrophysics Data System (ADS)

    Lattanzio, A.; Govaerts, Y. M.; Theodore, B.

    2009-04-01

    The Global Climate Observing System (GCOS) has recognized the importance and the key-role of the surface albedo in the study of the climate change. This and the other climate variables, called Essential Climate Variables (ECVs), must satisfy the following requirements: (i) a global coverage over long-term periods with adequate spatial and temporal resolution, (ii) reliability and accuracy as well as a (iii) quality control. The Coordination Group for Meteorological Satellites (CGMS) assigned to EUMETSAT an action (T18 (TF7)) in order to prototype and test a new algorithm able to retrieve surface albedo using geostationary satellites as described in the "Implementation plan for the global observing system for climate in support of the UNFCCC" document (WMO/TD No. 1219). In this frame EUMETSAT decided to develop a new specific algorithm, named Meteosat Surface Albedo (MSA), based on a method proposed by Pinty et al. The MSA algorithm is currently running in the operational reprocessing facility of EUMETSAT in order to generate reliable albedo data set starting from 1982. These data have been acquired by six different radiometers. As Meteosat first generation satellites have not been designed for climate monitoring, before proceeding with the interpretation of the complete archive (~ 25 years of data), a detailed temporal consistency analysis of the albedo data set generated with the MSA algorithm has been performed in order to check the compliance with points (ii) and (iii). Specific efforts have been put on the estimation of the measurement error accounting for the observation uncertainties and retrieval method assumptions. Currently 100% of the archive for the prime mission at 0 degree has been processed and the albedo data set can be requested from the EUMETSAT archive facility. This paper will present the method elaborated for the evaluation of the temporal consistency of the MSA data set and illustrate typical problems raising from the processing of old data and

  10. Dynamic Albedo of Neutrons (DAN) Experiment Onboard NASA's Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Mitrofanov, I. G.; Litvak, M. L.; Varenikov, A. B.; Barmakov, Y. N.; Behar, A.; Bobrovnitsky, Y. I.; Bogolubov, E. P.; Boynton, W. V.; Harshman, K.; Kan, E.; Kozyrev, A. S.; Kuzmin, R. O.; Malakhov, A. V.; Mokrousov, M. I.; Ponomareva, S. N.; Ryzhkov, V. I.; Sanin, A. B.; Smirnov, G. A.; Shvetsov, V. N.; Timoshenko, G. N.; Tomilina, T. M.; Tret'yakov, V. I.; Vostrukhin, A. A.

    2012-09-01

    The description of Dynamic Albedo of Neutrons (DAN) experiment is presented, as a part of the NASA's Mars Science Laboratory mission onboard the mars rover Curiosity. The instrument DAN includes Pulsing Neutron Generator (PNG) producing pulses of 14.1 MeV neutrons for irradiation of subsurface material below the rover, and Detectors and Electronics (DE) unit, which operates the instrument itself and measures the die-away time profiles of epithermal and thermal neutrons following each neutron pulse. It is shown that the DAN investigation will measure a content of hydrogen along the path of the MSL rover, and it will also provide information about a depth distribution of hydrogen at 10-20 regions selected for the detailed studies and sampling analysis.

  11. AVHRR Surface Temperature and Narrow-Band Albedo Comparison with Ground Measurements for the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Haefliger, M.; Steffen, K.; Fowler, C.

    1993-01-01

    An ice-surface temperature retrieval algorithm for the Greenland ice sheet was developed using NOAA 11 thermal radiances from channels 4 and 5. Temperature, pressure and humidity profiles, cloud observations and skin temperatures from the Swiss Federal Institute of Technology (ETH) camp, located at the equilibrium line altitude at 49 deg17 min W, 69 deg 34 min N, were used in the LOWTRAN 7 model. Through a statistical analysis of daily clear sky profiles, the coefficients that correct for the atmospheric effects were determined for the ETH-Camp field season (May to August). Surface temperatures retrieved by this method were then compared against the in situ observations with a maximum difference of 0.6 K. The NOAA 11 narrow-band planetary albedo values for channels 1 and 2 were calculated using pre-launch calibration coefficients. Scattering and absorption by the atmosphere were modelled with LOWTRAN 7. Then, narrow-band albedo values for the AVHRR visible and near infrared channels were compared with in situ high resolution spectral reflectance measurements. In the visible band (580-680 nm), AVHRR-derived narrow-band albedo and the in situ measurements corrected with radiative transfer model LOWTRAN 7 showed a difference of less than 2%. For the near infrared channel (725-1100 nm) the difference between the measured and modelled narrow-band albedo was 14%. These discrepancies could be either the result of inaccurate aerosol scattering modelling (lack of the in situ observation), or the result of sensor drift due to degradation.

