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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

A Comprehensive Search for Gamma-Ray Lines in the First Year of Data from the INTEGRAL Spectrometer

Gamma-ray lines are produced in nature by a variety of different physical processes. They can be valuable astrophysical diagnostics providing information the may be unobtainable by other means. We have carried out an extensive search for gamma-ray lines in the first year of public data from the Spectrometer (SPI) on the INTEGRAL mission. INTEGRAL has spent a large fraction of its observing time in the Galactic Plane with particular concentration in the Galactic Center (GC) region (approximately 3 Msec in the first year). Hence the most sensitive search regions are in the Galactic Plane and Center. The phase space of the search spans the energy range 20-8000 keV, and line widths from 0-1000 keV (FWHM) and includes both diffuse and point-like emission. We have searched for variable emission on time scales down to approximately 1000 sec. Diffuse emission has been searched for on a range of different spatial scales from approximately 20 degrees (the approximate field-of-view of the spectrometer) up to the entire Galactic Plane. Our search procedures were verified by the recovery of the known gamma-ray lines at 511 keV and 1809 keV at the appropriate intensities and significances. We find no evidence for any previously unknown gamma-ray lines. The upper limits range from a few x10(exp -5) per square centimeter per second to a few x10(exp -3) per square centimeter per second depending on line width, energy and exposure. Comparison is made between our results and various prior predictions of astrophysical lines

Teegarden, B. J.↗
NASA NTRS1992

Microtopographic evolution of lava flows at Cima volcanic field, Mojave Desert, California

Microtopographic profiles were measured and power spectra calculated for dated lava flow surfaces at Cima volcanic field in the eastern Mojave Desert of California in order to quantify changes in centimeter- to meter-scale roughness as a function of age. For lava flows younger than about 0.8 m.y., roughness over all spatial scales decreases with age, with meter-scale roughness decreasing slightly more than centimeter scales. Flows older than about 0.8 m.y. show a reversal of this trend, becoming as rough as young flows at these scales. Modeling indicates that eolian deposition can explain most of the change observed in the offset, or roughness amplitude, of power spectra of flow surface profiles up to 0.8 m.y. Other processes, such as rubbing and stone pavement development, appear to have a minor effect in this age range. Changes in power spectra of surfaces older than about 0.8 m.y. are consistent with roughening due to fluvial dissection. These results agree qualitatively with a process-response model that attributes systematic changes in flow surface morphology to cyclic changes in the rates of eolian, soil formation, and fluvial processes. Identification of active surficial processes and estimation of the extent of their effects, or stage of surficial evolution, through measurement of surface roughness will help put the correlation of surficial units on a quantitative basis. This may form the basis for the use of radar remote sensing data to help in regional correlations of surficial units.

Farr, Tom G.↗
NASA NTRS2017

Joint Assimilation of SMOS Brightness Temperature and GRACE Terrestrial Water Storage Observations for Improved Soil Moisture Estimation

Observations from recent soil moisture missions (e.g. SMOS) have been used in innovative data assimilation studies to provide global high spatial (i.e. 40 km) and temporal resolution (i.e. 3-days) soil moisture profile estimates from microwave brightness temperature observations. In contrast with microwave-based satellite missions that are only sensitive to near-surface soil moisture (0 - 5 cm), the Gravity Recovery and Climate Experiment (GRACE) mission provides accurate measurements of the entire vertically integrated terrestrial water storage column but, it is characterized by low spatial (i.e. 150,000 km2) and temporal (i.e. monthly) resolutions. Data assimilation studies have shown that GRACE-TWS primarily affects (in absolute terms) deeper moisture storages (i.e., groundwater). This work hypothesizes that unprecedented soil water profile accuracy can be obtained through the joint assimilation of GRACE terrestrial water storage and SMOS brightness temperature observations. A particular challenge of the joint assimilation is the use of the two different types of measurements that are relevant for hydrologic processes representing different temporal and spatial scales. The performance of the joint assimilation strongly depends on the chosen assimilation methods, measurement and model error spatial structures. The optimization of the assimilation technique constitutes a fundamental step toward a multi-variate multi-resolution integrative assimilation system aiming to improve our understanding of the global terrestrial water cycle.

