Science.gov

Sample records for day-to-day temperature variability

  1. A prospective, descriptive study of hour-to-hour and day-to-day temperature variability of skin affected by chronic venous disorders.

    PubMed

    Kelechi, Teresa J; McNeil, Rebecca B

    2008-04-01

    Evidence suggests that skin temperature is elevated in the lower legs of individuals with the most severe stages of chronic venous disorder-related skin inflammation. Fifteen (15) patients (average age 67.7 years) with several chronic health conditions, chronic venous disorders, and a history of leg ulcers volunteered to participate in a prospective, descriptive, two-part (hourly and daily) study to test two hypotheses: 1) that skin temperature variations of chronically inflamed skin of lower legs affected by chronic venous disorders exhibit no differences in hour-to-hour and day-to-day rhythmic patterns associated with sleep and activities such as walking, exercise, or compression stocking use among four selected skin sites (two per leg) or between the legs of individuals with chronic venous disorders; and 2) that the difference in temperature between sites is unequal between legs. All study participants were at high risk for developing venous ulcers (CEAP stage 4 and 5). Skin temperature was obtained at sites with highest temperatures and/or areas of healed ulcers and mapped hourly over a 2-day period with a data logger and daily for 30 days with an infrared thermometer. No consistent, visually detectable effects due to caffeine use, eating, activity, or other variables assessed were found; only sleeping resulted in a consistent increase in skin temperature. Difference in skin temperature between measurement sites was found to be dependent on the leg on which the sites were located (P=0.1127). Because skin temperature variability could not be explained by the variables assessed, a temperature change could suggest the presence of a pathological process such as an infection or increased inflammation. Future studies to determine whether variability of skin temperature over sites affected by chronic venous disorders heralds further skin impairment are warranted. PMID:18480503

  2. Description of Day-to-Day Variability in IRI

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter; Liu, Boding; Rodriguez, Joseph E.

    2013-04-01

    The International Reference Ionosphere (IRI) describes the monthly average behavior of Earth's ionosphere based on most of the accessible and reliable ground and space observations of ionospheric parameters. IRI is doing an excellent job in accurately representing these average conditions as countless comparisons with additional data have shown and as acknowledged by the fact that international organizations (COSPAR, URSI, ISO, ECSS) have accepted IRI as their ionosphere standard. However, with our ever-increasing dependence on space technology it has become important to go beyond the monthly averages and to provide a description of the day-to-day variability of the ionosphere. We will review past and ongoing efforts to provide IRI users with a quantitative description of ionospheric variability depending on altitude, time of day, time of year, latitude and solar and magnetic activity. We will present new results from an analysis of ISIS and Alouette topside sounder data. The IRI team is also pursuing the development of an IRI Real-Time (IRI-RT) that uses assimilative algorithms or updating procedures to combine IRI with real-time data for a more accurate picture of current ionospheric conditions. We will review the status of these activities and report on latest results.

  3. Day-to-day ionospheric variability due to lower atmosphere perturbations

    NASA Astrophysics Data System (ADS)

    Liu, H.; Yudin, V. A.; Roble, R. G.

    2013-12-01

    Ionospheric day-to-day variability is a ubiquitous feature, even in the absence of appreciable geomagnetic activities. Although meteorological perturbations have been recognized as an important source of the variability, it is not well represented in previous modeling studies, and the mechanism is not well understood. This study demonstrates that TIME-GCM (Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model) constrained in the stratosphere and mesosphere by the hourly Whole Atmosphere Community Climate Model (WACCM) simulations is capable of reproducing observed features of day-to-day variability in the thermosphere-ionosphere. Realistic weather patterns in the lower atmosphere in WACCM was specified by Modern Era Retrospective reanalysis for Research and Application (MERRA). The day-to-day variations in mean zonal wind, migrating and non-migrating tides in the thermosphere, vertical and zonal ExB drifts, and ionosphere F2 layer peak electron density (NmF2) are examined. The standard deviations of the drifts and NmF2 display local time and longitudinal dependence that compare favorably with observations. Their magnitudes are 50% or more of those from observations. The day-to-day thermosphere and ionosphere variability in the model is primarily caused by the perturbations originated in lower atmosphere, since the model simulation is under constant solar minimum and low geomagnetic conditions.

  4. The observed day-to-day variability of Mars water vapor

    NASA Technical Reports Server (NTRS)

    Jakosky, Bruce M.; Lapointe, Michael R.; Zurek, Richard W.

    1987-01-01

    The diurnal variability of atmospheric water vapor as derived from the Viking MAWD data is discussed. The detection of day to day variability of atmospheric water would be a significant finding since it would place constraints on the nature of surface reservoirs. Unfortunately, the diurnal variability seen by the MAWD experiment is well correlated with the occurrence of dust and/or ice hazes, making it difficult to separate real variations from observational effects. Analysis of the day to day variability of water vapor in the Martian atmosphere suggests that the observations are, at certain locations and seasons, significantly affected by the presence of water-ice hazes. Because such effects are generally limited to specific locations, such as Tharsis, Lunae Planum, and the polar cap edge during the spring, the seasonal and latitudinal trends in water vapor that have been previously reported are not significantly affected.

  5. Day-to-day variability of oscillatory impedance and spirometry in asthma and COPD.

    PubMed

    Timmins, Sophie C; Coatsworth, Nicholas; Palnitkar, Gaurie; Thamrin, Cindy; Farrow, Catherine E; Schoeffel, Robin E; Berend, Norbert; Diba, Chantale; Salome, Cheryl M; King, Gregory G

    2013-01-15

    Variability in airway function may be a marker of disease activity in COPD and asthma. The aim was to determine the effects of repeatability and airway obstruction on day-to-day variability in respiratory system resistance (Rrs) and reactance (Xrs) measured by forced oscillation technique (FOT). Three groups of 10 subjects; normals, stable asthmatic and stable COPD subjects underwent daily FOT recordings for 7 days. Mean total and inspiratory Rrs and Xrs, and expiratory flow limitation (EFL) Index (inspiratory - expiratory Xrs), were calculated. The ICC's were high for all parameters in all groups. Repeatability, in terms of absolute units, correlated with airway obstruction and was therefore lowest in COPD. Day-to-day variability was due mostly to repeatability, with a small contribution from the mean value for some parameters. FOT measures are highly repeatable in health, stable asthma and COPD in relation to the wide range of measures between subjects. For home monitoring in asthma and COPD, either the coefficient of variation or individualized SDs could be used to define day-to-day variability. PMID:22960661

  6. Day-to-day Variability in Nap Duration Predicts Medical Morbidity in Older Adults

    PubMed Central

    Dautovich, Natalie D.; Kay, Daniel B.; Perlis, Michael L.; Dzierzewski, Joseph M.; Rowe, Meredeth A.; McCrae, Christina S.

    2014-01-01

    Objective The objectives for the present study were to: 1) examine within-person variability of nap duration and 2) assess how variability in nap duration is related to the number of health conditions in a sample of older adults. For highly variable behaviors such as sleep, it is important to consider fluctuations within the person instead of solely comparing averages of behaviors across persons. Methods Data were drawn from a previous study examining sleep in 103 community-dwelling older adults. Subjective estimates of napping behavior were obtained from sleep diaries and objective estimates of napping behavior were obtained using actigraphy. Both measures were collected for 14 consecutive days. The sampled data were aggregated in terms of: 1) average daily time spent napping and 2) average within-person fluctuations in daily nap duration. The health measure consisted of the number of self-reported health conditions. Results Both the objective and subjective measures revealed that there was considerable day-to-day fluctuation in nap duration and that variability in nap duration, not mean duration, uniquely predicted the number of health conditions, [b=.03, b*=.26, t(100)= 2.71, p = .01]. Conclusions Duration of napping in the elderly is a highly variable behavior, fluctuating as much within- as between-person. Further, variability in nap duration from day-to-day is predictive of greater medical morbidity, suggesting that clinicians should assess for inconsistencies in nap behavior in addition to duration, frequency, and timing. PMID:22369491

  7. Reliability and variability of day-to-day vault training measures in artistic gymnastics.

    PubMed

    Bradshaw, Elizabeth; Hume, Patria; Calton, Mark; Aisbett, Brad

    2010-06-01

    Inter-day training reliability and variability in artistic gymnastics vaulting was determined using a customised infra-red timing gate and contact mat timing system. Thirteen Australian high performance gymnasts (eight males and five females) aged 11-23 years were assessed during two consecutive days of normal training. Each gymnast completed a number of vault repetitions per daily session. Inter-day variability of vault run-up velocities (at -18 to -12 m, -12 to -6 m, -6 to -2 m, and -2 to 0 m from the nearest edge of the beat board), and board contact, pre-flight, and table contact times were determined using mixed modelling statistics to account for random (within-subject variability) and fixed effects (gender, number of subjects, number of trials). The difference in the mean (Mdiff) and Cohen's effect sizes for reliability assessment and intra-class correlation coefficients, and the coefficient of variation percentage (CV%) were calculated for variability assessment. Approach velocity (-18 to -2m, CV = 2.4-7.8%) and board contact time (CV = 3.5%) were less variable measures when accounting for day-to-day performance differences, than pre-flight time (CV = 17.7%) and table contact time (CV = 20.5%). While pre-flight and table contact times are relevant training measures, approach velocity and board contact time are more reliable when quantifying vaulting performance. PMID:20806844

  8. Uncovering physical processes responsible for the asymmetry of day-to-day temperature changes

    NASA Astrophysics Data System (ADS)

    Huth, Radan; Piskala, Vladimir

    2015-04-01

    Day-to-day temperature changes, and especially those of minimum temperature in winter and maximum temperature in summer, are asymmetrical: in winter, large warmings occur more frequently than large coolings and small coolings occur more frequently than small warmings. In summer, the opposite is the case. We investigate causes of this asymmetry for Prague, Czech Republic. First, we relate strong temperature changes to passages of atmospheric fronts. More specifically, large warmings in winter are related with passages of warm fronts and large coolings in summer are related with passages of cold fronts. In particular, we test the hypothesis that the days with large temperature changes (changes exceeding 3°C or 5°C) are accompanied with passages of corresponding atmospheric fronts more frequently than other days. We prove statistical significance of such a relationship between front passages and large temperature changes by means of a two-sample Kolmogorov-Smirnov test. Second, we demonstrate that small temperature changes (by up to 2°C), namely, small warmings in summer and small coolings in winter, are tightly related to anticyclonic circulation conditions and, hence, occur due to radiative processes. This relationship is investigated by comparing frequencies of anticyclonic circulation types in selected classifications from the COST733 database between the days with small temperature changes and all other days. The relationship appears to be highly statistically significant. Although the findings may seem a bit trivial, we are not aware of any study that would examine and prove the relationships between front passages and anticyclonic circulation conditions on one side, and the asymmetry of day-to-day temperature changes on the other side.

  9. Day-to-day variability in the development of plasma bubbles associated with geomagnetic disturbances

    NASA Astrophysics Data System (ADS)

    Abalde, J. R.; Sahai, Y.; Fagundes, P. R.; Becker-Guedes, F.; Bittencourt, J. A.; Pillat, V. G.; Lima, W. L. C.; Candido, C. M. N.; de Freitas, T. F.

    2009-04-01

    The development of equatorial ionospheric irregularities into large-scale ionospheric plasma bubbles continues to be an active area for scientific investigations. In this paper, we present simultaneous OI 630.0-nm emission all-sky imaging observations carried out at the Astrophysics National Laboratory (LNA), Brazopolis (22.5°S, 45.6°W, altitude 1860 m) and ionospheric sounding observations carried out at Palmas (10.2°S, 48.2°W located close to the magnetic equator) and Sao Jose dos Campos (23.2°S, 45.9°W located under the southern crest of equatorial ionospheric anomaly, close to Brazopolis), Brazil, to study the day-to-day variability in the development of ionospheric plasma bubbles during both geomagnetically disturbed and quiet periods in September-October 2002. Also, we present simultaneous complementary phase fluctuation (ROT) data obtained from the global position system (GPS) meridional chain operated by the Brazilian Institute of Geography and Statistic (IBGE). On the three nights studied in the present investigation (one geomagnetically quiet and two geomagnetically disturbed), it has been observed that the geomagnetic disturbances, during this spring equinox period, have a strong effect on the generation and development of ionospheric plasma bubbles.

  10. The day-to-day variability in ionospheric electric fields and currents

    NASA Technical Reports Server (NTRS)

    Kirchhoff, V. W. J. H.; Carpenter, L. A.

    1976-01-01

    The daily variations in ionospheric drift velocities are examined from incoherent scatter measurements at Millstone Hill. The data with summed Kp greater than 24 behave differently from those with low magnetic activity and basically follow the convection pattern but have large day-to-day variations. The influence of the magnetic conjugate point is discussed, and solar cycle variations are examined in conjunction with geomagnetic variations. Ionospheric currents calculated by using a semidiurnal neutral wind model are in good agreement with ground-based magnetograms for low magnetic activity, but the E region neutral wind model appears to be applicable only to this case.

  11. Day-to-day variability of the magnetic field measurements, preliminary results from MAGDAS chain in Egypt

    NASA Astrophysics Data System (ADS)

    Mahrous, Ayman; El-Gamry, Essam; Faheem, Amin; El-Hawary, Reham; Yumoto, Kiyohumi

    MAGDAS, the Magnetic Data Acquisition System, was successfully installed at two stations in Egypt. The first station located at Fayoum prefecture, while the second station located in South Valley at Aswan prefecture. We studied preliminary results obtained from the variability of the amplitude of diurnal variations of the solar quiet (Sq) in the three geomagnetic elements, H, D, Z. The day-to-day fluctuations of the horizontal, declination and vertical component of the geomagnetic field along MAGDAS chain in Egypt were examined. The magnetic data obtained from Fayoum and Aswan gives a good representation of the geomagnetic field at low-latitude stations.

  12. Day-to-day variability of Equatorial Ionization Anomaly over the Indian and Brazilian sectors - the role of Equatorial Electrojet

    NASA Astrophysics Data System (ADS)

    Kavutarapu, Venkatesh; Gende, Mauricio; Fagundes, Paulo Roberto; De Jesus, Rodolfo; Denardini, Clezio Marcos; De Abreu, Alessandro

    2016-07-01

    The equatorial electrojet (EEJ) is a narrow band of current flowing eastward at the ionospheric E-region altitudes along the dayside dip equator. Mutually perpendicular electric and magnetic fields over the equator results in the formation of Equatorial Ionization Anomaly (EIA) which in turn generates large electron density variabilities. Simultaneous study on the characteristics of EEJ and EIA is necessary to understand the role of EEJ on the EIA variabilities. Present study reports simultaneous variations of EEJ and GPS-TEC over Indian and Brazilian sectors to understand the role of EEJ on the day-to-day characteristics of the EIA. Magnetometer measurements during the low solar activity year 2004 are used to derive the EEJ values over the two different sectors. The characteristics of EIA are studied using two different chains of GPS receivers along the common meridian of 770E (India) and 450W (Brazil). The diurnal, seasonal and day-to-day variations of EEJ and TEC are described simultaneously. Variations of EIA during different seasons are presented along with the variations of the EEJ in the two hemispheres. The role of EEJ variations on the characteristic features of the EIA such as the strength and temporal extent of the EIA crest etc., have also been reported. Further, the time delay between the occurrences of the day maximum EEJ and the well-developed EIA are studied and corresponding results are presented in this paper. Further, the results from a study on the noon time bite-outs at the anomaly crest locations with their absence over the equator in the Indian and Brazilian sector are also discussed in this paper.

  13. Day to day variability in fat oxidation and the effect after only 1 day of change in diet composition.

    PubMed

    Støa, Eva Maria; Nyhus, Lill-Katrin; Børresen, Sandra Claveau; Nygaard, Caroline; Hovet, Åse Marie; Bratland-Sanda, Solfrid; Helgerud, Jan; Støren, Øyvind

    2016-04-01

    Indirect calorimetry is a common and noninvasive method to estimate rate of fat oxidation (FatOx) during exercise, and test-retest reliability should be considered when interpreting results. Diet also has an impact on FatOx. The aim of the present study was to investigate day to day variations in FatOx during moderate exercise given the same diet and 2 different isoenergetic diets. Nine healthy, moderately-trained females participated in the study. They performed 1 maximal oxygen uptake test and 4 FatOx tests. Habitual diets were recorded and repeated to assess day to day variability in FatOx. FatOx was also measured after 1 day of fat-rich (26.8% carbohydrates (CHO), 23.2% protein, 47.1% fat) and 1 day of CHO-rich diet (62.6% CHO, 20.1% protein, 12.4% fat). The reliability test revealed no differences in FatOx, respiratory exchange ratio (RER), oxygen uptake, carbon dioxide production, heart rate, blood lactate concentration, or blood glucose between the 2 habitual diet days. FatOx decreased after the CHO-rich diet compared with the habitual day 2 (from 0.42 ± 0.15 to 0.29 ± 0.13 g·min(-1), p < 0.05). No difference was found in FatOx between fat-rich diet and the 2 habitual diet days. FatOx was 31% lower (from 0.42 ± 0.14 to 0.29 ± 0.13 g·min(-1), p < 0.01) after the CHO-rich diet compared with the fat-rich diet. Using RER data to measure FatOx is a reliable method as long as the diet is strictly controlled. However, even a 1-day change in macronutrient composition will likely affect the FatOx results. PMID:26960444

  14. Assessing Day-to Day Variability in the Vertical Distribution of Methane, Carbon Dioxide, and Ozone over Railroad Valley, NV

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; Johnson, M. S.; Yates, E. L.; Tanaka, T.; Sweeney, C.; Tadic, J.; Roby, M.; Andrews, A. E.; Lopez, J. P.

    2013-12-01

    In-situ observations of three trace gases over a remote desert site allow for an analysis of the variability of ozone (O3), methane (CH4), and carbon dioxide (CO2) in the free troposphere. Observations from June 2013 show almost no change from one day to the next in the boundary layer (BL) up to > 4 km (30% of the atmospheric column), while mixing ratios of methane and carbon dioxide show strong variability above this altitude. Ozone values also demonstrate variability above the boundary layer, and ozone day-to-day variability in the well-mixed BL is greater than that of CO2 or CH4. Results from week-long intensives in both June 2012 and June 2013, as well as monthly measurements over the period 2012-2013, will be compared to long-term vertical profile data sets at other locations (Trinidad Head, CA; Briggsdale, CO; and the Southern Great Plains site, OK). Variability above and in the boundary layer will be reported. To assess possible sources of variability, in situ data will be analyzed with a chemical trajectory model (GEOS-Chem v9-01-03). The North America nested-grid version of GEOS-Chem utilizes varying emission inventories and model parameterizations to simulate the emissions of greenhouse gases (CO2 and CH4, in this case) and ozone precursor gases. Tagged tracer simulations in GEOS-Chem allow for the geographical source apportionment of ozone, indicating whether the observed O3 was formed in the upper troposphere, middle troposphere, stratosphere, or any user-defined boundary layer location. For this study we will focus on ozone formed in the boundary layer over Asia, the Pacific Ocean, Mexico, Canada, and the United States. The importance of daily variability in the free tropospheric values of CO2, CH4, and O3 will be discussed in the context of column measurements collected from the surface or from space. Many data assimilation systems are designed to assume that changes to the total column average should be attributed primarily to changes within the

  15. Spatial versus Day-To-Day Within-Lake Variability in Tropical Floodplain Lake CH4 Emissions – Developing Optimized Approaches to Representative Flux Measurements

    PubMed Central

    Peixoto, Roberta B.; Machado-Silva, Fausto; Marotta, Humberto; Enrich-Prast, Alex; Bastviken, David

    2015-01-01

    Inland waters (lakes, rivers and reservoirs) are now understood to contribute large amounts of methane (CH4) to the atmosphere. However, fluxes are poorly constrained and there is a need for improved knowledge on spatiotemporal variability and on ways of optimizing sampling efforts to yield representative emission estimates for different types of aquatic ecosystems. Low-latitude floodplain lakes and wetlands are among the most high-emitting environments, and here we provide a detailed investigation of spatial and day-to-day variability in a shallow floodplain lake in the Pantanal in Brazil over a five-day period. CH4 flux was dominated by frequent and ubiquitous ebullition. A strong but predictable spatial variability (decreasing flux with increasing distance to the shore or to littoral vegetation) was found, and this pattern can be addressed by sampling along transects from the shore to the center. Although no distinct day-to-day variability were found, a significant increase in flux was identified from measurement day 1 to measurement day 5, which was likely attributable to a simultaneous increase in temperature. Our study demonstrates that representative emission assessments requires consideration of spatial variability, but also that spatial variability patterns are predictable for lakes of this type and may therefore be addressed through limited sampling efforts if designed properly (e.g., fewer chambers may be used if organized along transects). Such optimized assessments of spatial variability are beneficial by allowing more of the available sampling resources to focus on assessing temporal variability, thereby improving overall flux assessments. PMID:25860229

  16. Day-to-day variability of total content, peak density and slab thickness, and the ionospheric response to geomagnetic storms. Final report, Jun 86-Sep 90

    SciTech Connect

    Fox, M.W.

    1990-11-01

    The issue of day-to-day ionospherics is of ongoing concern to users of satellites, navigation systems, and hf radio communications, and the mechanisms behind the variations are of interest to researchers. This report attempts to satisfy those operational concerns with a physical perspective, by analyzing hourly ionospheric data and developing an operationally useful model of the variations that is discussed in terms of the underlying physical processes. We describe an analysis of day-to-day variations in the total electron content, maximum electron density and equivalent slab thickness using nearly two solar cycles of observations from the American sector at mid latitudes. The report begins by quantifying day-to-day variability of these three F-region parameters and by performing a detailed correlation analysis between them. Usefulness of statistical and persistence forecasts are discussed. Then follows a study of the response of the ionosphere to geomagnetic storms, as these are the times when the variations from day to day are greatest. We then define storm patterns in terms of the departures on each day from average conditions in a storm-affected period. The average ionospheric response under a variety of conditions is described qualitatively and numerically. Individual storm patterns and common storm-related features are studied to characterize each storm and to investigate dependencies and interdependencies. The physical processes governing the observed responses and attempts to model these numerically, as well as applications to modeling real-time day-to-day variations in an operational sense, are discussed.

  17. On Day-to-Day Variability of Global Lightning Activity as Quantified from Background Schumann Resonance Observations

    NASA Astrophysics Data System (ADS)

    Mushtak, V. C.; Williams, E. R.

    2011-12-01

    final stage from the estimated positions and relative activities of the modeled "chimneys" using SR power spectra at the stations with the most reliable calibrations. Additional stabilization in the procedure has been achieved by exploiting the Le Come/Goltzman inversion algorithm that uses the empirically estimated statistical characteristics of the input parameters. When applied to electric and/or magnetic observations collected simultaneously in January 2009 from six ELF stations in Poland (Belsk), Japan (Moshiri), Hungary (Nagycenk), USA (Rhode Island), India (Shillong), and Antarctica (Syowa), the inversion procedure reveals a general repeatability of diurnal lightning scenarios with variations of "chimney" centroid locations by a few megameters, while the estimated regional activity has been found to vary from day to day by up to several tens of percent. A combined empirical-theoretical analysis of the collected data aimed at selecting the most reliably calibrated ELF stations is presently in progress. All the effort is being made to transform the relative lightning activity into absolute units by the time of this meeting. The authors are greatly thankful to all the experimentalists who generously provided their observations and related information for this study.

  18. Day-to-Day Variability of the Ionosphere: Comparisons of Model Results and Data for a Full Year

    NASA Astrophysics Data System (ADS)

    Mendillo, M.; Roble, R.; Wroten, J.; Rishbeth, H.

    2006-05-01

    The TIME-GCM at NCAR has recently been run for each day of 2002 using a series of modeling scenarios that involve traditional coupling from above (solar and geomagnetic forcings) in conjunction with (and without) coupling from below via the NCEP formulation. We compare model output for the F-layer and the E-layer with data from several ionosonde stations worldwide to assess how simulations capture true daily variability at locations ranging from sub-auroral to lower midlatitudes. We find that stations in the southern hemisphere (Port Stanley and Hobart) offer the strongest challenges to the model for F-layer patterns. We are particularly interested in the variabilities produced in the model on geomagnetically quiet days when coupling from below might be expected to be most prominent.

  19. Development of an Experimental Model to Study the Relationship Between Day-to-Day Variability in Blood Pressure and Aortic Stiffness

    PubMed Central

    Bouissou-Schurtz, Camille; Lindesay, Georges; Regnault, Véronique; Renet, Sophie; Safar, Michel E.; Molinie, Vincent; Dabire, Hubert; Bezie, Yvonnick

    2015-01-01

    We aimed to develop an animal model of long-term blood pressure variability (BPV) and to investigate its consequences on aortic damage. We hypothesized that day-to-day BPV produced by discontinuous treatment of spontaneously hypertensive rats (SHR) by valsartan may increase arterial stiffness. For that purpose, rats were discontinuously treated, 2 days a week, or continuously treated by valsartan (30 mg/kg/d in chow) or placebo. Telemetered BP was recorded during 2 min every 15 min, 3 days a week during 8 weeks to cover the full BP variations in response to the treatment schedule. Pulse wave velocity (PWV) and aortic structure evaluated by immunohistochemistry were investigated in a second set of rats treated under the same conditions. Continuous treatment with valsartan reduced systolic BP (SBP) and reversed the aortic structural alterations observed in placebo treated SHR (decrease of medial cross-sectional area). Discontinuous treatment with valsartan decreased SBP to a similar extent but increased the day-to-day BPV, short term BPV, diastolic blood pressure (DBP), and PWV as compared with continuous treatment. Despite no modifications in the elastin/collagen ratio and aortic thickness, an increase in PWV was observed following discontinuous treatment and was associated with a specific accumulation of fibronectin and its αv-integrin receptor compared with both groups of rats. Taken together the present results indicate that a discontinuous treatment with valsartan is able to induce a significant increase in day-to-day BPV coupled to an aortic phenotype close to that observed in hypertension. This experimental model should pave the way for future experimental and clinical studies aimed at assessing how long-term BPV increases aortic stiffness. PMID:26696902

  20. Day-to-Day Variability of H Component of Geomagnetic Field in Central African Sector Provided by YACM (Yaoundé-Cameroon) Amber Magnetometer Station

    NASA Astrophysics Data System (ADS)

    Etoundi Messanga, Honoré

    2015-04-01

    The geomagnetic data obtained from Amber Network station in Cameroon has been used for this study. The variability of H component of geomagnetic field has been examined by using geomagnetic field data of X and Y components recorded at AMBER magnetometer station hosted by the Department of Physics of University of Yaoundé (3.87°N, 11.52°E). The day-to-day variability of the horizontal intensity of the geomagnetic field has been examined and shows that the scattering of H component of magnetic field variation is more on disturbed than on quiet days. The signatures H of geomagnetic Sq and Sd variations in intensities in the geomagnetic element, has been studied. This paper shows that the daytime variations in intensities of geomagnetic elements H, Sq(H) and Sd(H) respectively are generally greater at diurnal-times than at night-times. This study mainly interests to answer to two questions: 1) how can geomagnetic variations be used to study the equatorial ionosphere electrodynamics and electrojet equatorial over Africa in general and Cameroon in particular? 2) How can geomagnetic variations be used to monitor and predict Space weather events in Cameroon? This study presents and interprets the results of H component of geomagnetic field variations during magnetic storms and on quiet days.

  1. An analysis of the quiet time day-to-day variability in the formation of postsunset equatorial plasma bubbles in the Southeast Asian region

    NASA Astrophysics Data System (ADS)

    Carter, B. A.; Yizengaw, E.; Retterer, J. M.; Francis, M.; Terkildsen, M.; Marshall, R.; Norman, R.; Zhang, K.

    2014-04-01

    Presented is an analysis of the occurrence of postsunset Equatorial Plasma Bubbles (EPBs) detected using a Global Positioning System (GPS) receiver at Vanimo. The three year data set shows that the EPB occurrence maximizes (minimizes) during the equinoxes (solstices), in good agreement with previous findings. The Vanimo ionosonde station is used with the GPS receiver in an analysis of the day-to-day EPB occurrence variability during the 2000 equinox period. A superposed epoch analysis (SEA) reveals that the altitude, and the change in altitude, of the F layer height is ˜1 standard deviation (1σ) larger on the days for which EPBs were detected, compared to non-EPB days. These results are then compared to results from the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM), which show strong similarities with the observations. The TIEGCM is used to calculate the flux-tube integrated Rayleigh-Taylor (R-T) instability linear growth rate. A SEA reveals that the modeled R-T growth rate is 1σ higher on average for EPB days compared to non-EPB days, and that the upward plasma drift is the most dominant contributor. It is further demonstrated that the TIEGCM's success in describing the observed daily EPB variability during the scintillation season resides in the variations caused by geomagnetic activity (as parameterized by Kp) rather than solar EUV flux (as parameterized by F10.7). Geomagnetic activity varies the modeled high-latitude plasma convection and the associated Joule heating that affects the low-latitude F region dynamo, and consequently the equatorial upward plasma drift.

  2. Day-to-day variability of VTEC and ROTI in October 2012 with impact of high-speed solar wind stream on 13 October 2012

    NASA Astrophysics Data System (ADS)

    Azzouzi, I.; Migoya-Orue, Y. O.; Coisson, P.; Amory Mazaudier, C.; Fleury, R.; Radicella, S. M.

    2016-03-01

    This paper presents the day-to-day variability of the Vertical Total Electron Content (VTEC) and the Rate of change of TEC Index (ROTI) in October 2012. We focused our attention to the impact of a high-speed solar wind stream (HSSWS) on the ionosphere in middle and low latitudes on 13 October 2012. This event was preceded by two other disturbances caused by a Coronal Mass Ejection (CME) at 05:26UT on 8 October and a HSSWS around 19:00UT on 9 October. The changes in the VTEC observed during the period between 8 and 12 October preceding the 13 October case showed a comparable response of the ionosphere in both hemispheres, varying mainly with latitude and presenting a stronger impact in the Northern hemisphere. The VTEC increased at the arrival of the CME on 8 October, then decreased, and increased again on 13 October. The solar wind speed associated with the second HSSWS reached its peak, 580 km/s around 17:00UT during the recovery phase of a geomagnetic storm started around 00:00UT on 13 October. Its impact was observed in Africa and in Eastern South America on the ROTI, an indicator of ionospheric scintillation. On 13 October, the ROTI was small over whole Africa and in Eastern South America at the moment the impact of the second HSSWS. These observations are interpreted as due to the ionospheric disturbance dynamo electric field associated with the Joule heating produced in the auroral zone by the HSSWS.

  3. Conjugate Point Equatorial Experiment (COPEX) campaign in Brazil: Electrodynamics highlights on spreadFdevelopment conditions and day-to-day variability

    NASA Astrophysics Data System (ADS)

    Abdu, M. A.; Batista, I. S.; Reinisch, B. W.; de Souza, J. R.; Sobral, J. H. A.; Pedersen, T. R.; Medeiros, A. F.; Schuch, N. J.; de Paula, E. R.; Groves, K. M.

    2009-04-01

    favoring the ESF development and that of the TEW in suppressing its growth are discussed, presenting a perspective on the ESF day-to-day and medium-term variabilities.

  4. Synoptic climatological analyses on the seasonal transition from winter to spring in Europe also with attention to the day-to-day variability (Comparing with that in East Asia)

    NASA Astrophysics Data System (ADS)

    Kato, Kuranoshin; Hamaki, Tatsuya; Haga, Yuichi; Otani, Kazuo; Kato, Haruko

    2016-04-01

    There are many stages with rapid seasonal transitions in East Asia, greatly influenced by the considerable phase differences of seasonal cycle among the Asian monsoon subsystems, resulting in the variety of "seasonal feeling". The seasonal cycle has been an important background for generation of the many kinds of arts also in Europe around the western edge of the Eurasian Continent. Especially around Germany, there are so many music or literature works in which the "May" is treated as the special season. However, more detailed examination and its comparison with that in East Asia about the seasonal evolution from winter to spring including before May would be interesting. Deeper knowledge on the seasonal cycle would contribute greatly to the cultural understanding as mentioned above, as well as for considering the detailed response of the regional climate to the global-scale impacts such as the global warming. As such, the present study examined, based mainly on the NCEP/NCAR reanalysis data during 1971-2010, the synoptic climatological features on the seasonal transition from winter to spring in Europe also with attention to the day-to-day variability, by comparing with those in East Asia (detailed analyses were made mainly for 2000/01 - 2010/11 winters). Around the region from Germany to Turkey, the surface air temperature (TS) showed rather larger day-to-day variation (including the interannual or intraseasonal variation) throughout a year than in the Japan Islands area in East Asia. Especially from December to March (the minimum period of the climatological TS in the European side), the day-to-day variation was extremely great around Germany and its northern region (to the north of around 45N/10E). Thus, the extremely low temperature events sometimes appeared around Germany till the end of March, although the seasonal mean TS was not so considerably low. The day-to-day variation of sea level pressure (SLP) was also very large where such large amplitude of TS

  5. Coherent and incoherent scatter radar study of the climatology and day-to-day variability of mean F region vertical drifts and equatorial spread F

    NASA Astrophysics Data System (ADS)

    Smith, J. M.; Rodrigues, F. S.; Fejer, B. G.; Milla, M. A.

    2016-02-01

    We conducted a comprehensive analysis of the vertical drifts and equatorial spread F (ESF) measurements made by the Jicamarca incoherent scatter radar (ISR) between 1994 and 2013. The ISR measurements allowed us to construct not only updated climatological curves of quiet-time vertical plasma drifts but also time-versus-height maps of ESF occurrence over the past two solar cycles. These curves and maps allowed us to better relate the observed ESF occurrence patterns to features in the vertical drift curves than previously possible. We identified an excessively high occurrence of post-midnight F region irregularities during December solstice and low solar flux conditions. More importantly, we also found a high occurrence of ESF events during sudden stratospheric warming (SSW) events. We also proposed and evaluated metrics of evening enhancement of the vertical drifts and ESF occurrence, which allowed us to quantify the relationship between evening drifts and ESF development. Based on a day-to-day analysis of these metrics, we offer estimates of the minimum pre-reversal enhancement (PRE) peak (and mean PRE) values observed prior to ESF development for different solar flux and seasonal conditions. We also found that ESF irregularities can reach the altitudes at least as high as 800 km at the magnetic equator even during low solar flux conditions.

  6. On the day-to-day variation of the equatorial electrojet during quiet periods

    NASA Astrophysics Data System (ADS)

    Yamazaki, Y.; Richmond, A. D.; Maute, A.; Liu, H.-L.; Pedatella, N.; Sassi, F.

    2014-08-01

    It has been known for a long time that the equatorial electrojet varies from day to day even when solar and geomagnetic activities are very low. The quiet time day-to-day variation is considered to be due to irregular variability of the neutral wind, but little is known about how variable winds drive the electrojet variability. We employ a numerical model introduced by Liu et al. (2013), which takes into account weather changes in the lower atmosphere and thus can reproduce ionospheric variability due to forcing from below. The simulation is run for May and June 2009. Constant solar and magnetospheric energy inputs are used so that day-to-day changes will arise only from lower atmospheric forcing. The simulated electrojet current shows day-to-day variability of ±25%, which produces day-to-day variations in ground level geomagnetic perturbations near the magnetic equator. The current system associated with the day-to-day variation of the equatorial electrojet is traced based on a covariance analysis. The current pattern reveals return flow at both sides of the electrojet, in agreement with those inferred from ground-based magnetometer data in previous studies. The day-to-day variation in the electrojet current is compared with those in the neutral wind at various altitudes, latitudes, and longitudes. It is found that the electrojet variability is dominated by the zonal wind at 100-120 km altitudes near the magnetic equator. These results suggest that the response of the zonal polarization electric field to variable zonal winds is the main source of the day-to-day variation of the equatorial electrojet during quiet periods.

  7. Governance: Blending Bureaucratic Rules with Day to Day Operational Realities

    PubMed Central

    Chinitz, David P

    2016-01-01

    Richard Saltman and Antonio Duran take up the challenging issue of governance in their article "Governance, Government and the Search for New Provider Models," and use two case studies of health policy changes in Sweden and Spain to shed light on the subject. In this commentary, I seek to link their conceptualization of governance, especially its interrelated roles at the macro, meso, and micro levels of health systems, with the case studies on which they report. While the case studies focus on the shifts in governance between the macro and meso levels and their impacts on achievement of desired policy outcomes, they also highlight the need to better integrate the dynamics of day to day operations within micro organizations into the overall governance picture.