  12. Cassini Imaging of Iapetus and Solution of the Albedo Asymmetry Enigma

    NASA Astrophysics Data System (ADS)

    Denk, Tilmann; Spencer, John

    2014-05-01

    Cassini imaging of Iapetus during one close and several more distant flybys mainly in the first years of the mission revealed an alien and often unique landscape of this third-largest moon in the Saturnian system [1]. The data show numerous impact craters on the bright and dark terrain, equator-facing dark and pole-facing bright crater walls, huge impact basins, rather minor endogenic geologic features, a non-spherical, but ellipsoidal shape, a giant ridge which spans across half of Iapetus' circumference exactly along the equator, a newly detected global 'color dichotomy' presumably formed by dust from retrograde irregular moons, and of course the famous extreme global albedo asymmetry which has been an enigma for more than three centuries. Revealing the cause of this 'albedo dichotomy' enigma of Iapetus, where the trailing side and poles are more than 10x brighter than the leading side, was one of the major tasks for the Cassini mission. It has now been solved successfully. In the mid-1970es, deposition of exogenic dark material on the leading side, originating from outer retrograde moon Phoebe, was proposed as the cause. But this alone could not explain the global shape, sharpness, and complexity of the transition between Iapetus' bright and dark terrain. Mainly with Cassini spectrometer (CIRS) and imaging (ISS) data, all these characteristics and the asymmetry's large amplitude are now plausibly explained by runaway global thermal migration of water ice, triggered by the deposition of dark material on the leading hemisphere. This mechanism is unique to Iapetus among the Saturnian satellites for many reasons. Most important are Iapetus' slow rotation which produces unusually high daytime temperatures and water ice sublimation rates, and the size (gravity) of Iapetus which is small enough for global migration of water ice but large enough that much of the ice is retained on the surface [2]. References: [1] Denk, T., Neukum, G., Roatsch, Th., Porco, C.C., Burns, J

  13. Albedo of coastal landfast sea ice in Prydz Bay, Antarctica: Observations and parameterization

    NASA Astrophysics Data System (ADS)

    Yang, Qinghua; Liu, Jiping; Leppäranta, Matti; Sun, Qizhen; Li, Rongbin; Zhang, Lin; Jung, Thomas; Lei, Ruibo; Zhang, Zhanhai; Li, Ming; Zhao, Jiechen; Cheng, Jingjing

    2016-05-01

    The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica (off Zhongshan Station) during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters (e.g., snow thickness, ice thickness, surface temperature, and air temperature) were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed, which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.

  14. Comparison of spectral surface albedos and their impact on the general circulation model simulated surface climate

    NASA Astrophysics Data System (ADS)

    Roesch, A.; Wild, M.; Pinker, R.; Ohmura, A.

    2002-07-01

    This study investigates the impact of spectrally resolved surface albedo on the total surface albedo. The neglect of albedo variation within the shortwave spectrum may lead to substantial errors as the atmospheric water greatly influences the spectral distribution of the incoming radiation. It is shown that ignoring the spectral dependence of the surface albedo will affect the predicted climate. The study reveals substantial changes in the climate over northern Africa when modifying the surface albedo of the Sahara deserts. Detailed information is given how the European Center/Hamburg General Circulation Model (ECHAM4) can be extended to include surface boundary conditions for both the visible and near-infrared incoming radiation. This comprises global climatologies for both the visible and near-infrared albedo for snow-free conditions, as well as the corresponding albedo values over snow, land-/sea ice and over snow covered forests. Comparisons between several available surface albedo climatologies and a newly compiled albedo data set show substantial scatter in estimated albedos. The largest albedo differences are found in snow covered forest regions as well as in arid and semi-arid terrains.

