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Sample records for radiometric dating techniques

  1. Radiometric Dating Does Work!

    ERIC Educational Resources Information Center

    Dalrymple, G. Brent

    2000-01-01

    Discusses the accuracy of dating methods and creationist arguments that radiometric dating does not work. Explains the Manson meteorite impact and the Pierre shale, the ages of meteorites, the K-T tektites, and dating the Mount Vesuvius eruption. (Author/YDS)

  2. Radiometric Dating in Geology.

    ERIC Educational Resources Information Center

    Pankhurst, R. J.

    1980-01-01

    Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)

  3. Use of radiometric (Cs-137, Pb-210), geomorphic, and stratigraphic techniques to date recent oxbow sediments in the Rio Puerco drainage Grants uranium region, New Mexico

    SciTech Connect

    Popp, C.J.; Dehn, M. ); Hawley, J.W.; Love, D.W. )

    1988-06-01

    In the absence of historic geochemical baseline data for the Grants uranium region, environmental changes resulting from uranium mine-mill activities can be determined only by indirect methods. A methodology for determining the age of recent sediments in streams draining the region has been established based on combined geomorphic, stratigraphic, and radiometric dating techniques. Because clay-rich sediments retain possible radionuclides and heavy metals derived from mineralization and mined sources, sample sites which contain fine-grained deposits that both predate and postdate mine-mill activity were located in abandoned-channel segments (oxbows) of major streams draining the eastern Grants uranium region. Aerial photographs (and derivative maps) taken between 1935 and 1971 provided the historical and geomorphic documentation of approximate dates of oxbow formation and ages of alluvial fills in the abandoned-channel segments. Pits were dug at these oxbow sites to determine stratigraphy and composition of the deposits. Samples collected from pit walls and auger holes below the pits were subjected to radiometric analysis by gamma ray spectrometry for the artificial radionuclide Cs-137 and the natural radionuclide Pb-210 as well as other U-238 and Th-232 daughters. Because of the dynamic nature of the system, absolute dating with Cs-137 was not possible but samples could be dated as either pre- or post-1950. The 1950 date is important because it marked the beginning of the uranium exploitation in the region. The Pb-210 dating was not possible because background Pb-210 was very high relative to fallout Pb-210.

  4. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica

    PubMed Central

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V.; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P.; Brook, Edward J.

    2014-01-01

    We present successful 81Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The 81Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) 85Kr and 39Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the 81Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130–115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA 81Kr analysis requires a 40–80-kg ice sample; as sample requirements continue to decrease, 81Kr dating of ice cores is a future possibility. PMID:24753606

  5. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica.

    PubMed

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P; Brook, Edward J

    2014-05-13

    We present successful (81)Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The (81)Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) (85)Kr and (39)Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the (81)Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130-115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA (81)Kr analysis requires a 40-80-kg ice sample; as sample requirements continue to decrease, (81)Kr dating of ice cores is a future possibility. PMID:24753606

  6. Radiometric Techniques for Emissivity and Temperature Measurements for Industrial Applications

    NASA Astrophysics Data System (ADS)

    Vuelban, E. M.; Girard, F.; Battuello, M.; Neme?ek, P.; Maniur, M.; Pavlsek, P.; Paans, T.

    2015-07-01

    Radiometric techniques for temperature measurements are indispensable in industrial applications, particularly when the use of contact thermometers is hard or impossible to realize. The principles and realizations of some new and extended radiometric techniques for measuring the emissivity and temperature of an object are presented. Using the described techniques, the emissivity and temperature of an Inconel 600 sample at high temperatures in laboratory conditions were determined. The validation of the temperature measurement of the same sample in a simulated industrial condition is also presented.

  7. In situ radiometric dating on Mars: Investigation of the feasibility of K-Ar dating using flight-type mass and X-ray spectrometers

    NASA Astrophysics Data System (ADS)

    Talboys, D. L.; Barber, S.; Bridges, J. C.; Kelley, S. P.; Pullan, D.; Verchovsky, A. B.; Butcher, G.; Fazel, A.; Fraser, G. W.; Pillinger, C. T.; Sims, M. R.; Wright, I. P.

    2009-09-01

    The absolute chronology of Mars is poorly known and, as a consequence, a key science aim is to perform accurate radiometric dating of martian geological materials. The scientific benefits of in situ radiometric dating are significant and arguably of most importance is the calibration of the martian cratering rate, similar to what has been achieved for the Moon, to reduce the large uncertainties on absolute boundary ages of martian epochs. The Beagle 2 Mars lander was capable of performing radiometric date measurements of rocks using the analyses from two instruments in its payload: (i) the X-ray Spectrometer (XRS) and (ii) the Gas Analysis Package (GAP). We have investigated the feasibility of in situ radiometric dating using the K-Ar technique employing flight-like versions of Beagle 2 instrumentation. The K-Ar ages of six terrestrial basalts were measured and compared to the 'control' Ar-Ar radiometric ages in the range 171-1141 Ma. The K content of each basalt was measured by the flight spare XRS and the 40Ar content using a laboratory analogue of the GAP. The K-Ar ages of five basalts broadly agreed with their corresponding Ar-Ar ages. For one final basalt, the 40Ar content was below the detection limit and so an age could not be derived. The precision of the K-Ar ages was 30% on average. The conclusions from this study are that careful attention must be paid to improving the analytical performance of the instruments, in particular the accuracy and detection limits. The accuracy of the K and Ar measurements are the biggest source of uncertainty in the derived K-Ar age. Having investigated the technique using flight-type planetary instrumentation, we conclude that come of the principle challenges of conducting accurate in situ radiometric dating on Mars using instruments of these types include determining the sample mass, ensuring all the argon is liberated from the sample given the maximum achievable temperature of the mass spectrometer ovens, and argon loss and non-radiogenic argon in the analysed samples.

  8. Radiometric dating of sediments using fission tracks in conodonts

    USGS Publications Warehouse

    Sachs, H.M.; Denkinger, M.; Bennett, C.L.; Harris, A.G.

    1980-01-01

    Conodonts are microfossils which are commonly found in marine rocks of Cambrian to Triassic age. Although their biological affinities are difficult to assess, conodonts are valuable stratigraphical indices for much of their geological range1. Recent work has also established that conodont colour alteration indices (CAI) are useful guides to diagenetic temperatures and hence burial depth2. Fission tracks3 in conodonts allow measurement of uranium concentrations and estimates of 'age' to be made using isotopic methods4. We report here that fission tracks counted in irradiated, thermally unaltered (as indicated by CAI) middle Palaeozoic conodonts indicate typical uranium concentrations of ???1 part in 10 9, with some samples higher. A single specimen of Siphonodella from the Lower Mississippian yielded an age estimate of 380??140 Myr consistent with conventional interpolations. This method may also allow the unroofing of deeply buried sediments to be dated. ?? 1980 Nature Publishing Group.

  9. Calibrating Late Quaternary terrestrial climate signals: radiometrically dated pollen evidence from the southern Sierra Nevada, USA

    USGS Publications Warehouse

    Litwin, Ronald J.; Smoot, Joseph P.; Durika, Nancy J.; Smith, George I.

    1999-01-01

    We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000 yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes - one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Searles Lake) served as a reference section for improving the effective radiometric age control in a nearby and more complete pollen record (Owens Lake) because they: (1) are situated ~90 km apart in the same drainage system (on, and immediately leeward of, the eastern flank of the Sierra Nevada), and (2) preserved strikingly similar pollen profiles and concordant sequences of sedimentological changes. Pollen assemblages from both lakes are well preserved and diverse, and document serial changes in Late Pleistocene and Holocene plant zone distribution and composition in the westernmost Great Basin; they consist of taxa now inhabiting montane forest, woodland, steppe, and desert-scrub environments. The studied core intervals are interpreted here to be the terrestrial equivalent of marine ?18O stages 1 through 9; these pollen profiles now appear to be among the best radiometrically dated Late Pleistocene records of terrestrial climate change known.

  10. Antiquity of man in America indicated by radiometric dates on the Yuha burial site

    USGS Publications Warehouse

    Bischoff, J.L.; Merriam, R.; Childers, W.M.; Protsch, R.

    1976-01-01

    MUCH evidence suggests that man was present in the Western Hemisphere before 12,000 yr ago, but the case has remained less than conclusive 1. In some situations, the geological age of the site is reasonably well established but the association or nature of the artefacts is questionable2,3. In other cases, museum specimens of human bones dated by radiocarbon analysis of collagen lack desirable information concerning site location, geology, and stratigraphy even though the accuracy of their absolute ages seems valid4-6. We report here the results of radiometric dates of the Yuha burial site from Imperial County, California, for which the geology and stratigraphy have been documented and reported in detail7. ?? 1976 Nature Publishing Group.

  11. Radiometric Calibration Techniques for Signal-of-Opportunity Reflectometers

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Shah, Rashmi; Deshpande, Manohar; Johnson, Carey

    2014-01-01

    Bi-static reflection measurements utilizing global navigation satellite service (GNSS) or other signals of opportunity (SoOp) can be used to sense ocean and terrestrial surface properties. End-to-end calibration of GNSS-R has been performed using well-characterized reflection surface (e.g., water), direct path antenna, and receiver gain characterization. We propose an augmented approach using on-board receiver electronics for radiometric calibration of SoOp reflectometers utilizing direct and reflected signal receiving antennas. The method calibrates receiver and correlator gains and offsets utilizing a reference switch and common noise source. On-board electronic calibration sources, such as reference switches, noise diodes and loop-back circuits, have shown great utility in stabilizing total power and correlation microwave radiometer and scatterometer receiver electronics in L-band spaceborne instruments. Application to SoOp instruments is likely to bring several benefits. For example, application to provide short and long time scale calibration stability of the direct path channel, especially in low signal-to-noise ratio configurations, is directly analogous to the microwave radiometer problem. The direct path channel is analogous to the loopback path in a scatterometer to provide a reference of the transmitted power, although the receiver is independent from the reflected path channel. Thus, a common noise source can be used to measure the gain ratio of the two paths. Using these techniques long-term (days to weeks) calibration stability of spaceborne L-band scatterometer and radiometer has been achieved better than 0.1. Similar long-term stability would likely be needed for a spaceborne reflectometer mission to measure terrestrial properties such as soil moisture.

  12. The Relationship between Balancing Reactions and Reaction Lifetimes: A Consideration of the Potassium-Argon Radiometric Method for Dating Minerals

    ERIC Educational Resources Information Center

    Howard, William A.

    2005-01-01

    A detailed examination of a commonly accepted practice in geology offers an example of how to stimulate critical thinking, teaches students how to read reactions, and challenges students to formulate better experiments for determining mineral ages more accurately. A demonstration of a Potassium-Argon radiometric method for dating minerals is…

  13. The Relationship between Balancing Reactions and Reaction Lifetimes: A Consideration of the Potassium-Argon Radiometric Method for Dating Minerals

    ERIC Educational Resources Information Center

    Howard, William A.

    2005-01-01

    A detailed examination of a commonly accepted practice in geology offers an example of how to stimulate critical thinking, teaches students how to read reactions, and challenges students to formulate better experiments for determining mineral ages more accurately. A demonstration of a Potassium-Argon radiometric method for dating minerals is

  14. 14C-AMS at the Leibniz-Labor: radiometric dating and isotope research

    NASA Astrophysics Data System (ADS)

    Grootes, Pieter M.; Nadeau, Marie-Jose; Rieck, Anke

    2004-08-01

    The Leibniz-Labor was founded to provide radiometric dating services using AMS and measured over 15 000 samples and 26 800 targets up to September 2002. Research and development have primarily been directed at improving the efficiency and reliability of AMS measurements, optimising existing sample preparation procedures for AMS and developing new ones. The standard chemical pre-treatment of organic radiocarbon samples produces often two fractions: one from which contaminants have been removed, and one in which they have been enriched. Dating both fractions reveals the degree of sample contamination. This provides a useful indication of the reliability of the sample age obtained and of the environmental conditions where the sample was taken. Upgrades to reduce maintenance include replacing four cryo- by turbo pumps, installing a deionizer loop, which keeps conductivity between 100 and 150 ?S/cm to control corrosion, in the closed cooling water circuit, and developing a new sample wheel, which holds target holders with a groove and spring clip. Long term stability is demonstrated by the results obtained for IAEA reference materials, measured routinely and regularly over the years. Tests made as part of the FIRI project demonstrate that reliable measurements down to <0.1 mg C can be made.

  15. Dating Techniques in Archaeology and Paleoanthropology.

    ERIC Educational Resources Information Center

    Taylor, R. E.

    1987-01-01

    Discusses some of the new physical dating methods being used by archaeologists and paleoanthropologists to study the material remains of ancient primates. Describes the quaternary physical dating techniques, advances in radiocarbon dating, and the radiocalcium data method. (TW)

  16. Dating techniques in archaeology and paleoanthropology

    SciTech Connect

    Taylor, R.E.

    1987-02-15

    Archaeologists have an increasing array of physical dating methods at their disposal. R.E. Taylor of the University of California discusses available techniques, recent advances in radiocarbon dating, and current developments in radiocalcium dating.

  17. Radiometric dating of Ochoan (Permian) evaporites, WIPP (Waste Isolation Pilot Plant) site, Delaware Basin, New Mexico, USA

    SciTech Connect

    Brookins, D.G.; Lambert, S.J.

    1986-01-01

    We have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facilty) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization; (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data; and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 +- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of *40-Ar. K-Ar dates on leonites and kieserities are also low due to *40-Ar loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.

  18. Artifact correction and absolute radiometric calibration techniques employed in the Landsat 7 image assessment system

    USGS Publications Warehouse

    Boncyk, Wayne C.; Markham, Brian L.; Barker, John L.; Helder, Dennis

    1996-01-01

    The Landsat-7 Image Assessment System (IAS), part of the Landsat-7 Ground System, will calibrate and evaluate the radiometric and geometric performance of the Enhanced Thematic Mapper Plus (ETM +) instrument. The IAS incorporates new instrument radiometric artifact correction and absolute radiometric calibration techniques which overcome some limitations to calibration accuracy inherent in historical calibration methods. Knowledge of ETM + instrument characteristics gleaned from analysis of archival Thematic Mapper in-flight data and from ETM + prelaunch tests allow the determination and quantification of the sources of instrument artifacts. This a priori knowledge will be utilized in IAS algorithms designed to minimize the effects of the noise sources before calibration, in both ETM + image and calibration data.

  19. Radiometric dating of the type-site for Homo heidelbergensis at Mauer, Germany

    PubMed Central

    Wagner, Gnther A.; Krbetschek, Matthias; Degering, Detlev; Bahain, Jean-Jacques; Shao, Qingfeng; Falgures, Christophe; Voinchet, Pierre; Dolo, Jean-Michel; Garcia, Tristan; Rightmire, G. Philip

    2010-01-01

    The Mauer mandible, holotype of Homo heidelbergensis, was found in 1907 in fluvial sands deposited by the Neckar River 10 km southeast of Heidelberg, Germany. The fossil is an important key to understanding early human occupation of Europe north of the Alps. Given the associated mammal fauna and the geological context, the find layer has been placed in the early Middle Pleistocene, but confirmatory chronometric evidence has hitherto been missing. Here we show that two independent techniques, the combined electron spin resonance/U-series method used with mammal teeth and infrared radiofluorescence applied to sand grains, date the type-site of Homo heidelbergensis at Mauer to 609 40 ka. This result demonstrates that the mandible is the oldest hominin fossil reported to date from central and northern Europe and raises questions concerning the phyletic relationship of Homo heidelbergensis to more ancient populations documented from southern Europe and in Africa. We address the paleoanthropological significance of the Mauer jaw in light of this dating evidence. PMID:21041630

  20. Radiometric dating of the Earlier Stone Age sequence in excavation I at Wonderwerk Cave, South Africa: preliminary results.

    PubMed

    Chazan, Michael; Ron, Hagai; Matmon, Ari; Porat, Naomi; Goldberg, Paul; Yates, Royden; Avery, Margaret; Sumner, Alexandra; Horwitz, Liora Kolska

    2008-07-01

    We present here the results of 44 paleomagnetic measurements, and single cosmogenic burial and optically stimulated luminescence ages for the Earlier Stone Age deposits from Wonderwerk Cave, Northern Cape, South Africa. The resulting paleomagnetic sequence: N>R>N>R>N constrains the Earlier Stone Age strata in this part of the site to between approximately 0.78-1.96 Ma. A single cosmogenic date of approximately 2.0 Ma from the base of the section offers some corroboration for the paleomagnetic sequence. Preliminary results indicate that the small lithic assemblage from the basal stratum may contain an Oldowan facies. This is overlain by several strata containing Acheulean industries. The preliminary radiometric dates reported here place the onset of the Acheulean at this site to approximately 1.6 Ma, which is roughly contemporaneous with that of East Africa. PMID:18501953

  1. A Comprehensive Paleomagnetic Study on Radiometrically Dated Late Cretaceous Lava Flows from Jalisco Block (Western Mexico)

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Cervantes, M. A.; Gogichaishvili, A.; Morales, J.

    2014-12-01

    Western and central Mexico is segmented by several regional structural systems that bound crustal blocs. Paleomagnetic data from the western and eastern Trans Mexican Volcanic Belt as well as from adjacent terrains are still scarce which limits analyses of the both local and regional-scale tectonic evolution. A combined radiometric and paleomagnetic survey performed on late Cretaceous lava flows demonstrate that vertical-axis rotations characterize the paleotectonic evolution of western-central Mexico. The characteristic paleomagnetic directions determined in this study may be considered of primary (thermoremanent) origin. Multicomponent demagnetization plots were observed in some cases. In general, the polarity obtained for the flows studied is consistent with their stratigraphic position and with the radiometric age determination. The mean inclination is in reasonably good agreement with the expected inclination for the Late Creataceous, as derived from reference poles given by Besse and Courtillot (2002) for the North American craton. The declination, however, is quite different from that expected, which suggests a possible counterclockwise tectonic rotation of at least 12. Aceptable palointensity determinations were obtained for only eleven individual samples from two basaltic lava flows. The mean virtual dipole moment (VDM) obtained in this study is 4.2 1.2 _ 1022 A m2, which is almost half than the present geomagnetic field strength.

  2. Direct radiometric dating of hydrocarbon deposits using rhenium-osmium isotopes.

    PubMed

    Selby, David; Creaser, Robert A

    2005-05-27

    Rhenium-osmium (Re-Os) data from migrated hydrocarbons establish the timing of petroleum emplacement for the giant oil sand deposits of Alberta, Canada, at 112 +/- 5.3 million years ago. This date does not support models that invoke oil generation and migration for these deposits in the Late Cretaceous. Most Re-Os data from a variety of deposits within the giant hydrocarbon system show similar characteristics, supporting the notion of a single source for these hydrocarbons. The Re-Os data disqualify Cretaceous rocks as the primary hydrocarbon source but suggest an origin from older source rocks. This approach should be applicable to dating oil deposits worldwide. PMID:15919988

  3. Radiometric dating of quaternary deposits and the hominid mandible of lake banyolas, Spain

    USGS Publications Warehouse

    Julia, R.; Bischoff, J.L.

    1991-01-01

    We report results of U-series analyses of the travertine matrix surrounding the Banyolas mandible that indicate an age of 45??4 ka bp. The mandible, an archaic hominid fossil generally deemed of mid-Pleistocene age, was recovered from a travertine matrix in 1887. Similar analyses on 21 travertine samples from quarries near the discovery site yield coherent U-series dates in correct stratigraphic order, ranging from 44 ka bp to 117 ka bp. Isotopic composition of these samples and the mandible matrix show no evidence of open system behaviour. Coherent isotopic results from adjacent quarries support the validity of the date on the mandible travertine, and we conclude the mandible is much younger than previously believed. ?? 1991.

  4. Potential drug targets for Mycobacterium avium defined by radiometric drug-inhibitor combination techniques.

    PubMed Central

    Rastogi, N; Goh, K S; Wright, E L; Barrow, W W

    1994-01-01

    Previously established radiometric techniques were used to assess the effectiveness of combined antimicrobial drug-inhibitory drug (drug-inhibitor) treatment on two clinical isolates of the Mycobacterium avium complex representing three colony variants: smooth opaque (dome) (SmO), smooth transparent (SmT), and rough (Rg). All variants were identified as members of the M. avium complex; however, only the SmT colony type of strain 373 possessed characteristic serovar-specific glycopeptidolipid (GPL) antigens. MICs, determined radiometrically, of drugs with the potential to inhibit the biosynthesis of GPL antigens or other cell envelope constituents were similar for all strains. These drugs included cerulenin, N-carbamyl-DL-phenylalanine, N-carbamyl-L-isoleucine, trans-cinnamic acid, ethambutol, 1-fluoro-1-deoxy-beta-D-glucose, 2-deoxy-D-glucose, and m-fluoro-phenylalanine. The MICs of the antimicrobial drugs amikacin, sparfloxacin, and clarithromycin varied, but overall the MICs for the SmO variant were the lowest. Radiometric assessment of drug-inhibitor combinations by using established x/y determinations revealed enhanced activity when either ethambutol or cerulenin were used in combination with all antimicrobial agents for all variants except the Rg variant of strain 424, for which ethambutol was not effective. Enhanced activity with amino acid analogs was observed with the Rg colony variants of strains 373 and 424. Two potential sites for drug targeting were identified: fatty acid synthesis, for all strains assayed, and peptide biosynthesis, particularly for Rg colony variants that possess previously identified phenylalanine-containing lipopeptides as potential targets for future drug development. Images PMID:7840559

  5. Hexabromocyclododecanes, polybrominated diphenyl ethers, and polychlorinated biphenyls in radiometrically dated sediment cores from English lakes, ~1950-present.

    PubMed

    Yang, Congqiao; Rose, Neil L; Turner, Simon D; Yang, Handong; Goldsmith, Ben; Losada, Sara; Barber, Jonathan L; Harrad, Stuart

    2016-01-15

    This paper reports input fluxes between ~1950 and present, of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDs) in radiometrically-dated sediment cores from 7 English lakes. Fluxes of PCBs at all but one location prone to significant sediment resuspension peaked in the late-1960s/early-1990s, before declining thereafter. Input fluxes of HBCDs at all sites increased from first emergence in the mid-1960s. Thereafter, fluxes peaked in the late-1980s/early-2000s, before declining through to the present, except at the most urban site where HBCD fluxes are still increasing. Trends of PBDEs predominant in the Penta-BDE and Octa-BDE formulations vary between sites. While at some locations, fluxes peaked in the late-1990s/early-2000s; at others, fluxes are still increasing. This suggests the full impact of EU restrictions on these formulations has yet to be felt. Fluxes of BDE-209 have yet to peak at all except one location, suggesting little discernible environmental response to recent EU restrictions on the Deca-BDE product. Strikingly, fluxes of BDE-209 in the most recent core slices either exceed or approach peak fluxes of ?PCBs, implying substantial UK use of Deca-BDE. Excepting HBCDs, inventories of our target contaminants correlated significantly with local population density, implying substantial urban sources. PMID:26433331

  6. Radiometric dating of marine-influenced coal using Re-Os geochronology

    NASA Astrophysics Data System (ADS)

    Tripathy, Gyana Ranjan; Hannah, Judith L.; Stein, Holly J.; Geboy, Nicholas J.; Ruppert, Leslie F.

    2015-12-01

    Coal deposits are integral to understanding the structural evolution and thermal history of sedimentary basins and correlating contemporeous estuarine and fluvial delatic strata with marine sections. While marine shales may readily lend themselves to Re-Os dating due to the dominance of hydrogenous Re and Os, the lack of a chronometer for near-shore sedimentary environments hampers basinwide correlations in absolute time. Here, we employ the Re-Os geochronometer, along with total organic carbon (TOC) and Rock-Eval data, to determine the timing and conditions of a marine incursion at the top of the Matewan coal bed, Kanawha Formation, Pottsville Group, West Virginia, USA. The observed range for hydrogen index (HI: 267-290 mg hydrocarbon/gram total organic carbon) for these coal samples suggests dominance of aliphatic hydrocarbons with low carbon (

  7. NASA IKONOS Radiometric Characterization

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Frisbee, Troy; Zanoni, Vicki; Blonski, Slawek; Daehler, Erik; Grant, Brennan; Holekamp, Kara; Ryan, Robert; Sellers, Richard; Smith, Charles

    2002-01-01

    The objective of this program: Perform radiometric vicarious calibrations of IKQNOS imagery and compare with Space Imaging calibration coefficients The approach taken: utilize multiple well-characterized sites which are widely used by the NASA science community for radiometric characterization of airborne and spaceborne sensors; and to Perform independent characterizations with independent teams. Each team has slightly different measurement techniques and data processing methods.

  8. Radiometric correction procedure study

    NASA Technical Reports Server (NTRS)

    Colby, C.; Sands, R.; Murphrey, S.

    1978-01-01

    A comparison of MSS radiometric processing techniques identified as a preferred radiometric processing technique a procedure which equalizes the mean and standard deviation of detector-specific histograms of uncalibrated scene data. Evaluation of MSS calibration data demonstrated that the relationship between detector responses is essentially linear over the range of intensities typically observed in MSS data, and that the calibration wedge data possess a high degree of temporal stability. An analysis of the preferred radiometric processing technique showed that it could be incorporated into the MDP-MSS system without a major redesign of the system, and with minimal impact on system throughput.

  9. Initial Radiometric Calibration of the AWiFS using Vicarious Calibration Techniques

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Thome, Kurtis; Aaron, David; Leigh, Larry

    2006-01-01

    NASA SSC maintains four ASD FieldSpec FR spectroradiometers: 1) Laboratory transfer radiometers; 2) Ground surface reflectance for V&V field collection activities. Radiometric Calibration consists of a NIST-calibrated integrating sphere which serves as a source with known spectral radiance. Spectral Calibration consists of a laser and pen lamp illumination of integrating sphere. Environmental Testing includes temperature stability tests performed in environmental chamber.

  10. Radiometric Calibration of the AWiFS Using Vicarious Calibration Techniques

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Holekamp, Kara

    2007-01-01

    A radiometric calibration assessment of the AWiFS (Advanced Wide Field Sensor) on the Indian Remote Sensing Resourcesat-1 satellite was performed by the NASA Applied Research & Technology Project Office (formerly the Applied Sciences Directorate) at the John C. Stennis Space Center. A reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with satellite acquisitions and radiative transfer calculations, was used to estimate at-sensor radiance. The AWiFS is a 4-band, multispectral, moderate-resolution (60 m) imaging sensor that operates in the visible through short-wave infrared spectrum and is currently being considered as a Landsat-like alternative. Several study sites near the Stennis Space Center that attempted to span the dynamic range of the sensor were employed. Satellite at-sensor radiance values were compared to those estimated to determine the sensor's radiometric accuracy. The results of this evaluation provide the user community with an independent assessment of the radiometric accuracy of AWiFS image products, which are commercially available through GeoEye. These results are an extension of an independent assessment made by the University of Arizona Remote Sensing Group, the South Dakota State University Satellite Calibration Group & Image Processing Lab, and the NASA Applied Sciences Directorate at the John C. Stennis Space Center the previous year.

  11. Apparatus description and data analysis of a radiometric technique for measurements of spectral and total normal emittance

    NASA Technical Reports Server (NTRS)

    Edwards, S. F.; Kantsios, A. G.; Voros, J. P.; Stewart, W. F.

    1975-01-01

    The development of a radiometric technique for determining the spectral and total normal emittance of materials heated to temperatures of 800, 1100, and 1300 K by direct comparison with National Bureau of Standards (NBS) reference specimens is discussed. Emittances are measured over the spectral range of 1 to 15 microns and are statistically compared with NBS reference specimens. Results are included for NBS reference specimens, Rene 41, alundum, zirconia, AISI type 321 stainless steel, nickel 201, and a space-shuttle reusable surface insulation.

  12. A comparison of four relative radiometric normalization (RRN) techniques for mosaicing H-res multi-temporal thermal infrared (TIR) flight-lines of a complex urban scene

    NASA Astrophysics Data System (ADS)

    Rahman, M. M.; Hay, G. J.; Couloigner, I.; Hemachandran, B.; Bailin, J.

    2015-08-01

    High-spatial and -radiometric resolution (H-res) thermal infrared (TIR) airborne imagery, such as the TABI-1800 (Thermal Airborne Broadband Imager) provide unique surface temperature information that can be used for urban heat loss mapping, heat island analysis, and landcover classifications. For mapping large urban areas at a high-spatial resolution (i.e., sub-meter), airborne thermal imagery needs to be acquired over a number of flight-lines and mosaiced together. However, due to radiometric variations between flight-lines the similar objects tend to have different temperature characteristics on the mosaicked image, resulting in reduced visual and radiometric agreement between the flight-lines composing the final mosaiced output. To reduce radiometric variability between airborne TIR flight-lines, with a view to produce a visually seamless TIR image mosaic, we evaluate four relative radiometric normalization techniques including: (i) Histogram Matching, (ii) Pseudo Invariant Feature (PIF) Based Linear Regression, (iii) PIF-Based Theil-Sen Regression, and (iv) No-Change Stratified Random Samples (NCSRS) Based Linear Regression. The techniques are evaluated on two adjacent TABI-1800 airborne flight-lines (each ?30 km 0.9 km) collected ?25 min apart over a portion of The City of Calgary (with ?30% overlap between them). The performances of these techniques are compared based on four criteria: (i) speed of computation, (ii) ability to automate, (iii) visual assessment, and (iv) statistical analysis. Results show that NCSRS-Based Linear Regression produces the best overall results closely followed by Histogram Matching. Specifically, these two radiometric normalization techniques: (i) increase the visual and statistical agreement between the tested TIR airborne flight-lines (NCSRS Based Linear Regression increases radiometric agreement between flight-lines by 53.3% and Histogram Matching by 52.4%), (ii) produce a visually seamless image mosaic, and (iii) can be rapidly automated within an operational multi-flight-line, multi-temporal mosaic workflow.

  13. Statistical techniques applied to aerial radiometric surveys (STAARS): principal components analysis user's manual. [NURE program

    SciTech Connect

    Koch, C.D.; Pirkle, F.L.; Schmidt, J.S.

    1981-01-01

    A Principal Components Analysis (PCA) has been written to aid in the interpretation of multivariate aerial radiometric data collected by the US Department of Energy (DOE) under the National Uranium Resource Evaluation (NURE) program. The variations exhibited by these data have been reduced and classified into a number of linear combinations by using the PCA program. The PCA program then generates histograms and outlier maps of the individual variates. Black and white plots can be made on a Calcomp plotter by the application of follow-up programs. All programs referred to in this guide were written for a DEC-10. From this analysis a geologist may begin to interpret the data structure. Insight into geological processes underlying the data may be obtained.

  14. A comparison of radiometric correction techniques in the evaluation of the relationship between LST and NDVI in Landsat imagery.

    PubMed

    Tan, Kok Chooi; Lim, Hwee San; Matjafri, Mohd Zubir; Abdullah, Khiruddin

    2012-06-01

    Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses, such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two atmospheric correction methods were used for this study: relative radiometric normalization and the simplified method for atmospheric correction (SMAC) in the solar spectrum. A multi-temporal data set consisting of two sets of Landsat images from the period between 1991 and 2002 of Penang Island, Malaysia, was used to compare NDVI maps, which were generated using the proposed atmospheric correction methods. Land surface temperature (LST) was retrieved using ATCOR3_T in PCI Geomatica 10.1 image processing software. Linear regression analysis was utilized to analyze the relationship between NDVI and LST. This study reveals that both of the proposed atmospheric correction methods yielded high accuracy through examination of the linear correlation coefficients. To check for the accuracy of the equation obtained through linear regression analysis for every single satellite image, 20 points were randomly chosen. The results showed that the SMAC method yielded a constant value (in terms of error) to predict the NDVI value from linear regression analysis-derived equation. The errors (average) from both proposed atmospheric correction methods were less than 10%. PMID:21755424

  15. A comparison of radiometric correction techniques in the evaluation of the relationship between LST and NDVI in Landsat imagery.

    TOXLINE Toxicology Bibliographic Information

    Tan KC; Lim HS; Matjafri MZ; Abdullah K

    2012-06-01

    Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses, such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two atmospheric correction methods were used for this study: relative radiometric normalization and the simplified method for atmospheric correction (SMAC) in the solar spectrum. A multi-temporal data set consisting of two sets of Landsat images from the period between 1991 and 2002 of Penang Island, Malaysia, was used to compare NDVI maps, which were generated using the proposed atmospheric correction methods. Land surface temperature (LST) was retrieved using ATCOR3_T in PCI Geomatica 10.1 image processing software. Linear regression analysis was utilized to analyze the relationship between NDVI and LST. This study reveals that both of the proposed atmospheric correction methods yielded high accuracy through examination of the linear correlation coefficients. To check for the accuracy of the equation obtained through linear regression analysis for every single satellite image, 20 points were randomly chosen. The results showed that the SMAC method yielded a constant value (in terms of error) to predict the NDVI value from linear regression analysis-derived equation. The errors (average) from both proposed atmospheric correction methods were less than 10%.

  16. The Sima de los Huesos hominids date to beyond U/Th equilibrium (>350 kyr) and perhaps to 400-500 kyr: New radiometric dates

    USGS Publications Warehouse

    Bischoff, J.L.; Shamp, D.D.; Aramburu, Arantza; Arsuaga, J.L.; Carbonell, E.; Bermudez de Castro, Jose Maria

    2003-01-01

    The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the Middle Pleistocene cave bear (U. deningeri). Earlier dating estimates of 200 to 320 kyr were based on U-series and ESR methods applied to bones, made inaccurate by unquantifiable uranium cycling. We report here on a new discovery within the Sima de los Huesos of human bones stratigraphically underlying an in situ speleothem. U-series analyses of the speleothem shows the lower part to be at isotopic U/Th equilibrium, translating to a firm lower limit of 350 kyr for the SH hominids. Finite dates on the upper part suggest a speleothem growth rate of c. 1 cm/32 kyr. This rate, along with paleontological constraints, place the likely age of the hominids in the interval of 400 to 600 kyr. ?? 2002 Elsevier Science Ltd. All rights reserved.

  17. Dating human skeletal remains using a radiometric method: biogenic versus diagenetic 90Sr and 210Pb in vertebrae.

    PubMed

    Schrag, Bettina; Uldin, Tanya; Mangin, Patrice; Froidevaux, Pascal

    2012-07-10

    In forensic science, there is a strong interest in determining the post-mortem interval (PMI) of human skeletal remains up to 50 years after death. Currently, there are no reliable methods to resolve PMI, the determination of which relies almost exclusively on the experience of the investigating expert. Here we measured (90)Sr and (210)Pb ((210)Po) incorporated into bones through a biogenic process as indicators of the time elapsed since death. We hypothesised that the activity of radionuclides incorporated into trabecular bone will more accurately match the activity in the environment and the food chain at the time of death than the activity in cortical bone because of a higher remodelling rate. We found that determining (90)Sr can yield reliable PMI estimates as long as a calibration curve exists for (90)Sr covering the studied area and the last 50 years. We also found that adding the activity of (210)Po, a proxy for naturally occurring (210)Pb incorporated through ingestion, to the (90)Sr dating increases the reliability of the PMI value. Our results also show that trabecular bone is subject to both (90)Sr and (210)Po diagenesis. Accordingly, we used a solubility profile method to determine the biogenic radionuclide only, and we are proposing a new method of bone decontamination to be used prior to (90)Sr and (210)Pb dating. PMID:22497702

  18. Relative radiometric correction of QuickBird imagery using the side-slither technique on-orbit.

    SciTech Connect

    Henderson, B. G.; Krause, Keith S.

    2004-01-01

    The QuickBird commercial imaging satellite is a pushbroom system with four multispectral bands covering the visible through near-infrared region of the spectrum and a panchromatic band. 6972 detectors in each MS band and 27888 detectors in the pan band must be calibrated. In an ideal sensor, a uniform radiance target will produce a uniform image. Unfortunately, raw imagery generated from a pushbroom sensor contains vertical streaks caused by variability in detector response, variability in electronic gain and offset, lens falloff, and particulate contamination on the focal plane. Relative radiometric correction is necessary to account for the detector-to-detector non-uniformity seen in raw imagery. A relative gain is calculated for each detector while looking at a uniform target such as an integrating sphere during ground calibrations, diffuser panel, or large desert target on-orbit. A special maneuver developed for QuickBird called the 'Side-Slither' technique is discussed. This technique improves the statistics of a desert target and achieves superior non-uniformity correction in imagery. The 'Side-Slither' technique is compared to standard techniques for calculation of relative gain and shows a reduction in the streaking seen in imagery.

  19. Recent documents dating: an approach using radiocarbon techniques.

    PubMed

    Zavattaro, D; Quarta, G; D'Elia, M; Calcagnile, L

    2007-04-11

    The possibility to develop an absolute technique, independent from the paper conservation conditions, to date recent paper documents (i.e. less than 50 years old) for forensics purposes is discussed. We suggest the possibility to use the curve representing the strong increase in the atmospheric radiocarbon concentration induced in the last 50 years by nuclear weapons tests as reference to date paper documents, with a resolution down to a few months. The results obtained in the analysis of two known age documents are presented together with a first order mathematical model developed in order to take into account the contributions of the different tree rings employed in the paper production. PMID:16872773

  20. New twist on dating: radiocarbon dating techniques applied to air pollution studies

    SciTech Connect

    Porter, G.

    1981-05-01

    This paper deals with the problem of urban air pollution and to what extent it is caused by the burning of fossil fuels at factories or in cars, and to what extent it is due to the breathing processes of trees or the burning of natural fuels like wood. With the use of radiocarbon dating techniques the distinction between the pollutants can be made. The article describes the design of the gas proportional counter used to measure the extremely small samples of carbon in polluted air. (KRM)

  1. Sun Photometer Laser and Lamp Based Radiometric Calibrations; Comparison with the Langley Technique and Implications on Remote Sensing

    NASA Astrophysics Data System (ADS)

    Souaidia, N.; Pietras, C.; Brown, S. W.; Lykke, K. R.; Frouin, R.; Deschamps, P.; Fargion, G.; Johnson, B. C.

    2002-12-01

    Satellite-based remote sensing of the earth is a valuable data source for biological and oceanic studies. However when using remote sensing, it is necessary to correct the measured signal for atmospheric effects. As aerosols play a major role in atmospheric scattering, correcting algorithms based on Aerosol Optical Thickness (AOT) data have been developed to describe the scattering of radiation by aerosols. AOT data are collected by filter radiometers measuring the solar irradiance. The AOT is then retrieved applying the Beer-Bouger-Lambert Law to those measurements. Two radiometers, called Satellite Validation for Marine Biology and Aerosol Determination (SimbadA), were calibrated in this study. These instruments measure the upwelling radiance from the ocean as well as the solar irradiance, providing information on both marine reflectance and AOT. The goals of this study were to calibrate the radiometers using independent methods, evaluate the uncertainties for each method, and assess the influence of the results in terms of the science requirements. The radiometers were calibrated in irradiance and radiance mode using a monochromatic, laser-illuminated integrating sphere, in radiance mode using two different lamp-illuminated integrating spheres, and in irradiance mode using the Langley technique. First, a limited characterization of the instrument was conducted. The instrument's temporal stability and its spectral out-of-band response were evaluated. The instrument was then calibrated in radiance mode using a laser-illuminated integrating sphere that overfilled its field of view (FOV). The absolute radiance responsivity from this calibration was compared to results from measurements of two calibrated lamp illuminated spheres. The first comparison, with the NIST portable radiometric source (NPR), was a validation as good agreement between the two methods has been reported in previous studies. The second comparison was with the Hardy sphere from the Goddard Space Flight Center (GSFC) of the National Aeronautics and Space Administration (NASA). In this comparison the NASA radiance scale was compared to NIST's. A disagreement was observed and will be discussed. Finally, an absolute irradiance responsivity calibration was performed with the laser based facility using a small integrating sphere that underfilled the instrument's FOV. This was done in order to do a comparison with the Langley technique, which is based on irradiance measurements. Using the absolute spectral responsivity obtained with the laser based calibration and a solar irradiance spectrum, the expected Top of the Atmosphere signal (V0) was determined and compared with the V0 obtained from the Langley calibration. Results will be presented and implications for derived AOT discussed.

  2. (25143) Itokawa: The power of radiometric techniques for the interpretation of remote thermal observations in the light of the Hayabusa rendezvous results*

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  3. New Sakmarian ages for the Rio Bonito formation (Paraná Basin, southern Brazil) based on LA-ICP-MS U-Pb radiometric dating of zircons crystals

    NASA Astrophysics Data System (ADS)

    Cagliari, Joice; Lavina, Ernesto Luiz Correa; Philipp, Ruy Paulo; Tognoli, Francisco Manoel Wohnrath; Basei, Miguel Angelo Stipp; Faccini, Ubiratan Ferrucio

    2014-12-01

    Two ash fall beds (tonstein) sampled from the post-glacial Permian deposits of the Paraná Basin have provided new U-Pb radiometric age constraints for this stratigraphic interval. The zircon grains were recovered from tonstein layers interbedded with fine-grained and carbonaceous lithologies in the middle portion of the Rio Bonito Formation. In both samples, the dominant population is interpreted as generated by explosive volcanism, as having formed immediately before the eruption. Based on 238U/206Pb, the selected zircon grains from the dominant population have weighted mean ages of 290.6 ± 2.8 Ma and 281.7 ± 3.2 Ma, corresponding to the Sakmarian and Kungurian ages in the Cisuralian epoch, respectively. These ages constrain the time of the deposition of the tonstein horizons and have important stratigraphic implications for the Late Paleozoic evolution of both the Paraná Basin and the southwestern region of Gondwana. The results presented here and the radiometric data already published suggest that deposition of the post-glacial coal-bearing deposits of the Rio Bonito Formation was probably initiated before the Early Permian. Thus, we infer that the climate had already ameliorated by this period in order to allow for the formation and accumulation of peat in this region of Gondwana.

  4. Simplified Vicarious Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Stanley, Thomas; Ryan, Robert; Holekamp, Kara; Pagnutti, Mary

    2010-01-01

    A measurement-based radiance estimation approach for vicarious radiometric calibration of spaceborne multispectral remote sensing systems has been developed. This simplified process eliminates the use of radiative transfer codes and reduces the number of atmospheric assumptions required to perform sensor calibrations. Like prior approaches, the simplified method involves the collection of ground truth data coincident with the overpass of the remote sensing system being calibrated, but this approach differs from the prior techniques in both the nature of the data collected and the manner in which the data are processed. In traditional vicarious radiometric calibration, ground truth data are gathered using ground-viewing spectroradiometers and one or more sun photometer( s), among other instruments, located at a ground target area. The measured data from the ground-based instruments are used in radiative transfer models to estimate the top-of-atmosphere (TOA) target radiances at the time of satellite overpass. These TOA radiances are compared with the satellite sensor readings to radiometrically calibrate the sensor. Traditional vicarious radiometric calibration methods require that an atmospheric model be defined such that the ground-based observations of solar transmission and diffuse-to-global ratios are in close agreement with the radiative transfer code estimation of these parameters. This process is labor-intensive and complex, and can be prone to errors. The errors can be compounded because of approximations in the model and inaccurate assumptions about the radiative coupling between the atmosphere and the terrain. The errors can increase the uncertainty of the TOA radiance estimates used to perform the radiometric calibration. In comparison, the simplified approach does not use atmospheric radiative transfer models and involves fewer assumptions concerning the radiative transfer properties of the atmosphere. This new technique uses two neighboring uniform ground target areas having different reflectance values. The target areas can be natural or artificial and must be large enough to minimize adjacent-pixel contamination effects. The radiative coupling between the atmosphere and the terrain needs to be approximately the same for the two targets. This condition can be met for relatively uniform backgrounds when the distance between the targets is within a few hundred meters. For each target area, the radiance leaving the ground in the direction of the satellite is measured with a radiometrically calibrated spectroradiometer. Using the radiance measurements from the two targets, atmospheric adjacency and atmospheric scattering effects can be subtracted, thereby eliminating many assumptions about the atmosphere and the radiative interaction between the atmosphere and the terrain. In addition, the radiometrically calibrated spectroradiometer can be used with a known reflectance target to estimate atmospheric transmission and diffuse- to-global ratios without the need for ancillary sun photometers. Several comparisons between the simplified method and traditional techniques were found to agree within a few percent. Hence, the simplified method reduces the overall complexity of performing vicarious calibrations and can serve as a method for validating traditional radiative transfer models

  5. Geochronological data from the Faxinal coal succession, southern Paran Basin, Brazil: A preliminary approach combining radiometric U-Pb dating and palynostratigraphy

    NASA Astrophysics Data System (ADS)

    Guerra-Sommer, Margot; Cazzulo-Klepzig, Miriam; Menegat, Rualdo; Formoso, Milton Luiz Laquintinie; Basei, Miguel ngelo Stipp; Barboza, Eduardo Guimares; Simas, Margarete Wagner

    2008-03-01

    A radiometric zircon age of 285.4 8.6 Ma (IDTIMS U-Pb) is reported from a tonstein layer interbedded with coal seams in the Faxinal coalfield, Rio Grande do Sul, Brazil. Calibration of palynostratigraphic data with the absolute age shows that the coal depositional interval in the southern Paran Basin is constrained to the Sakmarian. Consequently, the basal Gondwana sequence in the southern part of the basin should lie at the Carboniferous-Permian boundary, not within the Sakmarian as previously considered. The new results are significant for correlations between the Paran Basin and the Argentinian Paganzo Basin (302 6 Ma and 288 7 Ma) and with the Karoo Basin, specifically with the top of the Dwyka Tillite (302 3 Ma and 299.2 3.2 Ma) and the lowermost Ecca Group (288 3 Ma and 289.6 3.8 Ma). The evidence signifies widespread latest Carboniferous volcanic activity in western Gondwana.

  6. TES radiometric assessment

    NASA Technical Reports Server (NTRS)

    Worden, H.; Sarkissian, E.; Bowman, K.; Fisher, B.; Rider, D.; Aumann, H. H.; Apolinski, M.; Debaca, R. C.; Gluck, S.; Madatyan, M.; McDuffie, J.; Tremblay, D.; Shephard, M.; Cady-Pereira, K.; Tobin, D.; Revercomb, H.

    2005-01-01

    TES is an infrared Fourier transform spectrometer on board the EOS-Aura spacecraft launched July 15, 2004. Improvements to the radiometric calibration and consequent assessment of radiometric accuracy have been on-going since launch.

  7. Teaching the Mathematics of Radioactive Dating.

    ERIC Educational Resources Information Center

    Shea, James H.

    2001-01-01

    Describes a method used to teach the concept of radiometric dating using mathematical equations. Explores the lack of information in textbooks on how to solve radiometric dating problems using mathematical concepts. (SAH)

  8. Cryogenic Separation Of Glauconite And Foraminifera From The Cretaceous/Paleogene Boundary Interval At Nasi?w, Poland, For Radiometric Dating And Stratigraphy

    NASA Astrophysics Data System (ADS)

    Wjtowicz, Artur; Pie?kos, Tomasz; Ha?as, Stanis?aw; Peryt, Danuta; Durakiewicz, Tomasz; M?ynek, Agnieszka

    2015-03-01

    We have demonstrated that cryogenic separation of glauconite and foraminifera from the host rock allows to preserve the integrity of extracted specimens, assures minimal damage and causes no artificial fractionation. The K/Ar dating of two glauconite samples from Cretaceous/Paleogene boundary in the Nasi?w outcrop yields 62.0 and 66.3 Ma. The discrepancy in these dates, much larger than expected from analytical precision, may result from too low %K, which was 5.91 and 5.73, respectively.

  9. Radiometric ages of Tennessee rocks

    SciTech Connect

    Corgan, J.X.; Bradley, M.W.

    1983-01-01

    This report compiles and summarizes all known radiometric age determinations based on bedrock samples from Tennessee. Data are available for 89 sites. Specimens record both igneous and metamorphic events ranging in age from 1.3 billion to 220 million years before present. Tennessee rocks have been dated by techniques that measure the results of four different kinds of radioactive decay: thorium-lead, uranium-lead, potassium-argon, and rubidium-strontium. Most determinations meet normal scientific standards for reliability. This study focuses on clarifying published data by bringing together geochemical, geological, and geographical information for each site. In addition to data on the age of bedrock samples, this study presents basic information on the ages of meteorites from Tennessee and on the ages of sediments and organic remains from Ice Age fossil sites and more recent archeological sites. While bedrock ages are the thrust of the report, other kinds of absolute age determinations are briefly discussed. 98 references, 11 figures, 3 tables.

  10. Detailed geologic field mapping and radiometric dating of the Abanico Formation in the Principal Cordillera, central Chile: Evidence of protracted volcanism and implications for Cenozoic tectonics

    NASA Astrophysics Data System (ADS)

    Mosolf, J.; Gans, P. B.; Wyss, A. R.; Cottle, J. M.

    2011-12-01

    Many aspects of the long-term evolution of intra-arc processes remain poorly understood, including temporal trends in magmatism, temporal and spatial patterns of volcanism, and styles of arc deformation. The Abanico Formation in the Principal Cordillera of central Chile is a thick, well-exposed section of volcanogenic strata providing a superb locale for the investigation of continental arc dynamics over a 60+ myr timescale. In this study, eight new litho-stratigraphic members of the Abanico Formation are described and mapped in the Ro Tinguiririca river area. Mapping and field observations show the Abanico Formation measures up to ~2.5 km in composite stratigraphic thickness. The lower ~1.1 km of the section (> 46 Ma) is dominated by andesitic breccias interbedded with andesite, basaltic andesite, and olivine basalt lavas. The upper 1.4 km of the section (< 46 Ma) consists of volcaniclastic sandstone interbedded with abundant dacitic tuffs and minor andesite, basaltic andesite, and basalt flows. Nineteen new LA-MC-ICPMS U-Pb zircon ages and ten new 40Ar/39Ar whole rock and plagioclase ages obtained for the Abanico Formation clarify ambiguous field relationships and provide a robust chrono-stratigraphic framework spanning ~72 to 11 Ma; these new ages significantly revise the maximum mid-Tertiary age for the Abanico Formation previously established by the mammal fossil record. The map units are cut by numerous dacitic to gabbroic dikes and sills with ages spanning the Eocene to Pliocene. The Abanico Formation is overlain in angular unconformity by Pliocene and Quaternary volcanics composed mainly of andesite, basaltic andesite, and basalt lavas. A strong deformational overprint has tilted, folded, and faulted the Abanico map units. Fold axes and reverse faults, both east and west directed, are generally N-S trending. Reverse faults achieve up to ~50 Ma of stratigraphic separation, placing Campanian strata on Miocene rocks with up to ~2 km of vertical throw. The Abanico Formation is also offset by numerous steeply-dipping, oblique-slip faults with 100+ meters of slip. The Abanico Formation is interpreted to have been emplaced within an active arc, with progressively more evolved material being erupted up section during the Campanian to Miocene, followed by more mafic volcanism during the Pliocene and Quaternary. Radiometric ages bounding intra-formational unconformities imply that shortening commenced no later than the early Miocene, with an older deformational episode possibly preceding it. Results of this study clearly demonstrate the age of the Abanico Formation extends from Campanian to Miocene, requiring a significant revision of the current mid-Tertiary age paradigm for the Abanico Formation in addition to the revision of the prevailing tectonic models for the Principal Cordillera, including the timing of eastward arc migration.

  11. Synthetic Aperture Radar (SAR) radiometric characterization

    NASA Astrophysics Data System (ADS)

    Ilsemann, Fred; Haimovich, Alex; Geisz, Andy; Cho, Peter; Evans-Morgis, Jeanette; Verdi, Jim

    1992-05-01

    Integrated SAR radiometric calibration procedures developed at the Naval Air Development Center are described which make it possible to compare SAR imagery collected at different times and under different conditions. Techniques for relative and absolute calibration were applied to two data sets of SAR imagery containing corner reflectors to evaluate SAR radiometric characterization techniques for the P3 SAR system. The procedures included compensation for power range attenuation, an antenna elevation pattern, and targets RCS response vs. aspect angle.

  12. A two step linear statistical technique using leaps and bounds procedure for retrieval of geophysical parameters from microwave radiometric data

    NASA Technical Reports Server (NTRS)

    Kakar, R. K.; Pandey, P. C.

    1983-01-01

    A linear statistical technique using a 'leaps and bounds' procedure (Furnival and Wilson, 1974) is developed for retrieving geophysical parameters from remote measurements. It is used for retrieving sea surface temperatures from the Scaning Multichannel Microwave Radiometer (SMMR) on Seasat. The technique uses an efficient algorithm to select the best fixed-size subset of the 10 SMMR channels for linearly retrieving a given geophysical parameter. The 5-channel subset (6.6V, 6.6H 10H, 18V, 21H), where V and H refer to, respectively, the vertical and horizontal polarizations and the numbers are the channel frequencies in gigahertz, gives the minimum rms error in estimating the sea surface temperature. A comparison with ground truth indicates that the algorithm infers the temperature with an rms accuracy of better than 1.5 K under most environmental conditions. A quality control procedure which is seen as holding promise for further improving the accuracy is proposed.

  13. Radiometric Dating of Folds: A new approach to determine the timing of deformation at shallow-crustal conditions, with examples from the Mexican Fold-Thrust Belt

    NASA Astrophysics Data System (ADS)

    Fitz Diaz, E.; van der Pluijm, B. A.

    2012-12-01

    We are developing a robust method to obtain absolute ages of folds that were formed at shallow crustal conditions. The method takes advantage of illite neocrystallization in folded, clay-bearing layers and the ability to obtain accurate retention and total gas ages from small size fractions using encapsulated Ar analysis, analogous to prior work on fault gouge dating. We illustrate our approach in folded Cretaceous shale-bentonitic layers that are interbedded with carbonates of the Zimapn and the Tampico-Misantla cretaceous basins in central-eastern Mexico. Basinal carbonates were buried by syntectonic turbidites and inverted during the formation of the Mexican Fold-Thrust in the Late Cretaceous. Results were obtained from four chevron folds that are representative of different stages of deformation, burial/temperature conditions and location within this thin-skinned orogenic wedge: two from the Zimapn Basin (Folds 1 and 2) in the west and two from the Tampico-Misantla Basin (Folds 3 and 4) in the east. Mineralogic compositions and variations in illite-polytypes, crystallite-size (CS) and Ar/Ar ages were obtained from size fractions in limbs and hinges of folded layers. Ar retention ages produce a folding age of ~81 Ma for Fold 1 and ~69 Ma for Fold 2, which are fully consistent with stratigraphic limits from syn-orogenic turbidities and observed overprinting events in the Mexican Fold-Thrust Belt. The total gas age of Fold 3, on the easternmost margin of the Tampico-Misantla Basin is similar to that of Fold 2, indicating that the second event is regional in scale. In addition to presenting a new, reliable method to constrain the timing of local deformation, we interpret folding and associated clay neo-mineralization in terms of the regional burial history, and localization and propagation of deformation within a heterogeneous orogenic wedge involving progressive deformation of two basins separated by a platform block.

  14. Range and effectiveness of the unspiked K-Ar technique constrained by cross calibration with 40Ar-39Ar dated quaternary lavas

    NASA Astrophysics Data System (ADS)

    Guillou, H.; Scaillet, S.; Singer, B.; Perez Torrado, F. J.; Carracedo, J. C.

    2003-04-01

    The unspiked K-Ar dating method ("Cassignol" technique) can distinguish very small amounts of 40Ar* in late Quaternary lavas. Nevertheless, this particular technique, which is a sensitive and rapid dating method, relies on the basic assumptions of the 40K-40Ar chronometer. The Achilles' tendon of the method is that we cannot verify the isotopic composition of the initial argon trapped in the samples. In other terms, we must assume that, at the time of formation, the 40Ar-36Ar ratio of the sample was the modern atmospheric value (295.5). A direct comparison between the magnetic polarity of some dated samples and their radiometric ages, using the APTS reference framework, demonstrates that some unaltered groundmass samples may give erroneously old ages. These overestimations, for the most part, probably reflect excess argon. This problem is obvious for some lavas on Gran Canaria which recorded the Reunion event. In the same island, several K-Ar ages which are coherent with the magnetic polarity of the samples coincide with magnetic reversals or event boundaries. However, the inconsistencies observed between some samples and the APTS, suggest that these age determinations must be considered carefully, if they are to be used to update the GPTS. Combined K-Ar and 40Ar-39Ar experiments on multiple subsamples of groundmass separated from individual basaltic lava flows facilitates a comparison of the two techniques and provides examples of the complementary information provided by each. These experiments also confirm the effectiveness of the two techniques to date key events such as geomagnetic field reversals and climatic changes. Examples of our results from Quaternary lavas of Fuerteventura, Gran Canaria and from Patagonia, will demonstrate the effectiveness of this combined approach.

  15. Unravelling the chronology and evolution of the Pleistocene-Holocene basin in the hanging-wall of the 2009 L'Aquila earthquake fault by multidisciplinary approach (paleomagnetism, palaeontology, geochemistry and radiometric dating) on a 150 m deep hole

    NASA Astrophysics Data System (ADS)

    Mochales, T.; Porreca, M.; Smedile, A.; Buratti, N.; Macri', P.; Di Chiara, A.; Sagnotti, L.; Speranza, F.; Amoroso, S.; Nicolosi, I.; D'ajello Caracciolo, F.; Carluccio, R.; Di Giulio, G.; Vassallo, M.; Villani, F.; Civico, R.

    2013-12-01

    The Mw=6.1 L'Aquila earthquake struck the central Apennines (Italy), on April 6th, 2009. INSAR data showed that the maximum subsidence of ca. 15 cm was located in the continental Aterno Basin, partly controlled by the Paganica extensional fault, yielding the L'Aquila earthquake. Preliminary geological and geophysical surveys have been performed in the depocenter of the Aterno Basin to figure out the underground configuration and determine the best location for a deep hole. The drilling was performed in May-June 2013, recovering 151 m of continental Holocene and Pleistocene sediments. The upper sandy-silty sequence (41 m), interbedded with gravels, is interpreted as fluvial-alluvial origin. The lower clayey-silty sequence, interpreted as lacustrine sediments, continues downward until the bottom (disrupted by 30 m of gravels). The continuous sediment record of the hole is being processed along three stages: i) Description consists of the elaboration of stratigraphical logs, color description and photographic record of the core. The second stage consists of sampling for the different analyses. ii) Continuous samples (U-Channel) were collected from the undisturbed centre of the core for paleomagnetic measurements. Additional samples were collected in the clayey-silty fraction (10 to 25 cm spacing) for calcimetry, geochemical, palynological and ostracoda fauna analysis. Finally, individual levels rich in organic matter and charcoal were sampled for radiometric datings. Iii) The measurements include magnetic susceptibility, paleomagnetic and rock magnetic properties, content of calcium carbonate and 16/18 oxygen ratio, crumble and classification of fossils for pollens and ostracods analyses. Paleomagnetic analyses will hopefully allow us to obtain experimental constraints for dating the Holocene-Pleistocene sediments of the Aterno Basin. The presence of Carbon-14 in organic materials can yield absolute dating. Palynology, oxygen ratio and calcium carbonate content will provide information about the environmental and climatic variations and paleotemperature of the water during sedimentation. The study of ostracods will provide information about the paleonvironment (e.g. water depth variations). Geotechnical tests and diffractometric analysis will document the mechanical properties and mineralogical composition of the lacustrine deposits. All the results, along with sedimentological studies, will be integrated to evaluate the occurrence of eventual ciclicities and the degree of inter-relation between the measured parameters. The final aim is to evaluate a possible correlation between the sedimentary events and activation of local extensional structures in the geological past, observe their recurrence (if any) in recent geological times and propose a reconstruction of the Pleistocene evolution of the Aterno Basin.

  16. Radiometric assays for glycerol, glucose, and glycogen

    SciTech Connect

    Bradley, D.C.; Kaslow, H.R. )

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with (32P)ATP and glycerokinase, residual (32P)ATP is hydrolyzed by heating in acid, and free (32P)phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays.

  17. Using Melting Ice to Teach Radiometric Dating.

    ERIC Educational Resources Information Center

    Wise, Donald Underkofler

    1990-01-01

    Presented is an activity in which a mystery setting is used to motivate students to construct their own decay curves of melting ice used as an analogy to radioactive decay. Procedures, materials, apparatus, discussion topics, presentation, and thermodynamics are discussed. (CW)

  18. NASA IKONOS Radiometric Characterization

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Ryan, Robert; Holekamp, Kara; Zanoni, Vicki

    2002-01-01

    The objective of this project is to perform radiometric vicarious calibrations of IKONOS satellite imagery and compare with Space Imaging calibration coefficients. This viewgraph presentation describes characterization undertaken at Lunar Lake Playa, Nevada; and Stennis Space Center, Mississippi.

  19. NASA IKONOS Radiometric Characterization

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Ryan, Robert E.; Kelly, Michelle; Holekamp, Kara; Daehler, Erik; Zanoni, Vicki; Schiller, Stephen; Thome, Kurtis

    2002-01-01

    NASA acquired imagery from the IKONOS satellite as part of its Scientific Data Purchase (SDP) program, which purchases scientific data sets from commercial sources. This viewgraph presentation describes the IKONOS satellite and its sensors, and then gives an overview of characterization efforts undertaken by NASA in cooperation with other government agencies. The characterization included relative radiometric correction, absolute radiometric characterization of data from Lunar Lake Playa, Nevada, and calibration of data from Stennis Space Center, Mississippi.

  20. 40Ar/39Ar technique of KAr dating: a comparison with the conventional technique

    USGS Publications Warehouse

    Brent, Dalrymple G.; Lanphere, M.A.

    1971-01-01

    K-Ar ages have been determined by the 40Ar/39Ar total fusion technique on 19 terrestrial samples whose conventional K-Ar ages range from 3.4 my to nearly 1700 my. Sample materials included biotite, muscovite, sanidine, adularia, plagioclase, hornblende, actinolite, alunite, dacite, and basalt. For 18 samples there are no significant differences at the 95% confidence level between the KAr ages obtained by these two techniques; for one sample the difference is 4.3% and is statistically significant. For the neutron doses used in these experiments (???4 ?? 1018 nvt) it appears that corrections for interfering Ca- and K-derived Ar isotopes can be made without significant loss of precision for samples with K/Ca > 1 as young as about 5 ?? 105 yr, and for samples with K/Ca < 1 as young as about 107 yr. For younger samples the combination of large atmospheric Ar corrections and large corrections for Ca- and K-derived Ar may make the precision of the 40Ar/39Ar technique less than that of the conventional technique unless the irradiation parameters are adjusted to minimize these corrections. ?? 1971.

  1. Developing OSL Geological Dating Techniques for Use on Future Missions to Mars

    NASA Technical Reports Server (NTRS)

    Blair, M. W.; Kalchgruber, R.; Deo, S.; McKeever, S. W. S.

    2005-01-01

    The surface of Mars has been subject to aeolian, fluvial, and periglacial activity in the (relatively) recent past. Unfortunately, chronological dating of recent events on Mars is difficult as the errors associated with crater counting are comparable to younger ages (approx. 1 Ma). Consequently, techniques to quantify the ages of geological processes on Mars have become an important area of research. Optically stimulated luminescence (OSL) dating is one candidate technique for in-situ dating of the deposition of Martian surface sediments. This method can aid in developing a geological and climatic history of the last million years on Mars. The current paper addresses some of the challenges and progress associated with developing OSL as a viable in-situ dating technique for Mars. Some of the challenges include the mineral composition, the effectiveness of solar resetting under Martian conditions, the temperature regime, and determining the natural dose rate on Mars. All of these topics are currently under investigation, and some preliminary results are presented.

  2. Collagen Fingerprinting: A New Screening Technique for Radiocarbon Dating Ancient Bone.

    PubMed

    Harvey, Virginia L; Egerton, Victoria M; Chamberlain, Andrew T; Manning, Phillip L; Buckley, Michael

    2016-01-01

    Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six 14C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 25 to 1588 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated 14C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 14C analysis. PMID:26938469

  3. Collagen Fingerprinting: A New Screening Technique for Radiocarbon Dating Ancient Bone

    PubMed Central

    Harvey, Virginia L.; Egerton, Victoria M.; Chamberlain, Andrew T.; Manning, Phillip L.; Buckley, Michael

    2016-01-01

    Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six 14C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 ± 25 to 1588 ± 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated 14C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 14C analysis. PMID:26938469

  4. Cation-ratio dating: A new rock varnish age-determination technique

    NASA Astrophysics Data System (ADS)

    Dorn, Ronald I.

    1983-07-01

    Rock varnish coats many surfaces of geomorphic and archaeologic interest in arid lands. All varnish dating techniques are limited by the time lag between the exposure of a surface to subaerial processes and the onset of varnishing. They are valid only where manganese is not remobilized after deposition, for example, in most arid environments. The premise of a new age-determination method, cation-ratio dating, is that the ratio of the more mobile cations (e.g., K and Ca) to titanium in varnish decreases with time. Although there are many inherent assumptions and potential limitations, cation-ratio dating has been verified on relative age-sequences from a Death Valley debris cone, Negev Desert talus flatirons, and prehistoric lake levels at Searles Lake in California. Varnish cation ratios have been calibrated to independently dated surfaces in the Coso volcanic field and vicinity in California. Tentative absolute dates have been assigned to geomorphic surfaces in the Coso area. Cation ratios have been used to distinguish relative ages of archaeologic artifacts in southwestern North America and to demonstrate that varnish at the South Stoddard locality, Mojave Desert, did not form in 25 yr.

  5. U-series dating of impure carbonates: An isochron technique using total-sample dissolution

    USGS Publications Warehouse

    Bischoff, J.L.; Fitzpatrick, J.A.

    1991-01-01

    U-series dating is a well-established technique for age determination of Late Quaternary carbonates. Materials of sufficient purity for nominal dating, however, are not as common as materials with mechanically inseparable aluminosilicate detritus. Detritus contaminates the sample with extraneous Th. We propose that correction for contamination is best accomplished with the isochron technique using total sample dissolution (TSD). Experiments were conducted on artificial mixtures of natural detritus and carbonate and on an impure carbonate of known age. Results show that significant and unpredictable transfer of radionuclides occur from the detritus to the leachate in commonly used selective leaching procedures. The effects of correcting via leachate-residue pairs and isochron plots were assessed. Isochrons using TSD gave best results, followed by isochron plots of leachates only. ?? 1991.

  6. Radiometric instrumentation and measurements guide for photovoltaic performance testing

    SciTech Connect

    Myers, D.

    1997-04-01

    The Photovoltaic Module and Systems Performance and Engineering Project at the National Renewable Energy Laboratory performs indoor and outdoor standardization, testing, and monitoring of the performance of a wide range of photovoltaic (PV) energy conversion devices and systems. The PV Radiometric Measurements and Evaluation Team (PVSRME) within that project is responsible for measurement and characterization of natural and artificial optical radiation which stimulates the PV effect. The PV manufacturing and research and development community often approaches project members for technical information and guidance. A great area of interest is radiometric instrumentation, measurement techniques, and data analysis applied to understanding and improving PV cell, module, and system performance. At the Photovoltaic Radiometric Measurements Workshop conducted by the PVSRME team in July 1995, the need to communicate knowledge of solar and optical radiometric measurements and instrumentation, gained as a result of NREL`s long-term experiences, was identified as an activity that would promote improved measurement processes and measurement quality in the PV research and manufacturing community. The purpose of this document is to address the practical and engineering need to understand optical and solar radiometric instrument performance, selection, calibration, installation, and maintenance applicable to indoor and outdoor radiometric measurements for PV calibration, performance, and testing applications. An introductory section addresses radiometric concepts and definitions. Next, concepts essential to spectral radiometric measurements are discussed. Broadband radiometric instrumentation and measurement concepts are then discussed. Each type of measurement serves as an important component of the PV cell, module, and system performance measurement and characterization process.

  7. Small satellite radiometric measurements

    SciTech Connect

    Weber, P.G.

    1991-01-01

    A critical need for the Mission to Planet Earth is to provide continuous, well-calibrated radiometric data for the radiation budget. This paper describes a new, compact, flexible radiometer which will provide both spectrally integrated data and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted vehicles (RPVs). 12 refs., 2 figs.

  8. Inspection of an end quenched 0.15%-0.2% C, 0.6%-0.9% Mn steel jominy bar with photothermal radiometric techniques

    NASA Astrophysics Data System (ADS)

    Liu, Yue; Baddour, Natalie; Mandelis, Andreas; Wang, Chinhua

    2004-08-01

    The effect of the cooling rate on hardness and thermal conductivity in a metallurgical Jominy bar made of 0.15%-0.2% C, 0.6%-0.9% Mn (AISI 1018) steel, by means of a water end-quenched heat treatment process without diffusion-controlled case depth, is studied with photothermal radiometry (PTR). It is concluded that our two PTR techniques, common-mode rejection demodulation and conventional 50% duty-cycle square-wave frequency scan, are sensitive to low hardness values and gradients, unlike the high values all previous photothermal studies have dealt with to-date. Both PTR methods have yielded an anticorrelation between thermal conductivity and microhardness in this case as in previous cases with heat-treated and diffusion-controlled case depth profiles. It is shown that the cooling rate strongly affects both hardness and thermal conductivity in the Jominy-bar heat-treating process.

  9. The ID-KArD technique: In-situ dating on Mars

    NASA Astrophysics Data System (ADS)

    Cartwright, J. A.; Farley, K. A.; Hurowitz, J.; Asimow, P. D.; Jacobson, N. S.

