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Sample records for air-sea interaction experiment

  1. Joint Air Sea Interaction (JASIN) experiment, Northwest coast of Scotland

    NASA Technical Reports Server (NTRS)

    Businger, J. A.

    1981-01-01

    The joint air sea interaction (JASIN) experiment took place off the Northwest coast of Scotland. Sea surface and boundary layer parameters were measured. The JASIN data was used as ground truth for various sensors on the SEASAT satellite.

  2. Overview of the Frontal Air-Sea Interaction Experiment (FASINEX) - A study of air-sea interaction in a region of strong oceanic gradients

    NASA Technical Reports Server (NTRS)

    Weller, Robert A.

    1991-01-01

    From 1984 to 1986 the cooperative Frontal Air-Sea Interaction Experiment (FASINEX) was conducted in the subtropical convergence zone southwest of Bermuda. The overall objective of the experiment was to study air-sea interaction on 1- to 100-km horizontal scales in a region of the open ocean characterized by strong horizontal gradients in upper ocean and sea surface properties. Ocean fronts provided both large spatial gradients in sea surface temperature and strong jetlike flows in the upper ocean. The motivation for and detailed objectives of FASINEX are reviewed. Then the components of the field program are summarized. Finally, selected results are presented in order to provide an overview of the outcome of FASINEX.

  3. NASA Wallops Flight Facility Air-Sea Interaction Research Facility

    NASA Technical Reports Server (NTRS)

    Long, Steven R.

    1992-01-01

    This publication serves as an introduction to the Air-Sea Interaction Research Facility at NASA/GSFC/Wallops Flight Facility. The purpose of this publication is to provide background information on the research facility itself, including capabilities, available instrumentation, the types of experiments already done, ongoing experiments, and future plans.

  4. Air-sea interaction measurements in the west Mediterranean Sea during the Tyrrhenian Eddy Multi-Platform Observations Experiment

    SciTech Connect

    Schiano, M.E.; Santoleri, R.; Bignami, F.; Leonardi, R.M. ); Marullo, S. ); Boehm, E. )

    1993-02-15

    Measurements of radiative fluxes were carried out in the Tyrrhenian Sea in fall and winter as part of the Tyrrhenian Eddy Multi-Platform Observations Experiment (TEMPO). These measurements have supplied the first experimental radiation data set over this basin. Seasonal variation of the different components of the budget are investigated. Since data collection was carried out in an area in which a quasi-permanent eddy is present, the behavior of the radiation parameters across the frontal zone is analyzed. The most interesting result of the air-sea interaction in proximity of a marine front consists in the covariation of sea surface temperature and downwelling long-wave radiation. Contemporaneous satellite data show a clear correlation between sea surface structure and horizontal distribution of columnar atmospheric water content. Therefore this inhomogeneity clearly is one of the main factors responsible for the variation of the downwelling radiation across the front. A comparison between experimental data and results of some of the most widely used bulk formulae is carried out for both short- and long-wave radiation. The mean differnece between measured and empirical solar radiation values is less than 3%, while in the case of the net long-wave radiation budge, poor agreement is found. Indeed, a 30 W/m[sup 2] bias results from the comparison. This discrepancy is consistent with the imbalance between previous bulk calculations of total heat budget at the surface and corresponding hydrographical observations of heat exchange at Gibraltar. 30 refs., 6 figs., 9 tabs.

  5. Dependence of the microwave radar cross section on ocean surface variables - Comparison of measurements and theory using data from the Frontal Air-Sea Interaction Experiment

    NASA Technical Reports Server (NTRS)

    Weissman, David E.

    1990-01-01

    The purpose of this investigation was to study the ability of theoretical radar cross section (RCS) models to predict the absolute magnitude of the ocean radar cross section under a wide variety of sea and atmospheric conditions. The dependence of the RCS on wind stress (as opposed to wind speed) was also studied. An extensive amount of experimental data was acquired during the Frontal Air-Sea Interaction Experiment. Measurements across an ocean front demonstrated that the vertical polarization and horizontal polarization radar cross section were more strongly dependent on wind stress than on wind magnitude. Current theoretical models for the RCS, based on stress, were tested with this data. In situations where the Bragg scattering theory does not agree with the measured radar cross section (magnitude and angle dependence), revisions are hypothesized and evaluated.

  6. The relationship between the microwave radar cross section and both wind speed and stress: Model function studies using Frontal Air-Sea Interaction Experiment data

    NASA Technical Reports Server (NTRS)

    Weissman, David E.; Davidson, Kenneth L.; Brown, Robert A.; Friehe, Carl A.; Li, Fuk

    1994-01-01

    The Frontal Air-Sea Interaction Experiment (FASINEX) provided a unique data set with coincident airborne scatterometer measurements of the ocean surface radar cross section (RCS)(at Ku band) and near-surface wind and wind stress. These data have been analyzed to study new model functions which relate wind speed and surface friction velocity (square root of the kinematic wind stress) to the radar cross section and to better understand the processes in the boundary layer that have a strong influence on the radar backscatter. Studies of data from FASINEX indicate that the RCS has a different relation to the friction velocity than to the wind speed. The difference between the RCS models using these two variables depends on the polarization and the incidence angle. The radar data have been acquired from the Jet Propulsion Laboratory airborne scatterometer. These data span 10 different flight days. Stress measurements were inferred from shipboard instruments and from aircraft flying at low altitudes, closely following the scatterometer. Wide ranges of radar incidence angles and environmental conditions needed to fully develop algorithms are available from this experiment.

  7. Air-sea interaction with multiple sensors - Seasat legacy

    NASA Technical Reports Server (NTRS)

    Liu, W. T.; Tang, W.

    2003-01-01

    By flying a number of ocean observing sensors together, Seasat demonstrated potential of not only sensor synergism, but also science synergism, which has illuminated the path of spacebased air-sea interaction studies in more than two decades since its demise.

  8. Air-sea interactions and precipitation over the tropical oceans

    NASA Technical Reports Server (NTRS)

    Gautier, C.

    1992-01-01

    In this lecture, the author principally discusses air-sea exchanges that are relevant to climate and global problems. The processes of interest are those acting over time scales of months to decades, which in some instances are influenced by smaller-time-scale processes, down to the diurnal time scale. The repsective influence of these processes varies with regions, seasons and scales over which they occur and, because these processes are mostly nonlinear, scale interactions can be quite complex. Owing to the breadth of the topic addressed, the discussion is mostly focused on the tropical regions where air-sea interactions and precipitation processes eventually affect the entire globe. This allows a look in more detail at some air-sea processes, such as those associated with the El Nino southern oscillation (ENSO). This oscillation, which affects the climate of the entire globe, acts over periods of a year or longer and is caused, primarily, by sea surface temperature (SST) variations in the tropical Pacific. As a result, SST variability is often used as an indicator of coupled ocean-atmosphere low-frequency variability. Global or basin scale processes can uniquely be observed from space-born instruments with the coverage required. Space based techniques have been developed during the last decade which can now be used to illustrate the scientific issues presented and the presentation concludes with an overview of some Earth Observing System (EOS) capabilities for addressing air-sea interactions and hydrology issues.

  9. Air-Sea Interaction Measurements from R/P FLIP

    NASA Astrophysics Data System (ADS)

    Friehe, C. A.

    2002-12-01

    Soon after its inception, R/P FLIP was used to study the interaction of the atmosphere and ocean due to its unique stability and low flow distortion. A number of campaigns have been conducted to measure the surface fluxes of heat, water vapor and horizontal momentum of the wind with instrumentation as used over land, supported by the Office of Naval Research and the National Science Foundation. The size of FLIP allows for simultaneous ocean wave and mixed-layer measurements as well. Air-sea interaction was a prime component of BOMEX in 1968, where FLIP transited the Panama Canal. The methods used were similar to the over-land "Kansas" experiment of AFCRL in 1968. BOMEX was followed by many experiments in the north Pacific off San Diego, northern California, and Hawaii. Diverse results from FLIP include identification of the mechanism that causes erroneous fluctuating temperature measurements in the salt-aerosol-laden marine atmosphere, the role of humidity on optical refractive index fluctuations, and identification of Miles' critical layer in the air flow over waves.

  10. Air-sea interactions during strong winter extratropical storms

    NASA Astrophysics Data System (ADS)

    Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John

    2014-09-01

    A high-resolution, regional coupled atmosphere-ocean model is used to investigate strong air-sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air-sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air-sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere-ocean modeling framework.

  11. Research in Observations of Oceanic Air/Sea Interaction

    NASA Technical Reports Server (NTRS)

    Long, David G.; Arnold, David V.

    1995-01-01

    The primary purpose of this research has been: (1) to develop an innovative research radar scatterometer system capable of directly measuring both the radar backscatter and the small-scale and large-scale ocean wave field simultaneously and (2) deploy this instrument to collect data to support studies of air/sea interaction. The instrument has been successfully completed and deployed. The system deployment lasted for six months during 1995. Results to date suggest that the data is remarkably useful in air/sea interaction studies. While the data analysis is continuing, two journal and fifteen conference papers have been published. Six papers are currently in review with two additional journal papers scheduled for publication. Three Master's theses on this research have been completed. A Ph.D. student is currently finalizing his dissertation which should be completed by the end of the calendar year. We have received additional 'mainstream' funding from the NASA oceans branch to continue data analysis and instrument operations. We are actively pursuing results from the data expect additional publications to follow. This final report briefly describes the instrument system we developed and results to-date from the deployment. Additional detail is contained in the attached papers selected from the bibliography.

  12. The SOLAS air-sea gas exchange experiment (SAGE) 2004

    NASA Astrophysics Data System (ADS)

    Harvey, Mike J.; Law, Cliff S.; Smith, Murray J.; Hall, Julie A.; Abraham, Edward R.; Stevens, Craig L.; Hadfield, Mark G.; Ho, David T.; Ward, Brian; Archer, Stephen D.; Cainey, Jill M.; Currie, Kim I.; Devries, Dawn; Ellwood, Michael J.; Hill, Peter; Jones, Graham B.; Katz, Dave; Kuparinen, Jorma; Macaskill, Burns; Main, William; Marriner, Andrew; McGregor, John; McNeil, Craig; Minnett, Peter J.; Nodder, Scott D.; Peloquin, Jill; Pickmere, Stuart; Pinkerton, Matthew H.; Safi, Karl A.; Thompson, Rona; Walkington, Matthew; Wright, Simon W.; Ziolkowski, Lori A.

    2011-03-01

    The SOLAS air-sea gas exchange experiment (SAGE) was a multiple-objective study investigating gas-transfer processes and the influence of iron fertilisation on biologically driven gas exchange in high-nitrate low-silicic acid low-chlorophyll (HNLSiLC) Sub-Antarctic waters characteristic of the expansive subpolar zone of the southern oceans. This paper provides a general introduction and summary of the main experimental findings. The release site was selected from a pre-voyage desktop study of environmental parameters to be in the south-west Bounty Trough (46.5°S 172.5°E) to the south-east of New Zealand and the experiment was conducted between mid-March and mid-April 2004. In common with other mesoscale iron addition experiments (FeAX's), SAGE was designed as a Lagrangian study, quantifying key biological and physical drivers influencing the air-sea gas exchange processes of CO 2, DMS and other biogenic gases associated with an iron-induced phytoplankton bloom. A dual tracer SF 6/ 3He release enabled quantification of both the lateral evolution of a labelled volume (patch) of ocean and the air-sea tracer exchange at tenths of kilometer scale, in conjunction with the iron fertilisation. Estimates from the dual-tracer experiment found a quadratic dependency of the gas exchange coefficient on windspeed that is widely applicable and describe air-sea gas exchange in strong wind regimes. Within the patch, local and micrometeorological gas exchange process studies (100 m scale) and physical variables such as near-surface turbulence, temperature microstructure at the interface, wave properties and windspeed were quantified to further assist the development of gas exchange models for high-wind environments. There was a significant increase in the photosynthetic competence ( Fv/ Fm) of resident phytoplankton within the first day following iron addition, but in contrast to other FeAX's, rates of net primary production and column-integrated chlorophyll a concentrations had

  13. Tropical Cyclone Induced Air-Sea Interactions Over Oceanic Fronts

    NASA Astrophysics Data System (ADS)

    Shay, L. K.

    2012-12-01

    Recent severe tropical cyclones underscore the inherent importance of warm background ocean fronts and their interactions with the atmospheric boundary layer. Central to the question of heat and moisture fluxes, the amount of heat available to the tropical cyclone is predicated by the initial mixed layer depth and strength of the stratification that essentially set the level of entrainment mixing at the base of the mixed layer. In oceanic regimes where the ocean mixed layers are thin, shear-induced mixing tends to cool the upper ocean to form cold wakes which reduces the air-sea fluxes. This is an example of negative feedback. By contrast, in regimes where the ocean mixed layers are deep (usually along the western part of the gyres), warm water advection by the nearly steady currents reduces the levels of turbulent mixing by shear instabilities. As these strong near-inertial shears are arrested, more heat and moisture transfers are available through the enthalpy fluxes (typically 1 to 1.5 kW m-2) into the hurricane boundary layer. When tropical cyclones move into favorable or neutral atmospheric conditions, tropical cyclones have a tendency to rapidly intensify as observed over the Gulf of Mexico during Isidore and Lili in 2002, Katrina, Rita and Wilma in 2005, Dean and Felix in 2007 in the Caribbean Sea, and Earl in 2010 just north of the Caribbean Islands. To predict these tropical cyclone deepening (as well as weakening) cycles, coupled models must have ocean models with realistic ocean conditions and accurate air-sea and vertical mixing parameterizations. Thus, to constrain these models, having complete 3-D ocean profiles juxtaposed with atmospheric profiler measurements prior, during and subsequent to passage is an absolute necessity framed within regional scale satellite derived fields.

  14. Tropical Cyclone Induced Air-Sea Interactions Over Oceanic Fronts

    NASA Astrophysics Data System (ADS)

    Shay, L.

    2012-04-01

    Recent severe tropical cyclones underscore the inherent importance of warm background ocean fronts and their interactions with the atmospheric boundary layer. Central to the question of heat and moisture fluxes from the ocean to the atmosphere, the amount of heat available to the tropical cyclone is predicated by the initial depth of the mixed layer and strength of the stratification level that set the level of entrainment mixing at the base of the oceanic mixed layer. For example in oceanic regimes where the ocean mixed layers are thin, shear-induced mixing tends to cool the upper ocean (and sea surface temperatures) quickly which reduces the air-sea fluxes. This is an example of negative feedback from the ocean to the atmosphere. By contrast, in regimes where the ocean mixed layers are deep (usually along the western part of the gyres), warm water advection by the nearly steady currents reduces the levels of turbulent mixing by shear instabilities. As these strong near-inertial shears are arrested, more heat and moisture is available through the sea surface. When tropical cyclones move into favorable or neutral atmospheric conditions (low vertical shear, anticyclonic circulation aloft), tropical cyclones have a tendency to rapidly intensify as observed over the Gulf of Mexico during Isidore and Lili in 2002, Katrina and Rita in 2005, Dean and Felix in 2007 in the Caribbean Sea, and Earl in 2010 just north of the Caribbean Islands. To predict these tropical cyclone deepening (as well as weakening) cycles, coupled models must have ocean models with realistic ocean conditions and accurate air-sea and vertical mixing parameterizations. These effects and possible impact on TC deepening and weakening underscores the necessity of having complete 3-D ocean measurements juxtaposed with atmospheric profiler measurements.

  15. Diagnosing Air-Sea Interactions on Intraseasonal Timescales

    NASA Astrophysics Data System (ADS)

    DeMott, C. A.

    2014-12-01

    What is the role of ocean coupling in the Madden Julian Oscillation (MJO)? Consensus thinking holds that the essential physics of the MJO involve interactions between convection, atmospheric wave dynamics, and boundary layer and free troposphere moisture. However, many modeling studies demonstrate improved MJO simulation when an atmosphere-only general circulation model (AGCM) is coupled to an ocean model, so feedbacks from the ocean are probably not negligible. Assessing the importance and processes of these feedbacks is challenging for at least two reasons. First, observations of the MJO only sample the fully coupled ocean-atmosphere system; there is no "uncoupled" MJO in nature. Second, the practice of analyzing the MJO in uncoupled and coupled GCMs (CGCMs) involves using imperfect tools to study the problem. Although MJO simulation is improving in many models, shortcomings remain in both AGCMs and CGCMs, making it difficult to determine if changes brought about through coupling reflect critical air-sea interactions or are simply part of the collective idiosyncracies of a given model. For the atmosphere, ocean feedbacks from intraseasonal sea surface temperature (SST) variations are communicated through their effects on surface fluxes of heat and moisture. This presentation suggests a set of analysis tools for diagnosing the impact of an interactive ocean on surface latent and sensible heat fluxes, including their mean, variance, spectral characteristics, and phasing with respect to wind, SST, and MJO convection. The diagnostics are demonstrated with application to several CMIP5 models, and reveal a variety of responses to coupled ocean feedbacks.

  16. Unstable Air-Sea Interaction in the Extratropical North Atlantic

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa

    1999-01-01

    The possibility of coupled modes in the extratropical North Atlantic has fascinated the climate community since 1960's. A significant aspect of such modes is an unstable air-sea interaction, also called positive feedback, where disturbances between the atmosphere and ocean grow unbound. If a delayed response exists before the negative feedback takes effect, an oscillatory behaviour will develop. Here we explore the relationship between heat flux (positive upward) and sea surface temperature (SST). Positive feedback is characterized by a cross-correlation between the two where correlation maintains a negative sign whether SST or heat flux leads. We use model results and observations to argue that in the North Atlantic there exist regions with positive feedback. The two main locations coincide with the well-known north-south SST dipole where anomalies of opposite sign occupy areas east of Florida and north-east of Newfoundland. We show that oceanic dynamics, wave propagation and advection, give rise to oceanic anomalies in these regions. Subsequently these anomalies are amplified by atmosphere- ocean interaction: thus a positive feedback.

  17. Developments in Airborne Oceanography and Air-Sea Interaction

    NASA Astrophysics Data System (ADS)

    Melville, W. K.

    2014-12-01

    , just as aircraft carriers "project force". Now we can measure winds, waves, temperatures, currents, radiative transfer, images and air-sea fluxes from aircraft over the ocean.I will review some of the history of airborne oceanography and present examples of how it can extend our knowledge and understanding of air-sea interaction.

  18. Impacts of Air-Sea Interaction on Tropical Cyclone Track and Intensity

    NASA Technical Reports Server (NTRS)

    Wu, Liguang; Wang, Bin; Braun, Scott A.

    2004-01-01

    The influence of hurricane-ocean coupling on intensity and track of tropical cyclones (TCs) is investigated through idealized numerical experiments using a coupled hurricane-ocean model. The focus is placed on how air-sea interaction affects TC tracks and intensity. It is found that the symmetric sea surface temperature (SST) cooling is primarily responsible for the TC weakening in the coupled experiments because the induced asymmetric circulation associated with the asymmetric SST anomalies is weak and shallow. The track difference between the coupled and fixed SST experiments is generally small because of the competing processes. One is associated with the modified TC asymmetries. The asymmetric SST anomalies - weaken the surface fluxes in the rear and enhance the fluxes in the front. As a result, the enhanced diabatic heating is located on the southern side for a westward-moving TC, tending to shift the TC southward. The symmetric SST anomalies weakens the TC intensity and thus the dymmetrization process, leading to more prominent TC asymmetries. The other is associated with the weakening of the beta drift resulting from the weakening of the TC outer strength. In the coupled experiment, the weakening of the beta drift leads to a more northward shift. By adjusting the vortex outer strength of the initial vortices, the beta drift can vary while the effect of air-sea interaction changes little. Two types of track differences simulated in the previous numerical studies are obtained.

  19. A climatology of air-sea interactions at the Mediterranean LION and AZUR buoys

    NASA Astrophysics Data System (ADS)

    Caniaux, Guy; Prieur, Louis; Bouin, Marie-Noëlle; Giordani, Hervé

    2014-05-01

    The LION and AZUR buoys (respectively at 42.1°N 4.7°E and 43.4°N 7.8°E) provide an extended data set since respectively 1999 and 2001 to present for studying air-sea interactions in the northwestern Mediterranean basin. The two buoys are located where high wind events occur (resp. north western and north easterly gale winds), that force and condition deep oceanic winter convection in that region. A short-term climatology (resp. 13 and 11 years) of air-sea interactions has been developed, which includes classical meteo-oceanic parameters, but also waves period and significant wave heights and radiative fluxes. Moreover turbulent surface fluxes have been estimated from various bulk parameterizations, in order to estimate uncertainties on fluxes. An important dispersion of turbulent fluxes is found at high wind speeds according to the parameterization used, larger than taking into account the second order effects of cool skin, warm layer and waves. An important annual cycle affects air temperatures (ATs), SSTs and turbulent fluxes at the two buoys. The annual cycle of ATs and SSTs can be well reconstructed from the first two annual harmonics, while for the turbulent heat fluxes the erratic occurrence of high and low flux events, well correlated with high/dry and low windy periods, strongly affect their annual and interannual cycles. The frequency of high surface heat fluxes and high wind stress is found highest during the autumn and winter months, despite the fact that north-westerly gale winds occur all year long at LION buoy. During calm weather period, ATs and SSTs experience an important diurnal cycle (on average 1 and 0.5°C respectively), that affect latent and sensible heat fluxes. Finally, an estimate of the interannual variability of the turbulent fluxes in Autumn and Winter is discussed, in order to characterize their potential role on deep ocean convection.

  20. Air-sea interactions during strong winter extratropical storms

    USGS Publications Warehouse

    Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John

    2014-01-01

    A high-resolution, regional coupled atmosphere–ocean model is used to investigate strong air–sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air–sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air–sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere–ocean modeling framework.

  1. Western Pacific Air-Sea Interaction Study (W-PASS), Introduction and Highlights (Invited)

    NASA Astrophysics Data System (ADS)

    Tsuda, A.

    2010-12-01

    Western Pacific Air-Sea Interaction Study (W-PASS), Introduction and Highlights Atsushi Tsuda Atmosphere and Ocean Research Institute, The University of Tokyo In the western Pacific (WESTPAC) region, dust originating from Asian and Australian arid regions to the North and South Pacific, biomass burning emissions from the Southeast Asia to sub-tropical Pacific, and other anthropogenic substances are transported regionally and globally to affect cloud and rainfall patterns, air quality, and radiative budgets downwind. Deposition of these compounds into the Asian marginal seas and onto the Pacific Ocean influence surface primary productivity and species composition. In the WESTPAC region, subarctic, subtropical oceans and marginal seas are located relatively narrow latitudinal range and these areas are influenced by the dust and anthropogenic inputs. Moreover, anthropogenic emission areas are located between the arid region and the oceans. The W-PASS (Western Pacific Air-Sea interaction Study) project has been funded for 5 years as a part of SOLAS-Japan activity in the summer of 2006. We aim to resolve air-sea interaction through field observation studies mainly using research vessels and island observatories over the western Pacific. We have carried out 5 cruises to the western North Pacific focusing on air-sea interactions. Also, an intensive marine atmospheric observation including direct atmospheric deposition measurement was accomplished by a dozen W-PASS research groups at the NIES Atmospheric and Aerosol Monitoring Station of Cape Hedo in the northernmost tip of the Okinawa main Island facing the East China Sea in the spring 2008. A few weak Kosa (dust) events, anthropogenic air outflows, typical local air and occupation of marine background air were identified during the campaign period. The W-PASS has four research groups mainly focusing on VOC emissions, air-sea gas exchange processes, biogeochemical responses to dust depositions and its modeling. We also

  2. The marine boundary layer - new findings from the Östergarnsholm air-sea interaction site

    NASA Astrophysics Data System (ADS)

    Smedman, A.; Högström, U.

    2003-04-01

    From studies at the air-sea interaction site Östergarnsholm, a coherent picture of how waves interact with the atmosphere is now beginning to emerge. It is clear that the surface of the ocean behaves similar to that of a solid surface with regard to the turbulence structure in the surface layer only for conditions of pure wind sea, i.e. during the phase when waves are in the process of being built up by increasing wind. At that stage of wave development, the dominant waves are short and move slowly relative to the wind. Then the drag coefficient CDN is a function only of the wave age, expressed as u*/c_p (where u* is friction velocity and c_p is the phase velocity of the dominant waves). The relation obtained by us is identical to the corresponding expression obtained from several recent ocean experiments, Drennan et al. (2000). As soon as the wave field develops behind the "pure wind sea" stage towards conditions where relatively long waves start to gain importance, inter-actions caused by these longer waves are felt in the atmosphere at our lowest turbulence measuring height, 10 m. For example it is demonstrated that the logarithmic wind law is not valid in near-neutral conditions except when pure wind sea conditions prevail and, further that for mixed seas and swell conditions, CDN is a function not only of the wave age parameter u*/c_p but also of a second wave parameter E_1/E_2, which is a measure of the proportion of energy of relatively long waves to short waves. The neutral Stanton Number, CHN, is found to follow predictions from surface-renewal theory quite well for unstable conditions up to a wind speed of about 10 ms-1. For higher wind speed CHN increases with increasing wind speed and the interpretation is made that spray is the cause of the increase.

  3. The Influence of Tropical Air-Sea Interaction on the Climate Impact of Aerosols: A Hierarchical Modeling Approach

    NASA Astrophysics Data System (ADS)

    Hsieh, W. C.; Saravanan, R.; Chang, P.; Mahajan, S.

    2014-12-01

    In this study, we use a hierarchical modeling approach to investigate the influence of tropical air-sea feedbacks on climate impacts of aerosols in the Community Earth System Model (CESM). We construct four different models by coupling the atmospheric component of CESM, the Community Atmospheric Model (CAM), to four different ocean models: (i) the Data Ocean Model (DOM; prescribed SST), (i) Slab Ocean Model (SOM; thermodynamic coupling), (iii) Reduced Gravity Ocean Model (RGOM; dynamic coupling), and (iv) the Parallel Ocean Program (POP; full ocean model). These four models represent progressively increasing degree of coupling between the atmosphere and the ocean. The RGOM model, in particular, is tuned to produce a good simulation of ENSO and the associated tropical air-sea interaction, without being impacted by the climate drifts exhibited by fully-coupled GCMs. For each method of coupling, a pair of numerical experiments, including present day (year 2000) and preindustrial (year 1850) sulfate aerosol loading, were carried out. Our results indicate that the inclusion of air-sea interaction has large impacts on the spatial structure of the climate response induced by aerosols. In response to sulfate aerosol forcing, ITCZ shifts southwards as a result of the anomalous clockwise MMC change which transports moisture southwardly across the Equator. We present analyses of the regional response to sulfate aerosol forcing in the equatorial Pacific as well as the zonally-averaged response. The decomposition of the change in the net surface energy flux shows the most dominant terms are net shortwave radiative flux at the surface and latent heat flux. Further analyses show all ocean model simulations simulate a positive change of northward atmospheric energy transport across the Equator in response to the perturbed radiative sulfate forcing. This positive northward atmospheric energy transport change plays a role in compensating partially cooling caused by sulfate aerosols.

  4. Weak ENSO asymmetry due to weak nonlinear air-sea interaction in CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Wang, Fan; Sun, De-Zheng

    2016-03-01

    State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities. Significantly weak ENSO asymmetry and weakly nonlinear air-sea interaction over the tropical Pacific was found in CMIP5 (Coupled Model Intercomparison Project, Phase 5) climate models compared with observation. The results suggest that a weak nonlinear air-sea interaction may play a role in the weak ENSO asymmetry. Moreover, a weak nonlinearity in air-sea interaction in the models may be associated with the biases in the mean climate—the cold biases in the equatorial central Pacific. The excessive cold tongue bias pushes the deep convection far west to the western Pacific warm pool region and suppresses its development in the central equatorial Pacific. The deep convection has difficulties in further moving to the eastern equatorial Pacific, especially during extreme El Ni˜no events, which confines the westerly wind anomaly to the western Pacific. This weakens the eastern Pacific El Ni˜no events, especially the extreme El Ni˜no events, and thus leads to the weakened ENSO asymmetry in climate models. An accurate mean state structure (especially a realistic cold tongue and deep convection) is critical to reproducing ENSO events in climate models. Our evaluation also revealed that ENSO statistics in CMIP5 climate models are slightly improved compared with those of CMIP3. The weak ENSO asymmetry in CMIP5 is closer to the observation. It is more evident in CMIP5 that strong ENSO activities are usually accompanied by strong ENSO asymmetry, and the diversity of ENSO amplitude is reduced.

  5. Air-sea interaction and spatial variability of the surface evaporation duct in a coastal environment

    NASA Astrophysics Data System (ADS)

    Brooks, Ian M.

    Aircraft observations are presented of the horizontal variability in the depth of the surface evaporation duct and the relationship with the mesoscale structure of air-sea interaction processes. The 2-dimensional fields of near-surface wind, stress, wind-stress curl, air and sea-surface temperature are measured directly for flow around a headland. The sea surface temperature field indicates cold upwelling driven by the wind-stress curl. Boundary-layer stability responds rapidly to the spatial changes in surface temperature. These changes result in modification of the evaporation duct, which decreases significantly in depth over the cooler upwelling water.

  6. Impact of air-sea interaction on East Asian summer monsoon climate in WRF

    NASA Astrophysics Data System (ADS)

    Kim, Eun-Jung; Hong, Song-You

    2010-10-01

    This study investigates the effects of air-sea interaction on the simulated East Asian summer monsoon (EASM) climate in a regional climate model. An ocean mixed layer model with a revised surface roughness length formulation that was originally designed for tropical cyclone simulation and a prognostic sea surface skin temperature scheme that considers the heat budget at the water surface are systematically evaluated on the monsoonal climate over East Asia for July 2006 in the regional Weather Research and Forecasting (WRF) model. Also, 9-year (2000-2008) June-August simulations are performed to evaluate the overall impacts of these three components on the simulated EASM climatology. The 1 month simulation for July 2006 reveals that the inclusion of the ocean mixed layer model cools the water surface due to enhanced mixing, in particular, when winds are strong. Such cooling is largely compensated by the inclusion of prognostic skin temperature since solar heating in daytime overwhelms the cooling in nighttime. The revised surface roughness length effectively reduces the surface heat flux by reducing the exchange coefficients, against the conventional Charnock formula. Consideration of the three components together results in the reduction of systemic biases of excessive precipitation and weakening of the North Pacific high in the summer climate from 2000 to 2008. It is concluded that the methodology designed in this study can be an efficient way to represent the air-sea interaction in regional atmospheric models for numerical weather prediction and climate simulation.

  7. The EOSDIS Version 0 Distributed Active Archive Center for physical oceanography and air-sea interaction

    NASA Technical Reports Server (NTRS)

    Hilland, Jeffrey E.; Collins, Donald J.; Nichols, David A.

    1991-01-01

    The Distributed Active Archive Center (DAAC) at the Jet Propulsion Laboratory will support scientists specializing in physical oceanography and air-sea interaction. As part of the NASA Earth Observing System Data and Information System Version 0 the DAAC will build on existing capabilities to provide services for data product generation, archiving, distribution and management of information about data. To meet scientist's immediate needs for data, existing data sets from missions such as Seasat, Geosat, the NOAA series of satellites and the Global Positioning Satellite system will be distributed to investigators upon request. In 1992, ocean topography, wave and surface roughness data from the Topex/Poseidon radar altimeter mission will be archived and distributed. New data products will be derived from Topex/Poseidon and other sensor systems based on recommendations of the science community. In 1995, ocean wind field measurements from the NASA Scatterometer will be supported by the DAAC.

  8. Unravelling air-sea interactions driven by photochemistry in the sea-surface microlayer

    NASA Astrophysics Data System (ADS)

    George, Christian; Alpert, Peter; Tinel, Liselotte; Rossignol, Stéphanie; Perrier, Sébastien; Bernard, Francois; Ciuraru, Raluca; Hayeck, Nathalie

    2016-04-01

    Interfaces are ubiquitous in the environment, and in addition many atmospheric key processes, such as gas deposition, aerosol and cloud formation are, at one stage or the other, strongly impacted by physical- and chemical processes occurring at interfaces. Unfortunately, these processes have only been suggested and discussed but never fully addressed because they were beyond reach. We suggest now that photochemistry or photosensitized reactions exist at interfaces, and we will present and discuss their possible atmospheric implications. Obviously, one of the largest interface is the sea-surface microlayer (SML), which is a region lying at the uppermost tens to hundreds of micrometres of the water surface, with physical, chemical and biological properties that differ from those of the underlying sub-surface water. Organic film formation at the sea surface is made possible in the presence of an excess of surface-active material. Hydrophobic surfactant films are typically believed to play the role of a physical barrier to air-sea exchanges, especially at low wind speed. We will show that dissolved organic matter (DOM) can trigger photochemistry at the air-sea interface, releasing unsaturated, functionalized volatile organic compounds (VOCs), including isoprene,... acting as precursors for the formation of organic aerosols, that were thought, up to now, to be solely of biological origin! In addition, we suggest that when arranged at an air/water interface, hydrophobic surfactant can have weak chemical interactions among them, which can trigger the absorption of sunlight and can consequently induce photochemistry at such interfaces. A major question arises from such observations, namely: can the existence of such weak intra- or intermolecular interactions and the subsequent photochemistry be generalized to many other atmospheric objects such as aerosols? This topic will be presented and discussed.

  9. Gulf of Mexico Air/Sea Interaction: Measurements and Initial Data Characterization

    NASA Astrophysics Data System (ADS)

    MacDonald, C.; Huang, C. H.; Roberts, P. T.; Bariteau, L.; Fairall, C. W.; Gibson, W.; Ray, A.

    2011-12-01

    Corporate, government, and university researchers collaborated to develop an atmospheric boundary layer environmental observations program on an offshore platform in the Gulf of Mexico. The primary goals of this project were to provide data to (1) improve our understanding of boundary layer processes and air-sea interaction over the Gulf of Mexico; (2) improve regional-scale meteorological and air quality modeling; and (3) provide a framework for advanced offshore measurements to support future needs such as emergency response, exploration and lease decisions, wind energy research and development, and meteorological and air quality forecasting. In October 2010, meteorological and oceanographic sensors were deployed for an extended period (approximately 12 months) on a Chevron service platform (ST 52B, 90.5W, 29N) to collect boundary layer and sea surface data sufficient to support these objectives. This project has significant importance given the large industrial presence in the Gulf, sizeable regional population nearby, and the recognized need for precise and timely pollutant forecasts. Observations from this project include surface meteorology; sodar marine boundary layer winds; microwave radiometer profiles of temperature, relative humidity, and liquid water; ceilometer cloud base heights; water temperature and current profiles; sea surface temperature; wave height statistics; downwelling solar and infrared radiation; and air-sea turbulent momentum and heat fluxes. This project resulted in the collection of an unprecedented set of boundary layer measurements over the Gulf of Mexico that capture the range of meteorological and oceanographic interactions and processes that occur over an entire year. This presentation will provide insight into the logistical and scientific issues associated with the deployment and operations of unique measurements in offshore areas and provide results from an initial data analysis of boundary layer processes over the Gulf of

  10. Assessing Air-Sea Interaction in the Evolving NASA GEOS Model

    NASA Technical Reports Server (NTRS)

    Clayson, Carol Anne; Roberts, J. Brent

    2015-01-01

    In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. Surface heat and moisture fluxes are critical to the generation and decay of many coupled air-sea phenomena. These mechanisms operate across a number of scales and contain contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. Satellite-derived estimates of the surface turbulent and radiative heat fluxes provide an opportunity to assess results from modeling systems. Evaluation of only time mean and variability statistics, however only provides limited traceability to processes controlling what are often regime-dependent errors. This work will present an approach to evaluate the representation of the turbulent fluxes at the air-sea interface in the current and evolving Goddard Earth Observing System (GEOS) model. A temperature and moisture vertical profile-based clustering technique is used to identify robust weather regimes, and subsequently intercompare the turbulent fluxes and near-surface parameters within these regimes in both satellite estimates and GEOS-driven data sets. Both model reanalysis (MERRA) and seasonal-to-interannual coupled GEOS model simulations will be evaluated. Particular emphasis is placed on understanding the distribution of the fluxes including extremes, and the representation of near-surface forcing variables directly related to their estimation. Results from these analyses will help identify the existence and source of regime-dependent biases in the GEOS model ocean surface turbulent fluxes. The use of the temperature and moisture profiles for weather-state clustering will be highlighted for its potential broad application to 3-D output typical of model simulations.

  11. Assessing air-sea interaction in the evolving NASA GEOS model

    NASA Astrophysics Data System (ADS)

    Clayson, C. A.; Roberts, J. B.

    2014-12-01

    In order to understand how the climate responds to variations in forcing, one necessary component is to understand the full distribution of variability of exchanges of heat and moisture between the atmosphere and ocean. Surface heat and moisture fluxes are critical to the generation and decay of many coupled air-sea phenomena. These mechanisms operate across a number of scales and contain contributions from interactions between the anomalous (i.e. non-mean), often extreme-valued, flux components. Satellite-derived estimates of the surface turbulent and radiative heat fluxes provide an opportunity to assess results from modeling systems. Evaluation of only time mean and variability statistics, however only provides limited traceability to processes controlling what are often regime-dependent errors. This work will present an approach to evaluate the representation of the turbulent fluxes at the air-sea interface in the current and evolving Goddard Earth Observing System (GEOS) model. A temperature and moisture vertical profile-based clustering technique is used to identify robust weather regimes, and subsequently intercompare the turbulent fluxes and near-surface parameters within these regimes in both satellite estimates and GEOS-driven data sets. Both model reanalysis (MERRA) and seasonal-to-interannual coupled GEOS model simulations will be evaluated. Particular emphasis is placed on understanding the distribution of the fluxes including extremes, and the representation of near-surface forcing variables directly related to their estimation. Results from these analyses will help identify the existence and source of regime-dependent biases in the GEOS model ocean surface turbulent fluxes. The use of the temperature and moisture profiles for weather-state clustering will be highlighted for its potential broad application to 3-D output typical of model simulations.

  12. Second international conference on air-sea interaction and on meteorology and oceanography of the coastal zone

    SciTech Connect

    1994-12-31

    This conference was held September 22--27, 1994 in Lisbon, Portugal. The purpose of this conference was to provide a multidisciplinary forum for exchange of state-of-the-art information on air-sea interactions. Individual papers have been processed separately for inclusion in the appropriate data bases.

  13. High-resolution simulations of heavy precipitation events: role of the Adriatic SST and air-sea interactions

    NASA Astrophysics Data System (ADS)

    Davolio, Silvio; Stocchi, Paolo

    2016-04-01

    Strong Bora and Sirocco winds over the Adriatic Sea favour intense air-sea interactions and are often associated with heavy rainfall that affects the mountainous areas surrounding the basin. A convection-permitting model (MOLOCH) has been implemented at high resolution (2 km) in order to analyse several precipitation events over northern Italy, occurred during different seasons of the year and presenting different rainfall characteristics (stratiform, convective, orographic), and to possibly identify the relevant physical mechanisms involved. With the aim of assessing the impact of the sea surface temperature (SST) and surface fluxes on the intensity and location of the rainfall, sensitivity experiments have been performed taking into account the possible variability of SST analysis for model initialization. The model has been validated and specific diagnostic tools have been developed and applied to evaluate the vertically integrated moisture fluxes feeding the precipitating system or to compute a water balance in the atmosphere over the sea. The results show that the Adriatic Sea plays a role in determining the boundary layer characteristics through exchange of heat and moisture thus modifying the low-level flow dynamics and its interaction with the orography. This in turn impacts on the rainfall. Although the results vary among the analysed events, the precise definition of the SST and its evolution can be relevant for accurate precipitation forecasting.

  14. MP3 - A Meteorology and Physical Properties Package to explore Air:Sea interaction on Titan

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2012-04-01

    The exchange of mass, heat and momentum at the air:sea interface are profound influences on our environment. Titan presents us with an opportunity to study these processes in a novel physical context. The MP3 instrument, under development for the proposed Discovery mission TiME (Titan Mare Explorer) is an integrated suite of small, simple sensors that combines the a traditional meteorology package with liquid physical properties and depth-sounding. In TiME's 6-Titan-day (96-day) nominal mission, MP3 will have an extended measurement opportunity in one of the most evocative environments in the solar system. The mission and instrument benefit from APL's expertise and experience in marine as well as space systems. The topside meteorology sensors (METH, WIND, PRES, TEMP) will yield the first long-duration in-situ data to constrain Global Circulation Models. The sea sensors (TEMP, TURB, DIEL, SOSO) allow high cadence bulk composition measurements to detect heterogeneities as the TiME capsule drifts across Ligeia, while a depth sounder (SONR) will measure the bottom profile. The combination of these sensors (and vehicle dynamics, ACCL) will characterize air:sea exchange. In addition to surface data, a measurement subset (ACCL, PRES, METH, TEMP) is made during descent to characterize the structure of the polar troposphere and marine boundary layer. A single electronics box inside the vehicle performs supervising and data handling functions and is connected to the sensors on the exterior via a wire and fiber optic harness. ACCL: MEMS accelerometers and angular rate sensors measure the vehicle motion during descent and on the surface, to recover wave amplitude and period and to correct wind measurements for vehicle motion. TEMP: Precision sensors are installed at several locations above and below the 'waterline' to measure air and sea temperatures. Installation of topside sensors at several locations ensures that at least one is on the upwind side of the vehicle. PRES: The

  15. Guidelines for the air-sea interaction special study: An element of the NASA climate research program, JPL/SIO workshop report

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A program in the area of air sea interactions is introduced. A space capability is discussed for global observations of climate parameters which will contribute to the understanding of the processes which influence climate and its predictability. The following recommendations are some of the suggestions made for air sea interaction studies: (1) a major effort needs to be devoted to the preparation of space based climatic data sets; (2) NASA should create a group or center for climatic data analysis due to the substantial long term effort that is needed in research and development; (3) funding for the analyses of existing data sets should be augmented and continued beyond the termination of present programs; (4) NASA should fund studies in universities, research institutions and governments' centers; and (5) the planning for an air sea interaction mission should be an early task.

  16. Interannual Variability of South-Eastern African Summer Rainfall. Part 1: Relationships with Air-Sea Interaction Processes

    NASA Astrophysics Data System (ADS)

    Rocha, Alfredo; Simmonds, Ian

    1997-03-01

    This paper investigates the role that air-sea interaction processes may play in interannual variability of south-eastern African summer rainfall. The principal spatial modes of south-eastern African summer rainfall are first identified using principal component analysis. Four modes are retained. The most important mode of variability is found to represent rainfall variability over most of the domain, particularly in the regions to the south.The influence of ENSO (as measured by the SOI) on summer rainfall is investigated in detail for different SOI leads. The relationship is such that during the summer following the onset of an ENSO event, south-eastern Africa tends to experience dry conditions. Strongest relationships are found with the SOI leading rainfall by about 3 to 6 months.A second index, the Brandon-Marion Index (BMI) which is indicative of changes in the pressure field over the Indian Ocean correlates with rainfall better than the SOI. Strongest correlations are found when this index leads rainfall by about 1 to 3 months. More importantly, a partial correlation analysis reveals that the BMI influences rainfall independently of ENSO. Both the SOI and the BMI are potential predictors of summer rainfall.An investigation of rainfall associations with global SST anomalies reveals areas in the tropical Indian and Pacific Oceans that are linked with rainfall changes over the subcontinent. The relationship is such that warm anomalies tend to be followed by dry conditions over much of south-eastern Africa. Strongest relationships are found when SSTs lead the rainfall season by about 1 to 3 months. Well-defined atmospheric anomalies are identified during dry south-eastern African summers. These include, amongst others, anomalously warm tropospheric temperatures and marked low-level cyclonic circulation anomalies over the central Indian Ocean, which generate abnormally weak easterly winds along much of the south-eastern coast of Africa. These perturbations to the

  17. Microwave and Electro-optical Transmission Experiments in the air-sea Boundary Layer

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.

    2002-12-01

    Microwave and electro-optical signal propagation over a wind-roughened sea is strongly dependent on signal interaction with the sea surface, the mean profiles of pressure (P), humidity (Q), temperature (T), wind (U) and their turbulent fluctuations (p, q, t, u). Yet, within the marine surface layer, these mechanisms are not sufficiently understood nor has satisfactory data been taken to validate propagation models, especially under conditions of high seas, high winds, and large surface gradients of Q and T. To address this deficiency, the Rough Evaporation Duct (RED) experiment was designed to provide first data for validation of meteorological, microwave, and electro-optical models in the marine surface layer for rough surface conditions including the effects of surface waves. The RED experiment was conducted offshore of the Hawaiian Island of Oahu in late summer, mid-August to mid-September, of 2001. R/P FLIP, moored about 10 km off of the NE coast of Oahu, hosted the primary meteorological sensor suites and served as a terminus for the propagation links. There were eleven scientists and engineers aboard R/P FLIP who installed instruments measuring mean and turbulent meteorological quantities, sea wave heights, directions, and kinematics, upward and downward radiance, near surface bubble generation, atmospheric particle size distributions, laser probing of the atmosphere, and sources for both microwave and electro-optic signals. In addition to R/P FLIP, two land sites were instrumented with microwave and electro-optic receivers and meteorological sensors, two buoys were deployed, a small boat was instrumented, and two aircraft flew various tracks to sense both sea and atmospheric conditions. In all, more than 25 people from four countries, six universities, and four government agencies were directly involved with the RED experiment. While the overall outcome of the RED experiment is positive, we had a number of major and minor problems with the outfitting

  18. Experimental sea slicks: Their practical applications and utilization for basic studies of air-sea interactions

    NASA Astrophysics Data System (ADS)

    Hühnerfuss, Heinrich; Garrett, W. D.

    1981-01-01

    Practical applications of organic surface films added to the sea surface date back to ancient times. Aristotle, Plutarch, and Pliny the Elder describe the seaman's practice of calming waves in a storm by pouring oil onto the sea [Scott, 1977]. It was also noted that divers released oil beneath the water surface so that it could rise and spread over the sea surface, thereby suppressing the irritating flicker associated with the passage of light through a rippled surface. From a scientific point of view, Benjamin Franklin was the first to perform experiments with oils on natural waters. His experiment with a `teaspoonful of oil' on Clapham pond in 1773 inspired many investigators to consider sea surface phenomena or to conduct experiments with oil films. This early research has been reviewed by Giles [1969], Giles and Forrester [1970], and Scott [1977]. Franklin's studies with experimental slicks can be regarded as the beginning of surface film chemistry. His speculations on the wave damping influence of oil induced him to perform the first qualitative experiment with artificial sea slicks at Portsmouth (England) in October of 1773. Although the sea was calmed and very few white caps appeared in the oil-covered area, the swell continued through the oiled area to Franklin's great disappointment.

  19. Legacy of the Seasat mission for studies of the atmosphere and air-sea-ice interactions

    SciTech Connect

    Katsaros, K.B.; Brown, R.A. )

    1991-07-01

    Studies of midlatitude and tropical cyclones and regional weather and climate analyses are examined. Consideration is also given to studies of long swell, sea ice, and continental ice sheets with Seasat data. Many of these results of the Seasat mission were serendipitous. In preparation for the major NASA initiative for the next decade, the Earth Observing Satellite program, it was thought timely to bring some of the Seasat experiences to the fore, since valuable lessons can be learned from the successes and the failures (or omissions) of the Seasat program. Data have been obtained about: (1) the synergistic value of integrated overlapping sampling by several instruments, (2) the invaluable contribution of carefully planned surface measurements, and (3) the importance of retaining flexibility in the system (enough data retention) to allow unexpected and innovative analysis techniques. 72 refs.

  20. Decadal Air-Sea Interaction in the North Atlantic Based on Observations and Modeling Results

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa

    1998-01-01

    The decadal, 12-14 year, cycle observed in the North Atlantic SST and tide gauge data was examined using the NCEP/NCAR reanalyses, COADS data and an ocean model simulation. Besides this decadal mode, a shorter, subdecadal period of about 8 years exists in tide gauge data north of 40N, in the subpolar SST and in the winter North Atlantic Oscillation (NAO) index and in subpolar winter heat flux values. The decadal cycle is a well separated mode in a singular spectrum analysis (SSA) for a time series of SST EOF mode 1 with a center over the Gulf Stream extension. Tide gauge and SST data are consistent in that both show a significant subdecadal periodicity exclusively in the subpolar gyre, but in subtropics the 12-14 year period is the prominent, but nonstationary, decadal signal. The main finding of this study is that this 12-14 year cycle can be constructed based on the leading mode of the surface heat flux. This connection to the surface heat flux implicates the participation of the thermohaline circulation in the decadal cycle. During the cycle starting from the positive index phase of NAO, SST and oceanic heat content anomalies are created in subtropics due to local heat flux and intensification of the thermohaline circulation. The anomalies advect to the subpolar gyre where they are amplified by local heat flux and are part of the negative feedback of thermohaline circulation on itself. Consequently the oceanic thermohaline circulation slows down and the opposite cycle starts. The oscillatory nature would not be possible without the active atmospheric participation in the cycle, because it provides the unstable interaction through heat flux, without it, the oceanic mode would be damped. This analysis suggests that the two principal modes of heat flux variability, corresponding to patterns similar to North Atlantic Oscillation (NAO) and Western Atlantic (WA), are part of the same decadal cycle and an indirect measure of the north-south movement of the storm tracks.

  1. Effects of the Tibetan Plateau on the onsetof the summer monsoon in South Asia: The role of the air-sea interaction

    NASA Astrophysics Data System (ADS)

    Abe, Manabu; Hori, Masatake; Yasunari, Tetsuzo; Kitoh, Akio

    2013-02-01

    Using both a coupled atmosphere-ocean general circulation model (GCM) and an atmospheric GCM, we investigate the effects of the Tibetan Plateau (TP) on the onset of the South Asian summer monsoon by conducting simulations with and without the TP. In the coupled GCM, the presence of the TP causes the monsoon onset to occur approximately 15 days later in the Arabian Sea (AS) and India (ID) and approximately 10 days earlier in the Bay of Bengal (BB). These changes are attributed to different atmospheric circulation patterns and different conditions within the adjacent oceans, such as the AS and the BB. When the TP is included, lower sea surface temperatures (SSTs) in the AS contribute to a stable lower atmosphere, which suppresses convection over the AS and ID in May. In contrast, low pressure over South Asia, caused by the TP, induces a southwesterly toward the BB that transports a substantial amount of water vapor to the BB. This flow results in an earlier monsoon in the BB. Without the TP, higher SSTs that are formed in the AS in May destabilize the lower atmosphere and create a depression, resulting in an earlier onset of the monsoon over the AS and ID. Consequently, the cyclonic circulation spreads abruptly to the BB, and precipitation begins to increase over the BB. Therefore, the air-sea interaction in the adjacent ocean under the influence of the TP strongly modulates the onset of the South Asian summer monsoon. This modulation was verified by the atmospheric GCM experiments.

