Search

The stability of the residual carbon dioxide cap near the south pole of Mars is currently not well understood. The cap's survival depends on its radiation budget, controlled by the visible albedo and infrared emissivity. We investigated the role of CO2 snowfall in altering the albedo and emissivity, leading to the observed asymmetry in the net CO2 accumulation at the two poles. Uncontaminated snowfall increases albedo, and lowers emissivity, due to scattering by optically thick clouds and granular surface deposits. Data from the Mars Climate Sounder (MCS) show that fall and winter snowfall is correlated with higher springtime albedo at both poles. For the seasonal CO2 deposits in each polar region >60° latitude, we find mean albedo values of 0.39 in the north and 0.51 in the south, and winter 32‐μm emissivity values of 0.84 in the north and 0.87 in the south. Using a radiative transfer model and the MCS data, we find that the north polar deposits have ∼10× higher dust content than those in the south, explaining the ∼31% lower albedo of the north seasonal cap during spring. Our model shows that greater amounts of snowfall can explain the ∼4% lower emissivity of the north polar seasonal cap. These findings demonstrate that winter snowfall and dust transport affect the composition of Mars' seasonal ice caps and polar energy balance. Snowfall and dust loading are therefore important in modeling the CO2 cycle on Mars, as well as the planet's long‐term climate variations. Plain Language Summary: The permanent carbon dioxide (CO2, also known as dry ice) deposits on Mars control the planet's global atmospheric pressure. Seasonal fluctuations of the CO2 cycle drive pressure variations measured at the surface anywhere on the planet. These variations are buffered by the stable permanent CO2 deposit at the south pole. The north pole has the more favorable altitude and pressure to be in equilibrium with the atmosphere, but satellite observations showed that the residual cap at the south pole was in equilibrium and not the north. Other studies found evidence of carbon dioxide snowfall in both polar regions. Using data from Mars Climate Sounder on board the Mars Reconnaissance Orbiter, we found that there is an asymmetry between the optical properties of the northern and the southern permanent caps. We attribute this asymmetry to dust and snowfall quantities, which promote more CO2 accumulation in the south, relative to the north. Key Points: Infrared emissivity and visible albedo of Mars' seasonal ice caps are correlatedThe north seasonal cap has greater snowfall, lower emissivity, and lower albedoHigher dust loading in the northern fall and winter seasons causes lower ice cap albedo [ABSTRACT FROM AUTHOR]

In this study a polydyne cam and a roller follower with different cam rotational speeds are analyzed. The chaos has been investigated based on positive Lyapunov exponent value. The effect of follower guide’s clearance on chaos is considered. The contact between cam and follower is simulated by using Solidworks program. The power spectrum of Fast Fourier Transform and phase plane have been examined the follower non-periodicity during follower motion in the y-direction. Rosenstein program is used to calculate largest Lyapunov exponent. The experimental setup has been implemented by using OPTOTRAK/3020 through a 3-D infrared markers to track follower motion. The signal of follower motion in the y-direction has been processed depend upon data acquisition technique. The system with follower guide’s clearance C = 2 mm is more chaotic than the others at cam rotational speed N = 800 rpm and N = 1200 rpm. The simulation and experimental results are compared and verified for largest Lyapunov exponent. [ABSTRACT FROM AUTHOR]

Based on the archival images of the Hubble Space Telescope we performed stellar photometry in the infrared and visible ranges in the fields of the Maffei 1, Maffei 2 and IC 342 galaxies, the light from which undergoes strong absorption by the interstellar gas and dust clouds of our Galaxy. The resulting Hertzsprung-Russell diagrams reveal red giant branches and the positions of their upper boundaries and color indices. A comparison of color indices of the red giant branch with similar indices in the galaxies not experiencing extinction made it possible to determine the amount of extinction in Maffei 1, Maffei 2 and IC 342 as follows: AV = 3.06, 3.65 and 0.95, respectively. We found that these galaxies are located at the distances of 6.6, 6.8 and 3.9 Mpc. The values obtained substantially differ from the distances to these same galaxies (3.4, 3.5 and 3.5 Mpc), measured by Wu et al. in 2014 using the same images. The measurements we carried out show that Maffei 1 and Maffei 2 do not form a single group with the IC 342 galaxy, as previously thought. [ABSTRACT FROM AUTHOR]

This paper presents the operational cloud retrieval algorithms for the TROPOspheric Monitoring Instrument (TROPOMI) on board the European Space Agency Sentinel-5 Precursor (S5P) mission scheduled for launch in 2017. Two algorithms working in tandem are used for retrieving cloud properties: OCRA (Optical Cloud Recognition Algorithm) and ROCINN (Retrieval of Cloud Information using Neural Networks). OCRA retrieves the cloud fraction using TROPOMI measurements in the ultraviolet (UV) and visible (VIS) spectral regions, and ROCINN retrieves the cloud top height (pressure) and optical thickness (albedo) using TROPOMI measurements in and around the oxygen A-band in the near infrared (NIR). Cloud parameters from TROPOMI/S5P will be used not only for enhancing the accuracy of trace gas retrievals but also for extending the satellite data record of cloud information derived from oxygen A-band measurements, a record initiated with the Global Ozone Monitoring Experiment (GOME) on board the second European Remote-Sensing Satellite (ERS-2) over 20 years ago. The OCRA and ROCINN algorithms are integrated in the S5P operational processor UPAS (Universal Processor for UV/VIS/NIR Atmospheric Spectrometers), and we present here UPAS cloud results using the Ozone Monitoring Instrument (OMI) and GOME-2 measurements. In addition, we examine anticipated challenges for the TROPOMI/S5P cloud retrieval algorithms, and we discuss the future validation needs for OCRA and ROCINN. [ABSTRACT FROM AUTHOR]

We use observations of surface and top-of-the-atmosphere (TOA) broadband radiation fluxes determined from the Atmospheric Radiation Measurement programme mobile facility, the Geostationary Earth Radiation Budget (GERB) and Spinning Enhanced Visible and Infrared Imager (SEVIRI) instruments and a range of meteorological variables at a site in the Sahel to test the ability of the ECMWF Integrated Forecasting System cycle 43r1 to describe energy budget variability. The model has daily average biases of -12 and 18W m-2 for outgoing longwave and reflected shortwave TOA radiation fluxes, respectively. At the surface, the daily average bias is 12(13)W m-2 for the longwave downwelling (upwelling) radiation flux and -21(-13)W m-2 for the shortwave downwelling (upwelling) radiation flux. Using multivariate linear models of observation-model differences, we attribute radiation flux discrepancies to physical processes, and link surface and TOA fluxes. We find that model biases in surface radiation fluxes are mainly due to a low bias in ice water path (IWP), poor description of surface albedo and model-observation differences in surface temperature. We also attribute observed discrepancies in the radiation fluxes, particularly during the dry season, to the misrepresentation of aerosol fields in the model from use of a climatology instead of a dynamic approach. At the TOA, the low IWP impacts the amount of reflected shortwave radiation while biases in outgoing longwave radiation are additionally coupled to discrepancies in the surface upwelling longwave flux and atmospheric humidity. [ABSTRACT FROM AUTHOR]