    2013-12-01

    The ability to measure absolute ages on the Martian surface is crucial for understanding the planet's evolution. A detailed geological history of the Moon has been determined through analysis of returned samples from specific units, and relative ages calculated by crater counting techniques. However, without returned samples or in-situ dating analyses, we lack absolute age markers for Mars and thus cannot accurately or precisely date its well-documented surface. Instead, we have relied on an estimated Mars/Moon cratering ratio and relative crater counting techniques in an attempt to calculate surface ages and classify geological units. The use of such relative parameters diminishes the precision and accuracy for surface age calculations, and thus highlights the need for independent age determinations from returned samples or in-situ dating. In this research, we describe our technique - ID-KArD (Isotope Dilution K-Ar Dating) - intended for in-situ age dating of geological units on the Martian surface. ID-KArD resolves two challenges that have previously obstructed in-situ age dating on Mars: 1) High fusion temperatures are avoided with the use of a lithium-borate flux; 2) Sample mass measurement is not required, due to the addition of an isotope dilution doubly-spiked glass. The glass has a known 39Ar/41K ratio, which removes the need for concentration measurements. Thus, only isotope ratios are required for a K-Ar age determination. ID-KArD has the potential to address Mars chronology inaccuracies, and would be a suitable technique for consideration on future missions. In the first phase of ID-KArD proof of concept, we selected a Viluy trap basalt (K2O ~ 0.7 wt%), with concordant K-Ar and Ar-Ar ages of 354.3 3.5 and 357.7 1.4 Ma respectively (Courtillot et al., 2010). An aliquot was combined into a crucible with the flux and the spike glass for separate Ar (MAP 215:50, Caltech), followed by K (KEMS, GRC) isotopic analysis. Combining our results, we obtained an age of 351 19 Ma (Farley et al., 2013), in good agreement with the previously published ages. For the second phase, we have designed and built a single instrument, capable of analysing both Ar and K from a single sample. The instrument includes two ionisation sources for separate K (thermal) and Ar (electron impact) ionsiation, and a quadrupole mass spectrometer. In addition, we have designed a sample heating mechanism that allows degassing of flux prior to sample addition, and achieves temperatures in the range of the SAM oven on Curiosity. Thus far, the instrument has successfully measured both isotopic systems, and following further testing in the coming weeks, we will date Martian surface analogues, age standards, and finally meteoritic material.

  10. Landsat thematic mapper radiometric calibration study

    SciTech Connect

    Wukelic, G.E.; Gibbons, D.E.; Foote, H.P.; Martucci, L.M.

    1987-08-01

    The intent was to develop and test analytical techniques that will enhance the scientific and technical exploitation of digital multispectral data. The thrust involved radiometric calibration efforts aimed at determining the bias and validity in absolute temperature determinations using TM band 6 data. Other objectives included: looking at spectral characterization; change detection; combined reflective and emissive data use; and mixed pixel and atmospheric adjustments. To date, six TM data sets (five day scenes and one night scene) have been analyzed. Calibration accuracy of the water and non-water satellite-determined temperatures, using atmospherically corrected radiance values determined from LOWTRAN 6 with local radiosonde, non-local radiosonde, and LOWTRAN 6 model atmospheres, have been studied. Thermal values for non-water pixels have recently been determined. Extensive progress has been made in validating our calibration methodology, analyzing TM5-band 6 data sets for water and non-water pixels, verifying the mixed pixel and atmospheric adjustment methodologies, considering the quantitative effects of clouds and emissivities on absolute temperature determinations, and in conducting initial experiments relative to band 7 calibration.

  11. First dating of groundwater with Atom Trap Trace Analysis of 39Ar - technique

    NASA Astrophysics Data System (ADS)

    Ritterbusch, Florian; Ebser, Sven; Welte, Joachim; Reichel, Thomas; Kersting, Arne; Purtschert, Roland; Aeschbach-Hertig, Werner; Oberthaler, Markus K.

    2013-04-01

    The importance of 39Ar as a dating tracer for the time range between 50 and 1000 years has clearly been identified [1]. So far, it has been routinely accessible only by Low-Level-Counting (LLC) in the underground laboratory in Bern requiring a sample size of several tons of water and a measuring time of several weeks [2]. Here we report on the first dating results with 39Ar using an atom optical technique known as Atom Trap Trace Analysis (ATTA). This method has been developed for rare krypton isotopes in the past decade and is now available for routine analysis [3]. However, the applicability of ATTA to 39Ar has only been demonstrated in a proof of principle experiment [4]. We will discuss the essential experimental improvements that were necessary for bringing this method to the level of dating real samples. Our apparatus achieves an atmospheric 39Ar-count-rate of 4.1(3) atoms/h, which corresponds to an 18-fold improvement over the reported results in [4]. Based on that, we dated a groundwater sample of the upper Rhine Graben to 360(68) years within one day of measurement. Further samples of the investigated aquifer system are dated similarly in order to obtain the age information for a comprehensive hydrological study. The apparatus has the potential to measure 39Ar-concentrations on small samples down to less than 1 ccSTP of Argon, corresponding to about 100 ml of air, 2.5 l of water or 1 kg of ice. This opens up the way for a broader application of 39Ar as a tracer e.g. in oceanography or glaciology, where the sample sizes are typically limited to 10 l of water or 1 kg of ice respectively. [1] Loosli, H. H. (1983), A dating method with 39Ar, Earth and Planetary Science Letters, 63, 51-62. [2] P. Collon, W. Kutschera, and Z.-T. Lu. Tracing noble gas radionuclides in the environment. Annual Review of Nuclear and Particle Science, 54(1): 39-67, 2004. [3] W. Jiang et al., An atom counter for measuring 81Kr and 85Kr in environmental samples. Geochimica et Cosmochimica Acta, 91(0):1-6, 2012. [4] Jiang, W. et al. (2011), 39Ar detection at the 10-16 isotopic abundance level with Atom Trap Trace Analysis, Phys. Rev. Lett. 106, DOI: 10.1103/PhysRevLett.106.103001.

  12. Radiometric sounding system

    SciTech Connect

    Whiteman, C.D.; Anderson, G.A.; Alzheimer, J.M.; Shaw, W.J.

    1995-04-01

    Vertical profiles of solar and terrestrial radiative fluxes are key research needs for global climate change research. These fluxes are expected to change as radiatively active trace gases are emitted to the earth`s atmosphere as a consequence of energy production and industrial and other human activities. Models suggest that changes in the concentration of such gases will lead to radiative flux divergences that will produce global warming of the earth`s atmosphere. Direct measurements of the vertical variation of solar and terrestrial radiative fluxes that lead to these flux divergences have been largely unavailable because of the expense of making such measurements from airplanes. These measurements are needed to improve existing atmospheric radiative transfer models, especially under the cloudy conditions where the models have not been adequately tested. A tethered-balloon-borne Radiometric Sounding System has been developed at Pacific Northwest Laboratory to provide an inexpensive means of making routine vertical soundings of radiative fluxes in the earth`s atmospheric boundary layer to altitudes up to 1500 m above ground level. Such vertical soundings would supplement measurements being made from aircraft and towers. The key technical challenge in the design of the Radiometric Sounding System is to develop a means of keeping the radiometers horizontal while the balloon ascends and descends in a turbulent atmospheric environment. This problem has been addressed by stabilizing a triangular radiometer-carrying platform that is carried on the tetherline of a balloon sounding system. The platform, carried 30 m or more below the balloon to reduce the balloon`s effect on the radiometric measurements, is leveled by two automatic control loops that activate motors, gears and pulleys when the platform is off-level. The sensitivity of the automatic control loops to oscillatory motions of various frequencies and amplitudes can be adjusted using filters.

  13. Radiometric cloud imaging with an uncooled microbolometer thermal infrared camera.

    PubMed

    Shaw, Joseph; Nugent, Paul; Pust, Nathan; Thurairajah, Brentha; Mizutani, Kohei

    2005-07-25

    An uncooled microbolometer-array thermal infrared camera has been incorporated into a remote sensing system for radiometric sky imaging. The radiometric calibration is validated and improved through direct comparison with spectrally integrated data from the Atmospheric Emitted Radiance Interferometer (AERI). With the improved calibration, the Infrared Cloud Imager (ICI) system routinely obtains sky images with radiometric uncertainty less than 0.5 W/(m(2 )sr) for extended deployments in challenging field environments. We demonstrate the infrared cloud imaging technique with still and time-lapse imagery of clear and cloudy skies, including stratus, cirrus, and wave clouds. PMID:19498585

  14. A Review of LIDAR Radiometric Processing: From Ad Hoc Intensity Correction to Rigorous Radiometric Calibration

    PubMed Central

    Kashani, Alireza G.; Olsen, Michael J.; Parrish, Christopher E.; Wilson, Nicholas

    2015-01-01

    In addition to precise 3D coordinates, most light detection and ranging (LIDAR) systems also record “intensity”, loosely defined as the strength of the backscattered echo for each measured point. To date, LIDAR intensity data have proven beneficial in a wide range of applications because they are related to surface parameters, such as reflectance. While numerous procedures have been introduced in the scientific literature, and even commercial software, to enhance the utility of intensity data through a variety of “normalization”, “correction”, or “calibration” techniques, the current situation is complicated by a lack of standardization, as well as confusing, inconsistent use of terminology. In this paper, we first provide an overview of basic principles of LIDAR intensity measurements and applications utilizing intensity information from terrestrial, airborne topographic, and airborne bathymetric LIDAR. Next, we review effective parameters on intensity measurements, basic theory, and current intensity processing methods. We define terminology adopted from the most commonly-used conventions based on a review of current literature. Finally, we identify topics in need of further research. Ultimately, the presented information helps lay the foundation for future standards and specifications for LIDAR radiometric calibration. PMID:26561813

  15. A Review of LIDAR Radiometric Processing: From Ad Hoc Intensity Correction to Rigorous Radiometric Calibration.

    PubMed

    Kashani, Alireza G; Olsen, Michael J; Parrish, Christopher E; Wilson, Nicholas

    2015-01-01

    In addition to precise 3D coordinates, most light detection and ranging (LIDAR) systems also record "intensity", loosely defined as the strength of the backscattered echo for each measured point. To date, LIDAR intensity data have proven beneficial in a wide range of applications because they are related to surface parameters, such as reflectance. While numerous procedures have been introduced in the scientific literature, and even commercial software, to enhance the utility of intensity data through a variety of "normalization", "correction", or "calibration" techniques, the current situation is complicated by a lack of standardization, as well as confusing, inconsistent use of terminology. In this paper, we first provide an overview of basic principles of LIDAR intensity measurements and applications utilizing intensity information from terrestrial, airborne topographic, and airborne bathymetric LIDAR. Next, we review effective parameters on intensity measurements, basic theory, and current intensity processing methods. We define terminology adopted from the most commonly-used conventions based on a review of current literature. Finally, we identify topics in need of further research. Ultimately, the presented information helps lay the foundation for future standards and specifications for LIDAR radiometric calibration. PMID:26561813

  16. Dating human skeletal remains using 90Sr and 210Pb: case studies.

    PubMed

    Schrag, Bettina; Uldin, Tanya; Mangin, Patrice; Bochud, François; Froidevaux, Pascal

    2014-01-01

    In legal medicine, the post mortem interval (PMI) of interest covers the last 50 years. When only human skeletal remains are found, determining the PMI currently relies mostly on the experience of the forensic anthropologist, with few techniques available to help. Recently, several radiometric methods have been proposed to reveal PMI. For instance, (14)C and (90)Sr bomb pulse dating covers the last 60 years and give reliable PMI when teeth or bones are available. (232)Th series dating has also been proposed but requires a large amount of bones. In addition, (210)Pb dating is promising but is submitted to diagenesis and individual habits like smoking that must be handled carefully. Here we determine PMI on 29 cases of forensic interest using (90)Sr bomb pulse. In 12 cases, (210)Pb dating was added to narrow the PMI interval. In addition, anthropological investigations were carried out on 15 cases to confront anthropological expertise to the radiometric method. Results show that 10 of the 29 cases can be discarded as having no forensic interest (PMI>50 years) based only on the (90)Sr bomb pulse dating. For 10 other cases, the additional (210)Pb dating restricts the PMI uncertainty to a few years. In 15 cases, anthropological investigations corroborate the radiometric PMI. This study also shows that diagenesis and inter-individual difference in radionuclide uptake represent the main sources of uncertainty in the PMI determination using radiometric methods. PMID:24287304

  17. [Laser-based radiometric calibration].

    PubMed

    Li, Zhi-gang; Zheng, Yu-quan

    2014-12-01

    Increasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physics, quantitative spectroscopy, etc. Internationally a number of national metrology scientific research institutes have built tunable laser based spectral radiometric calibration facilities in succession, which are traceable to cryogenic radiometers and have low uncertainties for spectral responsivity calibration and characterization of detectors and remote sensing instruments in the UK, the USA, Germany, etc. Among them, the facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCCUS) at the National Institute of Standards and Technology (NIST) in the USA and the Tunable Lasers in Photometry (TULIP) facility at the Physikalisch-Technische Bundesanstalt (PTB) in Germany have more representatives. Compared with lamp-monochromator systems, laser based spectral radiometric calibrations have many advantages, such as narrow spectral bandwidth, high wavelength accuracy, low calibration uncertainty and so on for radiometric calibration applications. In this paper, the development of laser-based spectral radiometric calibration and structures and performances of laser-based radiometric calibration facilities represented by the National Physical Laboratory (NPL) in the UK, NIST and PTB are presented, technical advantages of laser-based spectral radiometric calibration are analyzed, and applications of this technology are further discussed. Laser-based spectral radiometric calibration facilities can be widely used in important system-level radiometric calibration measurements with high accuracy, including radiance temperature, radiance and irradiance calibrations for space remote sensing instruments, and promote the development of aerospace, atmospheric physics, spectroscopy, biological science and so on in the fields of research and industry. PMID:25881452

  18. Application of the 40Ar/39Ar technique to date the Minoan Tuff, Santorini

    NASA Astrophysics Data System (ADS)

    Wijbrans, J. R.; Kuiper, K.; Morgan, L. E.; Klaver, M.; Vroon, P. Z.

    2012-12-01

    The age of the catastrophic eruption of the volcano of Santorini during the Bronze Age is well established from 14C dating at 3344.9 ± 7.5 a1 (uncertainties quoted as 1-σ). Application of the 40Ar/39Ar technique to products from this eruption is used here to (1) investigate the limits of the technique using conventional single collector mass spectrometry on a MAP215-50 instrument, (2) analyse sources of uncertainty to identify major contributing factors for the uncertainty of young 40Ar/39Ar ages, and (3) provide 40Ar/39Ar ages for a sample that has been previously dated via 14C and dendrochronology to further investigate issues with the accuracy of 40Ar/39Ar dating in the late Quaternary. We have separated the plagioclase fraction from the lower Minoan Tuff that immediately overlies the Cape Riva (rp6) tuff in a bay on the west coast of Thira, NW of the town of Oia. Using the calibration of 40Ar/36Ar of Lee et al.2, the decay constant recommended by Min at al.3, and the FCs age of Kuiper et al.4, we calculate an inverse isochron age of 3.7 ± 1.6 ka and a trapped 40Ar/36Ar intercept of 299.8 ± 1.2, slightly higher than the ratio for atmospheric argon of 298.56 ± 0.31, when all steps with ages > 50 ka are included in the regression. Enrichment in radiogenic 40Ar in the steps used for the isochron is extremely low, given the low concentration of K2O in plagioclase and the extremely young age. The stepwise heating approach proved useful because in all 5 replicate experiments unexpectedly high ages showed up at higher step temperatures, suggesting that in each separate some older contaminant was present. The plateaus of each of the replicate experiments had quite reproducible ages, however, and a pooled age was calculated for 23 out of 48 individual steps. The pooled age for the plateau was 17.6 ± 4.1 ka, which is high due to the slight component of excess 40Ar in the non-radiogenic component, as revealed from regression analysis. refs: 1SW Manning et al. (2006) Chronology for the Aegean Late Bronze Age 1700-1400 B.C., Science 312, 565 - 569. 2Lee J-Y, et al. (2006), A redetermination of the isotopic abundances of atmospheric Ar. Geochimica et Cosmochimica Acta 70, 4507-4512 3Min K, et al. (2001), Call for an improved set of decay constants for geochronological use. Geochimica et Cosmochimica Acta 65, 111 - 121. 4Kuiper et al. (2008), Synchronizing rock clocks of Earth History. Science 320, 500 - 504.

  19. Deep Springs fault, Inyo County, California: An example of the use of relative-dating techniques

    SciTech Connect

    Bryant, W.A.

    1989-11-01

    This article summarizes faulting in the Deep Springs Valley area, which was studied as part of a systematic evaluation of potentially active faults throughout California by the Division of Mines and Geology. Evaluation of surface fault-rupture hazard is authorized by the Alquist-Priolo Special Studies Zones Act of 1972. This act requires the State Geologist to delineate regulatory zones for faults that are well defined and show that displacement occurred during the last 11,000 years. Fault evaluations for the Division of Mines and Geology Fault Evaluation and Zoning Project are conducted at a detailed reconnaissance level. Evaluations are mainly based on aerial photographic interpretation in which ephemeral fault-produced landforms are identified and mapped. Young alluvial deposits and geomorphic surfaces are identified as either offset or not offset by faults. Field mapping is conducted to verify fault-related geomorphic features and to estimate ages of faulted and unfaulted deposits. The section on scarp degradation and relative dating techniques provides a brief survey of methods used in studies of the Basin and Range province. In these investigations geomorphic evidence is applied to determine the recency of faulting.

  20. Young Inclusions in an Old Host: Dating Alteration Events With Electron-Beam Techniques

    NASA Astrophysics Data System (ADS)

    Hetherington, C. J.; Jercinovic, M. J.; Roberts, R. J.

    2006-05-01

    A basic premise in deciphering the history of a rock is that textures such as mineral zoning, fold interference patterns, and unconformities establish a relative time line for an outcrop. A similar argument can be applied to poikiloblastic minerals, which provide information on pre-metamorphic mineral assemblages, a rock's P-T path, and, in cases where the inclusions are good chronometers, a P-T-t path. The focus of this study are zircons from an alkaline complex in the Seiland Igneous Province (Northern Norway) that presented several technical challenges during ID-TIMS analyses owing to the presence of xenotime and thorite mineral inclusions. These zircons also display irregular trace element distribution, localised internal porosity, and crystal face embayment. Careful selection of inclusion-free grains allowed the bracketing of alkaline magmatism to between 570 and 560 Ma. Discordant zircon grains give similar upper intercept ages, whilst the lower intercepts scatter widely ( 150) around 400 Ma. The data has been used to argue that there was only one demonstrable metamorphic event post-dating magmatism in the Seiland Igneous Province, corresponding to the Scandian phase of the Caledonian Orogeny. However, from the ID-TIMS analysis alone, this conclusion is not definitive; older Pb-loss events may be masked by Scandian metamorphism. The textural features of the zircon are diagnostic of dissolution-reprecipitation processes; a complex fluid-rock interaction commonly resulting in volume changes, porosity, replacement textures, and growth of mineral inclusions, and would also result in Pb loss from the primary zircon. To test for a correlation between Pb loss, zircon alteration, regional metamorphism, and dissolution-reprecipitation, electron-probe chemical-dating techniques were applied to suitable mineral inclusions in the zircon. The data yield a clustering of ages around 420 Ma, with no evidence for an older inclusion assemblage. These results support the hypothesis established by ID-TIMS. It is also noted that the age of the inclusions is in conflict with a classical interpretation of the poikilitic texture that requires the inclusions be coeval or older than the host zircon.

  1. The dating of shallow faults in the Earth's crust.

    PubMed

    van der Pluijm, B A; Hall, C M; Vrolijk, P J; Pevear, D R; Covey, M C

    2001-07-12

    Direct dating of ductile shear zones and calculation of uplift/exhumation rates can be done using various radiometric dating techniques. But radiometric dating of shallow crustal faulting, which occurs in the crust's brittle regime, has remained difficult because the low temperatures typical of shallow crusted faults prevent the complete syntectonic mineral recrystallization that occurs in deeper faults. Both old (detrital) and newly grown (authigenic) fine-grained phyllosilicates are thus preserved in shallow fault zones and therefore their radiometric ages reflect a mixture of both mineral populations. Also, the loss of 39Ar during neutron irradiation in dating of clay minerals can produce erroneously old ages. Here we present a method of characterizing the clay populations in fault gouge, using X-ray modelling, combined with sample encapsulation, and show how it can be used to date near-surface fault activity reliably. We examine fault gouge from the Lewis thrust of the southern Canadian Rockies, which we determine to be approximately 52 Myr old. This result requires the western North America stress regime to have changed from contraction to extension in only a few million years during the Eocene. We also estimate the uplift/exhumation age and sedimentary source of these rocks to be approximately 172 Myr. PMID:11449270

  2. Radiometric correction and calibration of SAR images

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony; Curlander, John C.

    1989-01-01

    A technique for producing radiometrically calibrated SAR image products is described. The output imagery is corrected to represent a measurement of the ground reflectivity or radar cross section. The sources of calibration errors are discussed and the appropriate forms of the radar equation as applied to SAR-image data are reviewed. A key result is the radar equation dependence on the azimuth reference function used in processing. A radiometric correction algorithm for use in an operational SAR correlator is presented. This algorithm has the characteristic that it is fully reversible. Additionally, it can be applied equally to detected or complex SAR images, and it allows for the subtraction of the estimated noise floor in the image but does not require this procedure.

  3. Investigation of the irradiation history of the Iranian dates and pistachio nuts using thermoluminescence technique

    NASA Astrophysics Data System (ADS)

    Sharifzadeh, M.; Sohrabpour, M.

    1993-07-01

    Three different varieties of Iranian fresh dates and five types of raw and salted pistachio nuts have been tested for identification of irradiation histories. Doses of 2.5, 5, 7.5 and 10 kGy from a gamma cell Gc-220 have been administrated to the samples under investigation. TL response versus dose for date and for pistachio nuts have been obtained. The effect of added ingredients such as salt in pistachio nuts, and moisture in date samples on the TL response have been studied. The fading of TL intensity of the irradiated dates and pistachio nuts have also been measured. Based on the latter results, it appears possible to identify the irradiated dates (10 kGy), within (1-2) months post-irradiation. In the salted pistachio nuts, the salt itself gives a very significant and distinguishable response. In the unsalted case, however, the difference between the irradiated and unirradiated samples seem difficult to detect due to partial overlapping of the respective responses.

  4. Uncooled radiometric camera performance

    NASA Astrophysics Data System (ADS)

    Meyer, Bill; Hoelter, T.

    1998-07-01

    Thermal imaging equipment utilizing microbolometer detectors operating at room temperature has found widespread acceptance in both military and commercial applications. Uncooled camera products are becoming effective solutions to applications currently using traditional, photonic infrared sensors. The reduced power consumption and decreased mechanical complexity offered by uncooled cameras have realized highly reliable, low-cost, hand-held instruments. Initially these instruments displayed only relative temperature differences which limited their usefulness in applications such as Thermography. Radiometrically calibrated microbolometer instruments are now available. The ExplorIR Thermography camera leverages the technology developed for Raytheon Systems Company's first production microbolometer imaging camera, the Sentinel. The ExplorIR camera has a demonstrated temperature measurement accuracy of 4 degrees Celsius or 4% of the measured value (whichever is greater) over scene temperatures ranges of minus 20 degrees Celsius to 300 degrees Celsius (minus 20 degrees Celsius to 900 degrees Celsius for extended range models) and camera environmental temperatures of minus 10 degrees Celsius to 40 degrees Celsius. Direct temperature measurement with high resolution video imaging creates some unique challenges when using uncooled detectors. A temperature controlled, field-of-view limiting aperture (cold shield) is not typically included in the small volume dewars used for uncooled detector packages. The lack of a field-of-view shield allows a significant amount of extraneous radiation from the dewar walls and lens body to affect the sensor operation. In addition, the transmission of the Germanium lens elements is a function of ambient temperature. The ExplorIR camera design compensates for these environmental effects while maintaining the accuracy and dynamic range required by today's predictive maintenance and condition monitoring markets.

  5. Landsat-5 TM reflective-band absolute radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Helder, D.L.; Markham, B.L.; Dewald, J.D.; Kaita, E.; Thome, K.J.; Micijevic, E.; Ruggles, T.A.

    2004-01-01

    The Landsat-5 Thematic Mapper (TM) sensor provides the longest running continuous dataset of moderate spatial resolution remote sensing imagery, dating back to its launch in March 1984. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset of each detector. Due to observed degradations in the IC, a new procedure was implemented for U.S.-processed data in May 2003. This new calibration procedure is based on a lifetime radiometric calibration model for the instrument's reflective bands (1-5 and 7) and is derived, in part, from the IC response without the related degradation effects and is tied to the cross calibration with the Landsat-7 Enhanced Thematic Mapper Plus. Reflective-band absolute radiometric accuracy of the instrument tends to be on the order of 7% to 10%, based on a variety of calibration methods.

  6. Radiometric Study of Soil Profiles in the Infrared Band

    NASA Astrophysics Data System (ADS)

    Ponomareva, T. V.; Ponomarev, E. I.

    2016-02-01

    The applicability of radiometric survey of soil profiles in the infrared range for the analysis of soil physical properties was studied. Radiometric data were obtained for different dates of the growing season for a number of soil profiles. The specificity of temperature profiles of texture-differentiated soils (Luvisols and Retisols) as related to weather conditions of the growing season was examined. The correlation analysis showed a close relationship between the air and surface soil temperatures and between the radiometric and thermodynamic soil temperatures in the upper 10 cm. In the studied profiles, the gradient of radiometric temperatures reached 0.5-0.8°C/cm in the humus horizons and sharply decreased at the depth of more than 15-20 cm. The gradient analysis of radiometric images made it possible to outline the boundaries of soil horizons. For the texture-differentiated soils, the most distinct boundaries were established between the gray-humus AY horizon and the underlying eluvial EL horizon in podzolic soils and between the AY horizon and the underlying humus-eluvial AEL horizon in gray soils.

  7. Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating.

    SciTech Connect

    Andrews, A H; Kerr, L A; Cailliet, G M; Brown, T A; Lundstrom, C C; Stanley, R D

    2007-11-04

    Canary rockfish (Sebastes pinniger) have long been an important part of recreational and commercial rockfish fishing from southeast Alaska to southern California, but localized stock abundances have declined considerably. Based on age estimates from otoliths and other structures, lifespan estimates vary from about 20 years to over 80 years. For the purpose of monitoring stocks, age composition is routinely estimated by counting growth zones in otoliths; however, age estimation procedures and lifespan estimates remain largely unvalidated. Typical age validation techniques have limited application for canary rockfish because they are deep dwelling and may be long lived. In this study, the unaged otolith of the pair from fish aged at the Department of Fisheries and Oceans Canada was used in one of two age validation techniques: (1) lead-radium dating and (2) bomb radiocarbon ({sup 14}C) dating. Age estimate accuracy and the validity of age estimation procedures were validated based on the results from each technique. Lead-radium dating proved successful in determining a minimum estimate of lifespan was 53 years and provided support for age estimation procedures up to about 50-60 years. These findings were further supported by {Delta}{sup 14}C data, which indicated a minimum estimate of lifespan was 44 {+-} 3 years. Both techniques validate, to differing degrees, age estimation procedures and provide support for inferring that canary rockfish can live more than 80 years.

  8. Identifying and Dating Metamorphic Zircons in Clastic Rocks and River Sediments and the Technique of U-Pb Dating Fine Overgrowths

    NASA Astrophysics Data System (ADS)

    Allen, C. M.; Campbell, I. H.

    2004-05-01

    Unique identification of metamorphic zircon in river sands and clastic rocks using any of composition, morphology or internal structure is difficult but in two situations we can confidently identify zircon associated with metamorphism: discrete overgrowths on older cores, and wide zones of Pb loss (diffusion). The former may be associated with partial melting but marks the age and culmination of metamorphism. Routine U-Th-Pb dating and analysis of low abundance trace elements of thin zircon overgrowths was unavailable until our laser rim-piercing technique was developed at ANU where we have an Excimer laser (193 nm wavelength; long focal length) attached to an Agilent 7500S Q-ICP-MS. We fasten HCl-washed but otherwise unprepared zircons onto adhesive tape and in a sample chamber carrying He+Ar we ablate 32 micron wide holes about 25 micron deep into the zircon. The ablated material is carried into the ICP. The impact of the technique is clear from an example of the Ganges River sand. If mounted in the traditional way with zircons embedded in epoxy and polished to expose cores, and using a shallow spot U-Pb dating method, knowledge of the significant adjacent Himalayan orogeny could only ensue if dozens to hundreds of analyses were undertaken and discordia were constructed from many grains. Discordia must be fit to those grains with the same inherited age, a challenge for a river sand sample. Using the rim-piercing technique gives us indication of the Himalayan event in about 5 to 10 percent of all analysed grains. In 60 seconds, a metamorphic rim, Pb loss region, and inherited core can be analysed. If the rim is wider than 5 microns a precise age can be measured. Moreover, even if the rim is not preserved, and the core not encountered, the Pb loss zone if wide enough (~15 mcirons) can be used to construct a discordia on that single grain with moderately precise lower and upper intercept ages. In several zircons from sediments drained from high-grade metamorphic terranes, we have encountered zones where 206Pb/238U changes continuously over 25 microns while the 207Pb/206Pb remains constant. This result strongly suggests Pb diffusion over broad areas in high-grade metamorphic zircons that do not appear metamict.

  9. Irradiation for dating Brazilian fish fossil by thermoluminescence and EPR technique

    NASA Astrophysics Data System (ADS)

    Sullasi, H. S.; Andrade, M. B.; Ayta, W. E. F.; Frade, M.; Sastry, M. D.; Watanabe, S.

    2004-01-01

    Fish fossil from Ceara State, Brazil has been investigated using thermoluminescence and EPR method. In both cases, additive method has been used by irradiating fossil samples to very high doses (tens of kGy). In the case of thermoluminescence, 360 °C peak was used for dating. Since the fish fossil contains relatively high concentration of Mn, the EPR Mn 2+-lines cover carbonate and sulfate radicals signal (sulfur is also present in large amount), therefore 50 mW microwave power was used for EPR measurements. At this high power region Mn 2+-lines become very little intense and SO 2- and CO 2- can be detected. Both TL and EPR dating presented an age around 8 Ma. Correction due to spontaneous decay of 360 °C peak at ambient temperature gives rise to about ˜24 Ma of age.

  10. Landsat-8 Operational Land Imager Radiometric Calibration and Stability

    NASA Technical Reports Server (NTRS)

    Markham, Brian; Barsi, Julia; Kvaran, Geir; Ong, Lawrence; Kaita, Edward; Biggar, Stuart; Czapla-Myers, Jeffrey; Mishra, Nischal; Helder, Dennis

    2014-01-01

    The Landsat-8 Operational Land Imager (OLI) was radiometrically calibrated prior to launch in terms of spectral radiance, using an integrating sphere source traceable to National Institute of Standards and Technology (NIST) standards of spectral irradiance. It was calibrated on-orbit in terms of reflectance using diffusers characterized prior to launch using NIST traceable standards. The radiance calibration was performed with an uncertainty of (is) approximately 3%; the reflectance calibration to an uncertainty of approximately 2%. On-orbit, multiple calibration techniques indicate that the sensor has been stable to better than 0.3% to date, with the exception of the shortest wavelength band, which has degraded about 1.0%. A transfer to orbit experiment conducted using the OLI's heliostat-illuminated diffuser suggests that some bands increased in sensitivity on transition to orbit by as much as 5%, with an uncertainty of approximately 2.5%. On-orbit comparisons to other instruments and vicarious calibration techniques show the radiance (without a transfer to orbit adjustment), and reflectance calibrations generally agree with other instruments and ground measurements to within the uncertainties. Calibration coefficients are provided with the data products to convert to either radiance or reflectance units.

  11. Testing the Cambrian explosion hypothesis by using a molecular dating technique.

    PubMed

    Bromham, L; Rambaut, A; Fortey, R; Cooper, A; Penny, D

    1998-10-13

    Molecular studies have the potential to shed light on the origin of the animal phyla by providing independent estimates of the divergence times, but have been criticized for failing to account adequately for variation in rate of evolution. A method of dating divergence times from molecular data addresses the criticisms of earlier studies and provides more realistic, but wider, confidence intervals. The data are not compatible with the Cambrian explosion hypothesis as an explanation for the origin of metazoan phyla, and provide additional support for an extended period of Precambrian metazoan diversification. PMID:9770496

  12. A new technique for precise uranium-series dating of travertine micro-samples

    NASA Astrophysics Data System (ADS)

    Mallick, Ronzon; Frank, Norbert

    2002-12-01

    Secondary carbonate formations, such as travertine and calcareous tufa deposits, are important archives for quaternary continental climate studies and archaeology. The extremely complex growth mechanisms result in some serious problems for precise mass spectrometric uranium-series dating. Often, detrital and organic particles contaminate the carbonate and large pore volumes yield a great potential for open system behavior. We utilized microscopic, mineralogical and geochemical methods prior to sample selection to determine the abundance of primary calcite, i.e. micrite and spar. Furthermore, the state of alteration was characterized by cathodoluminescence and trace-element analysis. We conclude that travertine and calcareous tufa are appropriate for precise U-series age determination if a) micrite and/or spar are the dominant phases; b) cathodoluminescence of both phases is weak or absent; c) Fe and Al levels are low; and d) Sr concentrations are close to the average of the studied site. We mapped and sampled solely areas of major micrite/spar abundance having minor alteration for accurate U-series dating. When this new method was applied, travertines located in eastern Germany (sites Bad Langensalza, Burgtonna and Weimar-Ehringsdorf) gave single 230Th/ 238U-ages consistent with the lithological growth sequence and greatly improved compared to previously published chronologies. In addition, we determined 230Th/U isochron ages on bulk samples that confirm our single ages. In contrast to primary calcite, pore cements are homogeneously distributed throughout the travertine fabric and reflect early diagenetic processes and/or weathering.

  13. Up-to-date state of storage techniques used for large numerical data files

    NASA Technical Reports Server (NTRS)

    Chlouba, V.

    1975-01-01

    Methods for data storage and output in data banks and memory files are discussed along with a survey of equipment available for this. Topics discussed include magnetic tapes, magnetic disks, Terabit magnetic tape memory, Unicon 690 laser memory, IBM 1360 photostore, microfilm recording equipment, holographic recording, film readers, optical character readers, digital data storage techniques, and photographic recording. The individual types of equipment are summarized in tables giving the basic technical parameters.

  14. Correction function in the Lidar equation and the solution techniques for CO2 Lidar date reduction

    NASA Technical Reports Server (NTRS)

    Zhao, Y.; Lea, T. K.; Schotland, R. M.

    1986-01-01

    For lidar systems with long laser pulses the unusual behavior of the near-range signals causes serious difficulties and large errors in reduction. The commonly used lidar equation is no longer applicable since the convolution of the laser pulse with the atmospheric parameter distributions should be taken into account. It is important to give more insight into this problem and find the solution techniques. Starting from the original equation, a general form is suggested for the single scattering lidar equation where a correction function Cr is introduced. The correction Function Cr(R) derived from the original equation indicates the departure from the normal lidar equation. Examples of Cr(R) for a coaxial CO2 lidar system are presented. The Differential Absorption Lidar (DIAL) errors caused by the differences of Cr(R) for H2O measurements are plotted against height.

  15. JACIE Radiometric Assessment of QuickBird Multispectral Imagery

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Carver, David; Holekamp, Kara; Knowlton, Kelly; Ryan, Robert; Zanoni, Vicki; Thome, Kurtis; Aaron, David

    2004-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can place confidence in the imagery they use and can fully understand its properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, the NASA Stennis Space Center (SSC) Earth Science Applications (ESA) directorate,through the Joint Agency for Commercial Imagery Evaluation (JACIE) framework, established a commercial imaging satellite radiometric calibration team consisting of two groups: 1) NASA SSC ESA, supported by South Dakota State University, and 2) the University of Arizona Remote Sensing Group. The two groups determined the absolute radiometric calibration coefficients of the Digital Globe 4-band, 2.4-m QuickBird multispectral product covering the visible through near-infrared spectral region. For a 2-year period beginning in 2002, both groups employed some variant of a reflectance-based vicarious calibration approach, which required ground-based measurements coincident with QuickBird image acquisitions and radiative transfer calculations. The groups chose several study sites throughout the United States that covered nearly the entire dynamic range of the QuickBird sensor. QuickBird at-sensor radiance values were compared with those estimated by the two independent groups to determine the QuickBird sensor's radiometric accuracy. Approximately 20 at-sensor radiance estimates were vicariously determined each year. The estimates were combined to provide a high-precision radiometric gain calibration coefficient. The results of this evaluation provide the user community with an independent assessment of the QuickBird sensor's absolute calibration and stability over the 2-year period. While the techniques and method described reflect those developed at the NASA SSC, the results of both JACIE team groups are included in this paper.

  16. Radiometrically accurate scene-based nonuniformity correction for array sensors

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Hayat, Majeed M.; Tyo, J. Scott

    2003-10-01

    A novel radiometrically accurate scene-based nonuniformity correction (NUC) algorithm is described. The technique combines absolute calibration with a recently reported algebraic scene-based NUC algorithm. The technique is based on the following principle: First, detectors that are along the perimeter of the focal-plane array are absolutely calibrated; then the calibration is transported to the remaining uncalibrated interior detectors through the application of the algebraic scene-based algorithm, which utilizes pairs of image frames exhibiting arbitrary global motion. The key advantage of this technique is that it can obtain radiometric accuracy during NUC without disrupting camera operation. Accurate estimates of the bias nonuniformity can be achieved with relatively few frames, which can be fewer than ten frame pairs. Advantages of this technique are discussed, and a thorough performance analysis is presented with use of simulated and real infrared imagery.

  17. Absolute Dating of Middle Pleistocene Palaeontological Records from the Guadix-Baza Basin, Spain, Using Extended-range OSL Dating Techniques

    NASA Astrophysics Data System (ADS)

    Demuro, M.; Arnold, L. J.; Pares, J. M.

    2012-12-01

    The Guadix-Baza basin, southern Spain, contains an important archive of palustrine/lacustrine records covering the late Miocene to Middle Pleistocene. Numerous palaentological sites have been described within the Guadix-Baza basin, which record faunal and climatic changes spanning the Early to Middle Pleistocene, and contain some of the earliest evidence of human presence in Europe. Chronological control for these palustrine/lacustrine sequences has been achieved via a combination of relative dating methods, such as stratigraphic correlations, palaeomagnatism and biochronology. However, in spite of the large number of research undertaken over the past 20 years, absolute chronological control is still lacking for these sites due to (i) the antiquity of the deposits, which precludes the use of radiocarbon and conventional optically stimulated luminescence (OSL) dating, and (ii) the lack of datable material for long-ranging methods, such as Ar/Ar on tephras or U-series. Conventional OSL dating of quartz is now routinely applied to sedimentary deposits that are less than 200 ka old, but it is not generally suitable for older deposits owing to saturation of the OSL signal. Over the past 10 years, a series of extended range OSL methodologies have been proposed for dating Middle Pleistocene deposits, which make use of luminescence signals with higher saturation limits. Here we report on chronologies obtained using so-called thermally-transferred (TT) OSL dating and post-IR IRSL feldspar dating of Early/Middle Pleistocene deposits from the Baza sub-basin. In total, 5 samples were collected from deposits bracketing the main palaeontological/archaeological horizons at two sites (Huescar-1 and Cullar de Baza-1). Single-grain OSL was also applied to the youngest samples to obtain additional chronologies for comparison with the multi-grain TT-OSL and post-IR IRSL ages. The suitability of the TT-OSL and post-IR IRSL signals for dating these deposits is tested via a series of quality assurance criteria (signal composition, dose recovery tests, bleaching tests, sensitivity correction assessments). The resultant extended-age OSL chronologies are presented and used to assess (i) the accuracy of existing chronostratigraphic frameworks developed at these sites, and (ii) the wider applicability of these novel dating approaches for constraining early human presence in Europe.

  18. Absolute dating of Middle Pleistocene palaeontological records from the Guadix-Baza basin, Spain, using extended-range OSL dating techniques

    NASA Astrophysics Data System (ADS)

    Demuro, Martina; Arnold, Lee; Pares, Josep

    2013-04-01

    The Guadix-Baza basin, southern Spain, contains an important archive of palustrine/lacustrine records covering the late Miocene to Middle Pleistocene. Numerous palaentological sites have been described within the Guadix-Baza basin, which record faunal and climatic changes spanning the Early to Middle Pleistocene, and contain some of the earliest evidence of human presence in Europe. Chronological control for these palustrine/lacustrine sequences has been achieved via a combination of relative dating methods, such as stratigraphic correlations, palaeomagnatism and biochronology. However, in spite of the large number of research undertaken over the past 20 years, absolute chronological control is still lacking for these sites due to (i) the antiquity of the deposits, which precludes the use of radiocarbon and conventional optically stimulated luminescence (OSL) dating, and (ii) the lack of datable material for long-ranging methods, such as Ar/Ar on tephras or U-series. Conventional OSL dating of quartz is now routinely applied to sedimentary deposits that are less than 200 ka old, but it is not generally suitable for older deposits owing to saturation of the OSL signal. Over the past 10 years, a series of extended range OSL methodologies have been proposed for dating Middle Pleistocene deposits, which make use of luminescence signals with higher saturation limits. Here we report on chronologies obtained using so-called thermally-transferred (TT) OSL dating and post-IR IRSL feldspar dating of Middle Pleistocene deposits from the Baza sub-basin. In total, 5 samples were collected from deposits bracketing the main palaeontological/archaeological horizons at two sites (Huescar-1 and Cullar de Baza-1). Single-grain OSL was also applied to the youngest samples to obtain additional chronologies for comparison with the multi-grain TT-OSL and post-IR IRSL ages. The suitability of the TT-OSL and post-IR IRSL signals for dating these deposits is tested via a series of quality assurance criteria (signal composition, dose recovery tests, bleaching tests, sensitivity correction assessments). The resultant extended-age OSL chronologies are presented and used to assess (i) the accuracy of existing chronostratigraphic frameworks developed at these sites, and (ii) the wider applicability of these novel dating approaches for constraining early human presence in Europe.

  19. Geochemistry and radiometric dating of a Middle Pleistocene peat

    SciTech Connect

    Rowe, P.J.; Atkinson, T.C.; Richards, D.A.; Bottrell, S.H.; Cliff, R.A.

    1997-10-01

    Uranium, lead, and sulphur data for a Middle Pleistocene interglacial peat deposit from Norfolk, UK, suggest that uptake of these elements was synchronous and confined to a single early diagenetic episode, probably coeval with peat formation. Sulphur isotope data indicate that reducing conditions have been maintained within the deposit throughout its history. Both uranium and lead concentration profiles show a marked discontinuity near the middle of the bed, probably indicating an environmental change, possibly emergence. The lead isotope data are compatible with a single lead component below the discontinuity and two components above. Groundwater is thought to be the dominant source of lead with an additional airfall component present in the upper peat. The uranium and lead concentration profiles below the discontinuity and the sulfur isotope profile throughout the peat support the view that these elements were sequestered from upwelling groundwaters. 35 refs., 9 figs., 3 tabs.

  20. Influence of Lossy Compressed DEM on Radiometric Correction for Land Cover Classification of Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Moré, G.; Pesquer, L.; Blanes, I.; Serra-Sagristà, J.; Pons, X.

    2012-12-01

    World coverage Digital Elevation Models (DEM) have progressively increased their spatial resolution (e.g., ETOPO, SRTM, or Aster GDEM) and, consequently, their storage requirements. On the other hand, lossy data compression facilitates accessing, sharing and transmitting large spatial datasets in environments with limited storage. However, since lossy compression modifies the original information, rigorous studies are needed to understand its effects and consequences. The present work analyzes the influence of DEM quality -modified by lossy compression-, on the radiometric correction of remote sensing imagery, and the eventual propagation of the uncertainty in the resulting land cover classification. Radiometric correction is usually composed of two parts: atmospheric correction and topographical correction. For topographical correction, DEM provides the altimetry information that allows modeling the incidence radiation on terrain surface (cast shadows, self shadows, etc). To quantify the effects of the DEM lossy compression on the radiometric correction, we use radiometrically corrected images for classification purposes, and compare the accuracy of two standard coding techniques for a wide range of compression ratios. The DEM has been obtained by resampling the DEM v.2 of Catalonia (ICC), originally having 15 m resolution, to the Landsat TM resolution. The Aster DEM has been used to fill the gaps beyond the administrative limits of Catalonia. The DEM has been lossy compressed with two coding standards at compression ratios 5:1, 10:1, 20:1, 100:1 and 200:1. The employed coding standards have been JPEG2000 and CCSDS-IDC; the former is an international ISO/ITU-T standard for almost any type of images, while the latter is a recommendation of the CCSDS consortium for mono-component remote sensing images. Both techniques are wavelet-based followed by an entropy-coding stage. Also, for large compression ratios, both techniques need a post processing for correctly delimiting coastline, avoiding the confusion between elevation and no-data values. Six (from March 2005 to May 2007) geometrically corrected Landsat-5 images on the path-row 197-031 have been used. The six optical bands and the NDVI for each date have been introduced in a powerful hybrid classification process. The training areas and the ground truth have been obtained from the Mapa de Cobertes del Sòl de Catalunya (v. 3), a land cover map created by photointerpretation of 0.5 m orthophotomaps acquired between 2005 and 2007 and covering all the extension of Catalonia. The legend has been reduced from 233 categories to 21. Preliminary results have shown that the effect on land cover classification of applying lossy compression to the DEM used in the radiometric correction is small (lower than 1%) even for compression ratios up to 200:1. Comparing classification performance after a compression of 5:1 and and a compression of 200:1 with both coding standards showed that: a) the percentage of correctly classified image was 73%; b) 20% was wrongly classified; c) 3.5% was wrongly classified at compression ratio 5:1; and d) also 3.5% was wrongly classified at compression ratio 200:1. These results are the first in the literature to analyze the effect of DEM lossy compressing when DEM are employed for radiometric correction.

  1. A comparison of rating and dating techniques to estimate the threat of soil erosion to archaeological monuments under agricultural fields

    NASA Astrophysics Data System (ADS)

    van Soest, Maud; Huisman, Hans; Schoorl, Jeroen; Reimann, Tony; Temme, Arnaud; Wallinga, Jakob; de Kort, Jan-Willem; van der Heiden, Menno; van Os, Bertil; van Egmond, Fenny; Ketteren, Michael

    2015-04-01

    For the protection of Dutch archaeological sites against degradation, the TOPsites project is investigating the rate, extent and mitigation of the most important processes involved. One of these processes is soil translocation or soil redistribution. For many Dutch archaeological sites the actual extent and rate of soil erosion is not yet known. In this study different techniques for dating and estimating rates have been compared on three archaeological sites on tilled fields with gentle slopes: (multi-temporal LiDar, profiles and spatial distribution of 137Cs, anthropogenic Pb, and 239+240Pu, and moreover OSL. In addition, the added value of the combination of several of these techniques together will be evaluated. Preliminary results show evidence for colluvium formation (deposition) on two of the sites. Lead contents in a buried soil on one of these sites suggest a subrecent to recent date. 137Cs profiles and spatial mapping, however, do not show clear evidence for recent erosion or re-deposition patterns. These first results suggest that in these agricultural settings with typical Dutch gentle slopes, erosion may only occur in rare, catastrophic, events with local high erosion and re-deposition rates instead of a more or less continuous process with lower rates. Consequently, the impact of ploughing might be limited to mixing of the plough layer, while the effect of damaging soil translocation, for these selected archaeological sites, seems less important. Forthcoming analysis and results of Pu and OSL will provide enough data for further discussion and possible falsification of these preliminary conclusions.

  2. Modeling radiometric effects on airborne multispectral videography

    NASA Astrophysics Data System (ADS)

    Fischer, Robert L., Jr.

    Observing the Earth through remote technologies allows for the extraction of synoptic data that is difficult to match with ground-based measurements. Over time, remote sensing instruments and associated processing algorithms have improved in both spectral and spatial resolution. Currently, commercial spaceborne and airborne imaging systems are capable of producing data at one-meter spatial resolution. To fully utilize these improved data sources, it is critical that processing and analysis algorithms keep pace with instrument advances. This dissertation describes models and algorithms used to correct high spatial resolution airborne imagery for radiometric effects. These radiometric effects include topography and view-angle (also termed bidirectional reflectance). Also studied were radiometric and geometric calibration issues. The sensor used for this study was a four camera off-the-shelf system which is capable of collecting imagery in the visible through near-infrared (0.4-1.0 ?m) spectral region. Three topographic correction models were applied to one- meter spatial resolution imagery collected over Fort Huachuca, Arizona, in October 1998. The model proposed by Ekstrand (1996) was successful in reducing topographic effects found in the semidesert grassland and Madrean forest communities. Spectral signature coefficient of variation, histogram range, and histogram normality all showed improvement after correction for both classes. Additionally, the optimal spatial resolution of the supporting Digital Elevation Model (DEM) was found to be 40 meters. This disagrees with previous research stating that the imagery to be corrected and the supporting DEM should be the same spatial resolution. Two bidirectional reflectance models were applied to 1.5 meter spatial resolution imagery collected over Parramore Island, Virginia, in May 1999. A modified version of a model proposed by Irons et al. (1991) was found to substantially reduce bidirectional reflectance effects over four vegetation communities. Spectral signature coefficient of variation and overlap pixel difference showed improvement after correction. Additionally, an unsupervised technique was developed to generate training data for model coefficient generation. This technique produces a large amount of training points, is relatively free of user bias, and can be used as a masking procedure to apply the correction models to the appropriate land- cover classes. Finally, the computational aspects of mosaic construction and sensor orientation calculation were examined. A distributed approach for pass-point generation was developed utilizing off-the-shelf hardware and software. The use of six processors was found to improve performance by a factor of 5.2 (measured by calculation time) when compared to a single processor. Products developed as part of the computational process are discussed. These included orthomosaics, anaglyphs, and digital elevation models. The radiometric correction models studied should be extendable to any high spatial resolution (airborne or spaceborne) multispectral or hyperspectral system. The end-to-end processing routines developed as part of this study will substantially increase the data throughput of digital multispectral videography systems.

  3. Algorithm for radiometrically accurate nonuniformity correction with arbitrary scene motion

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Hayat, Majeed M.; Tyo, J. Scott

    2003-08-01

    This paper describes a major generalization of a recently reported radiometrically-accurate algebraic nonuniformity correction (NUC) algorithm. The original technique was capable of accurately estimating the bias nonuniformity from a sequence of pairs of images exhibiting strictly one-dimensional (1D) subpixel shifts. The new technique relaxes the subpixel 1D shift constraint to arbitrary two-dimensional (2D) motion, which can be either sub-pixel or super-pixel. The 2D technique relies on calibrating only rows and columns on the perimeter of the array, which in turn, provides the algorithm with the necessary initial conditions to recursively estimate the bias values in the entire array. In this way, radiometric NUC can be achieved non-disruptively, as needed, without disturbing the functionality of the interior array elements. The 2D algorithm is highly localized in time and space lending itself to near real-time implementation. Radiometric NUC can be achieved with a relatively low number of frames (typically about 10 frame pairs). Moreover, as in its earlier 1D version, the performance of the 2D algorithm is shown to be insensitive to spatial diversity in the scene. This paper will address the performance of the 2D technique using real infrared data.

  4. Direct Dating of Hominids Remains In Eurasia

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Falgures, C.

    When archaeological sites are associated with human remains, it is relevant to be able to date those valuable remains for different reasons. The main one is that it avoids the stratigraphical problems which can be due to intrusive burials in the sequence. The other reason consists in the fact that human bones may be encountered out of established stratigraphical context. On the other hand, the majority of dating methods currently used are destructive and can not be applied on these precious samples particularly when they are older than 40,000 years and can not be dated by radiocarbon. Since several years, we have developped a completely non-destructive method which consists in the measurement of human remains using the gamma -ray spectrometry. This technique has been used recently by other laboratories. We present here two important cases for the knowledge of human evolution in Eurasia. The first example is Qafzeh site in Israel where many human skeletons have been unearthed from burials associated with fauna and lithic artefacts. This site has been dated by several independent radiometric methods. So, it was possible to compare our gamma results with the other results yielded by the different methods. The second case concerns the most evolved Homo erectus found in Java, Indonesia, at Ngandong site, close to the Solo river. A recent debate has been focused on the age of these fossils and their direct dating is of outmost importance for the knowledge of settlement of Modern Humans in South-East Asia.

  5. Chemical Principles Revisited: Archaeological Dating.

    ERIC Educational Resources Information Center

    Rowe, M. W.

    1986-01-01

    Discusses methods used to date archaeological artifacts and other remains. They include: (1) nuclear dating techniques (radiocarbon dating, accelerator radiocarbon dating, thermoluminescence, and others); (2) chemical dating techniques (amino acid racemization, obsidian hydration dating, elemental content changes, and thermal analysis dating); and

  6. Chemical Principles Revisited: Archaeological Dating.

    ERIC Educational Resources Information Center

    Rowe, M. W.

    1986-01-01

    Discusses methods used to date archaeological artifacts and other remains. They include: (1) nuclear dating techniques (radiocarbon dating, accelerator radiocarbon dating, thermoluminescence, and others); (2) chemical dating techniques (amino acid racemization, obsidian hydration dating, elemental content changes, and thermal analysis dating); and…

  7. Small satellite radiometric measurement system

    SciTech Connect

    Weber, P.G.

    1992-01-01

    A critical need for the US Global Change Research Program is to provide continuous, well-calibrated radiometric data for the earth's radiation budget. This paper describes a new, compact, relatively light-weight, adaptable radiometer which will provide both spectrally integrated measurements and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted aircraft (RPAs). An example of the implementation of this radiometer on a small satellite is given. Significant benefits derive from simultaneous measurements of specific narrow (in wavelength) spectral features; such data may be obtained by combining LARI with a compact spectrometer on the same platform. Well-chosen satellite orbits allow one to use data from other satellites (e.g. DMSP) to enhance the data product, or to provide superior coverage of specific locations. 23 refs.

  8. Small satellite radiometric measurement system

    SciTech Connect

    Weber, P.G.

    1992-01-01

    A critical need for the US Global Change Research Program is to provide continuous, well-calibrated radiometric data for the earth`s radiation budget. This paper describes a new, compact, relatively light-weight, adaptable radiometer which will provide both spectrally integrated measurements and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted aircraft (RPAs). An example of the implementation of this radiometer on a small satellite is given. Significant benefits derive from simultaneous measurements of specific narrow (in wavelength) spectral features; such data may be obtained by combining LARI with a compact spectrometer on the same platform. Well-chosen satellite orbits allow one to use data from other satellites (e.g. DMSP) to enhance the data product, or to provide superior coverage of specific locations. 23 refs.

  9. Absolute Radiometric Calibration of SERTS

    NASA Astrophysics Data System (ADS)

    Thomas, R. J.; Condor, C. E.; Haas, J. P.; Linard, D. L., II; Swartz, M.; Kent, B. J.; Hollandt, J.

    1997-12-01

    The Solar EUV Rocket Telescope and Spectrograph (SERTS) obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. We have recently carried out a complete end-to-end calibration of the instrument to determine its absolute radiometric response over the full bandpass of 300 -- 365 Angstroms. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibration of the Coronal Diagnostic Spectrometer (CDS) experiment now flying aboard the SOHO spacecraft. For our SERTS project, the unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) in Germany was re-calibrated to an absolute accuracy of 7% (1sigma ) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is a primary radiometric source standard. Scans of the SERTS aperture over a range of pitch and yaw angles were made to determine the instrument's absolute spectral sensitivity to <= 25%, considering all sources of error. These results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted `insensitive' line ratios. The recent measurements at RAL also give information about the uniformity of illumination across the collimated source beam, as well as about polarization characteristics of both the instrument and radiation source, which may prove helpful in correctly interpreting the original CDS calibration data. We hope to repeat such calibration measurements and to provide future SERTS flights annually, at least throughout the duration of the SOHO mission. Coordinated observing programs would then allow these updated absolute calibrations to be transferred on a regular basis to several of the instruments onboard SOHO, including CDS, EIT, and CELIAS.

  10. Changes in the Radiometric Sensitivity of SeaWiFS

    NASA Technical Reports Server (NTRS)

    McClain, Charles R.; Barnes, Robert A.; Eplee, Robert E., Jr.; Patt, Frederick S.

    1998-01-01

    We report on the lunar and solar measurements used to determine the changes in the radiometric sensitivity of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Radiometric sensitivity is defined as the output from the instrument (or from one of the instrument bands) per unit spectral radiance at the instrument's input aperture. Knowledge of the long-term repeatability of the SeaWiFS measurements is crucial to maintaining the quality of the ocean scenes derived from measurements by the instrument. For SeaWiFS bands 1 through 6 (412 nm through 670 rim), the change in radiometric sensitivity is less than 0.2% for the period from November 1997 through November 1998. For band 7 (765 nm), the change is about 1.5%, and for band 8 (865 nm) about 5%. The rates of change of bands 7 and 8, which were linear with time for the first eight months of lunar measurements, are now slowing. The scatter in the data points about the trend lines in this analysis is less than 0.3% for all eight SeaWiFS bands. These results are based on monthly measurements of the moon. Daily solar measurements using an onboard diffuser show that the radiometric sensitivities of the SeaWiFS bands have changed smoothly during the time intervals between lunar measurements. Since SeaWiFS measurements have continued past November 1998, the results presented here are considered as a snapshot of the instrument performance as of that date.

  11. Precise prelaunch radiometric calibration of VIIRs

    NASA Astrophysics Data System (ADS)

    Mikheenko, Leonid; Borovytsky, Volodymyr; Hudz, Oleksii

    2015-09-01

    The paper presents the new approach that includes technique, scheme and instruments for precise calibration of space-borne and airborne visible infrared imaging radiometers (VIIRs). The key component of this technique is the precise uniform light source based on optically-interconnected integrating spheres. The light source contains several (5…11) primary integrating spheres of small diameters which are installed on a secondary integrating sphere of bigger diameter. The initial light sources - halogen lamps or light emitted diodes are installed inside the primary integrating spheres. These spheres are mounted on the secondary integrating sphere. The radiation comes from the primary integrating spheres to the secondary one through diaphragms which diameters can be varied. The secondary integrating sphere has an output aperture where uniform radiance emits. As a result the output radiance can be varied in extremely wide range - up to 800 W/(st·m2) with dynamic range 1 000 000 - without any change of spectral characteristics. Non-uniformity of the radiance distribution throughout the output aperture can be smaller 0.5 % because the secondary integrating sphere is illuminated uniformly and it does not contain lamps inside. The paper discusses the requirements to calibration system, the application of this light source in calibration procedures, metrological aspects of radiometric calibration.

  12. Calibration transfer target for a microwave radiometric profiling system

    NASA Astrophysics Data System (ADS)

    Jordan, J.; Decker, M.

    1990-11-01

    The Wave Propagation Laboratory has been operating a six-channel radiometer profiler since 1981 at Stapleton International Airport in Denver, Colorado, to retrieve temperature profiles. The atmospheric absorption at these frequencies is too large for tipping calibrations to be used. Therefore, data from collocated National Weather Service radiosondes were used to calibrate the radiometric profiles. The technique provides the necessary profiler calibration but limits its use to locations with regular radiosonde launches. Therefore, a prototype calibration transfer target was constructed at Stapleton Airport to demonstrate the feasibility of using the target to help maintain a network of radiometric profilers not located at radiosonde sites. The calibration target is described, along with potential error sources.

  13. Survey of emissivity measurement by radiometric methods.

    PubMed

    Honner, M; Honnerová, P

    2015-02-01

    A survey of the state of the art in the field of spectral directional emissivity measurements by using radiometric methods is presented. Individual quantity types such as spectral, band, or total emissivity are defined. Principles of emissivity measurement by various methods (direct and indirect, and calorimetric and radiometric) are discussed. The paper is focused on direct radiometric methods. An overview of experimental setups is provided, including the design of individual parts such as the applied reference sources of radiation, systems of sample clamping and heating, detection systems, methods for the determination of surface temperature, and procedures for emissivity evaluation. PMID:25967774

  14. Radiometric rectification - Toward a common radiometric response among multidate, multisensor images

    NASA Technical Reports Server (NTRS)

    Hall, F. G.; Strebel, D. E.; Nickeson, J. E.; Goetz, S. J.

    1991-01-01

    A method is developed for relating scene digital counts among several images of the same scene by identifying radiometric control sets with mean reflectances that are basically constant. The average digital-count values of the control sets are utilized to compute linear transforms that relate digital count values between images. Two Landsat TM images are studied by means of the technique using simulations of a wide range of atmospheric conditions. In the visible and near-IR bands the algorithm effectively adjusts the surface reflectance for the effects of relative atmospheric differences to within 1 percent. The proposed method is found to be an effective relative correction procedure that can be used when atmospheric optical-depth data and calibration coefficients are not available.

  15. Structural and radiometric asymmetry in brain images.

    PubMed

    Joshi, Sarang; Lorenzen, Peter; Gerig, Guido; Bullitt, Elizabeth

    2003-06-01

    This paper presents a general framework for analyzing structural and radiometric asymmetry in brain images. In a healthy brain, the left and right hemispheres are largely symmetric across the mid-sagittal plane. Brain tumors may belong to one or both of the following categories: mass-effect, in which the diseased tissue displaces healthy tissue; and infiltrating, in which healthy tissue has become diseased. Mass-effect brain tumors cause structural asymmetry by displacing healthy tissue, and may cause radiometric asymmetry in adjacent normal structures due to edema. Infiltrating tumors have a different radiometric response from healthy tissue. Thus, structural and radiometric asymmetries across the mid-sagittal plane in brain images provide important cues that tumors may be present. We have developed a framework that registers images with their reflections across the mid-sagittal plane. The registration process accounts for tissue displacement through large deformation image warping. Radiometric differences are taken into account through an additive intensity field. We present an efficient multi-scale algorithm for the joint estimation of structural and radiometric asymmetry. Results for nine MR images of patients with tumors and four normal control subjects are presented. PMID:12868619

  16. Results of magnetic HGI and radiometric surveys in W. Canada

    SciTech Connect

    LeSchack, L.A.

    1997-05-19

    This article presents four case histories in which ground-based magnetic horizontal gradient intensity (HGI) and radiometric surveys were used in Western Canada for cost-effective geochemical exploration for hydrocarbons. The authors has developed these two surface exploration techniques from published studies and adapted them for use on the prairies the past 7 years. These surveys are used in conjunction with the usual geologic and seismic studies for: (1) evaluating prospects and land; (2) verifying seismic anomalies and inexpensively locating areas for conducting expensive 3D seismic surveys. Occasionally, as in two of the case histories discussed, these surveys were used successfully as stand-alone exploration methods where seismic exploration is not effective. The HGI and radiometric surveys measure, by geophysical methods, those effects associated with geochemical alterations due to vertical microseepage of hydrocarbons. The total cost, including permitting, data acquisition, data processing, and interpretation of the combination HGI and radiometric surveys is about 15% the total cost of a 3D seismic survey. Because of this, the author finds them an attractive and rapid survey adjunct to traditional exploration. They substantially reduce finding costs and significantly raise the probability of financial success.

  17. Selection of chemotherapy for patient treatment utilizing a radiometric versus a cloning system

    SciTech Connect

    Von Hoff, D.D.; Forseth, B.J.; Turner, J.N.; Clark, G.M.; Warfel, L.E.

    1986-01-01

    From the 1950s to the 1970s, a number of in vitro systems that measured inhibition of glucose metabolism were used to predict the responsiveness of patients' tumors to chemotherapy. In vitro-in vivo correlations were excellent, with true positive predictions ranging from 68% to 96% and true negative predictions of 95% to 100%. The radiometric system is a new in vitro technique that measures the conversion of 14C-glucose to 14CO2. The system already has been utilized to screen prospective new antineoplastic agents for cytotoxicity. The present study was undertaken to determine if the radiometric system might be used to predict correctly the responsiveness of an individual patient's tumor to single-agent or combination-agent chemotherapy. Fifty-six tumor specimens were divided and tested for drug sensitivity in the radiometric system and a conventional human tumor clonning system. Overall, there was a significant correlation between in vitro and in vivo results for the conventional cloning system (P = 0.03). However, there was no significant relationship between in vitro and in vivo results for the radiometric system. The radiometric system consistently failed to predict the tumor's clinical sensitivity to single agents. A radiometric system is not useful in predicting the responsiveness of a patient's tumor to single agent chemotherapy and is not a replacement for the more biologically attractive human tumor cloning system.

  18. Helium-4 characteristics of groundwaters from Central Australia: Comparative chronology with chlorine-36 and carbon-14 dating techniques

    NASA Astrophysics Data System (ADS)

    Kulongoski, Justin T.; Hilton, David R.; Cresswell, Richard G.; Hostetler, Stephen; Jacobson, Gerry

    2008-01-01

    SummaryHelium isotope and concentration characteristics were determined for a suite of groundwater samples from the Amadeus Basin in Central Australia. Two study areas include a wellfield south of Alice Springs, and the Dune Plains and Mututjulu aquifers near Uluru. Measurements of 36Cl/Cl and 14C on the same sample suite enable us to assess the relative applicability of the three groundwater chronometers over a range of anticipated groundwater residence times (ages), and to investigate possible causes of discordant 'ages' derived from the different groundwater dating techniques. Results from the analyses of 39 groundwater samples reveal helium-4 ( 4He) concentrations that range from 0.80 to 98.8 (10 -7 cm 3 STP g -1 H 2O) in the Alice Springs samples, and from 0.47 to 65.6 (10 -7 cm 3 STP g -1 H 2O) in the Uluru samples. 4He concentrations yield uncorrected groundwater residence times (i.e. time since recharge) of between modern to >2500 ka (near Alice Springs) and modern to 1600 ka (near Uluru) assuming an effective porosity of 20%, and uranium and thorium contents of 1.7 and 6.1 ppm, respectively. 36Cl/Cl ratios on the same samples range from 93 to 158 (10 -15) (near Alice Springs) and from 80 to 335 (10 -15) (near Uluru) representing groundwater residence times near Alice Springs from modern to >200 ka, and from modern to >300 ka near Uluru. Percent modern carbon (pmc) on the same samples ranged from 64.9 to 12.5 pmc near Alice Springs, and from 93.5 to <2 pmc near Uluru. Corresponding 14C residence times for the Alice Springs samples range from modern to 13.0 ka, and near Uluru from modern to >30 ka. For the Amadeus Basin groundwater samples, the 4He method (uncorrected) over-estimates groundwater residence time compared to 36Cl and 14C techniques. This implies the presence of an extraneous He component or basal flux of He ( J0). To reconcile groundwater 4He and 14C residence times, it is necessary to adopt J0 values between 0 and 30 (10 -8) cm 3 STP He cm -2 a -1 which supplements in situ produced He within the aquifer. Adoption of J0 values over this range lowers 4He residence times relative to 36Cl and produces closer agreement between the 4He and 14C chronometers. The extraneous He component (basal flux) in Amadeus Basin samples is dominated by radiogenic crustal 4He without a detectable amount of mantle-derived 3He. We conclude that the stable tectonic regime, albeit with the presence of major faults within the basin, inhibits the input of mantle volatiles to the groundwater system so that in this region, diffusion is the dominant transport mechanism for He in the crust.

  19. Radiometric surveys in underground environment

    NASA Astrophysics Data System (ADS)

    Bochiolo, Massimo; Chiozzi, Paolo; Verdoya, Massimo; Pasquale, Vincenzo

    2010-05-01

    Due to their ability to travel through the air for several metres, gamma-rays emitted from natural radioactive elements can be successfully used in surveys carried out both with airborne and ground equipments. Besides the concentration of the radio-elements contained in rocks and soils and the intrinsic characteristics of the gamma-ray detector, the detected count rate depends on the solid angle around the spectrometer. On a flat outcrop, ground spectrometry detects the radiation ideally produced by a cylindrical mass of rock of about two metres in diameter and thickness of about half a meter. Under these geometrical conditions, the natural radioactivity can be easily evaluated. With operating conditions different from the standard ones, such as at the edge of an escarpment, the count rate halves because of the missing material, whereas in the vicinity of a rock wall the count rate will increase. In underground environment, the recorded count rate may even double and the in situ assessment of the concentration of radio-elements may be rather difficult, even if the ratios between the different radio-elements may not be affected. We tested the applicability of gamma-ray spectrometry for rapid assessment of the potential hazard levels related to radon and radiation dose rate in underground environment. A mine shaft, located in a zone of uranium enrichment in Liguria (Italy), has been investigated. A preliminary ground radiometric survey was carried out to define the extent of the ore deposit. Then, the radiometric investigation was focussed on the mine shaft. Due to rock mass above the shaft vault, the background gamma radiation can be considered of negligible influence on measurements. In underground surveys, besides deviations from a flat geometry, factors controlling radon exhalation, emanation and stagnation, such as fractures, water leakage and the presence of ventilation, should be carefully examined. We attempted to evaluate these control factors and collected a set of rock samples along the mine shaft to compare in situ results with high resolution gamma-ray analysis in the laboratory. The comparison points to a systematic overestimation (on the average, by a factor of two) of the uranium, thorium and potassium concentrations obtained with the portable apparatus. The bias between laboratory and field is slightly smaller for potassium and could be due only to deviation from standard geometric conditions. The largest differences occur in uranium concentrations, probably due also to the influence of the activity deriving from radon stagnation. The calculated radon flux depends on the radium specific activity, which, under the assumption of secular radioactive equilibrium, can be easily inferred from the uranium concentration, and the specific exhalation coefficient. Measurements of specific exhalation coefficient are difficult and only few studies have examined unaltered rocks in details. We estimated the values of this parameter by considering the degree of fracturing, width of fissures and evidence of percolating groundwater. In general, the coefficient increases from the entrance, where rocks are more massive, towards the shaft bottom, where closely spaced open fissures, often filled with percolating groundwater, might boost exhalation. As a whole, both potential radon flux and radiation dose values are relevant to radio protection rules.