  2. The Coupled Boundary Layers and Air-Sea Transfer (CBLAST) Experiments at the Martha's Vineyard Coastal Observatory

    NASA Astrophysics Data System (ADS)

    Edson, J. B.

    2001-12-01

    The Woods Hole Oceanographic Institution (WHOI) completed the initial phase of the Martha's Vineyard Coastal Observatory (MVCO) in July of 2001. The MVCO is being using to monitor coastal atmospheric and oceanic processes. Specifically, the observatory is expected to: - Provide continuous long-term observations for climate studies. - Provide a reliable system and rugged sensors that allow opportunistic sampling of extreme events. - Provide a local climatology for intensive, short duration field campaigns. - Further facilitate regional studies of coastal processes by providing infrastructure that supports easy access to power and data. This talk provides an example of the last two objectives using the low wind component of the Office of Naval Research's (ONR) Coupled Boundary Layers and Air-Sea Transfer (CBLAST) program. CBLAST-LOW has been designed to investigate air-sea interaction and coupled atmospheric and oceanic boundary layer dynamics at low wind speeds where the dynamic processes are driven and/or strongly modulated by thermal forcing. This effort is being carried out by scientists at WHOI, NPS, NOAA, NRL, Rutgers, UW/APL, JH/APL, OSU, NCAR, and other institutions, and includes observational and modeling components. The MVCO is providing observations and infrastructure in support of several intensive operating periods in the summers of 2001, 2002, and possibly 2003. During these periods, the observational network around the observatory was and will be greatly expanded using traditional oceanographic moorings and bottom mounted instrumentation, innovative 2- and 3-D moored and drifting arrays, survey ships, AUVs, satellite remote sensing, and heavily instrumented aircraft. In addition, the MVCO cabled components will be extended out to the 20-m isobath where we plan to deploy a 35-m tower. The tower will be instrumented from 15-m above the ocean surface to the ocean bottom with instruments capable of directly measuring the momentum, heat, and radiative

  3. Hurricane-related air-sea interactions, circulation modifications, and coastal impacts on the eastern Louisiana coastline

    NASA Astrophysics Data System (ADS)

    Walker, N. D.; Pilley, C.; Li, C.; Liu, B.; Leben, R. R.; Raghunthan, V.; Ko, D.; Teague, W. J.

    2012-12-01

    Beginning in 1995, Atlantic hurricane activity increased significantly relative to the 1970s and 1980s. In 2005, records were broken when two hurricanes intensified rapidly to Category 5 for a period of time within the Gulf of Mexico, later landed, and flooded vast expanses of Louisiana's coastal regions within the span of 30 days. In this study, we investigate major hurricane events (including 2005) to elucidate air-sea interactions pertinent to hurricane intensity changes, shelf circulation, coastal flooding, and coastal land losses. We employ satellite measurements from passive sensors (temperature, true color, pigments) and active sensors (scatterometers, altimeters) in tandem with in-situ measurements from WAVCIS, NDBC, USGS, and NRL, as well as dedicated field campaigns along the coast. A selection of hurricane events during the 1998 to 2008 time period are used in this investigation. Research has shown that the Loop Current and its warm-core anticyclonic eddies (with high heat content) can intensify hurricanes transiting the Gulf; whereas, the cold-core cyclonic eddies (which are upwelling regions) can weaken hurricanes. Hurricane winds can intensify cold-core cyclonic eddies, which in some cases can impact outer shelf currents, mixing, and thermal structure throughout the water column. The exceptionally strong winds and waves in the northeast quadrant of these cyclonic atmospheric storms drive strong and long-lived westward currents. Storm surges and/or set-up of 2-6 m commonly occur along the Louisiana coastline, sometimes as a result of hurricanes traveling across the central Gulf of Mexico, at great distances from the coastal region experiencing the flooding (e.g. Hurricanes Rita and Gustav). The eastern shelf, north of the Mississippi River Birdfoot Delta, is particularly vulnerable to water level set-up and storm surge intensification due to the coastal orientation that causes the trapping of water. This area experienced land loss of 169 km2, or ~20

  4. Simulation of the Indian Summer Monsoon Using Comprehensive Atmosphere-land Interactions, in the Absence of Two-way Air-sea Interactions

    NASA Technical Reports Server (NTRS)

    Lim, Young-Kwon; Shin, D. W.; Cocke, Steven; Kang, Sung-Dae; Kim, Hae-Dong

    2011-01-01

    Community Land Model version 2 (CLM2) as a comprehensive land surface model and a simple land surface model (SLM) were coupled to an atmospheric climate model to investigate the role of land surface processes in the development and the persistence of the South Asian summer monsoon. Two-way air-sea interactions were not considered in order to identify the reproducibility of the monsoon evolution by the comprehensive land model, which includes more realistic vertical soil moisture structures, vegetation and 2-way atmosphere-land interactions at hourly intervals. In the monsoon development phase (May and June). comprehensive land-surface treatment improves the representation of atmospheric circulations and the resulting convergence/divergence through the improvements in differential heating patterns and surface energy fluxes. Coupling with CLM2 also improves the timing and spatial distribution of rainfall maxima, reducing the seasonal rainfall overestimation by approx.60 % (1.8 mm/d for SLM, 0.7 mm/dI for CLM2). As for the interannual variation of the simulated rainfall, correlation coefficients of the Indian seasonal rainfall with observation increased from 0.21 (SLM) to 0.45 (CLM2). However, in the mature monsoon phase (July to September), coupling with the CLM2 does not exhibit a clear improvement. In contrast to the development phase, latent heat flux is underestimated and sensible heat flux and surface temperature over India are markedly overestimated. In addition, the moisture fluxes do not correlate well with lower-level atmospheric convergence, yielding correlation coefficients and root mean square errors worse than those produced by coupling with the SLM. A more realistic representation of the surface temperature and energy fluxes is needed to achieve an improved simulation for the mature monsoon period.

  5. The Development of Instrumentation and Methods for Measurement of Air-Sea Interaction and Coastal Processes from Manned and Unmanned Aircraft

    NASA Astrophysics Data System (ADS)

    Reineman, Benjamin D.

    I present the development of instrumentation and methods for the measurement of coastal processes, ocean surface phenomena, and air-sea interaction in two parts. In the first, I discuss the development of a portable scanning lidar (light detection and ranging) system for manned aircraft and demonstrate its functionality for oceanographic and coastal measurements. Measurements of the Southern California coastline and nearshore surface wave fields from seventeen research flights between August 2007 and December 2008 are analyzed and discussed. The October 2007 landslide on Mt. Soledad in La Jolla, California was documented by two of the flights. The topography, lagoon, reef, and surrounding wave field of Lady Elliot Island in Australia's Great Barrier Reef were measured with the airborne scanning lidar system on eight research flights in April 2008. Applications of the system, including coastal topographic surveys, wave measurements, ship wake studies, and coral reef research, are presented and discussed. In the second part, I detail the development of instrumentation packages for small (18 -- 28 kg) unmanned aerial vehicles (UAVs) to measure momentum fluxes and latent, sensible, and radiative heat fluxes in the atmospheric boundary layer (ABL), and the surface topography. Fast-response turbulence, hygrometer, and temperature probes permit turbulent momentum and heat flux measurements, and short- and long-wave radiometers allow the determination of net radiation, surface temperature, and albedo. Careful design and testing of an accurate turbulence probe, as demonstrated in this thesis, are essential for the ability to measure momentum and scalar fluxes. The low altitude required for accurate flux measurements (typically assumed to be 30 m) is below the typical safety limit of manned research aircraft; however, it is now within the capability of small UAV platforms. Flight tests of two instrumented BAE Manta UAVs over land were conducted in January 2011 at Mc

  6. Air-sea interactions and oceanic processes in the development of different Atlantic Niño patterns

    NASA Astrophysics Data System (ADS)

    Martin-Rey, Marta; Polo, Irene; Rodríguez-Fonseca, Belén; Lazar, Alban

    2016-04-01

    Atlantic Niño is the leading mode of inter-annual variability of the tropical Atlantic basin at inter-annual time scales. A recent study has put forward that two different Atlantic Niño patterns co-exist in the tropical Atlantic basin during negative phases of the Atlantic Multidecadal Oscillation. The leading mode, Basin-Wide (BW) Atlantic Niño is characterized by an anomalous warming extended along the whole tropical basin. The second mode, the Dipolar (D) Atlantic Niño presents positive Sea Surface Temperature (SST) anomalies in the central-eastern equatorial band, surrounded by negative ones in the North and South tropical Atlantic. The BW Atlantic Niño is associated with a weakening of both Azores and Sta Helena High, which reduces the tropical trades during previous autumn-winter. On the other hand, the D-Atlantic Niño is related to a strengthening of the Azores and a weakening of Helena High given rise to a meridional Sea Level Pressure (SLP) gradient that originates an intensification of the subtropical trades and anomalous westerlies along the equatorial band. This different wind forcing suggests that different oceanic processes could act in the development of the BW and D Atlantic Niño patterns. For this reason, an inter-annual simulation with the ocean NEMO model has been performed and the heat budget analysis has been analysed for each Atlantic Niño mode. The results suggest that the two Atlantic Nino configurations have different timing. The heat budget analysis reveals that BW Atlantic Nino SST pattern is due to anomalous air-sea heat fluxes in the south tropical and western equatorial Atlantic during the autumn-winter, while vertical processes are responsible of the warming in the central and eastern part of the basin during late-winter and spring. For the D-Atlantic Nino, the subtropical cooling is attributed to turbulent heat fluxes, the equatorial SST signal is mainly forced by vertical entrainment. The role of the oceanic waves in the

  7. Air-sea interactions over Terra Nova Bay during winter: Simulation with a coupled atmosphere-polynya model

    NASA Astrophysics Data System (ADS)

    Gallée, Hubert

    A preliminary simulation of the Terra Nova Bay polynya has been performed with a coupled atmosphere-polynya model. The atmospheric model is a hydrostatic primitive equations model that has been validated previously by a simulation of the strong katabatic winds observed in that area. The polynya model includes a representation of the free drift of frazil ice and simple sea-ice dynamics and thermodynamics. Two and three-dimensional experiments have been performed under polar night conditions. Two-dimensional experiments show that an open (warm) water area influences significantly the atmospheric circulation in the antarctic coastal zone: an additional ice-breeze effect is simulated and is responsible for the strengthening of the katabatic winds near the coast. Because of the important temperature difference between the continental air and the ice-free ocean (up to 40°C), strong surface heat fluxes are simulated over the polynya. Finally, a three-dimensional experiment has been performed. The integration domain includes Terra Nova Bay. The polynya observed in that region is well simulated. It is found that heat losses from the polynya surface are stronger than previously thought but are probably constrained by the idealized representation of frazil ice, which is assumed to be uniform in each grid box. This stresses the need for having a better knowledge of frazil ice evolution in large polynyas.

  8. Enhanced Spatial & Temporal Sampling of Air/Sea Interaction with the NASA CYGNSS MicroSat Constellation

    NASA Astrophysics Data System (ADS)

    Ruf, C. S.; Ridley, A. J.; O'Brien, A.; Johnson, J.; Yi, Y.

    2013-12-01

    hardware development, a detailed end-to-end simulator has been constructed in software to reproduce the expected measurements made on orbit and, in particular, when it overflies TCs. The simulator includes realistic representations of the orbital geometries and measurement configurations of the GPS transmitting and the CYGNSS receiving satellites, a physically based electromagnetic scattering model for the surface interaction, and an accurate simulation of the on-board signal processing used to form the Level 1 science data products. Wind speed retrieval algorithms are in development. An update on the current status of the mission will be presented, with particular emphasis given to the unique spatial and temporal sampling properties that result from using a satellite constellation mission architecture.

  9. Impacts of air-sea interactions on regional air quality predictions using WRF/Chem v3.6.1 coupled with ROMS v3.7: southeastern US example

    NASA Astrophysics Data System (ADS)

    He, J.; He, R.; Zhang, Y.

    2015-11-01

    Air-sea interactions have significant impacts on coastal convection and surface fluxes exchange, which are important for the spatial and vertical distributions of air pollutants that affect public health, particularly in densely populated coastal areas. To understand the impacts of air-sea interactions on coastal air quality predictions, sensitivity simulations with different cumulus parameterization schemes and atmosphere-ocean coupling are conducted in this work over southeastern US in July 2010 using the Weather Research and Forecasting Model with Chemistry (WRF/Chem). The results show that different cumulus parameterization schemes can result in an 85 m difference in the domain averaged planetary boundary layer height (PBLH), and 4.8 mm difference in the domain averaged daily precipitation. Comparing to WRF/Chem without air-sea interactions, WRF/Chem with a 1-D ocean mixed layer model (WRF/Chem-OML) and WRF/Chem coupled with a 3-D Regional Ocean Modeling System (WRF/Chem-ROMS) predict the domain averaged changes in the sea surface temperature of 0.1 and 1.0 °C, respectively. The simulated differences in the surface concentrations of ozone (O3) and PM2.5 between WRF/Chem-ROMS and WRF/Chem can be as large as 17.3 ppb and 7.9 μg m-3, respectively. The largest changes simulated from WRF/Chem-ROMS in surface concentrations of O3 and particulate matter with diameter less than and equal to 2.5 μm (PM2.5) occur not only along coast and remote ocean, but also over some inland areas. Extensive validations against observations, show that WRF/Chem-ROMS improves the predictions of most cloud and radiative variables, and surface concentrations of some chemical species such as sulfur dioxide, nitric acid, maximum 1 h and 8 h O3, sulfate, ammonium, nitrate, and particulate matter with diameter less than and equal to 10 μm (PM10). This illustrates the benefits and needs of using coupled atmospheric-ocean model with advanced model representations of air-sea interactions for

  10. Extreme air-sea interaction over the North Atlantic subpolar gyre during the winter of 2013-2014 and its sub-surface legacy

    NASA Astrophysics Data System (ADS)

    Grist, Jeremy P.; Josey, Simon A.; Jacobs, Zoe L.; Marsh, Robert; Sinha, Bablu; Van Sebille, Erik

    2016-06-01

    Exceptionally low North American temperatures and record-breaking precipitation over the British Isles during winter 2013-2014 were interconnected by anomalous ocean evaporation over the North Atlantic subpolar gyre region (SPG). This evaporation (or oceanic latent heat release) was accompanied by strong sensible heat loss to the atmosphere. The enhanced heat loss over the SPG was caused by a combination of surface westerly winds from the North American continent and northerly winds from the Nordic Seas region that were colder, drier and stronger than normal. A distinctive feature of the air-sea exchange was that the enhanced heat loss spanned the entire width of the SPG, with evaporation anomalies intensifying in the east while sensible heat flux anomalies were slightly stronger upstream in the west. The immediate impact of the strong air-sea fluxes on the ocean-atmosphere system included a reduction in ocean heat content of the SPG and a shift in basin-scale pathways of ocean heat and atmospheric freshwater transport. Atmospheric reanalysis data and the EN4 ocean data set indicate that a longer-term legacy of the winter has been the enhanced formation of a particularly dense mode of Subpolar Mode Water (SPMW)—one of the precursors of North Atlantic Deep Water and thus an important component of the Atlantic Meridional Overturning Circulation. Using particle trajectory analysis, the likely dispersal of newly-formed SPMW is evaluated, providing evidence for the re-emergence of anomalously cold SPMW in early winter 2014/2015.

  11. Sea surface temperature anomalies, planetary waves, and air-sea feedback in the middle latitudes

    NASA Technical Reports Server (NTRS)

    Frankignoul, C.

    1985-01-01

    Current analytical models for large-scale air-sea interactions in the middle latitudes are reviewed in terms of known sea-surface temperature (SST) anomalies. The scales and strength of different atmospheric forcing mechanisms are discussed, along with the damping and feedback processes controlling the evolution of the SST. Difficulties with effective SST modeling are described in terms of the techniques and results of case studies, numerical simulations of mixed-layer variability and statistical modeling. The relationship between SST and diabatic heating anomalies is considered and a linear model is developed for the response of the stationary atmosphere to the air-sea feedback. The results obtained with linear wave models are compared with the linear model results. Finally, sample data are presented from experiments with general circulation models into which specific SST anomaly data for the middle latitudes were introduced.

  12. The Air-Sea Interface and Surface Stress under Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Soloviev, Alexander; Lukas, Roger; Donelan, Mark; Ginis, Isaac

    2013-04-01

    Air-sea interaction dramatically changes from moderate to very high wind speed conditions (Donelan et al. 2004). Unresolved physics of the air-sea interface are one of the weakest components in tropical cyclone prediction models. Rapid disruption of the air-water interface under very high wind speed conditions was reported in laboratory experiments (Koga 1981) and numerical simulations (Soloviev et al. 2012), which resembled the Kelvin-Helmholtz instability at an interface with very large density difference. Kelly (1965) demonstrated that the KH instability at the air-sea interface can develop through parametric amplification of waves. Farrell and Ioannou (2008) showed that gustiness results in the parametric KH instability of the air-sea interface, while the gusts are due to interacting waves and turbulence. The stochastic forcing enters multiplicatively in this theory and produces an exponential wave growth, augmenting the growth from the Miles (1959) theory as the turbulence level increases. Here we complement this concept by adding the effect of the two-phase environment near the mean interface, which introduces additional viscosity in the system (turning it into a rheological system). The two-phase environment includes air-bubbles and re-entering spray (spume), which eliminates a portion of the wind-wave wavenumber spectrum that is responsible for a substantial part of the air sea drag coefficient. The previously developed KH-type interfacial parameterization (Soloviev and Lukas 2010) is unified with two versions of the wave growth model. The unified parameterization in both cases exhibits the increase of the drag coefficient with wind speed until approximately 30 m/s. Above this wind speed threshold, the drag coefficient either nearly levels off or even slightly drops (for the wave growth model that accounts for the shear) and then starts again increasing above approximately 65 m/s wind speed. Remarkably, the unified parameterization reveals a local minimum

  13. Annual sea ice. An air-sea gas exchange moderator

    SciTech Connect

    Gosink, T.A.; Kelley, J.J.

    1982-01-01

    Arctic annual sea ice, particularly when it is relatively warm (> -15/sup 0/C) permits significant gas exchange between the sea and air throughout the entire year. Sea ice, particularly annual sea ice, differs from freshwater ice with respect to its permeability to gases. The presence of brine allows for significant air-sea-ice exchange of CO/sub 2/ throughout the winter, which may significantly affect the global carbon dioxide balance. Other trace gases are also noted to be enriched in sea ice, but less is known about their importance to air-sea-interactions at this time. Both physical and biological factors cause and modify evolution of gases from the surface of sea ice. Quantitative and qualitative descriptions of the nature and physical behavior of sea ice with respect to brine and gases are discussed.

  14. The potential role of sea spray droplets in facilitating air-sea gas transfer

    NASA Astrophysics Data System (ADS)

    Andreas, E. L.; Vlahos, P.; Monahan, E. C.

    2016-05-01

    For over 30 years, air-sea interaction specialists have been evaluating and parameterizing the role of whitecap bubbles in air-sea gas exchange. To our knowledge, no one, however, has studied the mirror image process of whether sea spray droplets can facilitate air-sea gas exchange. We are therefore using theory, data analysis, and numerical modeling to quantify the role of spray on air-sea gas transfer. In this, our first formal work on this subject, we seek the rate-limiting step in spray-mediated gas transfer by evaluating the three time scales that govern the exchange: τ air , which quantifies the rate of transfer between the atmospheric gas reservoir and the surface of the droplet; τ int , which quantifies the exchange rate across the air-droplet interface; and τ aq , which quantifies gas mixing within the aqueous solution droplet.

  15. Atlantic Air-Sea Interaction Revisited

    NASA Astrophysics Data System (ADS)

    Rodwell, M. J.

    INTRODUCTION DATA AND MODELS THE ANALYSIS METHOD ATMOSPHERIC FORCING OF NORTH ATLANTIC SEA SURFACE TEMPERATURES NORTH ATLANTIC SEA SURFACE TEMPERATURE FORCING OF THE ATMOSPHERE Observational Evidence Model Results POTENTIAL SEASONAL PREDICTABILITY BASED ON THE ATMOSPHERE GENERAL - CIRCULATION MODEL CONCLUSIONS AND DISCUSSION REFERENCES

  16. Atmospheric variability and air-sea interaction

    NASA Technical Reports Server (NTRS)

    Middleton, J. W.; Reiter, E. R.

    1980-01-01

    The topics studied include: (1) processing of Northern Hemispheric precipitation data, in order to fill in the transition seasons to provide a continuous 40 year data base on the variability of continental precipitation; (2) comparison of seasonally averaged fields of sea surface temperature obtained from ship observations in the North Atlantic and North Pacific in 1970 with the corresponding fields inferred from satellite observations; (3) estimation of seasonal average of total precipitable water at those admittedly few oceanic stations where repeated vertical soundings were made in 1970 and comparison with corresponding values inferred from satellite measurements; (4) comparison of seasonally averaged evaporation fields determined from ground based observations in 1970 with the field of divergence of the seasonal total horizontal water vapor flux inferred from satellite total water measurements and NMC wind data for the lower troposphere; (5) examination of meaning of convection-inversion index.

  17. Effect of Air-Sea coupling on the Frequency Distribution of Intense Tropical Cyclones over the Northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomomaki

    2016-04-01

    Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual SST variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling and hence TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.

  18. Effect of air-sea coupling on the frequency distribution of intense tropical cyclones over the northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki

    2015-12-01

    Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual sea surface temperature (SST) variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence, AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling, and hence, TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.

  19. Air-sea heat exchange, an element of the water cycle

    NASA Technical Reports Server (NTRS)

    Chahine, M. T.

    1984-01-01

    The distribution and variation of water vapor, clouds and precipitation are examined. Principal driving forces for these distributions are energy exchange and evaporation at the air-sea interface, which are also important elements of air-sea interaction studies. The overall aim of air-sea interaction studies is to quantitatively determine mass, momentum and energy fluxes, with the goal of understanding the mechanisms controlling them. The results of general circulation simulations indicate that the atmosphere in mid-latitudes responds to changes in the oceanic surface conditions in the tropics. This correlation reflects the strong interaction between tropical and mid-latitude conditions caused by the transport of heat and momentum from the tropics. Studies of air-sea exchanges involve a large number of physica, chemical and dynamical processes including heat flux, radiation, sea-surface temperature, precipitation, winds and ocean currents. The fluxes of latent heat are studied and the potential use of satellite data in determining them evaluated. Alternative ways of inferring heat fluxes will be considered.

  20. The spatial-temporal variability of air-sea momentum fluxes observed at a tidal inlet

    NASA Astrophysics Data System (ADS)

    Ortiz-Suslow, D. G.; Haus, B. K.; Williams, N. J.; Laxague, N. J. M.; Reniers, A. J. H. M.; Graber, H. C.

    2015-02-01

    Coastal waters are an aerodynamically unique environment that has been little explored from an air-sea interaction point of view. Consequently, most studies must assume that open ocean-derived parameterizations of the air-sea momentum flux are representative of the nearshore wind forcing. Observations made at the New River Inlet in North Carolina, during the Riverine and Estuarine Transport experiment (RIVET), were used to evaluate the suitability of wind speed-dependent, wind stress parameterizations in coastal waters. As part of the field campaign, a small, agile research vessel was deployed to make high-resolution wind velocity measurements in and around the tidal inlet. The eddy covariance method was employed to recover direct estimates of the 10 m neutral atmospheric drag coefficient from the three-dimensional winds. Observations of wind stress angle, near-surface currents, and heat flux were used to analyze the cross-shore variability of wind stress steering off the mean wind azimuth. In general, for onshore winds above 5 m/s, the drag coefficient was observed to be two and a half times the predicted open ocean value. Significant wind stress steering is observed within 2 km of the inlet mouth, which is observed to be correlated with the horizontal current shear. Other mechanisms such as the reduction in wave celerity or depth-limited breaking could also play a role. It was determined that outside the influence of these typical coastal processes, the open ocean parameterizations generally represent the wind stress field. The nearshore stress variability has significant implications for observations and simulations of coastal transport, circulation, mixing, and general surf-zone dynamics.

  1. In calm seas, precipitation drives air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-05-01

    In a series of experiments run in what resembles a heavily instrumented fish tank, Harrison et al. investigated the interwoven roles of wind and rain on air-sea gas exchange rates. Working with a 42-meterlong, 1-meter-wide, and 1.25-meter-tall experimental pool, the authors were able to control the wind speed, rainfall rate, water circulation speed, and other parameters, which they used to assess the effect of 24 different wind speed-rainfall rate combinations on the gas exchange rate of sulfur hexafuoride, a greenhouse gas. In trials that lasted up to 3 hours, the authors collected water samples from the tank at regular intervals, tracking the concentration of the dissolved gas.

  2. Observational Studies of Parameters Influencing Air-sea Gas Exchange

    NASA Astrophysics Data System (ADS)

    Schimpf, U.; Frew, N. M.; Bock, E. J.; Hara, T.; Garbe, C. S.; Jaehne, B.

    A physically-based modeling of the air-sea gas transfer that can be used to predict the gas transfer rates with sufficient accuracy as a function of micrometeorological parameters is still lacking. State of the art are still simple gas transfer rate/wind speed relationships. Previous measurements from Coastal Ocean Experiment in the Atlantic revealed positive correlations between mean square slope, near surface turbulent dis- sipation, and wind stress. It also demonstrated a strong negative correlation between mean square slope and the fluorescence of surface-enriched colored dissolved organic matter. Using heat as a proxy tracer for gases the exchange process at the air/water interface and the micro turbulence at the water surface can be investigated. The anal- ysis of infrared image sequences allow the determination of the net heat flux at the ocean surface, the temperature gradient across the air/sea interface and thus the heat transfer velocity and gas transfer velocity respectively. Laboratory studies were carried out in the new Heidelberg wind-wave facility AELOTRON. Direct measurements of the Schmidt number exponent were done in conjunction with classical mass balance methods to estimate the transfer velocity. The laboratory results allowed to validate the basic assumptions of the so called controlled flux technique by applying differ- ent tracers for the gas exchange in a large Schmidt number regime. Thus a modeling of the Schmidt number exponent is able to fill the gap between laboratory and field measurements field. Both, the results from the laboratory and the field measurements should be able to give a further understanding of the mechanisms controlling the trans- port processes across the aqueous boundary layer and to relate the forcing functions to parameters measured by remote sensing.

  3. New Ionospheric Interaction Experiments

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.

    2004-11-01

    Current upgrades to both the HF transmitter and diagnostic capabilities at the HAARP facility near Gakona, AK will permit a new generation ionospheric interaction experiments. We explore some of the new phenomena accessible with significantly increased ERP. Large-scale long-lived density structures induced by the HF pump in the ionospheric plasma are investigated. Long-lived density structures which convect with the ambient ionosphere, may serve as tracers for ionospheric flows and fields. Recent advances in HF and VHF radar diagnostics available for HAARP experiments, permit plasma wave detection and monitoring. We survey the mode structures expected with the next generation of high intensity experiments. Together with existing complementary diagnostics such as stimulated HF emissions and optical effects, these data will provide unprecedented views of highly nonlinear phenomena induced by high intensity RF radiation in the ionosphere.

  4. Tropical Intraseasonal Air-Sea Exchanges during the 1997 Pacific Warming

    NASA Technical Reports Server (NTRS)

    Sui, C.-H.; Lau, K.-M.; Chou, S.-H.; Wang, Zihou

    1999-01-01

    The Madden Julian Oscillations (MJO) and associated westerly wind (WW) events account for much of the tropical intraseasonal variability (TISV). The TISV has been suggested as an important stochastic forcing that may be one of the underlying causes for the observed irregularities of the El Nino-Southern Oscillation (ENSO). Recent observational studies and theories of interannual to interdecadal-scale variability suggest that ENSO may arise from different mechanisms depending on the basic states. The Pacific warming event of 1997, being associated with a period of strong MJO and WW events, serves as a natural experiment for studying the possible role of TISV in triggering an ENSO event. We have performed a combined statistical and composite analysis of surface WW events based on the assimilated surface wind and sea level pressure for the period of 1980-1993, the SSM/I wind for the period of 1988-1997, and OLR. Results indicates that extratropical forcing contribute significantly to the evolution of MJO and establishment of WW events over the Pacific warm pool. Following the major WW events, there appeared an eastward extension of equatorial warm SST anomalies from the western Pacific warm pool. Such tropical-extratropical interaction is particularly clear in the winter of 96-97 that leads to the recent warming event in 1997/98. From the above discussion, our current study on this subject is based on the hypothesis that 1) there is an enhanced air-sea interaction associated with TISV and the northerly surges from the extratropics in the initial phase of the 97/98 warming event, and 2) the relevant mechanisms are functions of the basic state of the coupled system (in terms of SST distribution and atmospheric mean circulation) that varies at the interannual and interdecadal time scale. We are analyzing the space-time structure of the northerly surges, their association with air-sea fluxes and upper ocean responses during the period of September 1996 to June 1997. The

  5. Air-sea coupling in the Hawaiian Archipelago

    NASA Astrophysics Data System (ADS)

    Souza, J. M.; Powell, B.; Mattheus, D.

    2014-12-01

    A coupled numerical model is used to investigate the ocean-atmosphere interaction in the lee of the Hawaiian archipelago. The wind curl generated by the island blocking of the trade winds is known to give rise to ocean eddies; however, the impact of the sea surface temperature (SST) and velocity fronts associated with these eddies on the atmosphere is less understood. The main coupling mechanisms are: (i) changes in the near-surface stability and surface stress, (ii) vertical transfer of momentum from higher atmospheric levels to the ocean surface due to an increase of the turbulence in the boundary layer, (iii) secondary circulations associated with perturbations in the surface atmospheric pressure over the SST fronts, and (iv) the impact of the oceanic eddy currents on the net momentum transferred between the atmosphere and the ocean. To assess the relative contribution from each process, a coupled simulation between the Regional Ocean Modeling System (ROMS) and the Weather Research and Forecasting (WRF) models is conducted for the main Hawaiian Islands. The impact of the coupling, the perturbation of the mean wind pattern, and the different spatial scales involved in the air-sea exchanges of momentum and heat are explored.

  6. Sensitivity of Air-sea Exchange In A Regional Scale Coupled Ice/ocean/atmosphere Model

    NASA Astrophysics Data System (ADS)

    Schrum, C.; Hübner, U.; Jacob, D.; Podzun, R.

    The sub-systems ice, ocean and atmosphere are coupled on the global as well as the regional scale. However, regional coupled modeling is only in the beginning, full cou- pled models which are able to describe the interaction on the regional scale and the feedback mechanism are rare at the moment. For the North Sea and the Baltic Sea such a coupled model has been developed and exemplary integrated over a full seasonal cy- cle. By comparison of different regionalization studies the impact of the regional at- mospheric modeling and coupling on the air sea fluxes have been investigated. It was shown that the regionalization as well as the coupling show strong influence on the air/sea fluxes and thus on the oceanic conditions. Further problems in regional mod- eling like the description of storm track variability and its influence on the regional ocean model were identified.

  7. The relationship between ocean surface turbulence and air-sea gas transfer velocity: An in-situ evaluation

    NASA Astrophysics Data System (ADS)

    Esters, L.; Landwehr, S.; Sutherland, G.; Bell, T. G.; Saltzman, E. S.; Christensen, K. H.; Miller, S. D.; Ward, B.

    2016-05-01

    Although the air-sea gas transfer velocity k is usually parameterized with wind speed, the so-called small-eddy model suggests a relationship between k and ocean surface dissipation of turbulent kinetic energy ɛ. Laboratory and field measurements of k and ɛ have shown that this model holds in various ecosystems. Here, field observations are presented supporting the theoretical model in the open ocean. These observations are based on measurements from the Air-Sea Interaction Profiler and eddy covariance CO2 and DMS air-sea flux data collected during the Knorr11 cruise. We show that the model results can be improved when applying a variable Schmidt number exponent compared to a commonly used constant value of 1/2. Scaling ɛ to the viscous sublayer allows us to investigate the model at different depths and to expand its applicability for more extensive data sets.

  8. Air-sea transfer of gas phase controlled compounds

    NASA Astrophysics Data System (ADS)

    Yang, M.; Bell, T. G.; Blomquist, B. W.; Fairall, C. W.; Brooks, I. M.; Nightingale, P. D.

    2016-05-01

    Gases in the atmosphere/ocean have solubility that spans several orders of magnitude. Resistance in the molecular sublayer on the waterside limits the air-sea exchange of sparingly soluble gases such as SF6 and CO2. In contrast, both aerodynamic and molecular diffusive resistances on the airside limit the exchange of highly soluble gases (as well as heat). Here we present direct measurements of air-sea methanol and acetone transfer from two open cruises: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The transfer of the highly soluble methanol is essentially completely airside controlled, while the less soluble acetone is subject to both airside and waterside resistances. Both compounds were measured concurrently using a proton-transfer-reaction mass spectrometer, with their fluxes quantified by the eddy covariance method. Up to a wind speed of 15 m s-1, observed air-sea transfer velocities of these two gases are largely consistent with the expected near linear wind speed dependence. Measured acetone transfer velocity is ∼30% lower than that of methanol, which is primarily due to the lower solubility of acetone. From this difference we estimate the “zero bubble” waterside transfer velocity, which agrees fairly well with interfacial gas transfer velocities predicted by the COARE model. At wind speeds above 15 m s-1, the transfer velocities of both compounds are lower than expected in the mean. Air-sea transfer of sensible heat (also airside controlled) also appears to be reduced at wind speeds over 20 m s-1. During these conditions, large waves and abundant whitecaps generate large amounts of sea spray, which is predicted to alter heat transfer and could also affect the air-sea exchange of soluble trace gases. We make an order of magnitude estimate for the impacts of sea spray on air-sea methanol transfer.

  9. Intense air-sea exchange and heavy rainfall: impact of the northern Adriatic SST

    NASA Astrophysics Data System (ADS)

    Stocchi, P.; Davolio, S.

    2016-02-01

    Over the northern Adriatic basin, intense air-sea interactions are often associated with heavy precipitation over the mountainous areas surrounding the basin. In this study, a high-resolution mesoscale model is employed to simulate three severe weather events and to evaluate the effect of the sea surface temperature on the intensity and location of heavy rainfall. The sensitivity tests show that the impact of SST varies among the events and it mainly involves the modification of the PBL characteristics and thus the flow dynamics and its interaction with the orography.

  10. Spatio-temporal visualization of air-sea CO2 flux and carbon budget using volume rendering

    NASA Astrophysics Data System (ADS)

    Du, Zhenhong; Fang, Lei; Bai, Yan; Zhang, Feng; Liu, Renyi

    2015-04-01

    This paper presents a novel visualization method to show the spatio-temporal dynamics of carbon sinks and sources, and carbon fluxes in the ocean carbon cycle. The air-sea carbon budget and its process of accumulation are demonstrated in the spatial dimension, while the distribution pattern and variation of CO2 flux are expressed by color changes. In this way, we unite spatial and temporal characteristics of satellite data through visualization. A GPU-based direct volume rendering technique using half-angle slicing is adopted to dynamically visualize the released or absorbed CO2 gas with shadow effects. A data model is designed to generate four-dimensional (4D) data from satellite-derived air-sea CO2 flux products, and an out-of-core scheduling strategy is also proposed for on-the-fly rendering of time series of satellite data. The presented 4D visualization method is implemented on graphics cards with vertex, geometry and fragment shaders. It provides a visually realistic simulation and user interaction for real-time rendering. This approach has been integrated into the Information System of Ocean Satellite Monitoring for Air-sea CO2 Flux (IssCO2) for the research and assessment of air-sea CO2 flux in the China Seas.

  11. Impacts of air-sea exchange coefficients on snowfall events over the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Kang, Jung-Yoon; Kwon, Young Cheol

    2016-08-01

    Snowfall over the Korean Peninsula is mainly associated with air mass transformation by the fluxes across the air-sea interface during cold-air outbreaks over the warm Yellow Sea. The heat and momentum exchange coefficients in the surface flux parameterization are key parameters of flux calculations across the air-sea interface. This study investigates the effects of the air-sea exchange coefficients on the simulations of snowfall events over the Korean Peninsula using the Weather Research and Forecasting (WRF) model. Two snowfall cases are selected for this study. One is a heavy snowfall event that took place on January 4, 2010, and the other is a light snowfall event that occurred on December 23-24, 2011. Several sensitivity tests are carried out with increased and decreased heat and momentum exchange coefficients. The domain-averaged precipitation is increased (decreased) with increased (decreased) heat exchange coefficient because the increased (decreased) surface heat flux leads to more (less) moist conditions in the low level of the atmosphere. On the other hand, the domain-averaged precipitation is decreased (increased) with increased (decreased) momentum exchange coefficient because the increased (decreased) momentum coefficient causes reduction (increase) of wind speed and heat flux. The variation of precipitation in the heat exchange coefficient experiments is much larger than that in the momentum exchange coefficient experiments because the change of heat flux has a more direct impact on moisture flux and snowfall amount, while the change of momentum flux has a rather indirect impact via wind speed changes. The low-pressure system is intensified and moves toward North when the heat exchange coefficient is increased because warming and moistening of the lower atmosphere contributes to destabilize the air mass, resulting in the change of precipitation pattern over the Korean Peninsula in the heat exchange coefficient experiments.

  12. Observational Buoy Studies of Coastal Air-Sea Fluxes.

    NASA Astrophysics Data System (ADS)

    Frederickson, Paul A.; Davidson, Kenneth L.

    2003-02-01

    Recent advancements in measurement and analysis techniques have allowed air-sea fluxes to be measured directly from moving platforms at sea relatively easily. These advances should lead to improved surface flux parameterizations, and thus to improved coupled atmosphere-ocean modeling. The Naval Postgraduate School has developed a `flux buoy' (FB) that directly measures air-sea fluxes, mean meteorological parameters, and one-dimensional and directional wave spectra. In this study, the FB instrumentation and data analysis techniques are described, and the data collected during two U.S. east coast buoy deployments are used to examine the impact of atmospheric and surface wave properties on air-sea momentum transfer in coastal ocean regions. Data obtained off Duck, North Carolina, clearly show that, for a given wind speed, neutral drag coefficients in offshore winds are higher than those in onshore winds. Offshore wind drag coefficients observed over the wind speed range from 5 to 21 m s1 were modeled equally well by a linear regression on wind speed, and a Charnock model with a constant of 0.016. Measurements from an FB deployment off Wallops Island, Virginia, show that neutral drag coefficients in onshore winds increase as the wind-wave direction differences increase, especially beyond ±60°.

  13. Climatic impacts of stochastic fluctuations in air-sea fluxes

    NASA Astrophysics Data System (ADS)

    Williams, Paul D.

    2012-05-01

    Air-sea fluxes vary partly on scales that are too small or fast to be resolved explicitly by global climate models. This paper proposes a nonlinear physical mechanism by which stochastic fluctuations in the air-sea buoyancy flux may modify the mean climate. The paper then demonstrates the mechanism in climate simulations with a comprehensive coupled general circulation model. Significant changes are detected in the time-mean oceanic mixed-layer depth, sea-surface temperature, atmospheric Hadley circulation, and net upward water flux at the sea surface. Also, El Niño Southern Oscillation (ENSO) variability is significantly increased. The findings demonstrate that noise-induced drift and noise-enhanced variability, which are familiar concepts from simple climate models, continue to apply in comprehensive climate models with millions of degrees of freedom. The findings also suggest that the lack of representation of sub-grid variability in air-sea fluxes may contribute to some of the biases exhibited by contemporary climate models.

  14. Biofilm-like properties of the sea surface and predicted effects on air-sea CO2 exchange

    NASA Astrophysics Data System (ADS)

    Wurl, Oliver; Stolle, Christian; Van Thuoc, Chu; The Thu, Pham; Mari, Xavier

    2016-05-01

    Because the sea surface controls various interactions between the ocean and the atmosphere, it has a profound function for marine biogeochemistry and climate regulation. The sea surface is the gateway for the exchange of climate-relevant gases, heat and particles. Thus, in order to determine how the ocean and the atmosphere interact and respond to environmental changes on a global scale, the characterization and understanding of the sea surface are essential. The uppermost part of the water column is defined as the sea-surface microlayer and experiences strong spatial and temporal dynamics, mainly due to meteorological forcing. Wave-damped areas at the sea surface are caused by the accumulation of surface-active organic material and are defined as slicks. Natural slicks are observed frequently but their biogeochemical properties are poorly understood. In the present study, we found up to 40 times more transparent exopolymer particles (TEP), the foundation of any biofilm, in slicks compared to the underlying bulk water at multiple stations in the North Pacific, South China Sea, and Baltic Sea. We found a significant lower enrichment of TEP (up to 6) in non-slick sea surfaces compared to its underlying bulk water. Moreover, slicks were characterized by a large microbial biomass, another shared feature with conventional biofilms on solid surfaces. Compared to non-slick samples (avg. pairwise similarity of 70%), the community composition of bacteria in slicks was increasingly (avg. pairwise similarity of 45%) different from bulk water communities, indicating that the TEP-matrix creates specific environments for its inhabitants. We, therefore, conclude that slicks can feature biofilm-like properties with the excessive accumulation of particles and microbes. We also assessed the potential distribution and frequency of slick-formation in coastal and oceanic regions, and their effect on air-sea CO2 exchange based on literature data. We estimate that slicks can reduce CO2

  15. Air-sea interaction with SSM/I and altimeter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A number of important developments in satellite remote sensing techniques have occurred recently which offer the possibility of studying over vast areas of the ocean the temporally evolving energy exchange between the ocean and the atmosphere. Commencing in spring of 1985, passive and active microwave sensors that can provide valuable data for scientific utilization will start to become operational on Department of Defense (DOD) missions. The passive microwave radiometer can be used to estimate surface wind speed, total air column humidity, and rain rate. The active radar, or altimeter, senses surface gravity wave height and surface wind speed.

  16. Air-Sea Interaction Measurements from the Controlled Towed Vehicle

    NASA Astrophysics Data System (ADS)

    Khelif, D.; Bluth, R. T.; Jonsson, H.; Barge, J.

    2014-12-01

    The Controlled Towed Vehicle (CTV) uses improved towed drone technology to actively maintain via a radar altimeter and controllable wing a user-set height that can be as low as the canonical reference height of 10 m above the sea surface. After take-off, the drone is released from the tow aircraft on a ~700-m stainless steel cable. We have instrumented the 0.23 m diameter and 2.13 m long drone with high fidelity instruments to measure the means and turbulent fluctuations of 3-D wind vector, temperature, humidity, pressure, CO2 and IR sea surface temperature. Data are recorded internally at 40 Hz and simultaneously transmitted to the tow aircraft via dedicated wireless Ethernet link. The CTV accommodates 40 kg of instrument payload and provides it with 250 W of continuous power through a ram air propeller-driven generator. Therefore its endurance is only limited by that of the tow aircraft.We will discuss the CTV development, the engineering challenges and solutions that have been successfully implemented to overcome them. We present results from recent flights as low as 9 m over the coastal ocean and comparisons of profiles and turbulent fluxes from the CTV and the tow aircraft. Manned aircraft operation at low-level boundary-layer flights is very limited. Dropsondes and UAS (Unmanned Aerial Systems) and UAS are alternates for measurements near the ocean surface. However, dropsondes have limited sensor capability and do not measure fluxes, and most present UAS vehicles do not have the payload and power capacity nor the low-flying ability in high winds over the oceans. The CTV therefore, fills a needed gap between the dropsondes, in situ aircraft, and UAS. The payload, capacity and power of the CTV makes it suitable for a variety of atmospheric research measurements. Other sensors to measure aerosol, chemistry, radiation, etc., could be readily accommodated in the CTV.

  17. Air-sea interaction in the tropical Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Allison, L. J.; Steranka, J.; Holub, R. J.; Hansen, J.; Godshall, F. A.; Prabhakara, C.

    1972-01-01

    Charts of 3-month sea surface temperature (SST) anomalies in the eastern tropical Pacific Ocean were produced for the period 1949 to 1970. The anomalies along the United States and South American west coasts and in the eastern tropical Pacific appeared to be oscillating in phase during this period. Similarly, the satellite-derived cloudiness for each of four quadrants of the Pacific Ocean (130 deg E to 100 deg W, 30 deg N to 25 deg S) appeared to be oscillating in phase. In addition, a global tropical cloudiness oscillation from 30 deg N to 30 deg S was noted from 1965 to 1970, by using monthly satellite television nephanalyses. The SST anomalies were found to have a good degree of correlation both positive and negative with the following monthly geophysical parameters: (1) satellite-derived cloudiness, (2) strength of the North and South Pacific semipermanent anticyclones, (3) tropical Pacific island rainfall, and (4) Darwin surface pressure. Several strong direct local and crossequatorial relationships were noted. In particular, the high degree of correlation between the tropical island rainfall and the SST anomalies (r = +0.93) permitted the derivation of SST's for the tropical Pacific back to 1905. The close occurrence of cold tropical SST and North Pacific 700-mb positive height anomalies with central United States drought conditions was noted.

  18. Satellite observations of air-sea interaction over the Kuroshio

    NASA Astrophysics Data System (ADS)

    Xie, S.; Nonaka, M.; Hafner, J.; Liu, W. T.

    2002-12-01

    Satellite microwave measurements are analyzed, revealing robust co-variability in sea surface temperature (SST) and wind speed over the Kuroshio and its Extension (KE). Ocean hydrodynamic instabilities cause the KE to meander and result into large SST variations. Increased (reduced) wind speeds are found to be associated with warm (cold) SST anomalies. This positive SST-wind correlation in KE is confirmed by in-situ buoy measurements and is consistent with a vertical shear adjustment mechanism. Namely, an increase in SST reduces the static stability of the near-surface atmosphere, intensifying the vertical turbulence mixing and bringing fast-moving air from aloft to the sea surface. South of Japan, the Kuroshio is known to vary between nearshore and offshore paths. Both paths seem semi-permanent and can persist months to years. As the Kuroshio shifts its path, coherent wind changes are detected. In particular, winds are high south of Tokyo when the Kuroshio takes the nearshore path while they are greatly reduced when this warm current leaves the coast in the offshore path. Further upstream in the East China Sea, on the warmer flank of the Kuroshio Front, there are a zone of high wind speed and a band of raining cloud due to the region's unstable atmospheric stratification near the surface. Surface wind convergence is roughly collocated with the Kuroshio Current. By increasing the baroclinicity and condensational heating, the Kuroshio Front aids the growth of the so-called Taiwan cyclone, an important winter weather phenomenon for Japan. The positive SST-wind correlation over the strong Kuroshio Current and its extension is opposite to the negative one often observed in regions of weak currents such as south of the Aleutian low that is considered to be indicative of atmosphere-to-ocean forcing.

  19. CLOUDS, AEROSOLS, RADIATION AND THE AIR-SEA INTERFACE OF THE SOUTHERN OCEAN: ESTABLISHING DIRECTIONS FOR FUTURE RESEARCH

    SciTech Connect

    Wood, Robert; Bretherton, Chris; McFarquhar, Greg; Protat, Alain; Quinn, Patricia; Siems, Steven; Jakob, Christian; Alexander, Simon; Weller, Bob

    2014-09-29

    A workshop sponsored by the Department of Energy was convened at the University of Washington to discuss the state of knowledge of clouds, aerosols and air-sea interaction over the Southern Ocean and to identify strategies for reducing uncertainties in their representation in global and regional models. The Southern Ocean plays a critical role in the global climate system and is a unique pristine environment, yet other than from satellite, there have been sparse observations of clouds, aerosols, radiation and the air-sea interface in this region. Consequently, much is unknown about atmospheric and oceanographic processes and their linkage in this region. Approximately 60 scientists, including graduate students, postdoctoral fellows and senior researchers working in atmospheric and oceanic sciences at U.S. and foreign universities and government laboratories, attended the Southern Ocean Workshop. It began with a day of scientific talks, partly in plenary and partly in two parallel sessions, discussing the current state of the science for clouds, aerosols and air-sea interaction in the Southern Ocean. After the talks, attendees broke into two working groups; one focused on clouds and meteorology, and one focused on aerosols and their interactions with clouds. This was followed by more plenary discussion to synthesize the two working group discussions and to consider possible plans for organized activities to study clouds, aerosols and the air-sea interface in the Southern Ocean. The agenda and talk slides, including short summaries of the highlights of the parallel session talks developed by the session chars, are available at http://www.atmos.washington.edu/socrates/presentations/SouthernOceanPresentations/.