Soil Moisture↗
NASA NTRS2019

Using Power Diagrams to Build Optimal Unstructured Meshes for C-Grid Models

The Model for Prediction Across Scales (MPAS) for Ocean (-O), Sea-Ice (-SI) and Land-Ice (-LI), in addition to the Coastal Ocean Marine Prediction Across Scales (COMPAS) are two novel general circulation models designed to resolve coupled ocean-ice dynamics over variable spatial scales using non-uniform unstructured grids. Both models are based on a conservative mimetic finite-difference/volume formulation (TRiSK), in which staggered momentum, vorticity and mass-based degrees- of-freedom are distributed over an orthogonal 'primal-dual' mesh.

Engwirda, Darren↗
NASA NTRS1994

The rotation of photospheric magnetic fields: A random walk transport model

In an earlier study of solar differential rotation, we showed that the transport of magnetic flux across latitudes acts to establish quasi-stationary patterns, therby accounting for the observed rigid rotation of the large-scale photospheric field. In that paper, the effect of supergranular convection was represented by a continuum diffusion, limiting the applicability of the calculations to large spatial scales. Here we extend the model to scales comparable to that of the supergranulation itself by replacing the diffusive transport with a discrete random walk process. Rotation curves are derived by cross-correlating the simulated photospheric field maps for a variety of time lags and spatial resolutions. When the lag between maps is relatively short less than or approximately = 15 days), the midlatitude correlation functions show two distinct components: a broad feature associated with the large-scale unipolar patterns and a narrow feature originating from small magnetic structures encompossing from one to several supergranular cells. By fitting the broad component we obtain the rigid rotation profile of the patterns, whereas by fitting the narrow component, we recover the differential rate of the photospheric plasma itself. For time lags of 1 month or greater, only the broad feature associated with the long-lived patterns remains clearly identifiable in the simulations.

Wang, Y. -M.↗
NASA NTRS1999

Is It Possible to Distinguish Between Dust and Salt Aerosol Over Waters with Unknown Chlorophyll Concentrations Using Spectral Remote Sensing?

Atmospheric aerosol has uncertain impacts on the global climate system, as well as on atmospheric and bio-geo-chemical processes of regional and local scales. EOS-MODIS is one example of a satellite sensor designed to improve understanding of the aerosols' type, size and distribution at all temporal and spatial scales. Ocean scientists also plan to use data from EOS-MODIS to assess the temporal and spatial coverage of in-water chlorophyll. MODIS is the first sensor planned to observe the combined ocean-atmosphere system with a wide spectral range (from 410 to 2200 nm). Dust aerosol and salt aerosol have similar spectral signals for wavelengths longer than 550 nm, but because dust selectively absorbs blue light, they have divergent signals in the blue wavelength regions (412 to 490 nm). Chlorophyll also selectively absorbs blue radiation, so that varying chlorophyll concentrations produces a highly varying signal in the blue regions, but less variability in the green, and almost no signal in the red to mid-infrared regions. Thus, theoretically, it may be difficult to differentiate dust and salt in the presence of unknown chlorophyll in the ocean. This study attempts to address the cases in which aerosol and chlorophyll signals can and cannot be separated. For the aerosol spectra, we use the aerosol lookup table from the operational MODIS aerosol-over-ocean algorithm, and for chlorophyll spectra, we use the SeaBAM data set (created for SeaWiFS). We compare the signals using Principal Component Analysis and attempt to retrieve both chlorophyll and aerosol properties using a variant of the operational MODIS aerosol-over-ocean algorithm. Results show that for small optical depths, less than 0.5, it is not possible to differentiate between dust and salt and to determine the chlorophyll concentration at the same time. For larger aerosol optical depths, the chlorophyll signals are comparatively insignificant, and we can hope to distinguish between dust and salt.