  8. Macrocognition in Day-To-Day Police Incident Response

    PubMed Central

    Baber, Chris; McMaster, Richard

    2016-01-01

    Using examples of incidents that UK Police Forces deal with on a day-to-day basis, we explore the macrocognition of incident response. Central to our analysis is the idea that information relating to an incident is translated from negotiated to structured and actionable meaning, in terms of the Community of Practice of the personnel involved in incident response. Through participant observation of, and interviews with, police personnel, we explore the manner in which these different types of meaning shift over the course of incident. In this way, macrocognition relates to gathering, framing, and sharing information through the collaborative sensemaking practices of those involved. This involves two cycles of macrocognition, which we see as ‘informal’ (driven by information gathering as the Community of Practice negotiates and actions meaning) and ‘formal’ (driven by the need to assign resources to the response and the need to record incident details). The examples illustrate that these cycles are often intertwined, as are the different forms of meaning, in situation-specific ways that provide adaptive response to the demands of the incident. PMID:27014117

  9. The day-to-day occurrence of equatorial plasma bubbles measured from Vanimo, Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Carter, B. A.; Yizengaw, E.; Francis, M.; Terkildsen, M. B.; Marshall, R. A.; Norman, R.; Zhang, K.

    2013-12-01

    An analysis of the occurrence of Equatorial Plasma Bubbles (EPBs) detected using a ground-based Global Positioning System (GPS) receiver located at Vanimo in South-east Asia will be presented. The 3-year (2000-2002) dataset employed shows that the EPB occurrence maximizes (minimizes) during the equinoxes (solstices), in good agreement with previous findings. The low-latitude ionosonde station at Vanimo is used in conjunction with the GPS receiver in an analysis of the day-to-day EPB occurrence variability during the equinox period. A superposed epoch analysis of the ionosonde data reveals that the height, and the change in height, of the F layer is 1 standard deviation (1σ) larger on the days for which EPBs were detected, compared to non-EPB days. These results are interpreted using the generalized Rayleigh-Taylor (R-T) plasma instability growth rate, for which stronger upward drift of the lower-altitude F-layer plasma promotes faster growth of EPBs after sunset. These results are then compared to the results of the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM), which surprisingly show strong similarities to the observations, despite only using geomagnetic and solar activity inputs. The TIEGCM is also used to directly calculate the hourly flux-tube integrated R-T growth rate. A superposed epoch analysis reveals that the modeled R-T growth rate is a little less than 1σ higher on average for EPB days compared to non-EPB days. The implication of this result is that the TIEGCM generates almost enough day-to-day variability in order to account for the day-to-day EPB occurrence observed during the equinox. This result isn't necessarily expected due to the model's limited altitude coverage of 100-700 km (depending on solar activity) and the lack of ionospheric observation inputs. It is thought that the remaining variability could originate from either lower altitudes (e.g. atmospheric gravity waves from the troposphere) or from higher

  10. Day-to-day changes in ionospheric electron content at low latitudes

    NASA Astrophysics Data System (ADS)

    Dabas, R. S.; Bhuyan, P. K.; Tyagi, T. R.; Bhardwaj, R. K.; Lal, J. B.

    1984-06-01

    For a number of years, the ionospheric electron content (IEC) over the Indian subcontinent has been determined on the basis of the Faraday rotation of satellite radio beacon transmissions. In these determinations, use was made of the orbiting satellites BE-B and BE-C, and, for a limited period, of the geostationary satellite ATS 6. A large variability in day-to-day values of IEC was reported, and it was tried to correlate this phenomenon with magnetic activity, solar flux, or the effect of neutral winds. Tyagi (1978) observed that the day-to-day changes in IEC occur in the form of single day abnormality, and alternate day abnormality. Long-term fluctuations were found with a periodicity of about 45 days. The present investigation is concerned with a more detailed study of the observed variations. An analysis is conducted of IEC data recorded during the low phase of the solar cycle, taking into account data from six low-latitude stations covering a latitude range from approximately 15.0 deg N to 30.0 deg N.

  11. An Idiographic Examination of Day-to-Day Patterns of Substance Use Craving, Negative Affect, and Tobacco Use among Young Adults in Recovery

    ERIC Educational Resources Information Center

    Zheng, Yao; Wiebe, Richard P.; Cleveland, H. Harrington; Molenaar, Peter C. M.; Harris, Kitty S.

    2013-01-01

    Psychological constructs, such as negative affect and substance use cravings that closely predict relapse, show substantial intraindividual day-to-day variability. This intraindividual variability of relevant psychological states combined with the "one day at a time" nature of sustained abstinence warrant a day-to-day investigation of substance…

  12. Preparing Students for Front-Line Management: Non-Routine Day-to-Day Decisions

    ERIC Educational Resources Information Center

    Clydesdale, Greg; Tan, John

    2009-01-01

    Purpose: This paper attempts to reduce the gap between management education and practice. It emphasises day-to-day decisions that middle and lower level managers make. The purpose is to provide an education framework embodying a flexible approach to interpretation and solution creation, suitable for situations of ambiguity and uncertainty.…

  13. [Day-to-day support from the families from the Aide To Young Diabetics Association].

    PubMed

    Chadefaud, Nathalie

    2016-01-01

    Parents often feel helpless when their child is diagnosed with diabetes. After the initial hospitalisation and the return home, their day-to-day life has to be completely reorganised. Families from the Aide aux jeunes diabétiques association provide them a valuable support to help the development of their child. PMID:26776694

  14. The Role of Books, Television, Computers and Video Games in Children's Day to Day Lives.

    ERIC Educational Resources Information Center

    Welch, Alicia J.

    A study assessed the role of various mass media in the day-to-day lives of school-aged children. Research questions dealt with the nature of children's media experiences at home, how use of media impacts school activities, the social context of media use, interior responses to different media, and whether gender or socioeconomic differences among…

  15. The Constant Cycle: Day to Day Critical Action of the QUIPPED Project

    ERIC Educational Resources Information Center

    Medves, Jennifer M.; Paterson, Margo; Schroder, Cori; Verma, Sarita; Broers, Teresa; Chapman, Christine; O'Riordan, Anne

    2008-01-01

    Action research in the critical paradigm involves a process of continual refection in and on action including the research process itself. In the second in a series of several papers we report on the day-to-day management of the QUIPPED project. The aim was to facilitate patient centred care through inter-professional collaboration with health…

  16. Day-to-Day Inconsistency in Parent Knowledge: Links with Youth Health and Parents’ Stress

    PubMed Central

    Lippold, Melissa A.; McHale, Susan M.; Davis, Kelly D.; Kossek, Ellen Ernst

    2015-01-01

    Purpose Considerable evidence documents the linkages between higher levels of parental knowledge about youth activities and positive youth outcomes. This study investigated how day-to-day inconsistency in parental knowledge of youth activities was linked to youth behavioral, psychological, and physical health as well as parents’ stress. Methods Participants were employees in the Information Technology division of a Fortune 500 company and their children (N =129, Mean age youth = 13.39 years, 55% female). Data were collected from parents and youth via separate workplace and in-home surveys as well as telephone diary surveys on 8 consecutive evenings. We assessed day-to-day inconsistency in parental knowledge across these eight calls. Results Parents differed in their knowledge from day to day almost as much as their average knowledge scores differed from those of other parents. Controlling for mean levels of knowledge, youth whose parents exhibited more knowledge inconsistency reported more physical health symptoms (e.g., colds, flu). Knowledge inconsistency was also associated with more risky behavior for girls but greater psychological well-being for older adolescents. Parents who reported more stressors also had higher knowledge inconsistency. Conclusions Assessing only average levels of parental knowledge does not fully capture how this parenting dimension is associated with youth health. Consistent knowledge may promote youth physical health and less risky behavior for girls. Yet knowledge inconsistency also may reflect normative increases in autonomy as it was positively associated with psychological well-being for older adolescents. Given the linkages between parental stress and knowledge inconsistency, parent interventions should include stress-management components. PMID:25703318

  17. Tektite 2 habitability research program: Day-to-day life in the habitat

    NASA Technical Reports Server (NTRS)

    Nowlis, D. P.

    1972-01-01

    Because it is widely agreed that the field of environmental psychology is quite young, it was determined that a sample of recorded observations from a representative mission should be included in the report on Tektite to give the professional reader a better feeling of normal day-to-day life in the isolated habitat. Names of the crew members have been replaced with numbers and some off-color words have been replaced by more acceptable slang; some remarks have been omitted that might lead to easy identification of the subjects. Otherwise, the following pages are exactly as transcribed during the late afternoons and the evenings of the mission.

  18. Day-to-day repeatability of the Pulse Time Index of Norm

    PubMed Central

    Posokhov, Igor N; Konradi, Aleksandra O; Shlyakhto, Eugeny V; Mamontov, Oleg V; Orlov, Artemy V; Rogoza, Anatoly N

    2014-01-01

    The pulse wave velocity (PWV) threshold for hypertensive target organ damage is presently set at 10 meters per second. New 24-hour monitors (eg, BPLab® and Vasotens®) provide several PWV measurements over a period of 24–72 hours. A new parameter, ie, the Pulse Time Index of Norm (PTIN), can be calculated from these data. The PTIN is defined as the percentage of a 24-hour period during which the PWV does not exceed 10 meters per second. The aim of the present study was to test the new PTIN for clinical feasibility using day-to-day repeatability analysis. Oscillometrically generated waveform files (n=85), which were previously used for research studies, were reanalyzed using the new 2013 version software of the Vasotens technology program, which enables calculation of PTIN. The intraclass correlation coefficient was 0.98 and Cronbach’s alpha was 0.97, indicating that the PTIN has excellent day-to-day repeatability and internal consistency. The present results show adequate repeatability, and PTIN assessment using the Vasotens technology appears to be feasible. PMID:24600253

  19. Applicability of day-to-day variation in behavior for the automated detection of lameness in dairy cows.

    PubMed

    de Mol, R M; André, G; Bleumer, E J B; van der Werf, J T N; de Haas, Y; van Reenen, C G

    2013-06-01

    Lameness is a major problem in modern dairy husbandry and has welfare implications and other negative consequences. The behavior of dairy cows is influenced by lameness. Automated lameness detection can, among other methods, be based on day-to-day variation in animal behavior. Activity sensors that measure lying time, number of lying bouts, and other parameters were used to record behavior per cow per day. The objective of this research was to develop and validate a lameness detection model based on daily activity data. Besides the activity data, milking data and data from the computerized concentrate feeders were available as input data. Locomotion scores were available as reference data. Data from up to 100 cows collected at an experimental farm during 23 mo in 2010 and 2011 were available for model development. Behavior is cow-dependent, and therefore quadratic trend models were fitted with a dynamic linear model on-line per cow for 7 activity variables and 2 other variables (milk yield per day and concentrate leftovers per day). It is assumed that lameness develops gradually; therefore, a lameness alert was given when the linear trend in 2 or more of the 9 models differed significantly from zero in a direction that corresponded with lameness symptoms. The developed model was validated during the first 4 mo of 2012 with almost 100 cows on the same farm by generating lameness alerts each week. Performance on the model validation data set was comparable with performance on the model development data set. The overall sensitivity (percentage of detected lameness cases) was 85.5% combined with specificity (percentage of nonlame cow-days that were not alerted) of 88.8%. All variables contributed to this performance. These results indicate that automated lameness detection based on day-to-day variation in behavior is a useful tool for dairy management. PMID:23548300

  20. Revealing important nocturnal and day-to-day variations in fire smoke emissions through a multiplatform inversion

    NASA Astrophysics Data System (ADS)

    Saide, Pablo E.; Peterson, David A.; Silva, Arlindo; Anderson, Bruce; Ziemba, Luke D.; Diskin, Glenn; Sachse, Glen; Hair, Johnathan; Butler, Carolyn; Fenn, Marta; Jimenez, Jose L.; Campuzano-Jost, Pedro; Perring, Anne E.; Schwarz, Joshua P.; Markovic, Milos Z.; Russell, Phil; Redemann, Jens; Shinozuka, Yohei; Streets, David G.; Yan, Fang; Dibb, Jack; Yokelson, Robert; Toon, O. Brian; Hyer, Edward; Carmichael, Gregory R.

    2015-05-01

    We couple airborne, ground-based, and satellite observations; conduct regional simulations; and develop and apply an inversion technique to constrain hourly smoke emissions from the Rim Fire, the third largest observed in California, USA. Emissions constrained with multiplatform data show notable nocturnal enhancements (sometimes over a factor of 20), correlate better with daily burned area data, and are a factor of 2-4 higher than a priori estimates, highlighting the need for improved characterization of diurnal profiles and day-to-day variability when modeling extreme fires. Constraining only with satellite data results in smaller enhancements mainly due to missing retrievals near the emissions source, suggesting that top-down emission estimates for these events could be underestimated and a multiplatform approach is required to resolve them. Predictions driven by emissions constrained with multiplatform data present significant variations in downwind air quality and in aerosol feedback on meteorology, emphasizing the need for improved emissions estimates during exceptional events.

  1. Revealing important nocturnal and day-to-day variations in fire smoke emissions through a multiplatform inversion

    SciTech Connect

    Saide, Pablo E.; Peterson, David A.; de Silva, Arlindo; Anderson, Bruce; Ziemba, Luke D.; Diskin, Glenn; Sachse, Glen; Hair, Jonathan; Butler, Carolyn; Fenn, Marta; Jimenez, Jose L.; Campuzano-Jost, Pedro; Perring, Anne E.; Schwarz, Joshua P.; Markovic, Milos Z.; Russell, Phil; Redemann, Jens; Shinozuka, Yohei; Streets, David G.; Yan, Fang; Dibb, Jack; Yokelson, Robert; Toon, O. Brian; Hyer, Edward; Carmichael, Gregory R.

    2015-05-16

    We couple airborne, ground-based, and satellite observations; conduct regional simulations; and develop and apply an inversion technique to constrain hourly smoke emissions from the Rim Fire, the third largest observed in California, USA. Emissions constrained with multiplatform data show notable nocturnal enhancements (sometimes over a factor of 20), correlate better with daily burned area data, and are a factor of 2–4 higher than a priori estimates, highlighting the need for improved characterization of diurnal profiles and day-to-day variability when modeling extreme fires. Constraining only with satellite data results in smaller enhancements mainly due to missing retrievals near the emissions source, suggesting that top-down emission estimates for these events could be underestimated and a multiplatform approach is required to resolve them. Predictions driven by emissions constrained with multiplatform data present significant variations in downwind air quality and in aerosol feedback on meteorology, emphasizing the need for improved emissions estimates during exceptional events.

  2. Destigmatizing day-to-day practices: what developed countries can learn from developing countries

    PubMed Central

    ROSEN, ALAN

    2006-01-01

    The nature of and threshold for stigma associated with mental disorders appears to be different between developed and developing countries. Decreasing stigma can be achieved through a combination of the best Western educational and media strategies and the systematization of some important lessons from developing countries. At the macro-level, this involves: societal changes leading to being more inclusive and re-integrating people with mental illness into our communities; finding socially useful and culturally valued work roles for such marginalized people; re-extending our kinship networks, and re-valuing contact with people with mental illness and learning from their experiences. At the micro-level, this involves developing more destigmatizing day-to-day clinical practices, including: more holistic appraisal of disorder, abilities and needs; therapeutic optimism; a strengths orientation; engaging family and redeveloping an extended support network; celebration of age appropriate rites of passage; invoking the language of recovery; valuing veterans of mental illness as "spirit guides"; promoting consumers' community living as full citizens; engaging and involving the local community in taking responsibility for their own mental health. PMID:16757986

  3. Assessment of Day-to-Day Functioning in Prodromal and Early Huntington Disease

    PubMed Central

    Vaccarino, Anthony L; Sills, Terrence; Anderson, Karen E.; Endicott, Jean; Giuliano, Joseph; Guttman, Mark; Ho, Aileen K; Kupchak, Peter; Paulsen, Jane S.; Warner, John H.; Williams, Janet; Evans, Ken

    2011-01-01

    The Functional Rating Scale Taskforce for pre-Huntington Disease (FuRST-pHD) is a multinational, multidisciplinary initiative with the goal of developing a data-driven, comprehensive, psychometrically sound, rating scale for assessing symptoms and functional ability in prodromal and early Huntington disease (HD) gene expansion carriers. The process involves input from numerous sources to identify relevant symptom domains, including HD individuals, caregivers, and experts from a variety of fields, as well as knowledge gained from the analysis of data from ongoing large-scale studies in HD using existing clinical scales. This is an iterative process in which an ongoing series of field tests in prodromal (prHD) and early HD individuals provides the team with data on which to make decisions regarding which questions should undergo further development or testing and which should be excluded. We report here the development and assessment of the first iteration of interview questions aimed to assess functional impact in day-to-day activities in prHD and early HD individuals. PMID:21927718

  4. The consequence of day-to-day stochastic dose deviation from the planned dose in fractionated radiation therapy.

    PubMed

    Paul, Subhadip; Roy, Prasun Kumar

    2016-02-01

    Radiation therapy is one of the important treatment procedures of cancer. The day-to-day delivered dose to the tissue in radiation therapy often deviates from the planned fixed dose per fraction. This day-to-day variation of radiation dose is stochastic. Here, we have developed the mathematical formulation to represent the day-to-day stochastic dose variation effect in radiation therapy. Our analysis shows that that the fixed dose delivery approximation under-estimates the biological effective dose, even if the average delivered dose per fraction is equal to the planned dose per fraction. The magnitude of the under-estimation effect relies upon the day-to-day stochastic dose variation level, the dose fraction size and the values of the radiobiological parameters of the tissue. We have further explored the application of our mathematical formulation for adaptive dose calculation. Our analysis implies that, compared to the premise of the Linear Quadratic Linear (LQL) framework, the Linear Quadratic framework based analytical formulation under-estimates the required dose per fraction necessary to produce the same biological effective dose as originally planned. Our study provides analytical formulation to calculate iso-effect in adaptive radiation therapy considering day-to-day stochastic dose deviation from planned dose and also indicates the potential utility of LQL framework in this context. PMID:26776265

  5. Self Reports of Day-to-Day Function in a Small Cohort of People with Prodromal and Early HD

    PubMed Central

    Williams, Janet; Downing, Nancy; Vaccarino, Anthony L; Guttman, Mark; Paulsen, Jane S.

    2011-01-01

    Day-to-day functioning is a component of health-related quality of life and is an important end point for therapies to treat Huntington Disease (HD). Specific areas of day-to-day function changes have not been reported for prodromal or very early stages of HD. An exploratory self-report telephone interview was conducted with sixteen people with prodromal HD or early HD who met criteria designed to capture research participants most near to motor diagnosis. All completed semi-structured interviews on function in nine aspects of day-to-day life. Out of 16, 14 reported changes in at least one area. All day-to-day function areas were endorsed by at least one participant with driving being the most common area endorsed by 11/16. Changes in ability to perform some day-to-day tasks are experienced by people who are close to the time of clinical diagnosis for HD. Functional ability is likely to be an important component of outcome assessments of clinical trials and in ongoing clinical management. PMID:21901173

  6. Evolution of the Variability of Surface Temperature and Vegetation Density in the Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study focuses on how the variability of land surface temperature and vegetation density at the SGP ARM-CART site changes over episodic (day to day) and seasonal time scales using AVHRR satellite data. Four drying periods throughout the year are analyzed. Land surface temperature had an errati...

  7. Day to Day

    ERIC Educational Resources Information Center

    Jurecki, Dennis

    2006-01-01

    A clean, healthy and safe school provides students, faculty and staff with an environment conducive to learning and working. However, budget and staff reductions can lead to substandard cleaning practices and unsanitary conditions. Some school facility managers have been making the switch to a day-schedule to reduce security and energy costs, and…

  8. Mobile Phone-Based Unobtrusive Ecological Momentary Assessment of Day-to-Day Mood: An Explorative Study

    PubMed Central

    Ruwaard, Jeroen; Ejdys, Michal; Schrader, Niels; Sijbrandij, Marit; Riper, Heleen

    2016-01-01

    Background Ecological momentary assessment (EMA) is a useful method to tap the dynamics of psychological and behavioral phenomena in real-world contexts. However, the response burden of (self-report) EMA limits its clinical utility. Objective The aim was to explore mobile phone-based unobtrusive EMA, in which mobile phone usage logs are considered as proxy measures of clinically relevant user states and contexts. Methods This was an uncontrolled explorative pilot study. Our study consisted of 6 weeks of EMA/unobtrusive EMA data collection in a Dutch student population (N=33), followed by a regression modeling analysis. Participants self-monitored their mood on their mobile phone (EMA) with a one-dimensional mood measure (1 to 10) and a two-dimensional circumplex measure (arousal/valence, –2 to 2). Meanwhile, with participants’ consent, a mobile phone app unobtrusively collected (meta) data from six smartphone sensor logs (unobtrusive EMA: calls/short message service (SMS) text messages, screen time, application usage, accelerometer, and phone camera events). Through forward stepwise regression (FSR), we built personalized regression models from the unobtrusive EMA variables to predict day-to-day variation in EMA mood ratings. The predictive performance of these models (ie, cross-validated mean squared error and percentage of correct predictions) was compared to naive benchmark regression models (the mean model and a lag-2 history model). Results A total of 27 participants (81%) provided a mean 35.5 days (SD 3.8) of valid EMA/unobtrusive EMA data. The FSR models accurately predicted 55% to 76% of EMA mood scores. However, the predictive performance of these models was significantly inferior to that of naive benchmark models. Conclusions Mobile phone-based unobtrusive EMA is a technically feasible and potentially powerful EMA variant. The method is young and positive findings may not replicate. At present, we do not recommend the application of FSR-based mood

  9. Day-to-day measurement of patient-reported outcomes in exacerbations of chronic obstructive pulmonary disease

    PubMed Central

    Kocks, Jan Willem H; van den Berg, Jan Willem K; Kerstjens, Huib AM; Uil, Steven M; Vonk, Judith M; de Jong, Ynze P; Tsiligianni, Ioanna G; van der Molen, Thys

    2013-01-01

    Background Exacerbations of chronic obstructive pulmonary disease (COPD) are a major burden to patients and to society. Little is known about the possible role of day-to-day patient-reported outcomes during an exacerbation. This study aims to describe the day-to-day course of patient-reported health status during exacerbations of COPD and to assess its value in predicting clinical outcomes. Methods Data from two randomized controlled COPD exacerbation trials (n = 210 and n = 45 patients) were used to describe both the feasibility of daily collection of and the day-to-day course of patient-reported outcomes during outpatient treatment or admission to hospital. In addition to clinical parameters, the BORG dyspnea score, the Clinical COPD Questionnaire (CCQ), and the St George’s Respiratory Questionnaire were used in Cox regression models to predict treatment failure, time to next exacerbation, and mortality in the hospital study. Results All patient-reported outcomes showed a distinct pattern of improvement. In the multivariate models, absence of improvement in CCQ symptom score and impaired lung function were independent predictors of treatment failure. Health status and gender predicted time to next exacerbation. Five-year mortality was predicted by age, forced expiratory flow in one second % predicted, smoking status, and CCQ score. In outpatient management of exacerbations, health status was found to be less impaired than in hospitalized patients, while the rate and pattern of recovery was remarkably similar. Conclusion Daily health status measurements were found to predict treatment failure, which could help decision-making for patients hospitalized due to an exacerbation of COPD. PMID:23766644

  10. How to reduce day-to-day variation of leaf area index derived from digital cover photography?

    NASA Astrophysics Data System (ADS)

    Hwang, Y. R.; Ryu, Y.; Kimm, H.; Macfarlane, C.; Lang, M.; Sonnentag, O.

    2014-12-01

    Leaf area index (LAI) is essential for computing canopy level carbon and water fluxes. Nowadays, it is possible to automatically monitor daily LAI using low-cost sensors, such as digital cameras and LED-sensors. Recent studies have shown that RAW camera format images can improve the estimation of gap fractions and LAI compared to JPEG format. However, whether RAW-based methods can effectively reduce day-to-day variation of LAI time series has not been investigated. In this study, we used two methods to compute gap fraction. The first method separates sky and vegetation pixels using a single threshold in the blue band histogram. The second method interpolates the background sky image from pure sky pixels, and computes the transmittance from original and reconstructed images. In order to investigate which method is more accurate in reducing day-to-day variation of LAI, we first conducted a controlled experiment with punched panels which included different hole size and gap fractions on the rooftop. Then, we applied both methods to photos collected daily over a year at deciduous forest and evergreen forest in South Korea.

  11. Health care professionals' understanding and day-to-day practice of patient empowerment in diabetes; time to pause for thought?

    PubMed

    Asimakopoulou, K; Newton, P; Sinclair, A J; Scambler, S

    2012-02-01

    This exploratory study examines what Health Care Professionals (HCPs) working with diabetes patients, understand by the term 'empowerment', their attitudes towards it and whether they believe they practise in ways consistent with empowerment principles. A small sample of diabetes HCPs (N=13), from National Health Service (NHS) hospital, walk-in and General Practitioner (GP) clinics in South-East England, was interviewed. In-depth semi-structured interviews established attitudes towards and use of empowerment in day-to-day practice. Interviews were recorded, transcribed verbatim and analysed thematically. There was no clear specific understanding of what empowerment is and what it involves, although there was broad reporting of factors around education and informed choices. Disagreement was evident about the level of freedom patients should have in making choices - from leading them to the 'right' choice to an acceptance that they may have the right to choose not to be empowered. No consensus emerged on what is successful empowerment and how it is measured. The resistance of some patients to the process of empowerment in its original definition of active partnership in care, was seen as problematic by HCPs. Although empowerment is a popular concept in theory, its practical, clinical implementation day to day, can be problematic. PMID:22036297

  12. Associations between Relationship Status and Day-to-Day Health Behaviors and Weight among Diverse Young Adults

    PubMed Central

    Berge, Jerica M.; Bauer, Katherine W.; MacLehose, Rich; Eisenberg, Marla E.; Neumark-Sztainer, Dianne

    2014-01-01

    Introduction Previous research has shown strong positive associations between physical and psychological health outcomes and being in a committed relationship, such as marriage, however little research has investigated whether being in a committed relationship is protective for day-to-day health behaviors such as dietary patterns and physical activity. The main aim of this paper is to examine associations between relationship status and day-to-day health behaviors (e.g. dietary intake, physical activity) and weight status among a diverse cohort of young adults. Methods This cross-sectional study utilized data from Project EAT-III, a 10-year longitudinal population-based study (n = 1853) of Midwest young adults. Young adult participants had an average age of 25.3, and were 45% male and 55% female. Participants were socio economically and racially/ethnically diverse, including 48.4% white, 18.6% African American, 5.9% Hispanic, 19.6% Asian, 3.3% Native American, and 4.2% mixed or other race/ethnicity. Results Results indicated that married men were more likely to be overweight/obese (BMI ≥ 25) compared to single/casually dating and committed dating/engaged men. Married women were more likely to eat breakfast ≥ 5 times per week compared to women in other relationship categories. No differences were observed in young adults’ other health behaviors by relationship status. There were no significant interactions by race/ethnicity. Discussion Relationship status seems largely unrelated to young adults’ participation in physical activity and dietary behaviors. However, findings suggest that being married may be a risk factor for overweight/obesity in young adult men and may be a protective factor for other health-related behaviors associated with overweight/obesity such as eating breakfast for young adult women. PMID:24417654

  13. Better or Worse: a Study of Day-to-Day Changes over Five Months of Rosen Method Bodywork Treatment for Chronic Low Back Pain

    PubMed Central

    Fogel, Alan

    2013-01-01

    Background Fluctuations of good days and bad days—in physical symptoms and emotional states—are common for individuals with chronic illness. This pilot study examines these fluctuations during bodywork treatment. Purpose We analyzed changes in daily self-reports over a period of five months for five individuals who received weekly treatments of Rosen Method Bodywork (RMB), which uses touch and words to enhance body awareness of physical sensations and emotional states. Subjects and Design Five subjects (aged 31–56) who had chronic low back pain (CLBP) received 16 weekly treatments given by three experienced RMB practitioners. Measures Pre- and posttreatment assessments covered demographics, disability, and pain. Clients also completed daily bedtime assessments of pain, fatigue, emotional state, and sense of control during the entire treatment period. Results All clients reported reductions in pain and/or disability in post- compared to pretreatment. In spite of a high level of day-to-day variability in the daily assessments, there were significant reductions in pain and fatigue, and significant increases in positive emotional state and sense of control across the treatment period. In reaching this end, however, some clients had slow and steady improvements, some improved more rapidly, while others got worse before they got better. Conclusions The natural course of healing—with its inevitable fluctuations in symptoms—is part of a process leading to successful treatment outcomes. Rosen Method Bodywork may be especially helpful in developing and accepting both sensory and emotional body awareness changes that facilitate overall improvement. PMID:24000305

  14. IASI observations of seasonal and day-to-day variations of tropospheric ozone over three highly populated areas of China: Beijing, Shanghai, and Hong Kong

    NASA Astrophysics Data System (ADS)

    Dufour, G.; Eremenko, M.; Orphal, J.; Flaud, J.-M.

    2010-04-01

    IASI observations of tropospheric ozone over the Beijing, Shanghai and Hong Kong areas during one year (2008) have been analysed, demonstrating the capability of space-borne infrared nadir measurements to probe seasonal and even day-to-day variations of lower tropospheric ozone (0-6 km partial columns) on the regional scale of highly populated areas. The monthly variations of lower tropospheric ozone retrieved from IASI clearly show the influence of the Asian summer monsoon that brings clean air masses from the Pacific during summer. They exhibit indeed a sharp ozone maximum in late spring and early summer (May-June) followed by a summer minimum. The time periods and the intensities of the maxima and of the decreases are latitude-dependent: they are more pronounced in Hong Kong and Shanghai than in Beijing. Moreover, IASI provides the opportunity to follow the spatial variations of ozone over the surroundings of each megacity as well as its daily variability. We show here that the large lower tropospheric ozone amounts (0-6 km partial columns) observed with IASI are mainly downwind the highest populated areas in each region, thus possibly suggesting the anthropogenic origin of the large ozone amounts observed. Finally, an analysis of the mean ozone profiles over each region - for selected days with high ozone events - in association with the analysis of the meteorological situation shows that the high ozone amounts observed during winter are likely related to descents of ozone-rich air from the stratosphere, whereas in spring and summer the tropospheric ozone is likely enhanced by photochemical production in polluted areas and/or in air masses from fire plumes.

  15. Utilizing 3D-visualization to apply compulsory ALARA principles in nuclear power plant design and day-to-day operation

    SciTech Connect

    Sanders, R. L.; Lake, J. E.

    2006-07-01

    The development of an advanced visualization and simulation tool to support both design as well as day-to-day operation is presented. This tool exploits cutting edge computer graphics, physics-based effects modeling, virtual reality, and gaming technologies to establish a system that can eventually be used for the administrative planning and training of plant operators and design engineers. (authors)

  16. Day-to-day discrimination and health among Asian Indians: a population-based study of Gujarati men and women in Metropolitan Detroit.

    PubMed

    Yoshihama, Mieko; Bybee, Deborah; Blazevski, Juliane

    2012-10-01

    This study examined the relationship between experiences of day-to-day discrimination and two measures of health among Gujaratis, one of the largest ethnic groups of Asian Indians in the U.S. Data were collected via computer-assisted telephone interviews with a random sample of Gujarati men and women aged 18-64 in Metropolitan Detroit (N = 423). Using structural equation modeling, we tested two gender-moderated models of the relationship between day-to-day discrimination and health, one using the single-item general health status and the other using the 4-item emotional wellbeing measure. For both women and men, controlling for socio-demographic and other relevant characteristics, the experience of day-to-day discrimination was associated with worse emotional wellbeing. However, day-to-day discrimination was associated with the single-item self-rated general health status only for men. This study identified not only gender differences in discrimination-health associations but also the importance of using multiple questions in assessing perceived health status. PMID:21956453

  17. Predicting Day-to-Day Changes in Students' School-Related Affect from Daily Academic Experiences and Social Interactions

    ERIC Educational Resources Information Center

    Altermatt, Ellen Rydell

    2015-01-01

    This study examined the role that everyday academic successes and failures--and the interactions with family members and peers that follow these events--play in predicting day-to-day changes in children's emotional responses to school. Middle school students (N = 101; mean age = 11.62 years) completed daily assessments of their academic…

  18. Day to Day Operations of Home School Families: Selecting from a Menu of Educational Choices to Meet Students' Individual Instructional Needs

    ERIC Educational Resources Information Center

    Anthony, Kenneth V.; Burroughs, Susie

    2012-01-01

    This study examined the day to day operations of home schools. The case study method was used with four families from a larger pool of families that held membership in a home school organization. Data was gathered using interviews, observations, and artifacts. Findings suggest that these families operated their home schools using traditional…

  19. Day to day with COPD

    MedlinePlus

    Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease. Updated 2016. www.goldcopd.org/uploads/users/files/WatermarkedGlobal%20Strategy% ...

  20. Day to day with COPD

    MedlinePlus

    ... 1. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management, and prevention ... WA): Global Initiative for Chronic Obstructive Lung Disease (GOLD); 2013. Qaseem A, Wilt TJ, Weinberger SE, Hanania ...

  1. A comprehensive survey of atmospheric quasi 3 day planetary-scale waves and their impacts on the day-to-day variations of the equatorial ionosphere

    NASA Astrophysics Data System (ADS)

    Liu, Guiping; England, Scott L.; Immel, Thomas J.; Frey, Harald U.; Mannucci, Anthony J.; Mitchell, Nicholas J.

    2015-04-01

    cycle dependence on the propagation of such waves from the mesopause region to higher altitudes. We also identify that only 28 cases (19%) of the E1 TEC variations do not correspond to any E1 waves, which is consistent with the hypothesis that E1 waves are the primary cause of E1 TEC variations. Conditions that are favorable for 3 day waves to create ionospheric variations are present approximately two thirds of the time. This study quantifies the importance and frequency of atmospheric quasi 3 day planetary-scale waves on the day-to-day variations of the equatorial ionosphere using a statistical rather than case study approach.

  2. Day-to-day variations during clinical drug monitoring of morphine, morphine-3-glucuronide and morphine-6-glucuronide serum concentrations in cancer patients. A prospective observational study

    PubMed Central

    Klepstad, Pål; Hilton, Priscilla; Moen, Jorunn; Kaasa, Stein; Borchgrevink, Petter C; Zahlsen, Kolbjørn; Dale, Ola

    2004-01-01

    Background The feasibility of drug monitoring of serum concentrations of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) during chronic morphine therapy is not established. One important factor relevant to drug monitoring is to what extent morphine, M6G and M3G serum concentrations fluctuate during stable morphine treatment. Methods We included twenty-nine patients admitted to a palliative care unit receiving oral morphine (n = 19) or continuous subcutaneous (sc) morphine infusions (n = 10). Serum concentrations of morphine, M6G and M3G were obtained at the same time on four consecutive days. If readmitted, the patients were followed for another trial period. Day-to-day variations in serum concentrations and ratios were determined by estimating the percent coefficient of variation (CV = (mean/SD) ×100). Results The patients' median morphine doses were 90 (range; 20–1460) mg/24 h and 135 (range; 30–440) mg/24 h during oral and sc administration, respectively. Intraindividual fluctuations of serum concentrations estimated by median coefficients of day-to-day variation were in the oral group for morphine 46%, for M6G 25% and for M3G 18%. The median coefficients of variation were lower in patients receiving continuous sc morphine infusions (morphine 10%, M6G 13%, M3G 9%). Conclusion These findings indicate that serum concentrations of morphine and morphine metabolites fluctuate. The fluctuations found in our study are not explained by changes in morphine doses, administration of other drugs or by time for collection of blood samples. As expected the day-to-day variation was lower in patients receiving continuous sc morphine infusions compared with patients receiving oral morphine. PMID:15461818

  3. [The day-to-day routine in hospitals--standards and conflicts, based on the example of the Rothschild spital in Vienna around the year 1900].

    PubMed

    Malleier, Elisabeth

    2014-01-01

    The juxtaposition of official regulations and letters of complaint from Vienna's Rothschild Hospital shows, beyond the rhetoric and euphemisms of hospital reports, how lively and diverse day-to-day life was in a Jewish hospital around the year 1900. The letters of complaint query the official hospital rules and show that ideal and reality did not always coincide. Often, religious questions were at the root of the critique--such as doubts as to whether kosher dietary laws were adhered to--or conflicts between the agents involved, be they individuals or groups, patients, nurses, physicians or administrative staff. As part of this process, power structures, social hierarchies, patient rights and gender issues were called into question and renegotiated. PMID:25134251

  4. Surface Temperature variability from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Dang, V. T.; Aumann, H. H.

    2015-12-01

    To address the existence and possible causes of the climate hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014for the day and night conditions. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We compare the satellite data with the new surface data produced by Karl et al. (2015) who denies the reality of the climate hiatus. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The day-night difference is an indicator of the anthropogenic trend. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  5. Stereotactic Body Radiation Therapy for Liver Tumors: Impact of Daily Setup Corrections and Day-to-Day Anatomic Variations on Dose in Target and Organs at Risk

    SciTech Connect

    Mendez Romero, Alejandra; Zinkstok, Roel Th.; Wunderink, Wouter; Os, Rob M. van; Joosten, Hans; Seppenwoolde, Yvette; Nowak, Peter; Brandwijk, Rene P.; Verhoef, Cornelis; Ijzermans, Jan N.M.; Levendag, Peter C.; Heijmen, Ben J.M.