The populations of conformers of ibuprofen in supercritical CO 2 have been calculated for two isochors in the temperature range of 35–90 °C, using the combination of data of IR spectroscopy, quantum chemical calculations and molecular dynamics simulation (metadynamics approach). The results of 2D cross-correlation analysis of IR spectra confirm the presence of two spectral contributions associated with two conformers. The population of the first conformer ( Conf. I ) is found to be dominating within the investigated temperature range. Moreover, at the temperature of 60 °C, for both studied isochors, the population of the first conformer reaches the maximum. The assumption about the correlation between the populations of conformers in supercritical media and population of polymorphs, which form during crystallization from certain initial state parameters, has been formulated and checked using analysis of micronized ibuprofen powder obtained by the method of rapid expansion of supercritical solution (RESS). The analysis of the microcrystalline ibuprofen, obtained by RESS, was performed by Differential Scanning Calorimetry (DSC) and X-Ray Powder Diffraction (XRPD). Both methods lead to estimation of the polymorphs populations in accordance with the conformer populations at corresponding state parameters. [ABSTRACT FROM AUTHOR]

Global apparent short wave infrared (SWIR) (1.64-1.66 μm) albedo mapping results from data acquired by Methane Sensor for Mars (MSM) onboard Indian Mars Orbiter Mission from October 2014 to February 2015, are presented. Global analysis of low and high albedo patterns is discussed using MSM apparent SWIR albedo map. The occurrence frequency of MSM apparent SWIR albedo shows a clear bimodal behaviour and is in good agreement with OMEGA NIR albedo distribution. Based on MSM apparent SWIR albedo values, three classes (high, intermediate and low albedo values) are defined, which show a clear elevation dependency. Variation of weekly average apparent albedo during the study period over Syrtis Major, Daedalia Planum and Valles Marineris region, respectively, is presented. [ABSTRACT FROM AUTHOR]

Much of the uncertainty in estimates of the anthropogenic forcing of climate change comes from uncertainties in the instantaneous effect of aerosols on cloud albedo, known as the Twomey effect or the radiative forcing from aerosol–cloud interactions (RFaci), a component of the total or effective radiative forcing. Because aerosols serving as cloud condensation nuclei can have a strong influence on the cloud droplet number concentration (Nd), previous studies have used the sensitivity of the Nd to aerosol properties as a constraint on the strength of the RFaci. However, recent studies have suggested that relationships between aerosol and cloud properties in the present-day climate may not be suitable for determining the sensitivity of the Nd to anthropogenic aerosol perturbations. Using an ensemble of global aerosol–climate models, this study demonstrates how joint histograms between Nd and aerosol properties can account for many of the issues raised by previous studies. It shows that if the anthropogenic contribution to the aerosol is known, the RFaci can be diagnosed to within 20% of its actual value. The accuracy of different aerosol proxies for diagnosing the RFaci is investigated, confirming that using the aerosol optical depth significantly underestimates the strength of the aerosol–cloud interactions in satellite data. [ABSTRACT FROM AUTHOR]

We propose a method to refine geometry of 3D meshes from a consumer level depth camera, e.g. Kinect, by exploiting shading cues captured from an infrared (IR) camera. A major benefit to using an IR camera instead of an RGB camera is that the IR images captured are narrow band images that filter out most undesired ambient light, which makes our system robust against natural indoor illumination. Moreover, for many natural objects with colorful textures in the visible spectrum, the subjects appear to have a uniform albedo in the IR spectrum. Based on our analyses on the IR projector light of the Kinect, we define a near light source IR shading model that describes the captured intensity as a function of surface normals, albedo, lighting direction, and distance between light source and surface points. To resolve the ambiguity in our model between the normals and distances, we utilize an initial 3D mesh from the Kinect fusion and multi-view information to reliably estimate surface details that were not captured and reconstructed by the Kinect fusion. Our approach directly operates on the mesh model for geometry refinement. We ran experiments on our algorithm for geometries captured by both the Kinect I and Kinect II, as the depth acquisition in Kinect I is based on a structured-light technique and that of the Kinect II is based on a time-of-flight technology. The effectiveness of our approach is demonstrated through several challenging real-world examples. We have also performed a user study to evaluate the quality of the mesh models before and after our refinements. [ABSTRACT FROM AUTHOR]

The ground-based characteristics (optical and radiative properties) of dust aerosols measured during the springtime between 2001 and 2014 were investigated over urban Beijing, China. The seasonal averaged aerosol optical depth (AOD) during spring of 2001-2014 was about 0.78 at 440 nm. During dust days, higher AOD occurred associated with lower Ångström exponent (AE). The mean AE in the springtime was about 1.0, indicating dominance of fine particles over the region. The back-trajectory analysis revealed that the dust was transported from the deserts of Inner Mongolia and Mongolia arid regions to Beijing. The aerosol volume size distribution showed a bimodal distribution pattern, with its highest peak observed in coarse mode for all episodes (especially for dust days with increased volume concentration). The single scattering albedo (SSA) increased with wavelength on dust days, indicating the presence of more scattering particles. Furthermore, the complex parts (real and imaginary) of refractive index showed distinct characteristics with lower imaginary values (also scattering) on dust days. The shortwave (SW; 0.2-4.0 μm) and longwave (LW; 4-100 μm) aerosol radiative forcing (ARF) values were computed from the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model both at the top of atmosphere (TOA) and the bottom of atmosphere (BOA) during dust and non-dust (dust free) days, and the corresponding heating rates and forcing efficiencies were also estimated. The SW (LW) ARF, therefore, produced significant cooling (warming) effects at both the TOA and the BOA over Beijing. [ABSTRACT FROM AUTHOR]

This research examines uncertainty in MODerate resolution Imaging Spectroradiometer (MODIS) observations, and demonstrates the direct influence of geometric distortions resulting from the standard practice of geolocating swath observations. MODIS observations vary dependent on the ground sample distance, which varies dependent on the view zenith angle that changes with every orbit. MODIS Level 2G (L2G) land products are generated by applying a geolocation algorithm that resamples the variable observation geometries to a consistent grid of fixed pixel size and location, a process which itself introduces variability associated with the changing observational footprint. For this study, broadband albedo was simulated for five validation sites, representing five distinct land cover types, exhibiting quantifiable variability, with additional seasonal variability exhibited in some sites. All site simulations exhibit compounded uncertainty attributable to the geometric distortion sufficient to influence climate models (i.e. ranges from 0.01 to 0.045 albedo). These results indicate there is a minimum level of uncertainty associated with the variable geometry that should be factored into L2G-based products, particularly for nominal 250 m band data. Aggregating the data to coarser resolutions and smoothing the data through average resampling can mitigate the uncertainty. [ABSTRACT FROM PUBLISHER]