Levy, R. C.↗
NASA NTRS1994

A spectral formalism for computing three-dimensional deformations due to surface loads. 1: Theory

We outline a complete spectral formalism for computing high spatial resolution three-dimensional deformations arising from the surface mass loading of a spherically symmetric planet. The main advantages of the formalism are that all surface mass loads are always described using a consistent mathematical representation and that calculations of deformation fields for various spatial resolutions can be performed by simpley altering the spherical harmonic degree truncation level of the procedure. The latter may be important when incorporating improved observational constraints on a particular surface mass load, when considering potential errors in the computed field associated with mass loading having a spatial scale unresolved by the observational constraints, or when treating a number of global surface mass loads constrained with different spatial resolutions. The advantages do not extend to traditional 'Green's function' approaches which involve surface element discretizations of the global mass loads. Another advantage of the spectral formalism, over the Green's function approach, is that a posteriori analyses of the computed deformation fields are easily performed. In developing the spectral formalism, we consider specific cases where the Earth's mantle is assumed to respond as an elastic, slightly anelastic, or linear viscoelastic medium. In the case of an elastic or slightly anelastic mantle rheology the spectral response equations incorporate frequency dependent Love numbers. The formalism can therefore be used, for example, to compute the potentially resonant deformational response associated with the free core nutation and Chandler wobble eigenfunctions. For completeness, the spectral response equations include both body forces, as arise from the gravitational attraction of the Sun and the Moon, and surface mass loads. In either case, and for both elastic and anelastic mantle rheologies, we outline a pseudo-spectral technique for computing the ocean adjustment associated with the total gravitational perturbation induced by the external forcing. Three-dimensional deformations computed using the usual Love number approach are generally referenced to an origin at the center of mass of the undeformed planet. We derive a spectral technique for transforming the results to an origin located at the center of mass of the deformed planet.

Mitrovica, J. X.↗
NASA NTRS1998

A2111: A z= 0.23 Butcher-Oemler Cluster with a Non-Isothermal Atmosphere and Normal Metallicity

We report results from an x-ray spectral study of the z=0.23 Abell 2111 galaxy cluster using the Advanced Satellite for Astrophysics and Cosmology and the ROSAT Position Sensitive Proportional Counter. By correcting for the energy-dependent point-spread function of the instruments, we have examined the temperature structure of the cluster. The cluster's core within 3 is found to have a temperature of 5.4 +/- 0.5 keV, significantly higher than 2.8 +/-0.7 keV in the surrounding region of r = 3-6. This radially decreasing temperature structure can be parameterized by a polytropic index of gamma less than 1.4. Furthermore, the intracluster medium appears clumpy on scales less than 1. Early studies have revealed that the x-ray centroid of the cluster shifts with spatial scale and the overall optical and x-ray morphology is strongly elongated. These results together suggest that A2111 in undergoing a merger, which is likely responsible for the high fraction of blue galaxies observed in the cluster. We have further measured the abundance of the medium as 0.25 +/- 0.14 solar. This value is similar to those of nearby clusters which do not show a large blue galaxy function, suggesting that star formation in disk galaxies and subsequent loss to the intracluster medium do not drastically alter the average abundance of a cluster since z=0.23.

Wang, Q. Daniel↗
NASA NTRS1999

Its a Wind, Its a Wave, Its Two Phenomena in One: Jerry Schubert, Superrotation, and the UV Markings on Venus

In the early 1970's, ground-based astronomers had already discovered that Ultraviolet (UV) cloud markings on Venus reappeared every 4 days. When radar evidence later revealed a 243-day rotation period for the solid planet, planetary scientists were faced with a quandary: Could the Venus atmosphere really move 60 times as fast as the planet below, or were the apparent movements of the UV features just an illusion caused by propagating waves? The former explanation seemed unlikely - a planet that hardly rotates should generate only a very sluggish circulation. The historical impact of Jerry Schubert's moving flame theory was twofold: It was the forerunner of current thermal tide explanations of the cloud-level superrotation, but it was also the first plausible mechanism for explaining a seemingly inconsistent set of observations. In 1974, Mariner 10 acquired UV images of the Venus clouds at unprecedented levels of detail. Although few have noted it, this began the shift of planetary atmospheric research primarily from the domain of astronomy to that of meteorology. Jerry was among the first scientists to apply terrestrial meteorology to the analysis of planetary data. At that time a young UCLA graduate student with plans to do research on mantle convection, but having flunked the solid earth geophysics section of his departmental comprehensive exam, was gently invited by Jerry to switch to atmospheric science. Jerry suggested that the Venus UV features could be revealing both superrotating winds and planetary-scale waves at the same time, and that we could distinguish the two by looking at motions on different spatial scales. This was my first science research lesson - the complexity of real geophysical systems. Over the next couple of years I was inculcated with Jerry's philosophy of a comprehensive, rigorous approach to research, which manifested itself as a scouring of the literature and the UCLA meteorology faculty to learn about every possible type of planetary-scale wave. The resulting identification of large-scale UV features on Venus as the product of Kelvin and Rossby-type wave motions was validated by extensive Pioneer Venus observations a decade later and remains one of the best examples of the use of terrestrial knowledge to understand other planets.