  20. Surfactant control of air-sea gas exchange across contrasting biogeochemical regimes

    NASA Astrophysics Data System (ADS)

    Pereira, Ryan; Schneider-Zapp, Klaus; Upstill-Goddard, Robert

    2014-05-01

    Air-sea gas exchange is important to the global partitioning of CO2.Exchange fluxes are products of an air-sea gas concentration difference, ΔC, and a gas transfer velocity, kw. The latter is controlled by the rate of turbulent diffusion at the air-sea interface but it cannot be directly measured and has a high uncertainty that is now considered one of the greatest challenges to quantifying net global air-sea CO2 exchange ...(Takahashi et al., 2009). One important control on kw is exerted by sea surface surfactants that arise both naturally from biological processes and through anthropogenic activity. They influence gas exchange in two fundamental ways: as a monolayer physical barrier and through modifying sea surface hydrodynamics and hence turbulent energy transfer. These effects have been demonstrated in the laboratory with artificial surfactants ...(Bock et al., 1999; Goldman et al., 1988) and through purposeful surfactant releases in coastal waters .(.).........().(Brockmann et al., 1982) and in the open ocean (Salter et al., 2011). Suppression of kwin these field experiments was ~5-55%. While changes in both total surfactant concentration and the composition of the natural surfactant pool might be expected to impact kw, the required in-situ studies are lacking. New data collected from the coastal North Sea in 2012-2013 shows significant spatio-temporal variability in the surfactant activity of organic matter within the sea surface microlayer that ranges from 0.07-0.94 mg/L T-X-100 (AC voltammetry). The surfactant activities show a strong winter/summer seasonal bias and general decrease in concentration with increasing distance from the coastline possibly associated with changing terrestrial vs. phytoplankton sources. Gas exchange experiments of this seawater using a novel laboratory tank and gas tracers (CH4 and SF6) demonstrate a 12-45% reduction in kw compared to surfactant-free water. Seasonally there is higher gas exchange suppression in the summer

  1. Impact of Sea Spray on Air-Sea Fluxes

    NASA Astrophysics Data System (ADS)

    Veron, Fabrice; Mueller, James

    2013-11-01

    The contributions of sea spray drops to the total air-sea exchanges of momentum, heat, and mass remain an open question. A number of factors obscure any simple quantification of their contribution: the number of drops formed at the ocean surface and the per-drop contribution to the fluxes. To estimate these per-droplet fluxes, we present results from a large number of drop trajectories, which are simulated with a recently developed Lagrangian Stochastic model adapted for the heavy drop transport and evaporation within the marine boundary layer. Then, using commonly accepted spray generation functions we present estimates of spray fluxes which account for the mediating feedback effects from the droplets on the atmosphere. The results suggest that common simplifications in previous sea spray models, such as the residence time in the marine boundary layer, may not be appropriate. We further show that the spray fluxes may be especially sensitive to the size distribution of the drops. The total effective air-sea fluxes lead to drag and enthalpy coefficients that increase modestly with wind speed. The rate of increase for the drag coefficient is greatest at moderate wind speeds, while the rate of increase for the enthalpy coefficient is greatest at higher wind speeds. Funded by grants OCE-0850663 and OCE-0748767 from the National Science Foundation.

  2. The role of bubbles during air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Emerson, Steven; Bushinsky, Seth

    2016-06-01

    The potential for using the air-sea exchange rate of oxygen as a tracer for net community biological production in the ocean is greatly enhanced by recent accuracy improvements for in situ measurements of oxygen on unmanned platforms. A limiting factor for determining the exchange process is evaluating the air-sea flux contributed by bubble processes produced by breaking waves, particularly during winter months under high winds. Highly accurate measurements of noble gases (Ne, Ar & Kr) and nitrogen, N2, in seawater are tracers of the importance of bubble process in the surface mixed layer. We use measured distributions of these gases in the ventilated thermocline of the North Pacific and an annual time series of N2 in the surface ocean of the NE Subarctic Pacific to evaluate four different air-water exchange models chosen to represent the range of model interpretation of bubble processes. We find that models must have an explicit bubble mechanism to reproduce concentrations of insoluble atmospheric gases, but there are periods when they all depart from observations. The recent model of Liang et al. (2013) stems from a highly resolved model of bubble plumes and categorizes bubble mechanisms into those that are small enough to collapse and larger ones that exchange gases before they resurface, both of which are necessary to explain the data.

  3. Evaluation of the swell effect on the air-sea gas transfer in the coastal zone

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Loza, Lucía; Ocampo-Torres, Francisco J.

    2016-04-01

    Air-sea gas transfer processes are one of the most important factors regarding global climate and long-term global climate changes. Despite its importance, there is still a huge uncertainty on how to better parametrize these processes in order to include them on the global climate models. This uncertainty exposes the need to increase our knowledge on gas transfer controlling mechanisms. In the coastal regions, breaking waves become a key factor to take into account when estimating gas fluxes, however, there is still a lack of information and the influence of the ocean surface waves on the air-sea interaction and gas flux behavior must be validated. In this study, as part of the "Sea Surface Roughness as Air-Sea Interaction Control" project, we evaluate the effect of the ocean surface waves on the gas exchange in the coastal zone. Direct estimates of the flux of CO2 (FCO2) and water vapor (FH2O) through eddy covariance, were carried out from May 2014 to April 2015 in a coastal station located at the Northwest of Todos Santos Bay, Baja California, México. For the same period, ocean surface waves are recorded using an Acoustic Doppler Current Profiler (Workhorse Sentinel, Teledyne RD Instruments) with a sampling rate of 2 Hz and located at 10 m depth about 350 m away from the tower. We found the study area to be a weak sink of CO2 under moderate wind and wave conditions with a mean flux of -1.32 μmol/m2s. The correlation between the wind speed and FCO2 was found to be weak, suggesting that other physical processes besides wind may be important factors for the gas exchange modulation at coastal waters. The results of the quantile regression analysis computed between FCO2 and (1) wind speed, (2) significant wave height, (3) wave steepness and (4) water temperature, show that the significant wave height is the most correlated parameter with FCO2; Nevertheless, the behavior of their relation varies along the probability distribution of FCO2, with the linear regression

  4. A SOLAS challenge: How can we test test feedback loops involving air-sea exchange?

    NASA Astrophysics Data System (ADS)

    Huebert, B. J.

    2004-12-01

    It is now well accepted that the Earth System links biological and physical processes in the water, on land, and in the air, creating countless feedback loops and dependencies that are at best difficult to quantify. One example of interest to SOLAS scientists is the suspension and long-range transport of dust from Asia, which may or may not interact with acidic air pollutants, that may increase the biological availability of iron, thereby increasing primary productivity in parts of the Pacific. This could increase DMS emissions and modify the radiative impact of Pacific clouds, affecting the climate and the hydrological system that limits the amount of dust lofted each year. Air-sea exchange is central to many such feedbacks: Variations in productivity in upwelling waters off Peru probably change DMS emissions and modify the stratocumulus clouds that blanket that region, thereby feeding back to productivity. The disparate time and space scales of the controlling processes make it difficult to observationally constrain such systems without the use of multi-year time-series and intensive multiplatform process studies. Unfortunately, much of the infrastructure for funding Earth science is poorly suited for supporting multidisciplinary research. For example, NSF's program managers are organized into disciplines and sub-disciplines, and rely on disciplinary reviewer communities that are protective of their slices of the funding pie. It is easy to find authors of strong, innovative, cross-disciplinary (yet unsuccessful) proposals who say they'll never try it again, because there is so little institutional support for interfacial research. Facility issues also complicate multidisciplinary projects, since there are usually several allocating groups that don't want to commit their ships, airplanes, or towers until the other groups have done so. The result is that there are very few examples of major interdisciplinary projects, even though IGBP core programs have articulated

  5. Air-Sea Exchange Of CO2: A Multi-Technology Approach

    NASA Astrophysics Data System (ADS)

    Tengberg, A.; Almroth, E.; Anderson, L.; Hall, P.; Hjalmarsson, S.; Lefevre, D.; Omstedt, A.; Rutgersson, A.; Sahlee, E.; Smedman, A.; Wesslander, K.

    2006-12-01

    We report on experiences and results from a multidisciplinary project in which we try to elucidate the complex processes involved in air-sea exchange of CO2. This study was performed in the Baltic Sea (off the Swedish island Gotland) and combined the following technologies: - Meteorological measurements of wind, turbulence, temperature, humidity, humidity flux, CO2 and CO2 flux at several levels from a fixed observation tower - Hourly PCO2 measurements with a moored automatic instrument - Collection of dissolved oxygen, temperature, salinity and turbidity data at different levels in the water column at 1-minute intervals - Daily light (PAR) and primary production measurements obtained with a moored automatic incubator - Daily primary production measurements using manual methods - Use of an acoustic current profiler to collect water column information on currents, turbulence, water level and waves - Repetitive water column profiles, from a ship, of dissolved inorganic carbon, oxygen, nutrients, alkalinity, pH, PAR, Chlorophyll A, salinity and temperature

  6. Transition from downward to upward air-sea momentum transfer in swell-dominated light wind condition

    NASA Astrophysics Data System (ADS)

    Smedman, Ann-Sofi; Högström, Ulf; Rutgersson, Anna

    2016-04-01

    Atmospheric and surface wave data from two oceanic experiments carried out on FLIP and ASIS platforms are analysed in order to identify swell-related effects on the momentum exchange during low wind speed conditions. The RED experiment was carried out on board an R/P Floating Instrument Platform, FLIP, anchored north east of the Hawaiian island Oahu with sonic anemometers at four levels: 5.1 m, 6.9 m, 9.9 m and 13.8 m respectively. The meteorological conditions were characterized by north- easterly trade wind and with swell present during most of the time. During swell the momentum flux was directed downwards meaning a positive contribution to the stress. The FETCH experiment was carried out in the Gulf of Lion in the north-western Mediterranean Sea. On the ASIS (air-sea interaction spar) buoy a sonic anemometer was mounted at 7 m above the mean surface level. During strong swell conditions the momentum flux was directed upwards meaning a negative contribution to the stress in this case. The downward momentum flux is shown to be a function of the orbital circulation while the upward momentum flux is a function of wave height. The dividing wind speed is found to be 3.5 m/s Conclusion: Wind speed > 3.5 m/s creates waves (ripples) and thus roughness. Combination of orbital motion and asymmetric structure of ripples lead to flow perturbation and downward transport of negative momentum. With low wind speed (no ripples but viscosity) circulations will form above the crest and the trough with opposite direction which will cause a pressure drop in the vertical direction and an upward momentum transport from the water to the air.

  7. Experiments in interactive panoramic cinema

    NASA Astrophysics Data System (ADS)

    Fisher, Scott S.; Anderson, Steve; Ruiz, Susana; Naimark, Michael; Hoberman, Perry; Bolas, Mark; Weinberg, Richard

    2005-03-01

    For most of the past 100 years, cinema has been the premier medium for defining and expressing relations to the visible world. However, cinematic spectacles delivered in darkened theaters are predicated on a denial of both the body and the physical surroundings of the spectators who are watching it. To overcome these deficiencies, filmmakers have historically turned to narrative, seducing audiences with compelling stories and providing realistic characters with whom to identify. This paper describes several research projects in interactive panoramic cinema that attempt to sidestep the narrative preoccupations of conventional cinema and instead are based on notions of space, movement and embodied spectatorship rather than traditional storytelling. Example projects include interactive works developed with the use of a unique 360 degree camera and editing system, and also development of panoramic imagery for a large projection environment with 14 screens on 3 adjacent walls in a 5-4-5 configuration with observations and findings from an experiment projecting panoramic video on 12 of the 14, in a 4-4-4 270 degree configuration.

  8. Compact optical system for imaging underwater and through the air/sea interface

    NASA Astrophysics Data System (ADS)

    Alley, Derek; Mullen, Linda; Laux, Alan

    2012-06-01

    Typical line-of-sight (LOS)/monostatic optical imaging systems include a laser source and receiver that are co-located on the same platform. The performance of such systems is deteriorated in turbid ocean water due to the large amount of light that is scattered on the path to and from an object of interest. Imagery collected with the LOS/monostatic system through the air/sea interface is also distorted due to wave focusing/defocusing effects. The approach of this project is to investigate an alternate, non-line-of-sight (NLOS)/bistatic approach that offers some advantages over these traditional LOS/monostatic imaging techniques. In this NLOS system the laser and receiver are located on separate platforms with the laser located closer to the object of interest. As the laser sequentially scans the underwater object, a time-varying intensity signal corresponding to reflectivity changes in the object is detected by the distant receiver. A modulated laser illuminator is used to communicate information about the scan to the distant receiver so it can recreate the image with the collected scattered light. This NLOS/bistatic configuration also enables one to view an underwater target through the air-sea interface (transmitter below the surface and receiver above the surface) without the distortions experienced with the LOS/monostatic sensor. In this paper, we will review the results of recent laboratory water tank experiments where an underwater object was imaged with the receiver both below and above the sea surface.

  9. Precision experiments in electroweak interactions

    SciTech Connect

    Swartz, M.L.

    1990-03-01

    The electroweak theory of Glashow, Weinberg, and Salam (GWS) has become one of the twin pillars upon which our understanding of all particle physics phenomena rests. It is a brilliant achievement that qualitatively and quantitatively describes all of the vast quantity of experimental data that have been accumulated over some forty years. Note that the word quantitatively must be qualified. The low energy limiting cases of the GWS theory, Quantum Electrodynamics and the V-A Theory of Weak Interactions, have withstood rigorous testing. The high energy synthesis of these ideas, the GWS theory, has not yet been subjected to comparably precise scrutiny. The recent operation of a new generation of proton-antiproton (p{bar p}) and electron-positron (e{sup +}e{sup {minus}}) colliders has made it possible to produce and study large samples of the electroweak gauge bosons W{sup {plus minus}} and Z{sup 0}. We expect that these facilities will enable very precise tests of the GWS theory to be performed in the near future. In keeping with the theme of this Institute, Physics at the 100 GeV Mass Scale, these lectures will explore the current status and the near-future prospects of these experiments.

  10. Infrared propagation in the air-sea boundary layer

    NASA Astrophysics Data System (ADS)

    Larsen, R.; Preedy, K. A.; Drake, G.

    1990-03-01

    Over the oceans and other large bodies of water the structure of the lowest layers of the atmosphere is often strongly modified by evaporation of water vapor from the water surface. At radio wavelengths this layer will usually be strongly refracting or ducting, and the layer is commonly known as the evaporation duct. However, the refractive index of air at infrared wavelengths differs from that at radio wavelengths, and the effects of the marine boundary layer on the propagation of infrared radiation are examined. Meteorological models of the air-sea boundary layer are used to compute vertical profiles of temperature and water-vapor pressure. From these are derived profiles of atmospheric refractive index at radio wavelengths and at infrared wavelengths in the window regions of low absorption. For duct propagation to occur it is necessary that the refractivity of air decreases rapidly with increasing height above the surface. At radio wavelengths this usually occurs when there is a strong lapse of water vapor pressure with increasing height. By contrast, at infrared wavelengths the refractive index is almost independent of water vapor pressure, and it is found that an infrared duct is formed only when there is a temperature inversion.

  11. Improvement of the GEOS-5 AGCM upon Updating the Air-Sea Roughness Parameterization

    NASA Technical Reports Server (NTRS)

    Garfinkel, C. I.; Molod, A.; Oman, L. D.; Song, I.-S.

    2011-01-01

    The impact of an air-sea roughness parameterization over the ocean that more closely matches recent observations of air-sea exchange is examined in the NASA Goddard Earth Observing System, version 5 (GEOS-5) atmospheric general circulation model. Surface wind biases in the GEOS-5 AGCM are decreased by up to 1.2m/s. The new parameterization also has implications aloft as improvements extend into the stratosphere. Many other GCMs (both for operational weather forecasting and climate) use a similar class of parameterization for their air-sea roughness scheme. We therefore expect that results from GEOS-5 are relevant to other models as well.

  12. Interactive Screen Experiments with Single Photons

    ERIC Educational Resources Information Center

    Bronner, Patrick; Strunz, Andreas; Silberhorn, Christine; Meyn, Jan-Peter

    2009-01-01

    Single photons are used for fundamental quantum physics experiments as well as for applications. Originally being a topic of advance courses, such experiments are increasingly a subject of undergraduate courses. We provide interactive screen experiments (ISE) for supporting the work in a real laboratory, and for students who do not have access to…

  13. Distribution and air-sea fluxes of carbon dioxide on the Chukchi Sea shelf

    NASA Astrophysics Data System (ADS)

    Pipko, I. I.; Pugach, S. P.; Repina, I. A.; Dudarev, O. V.; Charkin, A. N.; Semiletov, I. P.

    2015-12-01

    This article presents the results of long-term studies of the dynamics of carbonate parameters and air-sea carbon dioxide fluxes on the Chukchi Sea shelf during the summer. As a result of the interaction of physical and biological factors, the surface waters on the west of Chukchi Sea were undersaturated with carbon dioxide when compared with atmospheric air; the partial pressure of CO2 varied in the range from 134 to 359 μatm. The average value of CO2 flux in the Chukchi Sea per unit area varied in the range from-2.4 to-22.0 mmol /(m2 day), which is significantly higher than the average value of CO2 flux in the World Ocean. It has been estimated that the minimal mass of C absorbed by the surface of Chukchi Sea from the atmosphere during ice-free season is 13 × 1012 g; a great part of this carbon is transported to the deeper layers of sea and isolated from the atmosphere for a long period of time. The studies of the carbonate system of the Chukchi Sea, especially of its western part, will provide some new data on the fluxes of carbon dioxide in the Arctic Ocean and their changes. Our analysis can be used for an interpretation of the satellite assessment of CO2 fluxes and dissolved CO2 distribution in the upper layers of the ocean.

  14. The air-sea interface and surface stress under tropical cyclones.

    PubMed

    Soloviev, Alexander V; Lukas, Roger; Donelan, Mark A; Haus, Brian K; Ginis, Isaac

    2014-01-01

    Tropical cyclone track prediction is steadily improving, while storm intensity prediction has seen little progress in the last quarter century. Important physics are not yet well understood and implemented in tropical cyclone forecast models. Missing and unresolved physics, especially at the air-sea interface, are among the factors limiting storm predictions. In a laboratory experiment and coordinated numerical simulation, conducted in this work, the microstructure of the air-water interface under hurricane force wind resembled Kelvin-Helmholtz shear instability between fluids with a large density difference. Supported by these observations, we bring forth the concept that the resulting two-phase environment suppresses short gravity-capillary waves and alters the aerodynamic properties of the sea surface. The unified wave-form and two-phase parameterization model shows the well-known increase of the drag coefficient (Cd) with wind speed, up to ~30 ms(-1). Around 60 ms(-1), the new parameterization predicts a local peak of Ck/Cd, under constant enthalpy exchange coefficient Ck. This peak may explain rapid intensification of some storms to major tropical cyclones and the previously reported local peak of lifetime maximum intensity (bimodal distribution) in the best-track records. The bimodal distribution of maximum lifetime intensity, however, can also be explained by environmental parameters of tropical cyclones alone. PMID:24930493

  15. Tuning a physically-based model of the air-sea gas transfer velocity

    NASA Astrophysics Data System (ADS)

    Jeffery, C. D.; Robinson, I. S.; Woolf, D. K.

    Air-sea gas transfer velocities are estimated for one year using a 1-D upper-ocean model (GOTM) and a modified version of the NOAA-COARE transfer velocity parameterization. Tuning parameters are evaluated with the aim of bringing the physically based NOAA-COARE parameterization in line with current estimates, based on simple wind-speed dependent models derived from bomb-radiocarbon inventories and deliberate tracer release experiments. We suggest that A = 1.3 and B = 1.0, for the sub-layer scaling parameter and the bubble mediated exchange, respectively, are consistent with the global average CO 2 transfer velocity k. Using these parameters and a simple 2nd order polynomial approximation, with respect to wind speed, we estimate a global annual average k for CO 2 of 16.4 ± 5.6 cm h -1 when using global mean winds of 6.89 m s -1 from the NCEP/NCAR Reanalysis 1 1954-2000. The tuned model can be used to predict the transfer velocity of any gas, with appropriate treatment of the dependence on molecular properties including the strong solubility dependence of bubble-mediated transfer. For example, an initial estimate of the global average transfer velocity of DMS (a relatively soluble gas) is only 11.9 cm h -1 whilst for less soluble methane the estimate is 18.0 cm h -1.

  16. The air-sea interface and surface stress under tropical cyclones

    NASA Astrophysics Data System (ADS)

    Soloviev, Alexander V.; Lukas, Roger; Donelan, Mark A.; Haus, Brian K.; Ginis, Isaac

    2014-06-01

    Tropical cyclone track prediction is steadily improving, while storm intensity prediction has seen little progress in the last quarter century. Important physics are not yet well understood and implemented in tropical cyclone forecast models. Missing and unresolved physics, especially at the air-sea interface, are among the factors limiting storm predictions. In a laboratory experiment and coordinated numerical simulation, conducted in this work, the microstructure of the air-water interface under hurricane force wind resembled Kelvin-Helmholtz shear instability between fluids with a large density difference. Supported by these observations, we bring forth the concept that the resulting two-phase environment suppresses short gravity-capillary waves and alters the aerodynamic properties of the sea surface. The unified wave-form and two-phase parameterization model shows the well-known increase of the drag coefficient (Cd) with wind speed, up to ~30 ms-1. Around 60 ms-1, the new parameterization predicts a local peak of Ck/Cd, under constant enthalpy exchange coefficient Ck. This peak may explain rapid intensification of some storms to major tropical cyclones and the previously reported local peak of lifetime maximum intensity (bimodal distribution) in the best-track records. The bimodal distribution of maximum lifetime intensity, however, can also be explained by environmental parameters of tropical cyclones alone.

  17. The air-sea interface and surface stress under tropical cyclones

    PubMed Central

    Soloviev, Alexander V.; Lukas, Roger; Donelan, Mark A.; Haus, Brian K.; Ginis, Isaac

    2014-01-01

    Tropical cyclone track prediction is steadily improving, while storm intensity prediction has seen little progress in the last quarter century. Important physics are not yet well understood and implemented in tropical cyclone forecast models. Missing and unresolved physics, especially at the air-sea interface, are among the factors limiting storm predictions. In a laboratory experiment and coordinated numerical simulation, conducted in this work, the microstructure of the air-water interface under hurricane force wind resembled Kelvin-Helmholtz shear instability between fluids with a large density difference. Supported by these observations, we bring forth the concept that the resulting two-phase environment suppresses short gravity-capillary waves and alters the aerodynamic properties of the sea surface. The unified wave-form and two-phase parameterization model shows the well-known increase of the drag coefficient (Cd) with wind speed, up to ~30 ms−1. Around 60 ms−1, the new parameterization predicts a local peak of Ck/Cd, under constant enthalpy exchange coefficient Ck. This peak may explain rapid intensification of some storms to major tropical cyclones and the previously reported local peak of lifetime maximum intensity (bimodal distribution) in the best-track records. The bimodal distribution of maximum lifetime intensity, however, can also be explained by environmental parameters of tropical cyclones alone. PMID:24930493

  18. Quantifying air-sea gas exchange using noble gases in a coastal upwelling zone

    NASA Astrophysics Data System (ADS)

    Manning, C. C.; Stanley, R. H. R.; Nicholson, D. P.; Squibb, M. E.

    2016-05-01

    The diffusive and bubble-mediated components of air-sea gas exchange can be quantified separately using time-series measurements of a suite of dissolved inert gases. We have evaluated the performance of four published air-sea gas exchange parameterizations using a five-day time-series of dissolved He, Ne, Ar, Kr, and Xe concentration in Monterey Bay, CA. We constructed a vertical model including surface air-sea gas exchange and vertical diffusion. Diffusivity was measured throughout the cruise from profiles of turbulent microstructure. We corrected the mixed layer gas concentrations for an upwelling event that occurred partway through the cruise. All tested parameterizations gave similar results for Ar, Kr, and Xe; their air-sea fluxes were dominated by diffusive gas exchange during our study. For He and Ne, which are less soluble, and therefore more sensitive to differences in the treatment of bubble-mediated exchange, the parameterizations gave widely different results with respect to the net gas exchange flux and the bubble flux. This study demonstrates the value of using a suite of inert gases, especially the lower solubility ones, to parameterize air-sea gas exchange.

  19. Experiences with Interactive Multi-touch Tables

    NASA Astrophysics Data System (ADS)

    Fikkert, Wim; Hakvoort, Michiel; van der Vet, Paul; Nijholt, Anton

    Interactive multi-touch tables can be a powerful means of communication for collaborative work as well as an engaging environment for competition. Through enticing gameplay we have evaluated user experience on competitive gameplay, collaborative work and musical expression. In addition, we report on our extensive experiences with two types of interactive multi-touch tables and we introduce a software framework that abstracts from their technical differences.

  20. Solar Array Module Plasma Interaction Experiment (SAMPIE)

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    1992-01-01

    The objective of the Solar Array Module Plasma Interaction Experiment (SAMPIE) is to investigate, by means of a shuttle-based flight experiment and relevant ground-based testing, the arcing and current collection behavior of materials and geometries likely to be exposed to the LEO plasma on high-voltage space power systems, in order to minimize adverse environmental interactions. An overview of the SAMPIE program is presented in outline and graphical form.

  1. Design for Engaging Experience and Social Interaction

    ERIC Educational Resources Information Center

    Harteveld, Casper; ten Thij, Eleonore; Copier, Marinka

    2011-01-01

    One of the goals of game designers is to design for an engaging experience and for social interaction. The question is how. We know that games can be engaging and allow for social interaction, but how do we achieve this or even improve on it? This article provides an overview of several scientific approaches that deal with this question. It…

  2. CLIVAR-GSOP/GODAE Ocean Synthesis Inter-Comparison of Global Air-Sea Fluxes From Ocean and Coupled Reanalyses

    NASA Astrophysics Data System (ADS)

    Valdivieso, Maria

    2014-05-01

    .I. and E.C. Kent (2009), A New Air-Sea Interaction Gridded Dataset from ICOADS with Uncertainty Estimates. Bull. Amer. Meteor. Soc 90(5), 645-656. doi: 10.1175/2008BAMS2639.1. Dee, D. P. et al. (2011), The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q.J.R. Meteorol. Soc., 137: 553-597. doi: 10.1002/qj.828. Kanamitsu M., Ebitsuzaki W., Woolen J., Yang S.K., Hnilo J.J., Fiorino M., Potter G. (2002), NCEP-DOE AMIP-II reanalysis (R-2). Bull. Amer. Meteor. Soc., 83:1631-1643. Large, W. and Yeager, S. (2009), The global climatology of an interannually varying air-sea flux data set. Clim. Dynamics, Volume 33, pp 341-364 Valdivieso, M. and co-authors (2014): Heat fluxes from ocean and coupled reanalyses, Clivar Exchanges. Issue 64. Yu, L., X. Jin, and R. A. Weller (2008), Multidecade Global Flux Datasets from the Objectively Analyzed Air-sea Fluxes (OAFlux) Project: Latent and Sensible Heat Fluxes, Ocean Evaporation, and Related Surface Meteorological Variables. Technical Report OAFlux Project (OA2008-01), Woods Hole Oceanographic Institution. Zhang, Y., WB Rossow, AA Lacis, V Oinas, MI Mishchenk (2004), Calculation of radiative fluxes from the surface to top of atmsophere based on ISCCP and other global data sets. Journal of Geophysical Research: Atmospheres (1984-2012) 109 (D19).

  3. Climate simulations with a new air-sea turbulent flux parameterization in the National Center for Atmospheric Research Community Atmosphere Model (CAM3)

    NASA Astrophysics Data System (ADS)

    Ban, Junmei; Gao, Zhiqiu; Lenschow, Donald H.

    2010-01-01

    This study examines climate simulations with the National Center for Atmospheric Research Community Atmosphere Model version 3 (NCAR CAM3) using a new air-sea turbulent flux parameterization scheme. The current air-sea turbulent flux scheme in CAM3 consists of three basic bulk flux equations that are solved simultaneously by an iterative computational technique. We recently developed a new turbulent flux parameterization scheme where the Obukhov stability length is parameterized directly by using a bulk Richardson number, an aerodynamic roughness length, and a heat roughness length. Its advantages are that it (1) avoids the iterative process and thus increases the computational efficiency, (2) takes account of the difference between z0m and z0h and allows large z0m/z0h, and (3) preserves the accuracy of iteration. An offline test using Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) data shows that the original scheme overestimates the surface fluxes under very weak winds but the new scheme gives better results. Under identical initial and boundary conditions, the original CAM3 and CAM3 coupled with the new turbulent flux scheme are used to simulate the global distribution of air-sea surface turbulent fluxes, and precipitation. Comparisons of model outputs against the European Remote Sensing Satellites (ERS), the Objectively Analyzed air-sea Fluxes (OAFlux), and Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) show that: (1) the new scheme produces more realistic surface wind stress in the North Pacific and North Atlantic trade wind belts and wintertime extratropical storm track regions; (2) the latent heat flux in the Northern Hemisphere trade wind zones shows modest improvement in the new scheme, and the latent heat flux bias in the western boundary current region of the Gulf Stream is reduced; and (3) the simulated precipitation in the new scheme is closer to observation in the Asian monsoon

  4. An overview of sea state conditions and air-sea fluxes during RaDyO

    NASA Astrophysics Data System (ADS)

    Zappa, Christopher J.; Banner, Michael L.; Schultz, Howard; Gemmrich, Johannes R.; Morison, Russel P.; Lebel, Deborah A.; Dickey, Tommy

    2012-07-01

    Refining radiative-transfer modeling capabilities for light transmission through the sea surface requires a more detailed prescription of the sea surface roughness beyond the probability density function of the sea surface slope field. To meet this need, exciting new measurement methodologies now provide the opportunity to enhance present knowledge of sea surface roughness, especially at the microscale. In this context, two intensive field experiments using R/PFloating Instrument Platformwere staged within the Office of Naval Research's Radiance in a Dynamic Ocean (RaDyO) field program in the Santa Barbara Channel and in the central Pacific Ocean south of Hawaii. As part of this program, our team gathered and analyzed a comprehensive suite of sea surface roughness measurements designed to provide optimal coverage of fundamental optical distortion processes associated with the air-sea interface. This contribution describes the ensemble of instrumentation deployed. It provides a detailed documentation of the ambient environmental conditions that prevailed during the RaDyO field experiments. It also highlights exciting new sea surface roughness measurement capabilities that underpin a number of the scientific advances resulting from the RaDyO program. For instance, a new polarimetric imaging camera highlights the complex interplay of wind and surface currents in shaping the roughness of the sea surface that suggests the traditional Cox-Munk framework is not sufficient. In addition, the breaking crest length spectral density derived from visible and infrared imagery is shown to be modulated by the development of the wavefield (wave age) and alignment of wind and surface currents at the intermediate (dominant) scale of wave breaking.

  5. Relationships Between the Bulk-Skin Sea Surface Temperature Difference, Wind, and Net Air-Sea Heat Flux

    NASA Technical Reports Server (NTRS)

    Emery, William J.; Castro, Sandra L.; Lindstrom, Eric (Technical Monitor)

    2002-01-01

    The primary purpose of this project was to evaluate and improve models for the bulk-skin temperature difference to the point where they could accurately and reliably apply under a wide variety of environmental conditions. To accomplish this goal, work was conducted in three primary areas. These included production of an archive of available data sets containing measurements of the skin and bulk temperatures and associated environmental conditions, evaluation of existing skin layer models using the compiled data archive, and additional theoretical work on the development of an improved model using the data collected under diverse environmental conditions. In this work we set the basis for a new physical model of renewal type, and propose a parameterization for the temperature difference across the cool skin of the ocean in which the effects of thermal buoyancy, wind stress, and microscale breaking are all integrated by means of the appropriate renewal time scales. Ideally, we seek to obtain a model that will accurately apply under a wide variety of environmental conditions. A summary of the work in each of these areas is included in this report. A large amount of work was accomplished under the support of this grant. The grant supported the graduate studies of Sandra Castro and the preparation of her thesis which will be completed later this year. This work led to poster presentations at the 1999 American Geophysical Union Fall Meeting and 2000 IGARSS meeting. Additional work will be presented in a talk at this year's American Meteorological Society Air-Sea Interaction Meeting this May. The grant also supported Sandra Castro during a two week experiment aboard the R/P Flip (led by Dr. Andrew Jessup of the Applied Physics Laboratory) to help obtain additional shared data sets and to provide Sandra with a fundamental understanding of the physical processes needed in the models. In a related area, the funding also partially supported Dr. William Emery and Daniel

  6. Affective loop experiences: designing for interactional embodiment

    PubMed Central

    Höök, Kristina

    2009-01-01

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves—the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for ‘open’ surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a ‘unity’ of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and

  7. Affective loop experiences: designing for interactional embodiment.

    PubMed

    Höök, Kristina

    2009-12-12

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves-the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for 'open' surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a 'unity' of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and experienced

  8. An experiment with interactive planning models

    NASA Technical Reports Server (NTRS)

    Beville, J.; Wagner, J. H.; Zannetos, Z. S.

    1970-01-01

    Experiments on decision making in planning problems are described. Executives were tested in dealing with capital investments and competitive pricing decisions under conditions of uncertainty. A software package, the interactive risk analysis model system, was developed, and two controlled experiments were conducted. It is concluded that planning models can aid management, and predicted uses of the models are as a central tool, as an educational tool, to improve consistency in decision making, to improve communications, and as a tool for consensus decision making.

  9. Interactive Video Networks: Experiences, Issues and Challenges.

    ERIC Educational Resources Information Center

    Stahl, Bil

    1993-01-01

    Discusses multipoint interactive video networks and describes experiences with two networks in North Carolina, the MCNC CONCERT (COmmunications network of North Carolina for Education, Research, and Technology) and the Vision Carolina network. Digital video is explained, and issues concerning various components of the telecommunications industry…

  10. Young Children as Explorers: Interactive Learning Experiences

    ERIC Educational Resources Information Center

    Center for Best Practices in Early Childhood Education, 2004

    2004-01-01

    This curriculum, designed for young children ages 3-6, focuses on math, science, and social studies and includes integrated activities to use with over 30 software titles. Young Children as Explorers: Interactive Learning Experiences addresses learning standards established by the National Council for Teachers of Mathematics, National Research…

  11. Plasma Interaction Experiment (PIX) flight results

    NASA Technical Reports Server (NTRS)

    Grier, N. T.; Stevens, N. J.

    1979-01-01

    An auxiliary payload package called PIX (plasma interaction experiment) was launched on March 5, 1978, on the LANDSAT 3 launch vehicle to study interactions between the space charged-particle environment and surfaces at high applied positive and negative voltages. Three experimental surfaces were used in this package: a plain disk to act as a control, a disk on a Kapton sheet to determine the effect of surrounding insulation on current collection, and a small solar-array segment to evaluate the effect of distributing biased surfaces among an array of insulators. Only half of the results from the 4 hours of PIX operations were recovered. The results did verify effects found in ground simulation testing. The results of this experiment are discussed in detail.

  12. Mueller matrix imaging of targets under an air-sea interface.

    PubMed

    Zhai, Peng-Wang; Kattawar, George W; Yang, Ping

    2009-01-10

    The Mueller matrix imaging method is a powerful tool for target detection. In this study, the effect of the air-sea interface on the detection of underwater objects is studied. A backward Monte Carlo code has been developed to study this effect. The main result is that the reflection of the diffuse sky light by the interface reduces the Mueller image contrast. If the air-sea interface is ruffled by wind, the distinction between different regions of the underwater target is smoothed out. The effect of the finite size of an active light source is also studied. The image contrast is found to be relatively insensitive to the size of the light source. The volume scattering function plays an important role on the underwater object detection. Generally, a smaller asymmetry parameter decreases the contrast of the polarimetry images. PMID:19137035

  13. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts

    NASA Astrophysics Data System (ADS)

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-07-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change.

  14. Small Autonomous Air/Sea System Concepts for Coast Guard Missions

    NASA Technical Reports Server (NTRS)

    Young, Larry A.

    2005-01-01

    A number of small autonomous air/sea system concepts are outlined in this paper that support and enhance U.S. Coast Guard missions. These concepts draw significantly upon technology investments made by NASA in the area of uninhabited aerial vehicles and robotic/intelligent systems. Such concepts should be considered notional elements of a greater as-yet-not-defined robotic system-of-systems designed to enable unparalleled maritime safety and security.

  15. Climatic Impacts of a Stochastic Parameterization of Air-Sea Fluxes

    NASA Astrophysics Data System (ADS)

    Williams, P. D.

    2014-12-01

    The atmosphere and ocean are coupled by the exchange of fluxes across the ocean surface. Air-sea fluxes vary partly on scales that are too small and fast to be resolved explicitly in numerical models of weather and climate, making them a candidate for stochastic parameterization. This presentation proposes a nonlinear physical mechanism by which stochastic fluctuations in the air-sea buoyancy flux may modify the mean climate, even though the mean fluctuation is zero. The mechanism relies on a fundamental asymmetry in the physics of the ocean mixed layer: positive surface buoyancy fluctuations cannot undo the vertical mixing caused by negative fluctuations. The mechanism has much in common with Stommel's mixed-layer demon. The presentation demonstrates the mechanism in climate simulations with a comprehensive coupled atmosphere-ocean general circulation model (SINTEX-G). In the SINTEX-G simulations with stochastic air-sea buoyancy fluxes, significant changes are detected in the time-mean oceanic mixed-layer depth, sea-surface temperature, atmospheric Hadley circulation, and net upward water flux at the sea surface. Also, El Niño Southern Oscillation (ENSO) variability is significantly increased. The findings demonstrate that noise-induced drift and noise-enhanced variability, which are familiar concepts from simple climate models, continue to apply in comprehensive climate models with millions of degrees of freedom. The findings also suggest that the lack of representation of sub-grid variability in air-sea fluxes may contribute to some of the biases exhibited by contemporary climate models.

  16. Temporal variability of air-sea CO2 exchange in a low-emission estuary

    NASA Astrophysics Data System (ADS)

    Mørk, Eva Thorborg; Sejr, Mikael Kristian; Stæhr, Peter Anton; Sørensen, Lise Lotte

    2016-07-01

    There is the need for further study of whether global estimates of air-sea CO2 exchange in estuarine systems capture the relevant temporal variability and, as such, the temporal variability of bulk parameterized and directly measured CO2 fluxes was investigated in the Danish estuary, Roskilde Fjord. The air-sea CO2 fluxes showed large temporal variability across seasons and between days and that more than 30% of the net CO2 emission in 2013 was a result of two large fall and winter storms. The diurnal variability of ΔpCO2 was up to 400 during summer changing the estuary from a source to a sink of CO2 within the day. Across seasons the system was suggested to change from a sink of atmospheric CO2 during spring to near neutral during summer and later to a source of atmospheric CO2 during fall. Results indicated that Roskilde Fjord was an annual low-emission estuary, with an estimated bulk parameterized release of 3.9 ± 8.7 mol CO2 m-2 y-1 during 2012-2013. It was suggested that the production-respiration balance leading to the low annual emission in Roskilde Fjord, was caused by the shallow depth, long residence time and high water quality in the estuary. In the data analysis the eddy covariance CO2 flux samples were filtered according to the H2Osbnd CO2 cross-sensitivity assessment suggested by Landwehr et al. (2014). This filtering reduced episodes of contradicting directions between measured and bulk parameterized air-sea CO2 exchanges and changed the net air-sea CO2 exchange from an uptake to a release. The CO2 gas transfer velocity was calculated from directly measured CO2 fluxes and ΔpCO2 and agreed to previous observations and parameterizations.

  17. Direct measurements of air-sea CO2 exchange over a coral reef

    NASA Astrophysics Data System (ADS)

    McGowan, Hamish A.; MacKellar, Mellissa C.; Gray, Michael A.

    2016-05-01

    Quantification of CO2 exchange with the atmosphere over coral reefs has relied on microscale measurements of pCO2 gradients across the air-sea interfacial boundary; shipboard measurements of air-sea CO2 exchange over adjacent ocean inferred to represent over reef processes or ecosystem productivity modeling. Here we present by way of case study the first direct measurements of air-sea CO2 exchange over a coral reef made using the eddy covariance method. Research was conducted during the summer monsoon over a lagoonal platform reef in the southern Great Barrier Reef, Australia. Results show the reef flat to be a net source of CO2 to the atmosphere of similar magnitude as coastal lakes, while adjacent shallow and deep lagoons were net sinks as was the surrounding ocean. This heterogeneity in CO2 exchange with the atmosphere confirms need for spatially representative direct measurements of CO2 over coral reefs to accurately quantify their role in atmospheric carbon budgets.

  18. Linking air-sea energy exchanges and European anchovy potential spawning ground

    NASA Astrophysics Data System (ADS)

    Grammauta, R.; Molteni, D.; Basilone, G.; Guisande, C.; Bonanno, A.; Aronica, S.; Giacalone, G.; Fontana, I.; Zora, M.; Patti, B.; Cuttitta, A.; Buscaino, G.; Sorgente, R.; Mazzola, S.

    2008-10-01

    The physical and chemical processes of the sea greatly affect the reproductive biology of fishes, mainly influencing both the numbers of spawned eggs and the survivorship of early stages up to the recruitment period. In the central Mediterranean, the European anchovy constitutes one of the most important fishery resource. Because of its short living nature and of its recruitment variability, associated to high environmental variability, this small pelagic species undergo high interannual fluctuation in the biomass levels. Despite several efforts were addressed to characterize fishes spawning habitat from the oceanographic point of view, very few studies analyze the air-sea exchanges effects. To characterize the spawning habitat of these resources a specific technique (quotient rule analysis) was applied on air-sea heat fluxes, wind stress, sea surface temperature and turbulence data, collected in three oceanographic surveys during the summer period of 2004, 2005 and 2006. The results showed the existence of preferred values in the examined physical variables, associated to anchovy spawning areas. Namely, for heat fluxes the values were around -40 W/m2, for wind stress 0.04-0.11 N/m2, for SST 23°C, and 300 - 500 m3s-3 for wind mixing. Despite the obtained results are preliminary, this is the first relevant analysis on the air-sea exchanges and their relationship with the fish biology of pelagic species.

  19. Development of an Eddy Covariance System for Air-Sea Carbon Dioxide Exchange

    NASA Astrophysics Data System (ADS)

    Miller, S. D.; Marandino, C. A.; McCormick, C.; Saltzman, E. S.

    2006-12-01

    We are developing a ship-based system to measure the air-sea pCO2 gradient and air-sea turbulent flux of CO2 over the ocean. The eddy covariance flux system uses off-the-shelf instruments to measure the turbulent wind vector (Campbell Scientific CSAT3 sonic anemometer), platform motion (Systron Donner Motion Pak II), and carbon dioxide molar density (LiCor 7000 Infrared Gas Analyzer). Two major sources of uncertainty in calculated fluxes are the effect of water vapor fluctuations on air density fluctuations (the WPL effect, Webb, Pearman and Leuning. 1980), and a spurious CO2 signal due to the sensitivity of the gas analyzer to platform motion (McGillis et al., 1998). Two flux systems were deployed side-by-side on a cruise from Manzanillo, Mexico to Puntas Arenas, Chile, in January 2006. Results from the cruise are presented, with a focus on our attempts to reduce biases in the calculated air-sea CO2 flux due to the WPL effect and the motion sensitivity of the gas analyzer.

  20. A reconciliation of empirical and mechanistic models of the air-sea gas transfer velocity

    NASA Astrophysics Data System (ADS)

    Goddijn-Murphy, Lonneke; Woolf, David K.; Callaghan, Adrian H.; Nightingale, Philip D.; Shutler, Jamie D.

    2016-01-01

    Models of the air-sea transfer velocity of gases may be either empirical or mechanistic. Extrapolations of empirical models to an unmeasured gas or to another water temperature can be erroneous if the basis of that extrapolation is flawed. This issue is readily demonstrated for the most well-known empirical gas transfer velocity models where the influence of bubble-mediated transfer, which can vary between gases, is not explicitly accounted for. Mechanistic models are hindered by an incomplete knowledge of the mechanisms of air-sea gas transfer. We describe a hybrid model that incorporates a simple mechanistic view—strictly enforcing a distinction between direct and bubble-mediated transfer—but also uses parameterizations based on data from eddy flux measurements of dimethyl sulphide (DMS) to calibrate the model together with dual tracer results to evaluate the model. This model underpins simple algorithms that can be easily applied within schemes to calculate local, regional, or global air-sea fluxes of gases.

  1. Measuring important parameters for air-sea heat exchange

    NASA Astrophysics Data System (ADS)

    Garbe, Christoph; Schimpf, Uwe; Jaehne, Bernd

    2002-03-01

    The heat transfer between the ocean and the atmosphere is one of the most important parameters governing the global climate. Important parameters include the heat transfer velocity and the net heat flux as well as parameters of the underlying transport model. However, the net heat flux is hard to measure since processes take place in the thermal boundary layer, that is the topmost layer of the ocean less than 1 mm thick. Current techniques rely on three independent measurements of the constituent fluxes, the sensible heat flux, latent heat flux and radiative flux. They depend on indirect measurements of meteorological parameters and rely on a combination of data from different sensors using a number of heuristic assumptions. High relative errors and the need for long temporal averaging reduce the practicability of these techniques. In this paper a novel technique is presented that circumvents these drawbacks by directly measuring the net heat flux across the air-water interface with a single low-NETD infrared camera. A newly developed digital image processing technique allows to simultaneously estimating the surface velocity field and parameters of the temporal temperature change. In particular, this technique allows estimating the total derivative of the temperature with respect to time from a sequence of infrared images, together with error bounds on the estimates. This derivative can be used to compute the heat flux density and the heat transfer velocity, as well as the probability density function of the underlying surface renewal model. It is also possible to estimate the bulk-skin temperature difference given rise to by the net heat flux. Our technique has been successfully used in both laboratory measurements in the Heidelberg Aeolotron, as well as in field measurements in the equatorial pacific during the NOAA GasExII experiment this spring. The data show that heat flux measurements to an accuracy of better than 5% on a time scale of seconds are feasible.

  2. Air-sea fluxes in a climate model using hourly coupling between the atmospheric and the oceanic components

    NASA Astrophysics Data System (ADS)

    Tian, Fangxing; von Storch, Jin-Song; Hertwig, Eileen

    2016-06-01

    We analyse the changes in the air-sea fluxes of momentum, heat and fresh water flux caused by increasing the ocean-atmosphere coupling frequency from once per day to once per hour in the Max Planck Institute Earth System Model. We diagnose the relative influences of daily averaging and high-frequency feedbacks on the basic statistics of the air-sea fluxes at grid point level and quantify feedback modes responsible for large scale changes in fluxes over the Southern Ocean and the Equatorial Pacific. Coupling once per hour instead of once per day reduces the mean of the momentum-flux magnitude by up to 7 % in the tropics and increases it by up to 10 % in the Southern Ocean. These changes result solely from feedbacks between atmosphere and ocean occurring on time scales shorter than 1 day . The variance and extremes of all the fluxes are increased in most parts of the oceans. Exceptions are found for the momentum and fresh water fluxes in the tropics. The increases result mainly from the daily averaging, while the decreases in the tropics are caused by the high-frequency feedbacks. The variance increases are substantial, reaching up to 50 % for the momentum flux, 100 % for the fresh water flux, and a factor of 15 for the net heat flux. These diurnal and intra-diurnal variations account for up to 50-90 % of the total variances and exhibit distinct seasonality. The high-frequency coupling can influence the large-scale feedback modes that lead to large-scale changes in the magnitude of wind stress over the Southern Ocean and Equatorial Pacific. In the Southern Ocean, the dependence of the SST-wind-stress feedback on the mean state of SST, which is colder in the experiment with hourly coupling than in the experiment with daily coupling, leads to an increase of westerlies. In the Equatorial Pacific, Bjerknes feedback in the hourly coupled experiment reveals a diurnal cycle during the El Niño events, with the feedback being stronger in the nighttime than in the daytime and

  3. Discovery & Interaction in Astro 101 Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Maloney, Frank Patrick; Maurone, Philip; DeWarf, Laurence E.

    2016-01-01

    The availability of low-cost, high-performance computing hardware and software has transformed the manner by which astronomical concepts can be re-discovered and explored in a laboratory that accompanies an astronomy course for arts students. We report on a strategy, begun in 1992, for allowing each student to understand fundamental scientific principles by interactively confronting astronomical and physical phenomena, through direct observation and by computer simulation. These experiments have evolved as :a) the quality and speed of the hardware has greatly increasedb) the corresponding hardware costs have decreasedc) the students have become computer and Internet literated) the importance of computationally and scientifically literate arts graduates in the workplace has increased.We present the current suite of laboratory experiments, and describe the nature, procedures, and goals in this two-semester laboratory for liberal arts majors at the Astro 101 university level.

  4. Biology and air-sea gas exchange controls on the distribution of carbon isotope ratios (δ13C) in the ocean

    NASA Astrophysics Data System (ADS)

    Schmittner, A.; Gruber, N.; Mix, A. C.; Key, R. M.; Tagliabue, A.; Westberry, T. K.

    2013-09-01

    Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate processes that control the distribution of δ13C of dissolved inorganic carbon (DIC) in the contemporary and preindustrial ocean. Biological fractionation and the sinking of isotopically light δ13C organic matter from the surface into the interior ocean leads to low δ13CDIC values at depths and in high latitude surface waters and high values in the upper ocean at low latitudes with maxima in the subtropics. Air-sea gas exchange has two effects. First, it acts to reduce the spatial gradients created by biology. Second, the associated temperature-dependent fractionation tends to increase (decrease) δ13CDIC values of colder (warmer) water, which generates gradients that oppose those arising from biology. Our model results suggest that both effects are similarly important in influencing surface and interior δ13CDIC distributions. However, since air-sea gas exchange is slow in the modern ocean, the biological effect dominates spatial δ13CDIC gradients both in the interior and at the surface, in contrast to conclusions from some previous studies. Calcium carbonate cycling, pH dependency of fractionation during air-sea gas exchange, and kinetic fractionation have minor effects on δ13CDIC. Accumulation of isotopically light carbon from anthropogenic fossil fuel burning has decreased the spatial variability of surface and deep δ13CDIC since the industrial revolution in our model simulations. Analysis of a new synthesis of δ13CDIC measurements from years 1990 to 2005 is used to quantify preformed and remineralized contributions as well as the effects of biology and air-sea gas exchange. The model reproduces major features of the observed large-scale distribution of δ13CDIC as well as the individual contributions and effects. Residual misfits are documented and analyzed. Simulated surface and subsurface δ13CDIC are influenced by

  5. Stand By for Fun: Experience and Interaction.

    ERIC Educational Resources Information Center

    Crockford, Douglas

    1986-01-01

    This paper explores interactivity, and considers what should be done to create a mass market for interactive media. It is suggested that one way to do so is to examine the video game phenomenon, and a model of interactivity is proposed. The model, a "home interactive theater," would involve interaction in the telling of a story, with the…

  6. Ocean Carbon Cycling and CO2 Air-Sea Exchange in Eastern Boundary Upwelling Systems

    NASA Astrophysics Data System (ADS)

    Plattner, G.; Gruber, N.; Lachkar, Z.; Frenzel, H.; Loher, D.