  20. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band

    SciTech Connect

    Flittner, D.E.; Herman, B.M.; Thome, K.J.; Simpson, J.M.; Reagan, J.A. )

    1993-04-15

    A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.

  1. Investigation of Pre- and Post-Flight Radiometric Calibration Uncertainties from Surface Based Measurements

    SciTech Connect

    Heath, D.F.; Wei, Z.Y.; Ahman, Z.

    1997-06-01

    A new technique has been developed for inferring column ozone amounts and aerosol optical depths from zenith sky observations. A new radiometric calibration technique for large aperture remote sensing instruments observing the earth through space has been validated which subsequently increased the accuracy of remote sensing measurements of ozone and vertical profiles using measurements of back-scattered ultraviolet solar radiation.

  2. Age of Barrier Canyon-style rock art constrained by cross-cutting relations and luminescence dating techniques.

    PubMed

    Pederson, Joel L; Chapot, Melissa S; Simms, Steven R; Sohbati, Reza; Rittenour, Tammy M; Murray, Andrew S; Cox, Gary

    2014-09-01

    Rock art compels interest from both researchers and a broader public, inspiring many hypotheses about its cultural origin and meaning, but it is notoriously difficult to date numerically. Barrier Canyon-style (BCS) pictographs of the Colorado Plateau are among the most debated examples; hypotheses about its age span the entire Holocene epoch and previous attempts at direct radiocarbon dating have failed. We provide multiple age constraints through the use of cross-cutting relations and new and broadly applicable approaches in optically stimulated luminescence dating at the Great Gallery panel, the type section of BCS art in Canyonlands National Park, southeastern Utah. Alluvial chronostratigraphy constrains the burial and exhumation of the alcove containing the panel, and limits are also set by our related research dating both a rockfall that removed some figures and the rock's exposure duration before that time. Results provide a maximum possible age, a minimum age, and an exposure time window for the creation of the Great Gallery panel, respectively. The only prior hypothesis not disproven is a late Archaic origin for BCS rock art, although our age result of A.D. ? 1-1100 coincides better with the transition to and rise of the subsequent Fremont culture. This chronology is for the type locality only, and variability in the age of other sites is likely. Nevertheless, results suggest that BCS rock art represents an artistic tradition that spanned cultures and the transition from foraging to farming in the region. PMID:25157162

  3. Age of Barrier Canyon-style rock art constrained by cross-cutting relations and luminescence dating techniques

    PubMed Central

    Pederson, Joel L.; Chapot, Melissa S.; Simms, Steven R.; Sohbati, Reza; Rittenour, Tammy M.; Murray, Andrew S.; Cox, Gary

    2014-01-01

    Rock art compels interest from both researchers and a broader public, inspiring many hypotheses about its cultural origin and meaning, but it is notoriously difficult to date numerically. Barrier Canyon-style (BCS) pictographs of the Colorado Plateau are among the most debated examples; hypotheses about its age span the entire Holocene epoch and previous attempts at direct radiocarbon dating have failed. We provide multiple age constraints through the use of cross-cutting relations and new and broadly applicable approaches in optically stimulated luminescence dating at the Great Gallery panel, the type section of BCS art in Canyonlands National Park, southeastern Utah. Alluvial chronostratigraphy constrains the burial and exhumation of the alcove containing the panel, and limits are also set by our related research dating both a rockfall that removed some figures and the rocks exposure duration before that time. Results provide a maximum possible age, a minimum age, and an exposure time window for the creation of the Great Gallery panel, respectively. The only prior hypothesis not disproven is a late Archaic origin for BCS rock art, although our age result of A.D. ?11100 coincides better with the transition to and rise of the subsequent Fremont culture. This chronology is for the type locality only, and variability in the age of other sites is likely. Nevertheless, results suggest that BCS rock art represents an artistic tradition that spanned cultures and the transition from foraging to farming in the region. PMID:25157162

  4. Radiometric calibration of Landsat Thematic Mapper multispectral images

    USGS Publications Warehouse

    Chavez, P.S., Jr.

    1989-01-01

    A main problem encountered in radiometric calibration of satellite image data is correcting for atmospheric effects. Without this correction, an image digital number (DN) cannot be converted to a surface reflectance value. In this paper the accuracy of a calibration procedure, which includes a correction for atmospheric scattering, is tested. Two simple methods, a stand-alone and an in situ sky radiance measurement technique, were used to derive the HAZE DN values for each of the six reflectance Thematic Mapper (TM) bands. The DNs of two Landsat TM images of Phoenix, Arizona were converted to surface reflectances. -from Author

  5. Cropland measurement using Thematic Mapper data and radiometric model

    NASA Technical Reports Server (NTRS)

    Lyon, John G.; Khuwaiter, I. H. S.

    1989-01-01

    To halt erosion and desertification, it is necessary to quantify resources that are affected. Necessary information includes inventory of croplands and desert areas as they change over time. Several studies indicate the value of remote sensor data as input to inventories. In this study, the radiometric modeling of spectral characteristics of soil and vegetation provides the theoretical basis for the remote sensing approach. Use of Landsat Thematic Mapper images allows measurement of croplands in Saudi Arabia, demonstrating the capability of the approach. The inventory techniques and remote sensing approach presented are potentially useful in developing countries.

  6. Earth Observing-1 Advanced Land Imager: Radiometric Response Calibration

    NASA Technical Reports Server (NTRS)

    Mendenhall, J. A.; Lencioni, D. E.; Evans, J. B.

    2000-01-01

    The Advanced Land Imager (ALI) is one of three instruments to be flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). ALI contains a number of innovative features, including a wide field of view optical design, compact multispectral focal plane arrays, non-cryogenic HgCdTe detectors for the short wave infrared bands, and silicon carbide optics. This document outlines the techniques adopted during ground calibration of the radiometric response of the Advanced Land Imager. Results from system level measurements of the instrument response, signal-to-noise ratio, saturation radiance, and dynamic range for all detectors of every spectral band are also presented.

  7. Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas

    USGS Publications Warehouse

    Mahan, Shannon; Kay, John

    2012-01-01

    The long term stability and reliability of the luminescence signal for gypsum has not been well documented or systematically measured until just recently. A review of the current literature for luminescence dating of gypsum is compiled here along with original efforts at dating an intact and in-situ bed of selenite gypsum at Salt Basin Playa, New Mexico and Texas. This effort differs from other documented luminescence dating efforts because the gypsum is not powdery or redistributed from its original growth patterns within the playa basin but is instead of a crystalline form. Sixteen ages from eight cores were ultimately produced with seven of the ages coming from rare detrital quartz encased in or with the gypsum crystals while the remaining ages are from the crystalline gypsum. As far as can be ascertained, the quartz was measured separately from the gypsum and no contaminants were noted in any of the aliquots. Some basic and preliminary tests of signal stability were measured and found to be mitigated by lessening of pre-heat protocols. Ages ranged from 8 ka to 10 ka in the shallow cores and 16 ka to 22 ka in the deeper cores. These ages will be useful in determining rates of gypsum growth within a sequence of evaporates which, in turn, will help to better document historic rates of evaporation and thus estimate, with more precision, the corresponding annual evaporation rates.

  8. Azimuthal radiometric temperature measurements of wheat canopies

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.

    1981-01-01

    The effects of azimuthal view angle on the radiometric temperature of wheat canopies at various stages of development are investigated. Measurements of plant height, total leaf area index, green leaf area index and Feeks growth stage together with infrared radiometric temperature measurements at 12 azimuth intervals with respect to solar azimuth and at different solar zenith angles were obtained for four wheat canopies at various heights. Results reveal a difference on the order of 2 C between the temperatures measured at azimuths of 0 and 180 deg under calm wind conditions, which is attributed to the time-dependent transfer of heat between canopy component surfaces. The azimuthal dependence must thus be taken into account in the determination of radiometric temperatures.

  9. AIRS radiometric calibration validation for climate research

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Pagano, Thomas S.; Elliott, Denis; Gaiser, Steve; Gregorich, Dave; Broberg, Steve

    2005-01-01

    Climate research using data from satellite based radiometers makes extreme demands on the traceability and stability of the radiometric calibration. The selection of a cooled grating array spectrometer for the Atmospheric Infrared Sounder, AIRS, is key, but does not ensured that AIRS data will be of climate quality. Additional design features, plus additional pre-launch testing, and extensive on-orbit calibration subsystem monitoring beyond what would suffice for application of the data to weather forecasting were required to ensure the radiometric data quality required for climate research. Validation that climate data quality are being generated makes use of the sea surface skin temperatures (SST and (obs-calc).

  10. Experimental methods of indoor millimeter-wave radiometric imaging for personnel concealed contraband detection

    NASA Astrophysics Data System (ADS)

    Hu, Taiyang; Xiao, Zelong; Li, Hao; Lv, Rongchuan; Lu, Xuan

    2014-11-01

    The increasingly emerging terrorism attacks and violence crimes around the world have posed severe threats to public security, so carrying out relevant research on advanced experimental methods of personnel concealed contraband detection is crucial and meaningful. All of the advantages of imaging covertly, avoidance of interference with other systems, intrinsic property of being safe to persons under screening , and the superior ability of imaging through natural or manmade obscurants, have significantly combined to enable millimeter-wave (MMW) radiometric imaging to offer great potential in personnel concealed contraband detection. Based upon the current research status of MMW radiometric imaging and urgent demands of personnel security screening, this paper mainly focuses on the experimental methods of indoor MMW radiometric imaging. The reverse radiation noise resulting from super-heterodyne receivers seriously affects the image experiments carried out at short range, so both the generation mechanism and reducing methods of this noise are investigated. Then, the benefit of sky illumination no longer exists for the indoor radiometric imaging, and this leads to the decrease in radiometric temperature contrast between target and background. In order to enhance the radiometric temperature contrast for improving indoor imaging performance, the noise illumination technique is adopted in the indoor imaging scenario. In addition, the speed and accuracy of concealed contraband detection from acquired MMW radiometric images are usually restricted to the deficiencies in traditional artificial interpretation by security inspectors, thus an automatic recognition and location algorithm by integrating improved Fuzzy C-means clustering with moment invariants is put forward. A series of original results are also presented to demonstrate the significance and validity of these methods.

  11. Shaft speleogenesis in Picos de Europa (North Spain): contribution of cave geomorphological mapping and U-Th dating techniques

    NASA Astrophysics Data System (ADS)

    Ballesteros, D.; Jimnez-Snchez, M.; Giralt, S.; Garca-Sansegundo, J.; Sendra, G.

    2012-04-01

    Picos de Europa Mountains are located in the North of Spain, showing more than 2,000 m thickness of Carboniferous limestone, in which the 14 % of the deepest shafts of the world are developed. This work concerns with a speleogenetical research carried out in two shafts (Torca Teyera and La Texa), using geomorphological maps and U-Th dating. The spatial distribution of cave geomorphological processes is established by the elaboration of geomorphological maps at a 1:500 scale, using genetical criteria for the classification of cave features. Cave temporal evolution is established from relative chronology between cave features and deposits and absolute dating of eight selected samples with U-series disintegration (234U/230Th). Torca Teyera Shaft (4 52' 56.9'' W 43 16' 33.1'' N) is a multilevel cave 4,438 m long and 738 m deep with three cave levels located at 1,300, 800-900 and 615 m.a.s.l. Cave levels are formed by phreatic and epiphreatic tubes strongly modified by vadose stream incision and breakdown processes. Fluvial and slackwater deposits, frequently covering breakdown deposits, are preserved up to 70 m over the active level and reach thickness of 3 m, appearing sometimes interbedded with flowstone. Flowstone levels usually fossilize fluvial deposits, being covered by other speleothems, as stalagmites and pool deposits. La Texa shaft (4 58'1.3'' W 43 15'45.2'' N), 2,231 m long and 215 m deep, presents only one cave level at 1,300 m a.s.l. formed by phreatic and epiphreatic tubes modified by vadose incision. Flowstones and dripstones are often covering fluvial (slackwater deposits) and gravity deposits, being the last the most frequently feature in shaft bottom. Eight speleothem samples from the two shafts were dated using the U-series disintegration method. Two flowstones from the middle cave level of Torca Teyera yielded ages of 185 and 238 ka, respectively. The age of a pool deposit sample and of a flowstone from the upper level exceeded 300 ka. On the other hand, three flowstone samples from Torca La Texa were dated between 156 and 181 ka, whereas the third sample is out of range of the U-Th method. Finally, one sample of a pool deposit found over flowstones is dated at 65 ka. These ages allowed us to establish a preliminary chronology of the speleogenetic events. The development of Torca Teyera and La Texa began at least during the Mid Pleistocene and in both cases it was controlled by the dropping of the base level. Fluvial activity and the grow of speleothems started prior 300 ka and both processes have been continuous up to at least 185 ka, at the middle level of Torca Teyera, and up to 156 ka at Torca La Texa. The most important flowstone of Torca La Texa precipitated at about 65 ka ago. These results are consistent to validate the previous speleogenetical models in the area, in which new shafts and canyons began to develop downwards cutting the old cave levels that remained perched during Alpine uplift.

  12. The absolute radiometric calibration of the Landsat 8 Operational Land Imager using the reflectance-based approach and the Radiometric Calibration Test Site (RadCaTS)

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey; Anderson, Nikolaus; Thome, Kurtis; Biggar, Stuart

    2014-10-01

    Landsat 8 was launched on 11 February 2013 as the newest platform in the Landsat program. It contains two Earthobserving instruments, one of which is the Operational Land Imager (OLI). OLI includes an onboard radiometric calibration system that is used to monitor changes in its responsivity throughout the mission lifetime, and it consists of Spectralon solar diffuser panels as well as tungsten lamp assemblies. External techniques are used to monitor both OLI and its calibration system, and they include lunar views, side slither maneuvers of the satellite, and ground-based vicarious calibration. This work presents the absolute radiometric calibration results for Landsat 8 OLI that were obtained using two ground-based measurement techniques. The first is the reflectance-based approach, where measurements of atmospheric and surface properties are made during a Landsat 8 overpass, and it requires personnel to be on site during the time of measurement. The second uses the Radiometric Calibration Test Site (RadCaTS), which was developed by the Remote Sensing Group in the College of Optical Sciences at the University of Arizona so that radiometric calibration data can be collected without the requirement of on-site personnel. It allows more data to be collected annually, which increases the temporal sampling of trending results.

  13. Radiometric Characterization of IKONOS Multispectral Imagery

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Ryan, Robert E.; Kelly, Michelle; Holekamp, Kara; Zanoni, Vicki; Thome, Kurtis; Schiller, Stephen

    2002-01-01

    A radiometric characterization of Space Imaging's IKONOS 4-m multispectral imagery has been performed by a NASA funded team from the John C. Stennis Space Center (SSC), the University of Arizona Remote Sensing Group (UARSG), and South Dakota State University (SDSU). Both intrinsic radiometry and the effects of Space Imaging processing on radiometry were investigated. Relative radiometry was examined with uniform Antarctic and Saharan sites. Absolute radiometric calibration was performed using reflectance-based vicarious calibration methods on several uniform sites imaged by IKONOS, coincident with ground-based surface and atmospheric measurements. Ground-based data and the IKONOS spectral response function served as input to radiative transfer codes to generate a Top-of-Atmosphere radiance estimate. Calibration coefficients derived from each vicarious calibration were combined to generate an IKONOS radiometric gain coefficient for each multispectral band assuming a linear response over the full dynamic range of the instrument. These calibration coefficients were made available to Space Imaging, which subsequently adopted them by updating its initial set of calibration coefficients. IKONOS imagery procured through the NASA Scientific Data Purchase program is processed with or without a Modulation Transfer Function Compensation kernel. The radiometric effects of this kernel on various scene types was also investigated. All imagery characterized was procured through the NASA Scientific Data Purchase program.

  14. Based on Narcissus of radiometric calibration technology

    NASA Astrophysics Data System (ADS)

    Jin, Libing; Tang, Shaofan; Liu, Jianfeng; Peng, Honggang

    2015-08-01

    Thermal radiation is an inherent property of all objects. Generally, it is believed that the body, which temperature is above absolute zero, can keep generating infrared radiation. Infrared remote sensing, using of satellite-borne or airborne sensors, collects infrared information to identify the surface feature and inversion of surface parameters, temperature, etc. In order to get more accurately feature information, quantitative measurement is required. Infrared radiometric calibration is one of the key technologies of quantitative infrared remote sensing. Most high-resolution thermal imaging systems are cooling. For the infrared optical system which is having a cooled detector, there are some special phenomenons. Since the temperature of the detector's photosensitive surface is generally low, which is very different from system temperature, it is a very strong cold radiation source. Narcissus refers to the case that the cooled detector can "see" its own reflecting image, which may affect the image quality of infrared system seriously. But for radiometric calibration of satellite-borne infrared camera, it can sometimes take advantage of the narcissus instead of cold cryogenic radiometric calibration. In this paper, the use of narcissus to carry out radiometric calibration is summarized, and simulation results show the feasibility.

  15. Radiometric surface temperature components for row crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature is a boundary condition often used in assessing soil moisture status and energy exchange from the soil-vegetation-atmosphere interface. For row crops having incomplete canopy cover, the radiometric surface temperature is a composite of sunlit and shaded vegetation and substr...

  16. Radiometric-microbiologic assay of niacin using Kloeckera brevis: analysis of human blood and food

    SciTech Connect

    Guilarte, T.R.; Pravlik, K.

    1983-12-01

    Kloeckera brevis, a yeast, was used as the test organism for the development of a radiometric-microbiologic (RMA) assay for niacin. The assay was determined to be sensitive to the 2 ng niacin per vial level and specific for the biologically active forms of this vitamin. The method was shown to be simple, accurate, and precise in the analysis of niacin in human blood and food. The application of the radiometric technique eliminates some of the problems encountered with conventional turbidimetric-microbiologic assay.

  17. MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level VNIR/SWIR Radiometric Uncertainties

    NASA Technical Reports Server (NTRS)

    Platnick, S.; Wind, G.; Xiong, X.

    2011-01-01

    Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of optical thickness and effective particle radius for liquid water and ice phase clouds employ a well-known VNIR/ SWIR solar reflectance technique. For this type of algorithm, we evaluate the quantitative uncertainty in simultaneous retrievals of these two cloud parameters to pixel-level radiometric calibration estimates and other fundamental (and tractable) error sources.

  18. MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level Radiometric Error Estimates

    NASA Technical Reports Server (NTRS)

    Platnick, Steven; Wind, Galina; Xiong, Xiaoxiong

    2011-01-01

    MODIS retrievals of cloud optical thickness and effective particle radius employ a well-known VNIR/SWIR solar reflectance technique. For this type of algorithm, we evaluate the uncertainty in simultaneous retrievals of these two parameters to pixel-level (scene-dependent) radiometric error estimates as well as other tractable error sources.

  19. Date Rape

    MedlinePLUS

    ... Best Self Smart Snacking Losing Weight Safely Date Rape KidsHealth > Teens > Mind > Relationships > Date Rape Print A ... Getting Help Reporting a Rape What Is Date Rape? When people think of rape , they might picture ...

  20. Date Rape

    MedlinePLUS

    ... Can I Help a Friend Who Cuts? Date Rape KidsHealth > For Teens > Date Rape Print A A ... en español Violaciones durante citas What Is Date Rape? When people think of rape , they might picture ...

  1. Radiometric calibration and stability of the Landsat-8 Operational Land Imager (OLI)

    NASA Astrophysics Data System (ADS)

    Markham, Brian L.; Barsi, Julia A.; Kaita, Edward; Ong, Lawrence; Morfitt, Ron A.; Haque, Md. O.

    2015-09-01

    Landsat-8 and its two Earth imaging sensors, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) have been operating on-orbit for 2 1/2 years. The OLI radiometric calibration, which is monitored using on-board lamps, on-board solar diffusers, the moon and vicarious calibration techniques has been stable to within 1% over this period of time. The Coastal Aerosol band, band 1, shows the largest change at about 1% over the period; all other bands have shown no significant trend. OLI bands 1- 4 show small discontinuities in response (+0.1% to 0.2%) beginning about 7 months after launch and continuing for about 1 month associated with a power cycling of the instrument, though the origin of the recovery is unclear. To date these small changes have not been compensated for, but this will change with a reprocessing campaign that is currently scheduled for Fall 2015. The calibration parameter files (each typically covering a 3 month period) will be updated for these observed gain changes. A fitted response to an adjusted average of the lamps, solar and lunar results will represent the trend, sampled at the rate of one value per CPF.

  2. Dating Violence

    ERIC Educational Resources Information Center

    Stader, David L.

    2011-01-01

    Dating violence is a form of student-on-student victimization and is a serious school safety issue. Research indicates that at a minimum, 10 percent of high school students are victims of dating violence in one form or another. Among female high school students that date, some data indicate that as many as 30 percent may be victims of dating

  3. Radiometric tests on wet and dry antenna reflector surface panels

    NASA Technical Reports Server (NTRS)

    Otoshi, T. Y.; Franco, M. M.

    1990-01-01

    The results of X-band noise temperature tests on two types of antenna surface panels are presented. The first type tested was a solid antenna panel, while the second type was a perforated panel with 3/16-in.-diameter holes. Measurements were made at 8.45 GHz using an X-band radiometric system. Included in this article are measured noise temperature contributions from: (1) thermal diffusive white paint on solid and perforated panels, and (2) water sprayed on both painted and unpainted perforated panels. Experiments on perforated panels were restricted to the 3/16-in.-diameter hole panels formerly used on Deep Space Network 64-m antennas. Rigorous calibration equations, applicable to a variety of antenna panel and dichroic plate test configurations, are presented. It was demonstrated that an accurate, stable radiometric measurement system of the type used for the results of this research makes it possible to obtain information that would be much more difficult to obtain using other techniques.

  4. Principal Component Noise Filtering for NAST-I Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Tian, Jialin; Smith, William L., Sr.

    2011-01-01

    The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed- Interferometer (NAST-I) instrument is a high-resolution scanning interferometer that measures emitted thermal radiation between 3.3 and 18 microns. The NAST-I radiometric calibration is achieved using internal blackbody calibration references at ambient and hot temperatures. In this paper, we introduce a refined calibration technique that utilizes a principal component (PC) noise filter to compensate for instrument distortions and artifacts, therefore, further improve the absolute radiometric calibration accuracy. To test the procedure and estimate the PC filter noise performance, we form dependent and independent test samples using odd and even sets of blackbody spectra. To determine the optimal number of eigenvectors, the PC filter algorithm is applied to both dependent and independent blackbody spectra with a varying number of eigenvectors. The optimal number of PCs is selected so that the total root-mean-square (RMS) error is minimized. To estimate the filter noise performance, we examine four different scenarios: apply PC filtering to both dependent and independent datasets, apply PC filtering to dependent calibration data only, apply PC filtering to independent data only, and no PC filters. The independent blackbody radiances are predicted for each case and comparisons are made. The results show significant reduction in noise in the final calibrated radiances with the implementation of the PC filtering algorithm.

  5. Microwave radiometric signatures of temperature anomalies in tissue

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick; Sobers, Tamara; St. Peter, Benjamin; Siqueira, Paul; Capraro, Geoffrey

    2012-03-01

    Because of its ability to measure the temperature-dependent power of electromagnetic radiation emitted from tissue down to several centimeters beneath the skin, microwave radiometry has long been of interest as a means for identifying the internal tissue temperature anomalies that arise from abnormalities in physiological parameters such as metabolic and blood perfusion rates. However, the inherent lack of specificity and resolution in microwave radiometer measurements has limited the clinical usefulness of the technique. The idea underlying this work is to make use of information (assumed to be available from some other modality) about the tissue configuration in the volume of interest to study and improve the accuracy of anomaly detection and estimation from radiometric data. In particular, knowledge of the specific anatomy and the properties of the overall measurement system enable determination of the signatures of localized physiological abnormalities in the radiometry data. These signatures are used to investigate the accuracy with which the location of an anomaly can be determined from radiometric measurements. Algorithms based on matches to entries in a signature dictionary are developed for anomaly detection and estimation. The accuracy of anomaly identification is improved when the coupling of power from the body to the sensor is optimized. We describe the design of a radiometer waveguide having dielectric properties appropriate for biomedical applications.

  6. Climate Change and Sounder Radiometric Stability

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Manning, Evan

    2009-01-01

    Satellite instrument radiometric stability is critical for climate studies. The Atmospheric Infrared Sounder (AIRS) radiances are of sufficient stability and accuracy to serve as a climate data record as evidenced by comparisons with the global network of buoys. In this paper we examine the sensitivity of derived geophysical products to potential instrument radiometric stability issues due to diurnal, orbital and seasonal variations. Our method is to perturb the AIRS radiances and examine the impact to retrieved parameters. Results show that instability in retrieved temperature products will be on the same order of the brightness temperature error in the radiances and follow the same time dependences. AIRS excellent stability makes it ideal for examining impacts of instabilities of future systems on geophysical parameter performance.

  7. A radiometric Bode's Law: Predictions for Uranus

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Kaiser, M. L.

    1984-01-01

    The magnetospheres of three planets, Earth, Jupiter, and Saturn, are known to be sources of intense, nonthermal radio bursts. The emissions from these sources undergo pronounced long term intensity fluctuations that are caused by the solar wind interaction with the magnetosphere of each planet. Determinations by spacecraft of the low frequency radio spectra and radiation beam geometry now permit a reliable assessment of the overall efficiency of the solar wind in stimulating these emissions. Earlier estimates of how magnetospheric radio output scales with the solar wind energy input must be revised greatly, with the result that, while the efficiency is much lower than previously thought, it is remarkably uniform from planet to planet. The formulation of a radiometric Bode's Law from which a planet's magnetic moment is estimated from its radio emission output is presented. Applying the radiometric scaling law to Uranus, the low-frequency radio power is likely to be measured by the Voyager 2 spacecraft as it approaches this planet.

  8. A LASER RIMS Instrument to Date Igneous Rocks using Rb-Sr and Measure Elemental Chemistry

    NASA Astrophysics Data System (ADS)

    Osterloo, M. M.; Anderson, F. S.; Whitaker, T.; Miller, G.; Young, D.; Mahoney, J.; Norman, M.

    2005-12-01

    Deriving global estimates of planetary geochronology from cratering statistics remains difficult because estimates of the cratering rate for planets other than the Earth and the Moon are poorly constrained. Obtaining an in-situ radiometric date for the surface of a planet provides an important constraint on the rate of crater production. The result of such a measurement is twofold: first an exact date for a local region can be determined, and secondly, global geochronology from cratering statistics becomes significantly more robust. We are building an instrument to obtain a Rubidium-Strontium (Rb-Sr) date using a laser ablation (LA) resonance ionization (RI) technique. The instrument is attractive because it has virtually no moving parts, requires minimal sample preparation, and could work with existing coring and surface grinding technologies. An additional benefit of this technique is that it can obtain elemental abundances with an accuracy of 1% or better, which is sufficient for understanding normative mineralogy, weathering and exposure to water, and sample petrogenesis. Generating a Rb-Sr date using an isochron approach requires measuring 87Sr/86Sr with a precision of better than 0.1% (preferably 0.02%), and measuring 87Rb/86Sr with a precision of better than 1%. We present data that demonstrate that off-the-shelf instruments without any calibration or optimization can measure 87Sr/86Sr using RI to a precision of 0.14%, and 87Rb/86Sr using LA to 0.6%, suggesting that an optimized LA/RI technique could be used to successfully obtain an in-situ radiometric date.

  9. Methods for LWIR Radiometric Calibration and Characterization

    NASA Technical Reports Server (NTRS)

    Ryan, Robert; Harrington, Gary; Howell, Dane; Pagnutti, Mary; Zanoni, Vicki

    2002-01-01

    The utility of a remote sensing system increases with its ability to retrieve surface temperature or radiance accurately. Research applications, such as sea temperature and power plant discharge, require a 0.2 C resolution or better for absolute temperature retrievals. Other applications, including agriculture water stress detection, require at least a 1 C resolution. To achieve these levels of accuracy routinely, scientists must perform laboratory and onboard calibration, as well as in-flight vicarious radiometric characterization. A common approach used for in-flight radiometric characterization incorporates a well-calibrated infrared radiometer that is mounted on a bouy and placed on a uniform water body. The radiometer monitors radiant temperature along with pressure, humidity, and temperature measurements of an associated column of atmosphere. On very still waters, however, a buoy can significantly distrub these measurements. Researchers at NASA's Stennis Space Center (SSC) have developed a novel approach of using an uncooled infrared camera mounted on a boom to quantify buoy effects. Another critical aspect of using buoy-mounted infrared radiometers is the need for extensive laboratory characterization of the instruments' radiometric sensitivity, field of view, and spectral response. Proper surface temperature retrieval also requires detailed knowledge of both the upward emission and the reflected sky emission. Recent work at SSC has demonstrated that the use of a polarization-based radiometer operating at the Brewster angle can greatly simplify temperature retrieval as well as improve overall accuracy.

  10. Radiometric and equivalent isothermal surface temperatures

    NASA Astrophysics Data System (ADS)

    Crago, Richard D.

    1998-11-01

    The analytical solution for the heat flux from an anisothermal canopy developed from K theory by Brutsaert and Sugita [1996] (hereinafter referred to as B&S) has been extended to provide a parameterization of the difference between the radiometric and the equivalent isothermal surface temperature. The latter is the isothermal temperature at which a canopy would give the correct sensible heat flux if the sensible heat roughness length z0h was given its theoretical, isothermal value derived by B&S. A parameterization of the canopy temperature seen by a radiometer is developed which incorporates the same foliage temperature profile as that used by B&S. From this the weighting fraction (i.e., the fraction of canopy top versus canopy bottom temperature "seen" by the radiometer) can be derived, as can an equation for the view zenith angle at which the radiometric and equivalent isothermal surface temperatures are the same. Field data indicate that multiangle radiometric surface temperatures alone cannot determine the three unknowns describing the foliage temperature profile. Several strategies to overcome this problem are outlined. The parameterization may eventually help to interpret remotely sensed infrared surface temperatures and to improve estimates of sensible heat flux and evapotranspiration, but comprehensive field testing is still needed.

  11. Revised landsat-5 thematic mapper radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Markham, B.L.; Barsi, J.A.

    2007-01-01

    Effective April 2, 2007, the radiometric calibration of Landsat-5 (L5) Thematic Mapper (TM) data that are processed and distributed by the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) will be updated. The lifetime gain model that was implemented on May 5, 2003, for the reflective bands (1-5, 7) will be replaced by a new lifetime radiometric-calibration curve that is derived from the instrument's response to pseudoinvariant desert sites and from cross calibration with the Landsat-7 (L7) Enhanced TM Plus (ETM+). Although this calibration update applies to all archived and future L5 TM data, the principal improvements in the calibration are for the data acquired during the first eight years of the mission (1984-1991), where the changes in the instrument-gain values are as much as 15%. The radiometric scaling coefficients for bands 1 and 2 for approximately the first eight years of the mission have also been changed. Users will need to apply these new coefficients to convert the calibrated data product digital numbers to radiance. The scaling coefficients for the other bands have not changed. ?? 2007 IEEE.

  12. NASA IKONOS Multispectral Radiometric Calibration and 3-Year Temporal Stability Assessment

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Carver, David; Holekamp, Kara; Ryan, Robert; Zanoni, Vicki; Thome, Kurtis; Schiller, Stephen; Aaran, David

    2003-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can place confidence in the imagery they use and can fully understand its properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other system. In addition, the user community has little or no insight into the design and operation of commercial sensors or into the methods involved in generating commercial products. To address this calibration need, the NASA Stennis Space Center (SSC) Earth Science Applications (ESA) Directorate established a commercial satellite imaging radiometric calibration team consisting of three independent groups: NASA, SSC,ESA, the University of Arizona Remote Sensing Group, and South Dacota State University. Each group determined the absolute radiometric calibration coefficients of the Space Imaging IKONOS 4-band, 4 m multispectral product covering the visible through near-infrared spectral region. For a three year period beginning in 2000, each team employed some variant of a reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with IKONOS image acquisitions and radiative transfer calculations. Several study sites throughout the United States were employed that covered nearly the entire dynamic range of the IKONOS sensor. IKONOS at-sensor radiance values were compared to those estimated by each independent group to determine the IKONOS sensor's radiometric accuracy and stability. Over 10 individual vicariously determined at-sensor radiance estimates were used each year. When combined, these estimates provided a high-precision radiometric gain calibration coefficient. No significant calibration offset was observed. The results of this evaluation provide the scientific community with an independent assessment of the IKONOS sensor's absolute calibration and temporal stability over the 3-year period. While the techniques and method described in this paper reflect those developed at the NASA SSC, the results of the entire team are included.

  13. Radiocarbon dates on bones of extinct birds from Hawaii

    SciTech Connect

    James, H.F.; Stafford, T.W. Jr.; Steadman, D.W.; Olson, S.L.; Martin, P.S.; Jull, A.J.; McCoy, P.C.

    1987-04-01

    Bones from a stratified sedimentary deposit in the Puu Naio Cave site on Maui, Hawaiian Islands, reveal the late Holocene extinction of 19 species of birds. The age of the sediment and associated fauna was determined by direct radiocarbon dating (tandem particle accelerator-mass spectrometer; TAMS) of amino acids extracted from bones weighing as little as 450 mg. The /sup 14/C dates indicate that sediment has been accumulating in the lava tube for at least the last 7750 years, a suitable time frame for testing the hypothesis that Holocene extinction on islands began after human colonization. Despite growing evidence that a worldwide wave of extinctions coincided with human colonization of oceanic islands, little radiometric data have been available to date the extinction of most small fossil vertebrates on islands. The TAMS technique of dating purified collagen from the bones of small vertebrates could lead to vastly improved chronologies of extinction for oceanic islands where catastrophic mid- to late-Holocene extinction is expected or known to have occurred. Chronologies derived from nonarcheological sites that show continuous sedimentation, such as the Puu Naio Cave deposit, may also yield key evidence on the timing of earliest human settlement of Oceania.

  14. Radiocarbon dates on bones of extinct birds from Hawaii.

    PubMed Central

    James, H F; Stafford, T W; Steadman, D W; Olson, S L; Martin, P S; Jull, A J; McCoy, P C

    1987-01-01

    Bones from a stratified sedimentary deposit in the Puu Naio Cave site on Maui, Hawaiian Islands, reveal the late Holocene extinction of 19 species of birds. The age of the sediment and associated fauna was determined by direct radiocarbon dating (tandem particle accelerator-mass spectrometer; TAMS) of amino acids extracted from bones weighing as little as 450 mg. The 14C dates indicate that sediment has been accumulating in the lava tube for at least the last 7750 years, a suitable time frame for testing the hypothesis that Holocene extinction on islands began after human colonization. Despite growing evidence that a worldwide wave of extinctions coincided with human colonization of oceanic islands, little radiometric data have been available to date the extinction of most small fossil vertebrates on islands. The TAMS technique of dating purified collagen from the bones of small vertebrates could lead to vastly improved chronologies of extinction for oceanic islands where catastrophic mid- to late-Holocene extinction is expected or known to have occurred. Chronologies derived from nonarcheological sites that show continuous sedimentation, such as the Puu Naio Cave deposit, may also yield key evidence on the timing of earliest human settlement of Oceania. Images PMID:3470800

  15. 40Ar/(39)Ar dating of the Kapthurin Formation, Baringo, Kenya.

    PubMed

    Deino, Alan L; McBrearty, Sally

    2002-01-01

    The(40)Ar/(39)Ar radiometric dating technique has been applied to tuffs and lavas of the Kapthurin Formation in the Tugen Hills, Kenya Rift Valley. Two variants of the(40)Ar/(39)Ar technique, single-crystal total fusion (SCTF) and laser incremental heating (LIH) have been employed to date five marker horizons within the formation: near the base, the Kasurein Basalt at 0.61+/-0.04 Ma; the Pumice Tuff at 0.543+/-0.004 Ma; the Upper Kasurein Basalt at 0.552+/-0.015 Ma; the Grey Tuff at 0.509+/-0.009 Ma; and within the upper part of the formation, the Bedded Tuff at 0.284+/-0.012 Ma. The new, precise radiometric age determination for the Pumice Tuff also provides an age for the widespread Lake Baringo Trachyte, since the Pumice Tuff is the early pyroclastic phase of this voluminous trachyte eruption. These results establish the age of fossil hominids KNM-BK 63-67 and KNM-BK 8518 at approximately 0.510-0.512 Ma, a significant finding given that few Middle Pleistocene hominids are radiometrically dated. The Kapthurin hominids are thus the near contemporaries of those from Bodo, Ethiopia and Tanzania. A flake and core industry from lacustrine sediments in the lower part of the formation is constrained by new dates of 0.55-0.52 Ma, a period during which the Acheulian industry, characterized by handaxes, is known throughout East Africa. Points, typical of the Middle Stone Age (MSA), are found in Kapthurin Formation sediments now shown to date to between 0.509+/-0.009 Ma and 0.284+/-0.012 Ma. This date exceeds previous estimates for the age of the MSA elsewhere in East Africa by 49 ka, and establishes the age of Acheulian to MSA transition for the region. Evidence of the use of the Levallois technique for the manufacture of both small flakes and biface preforms, the systematic production of blades, and the use and processing of red ochre also occurs in this interval. The presence of blades and red ochre at this depth is important as blades signify a high degree of technical competence and red ochre suggests symbolic behavior. PMID:11795974

  16. Radiometric Observation of the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Hepplewhite, C. L.

    Available from UMI in association with The British Library. Requires signed TDF. Radiometric measurements of the ocean skin temperature together with bulk water temperatures, simultaneous radiosonde ascents and satellite infra-red radiances are used in this study to investigate the oceanic skin effect, the sea surface emissivity and the atmospheric transmission of infra-red radiation, in the window region of 8 to 12 mu m. A radiometer, designed and built at Oxford as a part of this work, sensitive to infra-red radiation in the spectral range 6.5 to 14 mum, was used to obtain sea surface skin temperatures to an accuracy of between 0.20 K and 0.25 K and with a resolution of between 0.03 K and 0.05 K. The radiometer was used aboard the RRS Bransfield, one of the vessels of the British Antarctic Survey, on its annual voyage from the U.K. to Antarctica. Satellite radiances were provided by the AVHRR/2 instrument on NOAA-9, and atmospheric temperature and humidity profiles from Vaisala radiosondes launched from the ship. Investigations of the oceanic skin effect were made by comparing the measurements of skin sea surface temperature obtained using the radiometer with bulk temperatures obtained with a conventional Meteorological Office rubber bucket. In terms of the overall average of the complete Atlantic Ocean data set the skin of the sea was found to be 0.30 K cooler than the bulk, about 10 cm below the surface. There were only a few cases when the skin was warmer than the bulk and these occurred entirely in the tropics at night time. On some occasions, at higher latitudes, the skin was over 1.0 K cooler than the bulk. The variability of the skin effect was found to be smaller in the tropics and greater at higher latitudes. The sea surface emissivity was found to vary very little with sea state at viewing angles less than about 45^circ. However, at these viewing angles and under calm, clear conditions, the surface brightness temperature was observed to fall by 0.3 K from its value when viewed at the vertical. Studies of the transmission of radiation in the atmospheric window region have shown that the effect on the atmospheric temperature deficit of different water vapour continuum models can not be distinguished from the effects of aerosols. Differences between predicted satellite channel brightness temperatures and measured ones can be mostly explained by the inability to account adequately for the presence of aerosol. When there are aerosols present, the retrieval of SST from space using the split window algorithms is subject to large errors because of the anomalous spectral characteristics of the aerosol. The dual angle technique is shown to be capable of retrieving SST to a higher degree of accuracy than the multi-channel technique, particularly in the presence of aerosol.

  17. Radiocarbon Dating

    SciTech Connect

    Buchholz, B A

    2007-12-20

    Radiocarbon dating can be used to determine the age of objects that contain components that were once alive. In the case of human remains, a radiocarbon date can distinguish between a crime scene and an archeological site. Documents, museum artifacts and art objects can be dated to determine if their age is correct for the historical context. A radiocarbon date does not confirm authenticity, but it can help identify a forgery.

  18. Dating Violence

    ERIC Educational Resources Information Center

    Stader, David L.

    2011-01-01

    Dating violence is a form of student-on-student victimization and is a serious school safety issue. Research indicates that at a minimum, 10 percent of high school students are victims of dating violence in one form or another. Among female high school students that date, some data indicate that as many as 30 percent may be victims of dating…

  19. DATE PALM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter reviews date palm biology and cultivation. Date palm (Phoenix dactylifera L.) is one of the oldest fruit crops grown in the arid regions of the Arabian Peninsula, North Africa, and the Middle East. The exact origin of the date palm is unknown but most probably the area of origin w...

  20. Fission track dating of kimberlitic zircons

    NASA Astrophysics Data System (ADS)

    Haggerty, Stephen E.; Raber, Ellen; Naeser, Charles W.

    1983-04-01

    The only reliable method for dating kimberlites at present is the lengthy and specialized hydrothermal procedure that extracts 206Pb and 238U from low-uranium zircons. This paper describes a second successful method by fission track dating of large single-crystal zircons, 1.0-1.5 cm in dimension. The use of large crystals overcomes the limitations imposed in conventional fission track analysis which utilizes crushed fragments. Low track densities, optical track dispersion, and the random orientation of polished surfaces in the etch and irradiation cycle are effectively overcome. Fission track ages of zircons from five African kimberlites are reported, from the Kimberley Pool (90.3 6.5 m.y.), Orapa (87.4 5.7 and 92.4 6.1 m.y.), Nzega (51.1 3.8 m.y.), Koffiefontein (90.0 8.2 m.y.), and Val do Queve (133.4 11.5 m.y.). In addition we report the first radiometric ages (707.9 59.6 and 705.5 61.0 m.y.) of crustal zircons from kimberlites in northwest Liberia. The fission track ages agree well with earlier age estimates. Most of the zircons examined in this study are zoned with respect to uranium but linear correlations are established (by regression analysis) between zones of variable uranium content, and within zones of constant uranium content (by analysis of variance). Concordance between the fission track method and the U/Pb technique is established and we concluded that track fading from thermal annealing has not taken place. Kimberlitic zircons dated in this study, therefore, record the time of eruption.

  1. Fission track dating of kimberlitic zircons

    USGS Publications Warehouse

    Haggerty, S.E.; Raber, E.; Naeser, C.W.

    1983-01-01

    The only reliable method for dating kimberlites at present is the lengthy and specialized hydrothermal procedure that extracts 206Pb and 238U from low-uranium zircons. This paper describes a second successful method by fission track dating of large single-crystal zircons, 1.0-1.5 cm in dimension. The use of large crystals overcomes the limitations imposed in conventional fission track analysis which utilizes crushed fragments. Low track densities, optical track dispersion, and the random orientation of polished surfaces in the etch and irradiation cycle are effectively overcome. Fission track ages of zircons from five African kimberlites are reported, from the Kimberley Pool (90.3 ?? 6.5 m.y.), Orapa (87.4 ?? 5.7 and 92.4 ?? 6.1 m.y.), Nzega (51.1 ?? 3.8 m.y.), Koffiefontein (90.0 ?? 8.2 m.y.), and Val do Queve (133.4 ?? 11.5 m.y.). In addition we report the first radiometric ages (707.9 ?? 59.6 and 705.5 ?? 61.0 m.y.) of crustal zircons from kimberlites in northwest Liberia. The fission track ages agree well with earlier age estimates. Most of the zircons examined in this study are zoned with respect to uranium but linear correlations are established (by regression analysis) between zones of variable uranium content, and within zones of constant uranium content (by analysis of variance). Concordance between the fission track method and the U/Pb technique is established and we concluded that track fading from thermal annealing has not taken place. Kimberlitic zircons dated in this study, therefore, record the time of eruption. ?? 1983.

  2. Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

    DOE PAGESBeta

    Kayzar, Theresa M.; Williams, Ross W.

    2015-09-26

    The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th-234U, 226Ra-238U, 231Pa-235U, and 227Ac-235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra-238U and 227Ac-235U chronometers and provide information about nuclide migration during uranium processing.

  3. Optical Imaging and Radiometric Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Ha, Kong Q.; Fitzmaurice, Michael W.; Moiser, Gary E.; Howard, Joseph M.; Le, Chi M.

    2010-01-01

    OPTOOL software is a general-purpose optical systems analysis tool that was developed to offer a solution to problems associated with computational programs written for the James Webb Space Telescope optical system. It integrates existing routines into coherent processes, and provides a structure with reusable capabilities that allow additional processes to be quickly developed and integrated. It has an extensive graphical user interface, which makes the tool more intuitive and friendly. OPTOOL is implemented using MATLAB with a Fourier optics-based approach for point spread function (PSF) calculations. It features parametric and Monte Carlo simulation capabilities, and uses a direct integration calculation to permit high spatial sampling of the PSF. Exit pupil optical path difference (OPD) maps can be generated using combinations of Zernike polynomials or shaped power spectral densities. The graphical user interface allows rapid creation of arbitrary pupil geometries, and entry of all other modeling parameters to support basic imaging and radiometric analyses. OPTOOL provides the capability to generate wavefront-error (WFE) maps for arbitrary grid sizes. These maps are 2D arrays containing digital sampled versions of functions ranging from Zernike polynomials to combination of sinusoidal wave functions in 2D, to functions generated from a spatial frequency power spectral distribution (PSD). It also can generate optical transfer functions (OTFs), which are incorporated into the PSF calculation. The user can specify radiometrics for the target and sky background, and key performance parameters for the instrument s focal plane array (FPA). This radiometric and detector model setup is fairly extensive, and includes parameters such as zodiacal background, thermal emission noise, read noise, and dark current. The setup also includes target spectral energy distribution as a function of wavelength for polychromatic sources, detector pixel size, and the FPA s charge diffusion modulation transfer function (MTF).

  4. Visible/infrared radiometric calibration station

    NASA Astrophysics Data System (ADS)

    Byrd, Donald A.; Maier, William B., II; Bender, Steven C.; Holland, Redus F.; Michaud, Francis D.; Luetthgen, Allen L.; Christensen, R. Wynn; O'Brian, Thomas R.

    1994-09-01

    Los Alamos National Laboratories has begun construction of a visible/infrared radiometric calibration station that will allow for absolute calibration of optical and IR remote sensing instruments with clear apertures less than 16 inches in diameter in a vacuum environment. The calibration station broadband sources will be calibrated at the National Institute of Standards and Technology (NIST) and allow for traceable absolute radiometric calibration to within +/- 3% in the visible and near IR (0.4-2.5 micrometers ), and less than +/- 1% in the infrared, up to 12 micrometers . Capabilities for placing diffraction limited images of for sensor full-field flooding will exist. The facility will also include the calibration of polarization and spectra effects, spatial resolution, field of view performance, and wavefront characterization. The configuration of the vacuum calibration station consists of an off-axis 21 inch, f/3.2, parabolic collimator with a scanning fold flat in collimated space. The sources are placed, via mechanisms to be described, at the focal plane of the off-axis parabola. Vacuum system pressure will be in the 10-6 Torr range. The broadband white-light source is a custom design by LANL with guidance from Labsphere Inc. The continuous operating radiance of the integrating sphere will be from 0.0-0.006 W/cm2/Sr/micrometers (upper level quoted for approximately 500 nm wavelength). The blackbody source is also custom designed at LANL with guidance from NIST. The blackbody temperature will be controllable between 250-350 degree(s)K. Both of the above sources have 4.1 inch apertures with estimated radiometric instability at less than 1%. The designs of each of these units will be described. The monochromator and interferometer light sources are outside the vacuum, but all optical relay and beam shaping optics are enclosed within the vacuum calibration station. These sources are to be described, as well as the methodology for alignment and characterization.

  5. Enhanced radiometric detection of Mycobacterium paratuberculosis by using filter-concentrated bovine fecal specimens

    SciTech Connect

    Collins, M.T.; Kenefick, K.B.; Sockett, D.C.; Lambrecht, R.S.; McDonald, J.; Jorgensen, J.B. )

    1990-11-01

    A commercial radiometric medium, BACTEC 12B, was modified by addition of mycobactin, egg yolk suspension, and antibiotics (vancomycin, amphotericin B, and nalidixic acid). Decontaminated bovine fecal specimens were filter concentrated by using 3-microns-pore-size, 13-mm-diameter polycarbonate filters, and the entire filter was placed into the radiometric broth. Comparison of the radiometric technique with conventional methods on 603 cattle from 9 Mycobacterium paratuberculosis-infected herds found that of 75 positive specimens, the radiometric technique detected 92% while conventional methods detected 60% (P less than 0.0005). Only 3.9% of radiometric cultures were contaminated. To measure the effect of filter concentration of specimens on the detection rate, 5 cattle with minimal and 5 with moderate ileum histopathology were sampled weekly for 3 weeks. M. paratuberculosis was detected in 33.3% of nonfiltered specimens and 76.7% of filtered specimens (P less than 0.005). Detection rates were directly correlated with the severity of disease, and the advantage of specimen concentration was greatest on fecal specimens from cattle with low-grade infections. Detection times were also correlated with infection severity: 13.4 +/- 5.9 days with smear-positive specimens, 27.9 +/- 8.7 days with feces from cows with typical subclinical infections, and 38.7 +/- 3.8 days with fecal specimens from cows with low-grade infections. Use of a cocktail of vancomycin, amphotericin B, and nalidixic acid for selective suppression of nonmycobacterial contaminants was better than the commercial product PANTA (Becton Dickinson Microbiologic Systems, Towson, Md.) only when specimens contained very low numbers of M. paratuberculosis.

  6. Radiometric levitation of micron sized spheres

    NASA Astrophysics Data System (ADS)

    Lewittes, M.; Arnold, S.; Oster, G.

    1982-03-01

    Radiometric levitation of a 20-?-diam dye-impregnated glycerol sphere has been observed at intensities as low as 1 W/cm2 in air at 30 Torr. The levitation has been effected on both strongly absorbing spheres in the direction of the light and weakly absorbing spheres in the opposite sense. Both strongly and weakly absorbing spheres are found to laterally seek an intensity minimum. Consequently particles were stably held in the focused beam of an Ar+ laser (4880 ) operating in the TEM*01 (doughnut) mode.

  7. Radiometric performance assessment of Suomi NPP VIIRS SWIR Band (2.25 ?m)

    NASA Astrophysics Data System (ADS)

    Uprety, Sirish; Cao, Changyong

    2015-09-01

    Suomi NPP VIIRS SWIR band M11 (2.25 ?m) has larger radiometric uncertainty compared to the rest of the reflective solar bands. This is due to a number of reasons including prelaunch calibration uncertainties. One of the most commonly used technique to verify the radiometric stability and accuracy of VIIRS is by intercomparing it with other well calibrated radiometers such as MODIS. However one of the limitations of using MODIS is that VIIRS band M11 RSR doesn't overlap with MODIS bands at all. Thus the accuracy of intercomparison relies completely on how well the spectral differences are analyzed over the given target. Since desert sites have higher reflectance and more flat spectra, this study uses desert sites to analyze M11 radiometric performance. In order to better match the RSR between instruments, we have chosen Landsat 8 OLI SWIR band 2 (2.20 ?m) to perform intercomparison. This is mainly because OLI SWIR band 2 fully covers the VIIRS band M11 even though OLI has much wider RSR compared to VIIRS. The study suggests that there exists large radiometric inconsistency between VIIRS M11 and OLI, on the order of 5%. The impact due to spectral differences is estimated and accounted for using EO-1 Hyperion observations and MODTRAN.

  8. Amino acid racemization dating of Upper Pleistocene - Holocene terrestrial gastropods from a Mediterranean region (Murcia, SE Spain)

    NASA Astrophysics Data System (ADS)

    Garcia-Mayordomo, Julian; Ortiz, Jose E.; Torres, Trinidad; Insua-Arevalo, Juan M.; Martinez-Diaz, Jose J.; Altolaguirre, Yul; Canales-Fernandez, Maria L.; Martin-Banda, Raquel

    2014-05-01

    The amino acid racemization method has become a widely used geochronological tool for dating Quaternary deposits. The method is based on the fact that living organisms contain only L-amino acids which gradually racemize into D-amino acids after death. Thus, the D/L ratio increases with time after death until it is equal to 1, that is, when equilibrium is reached. Gastropod shells are particularly useful for amino acid racemization dating. Because the amino acid racemization method is not a numerical dating method in isolation, it needs to be calibrated, mainly with radiometric dating methods. The racemization process is genus- and temperature-dependent. In this work we present a preliminary analysis that compares the radiometric age estimated from different dating methods of a number of gastropods recovered in localities from Murcia (Southeastern Spain), with the age obtained through the amino acid racemization method. Taking advantage of recent paleoseismological research in the Murcia region (SE Spain), 28 gastropods specimens were collected from different trenches dug in young Quaternary alluvial deposits. The specimens were subsequently classified and then analyzed according to the standards protocols of the Biomolecular Stratigraphy Laboratory (UPM, Madrid School of Mines). The species found were Otala lactea, Iberus gualterianus, Sphincterochila candidissima and Theba pisana. The D/L ratios of aspartic acid, leucine, phenylalanine and glutamic acid were determined, and the corresponding average age of each specimen was calculated introducing the D/L values in the age calculation algorithm of Torres et al. (1997) for gastropods of central and southern Spain. The racemization age for each locality was then compared to the radiometric age of the deposit where the specimens were collected. To this respect, the samples were classified in different groups considering the reliability on the age control method. The most reliable sample consists only on dates obtained by the radiocarbon method applied to pieces of charcoal found in the same sedimentary unit as the gastropod. The other subsets consider dates, or bracketed dates, obtained from other dating techniques (TL, OSL, Uranium series) or even stratigraphic criteria. Preliminary results show that Torres et al. (1997) calibration algorithm estimates ages as much as ten times older than the most likely one. We think that this result is due to a strong bias on the way the algorithm was obtained, based mostly in Lower Pleistocene/Pliocene samples. Hence, the new data presented here could be used to constraint better the Torres et al. (1997) function towards Upper Pleistocene and Holocene dates. This type of calibration model would be very valuable in determining ages of recent deposits in the Murcia Region, a matter that is critical in paleoseismological research.

  9. Post-glacial Slip History of The Sparta Fault (greece) Determined By Cosmogenic Dating: A New Technique For Tectonic and Seismic Hazard Studies

    NASA Astrophysics Data System (ADS)

    Benedetti, L.; King, G.; Finkel, R.; Papanastassiou, D.; Armijo, R.; Ryerson, F.; Farber, D.; Flerit, F.

    A major problem for understanding the active tectonics of the central and western Mediterranean region has been the inability to date geomorphic features in limestone. Recent advances in cosmogenic methods overcome this problem. The technique is relatively straight forward. Obtaining rates on numerous faults and related structures will not only improve our understanding of tectonic processes but will prove to be a major advance in establishing earthquake hazard. We illustrate the method by describ- ing continuous slip determinations at two places (10 km apart) on the Sparta normal fault scarp on which the great 464 BC earthquake was thought to have occurred. For a fault scarp, each major earthquake adds new surface exposing more rock to cosmic- ray bombardment. Using 36Cl cosmic ray exposure dating we obtained a continuous exposure history for the 7-12m-high limestone surfaces. The results confirm the hy- pothesis that the earthquake that destroyed ancient Sparta in 464 BC was on this fault. Four earlier earthquakes are also recorded at both sites in the last 13ka with similar slip amplitudes of about 2m and with time intervals ranging from 500yr to 4500yr. The observations confirm that the Sparta scarp is post-glacial, supporting the hypoth- esis that similar scarps elsewhere in the Mediterranean region have a similar age. The absence of any event since 464 BC could suggest a future event is imminent. However, the irregularity of earthquake time intervals could also be due to changes of loading with important consequences for the mechanics of continental deformation.

  10. Relative radiometric calibration of LANDSAT TM reflective bands

    NASA Technical Reports Server (NTRS)

    Barker, J. L.

    1984-01-01

    A common scientific methodology and terminology is outlined for characterizing the radiometry of both TM sensors. The magnitude of the most significant sources of radiometric variability are discussed and methods are recommended for achieving the exceptional potential inherent in the radiometric precision and accuracy of the TM sensors.

  11. Best practices for radiometric modeling of imaging spectrometers

    NASA Astrophysics Data System (ADS)

    Zellinger, Lou; Silny, John F.

    2015-09-01

    This paper provides best practices for the radiometric performance modeling of imaging spectrometers. A set of standard terminology is proposed to use when modeling imaging spectrometers. The calculation of various radiometric sensitivity metrics and their contrast counterparts are outlined. Modeling approaches are described for both solar reflected and thermally emitted bands. Finally, this approach is applied to an example hyperspectral sensor.

  12. A simple radiometric in vitro assay for acetylcholinesterase inhibitors

    SciTech Connect

    Guilarte, T.R.; Burns, H.D.; Dannals, R.F.; Wagner, H.N. Jr.

    1983-01-01

    A radiometric method for screening acetylcholinesterase inhibitors has been described. The method is based on the production of (/sup 14/C)carbon dioxide from the hydrolysis of acetylcholine. The inhibitory concentration at 50% (IC50) values for several known acetylcholinesterase inhibitors were in agreement with literature values. The new radiometric method is simple, inexpensive, and has the potential for automation.

  13. Rapid radiometric methods to detect and differentiate Mycobacterium tuberculosis/M. bovis from other mycobacterial species

    SciTech Connect

    Siddiqi, S.H.; Hwangbo, C.C.; Silcox, V.; Good, R.C.; Snider, D.E. Jr.; Middlebrook, G.

    1984-10-01

    Rapid methods for the differentiation of Mycobacterium tuberculosis/M. bovis (TB complex) from other mycobacteria (MOTT bacilli) were developed and evaluated in a three-phase study. In the first phase, techniques for identification of Mycobacterium species were developed by using radiometric technology and BACTEC Middlebrook 7H12 liquid medium. Based on /sup 14/CO/sub 2/ evolution, characteristic growth patterns were established for 13 commonly encountered mycobacterial species. Mycobacteria belonging to the TB complex were differentiated from other mycobacteria by cellular morphology and rate of /sup 14/CO/sub 2/ evolution. For further differentiation, radiometric tests for niacin production and inhibition by Q-nitro-alpha-acetyl amino-beta-hydroxy-propiophenone (NAP) were developed. In the second phase, 100 coded specimens on Lowenstein-Jensen medium were identified as members of the TB complex, MOTT bacilli, bacteria other than mycobacteria, or ''no viable organisms'' within 3 to 12 (average 6.4) days of receipt from the Centers for Disease Control. Isolation and identification of mycobacteria from 20 simulated sputum specimens were carried out in phase III. Out of 20 sputum specimens, 16 contained culturable mycobacteria, and all of the positives were detected by the BACTEC method in an average of 7.3 days. The positive mycobacterial cultures were isolated and identified as TB complex or MOTT bacilli in an average of 12.8 days. The radiometric NAP test was found to be highly sensitive and specific for a rapid identification of TB complex, whereas the radiometric niacin test was found to have some inherent problems. Radiometric BACTEC and conventional methodologies were in complete agreement in Phase II as well as in Phase III.

  14. A linear approach for radiometric calibration of full-waveform Lidar data

    NASA Astrophysics Data System (ADS)

    Roncat, Andreas; Pfeifer, Norbert; Briese, Christian

    2012-11-01

    During the past decade, small-footprint full-waveform lidar systems have become increasingly available, especially airborne. The primary output of these systems is high-resolution topographic information in the form of three-dimensional point clouds over large areas. Recording the temporal profile of the transmitted laser pulse and of its echoes enables to detect more echoes per pulse than in the case of discrete-return lidar systems, resulting in a higher point density over complex terrain. Furthermore, full-waveform instruments also allow for retrieving radiometric information of the scanned surfaces, commonly as an amplitude value and an echo width stored together with the 3D coordinates of the single points. However, the radiometric information needs to be calibrated in order to merge datasets acquired at different altitudes and/or with different instruments, so that the radiometric information becomes an object property independent of the flight mission and instrument parameters. State-of-the-art radiometric calibration techniques for full-waveform lidar data are based on Gaussian Decomposition to overcome the ill-posedness of the inherent inversion problem, i.e. deconvolution. However, these approaches make strong assumptions on the temporal profile of the transmitted laser pulse and the physical properties of the scanned surfaces, represented by the differential backscatter cross-section. In this paper, we present a novel approach for radiometric calibration using uniform B-splines. This kind of functions allows for linear inversion without constraining the temporal shape of the modeled signals. The theoretical derivation is illustrated by examples recorded with a Riegl LMS-Q560 and an Optech ALTM 3100 system, respectively.

  15. U-Pb dating of a speleothem of Quaternary age

    NASA Astrophysics Data System (ADS)

    Richards, David A.; Bottrell, Simon H.; Cliff, Robert A.; Strhle, Klaus; Rowe, Peter J.

    1998-12-01

    We demonstrate that U-Pb dating is a promising method for secondary carbonate materials of Quaternary age and older by obtaining a 206Pb?/ 238U age for a speleothem with high U (>10 ?g g -1) and very low Pb (<10 ng g -1) that is supported by an independent 230Th age. Thermal ionisation mass-spectrometry was used to determine the U and Pb isotopic ratios and concentrations for subsamples of a stalactite from Winnats Head Cave, Peak District, UK. We obtained 206Pb/ 204Pb ratios up to 50, and determined a 206Pb?/ 238U age of 248 10 ka, which is within error of the 207Pb?/ 235U age of 333 79 ka and a-spectrometric U-Th age of 255 ka. For samples of Tertiary and Quaternary age, the initial state of U-series disequilibrium is an important consideration and, as with most radiometric dating techniques, the mineral must have remained closed to U, Th, Pb, and all intermediate daughters. We show that dense calcite speleothems are ideal in this respect and that no loss of Rn has occurred. Unlike U-series disequilibrium methods, U-Pb dating has no upper limit and, hence, materials of Quaternary age older than 0.6 Ma can be analysed to investigate landscape development, paleoclimate, hominid evolution or hydrogeochemistry in carbonate terrains.

  16. Visible/infrared radiometric calibration station

    SciTech Connect

    Byrd, D.A.; Maier, W.B. II; Bender, S.C.; Holland, R.F.; Michaud, F.D.; Luettgen, A.L.; Christensen, R.W.; O`Brian, T.R.

    1994-07-01

    We have begun construction of a visible/infrared radiometric calibration station that will allow for absolute calibration of optical and IR remote sensing instruments with clear apertures less than 16 inches in diameter in a vacuum environment. The calibration station broadband sources will be calibrated at the National Institute of Standards and Technology (NIST) and allow for traceable absolute radiometric calibration to within {plus_minus}3% in the visible and near IR (0.4--2.5 {mu}m), and less than {plus_minus}1% in the infrared, up to 12 {mu}m. Capabilities for placing diffraction limited images or for sensor full-field flooding will exist. The facility will also include the calibration of polarization and spectral effects, spatial resolution, field of view performance, and wavefront characterization. The configuration of the vacuum calibration station consists of an off-axis 21 inch, f/3.2, parabolic collimator with a scanning fold flat in collimated space. The sources are placed, via mechanisms to be described, at the focal plane of the off-axis parabola. Vacuum system pressure will be in the 10{sup {minus}6} Torr range. The broadband white-light source is a custom design by LANL with guidance from Labsphere Inc. The continuous operating radiance of the integrating sphere will be from 0.0--0.006 W/cm{sup 2}/Sr/{mu}m (upper level quoted for {approximately}500 nm wavelength). The blackbody source is also custom designed at LANL with guidance from NIST. The blackbody temperature will be controllable between 250--350{degrees}K. Both of the above sources have 4.1 inch apertures with estimated radiometric instability at less than 1%. The designs of each of these units will be described. The monochromator and interferometer light sources are outside the vacuum, but all optical relay and beam shaping optics are enclosed within the vacuum calibration station. These sources are described, as well as the methodology for alignment and characterization.

  17. Radiometric resolution enhancement by lossy compression as compared to truncation followed by lossless compression

    NASA Technical Reports Server (NTRS)

    Tilton, James C.; Manohar, Mareboyana

    1994-01-01

    Recent advances in imaging technology make it possible to obtain imagery data of the Earth at high spatial, spectral and radiometric resolutions from Earth orbiting satellites. The rate at which the data is collected from these satellites can far exceed the channel capacity of the data downlink. Reducing the data rate to within the channel capacity can often require painful trade-offs in which certain scientific returns are sacrificed for the sake of others. In this paper we model the radiometric version of this form of lossy compression by dropping a specified number of least significant bits from each data pixel and compressing the remaining bits using an appropriate lossless compression technique. We call this approach 'truncation followed by lossless compression' or TLLC. We compare the TLLC approach with applying a lossy compression technique to the data for reducing the data rate to the channel capacity, and demonstrate that each of three different lossy compression techniques (JPEG/DCT, VQ and Model-Based VQ) give a better effective radiometric resolution than TLLC for a given channel rate.

  18. Relative Radiometric Normalization and Atmospheric Correction of a SPOT 5 Time Series

    PubMed Central

    Hajj, Mahmoud El; Bégué, Agnès; Lafrance, Bruno; Hagolle, Olivier; Dedieu, Gérard; Rumeau, Matthieu

    2008-01-01

    Multi-temporal images acquired at high spatial and temporal resolution are an important tool for detecting change and analyzing trends, especially in agricultural applications. However, to insure a reliable use of this kind of data, a rigorous radiometric normalization step is required. Normalization can be addressed by performing an atmospheric correction of each image in the time series. The main problem is the difficulty of obtaining an atmospheric characterization at a given acquisition date. In this paper, we investigate whether relative radiometric normalization can substitute for atmospheric correction. We develop an automatic method for relative radiometric normalization based on calculating linear regressions between unnormalized and reference images. Regressions are obtained using the reflectances of automatically selected invariant targets. We compare this method with an atmospheric correction method that uses the 6S model. The performances of both methods are compared using 18 images from of a SPOT 5 time series acquired over Reunion Island. Results obtained for a set of manually selected invariant targets show excellent agreement between the two methods in all spectral bands: values of the coefficient of determination (r2 exceed 0.960, and bias magnitude values are less than 2.65. There is also a strong correlation between normalized NDVI values of sugarcane fields (r2 = 0.959). Despite a relative error of 12.66% between values, very comparable NDVI patterns are observed.

  19. Virtual courseware for geoscience education: Virtual Earthquake and Virtual Dating

    NASA Astrophysics Data System (ADS)

    Novak, Gary A.

    1999-05-01

    Virtual courseware developed for introductory-level, on-line geology labs is an interactive teaching/learning model that has an enormous pedagogical potential for making Web sites places where students learn by doing. Virtual Earthquake and Virtual Dating are modest examples of the `virtual courseware' paradigm. Virtual Earthquake helps students explore the techniques of how an earthquake's epicenter is located and how its Richter magnitude is determined. Virtual Dating models the theory and techniques of the radiometric age determination of rocks and minerals. Virtual courseware applications offer several advantages over traditional floppy disk or CD ROM-based courseware, the most significant being the ease of dissemination. The author's experience with bringing these two virtual applications on-line suggests that there is a need for interactive geology labs on-line and that the approach will be received with enthusiasm by the educational community. The widespread implementation and adoption of virtual courseware can bring meaningful educational content and interactivity for the geosciences that goes beyond multimedia on the World-Wide-Web.

  20. System implications of large radiometric array antennas

    NASA Technical Reports Server (NTRS)

    Levis, C. A.; Lin, H. C.

    1976-01-01

    Current radiometric earth and atmospheric sensing systems in the centimeter wavelength range generally employ a directive antenna connected through a single terminal pair to a Dicke receiver. It is shown that this approach does not lend itself to systems with greatly increased spatial resolution. Signal to noise considerations relating to antenna efficiency force the introduction of active elements at the subarray level; thus, if Dicke switching is to be used, it must be distributed throughout the system. Some possible approaches are suggested. The introduction of active elements at the subarray level is found to ease the design constraints on time delay elements, necessary for bandwidth, and on multiple beam generation, required in order to achieve sufficient integration time with high resolution.

  1. Radiometrically accurate FTS for atmospheric emission observations

    NASA Technical Reports Server (NTRS)

    Revercomb, H. E.; Smith, W. L.; Stromovsky, L. A.; Knuteson, R. O.; Buijs, H.

    1989-01-01

    The calibration and operational performance of an FTIR-based airborne high-resolution interferometer sounder (HIS) for use in broadband measurements of atmospheric emission at 3.8-16.6 microns are described. The radiometric and wavelength calibration procedures in the laboratory involved the use of reference black bodies at 300 and 245 K and the known wavelength of the HIS HeNe laser (corrected for FOV effects), respectively. The atmospheric verification program included downlooking observations from the NASA U2/ER2 aircraft (where resolving power of 1800-3800 was demonstrated) and uplooking observations from the ground; good agreement with data from balloon-borne radiosondes is obtained, with absolute temperature uncertainties of less than 0.5 K and reproducibilities of 0.1-0.2 K over most of the measurement domain.

  2. GIFTS SM EDU Radiometric and Spectral Calibrations

    NASA Technical Reports Server (NTRS)

    Tian, J.; Reisse, R. a.; Johnson, D. G.; Gazarik, J. J.

    2007-01-01

    The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiance using a Fourier transform spectrometer (FTS). The GIFTS instrument gathers measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the processing algorithms involved in the calibration. The calibration procedures can be subdivided into three categories: the pre-calibration stage, the calibration stage, and finally, the post-calibration stage. Detailed derivations for each stage are presented in this paper.