    2009-11-15

    Purpose: To assess day-to-day differences between planned and delivered target volume (TV) and organ-at-risk (OAR) dose distributions in liver stereotactic body radiation therapy (SBRT), and to investigate the dosimetric impact of setup corrections. Methods and Materials: For 14 patients previously treated with SBRT, the planning CT scan and three treatment scans (one for each fraction) were included in this study. For each treatment scan, two dose distributions were calculated: one using the planned setup for the body frame (no correction), and one using the clinically applied (corrected) setup derived from measured tumor displacements. Per scan, the two dose distributions were mutually compared, and the clinically delivered distribution was compared with planning. Doses were recalculated in equivalent 2-Gy fraction doses. Statistical analysis was performed with the linear mixed model. Results: With setup corrections, the mean loss in TV coverage relative to planning was 1.7%, compared with 6.8% without corrections. For calculated equivalent uniform doses, these figures were 2.3% and 15.5%, respectively. As for the TV, mean deviations of delivered OAR doses from planning were small (between -0.4 and +0.3 Gy), but the spread was much larger for the OARs. In contrast to the TV, the mean impact of setup corrections on realized OAR doses was close to zero, with large positive and negative exceptions. Conclusions: Daily correction of the treatment setup is required to obtain adequate TV coverage. Because of day-to-day patient anatomy changes, large deviations in OAR doses from planning did occur. On average, setup corrections had no impact on these doses. Development of new procedures for image guidance and adaptive protocols is warranted.

  6. A validation of the application of D(2)O stable isotope tracer techniques for monitoring day-to-day changes in muscle protein subfraction synthesis in humans.

    PubMed

    Wilkinson, Daniel J; Franchi, Martino V; Brook, Matthew S; Narici, Marco V; Williams, John P; Mitchell, William K; Szewczyk, Nathaniel J; Greenhaff, Paul L; Atherton, Philip J; Smith, Kenneth

    2014-03-01

    Quantification of muscle protein synthesis (MPS) remains a cornerstone for understanding the control of muscle mass. Traditional [(13)C]amino acid tracer methodologies necessitate sustained bed rest and intravenous cannulation(s), restricting studies to ~12 h, and thus cannot holistically inform on diurnal MPS. This limits insight into the regulation of habitual muscle metabolism in health, aging, and disease while querying the utility of tracer techniques to predict the long-term efficacy of anabolic/anticatabolic interventions. We tested the efficacy of the D2O tracer for quantifying MPS over a period not feasible with (13)C tracers and too short to quantify changes in mass. Eight men (22 ± 3.5 yr) undertook one-legged resistance exercise over an 8-day period (4 × 8-10 repetitions, 80% 1RM every 2nd day, to yield "nonexercised" vs. "exercise" leg comparisons), with vastus lateralis biopsies taken bilaterally at 0, 2, 4, and 8 days. After day 0 biopsies, participants consumed a D2O bolus (150 ml, 70 atom%); saliva was collected daily. Fractional synthetic rates (FSRs) of myofibrillar (MyoPS), sarcoplasmic (SPS), and collagen (CPS) protein fractions were measured by GC-pyrolysis-IRMS and TC/EA-IRMS. Body water initially enriched at 0.16-0.24 APE decayed at ~0.009%/day. In the nonexercised leg, MyoPS was 1.45 ± 0.10, 1.47 ± 0.06, and 1.35 ± 0.07%/day at 0-2, 0-4, and 0-8 days, respectively (~0.05-0.06%/h). MyoPS was greater in the exercised leg (0-2 days: 1.97 ± 0.13%/day; 0-4 days: 1.96 ± 0.15%/day, P < 0.01; 0-8 days: 1.79 ± 0.12%/day, P < 0.05). CPS was slower than MyoPS but followed a similar pattern, with the exercised leg tending to yield greater FSRs (0-2 days: 1.14 ± 0.13 vs. 1.45 ± 0.15%/day; 0-4 days: 1.13 ± 0.07%/day vs. 1.47 ± 0.18%/day; 0-8 days: 1.03 ± 0.09%/day vs. 1.40 ± 0.11%/day). SPS remained unchanged. Therefore, D2O has unrivaled utility to quantify day-to-day MPS in humans and inform on short-term changes in anabolism and

  7. Variable temperature semiconductor film deposition

    DOEpatents

    Li, X.; Sheldon, P.

    1998-01-27

    A method of depositing a semiconductor material on a substrate is disclosed. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  8. Variable temperature semiconductor film deposition

    DOEpatents

    Li, Xiaonan; Sheldon, Peter

    1998-01-01

    A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  9. SU-E-J-151: Day-To-Day Variations in Fraction-Specific Motion Modeling Using Patient 4DCBCT Images

    SciTech Connect

    Dhou, S; Cai, W; Hurwitz, M; Williams, C; Cifter, F; Myronakis, M; Lewis, J; Ionascu, D

    2015-06-15

    Purpose: The goal of this study is to quantify the interfraction reproducibility of patient-specific motion models derived from 4DCBCT acquired on the day of treatment of lung cancer stereotactic body radiotherapy (SBRT) patients. Methods: Motion models are derived from patient 4DCBCT images acquired daily over 3–5 fractions of treatment by 1) applying deformable image registration between each 4DCBCT image and a reference phase from that day, resulting in a set of displacement vector fields (DVFs), and 2) performing principal component analysis (PCA) on the DVFs to derive a motion model. The motion model from the first day of treatment is compared to motion models from each successive day of treatment to quantify variability in motion models generated from different days. Four SBRT patient datasets have been acquired thus far in this IRB approved study. Results: Fraction-specific motion models for each fraction and patient were derived and PCA eigenvectors and their associated eigenvalues are compared for each fraction. For the first patient dataset, the average root mean square error between the first two eigenvectors associated with the highest two eigenvalues, in four fractions was 0.1, while it was 0.25 between the last three PCA eigenvectors associated with the lowest three eigenvalues. It was found that the eigenvectors and eigenvalues of PCA motion models for each treatment fraction have variations and the first few eigenvectors are shown to be more stable across treatment fractions than others. Conclusion: Analysis of this dataset showed that the first two eigenvectors of the PCA patient-specific motion models derived from 4DCBCT were stable over the course of several treatment fractions. The third, fourth, and fifth eigenvectors had larger variations.

  10. Real-time evaluation of milk quality as reflected by clotting parameters of individual cow's milk during the milking session, between day-to-day and during lactation.

    PubMed

    Leitner, Gabriel; Merin, Uzi; Jacoby, Shamay; Bezman, Dror; Lemberskiy-Kuzin, Liubov; Katz, Gil

    2013-09-01

    together with high milk yield >50 l/day, and late in lactation together with low milk yield<15 l/day and estrous (0 to 5 days) were also important influencing factors for low-quality milk. However, ∼50% of the tested variables did not explain any of the factors responsible for the cow producing milk in the low - 10% Afi-CF. PMID:23537499

  11. Variable temperature seat climate control system

    DOEpatents

    Karunasiri, Tissa R.; Gallup, David F.; Noles, David R.; Gregory, Christian T.

    1997-05-06

    A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

  12. Variable effects of temperature on insect herbivory

    PubMed Central

    Burkepile, Deron E.; Parker, John D.

    2014-01-01

    Rising temperatures can influence the top-down control of plant biomass by increasing herbivore metabolic demands. Unfortunately, we know relatively little about the effects of temperature on herbivory rates for most insect herbivores in a given community. Evolutionary history, adaptation to local environments, and dietary factors may lead to variable thermal response curves across different species. Here we characterized the effect of temperature on herbivory rates for 21 herbivore-plant pairs, encompassing 14 herbivore and 12 plant species. We show that overall consumption rates increase with temperature between 20 and 30 °C but do not increase further with increasing temperature. However, there is substantial variation in thermal responses among individual herbivore-plant pairs at the highest temperatures. Over one third of the herbivore-plant pairs showed declining consumption rates at high temperatures, while an approximately equal number showed increasing consumption rates. Such variation existed even within herbivore species, as some species exhibited idiosyncratic thermal response curves on different host plants. Thus, rising temperatures, particularly with respect to climate change, may have highly variable effects on plant-herbivore interactions and, ultimately, top-down control of plant biomass. PMID:24860701

  13. Variability of the Martian thermospheric temperatures during the last 7 Martian Years

    NASA Astrophysics Data System (ADS)

    Gonzalez-Galindo, Francisco; Lopez-Valverde, Miguel Angel; Millour, Ehouarn; Forget, François

    2014-05-01

    The temperatures and densities in the Martian upper atmosphere have a significant influence over the different processes producing atmospheric escape. A good knowledge of the thermosphere and its variability is thus necessary in order to better understand and quantify the atmospheric loss to space and the evolution of the planet. Different global models have been used to study the seasonal and interannual variability of the Martian thermosphere, usually considering three solar scenarios (solar minimum, solar medium and solar maximum conditions) to take into account the solar cycle variability. However, the variability of the solar activity within the simulated period of time is not usually considered in these models. We have improved the description of the UV solar flux included on the General Circulation Model for Mars developed at the Laboratoire de Météorologie Dynamique (LMD-MGCM) in order to include its observed day-to-day variability. We have used the model to simulate the thermospheric variability during Martian Years 24 to 30, using realistic UV solar fluxes and dust opacities. The model predicts and interannual variability of the temperatures in the upper thermosphere that ranges from about 50 K during the aphelion to up to 150 K during perihelion. The seasonal variability of temperatures due to the eccentricity of the Martian orbit is modified by the variability of the solar flux within a given Martian year. The solar rotation cycle produces temperature oscillations of up to 30 K. We have also studied the response of the modeled thermosphere to the global dust storms in Martian Year 25 and Martian Year 28. The atmospheric dynamics are significantly modified by the global dust storms, which induces significant changes in the thermospheric temperatures. The response of the model to the presence of both global dust storms is in good agreement with previous modeling results (Medvedev et al., Journal of Geophysical Research, 2013). As expected, the simulated

  14. Sea surface temperature variability: patterns and mechanisms.

    PubMed

    Deser, Clara; Alexander, Michael A; Xie, Shang-Ping; Phillips, Adam S

    2010-01-01

    Patterns of sea surface temperature (SST) variability on interannual and longer timescales result from a combination of atmospheric and oceanic processes. These SST anomaly patterns may be due to intrinsic modes of atmospheric circulation variability that imprint themselves upon the SST field mainly via surface energy fluxes. Examples include SST fluctuations in the Southern Ocean associated with the Southern Annular Mode, a tripolar pattern of SST anomalies in the North Atlantic associated with the North Atlantic Oscillation, and a pan-Pacific mode known as the Pacific Decadal Oscillation (with additional contributions from oceanic processes). They may also result from coupled ocean-atmosphere interactions, such as the El Niño-Southern Oscillation phenomenon in the tropical Indo-Pacific, the tropical Atlantic Niño, and the cross-equatorial meridional modes in the tropical Pacific and Atlantic. Finally, patterns of SST variability may arise from intrinsic oceanic modes, notably the Atlantic Multidecadal Oscillation. PMID:21141660

  15. Middle Pliocene sea surface temperature variability

    USGS Publications Warehouse

    Dowsett, H.J.; Chandler, M.A.; Cronin, T. M.; Dwyer, G.S.

    2005-01-01

    Estimates of sea surface temperature (SST) based upon foraminifer, diatom, and ostracod assemblages from ocean cores reveal a warm phase of the Pliocene between about 3.3 and 3.0 Ma. Pollen records and plant megafossils, although not as well dated, show evidence for a warmer climate at about the same time. Increased greenhouse forcing and altered ocean heat transport are the leading candidates for the underlying cause of Pliocene global warmth. Despite being a period of global warmth, this interval encompasses considerable variability. Two new SST reconstructions are presented that are designed to provide a climatological error bar for warm peak phases of the Pliocene and to document the spatial distribution and magnitude of SST variability within the mid-Pliocene warm period. These data suggest long-term stability of low-latitude SST and document greater variability in regions of maximum warming. Copyright 2005 by the American Geophysical Union.

  16. Thermoelectric convection in a variable temperature field

    NASA Astrophysics Data System (ADS)

    Belyaev, A. V.; Smorodin, B. L.

    2008-03-01

    We have studied the convective instability of a horizontal layer of a liquid semiconductor or an ionic melt in the presence of a variable temperature gradient under microgravity conditions in the case where an excess charge can appear only as a result of the thermostimulated diffusion. Thresholds for the onset of thermoelectric convective instability are determined. It is established that, under variable thermal action with a zero mean value, perturbations of a subharmonic response are absent. Depending on the amplitude and frequency of modulation and on the physical properties of the semiconductor (or the melt), synchronous perturbations are differently manifested and belong to various classes. The amplitudes and frequencies of an external action necessary for the effective suppression of thermoelectric convection are determined.

  17. Physical characteristics of Eurasian winter temperature variability

    NASA Astrophysics Data System (ADS)

    Kim, Kwang-Yul; Son, Seok-Woo

    2016-04-01

    Despite the on-going global warming, recent winters in Eurasian mid-latitudes were much colder than average. In an attempt to better understand the physical characteristics for cold Eurasian winters, major sources of variability in surface air temperature (SAT) are investigated based on cyclostationary EOF analysis. The two leading modes of SAT variability represent the effect of Arctic amplification (AA) and the Arctic oscillation (AO), respectively. These two modes are distinct in terms of the physical characteristics, including surface energy fluxes and tropospheric circulations, and result in significantly different winter SAT patterns over the Eurasian continent. The AA-related SAT anomalies are dipolar with warm Arctic, centered at the Barents–Kara Seas, and cold East Asia. In contrast, the negative AO-related SAT anomalies are characterized by widespread cold anomalies in Northern Eurasia. Relative importance of the AA and the negative AO contributions to cold Eurasian winters is sensitive to the region of interest.

  18. Variable-Temperature Critical-Current Measurements

    SciTech Connect

    L. F. Goodrich; T. C. Stauffer

    2009-05-19

    This is the final report of a three year contract that covered 09/19/2005 to 07/14/2008. We requested and received a no cost time extension for the third year, 07/15/2007 to 07/14/2008, to allow DoE to send us funds if they became available during that year. It turned out that we did not receive any funding for the third year. The following paper covers our variable-temperature critical-current measurements. We made transport critical-current (Ic) measurements on commercial multifilamentary Nb3Sn strands at temperatures (T) from 4 to 17 K and magnetic fields (H) from 0 to 14 T. One of the unique features of our measurements is that we can cover a wide range of critical currents from less than 0.1 A to over 700 A.

  19. Variability of the thermospheric temperatures of Mars during 9 Martian Years as given by a ground-to-exosphere Global Climate Model

    NASA Astrophysics Data System (ADS)

    Gonzalez-Galindo, Francisco; Forget, Francois; Garcia-Comas, Maya; Millour, Ehouarn; Lopez-Valverde, Miguel; Montabone, Luca

    2016-07-01

    The temperature of the Martian upper thermosphere is one of the main factors affecting the rate of the different escape to space processes which shape the Martian atmosphere and its long-term evolution. A good knowledge of the variability of this parameter is thus very important in order to gain a deeper understanding of the present-day escape rate and of the evolutive history of Mars. We have used a ground-to-exosphere Global Climate Model, the LMD-MGCM, to simulate the variability of the temperatures at the Martian exobase during the last 9 Martian Years (MY24-MY32, approximately 17 terrestrial years). The simulations include for the first time a realistic day-to-day variability of the UV solar flux. The simulated temperatures are in good agreement with the exospheric temperatures derived from Precise Orbit Determination of Mars Global Surveyor. A significant inter-annual variability of the temperatures, due to both the 11 year solar cycle and the variability of the dust load in the lower atmosphere, is predicted by the model. The variation in the solar output produced by the 27 day solar rotation cycle is seen in the simulated exobase temperatures. We also find that the global dust storms in MY25 and MY28 significantly impact the temperatures at the exobase. These results underline the importance of properly taking into account the dust and solar variabilities to simulate the upper atmosphere of Mars.

  20. Borehole temperature variability at Hoher Sonnblick, Austria

    NASA Astrophysics Data System (ADS)

    Heinrich, Georg; Schöner, Wolfgang; Prinz, Rainer; Pfeiler, Stefan; Reisenhofer, Stefan; Riedl, Claudia

    2016-04-01

    The overarching aim of the project 'Atmosphere - permafrost relationship in the Austrian Alps - atmospheric extreme events and their relevance for the mean state of the active layer (ATMOperm)' is to improve the understanding of the impacts of atmospheric extreme events on the thermal state of the active layer using a combined measurement and modeling approach as the basis for a long-term monitoring strategy. For this purpose, the Sonnblick Observatory at the summit of Hoher Sonnblick (3106 m.a.s.l) is particularly well-suited due to its comprehensive long-term atmospheric and permafrost monitoring network (i.a. three 20 m deep boreholes since 2007). In ATMOperm, a robust and accurate permanent monitoring of active layer thickness at Hoher Sonnblick will be set up using innovative monitoring approaches by automated electrical resistivity tomography (ERT). The ERT monitoring is further supplemented by additional geophysical measurements such as ground penetrating radar, refraction seismic, electromagnetic induction and transient electromagnetics in order to optimally complement the gained ERT information. On the other hand, atmospheric energy fluxes over permafrost ground and their impact on the thermal state of permafrost and active layer thickness with a particular focus on atmospheric extreme events will be investigated based on physically-based permafrost modeling. For model evaluation, the borehole temperature records will play a key role and, therefore, an in-depth quality control of the borehole temperatures is an important prerequisite. In this study we will show preliminary results regarding the borehole temperature variability at Hoher Sonnblick with focus on the active layer. The borehole temperatures will be related to specific atmospheric conditions using the rich data set of atmospheric measurements of the site in order to detect potential errors in the borehole temperature measurements. Furthermore, we will evaluate the potential of filling gaps in

  1. The Day-to-Day Acute Effect of Wake Therapy in Patients with Major Depression Using the HAM-D6 as Primary Outcome Measure: Results from a Randomised Controlled Trial

    PubMed Central

    Martiny, Klaus; Refsgaard, Else; Lund, Vibeke; Lunde, Marianne; Sørensen, Lene; Thougaard, Britta; Lindberg, Lone; Bech, Per

    2013-01-01

    Background This paper reports day-to-day data for from a one-week intervention phase, part of a 9-weeks randomised parallel study with patient having major depression (data from weekly visits have been reported). Wake therapy (sleep deprivation) has an established antidepressant effect with onset of action within hours. Deterioration on the following night’s sleep is, however, common, and we used daily light therapy and sleep time stabilisation as a preventive measure. In particular, we evaluated the day-to-day acute effect of and tolerance to sleep deprivation and examined predictors of response. Methods Patients were assessed at psychiatric inpatient wards. In the wake group (n = 36), patients did three wake therapies in combination with light therapy each morning together with sleep time stabilisation. In the exercise group (n = 38), patients did daily exercise. Hamilton subscale scores were primary outcome (not blinded), secondary outcome was self-assessment data from the Preskorn scale and sleep. Results Patients in the wake therapy group had an immediate, large, stable, and statistically significant better antidepressant effect than patients in the exercise group with response rates at day5 of 75.0%/25.1% and remission rates of 58.6%/6.0%, respectively. The response and remission rates were diminished at day8 with response rates of 41.9%/10.1% and remission rates of 19.4%/4.7%, respectively. Patients and ward personnel found the method applicable with few side effects. Positive diurnal variation (mood better in the evening) predicted a larger response to wake therapy. In the wake group napping on days after intervention predicted greater deterioration on day8. Conclusions The intervention induced an acute antidepressant response without relapse between wake nights but with a diminishing effect after intervention. Development is still needed to secure maintenance of response. Avoiding napping in the days after wake therapy is important. Trial

  2. Control of radiation and evaporation on temperature variability in a WRF regional climate simulation: comparison with colocated long term ground based observations near Paris

    NASA Astrophysics Data System (ADS)

    Bastin, S.; Chiriaco, M.; Drobinski, P.

    2016-03-01

    The objective of this paper is to understand how large-scale processes, cloud cover and surface fluxes affect the temperature variability over the SIRTA site, near Paris, and in a regional climate simulation performed in the frame of HyMeX/Med-CORDEX programs. This site is located in a climatic transitional area where models usually show strong dispersions despite the significant influence of large scale on interannual variability due to its western location. At seasonal time scale, the temperature is mainly controlled by surface fluxes. In the model, the transition from radiation to soil moisture limited regime occurs earlier than in observations leading to an overestimate of summertime temperature. An overestimate of shortwave radiation (SW), consistent with a lack of low clouds, enhances the soil dryness. A simulation with a wet soil is used to better analyse the relationship between dry soil and clouds but while the wetter soil leads to colder temperature, the cloud cover during daytime is not increased due to the atmospheric stability. At shorter time scales, the control of surface radiation becomes higher. In the simulation, higher temperatures are associated with higher SW. A wet soil mitigates the effect of radiation due to modulation by evaporation. In observations, the variability of clouds and their effect on SW is stronger leading to a nearly constant mean SW when sorted by temperature quantile but a stronger impact of cloud cover on day-to-day temperature variability. Impact of cloud albedo effect on precipitation is also compared.

  3. Precision and Variability in Bacterial Temperature Sensing

    PubMed Central

    Yoney, Anna; Salman, Hanna

    2015-01-01

    In Escherichia coli, the ratio of the two most abundant chemoreceptors, Tar/Tsr, has become the focus of much attention in bacterial taxis studies. This ratio has been shown to change under various growth conditions and to determine the response of the bacteria to the environment. Here, we present a study that makes a quantitative link between the ratio Tar/Tsr and the favored temperature of the cell in a temperature gradient and in various chemical environments. From the steady-state density-profile of bacteria with one dominant thermo-sensor, Tar or Tsr, we deduce the response function of each receptor to temperature changes. Using the response functions of both receptors, we determine the relationship between the favored temperature of wild-type bacteria with mixed clusters of receptors and the receptor ratio. Our model is based on the assumption that the behavior of a wild-type bacterium in a temperature gradient is determined by a linear combination of the independent responses of the two receptors, factored by the receptor’s relative abundance in the bacterium. This is confirmed by comparing our model predictions with measurements of the steady-state density-profile of several bacterial populations in a temperature gradient. Our results reveal that the density-profile of wild-type bacteria can be accurately described by measuring the distribution of the ratio Tar/Tsr in the population, which is then used to divide the population into groups with distinct Tar/Tsr values, whose behavior can be described in terms of independent Gaussian distributions. Each of these Gaussians is centered about the favored temperature of the subpopulation, which is determined by the receptor ratio, and has a width defined by the temperature-dependent speed and persistence time. PMID:25992721

  4. The influence of model resolution on temperature variability

    NASA Astrophysics Data System (ADS)

    Klavans, Jeremy M.; Poppick, Andrew; Sun, Shanshan; Moyer, Elisabeth J.

    2016-08-01

    Understanding future changes in climate variability, which can impact human activities, is a current research priority. It is often assumed that a key part of this effort involves improving the spatial resolution of climate models; however, few previous studies comprehensively evaluate the effects of model resolution on variability. In this study, we systematically examine the sensitivity of temperature variability to horizontal atmospheric resolution in a single model (CCSM3, the Community Climate System Model 3) at three different resolutions (T85, T42, and T31), using spectral analysis to describe the frequency dependence of differences. We find that in these runs, increased model resolution is associated with reduced temperature variability at all but the highest frequencies (2-5 day periods), though with strong regional differences. (In the tropics, where temperature fluctuations are smallest, increased resolution is associated with increased variability.) At all resolutions, temperature fluctuations in CCSM3 are highly spatially correlated, implying that the changes in variability with model resolution are driven by alterations in large-scale phenomena. Because CCSM3 generally overestimates temperature variability relative to reanalysis output, the reductions in variability associated with increased resolution tend to improve model fidelity. However, the resolution-related variability differences are relatively uniform with frequency, whereas the sign of model bias changes at interannual frequencies. This discrepancy raises questions about the mechanisms underlying the improvement at subannual frequencies. The consistent response across frequencies also implies that the atmosphere plays a significant role in interannual variability.

  5. Temperature and size variabilities of the Western Pacific Warm Pool

    NASA Technical Reports Server (NTRS)

    Yan, Xiao-Hai; Ho, Chung-Ru; Zheng, Quanan; Klemas, Vic

    1992-01-01

    Variabilities in sea-surface temperature and size of the Western Pacific Warm Pool were tracked with 10 years of satellite multichannel sea-surface temperature observations from 1982 to 1991. The results show that both annual mean sea-surface temperature and the size of the warm pool increased from 1983 to 1987 and fluctuated after 1987. Possible causes of these variations include solar irradiance variabilities, El Nino-Southern Oscillaton events, volcanic activities, and global warming.

  6. Predation life history responses to increased temperature variability.

    PubMed

    Barbosa, Miguel; Pestana, Joao; Soares, Amadeu M V M

    2014-01-01

    The evolution of life history traits is regulated by energy expenditure, which is, in turn, governed by temperature. The forecasted increase in temperature variability is expected to impose greater stress to organisms, in turn influencing the balance of energy expenditure and consequently life history responses. Here we examine how increased temperature variability affects life history responses to predation. Individuals reared under constant temperatures responded to different levels of predation risk as appropriate: namely, by producing greater number of neonates of smaller sizes and reducing the time to first brood. In contrast, we detected no response to predation regime when temperature was more variable. In addition, population growth rate was slowest among individuals reared under variable temperatures. Increased temperature variability also affected the development of inducible defenses. The combined effects of failing to respond to predation risk, slower growth rate and the miss-match development of morphological defenses supports suggestions that increased variability in temperature poses a greater risk for species adaptation than that posed by a mean shift in temperature. PMID:25250677

  7. Predation Life History Responses to Increased Temperature Variability

    PubMed Central

    Barbosa, Miguel; Pestana, Joao; Soares, Amadeu M. V. M.

    2014-01-01

    The evolution of life history traits is regulated by energy expenditure, which is, in turn, governed by temperature. The forecasted increase in temperature variability is expected to impose greater stress to organisms, in turn influencing the balance of energy expenditure and consequently life history responses. Here we examine how increased temperature variability affects life history responses to predation. Individuals reared under constant temperatures responded to different levels of predation risk as appropriate: namely, by producing greater number of neonates of smaller sizes and reducing the time to first brood. In contrast, we detected no response to predation regime when temperature was more variable. In addition, population growth rate was slowest among individuals reared under variable temperatures. Increased temperature variability also affected the development of inducible defenses. The combined effects of failing to respond to predation risk, slower growth rate and the miss-match development of morphological defenses supports suggestions that increased variability in temperature poses a greater risk for species adaptation than that posed by a mean shift in temperature. PMID:25250677

  8. Variable Temperature Equipment for a Commercial Magnetic Susceptibility Balance

    ERIC Educational Resources Information Center

    Lotz, Albert

    2008-01-01

    Variable temperature equipment for the magnetic susceptibility balance MSB-MK1 of Sherwood Scientific, Ltd., is described. The sample temperature is controlled with streaming air heated by water in a heat exchanger. Whereas the balance as sold commercially can be used only for room temperature measurements, the setup we designed extends the…

  9. Variability of Soil Temperature: A Spatial and Temporal Analysis.

    ERIC Educational Resources Information Center

    Walsh, Stephen J.; And Others

    1991-01-01

    Discusses an analysis of the relationship of soil temperatures at 3 depths to various climatic variables along a 200-kilometer transect in west-central Oklahoma. Reports that temperature readings increased from east to west. Concludes that temperature variations were explained by a combination of spatial, temporal, and biophysical factors. (SG)

  10. Contribution of solar radiation to decadal temperature variability over land

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Dickinson, Robert

    2014-05-01

    Global air temperature has become the primary metric for judging global climate change. The variability of global temperature on a decadal timescale is still poorly understood. This paper examines further one suggested hypothesis, that variations in solar radiation reaching the surface (Rs) have caused much of the observed decadal temperature variability. Because Rs only heats air during the day, its variability is plausibly related to the variability of diurnal temperature range (daily maximum temperature minus its minimum). We show that the variability of diurnal temperature range is consistent with the variability of Rs at timescales from monthly to decadal. This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of Rs to decadal temperature variability. It shows that Rs over land globally peaked in the 1930s, substantially decreased from the 1940s to the 1970s, and changed little after that. Reduction of Rs caused a reduction of more than 0.2 °C in mean temperature during May to October from the 1940s through the 1970s, and a reduction of nearly 0.2 °C in mean air temperature during November to April from the 1960s through the 1970s. This cooling accounts in part for the near-constant temperature from the 1930s into the 1970s. Since then, neither the rapid increase in temperature from the 1970s through the 1990s nor the slowdown of warming in the early twenty-first century appear to be significantly related to changes of Rs.

  11. Contribution of solar radiation to decadal temperature variability over land

    PubMed Central

    Wang, Kaicun; Dickinson, Robert E.

    2013-01-01

    Global air temperature has become the primary metric for judging global climate change. The variability of global temperature on a decadal timescale is still poorly understood. This paper examines further one suggested hypothesis, that variations in solar radiation reaching the surface (Rs) have caused much of the observed decadal temperature variability. Because Rs only heats air during the day, its variability is plausibly related to the variability of diurnal temperature range (daily maximum temperature minus its minimum). We show that the variability of diurnal temperature range is consistent with the variability of Rs at timescales from monthly to decadal. This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of Rs to decadal temperature variability. It shows that Rs over land globally peaked in the 1930s, substantially decreased from the 1940s to the 1970s, and changed little after that. Reduction of Rs caused a reduction of more than 0.2 °C in mean temperature during May to October from the 1940s through the 1970s, and a reduction of nearly 0.2 °C in mean air temperature during November to April from the 1960s through the 1970s. This cooling accounts in part for the near-constant temperature from the 1930s into the 1970s. Since then, neither the rapid increase in temperature from the 1970s through the 1990s nor the slowdown of warming in the early twenty-first century appear to be significantly related to changes of Rs. PMID:23980136

  12. Variable temperature electrochemical strain microscopy of Sm-doped ceria

    SciTech Connect

    Jesse, Stephen; Morozovska, A. N.; Kalinin, Sergei V; Eliseev, E. A.; Yang, Nan; Doria, Sandra; Tebano, Antonello

    2013-01-01

    Variable temperature electrochemical strain microscopy has been used to study the electrochemical activity of Sm-doped ceria as a function of temperature and bias. The electrochemical strain microscopy hysteresis loops have been collected across the surface at different temperatures and the relative activity at different temperatures has been compared. The relaxation behavior of the signal at different temperatures has been also evaluated to relate kinetic process during bias induced electrochemical reactions with temperature and two different kinetic regimes have been identified. The strongly non-monotonic dependence of relaxation behavior on temperature is interpreted as evidence for water-mediated mechanisms.

  13. Variability of dayside electron temperature at Venus

    NASA Technical Reports Server (NTRS)

    Mahajan, K. K.; Ghosh, S.; Paul, R.; Hoegy, W. R.

    1994-01-01

    Langmuir probe measurements on Pioneer Venus Orbiter show that electron temperature (Te) profiles exhibit two distinct regions. The lower, but more extended region is in the main ionosphere where Te increases slowly with altitude. The other, less extended region is in the ionopause, where Te rise sharply with altitude. If horizontal magnetic fields and flux ropes in the ionosphere inhibit vertical thermal conductivity sufficiently, then the observed Te profile could be explained with EUV as the major heat source (Cravens et al., 1980). The rise in Te in the ionopause region has generally been attributed to solar wind heating (Brace and Kliore, 1991). We suggest that this sharp rise in Te is due primarily to the steep fall in electron density, Ne. If the heating rate is essentially unchanged and heat conduction is not of primary importance, then a steep rise in Te will maintain a constant electron cooling rate for a steeply falling Ne. We have observed large orbit to orbit variations in Te in the ionopause region which are found to be inversely related to changes in Ne. Variations in solar wind dynamic pressure do not seem to have a direct effect on Te, rather the effect is indirect coming through the sharp decrease in Ne.

  14. Ontogenetic thermal tolerance and performance of ectotherms at variable temperatures.

    PubMed

    Cavieres, G; Bogdanovich, J M; Bozinovic, F

    2016-07-01

    Early experience and environmental conditions during ontogeny may affect organismal structure, physiology and fitness. Here, we assessed the effect of developmental acclimation to environmental thermal variability on walking speed in Drosophila melanogaster adults. Our results showed a shift in the performance curve to the right. Thus, upper and lower thermal limits exhibited developmental plasticity. Additionally, in constant and variable climatic scenarios, flies shifted to the right the optimum temperature but the maximum performance decreased only in flies reared on high temperatures and high thermal variability. Overall, we showed that environmental cues during ontogeny might help to construct phenotypic variation, which supports the hypothesis of ontogenetic dependence of thermal tolerances. PMID:27118598

  15. The role of subsurface soil temperature feedbacks in summer surface air temperature variability over East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2012-12-01

    Soil temperature, an important component of land surface, can influence the climate through its effects on surface energy and water budgets and resulted changes in regional atmospheric circulation. However, the effects of soil temperature on climate variations have been less discussed. This study investigates the role of subsurface soil temperature feedbacks in influencing summer surface air temperature variability over East Asia by means of regional climate model (RCM) simulations. For this aim, two long-term simulations with and without subsurface soil temperature feedbacks are performed with the Weather Research and Forecasting (WRF) model. From our investigation, it is evident that subsurface soil temperature feedbacks make a dominant contribution to amplifying summer surface air temperature variability over the arid/semi-arid regions. Further analysis reveals that subsurface soil temperature exhibits an asymmetric effect on summer daytime and nighttime surface air temperature variability, with a stronger effect on daily minimum temperature variability than that of daily maximum temperature variability. This study provides the first RCM-based demonstration that subsurface soil temperature feedbacks play an important role in influencing climate variability over East Asia, such as summer surface air temperature. In the meanwhile, the model bias should be recognized. The results achieved by this study thus need to be further confirmed in a multi-model framework to eliminate the model dependence.

  16. Local versus regional coherence in meteorological variables and lake temperatures

    SciTech Connect

    Benson, B.J.; Kratz, T.K.; Dillon, P. |

    1995-06-01

    Lakes are affected by many driving variables, some acting locally, some regionally. Meteorological variables and lake temperature profiles from long-term data sets collected at four research sites across the Great Lakes Region (the North Temperate Lakes LTER sites in northern and southern Wisconsin, and the Experimental Lakes Area and Dorset Research Area in Canada) were analyzed to test whether inter-annual variation in meteorological variables (air temperature and solar radiation), lake temperature, and mixed layer depth was temporally coherent, i.e. exhibited synchronous variation. Coherence is an important property to evaluate because it influences how broadly we can extrapolate results from a lake or set of lakes and it clarifies what aspects of climate are linked to lake dynamics. Results to date show strong coherence, as measured by high correlation values, of air temperature among the four areas. Summer surface temperature was strongly coherent for lakes within a research site and moderately coherent among some of the sites whereas hypolimnion temperature was not as coherent. Thus lake thermal variables range from being tightly linked to climate to relatively disconnected from regional climatic variation.

  17. Solar-induced 27-day variations of mesospheric temperature and water vapor from the AIM SOFIE experiment: Drivers of polar mesospheric cloud variability

    NASA Astrophysics Data System (ADS)

    Thomas, Gary E.; Thurairajah, Brentha; Hervig, Mark E.; von Savigny, Christian; Snow, Martin

    2015-11-01

    Polar Mesospheric Clouds (PMCs) are known to be influenced by changes in water vapor and temperature in the cold summertime mesopause. Solar variability of these constituents has been held responsible for 11-year and 27-day variability of PMC activity, although the detailed mechanisms are not yet understood. It is also known that the solar influence on PMC variability is a minor contributor to the overall day-to-day variability, which is dominated by effects of gravity waves, planetary waves, and inter-hemispheric coupling. To address this issue, we have analyzed 15 seasons of data taken from the Solar Occultation for Ice Experiment (SOFIE) on the Aeronomy of Ice in the Mesosphere (AIM) satellite. The SOFIE data contain precise measurements of water vapor, temperature and ice water content (among other quantities). These high-latitude measurements are made during the PMC season at the terminator, and therefore directly relate to the simultaneous measurements of mesospheric ice. Using a composite data set of Lyman-α irradiance, we correlated the time variation of the atmospheric variables with the 27-day variability of solar ultraviolet irradiance. We used a combination of time-lagged linear regression and Superposed Epoch Analysis to extract the solar contribution as sensitivity values (response/forcing) vs. height. We compare these results to previously published results, and show that the temperature sensitivity is somewhat higher, whereas the water sensitivity is nearly the same as published values. The time lags are shorter than that expected from direct solar heating and photodissociation, suggesting that the responses are due to 27-day variations of vertical winds. An analytic solution for temperature changes forced by solar irradiance variations suggests that if the response is due purely to Lyman-α heating and Newtonian cooling, the response should vary throughout the summertime season and depend primarily upon the height-dependent column density of

  18. Separation of adsorbed components by variable temperature desorption

    SciTech Connect

    Findley, M.E.