High quality data of surface radiation is a prerequisite for climate monitoring (Earth radiation budget) and solar energy applications. A very common method to derive solar surface irradiance is the Heliosat method, a one channel approach for the retrieval of the effective cloud albedo (CAL). This information is then used to derive the solar surface irradiance by application of a clear sky model. The results of this study are based on radiative transfer modelling, visual inspection of satellite images and evaluation of satellite based solar surface radiation with ground measurements. The respective results provide evidence that variations in Aerosol Optical depth induced by desert storms and biomass burning events lead to a significant increase of the effective cloud albedo, thus, that certain aerosol events are interpreted as clouds by the method. For the estimation of the solar surface radiation aerosol information is needed as input for the clear sky model. As the aerosol effect is partly considered by CAL, there is a need to modify external aerosol information for the use within the clear sky model, e.g., by truncation of high aerosol loads. Indeed, it has been shown that a modified version of the Monitoring Atmospheric Composition and Climate (MACC) aerosol information leads to better accuracy of the retrieved solar surface radiation than the original MACC data for the investigated 9 sites and time period (2006-2009). Further, the assumption of a constant aerosol optical depth of 0.18 provides also better accuracies of the estimated solar surface radiation than the original MACC data for the investigated sites and period. It is concluded that this is partly due to the consideration of scattering aerosols by the effective cloud albedo. [ABSTRACT FROM AUTHOR]

We present a new analysis of Spitzer observations of Comet 29P/Schwassmann–Wachmann 1 taken on UT 2003 November 21, 23, and 24, similar to a previous investigation of the observations (Stansberry et al., 2004), but using the most recent Spitzer data pipeline products and intensive image processing techniques. Analysis of images from the IRAC 5.8 and 8.0 μ m bands and the MIPS 24.0 and 70.0 μ m bands resulted in photometry measurements of the nucleus after a suite of coma modeling and removal processes were implemented. SW1 was not identified in the 5.8 μ m image from the previous work so its incorporation into this analysis is entirely new. Using the Near Earth Asteroid Thermal Model (Harris, 1998) resulted in a nucleus radius measurement of R = 30.2 - 2.9 + 3.7 km and an infrared beaming parameter value of η = 0.99 - 0.19 + 0.26 . We also measured an infrared geometric albedo, p 5.8 = 0.5 ± 0.5 . Extrapolating a 0.04 V-band albedo and using a normalized reflectivity gradient S ′ = 14.94 ± 1.09 [% (1000 Å) −1 ] (Duffard, R., et al. [2014]. Astron. Astrophys. 564, A92) we recover an infrared albedo of p 5.8 = 0.31 in the near infrared consistent with the value recovered from thermal modeling. The dust composition extracted from IRS spectra are very comet-like, containing mainly amorphous ferromagnesian silicates (but with a minority of crystalline silicates as well), water ice, and metal sulfides. [ABSTRACT FROM AUTHOR]

A strong diurnal variation of aerosol has been observed in many heavily polluted regions in China. This variation could affect the direct aerosol radiative forcing (DARF) evaluation if the daily averaged value is used as normal rather than the time-resolved values. To quantify the effect of using the daily averaged DARF, 196 days of high temporal resolution ground-based data collected in SKYNET Hefei site during the period from 2007 to 2013 is used to perform an assessment. We demonstrate that strong diurnal changes of heavy aerosol loading have an impact on the 24-haveraged DARF when daily averaged optical properties are used to retrieve this quantity. The DARF errors varying from - 7.6 to 15.6 W m-2 absolutely and from 0.1 to 28.5 % relatively were found between the calculations using daily aver-age aerosol properties, and those using time-resolved aerosol observations. These errors increase with increasing daily aerosol optical depth (AOD) and decreasing daily single-scattering albedo (SSA), indicating that the high temporal resolution DARF data set should be used in the model instead of the normal daily-averaged one, especially under heavy aerosol loading conditions for regional campaign studies. We also found that statistical errors (0.3 W m-2 absolutely and 11.8 % relatively) will be less, which means that the effect of using the daily averaged DARF can be weakened by using a long-term observational data set. [ABSTRACT FROM AUTHOR]

A large decrease in the land surface albedo of the Loess Plateau was observed from 2000 to 2010, as measured using satellite imagery. In particular, ecological restoration program regions experienced a decrease in peak season land surface albedo exceeding 0.05. In this study, we examined the spatial and temporal patterns of variation during the peak season albedo in the Loess Plateau and analyzed its relationships with changes of anthropogenic and natural factors at the pixel level. Our analysis revealed that increasing grassland coverage due to returning rangeland to grassland could lead to a maximum albedo decrease of 0.030 in peak season. This result highlighted the human-induced land use change in driving the decreasing albedo on an annual scale. There was no significant correlation between precipitation change and albedo reduction. Precipitation could influence the spatial pattern of albedo in drought years by influencing the natural vegetation water requirement. However, the role of precipitation was not obvious in the ecological restoration program regions. This article demonstrates the substantial role that land use change could play in regional-scale albedo change and climate. Finally, some implications for the radiative forcing of land use change are discussed. [ABSTRACT FROM AUTHOR]

The distribution of near-Earth asteroid ( NEA) rotation rates differs considerably from the similar distribution of Main Belt asteroids ( MBAs) by the presence of excesses of fast and slow rotators, which are not observed or not so prominent in the distribution for MBAs. Among possible reasons for the difference, there can be influence of solar radiation on spin rate of small NEAs, the so-called ' YORP effect,' which appears due to reflection, absorption, and IR re-emission of the sunlight by an irregularly shaped rotating asteroid. It is known that the YORP-effect action strongly depends on the amount of solar energy obtained by the body (insolation), its size, and albedo. The analysis of observation data has shown that: (1) the mean diameter of NEAs decreases from the middle of the distribution to its ends, that is, the excesses of slow rotators (ω ≤ 2 rev day−1) and fast rotators (ω ≥ 8 rev day−1) are composed of smaller NEAs than in the middle of the distribution; (2) NEAs of both excesses are in the orbits where their insolation is about 8-10% larger than that of NEAs in the middle of the distribution; and (3) the objects in both excesses have a little lower albedo on average than that of objects in the middle of the distribution. All these results qualitatively agree well with the YORP-effect action and may be considered as independent arguments in favor of it. [ABSTRACT FROM AUTHOR]

We use a linear unmixing approach to test how land use and forestry maps, in combination with the MODIS BRDF/albedo product, can be used to estimate land cover type albedos in boreal regions. Operational land use maps from three test areas in Finland and Canada were used to test the method. The resulting endmember albedo estimates had low standard errors of the mean and were realistic for the main land cover types. The estimated albedos were fairly consistent with albedo measurements conducted with a telescope mast and pure pixel albedos. Problems with the method are the possible errors in the land cover maps, lack of good quality winter MODIS albedo composites and the mismatch between the MODIS pixels and the true observation area. The results emphasize the role of tree species as determinant of forest albedo. Comprehensive spatial and temporal measurements of land cover albedo are usually not possible with in situ mast measurements, and the spatial resolution of MODIS albedo product is often too low to allow direct comparison of pixel albedos and land cover types in areas with heterogeneous vegetation. Hence, and since local forestry maps exist for most temperate and boreal regions, we believe that the proposed method will be useful in estimating average regional land cover type albedos as well as in tracking changes in them. [ABSTRACT FROM AUTHOR]