  3. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-11-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  4. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-07-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark datasets for both inter-calibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and -B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through one year of simultaneous nadir overpass (SNO) observations to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the longwave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both Polar and Tropical SNOs. The combined global SNO datasets indicate that, the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 comparison spectral regions and they range from 0.15 to 0.21 K in the remaining 4 spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  5. Absolute Radiometric Calibration of EUNIS-06

    NASA Technical Reports Server (NTRS)

    Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.

    2007-01-01

    The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.

  6. Landsat-7 ETM+ radiometric stability and absolute calibration

    USGS Publications Warehouse

    Markham, B.L.; Barker, J.L.; Barsi, J.A.; Kaita, E.; Thome, K.J.; Helder, D.L.; Palluconi, Frank Don; Schott, J.R.; Scaramuzza, P.

    2002-01-01

    Launched in April 1999, the Landsat-7 ETM+ instrument is in its fourth year of operation. The quality of the acquired calibrated imagery continues to be high, especially with respect to its three most important radiometric performance parameters: reflective band instrument stability to better than ??1%, reflective band absolute calibration to better than ??5%, and thermal band absolute calibration to better than ??0.6 K. The ETM+ instrument has been the most stable of any of the Landsat instruments, in both the reflective and thermal channels. To date, the best on-board calibration source for the reflective bands has been the Full Aperture Solar Calibrator, which has indicated changes of at most -1.8% to -2.0% (95% C.I.) change per year in the ETM+ gain (band 4). However, this change is believed to be caused by changes in the solar diffuser panel, as opposed to a change in the instrument's gain. This belief is based partially on ground observations, which bound the changes in gain in band 4 at -0.7% to +1.5%. Also, ETM+ stability is indicated by the monitoring of desert targets. These image-based results for four Saharan and Arabian sites, for a collection of 35 scenes over the three years since launch, bound the gain change at -0.7% to +0.5% in band 4. Thermal calibration from ground observations revealed an offset error of +0.31 W/m 2 sr um soon after launch. This offset was corrected within the U. S. ground processing system at EROS Data Center on 21-Dec-00, and since then, the band 6 on-board calibration has indicated changes of at most +0.02% to +0.04% (95% C.I.) per year. The latest ground observations have detected no remaining offset error with an RMS error of ??0.6 K. The stability and absolute calibration of the Landsat-7 ETM+ sensor make it an ideal candidate to be used as a reference source for radiometric cross-calibrating to other land remote sensing satellite systems.

  7. Landsat-7 EMT+ On-Orbit Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Markham, Brian L.; Barker, J. L.; Kaita, E.; Seiferth, J.; Morfitt, Ron

    1999-01-01

    Landsat-7 was launched on April 15, 1999 and completed its on orbit initialization and verification period on June 28, 1999. The ETM+ payload is similar to the TM sensors on previous Landsat satellites and incorporates two new devices to improve its absolute radiometric calibration. The Full Aperture Solar Calibrator (FASC) is a deployable diffuser panel. This device has been deployed 9 times to date, with a normal deployment schedule of once per month. The initial analysis of the FASC data has given absolute calibration results within 5% of the prelaunch integrating sphere calibrations and a range of variation of 2% between dates. The Partial Aperture Solar Calibrator (PASC), is a set of auxiliary optics that allows the ETM+ to view the sun through a reduced aperture. Data have normally been acquired on a daily basis with the PASC. Initial results with the PASC were encouraging, despite some unexpected saturation in the shortest wavelength band. The response of the ETM+ short wavelength (silicon) bands to the PASC increased initially and has begun to decrease in some of these bands. The longer wavelength (InSb) bands have shown up to 30% oscillations that vary between detectors within the band. Studies are ongoing to better characterize the response to the PASC. The ETM+ also incorporates an internal calibrator (IC), a shutter that oscillates in front of the focal plane that directs light from the internal calibrator lamps to the focal plane. The responses to this device are also varying, though differently than the PASC results. Both the IC and PASC results are attributable to the calibration devices as opposed to the ETM+ itself.

  8. Errors in radiometric remote sensing of sea-surface temperature and salinity

    NASA Technical Reports Server (NTRS)

    Britt, C. L., Jr.

    1984-01-01

    Techniques for remote measurement of sea-surface physical temperature and salinity using radiometric measurements from aircraft or satellite are reviewed. Studies have been conducted to determine the sensitivity of the errors in surface temperature and salinity to errors in the measured brightness temperatures using combinations of UHF, L, S, and C-band measurements. These investigations were made using values of conductivity, static dielectric constant, and relaxation time derived from the regression equations of Klein and Swift (1977). Results of the error sensitivity study are presented in the form of error contour plots which permit the calculation of errors in the estimation of the physical parameters for given errors in the raw radiometric measurements.

  9. Oxygen isotope studies and compilation of isotopic dates from Antarctica

    SciTech Connect

    Grootes, P.M.; Stuiver, M.

    1986-01-01

    The Quaternary Isotope Laboratory, alone or in collaboration with other investigators, is currently involved in a number of oxygen-isotope studies mainly in Antarctica. Studies of a drill core from the South Pole, seasonal oxygen-18 signals preserved in the Dominion Range, isotope dating of the Ross Ice Shelf, oxygen-18 profiles of the Siple Coast, McMurdo Ice Shelf sampling, and a data compilation of radiometric dates from Antarctica are discussed.

  10. Radiometric detection of yeasts in blood cultures of cancer patients

    SciTech Connect

    Hopfer, R.L.; Orengo, A.; Chesnut, S.; Wenglar, M.

    1980-09-01

    During a 12-month period, 19,457 blood cultures were collected. Yeasts were isolated from 193 cultures derived from 76 cancer patients. Candida albicans or Candida tropicalis accounted for 79% of isolates. Of the three methods compared, the radiometric method required 2.9 days to become positive, blind subculture required 2.6 days, and Gram stains required 1 day. However, the radiometric method was clearly superior in detecting positive cultures, since 73% of all cultures were first detected radiometrically, 22% were detected by subculture, and only 5% were detected by Gram stain. Although 93% of the isolates were detected by aerobic culture, five (7%) isolates were obtained only from anaerobic cultures. Seven days of incubation appear to be sufficient for the radiometric detection of yeasts.

  11. Radium decay series dating of barite deposition in the Gulf of Mexico: Initial results

    SciTech Connect

    Van Gent, D.L.; Scott, L.M.; Fu, B.

    1995-12-31

    Barite deposits consisting of chimneys and crusts were recently documented and recovered by submersible from hydrocarbon seeps in the Gulf of Mexico offshore Louisiana at water depths of 510-670 m in the Garden Banks and Mississippi Canyon areas. This is the first discovery of barite deposits associated with cold hydrocarbon seeps. The outer part of the chimneys are dominated by barite whereas the inner part of the chimneys are dominated by barite with pyrite as accessory mineral. The crusts are about 5-8 cm thick and their surficial layers are composed of barite coexisting with carbonate whereas the lower part of the crusts consists of barite, carbonate, and pyrite. A program of radiometric dating by Ra decay series isotopes was initiated in order to derive a chronology of barite deposition in association with the hydrocarbon seeps. Chimneys and crusts were analyzed for NORM using a high purity intrinsic germanium gamma spectroscopy system. The deposits were found to contain {sup 226}Ra and {sup 228}Ra at concentrations comparable to those found in scale associated with oil production in the Gulf States Region (approximately 500 pCi/gm and 250 pCi/gm, respectively). The deposits were subjected to two separate age dating techniques. The primary technique utilized gamma spectroscopy for determination of {sup 210}Pb/{sup 226}Ra ratios. The second technique utilized gamma spectroscopy for determination of {sup 226}Th/{sup 228}Ra ratios. Ages as determined by {sup 210}Pb/{sup 226}Ra ranged from 2 years to 40 years. The {sup 228}Th/{sup 228}Ra methodology tended to validate the primary dating technique, although the useful range of dating for this method does not exceed 15 years. Sulfide-rich layers in the barite deposits tended to give anomalous and biased results when dated by the primary method. Both methodologies also appear valid for age dating scale deposits {le} 100 years old that are generated in oil production operations.

  12. Blast investigation by fast multispectral radiometric analysis

    NASA Astrophysics Data System (ADS)

    Devir, A. D.; Bushlin, Y.; Mendelewicz, I.; Lessin, A. B.; Engel, M.

    2011-06-01

    Knowledge regarding the processes involved in blasts and detonations is required in various applications, e.g. missile interception, blasts of high-explosive materials, final ballistics and IED identification. Blasts release large amount of energy in short time duration. Some part of this energy is released as intense radiation in the optical spectral bands. This paper proposes to measure the blast radiation by a fast multispectral radiometer. The measurement is made, simultaneously, in appropriately chosen spectral bands. These spectral bands provide extensive information on the physical and chemical processes that govern the blast through the time-dependence of the molecular and aerosol contributions to the detonation products. Multi-spectral blast measurements are performed in the visible, SWIR and MWIR spectral bands. Analysis of the cross-correlation between the measured multi-spectral signals gives the time dependence of the temperature, aerosol and gas composition of the blast. Farther analysis of the development of these quantities in time may indicate on the order of the detonation and amount and type of explosive materials. Examples of analysis of measured explosions are presented to demonstrate the power of the suggested fast multispectral radiometric analysis approach.

  13. Radiometric sensitivity comparisons of multispectral imaging systems

    NASA Technical Reports Server (NTRS)

    Lu, Nadine C.; Slater, Philip N.

    1989-01-01

    Multispectral imaging systems provide much of the basic data used by the land and ocean civilian remote-sensing community. There are numerous multispectral imaging systems which have been and are being developed. A common way to compare the radiometric performance of these systems is to examine their noise-equivalent change in reflectance, NE Delta-rho. The NE Delta-rho of a system is the reflectance difference that is equal to the noise in the recorded signal. A comparison is made of the noise equivalent change in reflectance of seven different multispectral imaging systems (AVHRR, AVIRIS, ETM, HIRIS, MODIS-N, SPOT-1, HRV, and TM) for a set of three atmospheric conditions (continental aerosol with 23-km visibility, continental aerosol with 5-km visibility, and a Rayleigh atmosphere), five values of ground reflectance (0.01, 0.10, 0.25, 0.50, and 1.00), a nadir viewing angle, and a solar zenith angle of 45 deg.

  14. The Radiometric Bode's Law and Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Lazio, T. Joseph, W.; Farrell, W. M.; Dietrick, Jill; Greenlees, Elizabeth; Hogan, Emily; Jones, Christopher; Hennig, L. A.

    2004-09-01

    We predict the radio flux densities of the extrasolar planets in the current census, making use of an empirical relation-the radiometric Bode's law-determined from the five ``magnetic'' planets in the solar system (the Earth and the four gas giants). Radio emission from these planets results from solar wind-powered electron currents depositing energy in the magnetic polar regions. We find that most of the known extrasolar planets should emit in the frequency range 10-1000 MHz and, under favorable circumstances, have typical flux densities as large as 1 mJy. We also describe an initial, systematic effort to search for radio emission in low radio frequency images acquired with the Very Large Array (VLA). The limits set by the VLA images (~300 mJy) are consistent with, but do not provide strong constraints on, the predictions of the model. Future radio telescopes, such as the Low Frequency Array and the Square Kilometer Array, should be able to detect the known extrasolar planets or place austere limits on their radio emission. Planets with masses much lower than those in the current census will probably radiate below 10 MHz and will require a space-based array.

  15. A radiometric assay for HIV-1 protease

    SciTech Connect

    Hyland, L.J.; Dayton, B.D.; Moore, M.L.; Shu, A.Y.; Heys, J.R.; Meek, T.D. )

    1990-08-01

    A rapid, high-throughput radiometric assay for HIV-1 protease has been developed using ion-exchange chromatography performed in 96-well filtration plates. The assay monitors the activity of the HIV-1 protease on the radiolabeled form of a heptapeptide substrate, (tyrosyl-3,5-3H)Ac-Ser-Gln-Asn-Tyr-Pro-Val-Val-NH2, which is based on the p17-p24 cleavage site found in the viral polyprotein substrate Pr55gag. Specific cleavage of this uncharged heptapeptide substrate by HIV-1 protease releases the anionic product (tyrosyl-3,5-3H)Ac-Ser-Gln-Asn-Tyr, which is retained upon minicolumns of the anion-exchange resin AG1-X8. Protease activity is determined from the recovery of this radiolabeled product following elution with formic acid. This facile and highly sensitive assay may be utilized for steady-state kinetic analysis of the protease, for measurements of enzyme activity during its purification, and as a routine assay for the evaluation of protease inhibitors from natural product or synthetic sources.

  16. Calibrated infrared ground/air radiometric spectrometer

    NASA Astrophysics Data System (ADS)

    Silk, J. K.; Schildkraut, Elliot Robert; Bauldree, Russell S.; Goodrich, Shawn M.

    1996-06-01

    The calibrated infrared ground/air radiometric spectrometer (CIGARS) is a new high performance, multi-purpose, multi- platform Fourier transform spectrometer (FPS) sensor. It covers the waveband from 0.2 to 12 micrometer, has spectral resolution as fine as 0.3 cm-1, and records over 100 spectra per second. Two CIGARS units are being used for observations of target signatures in the air or on the ground from fixed or moving platforms, including high performance jet aircraft. In this paper we describe the characteristics and capabilities of the CIGARS sensor, which uses four interchangeable detector modules (Si, InGaAs, InSb, and HgCdTe) and two optics modules, with internal calibration. The data recording electronics support observations of transient events, even without precise information on the timing of the event. We present test and calibration data on the sensitivity, spectral resolution, stability, and spectral rate of CIGARS, and examples of in- flight observations of real targets. We also discuss plans for adapting CIGARS for imaging spectroscopy observations, with simultaneous spectral and spatial data, by replacing the existing detectors with a focal plane array (FPA).

  17. Phoretic and Radiometric Force Measurements on Microparticles in Microgravity Conditions

    NASA Technical Reports Server (NTRS)

    Davis, E. James

    1996-01-01

    Thermophoretic, diffusiophoretic and radiometric forces on microparticles are being measured over a wide range of gas phase and particle conditions using electrodynamic levitation of single particles to simulate microgravity conditions. The thermophoretic force, which arises when a particle exists in a gas having a temperature gradient, is measured by levitating an electrically charged particle between heated and cooled plates mounted in a vacuum chamber. The diffusiophoretic force arising from a concentration gradient in the gas phase is measured in a similar manner except that the heat exchangers are coated with liquids to establish a vapor concentration gradient. These phoretic forces and the radiation pressure force acting on a particle are measured directly in terms of the change in the dc field required to levitate the particle with and without the force applied. The apparatus developed for the research and the experimental techniques are discussed, and results obtained by thermophoresis experiments are presented. The determination of the momentum and energy accommodation coefficients associated with molecular collisions between gases molecules and particles and the measurement of the interaction between electromagnetic radiation and small particles are of particular interest.

  18. Principal component noise filtering for NAST-I radiometric calibration

    NASA Astrophysics Data System (ADS)

    Tian, Jialin; Smith, William L., Sr.

    2011-11-01

    The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed- Interferometer (NAST-I) instrument is a high-resolution scanning interferometer that measures emitted thermal radiation between 3.3 and 18 microns. The NAST-I radiometric calibration is achieved using internal blackbody calibration references at ambient and hot temperatures. In this paper, we introduce a refined calibration technique that utilizes a principal component (PC) noise filter to minimize the impact of measurement noise on the calibration of Earth scene radiance spectra. To test the procedure and estimate the PC filter noise performance, we form dependent and independent test samples using odd and even sets of blackbody spectra. To determine the optimal number of eigenvectors, the PC filter algorithm is applied to both dependent and independent blackbody spectra with a varying number of eigenvectors. The optimal number of PCs is selected so that the total root-mean-square (RMS) error of the calibrated reference scene blackbody data is minimized. To estimate the filter noise performance, we examine four different scenarios: apply PC filtering to both dependent and independent datasets, apply PC filtering to dependent calibration data only, apply PC filtering to independent data only, and no PC filtering. The independent blackbody radiances are predicted for each case and comparisons are made. The results show significant reduction in noise in the final calibrated scene radiances with the implementation of the PC filtering algorithm.

  19. Radiometric Calibration of High Resolution UAVSAR Data Using Low Resolution SRTM DEMs

    NASA Astrophysics Data System (ADS)

    Riel, B. V.; Simard, M.

    2010-12-01

    Airborne and spaceborne Synthetic Aperture Radar (SAR) backscatter data have the potential to retrieve information on forest structure, above-ground biomass, and moisture content. However, SAR backscatter data contain both geometric and radiometric distortions due to underlying topography and the radar viewing geometry. These distortions can significantly affect the estimation of various scientific quantities. For example, a backscatter error of 1 dB can result in a biomass estimation error on the order of 10-15 Mg/ha. Thus, science applications based on SAR backscatter require accurate absolute radiometric calibration. The calibration process for topography involves estimation of the local radar scattering area through knowledge of the imaged terrain, which is often obtained through digital elevation models (DEMs). For this study, we radiometrically calibrate high resolution UAVSAR L-band radar data over a temperate forest site in New Hampshire using a low resolution (30m) SRTM DEM. Different calibration methods were tested and compared. We found that homomorphic methods based on the local incidence or projection angle do not estimate the scattering area as well as heteromorphic methods utilizing DEM integration techniques. Errors in the area estimation resulted in calibration differences less than 0.5 dB. The impact of low DEM resolution on calibration performance was assessed using a Fourier analysis of a large range of topographic classes. Power spectra were computed for high-resolution, bare-earth airborne lidar DEMs acquired over steep, moderate, and flat terrain. Similar power spectra were computed for oversampled SRTM DEMs over the same terrain. Errors for an SRTM DEM associated with a particular topographic class could be quantified through a comparison of its power spectrum with that from the lidar. We present a Fourier based method to systematically propagate errors in slope and aspect estimations to radiometric calibration accuracy. The methodology was validated by comparing slope and aspect derived from SRTM and lidar DEMs.

  20. Impact of the cameras radiometric resolution on the accuracy of determining spectral reflectance coefficients

    NASA Astrophysics Data System (ADS)

    Orych, A.; Walczykowski, P.; Jenerowicz, A.; Zdunek, Z.

    2014-11-01

    Nowadays remote sensing plays a very important role in many different study fields, i.e. environmental studies, hydrology, mineralogy, ecosystem studies, etc. One of the key areas of remote sensing applications is water quality monitoring. Understanding and monitoring of the water quality parameters and detecting different water contaminants is an important issue in water management and protection of whole environment and especially the water ecosystem. There are many remote sensing methods to monitor water quality and detect water pollutants. One of the most widely used method for substance detection with remote sensing techniques is based on usage of spectral reflectance coefficients. They are usually acquired using discrete methods such as spectrometric measurements. These however can be very time consuming, therefore image-based methods are used more and more often. In order to work out the proper methodology of obtaining spectral reflectance coefficients from hyperspectral and multispectral images, it is necessary to verify the impact of cameras radiometric resolution on the accuracy of determination of them. This paper presents laboratory experiments that were conducted using two monochromatic XEVA video sensors (400-1700 nm spectral data registration) with two different radiometric resolutions (12 and 14 bits). In view of determining spectral characteristics from images, the research team used set of interferometric filters. All data collected with multispectral digital video cameras were compared with spectral reflectance coefficients obtained with spectroradiometer. The objective of this research is to find the impact of cameras radiometric resolution on reflectance values in chosen wavelength. The main topic of this study is the analysis of accuracy of spectral coefficients from sensors with different radiometric resolution. By comparing values collected from images acquired with XEVA sensors and with the curves obtained with spectroradiometer it's possible to determine accuracy of imagebased spectral reflectance coefficients and decide which sensor will be more accurate to determine them for protection of water aquatic environment purpose.

  1. Luminescence dating and palaeomagnetic age constraint on hominins from Sima de los Huesos, Atapuerca, Spain.

    PubMed

    Arnold, Lee J; Demuro, Martina; Pars, Josep M; Arsuaga, Juan Luis; Aranburu, Arantza; Bermdez de Castro, Jos Mara; Carbonell, Eudald

    2014-02-01

    Establishing a reliable chronology on the extensive hominin remains at Sima de los Huesos is critical for an improved understanding of the complex evolutionary histories and phylogenetic relationships of the European Middle Pleistocene hominin record. In this study, we use a combination of 'extended-range' luminescence dating techniques and palaeomagnetism to provide new age constraint on sedimentary infills that are unambiguously associated with the Sima fossil assemblage. Post-infrared-infrared stimulated luminescence (pIR-IR) dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains provide weighted mean ages of 43315ka (thousands of years) and 41619ka, respectively, for allochthonous sedimentary horizons overlying the hominin-bearing clay breccia. The six replicate luminescence ages obtained for this deposit are reproducible and provide a combined minimum age estimate of 42712ka for the underlying hominin fossils. Palaeomagnetic directions for the luminescence dated sediment horizon and underlying fossiliferous clays display exclusively normal polarities. These findings are consistent with the luminescence dating results and confirm that the hominin fossil horizon accumulated during the Brunhes Chron, i.e., within the last 780ka. The new bracketing age constraint for the Sima hominins is in broad agreement with radiometrically dated Homo heidelbergensis fossil sites, such as Mauer and Arago, and suggests that the split of the H.neanderthalensis and H.sapiens lineages took place during the early Middle Pleistocene. More widespread numerical dating of key Early and Middle Pleistocene fossil sites across Europe is needed to test and refine competing models of hominin evolution. The new luminescence chronologies presented in this study demonstrate the versatility of TT-OSL and pIR-IR techniques and the potential role they could play in helping to refine evolutionary histories over Middle Pleistocene timescales. PMID:24485349

  2. Relative Dating Via Fractures

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    This VIS image of the eastern part of the Tharsis region illustrates how fractures can be used in relative dating of a surface. The fractured materials on the right side of the image are embayed by younger volcanic flows originating to the west of the image. Note how the younger flows cover the ends of the fractures, and are not at all fractured themselves.

    Image information: VIS instrument. Latitude 43.2, Longitude 269.4 East (90.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Thermochronology of economic mineral deposits: dating the stages of mineralization at Panasqueira, Portugal, by high-precision 40Ar/ 39Ar age spectrum techniques on muscovite

    USGS Publications Warehouse

    Snee, L.W.; Sutter, J.F.; Kelly, W.C.

    1988-01-01

    This study is an example of a new and powerful application of 40Ar/39Ar age spectrum dating of muscovite. It is now possible to establish time constraints necessary for solving some of the long-standing problems in economic geology. Beyond this, the unique geologic situation of Panasqueira has allowed us to quantify the thermal characteristics of muscovite. Published fluid inclusion data have been used to estimate a muscovite argon closure temperature of ~325??C during rapid cooling or short reheating and a temperature of ~270??C during slow cooling or extended reheating. Argon-loss patterns displayed by all dated muscovites resulted from reheating after original closure; the mechanism for this argon loss appears to have been argon transport by volume diffusion. Thus, 40Ar/39Ar age spectrum dating of muscovite can be used to evaluate thermal conditions controlling argon diffusion as well as age, duration, and number of episodes of mineralization. -from Authors

  4. Conjugate Cassegrain telescopes for thermal source FTIR spectral radiometric calibration

    NASA Astrophysics Data System (ADS)

    Wolk, Martin; McGillicuddy, Robert J.; Zurlinden, Joseph E.

    1998-08-01

    Two Cassegrain telescopes were constructed to function as sender and receiver for an FTIR spectrometer primarily for the purpose of obtaining spectral data for analysis of military night vision emission targets, and spectral calibration of external variable temperature thermal radiation sources, utilizing freezing-point type blackbodies for primary radiation temperature standards. The sender and receiver telescopes, F/7 and F/5, respectively, each employ 0.30 m (12 in) diameter primary and 0.15 m (6 in) diameter secondary, protected Ag coated Zerodur mirrors. In operation, a thermal target image formed by the sender, whose optical axis is aligned with that of the receiver and spectrometer, is transmitted to and brought to a focus at the spectrometer entrance aperture by the receiver telescope. With (lambda) /8 p-v optical surface accuracy at 633 nm, telescope system tests indicate near diffraction- limited performance in the visible, and 2.81 mrad (full) FOV with further reduction achieved with field stops. Wavelength range capability of the commercially available FTIR instrument employed is approximately 0.22 micrometers (55000 cm-1) to 22 micrometers (450 cm-1) with wavenumber resolution of about 0.013 cm-1 in the IR to 0.769 micrometers (13000 cm-1). In this paper, the techniques and tests employed for the telescope mirror construction are described. An innovative technique for secondary alignment for Hindle's tests of a Cassegrain utilizing a He-Ne laser is presented. Telescope mountings for positioning and alignment with the FTIR are briefly discussed, as well as radiometric and calibration parameters for the integrated system.

  5. Absolute Radiometric Calibration of Narrow-Swath Imaging Sensors with Reference to Non-Coincident Wide-Swath Sensors

    NASA Technical Reports Server (NTRS)

    McCorkel, Joel; Thome, Kurtis; Lockwood, Ronald

    2012-01-01

    An inter-calibration method is developed to provide absolute radiometric calibration of narrow-swath imaging sensors with reference to non-coincident wide-swath sensors. The method predicts at-sensor radiance using non-coincident imagery from the reference sensor and knowledge of spectral reflectance of the test site. The imagery of the reference sensor is restricted to acquisitions that provide similar view and solar illumination geometry to reduce uncertainties due to directional reflectance effects. Spectral reflectance of the test site is found with a simple iterative radiative transfer method using radiance values of a well-understood wide-swath sensor and spectral shape information based on historical ground-based measurements. At-sensor radiance is calculated for the narrow-swath sensor using this spectral reflectance and atmospheric parameters that are also based on historical in situ measurements. Results of the inter-calibration method show agreement on the 2 5 percent level in most spectral regions with the vicarious calibration technique relying on coincident ground-based measurements referred to as the reflectance-based approach. While the variability of the inter-calibration method based on non-coincident image pairs is significantly larger, results are consistent with techniques relying on in situ measurements. The method is also insensitive to spectral differences between the sensors by transferring to surface spectral reflectance prior to prediction of at-sensor radiance. The utility of this inter-calibration method is made clear by its flexibility to utilize image pairings with acquisition dates differing in excess of 30 days allowing frequent absolute calibration comparisons between wide- and narrow-swath sensors.

  6. Deep Space Network Radiometric Remote Sensing Program

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.

    1994-01-01

    Planetary spacecraft are viewed through a troposphere that absorbs and delays radio signals propagating through it. Tropospheric water, in the form of vapor, cloud liquid, and precipitation, emits radio noise which limits satellite telemetry communication link performance. Even at X-band, rain storms have severely affected several satellite experiments including a planetary encounter. The problem will worsen with DSN implementation of Ka-band because communication link budgets will be dominated by tropospheric conditions. Troposphere-induced propagation delays currently limit VLBI accuracy and are significant sources of error for Doppler tracking. Additionally, the success of radio science programs such as satellite gravity wave experiments and atmospheric occultation experiments depends on minimizing the effect of water vapor-induced propagation delays. In order to overcome limitations imposed by the troposphere, the Deep Space Network has supported a program of radiometric remote sensing. Currently, water vapor radiometers (WVRs) and microwave temperature profilers (MTPs) support many aspects of the Deep Space Network operations and research and development programs. Their capability to sense atmospheric water, microwave sky brightness, and atmospheric temperature is critical to development of Ka-band telemetry systems, communication link models, VLBI, satellite gravity wave experiments, and radio science missions. During 1993, WVRs provided data for propagation model development, supported planetary missions, and demonstrated advanced tracking capability. Collection of atmospheric statistics is necessary to model and predict performance of Ka-band telemetry links, antenna arrays, and radio science experiments. Since the spectrum of weather variations has power at very long time scales, atmospheric measurements have been requested for periods ranging from one year to a decade at each DSN site. The resulting database would provide reliable statistics on daily, monthly, and seasonal variations. Only long-term monitoring will prevent biases from being introduced by an exceptionally wet or dry year. Support for planetary missions included tropospheric calibration for the recent Mars Observer gravity wave experiments and Ka-band link experiment (KaBLE). Additionally, several proposed radio science experiments such as profiling planetary atmospheres using satellite occultations and Ka-band gravitational wave searches require advanced radiometer technology development. Finally, there has been a consistent advanced technology program to advance satellite navigational and tracking capabilities. This year that included an experiment with radiometer based tropospheric calibration for a series of VLBI catalog measurements.

  7. New classes of radiometric and combined radiometric-geometric invariant descriptors.

    PubMed

    Metari, Samy; Deschnes, Franois

    2008-06-01

    Real images can contain geometric distortions as well as photometric degradations. Analysis and characterization of those images without recourse to either restoration or geometric standardization is of great importance for the computer vision community as those two processes are often ill-posed problems. To this end, it is necessary to implement image descriptors that make it possible to identify the original image in a simple way independently of the imaging system and imaging conditions. Ideally, descriptors that capture image characteristics must be invariant to the whole range of geometric distortions and photometric degradations, such as blur, that may affect the image. In this paper, we introduce two new classes of radiometric and/or geometric invariant descriptors. The first class contains two types of radiometric invariant descriptors. The first of these type is based on the Mellin transform and the second one is based on central moments. Both descriptors are invariant to contrast changes and to convolution with any kernel having a symmetric form with respect to the diagonals. The second class contains two subclasses of combined invariant descriptors. The first subclass includes central-moment-based descriptors invariant simultaneously to horizontal and vertical translations, to uniform and anisotropic scaling, to stretching, to convolution, and to contrast changes. The second subclass contains central-complex-moment-based descriptors that are simultaneously invariant to similarity transformation and to contrast changes. We apply these invariant descriptors to the matching of geometric transformed and/or blurred images. Experimental results confirm both the robustness and the effectiveness of the proposed invariants. PMID:18482893

  8. A Kalman Approach to Lunar Surface Navigation using Radiometric and Inertial Measurements

    NASA Technical Reports Server (NTRS)

    Chelmins, David T.; Welch, Bryan W.; Sands, O. Scott; Nguyen, Binh V.

    2009-01-01

    Future lunar missions supporting the NASA Vision for Space Exploration will rely on a surface navigation system to determine astronaut position, guide exploration, and return safely to the lunar habitat. In this report, we investigate one potential architecture for surface navigation, using an extended Kalman filter to integrate radiometric and inertial measurements. We present a possible infrastructure to support this technique, and we examine an approach to simulating navigational accuracy based on several different system configurations. The results show that position error can be reduced to 1 m after 5 min of processing, given two satellites, one surface communication terminal, and knowledge of the starting position to within 100 m.

  9. In Situ Radiometric and Exposure Age Dating of the Martian Surface

    NASA Astrophysics Data System (ADS)

    Farley, K. A.; Malespin, C.; Mahaffy, P.; Grotzinger, J. P.; Vasconcelos, P. M.; Milliken, R. E.; Malin, M.; Edgett, K. S.; Pavlov, A. A.; Hurowitz, J. A.; Grant, J. A.; Miller, H. B.; Arvidson, R.; Beegle, L.; Calef, F.; Conrad, P. G.; Dietrich, W. E.; Eigenbrode, J.; Gellert, R.; Gupta, S.; Hamilton, V.; Hassler, D. M.; Lewis, K. W.; McLennan, S. M.; Ming, D.; Navarro-Gonzlez, R.; Schwenzer, S. P.; Steele, A.; Stolper, E. M.; Sumner, D. Y.; Vaniman, D.; Vasavada, A.; Williford, K.; Wimmer-Schweingruber, R. F.; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Dworkin, Jason P.; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Martin, David K.; McAdam, Amy; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Behar, Alberto; Blaney, Diana; Brinza, David; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Williams, Rebecca M. E.; Yingst, Aileen; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhs, Grard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernndez, Miguel ngel de Pablo; valos, Juan Jos Blanco; Ramos, Miguel; Kim, Myung-Hee; Plante, Ianik; Muller, Jan-Peter; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Kortmann, Onno; Palucis, Marisa; Williams, Amy; Lugmair, Gnter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Klvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Savijrvi, Hannu; Boehm, Eckart; Bttcher, Stephan; Burmeister, Snke; Guo, Jingnan; Khler, Jan; Garca, Csar Martn; Mueller-Mellin, Reinhold; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Renn, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2014-01-01

    We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced 3He, 21Ne, and 36Ar yield concordant surface exposure ages of 78 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.

  10. In situ radiometric and exposure age dating of the martian surface.

    PubMed

    Farley, K A; Malespin, C; Mahaffy, P; Grotzinger, J P; Vasconcelos, P M; Milliken, R E; Malin, M; Edgett, K S; Pavlov, A A; Hurowitz, J A; Grant, J A; Miller, H B; Arvidson, R; Beegle, L; Calef, F; Conrad, P G; Dietrich, W E; Eigenbrode, J; Gellert, R; Gupta, S; Hamilton, V; Hassler, D M; Lewis, K W; McLennan, S M; Ming, D; Navarro-González, R; Schwenzer, S P; Steele, A; Stolper, E M; Sumner, D Y; Vaniman, D; Vasavada, A; Williford, K; Wimmer-Schweingruber, R F

    2014-01-24

    We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced (3)He, (21)Ne, and (36)Ar yield concordant surface exposure ages of 78 ± 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation. PMID:24324273

  11. In Situ Radiometric Dating of Aqueously Formed Carbonates in Sutter's Mill

    NASA Astrophysics Data System (ADS)

    Jilly, C. E.; Huss, G. R.; Nagashima, K.; Yin, Q.-Z.; Sugiura, N.; Krot, A. N.

    2013-09-01

    We report Manganese-Chromium systematics for dolomite grains in the Sutter's Mill meteorite, section SM-51. Measurements yield a well-defined isochron with aqueous alteration ages comparable to CM and CI chondrites.

  12. New radiometric dating constrains the time for initiation of the Karakorum fault zone (KFZ), SW Tibet

    NASA Astrophysics Data System (ADS)

    Wang, Shifeng; Fang, Xiaomin; Lai, Qingzhou; Zheng, Dewen; Wang, Yanbin

    2009-10-01

    The Karakorum fault zone (KFZ), composed of strike-slip faults, has played an important role in intra-continental deformation during the Cenozoic convergence between the Indian and Eurasian plates. However, the spatial and temporal evolution of the KFZ remains under debate. This paper reports new zircon U-Pb Sensitive High Resolution Ion MicroProbe (SHRIMP) and biotite 40Ar/ 39Ar ages for samples from the fault zone to clarify the timing of events. The ages of Zircon U-Pb fall mainly around 47-50 Ma, which corresponds to a period of important magmatic activity of the Gangdese granitic belt (also known as the Trans-Himalayan magmatic belt). A metamorphic event followed in the period around 32 Ma, and that was then followed by a medium temperature cooling event between about 12 and 7.7 Ma. Biotite 40Ar/ 39Ar ages provide evidence that the 12-7.7 Ma cooling event coincides with the initiation of the KFZ cutting through the Ayilari granite. The Ayilari granite pluton does not seem to have experienced the separate 25-23 Ma cooling event, as shown in previous studies 60-80 km west of the current study area [Lacassin, R., Valli, F., Arnaud, N., Leloup, P.H., Paquette, J.L., Li, H., Tapponnier, P., Chevalier, M.L., Guillot, S., Maheo, G., Xu, Z., 2004. Large-scale geometry, offset and kinematic evolution of the Karakorum fault, Tibet. Earth and Planetary Science Letters 219 (3-4), 255-269.; Valli, F., Arnaud, N., Leloup, H.P., Sobel, E.R., Maheo, G., Lacassin, R., Guillot, S., Li, H., Tapponnier, P., Xu, Z., 2007. Twenty million years of continuous deformation along the Karakorum fault, western Tibet: a thermochronological analysis. Tectonics 26, doi: 10.1029/2005TC001913.; Valli, F., Leloup, P., Paquette, J., Arnaud, N., Li, H., Tapponnier, P., Lacassin, R., Guillot, S., Liu, D., Deloule, E., Xu, Z., Maho, G., 2008. New U-Th/Pb constraints on timing of shearing and long-term slip-rate on the Karakorum fault. Tectonics 27, doi:10.1029/2007TC002184.]. We conclude that the 25-23 Ma cooling event bears no relationship to the activity of the KFZ, but resulted from a local metamorphic event caused either by a regional tectonic event (such as activity of the south Kailas thrust fault) or by magmatism around Shiquanhe (also known as Gar). The study of the KFZ around Namru supports the opinion that the KFZ propagated along the fault strike to the Gar-Menshi area around 12 Ma.

  13. Data from radar images integrated with information from traditional lithologic and dating techniques improve resolution of surficial geologic units in the central Florida peninsula

    SciTech Connect

    McCartan, L.; Moy, W.S.; Wingard, G.L. Owens, J.P.; Kover, A.N.; Van Valkenburg, S.G.; Mason, D.B. )

    1994-03-01

    Side Looking Airborne Radar (SLAR) images provide information useful to 1:100,000-scale surficial geologic mapping across the Florida peninsula from Sarasota to Fort Pierce. The SLAR images show textural patterns, sharp gradients, and certain compositional variations that cause differences in reflectivity. Quaternary and Pliocene beach ridges and marginal marine plains, visible on SLAR images, occupy most of the eastern half of the area; the most prominent beach ridge, which was deposited during the late Pliocene or early Pleistocene, is the southern terminus of the central highlands of Florida. Other geologic features detected by radar are a change from iron-poor to moderately iron-rich soil that marks the boundary between two middle Quaternary ( ) units, oyster reefs associated with late Pleistocene bay deposits northwest of Lake Okeechobee, and permanent and ephemeral ponds that reflect the thickness of unconsolidated sediment over weathered carbonate rocks. In addition to the geomorphic and compositional information from SLAR, mineralogic, textural, and age data from drill holes and pits were used to delineate surficial geologic map units. Stratigraphic and numerical age estimates are based on molluscan biostratigraphy, uranium disequilibrium series dates on corals, [sup 87]Sr/[sup 66]Sr dates on molluscs, and [sup 14]C dates on peat and humate.

  14. In-flight Absolute Radiometric Calibration of the Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, D.; Savage, R. K.

    1984-01-01

    The Thematic Mapper (TM) multispectral scanner system was placed into Earth orbit on July 16, 1982, as part of NASA's LANDSAT 4 payload. To determine temporal changes of the absolute radiometric calibration of the entire system in flight, spectroradiometric measurements of the ground and the atmosphere are made simultaneously with TM image acquisitions over the White Sands, New Mexico area. By entering the measured values into an atmospheric radiative transfer program, the radiance levels at the entrance pupil of the TM in four of the TM spectral bands are determined. These levels are compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors. By reference to an adjacent, larger uniform area, the calibration is extended to all 16 detectors in each of the three bands.

  15. In-flight absolute radiometric calibration of the Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

    1984-01-01

    In order to determine temporal changes of the absolute radiometric calibration of the entire TM system in flight spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM image collections over the White Sands, NM area. By entering the measured values in an atmospheric radiative transfer program, the radiance levels in four of the spectral bands of the TM were determined, band 1: 0.45 to 0.52 micrometers, band 2: 0.53 to 0.61 micrometers, band 3: 0.62 to 0.70 micrometers, and 4: 0.78 to 0.91 micrometers. These levels were compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors. Previously announced in STAR as N84-15633

  16. In-flight absolute radiometric calibration of the thematic mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

    1984-01-01

    In order to determine temporal changes of the absolute radiometric calibration of the entire TM system in flight spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM image collections over the White Sands, New Mexico area. By entering the measured values in an atmospheric radiative transfer program, the radiance levels in four of the spectral bands of the TM were determined, band 1:0.45 to 0.52 micrometers, band 2:0.53 to 0.61 micrometers band 3:0.62 to 0.70 micrometers and 4:0.78 to 0.91 micrometers. These levels were compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors.

  17. Urease testing of mycobacteria with BACTEC radiometric instrumentation

    SciTech Connect

    Damato, J.J.; Collins, M.T.; McClatchy, J.K.

    1982-03-01

    A total of 140 mycobacterial isolates from patients treated at Fitzsimons Army Medical Center or the National Jewish Hospital and Research Center and from animal specimens submitted to the National Veterinary Services Laboratory were tested by using a urease procedure modified for use with a BACTEC model 301. Mycobacterial suspensions were prepared by using Middlebrook 7H10 Tween broth. Of the 98 mycobacteria isolates which were urease positive utilizing standard methodology, all were positive using the radiometric procedures. Similarly, all 42 urease-negative isolates were also negative employing the new methodology. Although maximum radiometric readings were observed at 48 h, all positive strains were readily identified 24 h after inoculation without sacrificing either test sensitivity or specificity. Thus, urease testing of mycobacteria, using the modified BACTEC radiometric methodology, was as sensitive, as specific, and more rapid than conventional methods.

  18. A Detailed Radiometric Chronological Framework for Nordic Seas Ocean-Ice Sheet Interactions Spanning 50-150 Ka BP

    NASA Astrophysics Data System (ADS)

    Brendryen, J.; Edwards, R. L.; Haflidason, H.; Cheng, H.; Grasmo, K. J.; Sejrup, H. P.

    2014-12-01

    Chronological control of sedimentary deposits is a key to do paleoclimatic interpretations of proxy records and to compare them with records from other archives. Beyond the reach of radiocarbon dating there are however few options for developing chronological control. We present a detailed radiometrical-based chronological framework of a Norwegian Sea core archive that records ocean-ice sheet interactions in the Nordic Seas covering the time span 50-150 ka BP. The chronology is based on a detailed multi-proxy and multi-archive alignment of high resolution records from the Norwegian Sea and precisely radiometric dated speleothem ?18O record from both China and the Alps. This approach utilizes the close and well documented millennial and multi-centennial scale coupling between the North Atlantic climate variability (recorded in the Norwegian Sea records, the Greenland ice cores and in the Alpine speleothems) and the Asian Monsoon system recorded in the Chinese speleothem ?18O. One intriguing feature of the Norwegian Sea record is that it often is more similar to the Chinese speleothem records than to the Greenland ice core records. The alignment is aided by a tephrostratigraphic link to the Greenland ice cores which provide an independent test of the age model and alignment. Uncertainties are addressed by Bayesian age-depth modeling. The radiometric-based age model and the quantified uncertainties enable an independent comparison between the Nordic Seas ocean-ice sheet interaction and other absolutely dated records such as U/Th dated sea-level indices and orbital parameters. This improves our ability to interpret the ocean-ice sheet interactions of the polar north in a global context over this time span that comprises a glacial-interglacial cycle.

  19. Radiometric Calibration of the Earth Observing System's Imaging Sensors

    NASA Technical Reports Server (NTRS)

    Slater, Philip N. (Principal Investigator)

    1997-01-01

    The work on the grant was mainly directed towards developing new, accurate, redundant methods for the in-flight, absolute radiometric calibration of satellite multispectral imaging systems and refining the accuracy of methods already in use. Initially the work was in preparation for the calibration of MODIS and HIRIS (before the development of that sensor was canceled), with the realization it would be applicable to most imaging multi- or hyper-spectral sensors provided their spatial or spectral resolutions were not too coarse. The work on the grant involved three different ground-based, in-flight calibration methods reflectance-based radiance-based and diffuse-to-global irradiance ratio used with the reflectance-based method. This continuing research had the dual advantage of: (1) developing several independent methods to create the redundancy that is essential for the identification and hopefully the elimination of systematic errors; and (2) refining the measurement techniques and algorithms that can be used not only for improving calibration accuracy but also for the reverse process of retrieving ground reflectances from calibrated remote-sensing data. The grant also provided the support necessary for us to embark on other projects such as the ratioing radiometer approach to on-board calibration (this has been further developed by SBRS as the 'solar diffuser stability monitor' and is incorporated into the most important on-board calibration system for MODIS)- another example of the work, which was a spin-off from the grant funding, was a study of solar diffuser materials. Journal citations, titles and abstracts of publications authored by faculty, staff, and students are also attached.

  20. Ellipsoidal geometry in asteroid thermal models - The standard radiometric model

    NASA Technical Reports Server (NTRS)

    Brown, R. H.

    1985-01-01

    The major consequences of ellipsoidal geometry in an othewise standard radiometric model for asteroids are explored. It is shown that for small deviations from spherical shape a spherical model of the same projected area gives a reasonable aproximation to the thermal flux from an ellipsoidal body. It is suggested that large departures from spherical shape require that some correction be made for geometry. Systematic differences in the radii of asteroids derived radiometrically at 10 and 20 microns may result partly from nonspherical geometry. It is also suggested that extrapolations of the rotational variation of thermal flux from a nonspherical body based solely on the change in cross-sectional area are in error.

  1. Research radiometric calibration quantitative transfer methods between internal and external

    NASA Astrophysics Data System (ADS)

    Guo, Ju Guang; Ma, Yong hui; Zhang, Guang; Yang, Zhi hui

    2015-10-01

    This paper puts forward a method by realizing the internal and external radiation calibration transfer for infrared radiation characteristics quantitative measuring system. Through technological innovation and innovation application to establish a theoretical model of the corresponding radiated transfer method. This method can be well in engineering application for technology conversion process of radiometric calibration that with relatively simple and effective calibration in the half light path radiation instead of complex difficult whole optical path radiometric calibration. At the same time, it also will provide the basis of effective support to further carry out the target radiated characteristics quantitative measurement and application for ground type infrared radiated quantitative measuring system.

  2. Simulations of three-dimensional radiometric imaging of extended sources in a security screening portal

    NASA Astrophysics Data System (ADS)

    Salmon, Neil A.; Bowring, Nick

    2015-10-01

    This paper investigates by simulation the use of the three-dimensional aperture synthesis imaging technique to image three-dimensional extended sources. Software was written to access the three-dimensional information from computer graphics models in the formats of *.dxf and *.3ds and use these to generate synthetic cross-correlations, as if they would have been generated by an aperture synthesis antenna/receiver array measuring the radiometric emission from the three-dimensional object. A three-dimensional (near-field) aperture synthesis imaging algorithm generates [1] a voxel image of the three-dimensional object. Images created from a sphere indicate faithful reproduction about a single phase centre when the radius of the sphere is less than the Fresnel scale. However, for larger spheres, definition in the threedimensional imagery suffers and a phenomenon, referred to in this paper as Fresnel noise, appears in the image. Images of objects larger than the Fresnel scale can be created by having multiple smaller images, each having a size approximately of the Fresnel scale and centred on separate phase centres. Using the software to generate threedimensional imagery of a person, to demonstrate capabilities for portal security screening, indicates the technique works to first order. Improvements are needed in the software to improve the spatial sampling of the radiometric fields from the three-dimensional objects and implement a volumetric image mosaicking technique to remove the Fresnel noise.

  3. Radiometric Measurement Comparisons Using Transfer Radiometers in Support of the Calibration of NASA's Earth Observing System (EOS) Sensors

    NASA Technical Reports Server (NTRS)

    Butler, James J.; Johnson, B. Carol; Brown, Steven W.; Yoon, Howard W.; Barnes, Robert A.; Markham, Brian L.; Biggar, Stuart F.; Zalewski, Edward F.; Spyak, Paul R.; Cooper, John W.; Sakuma, Fumihiro

    1999-01-01

    EOS satellite instruments operating in the visible through the shortwave infrared wavelength regions (from 0.4 micrometers to 2.5 micrometers) are calibrated prior to flight for radiance response using integrating spheres at a number of instrument builder facilities. The traceability of the radiance produced by these spheres with respect to international standards is the responsibility of the instrument builder, and different calibration techniques are employed by those builders. The National Aeronautics and Space Administration's (NASA's) Earth Observing System (EOS) Project Science Office, realizing the importance of preflight calibration and cross-calibration, has sponsored a number of radiometric measurement comparisons, the main purpose of which is to validate the radiometric scale assigned to the integrating spheres by the instrument builders. This paper describes the radiometric measurement comparisons, the use of stable transfer radiometers to perform the measurements, and the measurement approaches and protocols used to validate integrating sphere radiances. Stable transfer radiometers from the National Institute of Standards and Technology, the University of Arizona Optical Sciences Center Remote Sensing Group, NASA's Goddard Space Flight Center, and the National Research Laboratory of Metrology in Japan, have participated in these comparisons. The approaches used in the comparisons include the measurement of multiple integrating sphere lamp levels, repeat measurements of select lamp levels, the use of the stable radiometers as external sphere monitors, and the rapid reporting of measurement results. Results from several comparisons are presented. The absolute radiometric calibration standard uncertainties required by the EOS satellite instruments are typically in the +/- 3% to +/- 5% range. Preliminary results reported during eleven radiometric measurement comparisons held between February 1995 and May 1998 have shown the radiance of integrating spheres agreed to within +/- 2.5% from the average at blue wavelengths and to within +/- 1.7% from the average at red and near infrared wavelengths. This level of agreement lends confidence in the use of the transfer radiometers in validating the radiance scales assigned by EOS instrument calibration facilities to their integrating sphere sources.

  4. ASD FieldSpec Calibration Setup and Techniques

    NASA Technical Reports Server (NTRS)

    Olive, Dan

    2001-01-01

    This paper describes the Analytical Spectral Devices (ASD) Fieldspec Calibration Setup and Techniques. The topics include: 1) ASD Fieldspec FR Spectroradiometer; 2) Components of Calibration; 3) Equipment list; 4) Spectral Setup; 5) Spectral Calibration; 6) Radiometric and Linearity Setup; 7) Radiometric setup; 8) Datadets Required; 9) Data files; and 10) Field of View Measurement. This paper is in viewgraph form.

  5. A preliminary study of a very large space radiometric antenna

    NASA Technical Reports Server (NTRS)

    Agrawal, P. K.

    1979-01-01

    An approach used to compute the size of a special radiometric reflector antenna is presented. Operating at 1 GHz, this reflector is required to produce 200 simultaneous contiguous beams, each with a 3 dB footprint of 1 km from an assumed satellite height of 650 km. The overall beam efficiency for each beam is required to be more than 90%.

  6. Laboratory-based bidirectional reflectance distribution functions of radiometric tarps

    SciTech Connect

    Georgiev, Georgi T.; Butler, James J

    2008-06-20

    Laboratory-based bidirectional reflectance distribution functions (BRDFs) of radiometric tarp samples used in the vicarious calibration of Earth remote sensing satellite instruments are presented in this paper. The results illustrate the BRDF dependence on the orientation of the tarps' weft and warp threads. The study was performed using the GSFC scatterometer at incident zenith angles of 0 deg., 10 deg., and 30 deg.; scatter zenith angles from 0 deg. to 60 deg.; and scatter azimuth angles of 0 deg., 45 deg., 90 deg., 135 deg., and 180 deg.. The wavelengths were 485 nm, 550 nm, 633 nm, and 800 nm. The tarp's weft and warp dependence on BRDF is well defined at all measurement geometries and wavelengths. The BRDF difference can be as high as 8% at 0 deg. incident angle and 12% at 30 deg. incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps are reported. The backward scatter is well pronounced for the white samples. The black sample has well-pronounced forward scatter. The provided BRDF characterization of radiometric tarps is an excellent reference for anyone interested in using tarps for radiometric calibrations. The results are NIST traceable.

  7. Laboratory-based bidirectional reflectance distribution functions of radiometric tarps.

    PubMed

    Georgiev, Georgi T; Butler, James J

    2008-06-20

    Laboratory-based bidirectional reflectance distribution functions (BRDFs) of radiometric tarp samples used in the vicarious calibration of Earth remote sensing satellite instruments are presented in this paper. The results illustrate the BRDF dependence on the orientation of the tarps' weft and warp threads. The study was performed using the GSFC scatterometer at incident zenith angles of 0 degrees, 10 degrees, and 30 degrees; scatter zenith angles from 0 degrees to 60 degrees; and scatter azimuth angles of 0 degrees, 45 degrees, 90 degrees, 135 degrees, and 180 degrees. The wavelengths were 485 nm, 550 nm, 633 nm, and 800 nm. The tarp's weft and warp dependence on BRDF is well defined at all measurement geometries and wavelengths. The BRDF difference can be as high as 8% at 0 degrees incident angle and 12% at 30 degrees incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps are reported. The backward scatter is well pronounced for the white samples. The black sample has well-pronounced forward scatter. The provided BRDF characterization of radiometric tarps is an excellent reference for anyone interested in using tarps for radiometric calibrations. The results are NIST traceable. PMID:18566627

  8. Radiometric observation of the atmospheric boundary layer (the ROSSA Project)

    NASA Astrophysics Data System (ADS)

    Hepplewhite, C. L.

    1989-12-01

    Radiometric measurements of the ocean skin temperature together with bulk water temperatures, simultaneous radiosonde ascents, and satellite infrared radiances are used to investigate the oceanic skin effect, the sea surface emissivity, and the atmospheric transmission of infrared radiation, in the window region of 8 to 12 microns. A radiometer sensitive to infrared radiation in the spectral range 6.5 to 14 microns, was designed, built, and used to obtain sea surface skin temperatures to an accuracy of between 0.20 K and 0.25 K with a resolution of between 0.03 K and 0.05 K. Satellite radiances were provided by the advanced very high resolution radiometer (AVHRR)/2 instrument on NOAA-9, and atmospheric temperature and humidity profiles from Vaisala radiosondes launched from the ship. Investigations of the oceanic skin effect were made by comparing the measurements of skin sea surface temperature obtained using the radiometer with bulk temperatures. In terms of the overall average of the complete Atlantic Ocean data set, the skin of the sea was found to be 0.30 K cooler than the bulk, about 10 cm below the surface. The variability of the skin effect was found to be smaller in the tropics and greater at higher latitudes. The sea surface emissivity was found to vary very little with sea state at viewing angles less than about 45 deg. However, at these viewing angles and under calm, clear conditions, the surface brightness temperature was observed to fall when viewed at the vertical. Studies of the transmission of radiation in the atmospheric window region show that the effect on the atmospheric temperature deficit of different water vapor continuum models can not be distinguished from the effects of aerosols. When there are aerosols present, the retrieval of the sea surface temperature (SST) from space using the split window algorithms is subject to large errors. The dual angle technique is shown to be capable of retrieving SST to a higher degree of accuracy than the multi-channel technique, particularly in the presence of aerosol.

  9. Changes in the Radiometric sensitivity of SeaWiFS determined from lunar and solar-based measurements.

    PubMed

    Barnes, R A; Eplee, R E; Patt, F S; McClain, C R

    1999-07-20

    We report on the lunar and solar measurements used to determine the changes in the radiometric sensitivity of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Radiometric sensitivity is defined as the output from the instrument (or from one of the instrument bands) per unit spectral radiance at the instrument's input aperture. Knowledge of the long-term repeatability of the SeaWiFS measurements is crucial to maintaining the quality of the ocean scenes derived from measurements by the instrument. For SeaWiFS bands 1-6 (412-670 nm), the change in radiometric sensitivity is less than 0.2% for the period from November 1997 through November 1998. For band 7 (765 nm), the change is approximately 1.5% and for band 8 (865 nm) approximately 5%. The rates of change of bands 7 and 8, which were linear with time for the first eight months of lunar measurements, are now slowing. The scatter in the data points about the trend lines in this analysis is less than 0.3% for all eight SeaWiFS bands. These results are based on monthly measurements of the moon. Daily solar measurements using an onboard diffuser show that the radiometric sensitivities of the SeaWiFS bands have changed smoothly during the time intervals between lunar measurements. Because SeaWiFS measurements have continued past November 1998, the results presented here are considered as a snapshot of the instrument performance as of that date. PMID:18323952

  10. QuEChERS, a sample preparation technique that is catching on: an up-to-date interview with its inventors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technique of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) is only 7 years old, yet it is revolutionizing the manner in which multiresidue, multiclass pesticide analysis (and perhaps beyond) is performed. Columnist Ron Majors sits down with inventors Steve Lehotay and Michelangelo An...

  11. Mississippi Valley-type lead-zinc deposits through geological time: Implications from recent age-dating research

    USGS Publications Warehouse

    Leach, D.L.; Bradley, D.; Lewchuk, Michael T.; Symons, David T. A.; De Marsily, G.; Brannon, J.

    2001-01-01

    Remarkable advances in age dating Mississippi Valley-type (MVT) lead-zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead-zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary time when microplate assimilation affected the western margin of North America and Africa-Eurasia. There is a notable paucity of MVT lead-zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead-zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian time. The exceptional endowment of Pangea and especially, North America with MVT lead-zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.

  12. Mississippi Valley-type lead-zinc deposits through geological time: implications from recent age-dating research

    NASA Astrophysics Data System (ADS)

    Leach, David L.; Bradley, Dwight; Lewchuk, Michael T.; Symons, David T.; de Marsily, Ghislain; Brannon, Joyce

    2001-12-01

    Remarkable advances in age dating Mississippi Valley-type (MVT) lead-zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead-zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary time when microplate assimilation affected the western margin of North America and Africa-Eurasia. There is a notable paucity of MVT lead-zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead-zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian time. The exceptional endowment of Pangea and especially, North America with MVT lead-zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.

  13. Calibration of cosmogenic noble gas production based on 36Cl-36Ar ages. Part 2. The 81Kr-Kr dating technique

    NASA Astrophysics Data System (ADS)

    Leya, I.; Dalcher, N.; Vogel, N.; Wieler, R.; Caffee, M. W.; Welten, K. C.; Nishiizumi, K.

    2015-11-01

    We calibrated the 81Kr-Kr dating system for ordinary chondrites of different sizes using independent shielding-corrected 36Cl-36Ar ages. Krypton concentrations and isotopic compositions were measured in bulk samples from 14 ordinary chondrites of high petrologic type and the cosmogenic Kr component was obtained by subtracting trapped Kr from phase Q. The thus-determined average cosmogenic 78Kr/83Kr, 80Kr/83Kr, 82Kr/83Kr, and 84Kr/83Kr ratiC(Lavielle and Marti 1988; Wieler 2002). The cosmogenic 78Kr/83Kr ratio is correlated with the cosmogenic 22Ne/21Ne ratio, confirming that 78Kr/83Kr is a reliable shielding indicator. Previously, 81Kr-Kr ages have been determined by assuming the cosmogenic production rate of 81Kr, P(81Kr)c, to be 0.95 times the average of the cosmogenic production rates of 80Kr and 82Kr; the factor Y = 0.95 therefore accounts for the unequal production of the various Kr isotopes (Marti 1967a). However, Y should be regarded as an empirical adjustment. For samples whose 80Kr and 82Kr concentrations may be affected by neutron-capture reactions, the shielding-dependent cosmogenic (78Kr/83Kr)c ratio has been used instead to calculate P(81Kr)/P(83Kr), as for some lunar samples, this ratio has been shown to linearly increase with (78Kr/83Kr)c (Marti and Lugmair 1971). However, the 81Kr-Kr ages of our samples calculated with these methods are on average ~30% higher than their 36Cl-36Ar ages, indicating that most if not all the 81Kr-Kr ages determined so far are significantly too high. We therefore re-evaluated both methods to determine P(81Kr)c/P(83Kr)c. Our new Y value of 0.70 ± 0.04 is more than 25% lower than the value of 0.95 used so far. Furthermore, together with literature data, our data indicate that for chondrites, P(81Kr)c/P(83Kr)c is rather constant at 0.43 ± 0.02, at least for the shielding range covered by our samples ([78Kr/83Kr]c = 0.119-0.185; [22Ne/21Ne]c = 1.083-1.144), in contrast to the observations on lunar samples. As expected considering the method used, 81Kr-Kr ages calculated either directly with this new P(81Kr)c/P(83Kr)c value or with our new Y value both agree with the corresponding 36Cl-36Ar ages. However, the average deviation of 2% indicates the accuracy of both new 81Kr-Kr dating methods and the precision of the new dating systems of ~10% is demonstrated by the low scatter in the data. Consequently, this study indicates that the 81Kr-Kr ages published so far are up to 30% too high.

  14. Early Acheulean technology in the Rietputs Formation, South Africa, dated with cosmogenic nuclides.

    PubMed

    Gibbon, Ryan J; Granger, Darryl E; Kuman, Kathleen; Partridge, Timothy C

    2009-02-01

    An absolute dating technique based on the build-up and decay of (26)Al and (10)Be in the mineral quartz provides crucial evidence regarding early Acheulean hominid distribution in South Africa. Cosmogenic nuclide burial dating of an ancient alluvial deposit of the Vaal River (Rietputs Formation) in the western interior of South Africa shows that coarse gravel and sand aggradation there occurred ca 1.57+/-0.22Ma, with individual ages of samples ranging from 1.89+/-0.19 to 1.34+/-0.22Ma. This was followed by aggradation of laminated and cross-bedded fine alluvium at ca 1.26+/-0.10Ma. The Rietputs Formation provides an ideal situation for the use of the cosmogenic nuclide burial dating method, as samples could be obtained from deep mining pits at depths ranging from 7 to 16 meters. Individual dates provide only a minimum age for the stone tool technology preserved within the deposits. Each assemblage represents a time averaged collection. Bifacial tools distributed throughout the coarse gravel and sand unit can be assigned to an early phase of the Acheulean. This is the first absolute radiometric dated evidence for early Acheulean artefacts in South Africa that have been found outside of the early hominid sites of the Gauteng Province. These absolute dates also indicate that handaxe-using hominids inhabited southern Africa as early as their counterparts in East Africa. The simultaneous appearance of the Acheulean in different parts of the continent implies relatively rapid technology development and the widespread use of large cutting tools in the African continent by ca 1.6Ma. PMID:19101709

  15. Recognition of past earthquakes along the Sparta fault (Peloponnesus, southern Greece) during the Holocene, by combining results of different dating techniques

    NASA Astrophysics Data System (ADS)

    Papanastassiou, D.; Gaki-Papanastassiou, K.; Maroukian, H.

    2005-09-01

    Sparta fault is an impressive landform, located on the eastern front of Taygetos mountain, southern Greece. Detailed morphotectonic observations on this fault suggest that it should be active at least since Early Quaternary. However, according to the current seismological knowledge, this region is characterized by very low seismicity. The only reported earthquake to have occurred in this area is that of 464 B. C., a destructive event that devastated the whole city of Sparta. In order to get information on the occurrence of past earthquakes during the Holocene, results of different independent dating works that have performed along the Sparta fault were used. These researchers confirm the existence not only of the 464 B. C. earthquake but also of several more that occurred at ca. 3900 B. C., 2500 B. C. and 2000 B. C., 550 A. D. and 1000 A. D. The events that occurred at 2500 and 464 B. C. should correspond to major events of magnitude of the order of 7, which ruptured the entire length of the fault, while these at 3900 B. C., 2000 B. C., 550 A. D. and 1000 A. D., to smaller events of magnitude 6-6.5. The return periods of strong earthquakes along the Sparta fault is estimated to be around 2000 years, but within these periods events of smaller magnitude that ruptured segments of the fault have also occurred.

  16. Radiometric Calibration of Earth-Observing Sensors Using the Radiometric Calibration Test Site (RadCaTS)

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, J.; Anderson, N. J.; Thome, K. J.; Biggar, S. F.

    2014-12-01

    The Remote Sensing Group (RSG) of the College of Optical Sciences at the University of Arizona uses the reflectance-based approach to perform the absolute radiometric calibration of such sensors as Landsat 5 TM, Landsat 7 ETM+, Landsat 8 OLI, Terra and Aqua MODIS, ASTER, RapidEye, and others. The reflectance-based approach requires that personnel be present at a test site during the sensor overpass, so the Radiometric Calibration Test Site (RadCaTS) was developed in order to capture data during every possible overpass, which assists in the temporal trending of the radiometric calibration of earth-observing sensors. The number of earth-observing sensors is rapidly increasing in recent years, and RadCaTS provides the ability to radiometrically calibrate them without the requirement of frequent field campaigns. The 2013 launch of Landsat 8 provides a unique opportunity for RadCaTS in that it is being used to supplement the in situ measurements by RSG ground personnel, and it will be used throughout the lifetime of the Landsat 8 mission. This allows more data to be collected throughout the year, and it also allows the accuracy and uncertainty of RadCaTS to be analyzed. The current top-of-atmosphere (TOA) spectral radiance uncertainty of the reflectance-based approach is ~2.6% in the mid-visible region of the spectrum, and current work indicates that the uncertainty of RadCaTS in TOA spectral radiance is ~3-4%. This work presents the radiometric calibration results of RadCaTS for a variety of sensors such as Landsat 7 ETM+, Landsat 8 OLI, Terra and Aqua MODIS, MISR, ASTER, and Suomi NPP VIIRS.

  17. Radiometric and spectral calibrations of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) using principle component analysis

    NASA Astrophysics Data System (ADS)

    Tian, Jialin; Smith, William L.; Gazarik, Michael J.

    2008-10-01

    The ultimate remote sensing benefits of the high resolution Infrared radiance spectrometers will be realized with their geostationary satellite implementation in the form of imaging spectrometers. This will enable dynamic features of the atmosphere's thermodynamic fields and pollutant and greenhouse gas constituents to be observed for revolutionary improvements in weather forecasts and more accurate air quality and climate predictions. As an important step toward realizing this application objective, the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstration Unit (EDU) was successfully developed under the NASA New Millennium Program, 2000-2006. The GIFTS-EDU instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw GIFTS interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. The radiometric calibration is achieved using internal blackbody calibration references at ambient (260 K) and hot (286 K) temperatures. The absolute radiometric performance of the instrument is affected by several factors including the FPA off-axis effect, detector/readout electronics induced nonlinearity distortions, and fore-optics offsets. The GIFTS-EDU, being the very first imaging spectrometer to use ultra-high speed electronics to readout its large area format focal plane array detectors, operating at wavelengths as large as 15 microns, possessed non-linearity's not easily removable in the initial calibration process. In this paper, we introduce a refined calibration technique that utilizes Principle Component (PC) analysis to compensate for instrument distortions and artifacts remaining after the initial radiometric calibration process, thus, further enhance the absolute calibration accuracy. This method is applied to data collected during an atmospheric measurement experiment with the GIFTS, together with simultaneous observations by the accurately calibrated AERI (Atmospheric Emitted Radiance Interferometer), both simultaneously zenith viewing the sky through the same external scene mirror at ten-minute intervals throughout a cloudless day at Logan Utah on September 13, 2006. The PC vectors of the calibrated radiance spectra are defined from the AERI observations and regression matrices relating the initial GIFTS radiance PC scores to the AERI radiance PC scores are calculated using the least squares inverse method. A new set of accurately calibrated GIFTS radiances are produced using the first four PC scores in the regression model. Temperature and moisture profiles retrieved from the PC-calibrated GIFTS radiances are verified against radiosonde measurements collected throughout the GIFTS sky measurement period.

  18. Application and sensitivity investigation of Fourier transforms for microwave radiometric inversions

    NASA Technical Reports Server (NTRS)

    Holmes, J. J.; Balanis, C. A.

    1974-01-01

    Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature equation, an unstable Fredholm integral equation of the first kind was solved. Fast Fourier Transform techniques were used to invert the integral after it is placed into a cross-correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system were included. The instability of the Fredholm equation was then demonstrated and a restoration procedure was included which smooths the resulting oscillations. With the recent availability and advances of Fast Fourier Transform techniques, the method presented becomes very attractive in the evaluation of large quantities of data. Actual radiometric measurements of sea water are inverted using the restoration method, incorporating the advantages of the Fast Fourier Transform algorithm for computations.

  19. Electronic transport characterization of silicon wafers by spatially resolved steady-state photocarrier radiometric imaging

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Li, Bincheng

    2015-09-01

    Spatially resolved steady-state photocarrier radiometric (PCR) imaging technique is developed to characterize the electronic transport properties of silicon wafers. Based on a nonlinear PCR theory, simulations are performed to investigate the effects of electronic transport parameters (the carrier lifetime, the carrier diffusion coefficient, and the front surface recombination velocity) on the steady-state PCR intensity profiles. The electronic transport parameters of an n-type silicon wafer are simultaneously determined by fitting the measured steady-state PCR intensity profiles to the three-dimensional nonlinear PCR model. The determined transport parameters are in good agreement with the results obtained by the conventional modulated PCR technique with multiple pump beam radii.

  20. Radiometrically calibrated scene-based nonuniformity correction for infrared array sensors

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Hayat, Majeed M.; Tyo, J. Scott

    2003-01-01

    This paper describes how a limited form of black-body-based calibration can be integrated into a recently developed algebraic scene-based algorithm for nonuniformity correction (NUC) in focal-plane arrays. The result of this integration is a scene-based NUC algorithm that is radiometrically accurate. By calibrating only those detectors that are on the array perimeter and relying on the scene-based algorithm to calibrate the interior detectors, using the perimeter detectors as a reference, radiometric accuracy can be achieved without disturbing the functionality of interior array elements. What makes this possible is the fact that the scene-based NUC algorithm used here is algebraic in nature and does not rely on any statistical assumptions on the scene irradiance in the image sequence. The algorithm utilizes knowledge of inter-frame motion to 'lock' the biases of the interior array elements to those on the boundary. Notably, this can be achieved regardless of the spatial diversity in the scene and with, typically, a minimal number of frames in an image sequence. The performance of the technique is demonstrated using real infrared data.

  1. Radiometric method for testing susceptibility of mycobacteria to pyrazinamide in 7H12 broth

    SciTech Connect

    Heifets, L.B.; Iseman, M.D.