    1990-03-27

    This report covers the activities performed under the Department of Energy grant Separation of Absorbed Components by Variable Temperature Desorption'' to the University of Missouri-Rolla, with Project Director M. E. Findley. This grant is under DOE Energy Related Inventions Program, and originated with the discovery that multicomponent adsorption separations in some cases can be improved by carrying out a thermal desorption at increasing temperatures and separating low temperatures desorbed components from high temperatures desorbed components. The primary objective of this project was to promote the future industrial use of this invention in order to bring about energy savings for the country and if possible profits for the University and the inventors.

  19. Variability of Rotational Temperatures from Different OH Rovibrational Levels

    NASA Astrophysics Data System (ADS)

    Vimal, D. V.; Slanger, T. G.

    2011-12-01

    TThe Meinel band emission lines from rovibrationally excited OH in its electronic ground state in the nightglow are widely used as a diagnostic tool to investigate key mesospheric variables such as temperature, tides, and gravity waves. The OH rotational temperature has been extensively studied to ascertain both long- and short-term variability in the upper atmosphere. Current controversy in the literature regarding the possible variability of temperatures deduced from different OH rovibrational levels limits our ability to compare data from different sources. Researchers tend to use a monitoring vibrational level for OH Meinel bands that is most convenient for their instrument. Background sky spectra captured by astronomical instruments provide detailed records of optical emissions in the upper atmosphere. For this study we utilized existing sky spectra from the Keck telescopes in Mauna Kea and the Very Large Telescope in Chile for the OH Meinel bands bound by the extremes (υ = 3, 8). We compared these results with the temperatures deduced from the O2 0-1 Atmospheric band at 865 nm. This latter emission, emanating from a long-lived species, should represent the true kinetic temperature at the altitude of emission and therefore puts a cap on how high the temperature difference can be between the nominal OH altitude (87 km) and the 95-km altitude of the O2 emission. We present the results of our analysis and discuss the implications for mesospheric temperature retrievals from OH emissions. This work was supported by NSF grant ATM-0924781 from NSF CEDAR.

  20. Ocean versus atmosphere control on western European wintertime temperature variability

    NASA Astrophysics Data System (ADS)

    Yamamoto, Ayako; Palter, Jaime B.; Lozier, M. Susan; Bourqui, Michel S.; Leadbetter, Susan J.

    2015-12-01

    Using a novel Lagrangian approach, we assess the relative roles of the atmosphere and ocean in setting interannual variability in western European wintertime temperatures. We compute sensible and latent heat fluxes along atmospheric particle trajectories backtracked in time from four western European cities, using a Lagrangian atmospheric dispersion model driven with meteorological reanalysis data. The material time rate of change in potential temperature and the surface turbulent fluxes computed along the trajectory show a high degree of correlation, revealing a dominant control of ocean-atmosphere heat and moisture exchange in setting heat flux variability for atmospheric particles en route to western Europe. We conduct six idealised simulations in which one or more aspects of the climate system is held constant at climatological values and these idealised simulations are compared with a control simulation, in which all components of the climate system vary realistically. The results from these idealised simulations suggest that knowledge of atmospheric pathways is essential for reconstructing the interannual variability in heat flux and western European wintertime temperature, and that variability in these trajectories alone is sufficient to explain at least half of the internannual flux variability. Our idealised simulations also expose an important role for sea surface temperature in setting decadal scale variability of air-sea heat fluxes along the Lagrangian pathways. These results are consistent with previous studies showing that air-sea heat flux variability is driven by the atmosphere on interannual time scales over much of the North Atlantic, whereas the SST plays a leading role on longer time scales. Of particular interest is that the atmospheric control holds for the integrated fluxes along 10-day back trajectories from western Europe on an interannual time scale, despite that many of these trajectories pass over the Gulf Stream and its North Atlantic

  1. Variability in Measured Space Temperatures in 60 Homes

    SciTech Connect

    Roberts, D.; Lay, K.

    2013-03-01

    This report discusses the observed variability in indoor space temperature in a set of 60 homes located in Florida, New York, Oregon, and Washington. Temperature data were collected at 15-minute intervals for an entire year, including living room, master bedroom, and outdoor air temperature (Arena, et. al). The data were examined to establish the average living room temperature for the set of homes for the heating and cooling seasons, the variability of living room temperature depending on climate, and the variability of indoor space temperature within the homes. The accuracy of software-based energy analysis depends on the accuracy of input values. Thermostat set point is one of the most influential inputs for building energy simulation. Several industry standards exist that recommend differing default thermostat settings for heating and cooling seasons. These standards were compared to the values calculated for this analysis. The data examined for this report show that there is a definite difference between the climates and that the data do not agree well with any particular standard.

  2. Joint variability of global runoff and global sea surface temperatures

    USGS Publications Warehouse

    McCabe, G.J.; Wolock, D.M.

    2008-01-01

    Global land surface runoff and sea surface temperatures (SST) are analyzed to identify the primary modes of variability of these hydroclimatic data for the period 1905-2002. A monthly water-balance model first is used with global monthly temperature and precipitation data to compute time series of annual gridded runoff for the analysis period. The annual runoff time series data are combined with gridded annual sea surface temperature data, and the combined dataset is subjected to a principal components analysis (PCA) to identify the primary modes of variability. The first three components from the PCA explain 29% of the total variability in the combined runoff/SST dataset. The first component explains 15% of the total variance and primarily represents long-term trends in the data. The long-term trends in SSTs are evident as warming in all of the oceans. The associated long-term trends in runoff suggest increasing flows for parts of North America, South America, Eurasia, and Australia; decreasing runoff is most notable in western Africa. The second principal component explains 9% of the total variance and reflects variability of the El Ni??o-Southern Oscillation (ENSO) and its associated influence on global annual runoff patterns. The third component explains 5% of the total variance and indicates a response of global annual runoff to variability in North Aflantic SSTs. The association between runoff and North Atlantic SSTs may explain an apparent steplike change in runoff that occurred around 1970 for a number of continental regions.

  3. Controls of air temperature variability over an Alpine Glacier

    NASA Astrophysics Data System (ADS)

    Shaw, Thomas; Brock, Ben; Ayala, Álvaro; Rutter, Nick

    2016-04-01

    Near surface air temperature (Ta) is one of the most important controls on energy exchange between a glacier surface and the overlying atmosphere. However, not enough detail is known about the controls on Ta across a glacier due to sparse data availability. Recent work has provided insights into variability of Ta along glacier centre-lines in different parts of the world, yet there is still a limited understanding of off-centreline variability in Ta and how best to estimate it from distant off-glacier locations. We present a new dataset of distributed 2m Ta records for the Tsanteleina Glacier in Northwest Italy from July-September, 2015. Data provide detailed information of lateral (across-glacier) and centre-line variations in Ta, with ~20,000 hourly observations from 17 locations. The suitability of different vertical temperature gradients (VTGs) in estimating air temperature is considered under a range of meteorological conditions and from different forcing locations. A key finding is that local VTGs account for a lot of Ta variability under a broad range of climatic conditions. However, across-glacier variability is found to be significant, particularly for high ambient temperatures and for localised topographic depressions. The relationship of spatial Ta patterns with regional-scale reanalysis data and alternative Ta estimation methodologies are also presented. This work improves the knowledge of local scale Ta variations and their importance to melt modelling.

  4. Novel Dodecaarylporphyrins: Synthesis and Variable Temperature NMR Studies

    SciTech Connect

    Cancilla, Mark; Lebrilla, Carlito; Ma, Jian-Guo; Medforth, Craig J.; Muzzi, Cinzia M.; Shelnutt, John A.; Smith, Kevin M.; Voss, Lisa

    1999-05-05

    An investigation of the synthesis of novel dodecaarylporphyrins using the Suzuki coupling reaction of arylboronic acids with octabromotetraarylporphyrins is reported. Studies of the dynamic properties of these new porphyrins using variable temperature (VT) 1H NMR spectroscopy and molecular mechanics provide interesting insights into their dynamic properties, including the first determination of {beta} aryl rotation in a porphyrin system.

  5. Enhanced temperature variability in high-altitude climate change

    NASA Astrophysics Data System (ADS)

    Ohmura, Atsumu

    2012-12-01

    In the present article, monthly mean temperature at 56 stations assembled in 18 regional groups in 10 major mountain ranges of the world were investigated. The periods of the analysis covered the last 50 to 110 years. The author found that the variability of temperature in climatic time scale tends to increase with altitude in about 65 % of the regional groups. A smaller number of groups, 20 %, showed the fastest change at an intermediate altitude between the peaks (or ridges) and their foot, while the remaining small number of sites, 15 %, showed the largest trends at the foot of mountains. This tendency provides a useful base for considering and planning the climate impact evaluations. The reason for the amplification of temperature variation at high altitudes is traced back to the increasing diabatic processes in the mid- and high troposphere as a result of the cloud condensation. This situation results from the fact that the radiation balance at the earth's surface is transformed more efficiently into latent heat of evaporation rather than sensible heat, the ratio between them being 4 to 1. Variation in the surface evaporation is converted into heat upon condensation into cloud particles and ice crystals in the mid- and high troposphere. Therefore, this is the altitude where the result of the surface radiation change is effectively transferred. Further, the low temperature of the environment amplifies the effect of the energy balance variation on the surface temperature, as a result of the functional shape of Stefan-Boltzmann law. These processes altogether contribute to enhancing temperature variability at high altitudes. The altitude play s an important role in determining the temperature variability, besides other important factors such as topography, surface characteristics, cryosphere/temperature feedback and the frequency and intensity of an inversion. These processes have a profound effect not only on the ecosystem but also on glaciers and permafrost.

  6. Geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppälä, A.; Randall, C. E.; Clilverd, M. A.; Rozanov, E.; Rodger, C. J.

    2009-10-01

    Here we use the ERA-40 and ECMWF operational surface level air temperature data sets from 1957 to 2006 to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the A p index. Previous modeling work has suggested that NO x produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in surface air temperatures (SATs). We find that during winter months, polar SATs in years with high A p index are different than in years with low A p index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, depending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings (SSWs) are excluded. We take into account solar irradiance variations, unlike previous analyses of geomagnetic effects in ERA-40 and operational data. Although we cannot conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. We tested our SAT results against variation in the Quasi Biennial Oscillation, the El Niño Southern Oscillation and the Southern Annular Mode. The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode, and we cannot robustly exclude a chance linkage between sea surface temperature variability and geomagnetic activity.

  7. Temperature variability in a shallow, tidally isolated coral reef lagoon

    NASA Astrophysics Data System (ADS)

    McCabe, R. M.; Estrade, P.; Middleton, J. H.; Melville, W. K.; Roughan, M.; Lenain, L.

    2010-12-01

    Temperature data collected in the shallow, tidally isolated reef flat/lagoon of Lady Elliot Island off Queensland, Australia, show marked variability under solar and tidal forcing. Sea level drops below the height of the protective lagoon rim for a few hours during low tide, effectively isolating the remaining water. Because the lagoon is shallow, its temperature change (from diurnal solar forcing and cooling) is amplified. We develop a simple analytical model to predict the time evolution of mean lagoon temperature, beginning with a well-mixed control volume. This approach highlights the asymmetric flood/ebb physics of tidally isolated lagoons. After discussing the response of this model, we compare it with results from two idealized numerical simulations that illustrate differing aspects of lagoon temperature variability under "potential flow" and "prevailing current" situations. The conceptual model captures the essence of lagoon temperature variability and underscores the importance of solar-lunar phasing. However, because of the well-mixed assumption, it cannot reproduce sudden temperature transitions associated with new incoming water masses. Observations show that a slowly progressing thermal wave inundates the lagoon on rising tides. This wave is similar to our "potential flow" simulation in that it is approximately radially symmetric. On the other hand, it appears to advectively replace resident lagoon water, similar to our "prevailing current" simulations. We attempt to account for this behavior with a simple "frontal" modification to our conceptual model. Results show that this frontal model is able to capture the sudden temperature transitions present in the data and offers improved predictive capabilities over the well-mixed model.

  8. Rheological modelling of physiological variables during temperature variations at rest.

    PubMed

    Vogelaere, P; De Meyer, F

    1990-08-01

    The evolution with time of cardio-respiratory variables, blood pressure and body temperature has been studied on six males, resting in semi-nude conditions during short (30 min) cold stress exposure (0 degree C) and during passive recovery (60 min) at 20 degrees C. Passive cold exposure does not induce a change in HR but increases VO2, VCO2, Ve and core temperature Tre, whereas peripheral temperature is significantly lowered. The kinetic evolution of the studied variables was investigated using a Kelvin-Voigt rheological model. The results suggest that the human body, and by extension the measured physiological variables of its functioning, does not react as a perfect viscoelastic system. Cold exposure induces a more rapid adaptation for heart rate, blood pressure and skin temperatures than that observed during the rewarming period (20 degrees C), whereas respiratory adjustments show an opposite evolution. During the cooling period of the experiment the adaptative mechanisms, taking effect to preserve core homeothermy and to obtain a higher oxygen supply, increase the energy loss of the body. PMID:2228298

  9. Temperature variable long path cell for absorption measurements

    NASA Technical Reports Server (NTRS)

    Shetter, R. E.; Davidson, J. A.; Cantrell, C. A.; Calvert, J. G.

    1987-01-01

    The design and construction of a long path cell for absorption measurements at temperatures ranging from 215-470 K and at pressures from vacuum to 10 atm are described. The cell consists of three concentric stainless-steel tubes; the innermost tube is 6.5-in. in internal diameter, has a volume of about 47 l, and contains White-type optics, six thermocouples, and a gas input tube; and the outermost tube provides a vacuum Dewar around the inner assembly. The optical design and temperature control system for the long path temperature variable cell are examined. The long path cell is applicable for analyzing temperature and pressure dependence of spectra and reaction rates of gases, and the cell has flow and photolysis capabilities for studying transient species and photochemically initiated reactions. A diagram of the cell is provided.

  10. Analysis and interpretation of variabilities in ozone and temperature fields

    NASA Technical Reports Server (NTRS)

    Chandra, S.

    1990-01-01

    The temporal and spatial variabilities were studied of short and long term fluctuations in stratospheric ozone and temperature at various pressure levels using several years of ozone, temperature, and solar flux data from Nimbus 4, Nimbus 7, and SME satellites. Some results are as follows: (1) the solar UV flux and various indices of solar activity indicate a strong period at about 5 months; (2) satellite total ozone observations were analyzed using 17 years of data from the Nimbus 4 BUV and the Nimbus 7 SBUV experiments, which show very similar seasonal variations and quasibiennial oscillation (QBO) with some indication of a 4 year component; and (3) the zonal characteristics of both the ozone and temperature trends were derived from ten years of total ozone and 50 mb temperature based on the Nimbus 7 TOMS measurements and the NMC analyses respectively.

  11. Inter-hemispheric temperature variability over the past millennium

    NASA Astrophysics Data System (ADS)

    Neukom, Raphael; Gergis, Joëlle; Karoly, David J.; Wanner, Heinz; Curran, Mark; Elbert, Julie; González-Rouco, Fidel; Linsley, Braddock K.; Moy, Andrew D.; Mundo, Ignacio; Raible, Christoph C.; Steig, Eric J.; van Ommen, Tas; Vance, Tessa; Villalba, Ricardo; Zinke, Jens; Frank, David

    2014-05-01

    The Earth's climate system is driven by a complex interplay of internal chaotic dynamics and natural and anthropogenic external forcing. Recent instrumental data have shown a remarkable degree of asynchronicity between Northern Hemisphere and Southern Hemisphere temperature fluctuations, thereby questioning the relative importance of internal versus external drivers of past as well as future climate variability. However, large-scale temperature reconstructions for the past millennium have focused on the Northern Hemisphere, limiting empirical assessments of inter-hemispheric variability on multi-decadal to centennial timescales. Here, we introduce a new millennial ensemble reconstruction of annually resolved temperature variations for the Southern Hemisphere based on an unprecedented network of terrestrial and oceanic palaeoclimate proxy records. In conjunction with an independent Northern Hemisphere temperature reconstruction ensemble, this record reveals an extended cold period (1594-1677) in both hemispheres but no globally coherent warm phase during the pre-industrial (1000-1850) era. The current (post-1974) warm phase is the only period of the past millennium where both hemispheres are likely to have experienced contemporaneous warm extremes. Our analysis of inter-hemispheric temperature variability in an ensemble of climate model simulations for the past millennium suggests that models tend to overemphasize Northern Hemisphere-Southern Hemisphere synchronicity by underestimating the role of internal ocean-atmosphere dynamics, particularly in the ocean-dominated Southern Hemisphere. Our results imply that climate system predictability on decadal to century timescales may be lower than expected based on assessments of external climate forcing and Northern Hemisphere temperature variations alone.

  12. Linking geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppala, Annika

    ERA-40 and ECMWF operational surface level air temperature (SAT) data sets from 1957 to 2006 were used to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the Ap index. Previous modelling work has suggested that NOx produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in polar SATs. We find that during winter months, ERA-40 and ECMWF polar SATs in years with high Ap index are different than in years with low Ap index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, de-pending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings are excluded. Solar irradiance variations were taken into account in the analysis. Although using the re-analysis and operational data sets it was not possible to conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating polar wintertime surface air temperature patterns. The SAT results were tested against variation in the Quasi Biennial Oscillation (QBO), the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode n (SAM). The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode (NAM) and we could not robustly exclude a chance linkage between sea surface temperature (SST) variability and geomagnetic activity. Examining the physical link between geomagnetic activity and polar surface temperature variability patterns using atmospheric models is an ongoing task.

  13. Complexation of thorium(IV) with acetate at variable temperatures.

    PubMed

    Rao, Linfeng; Zhang, Zhicheng; Zanonato, PierLuigi; Di Bernardo, Plinio; Bismondo, Arturo; Clark, Sue B

    2004-09-21

    The complexation between Th(IV) and acetate in 1.05 mol kg(-1) NaClO4 was studied at variable temperatures (10, 25, 40, 55 and 70 degrees C). The formation constants of five successive complexes, Th(Ac)j(4-j)+ where Ac = CH3COO- and j = 1-5, and the molar enthalpies of complexation were determined by potentiometry and calorimetry. Extended X-ray absorption fine structure spectroscopy (EXAFS) provided additional information on the complexes in solution. The effect of temperature on the stability of the complexes is discussed in terms of the electrostatic model. PMID:15349159

  14. Potential vorticity intrusion index and climate variability of surface temperature

    NASA Astrophysics Data System (ADS)

    Cai, M.

    2003-04-01

    This paper proposes a potential vorticity intrusion index (denoted as PVI) as an alternative diagnostic tool to study the observed climate variability/trend of the surface temperature. The PVI index is defined as the percentage area of upper lever PV intrusion in the extratropics at any given time. Abundance (shortage) of extreme cold surface air temperature episodes in high latitudes coincides with a high (low) PVI index. The interannual variability of the PVI index exhibits a strong QBO- like signal. The high (low) PVI index prevails when the equatorial zonal mean zonal wind at 50 hPa is easterly (westerly). The probability distribution map of PV intrusion activities shows a shift of the preferred regions of frontogenesis from the oceans to the continents when the PVI index is high. This explains directly why more extreme cold events are observed over the northern Eurasian and Northern America continents when the PVI index is high or the QBO is in the easterly phase.

  15. Potential vorticity intrusion index and climate variability of surface temperature

    NASA Astrophysics Data System (ADS)

    Cai, Ming

    2003-02-01

    This paper proposes a potential vorticity intrusion index (denoted as PVI) as an alternative diagnostic tool to study the observed climate variability/trend of the surface temperature. The PVI index measures the percentage area of upper lever PV intrusion in the extratropics at any given time. More (fewer) outbreaks of extreme cold surface air temperature in high latitudes take place when the PVI index is high (low). The interannual variability of the PVI index exhibits a strong QBO- like signal. The high (low) PVI index prevails when the equatorial zonal mean zonal wind at 50 hPa is easterly (westerly). The probability distribution map of PV intrusion activities shows a shift of the preferred regions of frontogenesis from the oceans to the continents when the PVI index is high. This explains directly why more extreme cold events are observed over the northern Eurasian and Northern America continents when the PVI index is high, or the QBO is in the easterly phase.

  16. Soil temperature variability in complex terrain measured using fiber-optic distributed temperature sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil temperature (Ts) exerts critical controls on hydrologic and biogeochemical processes but magnitude and nature of Ts variability in a landscape setting are rarely documented. Fiber optic distributed temperature sensing systems (FO-DTS) potentially measure Ts at high density over a large extent. ...

  17. Temperature variability and early clustering of record-breaking events

    NASA Astrophysics Data System (ADS)

    Anderson, Amalia; Kostinski, Alex

    2016-05-01

    As the number of climatological studies using record-breaking statistics is growing rapidly, understanding the sensitivity of the chosen time period becomes essential. To that end, here we examine the evolving variability of monthly mean temperatures and its dependence on beginning and final year. Specifically, we use an index, α, based on record-breaking statistics and employing reversibility such that < α>=0 indicates no trend in variability. Generally, < α> has decreased between 1900 and 2013, indicating decreasing variability relative to early decades for stations from the contiguous USA (United States Historical Climatology Network, version 2.5). We find, somewhat surprisingly, that the observed decrease is due to an early excess of records beginning in 1917 (record low value) and 1921 (record high value). While detailed results depend on whether the data is gridded, detrended, etc., the general finding appears remarkably robust and holds globally as well.

  18. Subseasonal variability of North American wintertime surface air temperature

    NASA Astrophysics Data System (ADS)

    Lin, Hai

    2015-09-01

    Using observational pentad data of the recent 34 Northern Hemisphere extended winters, subseasonal variability of surface air temperature (SAT) over North America is analyzed. The four leading modes of subseasonal SAT variability, that are identified with an empirical orthogonal function (EOF) analysis, account for about 60% of the total variance. The first (EOF1) and second (EOF2) modes are independent of other modes, and thus are likely controlled by distinct processes. The third (EOF3) and fourth (EOF4) modes, however, tend to have a phase shift to each other in space and time, indicating that part of their variability is related to a common process and represent a propagating pattern over North America. Lagged regression analysis is conducted to identify the precursors of large-scale atmospheric circulation for each mode a few pentads in advance, and to understand the processes that influence the subseasonal SAT variability and the predictability signal sources. EOF1 is found to be closely related to the Pacific-North American (PNA) circulation pattern and at least part of its variability is preceded by the East Asian cold surge. The cold surge leads to low-level convergence and enhanced convection in the tropical central Pacific which in turn induces the PNA. EOF2 tends to oscillate at a period of about 70 days, and is influenced by the low-frequency component of the Madden-Julian Oscillation (MJO). On the other hand, EOF3 and EOF4 are connected to the high-frequency part of the MJO which has a period range of 30-50 days. These findings would help understanding the mechanisms of subseasonal surface air temperature variability in North America and improving weather predictions on a subseasonal time scale.

  19. Water temperature variability within an Arctic stream; analysis and implications

    NASA Astrophysics Data System (ADS)

    Mellor, C. J.; Hannah, D. M.; Milner, A. M.

    2009-04-01

    Arctic climate warming occurred at twice the global average over the last century and air temperature is predicted to increase by 7.5°C by 2099. Arctic river systems are hypothesized to be particularly vulnerable to warming due to their dependence on cryospheric water sources and thermal sensitivity of biotic communities. However, research is very limited on hydroecological response of Arctic rivers to a changing climate. This paper addresses this research gap and aims to investigate links between thermal dynamics and benthic communities for a river basin in Swedish Lappland. The Kårsavagge is located ~200 km north of the Arctic Circle and contains a small temperate glacier and two lakes. The Kårsa River drains into the Abisko River (~ 25 km from the valley head). The region experiences marked seasonality with average monthly air temperature ranging from +10 to -10°C. In June 2008, three gauging stations (1 - close to glacier snout, 2 - above first major extra glacial tributary and 3 - between the lakes and confluence with the Abisko river) were installed to record water temperature, riverbed temperature (at 0.05m, 0.20m and 0.40m depth), electrical conductivity, river stage, precipitation and turbidity. On top of these, twenty loggers recorded water temperature between gauging stations and across a braided reach located ~ 1.5km downstream of the glacier snout. Diurnal water temperature cycles were found at all sites; but average temperature increased downstream from 1.7°C near the glacier snout to 10.6°C before the Abisko River confluence. Sites immediately downstream of the lakes displayed moderated thermal variability. Bed temperatures in the upper catchment (lower) were higher (lower) and less variable that temperatures in the overlying water column. The degree of parity between water column and stream bed temperatures varied among sites with site 3 showing the greatest difference and site 2 showing the least. This implies a variable degree of

  20. Temperature fluctuations as a source of brown dwarf variability

    SciTech Connect

    Robinson, Tyler D.; Marley, Mark S.

    2014-04-20

    A number of brown dwarfs are now known to be variable with observed amplitudes as large as 10%-30% at some wavelengths. While spatial inhomogeneities in cloud coverage and thickness are likely responsible for much of the observed variability, it is possible that some of the variations arise from atmospheric temperature fluctuations instead of, or in addition to, clouds. To better understand the role that thermal variability might play we present a case study of brown dwarf variability using a newly developed one-dimensional, time-stepping model of atmospheric thermal structure. We focus on the effects of thermal perturbations, intentionally simplifying the problem through omission of clouds and atmospheric circulation. Model results demonstrate that thermal perturbations occurring deep in the atmosphere (at pressures greater than 10 bar) of a model T-dwarf can be communicated to the upper atmosphere through radiative heating via the windows in near-infrared water opacity. The response time depends on where in the atmosphere a thermal perturbation is introduced. We show that, for certain periodic perturbations, the emission spectrum can have complex time- and wavelength-dependent behaviors, including phase shifts in times of maximum flux observed at different wavelengths. Since different wavelengths probe different levels in the atmosphere, these variations track a wavelength-dependent set of radiative exchanges happening between different atmospheric levels as a perturbation evolves in time. We conclude that thermal—as well as cloud—fluctuations must be considered as possible contributors to the observed brown dwarf variability.

  1. Quantifying Walker River stream temperature variability using distributed temperature sensing data

    NASA Astrophysics Data System (ADS)

    Beck, A. J.; Null, S. E.

    2014-12-01

    Nevada's Walker River historically supported Lahontan cutthroat trout (Oncorhynchus clarki henshawi), although today Lahontan cutthroat trout are listed as a federally threatened species and limited to isolated headwater reaches. Much of the lower Walker River is impaired for native aquatic species because of elevated stream temperatures and nutrients, and low streamflow and dissolved oxygen levels. We deployed a 1 kilometer single-ended fiber-optic Raman spectra distributed temperature sensing (DTS) cable in the Wabuska drain outlet and surrounding Walker River for one week in June 2014 to improve fine-scale understanding of stream temperatures. These data identify and quantify thermal variability of micro-habitat that standard temperature monitoring and modeling do not capture. Results indicate stream temperatures exceeded 26°C and a return flow channel exhibited greater thermal variability with both warmer daytime temperatures and cooler nighttime temperatures - possibly providing more complex thermal habitat during some flow conditions. Fine-scale DTS data complement ongoing stream temperature modeling by bounding thermal variability within model reaches that are 250 m long and where stream temperature is assumed to be well-mixed within each reach.

  2. Effect of implant variables on temperatures achieved during ferromagnetic hyperthermia.

    PubMed

    Tompkins, D T; Partington, B P; Steeves, R A; Bartholow, S D; Paliwal, B R

    1992-01-01

    Effects of ferromagnetic implant variables on steady-state temperature were studied in both in vitro (phantom) and in vivo (rabbit hind limb musculature) models. Thermoseed implant variables included: (1) the presence and number of thermoseed sleeves; (2) variations in thermoseed alignment within the oscillating electromagnetic field; (3) generator power levels of 300 W, 600 W, and 1200 W; and (4) separation of thermoseed tracks by 0.8 cm versus 1 cm. When the thermoseeds were aligned parallel to the electromagnetic field, temperature distributions in the in vivo model using bare thermoseeds and thermoseeds encased in a single sleeve (0.1 mm wall thickness) of polyethylene tubing were statistically higher than in tests performed with thermoseeds encased in a double sleeve (0.25 mm over 0.1 mm wall thickness) of tubing (p = 0.006). Nonetheless, average steady-state temperatures above a therapeutic minimum (greater than or equal to 42 degrees C) were achieved at all generator power levels using thermoseeds encased in a double sleeve of tubing and aligned parallel to the electromagnetic field. Gross misalignment of thermoseeds with the electromagnetic field was partly compensated for by utilizing higher generator power levels. Thermoseed tracks separated by 0.8 cm and aligned parallel to the electromagnetic field yielded average steady-state temperatures that were 0.4-2.2 degrees C higher than those obtained with a thermoseed track separation of 1 cm. PMID:1573313

  3. Low vibration high numerical aperture automated variable temperature Raman microscope

    NASA Astrophysics Data System (ADS)

    Tian, Yao; Reijnders, Anjan A.; Osterhoudt, Gavin B.; Valmianski, Ilya; Ramirez, J. G.; Urban, Christian; Zhong, Ruidan; Schneeloch, John; Gu, Genda; Henslee, Isaac; Burch, Kenneth S.

    2016-04-01

    Raman micro-spectroscopy is well suited for studying a variety of properties and has been applied to a wide range of areas. Combined with tuneable temperature, Raman spectra can offer even more insights into the properties of materials. However, previous designs of variable temperature Raman microscopes have made it extremely challenging to measure samples with low signal levels due to thermal and positional instabilities as well as low collection efficiencies. Thus contemporary Raman microscope has found limited applicability to probing the subtle physics involved in phase transitions and hysteresis. This paper describes a new design of a closed-cycle, Raman microscope with full polarization rotation. High collection efficiency, thermal stability, and mechanical stability are ensured by both deliberate optical, cryogenic, and mechanical design. Measurements on two samples, Bi2Se3 and V2O3, which are challenging due to low thermal conductivities, low signal levels, and/or hysteretic effects, are measured with previously undemonstrated temperature resolution.

  4. Low vibration high numerical aperture automated variable temperature Raman microscope.

    PubMed

    Tian, Yao; Reijnders, Anjan A; Osterhoudt, Gavin B; Valmianski, Ilya; Ramirez, J G; Urban, Christian; Zhong, Ruidan; Schneeloch, John; Gu, Genda; Henslee, Isaac; Burch, Kenneth S

    2016-04-01

    Raman micro-spectroscopy is well suited for studying a variety of properties and has been applied to a wide range of areas. Combined with tuneable temperature, Raman spectra can offer even more insights into the properties of materials. However, previous designs of variable temperature Raman microscopes have made it extremely challenging to measure samples with low signal levels due to thermal and positional instabilities as well as low collection efficiencies. Thus contemporary Raman microscope has found limited applicability to probing the subtle physics involved in phase transitions and hysteresis. This paper describes a new design of a closed-cycle, Raman microscope with full polarization rotation. High collection efficiency, thermal stability, and mechanical stability are ensured by both deliberate optical, cryogenic, and mechanical design. Measurements on two samples, Bi2Se3 and V2O3, which are challenging due to low thermal conductivities, low signal levels, and/or hysteretic effects, are measured with previously undemonstrated temperature resolution. PMID:27131652

  5. Trends and variability in East African rainfall and temperature observations

    NASA Astrophysics Data System (ADS)

    Seregina, Larisa; Ermert, Volker; Fink, Andreas H.; Pinto, Joaquim G.

    2014-05-01

    The economy of East Africa is highly dependent on agriculture, leading to a strong vulnerability of local society to fluctuations in seasonal rainfall amounts, including extreme events. Hence, the knowledge about the evolution of seasonal rainfall under future climate conditions is crucial. Rainfall regimes over East Africa are influenced by multiple factors, including two monsoon systems, several convergence zones and the Rift Valley lakes. In addition, local conditions, like topography, modulate the large-scale rainfall pattern. East African rainfall variability is also influenced by various teleconnections like the Indian Ocean Zonal Mode and El Niño Southern Oscillation. Regarding future climate projections, regional and global climate models partly disagree on the increase or decrease of East African rainfall. The specific aim of the present study is the acquirement of historic data from weather stations in East Africa (Kenya, Tanzania, Ruanda and Uganda), the use of gridded satellite (rainfall) products (ARC2 and TRMM), and three-dimensional atmospheric reanalysis (e.g., ERA-Interim) to quantify climate variability in the recent past and to understand its causes. Climate variability and trends, including changes in extreme events, are evaluated using ETCCDI climate change and standardized precipitation indices. These climate indices are determined in order to investigate the variability of temperature and rainfall and their trends with the focus on most recent decades. In the follow-up, statistical and dynamical analyses are conducted to quantify the local impact of pertinent large-scale modes of climate variability (Indian Ocean Zonal Mode, El Niño Southern Oscillation, Sea Surface Temperature of the Indian Ocean).

  6. Bottom temperature and salinity distribution and its variability around Iceland

    NASA Astrophysics Data System (ADS)

    Jochumsen, Kerstin; Schnurr, Sarah M.; Quadfasel, Detlef

    2016-05-01

    The barrier formed by the Greenland-Scotland-Ridge (GSR) shapes the oceanic conditions in the region around Iceland. Deep water cannot be exchanged across the ridge, and only limited water mass exchange in intermediate layers is possible through deep channels, where the flow is directed southwestward (the Nordic Overflows). As a result, the near-bottom water masses in the deep basins of the northern North Atlantic and the Nordic Seas hold major temperature differences. Here, we use near-bottom measurements of about 88,000 CTD (conductivity-temperature-depth) and bottle profiles, collected in the period 1900-2008, to investigate the distribution of near-bottom properties. Data are gridded into regular boxes of about 11 km size and interpolated following isobaths. We derive average spatial temperature and salinity distributions in the region around Iceland, showing the influence of the GSR on the near-bottom hydrography. The spatial distribution of standard deviation is used to identify local variability, which is enhanced near water mass fronts. Finally, property changes within the period 1975-2008 are presented using time series analysis techniques for a collection of grid boxes with sufficient data resolution. Seasonal variability, as well as long term trends are discussed for different bottom depth classes, representing varying water masses. The seasonal cycle is most pronounced in temperature and decreases with depth (mean amplitudes of 2.2 °C in the near surface layers vs. 0.2 °C at depths > 500 m), while linear trends are evident in both temperature and salinity (maxima in shallow waters of +0.33 °C/decade for temperature and +0.03/decade for salinity).

  7. Infrared-temperature variability in a large agricultural field

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Goettelman, R. C.; Leroy, M. J.

    1981-01-01

    Dunnigan Agro-Meteorological Experiment airborne thermal scanner images of a large varying-terrain barley field are acquired and analyzed. Temperature variability that may occur within instantaneous fields of view (IFOV) is defined (coefficient of variation: standard deviation/mean temperature in degrees C), and the percentage of the area within various IFOV's within + or - 1, 2, 3, and 5 degrees of the mean is determined. With the exception of very rugged terrain, over 80% of the area within 4, 16, 65 and 258 ha cells was at temperatures within + or - 3 C of the mean cell temperature. Remote measurements of field temperature appeared to be slightly influenced by pixel size in the range 4 ha to 259 ha, and the area percentage within any pixel which contributes within + or - 1, 2, 3, and 5 degrees C of the mean, is nominally the same. In conclusion, no great advantage is found in utilizing a small IFOV instead of a large one for remote sensing of crop temperature.

  8. Implementation of Temperature Sequential Controller on Variable Speed Drive

    NASA Astrophysics Data System (ADS)

    Cheong, Z. X.; Barsoum, N. N.

    2008-10-01

    There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

  9. Identifying Modes of Temperature Variability Using AIRS Data.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.; Yung, Y.