Aims. We use the super Earth 55 Cnc e as a case study to address an observable effect of tidal heating. This transiting short-period planet belongs to a compact multiple system with massive planets. We investigate whether planet-planet interactions can force the eccentricity of this planet to a level affecting the eclipse depth observed with Spitzer. Methods. Using the constant time lag tidal model, we first calculate the observed planet flux as a function of albedo and eccentricity, for different tidal dissipation constants and for two extreme cases: a planet with no heat redistribution and a planet with full heat redistribution. We derive the values of albedo and eccentricity that match the observed transit depth. We then perform N-body simulations of the planetary system including tides and general relativity to follow the evolution of the eccentricity of planet e. We compare the range of eccentricities given by the simulations with the eccentricities required to alter the eclipse depth. Results. Using our nominal value for the dissipation constant and the most recent estimates of the orbital elements and masses of the 55 Cnc planets, we find that the eccentricity of planet e can be large enough to contribute at a measurable level to the thermal emission measured with Spitzer. This affects the constraints on the albedo of the planet, which can be as high as 0.9 (instead of 0.55 when ignoring tidal heating). We also derive a maximum value for the eccentricity of planet e directly from the eclipse depth: e < 0.015 assuming Earth's dissipation constant. Conclusions. Transiting exoplanets in multiple planet systems - like 55 Cancri - are exceptional targets for testing tidal models because their tidal luminosity may be observable. Future multi-wavelengths observations of eclipse depth and phase curves (for instance with EChO and JWST) should allow us to better resolve the temperature map of these planets and break the degeneracy between albedo and tidal heating that remains for single band observations. In addition, an accurate determination of the eccentricity will make it possible to constrain the dissipation rate of the planet and to probe its internal structure. [ABSTRACT FROM AUTHOR]

In the Nice model, the late heavy bombardment (LHB) is related to an orbital instability of giant planets which causes a fast dynamical dispersion of a trans-Neptunian cometary disk. We study effects produced by these hypothetical cometary projectiles on main belt asteroids. In particular, we want to check whether the observed collisional families provide a lower or an upper limit for the cometary flux during the LHB.We present an updated list of observed asteroid families as identified in the space of synthetic proper elements by the hierarchical clustering method, colour data, albedo data and dynamical considerations and we estimate their physical parameters. We selected 12 families which may be related to the LHB according to their dynamical ages. We then used collisional models and N-body orbital simulations to gain insight into the long-term dynamical evolution of synthetic LHB families over 4 Gyr. We account for the mutual collisions between comets, main belt asteroids, and family members, the physical disruptions of comets, the Yarkovsky/YORP drift in semimajor axis, chaotic diffusion in eccentricity/inclination, or possible perturbations by the giantplanet migration. Assuming a "standard" size-frequency distribution of primordial comets, we predict the number of families with parent-body sizes DPB ⩾ 200 km - created during the LHB and subsequent ≃4Gyr of collisional evolution - which seems consistent with observations. However, more than 100 asteroid families with DPB ⩾ 100 km should be created at the same time which are not observed. This discrepancy can be nevertheless explained by the following processes: i) asteroid families are efficiently destroyed by comminution (via collisional cascade), ii) disruptions of comets below some critical perihelion distance (q ≲ 1.5AU) are common. Given the freedom in the cometary-disruption law, we cannot provide stringent limits on the cometary flux, but we can conclude that the observed distribution of asteroid families does not contradict with a cometary LHB. [ABSTRACT FROM AUTHOR]

Climate has been recognized to have direct and indirect impact on society and economy, both in the long term and daily life. The challenge of understanding the climate system, with its variability and changes, is enormous and requires a joint long-term international commitment from research and governmental institutions. An important international body to coordinate worldwide climate monitoring efforts is the World Meteorological Organization (WMO). The Global Climate Observing System (GCOS) has the mission to provide coordination and the requirements for global observations and essential climate variables (ECVs) to monitor climate changes. The WMO-led activity on Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM) is responding to these requirements by ensuring a continuous and sustained generation of climate data records (CDRs) from satellite data in compliance with the principles and guidelines of GCOS. SCOPE-CM represents a new partnership between operational space agencies to coordinate the generation of CDRs. To this end, pilot projects for different ECVs, such as surface albedo, cloud properties, water vapor, atmospheric motion winds, and upper-tropospheric humidity, have been initiated. The coordinated activity on land surface albedo involves the operational meteorological satellite agencies in Europe [European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT)], in Japan [the Japan Meteorological Agency (JMA)], and in the United States [National Oceanic and Atmospheric Administration (NOAA)]. This paper presents the first results toward the generation of a unique land surface albedo CDR, involving five different geostationary satellite positions and approximately three decades of data starting in the 1980s, and combining close to 30 different satellite instruments. INSET: SATELLITE DATA ARCHIVES: JMA, EUMETSAT, AND NOAA. [ABSTRACT FROM AUTHOR]

Abstract: Laboratory spectra have shown that CO2 is a powerful diagnostic tool for analyzing infrared data from remote observations, as it has been detected on icy moons in the outer Solar System as well as dust grain surfaces in the interstellar medium (ISM). IR absorption band profiles of CO2 within ice mixtures containing H2O and CH3OH change with respect to temperature and mixture ratios. In this particular study, the ν 3 CO2 asymmetric stretch mode near 4.3μm (2350cm−1), overtone mode near 1.97μm (5080cm−1), and the combination bands near 2.7μm (3700cm−1), 2.8μm (3600cm−1), and 2.02μm (4960cm−1), are systematically observed in different mixtures with H2O and CH3OH in temperature ranges from 15K to 150K. Additionally, some high-temperature deposits (T >50K) of H2O, CH3OH, and CO2 ice mixtures were performed and it was discovered that CO2 may deposit out at higher temperatures than previously recorded. These data may then be used to interpret infrared observational data obtained from icy surfaces in the outer Solar System and beyond. [Copyright &y& Elsevier]

A new visible (VIS; 0.55-0.9 μm) albedo normalization method, that is, the quasi-Lambertian surface adjustment (QLSA), is developed herein by using the geostationary meteorological satellite data and radiative transfer model. Taking the variation of relative locations between the sun, satellite, and clouds into account, the QLSA effectively reduces the inconsistencies in the VIS image brightness caused by the Lambertian surface approximation to cloud tops (i.e., the reflection characteristic is isotropic). The evaluation, using Chinese and Japanese geostationary satellite data, shows that the QLSA is more effective and accurate than three other albedo normalization methods currently in use. The new algorithm is applicable in regions with solar zenith angle and satellite zenith angle less than 60°, which, in the summertime, approximately corresponds to the time range from 0800 to 1600 local time (LT). [ABSTRACT FROM AUTHOR]