    1985-02-01

    The test of susceptibility to pyrazinamide requires an acid environment (pH less than or equal to 5.5). This, however, is not favorable to the growth of Mycobacterium tuberculosis, especially in solid agar media. To obviate this difficulty, we developed a testing method with 7H12 broth medium and based on radiometric readings of the growth. The radiometric method employed in this study (BACTEC system) provides an opportunity to detect the dynamics of growth by daily recording of the growth index, which reflects the metabolic activity of the multiplying bacteria. In our technique, M. tuberculosis isolates were initially cultivated at pH 6.8. After logarithmic growth had begun, phosphoric acid solution was added to obtain pH 5.5. When pyrazinamide was added simultaneously with the acid, the growth index of susceptible cultures decreased, whereas it continued to increase in pH 5.5 control vials and in tests with pyrazinamide-resistant strains.

  2. Rapid radiometric method for detection of Salmonella in foods

    SciTech Connect

    Stewart, B.J.; Eyles, M.J.; Murrell, W.G.

    1980-08-01

    A radiometric method for the detection of Salmonella in foods has been developed which is based on Salmonella poly H agglutinating serum preventing Salmonella from producing 14CO2 from (14C) dulcitol. The method will detect the presence or absence of Salmonella in a product within 30 h compared to 4 to 5 days by routine culture methods. The method has been evaluated against a routine culture method using 58 samples of food. The overall agreement was 91%. Five samples negative for Salmonella by the routine method were positive by the radiometric method. These may have been false positives. However, the routine method may have failed to detect Salmonella due to the presence of large numbers of lactose-fermenting bacteria which hindered isolation of Salmonella colonies on the selective agar plates.

  3. UV/VUV radiometric calibrations at SURF II

    NASA Technical Reports Server (NTRS)

    Furst, Mitchell L.; Canfield, L. R.

    1993-01-01

    Since 1981 more than 150 instrument calibrations have been performed on the radiometric instrumentation calibration beamline at the Synchrotron Ultraviolet Radiation Facility (SURF II) at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. This 300 MeV electron storage ring operates routinely at electron currents greater than 250 mA. The spectrometer calibration beamline provides a continuum of radiation from 4 nm through the visual spectral region in the form of an intense beam with total angular divergence of 1.2 mrad. The probable uncertainty for the flux ranges from about 5 percent at 4 nm to less than 2 percent above 20 nm. The new system will radiometrically trace to SURF II, and thus is expected to reduce the calibration uncertainty for diodes in this region by a factor of five to the 1-2 percent level.

  4. Development and calibration of UV/VUV radiometric sources

    NASA Technical Reports Server (NTRS)

    Bridges, J. M.

    1993-01-01

    A program exists at NIST to calibrate radiometric sources for the spectral range from 118-350 nm. These include deuterium lamps, hollow-cathode lamps, RF-excited dimer lamps, and wall-stabilized argon arcs. Sources have been calibrated for and used by researchers in solar physics, astrophysics, atmospheric physics (ozone measurements), magnetically controlled fusion, and photobiology. The argon arcs were developed in our laboratory, and provide intense sources of both radiance and irradiance. Calibrations are performed relative to two primary sources, a wall-stabilized hydrogen arc and a 12,000 K black-body line arc, both developed in our laboratory. Also we recently have begun periodic calibrations on the NIST storage ring, SURF II, to insure consistency between our respective radiometric bases. Various sources have been calibrated for space' applications, including several which are flyable. Also, some development and testing of radiometers for semiconductor lithography were recently carried out with an intense argon arc source.

  5. The OLI Radiometric Scale Realization Round Robin Measurement Campaign

    NASA Technical Reports Server (NTRS)

    Cutlip, Hansford; Cole,Jerold; Johnson, B. Carol; Maxwell, Stephen; Markham, Brian; Ong, Lawrence; Hom, Milton; Biggar, Stuart

    2011-01-01

    A round robin radiometric scale realization was performed at the Ball Aerospace Radiometric Calibration Laboratory in January/February 2011 in support of the Operational Land Imager (OLI) Program. Participants included Ball Aerospace, NIST, NASA Goddard Space Flight Center, and the University of Arizona. The eight day campaign included multiple observations of three integrating sphere sources by nine radiometers. The objective of the campaign was to validate the radiance calibration uncertainty ascribed to the integrating sphere used to calibrate the OLI instrument. The instrument level calibration source uncertainty was validated by quatnifying: (1) the long term stability of the NIST calibrated radiance artifact, (2) the responsivity scale of the Ball Aerospace transfer radiometer and (3) the operational characteristics of the large integrating sphere.

  6. The 90 GHz radiometric imaging. [for terrain analysis

    NASA Technical Reports Server (NTRS)

    King, H. E.; White, J. D.; Wilson, W. J.; Mori, T. T.; Hollinger, J. P.; Troy, B. E.; Kenney, J. E.; Mcgoogan, J. T.

    1976-01-01

    A 90-GHz (3 mm wavelength) radiometer with a noise output fluctuation of 0.22 K (RMS), with a scanning antenna beam mirror, and the data processing system are described. Real-time radiometric imaging of terrain and man-made objects are shown. Flying at an altitude of 1500 ft a radiometer antenna with a 2 degrees halfpower beamwidth can distinguish landforms, waterways, roads, runways, bridges, ships at sea and their wakes, aircraft on runways, and athletic fields. A flight taken at an altitude of 3000 ft with approximately 2000 ft of clouds below the radiometer demonstrates the ability to distinguish bridges, rivers, marshland and other landforms even though the clouds are optically opaque. The radiometric images of a few representative scenes along with photographs of the corresponding scenes are presented to demonstrate the resolution of the imager system.

  7. High speed radiometric measurements of IED detonation fireballs

    NASA Astrophysics Data System (ADS)

    Spidell, Matthew T.; Gordon, J. Motos; Pitz, Jeremey; Gross, Kevin C.; Perram, Glen P.

    2010-04-01

    Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step in moving from "laboratory" measurements to a rugged, fieldable system. To explore phenomena not observable in previous experiments, a high speed (10μs resolution) radiometer with four channels spanning the infrared spectrum observed the detonation of nine home made explosive (HME) devices in the < 100lb class. Radiometric measurements indicate that the detonation fireball is well approximated as a single temperature blackbody at early time (0 < t <~ 3ms). The effective radius obtained from absolute intensity indicates fireball growth at supersonic velocity during this time. Peak fireball temperatures during this initial detonation range between 3000.3500K. The initial temperature decay with time (t <~ 10ms) can be described by a simple phenomenological model based on radiative cooling. After this rapid decay, temperature exhibits a small, steady increase with time (10 <~ t <~ 50ms) and peaking somewhere between 1000.1500K-likely the result of post-detonation combustion-before subsequent cooling back to ambient conditions . Radius derived from radiometric measurements can be described well (R2 > 0.98) using blast model functional forms, suggesting that energy release could be estimated from single-pixel radiometric detectors. Comparison of radiometer-derived fireball size with FLIR infrared imagery indicate the Planckian intensity size estimates are about a factor of two smaller than the physical extent of the fireball.

  8. BOREAS TE-18, 60-m, Radiometrically Rectified Landsat TM Imagery

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David

    2000-01-01

    The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 2 1 Jun-1995. The 23 rectified images cover the period of 07-Jul-1985 to 18-Sep-1994 in the SSA and 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (1991). The original Landsat TM data were received from CCRS for use in the BOREAS project. Due to the nature of the radiometric rectification process and copyright issues, the full-resolution (30-m) images may not be publicly distributed. However, this spatially degraded 60-m resolution version of the images may be openly distributed and is available on the BOREAS CD-ROM series. After the radiometric rectification processing, the original data were degraded to a 60-m pixel size from the original 30-m pixel size by averaging the data over a 2- by 2-pixel window. The data are stored in binary image-format files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

  9. LANDSAT-4 multispectral scanner (MSS) subsystem radiometric characterization

    NASA Technical Reports Server (NTRS)

    Alford, W. (Editor); Barker, J. (Editor); Clark, B. P.; Dasgupta, R.

    1983-01-01

    The multispectral band scanner (mass) and its spectral characteristics are described and methods are given for relating video digital levels on computer compatible tapes to radiance into the sensor. Topics covered include prelaunch calibration procedures and postlaunch radiometric processng. Examples of current data resident on the MSS image processing system are included. The MSS on LANDSAT 4 is compared with the scanners on earlier LANDSAT satellites.

  10. Sentinel-2 radiometric image quality commissioning: first results

    NASA Astrophysics Data System (ADS)

    Lachérade, S.; Lonjou, V.; Farges, M.; Gamet, P.; Marcq, S.; Raynaud, J.-L.; Trémas, T.

    2015-10-01

    In partnership with the European Commission and in the frame of the Copernicus program, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. Sentinel-2 offers a unique combination of global coverage with a wide field of view (290km), a high revisit (5 days with two satellites), a high spatial resolution (10m, 20m and 60m) and multi-spectral imagery (13 spectral bands in visible and shortwave infrared domains). The first satellite, Sentinel-2A, has been launched in June 2015. The Sentinel-2A Commissioning Phase starts immediately after the Launch and Early Orbit Phase and continues until the In-Orbit Commissioning Review which is planned three months after the launch. The Centre National d'Etudes Spatiales (CNES) supports ESA/ESTEC to insure the Calibration/Validation commissioning phase during the first three months in flight. This paper provides first an overview of the Sentinel-2 system and a description of the products delivered by the ground segment associated to the main radiometric specifications to achieve. Then the paper focuses on the preliminary radiometric results obtained during the in-flight commissioning phase. The radiometric methods and calibration sites used in the CNES image quality center to reach the specifications of the sensor are described. A status of the Sentinel-2A radiometric performances at the end of the first three months after the launch is presented. We will particularly address in this paper the results in term of absolute calibration, pixel to pixel relative sensitivity and MTF estimation.

  11. Up-to-date Review and Cases Report on Chondral Defects of Knee Treated by ACI Technique: Clinical-instrumental and Histological Results.

    PubMed

    Dell'Osso, Giacomo; Ghilardi, Marco; Bottai, Vanna; Bugelli, Giulia; Guido, Giulio; Giannotti, Stefano

    2015-05-01

    The limited regenerative potential of a full thickness defect of the knee joint cartilage has certainly conditioned the development of therapeutic strategies that take into account all the aspects of the healing process. The most common treatments to repair chondral and osteochondral lesions are bone marrow stimulation, osteochondral autograft transplantation, autologous matrix-induced chondrogenesis, and autologous chondrocyte implantation. We like to emphasize the difference between a chondral and an osteochondral lesion because the difference is sometimes lost in the literature. In the context of treatment of injuries of the knee joint cartilage, the second-generation autologous chondrocyte transplant is a consolidated surgical method alternative to other techniques. Our experience with the transplantation of chondrocytes has had exceptional clinical results. We report 2 complete cases of a group of 22 in knee and ankle. These 2 cases had histological and instrumental evaluation. We cannot express conclusions, but can only make considerations, stating that, with the clinical functional result being equal, we obtained an excellent macroscopic result in both cases of second look. Autologous chondrocyte implantation (ACI) is a multiple surgical procedure with expensive chondrocyte culture, but even with this limitation, we think that it must be the choice in treating chondral lesions, especially in young patients. PMID:26055026

  12. Evaluation of stereo matching costs on images with radiometric differences.

    PubMed

    Hirschmller, Heiko; Scharstein, Daniel

    2009-09-01

    Stereo correspondence methods rely on matching costs for computing the similarity of image locations. We evaluate the insensitivity of different costs for passive binocular stereo methods with respect to radiometric variations of the input images. We consider both pixel-based and window-based variants like the absolute difference, the sampling-insensitive absolute difference, and normalized cross correlation, as well as their zero-mean versions. We also consider filters like LoG, mean, and bilateral background subtraction (BilSub) and nonparametric measures like Rank, SoftRank, Census, and Ordinal. Finally, hierarchical mutual information (HMI) is considered as pixelwise cost. Using stereo data sets with ground-truth disparities taken under controlled changes of exposure and lighting, we evaluate the costs with a local, a semiglobal, and a global stereo method. We measure the performance of all costs in the presence of simulated and real radiometric differences, including exposure differences, vignetting, varying lighting, and noise. Overall, the ranking of methods across all data sets and experiments appears to be consistent. Among the best costs are BilSub, which performs consistently very well for low radiometric differences; HMI, which is slightly better as pixelwise matching cost in some cases and for strong image noise; and Census, which showed the best and most robust overall performance. PMID:19574620

  13. Preliminary radiometric calibration assessment of ALOS AVNIR-2

    USGS Publications Warehouse

    Bouvet, M.; Goryl, P.; Chander, G.; Santer, R.; Saunier, S.

    2008-01-01

    This paper summarizes the activities carried out in the frame of the data quality activities of the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) sensor onboard the Advanced Land Observing Satellite (ALOS). Assessment of the radiometric calibration of the AVNIR-2 multi-spectral imager is achieved via three intercomparisons to currently flying sensors over the Libyan desert, during the first year of operation. AU three methodologies indicate a slight underestimation of AVNIR-2 in band 1 by 4 to 7% with respect to other sensors radiometric scale. Band 2 does not show any obvious bias. Results for band 3 are affected by saturation due to inappropriate gain setting. Two methodologies indicate no significant bias in band 4. Preliminary results indicate possible degradations of the AVNIR-2 channels, which, when modeled as an exponentially decreasing functions, have time constants of respectively 13.2 %.year-1, 8.8%.year-1 and 0.1%.year-1 in band 1, 2 and 4 (with respect to the radiometric scale of the MEdium Resolution Imaging Spectrometer, MERIS). Longer time series of AVNIR-2 data are needed to draw final conclusions. ?? 2007 IEEE.

  14. A Preliminary Analysis of LANDSAT-4 Thematic Mapper Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Justice, C.; Fusco, L.; Mehl, W.

    1985-01-01

    The NASA raw (BT) product, the radiometrically corrected (AT) product, and the radiometrically and geometrically corrected (PT) product of a TM scene were analyzed examine the frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band. The analyses were performed on a series of image subsets from the full scence. Results are presented from one 1024 c 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. From this cursory examination of one of the first seven channel TM data sets, it would appear that the radiometric performance of the system is most satisfactory and largely meets pre-launch specifications. Problems were noted with Band 5 Detector 3 and Band 2 Detector 4. Differences were observed between forward and reverse scan detector responses both for the BT and AT products. No systematic variations were observed between odd and even detectors.

  15. On the estimation of snow depth from microwave radiometric measurements

    NASA Technical Reports Server (NTRS)

    Wang, James R.; Chang, Alfred T. C.; Sharma, Awdhesh K.

    1992-01-01

    Multiple-channel microwave radiometric measurements made over Alaska at aircraft (near 90 and 183 GHz) and satellite (at 37 and 85 GHz) altitudes are used to study the effect of atmospheric absorption on the estimation of snow depth. The estimation is based on the radiative transfer calculations using an early theoretical model of Mie scattering of single-size particles. It is shown that the radiometric correction for the effect of atmospheric absorption is important even at 37 GHz for a reliable estimation of snow depth. Under a dry atmosphere and based on single-frequency radiometric measurements, the underestimation of snow depth could amount to 50 percent at 85 GHz and 20-30 percent at 37 GHz if the effect of atmospheric absorption is not taken into account. The snow depths estimated from the 90-GHz aircraft and 85-GHz satellite measurements are found to be in reasonable agreement. However, there is a discrepancy in the snow depths estimated from the 37-GHz (at both vertical and horizontal polarizations) and 85-GHz satellite measurements.

  16. Laboratory-Based BRDF Calibration of Radiometric Tarps

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi T.; Butler, James J.

    2007-01-01

    The current study provides the remote sensing community with important high accuracy laboratory-based BRDF calibration of radiometric tarps. The results illustrate the dependence of tarps' weft and warp threads orientation on BRDF. The study was done at incident angles of 0deg, 10deg, and 30deg; scatter zenith angles from 0deg to 60deg, and scatter azimuth angles of 0deg, 45deg, 90deg, 135deg, and 180deg. The wavelengths were 485nm, 550nm, 633nm and 800nm. The dependence is well defined at all measurement geometries and wavelengths. It can be as high as 8% at 0deg incident angle and 2% at 30deg incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps is reported. The backward scatter is well pronounced for the white samples. The black sample has well pronounced forward scatter. The BRDF characterization of radiometric tarps can be successfully extended to other structured surface fabric samples. The results are NIST traceable.

  17. User's guide to the Radiometric Age Data Bank (RADB)

    USGS Publications Warehouse

    Zartman, Robert Eugene; Cole, James C.; Marvin, Richard F.

    1976-01-01

    The Radiometric Age Data Bank (RADB) has been established by the U.S. Geological Survey, as a means for collecting and organizing the estimated 100,000 radiometric ages presently published for the United States. RADB has been constructed such that a complete sample description (location, rock type, etc.), literature citation, and extensive analytical data are linked to form an independent record for each sample reported in a published work. Analytical data pertinent to the potassium-argon, rubidium-strontium, uranium-thorium-lead, lead-alpha, and fission-track methods can be accommodated, singly or in combinations, for each record. Data processing is achieved using the GIPSY program (University of Oklahoma) which maintains the data file and builds, updates, searches, and prints the records using simple yet versatile command statements. Searching and selecting records is accomplished by specifying the presence, absence, or (numeric or alphabetic) value of any element of information in the data bank, and these specifications can be logically linked to develop sophisticated searching strategies. Output is available in the form of complete data records, abbreviated tests, or columnar tabulations. Samples of data-reporting forms, GIPSY command statements, output formats, and data records are presented to illustrate the comprehensive nature and versatility of the Radiometric Age Data Bank.

  18. Dating human bone: is racemization dating species-specific?

    PubMed

    Moini, Mehdi; Rollman, Christopher M; France, Christine A M

    2013-12-01

    Our recently developed dating technique based on the racemization rate of aspartic acid was applied to dating human bone, as well as that of other mammals, utilizing capillary electrophoresis mass spectrometry. First, several well-dated (mostly (14)C-dated and with strong archeological evidence) human bones ranging in age from 150 to ~10,000 years were used to develop a calibration curve for human bone. The D/L ratio of aspartic acid for these specimens ranged from 2.4% to ~10%, with a correlation coefficient of better than 0.99, indicating a strong linear relationship between the d/l ratio of aspartic acid and the age of the specimens. This calibration curve can now be used to date human archeological specimens of unknown age, up to ~10,000 years. However, when the technique was applied to well-dated mixed species of larger mammal bones such as bison, whale, llama, etc., the calibration curve showed a slower rate of racemization with a lower correlation (0.88). As additional large mammal bones with less certain age (i.e., using archeological evidence alone with no (14)C-dating) were dated the correlation coefficient decreased to 0.70. The correlation coefficient decreased further to 0.58 when the racemization data from all mammals (including human) were added to the calibration curve, indicating the importance of using well-dated, species-specific specimens for forming a calibration curve. This conclusion is consistent with our previously published calibration curve for a single species of silk (Bombyx mori), which followed the expected reversible first-order kinetics. These results support species specificity of amino acid racemization dating. PMID:24156614

  19. Radiometric stability of the Multi-angle Imaging SpectroRadiometer (MISR) following 15 years on-orbit

    NASA Astrophysics Data System (ADS)

    Bruegge, Carol J.; Val, Sebastian; Diner, David J.; Jovanovic, Veljko; Gray, Ellyn; Di Girolamo, Larry; Zhao, Guangyu

    2014-09-01

    The Multi-angle Imaging SpectroRadiometer (MISR) has successfully operated on the EOS/ Terra spacecraft since 1999. It consists of nine cameras pointing from nadir to 70.5 view angle with four spectral channels per camera. Specifications call for a radiometric uncertainty of 3% absolute and 1% relative to the other cameras. To accomplish this, MISR utilizes an on-board calibrator (OBC) to measure camera response changes. Once every two months the two Spectralon panels are deployed to direct solar-light into the cameras. Six photodiode sets measure the illumination level that are compared to MISR raw digital numbers, thus determining the radiometric gain coefficients used in Level 1 data processing. Although panel stability is not required, there has been little detectable change in panel reflectance, attributed to careful preflight handling techniques. The cameras themselves have degraded in radiometric response by 10% since launch, but calibration updates using the detector-based scheme has compensated for these drifts and allowed the radiance products to meet accuracy requirements. Validation using Sahara desert observations show that there has been a drift of ~1% in the reported nadir-view radiance over a decade, common to all spectral bands.

  20. Dating sediments using luminescence signals

    SciTech Connect

    Wintle, A. )

    1993-05-01

    Before siting a nuclear power station or a nuclear waste repository, it is necessary to establish that the area has been free of earthquake activity for a sufficient period of time. Evidence of past earthquake activity is often provided by faults in surface sediments. Age limits for fault formation can be set by obtaining the depositional ages of the sediment unit in which the fault was formed and the overlying sediment. A useful technique would be one that dating could be applied to the mineral grains that make up the sediments and that would give the time that has passed since the grains were blown or washed into position. Luminescence dating techniques, of which the most well known is thermo-luminescence (TL), provide such information. This approach has been successful in dating movement on the Wasatch Fault in Utah. A combination of TL and radiocarbon dates indicated that three faulting events had occurred within the past 5000 years. 2 refs., 1 fig.

  1. Ar-Ar Dating of Martian Chassignites, NWA2737 and Chassigny, and Nakhlite MIL03346

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Garrison, D. H.

    2006-01-01

    Until recently only three nakhlites and one chassignite had been identified among martian meteorites. These four exhibit very similar radiometric ages and cosmic ray exposure (CRE) ages, indicating that they may have derived from a common location on Mars and were ejected into space by a single impact. This situation is quite different from that of martian shergottites, which exhibit a range of radiometric ages and CRE ages (1). Recently, several new nakhlites and a new martian dunite (NWA2737) have been recognized. Here we report our results of Ar-39-Ar-40 dating for the MIL03346 nakhlite and the NWA2737 "chassignite", along with new results on Chassigny.

  2. 210Pb dating

    USGS Publications Warehouse

    Swarzenski, Peter W.

    2014-01-01

    Roughly fifty years ago, a small group of scientists from Belgium and the United States, trying to better constrain ice sheet accumulation rates, attempted to apply what was then know about environmental lead as a potential geochronometer. Thus Goldberg (1963) developed the first principles of the 210Pb dating method, which was soon followed by a paper by Crozaz et al. (1964), who examined accumulation history of Antarctic snow using 210Pb. Shortly thereafter, Koide et al. (1972, 1973) adapted this technique to unravel sediment deposition and accumulation records in deep-sea environments. Serendipitously, they chose to work in a deep basin off California, where an independent and robust age model had already been developed. Krishanswami et al. (1971) extended the use of this technique to lacustrine deposits to reconstruct depositional histories of lake sediment, and maybe more importantly, contaminant inputs and burial. Thus, the powerful tool for dating recent (up to about one century old) sediment deposits was established and soon widely adopted. Today almost all oceanographic or limnologic studies that address recent depositional reconstructions employ 210Pb as one of several possible geochronometers (Andrews et al., 2009; Gale, 2009; Baskaran, 2011; Persson and Helms, 2011). This paper presents a short overview of the principles of 210Pb dating and provides a few examples that illustrate the utility of this tracer in contrasting depositional systems. Potential caveats and uncertainties (Appleby et al., 1986; Binford, 1990; Binford et al., 1993; Smith, 2001; Hancock et al., 2002) inherent to the use and interpretation of 210Pb-derived age-models are also introduced. Recommendations as to best practices for most reliable uses and reporting are presented in the summary.

  3. Millennial-scale varnish microlamination dating of late Pleistocene geomorphic features in the drylands of western USA

    NASA Astrophysics Data System (ADS)

    Liu, Tanzhuo; Broecker, Wallace S.

    2013-04-01

    Varnish microlamination (VML) dating is a climate-based correlative age determination technique used to correlate and date various geomorphic features in deserts. In this study, we establish a generalized late Pleistocene (18-74 ka) millennial-scale microlamination sequence in fine-grained, fast-accumulating rock varnish for the drylands of western USA, radiometrically calibrate the sequence and correlate it with the ?18O record in the GISP2 Greenland ice core. We then use this climate-correlated varnish microstratigraphy to estimate surface exposure ages for radiometrically dated late Pleistocene geomorphic features in the study region. The VML dating of debris flow deposits on the Sehoo recessional shorelines of Lake Lahontan at the Jessup embayment of central Nevada yields a minimum-limiting age of 14.95-15.95 ka, in good agreement with a calibrated 14C age of 15.22 0.12 ka for the timing of the lake recession. The VML dating of a giant ejecta block on the rim of Meteor Crater in northern Arizona yields a minimum-limiting age of 49.15 ka, closely matching a thermoluminescence (TL) age of 49 3 ka and slightly younger than a recently updated cosmogenic 36Cl age of 56.0 2.4 ka for the meteor impact event. The VML dating of distal Q2c fan surfaces on Hanaupah Canyon alluvial fan in Death Valley, California, yields a minimum-limiting age of 73.55 ka, in accord with cosmogenic 36Cl depth-profile ages of 66 + 22/-14 ka and 72 + 24/- 20 ka for the same fan deposits. The close agreement between the VML age estimates and the independently derived radiometric ages for these geomorphic features attests to the validity and reliability of millennial-scale VML dating. To further assess its potential in desert geomorphological research, we use the VML method to study alluvial-fan responses to millennial-scale climatic changes. The VML dating of a small tributary fan in Death Valley reveals two episodes of fan aggradation, one ceasing at 73.55-86.75 ka during the dry period of the last interglacial (MIS 5a) and the other finishing at 66.15 ka during the wet period of the last glacial (MIS 4). The VML and 36Cl dating of the distal Q2c fan surfaces on Hanaupah Canyon fan reveal two episodes of large-scale fan aggradation ended at 72 + 24/- 20 ka and 73.55 ka during the wet period of MIS 4. Fanhead incision and associated within-channel or fantoe aggradation are found to take place during the relatively dry period of the glacial-to-interglacial climatic transition (12-24 ka) and the Holocene interglacial dry period (0-12 ka). These data indicate that, on the millennial to sub-Milankovitch timescale (~ 103-104 years), fan aggradation is a discrete sedimentational process under various climatic conditions. Because fan aggradation is ultimately controlled by the intensity and frequency of precipitation events - which in turn are modulated by major climatic oscillations such as Heinrich events, Dansgaard/Oeschger (DO) events, and glacial/interglacial shifts - these major climatic changes could be the pacemaker of regionally contemporaneous large-area fan segmentation.

  4. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    SciTech Connect

    Westwater, Edgeworth

    2011-05-06

    The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of this contract, we participated in another ARM-sponsored experiment at the NSA during February-March 2007. This experiment is called the Radiative Heating in Underexplored Bands Campaign (RHUBC) and the GSR was operated successfully for the duration of the campaign. One of the principal goals of the experiment was to provide retrievals of water vapor during PWV amounts less than 2 mm and to compare GSR data with ARM radiometers and radiosondes. A secondary goal was to compare the radiometric response of the microwave and millimeter wavelength radiometers to water and ice clouds. In this final report, we will include the separate progress reports for each of the three years of the project and follow with a section on major accomplishments of the project.

  5. Novel Hyperspectral Sun Photometer for Satellite Remote Sensing Data Radiometric Calibration and Atmospheric Aerosol Studies

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Ryan, Robert E.; Holekamp, Kara; Harrington, Gary; Frisbie, Troy

    2006-01-01

    A simple and cost-effective, hyperspectral sun photometer for radiometric vicarious remote sensing system calibration, air quality monitoring, and potentially in-situ planetary climatological studies, was developed. The device was constructed solely from off the shelf components and was designed to be easily deployable for support of short-term verification and validation data collects. This sun photometer not only provides the same data products as existing multi-band sun photometers, this device requires a simpler setup, less data acquisition time and allows for a more direct calibration approach. Fielding this instrument has also enabled Stennis Space Center (SSC) Applied Sciences Directorate personnel to cross calibrate existing sun photometers. This innovative research will position SSC personnel to perform air quality assessments in support of the NASA Applied Sciences Program's National Applications program element as well as to develop techniques to evaluate aerosols in a Martian or other planetary atmosphere.

  6. Upgrading a gravity field recovery software to satellite laser ranging and radiometric tracking data

    NASA Astrophysics Data System (ADS)

    Lcher, Anno; Kusche, Jrgen

    2013-04-01

    Since about a decade, the Institute of Geodesy and Geoinformation at Bonn takes an active part in the computation of global gravity field models from satellite-to-satellite tracking data. Based on extensive software developments, internationally accepted models such as ITG-CHAMP01, ITG-GRACE03 and ITG-GRACE2010 have been published. The Bonn software is now being upgraded for dealing with terrestrial observations from satellite laser ranging and radiometric tracking techniques. To cope with this data types a change in the observational model is needed, but also a change in the core algorithm switching from a short arc approach to a more classical procedure which improves orbit and force parameters in an iterative way. The presentation will give an overview of the updated software architecture and show first results from laser ranging to the LAGEOS satellites and laser and radio tracking to the Lunar Reconnaissance Orbiter.

  7. Dating and Marriage

    MedlinePLUS

    ... Marriage Subscribe Translate Text Size Print Dating and Marriage Dating and Marriage If you are living with HIV, you may ... testing site near you. Friends and Family Dating & Marriage Family Planning Mixed-Status Couples Related Topics on ...

  8. Radioactive Dating: A Method for Geochronology.

    ERIC Educational Resources Information Center

    Rowe, M. W.

    1985-01-01

    Gives historical background on the discovery of natural radiation and discusses various techniques for using knowledge of radiochemistry in geochronological studies. Indicates that of these radioactive techniques, Potassium-40/Argon-40 dating is used most often. (JN)

  9. New U-series dates at the Caune de l'Arago, France

    USGS Publications Warehouse

    Falgueres, Christophe; Yokoyama, Y.; Shen, G.; Bischoff, J.L.; Ku, T.-L.; de Lumley, Henry

    2004-01-01

    In the beginning of the 1980s, the Caune de l'Arago was the focus of an interdisciplinary effort to establish the chronology of the Homo heidelbergensis (Preneandertals) fossils using a variety of techniques on bones and on speleothems. The result was a very large spread of dates particularly on bone samples. Amid the large spread of results, some radiometric data on speleothems showed a convergence in agreement with inferences from faunal studies. We present new U-series results on the stalagmitic formation located at the bottom of Unit IV (at the base of the Upper Stratigraphic Complex). Samples and splits were collaboratively analyzed in the four different laboratories with excellent interlaboratory agreement. Results show the complex sequence of this stalagmitic formation. The most ancient part is systematically at internal isotopic equilibrium (>350 ka) suggesting growth during or before isotopic stage 9, representing a minimum age for the human remains found in Unit III of the Middle Stratigraphical Complex which is stratigraphically under the basis of the studied stalagmitic formation. Overlaying parts of the speleothem date to the beginning of marine isotope stages 7 and 5. ?? 2003 Elsevier Ltd. All rights reserved.

  10. New U-series dates at the Caune de l'Arago, France

    USGS Publications Warehouse

    Falgueres, Christophe; Yokoyama, Y.; Shen, G.; Bischoff, J.L.; Ku, T.-L.; de Lumley, Henry

    2004-01-01

    In the beginning of the 1980s, the Caune de l'Arago was the focus of an interdisciplinary effort to establish the chronology of the Homo heidelbergensis (Preneandertals) fossils using a variety of techniques on bones and on speleothems. The result was a very large spread of dates particularly on bone samples. Amid the large spread of results, some radiometric data on speleothems showed a convergence in agreement with inferences from faunal studies. We present new U-series results on the stalagmitic formation located at the bottom of Unit IV (at the base of the Upper Stratigraphic Complex). Samples and splits were collaboratively analyzed in the four different laboratories with excellent interlaboratory agreement. Results show the complex sequence of this stalagmitic formation. The most ancient part is systematically at internal isotopic equilibrium (>350 ka) suggesting growth during or before isotopic stage 9, representing a minimum age for the human remains found in Unit III of the Middle Stratigraphical Complex which is stratigraphically under the basis of the studied stalagmitic formation. Overlaying parts of the speleothem date to the beginning of marine isotope stages 7 and 5. ?? 2003 Elsevier Science Ltd. All rights reserved.

  11. Radiometric packaging of uncooled microbolometer FPA arrays for space applications

    NASA Astrophysics Data System (ADS)

    Garca-Blanco, S.; Cote, P.; Leclerc, M.; Blanchard, N.; Desroches, Y.; Caron, J.-S.; Ngo Phong, L.; Chateauneuf, F.; Pope, T.

    2009-02-01

    INO has extensive experience in the design and fabrication of focal plane arrays (FPAs) of uncooled microbolometers. In particular, the FPA of 5123 microbolometers, developed in collaboration with the Canadian Space Agency (CSA), has been selected for use in the NIRST (New Infrared Sensor Technology) radiometer of the SAC-D Aquarius mission. The FPA has been designed for pushbroom scanning of the Earth to provide radiometric data in the mid- and long-wave infrared for the monitoring of fires as well as thermal mapping of ocean temperature. Uncooled microbolometer detectors are suited for space applications due to their low power consumption while still exhibiting adequate performance. Furthermore, the spectral range of their response could be tuned from the mid- to the far-infrared to meet different mission requirements. In order to ensure that the detector receives only the thermal contribution from the desired target and to minimize radiometric error due to variation of the temperature of the surrounding during the measurements, a radiometric package is required. In a radiometric package the detector environment is thermally stabilized by means of a temperature controlled radiation shield. The radiation shield should also be designed to prevent stray radiation from reaching the detector. Under the Space Technology Development Program of the CSA, INO has designed, assembled and tested a radiometric package in order to characterize its performance and compatibility with the space environment. The operating spectral band is defined by the spectral characteristics of a bandpass filter placed in front of the FPA. For typical space missions, the package must pass standard environmental tests without degradation of its performance (thermal cycling from -55 to +85 C according to MIL-STD-810, random acceleration up to 14 G RMS from 20-2000 Hz and shock up to 75 G). In order to ensure reliability in those conditions while maintaining optimum performance, an adequate selection of materials is necessary. In this paper, INO's radiometric packaging technology for uncooled microbolometer FPA's will be presented. The selection of materials will be discussed and the final choices presented based on thermal simulations and experimental data. The effects of different design parameters on the performance, such as material, shape and thickness of radiation shield and choice of adhesive have been studied. An instantaneous noise equivalent temperature difference (NETD) of ~ 20 mK was obtained under the measurement conditions (broadband LWIR, 140 ms integration time, f/1 optics, characterization in flood exposure). The design of the package reduced the contribution of environmental temperature variations on the offset of the sensor. The equivalent response of the package varied less than 0.08 C per degree of variation of the temperature of the package. The package also showed low sensitivity to stray radiation as a result of the effectiveness of the radiation shield design. The device successfully passed the prescribed environmental tests without degradation of performance.

  12. Framework for preparing and performing absolute radiometric measurements using electrooptical instruments for the earth observations

    NASA Astrophysics Data System (ADS)

    Panfilov, A. S.; Gavrilov, V. R.; Sapritsky, V. I.

    2014-12-01

    The complex of measurements necessary for high-quality radiometric measurements of the Earth to be performed using space electrooptical instruments, including hyperspectrometric instruments, has been considered. This complex was developed in order to maintain the uniformity of measurements according to Russian legislation. In addition to organizational measures, it is necessary to determine the interrelation between radiometric data and geophysical parameters received using these data and to solve the methodological problems of the Earth observation instrument (EOI) radiometric calibration and in-orbit verification of EOI radiometric characteristics. The considered approaches are largely close to the statements of the international document "Quality Assurance Framework for Earth ObservationQA4EO".

  13. Radiometric calibration of digital cameras using Gaussian processes

    NASA Astrophysics Data System (ADS)

    Schall, Martin; Grunwald, Michael; Umlauf, Georg; Franz, Matthias O.

    2015-05-01

    Digital cameras are subject to physical, electronic and optic effects that result in errors and noise in the image. These effects include for example a temperature dependent dark current, read noise, optical vignetting or different sensitivities of individual pixels. The task of a radiometric calibration is to reduce these errors in the image and thus improve the quality of the overall application. In this work we present an algorithm for radiometric calibration based on Gaussian processes. Gaussian processes are a regression method widely used in machine learning that is particularly useful in our context. Then Gaussian process regression is used to learn a temperature and exposure time dependent mapping from observed gray-scale values to true light intensities for each pixel. Regression models based on the characteristics of single pixels suffer from excessively high runtime and thus are unsuitable for many practical applications. In contrast, a single regression model for an entire image with high spatial resolution leads to a low quality radiometric calibration, which also limits its practical use. The proposed algorithm is predicated on a partitioning of the pixels such that each pixel partition can be represented by one single regression model without quality loss. Partitioning is done by extracting features from the characteristic of each pixel and using them for lexicographic sorting. Splitting the sorted data into partitions with equal size yields the final partitions, each of which is represented by the partition centers. An individual Gaussian process regression and model selection is done for each partition. Calibration is performed by interpolating the gray-scale value of each pixel with the regression model of the respective partition. The experimental comparison of the proposed approach to classical flat field calibration shows a consistently higher reconstruction quality for the same overall number of calibration frames.

  14. Radiometric calibration of the Landsat MSS sensor series

    USGS Publications Warehouse

    Helder, Dennis L.; Karki, Sadhana; Bhatt, Rajendra; Micijevik, Esad; Aaron, David; Jasinski, Benjamin

    2012-01-01

    Multispectral remote sensing of the Earth using Landsat sensors was ushered on July 23, 1972, with the launch of Landsat-1. Following that success, four more Landsat satellites were launched, and each of these carried the Multispectral Scanner System (MSS). These five sensors provided the only consistent multispectral space-based imagery of the Earth's surface from 1972 to 1982. This work focuses on developing both a consistent and absolute radiometric calibration of this sensor system. Cross-calibration of the MSS was performed through the use of pseudoinvariant calibration sites (PICSs). Since these sites have been shown to be stable for long periods of time, changes in MSS observations of these sites were attributed to changes in the sensors themselves. In addition, simultaneous data collections were available for some MSS sensor pairs, and these were also used for cross-calibration. Results indicated substantial differences existed between instruments, up to 16%, and these were reduced to 5% or less across all MSS sensors and bands. Lastly, this paper takes the calibration through the final step and places the MSS sensors on an absolute radiometric scale. The methodology used to achieve this was based on simultaneous data collections by the Landsat-5 MSS and Thematic Mapper (TM) instruments. Through analysis of image data from a PICS location and through compensating for the spectral differences between the two instruments, the Landsat-5 MSS sensor was placed on an absolute radiometric scale based on the Landsat-5 TM sensor. Uncertainties associated with this calibration are considered to be less than 5%.

  15. BOREAS TE-18, 30-m, Radiometrically Rectified Landsat TM Imagery

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David

    2000-01-01

    The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 21-Jun-1995. the 23 rectified images cover the period of 07-Jul-1985 to 18 Sep-1994 in the SSA and from 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (199 1). The original Landsat TM data were received from CCRS for use in the BOREAS project. The data are stored in binary image-format files. Due to the nature of the radiometric rectification process and copyright issues, these full-resolution images may not be publicly distributed. However, a spatially degraded 60-m resolution version of the images is available on the BOREAS CD-ROM series. See Sections 15 and 16 for information about how to possibly acquire the full resolution data. Information about the full-resolution images is provided in an inventory listing on the CD-ROMs. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

  16. In-flight absolute radiometric calibration of the thematic mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

    1983-01-01

    The TM multispectral scanner system was calibrated in an absolute manner before launch. To determine the temporal changes of the absolute radiometric calibration of the entire system, spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM collections over White Sands, New Mexico. By entering the measured values in an atmospheric radiative transfer program, the radiance levels of the in four of the spectral bands of the TM were determined. Tables show values for the reflectance of snow at White Sands measured by a modular 8 channel radiometer, and values for exoatmospheric irradiance within the TM passbands, calculated for the Earth-Sun distance using a solar radiometer.

  17. Synchrotron ultraviolet radiation facility (SURF II) radiometric instrumentation calibration facility

    SciTech Connect

    Furst, M.L.; Graves, R.M.; Madden, R.P. )

    1993-11-01

    Spectrometer calibrations have been performed at the National Institute of Standards and Technology (formerly the National Bureau of Standards) for over 10 yr using the calculable synchrotron radiation from the SURF 2 electron storage ring. SURF 2 is not a high-performance storage ring that can operate at electron energies up to 300 MeV and with over 250 mA of stored current. One beam line, operationally supported by the National Aeronautics and Space Administration (NASA), is dedicated for use as a radiometric instrumentation calibration facility for outside users.

  18. A radiometric interpretive legend for Landsat digital thematic maps

    USGS Publications Warehouse

    Robinove, Charles J.

    1977-01-01

    A legend is suggested for use with computer-generated thematic maps made from Landsat digital data that designates some of the radiometric characteristics of each thematic map unit as well as the described terrain attributes of each map unit. The relationship between spectral band and radiance for each map unit is shown by a two-dimensional polygon with the four Landsat multispectral scanner bands plotted on the ordinate and radiance levels on the abscissa. The resulting shape is colored to correspond with the map unit color, thus facilitating the recognition and understanding of the computer-generated map units.

  19. Spectrally and Radiometrically Stable, Wideband, Onboard Calibration Source

    NASA Technical Reports Server (NTRS)

    Coles, James B.; Richardson, Brandon S.; Eastwood, Michael L.; Sarture, Charles M.; Quetin, Gregory R.; Porter, Michael D.; Green, Robert O.; Nolte, Scott H.; Hernandez, Marco A.; Knoll, Linley A.

    2013-01-01

    The Onboard Calibration (OBC) source incorporates a medical/scientific-grade halogen source with a precisely designed fiber coupling system, and a fiber-based intensity-monitoring feedback loop that results in radiometric and spectral stabilities to within less than 0.3 percent over a 15-hour period. The airborne imaging spectrometer systems developed at the Jet Propulsion Laboratory incorporate OBC sources to provide auxiliary in-use system calibration data. The use of the OBC source will provide a significant increase in the quantitative accuracy, reliability, and resulting utility of the spectral data collected from current and future imaging spectrometer instruments.

  20. Radiometric calibrations of portable sources in the vacuum ultraviolet

    NASA Technical Reports Server (NTRS)

    Klose, Jules Z.; Bridges, J. Mervin; Ott, William R.

    1988-01-01

    The primary UV radiometric calibration standards of the Atomic and Plasma Radiation Division of the NBS are the hydrogen arc and the blackbody line arc. The secondary standards are the argon mini- and maxiarcs, and the deuterium arc lamp. Calibration methods involving both spectral radiance and irradiance, as well as the evaluation of their uncertainties, are discussed. Attention is given to the establishment of an irradiance scale, and the absolute spectral irradiance, measured as a function of wavelength, at a 50-cm distance from the field aperture for five different continuum sources.

  1. Correcting for nucleogenic ^{36}Cl in cosmogenic ^{36}Cl dating of volcanic rocks from the Erciyes volcano, Central Turkey

    NASA Astrophysics Data System (ADS)

    Sarikaya, M. A.; Zreda, M.; Desilets, D.; Ciner, A.; Sen, E.

    2006-12-01

    Many radiometric methods are suitable for dating lava flows, but none is reliable for routine dating of lava flows younger than 10 ky. The cosmogenic ^{36}Cl method seems promising because it can be applied to any type of rock and laboratory and analytical work is easy and fast. But low cosmogenic ^{36}Cl inventory (after short exposure duration), combined with possible large non-cosmogenic component, makes this technique difficult to apply in a routine fashion. We applied the ^{36}Cl method to date a lava flow and the 14C technique to date the associated ash flow from the Erciyes (Argaeus) volcano, central Turkey. The average of three cosmogenic ^{36}Cl ages is 7.3 \\mp 0.5 ky and the average of two radiocarbon ages is 9.5 \\mp 0.3 ky (calibrated using Calib 5.0). The difference could be due to the overestimation of the calculated nucleogenic ^{36}Cl, which makes up almost one-third of the measured ^{36}Cl. If the nucleogenic component were set to zero, the average ^{36}Cl age would be 10.3 \\mp 0.2 ky. Thus, the ^{36}Cl age should be in the range between 7.3 ky and 10.2 ky, which includes the 14C age near the upper end of the interval. Under the assumption that the 14C age is correct and that the nucleogenic ^{36}Cl has reached a secular equilibrium with the magma, the nucleogenic ^{36}Cl needed to reconcile the ^{36}Cl and 14C ages is only about one-fifth of that previously calculated. In order to investigate this disparity of ages and possible calculating errors of nucleogenic ^{36}Cl, we are analyzing rock samples from where we can directly measure nucleogenic component of ^{36}Cl. This work is important for developing better ways to estimate the nucleogenic ^{36}Cl, which will improve the accuracy of ^{36}Cl dating of young volcanic rocks.

  2. Automatic and improved radiometric correction of Landsat imagery using reference values from MODIS surface reflectance images

    NASA Astrophysics Data System (ADS)

    Pons, X.; Pesquer, L.; Cristbal, J.; Gonzlez-Guerrero, O.

    2014-12-01

    Radiometric correction is a prerequisite for generating high-quality scientific data, making it possible to discriminate between product artefacts and real changes in Earth processes as well as accurately produce land cover maps and detect changes. This work contributes to the automatic generation of surface reflectance products for Landsat satellite series. Surface reflectances are generated by a new approach developed from a previous simplified radiometric (atmospheric + topographic) correction model. The proposed model keeps the core of the old model (incidence angles and cast-shadows through a digital elevation model [DEM], Earth-Sun distance, etc.) and adds new characteristics to enhance and automatize ground reflectance retrieval. The new model includes the following new features: (1) A fitting model based on reference values from pseudoinvariant areas that have been automatically extracted from existing reflectance products (Terra MODIS MOD09GA) that were selected also automatically by applying quality criteria that include a geostatistical pattern model. This guarantees the consistency of the internal and external series, making it unnecessary to provide extra atmospheric data for the acquisition date and time, dark objects or dense vegetation. (2) A spatial model for atmospheric optical depth that uses detailed DEM and MODTRAN simulations. (3) It is designed so that large time-series of images can be processed automatically to produce consistent Landsat surface reflectance time-series. (4) The approach can handle most images, acquired now or in the past, regardless of the processing system, with the exception of those with extremely high cloud coverage. The new methodology has been successfully applied to a series of near 300 images of the same area including MSS, TM and ETM+ imagery as well as to different formats and processing systems (LPGS and NLAPS from the USGS; CEOS from ESA) for different degrees of cloud coverage (up to 60%) and SLC-off. Reflectance products have been validated with some example applications: time series robustness (for a pixel in a pseudoinvariant area, deviations are only 1.04% on average along the series), spectral signatures generation (visually coherent with the MODIS ones, but more similar between dates), and classification (up to 4 percent points better than those obtained with the original manual method or the CDR products). In conclusion, this new approach, that could also be applied to other sensors with similar band configurations, offers a fully automatic and reasonably good procedure for the new era of long time-series of spatially detailed global remote sensing data.

  3. Optimal spectral inversion of atmospheric radiometric measurements in the near-UV to near-IR range: A case study

    NASA Astrophysics Data System (ADS)

    Fussen, Didier; Vanhellemont, Filip; Bingen, Christine

    2002-01-01

    WWe present a general analysis of the error budget in the spectral inversion of atmospheric radiometric measurements. By focussing on the case of an occultation experiment, we simplify the problem through a reduced number of absorbers in a linearized formalism. However, our analysis is quite general and applies to many other situations. For a spectrometer having an infinite spectral resolution, we discuss the origin of systematic and random errors. In particular, the difficult case of aerosols is investigated and several inversion techniques are compared. We underline the importance of carefully simulating the spectral inversion as a function of the target constituent to be retrieved, and the required accuracy level.

  4. Temperature measurements behind reflected shock waves in air. [radiometric measurement of gas temperature in self-absorbing gas flow

    NASA Technical Reports Server (NTRS)

    Bader, J. B.; Nerem, R. M.; Dann, J. B.; Culp, M. A.

    1972-01-01

    A radiometric method for the measurement of gas temperature in self-absorbing gases has been applied in the study of shock tube generated flows. This method involves making two absolute intensity measurements at identical wavelengths, but for two different pathlengths in the same gas sample. Experimental results are presented for reflected shock waves in air at conditions corresponding to incident shock velocities from 7 to 10 km/s and an initial driven tube pressure of 1 torr. These results indicate that, with this technique, temperature measurements with an accuracy of + or - 5 percent can be carried out. The results also suggest certain facility related problems.

  5. A Preliminary Analysis of LANDSAT-4 Thematic Mapper Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Justice, C.; Fusco, L.; Mehl, W.

    1984-01-01

    Analysis was performed to characterize the radiometry of three Thematic Mapper (TM) digital products of a scene of Arkansas. The three digital products examined were the NASA raw (BT) product, the radiometrically corrected (AT) product and the radiometrically and geometrically corrected (PT) product. The frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band were examined on a series of image subsets from the full scene. The results are presented from one 1024 x 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. Bands 1, 2 and 5 of the sample area are presented. The subsets were extracted from the three digital data products to cover the same geographic area. This analysis provides the first step towards a full appraisal of the TM radiometry being performed as part of the ESA/CEC contribution to the NASA/LIDQA program.

  6. Blood culture cross contamination associated with a radiometric analyzer

    SciTech Connect

    Griffin, M.R.; Miller, A.D.; Davis, A.C.

    1982-04-01

    During a 9-day period in August 1980 in a New Jersey hospital, three pairs of consecutively numbered blood cultures from different patients were identified as positive for the same organism, for each pair, both cultures were positive in the same atmosphere, both organisms had the same sensitivities, and the second of each pair grew at least 2 days after the first and was the only positive blood culture obtained from the patient. When the hospital laboratory discontinued use of its radiometric culture analyzer for 15 days, no more consecutive pairs of positive cultures occurred. Subsequent use of the machine for 9 days with a new power unit but the original circuit boards resulted in one more similar consecutive pair (Staphylococcus epidermidis). After replacement of the entire power unit, there were no further such pairs. Examination of the machine by the manufacturer revealed a defective circuit board which resulted in inadequate needle sterilization. Laboratories which utilize radiometric analyzers should be aware of the potential for cross contamination. Recognition of such events requires alert microbiologists and infection control practitioners and a record system in the bacteriology laboratory designed to identify such clusters.

  7. Branching Ratios for The Radiometric Calibration of EUNIS-2012

    NASA Technical Reports Server (NTRS)

    Daw, Adrian N.; Bhatia, A. K.; Rabin, Douglas M.

    2012-01-01

    The Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument is a two-channel imaging spectrograph that observes the solar corona and transition region with high spectral resolution and a rapid cadence made possible by unprecedented sensitivity. The upcoming flight will incorporate a new wavelength channel covering the range 524-630 Angstroms, the previously-flown 300-370 Angstroms channel, and the first flight demonstration of cooled active pixel sensor (APS) arrays. The new 524-630 Angstrom channel incorporates a Toroidal Varied Line Space (TVLS) grating coated with B4C/Ir, providing broad spectral coverage and a wide temperature range of 0.025 to 10 MK. Absolute radiometric calibration of the two channels is being performed using a hollow cathode discharge lamp and NIST-calibrated AXUV-100G photodiode. Laboratory observations of He I 584 Angstroms and He II 304 Angstroms provide absolute radiometric calibrations of the two channels at those two respective wavelengths by using the AXUV photodiode as a transfer standard. The spectral responsivity is being determined by observing line pairs with a common upper state in the spectra of Ne I-III and Ar II-III. Calculations of A-values for the observed branching ratios are in progress.

  8. Accurate Radiometric Calibration using Mechanically-Shuttered CCD Systems

    NASA Astrophysics Data System (ADS)

    Hall, D.; Liang, D.

    Acquiring accurate radiometric measurements is an essential part of characterizing non-resolvable satellites. For instance, temporal photometric signatures provide information on characteristic size, reflectance, and stability, spin rate, etc., and with more detailed analysis, shape and attitude. Multi-color photometric measurements provide information on material composition and the effects of space weathering. Thermal infrared radiometry provides gray-body temperatures and emissivity properties. Many of these methods rely on accurate radiometric calibration. For CCD systems, the calibration process generally entails removing bias and dark signals from the raw frames, dividing by a flat-field frame to account for non-uniformities, and applying a sensitivity factor to convert the remaining signal into photon-flux or energy-flux units. However, when using mechanically-shuttered camera systems, another effect must be accounted for to obtain accurately calibrated data: the finite time required for the mechanical shutter to open and close. Measurements for both two-bladed and iris mechanical shutters indicate that neglecting this effect can lead to calibration errors of 10% or more in short-duration exposures. We present methods for measuring this effect, either in a laboratory setting or with the instrument mounted on a telescope, and the additional steps required to calibrate CCD data.

  9. Radiometric Characterization of Hyperspectral Imagers using Multispectral Sensors

    NASA Technical Reports Server (NTRS)

    McCorkel, Joel; Kurt, Thome; Leisso, Nathan; Anderson, Nikolaus; Czapla-Myers, Jeff

    2009-01-01

    The Remote Sensing Group (RSG) at the University of Arizona has a long history of using ground-based test sites for the calibration of airborne and satellite based sensors. Often, ground-truth measurements at these test sites are not always successful due to weather and funding availability. Therefore, RSG has also automated ground instrument approaches and cross-calibration methods to verify the radiometric calibration of a sensor. The goal in the cross-calibration method is to transfer the calibration of a well-known sensor to that of a different sensor, This work studies the feasibility of determining the radiometric calibration of a hyperspectral imager using multispectral a imagery. The work relies on the Moderate Resolution Imaging Spectroradiometer (M0DIS) as a reference for the hyperspectral sensor Hyperion. Test sites used for comparisons are Railroad Valley in Nevada and a portion of the Libyan Desert in North Africa. Hyperion bands are compared to MODIS by band averaging Hyperion's high spectral resolution data with the relative spectral response of M0DlS. The results compare cross-calibration scenarios that differ in image acquisition coincidence, test site used for the calibration, and reference sensor. Cross-calibration results are presented that show agreement between the use of coincident and non-coincident image pairs within 2% in most brands as well as similar agreement between results that employ the different MODIS sensors as a reference.

  10. Investigation of radiometric properties of the LANDSAT-4 multispectral scanner

    NASA Technical Reports Server (NTRS)

    Malila, W. A. (principal investigator); Rice, D. P.

    1983-01-01

    The radiometric data quality of the LANDSAT 4 multispectral scanner (MSS) was examined using several LANDSAT 4 frames. It was found that LANDSAT 4 MSS produces high-quality data of the caliber experienced with previous LANDSATS. For example, the detector equalization procedure worked well, leaving a residual banding effect of about 0.3 digital counts RMS, close to the theoretical minimum value of quantization error. Nevertheless, artifacts of the data were found, two of which were not experienced in previous MSS data. A low-level coherent noise effect was observed in all bands, with a magnitude of about 0.5 digital counts and a frequency of approximately 28 KHz (representing a wavelength of about 3.6 pixels); a substantial increase in processing complexity would be required to reduce this artifact in the data. Also, a substantial scan-length variation (of up to six pixels) was noted in MSS data when the TM sensor was operating; the LANDSAT 4 correction algorithms being applied routinely by the EROS Data Center to produce a p-type data should remove most of this variation. Between-satellite calibrations were examined in paired LANDSAT 3 and LANDSAT 4 MSS data sets, which were closely matched in acquisition time and place. Radiometric comparisons showed that all bands were highly linear in digital counts, and a well-determined linear transformation between the MSS's was established.

  11. A radiometric assay for bacterial growth detection and quantitative antibiotic testing

    SciTech Connect

    Boonkitticharoen, V.; Kirchner, P.T.; Ehrhardt, J.C.

    1984-01-01

    Buddemeyer's two-compartment radiometric assay for bacterial growth using respired C-14 carbon dioxide promised major advantages over other available methods, but limitations of the technique have restricted its application. Through a systemic study of relevant physical and chemical factors the authors sought to improve the assay for earlier detection of bacterial growth and to extend its use to measurement of antibiotic drug susceptibility and potency. A 35-fold improvement in count rate response was achieved by a) reversing growth and detector chambers to permit rigorous agitation, b) increasing NaOH quantity and using a supersaturated PPO solution, and c) adding detergent to stabilize NaOH-PPO contact. Bacterial growth may be detected as early as 1/2 hour after inoculation. For rapidly growing bacteria the growth rate constant is defined as the slope of the growth curve (log count rate vs. time). The validity of the growth behavior was verified by measuring growth at several inoculum sizes over 3 orders of magnitude using standard strains of S. aureus and E. coli. The growth rate constant proved to be independent of inoculum size. To test the merit of the system as an antibiotic assay, E. coli were exposed to doses of spectinomycin hydrochloride in the range which yielded a nonlinear dose-response relation by a turbidity assay. The test, however, showed a linear relation between growth rate constant and antibiotic dose. The results clearly indicate the radiometric growth rate assay to be a rapid, valid and objective assay for bacterial growth and antibiotic sensitivity.

  12. Evaluating Radiometric Measurements Using a Fixed 45 Degrees Responsivity and Zenith Angle Dependent Responsivities (Poster)

    SciTech Connect

    Dooraghi, M.; Habte, A.; Reda, I.; Sengupta, M.; Gotseff, P.; Andreas, A.; Anderberg, M.

    2014-03-01

    This poster seeks to demonstrate the importance and application of an existing but unused approach that ultimately reduces the uncertainty of radiometric measurements. Current radiometric data is based on a single responsivity value that introduces significant uncertainty to the data, however, through using responsivity as a function of solar zenith angle, the uncertainty could be decreased by 50%.

  13. Application of radiometric surface temperature for surface energy balance estimation: John Monteith's contributions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 25 years ago, Huband and Monteith paper’s investigating the radiative surface temperature and the surface energy balance of a wheat canopy, highlighted the key issues in computing fluxes with radiometric surface temperature. These included the relationship between radiometric and aerodynamic s...

  14. The Landsat Data Continuity Mission Operational Land Imager (OLI) Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Markham, Brian L.; Dabney, Philip W.; Murphy-Morris, Jeanine E.; Knight, Edward J.; Kvaran, Geir; Barsi, Julia A.

    2010-01-01

    The Operational Land Imager (OLI) on the Landsat Data Continuity Mission (LDCM) has a comprehensive radiometric characterization and calibration program beginning with the instrument design, and extending through integration and test, on-orbit operations and science data processing. Key instrument design features for radiometric calibration include dual solar diffusers and multi-lamped on-board calibrators. The radiometric calibration transfer procedure from NIST standards has multiple checks on the radiometric scale throughout the process and uses a heliostat as part of the transfer to orbit of the radiometric calibration. On-orbit lunar imaging will be used to track the instruments stability and side slither maneuvers will be used in addition to the solar diffuser to flat field across the thousands of detectors per band. A Calibration Validation Team is continuously involved in the process from design to operations. This team uses an Image Assessment System (IAS), part of the ground system to characterize and calibrate the on-orbit data.

  15. Influence of Leaf Area Index on the Radiometric Resistance to Heat Transfer

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Lee, Xuhui; Suyker, Andrew E.; Wen, Xuefa

    2016-01-01

    Sensible heat flux is an important component of the surface energy balance. Land surface models often use the radiative surface temperature instead of the aerodynamic temperature to predict the surface sensible flux, because the former is much easier to observe by remote sensing or to compute from the surface energy balance equation. Here, measurements from 44 FLUXNET sites are used to examine the stability and leaf area index ( LAI) dependence of the radiometric resistance, a resistance that should be included in the bulk transfer method if the radiometric temperature is used for the flux calculation. Results show that the radiometric resistance is much higher under stable conditions than under unstable conditions. In unstable conditions, the radiometric resistance is highly sensitive to LAI, decreasing exponentially as LAI increases. Omission of the radiometric resistance from the bulk transfer method causes a large overestimation in the sensible heat flux, especially for low- LAI surfaces and under unstable conditions.

  16. An overview of in-orbit radiometric calibration of typical satellite sensors

    NASA Astrophysics Data System (ADS)

    Zhou, G. Q.; Li, C. Y.; Yue, T.; Jiang, L. J.; Liu, N.; Sun, Y.; Li, M. Y.

    2015-06-01

    This paper reviews the development of in-orbit radiometric calibration methods in the past 40 years. It summarizes the development of in-orbit radiometric calibration technology of typical satellite sensors in the visible/near-infrared bands and the thermal infrared band. Focuses on the visible/near-infrared bands radiometric calibration method including: Lamp calibration and solar radiationbased calibration. Summarizes the calibration technology of Landsat series satellite sensors including MSS, TM, ETM+, OLI, TIRS; SPOT series satellite sensors including HRV, HRS. In addition to the above sensors, there are also summarizing ALI which was equipped on EO-1, IRMSS which was equipped on CBERS series satellite. Comparing the in-orbit radiometric calibration technology of different periods but the same type satellite sensors analyzes the similarities and differences of calibration technology. Meanwhile summarizes the in-orbit radiometric calibration technology in the same periods but different country satellite sensors advantages and disadvantages of calibration technology.

  17. Absolute ages from crater statistics: Using radiometric ages of Martian samples for determining the Martian cratering chronology

    NASA Technical Reports Server (NTRS)

    Neukum, G.

    1988-01-01

    In the absence of dates derived from rock samples, impact crater frequencies are commonly used to date Martian surface units. All models for absolute dating rely on the lunar cratering chronology and on the validity of its extrapolation to Martian conditions. Starting from somewhat different lunar chronologies, rather different Martian cratering chronologies are found in the literature. Currently favored models are compared. The differences at old ages are significant, the differences at younger ages are considerable and give absolute ages for the same crater frequencies as different as a factor of 3. The total uncertainty could be much higher, though, since the ratio of lunar to Martian cratering rate which is of basic importance in the models is believed to be known no better than within a factor of 2. Thus, it is of crucial importance for understanding the the evolution of Mars and determining the sequence of events to establish an unambiguous Martian cratering chronology from crater statistics in combination with clean radiometric ages of returned Martian samples. For the dating goal, rocks should be as pristine as possible from a geologically simple area with a one-stage emplacement history of the local formation. A minimum of at least one highland site for old ages, two intermediate-aged sites, and one very young site is needed.

  18. XRTD: An X-Windows based, real-time radiometric display and analysis system

    NASA Technical Reports Server (NTRS)

    Pollmeier, Vincent M.

    1993-01-01

    XRTD is a graphical user interface (GUI) based tool for monitoring real time radiometric spacecraft data. The tool is designed to allow the navigation analyst to both view and analyze the characteristics of Doppler and ranging data. This capability is critical if ground personnel wish to verify the correct performance of ongoing maneuvers. The raw tracking data is transferred from Deep Space Network (DSN) computers to a local workstation, where the predicted value for the observable is subtracted from the actual observed value to create a residual. The tool then allows the navigation analyst to rescale and replot the data using simple GUI techniques. The navigator may then perform a number of data analysis and modeling techniques on the resulting residuals to allow for the real time characterization of spacecraft events. These techniques include the modeling of maneuvers, the compression and differencing of data, and Fast Fourier transforms of the data. This tool has shortened the amount of time required for initial characterization of spacecraft maneuvers from several hours to a few minutes.

  19. Dating of Modern Human Evolution

    NASA Astrophysics Data System (ADS)

    Grun, R.

    Dating studies on palaoeanthropological sites is usually carried out on material associ- ated with the human remains, such as the sediment, charcoal or other fauna rather than the human specimen itself. The reason lies in the fact that most dating techniques are destructive and because the hominid remains are too rare to be sacrificed for dating. This indirect dating approach is in many cases not satisfactory, because: (i) the human remains are often buried into the sediments and the association with other materials is uncertain (e.g. Skhul, Qafzeh, etc.); (ii) faunal remains or minerals from the sediment are re-worked from older deposits (see e.g. present discussion of the age of the Homo erectus remains in Indonesia; (iii) the hominid fossils were discovered at a time when no careful excavations were carried out and it is impossible to correlate the specimen with other datable material (which applies tonearly 90% of all palaeoanthropological specimens). For example, the hominid burial site of Qafzeh in Israel has been dated by several independent dating laboratories with a multitude of methods. However, the data are still not accepted by some because the dating has not been carried out on the hominid specimen. Until recently, hominid fossils could only be dated by radiocarbon. This method reaches back to about 40,000 years. As a consequence, all the older fossils could not be analysed and many important questions in our understanding of human evolution could not be addressed. Human remains are scarce and extremely valuable, therefore any sort of destruction has to be kept to an absolute minimum. This is of particular importance in Australia where any human fossils are sacred. Thus, for the analysis of hominid material it was necessary to develop a more or less non-destructive techniques. This has been ac- complished in recent years by the application of ESR dating of tooth enamel and a combination of gamma spectrometric and TIMS U-series dating of bones. The exam- ples of Florisbad, Mungo 3, Shkul and Tabun are used to illustrate the potential and pitfalls of these methods in palaeoanthropology.

  20. Atmospheric measurement analysis for the Radiometric Calibration Test Site (RadCaTS)

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey

    2015-09-01

    The Radiometric Calibration Test Site (RadCaTS) was developed by the University of Arizona in the early 2000s to collect ground-based data in support of the calibration and validation of Earth-observing sensors. It uses the reflectance-based approach, which requires measurements of the atmosphere and surface reflectance. The measurements are used in MODTRAN to determine the at-sensor radiance for a given time and date. In the traditional reflectance-based approach, on-site personnel use an automated solar radiometer (ASR) to measure the atmospheric attenuation, but in the case of RadCaTS, an AERONET Cimel sun photometer is used to make atmospheric measurements. This work presents a comparison between the Cimel-derived atmospheric characteristics such as aerosol optical depth, the Angstrom exponent, and the columnar water vapor, to those derived using a traditional solar radiometer. The top-of-atmosphere radiance derived using the Cimel and ASR measurements are compared using Landsat 8 OLI bands as a test case for the period 2012-2014 to determine if any biases exist between the two methodologies.

  1. Laboratory for Radiokrypton Dating

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Bailey, K.; Jiang, W.; Müller, P.; O'Connor, T. P.; Zappala, J. C.

    2013-12-01

    Due to its simple production and transport processes in the terrestrial environment, the long-lived noble-gas isotope 81Kr (half-life = 230 kyr) is the ideal tracer for studying old water and ice in the age range of 10^5-10^6 years, a range beyond the reach of 14C. 81Kr dating, a concept pursued in the past four decades by numerous laboratories employing a variety of techniques, is now available for the first time to the earth science community at large. This is made possible by the development of ATTA-3 (Jiang et al., GCA 91, 1-6; 2012), an efficient and selective atom counter based on the Atom Trap Trace Analysis method (Chen et al., Science 286, 1139-1141; 1999). The instrument is capable of measuring both 81Kr/Kr and 85Kr/Kr ratios of environmental samples in the range of 10^-14-10^-10. For 81Kr-dating in the age range of 150 - 1,500 kyr, the required sample size is 5 - 10 micro-L STP of krypton gas, which can be extracted from approximately 100 - 200 kg of water or 40 - 80 kg of ice. For 85Kr/Kr analysis, the required sample size is generally smaller by an order of magnitude because of the isotope's higher initial abundance in the atmosphere. The Laboratory for Radiokrypton Dating is currently equipped to analyze up to 120 samples per year. With future equipment upgrades, this limit can be increased as demand grows. In the period since November 2011, the Laboratory has measured both 81Kr/Kr and 85Kr/Kr ratios in over 50 samples that had been extracted by collaborators from six different continents. The samples were from groundwater wells in the Great Artesian Basin (Australia), Guarani Aquifer (Brazil), and Locust Grove (Maryland); from brine wells of the Waste Isolation Pilot Plant (New Mexico); from geothermal steam vents in Yellowstone National Park; from near-surface ice at Taylor Glacier, Antarctica; and from deep mines in South Africa. Sample collection and purification was performed by groups including the University of Illinois at Chicago, University of Bern, and International Atomic Energy Agency. ATTA is a laser-based atom counting method, not a mass spectrometry method. A magneto-optical trap is used to capture neutral atoms (rather than ions) of the desired isotope using laser beams. A photo-sensor detects the laser induced fluorescence emitted by the individual trapped atoms. ATTA is unique among trace analysis techniques in that it is free of interferences from any other isotopes, isobars, atomic or molecular species. In an experiment demonstrating that ATTA-3 can analyze 39Ar/Ar ratios in environmental samples, no interference from other atomic or molecular species was observed at the 1x10^-16 level (Jiang et al., Phys. Rev. Lett. 106, 103001; 2011). This work proved the feasibility of performing 39Ar dating using the ATTA method. We are supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357, and by Argonne National Laboratory.

  2. Radiometric calibration and SNR calculation of a SWIR imaging telescope

    SciTech Connect

    Yilmaz, Ozgur; Turk, Fethi; Selimoglu, Ozgur

    2012-09-06

    Radiometric calibration of an imaging telescope is usually made using a uniform illumination sphere in a laboratory. In this study, we used the open-sky images taken during bright day conditions to calibrate our telescope. We found a dark signal offset value and a linear response coefficient value for each pixel by using three different algorithms. Then we applied these coefficients to the taken images, and considerably lowered the image non-uniformity. Calibration can be repeated during the operation of telescope with an object that has better uniformity than open-sky. Also SNR (Signal to Noise Ratio) of each pixel was calculated from the open-sky images using the temporal mean and standard deviations. It is found that SNR is greater than 80 for all pixels even at low light levels.

  3. Radiometric performance of the Viking Mars lander cameras

    NASA Technical Reports Server (NTRS)

    Huck, F. O.; Burcher, E. E.; Taylor, E. J.; Wall, S. D.

    1975-01-01

    The Viking lander cameras feature an array of 12 silicon photodiodes for electronic focus selection and multispectral imaging. Comparisons of absolute radiometric calibrations of the four cameras selected for the mission to Mars with performance predictions based on their design data revealed minor discrepancies. These discrepancies were caused primarily by the method used to calibrate the photosensor array and apparently also from light reflections internal to the array. The sensitivity and dynamic range of all camera channels are found to be sufficient for high quality pictures, providing that the commandable gains and offsets can be optimized for the scene radiance; otherwise, the quantization noise may be too high or the dynamic range too low for an adequate characterization of the scene.