    2008-12-01

    Eastern boundary current (EBC) upwelling systems are regions of intense biogeochemical transformations and transports. Strong upwelling of nutrient- and carbon-rich waters tends to lead to CO2 outgassing nearshore and biologically-driven CO2 uptake offshore. Yet, the net air-sea CO2 balance of EBCs remains unknown. High near-shore productivity coupled with filaments and other meso- and submesoscale phenomena cause a substantial lateral export of organic carbon. We investigate these coastal processes in the California Current (CalCS) and the Canary Current Systems (CanCS), on the basis of the eddy-resolving, physical-biogeochemical model ROMS. Our results confirm the onshore-offshore trends in the air-sea fluxes, with substantial spatial and temporal differences due to topography, upwelling strength, and eddy activity. The CalCS is modeled to be, on average, a very small source of CO2 to the atmosphere, consistent with a recent data-based estimate by Chavez and Takahashi, while for the CanCS this is not clear yet. Regarding offshore transport, the CalCS appears to be stronger than the CanCS. Spatio-temporal variability of all carbon fluxes is substantial, particularly nearshore, posing a tremendous challenge for observing systems targeting e.g. air-sea CO2 fluxes in these dynamic regions. Further analyses of the processes that determine the mean carbon fluxes and their spatio-temporal variability will be presented. Characteristic differences and similarities between the two EBC systems will be discussed.

  7. Jet-Supercavity Interaction: Insights from Experiments

    NASA Astrophysics Data System (ADS)

    Moeny, M. J.; Krane, M. H.; Kirschner, I. N.; Kinzel, M. P.

    2015-12-01

    An experimental study was performed to evaluate some of the claims of Paryshev (2006) regarding changes to ventilated cavity behavior caused by the interaction of a jet with the cavity closure region. The experiments, conducted in the 1.22m dia. Garfield Thomas Water Tunnel, were performed for EDD to tunnel diameter of 0.022, Fr = 14.5 and 26.2. The model consisted of a converging-section nozzle mounted to the base of a 27.9mm 37° cone cavitator placed on the tunnel centerline at the end of a 138.4mm long streamlined strut. A ventilated cavity was formed over the model, then an air jet, issuing from a converging nozzle, was initiated. Changes to cavity behavior were quantified in terms of cavitation number, thrust-to- drag ratio, and stagnation pressure ratio at the jet nozzle. The results show that, while the overall trends predicted by Paryshev were observed, the data did not fully collapse, suggesting that many of the effects neglected by Paryshev's model have measureable effect.

  8. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts

    PubMed Central

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-01-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change. PMID:27435531

  9. Resolving the abundance and air-sea fluxes of airborne microorganisms in the North Atlantic Ocean

    PubMed Central

    Mayol, Eva; Jiménez, María A.; Herndl, Gerhard J.; Duarte, Carlos M.; Arrieta, Jesús M.

    2014-01-01

    Airborne transport of microbes may play a central role in microbial dispersal, the maintenance of diversity in aquatic systems and in meteorological processes such as cloud formation. Yet, there is almost no information about the abundance and fate of microbes over the oceans, which cover >70% of the Earth's surface and are the likely source and final destination of a large fraction of airborne microbes. We measured the abundance of microbes in the lower atmosphere over a transect covering 17° of latitude in the North Atlantic Ocean and derived estimates of air-sea exchange of microorganisms from meteorological data. The estimated load of microorganisms in the atmospheric boundary layer ranged between 6 × 104 and 1.6 × 107 microbes per m2 of ocean, indicating a very dynamic air-sea exchange with millions of microbes leaving and entering the ocean per m2 every day. Our results show that about 10% of the microbes detected in the boundary layer were still airborne 4 days later and that they could travel up to 11,000 km before they entered the ocean again. The size of the microbial pool hovering over the North Atlantic indicates that it could play a central role in the maintenance of microbial diversity in the surface ocean and contribute significantly to atmospheric processes. PMID:25400625

  10. Resolving the abundance and air-sea fluxes of airborne microorganisms in the North Atlantic Ocean.

    PubMed

    Mayol, Eva; Jiménez, María A; Herndl, Gerhard J; Duarte, Carlos M; Arrieta, Jesús M

    2014-01-01

    Airborne transport of microbes may play a central role in microbial dispersal, the maintenance of diversity in aquatic systems and in meteorological processes such as cloud formation. Yet, there is almost no information about the abundance and fate of microbes over the oceans, which cover >70% of the Earth's surface and are the likely source and final destination of a large fraction of airborne microbes. We measured the abundance of microbes in the lower atmosphere over a transect covering 17° of latitude in the North Atlantic Ocean and derived estimates of air-sea exchange of microorganisms from meteorological data. The estimated load of microorganisms in the atmospheric boundary layer ranged between 6 × 10(4) and 1.6 × 10(7) microbes per m(2) of ocean, indicating a very dynamic air-sea exchange with millions of microbes leaving and entering the ocean per m(2) every day. Our results show that about 10% of the microbes detected in the boundary layer were still airborne 4 days later and that they could travel up to 11,000 km before they entered the ocean again. The size of the microbial pool hovering over the North Atlantic indicates that it could play a central role in the maintenance of microbial diversity in the surface ocean and contribute significantly to atmospheric processes. PMID:25400625

  11. Biopolymers form a gelatinous microlayer at the air-sea interface when Arctic sea ice melts.

    PubMed

    Galgani, Luisa; Piontek, Judith; Engel, Anja

    2016-01-01

    The interface layer between ocean and atmosphere is only a couple of micrometers thick but plays a critical role in climate relevant processes, including the air-sea exchange of gas and heat and the emission of primary organic aerosols (POA). Recent findings suggest that low-level cloud formation above the Arctic Ocean may be linked to organic polymers produced by marine microorganisms. Sea ice harbors high amounts of polymeric substances that are produced by cells growing within the sea-ice brine. Here, we report from a research cruise to the central Arctic Ocean in 2012. Our study shows that microbial polymers accumulate at the air-sea interface when the sea ice melts. Proteinaceous compounds represented the major fraction of polymers supporting the formation of a gelatinous interface microlayer and providing a hitherto unrecognized potential source of marine POA. Our study indicates a novel link between sea ice-ocean and atmosphere that may be sensitive to climate change. PMID:27435531

  12. Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes

    NASA Technical Reports Server (NTRS)

    Durden, Stephen L.; Esteban-Fermandez, D.

    2010-01-01

    A report discusses ASAP (Air-sea Spray Airborne Profiler), a dual-wavelength radar profiler that provides measurement information about the droplet size distribution (DSD) of sea-spray, which can be used to estimate heat and moisture fluxes for hurricane research. Researchers have recently determined that sea spray can have a large effect on the magnitude and distribution of the air-sea energy flux at hurricane -force wind speeds. To obtain information about the DSD, two parameters of the DSD are required; for example, overall DSD amplitude and DSD mean diameter. This requires two measurements. Two frequencies are used, with a large enough separation that the differential frequency provides size information. One frequency is 94 GHz; the other is 220 GHz. These correspond to the Rayleigh and Mie regions. Above a surface wind speed of 10 m/ s, production of sea spray grows exponentially. Both the number of large droplets and the altitude they reach are a function of the surface wind speed.

  13. Ocean Winds and Turbulent Air-Sea Fluxes Inferred From Remote Sensing

    NASA Technical Reports Server (NTRS)

    Bourassa, Mark A.; Gille, Sarah T.; Jackson, Daren L.; Roberts, J. Brent; Wick, Gary A.

    2010-01-01

    Air-sea turbulent fluxes determine the exchange of momentum, heat, freshwater, and gas between the atmosphere and ocean. These exchange processes are critical to a broad range of research questions spanning length scales from meters to thousands of kilometers and time scales from hours to decades. Examples are discussed (section 2). The estimation of surface turbulent fluxes from satellite is challenging and fraught with considerable errors (section 3); however, recent developments in retrievals (section 3) will greatly reduce these errors. Goals for the future observing system are summarized in section 4. Surface fluxes are defined as the rate per unit area at which something (e.g., momentum, energy, moisture, or CO Z ) is transferred across the air/sea interface. Wind- and buoyancy-driven surface fluxes are called surface turbulent fluxes because the mixing and transport are due to turbulence. Examples of nonturbulent processes are radiative fluxes (e.g., solar radiation) and precipitation (Schmitt et al., 2010). Turbulent fluxes are strongly dependent on wind speed; therefore, observations of wind speed are critical for the calculation of all turbulent surface fluxes. Wind stress, the vertical transport of horizontal momentum, also depends on wind direction. Stress is very important for many ocean processes, including upper ocean currents (Dohan and Maximenko, 2010) and deep ocean currents (Lee et al., 2010). On short time scales, this horizontal transport is usually small compared to surface fluxes. For long-term processes, transport can be very important but again is usually small compared to surface fluxes.

  14. Creating Learning Experiences through Interactive Devices

    ERIC Educational Resources Information Center

    Harvey, Alexis

    2014-01-01

    In this small-scale study, the use of a simple interactive device was designed and studied ethnographically to discover how groups visiting a museum as part of a guided tour interacted with the device as viewed from the perspective of the group tour guides. As the emphasis placed on utilizing interactive devices in museums is increasing, one can…

  15. Air--Sea CO2 Cycling in the Southeastern Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Else, Brent Gordon Thomas

    During the fourth International Polar Year, an interdisciplinary study was conducted to examine the couplings between sea ice, ocean, atmosphere, and ecosystem in the southeastern Beaufort Sea. This thesis examines components of the system that control the air-sea exchange of carbon dioxide. Using eddy covariance measurements, we found enhanced CO2 exchange associated with new ice formation in winter flaw leads. This exchange was typically directed towards the surface, although we also measured one instance of outgassing. Sea surface dissolved CO2 measurements (pCO 2sw) in Amundsen Gulf showed significant undersaturation with respect to the atmosphere at freeze-up, followed by a slow increase over the winter until spring phytoplankton blooms caused strong undersaturation at break-up. Over the summer, pCO2sw increased until becoming slightly supersaturated due to surface warming. Along the southern margins of Amundsen Gulf and on the Mackenzie Shelf we found pCO2sw supersaturations in the fall due to wind-driven coastal upwelling. In the spring, this upwelling occurred along the landfast ice edges of Amundsen Gulf. By combining observations of enhanced winter gas exchange with observations of pCO 2sw in Amundsen Gulf, we derived an annual budget of air-sea CO2 exchange for the region. This exercise showed that uptake through the winter season was as important as the open water season, making the overall annual uptake of CO2 about double what had previously been calculated. Prior to this work, the prevailing paradigm of airsea CO2 cycling in Arctic polynya regions posited that strong CO2 absorption occurs in the open water seasons, and that a potential outgassing during the winter is inhibited by the sea ice cover. As a new paradigm, we propose that the spatial and temporal variability of many processes---including phytoplankton blooms, sea surface temperature and salinity changes, upwelling, river input, continental shelf processes, and the potential for high rates

  16. Air-sea exchange over Black Sea estimated from high resolution regional climate simulations

    NASA Astrophysics Data System (ADS)

    Velea, Liliana; Bojariu, Roxana; Cica, Roxana

    2013-04-01

    Black Sea is an important influencing factor for the climate of bordering countries, showing cyclogenetic activity (Trigo et al, 1999) and influencing Mediterranean cyclones passing over. As for other seas, standard observations of the atmosphere are limited in time and space and available observation-based estimations of air-sea exchange terms present quite large ranges of uncertainty. The reanalysis datasets (e.g. ERA produced by ECMWF) provide promising validation estimates of climatic characteristics against the ones in available climatic data (Schrum et al, 2001), while cannot reproduce some local features due to relatively coarse horizontal resolution. Detailed and realistic information on smaller-scale processes are foreseen to be provided by regional climate models, due to continuous improvements of physical parameterizations and numerical solutions and thus affording simulations at high spatial resolution. The aim of the study is to assess the potential of three regional climate models in reproducing known climatological characteristics of air-sea exchange over Black Sea, as well as to explore the added value of the model compared to the input (reanalysis) data. We employ results of long-term (1961-2000) simulations performed within ENSEMBLE project (http://ensemblesrt3.dmi.dk/) using models ETHZ-CLM, CNRM-ALADIN, METO-HadCM, for which the integration domain covers the whole area of interest. The analysis is performed for the entire basin for several variables entering the heat and water budget terms and available as direct output from the models, at seasonal and annual scale. A comparison with independent data (ERA-INTERIM) and findings from other studies (e.g. Schrum et al, 2001) is also presented. References: Schrum, C., Staneva, J., Stanev, E. and Ozsoy, E., 2001: Air-sea exchange in the Black Sea estimated from atmospheric analysis for the period 1979-1993, J. Marine Systems, 31, 3-19 Trigo, I. F., T. D. Davies, and G. R. Bigg (1999): Objective

  17. Tropical air-sea coupling accelerates the recovery of the Atlantic Meridional Overturning Circulation after glacial meltwater event

    NASA Astrophysics Data System (ADS)

    Krebs-Kanzow, U.; Timmermann, A.

    2009-04-01

    During "Heinrich events" brief and exceptionally large discharges of icebergs from the Laurentide and European ice sheets coincide with cold periods followed abrupt warmings. Climate reconstructions suggest that the freshwater pulses caused a temporary collapse of the Atlantic Meridional Overturning Circulation (AMOC) by stabilizing the stratification in the regions of North Atlantic Deep Water (NADW) formation. Using a coupled ocean sea-ice atmosphere model of intermediate complexity we trigger a complete shut-down of the AMOC by injection of a freshwater pulse to the northern North Atlantic. (Analyzing)The analysis of fully and partially coupled freshwater perturbation experiments under glacial conditions reveals that the reduction of northward heat transport in the North Atlantic leads to a cooling north of the thermal equator. Due to advection of cold air and an intensification of the tradewinds the Intertropical Convergence Zone (ITCZ) is shifted southward. Changes of the accumulated precipitation lead to generation of a positive salinity anomaly in the northern tropical Atlantic and a negative anomaly in the southern tropical Atlantic. During the shut-down phase of the AMOC, the cross-equatorial oceanic surface flow is halted, preventing a dilution of the positive salinity anomaly in the North Atlantic. Advected northward by the wind driven ocean circulation the positive salinity anomaly increases the upper ocean density in the deep water formation regions, thereby accelerating the recovery of the AMOC considerably. Partially coupled experiments which neglect tropical air-sea coupling reveal that the recovery time of the AMOC is almost twice as long as in the fully coupled case.

  18. Peptide-Lipid Interactions: Experiments and Applications

    PubMed Central

    Galdiero, Stefania; Falanga, Annarita; Cantisani, Marco; Vitiello, Mariateresa; Morelli, Giancarlo; Galdiero, Massimiliano

    2013-01-01

    The interactions between peptides and lipids are of fundamental importance in the functioning of numerous membrane-mediated cellular processes including antimicrobial peptide action, hormone-receptor interactions, drug bioavailability across the blood-brain barrier and viral fusion processes. Moreover, a major goal of modern biotechnology is obtaining new potent pharmaceutical agents whose biological action is dependent on the binding of peptides to lipid-bilayers. Several issues need to be addressed such as secondary structure, orientation, oligomerization and localization inside the membrane. At the same time, the structural effects which the peptides cause on the lipid bilayer are important for the interactions and need to be elucidated. The structural characterization of membrane active peptides in membranes is a harsh experimental challenge. It is in fact accepted that no single experimental technique can give a complete structural picture of the interaction, but rather a combination of different techniques is necessary. PMID:24036440

  19. Bayesian Hierarchical Air-Sea Interaction Modeling: Application to the Labrador Sea

    NASA Technical Reports Server (NTRS)

    Niiler, Pearn P.

    2002-01-01

    The objectives are to: 1) Organize data from 26 MINIMET drifters in the Labrador Sea, including sensor calibration and error checking of ARGOS transmissions. 2) Produce wind direction, barometer, and sea surface temperature time series. In addition, provide data from historical file of 150 SHARP drifters in the Labrador Sea. 3) Work with data interpretation and data-modeling assimilation issues.

  20. Imaging radar contributions to a major air-sea-ice interaction study in the Greenland Sea

    NASA Technical Reports Server (NTRS)

    Shuchman, Robert A.

    1986-01-01

    By virtue of the Synthetic Aperture Radar (SAR's) imaging capabilities, such as all-weather imaging, relatively high resolution, and large dynamic range of backscatter from SAR ice and open ocean, information on the important marginal ice zone (MIZ) parameters can be derived from the SAR data. Information on ice edge location and location of ice-edge eddies, for example, can be obtained directly from examination of the imagery as can detection of ocean fronts and internal waves. With machine-assisted manual image analysis, estimates of ice concentration, floe size distributions, and ice field motion can also be derived. Full digital analysis, however, is required to obtain gravity wave spectral information and backscatter statistics for ice type discrimination and automated ice concentration algorithms.

  1. Analysis of the inflow and air-sea interactions in Hurricane Frederic (1979)

    NASA Technical Reports Server (NTRS)

    Kaplan, J.; Frank, W. M.

    1986-01-01

    An unusually large amount of aircraft, rawinsonde, satellite, ship and buoy data from hurricane Frederic (1979) are composited over a 40 hr period. These are combined with Frank's (1984) analysis of Frederic's core and Powell's (1982) surface wind analysis to analyze Frederic's three dimensional low level structure between the storm center and a radius of 10 deg. latitude. The analysis is improved significantly by determining the levels at which low level cloud motion winds (CMW's) are in the best agreement with verification wind data and then adjusting the winds to uniform analysis levels. Due to the unusually good low level wind resolution afforded by this data set, it is possible to obtain kinematically derived fields of vorticity, divergence and vertical velocity. These analyses are observed to be internally consistent and should prove useful for future analysis. Analysis of Frederic's surface to 560 m angular momentum budget beyond 2 deg. radius indicates that surface drag coefficients increase slightly with increasing radius and decreasing wind speed. Estimates of storm rainfall obtained by performing a moisture budget between the surface and the top of the inflow layer show that most storm rainfall falls inside about 4 deg. radius and that substantial underestimation of storm rainfall occurs when all low level CMW's are assigned to 560 m.

  2. Application of the Doppler lidar system to agricultural burning and air-sea interactions

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, D.

    1980-01-01

    The Doppler lidar system is potentially a very powerful measurement system. Three areas concerning the system are discussed: (1) error analysis of the system to verify the results; (2) application of the system to agricultural burning in California central valley; and (3) oceanographic possibilities of the system.

  3. Experiments on shock/vortex interactions

    NASA Technical Reports Server (NTRS)

    Cattafesta, L. N., III; Settles, G. S.

    1992-01-01

    The interaction between a shock wave and a supersonic streamwise vortex is a fundamental fluid-dynamics problem with numerous practical applications. This paper describes an experimental study of this phenomenon. In particular, supersonic streamwise vortices of varying strength and Mach number were generated and measured using five-hole and total-temperature probes. In addition, the interactions between a vortex and either an oblique or a normal shock wave were visualized using schlieren and planar-laser-scattering techniques. The mean-flow measurements show both similarities and differences between the supersonic streamwise vortex and its incompressible counterpart, while the flow-visualization results show that the shock/vortex interaction is always unsteady and that, under certain conditions, the vortex can burst. The conditions necessary for supersonic vortex breakdown are presented.

  4. OAFlux Satellite-Based High-Resolution Analysis of Air-Sea Turbulent Heat, Moisture, and Momentum Fluxes

    NASA Astrophysics Data System (ADS)

    Yu, Lisan

    2016-04-01

    The Objectively Analyzed air-sea Fluxes (OAFlux) project at the Woods Hole Oceanographic Institution has recently developed a new suite of products: the satellite-based high-resolution (HR) air-sea turbulent heat, moisture, and momentum fluxes over the global ocean from 1987 to the present. The OAFlux-HR fluxes are computed from the COARE bulk algorithm using air-sea variables (vector wind, near-surface humidity and temperature, and ocean surface temperature) derived from multiple satellite sensors and multiple missions. The vector wind time series are merged from 14 satellite sensors, including 4 scatterometers and 10 passive microwave radiometers. The near-surface humidity and temperature time series are retrieved from 11 satellite sensors, including 7 microwave imagers and 4 microwave sounders. The endeavor has greatly improved the depiction of the air-sea turbulent exchange on the frontal and meso-scales. The OAFlux-HR turbulent flux products are valuable datasets for a broad range of studies, including the study of the long-term change and variability in the oean-surface forcing functions, quantification of the large-scale budgets of mass, heat, and freshwater, and assessing the role of the ocean in the change and variability of the Earth's climate.

  5. Peer Interaction: The Experience of Distance Students at University Level

    ERIC Educational Resources Information Center

    Ferguson, R.

    2010-01-01

    This study investigates how university students on distance learning courses experience interaction with their peers. Students on two distance learning courses at The Open University (UK) were interviewed, to investigate learners' experience of interaction on these courses. The analysis, using a grounded-theory approach, reveals disparities…

  6. Biology and air-sea gas exchange controls on the distribution of carbon isotope ratios (δ13C) in the ocean

    NASA Astrophysics Data System (ADS)

    Schmittner, A.; Gruber, N.; Mix, A. C.; Key, R. M.; Tagliabue, A.; Westberry, T. K.

    2013-05-01

    Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate the processes that control the distribution of δ13C in the contemporary and preindustrial ocean. Biological fractionation dominates the distribution of δ13CDIC of dissolved inorganic carbon (DIC) due to the sinking of isotopically light δ13C organic matter from the surface into the interior ocean. This process leads to low δ13CDIC values at dephs and in high latitude surface waters and high values in the upper ocean at low latitudes with maxima in the subtropics. Air-sea gas exchange provides an important secondary influence due to two effects. First, it acts to reduce the spatial gradients created by biology. Second, the associated temperature dependent fractionation tends to increase (decrease) δ13CDIC values of colder (warmer) water, which generates gradients that oppose those arising from biology. Our model results suggest that both effects are similarly important in influencing surface and interior δ13CDIC distributions. However, air-sea gas exchange is slow, so biological effect dominate spatial δ13CDIC gradients both in the interior and at the surface, in constrast to conclusions from some previous studies. Analysis of a new synthesis of δ13CDIC measurements from years 1990 to 2005 is used to quantify preformed (δ13Cpre) and remineralized (δ13Crem) contributions as well as the effects of biology (Δδ13Cbio) and air-sea gas exchange (δ13C*). The model reproduces major features of the observed large-scale distribution of δ13CDIC, δ13Cpre, δ13Crem, δ13C*, and Δδ13Cbio. Residual misfits are documented and analyzed. Simulated surface and subsurface δ13CDIC are influenced by details of the ecosystem model formulation. For example, inclusion of a simple parameterization of iron limitation of phytoplankton growth rates and temperature-dependent zooplankton grazing rates improves the agreement with δ13CDIC

  7. Working Smart Workbook. An Interactive Learning Experience.

    ERIC Educational Resources Information Center

    Los Angeles Unified School District, CA. Div. of Adult and Occupational Education.

    This workbook accompanies an interactive videodisc used in the Working Smart workplace literacy project prepared for the hotel and food services industry in the Los Angeles, California area. The first instructional unit addresses preparing the work area, including stocking supplies and cleaning the work area. The second instructional unit covers…

  8. Liner target interaction experiments on Pegasus II

    SciTech Connect

    Hockaday, M.P.; Chrien, R.E.; Bartsch, R.

    1995-09-01

    The Los Alamos High Energy Density Physics program uses capacitively driven low voltage, inductive-storage pulse power to implode cylindrical targets for hydrodynamics experiments. Once a precision driver liner was characterized an experimental series characterizing the aluminum target dynamics was performed. The target was developed for shock-induced quasi-particle ejecta experiments including holography. The concept for the Liner shock experiment is that the driver liner is used to impact the target liner which then accelerates toward a collimator with a slit in it. A shock wave is set up in the target liner and as the shock emerges from the back side of the target liner, ejecta are generated. By taking a laser hologram the particle distribution of the ejecta are hoped to be determined. The goal for the second experimental series was to characterize the target dynamics and not to measure and generate the ejecta. Only the results from the third shot, Pegasus II-26 fired April 26th, 1994, from the series is discussed in detail. The second experimental series successfully characterized the target dynamics necessary to move forward towards the planned quasi-ejecta experiments.

  9. Coulomb Interactions in Hanbury Brown-Twiss Experiments with Electrons

    ERIC Educational Resources Information Center

    Shen, Kan

    2009-01-01

    This dissertation examines the effect of Coulomb interactions in Hanbury Brown-Twiss (HBT) type experiments with electrons. HBT experiments deal with intensity interference, which is related to the second-order correlation function of the particle field. This is an extension of the usual amplitude interference experiment, such as Young's…

  10. Midlatitude atmosphere-ocean interaction during El Nino. Part I. The north Pacific ocean

    SciTech Connect

    Alexander, M.A. )

    1992-09-01

    Atmosphere-ocean modeling experiments are used to investigate the formation of sea surface temperature (SST) anomalies in the North Pacific Ocean during fall and winter of the El Nino year. Experiments in which the NCAR Community Climate Model (CCM) surface fields are used to force a mixed-layer ocean model in the North Pacific (no air-sea feedback) are compared to simulations in which the CCM and North Pacific Ocean model are coupled. Anomalies in the atmosphere and the North Pacific Ocean during El Nino are obtained from the difference between simulations with and without prescribed warm SST anomalies in the tropical Pacific. In both the forced and coupled experiments, the anomaly pattern resembles a composite of the actual SST anomaly field during El Nino: warm SSTs develop along the coast of North America and cold SSTs form in the central Pacific. In the coupled simulations, air-sea interaction results in a 25% to 50% reduction in the magnitude of the SST and mixed-layer depth anomalies, resulting in more realistic SST fields. Coupling also decreases the SST anomaly variance; as a result, the anomaly centers remain statistically significant even though the magnitude of the anomalies is reduced. Three additional sensitivity studies indicate that air-sea feedback and entrainment act to damp SST anomalies while Ekman pumping has a negligible effect on mixed-layer depth and SST anomalies in midatitudes.

  11. Solvent-Ion Interactions in Salt Water: A Simple Experiment.

    ERIC Educational Resources Information Center

    Willey, Joan D.

    1984-01-01

    Describes a procedurally quick, simple, and inexpensive experiment which illustrates the magnitude and some effects of solvent-ion interactions in aqueous solutions. Theoretical information, procedures, and examples of temperature, volume and hydration number calculations are provided. (JN)

  12. Oceanic distributions and air-sea fluxes of biogenic halocarbons in the open ocean

    NASA Astrophysics Data System (ADS)

    Chuck, Adele L.; Turner, Suzanne M.; Liss, Peter S.

    2005-10-01

    Surface seawater and atmospheric concentrations of methyl iodide, chloroiodomethane, bromoform, dichlorobromomethane, and chlorodibromethane were measured during three open ocean cruises in the Atlantic and Southern oceans. The measurements spanned a longitudinal range of 115°, between 50°N and 65°S. The saturation anomalies and the instantaneous air-sea fluxes of the gases during one of these cruises (ANT XVIII/1) are presented and discussed. Methyl iodide and chloroiodomethane were highly supersaturated (>1000%) throughout the temperate and tropical regions, with calculated mean fluxes of 15 and 5.5 nmol m-2 d-1, respectively. The oceanic emissions of the brominated compounds were less substantial, and a significant area of the temperate Atlantic Ocean was found to be a sink for bromoform. Correlation analyses have been used to investigate possible controls on the concentrations of these gases. In particular, the relationship of CH3I with sea surface temperature and light is discussed, with the tentative conclusion that this compound may be formed abiotically.

  13. Mississippi State University Center for Air Sea Technology FY95 Research Program

    NASA Technical Reports Server (NTRS)

    Yeske, Lanny; Corbin, James H.

    1995-01-01

    The Mississippi State University (MSU) Center for Air Sea Technology (CAST) evolved from the Institute for Naval Oceanography's (INO) Experimental Center for Mesoscale Ocean Prediction (ECMOP) which was started in 1989. MSU CAST subsequently began operation on 1 October 1992 under an Office of Naval Research (ONR) two-year grant which ended on 30 September 1994. In FY95 MSU CAST was successful in obtaining five additional research grants from ONR, as well as several other research contracts from the Naval Oceanographic Office via NASA, the Naval Research Laboratory, the Army Corps of Engineers, and private industry. In the past, MSU CAST technical research and development has produced tools, systems, techniques, and procedures that improve efficiency and overcome deficiency for both the operational and research communities residing with the Department of Defense, private industry, and university ocean modeling community. We continued this effort with the following thrust areas: to develop advanced methodologies and tools for model evaluation, validation and visualization, both oceanographic and atmospheric; to develop a system-level capability for conducting temporally and ; spatially scaled ocean simulations driven by or are responsive to ocean models, and take into consideration coupling to atmospheric models; to continue the existing oceanographic/atmospheric data management task with emphasis on distributed databases in a network environment, with database optimization and standardization, including use of Mosaic and World Wide Web (WWW) access; and to implement a high performance parallel computing technology for CAST ocean models

  14. A Unified Air-Sea Visualization System: Survey on Gridding Structures

    NASA Technical Reports Server (NTRS)

    Anand, Harsh; Moorhead, Robert

    1995-01-01

    The goal is to develop a Unified Air-Sea Visualization System (UASVS) to enable the rapid fusion of observational, archival, and model data for verification and analysis. To design and develop UASVS, modelers were polled to determine the gridding structures and visualization systems used, and their needs with respect to visual analysis. A basic UASVS requirement is to allow a modeler to explore multiple data sets within a single environment, or to interpolate multiple datasets onto one unified grid. From this survey, the UASVS should be able to visualize 3D scalar/vector fields; render isosurfaces; visualize arbitrary slices of the 3D data; visualize data defined on spectral element grids with the minimum number of interpolation stages; render contours; produce 3D vector plots and streamlines; provide unified visualization of satellite images, observations and model output overlays; display the visualization on a projection of the users choice; implement functions so the user can derive diagnostic values; animate the data to see the time-evolution; animate ocean and atmosphere at different rates; store the record of cursor movement, smooth the path, and animate a window around the moving path; repeatedly start and stop the visual time-stepping; generate VHS tape animations; work on a variety of workstations; and allow visualization across clusters of workstations and scalable high performance computer systems.

  15. Influence of precipitation on the CO2 air-sea flux, an eddy covariance field study

    NASA Astrophysics Data System (ADS)

    Zavarsky, Alexander; Steinhoff, Tobias; Marandino, Christa

    2016-04-01

    During the SPACES-OASIS cruise (July-August 2015) from Durban, SA to Male, MV direct fluxes of CO2 and dimethyl sulfide (DMS) were measured using the eddy covariance (EC) technique. The cruise covered areas of sources and sinks for atmospheric CO2, where the bulk concentration gradient measurements resembled the Takahashi (2009) climatology. Most of the time, bulk CO2 fluxes (F=k* [cwater-cair]), calculated with the parametrization (k) by Nightingale et al. 2000, were in general agreement with direct EC measurements. However, during heavy rain events, the directly measured CO2 fluxes were 4 times higher than predicted. It has been previously described that rain influences the k parametrization of air-sea gas exchange, but this alone cannot explain the measured discrepancy. There is evidence that freshwater input and a change in the carbonate chemistry causes the water side concentration of ?c=cwater-cair to decrease. Unfortunately this cannot be detected by most bulk measurement systems. Using the flux measurements of an additional gas like DMS, this rain influence can be evaluated as DMS does not react to changes in the carbonate system and has a different solubility. A pending question is if the enhanced flux of CO2 in the ocean is sequestered into the ocean mixed layer and below. This question will be tackled using the GOTM model to understand the implications for the global carbon cycle.

  16. Distinctive precursory air-sea signals between regular and super El Niños

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Li, Tim; Behera, Swadhin K.; Doi, Takeshi

    2016-08-01

    Statistically different precursory air-sea signals between a super and a regular El Niño group are investigated, using observed SST and rainfall data, and oceanic and atmospheric reanalysis data. The El Niño events during 1958-2008 are first separated into two groups: a super El Niño group (S-group) and a regular El Niño group (R-group). Composite analysis shows that a significantly larger SST anomaly (SSTA) tendency appears in S-group than in R-group during the onset phase [April-May(0)], when the positive SSTA is very small. A mixed-layer heat budget analysis indicates that the tendency difference arises primarily from the difference in zonal advective feedback and the associated zonal current anomaly ( u'). This is attributed to the difference in the thermocline depth anomaly ( D') over the off-equatorial western Pacific prior to the onset phase, as revealed by three ocean assimilation products. Such a difference in D' is caused by the difference in the wind stress curl anomaly in situ, which is mainly regulated by the anomalous SST and precipitation over the Maritime Continent and equatorial Pacific.

  17. Decline of hexachlorocyclohexane in the Arctic atmosphere and reversal of air-sea gas exchange

    NASA Astrophysics Data System (ADS)

    Bidleman, T. F.; Jantunen, L. M.; Falconer, R. L.; Barrie, L. A.; Fellin, P.

    1995-02-01

    Hexachlorocyclohexanes (HCHs) are the most abundant organochlorine pesticides in the arctic atmosphere and ocean surface water. A compilation of measurements made between 1979-93 from stations in the Canadian and Norwegian Arctic and from cruises in the Bering and Chukchi seas indicates that atmospheric concentrations of α-HCH have declined significantly (p < 0.01), with a time for 50% decrease of about 4 y in summer-fall and 6 y in winter-spring. The 1992-93 levels of about 100 pg m-3 are 2-4 fold lower than values in the mid-1980s. The trend in γ-HCH is less pronounced, but a decrease is also suggested from measurements in the Canadian Arctic and the Bering-Chukchi seas. HCHs in ocean surface water have remained relatively constant since the early 1980s. The decline in atmospheric α-HCH has reversed the net direction of air-sea gas exchange to the point where some northern waters are now sources of the pesticide to the atmosphere instead of sinks.

  18. Air-sea gas transfer for two gases of different solubility (CO2 and O2)

    NASA Astrophysics Data System (ADS)

    Rutgersson, A.; Andersson, A.; Sahlée, E.

    2016-05-01

    At the land-based marine measuring site Östergarnsholm in the Baltic Sea, the eddy covariance technique was used to measure air-sea fluxes of carbon dioxide and oxygen. High- frequency measurements of oxygen were taken with a Microx TX3 optode using the luminescence lifetime technique. The system gives reasonable oxygen fluxes after the limited frequency response of the sensor was corrected for. For fluxes of carbon dioxide the LICOR-7500 instrument was used. Using flux data to estimate transfer velocities indicates higher transfer velocity for oxygen compared to carbon dioxide for winds above 5 m/s. There are too few data for any extensive conclusions, but a least-square fit of the data gives a cubic wind speed dependence of oxygen corresponding to k 660 = 0.074U 3 10. The more effective transfer for oxygen compared to carbon dioxide above 5 m/s is most likely due to enhanced efficiency of oxygen exchange across the surface. Oxygen has lower solubility compared with carbon dioxide and might be more influenced by near surface processes such as microscale wave breaking or sea spray.

  19. Mechanisms controlling the SST air-sea heat flux feedback and its dependence on spatial scale

    NASA Astrophysics Data System (ADS)

    Hausmann, Ute; Czaja, Arnaud; Marshall, John

    2016-05-01

    The turbulent air-sea heat flux feedback (α , in {W m}^{-2}{ K}^{-1} ) is a major contributor to setting the damping timescale of sea surface temperature (SST) anomalies. In this study we compare the spatial distribution and magnitude of α in the North Atlantic and the Southern Ocean, as estimated from the ERA-Interim reanalysis dataset. The comparison is rationalized in terms of an upper bound on the heat flux feedback, associated with "fast" atmospheric export of temperature and moisture anomalies away from the marine boundary layer, and a lower bound associated with "slow" export. It is found that regions of cold surface waters (≤ 10° C) are best described as approaching the slow export limit. This conclusion is not only valid at the synoptic scale resolved by the reanalysis data, but also on basin scales. In particular, it applies to the heat flux feedback acting as circumpolar SST anomaly scales are approached in the Southern Ocean, with feedbacks of ≤ 10 {W m}^{-2}{ K}^{-1} . In contrast, the magnitude of the heat flux feedback is close to that expected from the fast export limit over the Gulf Stream and its recirculation with values on the order of ≈40 {W m}^{-2}{ K}^{-1} . Further analysis suggests that this high value reflects a compensation between a moderate thermodynamic adjustment of the boundary layer, which tends to weaken the heat flux feedback, and an enhancement of the surface winds over warm SST anomalies, which tend to enhance the feedback.

  20. Air-sea exchange of carbon dioxide in the Southern Ocean and Antarctic marginal ice zone

    NASA Astrophysics Data System (ADS)

    Butterworth, Brian J.; Miller, Scott D.

    2016-07-01

    Direct carbon dioxide flux measurements using eddy covariance from an icebreaker in the high-latitude Southern Ocean and Antarctic marginal ice zone are reported. Fluxes were combined with the measured water-air carbon dioxide partial pressure difference (ΔpCO2) to compute the air-sea gas transfer velocity (k, normalized to Schmidt number 660). The open water data showed a quadratic relationship between k (cm h-1) and the neutral 10 m wind speed (U10n, m s-1), kopen = 0.245 U10n2 + 1.3, in close agreement with decades old tracer-based results and much lower than cubic relationships inferred from previous open ocean eddy covariance studies. In the marginal ice zone, the effective gas transfer velocity decreased in proportion to sea ice cover, in contrast with predictions of enhanced gas exchange in the presence of sea ice. The combined open water and marginal ice zone results affect the calculated magnitude and spatial distribution of Southern Ocean carbon flux.

  1. Distribution and air-sea exchange of organochlorine pesticides in the North Pacific and the Arctic

    NASA Astrophysics Data System (ADS)

    Cai, Minghong; Ma, Yuxin; Xie, Zhiyong; Zhong, Guangcai; MöLler, Axel; Yang, Haizhen; Sturm, Renate; He, Jianfeng; Ebinghaus, Ralf; Meng, Xiang-Zhou

    2012-03-01

    Surface seawater and boundary layer air samples were collected on the icebreaker Xuelong (Snow Dragon) during the Fourth Chinese Arctic Research Expedition (CHINARE2010) cruise in the North Pacific and Arctic Oceans during 2010. Samples were analyzed for organochlorine pesticides (OCPs), including three isomers of hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and two isomers of heptachlor epoxide. The gaseous total HCH (ΣHCHs) concentrations were approximately four times lower (average 12.0 pg m-3) than those measured during CHINARE2008 (average 51.4 pg m-3), but were comparable to those measured during CHINARE2003 (average 13.4 pg m-3) in the same study area. These changes are consistent with the evident retreat of sea ice coverage from 2003 to 2008 and increase of sea ice coverage from 2008 to 2009 and 2010. Gaseous β-HCH concentrations in the atmosphere were typically below the method detection limit, consistent with the expectation that ocean currents provide the main transport pathway for β-HCH into the Arctic. The concentrations of all dissolved HCH isomers in seawater increase with increasing latitude, and levels of dissolved HCB also increase (from 5.7 to 7.1 pg L-1) at high latitudes (above 73°N). These results illustrate the role of cold condensation processes in the transport of OCPs. The observed air-sea gas exchange gradients in the Arctic Ocean mainly favored net deposition of OCPs, with the exception of those for β-HCH, which favored volatilization.

  2. Flow Experiences of Children in an Interactive Social Game Environment

    ERIC Educational Resources Information Center

    Inal, Yavuz; Cagiltay, Kursat

    2007-01-01

    This study examines children's flow experiences in an interactive social game environment. A total of 33 children aged from 7 to 9 years participated in the study for 6 weeks. Data were collected through observations and interviews. In order to measure the flow experiences of the children, items of a flow scale were administered to the children…

  3. Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

    NASA Astrophysics Data System (ADS)

    Bell, T. G.; De Bruyn, W.; Miller, S. D.; Ward, B.; Christensen, K.; Saltzman, E. S.

    2013-05-01

    Shipboard measurements of eddy covariance DMS air/sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s-1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air/sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near surface water side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air/sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

  4. The NEMO-AROME WMED high-resolution air-sea coupled system: impact on dense water formation

    NASA Astrophysics Data System (ADS)

    Léger, Fabien; Lebeaupin Brossier, Cindy; Giordani, Hervé; Arsouze, Thomas; Beuvier, Jonathan; Bouin, Marie-Noëlle; Ducrocq, Véronique; Fourrié, Nadia

    2016-04-01

    The North-Western Mediterranean Sea is a key location where intense air-sea exchanges occur, especially during winter when the succession of strong northerly and north-westerly wind boosts the dense water formation. The second Special Observation Period (SOP2) of the HyMeX program, which took place between 1st February and 15th March 2013, was dedicated to the observation of the dense water formation and ocean deep convection processes. During this period, several platforms sampled the area, providing a unique dataset to better identify the coupled processes leading to dense water formation. This study investigates the impacts of the fine scale ocean-atmosphere coupled processes on dense water formation during winter 2012-2013. We developed the coupling between the NEMO-WMED36 ocean model (1/36° resolution) and the AROME-WMED numerical weather prediction model (2.5 km resolution) and ran the high-resolution air-sea coupled system over SOP2. The coupled simulation is compared to an ocean-only simulation forced by AROME-WMED operational forecasts and to air-sea observations collected during the HyMeX SOP2. The results show small differences in term of surface fluxes. Dense water formation is slightly changed in the coupled simulation, whereas fine-scale ocean processes are significantly modified.

  5. Annual and seasonal fCO2 and air-sea CO2 fluxes in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Lauvset, S. K.; Chierici, M.; Counillon, F.; Omar, A.; Nondal, G.; Johannessen, T.; Olsen, A.

    2013-03-01

    The Barents Sea is the strongest CO2 sink in the Arctic region, yet estimates of the air-sea CO2 flux in this area show a large span reflecting uncertainty as well as significant variability both seasonally and regionally. Here we use a previously unpublished data set of seawater CO2 fugacity (fCO2), and map these data over the western Barents Sea through multivariable linear regressions with SeaWiFS/MODIS remote sensing and TOPAZ model data fields. We find that two algorithms are necessary in order to cover the full seasonal cycle, mainly because not all proxy variables are available for the entire year, and because variability in fCO2 is driven by different mechanisms in summer and winter. A comprehensive skill assessment indicates that there is a good overall correspondence between observations and predictions. The algorithms are also validated using two independent data sets, with good results. The gridded fCO2 fields reveal tight links between water mass distribution and fCO2 in all months, and particularly in winter. The seasonal cycle show peaks in the total air-sea CO2 influx in May and September, caused by respectively biological drawdown of CO2 and low sea ice concentration leaving a large open water area. For 2007 the annual average air-sea CO2 flux is - 48 ± 5 gC m- 2, which is comparable to previous estimates.

  6. INSPIRE - Premission. [Interactive NASA Space Physics Ionosphere Radio Experiment

    NASA Technical Reports Server (NTRS)

    Taylor, William W. L.; Mideke, Michael; Pine, William E.; Ericson, James D.

    1992-01-01

    The Interactive NASA Space Physics Ionosphere Radio Experiment (INSPIRE) designed to assist in a Space Experiments with Particle Accelerators (SEPAC) project is discussed. INSPIRE is aimed at recording data from a large number of receivers on the ground to determine the exact propagation paths and absorption of radio waves at frequencies between 50 Hz and 7 kHz. It is indicated how to participate in the experiment that will involve high school classes, colleges, and amateur radio operators.

  7. Distribution and air-sea exchange of mercury (Hg) in polluted marine environments

    NASA Astrophysics Data System (ADS)

    Bagnato, E.; Sprovieri, M.; Bitetto, M.; Bonsignore, M.; Calabrese, S.; Di Stefano, V.; Oliveri, E.; Parello, F.; Mazzola, S.

    2012-04-01

    Mercury (Hg) is emitted in the atmosphere by anthropogenic and natural sources, these last accounting for one third of the total emissions. Since the pre-industrial age, the atmospheric deposition of mercury have increased notably, while ocean emissions have doubled owing to the re-emission of anthropogenic mercury. Exchange between the atmosphere and ocean plays an important role in cycling and transport of mercury. We present the preliminary results from a study on the distribution and evasion flux of mercury at the atmosphere/sea interface in the Augusta basin (SE Sicily, southern Italy), a semi-enclosed marine area affected by a high degree of contamination (heavy metals and PHA) due to the oil refineries placed inside its commercial harbor. It seems that the intense industrial activity of the past have lead to an high Hg pollution in the bottom sediments of the basin, whose concentrations are far from the background mercury value found in most of the Sicily Strait sediments. The release of mercury into the harbor seawater and its dispersion by diffusion from sediments to the surface, make the Augusta basin a potential supplier of mercury both to the Mediterranean Sea and the atmosphere. Based on these considerations, mercury concentration and flux at the air-sea interface of the Bay have been estimated using a real-time atomic adsorption spectrometer (LUMEX - RA915+) and an home-made accumulation chamber, respectively. Estimated Total Atmospheric Mercury (TGM) concentrations during the cruise on the bay were in the range of 1-3 ng · m-3, with a mean value of about 1.4 ng · m-3. These data well fit with the background Hgatm concentration values detected on the land (1-2 ng · m-3, this work), and, more in general, with the background atmospheric TGM levels found in the North Hemisphere (1.5-1.7 ng · m-3)a. Besides, our measurements are in the range of those reported for other important polluted marine areas. The mercury evasion flux at the air-sea interface

  8. Air-Sea CO2 fluxes in the Atlantic as measured during boreal spring and autumn

    NASA Astrophysics Data System (ADS)

    Padin, X. A.; Vázquez-Rodríguez, M.; Castaño, M.; Velo, A.; Alonso-Pérez, F.; Gago, J.; Gilcoto, M.; Álvarez, M.; Pardo, P. C.; de La Paz, M.; Ríos, A. F.; Pérez, F. F.

    2010-05-01

    A total of fourteen hydrographic cruises from 2000 to 2008 were conducted during the spring and autumn seasons between Spain and the Southern Ocean under the framework of the Spanish research project FICARAM. The underway measurements were processed and analysed to describe the meridional air-sea CO2 fluxes (FCO2) in the covered sector of the Atlantic Ocean. The data has been grouped into different biogeochemical oceanographic provinces based on thermohaline characteristics. The spatial and temporal distributions of FCO2 followed expected distributions and annual trends reproducing the recent climatological ΔfCO2 estimations with a mean difference of -3 ± 18 μatm (Takahashi et al., 2009). The reduction in the CO2 saturation along the meridional FICARAM cruises represented an increase of 0.02 ± 0.14 mol m-2 yr-1 in the ocean uptake of atmospheric CO2. The subtropical waters in both Hemispheres acted as a sink of atmospheric CO2 during the successive spring seasons and as a source in autumn. The coarse reduction of the ocean uptake of atmospheric CO2 observed in the North Atlantic Ocean was linked to conditions of negative phase of the North Atlantic Oscillation that prevailed during the FICARAM period. Surface waters in the North Equatorial Counter Current revealed a significant long-term decrease of sea surface salinity of -0.16 ± 0.01 yr-1 coinciding with a declination of -3.5 ± 0.9 μatm yr-1 in the air-sea disequilibrium of CO2 fugacity and a rise of oceanic CO2 uptake of -0.09 ± 0.03 mol m-2 yr-1. The largest CO2 source was located in the equatorial upwelling system. These tropical waters that reached emissions of 0.7 ± 0.5 and 1.0 ± 0.7 mol m-2 y-1 in spring and autumn, respectively, showed an interannual warming of 0.11 ± 0.03 °C yr-1 and a wind speed decrease of -0.58 ± 0.14 m s-1 yr-1 in spring cruises which suggest the weakening of upwelling events associated with warm El Niño - Southern Oscillation episodes. Contrary the surface waters of the

  9. Air-sea Energy Transfer at Mesoscale in a Coupled High-resolution Model: Impact of Resolution and Current Feedback

    NASA Astrophysics Data System (ADS)

    Jullien, S.; Colas, F.; Masson, S. G.; Oerder, V.; Echevin, V.; Samson, G.; Crétat, J.; Berthet, S.; Hourdin, C.

    2015-12-01

    Winds are usually considered to force the ocean but recent studies suggested that oceanic mesoscale activity, characterized by eddies, filaments and fronts, could also affect the wind field. These structures feature abrupt changes in sea surface temperature (SST), surface pressure and surface currents that could impact the atmosphere by enhancing/reducing air-sea fluxes, accelerating/decelerating winds, modifying the wind-pressure balance… At this time, the detailed processes associated to such coupling, its intensity and significance remain a matter of research. Here, a state-of-the-art WRF-OASIS-NEMO coupled model is set up over a wide tropical channel (45°S-45°N) at various resolutions: 3/4°, 1/4° and 1/12° in both the ocean and the atmosphere. Several experiments are conducted in forced, partially or fully coupled modes, to highlight the effect of resolution and the role of SST vs. current feedback to energy injection into the ocean and the atmosphere. In strong mesoscale activity regions, a negative wind power input from the atmosphere to the ocean is seen at scales ranging from 100km to more than 1000km. Nonexistent at 3/4°, this negative forcing, acting against oceanic mesoscale activity, is almost twice more important at 1/12° than at 1/4°. In addition, partially coupled simulations, i.e. without current feedback, show that the impact of thermal coupling on this process is very limited. Energy injection to the marine atmospheric boundary layer also features imprints from oceanic mesoscale. Energy injection by scales shorter than 300km represents up to 20% of the total. Finally we show that increasing oceanic resolution, and therefore mesoscale activity, is necessary to resolve the full wind stress spectrum and has an upscaling effect by enhancing atmospheric mesoscale, which is larger scale than in the ocean. Using 1/4°oceanic resolution instead of 1/12° leads to a 50% loss of energy in the atmospheric mesoscale.

  10. Occurrence and air/sea-exchange of novel organic pollutants in the marine environment

    NASA Astrophysics Data System (ADS)

    Ebinghaus, R.; Xie, Z.