    2007-12-01

    We use the Atmospheric Infrared Sounder (AIRS) and Advance Microwave Sounding Unit (AMSU) data obtained on Aqua spacecraft to study mid-tropospheric temperature variability between 2002-2007. The analysis is focused on daily zonal means of the AIRS channel at 2388 1/cm in the CO2 R-branch and the AMSU channel #5 in the 57 GHz Oxygen band, both with weighting function peaking in the mid-troposphere (400 mb) and the matching sea surface temperature from NCEP (Aumann et al., 2007). Taking into account the nonlinear and non- stationary behavior of the temperature we apply the Empirical Mode Decomposition (Huang et al., 1998) to better separate modes of variability. All-sky (cloudy) and clear sky, day and night data are analyzed. In addition to the dominant annual variation, which is nonlinear and latitude dependent, we identified the modes with higher frequency and inter-annual modes. Some trends are visible and we apply stringent criteria to test their statistical significance. References: Aumann, H. H., D. T. Gregorich, S. E. Broberg, and D. A. Elliott, Geophys. Res. Lett., 34, L15813, doi:10.1029/2006GL029191, 2007. Huang, N. E. Z. Shen, S. R. Long, M. C. Wu, H. H. Shih, Q. Zheng, N.-C. Yen, C. C. Tung, and H. H. Liu, Proc. R. Soc. Lond., A 454, 903-995, 1998.

  10. Statistical attribution of temporal variability in global gridded temperature data

    NASA Astrophysics Data System (ADS)

    Pisoft, P.; Miksovsky, J.

    2015-12-01

    Spatiotemporal variability within the climate system results from a complex interaction of various exogenous and endogenous factors, yet the understanding of the specific role of individual climate-forming agents is still incomplete. In this contribution, near-surface monthly temperature anomalies from several gridded datasets (GISTEMP, Berkeley Earth, MLOST, HadCRUT4, 20th Century Reanalysis) are investigated for presence of components attributable to external forcings (anthropogenic, solar and volcanic) as well as to internal forcings related to major climate variability modes (El Niño / Southern Oscillation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation). Statistical methodology based on multiple linear regression is employed, and applied to monthly temperature data for the 1901-2010 period. The results presented illustrate the spatial fingerprints of individual forcing factors and their robustness (or lack thereof) among individual temperature datasets. Particular attention is devoted to the specific features of the 20th Century Reanalysis: It is demonstrated that while most of the response patterns are represented similarly in the reanalysis data and in their analysis-type counterparts, some distinctions appear, especially for the components associated with anthropogenic forcing and volcanic activity.

  11. Beyond extreme temperatures: soil water supply and yield variability

    NASA Astrophysics Data System (ADS)

    Urban, D.; Lobell, D. B.

    2014-12-01

    Extreme weather events have profound consequences for both the mean and interannual variability of agricultural production, but while the role of extreme heat has been convincingly demonstrated, soil water supply has received less attention. In particular, there is debate over the extent to which damages attributed to extreme heat are confounded with drought conditions. In a pair of studies, we examine the effect of extreme moisture conditions, both wet and dry, on maize and soybean yields in the U.S. We find significant effects of waterlogging during the planting season, when crops are most vulnerable to excess moisture, as well as evidence for a strong interaction between high temperatures and low moisture during during the critical stages of the summer growing season. Using both precipitation and model-derived soil moisture data, our results suggest that considering temperature and moisture independently will underestimate yield damages during hot, dry conditions. Many warming scenarios project increases in both extreme summer temperatures and soil dryness, and considering these effects jointly can be important in estimating future yield variability.

  12. Anisotropic high temperature superconductors as variable resistors and switches

    SciTech Connect

    Boenig, H.J.; Daugherty, M.A.; Fleshler, S.; Maley, M.P.; Mueller, F.M.; Prenger, F.C.; Coulter, J.Y.

    1994-12-01

    Several anisotropic high temperature superconductors show critical current densities which are strongly dependent on the direction of an applied external magnetic field. The resistance of a sample can change by several orders of magnitude by applying a magnetic field. The potential for using the field dependent variable resistor or switch for applications in power systems is evaluated. Test results with small samples are presented. The requirements for large scale applications are outlined. The magnetic field triggering requirement, the frequency response of the device, use in 60 Hz ac circuits and heat transfer consideration are investigated. Several application examples are discussed. Use of variable resistor as a fault current limiter, as a switching element in rectifier circuitry and as an improved dump resistor for a superconducting magnet is presented.

  13. Variability of surface temperature in agricultural fields of central California

    NASA Technical Reports Server (NTRS)

    Hatfield, J. L.; Millard, J. P.; Goettelman, R. C.

    1982-01-01

    In an attempt to evaluate the relationship between hand-held infrared thermometers and aircraft thermal scanners in near-level terrain and to quantify the variability of surface temperatures within individual fields, ground-based and aircraft thermal sensor measurements were made along a 50-km transect on 3 May 1979 and a 20-km transect on 7 August 1980. These comparisons were made on fields near Davis, California. Agreement was within 1 C for fields covered with vegetation and 3.6 C for bare, dry fields. The variability within fields was larger for bare, dry fields than for vegetatively covered fields. In 1980, with improvements in the collection of ground truth data, the agreement was within 1 C for a variety of fields.

  14. Variability of Battery Wear in Light Duty Plug-In Electric Vehicles Subject to Ambient Temperature, Battery Size, and Consumer Usage: Preprint

    SciTech Connect

    Wood, E.; Neubauer, J.; Brooker, A. D.; Gonder, J.; Smith, K. A.

    2012-08-01

    Battery wear in plug-in electric vehicles (PEVs) is a complex function of ambient temperature, battery size, and disparate usage. Simulations capturing varying ambient temperature profiles, battery sizes, and driving patterns are of great value to battery and vehicle manufacturers. A predictive battery wear model developed by the National Renewable Energy Laboratory captures the effects of multiple cycling and storage conditions in a representative lithium chemistry. The sensitivity of battery wear rates to ambient conditions, maximum allowable depth-of-discharge, and vehicle miles travelled is explored for two midsize vehicles: a battery electric vehicle (BEV) with a nominal range of 75 mi (121 km) and a plug-in hybrid electric vehicle (PHEV) with a nominal charge-depleting range of 40 mi (64 km). Driving distance distributions represent the variability of vehicle use, both vehicle-to-vehicle and day-to-day. Battery wear over an 8-year period was dominated by ambient conditions for the BEV with capacity fade ranging from 19% to 32% while the PHEV was most sensitive to maximum allowable depth-of-discharge with capacity fade ranging from 16% to 24%. The BEV and PHEV were comparable in terms of petroleum displacement potential after 8 years of service, due to the BEV?s limited utility for accomplishing long trips.

  15. Variability of Winter Air Temperature in Mid-Latitude Europe

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

    2002-01-01

    The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

  16. Complexation of Plutonium (IV) With Sulfate At Variable Temperatures

    SciTech Connect

    Y. Xia; J.I. Friese; D.A> Moore; P.P. Bachelor; L. Rao

    2006-10-05

    The complexation of plutonium(IV) with sulfate at variable temperatures has been investigated by solvent extraction method. A NaBrO{sub 3} solution was used as holding oxidant to maintain the plutonium(IV) oxidation state throughout the experiments. The distribution ratio of Pu(IV) between the organic and aqueous phases was found to decrease as the concentrations of sulfate were increased. Stability constants of the 1:1 and 1:2 Pu(IV)-HSO{sub 4}{sup -} complexes, dominant in the aqueous phase, were calculated from the effect of [HSO{sub 4}{sup -}] on the distribution ratio. The enthalpy and entropy of complexation were calculated from the stability constants at different temperatures using the Van't Hoff equation.

  17. Stochastic investigation of temperature process for climatic variability identification

    NASA Astrophysics Data System (ADS)

    Lerias, Eleutherios; Kalamioti, Anna; Dimitriadis, Panayiotis; Markonis, Yannis; Iliopoulou, Theano; Koutsoyiannis, Demetris

    2016-04-01

    The temperature process is considered as the most characteristic hydrometeorological process and has been thoroughly examined in the climate-change framework. We use a dataset comprising hourly temperature and dew point records to identify statistical variability with emphasis on the last period. Specifically, we investigate the occurrence of mean, maximum and minimum values and we estimate statistical properties such as marginal probability distribution function and the type of decay of the climacogram (i.e., mean process variance vs. scale) for various time periods. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

  18. Assessing surface air temperature variability using quantile regression

    NASA Astrophysics Data System (ADS)

    Timofeev, A. A.; Sterin, A. M.

    2014-12-01

    Many researches in climate change currently involve linear trends, based on measured variables. And many of them only consider trends in mean values, whereas it is clear, that not only means, but also whole shape of distribution changes over time and requires careful assessment. For example extreme values including outliers may get bigger, while median has zero slope.Quantile regression provides a convenient tool, that enables detailed analysis of changes in full range of distribution by producing a vector of quantile trends for any given set of quantiles.We have applied quantile regression to surface air temperature observations made at over 600 weather stations across Russian Federation during last four decades. The results demonstrate well pronounced regions with similar values of significant trends in different parts of temperature value distribution (left tail, middle part, right tail). The uncertainties of quantile trend estimations for several spatial patterns of trends over Russia are estimated and analyzed for each of four seasons.For temperature trend estimation over vast territories, quantile regression is an effort consuming approach, but is more informative than traditional instrument, to assess decadal evolution of temperature values, including evolution of extremes.Partial support of ERA NET RUS ACPCA joint project between EU and RBRF 12-05-91656-ЭРА-А is highly appreciated.

  19. Predictability of Mediterranean climate variables from oceanic variability. Part I: Sea surface temperature regimes

    NASA Astrophysics Data System (ADS)

    Hertig, E.; Jacobeit, J.

    2011-03-01

    The determination of specific sea surface temperature (SST) patterns from large-scale gridded SST-fields has widely been done. Often principal component analysis (PCA) is used to condense the SST-data to major patterns of variability. In the present study SST-fields for the period 1950-2003 from the area 20°S to 60°N are analysed with respect to SST-regimes being defined as large-scale oceanic patterns with a regular and at least seasonal occurrence. This has been done in context of investigations on seasonal predictability of Mediterranean regional climate with large-scale SST-regimes as intended predictors in statistical model relationships. The SST-regimes are derived by means of a particular technique including multiple applications of s-mode PCA. Altogether 17 stationary regimes can be identified, eight for the Pacific Ocean, five for the Atlantic Ocean, two for the Indian Ocean, and two regimes which show a distinct co-variability within different ocean basins. Some regimes exist, with varying strength and spatial extent, throughout the whole year, whereas other regimes are only characteristic for a particular season. Several regimes show dominant variability modes, like the regimes associated with El Niño, with the Pacific Decadal Oscillation or with the North Atlantic Tripole, whereas other regimes describe little-known patterns of large-scale SST variability. The determined SST-regimes are subsequently used as predictors for monthly precipitation and temperature in the Mediterranean area. This subject is addressed in Part II of this paper.

  20. Variable temperature thin film indentation with a flat punch.

    PubMed

    Cross, Graham L W; O'Connell, Barry S; Pethica, John B; Rowland, Harry; King, William P

    2008-01-01

    We present modifications to conventional nanoindentation that realize variable temperature, flat punch indentation of ultrathin films. The technique provides generation of large strain, thin film extrusion of precise geometries that idealize the essential flows of nanoimprint lithography, and approximate constant area squeeze flow rheometry performed on thin, macroscopic soft matter samples. Punch radii as small as 185 nm have been realized in ten-to-one confinement ratio testing of 36 nm thick polymer films controllably squeezed in the melt state to a gap width of a few nanometers. Self-consistent, compressive stress versus strain measurements of a wide variety of mechanical testing conditions are provided by using a single die-sample system with temperatures ranging from 20 to 125 degrees C and loading rates spanning two decades. Low roughness, well aligned flat punch dies with large contact areas provide precise detection of soft surfaces with standard nanoindenter stiffness sensitivity. Independent heating and thermometry with heaters and thermocouples attached to the die and sample allow introduction of a novel directional heat flux measurement method to ensure isothermal contact conditions. This is a crucial requirement for interpreting the mechanical response in temperature sensitive soft matter systems. Instrumented imprint is a new nanomechanics material testing platform that enables measurements of polymer and soft matter properties during large strains in confined, thin film geometries and extends materials testing capabilities of nanoindentation into low modulus, low strength glassy, and viscoelastic materials. PMID:18248047

  1. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-01-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling convertor. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 C while the heat losses caused by the addition of the VCHP are 1.8 W.

  2. Low vibration high numerical aperture automated variable temperature Raman microscope

    DOE PAGESBeta

    Tian, Y.; Reijnders, A. A.; Osterhoudt, G. B.; Valmianski, I.; Ramirez, J. G.; Urban, C.; Zhong, R.; Schneeloch, J.; Gu, G.; Henslee, I.; et al

    2016-04-05

    Raman micro-spectroscopy is well suited for studying a variety of properties and has been applied to wide- ranging areas. Combined with tuneable temperature, Raman spectra can offer even more insights into the properties of materials. However, previous designs of variable temperature Raman microscopes have made it extremely challenging to measure samples with low signal levels due to thermal and positional instability as well as low collection efficiencies. Thus, contemporary Raman microscope has found limited applicability to probing the subtle physics involved in phase transitions and hysteresis. This paper describes a new design of a closed-cycle, Raman microscope with full polarizationmore » rotation. High collection efficiency, thermal and mechanical stability are ensured by both deliberate optical, cryogenic, and mechanical design. Measurements on two samples, Bi2Se3 and V2O3, which are known as challenging due to low thermal conductivities, low signal levels and/or hysteretic effects, are measured with previously undemonstrated temperature resolution.« less

  3. Spatial and Seasonal Variability of Extreme Soil Temperature in Croatia

    NASA Astrophysics Data System (ADS)

    Sviličić, Petra; Vučetić, Višnja

    2015-04-01

    In terms of taking the temperature of the Earth in Croatia, first measurements began in 1898 in Križevci, but systematic measurements of soil temperature started in 1951. Today, the measurements are performed at 55 meteorological stations. The process of setting up, calibration, measurement, input, control and data processing is done entirely within the Meteorological and Hydrological Service. Due to the lack of funds, but also as a consequence of the Homeland War, network density in some areas is very rare, leading to aggravating circumstances during analysis. Also, certain temperature series are incomplete or are interrupted and therefore the number of long-term temperature series is very small. This particularly presents problems in coastal area, which is geographically diversified and is very difficult to do a thorough analysis of the area. Using mercury angle geothermometer daily at 7, 14 and 21 h CET, thermal state of soil is measured at 2, 5, 10, 20, 30, 50 and 100 cm depth. Thermometers are placed on the bare ground within the meteorological circle and facing north to reduce the direct impact of solar radiation. Lack of term measurements is noticed in the analysis of extreme soil temperatures, which are not real extreme values, but derived from three observational times. On the basis of fifty year series (1961-2010) at 23 stations, the analysis of trends of the surface maximal and minimal soil temperature, as well as the appearance of freezing is presented. Trends were determined by Sen's slope estimator, and statistical significance on 5% level was determined using the Mann-Kendall test. It was observed that the variability of the surface maximal soil temperature on an annual and seasonal level is much higher than those for surface minimal soil temperature. Trends in the recent period show a statistically significant increase in the maximal soil temperature in the eastern and the coastal regions, especially in the spring and summer season. Also, the

  4. Hydrolysis of thorium(iv) at variable temperatures.

    PubMed

    Zanonato, P L; Di Bernardo, P; Zhang, Z; Gong, Y; Tian, G; Gibson, J K; Rao, L

    2016-08-01

    Hydrolysis of Th(iv) was studied in tetraethylammonium perchlorate (0.10 mol kg(-1)) at variable temperatures (283-358 K) by potentiometry and microcalorimetry. Three hydrolysis reactions, mTh(4+) + nH2O = Thm(OH)n((4m-n)+) + nH(+), in which (n,m) = (2,2), (8,4), and (15,6), were invoked to describe the potentiometric and calorimetric data for solutions with the [hydroxide]/[Th(iv)] ratio ≤ 2. At higher ratios, the formation of (16,5) cannot be excluded. The hydrolysis constants, *β2,2, *β8,4, and *β15,6, increased by 3, 7, and 11 orders of magnitude, respectively, as the temperature was increased from 283 to 358 K. The enhancement is mainly due to the significant increase of the degree of ionization of water as the temperature rises. All three hydrolysis reactions are endothermic at 298 K, with enthalpies of (118 ± 4) kJ mol(-1), (236 ± 7) kJ mol(-1), and (554 ± 4) kJ mol(-1) for ΔH2,2, ΔH8,4, and ΔH15,6 respectively. The hydrolysis constants at infinite dilution have been obtained with the specific ion interaction approach. The applicability of three approaches for estimating the equilibrium constants at different temperatures, including the constant enthalpy approach, the constant heat capacity approach and the DQUANT equation was evaluated with the data from this work. PMID:27460458

  5. Soil Temperature Variability in Complex Terrain measured using Distributed a Fiber-Optic Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Seyfried, M. S.; Link, T. E.

    2013-12-01

    Soil temperature (Ts) exerts critical environmental controls on hydrologic and biogeochemical processes. Rates of carbon cycling, mineral weathering, infiltration and snow melt are all influenced by Ts. Although broadly reflective of the climate, Ts is sensitive to local variations in cover (vegetative, litter, snow), topography (slope, aspect, position), and soil properties (texture, water content), resulting in a spatially and temporally complex distribution of Ts across the landscape. Understanding and quantifying the processes controlled by Ts requires an understanding of that distribution. Relatively few spatially distributed field Ts data exist, partly because traditional Ts data are point measurements. A relatively new technology, fiber optic distributed temperature system (FO-DTS), has the potential to provide such data but has not been rigorously evaluated in the context of remote, long term field research. We installed FO-DTS in a small experimental watershed in the Reynolds Creek Experimental Watershed (RCEW) in the Owyhee Mountains of SW Idaho. The watershed is characterized by complex terrain and a seasonal snow cover. Our objectives are to: (i) evaluate the applicability of fiber optic DTS to remote field environments and (ii) to describe the spatial and temporal variability of soil temperature in complex terrain influenced by a variable snow cover. We installed fiber optic cable at a depth of 10 cm in contrasting snow accumulation and topographic environments and monitored temperature along 750 m with DTS. We found that the DTS can provide accurate Ts data (+/- .4°C) that resolves Ts changes of about 0.03°C at a spatial scale of 1 m with occasional calibration under conditions with an ambient temperature range of 50°C. We note that there are site-specific limitations related cable installation and destruction by local fauna. The FO-DTS provide unique insight into the spatial and temporal variability of Ts in a landscape. We found strong seasonal

  6. Picosecond and steady state, variable intensity and variable temperature emission spectroscopy of bacteriorhodopsin.

    PubMed Central

    Shapiro, S L; Campillo, A J; Lewis, A; Perreault, G J; Spoonhower, J P; Clayton, R K; Stoeckenius, W

    1978-01-01

    The bacteriorhodopsin emission lifetime at 77 degrees K has been obtained for different regions of the emission spectrum with single-pulse excitation. The data under all conditions yield a lifetime of 60 +/- 15 ps. Intensity effects on this lifetime have been ruled out by studying the relative emission amplitude as a function of the excitation pulse energy. We relate our lifetime to previously reported values at other temperatures by studying the relative emission quantum efficiency as a function of temperature. These variable temperature studies have indicated that an excited state with an emission maximum at 670 nm begins to contribute to the spectrum as the temperature is lowered. Within our experimental error the picosecond data seem to suggest that this new emission may arise from a minimum of the same electronic state responsible for the 77 degrees K emission at 720 nm. A correlation is noted between a 1.0-ps formation time observed in absorption by Ippen et al. (Ippen, E.P., C.V. Shank, A. Lewis, and M.A. Marcus. 1978. Subpicosecond spectroscopy of bacteriorhodopsin. Science [wash. D.C.]. 200:1279-1281 and a time extrapolated from relative quantum efficiency measurements and the 77 degrees K fluorescence lifetime that we report. Images FIGURE 3 PMID:698343

  7. Amplification of surface temperature trends and variability in thetropical atmosphere

    SciTech Connect

    Santer, B.D.; Wigley, T.M.L.; Mears, C.; Wentz, F.J.; Klein,S.A.; Seidel, D.J.; Taylor, K.E.; Thorne, P.W.; Wehner, M.F.; Gleckler,P.J.; Boyle, J.S.; Collins, W.D.; Dixon, K.W.; Doutriaux, C.; Free, M.; Fu, Q.; Hansen, J.E.; Jones, G.S.; Ruedy, R.; Karl, T.R.; Lanzante, J.R.; Meehl, G.A.; Ramaswamy, V.; Russell, G.; Schmidt, G.A.

    2005-08-11

    The month-to-month variability of tropical temperatures is larger in the troposphere than at the Earth's surface. This amplification behavior is similar in a range of observations and climate model simulations, and is consistent with basic theory. On multi-decadal timescales, tropospheric amplification of surface warming is a robust feature of model simulations, but occurs in only one observational dataset. Other observations show weak or even negative amplification. These results suggest that either different physical mechanisms control amplification processes on monthly and decadal timescales, and models fail to capture such behavior, or (more plausibly) that residual errors in several observational datasets used here affect their representation of long-term trends.

  8. Sea surface temperature variability in the Colombian Basin, Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Ruiz-Ochoa, Mauricio; Beier, Emilio; Bernal, Gladys; Barton, Eric Desmond

    2012-06-01

    Daily sea surface temperature (SST) data from the Advanced Very High Resolution Radiometer (AVHRR) database with ∼4 km of spatial resolution were analyzed for the period 1985-2009 in the Colombian Basin using harmonic and empirical orthogonal function (EOF) analysis. The data were compared with observational records in the Rosario Island National Park at 10 m depth (T10) from March 2003 to August 2005. SST values were higher than T10 from June to October (rainy season), but similar from December to February (dry season); both data sets have similar coefficient of variation. The mean SST distribution varies spatially, with minimum SST values in the coastal zone of La Guajira Peninsula and maximum values in the Darien and Mosquitos Gulfs. The seasonal variability explains up to 75% of the total variability in La Guajira, a high value compared with 40% in the Mosquitos Gulf. The most important feature of the splitting of SST variation into annual and semiannual harmonics in La Guajira is the relationship between their amplitudes. These are of the same order, which is not common in other ocean zones, where the semiannual component is only a small fraction of the annual dominated by the solar warming. The river water discharge, highest from August to November, produces low density surface water, reduces vertical mixing and limits the absorption of solar radiation to a thin surface layer, explaining the discrepancy between SST and T10 in the rainy season. The decomposition of the SST in EOFs indicated that the dominant mode of the basin is a uniform interannual variation in phase with the North Tropical Atlantic Index. The second mode, representing the variability of the Guajira upwelling, covaried strongly with the second mode of wind stress curl. The third mode reflected the role of the vertical atmospheric circulation cell associated with the Caribbean Low Level Jet off Central America.

  9. Forcing, feedback and internal variability in global temperature trends.

    PubMed

    Marotzke, Jochem; Forster, Piers M

    2015-01-29

    Most present-generation climate models simulate an increase in global-mean surface temperature (GMST) since 1998, whereas observations suggest a warming hiatus. It is unclear to what extent this mismatch is caused by incorrect model forcing, by incorrect model response to forcing or by random factors. Here we analyse simulations and observations of GMST from 1900 to 2012, and show that the distribution of simulated 15-year trends shows no systematic bias against the observations. Using a multiple regression approach that is physically motivated by surface energy balance, we isolate the impact of radiative forcing, climate feedback and ocean heat uptake on GMST--with the regression residual interpreted as internal variability--and assess all possible 15- and 62-year trends. The differences between simulated and observed trends are dominated by random internal variability over the shorter timescale and by variations in the radiative forcings used to drive models over the longer timescale. For either trend length, spread in simulated climate feedback leaves no traceable imprint on GMST trends or, consequently, on the difference between simulations and observations. The claim that climate models systematically overestimate the response to radiative forcing from increasing greenhouse gas concentrations therefore seems to be unfounded. PMID:25631444

  10. -30° C to 960° C Variable Temperature Blackbody (VTBB) Radiance Temperature Calibration Facility

    NASA Astrophysics Data System (ADS)

    Yuan, Z.; Wang, J.; Hao, X.; Wang, T.; Dong, W.

    2015-12-01

    A blackbody radiance temperature calibration facility (RTCF) has recently been established at the National Institute of Metrology, China, offering calibration and verification services for variable temperature blackbody (VTBB) radiation sources. The RTCF includes reference VTBBs in the range of -30° C to 960° C and consists of a stirred liquid bath blackbody of -30° C to 80° C and water, cesium, and sodium heat-pipe blackbodies spanning 50° C to 960° C. In addition, the facility is equipped with a set of radiation thermometers with different working wavelengths (or wavebands); these thermometers are used to transfer radiance temperatures from the reference to customers' VTBBs. Cavities with V-notch grooves in the inner surface have an estimated emissivity from 0.99986 to 0.99994. The temperature control stability and temperature uniformity of VTBBs are characterized. Furthermore, we test the difference between a cavity and thermometer well temperatures and compare the radiance temperatures of the Cs and Na heat-pipe blackbodies. The expanded uncertainty (k = 2) of VTBBs' radiance temperatures at 10 \\upmu m (8 \\upmu m to 14 \\upmu m) is evaluated from 0.016° C to 0.23° C. The facility has been used to calibrate and characterize customers' VTBBs.

  11. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    SciTech Connect

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-03-16

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 deg. C while the heat losses caused by the addition of the VCHP are 1.8 W.

  12. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Astrophysics Data System (ADS)

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-03-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140° C while the heat losses caused by the addition of the VCHP are 1.8 W.

  13. Resonance and Variable Temperature Raman Studies of Chloroperoxidase and Methemoglobin.

    NASA Astrophysics Data System (ADS)

    Remba, Ronald David

    1980-12-01

    ) as a function of temperature. This is the first study where the marker band technique is used to measure quantitatively spin transitions. For hydroxide and cyanate methemoglobin, log(I(,h)/I(,1)) varies linearly with 1/T, indicating a high-spin/low-spin thermal equilibrium. The data are analyzed to extract enthalpic and entropic changes. (DELTA)H values from Raman and static magnetic susceptibility techniques show good agreement. (DELTA)S values for horse hydroxide methemoglobin also agree. However, for cyanate methemoglobin, Raman and susceptibility (DELTA)S values differ substantially. Other evidence (ESR, optical, etc.) supports the Raman result. The discrepancy is probably due to the effects of freezing on the protein solution. Other methemoglobins show a discontinuity in the Raman intensity ratio at the freezing transition indicating a non-equilibrium situation where the freezing process drives the spin transition. Effects of freezing the protein solution on the spin transition are discussed. Both the high-spin and low-spin Raman frequencies are observed to remain constant (within (+OR-) 2 cm('-1)) when the temperature is varied. This is discussed in terms of core expansion and heme deformation. Experimental (DELTA)S values are much larger than the spin-only value. This is discussed in terms of a linear temperature dependence on the energy gap between the ('2)T(,2) ground state and the ('6)A(,1) first excited state. Variable temperature Raman data for carp azide methemoglobin with and without IHP indicate that the free energy for the spin transition decreases by 0.6 (+OR-) 0.3 kcal/mole when hemoglobin quaternary structure changes from R to T. Lack of any frequency shift in either the high-spin or low-spin Raman band upon addition of IHP is consistent with other evidence indicating no iron movement upon conversion of R to T quaternary forms.

  14. A High Temperature Hermetic Primer and a Variable Spring Tester

    SciTech Connect

    Begeal, D.R.

    1994-05-01

    Percussion primers are used at Sandia to ignite energetic components such as pyrotechnic actuators and thermal batteries. This report describes a High Temperature Hermetic Primer (HTHP) that was developed to replace a previous G16 Percussion Primer Subassembly (Gl6PPS). The ignition mix in these primers is the same as in the discontinued Remington 44G16 (KC1O{sub 3}, SbS{sub 3}, and Ca{sub 2}Si). The HTHP has nearly the same sensitivity as the 44G16 and a significantly lower sensitivity than the G16PPS. In parallel with the HTHP development, we also designed a Variable Spring Tester (VST) to determine percussion primer ignition sensitivity with firing pins that have the same mass as those used in field applications. The tester is capable of accelerating firing pins over a velocity range of 100 to 600 inches per second for pins weighing up to 6 grams. The desired impulse can be preselected with an accuracy of better than {plus_minus}1%. The actual impulse is measured on every shot. The VST was characterized using the WW42Cl primer, as well as with the G16PPS and the HTHP. Compared to data from conventional ball drop testers, we found that ignition sensitivities were lower and there was less scatter in the sensitivity data. Our experiments indicate that ignition sensitivity is not strictly energy dependent, but also depends on the rate of deposition, or firing pin velocity in this case. Development results for the HTHP and Variable Spring Tester are discussed and design details are shown.

  15. Decadal modulation of global surface temperature by internal climate variability

    NASA Astrophysics Data System (ADS)

    Dai, Aiguo; Fyfe, John C.; Xie, Shang-Ping; Dai, Xingang

    2015-06-01

    Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernible warming since about 2000, in sharp contrast to model simulations, which on average project strong warming. The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific, intensifying trade winds, changes in El Niño activity, increasing volcanic activity and decreasing solar irradiance. Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyse observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Interdecadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land. Combined with another leading mode of ICV, the IPO explains most of the difference between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called `hiatus' period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns different from those associated with GHG-induced warming or aerosol-induced cooling. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.

  16. Decadal Modulation of Global Surface Temperature By Internal Climate Variability

    NASA Astrophysics Data System (ADS)

    Dai, A.; Fyfe, J. C.; Xie, S. P.; Dai, X.

    2014-12-01

    Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernable warming since about 2000, in sharp contrast to model simulations which on average project strong warming. The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific, intensifying trade winds, changes in El Niño activity, increasing volcanic activity and decreasing solar irradiance. Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyze observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Inter-decadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land since 1920. Combined with another leading mode of ICV, the IPO explains most of the difference between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called "hiatus" period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns different from GHG-induced warming. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.

  17. Variable temperature system using vortex tube cooling and fiber optic temperature measurement for low temperature magic angle spinning NMR.

    PubMed

    Martin, Rachel W; Zilm, Kurt W

    2004-06-01

    We describe the construction and operation of a variable temperature (VT) system for a high field fast magic angle spinning (MAS) probe. The probe is used in NMR investigations of biological macromolecules, where stable setting and continuous measurement of the temperature over periods of several days are required in order to prevent sample overheating and degradation. The VT system described is used at and below room temperature. A vortex tube is used to provide cooling in the temperature range of -20 to 20 degrees C, while a liquid nitrogen-cooled heat exchanger is used below -20 degrees C. Using this arrangement, the lowest temperature that is practically achievable is -140 degrees C. Measurement of the air temperature near the spinning rotor is accomplished using a fiber optic thermometer that utilizes the temperature dependence of the absorption edge of GaAs. The absorption edge of GaAs also has a magnetic field dependence that we have measured and corrected for. This dependence was calibrated at several field strengths using the well-known temperature dependence of the (1)H chemical shift difference of the protons in methanol. PMID:15140428

  18. Florida Current Temperature and Salinity Variability during the Last Millennium

    NASA Astrophysics Data System (ADS)

    Lund, D. C.; Curry, W. B.

    2004-12-01

    Planktonic foraminiferal time series from four well-dated, high sedimentation rate cores exhibit significant changes in Florida Current δ 18O, SST, and δ 18Ow during the past 1000 years. On the Florida Margin (24.4 ° N, 83.3 ° W), G. ruber δ 18O in two cores increased by 0.1-0.2 ‰ from 500 to 200 yr BP. During the same time interval, Mg/Ca-derived SSTs warmed by 0.5-1.0 ° C. These shifts in δ 18O and temperature require an increase in δ 18Ow of 0.2-0.4 ‰ , equivalent to a salinity increase of 1-2 psu. From 200 yr BP to present, δ 18Ow values decreased by 0.1-0.2 ‰ . On the other side of the Florida Current (FC), two cores from the Great Bahama Bank (24.6 ° N, 79.3 ° W) also support a ~1-2 psu increase in salinity, but the shift occurs about 200 years later. G. ruber δ 18O at the Great Bahama Bank sites changed little from 1000 to 300 yr BP, but from 300 yr BP to present, it increased by 0.2-0.3 ‰ . SSTs during the last 300 years increased by 0.5-1.0 ° C, indicating that δ 18Ow increased by 0.3-0.4 ‰ since 300 yr BP. In the earlier portion of the record, δ 18Ow variability is on the order of 0.1 ‰ . Mg/Ca analyses from the Great Bahama Bank indicate that coretop SSTs are similar to those at 1000 yr BP (the so-called Medieval Warm Period). SSTs were 0.5-1.0 ° C cooler during the Little Ice Age (~750 to 200 yr BP). Although small, these changes in SST are consistent in magnitude and timing in two separate time series. The Florida Current SST variability is similar to that estimated for the Sargasso Sea (Keigwin, 1996), although the Sargasso Sea reconstruction implies higher SSTs than modern during the Medieval Warm Period. Changes in Florida Current salinity result from evaporation-precipitation variability in the central and western tropical Atlantic, the source region for much of the FC surface water (Schmitz and Richardson, 1991). Evidence of centennial-scale hydrologic variability from the Cariaco Basin (Haug et al., 2001; Black et al

  19. Correspondence of surface temperatures and terrain variables over a tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Friedl, Mark A.; Davis, Frank W.; Michaelsen, Joel C.

    1991-01-01

    The time-dependent correspondence between maps of surface brightness temperature derived from Landsat Thematic Mapper data and mapped terrain variables over a tallgrass prairie in northeastern Kansas is examined. Individual terrain variables including burning treatment, vegetation cover type (agriculture, prairie, woody vegetation), hillslope position, and greenness exhibit varying degrees of association with surface temperature. Burning treatment is most strongly associated with mid-morning surface temperature. Examination of terrain strata based on combinations of terrain variables, notably burning treatment and hillslope position, suggest that terrain variables interact in affecting surface temperature. Interaction between hillslope position, burning treatment, and surface temperature is more important in August than in May.

  20. Stratospheric temperature trends: impact of ozone variability and the QBO

    NASA Astrophysics Data System (ADS)

    Dall'Amico, Mauro; Gray, Lesley J.; Rosenlof, Karen H.; Scaife, Adam A.; Shine, Keith P.; Stott, Peter A.

    2010-02-01

    In most climate simulations used by the Intergovernmental Panel on Climate Change 2007 fourth assessment report, stratospheric processes are only poorly represented. For example, climatological or simple specifications of time-varying ozone concentrations are imposed and the quasi-biennial oscillation (QBO) of equatorial stratospheric zonal wind is absent. Here we investigate the impact of an improved stratospheric representation using two sets of perturbed simulations with the Hadley Centre coupled ocean atmosphere model HadGEM1 with natural and anthropogenic forcings for the 1979-2003 period. In the first set of simulations, the usual zonal mean ozone climatology with superimposed trends is replaced with a time series of observed zonal mean ozone distributions that includes interannual variability associated with the solar cycle, QBO and volcanic eruptions. In addition to this, the second set of perturbed simulations includes a scheme in which the stratospheric zonal wind in the tropics is relaxed to appropriate zonal mean values obtained from the ERA-40 re-analysis, thus forcing a QBO. Both of these changes are applied strictly to the stratosphere only. The improved ozone field results in an improved simulation of the stepwise temperature transitions observed in the lower stratosphere in the aftermath of the two major recent volcanic eruptions. The contribution of the solar cycle signal in the ozone field to this improved representation of the stepwise cooling is discussed. The improved ozone field and also the QBO result in an improved simulation of observed trends, both globally and at tropical latitudes. The Eulerian upwelling in the lower stratosphere in the equatorial region is enhanced by the improved ozone field and is affected by the QBO relaxation, yet neither induces a significant change in the upwelling trend.

  1. Temperature variable optimization for precision machine tool thermal error compensation on optimal threshold

    NASA Astrophysics Data System (ADS)

    Zhang, Ting; Ye, Wenhua; Liang, Ruijun; Lou, Peihuang; Yang, Xiaolan

    2013-01-01

    Machine tool thermal error is an important reason for poor machining accuracy. Thermal error compensation is a primary technology in accuracy control. To build thermal error model, temperature variables are needed to be divided into several groups on an appropriate threshold. Currently, group threshold value is mainly determined by researchers experience. Few studies focus on group threshold in temperature variable grouping. Since the threshold is important in error compensation, this paper arms to find out an optimal threshold to realize temperature variable optimization in thermal error modeling. Firstly, correlation coefficient is used to express membership grade of temperature variables, and the theory of fuzzy transitive closure is applied to obtain relational matrix of temperature variables. Concepts as compact degree and separable degree are introduced. Then evaluation model of temperature variable clustering is built. The optimal threshold and the best temperature variable clustering can be obtained by setting the maximum value of evaluation model as the objective. Finally, correlation coefficients between temperature variables and thermal error are calculated in order to find out optimum temperature variables for thermal error modeling. An experiment is conducted on a precise horizontal machining center. In experiment, three displacement sensors are used to measure spindle thermal error and twenty-nine temperature sensors are utilized to detect the machining center temperature. Experimental result shows that the new method of temperature variable optimization on optimal threshold successfully worked out a best threshold value interval and chose seven temperature variables from twenty-nine temperature measuring points. The model residual of z direction is within 3 μm. Obviously, the proposed new variable optimization method has simple computing process and good modeling accuracy, which is quite fit for thermal error compensation.