In this study, we have adopted an approach for objective optimization of the selection of band ratios in forming Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) band ratio composites, based on factor analysis loadings and specific variances. The factor loadings and specific variances of all 72 possible spectral band ratios of the visible and near infrared (VNIR) and the short-wave infrared (SWIR) of ASTER data from Wadi Kid, southeastern Sinai Peninsula, Egypt, were utilized to construct two separate rankings of band ratios in an ascending manner in order to determine the best ASTER band ratio combinations for lithological mapping in the study area. Two ASTER band ratio composites ((band 6/band 3–band 1/band 3–band 9/band 5) and (8/6–8/7–4/7) in blue–green–red (BGR)) were built, based on the rankings of factor loadings and specific variances, respectively. These two composites were fused together based on a discrete wavelet transform (DWT) decomposition, which enables decomposition of an image into (high-pass) details and (low-pass) approximations at various levels of resolution, resulting in improved lithological discrimination of granitic and meta-sediments rock units and a reduction in the BGR imprints of topographic reliefs. [ABSTRACT FROM AUTHOR]

Projection-based appearances are used in a variety of computer graphics applications to impart different appearances onto physical surfaces using digitally controlled projector light. To achieve a compliant appearance, all points on the physical surface must be altered to the colours of the desired target appearance; otherwise, an incompliant appearance results in a misleading visualization. Previous systems typically assume to operate with compliant appearances or restrict themselves to the simpler case of white surfaces. To achieve compliancy, one may change the physical surface's albedo, increase the amount of projector light radiance available or modify the target appearance's colours. This paper presents an approach to modify a target appearance to achieve compliant appearance editing without altering the physical surface or the projector setup. Our system minimally alters the target appearance's colours while maintaining cues important for perceptual similarity (e.g. colour constancy). First, we discuss how to measure colour compliancy. Next, we describe our approach to partition the physical surface into patches based on the surface's colours and the target appearance's colours. Finally, we describe our appearance optimization process, which computes a compliant appearance that is as perceptually similar as possible to the target appearance's colours. We perform several real-world projection-based appearances and compare our results to naïve approaches, which either ignore compliancy or simply reduce the appearance's overall brightness. [ABSTRACT FROM AUTHOR]

Characterization of exoplanets has matured in recent years, particularly through studies of exoplanetary atmospheres of transiting planets at infrared wavelengths. The primary source for such observations has been the Spitzer Space Telescope but these studies are anticipated to continue with the James Webb Space Telescope. A relatively unexplored region of exoplanet parameter space is the thermal detection of long-period eccentric planets during periastron passage. Here we describe the thermal properties and albedos of long-period giant planets along with the eccentricities of those orbits which allow them to remain within the habitable zone. We further apply these results to the known exoplanets by calculating temperatures and flux ratios for the IRAC passbands occupied by warm Spitzer, considering both low and high thermal redistribution efficiencies from the perspective of an observer. We conclude with recommendations on which targets are best suited for follow-up observations. [ABSTRACT FROM AUTHOR]

Abstract: The diffuse reflectance (albedo) and transmittance of a Raman random gain medium are derived from a diffusion equation with power dependent gain. The results show good agreement with the experimental data for barium nitrate powder. Both the Raman albedo AR and Raman transmittance TR diverge at a critical gain γc, interpreted as the threshold for diffusive Raman laser generation. The parametric dependence of the albedo and threshold gain on the scattering characteristics of the random medium is analysed and the feedback effect of Fresnel reflection at the gain boundaries evaluated. The addition of external mirrors, particularly at the pumped surface, significantly reduces the generation threshold. [Copyright &y& Elsevier]

The article presents a study which examines the vertical profile of the snow's specific surface area (SSA) and density at Dome C and Dumont D'Urville in Antarctica. The study assesses the infrared (IR) reflectance of snow at 1310 nanometers using the dual-frequency integrating sphere for snow (DUFISS) system. It is found out that the vertical profile of SSA and density can be used in calculating the spectral albedo of the snow for several illumination conditions.

Abstract: Comet 133P/Elst-Pizarro, known to be a main-belt asteroid with a cometary activity, was observed with the near-infrared integral field spectrograph SINFONI at the 8.2-m Very Large Telescope in J, H, and K bands during its 2007 perihelion passage. The goal of these observations was to attempt detection of water ice absorption bands. We present here the details of the data processing, the results of these observations, and our compositional modeling of the final spectrum. No water ice absorptions were detected within the noise of the spectrum but we show that this spectrum is compatible with a reasonable near-infrared albedo value of 7–10% and a mixture of water ice, black carbon, Tholin and silicates. This interpretation, nevertheless, is not unique. [ABSTRACT FROM AUTHOR]

Abstract: The Cassini Huygens mission provides a unique opportunity to combine ground-based and spacecraft investigations to increase our understanding of chemical and dynamical processes in Titan’s atmosphere. Spectroscopic measurements from both vantage points enable retrieving global wind structure, temperature structure, and atmospheric composition. An updated analysis of Titan data obtained with the NASA Goddard Space Flight Center’s Infrared Heterodyne Spectrometer (IRHS) and Heterodyne Instrument for Planetary Wind and Composition (HIPWAC) prior to and during the Cassini Huygens mission is compared to retrievals from measurements with the Cassini Composite Infrared Spectrometer (CIRS). IRHS/HIPWAC results include the first direct stratospheric wind measurements on Titan, constraints on stratospheric temperature, and the study of atmospheric molecular composition. These results are compared to CIRS retrievals of wind and temperature profile from thermal mapping data and ethane abundance at 10–15° South latitude, near the equatorial region. IRHS/HIPWAC wind results are combined with other direct techniques, stellar occultation measurements, and CIRS results to explore seasonal variability over nearly one Titan year and to provide an empirical altitude profile of stratospheric winds, varying from ∼50 to 210m/s prograde. The advantage of fully resolved line spectra in species abundance measurements is illustrated by comparing the possible effect on retrieved ethane abundance by blended spectral features of other molecular constituents, e.g., acetylene (C2H2), ethylene (C2H4), allene (C3H4), and propane (C3H8), which overlap the ν 9 band of ethane, and are not resolved at lower spectral resolution. IR heterodyne spectral resolution can discriminate weak spectral features that overlap the ν9 band of ethane, enabling ethane lines alone to be used to retrieve abundance. Titan’s stratospheric mean ethane mole fraction (8.6±3ppmv) retrieved from IRHS/HIPWAC emission line profiles (resolving power λ⧸Δλ∼106) is compared to past values obtained from lower resolution spectra and from CIRS measurements (resolving power λ⧸Δλ∼2×103) and more compatible recent analysis. Results illustrate how high spectral resolution ground-based studies complement the spectral and spatial coverage and resolution of moderate spectral resolution space-borne spectrometers. [Copyright &y& Elsevier]