  15. Evaluating biases in simulated land surface albedo from CMIP5 global climate models

    NASA Astrophysics Data System (ADS)

    Li, Yue; Wang, Tao; Zeng, Zhenzhong; Peng, Shushi; Lian, Xu; Piao, Shilong

    2016-06-01

    Land surface albedo is a key parameter affecting energy balance and near-surface climate. In this study, we used satellite data to evaluate simulated surface albedo in 37 models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5). There was a systematic overestimation in the simulated seasonal cycle of albedo with the highest bias occurring during the Northern Hemisphere's winter months. The bias in surface albedo during the snow-covered season was classified into that in snow cover fraction (SCF) and albedo contrast (β1). There was a general overestimation of β1 due to the simulated snow-covered albedo being brighter than the observed value; negative biases in SCF were not always related to negative albedo biases, highlighting the need for realistic representation of snow-covered albedo in models. In addition, models with a lower leaf area index (LAI) tend to produce a higher surface albedo over the boreal forests during the winter, which emphasizes the necessity of improving LAI simulations in CMIP5 models. Insolation weighting showed that spring albedo biases were of greater importance for climate. The removal of albedo biases is expected to improve temperature simulations particularly over high-elevation regions.

  16. MISR Level 2 TOA/Cloud Albedo parameters (MIL2TCAL_V2)

    NASA Technical Reports Server (NTRS)

    Diner, David J. (Principal Investigator)

    The TOA/Cloud Albedo data contain albedo values, including finely-sampled or local (2.2 km) TOA albedos registered to the RLRA, and two coarsely-sampled (35.2 km resolution) TOA albedos projected to 30-km altitude. The local (2.2 km) albedos do not take the obscuration of cloud features into account, so they should only be treated as traditional albedos when the number of obscured pixels is low. The restrictive and expansive albedos are both available at 35.2 km resolution: the restrictive albedos are only calculated using the radiation upwelling from the pixel under consideration, whereas the expansive albedos use all the radiation emanating from the surrounding area. Therefore, the expansive albedo is closer to the traditional definition of top-of-atmosphere albedos. [Temporal_Coverage: Start_Date=2000-02-24; Stop_Date=] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1.1 km; Longitude_Resolution=1.1 km; Temporal_Resolution=about 15 orbits/day].

  17. Durability of high-albedo roof coatings and implications for cooling energy savings. Final report

    SciTech Connect

    Bretz, S.E.; Akbari, H.

    1994-06-01

    Twenty-six spot albedo measurements of roofs were made using a calibrated pyranometer. The roofs were surfaced with either an acrylic elastomeric coating, a polymer coating with an acrylic base, or a cementitious coating. Some of the roofs` albedos were measured before and after washing to determine whether the albedo decrease was permanent. Data indicated that most of the albedo degradation occurred within the first year, and even within the first two months. On one roof, 70% of one year`s albedo degradation occurred in the first two months. After the first year, the degradation slowed, with data indicating small losses in albedo after the second year. Measurements of seasonal cooling energy savings by Akbari et al. (1993) included the effects of over two months of albedo degradation. We estimated {approximately}20% loss in cooling-energy savings after the first year because of dirt accumulation. For most of the roofs we cleaned, the albedo was restored to within 90% of its initial value. Although washing is effective at restoring albedo, the increase in energy savings is temporary and labor costs are significant in comparison to savings. By our calculations, it is not cost-effective to hire someone to clean a high-albedo roof only to achieve energy savings. Thus, it would be useful to develop and identify dirt-resistant high-albedo coatings.

  18. Emotional Inertia is Associated with Lower Well-Being when Controlling for Differences in Emotional Context

    PubMed Central

    Koval, Peter; Sütterlin, Stefan; Kuppens, Peter

    2016-01-01

    Previous studies have linked higher emotional inertia (i.e., a stronger autoregressive slope of emotions) with lower well-being. We aimed to replicate these findings, while extending upon previous research by addressing a number of unresolved issues and controlling for potential confounds. Specifically, we report results from two studies (Ns = 100 and 202) examining how emotional inertia, assessed in response to a standardized sequence of emotional stimuli in the lab, correlates with several measures of well-being. The current studies build on previous research by examining how inertia of both positive emotions (PE) and negative emotions (NE) relates to positive (e.g., life satisfaction) and negative (e.g., depressive symptoms) indicators of well-being, while controlling for between-person differences in the mean level and variability of emotions. Our findings replicated previous research and further revealed that (a) NE inertia was more strongly associated with lower well-being than PE inertia; (b) emotional inertia correlated more consistently with negative indicators (e.g., depressive symptoms) than positive indicators (e.g., life satisfaction) of well-being; and (c) these relationships were independent of individual differences in mean level and variability of emotions. We conclude, in line with recent findings, that higher emotional inertia, particularly of NE, may be an indicator of increased vulnerability to depression. PMID:26779099

  19. Preliminary albedo map of the south polar region

    NASA Technical Reports Server (NTRS)

    Devaucouleurs, G.; Roth, J.; Mulholand, C.