  2. PROCESSES INFLUENCING VARIABILITY IN CAVE DRIP WATER TEMPERATURES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have investigated five months of epikarst storage drip water temperatures along with surface air temperature and rainfall at a small waterfall in Cave Spring Caverns, Kentucky. Falling from about 4 m, water temperatures are measured within seconds of entering the cave passage with two minute, and...

  3. Core temperature: a forgotten variable in energy expenditure and obesity?

    PubMed

    Landsberg, L

    2012-12-01

    A substantial proportion of energy expenditure is utilized for maintenance of the 'warm-blooded' or homoeothermic state. In normally active humans, this compartment of energy output approximates 40% of total energy expenditure. Many mammalian species utilize regulated decreases in temperature, such as hibernation or shallow torpor, as a means of energy conservation. Inherited forms of rodent obesity (ob/ob mouse, fa/fa rat) have lower core temperatures and withstand cold poorly. Obese humans, however, have normal core temperatures. This review addresses the role of core temperature in the metabolic economy of the obese state and raises the possibility that (i) lower temperatures may contribute to the increase in metabolic efficiency that accompanies weight loss in the obese; and (ii) that lower core temperatures may have initiated weight gain in the pre-obese state and that the normal temperatures in the obese may represent metabolic compensation to restore energy balance and limit further weight gain. PMID:23107263

  4. SPATIAL VARIABILITY OF REMOTELY SENSED SURFACE TEMPERATURE AT FIELD SCALE

    EPA Science Inventory

    Bare soil surface temperatures (BST) and crop canopy temperatures (CCT) were collected from a 1-ha field in central Arizona using an infrared thermometer to determine whether they were spatially correlated. The measurements were taken from a two-dimensional random sampling patter...

  5. Seasonal variability in Arctic temperatures during early Eocene time

    NASA Astrophysics Data System (ADS)

    Eberle, Jaelyn J.; Fricke, Henry C.; Humphrey, John D.; Hackett, Logan; Newbrey, Michael G.; Hutchison, J. Howard

    2010-08-01

    As a deep time analog for today's rapidly warming Arctic region, early Eocene (52-53 Ma) rock on Ellesmere Island in Canada's High Arctic (˜ 79°N.) preserves evidence of lush swamp forests inhabited by turtles, alligators, primates, tapirs, and hippo-like Coryphodon. Although the rich flora and fauna of the early Eocene Arctic imply warmer, wetter conditions than at present, the quantification of Eocene Arctic climate has been more elusive. By analyzing oxygen isotope ratios of biogenic phosphate from mammal, fish, and turtle fossils from a single locality on central Ellesmere Island, we infer early Eocene Arctic temperatures, including mean annual temperature (MAT) of ˜ 8 °C, mean annual range in temperature of ˜ 16.5-19 °C, warm month mean temperature of 19-20 °C, and cold month mean temperature of 0-3.5 °C. Our seasonal range in temperature is similar to the range in estimated MAT obtained using different proxies. In particular, relatively high estimates of early Eocene Arctic MAT and SST by others that are based upon the distribution of branched glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in terrestrial soil bacteria and isoprenoid tetraether lipids in marine Crenarchaeota fall close to our warm month temperature, suggesting a bias towards summer values. From a paleontologic perspective, our temperature estimates verify that alligators and tortoises, by way of nearest living relative-based climatic inference, are viable paleoclimate proxies for mild, above-freezing year-round temperatures. Although for both of these reptilian groups, past temperature tolerances probably were greater than in living descendants.

  6. Seasonal variability in Arctic temperatures during the early Eocene

    NASA Astrophysics Data System (ADS)

    Eberle, J. J.; Fricke, H. C.; Humphrey, J.; Hackett, L.; Newbrey, M.; Hutchison, H.

    2009-12-01

    As a deep time analog for today’s rapidly warming Arctic region, early Eocene (~53 Ma) rocks on Ellesmere Island, Arctic Canada (~79° N.) preserve evidence of lush swamp forests inhabited by turtles, alligators, primates, tapirs, and hippo-like Coryphodon. Although the rich flora and fauna of the early Eocene Arctic imply warmer, wetter conditions that at present, quantitative estimates of Eocene Arctic climate are rare. By analyzing oxygen isotope ratios of biogenic phosphate from mammal, fish, and turtle fossils from a single locality on central Ellesmere Island, we provide estimates of early Eocene Arctic temperature, including mean annual temperature (MAT) of ~ 8° C, mean annual range in temperature (MART) of ~ 16.5° C, warm month mean temperature (WMMT) of 16 - 19° C, and cold month mean temperature (CMMT) of 0 - 1° C. Our seasonal range in temperature is similar to the range in estimated MAT obtained using different proxies. In particular, unusually high estimates of early Eocene Arctic MAT and sea surface temperature (SST) by others that are based upon the distribution of branched glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in terrestrial soil bacteria and marine Crenarchaeota fall within our range of WMMT, suggesting a bias towards summer values. Consequently, caution should be taken when using these methods to infer MAT and SST that, in turn, are used to constrain climate models. From a paleontologic perspective, our temperature estimates verify that alligators and tortoises, by way of nearest living relative-based climatic inference, are viable paleoclimate proxies for mild, above-freezing year-round temperatures. Although in both of these reptiles, past temperature tolerances were greater than in their living descendants.

  7. Thermodynamic Attributes of Spin, Temperature and Micro-Metallic Variables

    NASA Astrophysics Data System (ADS)

    Brooks, Jonathan

    1998-05-01

    Radial solutions to Schrodinger's equation change with temperature. Conjugate coordinates of these radial solutions satisfy the Euler-Lagrange equations and the Lorentz condition. Quantum mechanics does not bridge scale up. The exponential ratio of enthalpy to micro-entropy and Avogadro's number remedy this. The known properties at 298 Kelvin determine the Gueisen constant relating Cp and beta. Equilibrium at another temperature requires iterating an atomic radial shift to accommodate beta. A second iteration perturbss the shift until the mean target temperature of both Cp and beta is achieved. Required are 450 iterations from -100 to 1000 C that solve the radial solution some thirteen thousand times. Eccentricities of orbits are calculated. Spins range from .05 to .5 over the thirty transition elements, increasing with temperature.

  8. Variable Temperature Performance of a Si(Li) Detector Stack

    NASA Technical Reports Server (NTRS)

    Hubbard, G. Scott; McMurray, Robert E., Jr.; Keller, R. G.; Wercinski, P. F.; Walton, J. T.; Wong, Y. K.

    1994-01-01

    New experimental data is presented which displays 137Cs resolution of both single Si(Li) devices and a detector stack 2 cm in height as a function of temperature (85 K greater than or equal to T greater than or equal to 245 K). We also discuss variations in photopeak shape which indicate that detector charge collection may be temperature dependent over the range of interest.

  9. Western Arctic Ocean temperature variability during the last 8000 years

    USGS Publications Warehouse

    Farmer, Jesse R.; Cronin, Thomas M.; De Vernal, Anne; Dwyer, Gary S.; Keigwin, Loyd D.; Thunell, Robert C.

    2011-01-01

    We reconstructed subsurface (∼200–400 m) ocean temperature and sea-ice cover in the Canada Basin, western Arctic Ocean from foraminiferal δ18O, ostracode Mg/Ca ratios, and dinocyst assemblages from two sediment core records covering the last 8000 years. Results show mean temperature varied from −1 to 0.5°C and −0.5 to 1.5°C at 203 and 369 m water depths, respectively. Centennial-scale warm periods in subsurface temperature records correspond to reductions in summer sea-ice cover inferred from dinocyst assemblages around 6.5 ka, 3.5 ka, 1.8 ka and during the 15th century Common Era. These changes may reflect centennial changes in the temperature and/or strength of inflowing Atlantic Layer water originating in the eastern Arctic Ocean. By comparison, the 0.5 to 0.7°C warm temperature anomaly identified in oceanographic records from the Atlantic Layer of the Canada Basin exceeded reconstructed Atlantic Layer temperatures for the last 1200 years by about 0.5°C.

  10. Influence of circulation indices upon winter temperature variability in Egypt

    NASA Astrophysics Data System (ADS)

    Elmallah, E. S.; Elsharkawy, S. G.

    2011-03-01

    Trends of winter surface air temperature anomalies, WSATA, are investigated using data obtained from 13 monitoring stations. The analysis is performed in two steps; one deals with separate stations independently and the other deals with stations' groups. Groups' anomalies are correlated to circulation indices showing negative correlation between temperature with North Atlantic Oscillations and positive one with Mediterranean Oscillation Index. Both power analysis and frequency distribution analysis are applied. The results show existence of Schwabe, Hale and Gleissberg cycles and declare that there are no critical thermal changes of climate in Egypt. It is concluded that the temperature changes during the past three decades are not only because of the human activity but the extraterrestrial impacts as well.

  11. High temperature VSCF (Variable Speed Constant Frequency) generator system

    NASA Astrophysics Data System (ADS)

    Maphet, Thomas Allen; McCabria, Jack Lee; Kouba, Carroll Charles; Mitchell, James Thomas; Kwiecinski, James Robert

    1989-04-01

    The high temperature VSCF generator program was designed to develop a generating system capable of withstanding constantly high oil-in temperatures of 200 C in an ambient environment of 200 C. This is a requirement due to anticipated new fighter aircraft designs that will not be capable of cooling the oil to 100 C as in today's designs due to size restrictions of the heat exchanger and/or extended operation of the aircraft at supersonic speeds. The generator uses composite material to withstand the constant use of 200 C inlet oil.

  12. Temporal changes and variability in temperature series over Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Suhaila, Jamaludin

    2015-02-01

    With the current concern over climate change, the descriptions on how temperature series changed over time are very useful. Annual mean temperature has been analyzed for several stations over Peninsular Malaysia. Non-parametric statistical techniques such as Mann-Kendall test and Theil-Sen slope estimation are used primarily for assessing the significance and detection of trends, while a nonparametric Pettitt's test and sequential Mann-Kendall test are adopted to detect any abrupt climate change. Statistically significance increasing trends for annual mean temperature are detected for almost all studied stations with the magnitude of significant trend varied from 0.02°C to 0.05°C per year. The results shows that climate over Peninsular Malaysia is getting warmer than before. In addition, the results of the abrupt changes in temperature using Pettitt's and sequential Mann-Kendall test reveal the beginning of trends which can be related to El Nino episodes that occur in Malaysia. In general, the analysis results can help local stakeholders and water managers to understand the risks and vulnerabilities related to climate change in terms of mean events in the region.

  13. Models of Solar Irradiance Variability and the Instrumental Temperature Record

    NASA Technical Reports Server (NTRS)

    Marcus, S. L.; Ghil, M.; Ide, K.

    1998-01-01

    The effects of decade-to-century (Dec-Cen) variations in total solar irradiance (TSI) on global mean surface temperature Ts during the pre-Pinatubo instrumental era (1854-1991) are studied by using two different proxies for TSI and a simplified version of the IPCC climate model.

  14. Variable temperature NMR characterization of α-glycine

    NASA Astrophysics Data System (ADS)

    Taylor, R. E.; Dybowski, C.

    2008-10-01

    Proton NMR spin-lattice relaxation times in the laboratory frame ( T1) and in the rotating frame ( T1ρ) were measured as a function of temperature for a static sample of α-glycine. Both T1 and T1ρ data can be fit quantitatively by a single thermally-activated motion (the modulation of the dipolar coupling by random hopping about the threefold axis of the -NH 3 group), with no addition of other mechanisms at any temperature between 173 and 415 K. An activation energy of 21.7 ± 1 kJ/mol was extracted and is compared with previously reported values for both α- and γ-glycine. Such comparisons allow the correction of glycine polymorphs misidentified in the literature. The minimum in T1 at 325 K corresponds to a correlation time of 0.53 ns. Chemical shifts as a function of temperature were measured by 1H CRAMPS and by 13C and 15N CP/MAS experiments. These results are discussed relative to a previous report of anomalous electrical behavior in α-glycine within this temperature range.

  15. Lithology and temperature: How key mantle variables control rift volcanism

    NASA Astrophysics Data System (ADS)

    Shorttle, O.; Hoggard, M.; Matthews, S.; Maclennan, J.

    2015-12-01

    Continental rifting is often associated with extensive magmatic activity, emplacing millions of cubic kilometres of basalt and triggering environmental change. The lasting geological record of this volcanic catastrophism are the large igneous provinces found at the margins of many continents and abrupt extinctions in the fossil record, most strikingly that found at the Permo-Triassic boundary. Rather than being considered purely a passive plate tectonic phenomenon, these episodes are frequently explained by the involvement of mantle plumes, upwellings of mantle rock made buoyant by their high temperatures. However, there has been debate over the relative role of the mantle's temperature and composition in generating the large volumes of magma involved in rift and intra-plate volcanism, and even when the mantle is inferred to be hot, this has been variously attributed to mantle plumes or continental insulation effects. To help resolve these uncertainties we have combined geochemical, geophysical and modelling results in a two stage approach: Firstly, we have investigated how mantle composition and temperature contribute to melting beneath Iceland, the present day manifestation of the mantle plume implicated in the 54Ma break up of the North Atlantic. By considering both the igneous crustal production on Iceland and the chemistry of its basalts we have been able to place stringent constraints on the viable temperature and lithology of the Icelandic mantle. Although a >100°C excess temperature is required to generate Iceland's thick igneous crust, geochemistry also indicates that pyroxenite comprises 10% of its source. Therefore, the dynamics of rifting on Iceland are modulated both by thermal and compositional mantle anomalies. Secondly, we have performed a global assessment of the mantle's post break-up thermal history to determine the amplitude and longevity of continental insulation in driving excess volcanism. Using seismically constrained igneous crustal

  16. Development and Evaluation of a Variable-Temperature Quadrupole Ion Trap Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Derkits, David; Wiseman, Alex; Snead, Russell F.; Dows, Martina; Harge, Jasmine; Lamp, Jared A.; Gronert, Scott

    2016-02-01

    A new, variable-temperature mass spectrometer system is described. By applying polyimide heating tape to the end-cap electrodes of a Bruker (Bremen, Germany) Esquire ion trap, it is possible to vary the effective temperature of the system between 40 and 100°C. The modification does not impact the operation of the ion trap and the heater can be used for extended periods without degradation of the system. The accuracy of the ion trap temperatures was assessed by examining two gas-phase equilibrium processes with known thermochemistry. In each case, the variable-temperature ion trap provided data that were in good accord with literature data, indicating the effective temperature in the ion trap environment was being successfully modulated by the changes in the set-point temperatures on the end-cap electrodes. The new design offers a convenient and effective way to convert commercial ion trap mass spectrometers into variable-temperature instruments.

  17. Development and Evaluation of a Variable-Temperature Quadrupole Ion Trap Mass Spectrometer.

    PubMed

    Derkits, David; Wiseman, Alex; Snead, Russell F; Dows, Martina; Harge, Jasmine; Lamp, Jared A; Gronert, Scott

    2016-02-01

    A new, variable-temperature mass spectrometer system is described. By applying polyimide heating tape to the end-cap electrodes of a Bruker (Bremen, Germany) Esquire ion trap, it is possible to vary the effective temperature of the system between 40 and 100°C. The modification does not impact the operation of the ion trap and the heater can be used for extended periods without degradation of the system. The accuracy of the ion trap temperatures was assessed by examining two gas-phase equilibrium processes with known thermochemistry. In each case, the variable-temperature ion trap provided data that were in good accord with literature data, indicating the effective temperature in the ion trap environment was being successfully modulated by the changes in the set-point temperatures on the end-cap electrodes. The new design offers a convenient and effective way to convert commercial ion trap mass spectrometers into variable-temperature instruments. PMID:26483183

  18. Complexation of Plutonium (IV) with Fluoride at Variable Temperatures

    SciTech Connect

    Xia, Yuanxian; Rao, Linfeng; Friese, Judah I.; Moore, Dean A.; Bachelor, Paula P.

    2010-02-02

    The complexation of Pu(IV) with fluoride at elevated temperatures was studied by solvent extraction technique. A solution of NaBrO3 was used as holding oxidant to maintain the oxidation state of plutonium throughout the experiments. The distribution ratio of Pu(IV) between the organic and aqueous phases was found to decrease as the concentrations of fluoride were increased. Stability constants of the 1:1 and 1:2 Pu(IV)-F- complexes, dominant in the aqueous phase under the experimental conditions, were calculated from the effect of fluoride ions on the distribution ratio. The thermodynamic parameters, including enthalpy and entropy of complexation between Pu(IV) and fluoride at 25 degrees C - 55 degrees C were calculated from the stability constants at different temperatures by using the Van’t Hoff equation.

  19. A variable temperature ultrahigh vacuum atomic force microscope

    SciTech Connect

    Dai, Q.; Vollmer, R.; Carpick, R.W.; Ogletree, D.F.; Salmeron, M.

    1995-11-01

    A new atomic force microscope (AFM) that operates in ultrahigh vacuum (UHV) is described. The sample is held fixed with spring clamps while the AMF cantilever and deflection sensor are scanned above it. Thus, the sample is easily coupled to a liquid nitrogen cooled thermal reservoir which allows AFM operation from {approx}100 K to room temperature. AFM operation above room temperature is also possible. The microscope head is capable of coarse {ital x}-{ital y} positioning over millimeter distances so that AFM images can be taken virtually anywhere upon a macroscopic sample. The optical beam deflection scheme is used for detection, allowing simultaneous normal and lateral force measurements. The sample can be transferred from the AFM stage to a low energy electron diffraction/Auger electron spectrometer stage for surface analysis. Atomic lattice resolution AFM images taken in UHV are presented at 110, 296, and 430 K. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  20. Modelling Arctic Ozone Loss: Effects of Temperature on Interannual Variability

    NASA Astrophysics Data System (ADS)

    Podolske, J. R.; Drdla, K.

    2005-12-01

    Observations have shown that Arctic ozone loss is strongly correlated with the extent of cold temperatures over the course of the winter. In order to understand this relationship, a model has been used to simulate Arctic stratospheric evolution and ozone loss for each of the last 14 winters. The model includes detailed polar stratospheric cloud microphysics, allowing realistic calculations of denitrification, and comprehensive chemistry. Using the model, it is possible to quantify the relationships between specific factors (i.e., chlorine activation, denitrification, aerosol loading, and exposure to sunlight), ozone loss, and cold temperatures. An understanding of the mechanisms causing the observed ozone loss trends will allow more reliable estimates of the potential for future ozone loss.

  1. Variable temperature effects on release rates of readily soluble nuclides

    SciTech Connect

    Kim, C.-L.; Light, W.B.; Lee, W.W.-L.; Chambre, P.L.; Pigford, T.H.; Lawrence Berkeley Lab., CA )

    1988-09-01

    In this paper we study the effect of temperature on the release rate of readily soluble nuclides, as affected by a time-temperature dependent diffusion coefficient. In this analysis ground water fills the voids in the waste package at t = 0 and one percent of the inventories of cesium and iodine are immediately dissolved into the void water. Mass transfer resistance of partly failed container and cladding is conservatively neglected. The nuclides move through the void space into the surrounding rock under a concentration gradient. We use an analytic solution to compute the nuclide concentration in the gap or void, and the mass flux rate into the porous rock. 8 refs., 4 figs.

  2. Amplification and dampening of soil respiration by changes in temperature variability

    USGS Publications Warehouse

    Sierra, C.A.; Harmon, M.E.; Thomann, E.; Perakis, S.S.; Loescher, H.W.

    2011-01-01

    Accelerated release of carbon from soils is one of the most important feed backs related to anthropogenically induced climate change. Studies addressing the mechanisms for soil carbon release through organic matter decomposition have focused on the effect of changes in the average temperature, with little attention to changes in temperature vari-ability. Anthropogenic activities are likely to modify both the average state and the variability of the climatic system; therefore, the effects of future warming on decomposition should not only focus on trends in the average temperature, but also variability expressed as a change of the probability distribution of temperature.Using analytical and numerical analyses we tested common relationships between temperature and respiration and found that the variability of temperature plays an important role determining respiration rates of soil organic matter. Changes in temperature variability, without changes in the average temperature, can affect the amount of carbon released through respiration over the long term. Furthermore, simultaneous changes in the average and variance of temperature can either amplify or dampen there release of carbon through soil respiration as climate regimes change. The effects depend on the degree of convexity of the relationship between temperature and respiration and the magnitude of the change in temperature variance. A potential consequence of this effect of variability would be higher respiration in regions where both the mean and variance of temperature are expected to increase, such as in some low latitude regions; and lower amounts of respiration where the average temperature is expected to increase and the variance to decrease, such as in northern high latitudes.

  3. Note: A variable temperature cell for spectroscopy of thin films.

    PubMed

    Brock-Nannestad, T; Nielsen, C B; Bak, H Ø; Pittelkow, M

    2013-04-01

    We report the design and construction of a cell that enables precisely controlled measurement of UV∕Vis spectra of thin films on transparent substrates at temperatures up to 800 K. The dimensions of the setup are accommodated by a standard Varian Cary 5E spectrophotometer allowing for widespread use in standard laboratory settings. The cell also fits in a Bio-Rad IR-spectrometer. The cell is constructed with an outer water cooled heat shield of aluminum and an inner sample holder with heating element, thermo-resistor and windows, made from nickel coated copper. The cell can operate both in air, and with an inert gas filling. We illustrate the utility of the cell by characterization of three commercially available near infrared absorbers that are commonly used for laser welding of plastics and are known to possess high thermal stability. PMID:23635240

  4. Note: A variable temperature cell for spectroscopy of thin films

    NASA Astrophysics Data System (ADS)

    Brock-Nannestad, T.; Nielsen, C. B.; Bak, H. Ø.; Pittelkow, M.

    2013-04-01

    We report the design and construction of a cell that enables precisely controlled measurement of UV/Vis spectra of thin films on transparent substrates at temperatures up to 800 K. The dimensions of the setup are accommodated by a standard Varian Cary 5E spectrophotometer allowing for widespread use in standard laboratory settings. The cell also fits in a Bio-Rad IR-spectrometer. The cell is constructed with an outer water cooled heat shield of aluminum and an inner sample holder with heating element, thermo-resistor and windows, made from nickel coated copper. The cell can operate both in air, and with an inert gas filling. We illustrate the utility of the cell by characterization of three commercially available near infrared absorbers that are commonly used for laser welding of plastics and are known to possess high thermal stability.

  5. Phosphonium chloromercurate room temperature ionic liquids of variable composition.

    PubMed

    Metlen, Andreas; Mallick, Bert; Murphy, Richard W; Mudring, Anja-Verena; Rogers, Robin D

    2013-12-16

    The system trihexyl(tetradecyl)phosphonium ([P66614]Cl)/mercury chloride (HgCl2) has been investigated by varying the stoichiometric ratios from 4:1 to 1:2 (25, 50, 75, 100, 150, and 200 mol % HgCl2). All investigated compositions turn out to give rise to ionic liquids (ILs) at room temperature. The prepared ionic liquids offer the possibility to study the structurally and compositionally versatile chloromercurates in a liquid state at low temperatures in the absence of solvents. [P66614]2[HgCl4] is a simple IL with one discrete type of anion, while [P66614]{HgCl3} (with {} indicating a polynuclear arrangement) is an ionic liquid with a variety of polyanionic species, with [Hg2Cl6](2-) apparently being the predominant building block. [P66614]2[Hg3Cl8] and [P66614][Hg2Cl5] appear to be ILs at ambient conditions but lose HgCl2 when heated in a vacuum. For the liquids with the compositions 4:1 and 4:3, more than two discrete ions can be evidenced, namely, [P66614](+), [HgCl4](2-), and Cl(-) and [P66614](+), [HgCl4](2-), and the polynuclear {HgCl3}(-), respectively. The different stoichiometric compositions were characterized by (199)Hg NMR, Raman- and UV-vis spectroscopy, and cyclic voltammetry, among other techniques, and their densities and viscosities were determined. The [P66614]Cl/HgCl2 system shows similarities to the well-known chloroaluminate ILs (e.g., decrease in viscosity with increasing metal content after addition of more than 0.5 mol of HgCl2/mol [P66614]Cl, increasing density with increasing metal content, and the likely formation of polynuclear/polymeric/polyanionic species) but offer the advantage that they are air and water stable. PMID:24274831

  6. The absence of an Atlantic imprint on the multidecadal variability of wintertime European temperature

    PubMed Central

    Yamamoto, Ayako; Palter, Jaime B.

    2016-01-01

    Northern Hemisphere climate responds sensitively to multidecadal variability in North Atlantic sea surface temperature (SST). It is therefore surprising that an imprint of such variability is conspicuously absent in wintertime western European temperature, despite that Europe's climate is strongly influenced by its neighbouring ocean, where multidecadal variability in basin-average SST persists in all seasons. Here we trace the cause of this missing imprint to a dynamic anomaly of the atmospheric circulation that masks its thermodynamic response to SST anomalies. Specifically, differences in the pathways Lagrangian particles take to Europe during anomalous SST winters suppress the expected fluctuations in air–sea heat exchange accumulated along those trajectories. Because decadal variability in North Atlantic-average SST may be driven partly by the Atlantic Meridional Overturning Circulation (AMOC), the atmosphere's dynamical adjustment to this mode of variability may have important implications for the European wintertime temperature response to a projected twenty-first century AMOC decline. PMID:26975331

  7. The absence of an Atlantic imprint on the multidecadal variability of wintertime European temperature

    NASA Astrophysics Data System (ADS)

    Yamamoto, Ayako; Palter, Jaime B.

    2016-03-01

    Northern Hemisphere climate responds sensitively to multidecadal variability in North Atlantic sea surface temperature (SST). It is therefore surprising that an imprint of such variability is conspicuously absent in wintertime western European temperature, despite that Europe's climate is strongly influenced by its neighbouring ocean, where multidecadal variability in basin-average SST persists in all seasons. Here we trace the cause of this missing imprint to a dynamic anomaly of the atmospheric circulation that masks its thermodynamic response to SST anomalies. Specifically, differences in the pathways Lagrangian particles take to Europe during anomalous SST winters suppress the expected fluctuations in air-sea heat exchange accumulated along those trajectories. Because decadal variability in North Atlantic-average SST may be driven partly by the Atlantic Meridional Overturning Circulation (AMOC), the atmosphere's dynamical adjustment to this mode of variability may have important implications for the European wintertime temperature response to a projected twenty-first century AMOC decline.

  8. The absence of an Atlantic imprint on the multidecadal variability of wintertime European temperature.

    PubMed

    Yamamoto, Ayako; Palter, Jaime B

    2016-01-01

    Northern Hemisphere climate responds sensitively to multidecadal variability in North Atlantic sea surface temperature (SST). It is therefore surprising that an imprint of such variability is conspicuously absent in wintertime western European temperature, despite that Europe's climate is strongly influenced by its neighbouring ocean, where multidecadal variability in basin-average SST persists in all seasons. Here we trace the cause of this missing imprint to a dynamic anomaly of the atmospheric circulation that masks its thermodynamic response to SST anomalies. Specifically, differences in the pathways Lagrangian particles take to Europe during anomalous SST winters suppress the expected fluctuations in air-sea heat exchange accumulated along those trajectories. Because decadal variability in North Atlantic-average SST may be driven partly by the Atlantic Meridional Overturning Circulation (AMOC), the atmosphere's dynamical adjustment to this mode of variability may have important implications for the European wintertime temperature response to a projected twenty-first century AMOC decline. PMID:26975331

  9. Variability of sea surface temperature in the southwestern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    del Monte-Luna, Pablo; Villalobos, Héctor; Arreguín-Sánchez, Francisco

    2015-07-01

    The seasonal and interannual variability of sea surface temperature (SST) in the southwestern Gulf of Mexico (SGM) is related to changes in atmospheric forcing, subsurface water inputs, advection and surface currents. However, little is known about temperature variability in the gulf on decadal and multidecadal timescales. Temperature time series (1900-2010) were analysed in 36 2°×2° geographic quadrants that covered the SGM. A cluster analysis was applied to the data for the seasonal cycle and for the annual anomalies in each quadrant to describe SST variability, with a special focus on low frequencies (i.e. >10 years). Temperature anomalies were correlated with the identified cyclic components of the Atlantic Multidecadal Oscillation (AMO), and temperature variability in coastal quadrants of the gulf was described using multivariate analysis and harmonic analysys. There is a latitudinal separation of quadrants regading the seasonal cycle and a longitudinal separation in the total variability that is related to the Loop Current. The highest SST correlations were those related to a ~60-year cycle of the AMO and were found on the Yucatan shelf. The ~60-year variability is present in the entire gulf, but signals with periods shorter than ten years are more evident in the northern part. Extrapolation of the dominant sea surface temperature cycles in coastal areas of the gulf, shows that there will be a cooling event in the next 20 years.

  10. Evidence for large temperature fluctuations in quasar accretion disks from spectral variability

    SciTech Connect

    Ruan, John J.; Anderson, Scott F.; Agol, Eric; Dexter, Jason

    2014-03-10

    The well-known bluer-when-brighter trend observed in quasar variability is a signature of the complex processes in the accretion disk and can be a probe of the quasar variability mechanism. Using a sample of 604 variable quasars with repeat spectra in the Sloan Digital Sky Survey-I/II (SDSS), we construct difference spectra to investigate the physical causes of this bluer-when-brighter trend. The continuum of our composite difference spectrum is well fit by a power law, with a spectral index in excellent agreement with previous results. We measure the spectral variability relative to the underlying spectra of the quasars, which is independent of any extinction, and compare to model predictions. We show that our SDSS spectral variability results cannot be produced by global accretion rate fluctuations in a thin disk alone. However, we find that a simple model of an inhomogeneous disk with localized temperature fluctuations will produce power-law spectral variability over optical wavelengths. We show that the inhomogeneous disk will provide good fits to our observed spectral variability if the disk has large temperature fluctuations in many independently varying zones, in excellent agreement with independent constraints from quasar microlensing disk sizes, their strong UV spectral continuum, and single-band variability amplitudes. Our results provide an independent constraint on quasar variability models and add to the mounting evidence that quasar accretion disks have large localized temperature fluctuations.

  11. Evidence for Large Temperature Fluctuations in Quasar Accretion Disks from Spectral Variability

    NASA Astrophysics Data System (ADS)

    Ruan, John J.; Anderson, Scott F.; Dexter, Jason; Agol, Eric

    2014-03-01

    The well-known bluer-when-brighter trend observed in quasar variability is a signature of the complex processes in the accretion disk and can be a probe of the quasar variability mechanism. Using a sample of 604 variable quasars with repeat spectra in the Sloan Digital Sky Survey-I/II (SDSS), we construct difference spectra to investigate the physical causes of this bluer-when-brighter trend. The continuum of our composite difference spectrum is well fit by a power law, with a spectral index in excellent agreement with previous results. We measure the spectral variability relative to the underlying spectra of the quasars, which is independent of any extinction, and compare to model predictions. We show that our SDSS spectral variability results cannot be produced by global accretion rate fluctuations in a thin disk alone. However, we find that a simple model of an inhomogeneous disk with localized temperature fluctuations will produce power-law spectral variability over optical wavelengths. We show that the inhomogeneous disk will provide good fits to our observed spectral variability if the disk has large temperature fluctuations in many independently varying zones, in excellent agreement with independent constraints from quasar microlensing disk sizes, their strong UV spectral continuum, and single-band variability amplitudes. Our results provide an independent constraint on quasar variability models and add to the mounting evidence that quasar accretion disks have large localized temperature fluctuations.

  12. Reduced Surface Ocean Temperature Variability in the Eastern Equatorial Pacific During the Late Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Ford, H. L.; Ravelo, A. C.; Polissar, P. J.

    2012-12-01

    El Niño-Southern Oscillation is the largest source of global interannual variability with far-reaching climatic effects. Climate model simulations of future warming exhibit widely divergent behavior indicating an incomplete understanding of the factors that dictate tropical climate variability. Generating records of past tropical Pacific variability during times with different climate states is one approach to deepening our understanding of tropical climate change processes and improving predictions of future change. Here we reconstruct tropical Pacific ocean variability from the Last Glacial Maximum (LGM) and from the Holocene at ODP Sites 806 and 849, located in the western equatorial Pacific (WEP) warm pool and eastern equatorial Pacific (EEP) cold tongue, respectively. We reconstruct ocean temperature variability using the intra-sample distribution of Mg/Ca values from individual foraminifera. Sea surface temperature variability is reconstructed from individual specimens of G. sacculifer analyzed for Mg/Ca values with laser ablation ICP-MS (Photon Machines Analyte.193 with HelEx sample cell coupled with a Thermo ElementXS ICP-MS, LA-ICP-MS). Subsurface temperature variability is reconstructed from individual specimens of G. tumida analyzed for Mg/Ca values by ICP-OES. Our results indicate that the cooling of last glacial maximum SSTs was greater in the WEP compared to the EEP. Furthermore, we show this cooling is not an artifact of changes in seasonal or interannual foraminiferal fluxes, but rather, reflects overall cooler temperatures and thus changes in seasonal/interannual heat fluxes. At Site 806 in the WEP, variability during the Holocene and LGM was similar, suggesting the cooling was a direct response to pCO2-radiative forcing. In contrast, at Site 849, sea surface temperature variability during the LGM was greatly diminished in comparison to the Holocene suggesting reduced ENSO and seasonal variability. Therefore conditions in the EEP responded to both

  13. Influence of Climate on Emergency Department Visits for Syncope: Role of Air Temperature Variability

    PubMed Central

    Galli, Andrea; Barbic, Franca; Borella, Marta; Costantino, Giorgio; Perego, Francesca; Dipaola, Franca; Casella, Francesco; Duca, Pier Giorgio; Diedrich, Andrè; Raj, Satish; Robertson, David; Porta, Alberto; Furlan, Raffaello

    2011-01-01

    Background Syncope is a clinical event characterized by a transient loss of consciousness, estimated to affect 6.2/1000 person-years, resulting in remarkable health care and social costs. Human pathophysiology suggests that heat may promote syncope during standing. We tested the hypothesis that the increase of air temperatures from January to July would be accompanied by an increased rate of syncope resulting in a higher frequency of Emergency Department (ED) visits. We also evaluated the role of maximal temperature variability in affecting ED visits for syncope. Methodology/Principal Findings We included 770 of 2775 consecutive subjects who were seen for syncope at four EDs between January and July 2004. This period was subdivided into three epochs of similar length: 23 January–31 March, 1 April–31 May and 1 June–31 July. Spectral techniques were used to analyze oscillatory components of day by day maximal temperature and syncope variability and assess their linear relationship. There was no correlation between daily maximum temperatures and number of syncope. ED visits for syncope were lower in June and July when maximal temperature variability declined although the maximal temperatures themselves were higher. Frequency analysis of day by day maximal temperature variability showed a major non-random fluctuation characterized by a ∼23-day period and two minor oscillations with ∼3- and ∼7-day periods. This latter oscillation was correlated with a similar ∼7-day fluctuation in ED visits for syncope. Conclusions/Significance We conclude that ED visits for syncope were not predicted by daily maximal temperature but were associated with increased temperature variability. A ∼7-day rhythm characterized both maximal temperatures and ED visits for syncope variability suggesting that climate changes may have a significant effect on the mode of syncope occurrence. PMID:21818372

  14. A novel method to analyze NO2 spatiotemporal variability over Eastern China

    NASA Astrophysics Data System (ADS)

    Liu, Mengyao; Lin, Jintai; Wang, Yuchen; Sun, Yang; Zheng, Bo; Shao, Jinyuan; Cheng, Jinxuan; Yan, Yingying; Zheng, Yixuan

    2016-04-01

    Over Eastern China (consisted of North China and East China), nitrogen dioxide (NO2), particulate matters with diameter less than 2.5 μm (PM2.5) and other air pollutants vary significantly in space and undergo diurnal and day-to-day variations. In particular, the day-to-day variability of pollutants is weather-determined and largely non-periodic and non-stationary, posing a difficulty for a conventional time series analysis using Fourier or wavelet decomposition. Here, we use an EOF-EEMD decomposition method to evaluate the spatiotemporal variability of ground-level NO2, PM2.5, and their associations with meteorological processes. The EOF-EEMD method consists of an EOF analysis to separate temporal and spatial components and a subsequent EEMD decomposition step to separate temporal scales of either stationary or non-stationary nature. The NO2 and PM2.5 data are taken from about 160 air quality automatic monitoring stations over 25th October to 25th December and correspondent meteorology observations are taken from about 90 stations. The observed concentrations of NO2 and PM2.5 as well as some meteorological factors such as temperature at 2 meters, relative moisture (RH) and wind speed exhibit large day-to-day variability, in time intervals consistent with the passage of cold fronts. Depending on the strength of the passing cold fonts, pollutants can be cleaned up over the whole Eastern China or over the northern parts of the region only. This leads to a clear difference in pollution day-to-day variability between North China and East China. We further apply the EOF-EEMD analysis to evaluate the simulations of GEOS-Chem and CMAQ chemical transport models in capturing the observed spatiotemporal variations of pollutants. We find that both models capture the spatial variation of the observed NO2 fairly well, but they are not able to reproduce the day-to-day variation of NO2. Detailed model and observation analyses are still ongoing.