Abstract: This investigation uses linear mixture modeling employing cryogenic laboratory reference spectra to estimate surface compositions and water ice grain sizes of Europa’s ridged plains and smooth low albedo plains. Near-infrared spectra for 23 exposures of ridged plains materials are analyzed along with 11 spectra representing low albedo plains. Modeling indicates that these geologic units differ both in the relative abundance of non-ice hydrated species and in the abundance and grain sizes of water ice. The background ridged plains in our study area appear to consist predominantly of water ice (∼46%) with approximately equal amounts (on average) of hydrated sulfuric acid (∼27%) and hydrated salts (∼27%). The solutions for the smooth low albedo plains are dominated by hydrated salts (∼62%), with a relatively low mean abundance of water ice (∼10%), and an abundance of hydrated sulfuric acid similar to that found in ridged plains (∼27%). The model yields larger water ice grain sizes (100μm versus 50–75μm) in the ridged plains. The 1.5-μm water ice absorption band minimum is found at shorter wavelengths in the low albedo plains deposits than in the ridged plains (1.498±.003μm versus 1.504±.001μm). The 2.0-μm band minimum in the low albedo plains exhibits a somewhat larger blueshift (1.964±.006μm versus 1.983±.006μm for the ridged plains). The study area spans longitudes from 168° to 185°W, which includes Europa’s leading side–trailing side boundary. A well-defined spatial gradient of sulfuric acid hydrate abundance is found for both geologic units, with concentrations increasing in the direction of the trailing side apex. We associate this distribution with the exogenic effects of magnetospheric charged particle bombardment and associated chemical processing of surface materials (the radiolytic sulfur cycle). However, one family of low albedo plains exposures exhibits sulfuric acid hydrate abundances up to 33% lower than found for adjacent exposures, suggesting that these materials have undergone less processing, thus implying that these deposits may have been emplaced more recently. Modeling identifies high abundances (to 30%) of magnesium sulfate brines in the low albedo plains exposures. Our investigation marks the first spectroscopic identification of MgSO4 brine on Europa. We also find significantly higher abundances of sodium-bearing species (bloedite and mirabilite) in the low albedo plains. The results illuminate the role of radiolytic processes in modifying the surface composition of Europa, and may provide new constraints for models of the composition of Europa’s putative subsurface ocean. [Copyright &y& Elsevier]

Abstract: Since the Saturn orbit insertion of the Cassini spacecraft in mid-2004, the Cassini composite infrared spectrometer (CIRS) measured temperatures of Saturn’s main rings at various observational geometries. In the present study, we apply our new thermal model (Morishima, R., Salo, H., Ohtsuki, K. [2009]. Icarus 201, 634–654) for fitting to the early phase Cassini data (Spilker, L.J., and 11 colleagues [2006]. Planet. Space Sci. 54, 1167–1176). 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. We estimated the bolometric Bond albedo, A V, the fraction of fast rotators in cross section, f fast, and the thermal inertia, Γ, by the data fitting at every radius from the inner C ring to the outer A ring. The albedo A V 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 f fast depends on the ratio of scale height of fast rotators to that of slow rotators, h r. When h r =1, f fast is roughly half for the entire rings, except for the A ring, where f fast increases from 0.5 to 0.9 with increasing saturnocentric radius. When h r increases from 1 to 3, f fast decreases by 0.2–0.4 for the B and A rings while no change in f fast is seen for the optically thin C ring and Cassini division. The large f fast seen in the outer A ring probably indicates that a large number of small particles detach from large particles in high velocity collisions due to satellite perturbations or self-gravity wakes. The thermal inertia, Γ, is constrained from the efficiency of the vertical heat transport due to particle motion between the lit and unlit faces, and is coupled with the type of vertical motion. We found that in most regions, except for the mid B ring, sinusoidal vertical motion without bouncing is more reasonable than cycloidal motion assuming bouncing at the midplane, because the latter motion gives too large Γ as compared with previous estimations. For the mid B ring, where the optical depth is highest in Saturn’s rings, cycloidal vertical motion is more reasonable than sinusoidal vertical motion which gives too small Γ. [Copyright &y& Elsevier]

We prove the renormalizability of a quark–gluon model with soft breaking of the BRST symmetry, which accounts for the modification of the large distance behavior of the quark and gluon correlation functions. The proof is valid to all orders of perturbation theory, by making use of softly broken Ward identities. [ABSTRACT FROM AUTHOR]

Abstract: Radiative transfer is computationally expensive. However, it is essential to many applications, in particular remote sensing retrievals. Principal component analysis of the optical depth and single scattering albedo profiles has been proposed as a possible method to help ease the computational burden. Here we show how the technique could be applied to a practical problem of CO2 retrievals from high spectral resolution measurements of reflected sunlight in three near infrared bands. We obtain a speed improvement of more than 50 fold (compared to monochromatic computations), while reproducing the radiances to better than 0.1% accuracy. [Copyright &y& Elsevier]

Infrared (IR) data from the Meteosat Second Generation (MSG) satellite are used to understand cloud-top signatures for growing cumulus clouds prior to known convective initiation (CI) events, or the first occurrence of a ≥35-dB Z echo from a new convective cloud. In the process, this study proposes how MSG IR fields may be used to infer three physical attributes of growing cumuli, cloud depth, cloud-top glaciation, and updraft strength, with limited information redundancy. These three aspects are observed as unique signatures within MSG IR data, for which this study seeks to relate to previous research, as well as develop a new understanding on which subset of IR information best identifies these attributes. Data from 123 subjectively identified CI events observed during the 2007 Convection and Orograpically Induced Precipitation Study (COPS) field experiment conducted over southern Germany and northeastern France are processed, per convective cell, to meet this study’s objectives. A total of 67 IR “interest fields” are initially assessed for growing cumulus clouds, with correlation and principal component analyses used to highlight the top 21 fields that are considered the best candidates for describing the three attributes. Using between 6 and 8 fields per category, a method is then proposed on how growing convective clouds may be quantified per 3-km2 pixel (or per cumulus cloud object) toward inferring each attribute. No independent CI-nowcasting analysis is performed, which instead is the subject of ongoing research. [ABSTRACT FROM AUTHOR]

The Earth's atmosphere has a natural greenhouse effect, without which the global mean surface temperature would be about 33 °C lower and life would not be possible. Human activities have increased atmospheric concentrations of carbon dioxide, methane, and other gases in trace amounts. This has enhanced the greenhouse effect, resulting in surface warming. Were it not for the partly offsetting effects of increased aerosol concentrations, the increase in global mean surface temperature over the past 100 years would be larger than observed. Continued surface warming through the 21st century is inevitable and will likely have widespread ecological impacts. The magnitude and rate of warming for the global average will be largely dictated by the strength and direction of climate feedbacks, thermal inertia of the oceans, the rate of greenhouse gas emissions, and aerosol concentrations. Because of regional expressions of climate feedbacks, changes in atmospheric circulation, and a suite of other factors, the magnitude and rate of warming and changes in other key climate elements, such as precipitation, will not be uniform across the planet. For example, due to loss of its floating sea-ice cover, the Arctic will warm the most. [ABSTRACT FROM AUTHOR]

The normal mode frequencies and corresponding vibrational assignments of tetrachloropalladate (II) ion ([Pd(Cl)4]2-) have been theoretically examined by means of standard quantum chemical technique. All normal modes have been successfully assigned utilizing the D4h symmetry of [Pd(Cl)4]2-. Calculation has been performed at the Becke-3-Lee-Yang-Parr (B3LYP) density functional method using the Lanl2dz basis set. Infrared intensity and Raman activities have also been calculated and reported. Theoretical results have been successfully compared against available experimental data. [ABSTRACT FROM AUTHOR]