DelGenio, Anthony↗
NASA NTRS1999

Atmospheric Dynamics of Venus: Scales Large and Small

Over the past 30 years, Gerald Schubert has made significant contributions to the understanding of Venus atmospheric dynamics. His research of Venus' atmosphere spans spatial scales both large and small, including: Venus westward atmospheric superrotation, Planetary scale waves and the global "Y" ultraviolet feature, Wind streaks and the global circulation of the lower atmosphere, Mesoscale convection in the clouds of Venus, Vertical propagation of small-scale internal gravity waves, and Interaction between small-scale dynamics and the large-scale mean flow. Furthermore, his role as Principal Investigator of the Pioneer Venus Working Group on Structure and Circulation in the late 1970's and early 1980's was instrumental in the advancement of our understanding of Venus' atmosphere. The Pioneer Venus work serves as the cornerstone of our view of Venus atmospheric dynamics today. This paper will review Jerry's extensive research on Venus' atmosphere. In addition, recent results on convectively generated internal gravity waves will be presented that combine his lifelong, interest in both large-scale and small-scale dynamics. It will be shown that small-scale internal gravity waves generated by convection within the clouds of Venus decelerate the westward superrotation below the clouds. Thus, mechanisms that support the Venus westward superrotation must overcome the influence of small-scale dynamics in the lower atmosphere.

Baker, R. David↗
NASA NTRS2002

SOHO/CDS Measurements of Coronal EUV Polarization above the Limb

Attempts to measure polarization in coronal extreme ultraviolet (EUV) emission above the solar limb have been made using the SOHO/CDS normal-incidence spectrometer which has a polarization sensitivity of about 50%, a property that causes variations in intensity response as a function of the spacecraft's roll angle for polarized light. Such observations were made on the disk and up to 0.22 solar radii above the solar limb in a number of EUV lines during two special roll-maneuvers of the SOHO spacecraft. Measurements of intensity gradients were made above a modestly active equatorial region in 1997 and above a relatively cool polar region in 2001. Observed emission lines include He I 584 A, He II 304 A, O IV 555+610 A, O V 630 A, Mg IX 368 A, Mg X 610+625 A, and Si XI 303 A, formed at temperatures that evenly cover the range in log T from 4.1 to 6.2. Near the disk, measured intensities of all lines fall off exponentially at different rates that can be used to determine the density scale-heights of the emitting plasma, since this emission is dominated by collisional excitation with an Ne-squared dependence. Assuming hydrostatic equilibrium, the intensity gradient for each line can then be converted into a 'scale-height temperature', which is found to be closely related to the ionization temperature of each line over the wide range of lines and solar conditions observed. Thus the large-scale corona is remarkably uniform, even though clearly displaying a great deal of structure and non-uniformity on smaller spatial scales. Beyond a certain distance, intensity gradients of the cooler lines switch over to a flatter exponential slope, suggesting that this radiation is dominated by resonance scattering which varies as Ne to the first power. Such radiation should also be linearly polarized in the plane containing the line-of-sight and the solar center, a signature that would strongly confirm this interpretation.

Thomas, Roger J.↗
NASA NTRS2022

Using Atmospheric Trace Gas Vertical Profiles to Evaluate Model Fluxes: A Case Study of Arctic-Cap Observations and Geos Simulations for the ABoVE Domain