  15. Hydrogeologic controls on baseflow temperature distributions: Implications for stream temperature response to climate variability

    NASA Astrophysics Data System (ADS)

    Boutt, D. F.; Smith, Z.

    2012-12-01

    Ground water temperature distributions in the near surface are not uniform and are the complex result of a variety of near- and sub-surface processes. Heat from the atmosphere is input into the ground via conduction at the ground surface and advection of infiltrating water. These processes produce predictable distributions of temperature that have been used to investigate current and past climatic conditions, determine ground water velocities, and assess basin-scale heat transport in sedimentary systems. The purpose of this investigation is to test a hypothesis that timing and nature of ground water recharge (advection of heat into the subsurface) is a significant control on the temporal and spatial distribution of heat in the shallow subsurface. The advective movement of heat imposes a dominant control on the 3-dimensional subsurface temperature distribution and strongly affects stream baseflow temperatures. We present observational data supporting a strong hydrogeologic control on subsurface water temperatures. These temperature distributions are modified by advection and are significantly different than theoretical distributions in a conduction-dominated environment. The temperature distributions with depth and space are controlled by the aquifers internal hydrogeologic structure and connections to recharge areas. Synthetic modeling is used to address the following questions: (1) how quickly do ground water temperatures respond to a changing climate, and how quickly do they reach a new equilibrium following perturbation; (2) what is the role of recharge water temperature and timing on subsurface temperature distributions; and (3) how do these factors influence baseflow temperatures in stream systems of varying size. Two-dimensional numerical models are developed using Comsol Multiphysics to perform a sensitivity analysis of basin-scale temperature response and coupling to surface water. In nested ground water flow systems, discharge areas farther down the

  16. Kiloampere, Variable-Temperature, Critical-Current Measurements of High-Field Superconductors

    PubMed Central

    Goodrich, LF; Cheggour, N; Stauffer, TC; Filla, BJ; Lu, XF

    2013-01-01

    We review variable-temperature, transport critical-current (Ic) measurements made on commercial superconductors over a range of critical currents from less than 0.1 A to about 1 kA. We have developed and used a number of systems to make these measurements over the last 15 years. Two exemplary variable-temperature systems with coil sample geometries will be described: a probe that is only variable-temperature and a probe that is variable-temperature and variable-strain. The most significant challenge for these measurements is temperature stability, since large amounts of heat can be generated by the flow of high current through the resistive sample fixture. Therefore, a significant portion of this review is focused on the reduction of temperature errors to less than ±0.05 K in such measurements. A key feature of our system is a pre-regulator that converts a flow of liquid helium to gas and heats the gas to a temperature close to the target sample temperature. The pre-regulator is not in close proximity to the sample and it is controlled independently of the sample temperature. This allows us to independently control the total cooling power, and thereby fine tune the sample cooling power at any sample temperature. The same general temperature-control philosophy is used in all of our variable-temperature systems, but the addition of another variable, such as strain, forces compromises in design and results in some differences in operation and protocol. These aspects are analyzed to assess the extent to which the protocols for our systems might be generalized to other systems at other laboratories. Our approach to variable-temperature measurements is also placed in the general context of measurement-system design, and the perceived advantages and disadvantages of design choices are presented. To verify the accuracy of the variable-temperature measurements, we compared critical-current values obtained on a specimen immersed in liquid helium (“liquid” or Ic liq) at

  17. Monitoring variability in trends of temperature and rainfall in the Apennine Alps (Middle Italy)

    NASA Astrophysics Data System (ADS)

    D'Aprile, Fabrizio; Tapper, Nigel

    2016-04-01

    In 2006 the School of Geography and Environmental Sciences of Monash University in collaboration with the Italian Forest Corps (Corpo Forestale dello Stato), Uffici Territoriali per la Biodiversità di Vallombrosa (Florence) and Pratovecchio (Arezzo)started to monitor the variability in temperature and rainfall in the Tuscan Apennine Alps (Middle Italy). First results showed unexpected variability in trends of both the climate variables and in particular very high variability in similarity of trends among sites even at short distance. Although the time series are ultra-centenary in some sites, trends in temperature and rainfall at the monthly level would show a reduction in temperature and increase in rainfall in the last decade in some cases. This uncertainty poses the question whether the phenomenon was due to some anomaly in the periodical oscillations of 6-7 years of length (spectral Fourier analysis) or the dominant trends in variability of monthly temperature and monthly rainfall are unchanged. Recent analysis of trends would confirm warming and drying of climate in the Apennine Alps in Middle Italy; however, in some sites a relative cooling is shown in the 2000s. In the area, climate warming appears to reach levels that may have relevant implications for forest composition and shift. The relatively fast increase in temperature and reduction in rainfall during the last 3-4 decades further strengthens the importance to continue monitoring climate variability to a deeper level and extend the understanding of its effects at the local level.

  18. Spatial patterns of historical temperature variability: Global correlations using spectral and wavelet techniques

    SciTech Connect

    Park, J.

    1995-12-31

    In order to assess man`s impact on global climate, we need to understand natural climate variability more fully. Using 100 years of global temperature data, we have developed time-series methods that identify coherent spatio-temporal {open_quotes}modes{close_quotes} of temperature variability e.g., El Nino-Southern Oscillation (ENSO) cycles. Methods based on multiple-taper spectral analysis estimate the correlated temperature variability within narrow frequency bands. Methods based on a multiple wavelet analysis identify short-term global temperature {open_quotes}events{close_quotes} on a range of time scales. We assess the statistical significance of narrow-band and event correlations from Monte Carlo confidence limits, which are derived from stochastic variations of uncorrelated white-noise time series. Significant patterns of variability with 2.8 to 5.7 year duration exhibit the characteristic ENSO pattern: warming in the tropics, followed by temperature excursions in middle latitudes. An interdecadal mode (15-18 years) appears to represent long-term ENSO variability, an interpretation supported by the persistence of warm Pacific Ocean surface water in the decade after the large 1982-3 El Nino episode. The interdecadal mode appears to explain much of the anomalous global warmth of the 1980s. North Atlantic variability dominates quasi-biennial (2.2 years) and decadal (7-12 years) modes.

  19. Impacts of temperature and its variability on mortality in New England

    NASA Astrophysics Data System (ADS)

    Shi, Liuhua; Kloog, Itai; Zanobetti, Antonella; Liu, Pengfei; Schwartz, Joel D.

    2015-11-01

    Rapid build-up of greenhouse gases is expected to increase Earth’s mean surface temperature, with unclear effects on temperature variability. This makes understanding the direct effects of a changing climate on human health more urgent. However, the effects of prolonged exposures to variable temperatures, which are important for understanding the public health burden, are unclear. Here we demonstrate that long-term survival was significantly associated with both seasonal mean values and standard deviations of temperature among the Medicare population (aged 65+) in New England, and break that down into long-term contrasts between ZIP codes and annual anomalies. A rise in summer mean temperature of 1 °C was associated with a 1.0% higher death rate, whereas an increase in winter mean temperature corresponded to a 0.6% decrease in mortality. Increases in standard deviations of temperature for both summer and winter were harmful. The increased mortality in warmer summers was entirely due to anomalies, whereas it was long-term average differences in the standard deviation of summer temperatures across ZIP codes that drove the increased risk. For future climate scenarios, seasonal mean temperatures may in part account for the public health burden, but the excess public health risk of climate change may also stem from changes of within-season temperature variability.

  20. Isoconversion effective activation energy profiles by variable temperature diffuse reflection infrared spectroscopy.

    PubMed

    White, Daniel R; White, Robert L

    2008-01-01

    Thermal process characterization based on calculating effective activation energies from variable temperature diffuse reflection infrared spectroscopy (VT-DRIFTS) measurements is demonstrated. Experimental factors that affect the accuracies of activation energy values are outlined. Infrared radiation scattering efficiency, thermal conductivity, and inertness towards chemical reactions are factors that should be considered when selecting an appropriate diluent for preparing samples. The Kubelka-Munk representation is superior to apparent absorbance when baseline variations in spectra measured at different temperatures can be minimized. Variable-temperature infrared spectral features, such as integrated absorption band area, can be used to compute isoconversion effective activation energies, provided that measured quantities are proportional to species concentrations. PMID:18230216

  1. Effect of variability in weather conditions on conductor temperature and the dynamic rating of transmission lines

    SciTech Connect

    Foss, S.D.; Lin, S.H. ); Maraio, R.A.; Schrayshuen, H. )

    1988-10-01

    Simultaneous weather and conductor data were collected from these locations situated in New York State and Western Massachusetts. The two New York State locations represent the termination points of a 230 kV seventy-mile overhead line. The transmission line consists of a Drake 795 kcmil ACSR conductor. Data were monitored using on-line sensor equipment developed by the Research and Development Department of the Niagara Mohawk Power Corporation. The purposes of the investigation were to analyze variability in weather conditions, conductor temperature and calculated dynamic ratings that exist along transmission lines. Reported here are variabilities in air temperature, wind speed, conductor current, conductor surface temperature and calculated dynamic ratings.

  2. Trends in intra- and inter-annual temperature variabilities across Sudan.

    PubMed

    Elagib, Nadir Ahmed

    2010-01-01

    Four mean temperature variables, namely maximum (MAX), minimum (MIN), mean (MEAN) and diurnal temperature range (DTR), were considered for 14 selected observational stations throughout Sudan. The objectives were to investigate the seasonal and annual regimes, the seasonal and annual trends, the intra-annual variability (IAV) by the coefficient of variation (CV), and the interrelationships between the temperature variables and percent of possible sunshine. A mounting evidence of daytime and nighttime warming since the 1940s until 2005 is presented. The exception is the dry season which is dominated by daytime cooling attributable to the damping effect of dust haze/storms. Apparently, the progressive drought across inland locations has raised the MAXs, and to a lesser extent the MINs, of the wet season over those for the hot season. Accordingly, maximum rates of 0.451 and 0.336 degrees C decade(-1) were found for the nighttime and daytime temperatures, respectively. The extreme eastern and western locations have been frequently dominated by the warmest trend rates obtained nationwide. The prevalence of significant decreases (increases) of DTR is more apparent in the dry, hot and annual series (wet series). Depending on the temperature variable under consideration, many stations possessed significant trends toward either increased or decreased variability of the within-year monthly values, i.e. IAV. The correlation between the time series of annual CV and extreme values for each of the four temperature variables shows generally that warmer climate in Sudan is associated with higher intra-annual temperature variability and vise versa, i.e. the CV is directly correlated with the highest value within the year, but inversely correlated with the lowest one. The findings of this investigation also indicate that the DTR is directly related to percent of possible sunshine, but the relationship of the latter parameter is not so clear with MAX, MIN and MEAN. PMID:21053725

  3. Complexation of Lanthanides with Nitrate at Variable Temperatures: Thermodynamics and Coordination Modes

    SciTech Connect

    Rao, Linfeng; Tian, Guoxin

    2008-12-10

    Complexation of neodymium(III) with nitrate was studied at variable temperatures (25, 40, 55 and 70 C) by spectrophotometry and microcalorimetry. The NdNO{sub 3}{sup 2+} complex is weak and becomes slightly stronger as the temperature is increased. The enthalpy of complexation at 25 C was determined by microcalorimetry to be small and positive, (1.5 {+-} 0.2) kJ {center_dot} mol{sup -1}, in good agreement with the trend of the stability constant at variable temperatures. Luminescence emission spectra and lifetime of Eu(III) in nitrate solutions suggest that inner-sphere and bidentate complexes form between trivalent lanthanides (Nd{sup 3+} and Eu{sup 3+}) and nitrate in aqueous solutions. Specific Ion Interaction approach (SIT) was used to obtain the stability constants of NdNO{sub 3}{sup 2+} at infinite dilution and variable temperatures.

  4. A variable-temperature nanostencil compatible with a low-temperature scanning tunneling microscope/atomic force microscope

    SciTech Connect

    Steurer, Wolfram Gross, Leo; Schlittler, Reto R.; Meyer, Gerhard

    2014-02-15

    We describe a nanostencil lithography tool capable of operating at variable temperatures down to 30 K. The setup is compatible with a combined low-temperature scanning tunneling microscope/atomic force microscope located within the same ultra-high-vacuum apparatus. The lateral movement capability of the mask allows the patterning of complex structures. To demonstrate operational functionality of the tool and estimate temperature drift and blurring, we fabricated LiF and NaCl nanostructures on Cu(111) at 77 K.

  5. Daily and Interannual Variability of Air Temperature and Precipitation As Agricultural Factor

    NASA Astrophysics Data System (ADS)

    Sourkova, G.; Pona, C.

    The problem investigated concerns wheat growing process sensitivity to the changes in climate variability. For the sensitivity analysis five CERES-model runs are held for three stations in Italy: Decimomannu (Sardinia), Brindisi (Apulia) and Ghedi (Padana valley, Veneto). The only difference between these five experiments for each station is a weather input. All five weather inputs for each location are simulated by weather generator WXGEN. First run ("base") is forced by weather input having tempera- ture and precipitation variance equal to the present-day values (1960-1990). Then two crop simulations are made with changed "base" interannual variance of monthly to- tal precipitation by multiplicative factors 0.5 and 2. Temperature variability remains unchanged. Last two model runs are carried out with daily halved and doubled temper- ature variance, precipitation variability is the same as in "base" simulation. Investiga- tion showed that doubled precipitation variability is accompanied at all three locations by the largest amounts of yield variability for all five scenarios. Decreased precipi- tation variability is followed by yield decline and, at the same time the amplitude of yield change is the least compared with other forcings. Decreasing of precipitation variability results in noticeably raised harvest index for the years of minimum yield. For Decimomannu and Brindisi it is almost equal to that of the maximum yield years. In general, more significantly expressed response of the yield amounts occurs for pre- cipitation variability forcings. The influence of temperature variability changes seems to be less for all three locations.

  6. Temperature variability and moisture synergistically interact to exacerbate an epizootic disease.

    PubMed

    Raffel, Thomas R; Halstead, Neal T; McMahon, Taegan A; Davis, Andrew K; Rohr, Jason R

    2015-02-22

    Climate change is altering global patterns of precipitation and temperature variability, with implications for parasitic diseases of humans and wildlife. A recent study confirmed predictions that increased temperature variability could exacerbate disease, because of lags in host acclimation following temperature shifts. However, the generality of these host acclimation effects and the potential for them to interact with other factors have yet to be tested. Here, we report similar effects of host thermal acclimation (constant versus shifted temperatures) on chytridiomycosis in red-spotted newts (Notophthalmus viridescens). Batrachochytrium dendrobatidis (Bd) growth on newts was greater following a shift to a new temperature, relative to newts already acclimated to this temperature (15°C versus 25°C). However, these acclimation effects depended on soil moisture (10, 16 and 21% water) and were only observed at the highest moisture level, which induced greatly increased Bd growth and infection-induced mortality. Acclimation effects were also greater following a decrease rather than an increase in temperature. The results are consistent with previous findings that chytridiomycosis is associated with precipitation, lower temperatures and increased temperature variability. This study highlights host acclimation as a potentially general mediator of climate-disease interactions, and the need to account for context-dependencies when testing for acclimation effects on disease. PMID:25567647

  7. Functional diversity of catch mitigates negative effects of temperature variability on fisheries yields.

    PubMed

    Dee, Laura E; Miller, Steve J; Peavey, Lindsey E; Bradley, Darcy; Gentry, Rebecca R; Startz, Richard; Gaines, Steven D; Lester, Sarah E

    2016-08-17

    Temperature variation within a year can impact biological processes driving population abundances. The implications for the ecosystem services these populations provide, including food production from marine fisheries, are poorly understood. Whether and how temperature variability impacts fishery yields may depend on the number of harvested species and differences in their responses to varying temperatures. Drawing from previous theoretical and empirical studies, we predict that greater temperature variability within years will reduce yields, but harvesting a larger number of species, especially a more functionally diverse set, will decrease this impact. Using a global marine fisheries dataset, we find that within-year temperature variability reduces yields, but current levels of functional diversity (FD) of targeted species, measured using traits related to species' responses to temperature, largely offset this effect. Globally, high FD of catch could avoid annual losses in yield of 6.8% relative to projections if FD were degraded to the lowest level observed in the data. By contrast, species richness in the catch and in the ecosystem did not provide a similar mitigating effect. This work provides novel empirical evidence that short-term temperature variability can negatively impact the provisioning of ecosystem services, but that FD can buffer these negative impacts. PMID:27534960

  8. Spatial and temporal variability of temperature and precipitation over Iraq and its relation with global sea surface temperature

    NASA Astrophysics Data System (ADS)

    Alkhalidi, Jasim; Stefan, Sabina; Dima, Mihai

    2016-04-01

    In this study we have examined the spatial and temporal variability of mean temperature (0C) and precipitation (mm) in winter (DJF) and spring (MAM) in Iraq. The data used were recorded at 12 stations for temperature and 18stations for precipitation over the period 1981-2010. An empirical orthogonal function (EOFs) and principal component (PCs) analysis were employed to characterize the spatial variability of the climatological parameters. The first EOF of temperature has the most variance (80%) and it is monopolar. This means it is related with large scale patterns. The first EOF of precipitation has variance (70%) lower than that of EOF1 for temperature, because the precipitation is a local phenomenon. The analysis of PCS for temperature showed different trends for the different time intervals. In addition, the relation between the global sea surface temperature (SST) and the temperature and precipitation PCs was analyzed. The results derived through correlations maps indicate links between Iraq climate and El Nino southern oscillation (ENSO) and Atlantic multidecadal oscillation (AMO), large scale patterns.

  9. Ocean surface temperature variability: Large model–data differences at decadal and longer periods

    PubMed Central

    Laepple, Thomas; Huybers, Peter

    2014-01-01

    The variability of sea surface temperatures (SSTs) at multidecadal and longer timescales is poorly constrained, primarily because instrumental records are short and proxy records are noisy. Through applying a new noise filtering technique to a global network of late Holocene SST proxies, we estimate SST variability between annual and millennial timescales. Filtered estimates of SST variability obtained from coral, foraminifer, and alkenone records are shown to be consistent with one another and with instrumental records in the frequency bands at which they overlap. General circulation models, however, simulate SST variability that is systematically smaller than instrumental and proxy-based estimates. Discrepancies in variability are largest at low latitudes and increase with timescale, reaching two orders of magnitude for tropical variability at millennial timescales. This result implies major deficiencies in observational estimates or model simulations, or both, and has implications for the attribution of past variations and prediction of future change. PMID:25385623

  10. Recent Climate Variability in Antarctica from Satellite-derived Temperature Data

    NASA Technical Reports Server (NTRS)

    Schneider, David P.; Steig, Eric J.; Comiso, Josefino C.

    2004-01-01

    Recent Antarctic climate variability on month-to-month to interannual time scales is assessed through joint analysis of surface temperatures from satellite thermal infrared observations (T(sub IR)) and passive microwave brightness temperatures (T(sub B)). Although Tw data are limited to clear-sky conditions and T(sub B) data are a product of the temperature and emissivity of the upper approx. 1m of snow, the two data sets share significant covariance. This covariance is largely explained by three empirical modes, which illustrate the spatial and temporal variability of Antarctic surface temperatures. T(sub B) variations are damped compared to TIR variations, as determined by the period of the temperature forcing and the microwave emission depth; however, microwave emissivity does not vary significantly in time. Comparison of the temperature modes with Southern Hemisphere (SH) 500-hPa geopotential height anomalies demonstrates that Antarctic temperature anomalies are predominantly controlled by the principal patterns of SH atmospheric circulation. The leading surface temperature mode strongly correlates with the Southern Annular Mode (SAM) in geopotential height. The second temperature mode reflects the combined influences of the zonal wavenumber-3 and Pacific South American (PSA) patterns in 500-hPa height on month-to-month timescales. ENSO variability projects onto this mode on interannual timescales, but is not by itself a good predictor of Antarctic temperature anomalies. The third temperature mode explains winter warming trends, which may be caused by blocking events, over a large region of the East Antarctic plateau. These results help to place recent climate changes in the context of Antarctica's background climate variability and will aid in the interpretation of ice core paleoclimate records.

  11. Variability patterns of the general circulation and sea water temperature in the North Sea

    NASA Astrophysics Data System (ADS)

    Mathis, M.; Elizalde, A.; Mikolajewicz, U.; Pohlmann, T.

    2015-06-01

    This study investigates patterns of spatio-temporal variability in the North Sea and their major driving mechanisms. Leading variability modes of the general circulation and sea water temperature are extracted from model results by means of Empirical Orthogonal Functions (EOF) analysis. The model results originate from an uncoupled simulation with the global ocean model MPIOM, forced with ERA40 reanalysis data at the air-sea interface. For this regional model study, MPIOM has been run with a stretched grid configuration enabling higher horizontal resolution in the Northwest European Shelf and North Atlantic ocean. The analysis is applied to interannual variabilities of winter and summer separately. The results indicate that on seasonal scales the leading variability mode of the general circulation affects the entire North Sea, accompanied by significant inflow anomalies through the Fair-Isle Passage. Correlations of the corresponding Principal Component (PC) with wind density functions reveal the circulation anomalies to coincide with westerly and south-westerly wind anomalies. The second mode describes circulation anomalies along the Norwegian Trench and English Channel, which correlate with north-westerly wind anomalies caused by variations in large-scale atmospheric pressure areas centered over the British Isles. For sea water temperature, distinct variability patterns are induced by variable surface heat fluxes, vertical mixing, and variable advective heat fluxes. The first mode of both the general circulation and water temperature in winter mainly represents the response to atmospheric variations in the North Atlantic Oscillation (NAO). However, the higher modes account for such variabilities that cannot be explained by the NAO. As a consequence of the integrated effects of the different variability modes on the circulation system and heat content, local correlations of the NAO with volume transports and water temperature are weakened in the regions of

  12. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  13. Temperature Variability Associated with the Middle Atmosphere Electrodynamics (MAE-1) Campaign

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.

    1999-01-01

    Meteorological rockets launched during the Middle Atmosphere Electrodynamics (MAE-1) Campaign in October 1980 from Andoya Rocket Range (ARR), Norway, exhibited large and unexpected temperature variability. Temperatures were found to vary as much as 20 C within a few hours and demonstrated a similar type of variability from one day to the next. Following examination of the reduced rocketsonde profiles the question was raised whether the observed variability was due to natural atmospheric variability or instrument malfunction. Small-scale variability, as observed, may result from one or multiple sources, e.g., intense storms upstream from the observing site, orography such as mountain waves off of the Greenland Plateau, convective activity, gravity waves, etc. Arranging the observations spaced over time showed that the perturbations moved downward. Prior to MAE-1 very few small rocketsonde measurements had been launched from ARR, thus the quality of the initial measurements in early October caused concern when the large variability was noted. We discuss the errors of the rocketsonde measurements, graphically review the nature of the variability observed, compare the data with other measurements, and postulate a possible cause for the variability.

  14. Effects of outdoor temperature on changes in physiological variables before and after lunch in healthy women

    NASA Astrophysics Data System (ADS)

    Okada, Masahiro; Kakehashi, Masayuki

    2014-03-01

    Previous studies of autonomic nervous system responses before and after eating when controlling patient conditions and room temperature have provided inconsistent results. We hypothesized that several physiological parameters reflecting autonomic activity are affected by outdoor temperature before and after a meal. We measured the following physiological variables before and after a fixed meal in 53 healthy Japanese women: skin temperature, systolic and diastolic blood pressure, salivary amylase, blood glucose, heart rate, and heart rate variability. We assessed satiety before and after lunch using a visual analog scale (100 mm). We recorded outdoor temperature, atmospheric pressure, and relative humidity. Skin temperature rose significantly 1 h after eating (greater in cold weather) (P = 0.008). Cold weather markedly influenced changes in diastolic blood pressure before (P = 0.017) and after lunch (P = 0.013). Fasting salivary amylase activity increased significantly in cold weather but fell significantly after lunch (significantly greater in cold weather) (P = 0.007). Salivary amylase was significantly associated with cold weather, low atmospheric pressure, and low relative humidity 30 min after lunch (P < 0.05). Cold weather significantly influenced heart rate variability (P = 0.001). The decreased low frequency (LF)/high frequency (HF) ratio, increased Δ LF/HF ratio, and increased Δ salivary amylase activity imply that cold outdoor temperature is associated with dominant parasympathetic activity after lunch. Our results clarify the relationship between environmental factors, food intake, and autonomic system and physiological variables, which helps our understanding of homeostasis and metabolism.

  15. A temperature rise reduces trial-to-trial variability of locust auditory neuron responses.

    PubMed

    Eberhard, Monika J B; Schleimer, Jan-Hendrik; Schreiber, Susanne; Ronacher, Bernhard

    2015-09-01

    The neurophysiology of ectothermic animals, such as insects, is affected by environmental temperature, as their body temperature fluctuates with ambient conditions. Changes in temperature alter properties of neurons and, consequently, have an impact on the processing of information. Nevertheless, nervous system function is often maintained over a broad temperature range, exhibiting a surprising robustness to variations in temperature. A special problem arises for acoustically communicating insects, as in these animals mate recognition and mate localization typically rely on the decoding of fast amplitude modulations in calling and courtship songs. In the auditory periphery, however, temporal resolution is constrained by intrinsic neuronal noise. Such noise predominantly arises from the stochasticity of ion channel gating and potentially impairs the processing of sensory signals. On the basis of intracellular recordings of locust auditory neurons, we show that intrinsic neuronal variability on the level of spikes is reduced with increasing temperature. We use a detailed mathematical model including stochastic ion channel gating to shed light on the underlying biophysical mechanisms in auditory receptor neurons: because of a redistribution of channel-induced current noise toward higher frequencies and specifics of the temperature dependence of the membrane impedance, membrane potential noise is indeed reduced at higher temperatures. This finding holds under generic conditions and physiologically plausible assumptions on the temperature dependence of the channels' kinetics and peak conductances. We demonstrate that the identified mechanism also can explain the experimentally observed reduction of spike timing variability at higher temperatures. PMID:26041833

  16. Evidence of short spatial variability of the equatorial electrojet at close longitudinal separation

    NASA Astrophysics Data System (ADS)

    Chandrasekhar, N. Phani; Arora, Kusumita; Nagarajan, Nandini

    2014-12-01

    The characteristics of longitudinal variability of equatorial electrojet (EEJ) and counter electrojet (CEJ), presented in this study, are based on concurrent observations from a hitherto unsampled region of the world to examine the (1) degree of correlation between hourly means and monthly averaged hourly means of ground observations with equatorial electrojet climatological model (EEJM-2.0), (2) day-to-day longitudinal variability of EEJ strength between the pairs of sites, and (3) longitudinal variability in occurrences of counter electrojet. The analyses are based on the data obtained from an observatory and three new remote sites in the northern Indian Ocean at a longitudinal separation of approximately 15°: Hyderabad (HYB) and Vencode (VEN) at 77° E and Port Blair (PBR) and Campbell Bay (CBY) at 93° E, for a period of 4 months during Lloyd's D-season (November 2011 to February 2012) and comparison with the EEJM-2.0 based on CHAMP satellite data. At both longitudes, the overall correlation of monthly mean hourly values (i.e., from 05:00 to 19:00 LT) between the observed EEJ strength and modeled current density from EEJM-2.0 is good ( r > 0.8). However, a significant lack of correlation is witnessed on day-to-day peak values (i.e., 12:00 LT) between the observed variations and the model at both sites. Further, a comparison of noontime peaks between the two sites shows a considerable day-to-day variability. A large number of CEJs (43 events) are recorded during the study: at CBY (15 events) and VEN (28 events). Analyses of the CEJ events highlight the variability of CEJ phenomena in terms of amplitude, dates, and time of occurrence over 15° longitude separation. The local nature of perturbations causing CEJ is evident; the possible factors are being non-migrating eastward and westward propagating diurnal tides and local meteorological phenomena associated with upper mesospheric temperature, wind, and density variations.

  17. Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease.

    PubMed

    Rohr, Jason R; Raffel, Thomas R

    2010-05-01

    The role of global climate change in the decline of biodiversity and the emergence of infectious diseases remains controversial, and the effect of climatic variability, in particular, has largely been ignored. For instance, it was recently revealed that the proposed link between climate change and widespread amphibian declines, putatively caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), was tenuous because it was based on a temporally confounded correlation. Here we provide temporally unconfounded evidence that global El Niño climatic events drive widespread amphibian losses in genus Atelopus via increased regional temperature variability, which can reduce amphibian defenses against pathogens. Of 26 climate variables tested, only factors associated with temperature variability could account for the spatiotemporal patterns of declines thought to be associated with Bd. Climatic predictors of declines became significant only after controlling for a pattern consistent with epidemic spread (by temporally detrending the data). This presumed spread accounted for 59% of the temporal variation in amphibian losses, whereas El Niño accounted for 59% of the remaining variation. Hence, we could account for 83% of the variation in declines with these two variables alone. Given that global climate change seems to increase temperature variability, extreme climatic events, and the strength of Central Pacific El Niño episodes, climate change might exacerbate worldwide enigmatic declines of amphibians, presumably by increasing susceptibility to disease. These results suggest that changes to temperature variability associated with climate change might be as significant to biodiversity losses and disease emergence as changes to mean temperature. PMID:20404180

  18. Linkages Between Multiscale Global Sea Surface Temperature Change and Precipitation Variabilities in the US

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Weng, Heng-Yi

    1999-01-01

    A growing number of evidence indicates that there are coherent patterns of variability in sea surface temperature (SST) anomaly not only at interannual timescales, but also at decadal-to-inter-decadal timescale and beyond. The multi-scale variabilities of SST anomaly have shown great impacts on climate. In this work, we analyze multiple timescales contained in the globally averaged SST anomaly with and their possible relationship with the summer and winter rainfall in the United States over the past four decades.

  19. Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability

    NASA Astrophysics Data System (ADS)

    Kokubo, Mitsuru

    2015-05-01

    The physical mechanisms of the quasar ultraviolet (UV)-optical variability are not well understood despite the long history of observations. Recently, Dexter & Agol presented a model of quasar UV-optical variability, which assumes large local temperature fluctuations in the quasar accretion discs. This inhomogeneous accretion disc model is claimed to describe not only the single-band variability amplitude, but also microlensing size constraints and the quasar composite spectral shape. In this work, we examine the validity of the inhomogeneous accretion disc model in the light of quasar UV-optical spectral variability by using five-band multi-epoch light curves for nearly 9 000 quasars in the Sloan Digital Sky Survey (SDSS) Stripe 82 region. By comparing the values of the intrinsic scatter σint of the two-band magnitude-magnitude plots for the SDSS quasar light curves and for the simulated light curves, we show that Dexter & Agol's inhomogeneous accretion disc model cannot explain the tight inter-band correlation often observed in the SDSS quasar light curves. This result leads us to conclude that the local temperature fluctuations in the accretion discs are not the main driver of the several years' UV-optical variability of quasars, and consequently, that the assumption that the quasar accretion discs have large localized temperature fluctuations is not preferred from the viewpoint of the UV-optical spectral variability.

  20. Internal and Forced Low-Frequency Surface Temperature Variability at Global and Regional Scales

    NASA Astrophysics Data System (ADS)

    Mann, M. E.; Steinman, B. A.; Miller, S. K.

    2014-12-01

    There is evidence for internal models of decadal and multidecadal surface temperature variability that possess relatively narrowband spectral signatures. Among these are the so-called Atlantic Multidecadal Oscillation ("AMO") and Pacific Decadal Oscillation ("PDO"). Separating these internal variability components from long-term forced temperature changes, however, is a non-trivial task. We apply a semi-empirical approach that combines climate observations and model-simulations to estimate Atlantic- and Pacific-based internal multidecadal variability (termed 'AMO' and 'PMO', respectively). Using analyses of coupled global climate model simulations, we show that our approach correctly identifies the internal variability components, while several alternative approaches overestimate and misidentify these components and their contribution to hemispheric mean temperatures. Using our method, the AMO and PMO are found to project in nearly equal proportion onto internal multidecadal variability in Northern Hemisphere mean temperature (termed 'NMO'). A recent NMO cooling trend which contributes to the slowdown or "false pause" in warming of the past decade is seen to reflect a competition between a modest positive peak in the AMO and a substantially negative-trending PMO.

  1. Associations of decadal to multidecadal sea-surface temperature variability with Upper Colorado River flow

    USGS Publications Warehouse

    McCabe, G.J.; Betancourt, J.L.; Hidalgo, H.G.

    2007-01-01

    The relations of decadal to multidecadal (D2M) variability in global sea-surface temperatures (SSTs) with D2M variability in the flow of the Upper Colorado River Basin (UCRB) are examined for the years 1906-2003. Results indicate that D2M variability of SSTs in the North Atlantic, North Pacific, tropical Pacific, and Indian Oceans is associated with D2M variability of the UCRB. A principal components analysis (with varimax rotation) of detrended and 11-year smoothed global SSTs indicates that the two leading rotated principal components (RPCs) explain 56% of the variability in the transformed SST data. The first RPC (RPC1) strongly reflects variability associated with the Atlantic Multidecadal Oscillation and the second RPC (RPC2) represents variability of the Pacific Decadal Oscillation, the tropical Pacific Ocean, and Indian Ocean SSTs. Results indicate that SSTs in the North Atlantic Ocean (RPC1) explain as much of the D2M variability in global SSTs as does the combination of Indian and Pacific Ocean variability (RPC2). These results suggest that SSTs in all of the oceans have some relation with flow of the UCRB, but the North Atlantic may have the strongest and most consistent association on D2M time scales. Hydroclimatic persistence on these time scales introduces significant nonstationarity in mean annual streamflow, with critical implications for UCRB water resource management. ?? 2007 American Water Resources Association.

  2. On the interannual variability and on trends of the temperature in the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Labitzke, K.; Naujokat, B.

    1985-07-01

    The new Reference Atmosphere presented here is based on global satellite data and forms a very useful basis for climatological studies. When using such climatologies it is important to be aware of the well known interannual variability which n themiddle atmosphere is particularly large during the northern winters and southern springs. Variability ofthe upper and lower stratospheres is discussed in detail. Areas covered included the polar region and the middile and lower latitudes. Temperature trends, notably the alteration of the global temperature structure by a number of anthropogenically influenced tract gases or the greenhouse effect is discussed.

  3. Two distinct mechanisms on East Asian surface temperature variability during summer

    NASA Astrophysics Data System (ADS)

    Yeh, Sang-Wook; Won, Yujin; Yeo, Sae-Rim; Yim, Bo Young

    2016-04-01

    The surface air temperature (SAT) in East Asia was examined in order to find global scale versus local scale factors that affected its variability during the summer (June-July-August). It was found that there exist a distinguished sub-seasonal variation, showing remarkable differences in its variability between early summer (June) and late summer (July and August). In particular, we pay attention to the variability of Korean SAT. This study revealed that Korean SAT during early and late summer is affected by different principal modes of SAT over East Asia domain. In particular, there was a significant warming trend in the Korean SAT during early summer, which was primarily influenced by a global warming trend that manifested in East Asia. Meanwhile, there exists the local scale variability of the Korean SAT, which is independent from the global warming signal. During late summer, on the other hand, the SAT variability in Korea was not significantly influenced by a warming trend, although the warming signal still accounts for majority of the SAT variance over East Asia. Instead, Korean SAT during late summer appears to be closely related to the atmospheric variability originated from the western tropical sea surface temperature (SST) forcing. These results implied that the East Asian SAT variability during early and late summer has different sources.