Because there is an imminent danger that most of the existing expert knowledge about attitude determination using fan beam albedo sensors on spin-stabilized satellites may become unavailable, it seems worthwhile to summarize this material in an archival paper. Toward this goal, all still-accessible reports and notes dealing with attitude reconstitution based on albedo slit sensors have been scrutinized. On this basis, we assessed the state of the art that was reached some decades ago; subsequently, no new satellite projects were realized that made use of this still- interesting type of attitude sensors. In the analysis of the available material, it appeared that attitude measurement stability and estimation accuracy still faced problems during particular time periods. In this context, elements have been identified that had been omitted from the ground-based attitude operations. These elements essentially concern the exclusion of specific measurement geometries, which, with certainty, invalidated certain measurements during time intervals of nonnegligible duration. The reported estimation concepts of the past have been updated not only on a theoretical basis, but also in light of more recent insights and operational experience gained from infrared sensing on spinning satellites. All this is included in a comprehensive and self-contained presentation based on the geometry of fan beam albedo sensing and its practical operational implementation. [ABSTRACT FROM AUTHOR]

The effect of polyvinyl pyrrolidone (PVP) K30 and/or l-arginine on etoricoxib-HPβCD complex was investigated. The phase solubility profiles were classified as AL-type, both in absence or presence of auxiliary substances used. The apparent stability constant (Kc) of binary complex obtained at room temperature, 371.80 ± 2.61 M-1, was decreased with the addition of PVP and arginine indicating no benefit of addition of auxiliary substances to promote higher complexation efficiency. Therefore, solid etoricoxib-HPβCD binary systems were prepared and characterized by proton nuclear magnetic resonance spectroscopy (1HNMR), X-ray powder diffractometry, Fourier transformation-infrared spectroscopy, and dissolution studies. Among all binary systems, a lyophilized product showed superior performance in enhancing dissolution of etoricoxib. [ABSTRACT FROM AUTHOR]

When the Earth's surface warms and emits long-wave infrared (IR) radiation, IR active gases (e.g. CO2, CH4, etc.) effectively absorb it; CO2 is therefore one of the major challenges facing the climate research community. However, in Europe recent radiation measurement over about a decade shows that rapid temperature increase is mainly (~65%) caused by water vapor. The following points are established through the main discussion: (i) there are a number of factors causing climate change (e.g. astronomical factors), that is, CO2 is just one of various climate drivers; (ii) the coupling complexity of CO2 with climate is enhanced by the time-scale extension; and (iii) this complexity involves various climate drivers with different cycles and magnitudes. The Earth's atmosphere has evolved over the last 4.5 billion years and still continues to evolve; thus, climate variability must be inevitable and complex. Future climate change may be drawn from the newly emerging discipline of complexity science. [ABSTRACT FROM AUTHOR]

Abstract: We present the results of a visible spectroscopic survey of igneous asteroids belonging to the small and intriguing E-class, including 2867 Steins, a target of the Rosetta mission. The survey was carried out at the 3.5 m Telescopio Nazionale Galileo (TNG), and at the 3.5 m New Technology Telescope (NTT) of the European Southern Observatory. We obtained new visible spectra for eighteen E-type asteroids, and near infrared spectra for eight of them. We confirm the presence of three different mineralogies in the small E-type populations. We classify each object in the E[I], E[II] or E[III] subgroups [Gaffey, M.J., Kelley, M.S., 2004. Lunar Planet. Sci. XXXV. Abstract 1812] on the basis of the spectral behavior and of the eventual presence of absorption features attributed to sulfides (such the 0.49 μm band, on E[II]), or to iron bearing silicates (0.9 μm band, on E[III]). We suggest that some asteroids (i.e. 64 Angelina, 317 Roxane, and 434 Hungaria), which show different spectral behavior comparing our data with those available in literature, have an inhomogeneous surface composition. 2867 Steins, a target of the Rosetta mission, shows a spectral behavior typical of the E[II] subgroup, as already suggested by Barucci et al. [Barucci, M.A., Fulchignoni, M., Fornasier, S., Dotto, E., Vernazza, P., Birlan, M., Binzel, R.P., Carvano, J., Merlin, F., Barbieri, C., Belskaya, I., 2005. Astron. Astrophys. 430, 313–317] and Fornasier et al. [Fornasier, S., Marzari, F., Dotto, E., Barucci, M.A., Migliorini, A., 2007. Astron. Astrophys. 474, 29–32]. Litva and 1990 TN1, initially classified as E-types, show a visible and near infrared behavior consistent with the olivine rich A-class asteroids, while 5806 Archieroy, also supposed to belong to the E-class, has a spectral behavior consistent with the S(V) classification following the Gaffey et al. [Gaffey, M.J., Burbine, T.H., Piatek, J.L., Reed, K.L., Chaky, D.A., Bell, J.F., Brown, R.H., 1993. Icarus 106, 573–602] classification scheme. To fully investigate the E-type population, we enlarged our sample including 6 E-type asteroids spectra available in literature, resulting in a total sample of 21 objects. The analysis of the spectral slope for the 3 different E-type subgroups versus the orbital elements show that E[III] members have the lowest mean spectral slope value inside the whole sample, and that they are located between 2.2–2.7 AU in low inclination orbits. E[II] members has the highest spectral slope inside the sample, half of them are located in the Hungaria region, 2 are NEA and 2 (64 Angelina and 2867 Steins), are in the main belt. A similar distribution is found for the 5 featureless E[I] members, located mainly in the Hungaria region (3 members), one in the middle main belt while one is a NEA (2004 VD17). Finally, for the five E-type asteroids observed both in the visible and near infrared range, plus 2867 Steins, we attempt to model their surface composition using linear geographical mixtures of no more than 3 components, selected from aubrite meteorites and correlated minerals. In particular we suggest that the aubrite Peña Blanca might have the E[III] Asteroid 317 Roxane as parent body, and that the aubrite ALH78113 might be related to the E[II] subgroup asteroids. [Copyright &y& Elsevier]

Near-infrared and mid-infrared broad band interferometric observations of young stellar objects trace the inner part of the warm dusty circumstellar environment (smaller than a few AUs) and can be used to constrain its physical properties, in particular to characterize the size, location and composition of the emitting region. Because the spatial frequency coverage of current instruments remain sparse, modeling, including detailed radiative transfer (RT), is necessary to get a precise estimate of these properties. [ABSTRACT FROM AUTHOR]

We present high spatial resolution observations of the mid-infrared core of the dusty symbiotic system HM Sge. The MIDI interferometer was used with the VLT Unit Telescopes and Auxiliary Telescopes providing baselines oriented from PA=42° to 105°. The MIDI visibilities are compared with the ones predicted in the frame of various spherical dust shells published in the literature involving single or double dusty shells intended to account for the influence of the hot White Dwarf. The mid-IR environment is unresolved by a 8m telescope and the MIDI spectrum exhibits a level similar to the ISO spectra recorded 10 yr ago. The discrepancies between the HWHM at different angle orientations suggest an increasing level of asymmetry from 13 to 8 μm. The observations are surprisingly well fitted by the densest (optically thick in the N band) and smallest spherical model published in the literature based on the ISO data, although such a model does not account for the variations of near-IR photometry due to the Mira pulsation cycle suggesting a much smaller optical thickness. These observations also discard the two shells models, developed in an attempt to take into account the effect of the White Dwarf illumination onto the dusty wind of the Mira. These models are too extended, and lead to a level of asymmetry of the dusty environment tightly constrained by the MIDI visibilities. These observations show that a high rate of dust formation is occurring in the vicinity of the Mira which seems to be not highly perturbed by the hot companion. [ABSTRACT FROM AUTHOR]