  4. Visual and radiometric photometry of 1580 Betulia. [asteroid infrared observation

    NASA Technical Reports Server (NTRS)

    Lebofsky, L. A.; Veeder, G. J.; Matson, D. L.; Lebofsky, M. J.

    1978-01-01

    Broadband visual and 10.6-micron photometry of 1580 Betulia was obtained during its close approach to earth in May 1976. The photometry was analyzed by using the 'radiometric method' to derive the radius (2.10 + or - 0.40 km) and albedo (0.108 + or - 0.012) of Betulia. Radar and polarimetric results indicate a radius greater than 3.0 km and a geometric albedo of about 0.05. To be compatible with these results, Betulia was also modeled as having a surface with the thermal characteristics of bare rock rather than those of the 'lunar' regolith model used for previous analysis of radiometry of other asteroids. A 3.7-km radius and a geometric albedo of about 0.04 are compatible with all available observations. Betulia is the first Mars-crossing asteroid found to have such a low albedo, which may be indicative of carbonaceous surface material.

  5. Airborne Millimeter-Wave Radiometric Observations of Cirrus Clouds

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Racette, P.

    1997-01-01

    This paper reports the first radiometric measurements of cirrus clouds in the frequency range of 89-325 GHz from a high-altitude aircraft flight. The measurements are conducted with a Millimeter-wave Imaging Radiometer (MIR) on board the NASA ER-2 aircraft over a region in northern Oklahoma. Aboard the same aircraft are a cloud lidar system and a multichannel radiometer operating at the visible and infrared wavelengths. The instrument ensemble is well suited for identifying cirrus clouds. It is shown that the depressions in brightness temperatures associated with a few intense cirrus clouds occur at all frequency channels of the MIR. Estimates of total ice water path of the cirrus clouds are derived from comparisons of radiative transfer calculations and observed brightness depressions.

  6. Radiometric resolution for monitoring vegetation: How many bits are needed?

    NASA Technical Reports Server (NTRS)

    Tucker, C. J.

    1979-01-01

    The significance of the various number of radiometric quantizing levels required for satellite monitoring of vegetation resources was evaluated by using in situ collected spectral reflectance data, an atmospheric radiative transfer simulation model, and a satellite sensor simulation model. Reflectance data were converted to radiance data; passed through a model atmosphere to an altitude of 706 km; and subsequently quantized at 16, 32, 64, 128, 256, and 512 digital count levels for Thematic Mapper bands TM3(0.63 - 0.69 microns) and TM4(0.76 - 0.90 microns). The simulated digital count data were regressed against the in situ biological data to quantify the relationship between quantizing levels.

  7. The importance and attainment of accurate absolute radiometric calibration

    NASA Technical Reports Server (NTRS)

    Slater, P. N.

    1984-01-01

    The importance of accurate absolute radiometric calibration is discussed by reference to the needs of those wishing to validate or use models describing the interaction of electromagnetic radiation with the atmosphere and earth surface features. The in-flight calibration methods used for the Landsat Thematic Mapper (TM) and the Systeme Probatoire d'Observation de la Terre, Haute Resolution visible (SPOT/HRV) systems are described and their limitations discussed. The questionable stability of in-flight absolute calibration methods suggests the use of a radiative transfer program to predict the apparent radiance, at the entrance pupil of the sensor, of a ground site of measured reflectance imaged through a well characterized atmosphere. The uncertainties of such a method are discussed.

  8. [In-flight absolute radiometric calibration of UAV multispectral sensor].

    PubMed

    Chen, Wei; Yan, Lei; Gou, Zhi-Yang; Zhao, Hong-Ying; Liu, Da-Ping; Duan, Yi-Ni

    2012-12-01

    Based on the data of the scientific experiment in Urad Front Banner for UAV Remote Sensing Load Calibration Field project, with the help of 6 hyperspectral radiometric targets with good Lambertian property, the wide-view multispectral camera in UAV was calibrated adopting reflectance-based method. The result reveals that for green, red and infrared channel, whose images were successfully captured, the linear correlation coefficients between the DN and radiance are all larger than 99%. In final analysis, the comprehensive error is no more than 6%. The calibration results demonstrate that the hyperspectral targets equipped by the calibration field are well suitable for air-borne multispectral load in-flight calibration. The calibration result is reliable and could be used in the retrieval of geophysical parameters. PMID:23427528

  9. Radiometric Normalization On SAR Images For Oil Spill Detection

    NASA Astrophysics Data System (ADS)

    Singha, Suman; Topouzelis, Konstantinos; Vespe, Michele; Trieschmann, Olaf

    2013-12-01

    Oil spills on the European waters are observed relatively often. Pollution due accidental and deliberate oil spill from ships and rigs represents a serious threat to the marine and coastal environment. Operational oil spill monitoring such as CleanSeaNet' hosted by European Maritime Safety Agency (EMSA) is currently using SAR based maritime surveillance for oil spill and ship detection. A total of 2069 potential spills were reported by EMSA in 2012 reduced from 3311 reported spill in 2008. Primarily, conventional wide swath mode X- band (2.4-3.75 cm) and C-band (3.75-7.5 cm) SAR products have been used for operational purpose due to its large coverage and cost effectiveness. However this wide swath SAR images affected by reduced backscatter from near range to far range and normalization process on those images is highly desirable. Different approaches to radiometrically normalise SAR images are investigated and implemented.

  10. Summary of flight technology workshop on radiometric calibration

    NASA Technical Reports Server (NTRS)

    Dodgen, J. A.

    1980-01-01

    The conclusions and recommendations from a three-day NASA sponsored workshop to assess deficiencies and shortcomings of previously flown electro-optical space sensors are summarized. Space technologists for NASA, NOAA, DOD, and industry also developed recommendations for improving instrumentation and calibration technology. The conclusions reached include the fact that the past knowledge of in-orbit radiometric accuracy has been poor relative to available calibration standards, whereas stringent accuracy requirements for planned NASA programs will require significant SOA improvements. The Shuttle contamination environment may also compromise future sensor accuracy. A number of panel recommendations to improve in-orbit accuracy of future sensors will be summarized, including one to establish a set of National Standards for Remote Sensors at NBS as a basis for long term accuracy.

  11. Determination of precipitation profiles from airborne passive microwave radiometric measurements

    NASA Technical Reports Server (NTRS)

    Kummerow, Christian; Hakkarinen, Ida M.; Pierce, Harold F.; Weinman, James A.

    1991-01-01

    This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two case studies, a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometer density.

  12. JPSS-1 VIIRS pre-launch radiometric performance

    NASA Astrophysics Data System (ADS)

    Oudrari, Hassan; McIntire, Jeff; Xiong, Xiaoxiong; Butler, James; Efremova, Boryana; Ji, Qiang; Lee, Shihyan; Schwarting, Tom

    2015-09-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) on-board the first Joint Polar Satellite System (JPSS) completed its sensor level testing on December 2014. The JPSS-1 (J1) mission is scheduled to launch in December 2016, and will be very similar to the Suomi-National Polar-orbiting Partnership (SNPP) mission. VIIRS instrument was designed to provide measurements of the globe twice daily. It is a wide-swath (3,040 km) cross-track scanning radiometer with spatial resolutions of 370 and 740 m at nadir for imaging and moderate bands, respectively. It covers the wavelength spectrum from reflective to long-wave infrared through 22 spectral bands [0.412 μm to 12.01 μm]. VIIRS observations are used to generate 22 environmental data products (EDRs). This paper will briefly describe J1 VIIRS characterization and calibration performance and methodologies executed during the pre-launch testing phases by the independent government team, to generate the at-launch baseline radiometric performance, and the metrics needed to populate the sensor data record (SDR) Look-Up-Tables (LUTs). This paper will also provide an assessment of the sensor pre-launch radiometric performance, such as the sensor signal to noise ratios (SNRs), dynamic range, reflective and emissive bands calibration performance, polarization sensitivity, bands spectral performance, response-vs-scan (RVS), near field and stray light responses. A set of performance metrics generated during the pre-launch testing program will be compared to the SNPP VIIRS pre-launch performance.

  13. IRCM spectral signature measurements instrumentation featuring enhanced radiometric accuracy

    NASA Astrophysics Data System (ADS)

    Lantagne, Stéphane; Prel, Florent; Moreau, Louis; Roy, Claude; Willers, Cornelius J.

    2015-10-01

    Hyperspectral Infrared (IR) signature measurements are performed in military applications including aircraft- and -naval vessel stealth characterization, detection/lock-on ranges, and flares efficiency characterization. Numerous military applications require high precision measurement of infrared signature characterization. For instance, Infrared Countermeasure (IRCM) systems and Infrared Counter-Countermeasure (IRCCM) system are continuously evolving. Infrared flares defeated IR guided seekers, IR flares became defeated by intelligent IR guided seekers and Jammers defeated the intelligent IR guided seekers [7]. A precise knowledge of the target infrared signature phenomenology is crucial for the development and improvement of countermeasure and counter-countermeasure systems and so precise quantification of the infrared energy emitted from the targets requires accurate spectral signature measurements. Errors in infrared characterization measurements can lead to weakness in the safety of the countermeasure system and errors in the determination of detection/lock-on range of an aircraft. The infrared signatures are analyzed, modeled, and simulated to provide a good understanding of the signature phenomenology to improve the IRCM and IRCCM technologies efficiency [7,8,9]. There is a growing need for infrared spectral signature measurement technology in order to further improve and validate infrared-based models and simulations. The addition of imagery to Spectroradiometers is improving the measurement capability of complex targets and scenes because all elements in the scene can now be measured simultaneously. However, the limited dynamic range of the Focal Plane Array (FPA) sensors used in these instruments confines the ranges of measurable radiance intensities. This ultimately affects the radiometric accuracy of these complex signatures. We will describe and demonstrate how the ABB hyperspectral imaging spectroradiometer features enhanced the radiometric accuracy of spectral signature measurements of infrared military targets.

  14. Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

    SciTech Connect

    Kayzar, Theresa M.; Williams, Ross W.

    2015-09-26

    The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th-234U, 226Ra-238U, 231Pa-235U, and 227Ac-235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra-238U and 227Ac-235U chronometers and provide information about nuclide migration during uranium processing.

  15. Parallel algorithms of relative radiometric correction for images of TH-1 satellite

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Zhang, Tingtao; Cheng, Jiasheng; Yang, Tao

    2014-05-01

    The first generation of transitive stereo-metric satellites in China, TH-1 Satellite, is able to gain stereo images of three-line-array with resolution of 5 meters, multispectral images of 10 meters, and panchromatic high resolution images of 2 meters. The procedure between level 0 and level 1A of high resolution images is so called relative radiometric correction (RRC for short). The processing algorithm of high resolution images, with large volumes of data, is complicated and time consuming. In order to bring up the processing speed, people in industry commonly apply parallel processing techniques based on CPU or GPU. This article firstly introduces the whole process and each step of the algorithm - that is in application - of RRC for high resolution images in level 0; secondly, the theory and characteristics of MPI (Message Passing Interface) and OpenMP (Open Multi-Processing) parallel programming techniques is briefly described, as well as the superiority for parallel technique in image processing field; thirdly, aiming at each step of the algorithm in application and based on MPI+OpenMP hybrid paradigm, the parallelizability and the strategies of parallelism for three processing steps: Radiometric Correction, Splicing Pieces of TDICCD (Time Delay Integration Charge-Coupled Device) and Gray Level Adjustment among pieces of TDICCD are deeply discussed, and furthermore, deducts the theoretical acceleration rates of each step and the one of whole procedure, according to the processing styles and independence of calculation; for the step Splicing Pieces of TDICCD, two different strategies of parallelism are proposed, which are to be chosen with consideration of hardware capabilities; finally, series of experiments are carried out to verify the parallel algorithms by applying 2-meter panchromatic high resolution images of TH-1 Satellite, and the experimental results are analyzed. Strictly on the basis of former parallel algorithms, the programs in the experiments are written by parallelizing the serial version. Numerical results show that, the parallel algorithms proposed in this article can effectively bring up the processing speed of RRC for high resolution images of TH-1 Satellite, and, with its stable running and excellent image processing, meet the need of application. For three kinds of images, such as images with large amount of cloud, with little differences of ground features, and with good climate and plentiful ground features, the average acceleration rates could reach 2.484, 2.539 and 4.159 respectively.

  16. Effect of MODIS Terra Radiometric Calibration Improvements on Collection 6 Deep Blue Aerosol Products: Validation and Terra/Aqua Consistency

    NASA Technical Reports Server (NTRS)

    Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.; Jeong, M.-J.; Meister, G.

    2015-01-01

    The Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by approximately 0.04 over bright (e.g., desert) and approximately 0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by approximately 10% and approximately 5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.

  17. Concept, Simulation, and Instrumentation for Radiometric Inflight Icing Detection

    NASA Technical Reports Server (NTRS)

    Ryerson, Charles; Koenig, George G.; Reehorst, Andrew L.; Scott, Forrest R.

    2009-01-01

    The multi-agency Flight in Icing Remote Sensing Team (FIRST), a consortium of the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), the National Center for Atmospheric Research (NCAR), the National Oceanographic and Atmospheric Administration (NOAA), and the Army Corps of Engineers (USACE), has developed technologies for remotely detecting hazardous inflight icing conditions. The USACE Cold Regions Research and Engineering Laboratory (CRREL) assessed the potential of onboard passive microwave radiometers for remotely detecting icing conditions ahead of aircraft. The dual wavelength system differences the brightness temperature of Space and clouds, with greater differences potentially indicating closer and higher magnitude cloud liquid water content (LWC). The Air Force RADiative TRANsfer model (RADTRAN) was enhanced to assess the flight track sensing concept, and a 'flying' RADTRAN was developed to simulate a radiometer system flying through simulated clouds. Neural network techniques were developed to invert brightness temperatures and obtain integrated cloud liquid water. In addition, a dual wavelength Direct-Detection Polarimeter Radiometer (DDPR) system was built for detecting hazardous drizzle drops. This paper reviews technology development to date and addresses initial polarimeter performance.

  18. Ground-based radiometric measurements of slant-path attenuation in the V/W bands

    NASA Astrophysics Data System (ADS)

    Brost, George; Magde, Kevin

    2014-12-01

    Ground-based radiometric techniques were applied to measure the slant-path attenuation cumulative distribution function to over 20 dB of attenuation and to less than 1% exceedance probability at the V and W band frequencies of 72.5 and 82.5 GHz. These are the first such measurements in these frequency bands. Brightness temperature measurements were collected at an elevation angle of 36 in Rome, NY, using a four-channel radiometer that included 23.8 and 31.4 GHz receivers. A model-based approach was used to invert brightness temperature to attenuation. An atmospheric model relevant to the geographic location and statistically representative of the attenuating conditions was developed for this purpose. The main assumption of the atmospheric model was that the sources of attenuation for exceedance probabilities of concern were dominated by stratiform rain. Monte Carlo solutions to the radiative transfer equation for the precipitating atmosphere were used to generate the attenuation retrieval algorithm. Sensitivity analysis showed that the attenuation retrieval algorithm was robust to uncertainties in the model parameters. Slant-path attenuation was also measured with the radiometer using the Sun as a source of radiation. Over 30 dB of attenuation dynamic range was possible with this technique. Sun-beacon measurements were used to test model predictions.

  19. Radiometric Characterization of the IKONOS, QuickBird, and OrbView-3 Sensors

    NASA Technical Reports Server (NTRS)

    Holekamp, Kara

    2006-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can better understand their properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, satellite at-sensor radiance values were compared to those estimated by each independent team member to determine the sensor's radiometric accuracy. The combined results of this evaluation provide the user community with an independent assessment of these commercially available high spatial resolution sensors' absolute calibration values.

  20. Radiometric Calibration Assessment of Commercial High Spatial Resolution Multispectral Image Products

    NASA Technical Reports Server (NTRS)

    Holekamp, Kara; Aaron, David; Thome, Kurtis

    2006-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can better understand their properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, satellite at-sensor radiance values were compared to those estimated by each independent team member to determine the sensor's radiometric accuracy. The combined results of this evaluation provide the user community with an independent assessment of these commercially available high spatial resolution sensors' absolute calibration values.

  1. Radiometric sand mud characterisation in the Rhine-Meuse Estuary. Part B. In situ mapping

    NASA Astrophysics Data System (ADS)

    van Wijngaarden, M.; Venema, L. B.; De Meijer, R. J.

    2002-02-01

    Traditionally, obtaining accurate spatial information about the textural composition of heterogeneous aquatic sediments requires extensive sediment sampling. To avoid a costly and time-consuming operation, a new in situ technique has been investigated. This technique characterises sediment components by the activity concentrations of natural radionuclides. In situ activity concentrations are continuously measured with the Multi-Detector system for Underwater Sediment Activity (MEDUSA), a detector trailed over the bottom by a towing vessel, containing a highly sensitive gamma-ray BGO-detector, a water-depth sensor and a microphone. From the collected ?-ray spectra, the activity concentrations of 40K, 238U and 232Th are derived. During two separate field surveys of 5 days each, MEDUSA was applied to the Hollandsch Diep and Haringvliet, two fresh water basins, each approximately 20 km long and 2-3 km wide in the Rhine-Meuse Estuary, the Netherlands. In part A of this paper (this issue), it has been illustrated how the radiometric fingerprint of sand and mud in the area was determined. This fingerprint was then used to calculate the sand-mud ratio from the 238U and 232Th activity concentrations of about 25,000 MEDUSA data points. The interpolated sand-mud distribution of the top layer of the aquatic sediment shows a distinct correlation with bathymetry: the deeper channels are mud-rich, whereas the shallow zones are predominantly sandy. In general, the mud content decreases in the seaward direction. This corroborates well with the morphological development of the area in which the deposition of mud is highest near the rivers' outflow in the east. The absolute total random error in the sand map varies between 6% and 18%, where the largest errors are caused principally by spatial variability of the sediment composition. At present, the radiometric results underestimate the mud content by 10-30% due to a higher water content of sediment with high mud contents (>60%). The simultaneously recorded friction sound levels provide qualitative information with respect to the sediment composition. Sandy areas show a higher sound level than muddy areas; with the sound and sand map showing a striking similarity.

  2. Absolute Dating of Desert Varnish Using Portable X-Ray Fluorescence: Calibration and Testing

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Lytle, F. W.; Rowley, P. D.; Ferris, D. E.

    2004-12-01

    Desert varnish, also called rock varnish, is a thin biogenic layer of Mn-oxides, Fe-oxides, and clays that coats rock surfaces in arid and semi-arid regions. The mass of these metals in the varnish registers cumulative biologic activity over time and presents a possible dating mechanism, subject to appropriate assumptions and restrictions. We have used a portable x-ray fluorescence (PXRF) unit to measure Mn and Fe in numerous desert varnishes, both in the field and laboratory; the anticipated relationship between age and mass emerges from these data. Our attempts to refine the PXRF technique for absolute dating of desert varnish are confounded by the limited number of "dated" varnishes available to calibrate and test the method. Although there is no current method to directly ascertain the age of desert varnish, our search for "dated" varnishes has yielded three suitable types of test materials: (1) The ages of young basalt flows dated by various K/Ar radiometric techniques represent the maximum age of varnish developed on those surfaces. Such rocks are useful in the time range of perhaps 250,000 to 10,000 years; surface spalling with loss of varnish presents an upper time limit and difficulty in dating Holocene basalts presents a lower limit. Basalt flows typically provide horizontal surfaces that are ideal for PXRF measurements because, as a biogenic process, varnish development even at a single site varies with solar orientation. (2) Petroglyphs are the rock art that native peoples produced by pecking away varnish to expose fresh rock. This process restarts varnish development and the pecked surface gradually repatinates over time. At some locales, certain figures, symbols, and stylistic elements can be associated with an archaeological culture of known antiquity and duration, thus providing an age range for such glyphs. In the desert Southwest and Great Basin of the United States, appropriate glyphs are known from the present to at least 7000 years BP. Many of these petroglyphs are developed on vertical surfaces, which complicates dating both within and between sites. (3) The ages of the development of a number of geomorphic surfaces have been constrained by stratigraphic correlation and by dating of basalts, Pleistocene lake shorelines, and organic material. Such ages may in turn be associated with the initial exposure of fresh surfaces on cobbles and boulders on these geomorphic surfaces. We have compared the Mn and Fe accumulation in desert varnish from a variety of sites where the age of the fresh surface is constrained by one of the three approaches described above. Results thus far suggest that the current PXRF technique can provide absolute ages useful in situations where a significant uncertainty range is tolerable. Obvious sources of error in calibration and deployment of the PXRF technique that need to be addressed include errors in the dates of materials in the training sets, time lag between exposure of rock surface and varnish development, variations in surface orientation and micro-climate, and climate change over the course of varnish development.

  3. San Bernardino Cave (Italy) and the Appearance of Levallois Technology in Europe: Results of a Radiometric and Technological Reassessment

    PubMed Central

    Picin, Andrea; Peresani, Marco; Falgures, Christophe; Gruppioni, Giulia; Bahain, Jean-Jacques

    2013-01-01

    The introduction of Levallois technology in Europe marked the transition from the Lower to the early Middle Paleolithic. This new method of flake production was accompanied by significant behavioral changes in hominin populations. The emergence of this technological advance is considered homogeneous in the European archaeological record at the Marine isotopic stage (MIS) 9/MIS 8 boundary. In this paper we report a series of combined electron spin resonance/U-series dates on mammal bones and teeth recovered from the lower units of San Bernardino Cave (Italy) and the technological analyses of the lithic assemblages. The San Bernardino Cave has yielded the earliest evidence of Levallois production on the Italian Peninsula recovered to date. In addition to our results and the review of the archaeological record, we describe the chronological and geographical differences between European territories and diversities in terms of technological developments. The belated emergence of Levallois technology in Italy compared to western Europe corresponds to the late Italian Neanderthal speciation event. The new radiometric dates and the technological analyses of San Bernardino Cave raise the issue of the different roles of glacial refugia in the peopling and the spread of innovative flaking strategies in Europe during the late Middle Pleistocene. PMID:24146836

  4. South american geochronology: radiometric time scale for middle to late tertiary mammal-bearing horizons in patagonia.

    PubMed

    Marshall, L G; Pascual, R; Curtis, G H; Drake, R E

    1977-03-25

    Radiometric (potassium-argon) age determinations for basalts and tuffs associated with middle to late Tertiary mammal-bearing horizons in Patagonia, southern Argentina, permit refinement of boundaries and hiatuses between beds of Deseadan (early Oligocene) through Friasian (middle to late Miocene) age. At two localities beds of Deseadan age are overlain by basalts, which gave dates of 33.6 and 35.4 million years ago; 34.0 million years ago is tentatively accepted as a terminal date for known Deseadan. At several localities beds of Colhuehuapian age are underlain by basalts, which gave dates ranging from 28.8 to 24.3 million years ago; 25.0 million years is tentatively taken as a basal age for known Colhuehuapian. The paleontological hiatus between known Deseadan and known Colhuehuapian is thus in the order of 9.0 million years. Two tuffs from the Santa Cruz Formation (Santacrucian) gave ages of 21.7 and 18.5 million years. Plagioclase and biotite concentrates of an ignimbrite from the Colln Cur Formation (Friasian) gave ages ranging from 15.4 to 14.0 million years. PMID:17738414

  5. Dating the Crucifixion

    NASA Astrophysics Data System (ADS)

    Humphreys, Colin J.; Waddington, W. G.

    1983-12-01

    The date of the Crucifixion has been debated for many years, but there has been no agreement on the year nor the day. Astronomical calculations have now been used to reconstruct the Jewish calendar in the first century AD and to date a lunar eclipse that biblical and other references suggest followed the Crucifixion. The evidence points to Friday 3 April AD 33 as the date when Jesus Christ died.

  6. Dating of Impact Events

    NASA Astrophysics Data System (ADS)

    Schrer, U.

    Introduction Some Numbers amd Definitions Geological Dating Methods Crater Counting Bio-magnetostratigraphy and Paleomagnetism Nuclear Dating Methods General Aspects Thermoluminescence Cosmogenic Nuclides Fission Track Dating Radioactive Decay Shock Wave Metamorphism General Aspects Coherent Impacts Melt Layers The Crater Basement Allochthonous Breccia Deposits Distant Ejecta Implications from Experiments Dating and Sample Selection Geological Frame Coherent Impact Melt Layers Allochthonous Breccia Deposits Crater Basement Distant Ejecta Deposits Examples Impactites of the Crater Area Distant Ejecta, and the Cretaceous/Tertiary (K/T) Boundary Crater Basement References

  7. The Landsat Data Continuity Mission Operational Land Imager: Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Markham, Brian; Dabney, Philip; Pedelty, Jeffrey

    2011-01-01

    The Operational Land Imager (OLI) is one of two instruments to fly on the Landsat Data Continuity Mission (LDCM), which is scheduled to launch in December 2012 to become the 8th in the series of Landsat satellites. The OLI images in the solar reflective part of the spectrum, with bands similar to bands 1-5, 7 and the panchromatic band on the Landsat-7 ETM+ instrument. In addition, it has a 20 nm bandpass spectral band at 443 nm for coastal and aerosol studies and a 30 nm band at 1375 nm to aid in cirrus cloud detection. Like ETM+, spatial resolution is 30 m in the all but the panchromatic band, which is 15 meters. OLI is a pushbroom radiometer with approximately 6000 detectors per 30 meter band as opposed to the 16 detectors per band on the whiskbroom ETM+. Data are quantized to 12 bits on OLI as opposed to 8 bits on ETM+ to take advantage of the improved signal to noise ratio provided by the pushbroom design. The saturation radiances are higher on OLI than ETM+ to effectively eliminate saturation issues over bright Earth targets. OLI includes dual solar diffusers for on-orbit absolute and relative (detector to detector) radiometric calibration. Additionally, OLI has 3 sets of on-board lamps that illuminate the OLI focal plane through the full optical system, providing additional checks on the OLI's response[l]. OLI has been designed and built by Ball Aerospace & Technology Corp. (BATC) and is currently undergoing testing and calibration in preparation for delivery in Spring 2011. Final pre-launch performance results should be available in time for presentation at the conference. Preliminary results will be presented below. These results are based on the performance of the Engineering Development Unit (EDU) that was radiometrically tested at the integrated instrument level in 2010 and assembly level measurements made on the flight unit. Signal-to-Noise (SNR) performance: One of the advantages of a pushbroom system is the increased dwell time of the detectors allowing for significantly higher SNR than equivalent aperture whiskbroom systems. OLI performance based on the EDU at the "typical" radiance level as specified in the OLI requirements document are about 10 times better than ETM+ performance and 2-3 times better than the requirements for OLI (Table 1).

  8. Experimental Research on Passive Millimeter Wave Radiometric Stealth Technology of Metal Objects

    NASA Astrophysics Data System (ADS)

    Zhang, Guangfeng; Lou, Guowei; Li, Xingguo

    2012-12-01

    Working all day and all weather, a passive millimeter wave radiometer (PMMW) can be widely used in civil and military affairs. It can get some specific information about the material characteristics different from radar and infrared detectors. On basis of the radiometric operating range equation, the radiation cross section and stealth effect of metal objects are presented for the PMMW near-sensing application. The measurement experiments of metal solid models adopts 3 mm band Dicke radiometer with the outdoor calibration system. The sky temperature and other different surface metal objects are also measured as the contrastive experiments. The results show the radiometric temperature contrasts of solid models have remarkable difference in the bare and coated conditions, and the radiometric operating range can decrease to 60.8 %. In addition, the PMMW stealth methods through different surface treatment respectively reduce the radiometric antenna temperature contrast in some degree.

  9. Advanced radiometric complex for detection of radioactive release from Siberian chemical combine

    NASA Astrophysics Data System (ADS)

    Kolotkov, Gennady A.; Penin, Sergei T.

    2015-11-01

    The paper states limited availability of the use of the automated radiation situation monitoring system and proposes radiometric complex as more reliable system in the case of an accidental release of the Siberian Chemical Enterprises.

  10. Flight Technology Improvement. [spaceborne optical radiometric instruments, attitude control, and electromechanical and power subsystems

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Shortcomings in spaceborne instrumentation technology are analyzed and recommendations are given for corrections and technology development. The technologies discussed are optical radiometric instruments and calibration, attitude control and determination, and electromechanical and power subsystems.

  11. Radiometric order preserving method to display wide-dynamic images for imagery photointerpretation

    NASA Astrophysics Data System (ADS)

    Kattnig, Alain Philippe; Primot, Jrme

    2006-10-01

    Wide-dynamic numerical images are increasingly frequent in professional environments, military photointerpretation, and x-ray or magnetic resonance medical imagery. However, a dynamic compression process is necessary to exploit such images without incessant image manipulation. A wealth of efficient methods has been developed to tackle this problem on aesthetic grounds. We argue that professional imagery interpretation needs preservation of the original radiometric order. We develop a measure of image efficiency use of the 8-bit radiometric channel and find that it correlates nicely with subjective appraisal. The image underscores a radiometric order-preserving process to reach a standard radiometric efficiency. Lost information is then reintroduced by addition of an edge image devoid of artifacts, with an automatic weighting ensuring a natural-looking image.

  12. COMPARISON OF LAND SURFACE EMISSIVITY AND RADIOMETRIC TEMPERATURE DERIVED FROM MODIS AND ASTER SENSORS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compares surface emissivity and radiometric temperature products derived using data collected with the MODerate resolution Imaging Spectroradiometer (MODIS) and Advanced Spaceborne Thermal Emission Reflectance Radiometer (ASTER) sensors, on the Earth Observation System (EOS) - Terra satel...

  13. Intra-annual NDVI validation of the Landsat 5 TM radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Groeneveld, D.P.

    2009-01-01

    Multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone of the extensive archive of moderate-resolution Earth imagery. Even after more than 24 years of service, the L5 TM is still operational. Given the longevity of the satellite, the detectors have aged and the sensor's radiometric characteristics have changed since launch. The calibration procedures and parameters in the National Land Archive Production System (NLAPS) have also changed with time. Revised radiometric calibrations in 2003 and 2007 have improved the radiometric accuracy of recently processed data. This letter uses the Normalized Difference Vegetation Index (NDVI) as a metric to evaluate the radiometric calibration. The calibration change has improved absolute calibration accuracy, consistency over time, and consistency with Landsat 7 (L7) Enhanced Thematic radiometry and will provide the basis for continued long-term studies of the Earth's land surfaces.

  14. Dating Scripts Revisited.

    ERIC Educational Resources Information Center

    Laner, Mary Riege; Ventrone, Nicole A.

    2000-01-01

    Study used a method different from that of past studies to reexamine first-date scripts of heterosexual college students. As expected, the findings did not change. Despite egalitarian claims, initial dating practices consistently appear to be primarily traditional. Article concludes that semi-egalitarian, semi-traditional perspectives of students

  15. Date Palm Germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter reviews date palm genetic resources and their conservation. Date palm (Phoenix dactylifera) is an important food crop in the Middle East and North Africa. Its center of origin and diversity most probably is the area near Iraq/Iran. From there, it spread throughout its present range...

  16. Dating Violence in Russia

    ERIC Educational Resources Information Center

    Lysova, A. V.

    2007-01-01

    The phenomenon of violence in interpersonal relationships has been little studied in Russia, and the phenomenon of violence between dating partners has not been the object of scientific interest at all. The study on which the present article is based was designed to obtain information about the violence in dating among students enrolled in…

  17. Adolescent Date Selection.

    ERIC Educational Resources Information Center

    Dale, Julia A.

    Counselors, ministers, parents, and educators, need to know about adolescent date selection because it is normal for adolescents to seek assistance and affirmation from adults. An overview of the literature revealed that some of the factors influencing adolescent date selection were the developmental stage the adolescent is in, the expectations…

  18. Radiometric Accuracy Assessment of LANDSAT-4 Multispectral Scanner (MSS) Data. [Vermont

    NASA Technical Reports Server (NTRS)

    Alford, W. L.; Imhoff, M. L.

    1984-01-01

    The LANDSAT-4 mission has unique characteristics relative to previous LANDSAT missions. The spacecraft is new; the orbit is lower with a more frequent repeat cycle; and the ground processing facility consists of new hardware with different algorithms being applied. How some of these changes affect the character of the radiometric data quality is explored. Banding effects; radiometric differences between LANDSAT 3 and 4; and the woodgrain pattern observed visually in the images are considered.

  19. Study of Spectral/Radiometric Characteristics of the Thematic Mapper for Land Use Applications

    NASA Technical Reports Server (NTRS)

    Malila, W. A. (Principal Investigator); Metzler, M. D. (Principal Investigator)

    1985-01-01

    An investigation conducted in support of the LANDSAT 4/5 Image Data Quality Analysis (LIDQA) Program is discussed. Results of engineering analyses of radiometric, spatial, spectral, and geometric properties of the Thematic Mapper systems are summarized; major emphasis is placed on the radiometric analysis. Details of the analyses are presented in appendices, which contain three of the eight technical papers produced during this investigation; these three, together, describe the major activities and results of the investigation.

  20. Radiometric and signal-to-noise ratio properties of multiplex dispersive spectrometry.

    PubMed

    Barducci, Alessandro; Guzzi, Donatella; Lastri, Cinzia; Nardino, Vanni; Marcoionni, Paolo; Pippi, Ivan

    2010-10-01

    Recent theoretical investigations have shown important radiometric disadvantages of interferential multiplexing in Fourier transform spectrometry that apparently can be applied even to coded aperture spectrometers. We have reexamined the methods of noninterferential multiplexing in order to assess their signal-to-noise ratio (SNR) performance, relying on a theoretical modeling of the multiplexed signals. We are able to show that quite similar SNR and radiometric disadvantages affect multiplex dispersive spectrometry. The effect of noise on spectral estimations is discussed. PMID:20885473

  1. Radiometric and signal-to-noise ratio properties of multiplex dispersive spectrometry

    SciTech Connect

    Barducci, Alessandro; Guzzi, Donatella; Lastri, Cinzia; Nardino, Vanni; Marcoionni, Paolo; Pippi, Ivan

    2010-10-01

    Recent theoretical investigations have shown important radiometric disadvantages of interferential multiplexing in Fourier transform spectrometry that apparently can be applied even to coded aperture spectrometers. We have reexamined the methods of noninterferential multiplexing in order to assess their signal-to-noise ratio (SNR) performance, relying on a theoretical modeling of the multiplexed signals. We are able to show that quite similar SNR and radiometric disadvantages affect multiplex dispersive spectrometry. The effect of noise on spectral estimations is discussed.

  2. Radiometric STFT Analysis of PDV recordings and detectivity limit

    NASA Astrophysics Data System (ADS)

    Bozier, Olivier; Prudhomme, Gabriel; Mercier, Patrick; Berthe, Laurent

    2015-06-01

    Photonic Doppler Velocimetry is a plug-and-play and versatile diagnostic used in dynamic physic experiments to measure velocities. When signals are analyzed using a Short-Time Fourier Transform, multiple velocities can be distinguished: by example, the velocities of moving particle-cloud appear on spectrograms. In order to estimate the back-scattering fluxes of target, we propose an original approach ``PDV Radiometric analysis'' resulting in an expression of time-velocity spectrograms coded in power units. Experiments involving micron-sized particles raise the issue of detection limit; particle-size limit is very difficult to evaluate. From the quantification of noise sources, we derivate an estimation of the spectrogram noise leading to a detectivity limit. It may be compared to back-scattering and collected power from a particle, which is increasing with its size. At least, some results from laser-shock accelerated particles using two different PDV systems are compared: it may show the improvement of sensitivity.

  3. Robust Multiscale Stereo Matching from Fundus Images with Radiometric Differences

    PubMed Central

    Tang, Li; Garvin, Mona K.; Lee, Kyungmoo; Alward, Wallace L.M.; Kwon, Young H.; Abrmoff, Michael D.

    2013-01-01

    A robust multiscale stereo matching algorithm is proposed to find reliable correspondences between low contrast and weakly textured retinal image pairs with radiometric differences. Existing algorithms designed to deal with piecewise planar surfaces with distinct features and Lambertian reflectance do not apply in applications such as 3D reconstruction of medical images including stereo retinal images. In this paper, robust pixel feature vectors are formulated to extract discriminative features in the presence of noise in scale space, through which the response of low-frequency mechanisms alter and interact with the response of high-frequency mechanisms. The deep structures of the scene are represented with the evolution of disparity estimates in scale space, which distributes the matching ambiguity along the scale dimension to obtain globally coherent reconstructions. The performance is verified both qualitatively by face validity and quantitatively on our collection of stereo fundus image sets with ground truth, which have been made publicly available as an extension of standard test images for performance evaluation. PMID:21464502

  4. Radiometric oil well assay for glucokinase in microscopic structures

    SciTech Connect

    Bedoya, F.J.; Meglasson, M.D.; Wilson, J.M.; Matschinsky, F.M.

    1985-02-01

    Glucokinase plays a pivotal role in hepatic glucose metabolism and serves as the glucose sensor in pancreatic islet beta-cells. Biochemical studies of this enzyme are complicated by the cellular heterogeneity of the liver and the pancreas and because the presence of hexokinases seriously interferes with currently available analytical procedures. A radiometric assay was designed to deal with these problems. It is based on the liberation of /sup 3/H/sub 2/O from D-(2-/sup 3/H(N))glucose 6-phosphate, the product of the glucokinase reaction, using exogenous phosphoglucose isomerase. Interference by hexokinases was largely eliminated by using glucose 6-phosphate as inhibitor and the sensitivity of the assay was greatly increased by using small volumes with the oil well procedure. The assay was sufficiently sensitive to detect about 1 pg of glucokinase. It thus allowed the application of quantitative histochemical procedures to the study of intralobular hepatic glucokinase profiles and the pancreatic beta-cell glucose sensor. The quantitative histochemical procedures were sufficiently sensitive and reliable for measuring important kinetic constants of glucokinase in microscopic samples of tissue.

  5. Advanced radiometric and interferometric milimeter-wave scene simulations

    NASA Technical Reports Server (NTRS)

    Hauss, B. I.; Moffa, P. J.; Steele, W. G.; Agravante, H.; Davidheiser, R.; Samec, T.; Young, S. K.

    1993-01-01

    Smart munitions and weapons utilize various imaging sensors (including passive IR, active and passive millimeter-wave, and visible wavebands) to detect/identify targets at short standoff ranges and in varied terrain backgrounds. In order to design and evaluate these sensors under a variety of conditions, a high-fidelity scene simulation capability is necessary. Such a capability for passive millimeter-wave scene simulation exists at TRW. TRW's Advanced Radiometric Millimeter-Wave Scene Simulation (ARMSS) code is a rigorous, benchmarked, end-to-end passive millimeter-wave scene simulation code for interpreting millimeter-wave data, establishing scene signatures and evaluating sensor performance. In passive millimeter-wave imaging, resolution is limited due to wavelength and aperture size. Where high resolution is required, the utility of passive millimeter-wave imaging is confined to short ranges. Recent developments in interferometry have made possible high resolution applications on military platforms. Interferometry or synthetic aperture radiometry allows the creation of a high resolution image with a sparsely filled aperture. Borrowing from research work in radio astronomy, we have developed and tested at TRW scene reconstruction algorithms that allow the recovery of the scene from a relatively small number of spatial frequency components. In this paper, the TRW modeling capability is described and numerical results are presented.

  6. Design, manufacture, and calibration of infrared radiometric blackbody sources

    SciTech Connect

    Byrd, D.A.; Michaud, F.D.; Bender, S.C.

    1996-04-01

    A Radiometric Calibration Station (RCS) is being assembled at the Los Alamos National Laboratories (LANL) which will allow for calibration of sensors with detector arrays having spectral capability from about 0.4-15 {mu}m. The configuration of the LANL RCS. Two blackbody sources have been designed to cover the spectral range from about 3-15 {mu}m, operating at temperatures ranging from about 180-350 K within a vacuum environment. The sources are designed to present a uniform spectral radiance over a large area to the sensor unit under test. The thermal uniformity requirement of the blackbody cavities has been one of the key factors of the design, requiring less than 50 mK variation over the entire blackbody surface to attain effective emissivity values of about 0.999. Once the two units are built and verified to the level of about 100 mK at LANL, they will be sent to the National Institute of Standards and Technology (NIST), where at least a factor of two improvement will be calibrated into the blackbody control system. The physical size of these assemblies will require modifications of the existing NIST Low Background Infrared (LBIR) Facility. LANL has constructed a bolt-on addition to the LBIR facility that will allow calibration of our large aperture sources. Methodology for attaining the two blackbody sources at calibrated levels of performance equivalent to present state of the art will be explained in the following.

  7. Combined Geometric/radiometric Point Cloud Matching for Shear Analysis

    NASA Astrophysics Data System (ADS)

    Gehrke, S.

    2012-07-01

    In the recent past, dense image matching methods such as Semi-Global Matching (SGM) became popular for many applications. The SGM approach has been adapted to and implemented for Leica ADS line-scanner data by North West Geomatics (North West) in co-operation with Leica Geosystems; it is used in North West's production workflow. One of the advantages of ADS imagery is the calibrated color information (RGB and near infrared), extending SGM-derived point clouds to dense "image point clouds" or, more general, information clouds (info clouds). With the goal of automating the quality control of ADS data, info clouds are utilized for Shear Analysis: Three-dimensional offsets of adjacent ADS image strips are determined from a pattern of info cloud pairs in strip overlaps by point cloud matching. The presented approach integrates geometry (height) and radiometry (intensity) information; matching is based on local point-to-plane distances for all points in a given cloud. The offset is derived in a least squares adjustment by applying it to each individual distance computation equation. Using intensities in addition to heights greatly benefits the offset computation, because intensity gradients tend to occur more frequently than height gradients. They can provide or complement the required information for the derivation of planimetric offset components. The paper details the combined geometric/radiometric point cloud matching approach and verifies the results against manual measurements.

  8. Radiometric sensitivity contrast metrics for hyperspectral remote sensors

    NASA Astrophysics Data System (ADS)

    Silny, John F.; Zellinger, Lou

    2014-09-01

    This paper discusses the calculation, interpretation, and implications of various radiometric sensitivity metrics for Earth-observing hyperspectral imaging (HSI) sensors. The most commonly used sensor performance metric is signal-to-noise ratio (SNR), from which additional noise equivalent quantities can be computed, including: noise equivalent spectral radiance (NESR), noise equivalent delta reflectance (NEΔρ), noise equivalent delta emittance (NEΔƐ), and noise equivalent delta temperature (NEΔT). For hyperspectral sensors, these metrics are typically calculated from an at-aperture radiance (typically generated by MODTRAN) that includes both target radiance and non-target (atmosphere and background) radiance. Unfortunately, these calculations treat the entire at-aperture radiance as the desired signal, even when the target radiance is only a fraction of the total (such as when sensing through a long or optically dense atmospheric path). To overcome this limitation, an augmented set of metrics based on contrast signal-to-noise ratio (CNSR) is developed, including their noise equivalent counterparts (CNESR, CNEΔρ, CNEΔƐ, and CNEΔT). These contrast metrics better quantify sensor performance in an operational environment that includes remote sensing through the atmosphere.

  9. Radiometric analyses of Landsat-4 digital image data

    NASA Technical Reports Server (NTRS)

    Malila, W. A.; Rice, D. P.; Metzler, M. D.

    1984-01-01

    The results of analyses of the radiometric characteristics of digital image data produced by the Landsat 4 MSS and TM sensors are reviewed. The MSS analysis found high quality data comparable to the products of previous Landsats, except for a low-level coherent noise effect having a magnitude of about 0.5 counts in each band and a spatial period of about 3.6 pixels. The TM analysis found excellent spatial resolution, generally high data quality and expected scan-angle effects. Procedures for equalizing detector responses appear to be working as intended. Two low-amplitude artifacts also were discovered. The first is associated with the direction of scan (TM employs bidirectional scanning). The second, a very low employs bidirectional scanning). The second, a very low frequency level-shift artifact which produces image banding that is most pronounced in TM1, could be a serious problem for water-related applications or others where average signal levels are low. Correction procedures are under investigation.

  10. Robust multiscale stereo matching from fundus images with radiometric differences.

    PubMed

    Tang, Li; Garvin, Mona K; Lee, Kyungmoo; Alward, Wallace L M; Kwon, Young H; Abrmoff, Michael D

    2011-11-01

    A robust multiscale stereo matching algorithm is proposed to find reliable correspondences between low contrast and weakly textured retinal image pairs with radiometric differences. Existing algorithms designed to deal with piecewise planar surfaces with distinct features and Lambertian reflectance do not apply in applications such as 3D reconstruction of medical images including stereo retinal images. In this paper, robust pixel feature vectors are formulated to extract discriminative features in the presence of noise in scale space, through which the response of low-frequency mechanisms alter and interact with the response of high-frequency mechanisms. The deep structures of the scene are represented with the evolution of disparity estimates in scale space, which distributes the matching ambiguity along the scale dimension to obtain globally coherent reconstructions. The performance is verified both qualitatively by face validity and quantitatively on our collection of stereo fundus image sets with ground truth, which have been made publicly available as an extension of standard test images for performance evaluation. PMID:21464502

  11. Evaluating AIRS Radiometric Error in Non-uniform Scenes using MODIS

    NASA Astrophysics Data System (ADS)

    Pagano, T. S.; Aumann, H. H.

    2014-12-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in 2378 channels ranging in wavelength from 3.7-15.4 um with spectral resolution of better than 1200, and spatial resolution of 13.5 km with global daily coverage. The AIRS was designed to measure temperature and water vapor profiles for improvement in weather forecast and improved parameterization of climate processes. Currently the AIRS Level 1B Radiance Products are assimilated by NWP centers worldwide and have shown considerable forecast improvement. AIRS L1 and L2 products are widely used for studying critical climate processes related to water vapor feedback, atmospheric transport and cloud properties. AIRS trace gas products include ozone profiles, carbon monoxide, and the first global maps of mid-tropospheric carbon dioxide. The AIRS radiances are calibrated using a uniform on-board blackbody and full aperture space view. For this reason, all radiometric measurements assume a uniform scene. As with most instruments, the AIRS 2D spatial response functions (tophat functions) are not flat for all channels, nor are they the same. When viewing a non-uniform scene, this causes a radiometric error that is scene dependent and cannot be removed without knowledge of the scene response. The magnitude of the error depends on the non-uniformity of the AIRS spatial response and the non-uniformity of the scene, but typically only affects about 1% of the data. In this effort we use data from the MODIS instrument to provide information on the scene uniformity that can be used to correct the AIRS data. Early results show we can match the AIRS and MODIS radiances to about 0.6K when we include the AIRS tophat functions in the normalization of the MODIS data (Elliott, Proc SPIE 6296, 2006). The method requires use of different infrared bands in MODIS depending on the channels of AIRS being corrected. Resulting improvement in noise and bias will be presented by comparing to the new AIRS Level 1C product that uses PC techniques to correct impacted channels. The method can be used to recover impacted channels, validate the Level 1C product, and identify scene conditions where the error is most significant.

  12. A multi-channel radiometric profiler of temperature, humidity and cloud liquid.

    SciTech Connect

    Ware, R.; Carpenter, R.; Guldner, J.; Liljegren, J.; Nehrkorn, T.; Solheim, F.; Vandenberghe, F.; Environmental Research; Radiometrics Corp.; Univ. Corp. for Atmospheric Research; Weather Decision Technologies Inc.; Atmospheric and Environmental Research Inc.; National Center for Atmospheric Research

    2003-07-31

    A microwave radiometer is described that provides continuous thermodynamic (temperature, water vapor, and moisture) soundings during clear and cloudy conditions. The radiometric profiler observes radiation intensity at 12 microwave frequencies, along with zenith infrared and surface meteorological measurements. Historical radiosonde and neural network or regression methods are used for profile retrieval. We compare radiometric, radiosonde, and forecast soundings and evaluate the accuracy of radiometric temperature and water vapor soundings on the basis of statistical comparison with radiosonde soundings. We find that radiometric soundings are equivalent in accuracy to radiosonde soundings when used in numerical weather forecasting. A case study is described that demonstrates improved fog forecasting on the basis of variational assimilation of radiometric soundings. The accuracy of radiometric cloud liquid soundings is evaluated by comparison with cloud liquid sensors carried by radiosondes. Accurate high-resolution three-dimensional water vapor and wind analysis is described on the basis of assimilation of simulated thermodynamic and wind soundings along with GPS slant delays. Examples of mobile thermodynamic and wind profilers are shown. Thermodynamic profiling, particularly when combined with wind profiling and slant GPS, provides continuous atmospheric soundings for improved weather and dispersion forecasting.

  13. Measurement of human placental 5'-AMP deaminase activity by radiometric assay

    SciTech Connect

    Maguire, M.H.; Aronson, D.M.

    1981-09-01

    The level of 5'-AMP deaminase in homogenates of human term placenta has been measured by means of a simple radiometric assay. The assay uses /sup 14/C-labeled AMP as substrate and incorporates conditions of pH and K/sup +/ concentration, which optimize the 5'-AMP deaminase activity, and inhibitors of 5'-nucleotidase and adenosine deaminase to reduce interferences from these enzymes. Assay products are separated by descending paper chromatography and quantitated by liquid scintillation counting. The activity of 5'-AMP deaminase in human term placenta determined by this assay was 474 +/- 37 nmol min/sup -1/ g/sup -1/ at 30/sup o/C and was less than the 5'-AMP phosphatase activity evident under the same assay conditions. The assay is suitable for measurement of 5'-AMP deaminase in extracts of other tissues in which high levels of phosphates and adenosine deaminase preclude assay of 5'-AMP deaminase by such techniques as ultraviolet absorption changes or ammonia estimation.

  14. Application of gamma-ray spectrometry in a NORM industry for its radiometrical characterization

    NASA Astrophysics Data System (ADS)

    Mantero, J.; Gázquez, M. J.; Hurtado, S.; Bolívar, J. P.; García-Tenorio, R.

    2015-11-01

    Industrial activities involving Naturally Occurring Radioactive Materials (NORM) are found among the most important industrial sectors worldwide as oil/gas facilities, metal production, phosphate Industry, zircon treatment, etc. being really significant the radioactive characterization of the materials involved in their production processes in order to assess the potential radiological risk for workers or natural environment. High resolution gamma spectrometry is a versatile non-destructive radiometric technique that makes simultaneous determination of several radionuclides possible with little sample preparation. However NORM samples cover a wide variety of densities and composition, as opposed to the standards used in gamma efficiency calibration, which are either water-based solutions or standard/reference sources of similar composition. For that reason self-absorption correction effects (especially in the low energy range) must be considered individually in every sample. In this work an experimental and a semi-empirical methodology of self-absorption correction were applied to NORM samples, and the obtained results compared critically, in order to establish the best practice in relation to the circumstances of an individual laboratory. This methodology was applied in samples coming from a TiO2 factory (NORM industry) located in the south-west of Spain where activity concentration of several radionuclides from the Uranium and Thorium series through the production process was measured. These results will be shown in this work.

  15. In-flight radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

    NASA Technical Reports Server (NTRS)

    Conel, James E.; Green, Robert O.; Alley, Ronald E.; Bruegge, Carol J.; Carrere, Veronique; Margolis, Jack S.; Vane, Gregg; Chrien, Thomas G.; Slater, Philip N.; Biggard, Stuart F.

    1988-01-01

    A reflectance-based method was used to provide an analysis of the in-flight radiometric performance of AVIRIS. Field spectral reflectance measurements of the surface and extinction measurements of the atmosphere using solar radiation were used as input to atmospheric radiative transfer calculations. Five separate codes were used in the analysis. Four include multiple scattering, and the computed radiances from these for flight conditions were in good agreement. Code-generated radiances were compared with AVIRIS-predicted radiances based on two laboratory calibrations (pre- and post-season of flight) for a uniform highly reflecting natural dry lake target. For one spectrometer (C), the pre- and post-season calibration factors were found to give identical results, and to be in agreement with the atmospheric models that include multiple scattering. This positive result validates the field and laboratory calibration technique. Results for the other spectrometers (A, B and D) were widely at variance with the models no matter which calibration factors were used. Potential causes of these discrepancies are discussed.

  16. Radiometric analysis of the longwave infrared channel of the Thematic Mapper on LANDSAT 4 and 5

    NASA Technical Reports Server (NTRS)

    Schott, John R.; Volchok, William J.; Biegel, Joseph D.

    1986-01-01

    The first objective was to evaluate the postlaunch radiometric calibration of the LANDSAT Thematic Mapper (TM) band 6 data. The second objective was to determine to what extent surface temperatures could be computed from the TM and 6 data using atmospheric propagation models. To accomplish this, ground truth data were compared to a single TM-4 band 6 data set. This comparison indicated satisfactory agreement over a narrow temperature range. The atmospheric propagation model (modified LOWTRAN 5A) was used to predict surface temperature values based on the radiance at the spacecraft. The aircraft data were calibrated using a multi-altitude profile calibration technique which had been extensively tested in previous studies. This aircraft calibration permitted measurement of surface temperatures based on the radiance reaching the aircraft. When these temperature values are evaluated, an error in the satellite's ability to predict surface temperatures can be estimated. This study indicated that by carefully accounting for various sensor calibration and atmospheric propagation effects, and expected error (1 standard deviation) in surface temperature would be 0.9 K. This assumes no error in surface emissivity and no sampling error due to target location. These results indicate that the satellite calibration is within nominal limits to within this study's ability to measure error.

  17. Utility of Assimilating Surface Radiometric Temperature Observations for Evaporative Fraction and Heat Transfer Coefficient Retrieval

    NASA Astrophysics Data System (ADS)

    Crow, Wade T.; Kustas, William P.

    2005-04-01

    Recent advances in land data assimilation have yielded variational smoother techniques designed to solve the surface energy balance based on remote observations of surface radiometric temperature. These approaches have a number of potential advantages over existing diagnostic models, including the ability to make energy flux predictions between observation times and reduced requirements for ancillary parameter estimation. Here, the performance of a recently developed variational smoother approach is examined in detail over a range of vegetative and hydrological conditions in the southern U.S.A. during the middle part of the growing season. Smoother results are compared with flux tower observations and energy balance predictions obtained from the two-source energy balance model (TSM). The variational approach demonstrates promise for flux retrievals at dry and lightly vegetated sites. However, results suggest that the simultaneous retrieval of both evaporative fraction and turbulent transfer coefficients by the variational approach will be difficult for wet and/or heavily vegetated land surfaces. Additional land surface information (e.g. leaf area index ( L AI) or the rough specification of evaporative fraction bounds) will be required to ensure robust predictions under such conditions. The single-source nature of the variational approach also hampers the physical interpretation of turbulent transfer coefficient retrievals. Intercomparisons between energy flux predictions from the variational approach and the purely diagnostic TSM demonstrate that the relative accuracy of each approach is contingent on surface conditions and the accuracy with which L AI values required by the TSM can be estimated.

  18. Polarization impacts on the water-leaving radiance retrieval from above-water radiometric measurements.

    PubMed

    Harmel, Tristan; Gilerson, Alexander; Tonizzo, Alberto; Chowdhary, Jacek; Weidemann, Alan; Arnone, Robert; Ahmed, Sam

    2012-12-10

    Above-water measurements of water-leaving radiance are widely used for water-quality monitoring and ocean-color satellite data validation. Reflected skylight in above-water radiometry needs to be accurately estimated prior to derivation of water-leaving radiance. Up-to-date methods to estimate reflection of diffuse skylight on rough sea surfaces are based on radiative transfer simulations and sky radiance measurements. But these methods neglect the polarization state of the incident skylight, which is generally highly polarized. In this paper, the effects of polarization on the sea surface reflectance and the subsequent water-leaving radiance estimation are investigated. We show that knowledge of the polarization field of the diffuse skylight significantly improves above-water radiometry estimates, in particular in the blue part of the spectrum where the reflected skylight is dominant. A newly developed algorithm based on radiative transfer simulations including polarization is described. Its application to the standard Aerosol Robotic Network-Ocean Color and hyperspectral radiometric measurements of the 1.5-year dataset acquired at the Long Island Sound site demonstrates the noticeable importance of considering polarization for water-leaving radiance estimation. In particular it is shown, based on time series of collocated data acquired in coastal waters, that the azimuth range of measurements leading to good-quality data is significantly increased, and that these estimates are improved by more than 12% at 413 nm. Full consideration of polarization effects is expected to significantly improve the quality of the field data utilized for satellite data validation or potential vicarious calibration purposes. PMID:23262527

  19. Early radiometric performance assessment of the Landsat-8 Operational Land Imager (OLI)

    NASA Astrophysics Data System (ADS)

    Barsi, Julia A.; Markham, Brian L.

    2013-09-01

    Landsat-8, the latest in the Landsat series of satellites, was launched on February 11, 2013 and carries on board the Operational Land Imager (OLI) as one of its payloads. The satellite's mission is to continue the long history of moderate resolution imaging of the Landsat program. The OLI follows the highly successful Landsat-5 and Landsat-7 in continuing to populate a global archive of Earth images that dates back to 1972. The design of the Landsat-8 instruments is a significant departure from earlier Landsats. The OLI is a pushbroom instrument; all previous recent Landsat instruments were electromechanical (whiskbroom) instruments. OLI also has two new spectral bands and refined bandpasses; the thermal imaging capability on Landsat-8 is in a separate instrument. The pushbroom design provides significantly better signal to noise performance than historically available, but at the expense of circa 70,000 detectors versus the 100 or so on previous instruments. The large focal plane and large number of detectors makes detector to detector relative calibration more challenging, increasing the propensity for banding and striping in imagery. On-board radiometric calibration devices include a shutter to measure the dark levels, a full aperture solar panel for calibration against the sun, and multiple sets of lamps for short-term stability monitoring. Early results from the on-board calibration devices indicate that the OLI is outperforming the Landsat-7 instrument in signal-to-noise ratio by an order of magnitude, consistent with pre-launch measurements. Over the first five months, the instrument is stable to within 0.7%, as measured by the lamps and solar diffuser. A relative calibration (detector-to-detector) and a linearization parameter update have been performed that reduce visible striping; with this update, the residual striping has been reduced by half in all OLI bands.

  20. On-orbit performance of the Landsat-7 ETM+ radiometric calibrators

    USGS Publications Warehouse

    Markham, Brian L; Barker, J. L.; Kaita, E.; Seiferth, J.; Morfitt, Ron

    2003-01-01

    The Landsat-7 Enhanced Thematic Mapper Plus (ETM+) incorporates two new devices to improve its absolute radiometric calibration: a Full Aperture Solar Calibrator (FASC) and a Partial Aperture Solar Calibrator (PASC). The FASC is a diffuser panel, typically deployed once per month. Initial FASC absolute calibration results were within 5% of the pre-launch calibrations. Over time, the responses of the ETM+ to the FASC have varied with the location viewed on the panel, suggesting a localized degradation or contamination of the panel. On the best part of the panel, the trends in response range from m 1.4% y m 1 (band 4) to +0.6% y m 1 (band 7), with band 5 showing the least change at m 0.4% y m 1 . Changes in the panel reflectance due to UV exposure are believed to be the origin of these trends. The PASC is a set of auxiliary optics that allows the ETM+ to image the Sun through reduced apertures. PASC data have normally been acquired on a daily basis. Unlike the FASC, the PASC has exhibited significant anomalies. During the first six months of operation, responses to the PASC increased up to 60%, sending bands 2, 3 and 8 into saturation (band 1 was saturated at launch). The short-wave infrared (SWIR) band individual detectors have shown variations up to - 20% in response to the PASC. The variation is different for each detector. After the first six months, the responses to the PASC have become more stable, with much of the variation related to the within-scan position of the solar image. Overall results to date for all calibrators and comparisons with vicarious calibrations indicate that most of the response variations have been due to the calibrators themselves and suggest that the instrument has been stable with changes in response of less than 0.5% y m 1 .

  1. Critical Evaluation of Radiometric Ages Used for Tracking Hotspots in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Baksi, A. K.

    2004-12-01

    One of the pillars supporting the plume hypothesis, is the progression of ages for numerous hotspot tracks in oceans. These ages should be based on radiometric measurements. The argon dating methods have been the tool most commonly used. Since most of the rocks selected for dating have suffered (considerable) alteration, K-Ar dates should not be used as accurate measures of the age of crystallization. 40Ar/39Ar total fusion ages, though better than K-Ar dates in general, do not pinpoint samples that (a) contain excess argon or (b) have suffered partial loss of 40Ar* due to alteration. Hence 40Ar/39Ar incremental heating studies remain as the (only) tool of choice. From such experiments, at a minimum, ages must be based on plateau and/or isochron sections that meet the necessary statistical requirements to be considered crystallization ages. Earlier (Baksi, 1999, Jour. Geol.) it has been shown that almost all the purported crystallization ages for hotspot tracks in the Atlantic and Indian Oceans, are invalid (see also www.mantleplumes.org/ArAr.html). Herein, I apply the tests outlined therein, to evaluate ages available in the literature for hotspot tracks in the Pacific Ocean. These can be divided into five main groups. (1) Those with reliable age data (e.g. Dalrymple and Garcia,1980; Dalrymple et al., 1980, DSDP 55, Hawaiian-Emperor Chain); the authors use care in selecting valid ages from their data sets. (2) Others (e.g. Pringle, 1993, AGU Monograph 77, Musicians Seamounts), most ages are statistically valid, though some fail the requisite test. In addition, many samples show high levels of atmospheric argon, suggesting the samples are (quite) altered; this could lead to incorrect plateau ages. (3) The next set (e.g. Winterer et al., 1993, AGU Monograph 77, Cretaceous guyots in the Northwest Pacific; Ozima et al., 1977, JGRAS, Western Pacific guyots; Saito and Ozima, 1977, EPSL, Western Pacific area) have few, if any, valid ages. Most plateaux/isochrons clearly fail the statistical test of reliability; many steps show high levels of atmospheric argon - the samples are (badly) altered. (4) A set of papers (e.g. Gripp and Gordon, 2002, Geophys. J. Int., young hotspot tracks; Duncan, 1985 - New Hebrides-Samoa lineament) make use of K-Ar dates, wholly or in the main. These dates should be treated as minimum estimates of the crystallization age. (5) A final set of papers (Sager et al., 1993, AGU Monograph 77, Japanese and Marcus-Wake Seamounts; Lincoln et al., 1993, AGU Monograph 77, Marshall Islands), quote ages without listing the relevant analytical data. These results are to be treated as suspect, and not used for quantitative tracking of hotspot trails. In conclusion, the purported progression of ages for numerous hotspot tracks in the Pacific Ocean does not withstand critical scrutiny.

  2. Mars chronology: Assessing techniques for quantifying surficial processes

    USGS Publications Warehouse

    Doran, P.T.; Clifford, S.M.; Forman, S.L.; Nyquist, L.; Papanastassiou, D.A.; Stewart, B.W.; Sturchio, N.C.; Swindle, T.D.; Cerling, T.; Kargel, J.; McDonald, G.; Nishiizumi, K.; Poreda, R.; Rice, J.W.; Tanaka, K.

    2004-01-01

    Currently, the absolute chronology of Martian rocks, deposits and events is based mainly on crater counting and remains highly imprecise with epoch boundary uncertainties in excess of 2 billion years. Answers to key questions concerning the comparative origin and evolution of Mars and Earth will not be forthcoming without a rigid Martian chronology, enabling the construction of a time scale comparable to Earth's. Priorities for exploration include calibration of the cratering rate, dating major volcanic and fluvial events and establishing chronology of the polar layered deposits. If extinct and/or extant life is discovered, the chronology of the biosphere will be of paramount importance. Many radiometric and cosmogenic techniques applicable on Earth and the Moon will apply to Mars after certain baselines (e.g. composition of the atmosphere, trace species, chemical and physical characteristics of Martian dust) are established. The high radiation regime may pose a problem for dosimetry-based techniques (e.g. luminescence). The unique isotopic composition of nitrogen in the Martian atmosphere may permit a Mars-specific chronometer for tracing the time-evolution of the atmosphere and of lithic phases with trapped atmospheric gases. Other Mars-specific chronometers include measurement of gas fluxes and accumulation of platinum group elements (PGE) in the regolith. Putting collected samples into geologic context is deemed essential, as is using multiple techniques on multiple samples. If in situ measurements are restricted to a single technique it must be shown to give consistent results on multiple samples, but in all cases, using two or more techniques (e.g. on the same lander) will reduce error. While there is no question that returned samples will yield the best ages, in situ techniques have the potential to be flown on multiple missions providing a larger data set and broader context in which to place the more accurate dates. ?? 2004 Elsevier B.V. All rights reserved.

  3. Mars chronology: assessing techniques for quantifying surficial processes

    NASA Technical Reports Server (NTRS)

    Doran, Peter T.; Clifford, Stephen M.; Forman, Steven L.; Nyquist, Larry; Papanastassiou, Dimitri A.; Stewart, Brian W.; Sturchio, Neil C.; Swindle, Timothy D.; Cerling, Thure; Kargel, Jeff

    2004-01-01

    Currently, the absolute chronology of Martian rocks, deposits and events is based mainly on crater counting and remains highly imprecise with epoch boundary uncertainties in excess of 2 billion years. Answers to key questions concerning the comparative origin and evolution of Mars and Earth will not be forthcoming without a rigid Martian chronology, enabling the construction of a time scale comparable to Earth's. Priorities for exploration include calibration of the cratering rate, dating major volcanic and fluvial events and establishing chronology of the polar layered deposits. If extinct andor extant life is discovered, the chronology of the biosphere will be of paramount importance. Many radiometric and cosmogenic techniques applicable on Earth and the Moon will apply to Mars after certain baselines (e.g. composition of the atmosphere, trace species, chemical and physical characteristics of Martian dust) are established. The high radiation regime may pose a problem for dosimetry-based techniques (e.g. luminescence). The unique isotopic composition of nitrogen in the Martian atmosphere may permit a Mars-specific chronometer for tracing the time-evolution of the atmosphere and of lithic phases with trapped atmospheric gases. Other Mars-specific chronometers include measurement of gas fluxes and accumulation of platinum group elements (PGE) in the regolith. Putting collected samples into geologic context is deemed essential, as is using multiple techniques on multiple samples. If in situ measurements are restricted to a single technique it must be shown to give consistent results on multiple samples, but in all cases, using two or more techniques (e.g. on the same lander) will reduce error. While there is no question that returned samples will yield the best ages, in situ techniques have the potential to be flown on multiple missions providing a larger data set and broader context in which to place the more accurate dates.

  4. Calcium-41 concentration in terrestrial materials: prospects for dating of pleistocene samples

    SciTech Connect

    Henning, W.; Bell, W.A.; Billquist, P.J.; Glagola, B.G.; Kutschera, W.; Liu, Z.; Lucas, H.F.; Paul, M.; Rehm, K.E.; Yntema, J.L.

    1987-05-08

    Calcium-41 bas been suggested as a new tool for radiometric dating in the range of 10/sup 5/ to 10/sup 6/ years. The concentration of cosmogenic calcium-41 in natural samples of terrestrial origin has now been determined by high-sensitivity accelerator mass spectrometry after pre-enrichment in calcium-41 with an isotope separator. Ratios of calcium-41 to total calcium between 2 x 10/sup -14/ and 3 x 10/sup -15/ were measured for samples of contemporary bovine bone and from limestone deposits. Some prospects for the use of calcium-41 for dating Middle and Late Pleistocene bone and for other geophysical applications are discussed.

  5. Dating conflicts: rethinking dating violence and youth conflict.

    PubMed

    Adelman, Madelaine; Kil, Sang Hea

    2007-12-01

    Dating couples are tied to each other's friends who have expectations about dating, such as who constitutes an acceptable date and how to balance friendship and dating. We explore the place of friends in dating conflicts (i.e., conflicts and violence associated with heterosexual teen dating) and ask: (a) How are friends implicated in teen dating/violence not only as targets or confidants, but also as participants in conflict that stems from their friends' relationships, and (b) in what ways do dating conflicts conserve or challenge the power of gender and sexual conformity that underlies heterosexual dating and dating violence? PMID:18046043

  6. Understanding Teen Dating Violence

    MedlinePLUS

    ... prevent dating violence, we need to know how big the problem is, where it is, and who it affects. CDC learns about a problem by gathering and studying data. Step 2: Identify risk and protective factors It ...

  7. Dating the Vinland Map

    SciTech Connect

    2013-01-04

    Scientists from Brookhaven National Laboratory, the University of Arizona, and the Smithsonian Institution used carbon-dating technology to determine the age of a controversial parchment that might be the first-ever map of North America.

  8. Dating the Vinland Map

    ScienceCinema

    None

    2013-07-17

    Scientists from Brookhaven National Laboratory, the University of Arizona, and the Smithsonian Institution used carbon-dating technology to determine the age of a controversial parchment that might be the first-ever map of North America.

  9. Teen Dating Violence

    MedlinePLUS

    ... Research Featured Topic: Prevent Gang Membership Featured Topic: School Violence Data & Statistics Risk & Protective Factors Prevention Prevention Tools & ... suicide Additionally, youth who are victims of dating violence in high school are at higher risk for victimization during college. ...

  10. Reintroducing radiometric surface temperature into the Penman-Monteith formulation

    NASA Astrophysics Data System (ADS)

    Mallick, Kaniska; Boegh, Eva; Trebs, Ivonne; Alfieri, Joseph G.; Kustas, William P.; Prueger, John H.; Niyogi, Dev; Das, Narendra; Drewry, Darren T.; Hoffmann, Lucien; Jarvis, Andrew J.