Accurate estimates of carbon–climate feedbacks require an independent means for evaluating surface flux models at regional scales. The altitude-integrated enhancement (AIE) derived from the Arctic Carbon Atmospheric Profiles (Arctic-CAP) project demonstrates the utility of this bulk quantity for surface flux model evaluation. This bulk quantity leverages background mole fraction values from the middle free troposphere, is agnostic to uncertainties in boundary layer height, and can be derived from model estimates of mole fractions and vertical gradients. To demonstrate the utility of the bulk quantity, six airborne profiling surveys of atmospheric carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) throughout Alaska and northwestern Canada between April and November 2017 were completed as part of NASA’s Arctic–Boreal Vulnerability Experiment (ABoVE). The Arctic-CAP sampling strategy involved acquiring vertical profiles of CO2, CH4, and CO from the surface to 5 km altitude at 25 sites around the ABoVE domain on a 4- to 6-week time interval. All Arctic-CAP measurements were compared to a global simulation using the Goddard Earth Observing System (GEOS) modeling system. Comparisons of the AIE bulk quantity from aircraft observations and GEOS simulations of atmospheric CO2, CH4, and CO highlight the fidelity of the modeled surface fluxes. The model–data comparison over the ABoVE domain reveals that while current state-of-the-art models and flux estimates are able to capture broad-scale spatial and temporal patterns in near-surface CO2 and CH4 concentrations, more work is needed to resolve fine-scale flux features that are captured in CO observations

CO2↗
NASA NTRS1978

Coronal hole evolution by sudden large scale changes

Sudden shifts in coronal-hole boundaries observed by the S-054 X-ray telescope on Skylab between May and November, 1973, within 1 day of CMP of the holes, at latitudes not exceeding 40 deg, are compared with the long-term evolution of coronal-hole area. It is found that large-scale shifts in boundary locations can account for most if not all of the evolution of coronal holes. The temporal and spatial scales of these large-scale changes imply that they are the results of a physical process occurring in the corona. It is concluded that coronal holes evolve by magnetic-field lines' opening when the holes are growing, and by fields' closing as the holes shrink.

Nolte, J. T.↗
NASA NTRS1989

A small-scale plasmoid formed during the May 13, 1985, AMPTE magnetotail barium release

Plasmoids are closed magnetic-loop structures with entrained hot plasma which are inferred to occur on large spatial scales in space plasma systems. A model is proposed here to explain the brightening and rapid tailward movement of the barium cloud released by the AMPTE IRM spacecraft on May 13, 1985. The model suggests that a small-scale plasmoid was formed due to a predicted development of heavy-ion-induced tearing in the thinned near-tail plasma sheet. Thus, a plasmoid may actually have been imaged due to the emissions of the entrained plasma ions within the plasma bubble.

Baker, D. N.↗
NASA NTRS1998

Equatorial Density Irregularity Structures at Intermediate Scales and Their Temporal Evolution

We examine high resolution measurements of ion density in the equatorial ionosphere from the AE-E satellite during the years 1977-1981. Structure over spatial scales from 18 km to 200 m is characterized by the spectrum of irregularities at larger and smaller scales and at altitudes above 350 km and below 300 km. In the low-altitude region, only small amplitude large-scale (lambda greater than 5 km) density modulations are often observed, and thus the power spectrum of these density structures exhibits a steep spectral slope at kilometer scales. In the high-altitude region, sinusoidal density fluctuations, characterized by enhanced power near 1-km scale, are frequently observed during 2000-0200 LT. However, such fluctuations are confined to regions at the edges of larger bubble structures where the average background density is high. Small amplitude irregularity structures, observed at early local time hours, grow rapidly to high-intensity structures in about 90 min. Fully developed structures, which are observed at late local time hours, decay very slowly producing only-small differences in spectral characteristics even 4 hours later. The local time evolution of irregularity structure is investigated by using average statistics for low-(1% less than sigma less than 5%) and high-intensity (sigma greater than 10%) structures. At lower altitudes, little chance in the spectral slope is seen as a function of local time, while at higher attitudes the growth and maintenance of structures near 1 km scales dramatically affects the spectral slope.

Kil, Hyosub↗
NASA NTRS1999

Low-Frequency Oscillations and Transport Processes Induced by Multiscale Transverse Structures in the Polar Wind Outflow: A Three-Dimensional Simulation