Sophisticated radiative transfer methods have been used for decades to model one-dimensional static stellar atmospheres. They predict an outward decrease of the atmospheric temperature that is now observable with simple one-baseline interferometers via measurements of limb darkening. However, the surface layers of many stars are affected by convection which requires a treatment by time-dependent multi-dimensional radiation hydrodynamics simulations. Solar granulation is directly observable with "ordinary" telescopes. The simulated granule pattern and evolution compares well with the observed ones. The upcoming radio interferometer ALMA could be used to probe the convection induced shock-pattern in the chromosphere that is predicted by simulations and that is not easily observable otherwise. The typical granular scale on other near main-sequence stars is too small to be accessible by interferometers. However, scaling arguments and recent numerical simulations predict very large structures on cool supergiants and AGB stars. These stars were and are candidates for optical/near-infrared interferometry. The complexity of the predicted surface phenomena requires good (or at least some) spatial resolution in conjunction with temporal and frequency resolution. To fully exploit and interpret these data the simulations have to be improved in terms of treatment of microphysics (especially opacities in the radiative transfer step) and spatial resolution. [ABSTRACT FROM AUTHOR]

The Very Large Telescope Interferometer on Cerro Paranal in Northern Chile is one of the largest optical facilities used in astronomy. It can combine two or three of the four 8.2 m and four movable 1.8m telescopes, which span baselines between 8 and 202m. Observations are carried out in the near- and mid-infrared, covering the wavelength range from 1 to 13 μm. [ABSTRACT FROM AUTHOR]

Grain size is a key parameter of a snowpack, affecting its thermodynamic state and influencing the spectral snow albedo. Differently from visible wavelengths, where the sensitivity to grain size is very low, in the near-infrared band there is a strong sensitivity of the reflectance to the grain size. This sensitivity provides the basis for the retrieval of grain size. In this paper we introduce a new snow retrieval algorithm that makes use of near-infrared measurements in which snow is modeled as a semi-infinite, weakly absorbing medium. It is assumed that the dense packing effects can be neglected and the radiative transport in snow can be studied using the standard radiative transfer equation extensively used, e.g., in cloud optics. The shape of grains is accounted for in the framework of fractal snow grain model. The performance of the algorithm is evaluated using ground-based measurements of snow albedo and results from a different retrieval algorithm. The technique is applied to study the changes of snow properties before and just after snow fall as seen by two MODIS sensors on TERRA and AQUA satellites. These satellites fly approximately 3 h and half apart (10:30 a.m. and 1:30 p.m. equator crossing time). The values of grain size retrieved from MODIS are also compared with values of grain size collected on ground. However, the area observed by MODIS including the locations of ground measurements was completely covered by clouds on the date of the measurements and the comparison could be performed only for the two previous days. A sensitivity analysis of the retrieval error due to atmospheric correction is also performed. Results show that the error on grain size retrieval induced by atmospheric correction ranges between ±5% and ±40%, depending on the grain size. [Copyright &y& Elsevier]

The article discusses the research on the effect of greenhouse warming to global warming. It was revealed that greenhouse warming generally recognized to be oversimplified but defend on the grounds that the general public would not be able to follow the correct treatment. In addition, greenhouse gases are defined to be those substances that are reasonably transparent in the visible but capable of absorbing and emitting in the infrared. Furthermore, subjective claims concerning the ability of current models to accurately portray natural unforced climate variability.

Purpose - This paper seeks to examine the dynamic problem of associating measurements at a given period from several IR sensors in the presence of clutter, missed detections. Design/methodology/approach - On the basis of a dynamic S-D assignment algorithm, a new association algorithm for associating and tracking multiple targets is presented. By considering the special feature of the IR sensor, the dynamic assignment cost coefficient incorporates the radiation intensity information into the association process using a joint probabilistic model for the two separate sources of information (intensity and trajectory). Findings - The simulation results show that the new algorithm can attain almost the same accuracy of tracking estimation with less computational load by utilizing special feature information of the IR sensor into dynamic S-D assignment. Research limitations/implications - There are still some parameters to be set in advance, which influence the estimate result to some extent. And the tracking stage follows the image processor, so the tracking performance is also related with the quality of images. Those problems will be considered deeply in the future research based on different maneuvering level of targets and the real tracking environment. Practical implications - This new algorithm may be adopted by tracking systems based on passive sensors in the future. Originality/value - This new algorithm utilizes more information and fairly small and stable errors in position and velocity can be obtained. At the same time, it decreases computational load. [ABSTRACT FROM AUTHOR]

Experimental data of infrared (IR) absorption measurements carried out on fast neutron irradiated carbon rich Cz–Si crystals were studied. Data from similar crystals, subjected prior to irradiation to thermal treatments at 1000 °C [(HT)] and thermal treatments at 1000 °C under high hydrostatic pressure [(HTHP)] of 11Kbar, were also studied. The time duration of both treatments was 5 h. After the irradiation the intensities of most of the observed bands were always stronger in the pre-treated material. Transformation of the defects upon post-irradiation isochronal anneals was investigated. Two out of six IR bands of the CiCs defect in the neutral charge state, at 543.5 and 635 cm−1, were detected at room temperature [(RT)]. It is argued that another two bands at 918 and 1006 cm−1 arising in the spectra upon annealing of the CiCs bands are associated with the same carbon-related structure giving rise to the Si-PT4 electron paramagnetic resonance (EPR) spectrum. A band at 533 cm−1 shows the same thermal evolution with a defect giving rise to the Si-P6 EPR spectrum attributed to a multi-interstitial cluster in silicon. Differences observed in the evolution curves of the CiCs(SiI) defect (987, 993 cm−1) between the as-grown and the pre-treated samples are considered and discussed. [ABSTRACT FROM AUTHOR]

We are interested in the structure of the Lcc vertex in the Yang–Mills theory, where c is the ghost field and L the corresponding BRST auxiliary field. This vertex can give us information on other vertices, and the possible conformal structure of the theory should be reflected in the structure of this vertex. There are five two-loop contributions to the Lcc vertex in the Yang–Mills theory. We present here calculation of the first of the five contributions. The calculation has been performed in the position space. One main feature of the result is that it does not depend on any scale, ultraviolet or infrared. The result is expressed in terms of logarithms and Davydychev integral J(1, 1, 1) that are functions of the ratios of the intervals between points of effective fields in the position space. To perform the calculation we apply Gegenbauer polynomial technique and uniqueness method. [ABSTRACT FROM AUTHOR]