    2006-12-01

    A number of studies have demonstrated that several classes of chemicals act as biologically relevant signalling substances. Among these chemicals, many, including PCBs, DDT and dioxins, are semi-volatile, persistent, and are capable of long-range atmospheric transport via atmospheric circulation. Some of these compounds, e.g. phthalates and alkylphenols (APs) are still manufactured and consumed worldwide even though there is clear evidence that they are toxic to aquatic organisms and can act as endocrine disruptors. Concentrations of NP, t-OP and NP1EO, DMP, DEP, DBP, BBP, and DEHP have been simultaneously determined in the surface sea water and atmosphere of the North Sea. Atmospheric concentrations of NP and t-OP ranged from 7 to 110 pg m - 3, which were one to three orders of magnitude below coastal atmospheric concentrations already reported. NP1EO was detected in both vapor and particle phases, which ranged from 4 to 50 pg m - 3. The concentrations of the phthalates in the atmosphere ranged from below the method detection limit to 3.4 ng m - 3. The concentrations of t-OP, NP, and NP1EO in dissolved phase were 13-300, 90-1400, and 17-1660 pg L - 1. DBP, BBP, and DEHP were determined in the water phase with concentrations ranging from below the method detection limit to 6.6 ng L - 1. This study indicates that atmospheric deposition of APs and phthalates into the North Sea is an important input pathway. The net fluxes indicate that the air sea exchange is significant and, consequently the open ocean and polar areas will be an extensive sink for APs and phthalates.

  11. Atmospheric organochlorine pollutants and air-sea exchange of hexachlorocyclohexane in the Bering and Chukchi Seas

    USGS Publications Warehouse

    Hinckley, D.A.; Bidleman, T.F.; Rice, C.P.

    1991-01-01

    Organochlorine pesticides have been found in Arctic fish, marine mammals, birds, and plankton for some time. The lack of local sources and remoteness of the region imply long-range transport and deposition of contaminants into the Arctic from sources to the south. While on the third Soviet-American Joint Ecological Expedition to the Bering and Chukchi Seas (August 1988), high-volume air samples were taken and analyzed for organochlorine pesticides. Hexachlorocyclohexane (HCH), hexachlorobenzene, polychlorinated camphenes, and chlordane (listed in order of abundance, highest to lowest) were quantified. The air-sea gas exchange of HCH was estimated at 18 stations during the cruise. Average alpha-HCH concentrations in concurrent atmosphere and surface water samples were 250 pg m-3 and 2.4 ng L-1, respectively, and average gamma-HCH concentrations were 68 pg m-3 in the atmosphere and 0.6 ng L-1 in surface water. Calculations based on experimentally derived Henry's law constants showed that the surface water was undersaturated with respect to the atmosphere at most stations (alpha-HCH, average 79% saturation; gamma-HCH, average 28% saturation). The flux for alpha-HCH ranged from -47 ng m-2 day-1 (sea to air) to 122 ng m-2 d-1 (air to sea) and averaged 25 ng m-2 d-1 air to sea. All fluxes of gamma-HCH were from air to sea, ranged from 17 to 54 ng m-2 d-1, and averaged 31 ng m-2 d-1.

  12. Atmospheric organochlorine pollutants and air-sea exchange of hexachlorocyclohexane in the Bering and Chukchi seas

    NASA Astrophysics Data System (ADS)

    Hinckley, Daniel A.; Bidleman, Terry F.; Rice, Clifford P.

    1991-04-01

    Organochlorine pesticides have been found in Arctic fish, marine mammals, birds, and plankton for some time. The lack of local sources and remoteness of the region imply long-range transport and deposition of contaminants into the Arctic from sources to the south. While on the third Soviet-American Joint Ecological Expedition to the Bering and Chukchi Seas (August 1988), high-volume air samples were taken and analyzed for Organochlorine pesticides. Hexachlorocyclohexane (HCH), hexachlorobenzene, polychlorinated camphenes, and chlordane (listed in order of abundance, highest to lowest) were quantified. The air-sea gas exchange of HCH was estimated at 18 stations during the cruise. Average α-HCH concentrations in concurrent atmosphere and surface water samples were 250 pg m-3 and 2.4 ng L-1, respectively, and average γ-HCH concentrations were 68 pg m-3 in the atmosphere and 0.6 ng L-1 in surface water. Calculations based on experimentally derived Henry's law constants showed that the surface water was undersaturated with respect to the atmosphere at most stations (α-HCH, average 79% saturation; γ-HCH, average 28% saturation). The flux for α-HCH ranged from -47 ng m-2 day-1 (sea to air) to 122 ng m-2 d-1 (air to sea) and averaged 25 ng m-2 d-1 air to sea. All fluxes of γ-HCH were from air to sea, ranged from 17 to 54 ng m-2 d-1, and averaged 31 ng m-2 d-1.

  13. Biases in the air-sea flux of CO2 resulting from ocean surface temperature gradients

    NASA Astrophysics Data System (ADS)

    Ward, B.; Wanninkhof, R.; McGillis, W. R.; Jessup, A. T.; Degrandpre, M. D.; Hare, J. E.; Edson, J. B.

    2004-08-01

    The difference in the fugacities of CO2 across the diffusive sublayer at the ocean surface is the driving force behind the air-sea flux of CO2. Bulk seawater fugacity is normally measured several meters below the surface, while the fugacity at the water surface, assumed to be in equilibrium with the atmosphere, is measured several meters above the surface. Implied in these measurements is that the fugacity values are the same as those across the diffusive boundary layer. However, temperature gradients exist at the interface due to molecular transfer processes, resulting in a cool surface temperature, known as the skin effect. A warm layer from solar radiation can also result in a heterogeneous temperature profile within the upper few meters of the ocean. Here we describe measurements carried out during a 14-day study in the equatorial Pacific Ocean (GasEx-2001) aimed at estimating the gradients of CO2 near the surface and resulting flux anomalies. The fugacity measurements were corrected for temperature effects using data from the ship's thermosalinograph, a high-resolution profiler (SkinDeEP), an infrared radiometer (CIRIMS), and several point measurements at different depths on various platforms. Results from SkinDeEP show that the largest cool skin and warm layer biases occur at low winds, with maximum biases of -4% and +4%, respectively. Time series ship data show an average CO2 flux cool skin retardation of about 2%. Ship and drifter data show significant CO2 flux enhancement due to the warm layer, with maximums occurring in the afternoon. Temperature measurements were compared to predictions based on available cool skin parameterizations to predict the skin-bulk temperature difference, along with a warm layer model.

  14. An assessment of air-sea heat fluxes from ocean and coupled reanalyses

    NASA Astrophysics Data System (ADS)

    Valdivieso, Maria; Haines, Keith; Balmaseda, Magdalena; Chang, You-Soon; Drevillon, Marie; Ferry, Nicolas; Fujii, Yosuke; Köhl, Armin; Storto, Andrea; Toyoda, Takahiro; Wang, Xiaochun; Waters, Jennifer; Xue, Yan; Yin, Yonghong; Barnier, Bernard; Hernandez, Fabrice; Kumar, Arun; Lee, Tong; Masina, Simona; Andrew Peterson, K.

    2015-10-01

    Sixteen monthly air-sea heat flux products from global ocean/coupled reanalyses are compared over 1993-2009 as part of the Ocean Reanalysis Intercomparison Project (ORA-IP). Objectives include assessing the global heat closure, the consistency of temporal variability, comparison with other flux products, and documenting errors against in situ flux measurements at a number of OceanSITES moorings. The ensemble of 16 ORA-IP flux estimates has a global positive bias over 1993-2009 of 4.2 ± 1.1 W m-2. Residual heat gain (i.e., surface flux + assimilation increments) is reduced to a small positive imbalance (typically, +1-2 W m-2). This compensation between surface fluxes and assimilation increments is concentrated in the upper 100 m. Implied steady meridional heat transports also improve by including assimilation sources, except near the equator. The ensemble spread in surface heat fluxes is dominated by turbulent fluxes (>40 W m-2 over the western boundary currents). The mean seasonal cycle is highly consistent, with variability between products mostly <10 W m-2. The interannual variability has consistent signal-to-noise ratio (~2) throughout the equatorial Pacific, reflecting ENSO variability. Comparisons at tropical buoy sites (10°S-15°N) over 2007-2009 showed too little ocean heat gain (i.e., flux into the ocean) in ORA-IP (up to 1/3 smaller than buoy measurements) primarily due to latent heat flux errors in ORA-IP. Comparisons with the Stratus buoy (20°S, 85°W) over a longer period, 2001-2009, also show the ORA-IP ensemble has 16 W m-2 smaller net heat gain, nearly all of which is due to too much latent cooling caused by differences in surface winds imposed in ORA-IP.

  15. Air-sea boundary layer dynamics in the presence of mesoscale surface currents

    NASA Astrophysics Data System (ADS)

    Rooth, Claes; Xie, Lian

    1992-09-01

    In the presence of surface currents, a shear stress at the air-sea interface is induced by the surface currents. In the case of a unidirectional current, a quadratic stress law leads to a stress curl proportional to and opposing the surface current vorticity even with a uniform wind. This causes a spindown effect on the surface vorticity field at a rate proportional to the wind speed. In the steady state, or in slowly varying processes which can be treated as parametrically developing quasi-steady states, the surface-layer potential vorticity modulation causes upwelling and downwelling patterns associated with the surface-current vorticity. These effects are analyzed for an idealized jet current, and for a physical situation characteristic of a Gulf Stream boundary ring along the Florida Keys, where the induced transport patterns may be important for onshore transport of fish and spiny lobster larvae, as well as for onshore transport to the Florida Keys of general flotsam transported past them by the Gulf Stream. The spindown time scale (t*) for a 1.5-layer system is H/( ρ'cdVa) for a surface jet on the deformation radius scale (where H is the thickness of the surface layer, Va the surface wind speed, ρ' the air to water density ratio and cd the surface drag coefficient) and increases for large horizontal scales in proportion to the current width squared. For a typical wind speed of 5 m/s and a density normalized drag coefficient ρ'cd= 2 × 10-6, t* is on the order of 1 month for a 30-m surface layer. In the more general case of a stratified interior water column, the vorticity spindown directly affects only the potential vorticity of the surface layer and generally leads to subsurface velocity and vorticity maxima for mesoscale eddies and jets.

  16. User experience interaction design for digital educational games

    NASA Astrophysics Data System (ADS)

    Yuan, Jiugen; Zhang, Wenting; Xing, Ruonan

    2014-04-01

    Leading the elements of games into education is the newest teaching concepts in the field of educational technology, which is by using healthy games to impel and preserve the learner's motivation, improve the learning efficiency and bring one experience in learning something by playing games. First of all, this article has introduced the concept of Digital Game and User Experience and brought the essence of Digital Game to light to construct the frame of user experience interaction design for digital educational games and offer one design idea for the development of related products and hoping that Digital Game will bring us continuous innovation experience.

  17. Solar Array Module Plasma Interaction Experiment (SAMPIE): Technical requirements document

    NASA Technical Reports Server (NTRS)

    Hillard, G. Barry; Ferguson, Dale C.

    1992-01-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a NASA shuttle space flight experiment scheduled for launch in early 1994. The SAMPIE experiment will investigate plasma interactions of high voltage space power systems in low earth orbit. Solar cell modules, representing several technologies, will be biased to high voltages to characterize both arcing and plasma current collection. Other solar modules, specially modified in accordance with current theories of arcing and breakdown, will demonstrate the possibility of arc suppression. Finally, several test modules will be included to study the basic nature of these interactions. The science and technology goals for the project are defined in the Technical Requirements Document (TRD) which is presented here.

  18. The Plasma Interaction Experiment (PIX) description and test program. [electrometers

    NASA Technical Reports Server (NTRS)

    Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

    1978-01-01

    The plasma interaction experiment (PIX) is a battery powered preprogrammed auxiliary payload on the LANDSAT-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

  19. Inquiry style interactive virtual experiments: a case on circular motion

    NASA Astrophysics Data System (ADS)

    Zhou, Shaona; Han, Jing; Pelz, Nathaniel; Wang, Xiaojun; Peng, Liangyu; Xiao, Hua; Bao, Lei

    2011-11-01

    Interest in computer-based learning, especially in the use of virtual reality simulations is increasing rapidly. While there are good reasons to believe that technologies have the potential to improve teaching and learning, how to utilize the technology effectively in teaching specific content difficulties is challenging. To help students develop robust understandings of correct physics concepts, we have developed interactive virtual experiment simulations that have the unique feature of enabling students to experience force and motion via an analogue joystick, allowing them to feel the applied force and simultaneously see its effects. The simulations provide students learning experiences that integrate both scientific representations and low-level sensory cues such as haptic cues under a single setting. In this paper, we introduce a virtual experiment module on circular motion. A controlled study has been conducted to evaluate the impact of using this virtual experiment on students' learning of force and motion in the context of circular motion. The results show that the interactive virtual experiment method is preferred by students and is more effective in helping students grasp the physics concepts than the traditional education method such as problem-solving practices. Our research suggests that well-developed interactive virtual experiments can be useful tools in teaching difficult concepts in science.

  20. Direct neutrino mass experiments and exotic charged current interactions

    NASA Astrophysics Data System (ADS)

    Ludl, Patrick Otto; Rodejohann, Werner

    2016-06-01

    We study the effect of exotic charged current interactions on the electron energy spectrum in tritium decay, focussing on the KATRIN experiment and a possible modified setup that has access to the full spectrum. Both sub-eV and keV neutrino masses are considered. We perform a fully relativistic calculation and take all possible new interactions into account, demonstrating the possible sizable distortions in the energy spectrum.

  1. Ten years of experience from interactive ergonomics projects.

    PubMed

    Eklund, J; Karltun, J

    2012-01-01

    This paper highlights experiences from ergonomics projects, applying an interactive research approach. The aim of this paper is to summarise experiences from seven interactive ergonomics projects with the aim to improve ergonomics and organizational performance jointly. Results from these seven projects were analysed with a model for assessing sustainable change, including the factors active ownership, professional management, competent project leadership, and involved participants. All factors were found giving support to impact and sustainability of the change projects. However, the role of the researcher is difficult and demanding. PMID:22317471

  2. Solar array experiments on the SPHINX satellite. [Space Plasma High voltage INteraction eXperiment satellite

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.

    1974-01-01

    The Space Plasma, High Voltage Interaction Experiment (SPHINX) is the name given to an auxiliary payload satellite scheduled to be launched in January 1974. The principal experiments carried on this satellite are specifically designed to obtain the engineering data on the interaction of high voltage systems with the space plasma. The classes of experiments are solar array segments, insulators, insulators with pin holes and conductors. The satellite is also carrying experiments to obtain flight data on three new solar array configurations: the edge illuminated-multijunction cells, the teflon encased cells, and the violet cells.

  3. Distributions and air-sea fluxes of carbon dioxide in the Western Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Gao, Zhongyong; Chen, Liqi; Sun, Heng; Chen, Baoshan; Cai, Wei-Jun

    2012-12-01

    The uptake of carbon dioxide (CO2) by the Arctic Ocean is most likely increasing because of the rapid sea-ice retreat that lifted the barriers preventing gas exchange and light penetration for biological growth. Measurements of atmospheric and surface sea water partial pressure of CO2 (pCO2) were conducted during the Chinese National Arctic Research Expedition (CHINARE) cruises from July to September in 2003 and 2008. The latitudinal distribution of pCO2 along the 169°W transect showed a below-atmopsheric pCO2 level in most of the Western Arctic Ocean, with distinct regional differences from Bering Strait northward to the Central Acrctic Ocean. The average air-sea CO2 fluxes on the shelf and slope of the Chukchi Sea were -17.0 and -8.1 mmol m-2 d-1 respectively. In the ice-free zone, the partially ice-covered zone, and the heavily ice-covered zone of the Canada Basin, the fluxes were -4.2, -8.6, -2.5 mmol m-2 d-1 respectively. These rates are lower than other recent estimates. Our new results not only confirmed previous observations that most areas of the Western Arctic Ocean were a CO2 sink in general, but they also revealed that the previously unsampled central basins were a moderate CO2 sink. Analysis of controlling factors in different areas shows that pCO2 in Bering Strait was influenced not only by the Bering inflow waters but also by the high biological production. However, pCO2 fluctuated sharply because of strong water mixing both laterally and vertically. In the marginal ice zone (Chukchi Sea), pCO2 was controlled by ice melt and biological production, both of which would decrease pCO2 onshore of the ice edge. In the nearly ice-free southern Canada Basin, pCO2 increasd latitudinally as a result of atmospheric CO2 uptake due to intensive gas exchange, increased temperature, and decresed biological CO2 uptake due to limited nutrient supply. Finally, pCO2 was moderately lower than the atmospheric value and was relatively stable under the ice sheet of the

  4. Spatiotemporal variability and drivers of pCO2 and air-sea CO2 fluxes in the California Current System: an eddy-resolving modeling study

    NASA Astrophysics Data System (ADS)

    Turi, G.; Lachkar, Z.; Gruber, N.

    2013-08-01

    nutrient concentrations of the upwelled waters a primary determinant of the overall source/sink nature of the CalCS. The comparison of the standard simulation with one for preindustrial conditions show that the CalCS is taking up anthropogenic CO2 at a rate of about -1 mol C m-2 yr-1, implying that the region was a small source of CO2 to the atmosphere in preindustrial times. The air-sea CO2 fluxes vary substantially in time, both on seasonal and sub-seasonal timescales, largely driven by variations in surface ocean pCO2. There are important differences among the subregions. Notably, the total variance of the fluxes in the central nearshore CalCS is roughly 4-5 times larger than elsewhere. Most of the variability in pCO2 is associated with the seasonal cycle, except in the nearshore, where sub-seasonal variations driven by mesoscale processes dominate. In the regions offshore of 100 km, changes in surface temperature are the main driver, while in the nearshore region, changes in surface temperature, as well as anomalies in DIC and alkalinity (Alk) owing to changes in circulation, biological productivity and air-sea CO2 fluxes dominate. The dominance of eddy-driven variability in the nearshore 100 km leads to a complex spatiotemporal mosaic of surface ocean pCO2 and air-sea CO2 fluxes that require a substantial observational effort to determine the source/sink nature of this region reliably.

  5. Statistically designed experiments to screen chemical mixtures for possible interactions.

    PubMed Central

    Groten, J P; Tajima, O; Feron, V J; Schoen, E D

    1998-01-01

    For the accurate analysis of possible interactive effects of chemicals in a defined mixture, statistical designs are necessary to develop clear and manageable experiments. For instance, factorial designs have been successfully used to detect two-factor interactions. Particularly useful for this purpose are fractionated factorial designs, requiring only a fraction of all possible combinations of a full factorial design. Once the potential interaction has been detected with a fractionated design, a more accurate analysis can be performed for the particular binary mixtures to ensure and characterize these interactions. In this paper this approach is illustrated using an in vitro cytotoxicity assay to detect the presence of mixtures of Fusarium mycotoxins in contaminated food samples. We have investigated interactions between five mycotoxin species (Trichothecenes, Fumonisins, and Zearalenone) using the DNA synthesis inhibition assay in L929 fibroblasts. First, a central composite design was applied to identify possible interactive effects between mycotoxins in the mixtures (27 combinations from 5(5) possible combinations). Then two-factor interactions of particular interest were further analyzed by the use of a full factorial design (5 x 5 design) to characterize the nature of those interactions more precisely. Results show that combined exposure to several classes of mycotoxins generally results in effect addition with a few minor exceptions indicating synergistic interactions. In general, the nature of the interactions characterized in the full factorial design was similar to the nature of those observed in the central composite design. However, the magnitude of interaction was relatively small in the full factorial design. PMID:9860893

  6. Interactive Plasma Physics Education Using Data from Fusion Experiments

    NASA Astrophysics Data System (ADS)

    Calderon, Brisa; Davis, Bill; Zwicker, Andrew

    2010-11-01

    The Internet Plasma Physics Education Experience (IPPEX) website was created in 1996 to give users access to data from plasma and fusion experiments. Interactive material on electricity, magnetism, matter, and energy was presented to generate interest and prepare users to understand data from a fusion experiment. Initially, users were allowed to analyze real-time and archival data from the Tokamak Fusion Test Reactor (TFTR) experiment. IPPEX won numerous awards for its novel approach of allowing users to participate in ongoing research. However, the latest revisions of IPPEX were in 2001 and the interactive material is no longer functional on modern browsers. Also, access to real-time data was lost when TFTR was shut down. The interactive material on IPPEX is being rewritten in ActionScript3.0, and real-time and archival data from the National Spherical Tokamak Experiment (NSTX) will be made available to users. New tools like EFIT animations, fast cameras, and plots of important plasma parameters will be included along with an existing Java-based ``virtual tokamak.'' Screenshots from the upgraded website and future directions will be presented.

  7. MINER{nu}A, a Neutrino--Nucleus Interaction Experiment

    SciTech Connect

    Solano Salinas, C. J.; Chamorro, A.; Romero, C.

    2007-10-26

    With the fantastic results of KamLAND and SNO for neutrino physics, a new generation of neutrino experiments are being designed and build, specially to study the neutrino oscillations to resolve most of the incognita still we have in the neutrino physics. At FERMILAB we have the experiments MINOS and, in a near future, NO{nu}A, to study this kind of oscillations. One big problem these experiments will have is the lack of a good knowledge of the Physics of neutrino interactions with matter, and this will generate big systematic errors. MINER{nu}A, also at FERMILAB, will cover this space studying with high statistics and great precision the neutrino--nucleus interactions.

  8. Effect of Sampling Depth on Air-Sea CO2 Flux Estimates in River-Stratified Arctic Coastal Waters

    NASA Astrophysics Data System (ADS)

    Miller, L. A.; Papakyriakou, T. N.

    2015-12-01

    In summer-time Arctic coastal waters that are strongly influenced by river run-off, extreme stratification severely limits wind mixing, making it difficult to effectively sample the surface 'mixed layer', which can be as shallow as 1 m, from a ship. During two expeditions in southwestern Hudson Bay, off the Nelson, Hayes, and Churchill River estuaries, we confirmed that sampling depth has a strong impact on estimates of 'surface' pCO2 and calculated air-sea CO2 fluxes. We determined pCO2 in samples collected from 5 m, using a typical underway system on the ship's seawater supply; from the 'surface' rosette bottle, which was generally between 1 and 3 m; and using a niskin bottle deployed at 1 m and just below the surface from a small boat away from the ship. Our samples confirmed that the error in pCO2 derived from typical ship-board versus small-boat sampling at a single station could be nearly 90 μatm, leading to errors in the calculated air-sea CO2 flux of more than 0.1 mmol/(m2s). Attempting to extrapolate such fluxes over the 6,000,000 km2 area of the Arctic shelves would generate an error approaching a gigamol CO2/s. Averaging the station data over a cruise still resulted in an error of nearly 50% in the total flux estimate. Our results have implications not only for the design and execution of expedition-based sampling, but also for placement of in-situ sensors. Particularly in polar waters, sensors are usually deployed on moorings, well below the surface, to avoid damage and destruction from drifting ice. However, to obtain accurate information on air-sea fluxes in these areas, it is necessary to deploy sensors on ice-capable buoys that can position the sensors in true 'surface' waters.

  9. The influence of sea ice cover on air-sea gas exchange estimated with radon-222 profiles

    NASA Astrophysics Data System (ADS)

    Rutgers van der Loeff, Michiel M.; Cassar, Nicolas; Nicolaus, Marcel; Rabe, Benjamin; Stimac, Ingrid

    2014-05-01

    Air-sea gas exchange plays a key role in the cycling of greenhouse and other biogeochemically important gases. Although air-sea gas transfer is expected to change as a consequence of the rapid decline in summer Arctic sea ice cover, little is known about the effect of sea ice cover on gas exchange fluxes, especially in the marginal ice zone. During the Polarstern expedition ARK-XXVI/3 (TransArc, August/September 2011) to the central Arctic Ocean, we compared 222Rn/226Ra ratios in the upper 50 m of 14 ice-covered and 4 ice-free stations. At three of the ice-free stations, we find 222Rn-based gas transfer coefficients in good agreement with expectation based on published relationships between gas transfer and wind speed over open water when accounting for wind history from wind reanalysis data. We hypothesize that the low gas transfer rate at the fourth station results from reduced fetch due to the proximity of the ice edge, or lateral exchange across the front at the ice edge by restratification. No significant radon deficit could be observed at the ice-covered stations. At these stations, the average gas transfer velocity was less than 0.1 m/d (97.5% confidence), compared to 0.5-2.2 m/d expected for open water. Our results show that air-sea gas exchange in an ice-covered ocean is reduced by at least an order of magnitude compared to open water. In contrast to previous studies, we show that in partially ice-covered regions, gas exchange is lower than expected based on a linear scaling to percent ice cover.

  10. The FETCH experiment: An overview

    NASA Astrophysics Data System (ADS)

    Hauser, D.; Branger, H.; Bouffies-Cloché, S.; Despiau, S.; Drennan, W. M.; Dupuis, H.; Durand, P.; Durrieu de Madron, X.; Estournel, C.; Eymard, L.; Flamant, C.; Graber, H. C.; GuéRin, C.; Kahma, K.; Lachaud, G.; LefèVre, J.-M.; Pelon, J.; Pettersson, H.; Piguet, B.; Queffeulou, P.; Tailliez, D.; Tournadre, J.; Weill, A.

    2003-03-01

    The "flux, etat de la mer, et télédétection en conditions de fetch variable" (FETCH) was aimed at studying the physical processes associated with air-sea exchanges and mesoscale oceanic circulation in a coastal region dominated by frequent strong offshore winds. The experiment took place in March-April 1998 in the northwestern Mediterranean Sea (Gulf of Lion). Observations were collected with the R/V L'Atalante, with an air-sea interaction spar (ASIS) buoy, with waverider buoys, and with research aircraft equipped for in situ and remote sensing measurements. The present paper is an introduction to the following special section, which groups 12 papers (including this one) presenting results on turbulent flux measurements at the ocean surface, on the behavior of the marine atmospheric boundary layer, on the ocean waves characteristics, on the ocean circulation, and on remote sensing of surface parameters. This overview presents the background and objectives of FETCH, the experimental setup and operations, and the dominant atmospheric and oceanic conditions and introduces the different papers of the special section.

  11. VLF wave-wave interaction experiments in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Chang, D. C. D.

    1978-01-01

    VLF wave-wave interaction experiments were carried out by injecting various forms of VLF pulses into the magnetosphere from a 21.2 km dipole antenna at Siple, Antarctica. The injected signals propagate along a geomagnetic field line and often interact strongly with energetic electrons trapped in the radiation belts near the equator. Signals may be amplified and trigger emissions. These signals may then interact with one another through these energetic electrons. This report is divided into three parts. In the first part, simulations of VLF pulses propagating in the magnetosphere are carried out. In the second part, it is found for the first time that a 10 ms gap in a triggering wave can induce emission, which may then interact with the post-gap signals. In the third part, sideband triggering is reported for the first time.

  12. APO observations in Southern Greenland: evaluation of modelled air-sea O2 and CO2 fluxes

    NASA Astrophysics Data System (ADS)

    Bonne, Jean-Louis; Bopp, Laurent; Delmotte, Marc; Cadule, Patricia; Resplandy, Laure; Nevison, Cynthia; Manizza, Manfredi; Valentin Lavric, Jost; Manning, Andrew C.; Masson-Delmotte, Valérie

    2014-05-01

    Since September 2007, the atmospheric CO2 mole fraction and O2/N2 ratio (a proxy for O2 concentration) have been monitored continuously at the coastal site of Ivittuut, southern Greenland (61.21° N, 48.17° W). From 2007 to 2013, our measurements show multi-annual trends of +2.0 ppm/year and -20 per meg/year respectively for CO2 and O2/N2, with annual average peak-to-peak seasonal amplitudes of 14+/-1 ppm and 130+/-15 per meg. We investigate the implications of our data set in terms of APO (Atmospheric Potential Oxygen). This tracer, obtained by a linear combination of CO2 and O2/N2 data, is invariant to CO2 and O2 exchanges in the land biota, but sensitive to the oceanic component of the O2 cycle. It is used as a bridge to evaluate air-sea CO2 and O2 fluxes from atmospheric variations of CO2 and O2/N2. Global ocean biogeochemical models produce estimates of CO2 and O2 air-sea fluxes. Atmospheric APO variations can be simulated through transportation of these fluxes in the atmosphere by Eulerian transport models. Thus, model values of atmospheric APO can be extracted at the station location. This study is based on air-sea flux outputs from CMIP5 simulations. After atmospheric transportation, they give access to atmospheric APO climatologies which can be compared, in terms of seasonal cycles and inter-annual variability, to the in situ observations. A preliminary study is based on the CCSM ocean model air-sea fluxes transported in the atmosphere with the MATCH transport model, over the period 1979-2004. The amplitude of the APO seasonal cycle is correctly captured, but year to year variations on this seasonal cycle appears to be underestimated compared to observations. The LMDZ atmospheric transport model is also used to transport the ocean fluxes from five CMIP5 models, over the period 1979-2005, showing different amplitudes and timings of APO seasonal cycles. This methodology is a first step to evaluate the origin of observed APO variations at our site and then

  13. Telescience operations with the solar array module plasma interaction experiment

    NASA Technical Reports Server (NTRS)

    Wald, Lawrence W.; Bibyk, Irene K.

    1995-01-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a flight experiment that flew on the Space Shuttle Columbia (STS-62) in March 1994, as part of the OAST-2 mission. The overall objective of SAMPIE was to determine the adverse environmental interactions within the space plasma of low earth orbit (LEO) on modern solar cells and space power system materials which are artificially biased to high positive and negative direct current (DC) voltages. The two environmental interactions of interest included high voltage arcing from the samples to the space plasma and parasitic current losses. High voltage arcing can cause physical damage to power system materials and shorten expected hardware life. parasitic current losses can reduce power system efficiency because electric currents generated in a power system drain into the surrounding plasma via parasitic resistance. The flight electronics included two programmable high voltage DC power supplies to bias the experiment samples, instruments to measure the surrounding plasma environment in the STS cargo bay, and the on-board data acquisition system (DAS). The DAS provided in-flight experiment control, data storage, and communications through the Goddard Space Flight Center (GSFC) Hitchhiker flight avionics to the GSFC Payload Operations Control Center (POCC). The DAS and the SAMPIE POCC computer systems were designed for telescience operations; this paper will focus on the experiences of the SAMPIE team regarding telescience development and operations from the GSFC POCC during STS-62. The SAMPIE conceptual development, hardware design, and system verification testing were accomplished at the NASA Lewis Research Center (LeRC). SAMPIE was developed under the In-Space Technology Experiment Program (IN-STEP), which sponsors NASA, industry, and university flight experiments designed to enable and enhance space flight technology. The IN-STEP Program is sponsored by the Office of Space Access and Technology (OSAT).

  14. Telescience operations with the solar array module plasma interaction experiment

    SciTech Connect

    Wald, L.W.; Bibyk, I.K.

    1995-09-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a flight experiment that flew on the Space Shuttle Columbia (STS-62) in March 1994, as part of the OAST-2 mission. The overall objective of SAMPIE was to determine the adverse environmental interactions within the space plasma of low earth orbit (LEO) on modern solar cells and space power system materials which are artificially biased to high positive and negative direct current (DC) voltages. The two environmental interactions of interest included high voltage arcing from the samples to the space plasma and parasitic current losses. High voltage arcing can cause physical damage to power system materials and shorten expected hardware life. Parasitic current losses can reduce power system efficiency because electric currents generated in a power system drain into the surrounding plasma via parasitic resistance. The flight electronics included two programmable high voltage DC power supplies to bias the experiment samples, instruments to measure the surrounding plasma environment in the STS cargo bay, and the on-board data acquisition system (DAS). The DAS provided in-flight experiment control, data storage, and communications through the Goddard Space Flight Center (GSFC) Hitchhiker flight avionics to the GSFC Payload Operations Control Center (POCC). The DAS and the SAMPIE POCC computer systems were designed for telescience operations; this paper will focus on the experiences of the SAMPIE team regarding telescience development and operations from the GSFC POCC during STS-62. The SAMPIE conceptual development, hardware design, and system verification testing were accomplished at the NASA Lewis Research Center (LeRC). SAMPIE was developed under the In-Space Technology Experiment Program (IN-STEP), which sponsors NASA, industry, and university flight experiments designed to enable and enhance space flight technology.

  15. Interactive Lecture Experiments in Large Introductory Physics Classes

    NASA Astrophysics Data System (ADS)

    Milner-Bolotin, Marina M.; Kotlicki, A.; Rieger, G.; Bates, F.; Moll, R.; McPhee, K.; Nashon, S.

    2006-12-01

    We describe Interactive Lecture Experiments (ILE), which build on Interactive Lecture Demonstrations proposed by Sokoloff and Thornton (2004) and extends it by providing students with the opportunity to analyze experiments demonstrated in the lecture outside of the classroom. Real time experimental data is collected, using Logger Pro combined with the digital video technology. This data is uploaded to the Internet and made available to the students for further analysis. Student learning is assessed in the following lecture using conceptual questions (clickers). The goal of this project is to use ILE to make large lectures more interactive and promote student interest in science, critical thinking and data analysis skills. We report on the systematic study conducted using the Colorado Learning Attitudes about Science Survey, Force Concept Inventory, open-ended physics problems and focus group interviews to determine the impact of ILE on student academic achievement, motivation and attitudes towards physics. Three sections of students (750 students) experienced four ILE experiments. The surveys were administered twice and academic results for students who experienced the ILE for a particular topic were compared to the students, from a different section, who did not complete the ILE for that topic. Additional qualitative data on students’ attitudes was collected using open ended survey questions and interviews. We will present preliminary conclusions about the role of ILEs as an effective pedagogy in large introductory physics courses. Sokoloff, D.R. and R.K. Thornton (2004). Interactive Lecture Demonstrations: Active Learning in Introductory Physics, J.Wiley & Sons, INC. Interactive Lecture Experiments: http://www.physics.ubc.ca/ year1lab/p100/LectureLabs/lectureLabs.html

  16. Air-sea exchange of dimethylsulfide in the Southern Ocean: Measurements from SO GasEx compared to temperate and tropical regions

    NASA Astrophysics Data System (ADS)

    Yang, M.; Blomquist, B. W.; Fairall, C. W.; Archer, S. D.; Huebert, B. J.

    2011-04-01

    In the Southern Ocean Gas Exchange Experiment (SO GasEx), we measured an atmospheric dimethylsulfide (DMS) concentration of 118 ± 54 pptv (1σ), a DMS sea-to-air flux of 2.9 ± 2.1 μmol m-2 d-1 by eddy covariance, and a seawater DMS concentration of 1.6 ± 0.7 nM. Dividing flux by the concurrent air-sea concentration difference yields the transfer velocity of DMS (kDMS). The kDMS in the Southern Ocean was significantly lower than previous measurements in the equatorial east Pacific, Sargasso Sea, northeast Atlantic, and southeast Pacific. Normalizing kDMS for the temperature dependence in waterside diffusivity and solubility results in better agreement among various field studies and suggests that the low kDMS in the Southern Ocean is primarily due to colder temperatures. The higher solubility of DMS at a lower temperature results in greater airside control and less transfer of the gas by bubbles formed from breaking waves. The final normalized DMS transfer velocity is similar to k of less soluble gases such as carbon dioxide in low-to-moderate winds; in high winds, DMS transfer velocity is significantly lower because of the reduced bubble-mediated transfer.

  17. Plasma-materials interactions during rf experiments in tokamaks

    SciTech Connect

    Cohen, S.A.; Bernabei, S.; Budny, R.; Chu, T.K.; Colestock, P.; Hinnov, E.; Hooke, W.; Hosea, J.; Hwang, D.; Jobes, F.

    1984-09-01

    Plasma-materials interactions studied in recent ICRF heating and lower hybrid current drive experiments are reviewed. The microscopic processes responsible for impurity generation are discussed. In ICRF experiments, improvements in machine operation and in antenna and feedthrough design have allowed efficient plasma heating at RF powers up to 3 MW. No significant loss of energy from the plasma core due to impurity radiation occurs. Lower hybrid current drive results in the generation and maintenance of hundreds of kiloamperes of plasma current carried by suprathermal electrons. The loss of these electrons and their role in impurity generation are assessed. Methods to avoid this problem are evaluated.

  18. The organic sea surface microlayer in the upwelling region off Peru and implications for air-sea exchange processes

    NASA Astrophysics Data System (ADS)

    Engel, A.; Galgani, L.

    2015-07-01

    The sea surface microlayer (SML) is at the very surface of the ocean, linking the hydrosphere with the atmosphere, and central to a range of global biogeochemical and climate-related processes. The presence and enrichment of organic compounds in the SML have been suggested to influence air-sea gas exchange processes as well as the emission of primary organic aerosols. Among these organic compounds, primarily of plankton origin, are dissolved exopolymers, specifically polysaccharides and proteins, and gel particles, such as Transparent Exopolymer Particles (TEP) and Coomassie Stainable Particles (CSP). These organic substances often accumulate in the surface ocean when plankton productivity is high. Here, we report results obtained in December 2012 during the SOPRAN Meteor 91 cruise to the highly productive, coastal upwelling regime off Peru. Samples were collected from the SML and from ~ 20 cm below, and were analyzed for polysaccharidic and proteinaceous compounds, gel particles, total and dissolved organic carbon, bacterial and phytoplankton abundance. Our study provides insight to the physical and biological control of organic matter enrichment in the SML, and discusses the potential role of organic matter in the SML for air-sea exchange processes.

  19. Air-Sea Exchange and Budget of Sulfur and Oxygen-Containing Volatile Organic Compounds in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Tanimoto, H.; Omori, Y.; Inomata, S.; Iwata, T.; Kameyama, S.

    2015-12-01

    By combining proton transfer reaction-mass spectrometry (PTR-MS) and gradient flux (GF) technique, in situ measurement of air-sea fluxes of multiple volatile organic compounds (VOCs) was developed and deployed. Starting in 2008, we made in situ observations of air-sea fluxes at 15 locations as well as underway observations of marine air/surface seawater bulk concentrations in the Pacific Ocean, during eight research cruises by R/V Hakuho-Maru. The fluxes of biogenic trace gases, DMS and isoprene, were always positive, with the magnitudes being in accordance with previously reported. In contrast, the fluxes of oxygenated VOCs including acetone and acetaldehyde varied from negative to positive, suggesting that the tropical and subtropical Pacific are a source, while the North Pacific is a sink. A basin-scale budget of VOCs were determined for 4 biogeochemical provinces in the Pacific Ocean, and the role of oceans for VOCs were discussed with respect to physical and biogeochemical processes.

  20. Interest enhancements to science experiments: Interactions with student gender

    NASA Astrophysics Data System (ADS)

    Martinez, Michael E.

    Males are more likely than females to aspire to and enter scientific careers, a pattern that might be attributed to gender differences in the appeal of school science. Differences might arise, in part, from gender-related interactions with the interest value of school science experiments. If modifiable, the interest value of experiments could influence attitudes toward science and subsequent choices concerning science involvement. In this study, middle school students carried out versions of science experiments designed to vary in their interest value. Experiment modifications, guided by a three-component model of interest, ranged from introduction of fantasy scenarios to manipulation of the difficulty and social context of the experiments. Subjects were 101 middle school students, 46 males and 55 females. Of primary interest were MANOVA comparisons of self-reported interest in the experiments, by gender and experimental condition. In general, interest enhancements were more effective for girls than boys. Boys were more attentive to aspects of the experiments that elicit perceptions of control, whereas girls were more attentive to social aspects.

  1. Does atmospheric CO2 seasonality play an important role in governing the air-sea flux of CO2?

    NASA Astrophysics Data System (ADS)

    Halloran, P. R.

    2012-06-01

    The amplitude, phase, and form of the seasonal cycle of atmospheric CO2 concentrations varies on many time and space scales (Peters et al., 2007). Intra-annual CO2 variation is primarily driven by seasonal uptake and release of CO2 by the terrestrial biosphere (Machta et al., 1977; Buchwitz et al., 2007), with a small (Cadule et al., 2010; Heimann et al., 1998), but potentially changing (Gorgues et al., 2010) contribution from the ocean. Variability in the magnitude, spatial distribution, and seasonal drivers of terrestrial net primary productivity (NPP) will be induced by, amongst other factors, anthropogenic CO2 release (Keeling et al., 1996), land-use change (Zimov et al., 1999) and planetary orbital variability, and will lead to changes in CO2atm seasonality. Despite CO2atm seasonality being a dynamic and prominent feature of the Earth System, its potential to drive changes in the air-sea flux of CO2 has not previously (to the best of my knowledge) been explored. It is important that we investigate the impact of CO2atm seasonality change, and the potential for carbon-cycle feedbacks to operate through the modification of the CO2atm seasonal cycle, because the decision had been made to prescribe CO2atm concentrations (rather than emissions) within model simulations for the fifth IPCC climate assessment (Taylor et al., 2009). In this study I undertake ocean-model simulations within which different magnitude CO2atm seasonal cycles are prescribed. These simulations allow me to examine the effect of a change in CO2atm seasonal cycle magnitude on the air-sea CO2 flux. I then use an off-line model to isolate the drivers of the identified air-sea CO2 flux change, and propose mechanisms by which this change may come about. Three mechanisms are identified by which co-variability of the seasonal cycles in atmospheric CO2 concentration, and seasonality in sea-ice extent, wind-speed and ocean temperature, could potentially lead to changes in the air-sea flux of CO2 at mid

  2. Laser-plasma-interaction experiments using multikilojoule lasers

    SciTech Connect

    Drake, R.P.

    1987-07-01

    This paper summarizes the results of several laser-plasma-interaction experiments using multikilojoule lasers, and considers their implications for laser fusion. The experiments used 1.06, 0.53, 0.35, and 0.26 ..mu..m light to produce relatively large, warm, planar plasmas and to study the effect of laser wavelength and density-gradient scale length on the Stimulated Raman Scattering and on the scattering of light at frequencies near the incident laser frequency by Stimulated Brillouin Scattering or other processes. The results of these experiments suggest that some laser wavelength between 0.2 and 0.6 ..mu..m will be required for high-gain laser fusion.

  3. The Dynamic Reactance Interaction - How Vested Interests Affect People's Experience, Behavior, and Cognition in Social Interactions.

    PubMed

    Steindl, Christina; Jonas, Eva

    2015-01-01

    In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner's freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor-client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor) or a patient (client). In both studies we incorporated a vested interest. In Study 1 (N = 82) we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N = 207) further demonstrated that doctors expressed their reactance in a subtle way: they revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically. PMID:26640444

  4. Sensitivity of the air-sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short-term variability

    NASA Astrophysics Data System (ADS)

    Lansø, A. S.; Bendtsen, J.; Christensen, J. H.; Sørensen, L. L.; Chen, H.; Meijer, H. A. J.; Geels, C.

    2015-05-01

    Minimising the uncertainties in estimates of air-sea CO2 exchange is an important step toward increasing the confidence in assessments of the CO2 cycle. Using an atmospheric transport model makes it possible to investigate the direct impact of atmospheric parameters on the air-sea CO2 flux along with its sensitivity to, for example, short-term temporal variability in wind speed, atmospheric mixing height and atmospheric CO2 concentration. With this study, the importance of high spatiotemporal resolution of atmospheric parameters for the air-sea CO2 flux is assessed for six sub-basins within the Baltic Sea and Danish inner waters. A new climatology of surface water partial pressure of CO2 (pCO2w) has been developed for this coastal area based on available data from monitoring stations and on-board pCO2w measuring systems. Parameterisations depending on wind speed were applied for the transfer velocity to calculate the air-sea CO2 flux. Two model simulations were conducted - one including short-term variability in atmospheric CO2 (VAT), and one where it was not included (CAT). A seasonal cycle in the air-sea CO2 flux was found for both simulations for all sub-basins with uptake of CO2 in summer and release of CO2 to the atmosphere in winter. During the simulated period 2005-2010, the average annual net uptake of atmospheric CO2 for the Baltic Sea, Danish straits and Kattegat was 287 and 471 Gg C yr-1 for the VAT and CAT simulations, respectively. The obtained difference of 184 Gg C yr-1 was found to be significant, and thus ignoring short-term variability in atmospheric CO2 does have a sizeable effect on the air-sea CO2 exchange. The combination of the atmospheric model and the new pCO2w fields has also made it possible to make an estimate of the marine part of the Danish CO2 budget for the first time. A net annual uptake of 2613 Gg C yr-1 was found for the Danish waters. A large uncertainty is connected to the air-sea CO2 flux in particular caused by the transfer

  5. Sensitivity of the air-sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short term variability

    NASA Astrophysics Data System (ADS)

    Lansø, A. S.; Bendtsen, J.; Christensen, J. H.; Sørensen, L. L.; Chen, H.; Meijer, H. A. J.; Geels, C.

    2014-12-01

    Minimising the uncertainties in estimates of air-sea CO2 exchange is an important step toward increasing the confidence in assessments of the CO2 cycle. Using an atmospheric transport model makes it possible to investigate the direct impact of atmospheric parameters on the air-sea CO2 flux along with its sensitivity to e.g. short-term temporal variability in wind speed, atmospheric mixing height and the atmospheric CO2 concentration. With this study the importance of high spatiotemporal resolution of atmospheric parameters for the air-sea CO2 flux is assessed for six sub-basins within the Baltic Sea and Danish inner waters. A new climatology of surface water partial pressure of CO2 (pCO2) has been developed for this coastal area based on available data from monitoring stations and underway pCO2 measuring systems. Parameterisations depending on wind speed were applied for the transfer velocity to calculate the air-sea CO2 flux. Two model simulations were conducted - one including short term variability in atmospheric CO2 (VAT), and one where it was not included (CAT). A seasonal cycle in the air-sea CO2 flux was found for both simulations for all sub-basins with uptake of CO2 in summer and release of CO2 to the atmosphere in winter. During the simulated period 2005-2010 the average annual net uptake of atmospheric CO2 for the Baltic Sea, Danish Straits and Kattegat was 287 and 471 Gg C yr-1 for the VAT and CAT simulations, respectively. The obtained difference of 184 Gg C yr-1 was found to be significant, and thus ignoring short term variability in atmospheric CO2 does have a sizeable effect on the air-sea CO2 exchange. The combination of the atmospheric model and the new pCO2 fields has also made it possible to make an estimate of the marine part of the Danish CO2 budget for the first time. A net annual uptake of 2613 Gg C yr-1 was found for the Danish waters. A large uncertainty is connected to the air-sea CO2 flux in particular caused by the transfer velocity

  6. Eco-evolutionary experience in novel species interactions.

    PubMed

    Saul, Wolf-Christian; Jeschke, Jonathan M

    2015-03-01

    A better understanding of how ecological novelty influences interactions in new combinations of species is key for predicting interaction outcomes, and can help focus conservation and management efforts on preventing the introduction of novel organisms or species (including invasive species, GMOs, synthetic organisms, resurrected species and emerging pathogens) that seem particularly 'risky' for resident species. Here, we consider the implications of different degrees of eco-evolutionary experience of interacting resident and non-resident species, define four qualitative risk categories for estimating the probability of successful establishment and impact of novel species and discuss how the effects of novelty change over time. Focusing then on novel predator-prey interactions, we argue that novelty entails density-dependent advantages for non-resident species, with their largest effects often being at low prey densities. This is illustrated by a comparison of predator functional responses and prey predation risk curves between novel species and ecologically similar resident species, and raises important issues for the conservation of endangered resident prey species. PMID:25626585

  7. Thermosphere-ionosphere coupling - An experiment in interactive modeling

    NASA Technical Reports Server (NTRS)

    Forbes, Jeffrey M.; Roble, Raymond G.

    1990-01-01

    Using the NCAR thermosphere general circulation model, a series of controlled experiments is performed to investigate the interactive coupling between ionospheric plasma densities and thermospheric neutral winds. The interaction is accomplished by parameterizing the F layer peak height, h(m)F2, in an empirical ionospheric model in terms of the meridional wind, v(south), and by forcing the h(m)F2 and the v(south) parameters to remain mutually coupled in a dynamical calculation. It was found that mutual coupling between forcing and meridional wind is weak during the daytime when the F layer exhibits a broad vertical structure. At night, when the F2 layer is more localized, the neutral dynamical structure is dependent on whether forcing is significantly above or below the altitude (about 275-300 km) at which ion drag effectively competes with viscosity in the neutral momentum balance.

  8. Neutrino-nucleus interactions in the T2K experiment

    SciTech Connect

    Leitner, T.; Mosel, U.

    2010-09-15

    We present a study of neutrino-nucleus interactions at the T2K experiment based on the GiBUU transport model. The aim of T2K is to measure {nu}{sub e} appearance and {theta}{sub 13}, but it will also be able to do a precise measurement of {nu}{sub {mu}}disappearance. The former requires a good understanding of {pi}{sup 0} production, while the latter is closely connected with a good understanding of quasielastic scattering. For both processes we investigate the influence of nuclear effects and particular final-state interactions on the expected event rates, taking into account the T2K detector setup.

  9. Constraining the nonstandard interaction parameters in long baseline neutrino experiments

    NASA Astrophysics Data System (ADS)

    Huitu, Katri; Kärkkäinen, Timo J.; Maalampi, Jukka; Vihonen, Sampsa

    2016-03-01

    In this article we investigate the prospects for probing the strength of the possible nonstandard neutrino interactions (NSI) in long baseline neutrino oscillation experiments. We find that these experiments are sensitive to NSI couplings down to the level of 0.01-0.1 depending on the oscillation channel and the baseline length, as well as on the detector's fiducial mass. We also investigate the interference of the leptonic C P angle δC P with the constraining of the NSI couplings. It is found that the interference is strong in the case of the νe↔νμ and νe↔ντ transitions but not significant in other transitions. In our numerical analysis we apply the GLoBES software and use the LBNO setup as our benchmark.

  10. Air-sea CO2 fluxes measured by eddy covariance in a coastal station in Baja California, México

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Loza, L.; Ocampo-Torres, F. J.

    2016-05-01

    The influence of wave-associated parameters controlling turbulent CO2 fluxes through the air-sea water interface is evaluated in a coastal region. The study area, located within the Todos Santos Bay, Baja California, México, was found to be a weak sink of CO2 with a mean flux of -1.32 µmol m-2s-1. The low correlation found between flux and wind speed (r = 0.09), suggests that the influence of other forcing mechanisms, besides wind, is important for gas transfer modulation through the sea surface, at least for the conditions found in this study. In addition, the results suggest that for short periods where an intensification of the wave conditions occurs, a CO2 flux response increases the transport of gas to the ocean.