Multiscale transverse structures in the magnetic-field-aligned flows have been frequently observed in the auroral region by FAST and Freja satellites. A number of multiscale processes, such as broadband low-frequency oscillations and various cross-field transport effects are well correlated with these structures. To study these effects, we have used our three-dimensional multifluid model with multiscale transverse inhomogeneities in the initial velocity profile. Self-consistent-frequency mode driven by local transverse gradients in the generation of the low field-aligned ion flow and associated transport processes were simulated. Effects of particle interaction with the self-consistent time-dependent three-dimensional wave potential have been modeled using a distribution of test particles. For typical polar wind conditions it has been found that even large-scale (approximately 50 - 100 km) transverse inhomogeneities in the flow can generate low-frequency oscillations that lead to significant flow modifications, cross-field particle diffusion, and other transport effects. It has also been shown that even small-amplitude (approximately 10 - 20%) short-scale (approximately 10 km) modulations of the original large-scale flow profile significantly increases low-frequency mode generation and associated cross-field transport, not only at the local spatial scales imposed by the modulations but also on global scales. Note that this wave-induced cross-field transport is not included in any of the global numerical models of the ionosphere, ionosphere-thermosphere, or ionosphere-polar wind. The simulation results indicate that the wave-induced cross-field transport not only affects the ion outflow rates but also leads to a significant broadening of particle phase-space distribution and transverse particle diffusion.

Ganguli, Supriya B.↗
NASA NTRS2021

Automated Uas Measurements of Reflectance and Solar Induced Florescence (SIF) for Assessment Of the Dinamics in Photosynthetic Function, Application for Maze (Zea Mays L.) in Greenbelt, Maryland, Us

For accurate assessment of vegetation function there is a strong need for advancement in the remote sensing methods and instruments, to enable monitoring of the parameters governing photosynthesis at the temporal frequency relevant to their dynamics and at a spatial scale that allows practical assessment and management. Currently, no single sensor can provide data at the desired high temporal, spectral and spatial resolutions. Our field measurements obtained using the integrated UAS Piccolo system during the summers of2017 and 2018 demonstrate that science quality reflectance and solar induced fluorescence (SIF) data can be retrieved with high temporal frequency using small Unmanned Aerial Systems (UAS). The implemented approach facilitates data comparisons through space and time, and the integration with other spectral satellite and airborne data. This investigation contributes for bridging the gap in Earth observation between field and airborne measurements by implementing autonomous methods for obtaining high temporal frequency spectroscopy measurements from an Unmanned Aerial Systems (UAS) at various illumination conditions. An advancement in the Intelligent Payload Module (IPM) facilitated the implementation of an optimization workflow to collect spectral data for characterizing vegetation reflectance and solar induced fluorescence (SIF).

Petya Campbell↗
NASA NTRS2013

Mapping Impervious Surfaces Globally at 30m Resolution Using Global Land Survey Data

Impervious surfaces, mainly artificial structures and roads, cover less than 1% of the world's land surface (1.3% over USA). Regardless of the relatively small coverage, impervious surfaces have a significant impact on the environment. They are the main source of the urban heat island effect, and affect not only the energy balance, but also hydrology and carbon cycling, and both land and aquatic ecosystem services. In the last several decades, the pace of converting natural land surface to impervious surfaces has increased. Quantitatively monitoring the growth of impervious surface expansion and associated urbanization has become a priority topic across both the physical and social sciences. The recent availability of consistent, global scale data sets at 30m resolution such as the Global Land Survey from the Landsat satellites provides an unprecedented opportunity to map global impervious cover and urbanization at this resolution for the first time, with unprecedented detail and accuracy. Moreover, the spatial resolution of Landsat is absolutely essential to accurately resolve urban targets such a buildings, roads and parking lots. With long term GLS data now available for the 1975, 1990, 2000, 2005 and 2010 time periods, the land cover/use changes due to urbanization can now be quantified at this spatial scale as well. In the Global Land Survey - Imperviousness Mapping Project (GLS-IMP), we are producing the first global 30 m spatial resolution impervious cover data set. We have processed the GLS 2010 data set to surface reflectance (8500+ TM and ETM+ scenes) and are using a supervised classification method using a regression tree to produce continental scale impervious cover data sets. A very large set of accurate training samples is the key to the supervised classifications and is being derived through the interpretation of high spatial resolution (approx. 2 m or less) commercial satellite data (Quickbird and Worldview2) available to us through the unclassified archive of the National Geospatial Intelligence Agency (NGA). For each continental area several million training pixels are derived by analysts using image segmentation algorithms and tools and then aggregated to the 30m resolution of Landsat. Here we will discuss the production/testing of this massive data set for Europe, North and South America and Africa, including assessments of the 2010 surface reflectance data. This type of analysis is only possible because of the availability of long term 30m data sets from GLS and shows much promise for integration of Landsat 8 data in the future.

global land survey↗