    2015-08-01

    Here we demonstrate a novel method to physically integrate radiometric surface temperature (TR) into the Penman-Monteith (PM) formulation for estimating the terrestrial sensible and latent heat fluxes (H and ?E) in the framework of a modified Surface Temperature Initiated Closure (STIC). It combines TR data with standard energy balance closure models for deriving a hybrid scheme that does not require parameterization of the surface (or stomatal) and aerodynamic conductances (gS and gB). STIC is formed by the simultaneous solution of four state equations and it uses TR as an additional data source for retrieving the "near surface" moisture availability (M) and the Priestley-Taylor coefficient (?). The performance of STIC is tested using high-temporal resolution TR observations collected from different international surface energy flux experiments in conjunction with corresponding net radiation (RN), ground heat flux (G), air temperature (TA), and relative humidity (RH) measurements. A comparison of the STIC outputs with the eddy covariance measurements of ?E and H revealed RMSDs of 7-16% and 40-74% in half-hourly ?E and H estimates. These statistics were 5-13% and 10-44% in daily ?E and H. The errors and uncertainties in both surface fluxes are comparable to the models that typically use land surface parameterizations for determining the unobserved components (gS and gB) of the surface energy balance models. However, the scheme is simpler, has the capabilities for generating spatially explicit surface energy fluxes and independent of submodels for boundary layer developments. This article was corrected on 27 AUG 2015. See the end of the full text for details.

  11. Wafer-level radiometric performance testing of uncooled microbolometer arrays

    NASA Astrophysics Data System (ADS)

    Dufour, Denis G.; Topart, Patrice; Tremblay, Bruno; Julien, Christian; Martin, Louis; Vachon, Carl

    2014-03-01

    A turn-key semi-automated test system was constructed to perform on-wafer testing of microbolometer arrays. The system allows for testing of several performance characteristics of ROIC-fabricated microbolometer arrays including NETD, SiTF, ROIC functionality, noise and matrix operability, both before and after microbolometer fabrication. The system accepts wafers up to 8 inches in diameter and performs automated wafer die mapping using a microscope camera. Once wafer mapping is completed, a custom-designed quick insertion 8-12 ?m AR-coated Germanium viewport is placed and the chamber is pumped down to below 10-5 Torr, allowing for the evaluation of package-level focal plane array (FPA) performance. The probe card is electrically connected to an INO IRXCAM camera core, a versatile system that can be adapted to many types of ROICs using custom-built interface printed circuit boards (PCBs). We currently have the capability for testing 384x288, 35 ?m pixel size and 160x120, 52 ?m pixel size FPAs. For accurate NETD measurements, the system is designed to provide an F/1 view of two rail-mounted blackbodies seen through the Germanium window by the die under test. A master control computer automates the alignment of the probe card to the dies, the positioning of the blackbodies, FPA image frame acquisition using IRXCAM, as well as data analysis and storage. Radiometric measurement precision has been validated by packaging dies measured by the automated probing system and re-measuring the SiTF and Noise using INO's pre-existing benchtop system.

  12. Radiometric calibration of a polarization-sensitive sensor

    SciTech Connect

    Ahmad, S.P.; Markham, B.L. NASA, Goddard Space Flight Center, Greenbelt, MD )

    1992-11-01

    The radiometric accuracy of a sensor is adversely affected by scene polarization if its optical system is sensitive to polarization. Tests performed on the reflective bands of the NS001 Thematic Mapper simulator, an aircraft multispectral scanner, show that it is very sensitive to the polarization state of the incoming radiations. For 100 percent linearly polarized light, errors in the measured intensity vary from -40 to +40 percent, depending on the scan angle and spectral band. To estimate polarization-induced errors in the intensity measured at aircraft level, the intensity and polarization of the atmospheric radiances were simulated using a realistic earth-atmosphere radiative transfer model. For the polarization of atmospheric radiances in the solar meridian plane over a vegetated target, intensity errors may range from -10 to + 10 percent. The polarization-induced errors are highest in the shortest NS001 spectral band (0.450-0.525 microns) because of large atmospheric polarizations contributed by Rayleigh particles and small diluting effects caused by the small contributions of weakly polarized radiations coming from aerosols and the surface. Depending on the illumination and view angles, the errors in derived surface reflectance due to the radiance errors can be very large. In particular, for large off-nadir view angles in the forward scattered direction when the sun is low, the relative errors in the derived surface reflectance can be as large as 4 to 5 times the relative error in the radiances. Polarization sensitivity errors cannot be neglected for the shorter wavelengths when the surface reflectance contribution to atmospheric radiances is very small. 40 refs.

  13. Food Product Dating

    MedlinePLUS

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... Food Product Dating / Food Product Dating Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  14. An automated method for relative radiometric correction performed through spectral library based classification and comparison

    NASA Astrophysics Data System (ADS)

    D'Elia, C.; Ruscino, S.

    2012-11-01

    In this paper we propose a method to perform automated radiometric correction of remotely sensed multispectral hyperspectral images. The effects of atmosphere, as well as the calibration errors which the satellite sensors may present, may be compensated by performing the radiometric correction operation in order to achieve good performances in different applications, such as classification and change detection. As far as the change detection is concerned, relative radiometric correction is particularly interesting since it deals with images which have to be compared and since in this context an absolute correction may be characterized by a high complexity. One method for performing radiometric correction of multispectral images can be based on a least-square approach: considering one image as the reference one and the other as a linearly scaled version of the reference one, the linear coefficients can be calculated by using a set of control points conveniently chosen. Unfortunately, the choice of control points is a tricky operation, strictly connected to the specific application. In this paper we propose an automated method for performing relative radiometric correction of multispectral remotely sensed images, in which the choice of the control points is based on a comparison of the spectral content of those images to the spectral response of known materials. Specifically, we perform a vector quantization of the images separately, considering N quantization levels represented by N known materials' signatures properly selected. Then the quantized images are compared in order to identify the areas classified as belonging to the same class, so identified by the same quantization index which will make the subset of control points that should be used for performing relative radiometric correction. Experimental results showed that choosing points characterized by an homogeneous spectral content for radiometric correction improves the performances of specific image processing algorithms, such as change detection and classification algorithms.

  15. Laser photothermal radiometric instrumentation for fast in-line industrial steel hardness inspection and case depth measurements

    SciTech Connect

    Guo Xinxin; Sivagurunathan, Konesh; Garcia, Jose; Mandelis, Andreas; Giunta, Salvatore; Milletari, Salvatore

    2009-03-01

    A contact-free, nondestructive laser photothermal radiometric instrumentation technique was developed to meet industrial demand for on-line steel hardness inspection and quality control. A series of industrial steel samples, flat or curvilinear, with different effective hardness case depths ranging between 0.21 and 1.78 mm were measured. The results demonstrated that three measurement parameters (metrics) extracted from fast swept-sine photothermal excitation and measurements, namely, the phase minimum frequency fmin, the peak or trough frequency width W, and the area S, are complementary for evaluating widely different ranges of hardness case depth: fmin is most suitable for large case depths, and W and S for small case depths. It was also found that laser beam angular inclination with respect to the surface plane of the sample strongly affects hardness measurement resolution and that the phase frequency maximum is more reliable than the amplitude maximum for laser beam focusing on the sample surface.

  16. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Souce for System-Level Testing of Optical Sensors

    NASA Technical Reports Server (NTRS)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2015-01-01

    This work describes the development of an improved vacuum compatible flat plate radiometric source used for characterizing and calibrating remote optical sensors, in situ, throughout their testing period. The original flat plate radiometric source was developed for use by the VIIRS instrument during the NPOESS Preparatory Project (NPP). Following this effort, the FPI has had significant upgrades in order to improve both the radiometric throughput and uniformity. Results of the VIIRS testing with the reconfigured FPI are reported and discussed.

  17. Hydrogen-Dating Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Krco, Marko; Goldsmith, P. F.; Li, D.

    2006-12-01

    Using improved techniques for measuring the atomic hydrogen content of dark clouds utilizing HI Narrow Self-Absorption (HINSA) in conjunction with more traditional methods for determining the molecular hydrogen content we are able to estimate the HI/H2 ratio in an expanded sample of dark cloud cores. Using a simple evolutionary model we can estimate the ages of individual clouds or regions. We present the results of our survey of 36 dark cloud cores which exhibit HINSA absorption features. This dating procedure imposes constraints on the time scale for star formation in dense molecular regions.

  18. Microwave and Millimeter Wave Forward Modeling Results from the 2004 North Slope of Alaska Arctic Winter Radiometric Experiment

    SciTech Connect

    Westwater, E.R.; Cimini, D.; Klein, M.; Leuski, V.; Mattioli, V.; Gasiewski, A.J.; Dowlatshahi, S.; Liljegren, J.S.; Lesht, B.M.; Shaw, J.A.

    2005-03-18

    The 2004 Arctic Winter Radiometric Experiment was conducted at the North Slope of Alaska (NSA) Atmospheric Radiation Measurement (ARM) Program field site near Barrow, Alaska from March 9 to April 9, 2004. The goals of the experiment were: to study the microwave and millimeter wave radiometric response to water vapor and clouds during cold and dry conditions; to obtain data for forward model studies at frequencies ranging from 22.235 to 400 GHz, to demonstrate new Environmental Technology Laboratory's (ETL) radiometric receiver and calibration technology and to compare both radiometric and in situ measurements of water vapor.

  19. The nature of the systematic radiometric error in the MGS TES spectra

    NASA Astrophysics Data System (ADS)

    Pankine, Alexey A.

    2015-05-01

    Several systematic radiometric errors are known to affect the data collected by the Thermal Emission Spectrometer (TES) onboard Mars Global Surveyor (MGS). The time-varying wavenumber dependent error that significantly increased in magnitude as the MGS mission progressed is discussed in detail. This error mostly affects spectra of cold (nighttime and polar caps) surfaces and atmospheric spectra in limb viewing geometry. It is proposed here that the source of the radiometric error is a periodic sampling error of the TES interferograms. A simple model of the error is developed that allows predicting its spectral shape for any viewing geometry based on the observed uncalibrated spectrum. Comparison of the radiometric errors observed in the TES spaceviews and those predicted by the model shows an excellent agreement. Spectral shapes of the errors for nadir and limb spectra are simulated based on representative TES spectra. In nighttime and limb spectra, and in spectra of cold polar regions, these radiometric errors can result in an error of ±3-5 K in the retrieved atmospheric and surface temperatures, and significant errors in retrieved opacities of atmospheric aerosols. The model of the TES radiometric error presented here can be used to improve the accuracy of the TES retrievals and increase scientific return from the MGS mission.

  20. (abstract) Deep Space Network Radiometric Remote Sensing Program

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.

    1994-01-01

    Planetary spacecraft are viewed through a troposphere that absorbs and delays radio signals propagating through it. Tropospheric water, in the form of vapor, cloud liquid,and precipitation , emits radio noise which limits satellite telemetry communication link performance. Even at X-band, rain storms have severely affected several satellite experiments including a planetary encounter. The problem will worsen with DSN implementation of Ka-band becausecommunication link budgets will be dominated by tropospheric conditions. Troposphere-induced propagation delays currently limit VLBI accuracy and are significant sources of error for Doppler tracking. Additionally, the success of radio science programs such as satellite gravity wave experiments and atmospheric occultation experiments depends on minimizing the effect of watervapor-induced prop agation delays. In order to overcome limitations imposed by the troposphere, the Deep Space Network has supported a program of radiometric remote sensing. Currently, water vapor radiometers (WVRs) and microwave temperature profilers (MTPs) support many aspects of the Deep Space Network operations and research and development programs. Their capability to sense atmospheric water, microwave sky brightness, and atmospheric temperature is critical to development of Ka-band telemetry systems, communication link models, VLBI, satellite gravity waveexperiments, and r adio science missions. During 1993, WVRs provided data for propagation mode development, supp orted planetary missions, and demonstrated advanced tracking capability. Collection of atmospheric statistics is necessary to model and predict performance of Ka-band telemetry links, antenna arrays, and radio science experiments. Since the spectrum of weather variations has power at very long time scales, atmospheric measurements have been requested for periods ranging from one year to a decade at each DSN site. The resulting database would provide reliable statistics on daily, monthly, and seasonal variations. Only long-term monitoring will prevent biases from being introduced by an exceptionally wet or dry year. Support for planetary missions included tropospheric calibration for the recent Mars Observer gravity wave experiments and Ka-band link experiment (KaBLE). Additionally, several proposed radio science experiments such as profiling planetary atmospheres using satellite occultations and Ka-band gravitational wave searches require advanced radiometer technology development. Finally, there has been a consistent advanced technology program to advance satellite navigational and tracking capabilities. This year that included an experiment with radiometer based tropospheric calibration for a series of VLBI catalog measurements.

  1. Plutonium age dating reloaded

    NASA Astrophysics Data System (ADS)

    Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Mayer, Klaus; Prohaska, Thomas

    2014-05-01

    Although the age determination of plutonium is and has been a pillar of nuclear forensic investigations for many years, additional research in the field of plutonium age dating is still needed and leads to new insights as the present work shows: Plutonium is commonly dated with the help of the 241Pu/241Am chronometer using gamma spectrometry; in fewer cases the 240Pu/236U chronometer has been used. The age dating results of the 239Pu/235U chronometer and the 238Pu/234U chronometer are scarcely applied in addition to the 240Pu/236U chronometer, although their results can be obtained simultaneously from the same mass spectrometric experiments as the age dating result of latter. The reliability of the result can be tested when the results of different chronometers are compared. The 242Pu/238U chronometer is normally not evaluated at all due to its sensitivity to contamination with natural uranium. This apparent 'weakness' that renders the age dating results of the 242Pu/238U chronometer almost useless for nuclear forensic investigations, however turns out to be an advantage looked at from another perspective: the 242Pu/238U chronometer can be utilized as an indicator for uranium contamination of plutonium samples and even help to identify the nature of this contamination. To illustrate this the age dating results of all four Pu/U clocks mentioned above are discussed for one plutonium sample (NBS 946) that shows no signs of uranium contamination and for three additional plutonium samples. In case the 242Pu/238U chronometer results in an older 'age' than the other Pu/U chronometers, contamination with either a small amount of enriched or with natural or depleted uranium is for example possible. If the age dating result of the 239Pu/235U chronometer is also influenced the nature of the contamination can be identified; enriched uranium is in this latter case a likely cause for the missmatch of the age dating results of the Pu/U chronometers.

  2. Identification of Worldwide Optimal Pseudo-Invariant Calibration Sites for Post-Launch Radiometric Calibration of Earth Observation Satellite Sensors

    NASA Astrophysics Data System (ADS)

    Basnet, Bikash

    The primary objective of this project was to identify extremely stable sites on the Earth's surface known as Pseudo-Invariant Calibration Sites (PICS). A recently developed technique for monitoring the long term stability of earth observing satellite sensors was based on using PICS for detecting trends in the radiometric response of these instruments. In a manner analogous to using a known reflectance or radiance source in a laboratory, this method relied on the stability of the Earth's surface over time. To perform this task, the Landsat 5 Thematic Mapper (TM) sensor was used to identify the most invariant locations or PICS on the Earth's surface by monitoring the temporal stability of carefully selected ground sites on Earth. Ground sites were selected to ensure minimal surface and atmosphere change that could affect the observed reflectance, thus enabling a means to monitor the radiometric stability of space instruments. PICS mainly consist of playa (dry lakebeds), salt flats and desert sand sites located in arid regions with low probability of cloud cover, spatial homogeneity, constant surface spectral reflectance and BRDF over short and long periods of time. Potential PICS were evaluated and chosen for the study based upon their size, location, climate characteristics, and scene availability in the USGS data archive. A grid-based approach was used to determine and recommend the areas of each PICS that was considered most invariant. This approach relied on the PICS min-noise algorithm developed recently at SDSU, where the mean radiance of each grid was calculated for each scene and the grid with lowest temporal standard deviation of the mean was considered as most invariant. The Levene Test of equality of variance was used to optimize the size of worldwide PICS, and uncertainties using those optimal locations were calculated for comparison. A catalog of recommended sites was developed: seven in the Sahara Desert and one each in North America, South America, Australia, Middle East and Asia. Sahara sites exhibit uncertainties of 2% or less in VNIR and 2--3% in SWIR across most sites. Global sites exhibit uncertainties in the range of 1--5%. Finally, as a validation exercise, Landsat-7 Enhanced Thematic Mapper plus (ETM+) reflective band radiometric gain trends were estimated using the optimal locations of four worldwide PICS.

  3. The Realities of Date Rape.

    ERIC Educational Resources Information Center

    Presley, Cara; Watson, Jennifer; Williams, Audrey R.

    This poster presentation addresses the issue of date rape, specifically in the college environment. Highlighted are date rape statistics, demographics, and date rape drugs. Also discussed are date rape warnings and prevention strategies. It is concluded that college and university administrators must place the issue of date rape and acquaintance…

  4. From Romance to Rocket Science: Speed Dating in Higher Education

    ERIC Educational Resources Information Center

    Muurlink, Olav; Poyatos Matas, Cristina

    2011-01-01

    This article is the first comprehensive review of speed dating in the tertiary sector. While speed dating has its origins as a networking technique to connect singles, it has only more recently made its way into the academy. Since 2005 universities world-wide have begun to adopt speed dating protocols as a tool for building research culture. An

  5. Date palm: Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The future of date palm, as a dioecious, monocot fruit tree largely depends on (1) developing advanced knowledge and information about the dynamics, management, and sustainability of the tree as a central component of the oasis agro-ecosystem, and (2) in-depth understanding of the genetic diversity ...

  6. Confronting Dating Violence.

    ERIC Educational Resources Information Center

    McNulty, Raymond J.; Heller, Daniel A.; Binet, Tracy

    1997-01-01

    To be safe havens for children, schools cannot address the intellect only. Brattleboro (Vermont) Union High School went beyond academics by sponsoring a performance of "The Yellow Dress," a powerful one-woman play about a teenage victim of dating violence. The production challenged participants to unite school and community, intellect and heart.

  7. The Dating Game.

    ERIC Educational Resources Information Center

    Zerger, Monte J.

    1998-01-01

    Presents activities to cultivate the tendency to see special qualities in numbers that can be played on certain calendar days. Includes games on the constant of the day, Fibonacci and golden ratio dates, primes, powers, December 25, and the day of the year. (ASK)

  8. Radiometric calibration and processing procedure for reflective bands on LANDSAT-4 protoflight Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Barker, J. L.; Abrams, R. B.; Ball, D. L.; Leung, K. C.

    1984-01-01

    The radiometric subsystem of NASA's LANDSAT-4 Thematic Mapper (TM) sensor is described. Special emphasis is placed on the internal calibrator (IC) pulse shapes and timing cycle. The procedures for the absolute radiometric calibration of the TM channels with a 122-centimeter integrating sphere and the transfer of radiometric calibration from the channels to the IC are reviewed. The use of the IC to calibrate TM data in the ground processing system consists of pulse integration, pulse averaging, IC state identification, linear regression analysis, and histogram equalization. An overview of the SCROUNGE-era (before August 1983) method is presented. Procedural differences between SCROUNGE and the TIPS-era (after July 1983) and the implications of these differences are discussed.

  9. Absolute radiometric calibration of Als intensity data: effects on accuracy and target classification.

    PubMed

    Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Vain, Ants; Kukko, Antero; Hyyppä, Juha; Kaasalainen, Mikko

    2011-01-01

    Radiometric calibration of airborne laser scanning (ALS) intensity data aims at retrieving a value related to the target scattering properties, which is independent on the instrument or flight parameters. The aim of a calibration procedure is also to be able to compare results from different flights and instruments, but practical applications are sparsely available, and the performance of calibration methods for this purpose needs to be further assessed. We have studied the radiometric calibration with data from three separate flights and two different instruments using external calibration targets. We find that the intensity data from different flights and instruments can be compared to each other only after a radiometric calibration process using separate calibration targets carefully selected for each flight. The calibration is also necessary for target classification purposes, such as separating vegetation from sand using intensity data from different flights. The classification results are meaningful only for calibrated intensity data. PMID:22346660

  10. Preparation of a new autonomous instrumented radiometric calibration site: Gobabeb, Namib Desert

    NASA Astrophysics Data System (ADS)

    Greenwell, Claire; Bialek, Agnieszka; Marks, Amelia; Woolliams, Emma; Berthelot, Batrice; Meygret, Aim; Marcq, Sbastien; Bouvet, Marc; Fox, Nigel

    2015-10-01

    A new permanently instrumented radiometric calibration site for high/medium resolution imaging satellite sensors is currently under development, focussing on the visible and near infra-red parts of the spectrum. The site will become a European contribution to the Committee on Earth Observation Satellites (CEOS) initiative RadCalNet (Radiometric Calibration Network). The exact location of the permanent monitoring instrumentation will be defined following the initial site characterisation. The new ESA/CNES RadCalNet site will have a robust uncertainty budget and its data fully SI traceable through detailed characterisation and calibration by NPL of the instruments and artefacts to be used on the site. This includes a CIMEL sun photometer (the permanent instrumentation) an ASD FieldSpec spectroradiometer, Gonio Radiometric Spectrometer System (GRASS), and reference reflectance standards.

  11. Absolute Radiometric Calibration of ALS Intensity Data: Effects on Accuracy and Target Classification

    PubMed Central

    Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Vain, Ants; Kukko, Antero; Hyypp, Juha; Kaasalainen, Mikko

    2011-01-01

    Radiometric calibration of airborne laser scanning (ALS) intensity data aims at retrieving a value related to the target scattering properties, which is independent on the instrument or flight parameters. The aim of a calibration procedure is also to be able to compare results from different flights and instruments, but practical applications are sparsely available, and the performance of calibration methods for this purpose needs to be further assessed. We have studied the radiometric calibration with data from three separate flights and two different instruments using external calibration targets. We find that the intensity data from different flights and instruments can be compared to each other only after a radiometric calibration process using separate calibration targets carefully selected for each flight. The calibration is also necessary for target classification purposes, such as separating vegetation from sand using intensity data from different flights. The classification results are meaningful only for calibrated intensity data. PMID:22346660

  12. Landsat-7 ETM+: 12 years on-orbit reflective-band radiometric performance

    USGS Publications Warehouse

    Markham, B.L.; Haque, M.O.; Barsi, J.A.; Micijevic, E.; Helder, D.L.; Thome, K.J.; Aaron, D.; Czapla-Myers, J. S.

    2012-01-01

    The Landsat-7 ETM+ sensor has been operating on orbit for more than 12 years, and characterizations of its performance have been ongoing over this period. In general, the radiometric performance of the instrument has been remarkably stable: 1) noise performance has degraded by 2% or less overall, with a few detectors displaying step changes in noise of 2% or less; 2) coherent noise frequencies and magnitudes have generally been stable, though the within-scan amplitude variation of the 20 kHz noise in bands 1 and 8 disappeared with the failure of the scan line corrector and a new similar frequency noise (now about 18 kHz) has appeared in two detectors in band 5 and increased in magnitude with time; 3) bias stability has been better than 0.25 DN out of a normal value of 15 DN in high gain; 4) relative gains, the differences in response between the detectors in the band, have generally changed by 0.1% or less over the mission, with the exception of a few detectors with a step response change of 1% or less; and 5) gain stability averaged across all detectors in a band, which is related to the stability of the absolute calibration, has been more stable than the techniques used to measure it. Due to the inability to confirm changes in the gain (beyond a few detectors that have been corrected back to the band average), ETM+ reflective band data continues to be calibrated with the prelaunch measured gains. In the worst case, some bands may have changed as much as 2% in uncompensated absolute calibration over the 12 years.

  13. Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard.

    PubMed

    Smith, Allan W; Lorentz, Steven R; Stone, Thomas C; Datla, Raju V

    2012-01-01

    The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty(1) of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth's atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties. PMID:26900523

  14. Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard

    PubMed Central

    Smith, Allan W.; Lorentz, Steven R.; Stone, Thomas C.; Datla, Raju V.

    2012-01-01

    The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty1 of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth’s atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties. PMID:26900523

  15. Dating the tree of life.

    PubMed

    Benton, Michael J; Ayala, Francisco J

    2003-06-13

    The relative merits of molecular and paleontological dates of major branching points in the tree of life are currently debated. In some cases, molecular date estimates are up to twice as old as paleontological dates. However, although it is true that paleontological dates are often too young (missing fossils), molecular dates are often too old (statistical bias). Intense study of the dating of major splits in the tree of mammals has shown rapprochement as fossil dates become older and molecular dates become younger. PMID:12805535

  16. Dendrochemical Dating of Tephra Layers

    NASA Astrophysics Data System (ADS)

    Ort, M. H.; Sheppard, P. R.; Speakman, J.; Anderson, K. A.; Elson, M. D.; Siebe G., C.

    2004-12-01

    Dating eruptions in the past 1000 years can be difficult with 14C, as production rates have varied. Tree-ring dating has been used, with eruptions presumably causing thin rings. We are developing a dendrochemical dating technique that may give more confidence to such dates. When a tephra is deposited, soil chemistry may change and many components of the glassy matrix are mobile and available for leaching into the soil and, hence, to plants. If some components were scarce prior to the eruption, the content in tree rings may increase and serve as a chemical marker of the eruption onset. LA-ICP-MS analysis of tree cores allows earlywood from each ring to be analyzed. We are currently investigating whether acid dissolution will produce similar results and precision with small sample sizes. The 1943-1952 CE eruption of Paricutin, Michoacan, Mexico, deposited a thick tephra in a conifer forest. Analyses of tree cores show that pre-eruption P concentrations of a few ppm increased an order of magnitude within the first two years after the onset of the eruption and then dropped steadily during the rest of the eruption to 10-15 ppm, which was then maintained for decades. Ca and Sr dropped during the eruption but rebounded immediately afterward. These three elements appear immobile in the wood, as steep compositional gradients occur across rings. The Paricutin tephra has 0.2-0.4 wt% P2O5. Analyses of soils and tephra obtained by the Bray method (a weak HCl leaching intended to mimic leaching in slightly acid soils) yield values of 2-17 ppm available phosphorus, fairly high values for this area. The Sunset Crater eruption near Flagstaff, Arizona, was dated at 1064 CE based on the onset of thin tree rings in three beams from structures at Wupatki village, 20 km north of the volcano. Our analyses of this wood show pronounced increases in P, Ca, Sr, Mg, and Mn in the early 1080s CE. Currently, we are investigating Jeffrey pine reaction to the mid-1600s CE Cinder Cone eruption at Lassen Volcanic National Park, California.

  17. Comparison of diverse methods for the correction of atmospheric effects on LANDSAT and SKYLAB images. [radiometric correction in Brazil

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Camara, G.; Dias, L. A. V.; Mascarenhas, N. D. D.; Desouza, R. C. M.; Pereira, A. E. C.

    1982-01-01

    Earth's atmosphere reduces a sensors ability in currently discriminating targets. Using radiometric correction to reduce the atmospheric effects may improve considerably the performance of an automatic image interpreter. Several methods for radiometric correction from the open literature are compared leading to the development of an atmospheric correction system.

  18. A Sounding Rocket Mission Concept to Acquire High-Resolution Radiometric Spectra Spanning the 9 nm - 31 nm Wavelength Range

    NASA Technical Reports Server (NTRS)

    Krause, L. Habash; Cirtain, Jonathan; McGuirck, Michael; Pavelitz, Steven; Weber, Ed.; Winebarger, Amy

    2012-01-01

    When studying Solar Extreme Ultraviolet (EUV) emissions, both single-wavelength, two- dimensional (2D) spectroheliograms and multi-wavelength, one-dimensional (1D) line spectra are important, especially for a thorough understanding of the complex processes in the solar magnetized plasma from the base of the chromosphere through the corona. 2D image data are required for a detailed study of spatial structures, whereas radiometric (i.e., spectral) data provide information on relevant atomic excitation/ionization state densities (and thus temperature). Using both imaging and radiometric techniques, several satellite missions presently study solar dynamics in the EUV, including the Solar Dynamics Observatory (SDO), Hinode, and the Solar-Terrestrial Relations Observatory (STEREO). The EUV wavelengths of interest typically span 9 nm to 31 nm, with the shorter wavelengths being associated with the hottest features (e.g., intense flares and bright points) and the longer wavelengths associated with cooler features (e.g., coronal holes and filaments). Because the optical components of satellite instruments degrade over time, it is not uncommon to conduct sounding rocket underflights for calibration purposes. The authors have designed a radiometric sounding rocket payload that could serve as both a calibration underflight for and a complementary scientific mission to the upcoming Solar Ultraviolet Imager (SUVI) mission aboard the GOES-R satellite (scheduled for a 2015 launch). The challenge to provide quality radiometric line spectra over the 9-31 nm range covered by SUVI was driven by the multilayer coatings required to make the optical components, including mirrors and gratings, reflective over the entire range. Typically, these multilayers provide useful EUV reflectances over bandwidths of a few nm. Our solution to this problem was to employ a three-telescope system in which the optical components were coated with multilayers that spanned three wavelength ranges to cover the three pairs of SUVI bands. The complete system was designed to fit within the Black Brandt-IX 22.-diameter payload skin envelope. The basic optical path is that of a simple parabolic telescope in which EUV light is focused onto a slit and shutter assembly and imaged onto a normal-incidence diffraction grating, which then disperses the light onto a 2048 2048 CCD sensor. The CCD thus records 1D spatial information along one axis and spectral information along the other. The slit spans 40 arc-minutes in length, thus covering a solar diameter out to +/- 1.3 solar radii. Our operations concept includes imaging at three distinct positions: the north-south meridian, the northeast-southwest diagonal, and real-time pointing at an active region. Six 10-second images will be obtained at each position. Fine pointing is provided by the SPARCS-VII attitude control system typically employed on Black Brandt solar missions. Both before and after launch, all three telescopes will be calibrated with the EUV line emission source and monochromater system at NASA's Stray Light Facility at Marshall Spaceflight Center. Details of the payload design, operations concept, and data application will be presented.

  19. Surface and aerosol models for use in radiative transfer codes. [for radiometric calibration of Landsat-5 Thematic Mapper (TM)

    NASA Technical Reports Server (NTRS)

    Hart, Quinn J.

    1991-01-01

    Absolute reflectance-based radiometric calibrations of Landsat-5 Thematic Mapper (TM) are improved with the inclusion of a method to invert optical-depth measurements to obtain aerosol-particle size distributions, and a non-Lambertian surface reflectance model. The inverted size distributions can predict radiances varying from the previously assumed jungian distributions by as much as 5 percent, though the reduction in the estimated error is less than one percent. Comparison with measured diffuse-to-global ratios show that neither distribution consistently predicts the ratio accurately, and this is shown to be a large contributor to calibration uncertainties. An empirical model for the surface reflectance of White Sands, using a two-degree polynomial fit as a function of scattering angle, was employed. The model reduced estimated errors in radiance predictions by up to one percent. Satellite calibrations dating from October, 1984 were reprocessed using the improved methods and linear estimations of satellite counts per unit radiance versus time since launch were determined which showed a decrease over time for the first four bands.

  20. Dating Violence among College Students

    ERIC Educational Resources Information Center

    Iconis, Rosemary

    2013-01-01

    Dating violence is a significant problem on college campuses. More than one-fifth of the undergraduate dating population are physically abused by their dating partners and an even greater percentage are psychologically abused. Researchers have identified risk factors for college student dating violence. Preventive interventions are strongly…

  1. Lifetime radiometric calibration of HJ-1A/B CCD sensor using Dunhuang Gobi site

    NASA Astrophysics Data System (ADS)

    Han, Qijin; Zhang, Xuewen; Liu, Li; Wang, Aichun

    2014-11-01

    Dunhuang Gobi site, a pseudo-invariant ground target, has been extensively used to calibrate the remote sensing instruments because of its high spatial and spectral uniformity and good temporal stability. Four Charge Coupled Device (CCD) sensors onboard HUANGJING-A/B (HJ-1A/B) satellites have been running 5-years since launched in 2008, and provided important remote sensing data for land surface reflectance retrieval, bio/geophysical variables estimation and environment pollution /disaster monitoring. The radiometric performance of HJ-1A/B CCD may change after launched because of many factors, thus, we have carried out many ground measurement campaigns at a pseudo-invariant test site-Dunhuang gobi to perform radiometric calibration of these sensors. This article describes the characteristics of Dunhuang gobi site and lifetime radiometric calibration monitoring results obtained for four CCD sensors. The results indicate that the long-term changes in calibration coefficients trending exceeding the dark-noise changes are primarily due to the drifts in the CCD radiometric responsivity, and the degradations of HJ-1A/B CCD are from -2.3%/year to -9.5%/year.

  2. Spectral and radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Vane, Gregg; Chrien, Thomas G.; Miller, Edward A.; Reimer, John H.

    1987-01-01

    The laboratory spectral and radiometric calibration of the AVIRIS science data collected since 1987 is described. The instrumentation and procedures used in the calibration are discussed and the accuracy achieved in the laboratory as determined by measurement and calculation is compared with the requirements. Instrument performance factors affecting radiometry are described. The paper concludes with a discussion of future plans.

  3. Spectral and radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Vane, Gregg; Chrien, Thomas G.; Miller, Edward A.; Reimer, John H.

    1988-01-01

    The laboratory spectral and radiometric calibration of the AVIRIS science data collected since 1987 is described. The instrumentation and procedures used in the calibration are discussed and the accuracy achieved in the laboratory as determined by measurement and calculation is compared with the requirements. Instrument performance factors affecting radiometry are described. The paper concludes with a discussion of future plans.

  4. Radiometric ages of brachyuran crabs from the Galapagos spreading-center hydrothermal ventfield

    SciTech Connect

    Bennett, J.T.; Turekian, K.K.

    1984-09-01

    The ages of four crab carapaces from the Galapagos spreading-center hydrothermal ventfield were determined radiometrically using members of the U and Th decay chains. One animal had an age of 0.1 years and therefore had undergone molting just before collection; the other three had last molted 3-4 years before collection.

  5. IMPLICATIONS OF RADIOMETRIC-AERODYNAMIC TEMPERATURE DIFFERENCES FOR HEAT FLUX ESTIMATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the application of radiometric surface temperature observations for heat flux computations in numerical models, it is necessary to consider differences between the so-called aerodynamic temperature, which is the model-derived temperature that relates to the efficiency of heat exchange between t...

  6. Texture analysis of radiometric signatures of new sea ice forming in Arctic leads

    NASA Technical Reports Server (NTRS)

    Eppler, Duane T.; Farmer, L. Dennis

    1991-01-01

    Analysis of 33.6-GHz, high-resolution, passive microwave images suggests that new sea ice accumulating in open leads is characterized by a unique textural signature which can be used to discriminate new ice forming in this environment from adjacent surfaces of similar radiometric temperature. Ten training areas were selected from the data set, three of which consisted entirely of first-year ice, four entirely of multilayer ice, and three of new ice in open leads in the process of freezing. A simple gradient operator was used to characterize the radiometric texture in each training region in terms of the degree to which radiometric gradients are oriented. New ice in leads has a sufficiently high proportion of well-oriented features to distinguish it uniquely from first-year ice and multiyear ice. The predominance of well-oriented features probably reflects physical processes by which new ice accumulates in open leads. Banded structures, which are evident in aerial photographs of new ice, apparently give rise to the radiometric signature observed, in which the trend of brightness temperature gradients is aligned parallel to lead trends. First-year ice and multiyear ice, which have been subjected to a more random growth and process history, lack this banded structure and therefore are characterized by signatures in which well-aligned elements are less dominant.

  7. Adjustments to the MODIS Terra Radiometric Calibration and Polarization Sensitivity in the 2010 Reprocessing

    NASA Technical Reports Server (NTRS)

    Meister, Gerhard; Franz, Bryan A.

    2011-01-01

    The Moderate-Resolution Imaging Spectroradiometer (MODIS) on NASA s Earth Observing System (EOS) satellite Terra provides global coverage of top-of-atmosphere (TOA) radiances that have been successfully used for terrestrial and atmospheric research. The MODIS Terra ocean color products, however, have been compromised by an inadequate radiometric calibration at the short wavelengths. The Ocean Biology Processing Group (OBPG) at NASA has derived radiometric corrections using ocean color products from the SeaWiFS sensor as truth fields. In the R2010.0 reprocessing, these corrections have been applied to the whole mission life span of 10 years. This paper presents the corrections to the radiometric gains and to the instrument polarization sensitivity, demonstrates the improvement to the Terra ocean color products, and discusses issues that need further investigation. Although the global averages of MODIS Terra ocean color products are now in excellent agreement with those of SeaWiFS and MODIS Aqua, and image quality has been significantly improved, the large corrections applied to the radiometric calibration and polarization sensitivity require additional caution when using the data.

  8. Radiometric normalization and cloud detection of optical satellite images using invariant pixels

    NASA Astrophysics Data System (ADS)

    Lin, Chao-Hung; Lin, Bo-Yi; Lee, Kuan-Yi; Chen, Yi-Chen

    2015-08-01

    Clouds in optical satellite images can be a source of information for water measurement or viewed as contaminations that obstruct landscape observations. Thus, the use of a cloud detection method that discriminates cloud and clear-sky pixels in images is necessary in remote sensing applications. With the aid of radiometric correction/normalization, previous methods utilized temporal and spectral information as well as cloud-free reference images to develop threshold-based cloud detection filters. Although this strategy can effectively identify cloud pixels, the detection accuracy mainly relies on the successful radiometric correction/normalization and reference image quality. Relative radiometric normalization generally suffers from cloud covers, while multi-temporal cloud detection is sensitive to the radiometric normalization quality. Thus, the current study proposes a method based on weighted invariant pixels for both processes. A set of invariant pixels is extracted from a time series of cloud-contaminated images by using the proposed weighted principle component analysis, after which multi-temporal images are normalized with the selected invariant pixels. In addition, a reference image is generated for each cloud-contaminated image using invariant pixels with a weighting scheme. In the experiments, image sequences acquired by the Landsat-7 Enhanced Thematic Mapper Plus sensor are analyzed qualitatively and quantitatively to evaluate the proposed method. Experimental results indicate that F-measures of cloud detections are improved by 1.1-6.9% using the generated reference images.

  9. ESTIMATING SUBPIXEL SURFACE TEMPERATURES AND ENERGY FLUXES FROM THE VEGETATION INDEX-RADIOMETRIC TEMPERATURE RELATIONSHIP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Routine (i.e., daily to weekly) monitoring of surface energy fluxes, particularly evapotranspiration (ET), using satellite observations of radiometric surface temperature has not been feasible at high pixel resolution because of the low frequency in satellite coverage over the region of interest (i...

  10. Landsat-8 Operational Land Imager (OLI) radiometric performance on-orbit

    USGS Publications Warehouse

    Morfitt, Ron; Barsi, Julia A.; Levy, Raviv; Markham, Brian L.; Micijevic, Esad; Ong, Lawrence; Scaramuzza, Pat; Vanderwerff, Kelly

    2015-01-01

    Expectations of the Operational Land Imager (OLI) radiometric performance onboard Landsat-8 have been met or exceeded. The calibration activities that occurred prior to launch provided calibration parameters that enabled ground processing to produce imagery that met most requirements when data were transmitted to the ground. Since launch, calibration updates have improved the image quality even more, so that all requirements are met. These updates range from detector gain coefficients to reduce striping and banding to alignment parameters to improve the geometric accuracy. This paper concentrates on the on-orbit radiometric performance of the OLI, excepting the radiometric calibration performance. Topics discussed in this paper include: signal-to-noise ratios that are an order of magnitude higher than previous Landsat missions; radiometric uniformity that shows little residual banding and striping, and continues to improve; a dynamic range that limits saturation to extremely high radiance levels; extremely stable detectors; slight nonlinearity that is corrected in ground processing; detectors that are stable and 100% operable; and few image artifacts.

  11. Radiometric sand-mud characterisation in the Rhine-Meuse estuary. Part A. Fingerprinting

    NASA Astrophysics Data System (ADS)

    van Wijngaarden, M.; Venema, L. B.; De Meijer, R. J.; Zwolsman, J. J. G.; Van Os, B.; Gieske, J. M. J.

    2002-02-01

    The composition of the underwater sediment bed is often defined in terms of the mud (<63 ?m) or sand (>63 and <2000 ?m) content. Mud and sand differ considerably in their content of (natural) radionuclides. Radionuclide concentrations are highest in the clay minerals that form a significant part of the mud fraction. A study was initiated in the Hollandsch Diep and Haringvliet, two semi-stagnant fresh water basins in the southwestern part of Rhine-Meuse Estuary (The Netherlands), to investigate whether radionuclides can be utilised to determine the sand and mud content of aquatic sediments. The radiometric fingerprint was assessed based on sediment samples with different composition, provenance and age. Differences in provenance (Rhine versus Meuse) could be discriminated by the 40K content of the sediment. Differences in age or composition, in terms of mineralogy, organic matter or carbonate content, only slightly affected the radiometric characteristics based on 232Th and 238U. On the other hand, no reliable correlation between 40K and the mud content was obtained; therefore, 40K is excluded from the fingerprint. The fingerprints based on the 232Th and 238U contents characterise mud (<63 ?m) and sand (>63 ?m) as: 46.21.9 Bq/kg 238U and 9.30.9 Bq/kg 238U and 45.61.9 Bq/kg 232Th and 9.70.9 Bq/kg 232Th, respectively. The assessed radiometric fingerprint allows a quantitative interpretation of the mud and sand content through the total 238U+ 232Th activity. This interpretation is confirmed by the high correlation ( R2=0.96) for the mud percentages obtained from radiometric analysis and those by laser diffraction in the laboratory. It can be concluded that radiometric sedimentology provides a tool for reliable sediment characterisation. New perspectives are opened when radiometric fingerprints are combined with in situ radiometric characterisation of sediments, which will be presented in part B of this paper (this issue).

  12. Vulcanism and Radiocarbon Dates

    DOE R&D Accomplishments Database

    Libby, L. M.; Libby, W. F.

    1972-10-01

    We consider whether the long term perturbation of radiocarbon dates, which is known to be approximately a sin function of period about 8000 years and amplitude of about 8% peak-to-peak, could have been caused in any major part by vulcanism. We conclude that this is not the case. On the contrary, present day volcanoes are a far less important source of inert CO{sub 2} (about 100 fold less) than is man's burning of fossil fuels which has caused the Suess dilution of about 2%. (auth)

  13. Radiocarbon dating of ancient rock paintings

    SciTech Connect

    Ilger, W.A.; Hyman, M.; Rowe, M.W.; Southon, J.

    1995-06-20

    This report presents progress made on a technique for {sup 14}C dating pictographs. A low-temperature oxygen plasma is used coupled with high-vacuum technologies to selectively remove C-containing material in the paints without contamination from inorganic carbon from rock substrates or accretions.

  14. Three-dimensional radiometric aperture synthesis microscopy for security screening

    NASA Astrophysics Data System (ADS)

    Salmon, Neil A.; Bowring, Nick

    2014-10-01

    The three dimensional (3D) aperture synthesis imaging technique investigated here is a generalisation of the classic twodimensional radio astronomy technique with refinements for the near-field so it can be applied a personnel security screening portal. This technique can be viewed as a novel form of diffraction emission tomography and extends previous 3D aperture synthesis imaging research using matrix inversion techniques [1]. Simulations using three-dimensional Fourier transforms to create three-dimensional images from simulated three-dimensional visibility functions illustrate the Abbe microscopy resolution should be achievable in three dimensions simultaneously in a single sensor. The field-of-view is demonstrated to be limited by Fresnel scale effects and a means to over coming this by processing sub-sets of local visibility functions with different phase centres throughout the imaging volume is presented. The applications of this technique to a full 3D imaging security screening portal is explored and a route to extending simulation software for market driven imaging scenarios is discussed.

  15. Dynamic noise corrected hyperspectral radiometric calibration in the SWIR range using a supercontinuum laser

    NASA Astrophysics Data System (ADS)

    Keresztes, Janos C.; Aernouts, Ben; Koshel, R. J.; Saeys, Wouter

    2015-09-01

    As line scanning short wave infrared (SWIR) hyperspectral imaging (HSI) is a growing field in the food industry, it is important to select efficient illumination designs to image contaminants with high contrast and low noise. Illumination systems can efficiently be compared and optimized through the use of ray tracing simulations. However, these simulations provide illumination patterns in absolute radiometric units while HSI systems typically provide relative measurements. To bridge this gap, a supercontinuum laser and monochromator setup was used in this study to calibrate a SWIR HSI imager in spectral radiometric units. For the radiometric calibration, an integrating sphere (IS) was illuminated with the monochromatic laser light, while both a high sensitivity photodiode and the hyperspectral camera were positioned at different ports of the IS to measure the diffuse light synchronously. For each spectral band, the radiance observed by the imager corresponding to a line was detected using image analysis, while the remainder of the image was used to sample the noise of the sensor. Laser power fluctuations were monitored using a power meter coupled with a thermal sensor, allowing for their correction. As these measurements were time consuming, while InGaAs based sensors are very sensitive to thermal drift, the dark current was sampled frequently to avoid noise time drifts. This approach allowed correcting for 6% of temporal noise fluctuations. A per-pixel linear radiometric model was fitted with an R2 of 0:94+/-0:3 and used to transfer the measured light distribution of a halogen spot with and without a diffuser into absolute radiometric units. This allowed comparing measurements with the results of ray tracing.

  16. Using the Dunhuang test site to monitor the radiometric stability of the ZY-3 multispectral sensor

    NASA Astrophysics Data System (ADS)

    Zhang, Xuewen; Han, Qijin; Liu, Li

    2014-11-01

    The ZY-3 satellite plays an important role in agriculture, forestry, water conservancy, ecological environment, and so on since its successfully running. In order to achieve continuity, stability and reliability of the remote sensing data, and improve quantitative application level of the ZY-3 satellite data, an accurate sensor radiometric calibration is essential. Because ZY-3 satellite doesn't have onboard calibration system, in-fight filed absolute radiometric calibration as a means to effective monitor the radiometric stability.This paper uses multi-day, multi-field at the Dunhuang test site to calibrate the ZY-3 multispectral sensor. The experiment obtained a synchronization measurement data on the August 18, 23 and 28, respectively. The two of ground surface were selected for measuring reflectance, which middling reflectance field (20%) and high reflectance field (40%). At the time of the ZY-3 overpass on the site, synchronous measure surface reflectance of ground targets, atmospheric optical characteristics parameters, such as atmospheric aerosol optical depth, atmospheric columnar water vapor content. Then use the radiative transfer model to estimate the top of atmosphere (TOA) radiance for MSS band. Radiometric calibration coefficient of MSS band was estimated by comparing the TOA radiance with average digital number of the MSS image. Based on multi-day, multi-field, and the real-time measurement at the Dunhuang site, radiometric calibration for ZY-3 MSS was successfully performed using reflectance-based method and calibration coefficients for MSS bands were obtained as well. According to contrast between in-fight calibration and the prelaunch, it was shown that the response of MSS changed at some extent after launch, especially band 1 and band 4. As a result, it was quite essential to update calibration coefficient timely and periodically in order to monitor the change of ZY-3 MSS better and to improve the quantitative application of MSS data as well.

  17. Multi-temporal MODIS-Landsat Data Fusion for Relative Radiometric Normalization and gap Filling of Landsat Data

    NASA Astrophysics Data System (ADS)

    Roy, D. P.; Ju, J.

    2007-12-01

    The primary limitation to the utility of Landsat data, other than data cost, is the availability of cloud-free surface observations. As currently only degraded Landsat 5 and Landsat ETM+ systems are acquiring data, and only a single successor Landsat Data Continuity Mission sensor is scheduled, a potential alternative to provide more surface observations is the fusion of Landsat data with data from other remote sensing systems. A semi-physical fusion approach that uses the MODIS BRDF/Albedo surface anisotropy characterization product and Landsat ETM+ data to predict 30m Landsat reflectance on any date is presented. The methodology may be used for ETM+ cloud and SLC-off gap filling and for relative radiometric normalization. It does not require any tuning parameters and so may be automated, it is applied on a per-pixel basis and is unaffected by the presence of missing or contaminated neighboring Landsat pixels. The methodology and spatially explicit results are presented for two Landsat acquisitions at three Landsat scenes, one in Africa and two in the U.S., selected to encompass a range of land cover land use types, and temporal variations in solar illumination, land cover, and phenology. Summary statistics of the difference between the predicted and observed ETM+ reflectance (prediction residual) are compared with the difference between the ETM+ reflectance observed on the two dates (temporal residual) and with respect to the MODIS BRDF model parameter quality. For all three Landsat scenes, and for all bands, except one short wavelength band, the mean prediction residual is smaller than the mean temporal residual, typically by a factor two. This fusion methodology may be applied to any high spatial resolution satellite data with similar spectral bands as MODIS and where the sensor viewing and solar illumination geometry can be accurately derived.

  18. An In-Situ Rb-Sr Dating & Organics Characterization Instrument For A MER+ Sized Rover

    NASA Astrophysics Data System (ADS)

    Anderson, F.; Whitaker, T.; Nowicki, K.; Zacny, K.; Pierce, J.

    2012-12-01

    We posit that a Mars in-situ geochronology mission that will triage and validate samples for Mars Sample Return (MSR) is technically feasible in the 2018-2022 time frame and addresses the competing scientific, political, and fiscal requirements for flight in this decade.The mission must be responsive to the astrobiological and chronological science goals of the MEPAG, Decadal Survey (DS), and E2E-iSAG, and avoid the MSR appearance of long term political commitment and cost. These requirements can best be accomplished by a rover with a coring drill. JPL has reassessed the MER landing system performance, and determined that the system is capable of significantly higher landed mass (~40-60 kg plus reserve), allowing more sophisticated instruments to be carried. The instrument package is comprised of a time of flight (TOF) mass spectrometer combined with a laser desorption resonance ionization source to sensitively measure isobar free Rb-Sr isotopes for geochronology and organics characterization. The desorption laser is also used with a μRaman/LIBS for mineral characterization, which in combination with the TOF, will additionally provide measurements of K-Ar isotopes for a second form of radiometric dating. The laser desorption resonance ionization mass spectrometry (LDRIMS) technique avoids the interference and mass resolution issues associated with geochronology measurements, and has miniaturization potential. A sample is placed in the TOF mass spectrometer and surface atoms, molecules, and ions are desorbed with a 213 nm laser. Ions are suppressed by an electric field and the plume of expanding particles is present for many μs, during which it is first illuminated with laser light tuned to ionize only Sr, and then 1-3 μs later, for Rb. We have partially miniaturized the instrument, including Sr lasers, ablation laser, and mass spectrometer, and will soon to start using the instrument for field measurements. Our current prototype can measure the isotope ratio of lab standards with 10 ppm net Sr or Rb to a precision of ±0.1% (1σ), with a sensitivity of 1:10^10 in ~15 minutes. Before working with high value samples, we are validating the technique on terrestrial materials such as the Boulder Creek Granite (BCG). Using LDRIMS, we have succeeded at producing a moderate precision date for BCG of 1.72±0.087 Ga (n=288, MSWD=1; ±0.60 Ga for MSWD=2). Our mission feeds forward into MSR by validating that the collected samples are astrobiologically and geochronologically relevant, and triages those samples by scientific priority for return by MSR. Figure 1: Calibrated repeat isochron of the BCG.

  19. Not only Chauvet: dating Aurignacian rock art in Altxerri B Cave (northern Spain).

    PubMed

    González-Sainz, C; Ruiz-Redondo, A; Garate-Maidagan, D; Iriarte-Avilés, E

    2013-10-01

    The discovery and first dates of the paintings in Grotte Chauvet provoked a new debate on the origin and characteristics of the first figurative Palaeolithic art. Since then, other art ensembles in France and Italy (Aldène, Fumane, Arcy-sur-Cure and Castanet) have enlarged our knowledge of graphic activity in the early Upper Palaeolithic. This paper presents a chronological assessment of the Palaeolithic parietal ensemble in Altxerri B (northern Spain). When the study began in 2011, one of our main objectives was to determine the age of this pictorial phase in the cave. Archaeological, geological and stylistic evidence, together with radiometric dates, suggest an Aurignacian chronology for this art. The ensemble in Altxerri B can therefore be added to the small but growing number of sites dated in this period, corroborating the hypothesis of more complex and varied figurative art than had been supposed in the early Upper Palaeolithic. PMID:24012252

  20. Structure and dating errors in the geologic time scale and periodicity in mass extinctions

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    Structure in the geologic time scale reflects a partly paleontological origin. As a result, ages of Cenozoic and Mesozoic stage boundaries exhibit a weak 28-Myr periodicity that is similar to the strong 26-Myr periodicity detected in mass extinctions of marine life by Raup and Sepkoski. Radiometric dating errors in the geologic time scale, to which the mass extinctions are stratigraphically tied, do not necessarily lessen the likelihood of a significant periodicity in mass extinctions, but do spread the acceptable values of the period over the range 25-27 Myr for the Harland et al. time scale or 25-30 Myr for the DNAG time scale. If the Odin time scale is adopted, acceptable periods fall between 24 and 33 Myr, but are not robust against dating errors. Some indirect evidence from independently-dated flood-basalt volcanic horizons tends to favor the Odin time scale.

  1. The biology behind lichenometric dating curves.

    PubMed

    Loso, Michael G; Doak, Daniel F

    2006-03-01

    Lichenometry is used to date late-Holocene terminal moraines that record glacier fluctuations. Traditionally, it relies upon dating curves that relate diameters of the largest lichens in a population to surface ages. Although widely used, the technique remains controversial, in part because lichen biology is poorly understood. We use size-frequency distributions of lichens growing on well-dated surfaces to fit demographic models for Rhizocarpon geographicum and Pseudophebe pubescens, two species commonly used for lichenometry. We show that both species suffer from substantial mortality of 2-3% per year, and grow slowest when young-trends that explain a long-standing contradiction between the literatures of lichenometry and lichen biology. Lichenometrists interpret the shape of typical dating curves to indicate a period of rapid juvenile "great growth," contrary to the growth patterns expected by biologists. With a simulation, we show how the "great growth" pattern can be explained by mortality alone, which ensures that early colonists are rarely found on the oldest surfaces. The consistency of our model predictions with biological theory and observations, and with dozens of lichenometric calibration curves from around the world, suggests opportunities to assess quantitatively the accuracy and utility of this common dating technique. PMID:16237538

  2. Accelerator radiocarbon dating: new applications and capabilities

    SciTech Connect

    Cresswell, R.G.; Beukens, R.P.; Lee, H.W.

    1985-01-01

    As with new advances in any field, radiocarbon dating by accelerator mass spectrometry has to be treated with some scepticism until it has proven itself against the conventional techniques. By the direct atom counting of the radioactive carbon isotope, C-14, rather than the counting of the beta particles, any background is eliminated and microgram-sized samples of a solid graphite-like target can be analyzed in a few hours instead of many days. The IsoTrace laboratory has completed a comparative analysis with materials dated by the conventional method and has shown excellent agreement, yielding an accuracy better than 1% and a precision of 0.3%. For samples less than 10,000 years old, a precision of 1.0% is routinely obtained, while, for samples less than 2000 years old, precision of 0.3% is possible. Dates can also be routinely obtained from materials up to 50,000 years old. With the small sample size and high precision, greater resolution when dating recent materials may be obtained. Materials that previously proved impossible to date due to small sample size or the nature of the material (e.g. high value, weathering etc.) may now readily be subjected to scrutiny. Fragments, rather than bulk samples, may be dated, facilitating significant stratigraphic resolution and correlation in a wide variety of situations.

  3. Healthy Dating: A Mixed-Gender Date Rape Workshop.

    ERIC Educational Resources Information Center

    Holcomb, Derek R.; And Others

    1993-01-01

    Describes a college-level, mixed-gender date rape workshop provided to over 1,400 students. The workshop included student discussion. Evaluations indicated students were positive about the experience. Very few felt uncomfortable discussing date rape in mixed groups, and nearly all agreed that date rape was a topic worthy of discussion. (SM)

  4. CASSINI/VIMS-V at Jupiter: Radiometric calibration test and data results

    NASA Astrophysics Data System (ADS)

    Coradini, A.; Filacchione, G.; Capaccioni, F.; Cerroni, P.; Adriani, A.; Brown, R. H.; Langevin, Y.; Gondet, B.

    2004-06-01

    During the Cassini-Huygens flyby of Jupiter in December 2000, VIMS-V acquired multispectral data cubes of Jupiter's atmosphere. The visual and infrared imaging spectrometer-visual channel (VIMS-V) is one of the principal contributions of Italian Space Agency (ASI) to the Cassini-Huygens mission to Saturn. VIMS-V is an imaging spectrometer operating in the wavelength range 300- 1050 nm, with a (nominal) spectral resolution of 7.3 nm, and a (nominal) spatial resolution of 500 ?rad. VIMS-V is boresighted with the VIMS-IR channel operating in the wavelength range 0.8- 5.1 ?m. During the early phases of the Cassini mission, the spacecraft encountered Venus (June 23, 1999), followed shortly thereafter by a flyby of the Earth. During the Earth flyby the Moon (August 17, 1999) was observed. Following the Earth-Moon flyby, the spacecraft encountered Jupiter (closest approach on December 31, 2000), and during the roughly 6 months prior to Jupiter closest approach a series of observations were made of most of the objects in the Jovian system. We have determined the instrumental transfer function of VIMS-V using the Moon and Venus day side data. This transfer function was then used to remove instrumental effects from the Jupiter data and to convert raw instrumental response numbers to spectral radiance from the target. It was thus possible to study the spectral variability of Jupiter's atmosphere across its disk using data from both the visual (V) and infrared (IR) channels of VIMS. In this paper we discuss the main results obtained by the V channel. We have analyzed the principal spectral features of Jupiter atmosphere, and in particular, the spatial variation of methane and ammonia absorption bands over the Jovian disk. Using the instrument's spatial mapping capabilities we have investigated the nature of the absorption band in the spectrum of Jupiter's atmosphere at 929 nm that is consistent with the presence of ammonia or water vapor. After comet Shoemaker-Levy 9 impacted Jupiter, water vapor was considered the most likely cause of the 929 nm absorption feature, but our data indicate that ammonia is the source of this band. Other analyses were performed using standard techniques such as forming band ratios and removal of the continuum. Our analyses confirm previous ground or satellite based observations. We were also able to verify the instrument radiometric calibration, using observations conducted during the close encounters with Venus and the Moon.

  5. Sample detection and analysis techniques for electrophoretic separation

    NASA Technical Reports Server (NTRS)

    Falb, R. D.; Hughes, K. E.; Powell, T. R.

    1975-01-01

    Methods for detecting and analyzing biological agents suitable for space flight operations were studied primarily by literature searches which were conducted of cell separation techniques. Detection methods discussed include: photometrometric, electric, radiometric, micrometry, ultrasonic, microscopic, and photographic. A bibliography, and a directory of vendors are included along with an index of commercial hardware.

  6. Violence in Adolescent Dating Relationships

    ERIC Educational Resources Information Center

    Jouriles, Ernest N.; Platt, Cora; McDonald, Renee

    2009-01-01

    Beginning with a definition of dating and dating violence among adolescents, this article explores the factors which impact such violence. It concludes with a review of two school-based prevention/intervention programs (Safe Dates and The Youth Relationships Project). (Contains 1 table.)

  7. Reconstructing level changes and assessing evidence for tectonic and glacial-rebound induced tilting of the Lake Wakatipu basin, New Zealand using novel techniques for correlating and dating paleoshorelines

    NASA Astrophysics Data System (ADS)

    McColl, S. T.; Stahl, T. A.; Cook, S.

    2013-12-01

    Glacial-rebound signals have not previously been identified or isolated from tectonic processes in the New Zealand landscape. This contrasts with other parts of the world where glacial-unloading has caused tens to hundreds of meters of uplift and increased fault activity. The aim of this research was to quantify the magnitude and timing of post-glacial lake-level changes and deformation of the Lake Wakatipu basin, New Zealand. Abandoned shorelines up to 43 m above the modern water-level had previously been suggested to be tilted. Accurate measurement of the magnitude and timing of tilting would provide a unique attempt to extract a glacial-rebound signal from the tectonically-overprinted New Zealand landscape. Paleo-shoreline profiles were surveyed along the lake using GPS and existing air-borne LiDAR datasets. The shoreline profiles were correlated based on elevation and numerically cross-correlated to assess potential progressive offset. The results reveal negligible elevation differences, in conflict with previous suggestions of shoreline tilting. The timing of lake lowering was assessed with Schmidt hammer exposure-age and optically stimulated luminescence (OSL) dating of a flight of alluvial terraces directly correlated with the shorelines. The ages suggest formation of the lake by ~17.1 +/- 2.6 ka, which is assumed to be the approximate age for initial formation of the highest and most prominent preserved shoreline. Abandonment of this high-stand shoreline is thought to have commenced at ~12 ka when lake drainage switched to a new outlet, and was followed by gradual lowering (of about 20 m in 8-10 kyr). Lowering accelerated at about 2 ka, rapidly achieving 26-29 m of lowering before then reversing by 3-6 m to attain the present-day level. Glacial-rebound induced uplift or fault activity in the last 18 kyr has not been recorded by paleo-shorelines of Lake Wakatipu. We suggest that a glacial-isostatic signal is not present in the data because either glacial rebound occurred very quickly after ice retreat, or that any uplift was uniformly distributed over the length of the lake. These results invite investigation of other glaciated areas of New Zealand to explore whether this pattern is spatially and temporally consistent.

  8. Uncertainty propagation algorithm from the radiometric calibration to the restored earth observation radiance.

    PubMed

    Guorui, Jia; Huijie, Zhao; Hao, Lei

    2014-04-21

    The uncertainty of the radiometric calibration affects the accuracy of the earth observation (EO) radiance restored from the remote sensing digital number (DN) data. However, it has not been intensively analyzed whether they are equivalent to each other. The algorithm to deduce the uncertainty of the restored EO radiance in the solar-reflective spectral range (400-2500 nm) along the uncertainty propagation chain in the radiometric calibration process is proposed. It was validated compared with the traditional calibration uncertainty algorithm through an example of calibrating an imaging spectrometer. The interval about the real EO radiance and the corresponding level of confidence was reported as a result, which shows the possibility to accurately expressing the quality of the restored EO radiance following the rules used in the field of metrology. PMID:24787833

  9. The effects of vegetation cover on the radar and radiometric sensitivity to soil moisture

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Dobson, M. C.; Brunfeldt, D. R.; Razani, M.

    1982-01-01

    The measured effects of vegetation canopies on radar and radiometric sensitivity to soil moisture are compared to emission and scattering models. The models are found to predict accurately the measured emission and backscattering for various crop canopies at frequencies between 1.4 and 5.0 GHz, especially at theta equal to or less than 30 deg. Vegetation loss factors, L(theta), increase with frequency and are found to be dependent upon canopy type and water content. In addition, the radiometric power absorption coefficient of a mature corn canopy is 1.75 times that calculated for the radar. Comparison of an L-band radiometer with a C-band radar shows the two systems to be complementary in terms of accurate soil moisture sensing over the extreme range of naturally occurring soil moisture conditions.

  10. Extreme Ultraviolet Variability Experiment (EVE) Multiple EUV Grating Spectrographs (MEGS): Radiometric Calibrations and Results

    NASA Technical Reports Server (NTRS)

    Hock, R. A.; Woods, T. N.; Crotser, D.; Eparvier, F. G.; Woodraska, D. L.; Chamberlin, P. C.; Woods, E. C.

    2010-01-01

    The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et al. . In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments.

  11. Radiometric calibration and atmospheric correction of satellite and aircraft data for FIFE

    NASA Technical Reports Server (NTRS)

    Goetz, Scott J.; Markham, Brian L.; Newcomer, Jeffery A.

    1992-01-01

    The satellite and aircraft radiometric calibration and atmospheric correction work carried out as part of the first International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) are summarized. A large volume (120 Gbytes) of radiometric data were acquired and derived from a number of different instruments on a variety of platforms. The same basic procedure was applied to each instrument: derive the most recent calibration coefficients for converting sensor counts to reflective spectral radiances; correct the radiances for earth-sun distance variations and incident solar spectral irradiance within the bandpass of each respective instrument channel at the top of the atmosphere; characterize the atmosphere for aerosols and absorbing gases; and derive apparent surface reflectance by correcting the exoatmospheric values for atmospheric attenuation. The same basic approach was used for surface temperature derivation. The results of this processing were verified by surface measurements, and corroborated by sensor intercomparisons.

  12. Results of a thermoluminescence radiometric survey in Takala area of China's Tarim basin

    SciTech Connect

    Siegel, F.R. ); Vaz, J.E. ); Su, J. )

    1993-01-11

    This paper reports on a thermoluminescence dosimeter (TLD) radiometric study of the near-surface radiation flux which was done as an adjunct to oil exploration research in the Takala area, Tarim basin, western China. About 80 sq km of the basin were evaluated using lithium fluoride (LiF) TLDs buried at about 0.5 m; Rn and [Delta]C (anomalous carbonate) measurements were made in this region as well. Small target areas were defined in the region by low value TL radiometric signals. Comparative measurements of Rn and [Delta]C were not as effective as TL in defining small areas for follow-up seismic work or in revealing the structural trends. The structural nature of the area was mimicked by the near-surface radiometries distribution pattern determined by TLDs and suggested the possibility of fault-influenced traps in the subsurface.

  13. First realisation of the Space Absolute Radiometric Reference (SARR) during the ATLAS 2 flight period

    NASA Technical Reports Server (NTRS)

    Crommelynck, D.; Fichot, A.; Lee, R. B., III; Romero, J.

    1995-01-01

    A number of different solar constant observations all made from space during the ATLAS 2 mission have been gathered and compared to each other. The Sun did not have a single sunspot during several days. As eight of the radiometric channels were all within 0.1%, the mean of the observations has been used to determine a set of adjustment factors providing de facto the definition of the Space Absolute Radiometric Reference (SARR). The differential absolute radiometers of Solar Constant (SOLCON) experiment and the Solar Variability-1 (SOVA 1) experiment, as well as the SOVA 2 and Active Cavity Radiometer (ACR) radiometers that have been brought back to the Earth may, if used in the same conditions, reproduce and maintain the SARR for the future.

  14. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS): Inflight radiometric calibration and the determination of surface reflectance

    NASA Technical Reports Server (NTRS)

    Conel, J. E.; Vane, G.; Green, R. O.; Alley, R. E.; Carere, V.; Gabell, A.; Bruegge, C. J.

    1988-01-01

    The inflight radiometric performance of AVIRIS is presented together with a comparison of methods of recovering surface spectral reflectance from the data. Performance is evaluated by comparing radiance predicted from AVIRIS with radiance generated from the LOWIRAN 6 atmospheric model and measured surface reflectance. Comparisons show apparent agreement to within a few percent between 1800 and 2450 nm. Between 600 and 1800 nm the response of AVIRIS is systematically low by as much as 70 percent, and between 400 and 600 nm it is higher than expected. These problems are traced to thermal distortions of the instrument, and to detachment during flight of optical fibers connecting foreoptics to two of four spectrometers in the instrument. Of three methods studied, an empirical one involving calibration curves constructed from field reflectance measurements returns accurate predictions of the surface reflectance independent of the actual radiometric significance of the flight data.

  15. Initial on-orbit radiometric calibration of the Suomi NPP VIIRS reflective solar bands

    NASA Astrophysics Data System (ADS)

    Lei, Ning; Wang, Zhipeng; Fulbright, Jon; Lee, Shihyan; McIntire, Jeff; Chiang, Kwofu; Xiong, Xiaoxiong

    2012-09-01

    The on-orbit radiometric response calibration of the VISible/Near InfraRed (VISNIR) and the Short-Wave InfraRed (SWIR) bands of the Visible/Infrared Imager/Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (NPP) satellite is carried out through a Solar Diffuser (SD). The transmittance of the SD screen and the SD's Bidirectional Reflectance Distribution Function (BRDF) are measured before launch and tabulated, allowing the VIIRS sensor aperture spectral radiance to be accurately determined. The radiometric response of a detector is described by a quadratic polynomial of the detector's digital number (dn). The coefficients were determined before launch. Once on orbit, the coefficients are assumed to change by a common factor: the F-factor. The radiance scattered from the SD allows the determination of the F-factor. In this Proceeding, we describe the methodology and the associated algorithms in the determination of the F-factors and discuss the results.

  16. An information theory characterization of radar images and a new definition for radiometric resolution

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Shanmugan, K. S.; Holtzman, J. C.

    1982-01-01

    The noise properties of the radar image formation process are used in the present modeling of a communication channel in which the desired target properties are the information transmitted, and the final image represents the received signal. The average information rate over this communication channel is calculated together with appropriate bounds and approximations, and is found to be small on a per-sample basis. As a result, many samples must be averaged to allow for the discrimination, or classification, of several levels of target reflectivity. These information rate properties are consistent with known results concerning target detection and image quality in speckle, and the rate is applicable to the definition of radar image radiometric resolution. Radiometric resolution is functionally related to the degree of noncoherent averaging performed by the sensor.

  17. Contact sensitivity in mice evaluated by means of ear swelling and a radiometric test

    SciTech Connect

    Baeck, O.; Larsen, A.

    1982-04-01

    Contact sensitivity to picryl chloride was investigated by means of the ear swelling test and a radiometric test in order to establish optimal experimental conditions for these assays. Contact sensitivity was demonstrated as soon as 2 days after sensitization, with a maximum reaction 3-4 days after sensitization, when a 48 hr test reaction was registered. The test reaction was followed for 72 hr and maximum was arrived at after 24 hr and 48 hr for the ear swelling test and the radiometric test, respectively. Optimal sensitization was reached with a 7% solution of picryl chloride and a maximum test reaction was found with 0.75-1.0% picryl chloride. It is concluded that both assays measure contact sensitivity in quantitative terms and a future replacement of the guinea pig maximization test is discussed.