  11. Using wind setdown and storm surge on Lake Erie to calibrate the air-sea drag coefficient.

    PubMed

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

  12. Using Wind Setdown and Storm Surge on Lake Erie to Calibrate the Air-Sea Drag Coefficient

    PubMed Central

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

  13. Dissolved methane concentration profiles and air-sea fluxes from 41°S to 27°N

    NASA Astrophysics Data System (ADS)

    Kelley, Cheryl A.; Jeffrey, Wade H.

    2002-07-01

    Water column samples from a transect cruise from southern Chile through the Panama Canal to the Gulf of Mexico were used to determine dissolved methane depth profiles and air-sea methane fluxes. In the Gulf of Mexico, surface concentrations were approximately 40% supersaturated with respect to the atmosphere, whereas near the equator and in the Peru upwelling region, 10-20% supersaturation generally occurred. These saturation ratios translate into an average flux of methane from the sea surface to the atmosphere of 0.38 μmol m-2 d-1. In addition, water column profiles of dissolved methane indicate that subsurface maxima in dissolved methane concentrations are a consistent feature of the open ocean, except near the equator. At the equator, the subsurface peak at the base of the mixed layer may be bowed down by the Equatorial Undercurrent. The highest methane concentration (12 nM) was observed in the Peru upwelling region.

  14. Temporal variations in air-sea CO2 exchange near large kelp beds near San Diego, California

    NASA Astrophysics Data System (ADS)

    Ikawa, Hiroki; Oechel, Walter C.

    2015-01-01

    study presents nearly continuous air-sea CO2 flux for 7 years using the eddy covariance method for nearshore water near San Diego, California, as well as identifying environmental processes that appear to control temporal variations in air-sea CO2 flux at different time scales using time series decomposition. Monthly variations in CO2 uptake are shown to be positively influenced by photosynthetically active photon flux density (PPFD) and negatively related to wind speeds. In contrast to the monthly scale, wind speeds often influenced CO2 uptake positively on an hourly scale. Interannual variations in CO2 flux were not correlated with any independent variables, but did reflect surface area of the adjacent kelp bed in the following year. Different environmental influences on CO2 flux at different temporal scales suggest the importance of long-term flux monitoring for accurately identifying important environmental processes for the coastal carbon cycle. Overall, the study area was a strong CO2 sink into the sea (CO2 flux of ca. -260 g C m-2 yr-1). If all coastal areas inhabited by macrophytes had a similar CO2 uptake rate, the net CO2 uptake from these areas alone would roughly equal the net CO2 sink estimated for the entire global coastal ocean to date. A similar-strength CO2 flux, ranging between -0.09 and -0.01 g C m-2 h-1, was also observed over another kelp bed from a pilot study of boat-based eddy covariance measurements.

  15. A review of the sources of uncertainties when estimating global-scale turbulent air-sea fluxes

    NASA Astrophysics Data System (ADS)

    Brodeau, Laurent; Barnier, Bernard

    2015-04-01

    Bulk formulae are used to estimate turbulent air-sea fluxes needed to provide surface boundary conditions to most of present-day OGCMs, AGCMs and coupled Earth systems. This study aims at making an inventory of the major sources of uncertainties and errors made when estimating turbulent air-sea fluxes with the bulk method, namely wind stress, evaporation (latent heat flux) and sensible heat flux. We use 6-hourly near-surface atmospheric fields and daily SST of ERA-Interim to compute global estimates of these fluxes during the last three decades. Those fluxes are computed using different bulk routines and different types of physical and numerical simplifications widely used within the GCM community. Moreover, to assess the sensitivity of these flux estimates to possible errors in the input atmospheric fields and SST, user-controlled biases are applied to each of these fields prior to bulk computation. As a result, a quantification of the potential sources of uncertainties related to the accuracy of both the parametrization and input fields is proposed. Any parametrization-related approximation can also be expressed in terms of a bias on a given input field. We find that the largest source of flux uncertainties is the choice of the bulk algorithm used to estimate the bulk transfer coefficients. The resulting disagreement in terms of globally-averaged heat flux and evaporation is 8 W/m2 and 1 Sv. In mid latitudes, this heat flux disagreement is about 10 W/m2, which independently compares to a bias of 1 m/s in surface wind speed, 3° in SST, 0.5° in surface temperature, or a modification of 5% in the surface humidity. Our study also underlies the relative importance of the accuracy of the estimate of the air density and the specific humidity at saturation.

  16. Experiments Evaluating the Interaction between Deformable Substrates and Prograding Clinoforms

    NASA Astrophysics Data System (ADS)

    Chatmas, E. S.; Foreman, B.; Abeyta, A.; Paola, C.

    2013-12-01

    Passive margins often contain salt and mobile shale layers that act as deformable substrates underlying coastal sediments. By understanding the interaction between deformable substrates and migrating clinoforms in simplified, experimental settings, we hope to clarify their fundamental behavior in natural deltaic settings. Substrate deformation occurs by a number of processes and can result in rugose ocean floor bathymetry which can locally trap sediment. In our experiments, we focus on how differential sediment loading on two substrates of different rheologies (Newtonian versus Bingham) affects aspects of clinoform deposition. We are particularly interested in the effects of the progradation rate and substrate rheology on the locus of clinoform deposition over time as the substrate and delta interact. Our experimental setup uses a rectangular flume that is 230 cm long, 8 cm wide and 30 cm tall. The materials we used for the mobile shale experiments involved a mixture of kaolinite and water which provide a Bingham rheology, and the sediment was a quartz sand and coal mixture. For a Newtonian rheology we used corn syrup as a deformable substrate, capturing the Newtonian rheology of subsurface salt, and the sediment consisted of a mixture of equal volumes of walnut shells and kaolinite clay. For each experiment we systematically changed sediment feed rate and substrate thickness. Deformation styles differ qualitatively between Bingham (kaolinite/mobile shale) and Newtonian (corn syrup/salt) experiments. In mobile-shale (Bingham) experiments, a bulge forms at the toe of the clinoform and the clinoform eventually overtops this bulge, creating alternating thick and thin stratigraphic accumulations down depositional dip. For the salt (Newtonian) experiments, deformation occurs behind the clinoform foreset in the form of diapirs. Preliminary results show minimal impacts on shoreline progradation rate as the delta loads mobile shale substrates. This suggests that the

  17. RANS Modeling of Benchmark Shockwave / Boundary Layer Interaction Experiments

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nick; Vyas, Manan; Yoder, Dennis

    2010-01-01

    This presentation summarizes the computations of a set of shock wave / turbulent boundary layer interaction (SWTBLI) test cases using the Wind-US code, as part of the 2010 American Institute of Aeronautics and Astronautics (AIAA) shock / boundary layer interaction workshop. The experiments involve supersonic flows in wind tunnels with a shock generator that directs an oblique shock wave toward the boundary layer along one of the walls of the wind tunnel. The Wind-US calculations utilized structured grid computations performed in Reynolds-averaged Navier-Stokes mode. Three turbulence models were investigated: the Spalart-Allmaras one-equation model, the Menter Shear Stress Transport wavenumber-angular frequency two-equation model, and an explicit algebraic stress wavenumber-angular frequency formulation. Effects of grid resolution and upwinding scheme were also considered. The results from the CFD calculations are compared to particle image velocimetry (PIV) data from the experiments. As expected, turbulence model effects dominated the accuracy of the solutions with upwinding scheme selection indicating minimal effects.!

  18. Spin-mass interaction low-temperature experiment on ISS

    NASA Astrophysics Data System (ADS)

    Paik, H.; Lee, J.; Moody, M.; Strayer, D.

    The Standard Model of particle physics has had spectacular success in explaining all available data on the fundamental constituents of matter. However, one of the most important unresolved issues is the "strong CP problem." Peccei and Quinn developed a very plausible explanation for this phenom n o n over two decades agoe leading to the prediction of a new particle, dubbed the "axion," which, among other properties, mediates a force between intrinsic spin and mass. The axion is also a strong candidate for dark matter. The Spin-Mass Interaction Low-temperature Experiment (SMILE) is an ISS experiment capable of approaching, to within a factor of 100, the spin-mass interaction allowed for the axion. To reach this sensitivity, existing superconducting accelerometer technology will be combined with advantages of the low-g environment of space. An apparatus for a ground test has been designed and constructed. A slightly modified instrument, flown in LTMPF on ISS, will improve the limit of spin-mass interaction by over eight orders of magnitude from the existing limit. Although the possible detection of the axion at the level allowed may take an experiment on a quieter free-flyer, SMILE will search for a spin-coupling force in a large, explored parameter space, providing an important new test of General Relativity. SMILE employs a superconducting differential angular accelerator. To achieve the required sensitivity, the intrinsic noise of this instrument, as well as its isolation from vibrational, gravitational, and electromagnetic disturbances, must be optimized. The Brownian motion provides the ultimate limit of sensitivity for a gravity experiment. To reduce this noise, the damping coefficient of the detector, as well as its temperature, must be minimized. The low-g environment of space permits nearly free suspension of the test masses, under which the highest resonance quality factors can be attained. The amplifier noise is suppressed by driving the source at the res

  19. C-SIDE: The control-structure interaction demonstration experiment

    NASA Technical Reports Server (NTRS)

    Mohl, James B.; Davis, Hugh W.

    1993-01-01

    The Control-Structure Interaction Demonstration Experiment (C-SIDE) is sponsored by the Electro-Optics and Cryogenics Division of Ball Aerospace Systems Group. Our objective is to demonstrate methods of solution to structure control problems utilizing currently available hardware in a system that is an extension of our corporate experience. The larger space structures with which Ball has been associated are the SEASAT radar antenna, Shuttle Imaging Radar (SIR) -A, -B and -C antennas and the Radarsat spacecraft. The motivation for the C-SIDE configuration is to show that integration of active figure control in the radar's system-level design can relieve antenna mechanical design constraints. This presentation is primarily an introduction to the C-SIDE testbed. Its physical and functional layouts, and major components are described. The sensor is of special interest as it enables direct surface figure measurements from a remote location. The Remote Attitude Measurement System (RAMS) makes high-rate, unobtrusive measurements of many locations, several of which may be collocated easily with actuators. The control processor is a 386/25 executing a reduced order model-based algorithm with provision for residual mode filters to compensate for structure interaction. The actuators for the ground demonstration are non-contacting, linear force devices. Results presented illustrate some basic characteristics of control-structure interaction with this hardware. The testbed will be used for evaluation of current technologies and for research in several areas. A brief indication of the evolution of the C-SIDE is given at the conclusion.

  20. Influence of air-sea fluxes on chlorine isotopic composition of ocean water: implications for constancy in delta37Cl--a statistical inference.

    PubMed

    Shirodkar, P V; Xiao, Y K; Sarkar, A; Dalal, S G; Chivas, A R

    2006-02-01

    The behaviors of chlorine isotopes in relation to air-sea flux variables have been investigated through multivariate statistical analyses (MSA). The MSA technique provides an approach to reduce the data set and was applied to a set of 7 air-sea flux variables to supplement and describe the variation in chlorine isotopic compositions (delta37Cl) of ocean water. The variation in delta37Cl values of surface ocean water from 51 stations in 4 major world oceans--the Pacific, Atlantic, Indian and the Southern Ocean has been observed from -0.76 to +0.74 per thousand (av. 0.039+/-0.04 per thousand). The observed delta37Cl values show basic homogeneity and indicate that the air-sea fluxes act differently in different oceanic regions and help to maintain the balance between delta37Cl values of the world oceans. The study showed that it is possible to model the behavior of chlorine isotopes to the extent of 38-73% for different geographical regions. The models offered here are purely statistical in nature; however, the relationships uncovered by these models extend our understanding of the constancy in delta37Cl of ocean water in relation to air-sea flux variables. PMID:16214214

  1. Phospholipid interactions in model membrane systems. I. Experiments on monolayers.

    PubMed Central

    Mingins, J; Stigter, D; Dill, K A

    1992-01-01

    We study the lateral headgroup interactions among phosphatidylcholine (PC) molecules and among phosphatidylethanolamine (PE) molecules in monolayers and extend our previous models. In this paper, we present an extensive set of pressure-area isotherms and surface potential experiments on monolayers of phospholipids ranging from 14 to 22 carbons in length at the n-heptane/water interface, over a wide range of temperature, salt concentration, and pH on the acid side. The pressure data presented here are a considerable extension of previous data (1) to higher surface densities, comprehensively checked for monolayer loss, and include new data on PE molecules. We explore surface densities ranging from extremely low to intermediate, near to the main phase transition, in which range the surface pressures and potentials are found to be independent of the chain length. Thus, these data bear directly on the headgroup interactions. These interactions are observed to be independent of ionic strength. PC and PE molecules differ strongly in two respects: (a) the lateral repulsion among PC molecules is much stronger than for PE, and (b) the lateral repulsion among PC molecules increases strongly with temperature whereas PE interactions are almost independent of temperature. Similarly, the surface potential for PC is found to increase with temperature whereas for PE it does not. In this and the following paper we show that these data from dilute to semidilute monolayers are consistent with a theoretical model that predicts that, independent of coverage, for PC the P-N+ dipole is oriented slightly into the oil phase because of the hydrophobicity of the methyl groups, increasingly so with temperature, whereas for PE the P-N+ dipole is directed into the water phase. PMID:1617140

  2. Neutron interactions in the CUORE neutrinoless double beta decay experiment

    NASA Astrophysics Data System (ADS)

    Dolinski, Michelle Jean

    Neutrinoless double beta decay (0nuDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0nuDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0nuDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0nuDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0nuDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0nuDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0nuDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, winch can be produced underground both by (alpha,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE data to set an upper

  3. Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

    SciTech Connect

    Dolinski, Michelle Jean

    2008-10-01

    Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0vDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by (α,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE

  4. Laser plasma interaction experiments in the context of inertial fusion

    NASA Astrophysics Data System (ADS)

    Labaune, C.; Bandulet, H.; Depierreux, S.; Lewis, K.; Michel, P.; Michard, A.; Baldis, H. A.; Hulin, S.; Pesme, D.; Hüller, S.; Tikhonchuk, V.; Riconda, C.; Weber, S.

    2004-12-01

    In laser fusion, the coupling and the propagation of the laser beams in the plasma surrounding the pellet must be well controlled for to succeed in producing a high energy level. To achieve thermonuclear ignition and high gain, the coupling efficiency must be as high as possible, the uniformity of the energy deposition must be very good and the fast electron generation must be minimized. This implies a deep understanding of the laser plasma interaction mechanisms to keep the nonlinear processes at a low level. Important advances in laser plasma interaction physics have been achieved thanks to the converging efforts of the experimental and theoretical approaches. Among the different studies of the last few years, we will report results on three themes which are important for future fusion experiments. The first concerns the ability of plasmas to induce temporal and spatial incoherence to the laser beams during their propagation. Beam smoothing, beam spraying and increased incoherence may in turn reduce the level of backscattering instabilities. In laser fusion, multiple beams are used to irradiate the target. The effect of the overlap of the laser beams on parametric instabilities may complicate the problem. Not only is there the interplay between instabilities driven by one beam, but also the interplay between instabilities driven by different beams. In the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) experiment, although the overall stimulated Brillouin scattering (SBS) reflectivity was reduced, a well-defined resonance of the amplitude of ion acoustic waves (IAWs) associated with SBS has been observed for waves propagating along the bisecting direction between two laser beams. Energy transfer between two identical laser beams has been observed and correlated with plasma induced incoherence. The nonlinear saturation of stimulated scattering instabilities is a fundamental ingredient of the understanding of the observed and future reflectivity levels

  5. A Virtual Rock Physics Laboratory Through Visualized and Interactive Experiments

    NASA Astrophysics Data System (ADS)

    Vanorio, T.; Di Bonito, C.; Clark, A. C.

    2014-12-01

    As new scientific challenges demand more comprehensive and multidisciplinary investigations, laboratory experiments are not expected to become simpler and/or faster. Experimental investigation is an indispensable element of scientific inquiry and must play a central role in the way current and future generations of scientist make decisions. To turn the complexity of laboratory work (and that of rocks!) into dexterity, engagement, and expanded learning opportunities, we are building an interactive, virtual laboratory reproducing in form and function the Stanford Rock Physics Laboratory, at Stanford University. The objective is to combine lectures on laboratory techniques and an online repository of visualized experiments consisting of interactive, 3-D renderings of equipment used to measure properties central to the study of rock physics (e.g., how to saturate rocks, how to measure porosity, permeability, and elastic wave velocity). We use a game creation system together with 3-D computer graphics, and a narrative voice to guide the user through the different phases of the experimental protocol. The main advantage gained in employing computer graphics over video footage is that students can virtually open the instrument, single out its components, and assemble it. Most importantly, it helps describe the processes occurring within the rock. These latter cannot be tracked while simply recording the physical experiment, but computer animation can efficiently illustrate what happens inside rock samples (e.g., describing acoustic waves, and/or fluid flow through a porous rock under pressure within an opaque core-holder - Figure 1). The repository of visualized experiments will complement lectures on laboratory techniques and constitute an on-line course offered through the EdX platform at Stanford. This will provide a virtual laboratory for anyone, anywhere to facilitate teaching/learning of introductory laboratory classes in Geophysics and expand the number of courses

  6. Plasma interaction experiment 2 (PIX 2): Laboratory and flight results

    NASA Technical Reports Server (NTRS)

    Grier, N. T.

    1985-01-01

    The Plasma Interaction Experiments 1 and 2 (PIX 1 and 2) were designed as first steps toward understanding interactions between high-voltage solar arrays and the surrounding plasma. The PIX 2 consisted of an approximately 2000-sq cm array divided into four equal segments. Each of the segments could be biased independently and the current measured separately. In addition to the solar array segments, PIX 2 had a hot-wire-filament electron emitter and a spherical Langmuir probe. The emitter was operated when the array segments were biased positively bove 125 V. Thermal electrons from the emitter aided in balancing the electron currents collected by the array. Laboratory and flight results of PIX 2 are presented. At high positive voltages on the solar array segments, the flight currents were approximately an order of magnitude larger than the ground test currents. This is attributed to the tank walls in the laboratory interfering with the electron currents to the array segments. From previous tests it is known that the tank walls limit the electron currents at high voltages. This was the first verification of the extent of the laboratory tank effect on the plasma coupling current.

  7. Degeneracies in long-baseline neutrino experiments from nonstandard interactions

    NASA Astrophysics Data System (ADS)

    Liao, Jiajun; Marfatia, Danny; Whisnant, Kerry

    2016-05-01

    We study parameter degeneracies that can occur in long-baseline neutrino appearance experiments due to nonstandard interactions (NSI) in neutrino propagation. For a single off-diagonal NSI parameter, and neutrino and antineutrino measurements at a single L /E , there exists a continuous four-fold degeneracy (related to the mass hierarchy and θ23 octant) that renders the mass hierarchy, octant, and C P phase unknowable. Even with a combination of NO ν A and T2K data, which in principle can resolve the degeneracy, both NSI and the C P phase remain unconstrained because of experimental uncertainties. A wide-band beam experiment like DUNE will resolve this degeneracy if the nonzero off-diagonal NSI parameter is ɛe μ. If ɛe τ is nonzero, or the diagonal NSI parameter ɛe e is O (1 ), a wrong determination of the mass hierarchy and of C P violation can occur at DUNE. The octant degeneracy can be further complicated by ɛe τ, but is not affected by ɛe e.

  8. Surface erosion studies in a plasma-propellant interaction experiment

    SciTech Connect

    Bourham, M.A.; Gilligan, J.G.; Edwards, C.M.; Nahm, M.L.

    1994-12-31

    Efforts in plasma-chemical launchers are of growing interest for hypersonic mass acceleration technology. Energy transfer and mixing processes in plasma-propellant reactions are complex. The key to successful operation of electrothermal-chemical launchers (ETC) is to enhance and control the burn rate through plasma injection into the propellant. The injected plasma, as an external heat source, is usually produced from an electrothermal source ET plasma. Critical components of ETC launchers are subject to heat fluxes produced by the ET source and the additional heat generated during the combustion of the propellant. A plasma-propellant interaction experiment, PIPE, has been operated to explore the erosion behavior of candidate barrel materials under typical ETC combustion environment. The electrothermal plasma source injects a high density, low temperature plasma into a solid propellant that is followed by a material test stand. The burn rate of the propellant is calculated for each shot and the material erosion is evaluated via weight loss. The chamber pressure, discharge current and voltage, and temperature increase of the material are measured for each shot. Various coated material surfaces have been tested. Experiments were conducted on two samples of each coating, with and without propellant.

  9. Air-sea interaction during an extreme cold air outbreak from the eastern coast of the United States

    NASA Technical Reports Server (NTRS)

    Grossman, Robert L.; Betts, Alan K.

    1990-01-01

    An aircraft investigation of boundary layer mean and turbulent structure is reported, and the Lagrangian budgets of temperature and moisture in the subcloud layer following a streamline during an extreme cold air outbreak are evaluated. The maximum sea-air temperature difference was 23 K. Two aircraft were used: the NCAR Electra, which measured turbulent fluxes and investigated subcloud layer conditions, and the NASA Electra, which measured the height of cloud tops using lidar. A stratocumulus overcast was found from about 60 km offshore to the Gulf Stream core with cloud top rising downstream. East of the Gulf Stream cumulus congestus and snow showers were observed. Cloud base decreased downstream and numerous steam plumes filled the subcloud layer. Temperature cross sections show most warming, and moistening of the subcloud layer occurred before the Gulf Stream core. Windspeeds increased downstream and maxima were observed near cloud top (inversion) and in the subcloud layer. Lagrangian budgets showed most warming, and moistening of the layer between 70 m and about 100 m below mean cloud base was due to turbulent flux divergence.

  10. Study of air-sea interaction processes over the Arabian Sea and the Bay of Bengal using satellite data

    SciTech Connect

    Gautam, N.; Simon, B.; Pandey, P.C.

    1995-12-01

    The main objective of this work is to study the latitudinal and seasonal variation of latent heat fluxes (LHF) and associated atmospheric and oceanic parameters over the Arabian Sea (AS) and the Bay of Bengal (BB) for the year 1988. A significant latitudinal variation is observed in LHF for most of the months over the AS and the BB, while other oceanic and atmospheric parameters are characterized by a strong latitudinal variation in nonmonsoon months. Seasonal variations in LHF are more significant at higher latitudes compared to lower latitudes over the AS and the BB. The effect of coastal upwelling near the Somali coast decreases LHF, while surface winds near the Indian coast during monsoon months increases LHF. A comparative study over the AS and the BB demonstrates higher PW and SST over the BB than over the AS. LHF is found to be greater over the AS than over the BB for nonmonsoon months. Correlation analysis indicates that LHF is found to be highly correlated with DQ (difference between the humidity at the surface and humidity near the surface) over the AS and weakly correlated over the BB during nonmonsoon months. Throughout the year, DQ is found to be a dominant factor for LHF over the AS. However, WS exercised better control over the BB in generating LHF. SST and PW are found to be highly correlated with each other over the AS (r = 0.87) and the BB (r = 0.75) for nonmonsoon months. The correlation becomes weakly negative over the AS (r = 0.15) and weak over the BB (r = 0.26) during monsoon months. Precipitable water is found to have a high correlation with WS over the AS (r = 0.72). This unique feature is revealed by SSM/I data and has not been reported earlier due to paucity of data over this region.

  11. Sea surface carbon dioxide at the Georgia time series site (2006-2007): Air-sea flux and controlling processes

    NASA Astrophysics Data System (ADS)

    Xue, Liang; Cai, Wei-Jun; Hu, Xinping; Sabine, Christopher; Jones, Stacy; Sutton, Adrienne J.; Jiang, Li-Qing; Reimer, Janet J.

    2016-01-01

    Carbon dioxide partial pressure (pCO2) in surface seawater was continuously recorded every three hours from 18 July 2006 through 31 October 2007 using a moored autonomous pCO2 (MAPCO2) system deployed on the Gray's Reef buoy off the coast of Georgia, USA. Surface water pCO2 (average 373 ± 52 μatm) showed a clear seasonal pattern, undersaturated with respect to the atmosphere in cold months and generally oversaturated in warm months. High temporal resolution observations revealed important events not captured in previous ship-based observations, such as sporadically occurring biological CO2 uptake during April-June 2007. In addition to a qualitative analysis of the primary drivers of pCO2 variability based on property regressions, we quantified contributions of temperature, air-sea exchange, mixing, and biological processes to monthly pCO2 variations using a 1-D mass budget model. Although temperature played a dominant role in the annual cycle of pCO2, river inputs especially in the wet season, biological respiration in peak summer, and biological production during April-June 2007 also substantially influenced seawater pCO2. Furthermore, sea surface pCO2 was higher in September-October 2007 than in September-October 2006, associated with increased river inputs in fall 2007. On an annual basis this site was a moderate atmospheric CO2 sink, and was autotrophic as revealed by monthly mean net community production (NCP) in the mixed layer. If the sporadic short productive events during April-May 2007 were missed by the sampling schedule, one would conclude erroneously that the site is heterotrophic. While previous ship-based pCO2 data collected around this buoy site agreed with the buoy CO2 data on seasonal scales, high resolution buoy observations revealed that the cruise-based surveys undersampled temporal variability in coastal waters, which could greatly bias the estimates of air-sea CO2 fluxes or annual NCP, and even produce contradictory results.

  12. Characteristics of easterly-induced snowfall in Yeongdong and its relationship to air-sea temperature difference

    NASA Astrophysics Data System (ADS)

    Nam, Hyoung-Gu; Kim, Byung-Gon; Han, Sang-Ok; Lee, Chulkyu; Lee, Seoung-Soo

    2014-08-01

    Characteristics of snowfall episodes have been investigated for the past ten years in order to study its association with lowlevel stability and air-sea temperature difference over the East Sea. In general, the selected snowfall episodes have similar synoptic setting such as the Siberian High extended to northern Japan along with the Low passing by the southern Korean Peninsula, eventually resulting in the easterly flow in the Yeongdong region. Especially in the heavy snowfall episodes, convective unstable layers have been identified over the East sea due to relatively warm sea surface temperature (SST) about 8˜10°C and specifically cold pool around 1˜2 km above the surface level (ASL), which can be derived from Regional Data Assimilation and Prediction System (RDAPS), but that have not been clearly exhibited in the weak snowfall episodes. The basic mechanism to initiate snowfall around Yeongdong seems to be similar to that of lake-effect snowstorms around Great Lakes in the United States (Kristovich et al., 2003). Difference of equivalent potential temperature ( θ e ) between 850 hPa and surface as well as difference between air and sea temperatures altogether gradually began to increase in the pre-snowfall period and reached their maximum values in the course of the period, whose air (850 hPa) — sea temperature difference and snowfall intensity in case of the heavy snowfall episodes are almost larger than 20°C and 6 tims greater than the weak snowfall episodes, respectively. Interestingly, snowfall appeared to begin in case of an air-sea temperature difference exceeding over 15°C. The current analysis is overall consistent with the previous finding (Lee et al., 2012) that an instabilityinduced moisture supply to the lower atmosphere from the East sea, being cooled and saturated in the lower layer, so to speak, East Sea-Effect Snowfall (SES), would make a low-level ice cloud which eventually moves inland by the easterly flow. In addition, a longlasting

  13. Designing an experiment to measure cellular interaction forces

    NASA Astrophysics Data System (ADS)

    McAlinden, Niall; Glass, David G.; Millington, Owain R.; Wright, Amanda J.

    2013-09-01

    Optical trapping is a powerful tool in Life Science research and is becoming common place in many microscopy laboratories and facilities. The force applied by the laser beam on the trapped object can be accurately determined allowing any external forces acting on the trapped object to be deduced. We aim to design a series of experiments that use an optical trap to measure and quantify the interaction force between immune cells. In order to cause minimum perturbation to the sample we plan to directly trap T cells and remove the need to introduce exogenous beads to the sample. This poses a series of challenges and raises questions that need to be answered in order to design a set of effect end-point experiments. A typical cell is large compared to the beads normally trapped and highly non-uniform - can we reliably trap such objects and prevent them from rolling and re-orientating? In this paper we show how a spatial light modulator can produce a triple-spot trap, as opposed to a single-spot trap, giving complete control over the object's orientation and preventing it from rolling due, for example, to Brownian motion. To use an optical trap as a force transducer to measure an external force you must first have a reliably calibrated system. The optical trapping force is typically measured using either the theory of equipartition and observing the Brownian motion of the trapped object or using an escape force method, e.g. the viscous drag force method. In this paper we examine the relationship between force and displacement, as well as measuring the maximum displacement from equilibrium position before an object falls out of the trap, hence determining the conditions under which the different calibration methods should be applied.

  14. Relaunch of the Interactive Plasma Physics Educational Experience (IPPEX)

    NASA Astrophysics Data System (ADS)

    Dominguez, A.; Rusaitis, L.; Zwicker, A.; Stotler, D. P.

    2015-11-01

    In the late 1990's PPPL's Science Education Department developed an innovative online site called the Interactive Plasma Physics Educational Experience (IPPEX). It featured (among other modules) two Java based applications which simulated tokamak physics: A steady state tokamak (SST) and a time dependent tokamak (TDT). The physics underlying the SST and the TDT are based on the ASPECT code which is a global power balance code developed to evaluate the performance of fusion reactor designs. We have relaunched the IPPEX site with updated modules and functionalities: The site itself is now dynamic on all platforms. The graphic design of the site has been modified to current standards. The virtual tokamak programming has been redone in Javascript, taking advantage of the speed and compactness of the code. The GUI of the tokamak has been completely redesigned, including more intuitive representations of changes in the plasma, e.g., particles moving along magnetic field lines. The use of GPU accelerated computation provides accurate and smooth visual representations of the plasma. We will present the current version of IPPEX as well near term plans of incorporating real time NSTX-U data into the simulation.

  15. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    NASA Astrophysics Data System (ADS)

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-09-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields.

  16. Simulated Interactive Research Experiments as Educational Tools for Advanced Science.

    PubMed

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  17. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    PubMed Central

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  18. Astronomy Patch Day: An Interactive Astronomy Experience for Girl Scouts

    NASA Astrophysics Data System (ADS)

    Knierman, K. A.; McCarthy, D. W.; Schutz, K.

    2005-12-01

    To help encourage a new generation of women in science, we have created Astronomy Patch Day for the Sahuaro Girl Scout Council in Tucson, Arizona. This all-day event is an interactive experience for Girl Scouts ages 5-18 to learn about astronomical concepts and women in astronomy. Our first Astronomy Patch Day, held on March 19, 2005, in conjunction with the Sahuaro Council's annual Science, Math, and Related Technologies (SMART) program, was very successful, reaching about 150-200 girls and their leaders. Individual troops rotated every half hour among our six activity booths: Earth-Moon, Solar System, Stars, Galaxies, Universe, and Ask an Astronomer, which were staffed by trained Girl Scout Leaders as well as faculty, post-doctoral researchers, and graduate students from Steward Observatory. To earn a patch, younger girls (ages 5-12) had to complete activities at three booths and older girls had to complete all six activities. Positive feedback for this event was received from both the girls and leaders. We plan to hold Astronomy Patch Day annually, possibly with different and/or additional activities in future years. K. Knierman is supported by an Arizona/NASA Space Grant Fellowship. This outreach program is supported by NIRCam/JWST E/PO.

  19. Modeling ultrafast shadowgraphy in laser-plasma interaction experiments

    NASA Astrophysics Data System (ADS)

    Siminos, E.; Skupin, S.; Sävert, A.; Cole, J. M.; Mangles, S. P. D.; Kaluza, M. C.

    2016-06-01

    Ultrafast shadowgraphy is a new experimental technique that uses few-cycle laser pulses to image density gradients in a rapidly evolving plasma. It enables structures that move at speeds close to the speed of light, such as laser driven wakes, to be visualized. Here we study the process of shadowgraphic image formation during the propagation of a few cycle probe pulse transversely through a laser-driven wake using three-dimensional particle-in-cell simulations. In order to construct synthetic shadowgrams a near-field snapshot of the ultrashort probe pulse is analyzed by means of Fourier optics, taking into account the effect of a typical imaging setup. By comparing synthetic and experimental shadowgrams we show that the generation of synthetic data is crucial for the correct interpretation of experiments. Moreover, we study the dependence of synthetic shadowgrams on various parameters such as the imaging system aperture, the position of the object plane and the probe pulse delay, duration and wavelength. Finally, we show that time-dependent information from the interaction can be recovered from a single shot by using a broadband, chirped probe pulse and subsequent spectral filtering.

  20. Bidirectional air-sea exchange and accumulation of POPs (PAHs, PCBs, OCPs and PBDEs) in the nocturnal marine boundary layer

    NASA Astrophysics Data System (ADS)

    Lammel, Gerhard; Meixner, Franz X.; Vrana, Branislav; Efstathiou, Christos I.; Kohoutek, Jiři; Kukučka, Petr; Mulder, Marie D.; Přibylová, Petra; Prokeš, Roman; Rusina, Tatsiana P.; Song, Guo-Zheng; Tsapakis, Manolis

    2016-05-01

    As a consequence of long-range transported pollution, air-sea exchange can become a major source of persistent organic pollutants in remote marine environments. The vertical gradients in the air were quantified for 14 species, i.e. four parent polycyclic aromatic hydrocarbons (PAHs), three polychlorinated biphenyls (PCBs), three organochlorine pesticides (OCPs) and two polybrominated diphenylethers (PBDEs) in the gas-phase at a remote coastal site in the southern Aegean Sea in summer. Most vertical gradients were positive (Δc/Δz > 0), indicating downward (net depositional) flux. Significant upward (net volatilisational) fluxes were found for three PAHs, mostly during daytime, and for two OCPs, mostly during night-time, as well as for one PCB and one PBDE during part of the measurements. While phenanthrene was deposited, fluoranthene (FLT) and pyrene (PYR) seem to undergo flux oscillation, hereby not following a day-night cycle. Box modelling confirms that volatilisation from the sea surface has significantly contributed to the night-time maxima of OCPs. Fluxes were quantified based on eddy covariance. Deposition fluxes ranged from -28.5 to +1.8 µg m-2 day-1 for PAHs and -3.4 to +0.9 µg m-2 day-1 for halogenated compounds. Dry particle deposition of FLT and PYR did not contribute significantly to the vertical flux.

  1. Connections Between the Spring Breakup of the Southern Hemisphere Polar Vortex, Stationary Waves, and Air-sea Roughness

    NASA Technical Reports Server (NTRS)

    Garfinkel, Chaim I.; Oman, Luke David; Barnes, Elizabeth A.; Waugh, Darryn W.; Hurwitz, Margaret H.; Molod, Andrea M.

    2013-01-01

    A robust connection between the drag on surface-layer winds and the stratospheric circulation is demonstrated in NASA's Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). Specifically, an updated parameterization of roughness at the air-sea interface, in which surface roughness is increased for moderate wind speeds (4ms to 20ms), leads to a decrease in model biases in Southern Hemispheric ozone, polar cap temperature, stationary wave heat flux, and springtime vortex breakup. A dynamical mechanism is proposed whereby increased surface roughness leads to improved stationary waves. Increased surface roughness leads to anomalous eddy momentum flux convergence primarily in the Indian Ocean sector (where eddies are strongest climatologically) in September and October. The localization of the eddy momentum flux convergence anomaly in the Indian Ocean sector leads to a zonally asymmetric reduction in zonal wind and, by geostrophy, to a wavenumber-1 stationary wave pattern. This tropospheric stationary wave pattern leads to enhanced upwards wave activity entering the stratosphere. The net effect is an improved Southern Hemisphere vortex: the vortex breaks up earlier in spring (i.e., the spring late-breakup bias is partially ameliorated) yet is no weaker in mid-winter. More than half of the stratospheric biases appear to be related to the surface wind speed biases. As many other chemistry climate models use a similar scheme for their surface layer momentum exchange and have similar biases in the stratosphere, we expect that results from GEOSCCM may be relevant for other climate models.

  2. Comparisons of Ship-based Observations of Air-Sea Energy Budgets with Gridded Flux Products

    NASA Astrophysics Data System (ADS)

    Fairall, C. W.; Blomquist, B.

    2015-12-01

    Air-surface interactions are characterized directly by the fluxes of momentum, heat, moisture, trace gases, and particles near the interface. In the last 20 years advances in observation technologies have greatly expanded the database of high-quality direct (covariance) turbulent flux and irradiance observations from research vessels. In this paper, we will summarize observations from the NOAA sea-going flux system from participation in various field programs executed since 1999 and discuss comparisons with several gridded flux products. We will focus on comparisons of turbulent heat fluxes and solar and IR radiative fluxes. The comparisons are done for observing programs in the equatorial Pacific and Indian Oceans and SE subtropical Pacific.

  3. Influence and impact of the parametrization of the turbulent air-sea fluxes on atmospheric moisture and convection in the tropics

    NASA Astrophysics Data System (ADS)

    Torres, Olivier; Braconnot, Pascale; Gainusa-Bogdan, Alina; Hourdin, Frédéric; Marti, Olivier; Pelletier, Charles

    2016-04-01

    The turbulent fluxes across the ocean/atmosphere interface represent one of the principal driving forces of the global atmospheric and oceanic circulation and are also responsible for various phenomena like the water supply to the atmospheric column, which itself is extremely important for atmospheric convection. Although the representation of these fluxes has been the subject of major studies, it still remains a very challenging problem. Our aim is to better understand the role of these fluxes in climate change experiments and in the equator-pole redistribution of heat and water by the oceanic and atmospheric circulation. For this, we are developing a methodology starting from idealized 1D experiments and going all the way up to fully coupled ocean-atmosphere simulations of past and future climates. The poster will propose a synthesis of different simulations we have performed with a 1D version of the LMDz atmosphere model towards a first objective of understanding how different parameterizations of the turbulent fluxes affect the moisture content of the atmosphere and the feedback with the atmospheric boundary layer and convection schemes. Air-sea fluxes are not directly resolved by the models because they are subgrid-scale phenomena and are therefore represented by parametrizations. We investigate the differences between several 1D simulations of the TOGA-COARE campaign (1992-1993, Pacific warm pool region), for which 1D boundary conditions and observations are available to test the results of atmospheric models. Each simulation considers a different version of the LMDz model in terms of bulk formula (four) used to compute the turbulent fluxes. We also consider how the representation of gustiness in these parameterizations affects the results. The use of this LMDz test case (very constrained within an idealized framework) allows us to determine how the response of surface fluxes helps to reinforce or damp the atmospheric water vapor content or cloud feedbacks

  4. Social setting, intuition and experience in laboratory experiments interact to shape cooperative decision-making

    PubMed Central

    Capraro, Valerio; Cococcioni, Giorgia

    2015-01-01

    Recent studies suggest that cooperative decision-making in one-shot interactions is a history-dependent dynamic process: promoting intuition versus deliberation typically has a positive effect on cooperation (dynamism) among people living in a cooperative setting and with no previous experience in economic games on cooperation (history dependence). Here, we report on a laboratory experiment exploring how these findings transfer to a non-cooperative setting. We find two major results: (i) promoting intuition versus deliberation has no effect on cooperative behaviour among inexperienced subjects living in a non-cooperative setting; (ii) experienced subjects cooperate more than inexperienced subjects, but only under time pressure. These results suggest that cooperation is a learning process, rather than an instinctive impulse or a self-controlled choice, and that experience operates primarily via the channel of intuition. Our findings shed further light on the cognitive basis of human cooperative decision-making and provide further support for the recently proposed social heuristics hypothesis. PMID:26156762

  5. Social setting, intuition and experience in laboratory experiments interact to shape cooperative decision-making.

    PubMed

    Capraro, Valerio; Cococcioni, Giorgia

    2015-07-22

    Recent studies suggest that cooperative decision-making in one-shot interactions is a history-dependent dynamic process: promoting intuition versus deliberation typically has a positive effect on cooperation (dynamism) among people living in a cooperative setting and with no previous experience in economic games on cooperation (history dependence). Here, we report on a laboratory experiment exploring how these findings transfer to a non-cooperative setting. We find two major results: (i) promoting intuition versus deliberation has no effect on cooperative behaviour among inexperienced subjects living in a non-cooperative setting; (ii) experienced subjects cooperate more than inexperienced subjects, but only under time pressure. These results suggest that cooperation is a learning process, rather than an instinctive impulse or a self-controlled choice, and that experience operates primarily via the channel of intuition. Our findings shed further light on the cognitive basis of human cooperative decision-making and provide further support for the recently proposed social heuristics hypothesis. PMID:26156762

  6. Air-sea fluxes of CO2 and CH4 from the Penlee Point Atmospheric Observatory on the south-west coast of the UK

    NASA Astrophysics Data System (ADS)

    Yang, Mingxi; Bell, Thomas G.; Hopkins, Frances E.; Kitidis, Vassilis; Cazenave, Pierre W.; Nightingale, Philip D.; Yelland, Margaret J.; Pascal, Robin W.; Prytherch, John; Brooks, Ian M.; Smyth, Timothy J.

    2016-05-01

    We present air-sea fluxes of carbon dioxide (CO2), methane (CH4), momentum, and sensible heat measured by the eddy covariance method from the recently established Penlee Point Atmospheric Observatory (PPAO) on the south-west coast of the United Kingdom. Measurements from the south-westerly direction (open water sector) were made at three different sampling heights (approximately 15, 18, and 27 m above mean sea level, a.m.s.l.), each from a different period during 2014-2015. At sampling heights ≥ 18 m a.m.s.l., measured fluxes of momentum and sensible heat demonstrate reasonable ( ≤ ±20 % in the mean) agreement with transfer rates over the open ocean. This confirms the suitability of PPAO for air-sea exchange measurements in shelf regions. Covariance air-sea CO2 fluxes demonstrate high temporal variability. Air-to-sea transport of CO2 declined from spring to summer in both years, coinciding with the breakdown of the spring phytoplankton bloom. We report, to the best of our knowledge, the first successful eddy covariance measurements of CH4 emissions from a marine environment. Higher sea-to-air CH4 fluxes were observed during rising tides (20 ± 3; 38 ± 3; 29 ± 6 µmole m-2 d-1 at 15, 18, 27 m a.m.s.l.) than during falling tides (14 ± 2; 22 ± 2; 21 ± 5 µmole m-2 d-1), consistent with an elevated CH4 source from an estuarine outflow driven by local tidal circulation. These fluxes are a few times higher than the predicted CH4 emissions over the open ocean and are significantly lower than estimates from other aquatic CH4 hotspots (e.g. polar regions, freshwater). Finally, we found the detection limit of the air-sea CH4 flux by eddy covariance to be 20 µmole m-2 d-1 over hourly timescales (4 µmole m-2 d-1 over 24 h).

  7. Air-sea Exchange of Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Biphenyls (PCBs), Organochlorine Pesticides (OCPs) and Polybrominated Diphenyl Ethers (PBDEs) in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Lammel, G. P.; Heil, A.; Kukucka, P.; Meixner, F. X.; Mulder, M. D.; Prybilova, P.; Prokes, R.; Rusina, T. S.; Song, G. Z.; Vrana, B.

    2015-12-01

    The marine atmospheric environment is a receptor for persistent organic pollutants (POPs) which are advected from sources on land, primary, such as biomass burning by-products (PAHs, dioxins), and secondary, such as volatilization from contaminated soils (PCBs, pesticides). Primary sources do not exist in the marine environment, except for PAHs (ship engines) but following previous atmospheric deposition, the sea surface may turn to a secondary source by reversal of diffusive air-sea mass exchange. No monitoring is in place. We studied the vertical fluxes of a wide range of primary and secondary emitted POPs based on measurements in air and surface seawater at a remote coastal site in the eastern Mediterranean (2012). To this end, silicon rubbers were used as passive water samplers, vertical concentration gradients were determined in air and fluxes were quantified based on Eddy covariance. Diffusive air-sea exchange fluxes of hexachlorocyclohexanes (HCHs) and semivolatile PAHs were found close to phase equilibrium, except one PAH, retene, a wood burning tracer, was found seasonally net-volatilisational. Some PCBs, p,p'-DDE, penta- and hexachlorobenzene (PeCB, HCB) were mostly net-depositional, while PBDEs were net-volatilizational. Fluxes determined at a a remote coastal site ranged -33 - +2.4 µg m-2 d-1 for PAHs and -4.0 - +0.3 µg m-2 d-1for halogenated compounds (< 0 means net-deposition, > 0 means net-volatilization). It is concluded that nowadays in open seas more pollutants are undergoing reversal of the direction of air-sea exchange. Recgional fire activity records in combination with box model simulations suggest that deposition of retene during summer is followed by a reversal of air-sea exchange. The seawater surface as secondary source of pollution should be assessed based on flux measurements across seasons and over longer time periods.

  8. Bora event variability and the role of air-sea feedback

    USGS Publications Warehouse

    Pullen, J.; Doyle, J.D.; Haack, T.; Dorman, C.; Signell, R.P.; Lee, C.M.

    2007-01-01

    A two-way interacting high resolution numerical simulation of the Adriatic Sea using the Navy Coastal Ocean Model (NCOM) and Coupled Ocean/ Atmosphere Mesoscale Prediction System (COAMPS??) was conducted to improve forecast momentum and heat flux fields, and to evaluate surface flux field differences for two consecutive bora events during February 2003. (COAMPS?? is a registered trademark of the Naval Research Laboratory.) The strength, mean positions and extensions of the bora jets, and the atmospheric conditions driving them varied considerably between the two events. Bora 1 had 62% stronger heat flux and 51% larger momentum flux than bora 2. The latter displayed much greater diurnal variability characterized by inertial oscillations and the early morning strengthening of a west Adriatic barrier jet, beneath which a stronger west Adriatic ocean current developed. Elsewhere, surface ocean current differences between the two events were directly related to differences in wind stress curl generated by the position and strength of the individual bora jets. The mean heat flux bias was reduced by 72%, and heat flux RMSE reduced by 30% on average at four instrumented over-water sites in the two-way coupled simulation relative to the uncoupled control. Largest reductions in wind stress were found in the bora jets, while the biggest reductions in heat flux were found along the north and west coasts of the Adriatic. In bora 2, SST gradients impacted the wind stress curl along the north and west coasts, and in bora 1 wind stress curl was sensitive to the Istrian front position and strength. The two-way coupled simulation produced diminished surface current speeds of ???12% over the northern Adriatic during both bora compared with a one-way coupled simulation. Copyright 2007 by the American Geophysical Union.

  9. The Aeroclipper: A new instrument for quasi-Lagrangian measurements at the air-sea interface

    NASA Astrophysics Data System (ADS)

    Duvel, J. P.; Reverdin, G.; Pichon, T.; Vargas, A.

    The Aeroclipper is a new balloon developed by CNES. The Aeroclipper is a balloon equipped with a cable extended by a guide-rope in contact with the surface of the ocean. The balloon is vertically stabilised at a given height (currently 40 to 60m above the sea surface) and move on quasi-Lagrangian trajectories depending on the surface wind. LMD (Laboratoire de Méteorologie Dynamique), LodyC (Laboratoire d'océanographie physique et de Climatologie) and ENSTA (Ecole Nationale Supérieure de Techniques Avancées) developed an instrumentation adapted to this new measurement system. This instrumentation is distributed on one atmospheric gondola and one oceanic gondola. The aim is to measure surface physical parameters (Air and sea surface temperatures, sea surface salinity, wind, pressure and humidity) and to derive turbulent fluxes of moisture, heat and momentum. The Aeroclippers will give legs of the different parameters at a relatively high spatial resolution and thus information on the perturbation of these parameters at mesoscale. A first test of the full system will be performed from Banyuls (France) during spring 2004. The first scientific use of the Aeroclipper is planned in February 2005 in the Indian Ocean South of the Equator in link with the pilot phase of the Vasco (Variability of the Atmosphere at the intra-Seasonal time scale and Coupling with the Ocean) experiment.

  10. Measuring air-sea gas exchange velocities in a large scale annular wind-wave tank

    NASA Astrophysics Data System (ADS)

    Mesarchaki, E.; Kräuter, C.; Krall, K. E.; Bopp, M.; Helleis, F.; Williams, J.; Jähne, B.

    2014-06-01

    In this study we present gas exchange measurements conducted in a large scale wind-wave tank. Fourteen chemical species spanning a wide range of solubility (dimensionless solubility, α = 0.4 to 5470) and diffusivity (Schmidt number in water, Scw = 594 to 1194) were examined under various turbulent (u10 = 0.8 to 15 m s-1 conditions. Additional experiments were performed under different surfactant modulated (two different concentration levels of Triton X-100) surface states. This paper details the complete methodology, experimental procedure and instrumentation used to derive the total transfer velocity for all examined tracers. The results presented here demonstrate the efficacy of the proposed method, and the derived gas exchange velocities are shown to be comparable to previous investigations. The gas transfer behaviour is exemplified by contrasting two species at the two solubility extremes, namely nitrous oxide (N2O) and methanol (CH3OH). Interestingly, a strong transfer velocity reduction (up to a factor of three) was observed for N2O under a surfactant covered water surface. In contrast, the surfactant affected CH3OH, the high solubility tracer only weakly.

  11. Air-sea dimethylsulfide (DMS) gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

    NASA Astrophysics Data System (ADS)

    Bell, T. G.; De Bruyn, W.; Miller, S. D.; Ward, B.; Christensen, K.; Saltzman, E. S.