    1973-01-01

    A preliminary albedo map of the Martian south polar region in stereographic projection was prepared mainly from mission test video system (MTVS) prints before rectified and gridded prints were received, but some adjustments were made to conform with a semi-controlled photomosaic. Wherever possible, use also was made of crater coordinates. Two versions of the map are presented: one with a coordinate grid overlay and one without it. The precision of the coordinates is generally within 1 deg in latitude and the corresponding are in longitude. The maps show both the albedo markings and, with subdued contrast, the craters and topographic features that are necessary to locate the former. The map covers the range of latitudes from - 65 deg to the south pole.

  20. Comparison of MISR and MODIS land surface albedos: Methodology

    NASA Astrophysics Data System (ADS)

    Taberner, M.; Pinty, B.; Govaerts, Y.; Liang, S.; Verstraete, M. M.; Gobron, N.; Widlowski, J.-L.

    2010-03-01

    The broadband white sky surface albedo (bihemispherical reflectance) products available from the Moderate Resolution Imaging Spectroradiometer (MODIS) are compared at regional and continental scales with similar products generated from the Multiangle Imaging Spectroradiometer (MISR) land surface bidirectional reflectance factor (BRF) parameters. This paper describes the methodology applied to derive MISR white sky albedos over four spectral broadbands of interest, namely, 0.3-0.7 μm, 0.4-1.1 μm, 0.7-3.0 μm, and 0.3-3.0 μm, as well as an evaluation of the strategy adopted to compare the MODIS and MISR products. The results are very encouraging since the two data sets show very good statistical agreement over large areas and over a full year of measurements, despite the many differences that exist in the suite of algorithms applied to retrieve these surface quantities from each of these instruments separately.

  1. Exogenic and endogenic albedo and color patterns on Europa

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.

    1986-01-01

    New global and high-resolution multispectral mosaics of Europa have been produced from the Voyager imaging data. Photometric normalizations are based on multiple-image techniques that explicitly account for intrinsic albedo variations through pixel-by-pixel solutions. The exogenic color and albedo pattern on Europa is described by a second-order function of the cosine of the angular distance from the apex of orbital motion. On the basis of this second-order function and of color trends that are different on the leading and trailing hemispheres, the exogenic pattern is interpreted as being due to equilibrium between two dominant processes: (1) impact gardening and (2) magnetospheric interactions, including sulfur-ion implantation and sputtering redistribution. Removal of the model exogenic pattern in the mosaics reveals the endogenic variations, consisting of only two major units: darker (redder) and bright materials. Therefore Europa's visual spectral reflectivity is simple, having one continuous exogenic pattern and two discrete endogenic units.

  2. Deriving Albedo from Coupled MERIS and MODIS Surface Products

    NASA Technical Reports Server (NTRS)

    Gao, Feng; Schaaf, Crystal; Jin, Yu-Fang; Lucht, Wolfgang; Strahler, Alan

    2004-01-01

    MERIS Level 2 surface reflectance products are now available to the scientific community. This paper demonstrates the production of MERIS-derived surface albedo and Nadir Bidirectional Reflectance Distribution Function (BRDF) adjusted reflectances by coupling the MERIS data with MODIS BRDF products. Initial efforts rely on the specification of surface anisotropy as provided by the global MODIS BRDF product for a first guess of the shape of the BRDF and then make use all of the coincidently available, partially atmospherically corrected, cloud cleared, MERIS observations to generate MERIS-derived BRDF and surface albedo quantities for each location. Comparisons between MODIS (aerosol-corrected) and MERIS (not-yet aerosol-corrected) surface values from April and May 2003 are also presented for case studies in Spain and California as well as preliminary comparisons with field data from the Devil's Rock Surfrad/BSRN site.