  18. Improved ground calibration results from Southwest Research Institute Ultraviolet Radiometric Calibration Facility (UV-RCF)

    NASA Astrophysics Data System (ADS)

    Davis, Michael W.; Greathouse, Thomas K.; Gladstone, G. Randall; Retherford, Kurt D.; Slater, David C.; Stern, S. Alan; Versteeg, Maarten H.

    2014-07-01

    Four compact planetary ultraviolet spectrographs have been built by Southwest Research Institute and successfully operated on different planetary missions. These spectrographs underwent a series of ground radiometric calibrations before delivery to their respective spacecraft. In three of the four cases, the in-flight measured sensitivity was approximately 50% lower than the ground measurement. Recent tests in the Southwest Research Institute Ultraviolet Radiometric Calibration Facility (UV-RCF) explain the discrepancy between ground and flight results. Revised ground calibration results are presented for the Rosetta-Alice, New Horizons-Alice, the Lunar Reconnaissance Orbiter Lyman- Alpha Mapping Project, and Juno-Ultraviolet Spectrograph (UVS) and are then compared to the original ground and flight calibrations. The improved understanding of the calibration system reported here will result in improved ground calibration of the upcoming Jupiter Icy Moons Explorer (JUICE)-UVS.

  19. Improving Ocean Color Data Products using a Purely Empirical Approach: Reducing the Requirement for Radiometric Calibration Accuracy

    NASA Technical Reports Server (NTRS)

    Gregg, Watson

    2008-01-01

    Radiometric calibration is the foundation upon which ocean color remote sensing is built. Quality derived geophysical products, such as chlorophyll, are assumed to be critically dependent upon the quality of the radiometric calibration. Unfortunately, the goals of radiometric calibration are not typically met in global and large-scale regional analyses, and are especially deficient in coastal regions. The consequences of the uncertainty in calibration are very large in terms of global and regional ocean chlorophyll estimates. In fact, stability in global chlorophyll requires calibration uncertainty much greater than the goals, and outside of modern capabilities. Using a purely empirical approach, we show that stable and consistent global chlorophyll values can be achieved over very wide ranges of uncertainty. Furthermore, the approach yields statistically improved comparisons with in situ data, suggesting improved quality. The results suggest that accuracy requirements for radiometric calibration cab be reduced if alternative empirical approaches are used.

  20. Improved thermal-vacuum compatible flat plate radiometric source for system-level testing of optical sensors

    NASA Astrophysics Data System (ADS)

    Schwarz, Mark A.; Kent, Craig J.; Brown, Steven W.; Woodward, John T.; Lin, Chungsan

    2014-09-01

    In this work, development of a fiber-optically coupled, vacuum-compatible, flat plate radiometric source applicable to the characterization and calibration of remote sensing optical sensors in situ in a thermal vacuum chamber is described. The original flat plate radiometric source configuration's performance was presented at the 2009 Berlin SPIE. Following the original effort, design upgrades were incorporated in order to improve radiometric throughput and uniformity. Results of thermal and radiometric performance, with incorporated upgrades, of a flat plate illumination source in a temperature-controlled vacuum chamber operating at liquid nitrogen temperature are presented. Applications, including use with monochromatic tunable laser sources for the end-to-end system-level testing of large aperture sensors, are briefly discussed.

  1. Production and radiometric measurements of the large particle plutonium oxide non-destructive assay standards

    NASA Astrophysics Data System (ADS)

    Thronas, Denise L.; Wong, Amy S.; Mecklenburg, Sandra L.; Marshall, Robert S.

    2000-07-01

    The Analytical Chemistry Group at Los Alamos National Laboratory (LANL) has produced several sets of working reference materials (WRMs) for the National TRU Waste Program (NTWP) NDA PDP(Non-Destructive Assay Performance Demonstration Program). This paper describes the first example of production of traceable, certified standards containing plutonium oxide in large particle form for the DOE complex. Discussion of the production and radiometric measurements of these NDA standards is included herein.

  2. A procedure for radiometric recalibration of Landsat 5 TM reflective-band data

    USGS Publications Warehouse

    Chander, G.; Haque, M.O.; Micijevic, E.; Barsi, J.A.

    2010-01-01

    From the Landsat program's inception in 1972 to the present, the Earth science user community has been benefiting from a historical record of remotely sensed data. The multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone for this extensive archive. Historically, the radiometric calibration procedure for the L5 TM imagery used the detectors' response to the internal calibrator (IC) on a scene-by-scene basis to determine the gain and offset for each detector. The IC system degraded with time, causing radiometric calibration errors up to 20%. In May 2003, the L5 TM data processed and distributed by the U.S. Geological Survey (USGS) Earth Resources Observation and Science Center through the National Landsat Archive Production System (NLAPS) were updated to use a lifetime lookup-table (LUT) gain model to radiometrically calibrate TM data instead of using scene-specific IC gains. Further modification of the gain model was performed in 2007. The L5 TM data processed using IC prior to the calibration update do not benefit from the recent calibration revisions. A procedure has been developed to give users the ability to recalibrate their existing level-1 products. The best recalibration results are obtained if the work-order report that was included in the original standard data product delivery is available. However, if users do not have the original work-order report, the IC trends can be used for recalibration. The IC trends were generated using the radiometric gain trends recorded in the NLAPS database. This paper provides the details of the recalibration procedure for the following: 1) data processed using IC where users have the work-order file; 2) data processed using IC where users do not have the work-order file; 3) data processed using prelaunch calibration parameters; and 4) data processed using the previous version of the LUT (e.g., LUT03) that was released before April 2, 2007.

  3. Radiometric calibration of DMSP-OLS sensor using VIIRS day/night band

    NASA Astrophysics Data System (ADS)

    Shao, Xi; Cao, Changyong; Zhang, Bin; Qiu, Shi; Elvidge, Christopher; Von Hendy, Michael

    2014-11-01

    Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) has been collecting global night light imaging data for more than 40 years. With the launch of Suomi-NPP satellite in 2011, the Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) represents a major advancement in night time imaging capabilities because it surpasses DMSP-OLS in having broader radiometric measurement range, more accurate radiometric calibration, finer spatial resolution, and better geometric quality. DMSP-OLS sensor does not have on-board calibration and data is recorded as digital number (DN). Therefore, VIIRS-DNB provides opportunities to perform quantitative radiometric calibration of DMSP-OLS sensor. In this paper, vicarious radiometric calibration of DMSP-OLS at night under lunar illumination is performed. Events were selected when satellite flies above Dome C in Antarctic at night and the moon illuminates the site with lunar phase being more than quarter moon. Additional event selection criteria to limit solar and lunar zenith angle range have been applied to ensure no influence of stray light effects and adequate lunar illumination. The data from DMSP-OLS and VIIRS-DNB were analyzed to derive the characteristic radiance or DN for the region of interest. The scaling coefficient for converting DMSP-OLS DN values into radiance is determined to optimally merge the observation of DMSP-OLS into VIIRS-DNB radiance data as a function of lunar phases. Calibrating the nighttime light data collected by the DMSP-OLS sensors into radiance unit can enable applications of using both sensor data and advance the applications of night time imagery data.

  4. The absolute radiometric calibration of the advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Slater, P. N.; Teillet, P. M.; Ding, Y.

    1988-01-01

    The need for independent, redundant absolute radiometric calibration methods is discussed with reference to the Thematic Mapper. Uncertainty requirements for absolute calibration of between 0.5 and 4 percent are defined based on the accuracy of reflectance retrievals at an agricultural site. It is shown that even very approximate atmospheric corrections can reduce the error in reflectance retrieval to 0.02 over the reflectance range 0 to 0.4.

  5. Radiometric calibration and monitoring of NOAA AVHRR data for ISCCP. [International Satellite Cloud Climatology Project

    NASA Technical Reports Server (NTRS)

    Brest, Christopher L.; Rossow, William B.

    1992-01-01

    The methodology developed to monitor the radiometric calibration of NOAA AVHRR data and to normalize succeeding polar orbiters for the International Satellite Cloud Project (ISCCP) is described. Results are given for NOAA-7, -8, and -9 Channel 1 (visible) data. The successful normalization of NOAA-8, and -9, to NOAA-7 permits the ISCCP calibration standard to be maintained over time. A correction for the degradation of NOAA-9 data and an absolute calibration for the entire ISCCP dataset are presented.

  6. A New Automatic System for Angular Measurement and Calibration in Radiometric Instruments

    PubMed Central

    Marquez, Jose Manuel Andujar; Bohrquez, Miguel ngel Martnez; Garcia, Jonathan Medina; Nieto, Francisco Jose Aguilar

    2010-01-01

    This paper puts forward the design, construction and testing of a new automatic system for angular-response measurement and calibration in radiometric instruments. Its main characteristics include precision, speed, resolution, noise immunity, easy programming and operation. The developed system calculates the cosine error of the radiometer under test by means of a virtual instrument, from the measures it takes and through a mathematical procedure, thus allowing correcting the radiometer with the aim of preventing cosine error in its measurements. PMID:22319320

  7. Opportunities to Intercalibrate Radiometric Sensors from International Space Station

    NASA Technical Reports Server (NTRS)

    Roithmayr, C. M.; Lukashin, C.; Speth, P. W.; Young, D. F.; Wielicki, B. A.; Thome, K. J.; Kopp, G.

    2014-01-01

    Highly accurate measurements of Earth's thermal infrared and reflected solar radiation are required for detecting and predicting long-term climate change. Consideration is given to the concept of using the International Space Station to test instruments and techniques that would eventually be used on a dedicated mission, such as the Climate Absolute Radiance and Refractivity Observatory (CLARREO). In particular, a quantitative investigation is performed to determine whether it is possible to use measurements obtained with a highly accurate (0.3%,with 95%confidence) reflected solar radiation spectrometer to calibrate similar, less accurate instruments in other low Earth orbits. Estimates of numbers of samples useful for intercalibration are made with the aid of yearlong simulations of orbital motion. Results of this study support the conclusion that the International Space Station orbit is ideally suited for the purpose of intercalibration between spaceborne sensors.

  8. Opportunities to Intercalibrate Radiometric Sensors From International Space Station

    NASA Technical Reports Server (NTRS)

    Roithmayr, C. M.; Lukashin, C.; Speth, P. W.; Thome, K. J.; Young, D. F.; Wielicki, B. A.

    2012-01-01

    Highly accurate measurements of Earth's thermal infrared and reflected solar radiation are required for detecting and predicting long-term climate change. We consider the concept of using the International Space Station to test instruments and techniques that would eventually be used on a dedicated mission such as the Climate Absolute Radiance and Refractivity Observatory. In particular, a quantitative investigation is performed to determine whether it is possible to use measurements obtained with a highly accurate reflected solar radiation spectrometer to calibrate similar, less accurate instruments in other low Earth orbits. Estimates of numbers of samples useful for intercalibration are made with the aid of year-long simulations of orbital motion. We conclude that the International Space Station orbit is ideally suited for the purpose of intercalibration.

  9. Prime candidate earth targets for the post-launch radiometric calibration of space-based optical imaging instruments

    USGS Publications Warehouse

    Teillet, P.M.; Barsi, J.A.; Chander, G.; Thome, K.J.

    2007-01-01

    This paper provides a comprehensive list of prime candidate terrestrial targets for consideration as benchmark sites for the post-launch radiometric calibration of space-based instruments. The key characteristics of suitable sites are outlined primarily with respect to selection criteria, spatial uniformity, and temporal stability. The establishment and utilization of such benchmark sites is considered an important element of the radiometric traceability of satellite image data products for use in the accurate monitoring of environmental change.

  10. Field determination of optimal dates for the discrimination of invasive wetland plant species using derivative spectral analysis

    USGS Publications Warehouse

    Laba, M.; Tsai, F.; Ogurcak, D.; Smith, S.; Richmond, M.E.

    2005-01-01

    Mapping invasive plant species in aquatic and terrestrial ecosystems helps to understand the causes of their progression, manage some of their negative consequences, and control them. In recent years, a variety of new remote-sensing techniques, like Derivative Spectral Analysis (DSA) of hyperspectral data, have been developed to facilitate this mapping. A number of questions related to these techniques remain to be addressed. This article attempts to answer one of these questions: Is the application of DSA optimal at certain times of the year? Field radiometric data gathered weekly during the summer of 1999 at selected field sites in upstate New York, populated with purple loosestrife (Lythrum salicaria L.), common reed (Phragmites australis (Cav.)) and cattail (Typha L.) are analyzed using DSA to differentiate among plant community types. First, second and higher-order derivatives of the reflectance spectra of nine field plots, varying in plant composition, are calculated and analyzed in detail to identify spectral ranges in which one or more community types have distinguishing features. On the basis of the occurrence and extent of these spectral ranges, experimental observations suggest that a satisfactory differentiation among community types was feasible on 30 August, when plants experienced characteristic phenological changes (transition from flowers to seed heads). Generally, dates in August appear optimal from the point of view of species differentiability and could be selected for image acquisitions. This observation, as well as the methodology adopted in this article, should provide a firm basis for the acquisition of hyperspectral imagery and for mapping the targeted species over a broad range of spatial scales. ?? 2005 American Society for Photogrammetry and Remote Sensing.

  11. Radiometric Calibration of a Dual-Wavelength, Full-Waveform Terrestrial Lidar.

    PubMed

    Li, Zhan; Jupp, David L B; Strahler, Alan H; Schaaf, Crystal B; Howe, Glenn; Hewawasam, Kuravi; Douglas, Ewan S; Chakrabarti, Supriya; Cook, Timothy A; Paynter, Ian; Saenz, Edward J; Schaefer, Michael

    2016-01-01

    Radiometric calibration of the Dual-Wavelength Echidna(®) Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρapp), a physically-defined value that is related to the radiative and structural characteristics of scanned targets and independent of range and instrument optics and electronics. The errors of ρapp are 8.1% for 1064 nm and 6.4% for 1548 nm. A sensitivity analysis shows that ρapp error is dominated by range errors at near ranges, but by lidar intensity errors at far ranges. Our semi-empirical model for radiometric calibration combines a generalized logistic function to explicitly model telescopic effects due to defocusing of return signals at near range with a negative exponential function to model the fall-off of return intensity with range. Accurate values of ρapp from the radiometric calibration improve the quantification of vegetation structure, facilitate the comparison and coupling of lidar datasets from different instruments, campaigns or wavelengths and advance the utilization of bi- and multi-spectral information added to 3D scans by novel spectral lidars. PMID:26950126

  12. Simultaneous observations of aerosols, clouds, and radiometric fluxes using light-weight autonomous UAVs

    NASA Astrophysics Data System (ADS)

    Roberts, G.; Ramanathan, V.; Corrigan, C.; Ramana, M.; Nguyen, H.

    2006-12-01

    The Maldives Air Campaign (MAC) demonstrated a novel application of stacked autonomous unmanned aerial vehicles (AUAVs) for atmospheric science research; see abstract by Ramanathan et al. in this session. Simultaneous observations from three AUAVs of aerosols, clouds and radiometric fluxes provide insight into aerosol-cloud interactions and subsequent effects on cloud radiative properties. Ground-based measurements of cloud condensation nuclei (CCN) also quantify the cloud-nucleating ability of the boundary layer aerosols. During the experiment, long-range transport of aerosols from the Arabian Peninsula and India was observed and its impact of cloud physical and radiometric properties has been detected. To accomplish this campaign, aerosol, cloud, radiometric instruments, and an integrated data acquisition system have been miniaturized with a total payload weight and power less than 5 kg and 50 W, respectively. The AUAV payloads are mission-specific and outfitted to perform a defined set of measurements depending on the scientific goals. These measurements include aerosol concentration, aerosol size distribution, aerosol absorption, cloud drop concentration and size distribution, solar radiation fluxes (visible and broadband), atmospheric turbulence, temperature, pressure, and relative humidity. The data collected during the MAC campaign has been validated using standard calibration routines in conjunction with comparisons to ground- based instruments in both laboratory and in situ (in aircraft) settings. All instruments have been thoroughly tested and calibrated prior to deployment.

  13. Introduction to the Sentinel-2 radiometric calibration activities during commissioning phase

    NASA Astrophysics Data System (ADS)

    Lachrade, S.; Trmas, T.; Lonjou, V.; Nosavan, J.; Petrucci, B.; Martimort, P.; Isola, C.

    2014-10-01

    In partnership with the European Commission and in the frame of the Copernicus program, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. Sentinel-2 will offer a unique combination of global coverage with a wide field of view (290km), a high revisit (5 days with two satellites), a high spatial resolution (10m, 20m and 60m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains). The first satellite is planned to be launched in mid-2015. In this context, the Centre National d'Etudes Spatiales (CNES) supports ESA to insure the calibration/validation commissioning phase during the first six months in flight. This paper provides first an overview of the Sentinel-2 system and a description of the products delivered by the ground segment associated to the main radiometric specifications to achieve. Then the paper will focus on the description of the Sentinel-2 Technical Expertise Center which is in charge of the radiometric and geometric activities during the commissioning phases of the Sentinel-2 satellites. The paper will finally address the radiometric methods and calibration sites used in this CNES image quality center to reach the specifications of the sensors, in term of absolute calibration, pixel to pixel relative sensitivity, MTF estimation and level 2 products accuracy.

  14. Dating violence and girls in the juvenile justice system.

    PubMed

    Kelly, Patricia J; Cheng, An-Lin; Peralez-Dieckmann, Esther; Martinez, Elisabeth

    2009-09-01

    The purpose of this study is to explore the prevalence and associated behaviors of dating violence among a population of girls in the juvenile justice system. A sample of 590 girls from an urban juvenile justice system completed a questionnaire assessing attitudes and self-efficacy about and occurrence of dating violence. The analysis developed a random effect model to determine a risk profile for dating violence. The strongest predictors of dating violence were (a) initial sexual experience at age 13 or earlier, (b) unwillingness of initial sexual experience, (c) drug use, and (d) low self-efficacy about preventing dating violence. The high prevalence of dating violence and associated behaviors among participants suggests the importance of implementing primary prevention programs to assist preteen girls in delaying initial sexual intercourse and in learning techniques to prevent dating violence. PMID:18768739

  15. New radiometric and petrological constraints on the evolution of the Pichincha volcanic complex (Ecuador)

    NASA Astrophysics Data System (ADS)

    Robin, Claude; Samaniego, Pablo; Le Pennec, Jean-Luc; Fornari, Michel; Mothes, Patricia; van der Plicht, Johannes

    2010-11-01

    Fieldwork, radiometric (40Ar/39Ar and 14C) ages and whole-rock geochemistry allow a reconstruction of eruptive stages at the active, mainly dacitic, Pichincha Volcanic Complex (PVC), whose eruptions have repeatedly threatened Quito, most recently from 1999 to 2001. After the emplacement of basal lavas dated at 1100 to 900 ka, the eruptive activity of the old Rucu Pichincha volcano lasted from 850 ka to 150 ka before present (BP) and resulted in a 15 20 km-wide edifice, which comprises three main building stages: (1) A lower stratocone (Lower Rucu, 160 km3 in volume) developed from 850 to 600 ka; (2) This edifice was capped by a steeper-sided and less voluminous cone (the Upper Rucu, 40-50 km3), the history of which started 450-430 ka ago and ended around 250 ka with a sector collapse; (3) A smaller (8-10 km3) but more explosive edifice grew in the avalanche amphitheatre and ended Rucu Pichincha's history about 150 ka ago. The Guagua Pichincha volcano (GGP) was developed from 60 ka on the western flank of Rucu with four growth stages separated by major catastrophic events. (1) From 60 to 47 ka, a basal effusive stratocone developed, terminating with a large ash-and-pumice flow event. (2) This basal volcano was followed by a long-lasting dome building stage and related explosive episodes, the latter occurring between 28-30 and 22-23 ka. These first two stages formed the main GGP (30 km3), a large part of which was removed by a major collapse 11 ka BP. (3) Sustained explosive activity and viscous lava extrusions gave rise to a new edifice, Toaza (4-5 km3 in volume), which in turn collapsed around 4 ka BP. (4) The ensuing amphitheatre was partly filled by the 1-km3 Cristal dome, which is the historically active centre of the Pichincha complex. The average output rate for the whole PVC is 0.29 km3/ka. Nevertheless, the chronostratigraphic resolution we obtained for Lower Rucu Pichincha and for the two main edifices of Guagua Pichincha (main GGP and Toaza), leads to eruptive rates of 0.60-0.65 km3/ka during these construction stages. These output rates are compared to those of other mainly dacitic volcanoes from continental arcs. Our study also supports an overall SiO2 and large-ion lithophile elements enrichment as the PVC develops. In particular, distinctive geochemical signatures indicate the involvement of a new magma batch at the transition between Rucu and Guagua. At the GGP, the same phenomenon occurs at each major collapse event marking the onset of the ensuing magmatic stage. Since the 11-ka-BP collapse event, this magmatic behaviour has led to increasingly explosive activity. Four explosive cycles of between 100 and 200 years long have taken place at the Cristal dome in the past 3.7 ka, and repose intervals between these cycles have tended to decrease with time. As a consequence, we suggest that the 1999-2001 eruptive period may have initiated a new eruptive cycle that might pose a future hazard to Quito (2 million inhabitants).

  16. Date Attachable Offline Electronic Cash Scheme

    PubMed Central

    Sun, Wei-Zhe; Hau, Hoi-Tung

    2014-01-01

    Electronic cash (e-cash) is definitely one of the most popular research topics in the e-commerce field. It is very important that e-cash be able to hold the anonymity and accuracy in order to preserve the privacy and rights of customers. There are two types of e-cash in general, which are online e-cash and offline e-cash. Both systems have their own pros and cons and they can be used to construct various applications. In this paper, we pioneer to propose a provably secure and efficient offline e-cash scheme with date attachability based on the blind signature technique, where expiration date and deposit date can be embedded in an e-cash simultaneously. With the help of expiration date, the bank can manage the huge database much more easily against unlimited growth, and the deposit date cannot be forged so that users are able to calculate the amount of interests they can receive in the future correctly. Furthermore, we offer security analysis and formal proofs for all essential properties of offline e-cash, which are anonymity control, unforgeability, conditional-traceability, and no-swindling. PMID:24982931

  17. Date attachable offline electronic cash scheme.

    PubMed

    Fan, Chun-I; Sun, Wei-Zhe; Hau, Hoi-Tung

    2014-01-01

    Electronic cash (e-cash) is definitely one of the most popular research topics in the e-commerce field. It is very important that e-cash be able to hold the anonymity and accuracy in order to preserve the privacy and rights of customers. There are two types of e-cash in general, which are online e-cash and offline e-cash. Both systems have their own pros and cons and they can be used to construct various applications. In this paper, we pioneer to propose a provably secure and efficient offline e-cash scheme with date attachability based on the blind signature technique, where expiration date and deposit date can be embedded in an e-cash simultaneously. With the help of expiration date, the bank can manage the huge database much more easily against unlimited growth, and the deposit date cannot be forged so that users are able to calculate the amount of interests they can receive in the future correctly. Furthermore, we offer security analysis and formal proofs for all essential properties of offline e-cash, which are anonymity control, unforgeability, conditional-traceability, and no-swindling. PMID:24982931

  18. Reduced major axis approach for correcting GPM/GMI radiometric biases to coincide with radiative transfer simulation

    NASA Astrophysics Data System (ADS)

    Islam, Tanvir; Srivastava, Prashant K.; Petropoulos, George P.; Singh, Sudhir K.

    2016-01-01

    Correcting radiometric biases is crucial prior to the use of satellite observations in a physically based retrieval or data assimilation system. This study proposes an algorithm - RARMA (Radiometric Adjustment using Reduced Major Axis) for correcting the radiometric biases so that the observed radiances coincide with the simulation of a radiative transfer model. The RARMA algorithm is a static bias correction algorithm, which is developed using the reduced major axis (RMA) regression approach. NOAA's Community Radiative Transfer Model (CRTM) has been used as the basis of radiative transfer simulation for adjusting the observed radiometric biases. The algorithm is experimented and applied to the recently launched Global Precipitation Measurement (GPM) mission's GPM Microwave Imager (GMI). Experimental results demonstrate that radiometric biases are apparent in the GMI instrument. The RARMA algorithm has been able to correct such radiometric biases and a significant reduction of observation residuals is revealed while assessing the performance of the algorithm. The experiment is currently tested on clear scenes and over the ocean surface, where, surface emissivity is relatively easier to model, with the help of a microwave emissivity model (FASTEM-5).

  19. Laser photothermal radiometric instrumentation for fast in-line industrial steel hardness inspection and case depth measurements.

    PubMed

    Guo, Xinxin; Sivagurunathan, Konesh; Garcia, Jose; Mandelis, Andreas; Giunta, Salvatore; Milletari, Salvatore

    2009-03-01

    A contact-free, nondestructive laser photothermal radiometric instrumentation technique was developed to meet industrial demand for on-line steel hardness inspection and quality control. A series of industrial steel samples, flat or curvilinear, with different effective hardness case depths ranging between 0.21 and 1.78 mm were measured. The results demonstrated that three measurement parameters (metrics) extracted from fast swept-sine photothermal excitation and measurements, namely, the phase minimum frequency f(min), the peak or trough frequency width W, and the area S, are complementary for evaluating widely different ranges of hardness case depth: f(min) is most suitable for large case depths, and W and S for small case depths. It was also found that laser beam angular inclination with respect to the surface plane of the sample strongly affects hardness measurement resolution and that the phase frequency maximum is more reliable than the amplitude maximum for laser beam focusing on the sample surface. PMID:19252602

  20. A Low Loss Microstrip Antenna for Radiometric Applications

    NASA Technical Reports Server (NTRS)

    Wahid, Parveen

    2000-01-01

    The design and analysis of a series-fed, low-loss, inverted microstrip array antenna, operating at 1.413 GHz is presented. The antenna is composed of two subarrays. Each subarray consists of an equal number of microstrip patches all connected together with microstrip lines. In the first design microstrip array for linear polarization is presented which incorporated a series feeding technique. The next design, which is capable of dual linear polarization (V-polarization and H-polarization), utilizes a corporate feed network for the V-pol and series feed arrangement for the H-pol. The first element of each subarray for H-pol is coaxially fed with a 180 deg phase difference. This approach ensures a symmetric radiation pattern on broadside in H-pol. For the V-pol two feeds are in the same phase on the two subarrays ensuring a broadside beam in V-pol. The designs presented here are simulated using the IE3D code that utilizes the method of moments. Measured results are compared with simulated results and show good agreement.

  1. The 60 GHz radiometric local vertical sensor experiment

    NASA Technical Reports Server (NTRS)

    Grauling, C. H., Jr.

    1973-01-01

    The experiment concept involves the use of millimeter wave radiation the atmospheric oxygen to provide vertical sensing information to a satellite-borne radiometer. The radiance profile studies require the calculation of ray brightness temperature as a function of tangential altitude and atmosphere model, and the computer program developed for this purpose is discussed. Detailed calculations have been made for a total of 12 atmosphere models, including some showing severe warning conditions. The experiment system analysis investigates the effect of various design choices on system behavior. Calculated temperature profiles are presented for a wide variety of frequencies, bandwidths, and atmosphere models. System performance is determined by the convolution of the brightness temperature and an assumed antenna pattern. A compensation scheme to account for different plateau temperatures is developed and demonstrated. The millimeter wave components developed for the local vertical sensor are discussed, with emphasis on the antenna, low noise mixer, and solid state local oscillator. It was concluded that a viable sensing technique exists, useful over a wide range of altitude with an accuracy generally on the order of 0.01 degree or better.

  2. Radiometric analysis and radiological hazards of Chinese commercial marble

    NASA Astrophysics Data System (ADS)

    Lu, Xinwei

    The activity concentrations of 226Ra, 232Th and 40K in commercial marble materials have been determined using a NaI(Tl) ?-ray spectrometer with a matrix-inversion-based spectral stripping technique. Knowledge of radioactivity present in marble materials enables one to assess any possible radiological risks to human health. The concentrations of 226Ra, 232Th and 40K in Chinese commercial marble range from 8.4 to 157.4, 5.6 to 165.5 and 44.1 to 1352.7 Bq kg-1, respectively. The natural radionuclide concentration varied with color and production site of commercial marble. The activity concentrations of 226Ra, 232Th and 40K in white, gray, black, green and yellow marble samples are comparatively smaller than those in brown and red marble samples. The radium equivalent activity (Raeq), the external hazard index (Hex), the internal hazard index (Hin) and the annual gonadal dose equivalent were also calculated and compared with the internationally recommended values. One type of brown commercial marble (TSB) of China does not satisfy the universal standards.

  3. Sexual Coercion on Dates: It's Not Just Rape.

    ERIC Educational Resources Information Center

    Waldner-Haugrud, Lisa

    1995-01-01

    Contends that sexual coercion while dating falls under the umbrella of school-related violence. Discusses acquaintance and date rape, a sexual coercion continuum, and coercion victims. Concludes with a discussion of six techniques to reduce risk of sexual coercion. (CFR)

  4. Radiocarbon Dating, Memories, and Hopes

    DOE R&D Accomplishments Database

    Libby, W. F.

    1972-10-01

    The history of radiocarbon dating from 1939 to the present is reviewed. The basic principles of radiocarbon dating are that cosmic rays make living things radioactive with {sup 14}C to a certain level fixed by the environment and that at death the intake of food stops so no replenishment of the {sup 14}C steadily lost by the immutable decay occurs. Therefore measurement of the degree of decay gives the time lapse since death, i.e., the radiocarbon age. The equipment developed and experiments performed to measure the specific activity of specimens to be dated are described. The results obtained by world-wide experimenters are discussed. These showed that on simultaneity radiocarbon dating is apparently reliable but that absolute dates may be incorrect by as much as 600 to 700 y. The value of radiocarbon dating to archaeologists, geologists, climatologists, and historians is stressed. (LCL)

  5. Landsat-8 Thermal Infrared Sensor (TIRS) Vicarious Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Barsi, Julia A.; Shott, John R.; Raqueno, Nina G.; Markham, Brian L.; Radocinski, Robert G.

    2014-01-01

    Launched in February 2013, the Landsat-8 carries on-board the Thermal Infrared Sensor (TIRS), a two-band thermal pushbroom imager, to maintain the thermal imaging capability of the Landsat program. The TIRS bands are centered at roughly 10.9 and 12 micrometers (Bands 10 and 11 respectively). They have 100 m spatial resolution and image coincidently with the Operational Land Imager (OLI), also on-board Landsat-8. The TIRS instrument has an internal calibration system consisting of a variable temperature blackbody and a special viewport with which it can see deep space; a two point calibration can be performed twice an orbit. Immediately after launch, a rigorous vicarious calibration program was started to validate the absolute calibration of the system. The two vicarious calibration teams, NASA/Jet Propulsion Laboratory (JPL) and the Rochester Institute of Technology (RIT), both make use of buoys deployed on large water bodies as the primary monitoring technique. RIT took advantage of cross-calibration opportunity soon after launch when Landsat-8 and Landsat-7 were imaging the same targets within a few minutes of each other to perform a validation of the absolute calibration. Terra MODIS is also being used for regular monitoring of the TIRS absolute calibration. The buoy initial results showed a large error in both bands, 0.29 and 0.51 W/sq m·sr·micrometers or -2.1 K and -4.4 K at 300 K in Band 10 and 11 respectively, where TIRS data was too hot. A calibration update was recommended for both bands to correct for a bias error and was implemented on 3 February 2014 in the USGS/EROS processing system, but the residual variability is still larger than desired for both bands (0.12 and 0.2 W/sq m·sr·micrometers or 0.87 and 1.67 K at 300 K). Additional work has uncovered the source of the calibration error: out-of-field stray light. While analysis continues to characterize the stray light contribution, the vicarious calibration work proceeds. The additional data have not changed the statistical assessment but indicate that the correction (particularly in band 11) is probably only valid for a subset of data. While the stray light effect is small enough in Band 10 to make the data useful across a wide array of applications, the effect in Band 11 is larger and the vicarious results suggest that Band 11 data should not be used where absolute calibration is required.

  6. Color image processing for date quality evaluation

    NASA Astrophysics Data System (ADS)

    Lee, Dah Jye; Archibald, James K.

    2010-01-01

    Many agricultural non-contact visual inspection applications use color image processing techniques because color is often a good indicator of product quality. Color evaluation is an essential step in the processing and inventory control of fruits and vegetables that directly affects profitability. Most color spaces such as RGB and HSV represent colors with three-dimensional data, which makes using color image processing a challenging task. Since most agricultural applications only require analysis on a predefined set or range of colors, mapping these relevant colors to a small number of indexes allows simple and efficient color image processing for quality evaluation. This paper presents a simple but efficient color mapping and image processing technique that is designed specifically for real-time quality evaluation of Medjool dates. In contrast with more complex color image processing techniques, the proposed color mapping method makes it easy for a human operator to specify and adjust color-preference settings for different color groups representing distinct quality levels. Using this color mapping technique, the color image is first converted to a color map that has one color index represents a color value for each pixel. Fruit maturity level is evaluated based on these color indices. A skin lamination threshold is then determined based on the fruit surface characteristics. This adaptive threshold is used to detect delaminated fruit skin and hence determine the fruit quality. The performance of this robust color grading technique has been used for real-time Medjool date grading.

  7. VIEW OF DATE DRIVE, SHOWING DATE PALMS. NOTE TRELLIS ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF DATE DRIVE, SHOWING DATE PALMS. NOTE TRELLIS ON TYPE 11 FACILITY, FACILITY 808. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  8. Performance in a Social Context: Date Rape versus Date Right.

    ERIC Educational Resources Information Center

    Mann, Cynthia A.; And Others

    1989-01-01

    Examines the performance of texts ("trigger scripting") as a method of modifying sexual attitudes and assertiveness in a dating context in order to prevent date rape or unwanted sexual aggression. Suggests that live performance alone and live performance plus discussion cam modify sexual attitudes and increase awareness of the issues. (MM)

  9. Scene correction (precision techniques) of ERTS sensor data using digital image processing techniques

    NASA Technical Reports Server (NTRS)

    Bernstein, R.

    1974-01-01

    Techniques have been developed, implemented, and evaluated to process ERTS Return Beam Vidicon (RBV) and Multispectral Scanner (MSS) sensor data using digital image processing techniques. The RBV radiometry has been corrected to remove shading effects, and the MSS geometry and radiometry have been corrected to remove internal and external radiometric and geometric errors. The results achieved show that geometric mapping accuracy of about one picture element RMS and two picture elements (maximum) can be achieved by the use of nine ground control points. Radiometric correction of MSS and RBV sensor data has been performed to eliminate striping and shading effects to about one count accuracy. Image processing times on general purpose computers of the IBM 370/145 to 168 class are in the range of 29 to 3.2 minutes per MSS scene (4 bands). Photographic images of the fully corrected and annotated scenes have been generated from the processed data and have demonstrated excellent quality and information extraction potential.

  10. Investigating the influence of radiometric calibration on tree species determination based on small footprint full-waveform airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Mücke, W.; Briese, C.; Hollaus, M.; Pfeifer, N.; Wagner, W.

    2013-12-01

    Small footprint airborne LiDAR is a well-established measurement technique in forestry, where cost- and time efficient wide-area data acquisition of the vegetation structure is required. Gathering stand-based information about tree species composition is of particular interest for forestry applications. Modern LiDAR systems provide, next to the acquired 3D (i.e. geometric) information, also a quantification of the signal strength of each echo. In order to utilize this information for tree species determination independently from different overlapping LiDAR swaths, different LiDAR sensors or acquisition times, radiometric calibration is a necessity. This contribution summarises the theoretical background of radiometric LiDAR data calibration on the physical basis of the radar equation. Using LiDAR observations of reference targets with known reflectivity the so-called calibration constant is computed. It accounts for sensor specific parameters, as well as atmospheric attenuation of the laser signal. Hence the backscatter properties of the laser echoes can be determined and physical observables characterizing the reflectivity of the scanned surface can be estimated. A practical calibration workflow is demonstrated on the example of a single wavelength full-waveform LiDAR data set from a mixed woodland in Austria. Subsequently, an automated method for tree species determination that is based on the laser light scattering mechanisms in the forest canopy is applied on both (calibrated and un-calibrated) data sets. First, an edge-based segmentation approach is used to aggregate LiDAR echoes to segments representing single tree crowns. Second, metrics are computed for each tree crown describing radiometric and geometric features that are related to foliage composition. Third, these metrics are used in a knowledge-based fuzzy classification scheme for the determination of segments representing coniferous and deciduous trees. Influences of the radiometric calibration on the classification results are shown and discussed through a comparison of adjacent swaths with focus on the overlapping areas, as well as the whole study site, before and after calibration. An extensive set of forestry inventory data including information on tree height, diameter, crown height and species, is used to evaluate the quality of the different classification results with and without usage of calibrated data. We demonstrate that radiometric calibration of airborne LiDAR data produces highly homogeneous data sets throughout and across adjacent swaths. The calibrated data are rich in contrast and, on the one hand, a valuable source for visual interpretation. On the other hand, (un-) supervised classification schemes benefit from the calibrated data in terms of higher robustness in depiction of diverse tree species. It is shown that calibrated full-waveform LiDAR data are a most suitable basis for vegetation classification of large areas, with a large number of acquisition swaths and high relief energy.

  11. Radiocarbon Dating: An Annotated Bibliography.

    ERIC Educational Resources Information Center

    Fortine, Suellen

    This selective annotated bibliography covers various sources of information on the radiocarbon dating method, including journal articles, conference proceedings, and reports, reflecting the most important and useful sources of the last 25 years. The bibliography is divided into five parts--general background on radiocarbon, radiocarbon dating,

  12. National Date Palm Germplasm Repository

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Clonal Germplasm Repository for Citrus & Dates (NCGRCD), located in Riverside, California USA, is a project of the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA). The NCGRCD maintains a collection of germplasm of date palm (Phoneix dactylifera ...

  13. Childhood Maltreatment and Date Rape.

    ERIC Educational Resources Information Center

    Sanders, Barbara; Moore, Dina L.

    1999-01-01

    Study compares women college students who reported unwanted sexual experiences judged to constitute date rape with controls who reported no rape. Findings suggest that compared to controls, date-rape group had significantly higher scores on measures of overall childhood stress. Concludes that early forms of maltreatment (not specifically sexual)

  14. Hydration rind dates rhyolite flows.

    PubMed

    Friedman, I

    1968-02-23

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago. PMID:17768978

  15. Hydration rind dates rhyolite flows

    USGS Publications Warehouse

    Friedman, I.

    1968-01-01

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  16. Ar-Ar Dating of Martian Meteorite, Dhofar 378: An Early Shock Event?

    NASA Technical Reports Server (NTRS)

    Park, J.; Bogard, D. D.

    2006-01-01

    Martian meteorite, Dhofar 378 (Dho378) is a basaltic shergottite from Oman, weighing 15 g, and possessing a black fusion crust. Chemical similarities between Dho378 and the Los Angeles 001 shergottite suggests that they might have derived from the same Mars locale. The plagioclase in other shergottites has been converted to maskelenite by shock, but Dho378 apparently experienced even more intense shock heating, estimated at 55-75 GPa. Dho378 feldspar (approximately 43 modal %) melted, partially flowed and vesiculated, and then partially recrystallized. Areas of feldspathic glass are appreciably enriched in K, whereas individual plagioclases show a range in the Or/An ratio of approximately 0.18-0.017. Radiometric dating of martian shergottites indicate variable formation times of 160-475 Myr, whereas cosmic ray exposure (CRE) ages of shergottites indicate most were ejected from Mars within the past few Myr. Most determined Ar-39-Ar-40 ages of shergottites appear older than other radiometric ages because of the presence of large amounts of martian atmosphere or interior Ar-40. Among all types of meteorites and returned lunar rocks, the impact event that initiated the CRE age very rarely reset the Ar-Ar age. This is because a minimum time and temperature is required to facilitate Ar diffusion loss. It is generally assumed that the shock-texture characteristics in martian meteorites were produced by the impact events that ejected the rocks from Mars, although the time of these shock events (as opposed to CRE ages) are not directly dated. Here we report Ar-39-Ar-40 dating of Dho378 plagioclase. We suggest that the determined age dates the intense shock heating event this meteorite experienced, but that it was not the impact that initiated the CRE age.

  17. MSFIA-LOV system for (226)Ra isolation and pre-concentration from water samples previous radiometric detection.

    PubMed

    Rodríguez, Rogelio; Borràs, Antoni; Leal, Luz; Cerdà, Víctor; Ferrer, Laura

    2016-03-10

    An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of (226)Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO2 and the BaSO4 co-precipitation, achieving more selectivity especially in water samples with low radium levels. Radium is adsorbed on MnO2 deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO2 to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO4. The (226)Ra can be directly detected in off-line mode using a low background proportional counter (LBPC) or through a liquid scintillation counter (LSC), after performing an on-line coprecipitate dissolution. Thus, the versatility of the proposed system allows the selection of the radiometric detection technique depending on the detector availability or the required response efficiency (sample number vs. response time and limit of detection). The MSFIA-LOV system improves the precision (1.7% RSD), and the extraction frequency (up to 3 h(-1)). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The (226)Ra minimum detectable activities (LSC: 0.004 Bq L(-1); LBPC: 0.02 Bq L(-1)) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC. PMID:26893088

  18. The maximum likelihood dating of magnetostratigraphic sections

    NASA Astrophysics Data System (ADS)

    Man, Otakar

    2011-04-01

    In general, stratigraphic sections are dated by biostratigraphy and magnetic polarity stratigraphy (MPS) is subsequently used to improve the dating of specific section horizons or to correlate these horizons in different sections of similar age. This paper shows, however, that the identification of a record of a sufficient number of geomagnetic polarity reversals against a reference scale often does not require any complementary information. The deposition and possible subsequent erosion of the section is herein regarded as a stochastic process, whose discrete time increments are independent and normally distributed. This model enables the expression of the time dependence of the magnetic record of section increments in terms of probability. To date samples bracketing the geomagnetic polarity reversal horizons, their levels are combined with various sequences of successive polarity reversals drawn from the reference scale. Each particular combination gives rise to specific constraints on the unknown ages of the primary remanent magnetization of samples. The problem is solved by the constrained maximization of the likelihood function with respect to these ages and parameters of the model, and by subsequent maximization of this function over the set of possible combinations. A statistical test of the significance of this solution is given. The application of this algorithm to various published magnetostratigraphic sections that included nine or more polarity reversals gave satisfactory results. This possible self-sufficiency makes MPS less dependent on other dating techniques.

  19. A Comparison of Rapid-Screen 14C Dates and U/Th Dates from Fossil Corals: Implications for Paleoclimate Reconstruction

    NASA Astrophysics Data System (ADS)

    Grothe, P. R.; Cobb, K. M.; Bush, S.; Cheng, H.; Santos, G.; Southon, J. R.; Edwards, R. L.

    2014-12-01

    Paleoclimate records from fossil corals provide valuable benchmarks for climate model simulations of tropical climate variability. Unfortunately, the number of such reconstructions is limited by the rarity of the relatively large fossil coral heads that are targeted for paleoclimate studies. Abundant, albeit shorter (5-10yrs-long) fossil coral sequences could be used to generate a more robust, quasi-continuous reconstruction of tropical climate with built-in uncertainty estimates, but the large number of radiometric dates required is costly. A new rapid-screen 14C dating method, with a nominal precision of 1.8% (1?) for young carbonates (Bush et al., 2013), is roughly 10 times faster than high-precision U/Th dating, making it well-suited to screening a large number of corals. In this study, we compare rapid-screen 14C dates to both high-precision 14C dates and U/Th dates from well-characterized mid- to late-Holocene fossil corals collected from Christmas and Fanning Islands (2-4N, 157-160W) (Cobb et al., 2013). Our results show that most rapid-screen 14C dates agree with high-precision 14C dates (N=3) and U/Th dates (N=42), within combined uncertainties. However, two samples that contain 15 and 23% calcite (as determined by XRD) are associated with large discrepancies in calibrated 14C vs published U/Th ages (5065-5579 yBP (2?) versus 6350 13 yBP (2?) and 4868-5424 yBP (2?) vs 6598 13 yBP (2?)), respectively (Cobb et al., 2013). The 14C-U/Th mismatches, as well as poor reproducibility of replicate U/Th dates from these samples, are consistent with diagenetic alteration indicated by the presence of calcite. Mass balance calculations indicate that the dating discrepancies can be explained by a combination of 14C addition and U removal, both of which can occur through calcite recrystallization during freshwater diagenesis. Results illustrate that the rapid-screen 14C dating method is well-suited to surveying a large number (~100's) of fossil coral samples, provided that samples are pre-screened for calcite. Beyond that, concordance between paired 14C and U/Th dates provides valuable confirmation of closed-system behavior and chronological accuracy.

  20. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band

    NASA Technical Reports Server (NTRS)

    Flittner, D. E.; Herman, B. M.; Thome, K. J.; Simpson, J. M.; Reagan, J. A.

    1993-01-01

    A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15 percent. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimated total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands.

  1. OCRA radiometric cloud fractions for GOME-2 on MetOp-A/B

    NASA Astrophysics Data System (ADS)

    Lutz, R.; Loyola, D.; Gimeno Garca, S.; Romahn, F.

    2015-12-01

    This paper describes an approach for cloud parameter retrieval (radiometric cloud fraction estimation) using the polarization measurements of the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the MetOp-A/B satellites. The core component of the Optical Cloud Recognition Algorithm (OCRA) is the calculation of monthly cloud-free reflectances for a global grid (resolution of 0.2 in longitude and 0.2 in latitude) and to derive radiometric cloud fractions. These cloud fractions will serve as a priori information for the retrieval of cloud top height (CTH), cloud top pressure (CTP), cloud top albedo (CTA) and cloud optical thickness (COT) with the Retrieval Of Cloud Information using Neural Networks (ROCINN) algorithm. This approach is already being implemented operationally for the GOME/ERS-2 and SCIAMACHY/ENVISAT sensors and here we present version 3.0 of the OCRA algorithm applied to the GOME-2 sensors. Based on more than six years of GOME-2A data (February 2007-June 2013), reflectances are calculated for ? 35 000 orbits. For each measurement a degradation correction as well as a viewing angle dependent and latitude dependent correction is applied. In addition, an empirical correction scheme is introduced in order to remove the effect of oceanic sun glint. A comparison of the GOME-2A/B OCRA cloud fractions with co-located AVHRR geometrical cloud fractions shows a general good agreement with a mean difference of -0.150.20. From operational point of view, an advantage of the OCRA algorithm is its extremely fast computational time and its straightforward transferability to similar sensors like OMI (Ozone Monitoring Instrument), TROPOMI (TROPOspheric Monitoring Instrument) on Sentinel 5 Precursor, as well as Sentinel 4 and Sentinel 5. In conclusion, it is shown that a robust, accurate and fast radiometric cloud fraction estimation for GOME-2 can be achieved with OCRA by using the polarization measurement devices (PMDs).

  2. Radiometric uncertainty per pixel for the Sentinel-2 L1C products

    NASA Astrophysics Data System (ADS)

    Gorroño, Javier; Gascon, Ferran; Fox, Nigel P.

    2015-10-01

    In the framework of the European Union Copernicus programme, the European Space Agency (ESA) has launched the Sentinel-2 (S2) Earth Observation (EO) mission which provides optical high spatial resolution imagery. Here is presented a tool, S2-RUT, (Sentinel-2 Radiometric Uncertainty Tool) allowing estimation of the radiometric uncertainties associated to each pixel using as input the top-of-atmosphere (TOA) reflectance images provided by ESA. The Sentinel-2 radiometric analysis focuses on the review of the pre- and post-launch characterisations in order to specify the uncertainty contributors at a pixel level and allow changes to be proposed in the uncertainty contributors where necessary. The identified uncertainty contributors are combined using a metrological Guide to Expression of Uncertainty in Measurement' (GUM) model that is validated by comparing the results to a multivariate Monte Carlo Method (MCM). Specific contributors of the TOA reflectance are initially characterised and its future integration in the tool is discussed. The software implementation of the S2-RUT tool relies on the flexibility of the JPEG2000 standard using partial decoding. Auxiliary information for the uncertainty calculation is extracted from the metadata and quality masks integrated in the L1C product. In addition, using the detector footprint mask it is possible to account for parameters dependent on the neighbouring pixels and/or detector module. The L1C uncertainty is coded using 1 byte with an extra optional byte for complementary information. The resulting images and the metadata are directly appended to the original L1C product.

  3. Storm-Associated Microwave Radiometric Signatures in the Frequency Range of 90-220 GHz

    NASA Technical Reports Server (NTRS)

    Wang, James R.; Zhan, J.; Racette, P.

    1997-01-01

    Radiometric measurements were made by a millimeter-wave imaging radiometer (MIR) at the frequencies of 89, 150, 183.3 +/- 1, 183.3 +/- 3, 183.3 +/- 7, and 220 GHz aboard the NASA ER-2 aircraft at an altitude of about 20 km over two rainstorms: one in the western Pacific Ocean on 19 January 1993 and another in southern Florida on 5 October 1993. These measurements were complemented by nearly simultaneous observations by other sensors aboard the same aircraft and another aircraft flying along the same path. Analysis of data from these measurements, aided by radiative transfer and radar reflectivity calculations of hydrometeor profiles, which arc generated by a general cloud ensemble model, demonstrates the utility of these frequencies for studying the structure of frozen hydrometeors associated with storms. Particular emphasis is placed on the three water vapor channels near 183.3 GHz. Results show that the radiometric signatures measured by these channels over the storm-associated scattering media bear a certain resemblance to those previously observed over a clear and fairly dry atmosphere with a cold ocean background. Both of these atmospheric conditions are characterized by a small amount of water vapor above a cold background. Radiative transfer calculations were made at these water vapor channels for a number of relative humidity profiles characterizing dry atmospheres over an ocean surface. The results are compared with the measurements to infer some characteristics of the environment near the scattering media. Furthermore, radiometric signatures from these channels display unique features for towering deep convective cells that could be used to identify the presence of such cells in storms.

  4. A novel solution for car traffic control based on radiometric microwave devices

    NASA Astrophysics Data System (ADS)

    Soldovieri, Francesco; Denisov, Alexander; Speziale, Victor

    2014-05-01

    The significant problem of traffic in big cities, connected with huge and building up quantity of automobile cars, demands for novel strategies, based on nonconventional solutions, in order to improve system traffic control, especially at crossroads. As well known, the usual solution is based on the time relay, which requires the installation of a fixed traffic interval (signal light switching) at a crossroad; this solution is low cost, but does not account for the actual traffic conditions. Therefore, in the recent years, attention is towards to new designs, where the monitoring of the and control of traffic is carried out by using various methods including, optical, the infrared, magnetic, radar tracking, acoustical ones. In this work, we discuss the deployment of high sensitivity radiometric systems and radiometers(sensor) in the microwave range [1, 2]. In fact, the radiometer as "sensor" can provide an always updated information about the car traffic in any weather condition and in absence or low visibility conditions. In fact, the radiometric sensor detects the cars thanks to the different behavior of the car roofs which reflect the cold sky whereas the road asphalt is visible as warm object (at around outside temperature). [1] A. G. Denisov, V. P. Gorishnyak, S. E. Kuzmin et al., "Some experiments concerning resolution of 32 sensors passive 8mm wave imaging system," in Proceedings of the International Symposium on Space Terahertz Technology (ISSTT '09), Charlottesville, Va, USA, April 2009. [2] F. Soldovieri, A. Natale, V. Gorishnyak, A. Pavluchenko, A. Denisov, and L. Chen, "Radiometric Imaging for Monitoring and Surveillance Issues," International Journal of Antennas and Propagation, vol. 2013, Article ID 272561, 8 pages, 2013. doi:10.1155/2013/272561.

  5. L5 TM radiometric recalibration procedure using the internal calibration trends from the NLAPS trending database

    NASA Astrophysics Data System (ADS)

    Chander, Gyanesh; Haque, Md. Obaidul; Micijevic, Esad; Barsi, Julia A.

    2008-08-01

    From the Landsat program's inception in 1972 to the present, the earth science user community has benefited from a historical record of remotely sensed data. The multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone for this extensive archive. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset for each detector. The IC system degraded with time causing radiometric calibration errors up to 20 percent. In May 2003 the National Landsat Archive Production System (NLAPS) was updated to use a gain model rather than the scene acquisition specific IC gains to calibrate TM data processed in the United States. Further modification of the gain model was performed in 2007. L5 TM data that were processed using IC prior to the calibration update do not benefit from the recent calibration revisions. A procedure has been developed to give users the ability to recalibrate their existing Level-1 products. The best recalibration results are obtained if the work order report that was originally included in the standard data product delivery is available. However, many users may not have the original work order report. In such cases, the IC gain look-up table that was generated using the radiometric gain trends recorded in the NLAPS database can be used for recalibration. This paper discusses the procedure to recalibrate L5 TM data when the work order report originally used in processing is not available. A companion paper discusses the generation of the NLAPS IC gain and bias look-up tables required to perform the recalibration.

  6. Three Years of Atmospheric Infrared Sounder Radiometric Calibration Validation using Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.; Broberg, Steve; Elliott, Denis; Gaiser, Steve; Gregorich, Dave

    2006-01-01

    This paper evaluates the absolute accuracy and stability of the radiometric calibration of the Atmospheric Infrared Sounder (AIRS) by analyzing the difference between the brightness temperatures measured at 2616 cm(exp -1) and those calculated at the top of the atmosphere (TOA), using the Real-Time Global Sea Surface Temperature (RTGSST) for cloud-free night tropical oceans between +/- 30 degrees latitude. The TOA correction is based on radiative transfer. The analysis of the first 3 years of AIRS radiances verifies the absolute calibration at 2616 cm(exp -1) to better than 200 mK, with better than 16 mK/yr stability. The AIRS radiometric calibration uses an internal full aperture wedge blackbody with the National Institute of Standards and Technology (NIST) traceable prelaunch calibration coefficients. The calibration coefficients have been unchanged since launch. The analysis uses very tight cloud filtering, which selects about 7000 cloud-free tropical ocean spectra per day, about 0.5% of the data. The absolute accuracy and stability of the radiometry demonstrated at 2616 cm(sup -1) are direct consequences of the implementation of AIRS as a thermally controlled, cooled grating-array spectrometer and meticulous attention to details. Comparable radiometric performance is inferred from the AIRS design for all 2378 channels. AIRS performance sets the benchmark for what can be achieved with a state-of-the-art hyperspectral radiometer from polar orbit and what is expected from future hyperspectral sounders. AIRS was launched into a 705 km altitude polar orbit on NASA's Earth Observation System (EOS) Aqua spacecraft on 4 May 2002. AIRS covers the 3.7-15.4 micron region of the thermal infrared spectrum with a spectral resolution of nu/Delta nu = 1200 and has returned 3.7 million spectra of the upwelling radiance each day since the start of routine data gathering in September 2002.

  7. Whitecap lifetime stages from infrared imagery with implications for microwave radiometric measurements of whitecap fraction

    NASA Astrophysics Data System (ADS)

    Potter, Henry; Smith, Geoffrey B.; Snow, Charlotte M.; Dowgiallo, David J.; Bobak, Justin P.; Anguelova, Magdalena D.

    2015-11-01

    Quantifying active and residual whitecap fractions separately can improve parameterizations of air-sea fluxes associated with breaking waves. We use data from a multi-instrumental field campaign on Floating Instrument Platform (FLIP) to simultaneously capture the signatures of active and residual whitecaps at visible, infrared (IR), and microwave wavelengths using, respectively, video camera, mid-IR camera, and a radiometer at 10 GHz. We present results from processing and analyzing IR images and correlating this information with radiometric time series of brightness temperature at horizontal and vertical polarizations TBH and TBV. The results provide evidence that breaking crests and decaying foam appear in mid-IR as bright and dark pixels clearly distinguishing active from residual whitecaps. We quantify the durations of whitecap lifetime stages from the IR images and identify their corresponding signatures in TB time series. Results show that TBH and TBV vary in phase during the active and in antiphase during the residual whitecap stages. A methodology to distinguish active and residual whitecaps in radiometric time series without a priori IR information has been developed and verified with corresponding IR and video images. The method uses the degree of polarization P (the ratio between the sum and difference of TBV and TBH) to capture whitecaps as prominent spikes. The maximum and zero-crossing of the first derivative of P serve to identify the presence of active whitecaps, while the minimum of dP marks the transition from active to residual whitecap stage. The findings have implications for radiometric measurements of active and total whitecap fractions.

  8. Segmentation of Heritage Building by Means of Geometric and Radiometric Components from Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Aitelkadi, K.; Tahiri, D.; Simonetto, E.; Sebari, I.; Polidori, L.

    2013-07-01

    Nowadays, the terrestrial laser scanning represents an integral source of data for cultural heritage 3D storage and access through digital communication tools. The achievement of 3D models requires the implementation of several tasks such as segmentation. Segmentation is the key step during the point cloud processing where all homogeneous areas are identified, which describe a building facade. Usually, a large part of the segmentation approach focuses on the geometric information contained in the point cloud data by exploiting mathematical representation of a parametric surface. However, due to the complexity of the architecture, such segmentation does not suffice. Henceforth, other approaches turn to the use of color and laser intensity components. Although a variety of algorithms have been developed in this sense, problems of over-segmentation or under-segmentation are observed. In this context, we propose a new approach for point cloud segmentation aiming at a more accurate result. This approach relies on all the components of a colored point - both geometric and radiometric - combining the RGB values, laser intensity and geometric data. Our process begins with the extraction of homogeneous planar segments using the RANSAC algorithm. Next, the result is subjected to a radiometric-based segmentation, first through color similarity as one of the homogeneity criteria of a region growing algorithm, then through the use of intensity similarity for segment fusion. Experiments are performed on a facade presenting an example of Moroccan classical architecture located in Casablanca's Medina. Results show the importance of integrating all point cloud components, both geometric and radiometric.

  9. Radiometric trend of lunar calibration compared with vicarious calibration for GOSAT

    NASA Astrophysics Data System (ADS)

    Shiomi, K.; Kawakami, S.; Kuze, A.; Suto, H.; Hashiguchi, T.; Kataoka, F.; Higuchi, R.; Bruegge, C. J.; Schwandner, F. M.; Chapsky, L.

    2014-12-01

    GOSAT observes a nearly full moon for the on-orbit radiometric calibration of the FTS SWIR bands and the CAI. Lunar calibrations are operated in April/May for investigation of continuous annual radiometric trends and in June/July, corresponding to the annual Railroad Valley Cal/Val campaign. JAXA's Greenhouse Gases Observing Satellite (GOSAT) is since 2009 in polar orbit to monitor greenhouse gases such as CO2 and CH4 from space. GOSAT consists of a Fourier Transform Spectrometer (TANSO-FTS) and a Cloud and Aerosol Imager (TANSO-CAI). The FTS has 3 polarized SWIR narrow bands and a TIR wide band. The FTS observes globally with gridded points of 10 km FOV using discrete pointing. The CAI carries 4 radiometers in the UV to SWIR with high spatial resolution of 0.5-1.5 km and a wide swath of 1000 km. Since the 3rd year, lunar calibration has been planned to observe at a phase angle around 7 degrees from normal incidence. This choice avoids the reflectance opposition surge in order to target the nearly-unchanged and brightest reflectance as a function of phase angle. The Railroad Valley vicarious calibration campaign is conducted by measuring the surface reflectance and atmospheric parameters coincident with a dedicated GOSAT target observation, to derive top-of-the-atmosphere radiance. The nadir surface reflectance is collected in 500x500 m areas corresponding to the CAI resolution. The off-nadir reflectance is measured simultaneously with BRDF values, for correction. We will summarize the radiometric study of the GOSAT lunar calibration compared with the vicarious calibration. In-flight coincident calibration activities will continue with GOSAT and OCO-2.

  10. In-progress Absolute Radiometric Inflight Calibration of the LANDSAT-4 Sensors. [New Mexico

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Dinguirard, M.; Ezra, C. E.; Holm, R. G.; Jackson, R. D.; Kastner, C. J.; Palmer, J. M.; Savage, R.; Slater, P. N.

    1985-01-01

    Using selected instrumented areas at White Sands Missile Range, New Mexico as reference, radiometric calibration is to be effected on the sensors of LANDSAT 4, particularly the thematic mapper. Optical measurements made during a TM overpass are discussed. The radiances of selected large ground areas are measured in the spectral bandpasses of the TM; the total optical thickness of the atmosphere is measured in nine narrow spectral intervals. Ground truth in the form of reflectances collected for the alkalai flat region of gypsum and for the snow at White Sands is described.

  11. PRELIMINARY EVALUATION OF LANDSAT-4 THEMATIC MAPPER DATA FOR THEIR GEOMETRIC AND RADIOMETRIC ACCURACIES.

    USGS Publications Warehouse

    Podwysoki, M.H.; Falcone, N.; Bender, L.U.; Jones, O.D.

    1985-01-01

    This report describes results of some preliminary analyses of Landsat-4 Thematic Mapper data for the NASA Landsat Image Quality Analysis program. The work is being done under interagency agreement S-12407-C between the U. S. Geological Survey and NASA-Goddard Space Flight Center. Landsat-4 TM scenes for Washington, D. C. Macon, Georgia (40050-15333, September 4, 1982) and Cape Canaveral, Florida have been examined to determine their geometric and radiometric accuracy. In addition, parts of these scenes are also being analyzed to determine the ability to identify specific rock types with the added near-infrared TM bands.

  12. Analysis of radiometric signal in sedimentating suspension flow in open channel

    NASA Astrophysics Data System (ADS)

    Zych, Marcin; Hanus, Robert; Petryka, Leszek; Świsulski, Dariusz; Doktor, Marek; Mastej, Wojciech

    2015-05-01

    The article discusses issues related to the estimation of the sedimentating solid particles average flow velocity in an open channel using radiometric methods. Due to the composition of the compound, which formed water and diatomite, received data have a very weak signal to noise ratio. In the process analysis the known determining of the solid phase transportation time delay the classical cross-correlation function is the most reliable method. The use of advanced frequency analysis based on mutual spectral density function and wavelet transform of recorded signals allows a reduction of the noise contribution.

  13. A parallel-beam radiometric instrumentation system for the mass flow measurement of pneumatically conveyed solids

    NASA Astrophysics Data System (ADS)

    Barratt, I. R.; Yan, Y.; Byrne, B.

    2001-09-01

    This paper describes the design and experimental evaluation of a radiometric instrumentation system that has recently been developed for the measurement of volumetric concentration, velocity and mass flow rate of pneumatically conveyed solids. The system employs `micro' beam collimation of gamma radiation to generate multiple, parallel interrogation beams of small cross-sectional area. This configuration is shown to almost eliminate the geometrical errors associated with more conventional divergent-beam interrogation. Experimental results obtained off-line using idealized flow models, and also on-line using a pneumatic conveyor, demonstrate the performance of the system and highlight where further development is needed.

  14. A comparison between radiometric and fluorimetric methods for measuring SSAO activity.

    PubMed

    Gella, Alejandro; Sol, Montse; Bolea, Irene; Ventriglia, Mariacarla; Siotto, Mariacristina; Durany, Nuria; Squitti, Rosanna; Unzeta, Mercedes

    2013-06-01

    Semicarbazide-sensitive amine oxidase (SSAO) metabolizes the oxidative deamination of primary aromatic and aliphatic amines. The final cytotoxic products of its catalysis contribute to diseases involving vascular degeneration. The increasing interest in measuring SSAO activity has led to the development of several different methods. Herein, we compare SSAO activity results obtained with radiometric and fluorimetric methods in 49 plasma samples. Although not interchangeable, a significant correlation was obtained between methods. Considering these limitations, the fluorimetric method might replace the radioisotopic one. PMID:23400361

  15. CALFLT: A FORTRAN computer program to plot aerial radiometric data for the National Uranium Resource Evaluation

    SciTech Connect

    LaBonte, E.; Zinkl, R.J.

    1982-09-01

    CALFLT is a FORTRAN program developed to plot aerial data for the Aerial Radiometric and Magnetic Survey (ARMS) portion of the National Uranium Resource Evaluation (NURE) program. It is an inexpensive way of displaying any aerial data for mineral exploration. A magnitude profile plot of the data points along a flightline is overlayed with one of five map projections at virtually any scale. The projections convert latitude/longitude into easting/northing coordinates which are then converted into (X,Y) locations, in plotter units, for plotting.

  16. China radiometric calibration sites ground-based automatic observing systems for CAL/VAL

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Li, Xin; Rong, Zhiguo; Zhang, Lijun; Hu, Xiuqing; Ba, Xiutian

    2015-10-01

    A brand-new field observing station has been built up in the China radiometric calibration sites (CRCS) of Dunhuang Gobi for CAL/VAL, include house, observing field, power supply, tower crane, et al. Many automatic observation instruments designed and manufactured by Anhui Institute of Optics and Fine Mechanical Chinese Academy of Sciences were deployed in CRCS Dunhuang Site and introduced deeply in this paper. Followed with the finishing of the basic constructions of the field observing station, it will be an open field test and exchange platform for sharing of test data, research and infrastructure, promote exchanges and cooperation between the relevant disciplines and units.

  17. Separation of secondary refractories by type by radioresonance and x-ray radiometric methods

    SciTech Connect

    Baranovskii, N.I.; Rogozina, V.G.; Bortnikova, N.V.; Koronchevskii, A.V.; Trufanov, A.M.; Fedorov, Yu.O.

    1987-11-01

    The investigations on radiometric methods of beneficiation were made on samples of secondary refractories taken at Orsk-Khalilov Metallurgical Combine which were a mixture of aluminosilicate and magnesia (periclase and periclase-chromite) refractory scrap. The change in quality factor of the circuit under the action on it of secondary refractories was measured at a frequency of 13.56 MHz and the results of the measurements are presented. The periclase, periclase-chromite, and aluminosilicate refractory scrap change the quality factor of the circuit differently. On the basis of these investigations it may be concluded that the radioresonance method of separation may be used for separation of refractory scrap by types.

  18. Radiometric calibration of SPOT 2 HRV - A comparison of three methods

    NASA Technical Reports Server (NTRS)

    Biggar, Stuart F.; Dinguirard, Magdeleine C.; Gellman, David I.; Henry, Patrice; Jackson, Ray D.; Moran, M. S.; Slater, Philip N.

    1991-01-01

    Three methods for determining an absolute radiometric calibration of a spacecraft optical sensor are compared. They are the well-known reflectance-based and radiance-based methods and a new method based on measurements of the ratio of diffuse-to-global irradiance at the ground. The latter will be described in detail and the comparison of the three approaches will be made with reference to the SPOT-2 HRV cameras for a field campaign 1990-06-19 through 1990-06-24 at the White Sands Missile Range in New Mexico.

  19. The Future Spaceborne Hyperspectral Imager Enmap: its In-Flight Radiometric and Geometric Calibration Concept

    NASA Astrophysics Data System (ADS)

    Schneider, M.; Mller, R.; Krawzcyk, H.; Bachmann, M.; Storch, T.; Mogulsky, V.; Hofer, S.

    2012-07-01

    The German Aerospace Center DLR - namely the Earth Observation Center EOC and the German Space Operations Center GSOC - is responsible for the establishment of the ground segment of the future German hyperspectral satellite mission EnMAP (Environmental Mapping and Analysis Program). The Earth Observation Center has long lasting experiences with air- and spaceborne acquisition, processing, and analysis of hyperspectral image data. In the first part of this paper, an overview of the radiometric in-flight calibration concept including dark value measurements, deep space measurements, internal lamps measurements and sun measurements is presented. Complemented by pre-launch calibration and characterization these analyses will deliver a detailed and quantitative assessment of possible changes of spectral and radiometric characteristics of the hyperspectral instrument, e.g. due to degradation of single elements. A geometric accuracy of 100 m, which will be improved to 30 m with respect to a used reference image, if it exists, will be achieved by ground processing. Therfore, and for the required co-registration accuracy between SWIR and VNIR channels, additional to the radiometric calibration, also a geometric calibration is necessary. In the second part of this paper, the concept of the geometric calibration is presented in detail. The geometric processing of EnMAP scenes will be based on laboratory calibration results. During repeated passes over selected calibration areas images will be acquired. The update of geometric camera model parameters will be done by an adjustment using ground control points, which will be extracted by automatic image matching. In the adjustment, the improvements of the attitude angles (boresight angles), the improvements of the interior orientation (view vector) and the improvements of the position data are estimated. In this paper, the improvement of the boresight angles is presented in detail as an example. The other values and combinations follow the same rules. The geometric calibration will mainly be executed during the commissioning phase, later in the mission it is only executed if required, i.e. if the geometric accuracy of the produced images is close to or exceeds the requirements of 100 m or 30 m respectively, whereas the radiometric calibration will be executed periodically during the mission with a higher frequency during commissioning phase.

  20. The effect of spatial, spectral and radiometric factors on classification accuracy using thematic mapper data

    NASA Technical Reports Server (NTRS)

    Wrigley, R. C.; Acevedo, W.; Alexander, D.; Buis, J.; Card, D.

    1984-01-01

    An experiment of a factorial design was conducted to test the effects on classification accuracy of land cover types due to the improved spatial, spectral and radiometric characteristics of the Thematic Mapper (TM) in comparison to the Multispectral Scanner (MSS). High altitude aircraft scanner data from the Airborne Thematic Mapper instrument was acquired over central California in August, 1983 and used to simulate Thematic Mapper data as well as all combinations of the three characteristics for eight data sets in all. Results for the training sites (field center pixels) showed better classification accuracies for MSS spatial resolution, TM spectral bands and TM radiometry in order of importance.