    2013-11-01

    Shipboard measurements of eddy covariance dimethylsulfide (DMS) air-sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s-1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air-sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air-sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

  12. Quantifying human subjective experience and social interaction using the eXperience Induction Machine.

    PubMed

    Bernardet, Ulysses; Väljamäe, Aleksander; Inderbitzin, Martin; Wierenga, Sytse; Mura, Anna; Verschure, Paul F M J

    2011-06-30

    With the advance of novel brain imaging technology more correlations between complex human properties and the neuronal substrate can be assessed. However, thus far, not many well-validated paradigms exist that would allow for a systematic and quantitative exploration of these phenomena. For instance, despite the rapid technological advances in the domain of mixed and virtual reality systems, a fundamental issue remains how we can define and quantify "presence". A standard approach has been to use questionnaires and self-report measures. However, it has been well established that humans' capabilities to access and externalize their internal states are limited. Hence, we have investigated the question whether other less subjective measures can be devised that can corroborate subjective self-reports on presence. In particular, we have developed a quantitative recollection task that assesses the ability of human subjects (N=40) to recollect the factual structure and organization of a structured and fully controlled experience in a human accessible mixed reality space, the eXperience Induction Machine (XIM). In this structured experience - referred to as the "Autodemo"--a virtual guide explains the key elements and properties of XIM while the user is able to freely move around in the space. To evaluate the users' experience and the amount of factual information retained about the Autodemo, we used the ITC-SOPI questionnaire and a recall test specifically designed for the Autodemo. We found significant correlations between spatial presence and engagement factors of ITC-SOPI and recall performance. Moreover we observed an interaction with the participants' gender. Our results show that we can assess correlates of "presence" by focusing on other dependent measures such as those related to memory and performance. Additionally, our work exemplifies how virtual and mixed reality systems provide new ways to address fundamental questions in psychology and cognitive neuroscience

  13. Regional coupled ocean-atmosphere downscaling in the Southeast Pacific: impacts on upwelling, mesoscale air-sea fluxes, and ocean eddies

    NASA Astrophysics Data System (ADS)

    Putrasahan, Dian A.; Miller, Arthur J.; Seo, Hyodae

    2013-05-01

    Ocean-atmosphere coupling in the Humboldt Current System (HCS) of the Southeast Pacific is studied using the Scripps Coupled Ocean-atmosphere Regional (SCOAR) model, which is used to downscale the National Center for Environmental Prediction (NCEP) Reanalysis-2 (RA2) product for the period 2000-2007 at 20-km resolution. An interactive 2-D spatial smoother within the sea-surface temperature (SST)-flux coupler is invoked in a separate run to isolate the impact of the mesoscale (˜50-200 km, in the oceanic sense) SST field felt by the atmosphere in the fully coupled run. For the HCS, SCOAR produces seasonal wind stress and wind stress curl patterns that agree better with QuikSCAT winds than those from RA2. The SCOAR downscaled wind stress distribution has substantially different impacts on the magnitude and structure of wind-driven upwelling processes along the coast compared to RA2. Along coastal locations such as Arica and Taltal, SCOAR and RA2 produce seasonally opposite signs in the total wind-driven upwelling transport. At San Juan, SCOAR shows that upwelling is mainly due to coastal Ekman upwelling transport, while in RA2 upwelling is mostly attributed to Ekman pumping. Fully coupled SCOAR shows significant SST-wind stress coupling during fall and winter, while smoothed SCOAR shows insignificant coupling throughout, indicating the important role of ocean mesoscale eddies on air-sea coupling in HCS. Coupling between SST, wind speed, and latent heat flux is incoherent in large-scale coupling and full coupling mode. In contrast, coupling between these three variables is clearly identified for oceanic mesoscales, which suggests that mesoscale SST affects latent heat directly through the bulk formulation, as well as indirectly through stability changes on the overlying atmosphere, which affects surface wind speeds. The SST-wind stress and SST-heat-flux couplings, however, fail to produce a strong change in the ocean eddy statistics. No rectified effects of ocean

  14. Hey! I Can Read This! The Interactive Book Experience.

    ERIC Educational Resources Information Center

    Butt, Donna Sabino; Thurman, Kathy Barlow

    This teaching resource goes beyond songs, games, and finger plays to function as a one-of-a-kind interactive book. Teachers are given basic instructions on how to create a variety of different interactive books for their students to enjoy. Lists of materials needed to create each book are also included with the instructions. The resource book…

  15. Interaction and e-Learning: The Student Experience

    ERIC Educational Resources Information Center

    Thorpe, Mary; Godwin, Steve

    2006-01-01

    A distinction between interpersonal and content interaction was identified in the literature, and applied in research undertaken on a selection of 36 courses. These courses differed in both the kinds of interaction offered and its integration in the teaching and assessment. They included different combinations and use of conferencing, email,…

  16. An Experiment with WWW Interactive Learning in University Education.

    ERIC Educational Resources Information Center

    McIntyre, David R.; Wolff, Francis G.

    1998-01-01

    Discusses an exploration with the use of interactive learning on the Web in an Introduction to C Programming Course taught at Cleveland State University, and compares the results with the same course taught during a previous semester using no interactive Web instruction. (Author/AEF)

  17. The Relation Between Wind Speed and Air-Sea Temperature Difference in the Marine Atmospheric Boundary Layer off Northwest Europe

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.

    2014-12-01

    Wind speed and atmospheric stability have an important role in determining the turbulence in the marine atmospheric boundary layer (MABL) as well as the surface wave field. The understanding of MABL dynamics in northwest Europe is complicated by fetch effects, the proximity of coastlines, shallow topography, and larger scale circulation patterns (e.g., cold air outbreaks). Numerical models have difficulty simulating the marine atmospheric boundary layer in coastal areas and partially enclosed seas, and this is partly due to spatial resolution problems at coastlines. In these offshore environments, the boundary layer processes are often best understood directly from time series measurements from fixed platforms or buoys, in spite of potential difficulties from platform flow distortion as well as the spatial sparseness of the data sets. This contribution presents the results of time series measurements from offshore platforms in the North Sea and Norwegian Sea in terms of a summary diagnostic - wind speed versus air-sea temperature difference (U-ΔT) - with important implications for understanding atmospheric boundary layer processes. The U-ΔT diagram was introduced in earlier surveys of data from coastal (Sletringen; O.J. Andersen and J. Løvseth, J. Wind Eng. Ind. Aerodyn., 57, 97-109, 1995) and offshore (Statfjord A; K.J. Eidsvik, Boundary-Layer Meteorol., 32, 103-132, 1985) sites in northwest Europe to summarize boundary layer conditions at a given location. Additional information from a series of measurement purpose-built offshore measurement and oil/gas production platforms from the southern North Sea to the Norwegian Sea illustrates how the wind characteristics vary spatially over large distances, highlighting the influence of cold air outbreaks, in particular. The results are important for the offshore wind industry because of the way that wind turbines accrue fatigue damage in different conditions of atmospheric stability and wind speed.

  18. Why we interact: on the functional role of the striatum in the subjective experience of social interaction.

    PubMed

    Pfeiffer, Ulrich J; Schilbach, Leonhard; Timmermans, Bert; Kuzmanovic, Bojana; Georgescu, Alexandra L; Bente, Gary; Vogeley, Kai

    2014-11-01

    There is ample evidence that human primates strive for social contact and experience interactions with conspecifics as intrinsically rewarding. Focusing on gaze behavior as a crucial means of human interaction, this study employed a unique combination of neuroimaging, eye-tracking, and computer-animated virtual agents to assess the neural mechanisms underlying this component of behavior. In the interaction task, participants believed that during each interaction the agent's gaze behavior could either be controlled by another participant or by a computer program. Their task was to indicate whether they experienced a given interaction as an interaction with another human participant or the computer program based on the agent's reaction. Unbeknownst to them, the agent was always controlled by a computer to enable a systematic manipulation of gaze reactions by varying the degree to which the agent engaged in joint attention. This allowed creating a tool to distinguish neural activity underlying the subjective experience of being engaged in social and non-social interaction. In contrast to previous research, this allows measuring neural activity while participants experience active engagement in real-time social interactions. Results demonstrate that gaze-based interactions with a perceived human partner are associated with activity in the ventral striatum, a core component of reward-related neurocircuitry. In contrast, interactions with a computer-driven agent activate attention networks. Comparisons of neural activity during interaction with behaviorally naïve and explicitly cooperative partners demonstrate different temporal dynamics of the reward system and indicate that the mere experience of engagement in social interaction is sufficient to recruit this system. PMID:24996121

  19. Genesis of Atlantic Lows Experiment (GALE) - An overview

    NASA Technical Reports Server (NTRS)

    Dirks, R. A.; Kuettner, J. P.; Moore, J. A.

    1988-01-01

    The field phase of the Genesis of Atlantic Lows Experiment (GALE) was conducted from 15 January to 15 March 1986. The objectives of GALE were to study mesoscale and air-sea interaction processes in East Coast winter storms, with particular emphasis on their contributions to cyclogenesis. This project area, specail observing systems, and field operations are described. There were thirteen special observing periods during the field phase including eight cases of cyclogenesis. Meterological and oceanographic phenomena on which special observations were collected include: cyclogenesis, rainbands, cold fronts, coastal fronts, cold-air damming, jets streaks, tropopause folding, low-level jets, cold-air outbreaks, lightning and marine boundary layer interactions with Gulf Stream and mid-shelf oceanic fronts. Preliminary research findings and operational implications are presented. GALE data documents are listed. The GALE data set is open to all interested scientists.

  20. Some experiences with the viscous-inviscid interaction approach

    NASA Technical Reports Server (NTRS)

    Vandalsem, W. R.; Steger, J. L.; Rao, K. V.

    1987-01-01

    Methods for simulating compressible viscous flow using the viscid-inviscid interaction approach are described. The formulations presented range from the more familiar full-potential/boundary-layer interaction schemes to a method for coupling Euler/Navier-Stokes and boundary-layer algorithms. An effort is made to describe the advantages and disadvantages of each formulation. Sample results are presented which illustrate the applicability of the methods.

  1. On-line interactive virtual experiments on nanoscience

    NASA Astrophysics Data System (ADS)

    Kadar, Manuella; Ileana, Ioan; Hutanu, Constantin

    2009-01-01

    This paper is an overview on the next generation web which allows students to experience virtual experiments on nano science, physics devices, processes and processing equipment. Virtual reality is used to support a real university lab in which a student can experiment real lab sessions. The web material is presented in an intuitive and highly visual 3D form that is accessible to a diverse group of students. Such type of laboratory provides opportunities for professional and practical education for a wide range of users. The expensive equipment and apparatuses that build the experimental stage in a particular standard laboratory is used to create virtual educational research laboratories. Students learn how to prepare the apparatuses and facilities for the experiment. The online experiments metadata schema is the format for describing online experiments, much like the schema behind a library catalogue used to describe the books in a library. As an online experiment is a special kind of learning object, one specifies its schema as an extension to an established metadata schema for learning objects. The content of the courses, metainformation as well as readings and user data are saved on the server in a database as XML objects.

  2. Wave/current interaction model

    NASA Technical Reports Server (NTRS)

    Liu, A. K.

    1988-01-01

    The wave-current interaction for the application to remote sensing data via numerical simulations and data comparison is modelled. Using the field data of surface current shear, wind condition and ambient wave spectrum, the numerical simulations of directional wave spectrum evolution were used to interpret and to compare with the aircraft data from Radar Ocean Wave Spectrometer (ROWS) and Surface Contour Radar (SCR) across the front during Frontal Air Sea Interaction Experiment (FASINEX). The wave-ice interaction was inspired by the observation of large amplitude waves hundreds of kms inside the ice pack in the Weddell Sea, resulting in breakup of the ice pack. The developed analysis of processes includes the refraction of waves at the pack edge, the effects of pack compression on wave propagation, wave train stability and buckling stability in the ice pack. Sources of pack compression and interaction between wave momentum and pack compression are investigated. Viscous camping of propagating waves in the marginal ice zone are also studied. The analysis suggests an explanation for the change in wave dispersion observed from the ship and the sequence of processes that cause ice pack breakup, pressure ridge formation and the formation of open bands of water.

  3. Nail-like targets for laser plasma interaction experiments

    SciTech Connect

    Pasley, J; Wei, M; Shipton, E; Chen, S; Ma, T; Beg, F N; Alexander, N; Stephens, R B; MacPhee, A G; Hey, D; Pape, S L; Patel, P; Mackinnon, A J; Key, M H; Offermann, D; Link, A; Chowdhury, E; Van-Woerkom, L D; Freeman, R R

    2007-12-18

    The interaction of ultra-high power picosecond laser pulses with solid targets is of interest both for benchmarking the results of hybrid particle in cell (PIC) codes and also for applications to re-entrant cone guided fast ignition. We describe the construction of novel targets in which copper/titanium wires are formed into 'nail-like' objects by a process of melting and micromachining, so that energy can be reliably coupled to a 24 {micro}m diameter wire. An extreme-ultraviolet image of the interaction of the Titan laser with such a target is shown.

  4. Genetic Risk by Experience Interaction for Childhood Internalizing Problems: Converging Evidence across Multiple Methods

    ERIC Educational Resources Information Center

    Vendlinski, Matthew K.; Lemery-Chalfant, Kathryn; Essex, Marilyn J.; Goldsmith, H. Hill

    2011-01-01

    Background: Identifying how genetic risk interacts with experience to predict psychopathology is an important step toward understanding the etiology of mental health problems. Few studies have examined genetic risk by experience interaction (GxE) in the development of childhood psychopathology. Methods: We used both co-twin and parent mental…

  5. SAMPIE (Solar Array Module Plasma Interactions Experiment). (Videotape)

    SciTech Connect

    Not Available

    1994-02-01

    SAMPIE is an in-space technology experiment that flew on STS-62. Its intent is to investigate the potentially damaging effects of space plasma (gases) on different types, sizes, and shapes of solar cells, solar modules, and spacecraft materials.

  6. Classroom Interaction Based on Teacher Ethnicity and Experience.

    ERIC Educational Resources Information Center

    Cook, Runett H.

    A study was conducted to investigate classroom interaction between black and white teachers working with black students in New York City. The purpose was to compare black and white teachers' attitudes as they taught minority students. Also compared were conceptions of students, parents, and administrators on what constitutes a "good teacher." The…

  7. Spatial and temporal variability of air-sea CO2 exchange of alongshore waters in summer near Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Ikawa, Hiroki; Oechel, Walter C.

    2014-03-01

    Alongshore water off Barrow, Alaska is a useful area for studying the carbon cycle of the Arctic coastal sea, because the different coastal characteristics extant in the area likely represent much larger regions of the coastal water of the western Arctic Ocean. Especially noteworthy is the inflow shelf water transferred northward by the Arctic Coastal Current into the Chukchi Sea from the North Pacific and turbid water in the Elson Lagoon where a significant amount of coastal erosion has been reported along the extensive coastal line and where a part of the water from the lagoon drains into the Beaufort Sea adjacent to the Chukchi Sea. To investigate spatial and temporal variations of air-sea CO2 flux (CO2 flux) of the alongshore water, partial pressure of CO2 of surface seawater (pCO2sw) was measured in summer, 2007 and 2008, and CO2 flux was directly measured by eddy covariance at a fixed point for the Beaufort Sea in summer 2008. Measured pCO2sw in the Chukchi Sea side was the lowest in the beginning of the measurement season and increased later in the season both in 2007 and 2008. The average CO2 flux estimated based on pCO2sw in the Chukchi Sea side was -0.10 μmol m-2 s-1 (±0.1 s.d.) using the sign convention of positive fluxes into the atmosphere from the ocean. pCO2sw in the Beaufort Sea and the Elson Lagoon was relatively higher in early summer and decreased in the middle of the summer. The overall average CO2 flux was -0.07 μmol m-2 s-1 (±0.1 s.d.) for the Beaufort Sea side and -0.03 μmol m-2 s-1 (±0.07 s.d.) for the Elson Lagoon respectively, indicating a sink of CO2 despite high carbon inflows from the terrestrial margin into the Elson Lagoon. A strong sink of CO2 was often observed from the Beaufort Sea by eddy covariance in the middle of the summer. This sink activity in the middle summer in the Beaufort Sea and Elson Lagoon was likely due to biological carbon uptake as inferred by low apparent oxygen utilization and high chlorophyll

  8. Air-sea Exchange of Dimethylsulfide (DMS) - Separation of the Transfer Velocity to Buoyancy, Turbulence, and Wave Driven Components

    NASA Astrophysics Data System (ADS)

    Yang, M.; Blomquist, B.; Huebert, B. J.; Fairall, C. W.

    2009-12-01

    In the past several years, we have measured the sea-to-air flux of DMS directly with eddy covariance on five cruises in distinct oceanic environments, including the equatorial Pacific (TAO 2003), Sargasso Sea (Biocomplexity 2004), Northern Atlantic (DOGEE 2007), Southern Ocean (SO-GasEX 2008), and Peruvian/Chilean upwelling region (VOCALS-REx 2008). Normalizing DMS flux by its concurrent air-sea concentration difference gave us the transfer velocity of DMS (kDMS). Our wealth of kDMS measurements (~2000 hourly values) in very different oceans and across a wide range of wind speeds (0.5~20.5 m/s) provides an opportunity to evaluate existing parameterizations of k and quantify the importance of various controlling factors on gas exchange. Gas exchange in different wind speed regimes is driven by distinct physical mechanisms. In low winds (<4 m/s), buoyancy-driven convection results in a finite and positive kDMS. In moderate winds (4~10 m/s), turbulence from wind-stress prevails, as we found a near linear dependence of kDMS on wind speed and on friction velocity (u*). In high winds (>10 m/s), there is additional bubble-mediated exchange from wave-breaking, which depends on gas solubility (a function of temperature and to a lesser degree, salinity). When normalizing kDMS to a reference temperature of 20°C, we found the oft-used Schmidt number correction (for diffusivity) to be inadequate because it does not account for the temperature dependence in solubility. To quantify the solubility effect, we subtract the small buoyancy-driven term computed by the NOAA-COARE model 3.0a from k660 (kDMS corrected to a Schmidt number of 660). A linear fit to the residual k660 in the moderate wind regime allows us to further separate the turbulence-driven and wave-breaking components. A solubility correction is applied to the latter, which is then added back to the buoyancy and turbulence-driven terms to give k660,C. Compared to k660, k660,C shows a significant reduction in scatter

  9. Using an ensemble data set of turbulent air-sea fluxes to evaluate the IPSL climate model in tropical regions

    NASA Astrophysics Data System (ADS)

    Gainusa-Bogdan, Alina; Servonnat, Jerome; Braconnot, Pascale

    2014-05-01

    Low-latitude turbulent ocean-atmosphere fluxes play a major role in the ocean and atmosphere dynamics, heat distribution and availability for meridional transport to higher latitudes, as well as for the global freshwater cycle. Their representation in coupled ocean-atmosphere models is thus of chief importance in climate simulations. Despite numerous reports of important observational uncertainties in large-scale turbulent flux products, only few model flux evaluation studies attempt to quantify and directly consider these uncertainties. To address this problem for large-scale, climatological flux evaluation, we assemble a comprehensive database of 14 climatological surface flux products, including in situ-based, satellite, hybrid and reanalysis data sets. We develop an associated analysis protocol and use it together with this database to offer an observational ensemble approach to model flux evaluation. We use this approach to perform an evaluation of the representation of the intertropical turbulent air-sea fluxes in a suite of CMIP5 historical simulations run with different recent versions of the IPSL model. To enhance model understanding, we consider both coupled and forced atmospheric model configurations. For the same purpose, we not only analyze the surface fluxes, but also their associated meteorological state variables and inter-variable relationships. We identify an important, systematic underestimation of the near-surface wind speed and a significant exaggeration of the sea-air temperature contrast in all the IPSL model versions considered. Furthermore, the coupled model simulations develop important sea surface temperature and associated air humidity bias patterns. Counterintuitively, these biases do not systematically transfer to significant biases in the surface fluxes. This is due to a combination of compensation of effects and the large flux observational spread. Our analyses reveal several inconsistencies in inter-variable relationships between

  10. Air-sea CO2 fluxes in the East China Sea based on multiple-year underway observations

    NASA Astrophysics Data System (ADS)

    Guo, X.-H.; Zhai, W.-D.; Dai, M.-H.; Zhang, C.; Bai, Y.; Xu, Y.; Li, Q.; Wang, G.-Z.

    2015-09-01

    This study reports the most comprehensive data set thus far of surface seawater pCO2 (partial pressure of CO2) and the associated air-sea CO2 fluxes in a major ocean margin, the East China Sea (ECS), based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability in sea surface pCO2 in the ECS except in winter, when it ranged across a narrow band of 330 to 360 μatm. We categorized the ECS into five different domains featuring with different physics and biogeochemistry to better characterize the seasonality of the pCO2 dynamics and to better constrain the CO2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang-Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO2 off the Changjiang estuary was as low as < 100 μatm, while it was up to > 400 μatm in autumn. pCO2 along the Zhejiang-Fujian coast was low in spring, summer and winter (300 to 350 μatm) but was relatively high in autumn (> 350 μatm). On the northern ECS shelf, pCO2 in summer and autumn was > 340 μatm in most areas, higher than in winter and spring. On the middle and southern ECS shelf, pCO2 in summer ranged from 380 to 400 μatm, which was higher than in other seasons (< 350 μatm). The area-weighted CO2 flux on the entire ECS shelf was -10.0 ± 2.0 in winter, -11.7 ± 3.6 in spring, -3.5 ± 4.6 in summer and -2.3 ± 3.1 mmol m-2 d-1 in autumn. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation in pCO2 rather than the bulk uncertainty. Nevertheless, on an annual basis, the average CO2 influx into the entire ECS shelf was 6.9 ± 4.0 mmol m-2 d-1, about twice the global average in ocean margins.

  11. Air-sea CO2 fluxes in the East China Sea based on multiple-year underway observations

    NASA Astrophysics Data System (ADS)

    Guo, X.-H.; Zhai, W.-D.; Dai, M.-H.; Zhang, C.; Bai, Y.; Xu, Y.; Li, Q.; Wang, G.-Z.

    2015-04-01

    This study reports thus far a most comprehensive dataset of surface seawater pCO2 (partial pressure of CO2) and the associated air-sea CO2 fluxes in a major ocean margin, the East China Sea (ECS) based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability of sea surface pCO2 in the ECS except in winter when it ranged in a narrow band of 330 to 360 μatm. In this context, we categorized the ECS into five different domains featured with different physics and biogeochemistry to better characterize the seasonality of the pCO2 dynamics and to better constrain the CO2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang-Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO2 off the Changjiang estuary was as low as < 100 μatm, while it was up to > 400 μatm in fall. pCO2 along the Zhejiang-Fujian coast was low in spring, summer and winter (300 to 350 μatm) but was relatively high in fall (> 350 μatm). In the northern ECS shelf, pCO2 in summer and fall was > 340 μatm in most areas, higher than in winter and spring. In the middle and southern ECS shelf, pCO2 in summer ranged from 380 to 400 μatm, which was higher than in other seasons (< 350 μatm). The area-weighted CO2 flux in the entire ECS shelf was -10.0 ± 2.0 mmol m-2 d-1 in winter, -11.7 ± 3.6 mmol m-2 d-1 in spring, -3.5 ± 4.6 mmol m-2 d-1 in summer and -2.3 ± 3.1 mmol m-2 d-1 in fall. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation of pCO2, which differ from the spatial variance nor the bulk uncertainty. Nevertheless, on an annual basis, the average CO2 influx into the entire ECS shelf was -6.9 ± 4.0 mmol m-2 d-1, about twice the global average in ocean margins.

  12. Interannual variability of the Indian summer monsoon associated with the air-sea feedback in the northern Indian Ocean

    NASA Astrophysics Data System (ADS)

    Shukla, Ravi P.; Huang, Bohua

    2016-03-01

    Using observation-based analyses, this study identifies the leading interannual pattern of the Indian summer monsoon rainfall (ISMR) independent of ENSO and examines the potential mechanisms of its formation. For this purpose, an objective procedure is used to isolate the variability of the summer precipitation associated with the contemporary ENSO state and in previous winter-spring, which influence the Indian summer monsoon (ISM) region in opposite ways. It is shown that the leading pattern of these ENSO-related monsoon rainfall anomalies reproduces some major ISMR features and well represents its connections to the global-scale ENSO features in both lower and upper troposphere. On the other hand, the leading pattern derived from the precipitation anomalies with the ENSO component removed in the ISM and surrounding region also accounts for a substantial amount of the monsoon precipitation centered at the eastern coast of the subtropical Arabian Sea, extending into both the western Indian Ocean and the Indian subcontinent. The associated atmospheric circulation change is regional in nature, mostly confined in the lower to mid troposphere centered in the Arabian Sea, with a mild connection to an opposite tendency centered at the South China Sea. Further analyses show that this regional pattern is associated with a thermodynamic air-sea feedback during early to mid summer season. Specifically, before the monsoon onset, an anomalous atmospheric high pressure over the Arabian Sea causes excessive shortwave radiation to the sea surface and increases SST in May. The warm SST anomalies peak in June and reduce the sea level pressure. The anomalous cyclonic circulation generates regional convection and precipitation, which also induces subsidence and anticyclonic circulation over the South China Sea. The combined cyclonic-anticyclonic circulation further transport moisture from the western Pacific into the Indian Ocean and causes its convergence into the Arabian Sea. As a

  13. The air-sea equilibrium and time trend of hexachlorocyclohexanes in the Atlantic Ocean between the Arctic and Antarctica.

    PubMed

    Lakaschus, Sonke; Weber, Kurt; Wania, Frank; Bruhn, Regina; Schrems, Otto

    2002-01-15

    Hexachlorocyclohexanes (HCHs) were determined simultaneously in air and seawater during two cruises across the Atlantic Ocean between the Arctic Ocean (Ny-Alesund/ Svalbard, 79 degrees N; 12 degrees E) and the Antarctic Continent (Neumayer Station/ Ekstroem Ice Shelf, 70 degrees S; 8.2 degrees W) in 1999/ 2000. The concentrations of alpha-HCH and gamma-HCH in air and surface waters of the Arctic exceeded those in Antarctica by 1-2 orders of magnitude. The gaseous concentrations of gamma-HCH were highest above the North Sea and between 20 degrees N and 30 degrees S. Fugacity fractions were used to estimate the direction of the air-sea gas exchange. These showed for alpha-HCH thatthe measured concentrations in both phases were close to equilibrium in the North Atlantic (78 degrees N-40 degrees N), slightly undersaturated between 30 degrees N and 10 degrees S and again close to equilibrium between 20 degrees S and 50 degrees S. Y-HCH has reached phase equilibrium in the North Atlantic as alpha-HCH, but the surface waters of the tropical and southern Atlantic were strongly undersaturated with y-HCH, especially between 30 degrees N and 20 degrees S. These findings are significantly different from two earlier estimates around 1990 as a result of global emission changes within the past decade. Therefore, we investigated the time trend of the HCHs in the surface waters of the Atlantic between 50 degrees N and 60 degrees S on the basis of archived samples taken in 1987-1997 and those from 1999. A decrease of alpha-HCH by a factor of approximately 4 is observed at all sampling locations. No decrease of gamma-HCH occurred between 30 degrees N and 30 degrees S, but there was a decrease in the North Atlantic, North Sea, and in the South Atlantic south of 40 degrees S. The constant level of gamma-HCH in the tropical Atlantic confirms the conclusion that the tropical Atlantic acts as a sink for y-HCH at present time. The measured alpha-HCH seawater concentrations were compared

  14. Spatio-temporal dynamics of biogeochemical processes and air-sea CO2 fluxes in the Western English Channel based on two years of FerryBox deployment

    NASA Astrophysics Data System (ADS)

    Marrec, P.; Cariou, T.; Latimier, M.; Macé, E.; Morin, P.; Vernet, M.; Bozec, Y.

    2014-12-01

    From January 2011 to January 2013, a FerryBox system was installed on a Voluntary Observing Ship (VOS), which crossed the Western English Channel (WEC) between Roscoff (France) and Plymouth (UK) up to 3 times a day. The FerryBox continuously measured sea surface temperature (SST), sea surface salinity (SSS), dissolved oxygen (DO), fluorescence and partial pressure of CO2 (from April 2012) along the ferry track. Sensors were calibrated based on 714 bimonthly surface samplings with precisions of 0.016 for SSS, 3.3 μM for DO, 0.40 μg L- 1 for Chlorophyll-a (Chl-a) (based on fluorescence measurements) and 5.2 μatm for pCO2. Over the 2 years of deployment (900 crossings), we reported 9% of data lost due to technical issues and quality checked data was obtained to allow investigation of the dynamics of biogeochemical processes related to air-sea CO2 fluxes in the WEC. Based on this unprecedented high-frequency dataset, the physical structure of the WEC was assessed using SST anomalies and the presence of a thermal front was observed around the latitude 49.5°N, which divided the WEC in two main provinces: the seasonally stratified northern WEC (nWEC) and the all-year well-mixed southern WEC (sWEC). These hydrographical properties strongly influenced the spatial and inter-annual distributions of phytoplankton blooms, which were mainly limited by nutrients and light availability in the nWEC and the sWEC, respectively. Air-sea CO2 fluxes were also highly related to hydrographical properties of the WEC between late April and early September 2012, with the sWEC a weak source of CO2 to the atmosphere of 0.9 mmol m- 2 d- 1, whereas the nWEC acted as a sink for atmospheric CO2 of 6.9 mmol m- 2 d- 1. The study of short time-scale dynamics of air-sea CO2 fluxes revealed that an intense and short (less than 10 days) summer bloom in the nWEC contributed to 29% of the CO2 sink during the productive period, highlighting the necessity for high frequency observations in coastal

  15. Solar neutrino interactions with liquid scintillators used for double beta-decay experiments

    NASA Astrophysics Data System (ADS)

    Ejiri, Hiroyasu; Zuber, Kai

    2016-08-01

    Solar neutrinos interact within double-beta-decay (DBD) detectors and hence will contribute to backgrounds (BGs) for DBD experiments. Background contributions due to solar neutrinos are evaluated for their interactions with atomic electrons and nuclei in liquid scintillation detectors used for DBD experiments. They are shown to be serious BGs for high-sensitivity DBD experiments to search for the Majorana neutrino masses in the inverted and normal hierarchy regions.

  16. Rotor-Fuselage Interaction: Analysis and Validation with Experiment

    NASA Technical Reports Server (NTRS)

    Berry, John D.; Bettschart, Nicolas

    1997-01-01

    The problem of rotor-fuselage aerodynamic interaction has to be considered in industry applications from various aspects. First, in order to increase helicopter speed and reduce operational costs, rotorcraft tend to be more and more compact, with a main rotor closer to the fuselage surface. This creates significant perturbations both on the main rotor and on the fuselage, including steady and unsteady effects due to blade and wake passage and perturbed inflow at the rotor disk. Furthermore,the main rotor wake affects the tail boom, empennage and anti-torque system. This has important consequences for helicopter control and vibrations at low speeds and also on tail rotor acoustics (main rotor wake-tail rotor interactions). This report describes the US Army-France MOD cooperative work on this problem from both the theoretical and experimental aspects. Using experimental 3D velocity field and fuselage surface pressure measurements, three codes that model the interactions of a helicopter rotor with a fuselage are compared. These comparisons demonstrate some of the strengths and weaknesses of current models for the combined rotor-fuselage analysis.

  17. Reconstruction of super-resolution fields of ocean pCO2 and air-sea fluxes of CO2 from satellite imagery in the Southeastern Atlantic

    NASA Astrophysics Data System (ADS)

    Hernández-Carrasco, I.; Sudre, J.; Garçon, V.; Yahia, H.; Garbe, C.; Paulmier, A.; Dewitte, B.; Illig, S.; Dadou, I.

    2015-01-01

    The knowledge of Green House Gases GHGs fluxes at the air-sea interface at high resolution is crucial to accurately quantify the role of the ocean in the absorption and emission of GHGs. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO2, pCO2, and air-sea CO2 fluxes at super resolution (4 km) using Sea Surface Temperature (SST) and Ocean Colour (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution of pCO2, and air-sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the Microcanonical Multifractal Formalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multiresolution analysis performed on the signal of the so-called singularity exponents allows the correct and near optimal cross-scale inference of GHGs fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela area. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small scale variability. We examine different combinations of Ocean Colour and Sea Surface Temperature products in order to increase the number of valid points and the quality of the inferred pCO2 field. The methodology is validated using in-situ measurements by means of statistical errors. We obtain that mean absolute and relative errors in the inferred values of pCO2 with respect to in-situ measurements are smaller than for CarbonTracker.

  18. The OceanFlux Greenhouse Gases methodology for deriving a sea surface climatology of CO2 fugacity in support of air-sea gas flux studies

    NASA Astrophysics Data System (ADS)

    Goddijn-Murphy, L. M.; Woolf, D. K.; Land, P. E.; Shutler, J. D.; Donlon, C.

    2015-07-01

    Climatologies, or long-term averages, of essential climate variables are useful for evaluating models and providing a baseline for studying anomalies. The Surface Ocean CO2 Atlas (SOCAT) has made millions of global underway sea surface measurements of CO2 publicly available, all in a uniform format and presented as fugacity, fCO2. As fCO2 is highly sensitive to temperature, the measurements are only valid for the instantaneous sea surface temperature (SST) that is measured concurrently with the in-water CO2 measurement. To create a climatology of fCO2 data suitable for calculating air-sea CO2 fluxes, it is therefore desirable to calculate fCO2 valid for a more consistent and averaged SST. This paper presents the OceanFlux Greenhouse Gases methodology for creating such a climatology. We recomputed SOCAT's fCO2 values for their respective measurement month and year using monthly composite SST data on a 1° × 1° grid from satellite Earth observation and then extrapolated the resulting fCO2 values to reference year 2010. The data were then spatially interpolated onto a 1° × 1° grid of the global oceans to produce 12 monthly fCO2 distributions for 2010, including the prediction errors of fCO2 produced by the spatial interpolation technique. The partial pressure of CO2 (pCO2) is also provided for those who prefer to use pCO2. The CO2 concentration difference between ocean and atmosphere is the thermodynamic driving force of the air-sea CO2 flux, and hence the presented fCO2 distributions can be used in air-sea gas flux calculations together with climatologies of other climate variables.

  19. Response of biological production and air-sea CO2 fluxes to upwelling intensification in the California and Canary Current Systems

    NASA Astrophysics Data System (ADS)

    Lachkar, Zouhair; Gruber, Nicolas

    2013-01-01

    Upwelling-favorable winds have increased in most Eastern Boundary Upwelling Systems (EBUS) in the last decades, and it is likely that they increase further in response to global climate change. Here, we explore the response of biological production and air-sea CO2 fluxes to upwelling intensification in two of the four major EBUS, namely the California Current System (California CS) and Canary Current System (Canary CS). To this end, we use eddy-resolving regional ocean models on the basis of the Regional Oceanic Modeling System (ROMS) to which we have coupled a NPZD-type ecosystem model and a biogeochemistry module describing the carbon cycle and subject these model configurations to an idealized increase in the wind stress. We find that a doubling of the wind-stress doubles net primary production (NPP) in the southern California CS and central and northern Canary CS, while it leads to an increase of less than 50% in the central and northern California CS as well as in the southern Canary CS. This differential response is a result of i) different nutrient limitation states with higher sensitivity to upwelling intensification in regions where nutrient limitation is stronger and ii) more efficient nutrient assimilation by biology in the Canary CS relative to the California CS because of a faster nutrient-replete growth rate and longer nearshore water residence times. In the regions where production increases commensurably with upwelling intensification, the enhanced net biological uptake of CO2 compensates the increase in upwelling driven CO2 outgassing, resulting in only a small change in the biological pump efficiency and hence in a small sensitivity of air-sea CO2 fluxes to upwelling intensification. In contrast, in the central California CS as well as in the southern Canary CS around Cape Blanc, the reduced biological efficiency enhances the CO2 outgassing and leads to a substantial sensitivity of the air-sea CO2 fluxes to upwelling intensification.

  20. Reconstruction of super-resolution ocean pCO2 and air-sea fluxes of CO2 from satellite imagery in the southeastern Atlantic

    NASA Astrophysics Data System (ADS)

    Hernández-Carrasco, I.; Sudre, J.; Garçon, V.; Yahia, H.; Garbe, C.; Paulmier, A.; Dewitte, B.; Illig, S.; Dadou, I.; González-Dávila, M.; Santana-Casiano, J. M.

    2015-09-01

    An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) requires to access the high-resolution of the GHG air-sea flux at the interface. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO2 ( pCO2) and air-sea CO2 fluxes at super resolution (4 km, i.e., 1/32° at these latitudes) using sea surface temperature (SST) and ocean color (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution pCO2 and air-sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the microcanonical multifractal formalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multi-resolution analysis performed on the signal of the so-called singularity exponents allows for the correct and near optimal cross-scale inference of GHG fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela area. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small-scale variability. We examine different combinations of ocean color and sea surface temperature products in order to increase the number of valid points and the quality of the inferred pCO2 field. The methodology is validated using in situ measurements by means of statistical errors. We find that mean absolute and relative errors in the inferred values of pCO2 with respect to in situ measurements are smaller than for CarbonTracker.

  1. The carbon dioxide system on the Mississippi River-dominated continental shelf in the northern Gulf of Mexico: 1. Distribution and air-sea CO2 flux

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Jen; Cai, Wei-Jun; Wang, Yongchen; Lohrenz, Steven E.; Murrell, Michael C.

    2015-03-01

    River-dominated continental shelf environments are active sites of air-sea CO2 exchange. We conducted 13 cruises in the northern Gulf of Mexico, a region strongly influenced by fresh water and nutrients delivered from the Mississippi and Atchafalaya River system. The sea surface partial pressure of carbon dioxide (pCO2) was measured, and the air-sea CO2 flux was calculated. Results show that CO2 exchange exhibited a distinct seasonality: the study area was a net sink of atmospheric CO2 during spring and early summer, and it was neutral or a weak source of CO2 to the atmosphere during midsummer, fall, and winter. Along the salinity gradient, across the shelf, the sea surface shifted from a source of CO2 in low-salinity zones (0≤S<17) to a strong CO2 sink in the middle-to-high-salinity zones (17≤S<33), and finally was a near-neutral state in the high-salinity areas (33≤S<35) and in the open gulf (S≥35). High pCO2 values were only observed in narrow regions near freshwater sources, and the distribution of undersaturated pCO2 generally reflected the influence of freshwater inputs along the shelf. Systematic analyses of pCO2 variation demonstrated the importance of riverine nitrogen export; that is, riverine nitrogen-enhanced biological removal, along with mixing processes, dominated pCO2 variation along the salinity gradient. In addition, extreme or unusual weather events were observed to alter the alongshore pCO2 distribution and to affect regional air-sea CO2 flux estimates. Overall, the study region acted as a net CO2 sink of 0.96 ± 3.7 mol m-2 yr-1 (1.15 ± 4.4 Tg C yr-1).

  2. First Laser-Plasma Interaction and Hohlraum Experiments on NIF

    SciTech Connect

    Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; McDonald, J W; Niemann, C; Mackinnon, A J

    2005-06-17

    Recently the first hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive Inertial Confinement Fusion (ICF) designs. The effects of laser beam smoothing by spectral dispersion (SSD) and polarization smoothing (PS) on the beam propagation in long scale gas-filled pipes has been studied at plasma scales as found in indirect drive gas filled ignition hohlraum designs. The long scale gas-filled target experiments have shown propagation over 7 mm of dense plasma without filamentation and beam break up when using full laser smoothing. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment in analytical models and in LASNEX calculations has been proven for the first time. The comparison of these results with modeling will be discussed.

  3. Interest Enhancements to Science Experiments: Interactions with Student Gender.

    ERIC Educational Resources Information Center

    Martinez, Michael E.

    1992-01-01

    Summarizes comparisons of self-reported interest by gender and experimental condition for middle school students (n=101) who performed scientific experiments under conditions designed to vary across difficulty levels, social contexts, and scenarios of fantasy to realism. Findings indicate that boys were more attentive to aspects of experimental…

  4. Cross-Modal Interactions in the Experience of Musical Performances: Physiological Correlates

    ERIC Educational Resources Information Center

    Chapados, Catherine; Levitin, Daniel J.

    2008-01-01

    This experiment was conducted to investigate cross-modal interactions in the emotional experience of music listeners. Previous research showed that visual information present in a musical performance is rich in expressive content, and moderates the subjective emotional experience of a participant listening and/or observing musical stimuli [Vines,…

  5. Magnetosphere-thermosphere coupling - An experiment in interactive modeling

    NASA Technical Reports Server (NTRS)

    Forbes, Jeffrey M.; Harel, Moshe

    1989-01-01

    The present use of the Rice convection model to investigate the electrodynamic coupling of the thermosphere to the inner magnetosphere encompasses the effects of EUV-driven and convection-driven neutral winds under quasi-equilibrium conditions. Convection-driven winds are included self-consistently and interactively; a steady-state wind parameterization is written analytically in terms of the electrostatic potential, which is in turn included in a closed-loop calculation for the electric potential itself. The simulations conducted show that, as the neutral system approaches a quasi-equilibrium state, the neutral winds play a much more significant role.

  6. Primate paternal care: interactions between biology and social experience

    PubMed Central

    Storey, Anne E.; Ziegler, Toni E.

    2016-01-01

    We review recent research on the roles of hormones and social experiences on the development of paternal care in humans and non-human primates. Generally, lower concentrations of testosterone and higher concentrations of oxytocin are associated with greater paternal responsiveness. Hormonal changes prior to the birth appear to be important in preparation for fatherhood and changes after the birth are related to how much time fathers spend with offspring and whether they provide effective care. Prolactin may facilitate approach and the initiation of infant care, and in some biparental non-human primates, it affects body mass regulation. Glucocorticoids are involved in coordinating reproductive and parental behavior between mates. New research involving intranasal oxytocin and neuropeptide receptor polymorphisms may help us understand individual variation in paternal responsiveness. This area of research, integrating both biological factors and the role of early and adult experience, has the potential to suggest individually designed interventions that can strengthen relationships between fathers and their offspring. PMID:26253726

  7. Aerothermal modeling program, phase 2. Element B: Flow interaction experiment

    NASA Astrophysics Data System (ADS)

    Nikjooy, M.; Mongia, H. C.; Murthy, S. N. B.; Sullivan, J. P.

    1986-10-01

    The design process was improved and the efficiency, life, and maintenance costs of the turbine engine hot section was enhanced. Recently, there has been much emphasis on the need for improved numerical codes for the design of efficient combustors. For the development of improved computational codes, there is a need for an experimentally obtained data base to be used at test cases for the accuracy of the computations. The purpose of Element-B is to establish a benchmark quality velocity and scalar measurements of the flow interaction of circular jets with swirling flow typical of that in the dome region of annular combustor. In addition to the detailed experimental effort, extensive computations of the swirling flows are to be compared with the measurements for the purpose of assessing the accuracy of current and advanced turbulence and scalar transport models.

  8. Experiments on the interaction between hydrodynamic turbulence and surface waves

    NASA Astrophysics Data System (ADS)

    Jamin, Timothee; Berhanu, Michael; Falcon, Eric

    2014-11-01

    Different regimes of interaction between hydrodynamic turbulence and a free surface are investigated in a meter scale basin. A homogeneous and isotropic turbulence is generated by an 8×8 array of jets pointing upwards at the bottom of the tank. The 64 jets are driven individually to reach a random spatiotemporal forcing pattern and produce an intense turbulence. Using fluid velocity measurements, we characterize the turbulence obtained with this setup, then we investigate free-surface deformations induced by hydrodynamic turbulence. In a second stage an electromechanical shaker will generate gravity-capillary waves at the free surface. We aim to study reduction or amplification of surface waves and then measure energy exchange between hydrodynamic turbulence and wave turbulence. This work was supported by the DGA-CNRS Ph.D program and ANR Turbulon 12-BS04-0005.

  9. Primate paternal care: Interactions between biology and social experience.

    PubMed

    Storey, Anne E; Ziegler, Toni E

    2016-01-01

    This article is part of a Special Issue "Parental Care".We review recent research on the roles of hormones and social experiences on the development of paternal care in humans and non-human primates. Generally, lower concentrations of testosterone and higher concentrations of oxytocin are associated with greater paternal responsiveness. Hormonal changes prior to the birth appear to be important in preparation for fatherhood and changes after the birth are related to how much time fathers spend with offspring and whether they provide effective care. Prolactin may facilitate approach and the initiation of infant care, and in some biparental non-human primates, it affects body mass regulation. Glucocorticoids may be involved in coordinating reproductive and parental behavior between mates. New research involving intranasal oxytocin and neuropeptide receptor polymorphisms may help us understand individual variation in paternal responsiveness. This area of research, integrating both biological factors and the role of early and adult experience, has the potential to suggest individually designed interventions that can strengthen relationships between fathers and their partners and offspring. PMID:26253726

  10. DNA-cisplatin interaction studied with single molecule stretching experiments.

    PubMed

    Crisafuli, F A P; Cesconetto, E C; Ramos, E B; Rocha, M S

    2012-05-01

    By performing single molecule stretching experiments with optical tweezers, we have studied the changes in the mechanical properties of DNA-cisplatin complexes as a function of some variables of interest such as the drug diffusion time and concentration in the sample. We propose a model to explain the behavior of the persistence length as a function of the drug concentration, extracting the binding data from pure mechanical measurements. Such analysis has allowed us to show that cisplatin binds cooperatively to the DNA molecule. In addition, DNA compaction by the action of the drug was also observed under our experimental conditions by studying the kinetics of some mechanical properties such as the radius of gyration and the end-to-end distance, e.g. Crisafuli et al., Integr. Biol., 2011, xx, xxxx. PMID:22513758

  11. The Dynamic Reactance Interaction – How Vested Interests Affect People’s Experience, Behavior, and Cognition in Social Interactions

    PubMed Central

    Steindl, Christina; Jonas, Eva

    2015-01-01

    In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner’s freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor–client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor) or a patient (client). In both studies we incorporated a vested interest. In Study 1 (N = 82) we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N = 207) further demonstrated that doctors expressed their reactance in a subtle way: they revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically. PMID:26640444

  12. Communication and laboratory performance in parapsychology experiments: demand characteristics and the social organization of interaction.

    PubMed

    Wooffitt, Robin

    2007-09-01

    This paper reports findings from a conversation analytic study of experimenter-participant interaction in parapsychology experiments. It shows how properties of communication through which the routine business of the experiment is conducted may have an impact on the research participant's subsequent performance. In this, the study explores social psychological features of the psychology laboratory. In particular, it examines aspects of Orne's (1962) account of what he called the demand characteristics of the psychological experiment. The data come from a corpus of audio recordings of experimenter-participant interaction during experiments on extra-sensory perception. These kinds of experiments, and the phenomena they purport to study, are undoubtedly controversial; however, the paper argues that there are grounds for social psychologists to consider parapsychology experiments as a class (albeit distinctive) of psychology experiments, and, therefore, as sites in which general social psychological and communicative phenomena can be studied. The empirical sections of the paper examine interaction during part of the experimental procedure when the experimenter verbally reviews a record of the participant's imagery reported during an earlier part of the experiment. The analysis shows that the way in which the experimenter acknowledges the research participants' utterances may be significant for the trajectory of the experiment and explores how the participants' subsequent performance in the experiment may be influenced by interactionally generated contingencies. PMID:17877849

  13. Direct Measurement of Air-Sea Exchange of N2O5 and ClNO2 at a Polluted Coastal Site (Invited)

    NASA Astrophysics Data System (ADS)

    Bertram, T. H.; Kim, M.; Ryder, O. S.; Farmer, D.

    2013-12-01

    The reactive uptake of N2O5 at aqueous interfaces can serve as both an efficient NOx removal mechanism and regionally significant halogen activation process through the production of photo-labile ClNO2 molecules. Both the reaction rate and ClNO2 product yield are a complex function of the chemical composition and chloride molarity of the reactive surface. To date, analysis of the impact of N2O5 chemistry on oxidant loadings in the marine boundary layer has been limited to reactions occurring on aerosol particles, with little attention paid to reactions occurring at the air-sea interface. Here, we report the first direct measurements of the air-sea flux of N2O5 and ClNO2 made via eddy covariance in the polluted marine boundary layer in La Jolla, CA. We observe rapid N2O5 deposition to the ocean surface, while ClNO2 deposition rates were significantly lower and fastest during the first three hours following sunset. The results are interpreted using a time-dependent box-model, suggesting that under conditions characterized by shallow marine boundary layer heights (< 100 m) and representative aerosol reactive uptake coefficients (< 0.01), N2O5 deposition to the ocean surface can account for over 50% of the total N2O5 loss rate.

  14. Natural Air-Sea Flux of CO2 in Simulations of the NASA-GISS Climate Model: Sensitivity to the Physical Ocean Model Formulation

    NASA Technical Reports Server (NTRS)

    Romanou, A.; Gregg, Watson W.; Romanski, J.; Kelley, M.; Bleck, R.; Healy, R.; Nazarenko, L.; Russell, G.; Schmidt, G. A.; Sun, S.; Tausnev, N.

    2013-01-01

    Results from twin control simulations of the preindustrial CO2 gas exchange (natural flux of CO2) between the ocean and the atmosphere are presented here using the NASA-GISS climate model, in which the same atmospheric component (modelE2) is coupled to two different ocean models, the Russell ocean model and HYCOM. Both incarnations of the GISS climate model are also coupled to the same ocean biogeochemistry module (NOBM) which estimates prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2. Model intercomparison is carried out at equilibrium conditions and model differences are contrasted with biases from present day climatologies. Although the models agree on the spatial patterns of the air-sea flux of CO2, they disagree on the strength of the North Atlantic and Southern Ocean sinks mainly because of kinematic (winds) and chemistry (pCO2) differences rather than thermodynamic (SST) ones. Biology/chemistry dissimilarities in the models stem from the different parameterizations of advective and diffusive processes, such as overturning, mixing and horizontal tracer advection and to a lesser degree from parameterizations of biogeochemical processes such as gravitational settling and sinking. The global meridional overturning circulation illustrates much of the different behavior of the biological pump in the two models, together with differences in mixed layer depth which are responsible for different SST, DIC and nutrient distributions in the two models and consequently different atmospheric feedbacks (in the wind, net heat and freshwater fluxes into the ocean).

  15. Variability of 14C reservoir age and air-sea flux of CO2 in the Peru-Chile upwelling region during the past 12,000 years

    NASA Astrophysics Data System (ADS)

    Carré, Matthieu; Jackson, Donald; Maldonado, Antonio; Chase, Brian M.; Sachs, Julian P.

    2016-01-01

    The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile (~ 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air-sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air-sea carbon flux in this region.