  3. Land Surface Albedo from MERIS Reflectances Using MODIS Directional Factors

    NASA Technical Reports Server (NTRS)

    Schaaf, Crystal L. B.; Gao, Feng; Strahler, Alan H.

    2004-01-01

    MERIS Level 2 surface reflectance products are now available to the scientific community. This paper demonstrates the production of MERIS-derived surface albedo and Nadir Bidirectional Reflectance Distribution Function (BRDF) adjusted reflectances by coupling the MERIS data with MODIS BRDF products. Initial efforts rely on the specification of surface anisotropy as provided by the global MODIS BRDF product for a first guess of the shape of the BRDF and then make use all of the coincidently available, partially atmospherically corrected, cloud cleared, MERIS observations to generate MERIS-derived BRDF and surface albedo quantities for each location. Comparisons between MODIS (aerosol-corrected) and MERIS (not-yet aerosol-corrected) surface values from April and May 2003 are also presented for case studies in Spain and California as well as preliminary comparisons with field data from the Devil's Rock Surfrad/BSRN site.

  4. Temporal Variations in the Uranian Near-IR Geometric Albedo

    NASA Astrophysics Data System (ADS)

    Walter, C. M.; Marley, M. S.; Baines, K. H.

    1996-09-01

    Over the period August 1995 -- August 1996 the near-infrared geometric albedo of Uranus showed distinct variation. We obtained images of the planet in 10 broad and narrowband filters using the ARC 3.5 meter telescope at Apache Point Observatory. Along with the albedo variations we saw significant changes in the contrast of the planet. Data acquired in August 1995 (Walter & Marley 1995) show the same high altitude hazes encircling the south polar region as seen by Baines et al. (1995) from the IRTF two days prior to our observations and by HST in August 1994. Followup images from June 1996 no longer contain this asymmetry, instead showing a homogeneous disk with corresponding lower albedos at matching wavelengths. Observations will also be made in late August 1996. We modeled this data by computing theoretical monochromatic albedos which were then integrated over the filter bandpasses. These filters were chosen to best probe a variety of atmospheric levels, with continuum filters probing down to the CH_4 tropospheric cloud and beyond. Filters selected in the deep H_2 and CH_4 absorption bands allow us to examine the structure of hazes in the upper stratosphere, whose small reflection contributions dominate in these dark filters. Preliminary analysis of information from two very different states of Uranian weather shows evidence for temporal variability in the vertical location and thickness of the CH_4 cloud as well as the incompatibility of extrapolating optical stratospheric haze characteristics in the near-infrared. This work was supported by NASA grant NGT-51383. Baines, K. H., Yanamandra-Fisher, P., Lebofsky, L. A., Momary, T. W., & Golisch, W. 1995, BAAS, 27, 1088. Walter, C & Marley, M. S. 1995, BAAS, 27, 1089.

  5. A wide angle earth albedo sensor for spacecraft attitude determinations

    NASA Astrophysics Data System (ADS)

    Cruise, A. M.; Barnsdale, K.; Bowles, J. A.; Coker, A. J.; Sheather, P. H.

    1991-03-01

    A design is proposed for an earth albedo sensor which meets the conflicting parameters of a wide field of view and high sensitivity by using large area photodiodes and a very low noise dc amplifier. Two units have been launched on the United Kingdom Satellite of the Active Magnetospheric Particle tracer Experiment mission and operated successfully, measuring spacecraft attitude to an accuracy of one degree.

  6. Extended HXR Sources - Albedo Patches or Coronal Sources

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.

    2011-01-01

    Extended HXR sources in the presence of compact footpoints have been reported based on visibility amplitudes from different detectors. Attempts have been made to determine the location and extent of these sources through direct imaging. Results of this work will be described for simulated sources and for specific flares at different solar longitudes, with a discussion of the possible nature of the extended sources as either albedo patches or coronal sources or a combination of the two.

  7. An Improved Degree-day Melt Model Considering Albedo

    NASA Astrophysics Data System (ADS)

    Pellicciotti, F.; Strasser, U.; Burlando, P.; Funk, M.; Brock, B.; Corripio, J.