  4. Sea surface temperature variability in the southwest tropical Pacific since AD 1649

    NASA Astrophysics Data System (ADS)

    Delong, Kristine L.; Quinn, Terrence M.; Taylor, Frederick W.; Lin, Ke; Shen, Chuan-Chou

    2012-11-01

    A prime focus of research is differentiating the contributions of natural climate variability from those that are anthropogenically forced, especially as it relates to climate prediction. The short length of instrumental records, particularly from the South Pacific, hampers this research, specifically for investigations of decadal to centennial scale variability. Here we present a sea surface temperature (SST) reconstruction derived from highly reproducible records of strontium-to-calcium ratios (Sr/Ca) in corals from New Caledonia to investigate natural SST variability in the southwest tropical Pacific from AD 1649-1999. Our results reveal periods of warmer and colder temperatures of the order of decades during the Little Ice Age that do not correspond to long-term variations in solar irradiance or the 11-year sunspot cycle. We suggest that solar variability does not explain decadal to centennial scale SST variability in reconstructions from the southwest tropical Pacific. Our SST reconstruction covaries with the Southern Hemisphere Pacific decadal oscillation and the South Pacific decadal oscillation, from which SST anomalies in the southwest Pacific are linked to precipitation anomalies in the western tropical Pacific. We find that decadal scale SST variability has changed in strength and periodicity after 1893, suggesting a shift in natural variability for this location.

  5. Oceanographic Controls on Diffuse Flow Temperature Variability at Main Endeavour Field

    NASA Astrophysics Data System (ADS)

    Mihaly, S. F.; Matabos, M.; Butterfield, D. A.; Lee, R.; Lilley, M. D.; Sarradin, P. M.; Sarrazin, J.

    2015-12-01

    Temperature observations from the Main Endeavour vent Field (MEF) on the Endeavour segment of the Juan de Fuca Ridge reveal large spatial variability over centimeter length scales. Five thermistor chains with ten sensors each are draped over a faunal assemblage on the the north side of the Grotto mound in the northern part of MEF. Spacing is on the order of 10 cm and the areal coverage is about a square meter. Shimmering fluids are evident in the ROV video during the deployment and recovery of the thermistors indicating that the area is a diffuse venting zone. The temperature variability can be a result of heterogeneity in the degree of diffuse venting and/or variability in the degree of mixing with the cool ambient waters. Concurrent observations from the NEPTUNE cabled observatory are: temperature from a nearby hot fluid (330 deg) vent orifice that is weakly modulated by the surface tide (pressure), temperature from a diffuse flow area artificially sheltered from the ambient currents and measurements of currents from a bottom-mounted ADCP. We use these measurements to argue that the temperature variability is the result of interaction of the buoyant flow with the oceanic currents in the boundary layer at the level of the faunal assemblage.

  6. Deglacial Subsurface Temperature Change in the Tropical North Atlantic Linked to Atlantic Meridional Overturning Circulation Variability

    NASA Astrophysics Data System (ADS)

    Schmidt, M. W.; Chang, P.; Otto-Bliesner, B. L.

    2010-12-01

    Coupled ocean-atmosphere modeling experiments indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly coupled to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes (Zhang, 2007; Chang et al., 2008; and Chiang et al., 2008). While a slowdown of AMOC in these experiments results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming due to rapid reorganizations of ocean circulation patterns (Wan et al., 2009). In addition, observational records of detrended 20th century ocean temperature and salinity variability show a strong anticorrelation between surface cooling and subsurface warming in the TNA over the past several decades, suggesting changing vertical temperature gradients in this region may be a distinct fingerprint of AMOC variability (Zhang 2007). In order to test the hypothesis that subsurface temperature change in the TNA is coupled to AMOC variability across abrupt climate events over the last deglacial, we reconstructed high-resolution Mg/Ca-temperature and δ18O records from both surface (G. ruber) and sub-thermocline dwelling (G. truncatulinoides, 350-500 m depth and G. crassaformis, 450-580 m) planktonic foraminifera in the southern Caribbean Sea sediment core VM12-107 (11.33oN, 66.63oW; 1079 m; 18 cm/kyr sedimentation rate). Sea surface temperatures indicate a gradual warming in the TNA starting at ~19 kyr BP with small cold reversals of ~1.5oC during Heinrich Event 1 (H1) and the Younger Dryas (YD). In contrast, last glacial maximum subsurface temperatures were as much as 2.5oC warmer than Late Holocene values and H1 and the YD are marked by the warmest subsurface temperatures characterized by abrupt temperature increases as large as 4-5oC. Furthermore, a comparison of our subsurface temperature record with the Bermuda Rise 231Pa/230Th proxy record of AMOC variability (McManus et al., 2004) indicates a strong

  7. Interannual variability of wintertime temperature on the inner continental shelf of the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Connolly, Thomas P.; Lentz, Steven J.

    2014-09-01

    The shallow depth of the inner continental shelf allows for rapid adjustment of the ocean to air-sea exchange of heat and momentum compared with offshore locations. Observations during 2001-2013 are used to evaluate the contributions of air-sea heat flux and oceanic advection to interannual variability of inner-shelf temperature in the Middle Atlantic Bight. Wintertime processes are important for interpreting regional interannual variability at nearshore locations since winter anomalies account for 69-77% of the variance of the annual anomalies and are correlated over broad along-shelf scales, from New England to North Carolina. At the Martha's Vineyard Coastal Observatory on the 12 m isobath, a heat budget is used to test the hypothesis that interannual differences in winter temperatures are due solely to air-sea heat flux. Bimonthly averages of air-sea heat flux are correlated with temporal changes in temperature, but overestimate the observed wintertime cooling. Velocity and satellite-derived temperature data show that interannual variability in wintertime surface cooling is partially compensated for by alongshore advection of warmer water from the west at this particular location. It is also shown that surface heat flux is a strong function of air-sea temperature difference. Because of this coupling between ocean and air temperatures in shallow water, along-shelf advection can significantly modify the surface heat flux at seasonal and interannual time scales. While along-shelf advection at relatively small (˜100 km) scales can be an important component of the heat budget over the inner shelf, interannual temperature variability is still largely determined by adjustment to large-scale air-temperature anomalies.

  8. Separating the influence of temperature, drought, and fire on interannual variability in atmospheric CO2

    PubMed Central

    Keppel-Aleks, Gretchen; Wolf, Aaron S; Mu, Mingquan; Doney, Scott C; Morton, Douglas C; Kasibhatla, Prasad S; Miller, John B; Dlugokencky, Edward J; Randerson, James T

    2014-01-01

    The response of the carbon cycle in prognostic Earth system models (ESMs) contributes significant uncertainty to projections of global climate change. Quantifying contributions of known drivers of interannual variability in the growth rate of atmospheric carbon dioxide (CO2) is important for improving the representation of terrestrial ecosystem processes in these ESMs. Several recent studies have identified the temperature dependence of tropical net ecosystem exchange (NEE) as a primary driver of this variability by analyzing a single, globally averaged time series of CO2 anomalies. Here we examined how the temporal evolution of CO2 in different latitude bands may be used to separate contributions from temperature stress, drought stress, and fire emissions to CO2 variability. We developed atmospheric CO2 patterns from each of these mechanisms during 1997–2011 using an atmospheric transport model. NEE responses to temperature, NEE responses to drought, and fire emissions all contributed significantly to CO2 variability in each latitude band, suggesting that no single mechanism was the dominant driver. We found that the sum of drought and fire contributions to CO2 variability exceeded direct NEE responses to temperature in both the Northern and Southern Hemispheres. Additional sensitivity tests revealed that these contributions are masked by temporal and spatial smoothing of CO2 observations. Accounting for fires, the sensitivity of tropical NEE to temperature stress decreased by 25% to 2.9 ± 0.4 Pg C yr−1 K−1. These results underscore the need for accurate attribution of the drivers of CO2 variability prior to using contemporary observations to constrain long-term ESM responses. PMID:26074665

  9. Temperature variability in X-ray bright points observed with Hinode/XRT

    NASA Astrophysics Data System (ADS)

    Kariyappa, R.; Deluca, E. E.; Saar, S. H.; Golub, L.; Damé, L.; Pevtsov, A. A.; Varghese, B. A.

    2011-02-01

    Aims: We investigate the variability in temperature as a function of time among a sample of coronal X-ray bright points (XBPs). Methods: We analysed a 7-h (17:00-24:00 UT) long time sequence of soft X-ray images observed almost simultaneously in two filters (Ti_poly and Al_mesh) on April 14, 2007 with X-ray telescope (XRT) onboard the Hinode mission. We identified and selected 14 XBPs for a detailed analysis. The light curves of XBPs were derived using the SolarSoft library in IDL. The temperature of XBPs was determined using the calibrated temperature response curves of the two filters by means of the intensity ratio method. Results: We find that the XBPs show a high variability in their temperature and that the average temperature ranges from 1.1 MK to 3.4 MK. The variations in temperature are often correlated with changes in average X-ray emission. It is evident from the results of time series that the XBP heating rate can be highly variable on short timescales, suggesting that it has a reconnection origin.

  10. Temperature Values Variability in Piezoelectric Implant Site Preparation: Differences between Cortical and Corticocancellous Bovine Bone

    PubMed Central

    Lamazza, Luca; Garreffa, Girolamo; Laurito, Domenica; Lollobrigida, Marco; Palmieri, Luigi; De Biase, Alberto

    2016-01-01

    Purpose. Various parameters can influence temperature rise and detection during implant site preparation. The aim of this study is to investigate local temperature values in cortical and corticocancellous bovine bone during early stages of piezoelectric implant site preparation. Materials and Methods. 20 osteotomies were performed using a diamond tip (IM1s, Mectron Medical Technology, Carasco, Italy) on two different types of bovine bone samples, cortical and corticocancellous, respectively. A standardized protocol was designed to provide constant working conditions. Temperatures were measured in real time at a fixed position by a fiber optic thermometer. Results. Significantly higher drilling time (154.90 sec versus 99.00 sec; p < 0.0001) and temperatures (39.26°C versus 34.73°C; p = 0.043) were observed in the cortical group compared to the corticocancellous group. A remarkable variability of results characterized the corticocancellous blocks as compared to the blocks of pure cortical bone. Conclusion. Bone samples can influence heat generation during in vitro implant site preparation. When compared to cortical bone, corticocancellous samples present more variability in temperature values. Even controlling most experimental factors, the impact of bone samples still remains one of the main causes of temperature variability. PMID:27110567

  11. Variability of Sub-Canopy Flow, Temperature, and Horizontal Advection in Moderately Complex Terrain

    NASA Astrophysics Data System (ADS)

    Thomas, Christoph K.

    2011-04-01

    We examine the space-time structure of the wind and temperature fields, as well as that of the resulting spatial temperature gradients and horizontal advection of sensible heat, in the sub-canopy of a forest with a dense overstorey in moderately complex terrain. Data were collected from a sensor network consisting of ten stations and subject to orthogonal decomposition using the multiresolution basis set and stochastic analyses including two-point correlations, dimensional structure functions, and various other bulk measures for space and time variability. Despite some similarities, fundamental differences were found in the space-time structure of the motions dominating the variability of the sub-canopy wind and temperature fields. The dominating motions occupy similar spatial, but different temporal, scales. A conceptual space-time diagram was constructed based on the stochastic analysis that includes the important end members of the spatial and temporal scales of the observed motions of both variables. Short-lived and small-scale motions govern the variability of the wind, while the diurnal temperature oscillation driven by the surface radiative transfer is the main determinant of the variability in the temperature signal, which occupies much larger time scales. This scale mismatch renders Taylor's hypothesis for sub-canopy flow invalid and aggravates the computation of meaningful estimates of horizontal advective fluxes without dense spatial information. It may further explain the ambiguous and inconclusive results reported in numerous energy and mass balance and advection studies evaluating the hypothesis that accounting for budget components other than the change in storage term and the vertical turbulent flux improves the budget closure when turbulent diffusion is suppressed in plant canopies. Estimates of spatial temperature gradients and advective fluxes were sensitive to the network geometry and the spatial interpolation method. The assumption of linear

  12. The variability of California summertime marine stratus: impacts on surface air temperatures

    USGS Publications Warehouse

    Iacobellis, Sam F.; Cayan, Daniel R.

    2013-01-01

    This study investigates the variability of clouds, primarily marine stratus clouds, and how they are associated with surface temperature anomalies over California, especially along the coastal margin. We focus on the summer months of June to September when marine stratus are the dominant cloud type. Data used include satellite cloud reflectivity (cloud albedo) measurements, hourly surface observations of cloud cover and air temperature at coastal airports, and observed values of daily surface temperature at stations throughout California and Nevada. Much of the anomalous variability of summer clouds is organized over regional patterns that affect considerable portions of the coast, often extend hundreds of kilometers to the west and southwest over the North Pacific, and are bounded to the east by coastal mountains. The occurrence of marine stratus is positively correlated with both the strength and height of the thermal inversion that caps the marine boundary layer, with inversion base height being a key factor in determining their inland penetration. Cloud cover is strongly associated with surface temperature variations. In general, increased presence of cloud (higher cloud albedo) produces cooler daytime temperatures and warmer nighttime temperatures. Summer daytime temperature fluctuations associated with cloud cover variations typically exceed 1°C. The inversion-cloud albedo-temperature associations that occur at daily timescales are also found at seasonal timescales.

  13. Interannual and interdecadal variability in United States surface-air temperatures, 1910-87

    USGS Publications Warehouse

    Dettinger, M.D.; Ghil, M.; Keppenne, C.L.

    1995-01-01

    Monthly mean surface-air temperatures at 870 sites in the contiguous United States were analyzed for interannual and interdecadal variability over the time interval 1910-87. The temperatures were analyzed spatially by empirical-orthogonal-function analysis and temporally by singularspectrum analysis (SSA). The dominant modes of spatio-temporal variability are trends and nonperiodic variations with time scales longer than 15 years, decadal-scale oscillations with periods of roughly 7 and 10 years, and interannual oscillations of 2.2 and 3.3 years. Together, these modes contribute about 18% of the slower-than-annual United States temperature variance. Two leading components roughly capture the mean hemispheric temperature trend and represent a long-term warming, largest in the southwest, accompanied by cooling of the domain's southeastern quadrant. The extremes of the 2.2-year interannual oscillation characterize temperature differences between the Northeastern and Southwestern States, whereas the 3.3-year cycle is present mostly in the Western States. The 7- to 10-year oscillations are much less regular and persistent than the interannual oscillations and characterize temperature differences between the western and interior sectors of the United States. These continental- or regional-scale temperature variations may be related to climatic variations with similar periodicities, either global or centered in other regions; such variations include quasi-biennial oscillations over the tropical Pacific or North Atlantic and quasi-triennial oscillations of North Pacific sea-surface temperatures.

  14. The variability of California summertime marine stratus: Impacts on surface air temperatures

    NASA Astrophysics Data System (ADS)

    Iacobellis, Sam F.; Cayan, Daniel R.

    2013-08-01

    study investigates the variability of clouds, primarily marine stratus clouds, and how they are associated with surface temperature anomalies over California, especially along the coastal margin. We focus on the summer months of June to September when marine stratus are the dominant cloud type. Data used include satellite cloud reflectivity (cloud albedo) measurements, hourly surface observations of cloud cover and air temperature at coastal airports, and observed values of daily surface temperature at stations throughout California and Nevada. Much of the anomalous variability of summer clouds is organized over regional patterns that affect considerable portions of the coast, often extend hundreds of kilometers to the west and southwest over the North Pacific, and are bounded to the east by coastal mountains. The occurrence of marine stratus is positively correlated with both the strength and height of the thermal inversion that caps the marine boundary layer, with inversion base height being a key factor in determining their inland penetration. Cloud cover is strongly associated with surface temperature variations. In general, increased presence of cloud (higher cloud albedo) produces cooler daytime temperatures and warmer nighttime temperatures. Summer daytime temperature fluctuations associated with cloud cover variations typically exceed 1°C. The inversion-cloud albedo-temperature associations that occur at daily timescales are also found at seasonal timescales.

  15. Changes in Rice with Variable Temperature Parboling: Thermal and Spectroscopic Assessment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rapid visco analysis (RVA) and differential scannning calorimetry (DSC)provided overall assessments of the effects of variable temperature soaking at 30, 50, 70, and 90°C and steaming at 4, 8, and 12 min. Calculation of the relative parboiling index (RPI) and percent gelatinization provided good met...

  16. Variable-Temperature Cryostat For Radiation-Damage Testing Of Germanium Detectors

    NASA Technical Reports Server (NTRS)

    Floyd, Samuel R.; Puc, Bernard P.

    1992-01-01

    Variable-temperature cryostats developed to study radiation damage to, and annealing of, germanium gamma-ray detectors. Two styles: one accommodates large single detector and one accommodates two medium-sized detectors. New cryostats allow complete testing of large-volume germanium gamma-ray detectors without breaking cryostat vacuum and removing detectors for annealing.

  17. Temporal variability of remotely sensed suspended sediment and sea surface temperature patterns in Mobile Bay, Alabama

    USGS Publications Warehouse

    Rucker, J.B.; Stumpf, R.P.; Schroeder, W.W.

    1990-01-01

    Distribution patterns of suspended sediments and sea surface temperatures in, Mobile Bay were derived from algorithms using digital data from the visible, near infrared, and infrared channels of the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-TIROS-N satellite. Closely spaced AVHRR scenes for January 20, 24, and 29, 1982, were compared with available environmental information taken during the same period. A complex interaction between river discharge, winds, and astronomical tides controlled the distribution patterns of suspended sediments. These same variables, coupled with air temperatures, also governed the distribution patterns of sea surface temperatures. ?? 1990 Estuarine Research Federation.

  18. Spatiotemporal investigation of long-term seasonal temperature variability in Libya

    NASA Astrophysics Data System (ADS)

    Elsharkawy, S. G.; Elmallah, E. S.

    2016-09-01

    Throughout this work, spatial and temporal variations of seasonal surface air temperature have been investigated. Moreover, the effects of relative internal (teleconnection) and external (solar) forcing on surface air temperature variability have been examined. Seasonal temperature time series covering 30 different meteorological locations and lasting over the last century are considered. These locations are classified into two groups based on their spatial distribution. One represents Coast Libya Surface Air Temperature (CLSAT), contains 19 locations, and the other represents Desert Libya Surface Air Temperature (DLSAT), contains 11 locations. Average temperature departure test is applied to investigate the nature of temperature variations. Temperature trends are analyzed using the nonparametric Mann-Kendall test and their coefficients are calculated using Sen's slope estimate. Cross-correlation and spectral analysis techniques are also applied. Our results showed temperature deviation from average within a band of ± 2°C at coast region, while ± 4°C at desert region. Extreme behavior intensions between summer and winter temperatures at coast region are noticed. Segmentation process declared reversal cooling/warming behavior within temperature records for all seasons. Desert region shows warming trend for all seasons with higher coefficients than obtained at coast region. Results obtained for spectral analysis show different short and medium signals and concluded that not only the spectral properties are different for different geographical regions but also different for different climatic seasons on regional scale as well. Cross-correlation results showed that highest influence for Rz upon coastal temperature is always in conjunction with highest influence of NAO upon coastal temperature during the period 1981-2010. Desert region does not obey this phenomenon, where highest temperature-NAO correlations at desert during autumn and winter seasons are not

  19. Fingerprints of anthropogenic and natural variability in global-mean surface temperature

    SciTech Connect

    Wallace, J.M.; Zhang, Yuan

    1997-11-01

    This paper presents an analysis designed to detect greenhouse warming by distinguishing between temperature rises induced by increasing atmospheric concentrations of greenhouse gases and those induced by background variability that are present without changes in atmospheric composition. The strategy is based on the surface temperature field. At each observation time, the projection of the anomalous temperature field on the presumed anthropogenic fingerprint is removed in order to obtain a temperature deviation field; i.e., the temperature anomalies in the phase space orthogonal to the anthropogenic fingerprint, which are presumed to be entirely natural. The time series of the expansion coefficients of the fingerprint a(t) is then regressed on this temperature deviation field to identify the axis in the orthogonal phase space along which the variations are most strongly correlated, and an index n(t) of the temporal variations along that axis is generated. The index a(t) is then regressed upon n(t) and the resulting least squares fit is regarded as the component of a(t) that can be ascribed to natural causes. The analysis was performed for monthly global surface temperature anomaly fields for the period 1900-95. Results indicate that two well defined patterns of natural variability contribute to variations in global mean temperature: the synthetic cold ocean-warm land (COWL) pattern and the El Nino-Southern Oscillation (ENSO). In domains that include surface air temperature over Eurasia and North America, the COWL pattern tends to be dominant. The ENSO signature emerges as the pattern most strongly linearly correlated with global sea surface temperature and with tropospheric layer-averaged temperatures. 24 refs., 3 figs.

  20. Associations of multi-decadal sea-surface temperature variability with US drought

    USGS Publications Warehouse

    McCabe, G.J.; Betancourt, J.L.; Gray, S.T.; Palecki, M.A.; Hidalgo, H.G.

    2008-01-01

    Recent research suggests a link between drought occurrence in the conterminous United States (US) and sea surface temperature (SST) variability in both the tropical Pacific and North Atlantic Oceans on decadal to multidecadal (D2M) time scales. Results show that the Atlantic Multidecadal Oscillation (AMO) is the most consistent indicator of D2M drought variability in the conterminous US during the 20th century, but during the 19th century the tropical Pacific is a more consistent indicator of D2 M drought. The interaction between El Nin??o-Southern Oscillation (ENSO) and the AMO explain a large part of the D2M drought variability in the conterminous US. More modeling studies are needed to reveal possible mechanisms linking low-frequency ENSO variability and the AMO with drought in the conterminous US. ?? 2007 Elsevier Ltd and INQUA.

  1. Temperature, salinity, and density variability in the central Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Castelao, Renato; Glenn, Scott; Schofield, Oscar

    2010-10-01

    Four years of sustained glider observations are used to compute the seasonal cycle of hydrographic fields in the central Middle Atlantic Bight (MAB). Results reveal a large phase lag in near bottom temperatures, with peak values occurring in September at the inner shelf, in October at the mid shelf, and in November at the outer shelf. Unlike the northern MAB, the seasonal cycle explains over 70% of the near-surface salinity variability. At the inner shelf and offshore near the bottom, however, most of the variance is due to pulses in river discharge and to shifts in the position of the shelfbreak front. Cross-shelf density gradients inshore of the 60-m isobath are dominated by salinity during winter and spring, with temperature contributing significantly from August to October. This is because bottom waters near the coast are warm due to the deepening of the thermocline during fall, but offshore waters are still influenced by the cold pool. The vertical stratification seasonal variability is also large. Early in the year, stratification is small and entirely due to salinity. By May, salinity still dominates vertical gradients near the coast, but temperature and salinity contribute equally to the density stratification offshore. During summer, stratification is dominated by temperature. Temperature interannual variability was small during the sampling period, but surface salinity was anomalously low by 1.2 psu in summer 2006. The anomaly was due to larger than average discharge from the Hudson River in early summer during a period of strong upwelling favorable winds.

  2. Climate variability analysis of winter temperatures in the central Mediterranean since 1500 AD

    NASA Astrophysics Data System (ADS)

    Diodato, Nazzareno; Bellocchi, Gianni; Bertolin, Chiara; Camuffo, Dario

    2014-04-01

    This work presents the reconstruction of a time series of annual winter air temperatures across Central and Southern Italy for the period 1500-2010 that largely overlaps the Little Ice Age (LIA) period (1300-1850). A detailed analysis was undertaken on winter mean temperature data using both observations (1871-2010) and proxy-based reconstructions (1500-1870). Based on this homogeneized reconstructed series, a time-dependency in low-frequency time-pattern of temperatures (70- and 130-year cycles) was suggested although the temporal oscillation was not merely periodic. The LIA was characterized by marked climatic variability over this part of Southern Europe, with particular emphasis during the so-called "Maunder Minimum" (MM), between 1645 and 1715. The interannual variability of low temperatures, in particular, makes the MM an outstanding climatic period. There is some consistency that patterns of warming conditions observed in recent times also occurred in the past. Quasiperiodic cycles appear as a consequence of stochastic resonance emerging in long time scales but the variability inherent to the series of winter temperatures, although likely generated by processes internal to the climate system, is difficult to forecast because the system is chaotic and affected by unpredictable noise.

  3. Modes of variability of global sea surface temperature, free atmosphere temperature and oceanic surface energy flux

    SciTech Connect

    Hu, Wenjie; Newell, R.E.; Wu, Zhong-Xiang

    1994-11-01

    Monthly mean sea surface temperature (SST), free air temperature from satellite microwave sounding units (MSU) and oceanic surface energy fluxes are subjected to empirical orthogonal function (EOF) analysis for a common decade to investigate the physical relationships involved. The first seasonal modes of surface solar energy flux and SST show similar inter-hemispheric patterns with an annual cycle. Solar flux appears to control this pattern of SST. The first seasonal mode of MSU is similar with, additionally, land-sea differences; MSU is apparently partly controlled by absorption of solar near-infrared radiation and partly by sensible heat from from the land surface. The second and third seasonal eigenvector of SST and solar flux exhibit semi-annual oscillations associated with a pattern of cloudiness in the subtropics accompanying the translation of the Hadley cell rising motion between the hemispheres. The second seasonal mode of MSU is dominated by an El Nino Signal. The first nonseasonal EOFs of SST and solar flux exhibit El Nino characteristics with solar pattern being governed by west-to-east translation of a Walker cell type pattern. The first non-seasonal EOF of MSU shows a tropical strip pattern for the El Nino mode, which is well correlated with the latent heat fluxes in the tropical east Pacific but not in the tropical west Pacific. Two possible explanations are: an increase in subsidence throughout the tropical strip driven by extra evaporation in the tropical east Pacific and consequent additional latent heat liberation; a decrease of meridional heat flux out of the tropics. 56 refs., 12 figs., 5 tabs.

  4. Recent temperature variability and trends in the coastal areas of the western Svalbard

    NASA Astrophysics Data System (ADS)

    Isaksen, Ketil; Nordli, Øyvind; Przybylak, Rajmund; Wyszynski, Przemyslaw

    2015-04-01

    The Svalbard Archipelago (74°-81°N, 10°-35°E) has experienced the greatest temperature increase in Europe during the latest three decades. Svalbard is also noted for its wide year-to-year variation in monthly temperatures and weather. The project "Arctic climate system study of ocean, sea ice and glaciers interactions in Svalbard area" (AWAKE-2) is a continuation and extension of the Polish-Norwegian AWAKE project (2009-2011). The aim of the AWAKE-2 is to understand the interactions between the main components of the climate system in the Svalbard area to identify mechanisms of interannual climate variability and long-term trends. The main hypothesis is that the Atlantic Water inflows over the Svalbard shelf and into the fjords have become more frequent during the last decades due to changes in the ocean and atmosphere. The integrated effect of these events results in new regimes and changes in atmosphere, ocean, sea ice and glaciers in Svalbard. Furthermore, changes in the cryosphere create feedback effects in ocean and atmosphere. One of the objectives in the AWAKE-2 project is to study atmospheric climate variability and trends in the coastal areas of the western Svalbard. In this study we analyse the recent temperature increase and temperature variability along the western coastal areas of Svalbard and compare this to the long-term variability based on historical data. Especially focus is given to the spatial and temporal air temperature gradients along western Svalbard. Changes in possible key factors controlling the recent large temperature anomalies are discussed.

  5. Effects of outdoor temperature on changes in physiological variables before and after lunch in healthy women.

    PubMed

    Okada, Masahiro; Kakehashi, Masayuki

    2014-11-01

    Previous studies of autonomic nervous system responses before and after eating when controlling patient conditions and room temperature have provided inconsistent results. We hypothesized that several physiological parameters reflecting autonomic activity are affected by outdoor temperature before and after a meal. We measured the following physiological variables before and after a fixed meal in 53 healthy Japanese women: skin temperature, systolic and diastolic blood pressure, salivary amylase, blood glucose, heart rate, and heart rate variability. We assessed satiety before and after lunch using a visual analog scale (100 mm). We recorded outdoor temperature, atmospheric pressure, and relative humidity. Skin temperature rose significantly 1 h after eating (greater in cold weather) (P = 0.008). Cold weather markedly influenced changes in diastolic blood pressure before (P = 0.017) and after lunch (P = 0.013). Fasting salivary amylase activity increased significantly in cold weather but fell significantly after lunch (significantly greater in cold weather) (P = 0.007). Salivary amylase was significantly associated with cold weather, low atmospheric pressure, and low relative humidity 30 min after lunch (P < 0.05). Cold weather significantly influenced heart rate variability (P = 0.001). The decreased low frequency (LF)/high frequency (HF) ratio, increased Δ LF/HF ratio, and increased Δ salivary amylase activity imply that cold outdoor temperature is associated with dominant parasympathetic activity after lunch. Our results clarify the relationship between environmental factors, food intake, and autonomic system and physiological variables, which helps our understanding of homeostasis and metabolism. PMID:24599494

  6. Solar Cycle Variability in Mean Thermospheric Composition and Temperature Induced by Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    Jones, M., Jr.; Forbes, J. M.; Hagan, M. E.

    2015-12-01

    Vertically-propagating atmospheric thermal tides whose origins lie in Earth's lower atmosphere are now widely recognized as one of the dominant "meteorological" drivers of space weather. Many prior research efforts have focused on documenting and understanding the role that dissipating tides play in determining the longitudinal and seasonal variability associated with lower thermospheric winds, temperature, and constituent densities. However, considerably less attention has focused on understanding the potential solar cycle variability in the mean thermospheric state induced by the tides. In this paper we utilize the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), forced with observationally-based tides at the model lower boundary from the Climatological Tidal Model of the Thermosphere (CTMT, from Oberheide et al. [2011]), to elucidate how the dissipating tides induce variations of up to 30 K in the zonal-mean thermosphere temperature between solar minimum and maximum. Numerical experiments are performed for the month of September and for solar minimum, medium, and maximum conditions in order to quantify the solar cycle variability associated with the different terms in the thermodynamic energy, major and minor neutral constituent continuity equations. Our analysis indicates that solar cycle variability in neutral temperatures results from a combination of net eddy heat transport effects and tidal modulation of net nitric oxide (NO) cooling. The chemical and dynamical pathways through which dissipating tides affect mean NO cooling differently at solar minimum and maximum are diagnosed.

  7. Stream temperature response to variable glacier coverage in coastal watersheds of northern southeast Alaska

    NASA Astrophysics Data System (ADS)

    Hood, E. W.; Fellman, J. B.; Nagorski, S. A.; Vermilyea, A.; Pyare, S.; Scott, D.

    2012-12-01

    Glaciers in southeast Alaska are experiencing high rates of ice thinning and retreat. These ongoing changes in glacier volume are altering the proportion of streamflow derived from glacial runoff, which can be an important control on the thermal regime of streams in the region. We measured stream temperature continuously during the 2011 summer runoff season (May through October) in nine watersheds of southeast Alaska that provide spawning habitat for Pacific salmon. Six of the nine watersheds have glacier coverage ranging from 2 to 63%. Our goal was to determine how air temperature and watershed land cover, particularly glacier coverage, influence stream temperature across the seasonal hydrograph. Multiple linear regression identified mean watershed elevation, which is tied to glacier extent, and watershed lake coverage (%) as the strongest landscape controls on mean monthly stream temperature, with the weakest (May) and strongest (July) models explaining 86% and 97% of the temperature variability, respectively. Mean weekly stream temperature was significantly related to mean weekly air temperature in seven of the nine streams; however, the relationships were weak to non-significant in the streams dominated by glacial runoff. Peak summer stream temperatures occurred much earlier in the glacial streams (typically around late May) and glaciers also had a cooling effect on monthly mean stream temperature during the summer (July through September) equivalent to a decrease of 1.1°C for each 10% increase in glacier coverage. Streams with >30% glacier coverage demonstrated decreasing stream temperatures with rising summer air temperatures, while those with <30% glacier coverage exhibited summertime warming. The maximum weekly average temperature (MWAT, an index of thermal suitability for salmon species) in the six glacial streams was substantially below the lower threshold for optimum salmonid growth. This finding suggests that, while glaciers are important for

  8. Parameter Measurement and Estimation at Variable Scales: Example of Soil Temperature in Complex Terrain

    NASA Astrophysics Data System (ADS)

    Seyfried, M. S.

    2015-12-01

    The issue of matching measurement scale to application scale is long standing and frequently revisited with advances in instrumentation and computing power. In the past we have emphasized the importance of understanding the dominant processes and amount and nature of parameter variability when addressing these issues. Landscape-scale distribution of carbon and carbon fluxes is a primary focus of the Reynolds Creek Critical Zone Observatory (RC CZO). Soil temperature (Ts) is a critical parameter of generally unknown variability. Estimates of Ts are often based on air temperature (Ta), but it is understood that other factors control Ts, especially in complex terrain, where solar radiation may be a major driver. Data were collected at the Reynolds Creek Experimental Watershed (RCEW), which is 240 km2 in extent and covers a 1000 m elevation range. We used spatially extensive Ts data to evaluate correlations with Ta (915 m elevation gradient) on aspect neutral sites with similar vegetative cover. Effects of complex terrain were evaluated using a combination of fixed point measurements, fiber optic distributed temperature sensing and periodic, spatially distributed point measurements. We found that Ts over the elevation gradient followed Ta closely. However, within small subwatersheds with uniform Ta, Ts may be extremely variable, with a standard deviation of 8° C. This was strongly related to topographically associated land surface units (LSU's) and highly seasonal. Within LSU variability was generally low while there were seasonally significant differences between LSU's. The mean annual soil temperature difference between LSU's was greater than that associated with the 915 m elevation gradient. The seasonality of Ts variability was not directly related to solar radiation effects but rather to variations in cover. Scaling Ts requires high resolution accounting of topography in this environment. Spatial patterns of soil carbon at the RCEW are consistent with this.

  9. Medieval Warm Period, Little Ice Age and 20th century temperature variability from Chesapeake Bay

    USGS Publications Warehouse

    Cronin, T. M.; Dwyer, G.S.; Kamiya, T.; Schwede, S.; Willard, D.A.

    2003-01-01

    We present paleoclimate evidence for rapid (< 100 years) shifts of ??? 2-4??C in Chesapeake Bay (CB) temperature ???2100, 1600, 950, 650, 400 and 150 years before present (years BP) reconstructed from magnesium/calcium (Mg/Ca) paleothermometry. These include large temperature excursions during the Little Ice Age (???1400-1900 AD) and the Medieval Warm Period (???800-1300 AD) possibly related to changes in the strength of North Atlantic thermohaline circulation (THC). Evidence is presented for a long period of sustained regional and North Atlantic-wide warmth with low-amplitude temperature variability between ???450 and 1000 AD. In addition to centennial-scale temperature shifts, the existence of numerous temperature maxima between 2200 and 250 years BP (average ???70 years) suggests that multi-decadal processes typical of the North Atlantic Oscillation (NAO) are an inherent feature of late Holocene climate. However, late 19th and 20th century temperature extremes in Chesapeake Bay associated with NAO climate variability exceeded those of the prior 2000 years, including the interval 450-1000 AD, by 2-3??C, suggesting anomalous recent behavior of the climate system. ?? 2002 Elsevier Science B.V. All rights reserved.

  10. Water Temperature Variability Along the West Coast of the Gulf of California

    NASA Astrophysics Data System (ADS)

    God¡nez, L.; Gutierrez de Velasco, G.; Halfar, J.; Valdez, J. E.; Borges, J. M.

    2003-12-01

    The seawater temperature variability along the west coast of the Gulf of California for the time period March 2002 to March 2003 is discussed. The observations used for the analysis correspond to hourly samples at 10, 15, 20, and 25 m depths from moorings deployed in 35 m total depth at four locations along the west gulf coast, from its mouth to Ballenas channel: Cabo Pulmo (23° 23' N, 109° 25 W), Isla Espíritu Santo (24° 33' N, 110° 24' W), Punta Chivato (27° 04' N, 111° 58' W), and Bahía de los Ángeles (28° 58' N, 113° 31' W). Mean sea water temperatures increase along the gulf from the temperate north region to the subtropical gulf entrance (17 to 26° C). Temperature variability shows periodicities ranging from the seasonal to the semi-diurnal frequencies with decreasing amplitudes as frequency increases. Temperature seasonal cycle changes along the Gulf coast. Its amplitude diminishes from north to south were maximum temperature values are reached about 30 days later. Maximum and minimum values in the cycle increase northward; in contrast to the southward decreasing amplitude. Frequencies higher than seasonal exhibit two distinct patterns: An active spring and summer period and a quiet fall and winter one. During spring and summer vertical temperature differences increase and variability is dominated by 2 to 5° C amplitude oscillations at diurnal, 5 to 7 day, and quarterly frequencies. Fall and winter exhibit an almost constant vertical temperature distribution with weak oscillations (<1° C amplitude) at the same frequencies.