    Albedo is a major controlling factor for the melting of snow and ice. Here, an en- hanced degree-day melt model for the point scale is presented, in which the classical dependency on temperature is extended by considering albedo and global radiation. Temperature based index melt methods have been widely used due to their good per- formances, the availability of temperature data and the ease of its spatial interpolation. Other authors have recently improved the standard approach by addition of a radiation term. Here, the latter is modified with albedo, which represents a physical property of the material, and accounts for the way the surface reacts to the energy input of global radiation. The formulation adopted is additive, being melt expressed as the sum of two components, one controlled by temperature and the second by short-wave incoming radiation. Such a representation allows to separate in a clear way the two important contributions to melt of long wave and global radiation The model was run at different sites where the necessary meteorological data are measured and melt values are avail- able. In the pre-alpine site of Col de Porte (French Alps, 1340m), melt was computed by use of a highly sophisticated, physically based energy balance model. An ultrasonic device was used at a glacier location on Haut Glacier d'Arolla (Swiss Alps, 2920 m). Both measured short-wave radiation and computed potential direct short-wave radia- tion were used, and different temporal resolutions were tested. Results are discussed with the purpose of evaluating the increased efficiency of the improved degree-day scheme, and in the light of extending it to a distributed model, which accounts for space-time albedo variability.

  8. Signatures of volatiles in the lunar proton albedo

    NASA Astrophysics Data System (ADS)

    Schwadron, N. A.; Wilson, J. K.; Looper, M. D.; Jordan, A. P.; Spence, H. E.; Blake, J. B.; Case, A. W.; Iwata, Y.; Kasper, J. C.; Farrell, W. M.; Lawrence, D. J.; Livadiotis, G.; Mazur, J.; Petro, N.; Pieters, C.; Robinson, M. S.; Smith, S.; Townsend, L. W.; Zeitlin, C.

    2016-07-01

    We find evidence for hydrated material in the lunar regolith using "albedo protons" measured with the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO). Fluxes of these albedo protons, which are emitted from the regolith due to steady bombardment by high energy radiation (Galactic Cosmic Rays), are observed to peak near the poles, and are inconsistent with the latitude trends of heavy element enrichment (e.g., enhanced Fe abundance). The latitudinal distribution of albedo protons anti-correlates with that of epithermal or high energy neutrons. The high latitude enhancement may be due to the conversion of upward directed secondary neutrons from the lunar regolith into tertiary protons due to neutron-proton collisions in hydrated regolith that is more prevalent near the poles. The CRaTER instrument may thus provide important measurements of volatile distributions within regolith at the Moon and potentially, with similar sensors and observations, at other bodies within the Solar System.

  9. Albedo feedback enhanced by smoother Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Landy, Jack C.; Ehn, Jens K.; Barber, David G.

    2015-12-01

    The ICESat operational period 2003-2008 coincided with a dramatic decline in Arctic sea ice—linked to prolonged melt season duration and enhanced melt pond coverage. Although melt ponds evolve in stages, sea ice with smoother surface topography typically allows the pond water to spread over a wider area, reducing the ice-albedo and accelerating further melt. Here we develop this theory into a quantitative relationship between premelt sea ice surface roughness and summer melt pond coverage. Our method, applied to ICESat observations of the end-of-winter sea ice roughness, can account for 85% of the variance in advanced very high resolution radiometer (AVHRR) observations of the summer ice-albedo. An Arctic-wide reduction in sea ice roughness from 2003 to 2008 explains a drop in ice-albedo that resulted in a 16% increase in solar heat input to the sea ice cover, which represents ten times the heat input contributed by earlier melt onset timing over the same period.

  10. Gamma-ray Albedo of Small Solar System Bodies

    SciTech Connect

    Moskalenko, I.V.

    2008-03-25

    We calculate the {gamma}-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the {gamma}-ray albedo for the Main Belt and KBOs strongly depends on the small-body mass spectrum of each system and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). If detected, it can be used to derive the mass spectrum of small bodies in the Main Belt and Kuiper Belt and to probe the spectrum of CR nuclei at close-to-interstellar conditions. The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. Therefore, the {gamma}-ray emission by the Main Belt and Kuiper Belt has to be taken into account when analyzing weak {gamma}-ray sources close to the ecliptic. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center. For details of our calculations and references see [1].

  11. Leading/Trailing Albedo Asymmetries of Thebe, Amalthea, and Metis

    NASA Astrophysics Data System (ADS)

    Simonelli, Damon P.; Rossier, Laura; Thomas, Peter C.; Veverka, Joseph; Burns, Joseph A.; Belton, Michael J. S.

    2000-10-01

    Using Galileo clear-filter images (effective wavelength ≈0.64 μm), we have created the first albedo maps of the small inner jovian satellites Thebe, Amalthea, and Metis. These maps clearly show that the leading sides of all three satellites are significantly brighter than their corresponding trailing sides, confirming and extending a result first reported by P. C. Thomas et al. (1998, Icarus135, 360-371). In particular, on all three moons the leading side is brighter than the trailing side by 25 to 30%. The fact that the direction and size of this albedo asymmetry is identical from satellite to satellite suggests that one common physical mechanism is governing the global albedo patterns of all three moons. The most plausible such mechanism is the impact of macroscopic meteoroids that originated outside the jovian system. These impacts, which eject the dust that forms Jupiter's ring system (M. E. Ockert-Bell et al., 1999, Icarus138, 188-213; J. A. Burns et al., 1999, Science284, 1146-1150), are probably also responsible for brightening the leading sides of these small satellites.

  12. Supercritical Salt Spray for the Implementation of Cloud Albedo Modification

    NASA Astrophysics Data System (ADS)

    Neukermans, A. P.; Cooper, G.; Foster, J. D.; Galbraith, L.; Ormond, B.; Wang, Q.; Johnston, D.; Cloud Brightening Research

    2011-12-01

    Of all the geo-engineering schemes proposed so far, the Latham-Salter cloud albedo modification scheme is perhaps the most benign and "natural" method. In its full deployment, it proposes to densify and thereby modify the albedo of low-hanging marine boundary clouds by a few percent such that the overall earth albedo might be changed by 1%. The scheme would require the production of vast numbers of salt cloud condensation nuclei (CCN), in one implementation on the order of 10^17 per second from each of some 1500 autonomous sailing vessels. We have investigated a number of possible techniques to create these nuclei. We reported previously the laboratory production of suitable nuclei from saltwater using Taylor cones. This method would require about 10^8 Taylor cones per vessel to get to the required CCN production rate, and hence needs a very extensive scale-up effort. We report here on the use of saltwater sprayed at or near its critical temperature and pressure through small nozzles. Although a number of technical problems remain, results to date suggest that this method might be suitable, at least for research purposes. The mean particle size distributions of nuclei generated (40-100 nm) are acceptable, and the scale-up effort to the estimated number of nozzles required (1000-2000) seems reasonable.

  13. Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles.

    PubMed

    Bhattacharjee, Satadeep; Nordström, Lars; Fransson, Jonas

    2012-02-01

    We consider spin dynamics for implementation in an atomistic framework and we address the feasibility of capturing processes in the femtosecond regime by inclusion of moment of inertia. In the spirit of an s-d-like interaction between the magnetization and electron spin, we derive a generalized equation of motion for the magnetization dynamics in the semiclassical limit, which is nonlocal in both space and time. Using this result we retain a generalized Landau-Lifshitz-Gilbert equation, also including the moment of inertia, and demonstrate how the exchange interaction, damping, and moment of inertia, all can be calculated from first principles. PMID:22400957

  14. Surface corrections to the moment of inertia and shell structure in finite Fermi systems

    NASA Astrophysics Data System (ADS)

    Gorpinchenko, D. V.; Magner, A. G.; Bartel, J.; Blocki, J. P.

    2016-02-01

    The moment of inertia for nuclear collective rotations is derived within a semiclassical approach based on the Inglis cranking and Strutinsky shell-correction methods, improved by surface corrections within the nonperturbative periodic-orbit theory. For adiabatic (statistical-equilibrium) rotations it was approximated by the generalized rigid-body moment of inertia accounting for the shell corrections of the particle density. An improved phase-space trace formula allows to express the shell components of the moment of inertia more accurately in terms of the free-energy shell correction. Evaluating their ratio within the extended Thomas-Fermi effective-surface approximation, one finds good agreement with the quantum calculations.

  15. The calculation of the mass moment of inertia of a fluid in a rotating rectangular tank

    NASA Technical Reports Server (NTRS)

    1977-01-01

    This analysis calculated the mass moment of inertia of a nonviscous fluid in a slowly rotating rectangular tank. Given the dimensions of the tank in the x, y, and z coordinates, the axis of rotation, the percentage of the tank occupied by the fluid, and angle of rotation, an algorithm was written that could calculate the mass moment of inertia of the fluid. While not included in this paper, the change in the mass moment of inertia of the fluid could then be used to calculate the force exerted by the fluid on the container wall.

  16. A class of parallel algorithms for computation of the manipulator inertia matrix

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Bejczy, Antal K.

    1989-01-01

    Parallel and parallel/pipeline algorithms for computation of the manipulator inertia matrix are presented. An algorithm based on composite rigid-body spatial inertia method, which provides better features for parallelization, is used for the computation of the inertia matrix. Two parallel algorithms are developed which achieve the time lower bound in computation. Also described is the mapping of these algorithms with topological variation on a two-dimensional processor array, with nearest-neighbor connection, and with cardinality variation on a linear processor array. An efficient parallel/pipeline algorithm for the linear array was also developed, but at significantly higher efficiency.

  17. Moments of Inertia - Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID)

    NASA Technical Reports Server (NTRS)

    Haro, Helida C.

    2010-01-01

    The objective of this research effort is to determine the most appropriate, cost efficient, and effective method to utilize for finding moments of inertia for the Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID). A moment is a measure of the body's tendency to turn about its center of gravity (CG) and inertia is the resistance of a body to changes in its momentum. Therefore, the moment of inertia (MOI) is a body's resistance to change in rotation about its CG. The inertial characteristics of an UAV have direct consequences on aerodynamics, propulsion, structures, and control. Therefore, it is imperative to determine the precise inertial characteristics of the DROID.

  18. Moments of Inertia: Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID)

    NASA Technical Reports Server (NTRS)

    Haro, Helida C.

    2010-01-01

    The objective of this research effort is to determine the most appropriate, cost efficient, and effective method to utilize for finding moments of inertia for the Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID). A moment is a measure of the body's tendency to turn about its center of gravity (CG) and inertia is the resistance of a body to changes in its momentum. Therefore, the moment of inertia (MOI) is a body's resistance to change in rotation about its CG. The inertial characteristics of an UAV have direct consequences on aerodynamics, propulsion, structures, and control. Therefore, it is imperative to determine the precise inertial characteristics of the DROID.

  19. A Change of Inertia-Supporting the Thrust Vector Control of the Space Launch System

    NASA Technical Reports Server (NTRS)

    Dziubanek, Adam J.

    2012-01-01

    The Space Launch System (SLS) is America's next launch vehicle. To utilize the vehicle more economically, heritage hardware from the Space Transportation System (STS) will be used when possible. The Solid Rocket Booster (SRB) actuators could possibly be used in the core stage of the SLS. The dynamic characteristics of the SRB actuator will need to be tested on an Inertia Load Stand (ILS) that has been converted to Space Shuttle Main Engine (SSME). The inertia on the pendulum of the ILS will need to be changed to match the SSME inertia. In this testing environment an SRB actuator can be tested with the equivalent resistence of an SSME.

  20. Graphical analysis of electron inertia induced acoustic instability

    NASA Astrophysics Data System (ADS)

    Karmakar, P. K.; Deka, U.; Dwivedi, C. B.

    2005-03-01

    Recently, the practical significance of the asymptotic limit of me/mi→0 for electron density distribution has been judged in a two-component plasma system with drifting ions. It is reported that in the presence of drifting ions with drift speed exceeding the ion acoustic wave speed, the electron inertial delay effect facilitates the resonance coupling of the usual fluid ion acoustic mode with the ion-beam mode. In this contribution the same instability is analyzed by graphical and numerical methods. This is to note that the obtained dispersion relation differs from those of the other known normal modes of low frequency ion plasma oscillations and waves. This is due to consideration of electron inertial delay in derivation of the dispersion relation of the ion acoustic wave fluctuations. Numerical calculations of the dispersion relation and wave energy are carried out to depict the graphical appearance of poles and positive-negative enegy modes. It is found that the electron inertia induced ion acoustic wave instability arises out of linear resonance coupling between the negative and positive energy modes. Characterization of the resonance nature of the instability in Mach number space for different wave numbers of the ion acoustic mode is presented.