  16. Flow interaction experiment. Volume 2: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  17. Flow interaction experiment. Volume 1: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  18. A Formative Experiment to Enhance Teacher-Child Language Interactions in a Preschool Classroom

    ERIC Educational Resources Information Center

    Bradley, Barbara A.; Reinking, David

    2011-01-01

    A formative experiment investigated how two strategies aimed at increasing the quality and quantity of language interactions could be integrated into a preschool classroom. Strategies for enriching language interactions were introduced during book sharing, semi-structured group activities, and mealtimes. Mixed methods revealed factors that…

  19. Student Perceptions of Experiences of Interaction in Online Graduate Education Course

    ERIC Educational Resources Information Center

    Pugh, Daphne

    2010-01-01

    This phenomenological study investigated student perceptions of experiences of interaction in online graduate education courses. The researcher aimed to better understand the importance of interaction to students involved with online graduate education courses. The purposive sample included fifteen graduate students who had completed at least one…

  20. Disability Support Workers' Experience of Interaction with a Person with Profound Intellectual Disability

    ERIC Educational Resources Information Center

    Forster, Sheridan; Iacono, Teresa

    2008-01-01

    Background: The primary communication partner for many people with profound intellectual disability (PID) who are living in supported accommodation is their disability support worker (DSW). The experiences of DSWs in interacting with people with PID have received limited attention in the literature. Method: The nature of interactions between…

  1. Technically Speaking: On the Structure and Experience of Interaction Involving Augmentative Alternative Communications

    ERIC Educational Resources Information Center

    Engelke, Christopher Robert

    2013-01-01

    Technically Speaking: On the Structure and Experience of Interaction Involving Augmentative Alternative Communications examines the ways that communication is structured and experienced by looking at interactions involving augmented communicators--people with severe speech disabilities who use forms of assistive technology in order to communicate…

  2. Interacting as Experimenting. The Integration of Interaction Laboratory Functions for Lecture Improvement: Four Studies.

    ERIC Educational Resources Information Center

    Klinzing, Hans Gerhard

    This paper examines four studies, integrated into regular courses for the preparation of secondary school teachers at the University of Tuebingen (Germany), that assessed the effectiveness of an interaction laboratory to enhance social competence, as well as lecturing skills. The program involved formal instruction; symbolic modeling and…

  3. Innovative Interactive Visitor Experiences Focused on Climate Change

    NASA Astrophysics Data System (ADS)

    Lettvin, E. E.

    2011-12-01

    Pacific Science Center has adopted a multi-pronged approach to introduce visitors to the concepts of climate change and linkages to human behavior in an informal science education setting. We leverage key fixed exhibit assets derived from collaborations with NOAA: Science on a Sphere and an exhibit kiosk showcasing local CO2 measurements that are adjacent on our exhibit floor. NOAA PMEL Scientists deployed a sensor at the top of the Space Needle that measures variability in atmospheric CO2 over Seattle; the kiosk showcases these near-real-time, daily, weekly and monthly measurements as well as similar observations from a NOAA buoy near Aberdeen, Washington. Displays of these data enable visitors to see first-hand varying CO2 levels in urban and remote marine environments as well as seasonal cycling. It also reveals quantifiable increases in CO2 levels over a relatively short time (~5 years). Trained interpreters help visitors understand linkages between personal behavior and corresponding CO2 footprints. Interpreters discuss connections between local and regional CO2 measurements displayed on the kiosk, and global Sphere datasets including NOAA Carbon Tracker, changing arctic sea ice coverage and sea level rise projections. Portable Discovery Carts, consisting of props and interactive, hands-on activities provide a platform for facilitated interpretation on a series of topics. We have developed two climate focused carts: 'Sinks and Sources' that examines materials and activities that produce and absorb carbon, and 'Ocean Acidification' that shows how absorption of atmospheric CO2 is changing ocean composition and its habitability for marine life. These carts can be deployed anywhere on the exhibit floor but are primarily used adjacent to the Sphere and the kiosk, making it possible to have a range of conversations about global and local CO2 levels, linkages to individual and collective behaviour and associated implications. Additional collaborations with members of

  4. Drum-mate: interaction dynamics and gestures in human-humanoid drumming experiments

    NASA Astrophysics Data System (ADS)

    Kose-Bagci, Hatice; Dautenhahn, Kerstin; Syrdal, Dag S.; Nehaniv, Chrystopher L.

    2010-06-01

    This article investigates the role of interaction kinesics in human-robot interaction (HRI). We adopted a bottom-up, synthetic approach towards interactive competencies in robots using simple, minimal computational models underlying the robot's interaction dynamics. We present two empirical, exploratory studies investigating a drumming experience with a humanoid robot (KASPAR) and a human. In the first experiment, the turn-taking behaviour of the humanoid is deterministic and the non-verbal gestures of the robot accompany its drumming to assess the impact of non-verbal gestures on the interaction. The second experiment studies a computational framework that facilitates emergent turn-taking dynamics, whereby the particular dynamics of turn-taking emerge from the social interaction between the human and the humanoid. The results from the HRI experiments are presented and analysed qualitatively (in terms of the participants' subjective experiences) and quantitatively (concerning the drumming performance of the human-robot pair). The results point out a trade-off between the subjective evaluation of the drumming experience from the perspective of the participants and the objective evaluation of the drumming performance. A certain number of gestures was preferred as a motivational factor in the interaction. The participants preferred the models underlying the robot's turn-taking which enable the robot and human to interact more and provide turn-taking closer to 'natural' human-human conversations, despite differences in objective measures of drumming behaviour. The results are consistent with the temporal behaviour matching hypothesis previously proposed in the literature which concerns the effect that the participants adapt their own interaction dynamics to the robot's.

  5. The Role of Personal Experience and Social Interaction in Knowledge Creation and Utilisation.

    ERIC Educational Resources Information Center

    Handzic, Meliha; Tolhurst, Denise

    This paper reports the results of an empirical examination of the effects of personal experience and social interaction on individual knowledge and performance in a specific decision making task context. The study revealed a differential effect of increased experience on the quality of participants decisions. In particular, increased experience…

  6. Lysozyme Thermal Denaturation and Self-Interaction: Four Integrated Thermodynamic Experiments for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Schwinefus, Jeffrey J.; Schaefle, Nathaniel J.; Muth, Gregory W.; Miessler, Gary L.; Clark, Christopher A.

    2008-01-01

    As part of an effort to infuse our physical chemistry laboratory with biologically relevant, investigative experiments, we detail four integrated thermodynamic experiments that characterize the denaturation (or unfolding) and self-interaction of hen egg white lysozyme as a function of pH and ionic strength. Students first use Protein Explorer to…

  7. Remote Manipulator System (RMS)-based Controls-Structures Interaction (CSI) flight experiment feasibility study

    NASA Technical Reports Server (NTRS)

    Demeo, Martha E.

    1990-01-01

    The feasibility of an experiment which will provide an on-orbit validation of Controls-Structures Interaction (CSI) technology, was investigated. The experiment will demonstrate the on-orbit characterization and flexible-body control of large flexible structure dynamics using the shuttle Remote Manipulator System (RMS) with an attached payload as a test article. By utilizing existing hardware as well as establishing integration, operation and safety algorithms, techniques and procedures, the experiment will minimize the costs and risks of implementing a flight experiment. The experiment will also offer spin-off enhancement to both the Shuttle RMS (SRMS) and the Space Station RMS (SSRMS).

  8. Sources of tropical Atlantic coupled model biases derived from initialised hindcasts and partially coupled sensitivity experiments

    NASA Astrophysics Data System (ADS)

    Deppenmeier, Anna-Lena; Hazeleger, Wilco; Haarsma, Rein; Prodhomme, Chloé; Exarchou, Eleftheria; Doblas-Reyes, Francisco J.

    2016-04-01

    State-of-the-art coupled general circulation models (CGCMs) still fail to simulate the mean state and variability of the tropical Atlantic (TA) climate correctly. We investigate the importance of air-sea interaction at different regions in the TA by means of performing partially coupled sensitivity experiments with the state-of-the-art CGCM EC-Earth3.1. All simulations are intialised from the observed climate state. By studying the initial drift in sensitivity experiments we obtain insight into the tropical dynamics and sources of model bias. We test the influence of realistic wind stress forcing over different regions of the TA on the development of SST as well as other oceanic biases. A series of hindcasts fully initialised in May and run until the end of August are performed with prescribed ERA-Interim zonal and meridional wind stresses over three different regions: firstly, we force the entire TA from 15N - 30S. Secondly, we force the equatorial band only between 5N - 5S, and finally we force the coastal area of the Angola Benguela upwelling region between 0W and the coast and between 5S - 30N. Our setup only affects the oceanic forcing and leaves the atmosphere free to adapt, such that we can identify the air-sea interaction processes in the different regions and their effect on the SST bias in the fully coupled system. The differences between forcing the entire TA and the equatorial region only are very small, which hints to the great importance of the relatively narrow equatorial region. The coastal upwelling area does not strongly affect the equatorial region in our model. We identify the equatorial band as most susceptible to errors in the wind stress forcing and, due to the strong atmosphere-ocean coupling, as source of the main biases in our model. The partially coupled experiments with initialised seasonal hindcasts appear to be a powerful tool to identify the sources of model biases and to identify relevant air-sea interaction processes in the TA.

  9. Dynamics of air-sea CO2 fluxes in the northwestern European shelf based on voluntary observing ship and satellite observations

    NASA Astrophysics Data System (ADS)

    Marrec, P.; Cariou, T.; Macé, E.; Morin, P.; Salt, L. A.; Vernet, M.; Taylor, B.; Paxman, K.; Bozec, Y.

    2015-09-01

    From January 2011 to December 2013, we constructed a comprehensive pCO2 data set based on voluntary observing ship (VOS) measurements in the western English Channel (WEC). We subsequently estimated surface pCO2 and air-sea CO2 fluxes in northwestern European continental shelf waters using multiple linear regressions (MLRs) from remotely sensed sea surface temperature (SST), chlorophyll a concentration (Chl a), wind speed (WND), photosynthetically active radiation (PAR) and modeled mixed layer depth (MLD). We developed specific MLRs for the seasonally stratified northern WEC (nWEC) and the permanently well-mixed southern WEC (sWEC) and calculated surface pCO2 with uncertainties of 17 and 16 μatm, respectively. We extrapolated the relationships obtained for the WEC based on the 2011-2013 data set (1) temporally over a decade and (2) spatially in the adjacent Celtic and Irish seas (CS and IS), two regions which exhibit hydrographical and biogeochemical characteristics similar to those of WEC waters. We validated these extrapolations with pCO2 data from the SOCAT and LDEO databases and obtained good agreement between modeled and observed data. On an annual scale, seasonally stratified systems acted as a sink of CO2 from the atmosphere of -0.6 ± 0.3, -0.9 ± 0.3 and -0.5 ± 0.3 mol C m-2 yr-1 in the northern Celtic Sea, southern Celtic sea and nWEC, respectively, whereas permanently well-mixed systems acted as source of CO2 to the atmosphere of 0.2 ± 0.2 and 0.3 ± 0.2 mol C m-2 yr-1 in the sWEC and IS, respectively. Air-sea CO2 fluxes showed important inter-annual variability resulting in significant differences in the intensity and/or direction of annual fluxes. We scaled the mean annual fluxes over these provinces for the last decade and obtained the first annual average uptake of -1.11 ± 0.32 Tg C yr-1 for this part of the northwestern European continental shelf. Our study showed that combining VOS data with satellite observations can be a powerful tool to

  10. Accounting for observational uncertainties in the evaluation of low latitude turbulent air-sea fluxes simulated in a suite of IPSL model versions

    NASA Astrophysics Data System (ADS)

    Servonnat, Jerome; Braconnot, Pascale; Gainusa-Bogdan, Alina

    2015-04-01

    Turbulent momentum and heat (sensible and latent) fluxes at the air-sea interface are key components of the whole energetic of the Earth's climate and their good representation in climate models is of prime importance. In this work, we use the methodology developed by Braconnot & Frankignoul (1993) to perform a Hotelling T2 test on spatio-temporal fields (annual cycles). This statistic provides a quantitative measure accounting for an estimate of the observational uncertainty for the evaluation of low-latitude turbulent air-sea fluxes in a suite of IPSL model versions. The spread within the observational ensemble of turbulent flux data products assembled by Gainusa-Bogdan et al (submitted) is used as an estimate of the observational uncertainty for the different turbulent fluxes. The methodology holds on a selection of a small number of dominating variability patterns (EOFs) that are common to both the model and the observations for the comparison. Consequently it focuses on the large-scale variability patterns and avoids the possibly noisy smaller scales. The results show that different versions of the IPSL couple model share common large scale model biases, but also that there the skill on sea surface temperature is not necessarily directly related to the skill in the representation of the different turbulent fluxes. Despite the large error bars on the observations the test clearly distinguish the different merits of the different model version. The analyses of the common EOF patterns and related time series provide guidance on the major differences with the observations. This work is a first attempt to use such statistic on the evaluation of the spatio-temporal variability of the turbulent fluxes, accounting for an observational uncertainty, and represents an efficient tool for systematic evaluation of simulated air-seafluxes, considering both the fluxes and the related atmospheric variables. References Braconnot, P., and C. Frankignoul (1993), Testing Model

  11. Dynamics of air-sea CO2 fluxes in the North-West European Shelf based on Voluntary Observing Ship (VOS) and satellite observations

    NASA Astrophysics Data System (ADS)

    Marrec, P.; Cariou, T.; Macé, E.; Morin, P.; Salt, L. A.; Vernet, M.; Taylor, B.; Paxman, K.; Bozec, Y.

    2015-04-01

    From January 2011 to December 2013, we constructed a comprehensive pCO2 dataset based on voluntary observing ship (VOS) measurements in the Western English Channel (WEC). We subsequently estimated surface pCO2 and air-sea CO2 fluxes in north-west European continental shelf waters using multiple linear regressions (MLRs) from remotely sensed sea surface temperature (SST), chlorophyll a concentration (Chl a), the gas transfer velocity coefficient (K), photosynthetically active radiation (PAR) and modeled mixed layer depth (MLD). We developed specific MLRs for the seasonally stratified northern WEC (nWEC) and the permanently well-mixed southern WEC (sWEC) and calculated surface pCO2 with relative uncertainties of 17 and 16 μatm, respectively. We extrapolated the relationships obtained for the WEC based on the 2011-2013 dataset (1) temporally over a decade and (2) spatially in the adjacent Celtic and Irish Seas (CS and IS), two regions which exhibit hydrographical and biogeochemical characteristics similar to those of WEC waters. We validated these extrapolations with pCO2 data from the SOCAT database and obtained relatively robust results with an average precision of 4 ± 22 μatm in the seasonally stratified nWEC and the southern and northern CS (sCS and nCS), but less promising results in the permanently well-mixed sWEC, IS and Cap Lizard (CL) waters. On an annual scale, seasonally stratified systems acted as a sink of CO2 from the atmosphere of -0.4, -0.9 and -0.4 mol C m-2 year-1 in the nCS, sCS and nWEC, respectively, whereas, permanently well-mixed systems acted as source of CO2 to the atmosphere of 0.2, 0.4 and 0.4 mol C m-2 year-1 in the sWEC, CL and IS, respectively. Air-sea CO2 fluxes showed important inter-annual variability resulting in significant differences in the intensity and/or direction of annual fluxes. We scaled the mean annual fluxes over six provinces for the last decade and obtained the first annual average uptake of -0.95 Tg C year-1 for this

  12. Spatiotemporal variability and drivers of pCO2 and air-sea CO2 fluxes in the California Current System: an eddy-resolving modeling study

    NASA Astrophysics Data System (ADS)

    Turi, G.; Lachkar, Z.; Gruber, N.

    2014-02-01

    We quantify the CO2 source/sink nature of the California Current System (CalCS) and determine the drivers and processes behind the mean and spatiotemporal variability of the partial pressure of CO2 (pCO2) in the surface ocean. To this end, we analyze eddy-resolving, climatological simulations of a coupled physical-biogeochemical oceanic model on the basis of the Regional Oceanic Modeling System (ROMS). In the annual mean, the entire CalCS within 800 km of the coast and from ∼33° N to 46° N is essentially neutral with regard to atmospheric CO2: the model simulates an integrated uptake flux of -0.9 ± 3.6 Tg C yr-1, corresponding to an average flux density of -0.05 ± 0.20 mol C m-2 yr-1. This near zero flux is a consequence of an almost complete regional compensation between (i) strong outgassing in the nearshore region (first 100 km) that brings waters with high concentrations of dissolved inorganic carbon (DIC) to the surface and (ii) and a weaker, but more widespread uptake flux in the offshore region due to an intense biological reduction of this DIC, driven by the nutrients that are upwelled together with the DIC. The air-sea CO2 fluxes vary substantially in time, both on seasonal and sub-seasonal timescales, largely driven by variations in surface ocean pCO2. Most of the variability in pCO2 is associated with the seasonal cycle, with the exception of the nearshore region, where sub-seasonal variations driven by mesoscale processes dominate. In the regions offshore of 100 km, changes in surface temperature are the main driver, while in the nearshore region, changes in surface temperature, as well as anomalies in DIC and alkalinity (Alk) owing to changes in circulation, biological productivity and air-sea CO2 fluxes dominate. The prevalence of eddy-driven variability in the nearshore 100 km leads to a complex spatiotemporal mosaic of surface ocean pCO2 and air-sea CO2 fluxes that require a substantial observational effort to determine the source

  13. Air-sea exchange of gaseous mercury in the tropical coast (Luhuitou fringing reef) of the South China Sea, the Hainan Island, China.

    PubMed

    Ci, Zhijia; Zhang, Xiaoshan; Wang, Zhangwei

    2016-06-01

    The air-sea exchange of gaseous mercury (mainly Hg(0)) in the tropical ocean is an important part of the global Hg biogeochemical cycle, but the related investigations are limited. In this study, we simultaneously measured Hg(0) concentrations in surface waters and overlaying air in the tropical coast (Luhuitou fringing reef) of the South China Sea (SCS), Hainan Island, China, for 13 days on January-February 2015. The purpose of this study was to explore the temporal variation of Hg(0) concentrations in air and surface waters, estimate the air-sea Hg(0) flux, and reveal their influencing factors in the tropical coastal environment. The mean concentrations (±SD) of Hg(0) in air and total Hg (THg) in waters were 2.34 ± 0.26 ng m(-3) and 1.40 ± 0.48 ng L(-1), respectively. Both Hg(0) concentrations in waters (53.7 ± 18.8 pg L(-1)) and Hg(0)/THg ratios (3.8 %) in this study were significantly higher than those of the open water of the SCS in winter. Hg(0) in waters usually exhibited a clear diurnal variation with increased concentrations in daytime and decreased concentrations in nighttime, especially in cloudless days with low wind speed. Linear regression analysis suggested that Hg(0) concentrations in waters were positively and significantly correlated to the photosynthetically active radiation (PAR) (R (2) = 0.42, p < 0.001). Surface waters were always supersaturated with Hg(0) compared to air (the degree of saturation, 2.46 to 13.87), indicating that the surface water was one of the atmospheric Hg(0) sources. The air-sea Hg(0) fluxes were estimated to be 1.73 ± 1.25 ng m(-2) h(-1) with a large range between 0.01 and 6.06 ng m(-2) h(-1). The high variation of Hg(0) fluxes was mainly attributed to the greatly temporal variation of wind speed. PMID:26931659

  14. Does age matter in song bird vocal interactions? Results from interactive playback experiments

    PubMed Central

    2011-01-01

    The song of oscines provides an extensively studied model of age-dependent behaviour changes. Male and female receivers might use song characteristics to obtain information about the age of a signaller, which is often related to its quality. Whereas most of the age-dependent song changes have been studied in solo singing, the role of age in vocal interactions is less well understood. We addressed this issue in a playback study with common nightingales (Luscinia megarhynchos). Previous studies showed that male nightingales had smaller repertoires in their first year than older males and males adjusted their repertoire towards the most common songs in the breeding population. We now compared vocal interaction patterns in a playback study in 12 one year old and 12 older nightingales (cross-sectional approach). Five of these males were tested both in their first and second breeding season (longitudinal approach). Song duration and latency to respond did not differ between males of different ages in either approach. In the cross-sectional approach, one year old nightingales matched song types twice as often as did older birds. Similarly, in the longitudinal approach all except one bird reduced the number of song type matches in their second season. Individuals tended to overlap songs at higher rates in their second breeding season than in their first. The higher levels of song type matches in the first year and song overlapping by birds in their second year suggest that these are communicative strategies to establish relationships with competing males and/or choosy females. PMID:22071317

  15. Blast94: Bromine latitudinal air/sea transect 1994. Report on oceanic measurements of methyl bromide and other compounds. Technical memo

    SciTech Connect

    Lobert, J.M.; Butler, J.H.; Geller, L.S.; Yvon, S.A.; Montzka, S.A.

    1996-02-01

    Methyl bromide (CH3Br) is of particular interest because it is both produced and consumed in the ocean, thus allowing the ocean to act as a buffer for CH3Br in the atmosphere. The main objective of the two NOAA/CMDL Bromine Latitudinal Air/Sea Transect Expeditions has been to resolve the discrepancy in previously reported data for oceanic CH3Br, and to extend the understanding of the distribution and cycling of CH3Br between the atmosphere and ocean. This was pursued by making frequent, shipboard measurements of CH3Br in the surface water and the marine atmosphere along the cruise tracks and by obtaining depth profiles of CH3Br at selected stations. Secondary objectives included obtaining atmospheric and surface water data for other methyl halides, most notably CH3Cl, CH3I, CH2Br2, and CHBr3.

  16. Modeling the impact of air, sea, and land travel restrictions supplemented by other interventions on the emergence of a new influenza pandemic virus

    PubMed Central

    2012-01-01

    Background During the early stages of a new influenza pandemic, travel restriction is an immediate and non-pharmaceutical means of retarding incidence growth. It extends the time frame of effective mitigation, especially when the characteristics of the emerging virus are unknown. In the present study, we used the 2009 influenza A pandemic as a case study to evaluate the impact of regulating air, sea, and land transport. Other government strategies, namely, antivirals and hospitalizations, were also evaluated. Methods Hong Kong arrivals from 44 countries via air, sea, and land transports were imported into a discrete stochastic Susceptible, Exposed, Infectious and Recovered (SEIR) host-flow model. The model allowed a number of latent and infectious cases to pass the border, which constitutes a source of local disease transmission. We also modeled antiviral and hospitalization prevention strategies to compare the effectiveness of these control measures. Baseline reproduction rate was estimated from routine surveillance data. Results Regarding air travel, the main route connected to the influenza source area should be targeted for travel restrictions; imposing a 99% air travel restriction delayed the epidemic peak by up to two weeks. Once the pandemic was established in China, the strong land connection between Hong Kong and China rendered Hong Kong vulnerable. Antivirals and hospitalization were found to be more effective on attack rate reductions than travel restrictions. Combined strategies (with 99% restriction on all transport modes) deferred the peak for long enough to establish a vaccination program. Conclusion The findings will assist policy-makers with decisions on handling similar future pandemics. We also suggest regulating the extent of restriction and the transport mode, once restriction has been deemed necessary for pandemic control. Although travel restrictions have yet to gain social acceptance, they allow time for mitigation response when a new and

  17. An Approach to Minimizing Artifacts Caused by Cross-Sensitivity in the Determination of Air-Sea CO2 Flux Using the Eddy-Covariance Technique

    NASA Astrophysics Data System (ADS)

    Duan, Ziqiang; Gao, Huiwang; Gao, Zengxiang; Wang, Renlei; Xue, Yuhuan; Yao, Xiaohong

    2013-07-01

    The air-sea CO2 flux was measured from a research vessel in the North Yellow Sea in October 2007 using an open-path eddy-covariance technique. In 11 out of 64 samples, the normalized spectra of scalars (C}2, water vapour, and temperature) showed similarities. However, in the remaining samples, the normalized CO2 spectra were observed to be greater than those of water vapour and temperature at low frequencies. In this paper, the noise due to cross-sensitivity was identified through a combination of intercomparisons among the normalized spectra of three scalars and additional analyses. Upon examination, the cross-sensitivity noise appeared to be mainly present at frequencies {<}0.8 Hz. Our analysis also suggested that the high-frequency fluctuations of CO2 concentration (frequency {>}0.8 Hz) was probably less affected by the cross-sensitivity. To circumvent the cross-sensitivity issue, the cospectrum in the high-frequency range 0.8-1.5 Hz, instead of the whole range, was used to estimate the CO2 flux by taking the contribution of the high frequency to the CO2 flux to be the same as the contribution to the water vapour flux. The estimated air-sea CO2 flux in the North Yellow Sea was -0.039 ± 0.048 mg m^{-2} s^{-1}, a value comparable to the estimates using the inertial dissipation method and Edson's method (Edson et al., J Geophys Res 116:C00F10, 2011).

  18. The organic sea-surface microlayer in the upwelling region off the coast of Peru and potential implications for air-sea exchange processes

    NASA Astrophysics Data System (ADS)

    Engel, Anja; Galgani, Luisa

    2016-02-01

    The sea-surface microlayer (SML) is at the uppermost surface of the ocean, linking the hydrosphere with the atmosphere. The presence and enrichment of organic compounds in the SML have been suggested to influence air-sea gas exchange processes as well as the emission of primary organic aerosols. Here, we report on organic matter components collected from an approximately 50 µm thick SML and from the underlying water (ULW), ˜ 20 cm below the SML, in December 2012 during the SOPRAN METEOR 91 cruise to the highly productive, coastal upwelling regime off the coast of Peru. Samples were collected at 37 stations including coastal upwelling sites and off-shore stations with less organic matter and were analyzed for total and dissolved high molecular weight (> 1 kDa) combined carbohydrates (TCCHO, DCCHO), free amino acids (FAA), total and dissolved hydrolyzable amino acids (THAA, DHAA), transparent exopolymer particles (TEP), Coomassie stainable particles (CSPs), total and dissolved organic carbon (TOC, DOC), total and dissolved nitrogen (TN, TDN), as well as bacterial and phytoplankton abundance. Our results showed a close coupling between organic matter concentrations in the water column and in the SML for almost all components except for FAA and DHAA that showed highest enrichment in the SML on average. Accumulation of gel particles (i.e., TEP and CSP) in the SML differed spatially. While CSP abundance in the SML was not related to wind speed, TEP abundance decreased with wind speed, leading to a depletion of TEP in the SML at about 5 m s-1. Our study provides insight to the physical and biological control of organic matter enrichment in the SML, and discusses the potential role of organic matter in the SML for air-sea exchange processes.

  19. The Plasma Interaction Experiment /PIX/ - Description and flight qualification test program

    NASA Technical Reports Server (NTRS)

    Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

    1978-01-01

    The Plasma Interaction Experiment (PIX) is a battery powered preprogrammed auxiliary payload on the Landsat-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus 1 kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage-biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

  20. Laboratory plasma interactions experiments: Results and implications to future space systems

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1986-01-01

    The experimental results discussed show the significance of the effects caused by spacecraft plasma interactions, in particular the generation of Electromagnetic Interference. As the experimental results show, the magnitude of the adverse effects induced by Plasma Interactions (PI) will be more significant for spacecraft of the next century. Therefore, research is needed to control possible adverse effects. Several techniques to control the selected PI effects are discussed. Tests, in the form of flight experiments, are needed to validate these proposed ideas.

  1. Integrating theory into disturbance interaction experiments to better inform ecosystem management.

    PubMed

    Foster, Claire N; Sato, Chloe F; Lindenmayer, David B; Barton, Philip S

    2016-04-01

    Managing multiple, interacting disturbances is a key challenge to biodiversity conservation, and one that will only increase as global change drivers continue to alter disturbance regimes. Theoretical studies have highlighted the importance of a mechanistic understanding of stressor interactions for improving the prediction and management of interactive effects. However, many conservation studies are not designed or interpreted in the context of theory and instead focus on case-specific management questions. This is a problem as it means that few studies test the relationships highlighted in theoretical models as being important for ecological management. We explore the extent of this problem among studies of interacting disturbances by reviewing recent experimental studies of the interaction between fire and grazing in terrestrial ecosystems. Interactions between fire and grazing can occur via a number of pathways; one disturbance can modify the other's likelihood, intensity or spatial distribution, or one disturbance can alter the other's impacts on individual organisms. The strength of such interactions will vary depending on disturbance attributes (e.g. size or intensity), and this variation is likely to be nonlinear. We show that few experiments testing fire-grazing interactions are able to identify the mechanistic pathway driving an observed interaction, and most are unable to detect nonlinear effects. We demonstrate how these limitations compromise the ability of experimental studies to effectively inform ecological management. We propose a series of adjustments to the design of disturbance interaction experiments that would enable tests of key theoretical pathways and provide the deeper ecological understanding necessary for effective management. Such considerations are relevant to studies of a broad range of ecological interactions and are critical to informing the management of disturbance regimes in the context of accelerating global change. PMID

  2. Implementing Interactive Lecture Experiments in Large Introductory Physics Courses (Part I)

    NASA Astrophysics Data System (ADS)

    Moll, Rachel; Milner-Bolotin, M. M.; McPhee, K.; Zhdanovich, S.; Kotlicki, A.; Rieger, G.; Bates, F.

    2006-12-01

    This presentation describes a pedagogical approach, Interactive Lecture Experiments (ILE), which builds on Interactive Lecture Demonstrations proposed by Sokoloff and Thornton (2004) and extends it by providing students with the opportunity to analyze experiments demonstrated in the lecture outside of the classroom and report the result of their analysis suing Peer Response System during the following lecture. Real time experimental data is collected, using Logger Pro technology combined with digital video recording. Then the data is uploaded to the Internet and made available to the students for further analysis. Student understanding of the experiment is assessed in the following lecture using clickers and conceptual questions. The goal of this project is to use ILE activities to make large lectures more interactive and to promote student interest in science, critical thinking and data analysis skills. Sokoloff, D.R. and R.K. Thornton (2004). Interactive Lecture Demonstrations: Active Learning in Introductory Physics, John Wiley and Sons, INC. Interactive Lecture Experiments at the University of British Columbia: http://www.physics.ubc.ca/ year1lab/p100/LectureLabs/lectureLabs.html

  3. Perceptions and experiences of people with mental illness regarding their interactions with police.

    PubMed

    Livingston, James D; Desmarais, Sarah L; Verdun-Jones, Simon; Parent, Richard; Michalak, Erin; Brink, Johann

    2014-01-01

    This study examined the perceptions and lived experiences of people with mental illness in relation to their interactions with the police. A community-based participatory research approach was used and a procedural justice theoretical perspective guided the study. In-depth, semi-structured interviews were conducted by peer researchers with 60 people with mental illness who had interacted with the police and were living in Metro Vancouver, Canada. Among the study participants, contact with the police was frequent and occurred under a diverse range of circumstances. The majority of participants perceived being treated in a procedurally just manner by the police officer(s) who were involved in their most recent interaction. Almost three-quarters (n=43, 72%) of participants were generally satisfied with how the police officer(s) had handled their most recent interaction. The slight majority of participants (n=30, 51%) rated their previous contacts with the police as a positive experience overall, with 32% (n=19) indicating that their previous interactions with the police were negative life experiences. The findings paint a more balanced picture than that which is often portrayed by the media. Emphasizing a procedural justice framework for police handling of situations involving people with mental illness is a vital step toward improving how these interactions are experienced and perceived. PMID:24684784

  4. Colloidal Disorder-Order Transition Experiment Probes Particle Interactions in Microgravity

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Everything in the universe is made up of the same basic building blocks - atoms. All physical properties of matter such as weight, hardness, and color are determined by the kind of atoms present and the way they interact with each other. The Colloidal Disorder-Order Transition (CDOT) shuttle flight experiment tested fundamental theories that model atomic interactions. The experiment was part of the Second United States Microgravity Laboratory (USML-2) aboard the Space Shuttle Columbia, which flew from October 20 to November 5, 1995.

  5. The FrPNC Experiment, weak interaction studies in Francium at TRIUMF

    NASA Astrophysics Data System (ADS)

    Gomez, E.; Aubin, S.; Collister, R.; Behr, J. A.; Gwinner, G.; Orozco, L. A.; Pearson, M. R.; Tandecki, M.; Sheng, D.; Zhang, J.

    2012-09-01

    Francium is an excellent system to study the nuclear weak force due to its large nucleus and relatively simple atomic structure. The FrPNC experiment has a facility to produce cold trapped atomic francium samples for parity non-conservation studies. We are preparing to measure both the nuclear spin independent and dependent parts of the weak interaction in francium. The first one gives information about weak neutral currents at low energies, while the second one is sensitive to weak interactions between nucleons. We present the current status of the experiment.

  6. Nonstandard interactions spoiling the C P violation sensitivity at DUNE and other long baseline experiments

    NASA Astrophysics Data System (ADS)

    Masud, Mehedi; Mehta, Poonam

    2016-07-01

    It is by now established that neutrino oscillations occur due to nonzero masses and parameters in the leptonic mixing matrix. The extraction of oscillation parameters may be complicated due to subleading effects such as nonstandard neutrino interactions and one needs to have a fresh look how a particular parameter value is inferred from experimental data. In the present work, we focus on an important parameter entering the oscillation framework-the leptonic C P -violating phase δ , about which we know very little. We demonstrate that the sensitivity to C P violation gets significantly impacted due to nonstandard neutrino interaction effects for the upcoming long baseline experiment, Deep Underground Neutrino Experiment. We also draw a comparison with the sensitivities of other ongoing neutrino beam experiments such as NO ν A and T2K as well as a future generation experiment, T2HK.

  7. Embodied social interaction constitutes social cognition in pairs of humans: A minimalist virtual reality experiment

    PubMed Central

    Froese, Tom; Iizuka, Hiroyuki; Ikegami, Takashi

    2014-01-01

    Scientists have traditionally limited the mechanisms of social cognition to one brain, but recent approaches claim that interaction also realizes cognitive work. Experiments under constrained virtual settings revealed that interaction dynamics implicitly guide social cognition. Here we show that embodied social interaction can be constitutive of agency detection and of experiencing another's presence. Pairs of participants moved their “avatars” along an invisible virtual line and could make haptic contact with three identical objects, two of which embodied the other's motions, but only one, the other's avatar, also embodied the other's contact sensor and thereby enabled responsive interaction. Co-regulated interactions were significantly correlated with identifications of the other's avatar and reports of the clearest awareness of the other's presence. These results challenge folk psychological notions about the boundaries of mind, but make sense from evolutionary and developmental perspectives: an extendible mind can offload cognitive work into its environment. PMID:24419102

  8. Police officers’ experiences of supportive and unsupportive social interactions following traumatic incidents

    PubMed Central

    Evans, Rachel; Pistrang, Nancy; Billings, Jo

    2013-01-01

    Background Police officers are routinely exposed to potentially traumatic incidents yet the majority do not develop post-traumatic stress disorder (PTSD). Social support has been identified as one factor that may maintain wellbeing in this population, although what constitutes supportive or unsupportive interactions is unclear. Objective To explore police officers’ experiences of supportive and unsupportive interactions following distressing incidents. Method Semi-structured interviews were conducted with 19 police officers. Transcripts were analysed using Braun and Clarke's (2006) thematic analysis approach. Results Participants described a range of supportive interactions with colleagues, friends, and family, as well as social constraints that hindered interactions. Ambivalence about talking about the impact of distressing events was striking throughout the accounts. The context and source of available support, as well as beliefs about talking, influenced their interactions. Humour was a central feature of interactions with colleagues; more emotional talk occurred with partners and close family, albeit with officers limiting details in order to protect others. Conclusions The findings provide tentative insights into the processes of social support that may contribute to the resilience of police officers following traumatic incidents. Further research is needed to examine whether the experiences of supportive and unsupportive interactions differ for those with and without PTSD. PMID:23516046

  9. Quantifying long-range correlations and 1/f patterns in a minimal experiment of social interaction

    PubMed Central

    Bedia, Manuel G.; Aguilera, Miguel; Gómez, Tomás; Larrode, David G.; Seron, Francisco

    2014-01-01

    In recent years, researchers in social cognition have found the “perceptual crossing paradigm” to be both a theoretical and practical advance toward meeting particular challenges. This paradigm has been used to analyze the type of interactive processes that emerge in minimal interactions and it has allowed progress toward understanding of the principles of social cognition processes. In this paper, we analyze whether some critical aspects of these interactions could not have been observed by previous studies. We consider alternative indicators that could complete, or even lead us to rethink, the current interpretation of the results obtained from both experimental and simulated modeling in the fields of social interactions and minimal perceptual crossing. In particular, we discuss the possibility that previous experiments have been analytically constrained to a short-term dynamic type of player response. Additionally, we propose the possibility of considering these experiments from a more suitable framework based on the use and analysis of long-range correlations and fractal dynamics. We will also reveal evidence supporting the idea that social interactions are deployed along many scales of activity. Specifically, we propose that the fractal structure of the interactions could be a more adequate framework to understand the type of social interaction patterns generated in a social engagement. PMID:25429277

  10. Students' experiences with interactivity and learning in a high school physics multimedia distance learning course

    NASA Astrophysics Data System (ADS)

    Villarreal-Stewart, Irene

    The purpose guiding this research has been to learn about and describe the phenomena of interactivity from the learners' perspectives and to learn which of the interactivity affordances and practices were actually used by students and why in the process of learning physics using an interactive multimedia distance learning course system. The bigger purpose behind learning about and describing interactivity has been to gain knowledge and perspective for its instructional design to benefit the learner, the school as curriculum implementer, and instructional media designers to create better products. Qualitative methodology in the interpretivist tradition was used, that is, in-depth interviews and on-site observations, to gain understanding of interactivity from the learners' perspective and to gain understanding of the student learning context impacting and shaping the students' interactivity experiences. NVivo was used to sort, organize and index data. All data were read on three levels: literally, interpretively, and reflexively; and were read comparatively to other perspectives to get descriptions and interpretations that were holistic to the implementation and had potential insight to improve practice for instructional designers, teachers, administrators, specifically to improve the learning experience for students. Site-Specific Findings: Students watched videos, resisted using phone and e-mail, and worked math problems to demonstrate learning, which resulted in very little interactivity, virtually no dialogue about physics, no physical activity, one-way communication, multifaceted dissatisfaction, student need for teacher involvement in the learning enterprise, student appreciation for interactivity, and expressed desire for a real, live teacher. I also found that some students did experience the system as interactive, did experience learner control and self-directed learning, and despite dissatisfaction, liked and appreciated the course. Wider Applications

  11. Resident physician interactions with surrogate decision-makers: the resident experience.

    PubMed

    Reckrey, Jennifer M; McKee, M Diane; Sanders, Justin J; Lipman, Hannah I

    2011-12-01

    This study explored interactions between medical residents and patient surrogates in order to clarify resident understanding of roles and relationships, resident emotional experience, and resident learning processes. Qualitative analysis of in-depth interviews were used involving three family medicine residency programs serving culturally diverse, urban, underserved patient populations. Eighteen second- and third-year trainees described a memorable interaction with a surrogate and then were prompted to discuss their learning experience and their role in the interaction. Interviews were transcribed verbatim and analyzed through an iterative process. Residents experienced significant emotional burden during interactions yet continued to value their relationships with surrogates. Despite their reservations about giving recommendations, residents adopted a variety of roles with surrogates as they gave support, information, and advice. Although residents reported little formal education about surrogate decision-making, they relied on passive role modeling and their own previous experiences to help surrogates make decisions. Residents have complex and emotionally significant interactions with surrogates despite minimal formal education about surrogate decision-making. Educational efforts should seek to help residents understand their own emotions and the ethical beliefs that underlie the roles they adopt with surrogates. This will help residents to facilitate value-based conversations with surrogates and better support surrogates in the decision-making process. PMID:22092192

  12. User Experience of Mobile Interactivity: How Do Mobile Websites Affect Attitudes and Relational Outcomes?

    ERIC Educational Resources Information Center

    Dou, Xue

    2013-01-01

    Mobile media offer new opportunities for fostering communications between individuals and companies. Corporate websites are being increasingly accessed via smart phones and companies are scrambling to offer a mobile-friendly user experience on their sites. However, very little is known about how interactivity in the mobile context affects user…

  13. Enhancing Children's Language Learning and Cognition Experience through Interactive Kinetic Typography

    ERIC Educational Resources Information Center

    Lau, Newman M. L.; Chu, Veni H. T.

    2015-01-01

    This research aimed at investigating the method of using kinetic typography and interactive approach to conduct a design experiment for children to learn vocabularies. Typography is the unique art and technique of arranging type in order to make language visible. By adding animated movement to characters, kinetic typography expresses language…

  14. Early steps towards quarks and their interactions using neutrino beams in CERN bubble chamber experiments

    NASA Astrophysics Data System (ADS)

    Perkins, Don H.

    2016-06-01

    Results from neutrino experiments at CERN in the1970's, using bubble chamber detectors filled with heavy liquids, gave early evidence for the existence of quarks and gluons as real dynamical objects. In detail, the measured moments of the non-singlet structure functions provided crucial support for the validity of the present theory of the strong inter-quark interactions, quantum chromodynamics.

  15. On the Use of Interactive Texts in Undergraduate Chemical Reaction Engineering Courses: A Pedagogical Experience

    ERIC Educational Resources Information Center

    Asensio, Daniela A.; Barassi, Francisca J.; Zambon, Mariana T.; Mazza, Germán D.

    2010-01-01

    This paper describes the results of a pedagogical experience carried out at the University of Comahue, Argentina, with an interactive text (IT) concerning Homogeneous Chemical Reactors Analysis. The IT was built on the frame of the "Mathematica" software with the aim of providing students with a robust computational tool. Students'…

  16. Effects of Professional Experience and Group Interaction on Information Requested in Analyzing IT Cases

    ERIC Educational Resources Information Center

    Lehmann, Constance M.; Heagy, Cynthia D.

    2008-01-01

    The authors investigated the effects of professional experience and group interaction on the information that information technology professionals and graduate accounting information system (AIS) students request when analyzing business cases related to information systems design and implementation. Understanding these effects can contribute to…

  17. How Do Interaction Experiences Influence Doctoral Students' Academic Pursuits in Biomedical Research?

    ERIC Educational Resources Information Center

    Kong, Xiaoqing; Chakraverty, Devasmita; Jeffe, Donna B.; Andriole, Dorothy A.; Wathington, Heather D.; Tai, Robert H.

    2013-01-01

    This exploratory qualitative study investigated how doctoral students reported their personal and professional interaction experiences that they believed might facilitate or impede their academic pursuits in biomedical research. We collected 19 in-depth interviews with doctoral students in biomedical research from eight universities, and we based…

  18. Men's and Women's Satisfying and Frustrating Experiences in Close Relationship Interactions.

    ERIC Educational Resources Information Center

    Friedland, Randi

    Clinicians and family theorists have speculated that men and women differ in their orientations to close relationships, although these stereotypic patterns have not been investigated empirically. To determine whether people's interactional experiences are characterized by distinctive, sex-linked orientations to expressiveness and caring, 252 men…

  19. Early steps towards quarks and their interactions using neutrino beams in CERN bubble chamber experiments

    NASA Astrophysics Data System (ADS)

    Perkins, Don H.

    2016-05-01

    Results from neutrino experiments at CERN in the1970's, using bubble chamber detectors filled with heavy liquids, gave early evidence for the existence of quarks and gluons as real dynamical objects. In detail, the measured moments of the non-singlet structure functions provided crucial support for the validity of the present theory of the strong inter-quark interactions, quantum chromodynamics.

  20. Professional Interaction, Relevant Practical Experience, and Intellectual Contributions at Nondoctoral AACSB-Accredited Accounting Programs

    ERIC Educational Resources Information Center

    Arlinghaus, Barry P.

    2008-01-01

    In this article, the author discusses a survey of faculty members at nondoctoral AACSB-accredited accounting programs in the United States. The purpose of the survey was to determine the environment for professional interaction and relevant experience in light of institutional demands for intellectual contributions. The findings show that the…

  1. Plasma-wall interaction data needs critical to a Burning Core Experiment (BCX)

    SciTech Connect

    Not Available

    1985-11-01

    The Division of Development and Technology has sponsored a four day US-Japan workshop ''Plasma-Wall Interaction Data Needs Critical to a Burning Core Experiment (BCX)'', held at Sandia National Laboratories, Livermore, California on June 24 to 27, 1985. The workshop, which brought together fifty scientists and engineers from the United States, Japan, Germany, and Canada, considered the plasma-material interaction and high heat flux (PMI/HHF) issues for the next generation of magnetic fusion energy devices, the Burning Core Experiment (BCX). Materials options were ranked, and a strategy for future PMI/HHF research was formulated. The foundation for international collaboration and coordination of this research was also established. This volume contains the last three of the five technical sessions. The first of the three is on plasma materials interaction issues, the second is on research facilities and the third is from smaller working group meetings on graphite, beryllium, advanced materials and future collaborations.

  2. Development of AN Interactive MR Fluid Experiment for Smart Materials Curricula

    NASA Astrophysics Data System (ADS)

    Bannerot, R.; Song, G.

    This paper presents the development of an interactive MR (Magneto-Rheological) fluid experiment. The hands-on experiment is developed to introduce MR fluids to students who are interested in this smart fluid. This apparatus is also used as a teaching tool for courses in smart materials. The experiment is designed to show students the basic operations of MR fluids and some common applications. This interactive experiment includes three devices with associated control buttons and all the devices are housed in a clear display case for easy visualization. 1) MR fluid morphing device, which clearly shows the morphing of MR material between fluid and semi-solid with the control of the electromagnet. 2) MR brake, which allow a user clearly feel the change of resistance level of the crank shaft with increasing of current to the electromagnets. 3) Vibration damping using MR fluid damper, which shows that the vibration of a platform induced by a rotating motor with an imbalanced mass can be suppressed by a simple MR fluid damper. This interactive experiment is fully autonomous and has been used in University of Houston. It has been demonstrated that it is an effective tool to assist student to learn MR fluids.

  3. Laser-plasma interaction in the context of inertial fusion: experiments and modeling

    NASA Astrophysics Data System (ADS)

    Labaune, C.; Lewis, K.; Bandulet, H.; Depierreux, S.; Hüller, S.; Masson-Laborde, P. E.; Pesme, D.; Loiseau, P.

    2007-08-01

    Many nonlinear processes may affect the laser beam propagation and the laser energy deposition in the underdense plasma surrounding the pellet. These processes, associated with anomalous and nonlinear absorption mechanisms, are fundamental issues in the context of Inertial Confinement Fusion. The work presented in this article refers to laser-plasma interaction experiments which were conducted under well-controlled conditions, and to their theoretical and numerical modeling. Thanks to important diagnostics improvements, the plasma and laser parameters were sufficiently characterized in these experiments to make it possible to carry out numerical simulations modeling the laser plasma interaction in which the hydrodynamics conditions were very close to the experimental ones. Two sets of experiments were carried out with the LULI 2000 and the six beam LULI laser facilities. In the first series of experiments, the interaction between two single hot spots was studied as a function of their distance, intensity and light polarization. In the second series, the intensity distribution of stimulated Brillouin scattering (SBS) inside the plasma was studied by means of a new temporally resolved imaging system. Two-dimensional (2D) simulations were carried out with our code Harmony2D in order to model these experiments. For both series of experiments, the numerical results show a very good agreement with the experimental ones for what concerns the main SBS features, namely the spatial and temporal behavior of the SBS-driven acoustic waves, as well as the average SBS reflectivities. Thus, these well diagnosed experiments, carried out with well defined conditions, make it possible to benchmark our theoretical and numerical modelings and, hence, to improve our predictive capabilities for future experiments.

  4. Light sterile neutrinos, lepton number violating interactions and short baseline neutrino experiments

    NASA Astrophysics Data System (ADS)

    Babu, K. S.; McKay, D. W.; Mocioiu, Irina; Pakvasa, Sandip

    2016-06-01

    We develop the consequences of introducing a purely leptonic, non-standard interaction (NSI) ΔL = 2, four-fermion effective Lagrangian and standard model neutrino mixing with a fourth, sterile neutrino in the analysis of short-baseline, neutrino experiments. We focus on the muon decay at rest (DAR) results from the Liquid Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford medium Energy Neutrino Experiment (KARMEN), seeking a reconciliation between the two. Both v¯e appearance from v¯μ oscillation and v¯e survival after production from NSI decay of the µ+ contribute to the expected signal. This is a unique feature of our scheme. We comment on further implications of the lepton number violating interaction and sterile neutrino-standard neutrino mixing.

  5. Residents' perceptions and experiences of social interaction and participation in leisure activities in residential aged care.

    PubMed

    Thomas, Jessica E; O'Connell, Beverly; Gaskin, Cadeyrn J

    2013-10-01

    Social interaction and participation in leisure activities are positively related to the health and well-being of elderly people. The main focus of this exploratory study was to investigate elderly peoples' perceptions and experiences of social interaction and leisure activities living in a residential aged care (RAC) facility. Six residents were interviewed. Themes emerging from discussions about their social interactions included: importance of family, fostering friendships with fellow residents, placement at dining room tables, multiple communication methods, and minimal social isolation and boredom. Excursions away from the RAC facility were favourite activities. Participants commonly were involved in leisure activities to be socially connected. Poor health, family, the RAC facility, staffing, transportation, and geography influenced their social interaction and participation in leisure activities. The use of new technologies and creative problem solving with staff are ways in which residents could enhance their social lives and remain engaged in leisure activities. PMID:24299253

  6. Roles of biological and physical processes in driving seasonal air-sea CO2 flux in the Southern Ocean: New insights from CARIOCA pCO2

    NASA Astrophysics Data System (ADS)

    Merlivat, L.; Boutin, J.; Antoine, D.

    2015-07-01

    On a mean annual basis, the Southern Ocean is a sink for atmospheric CO2. However the seasonality of the air-sea CO2 flux in this region is poorly documented. We investigate processes regulating air-sea CO2 flux in a large area of the Southern Ocean (38°S-55°S, 60°W-60°E) that represents nearly one third of the subantarctic zone. A seasonal budget of CO2 partial pressure, pCO2 and of dissolved inorganic carbon, DIC in the mixed layer is assessed by quantifying the impacts of biology, physics and thermodynamical effect on seawater pCO2. A focus is made on the quantification at a monthly scale of the biological consumption as it is the dominant process removing carbon from surface waters. In situ biological carbon production rates are estimated from high frequency estimates of DIC along the trajectories of CARIOCA drifters in the Atlantic and Indian sector of the Southern Ocean during four spring-summer seasons over the 2006-2009 period. Net community production (NCP) integrated over the mixed layer is derived from the daily change of DIC, and mixed layer depth estimated from Argo profiles. Eleven values of NCP are estimated and range from 30 to 130 mmol C m- 2 d- 1. They are used as a constraint for validating satellite net primary production (NPP). A satellite data-based global model is used to compute depth integrated net primary production, NPP, for the same periods along the trajectories of the buoys. Realistic NCP/NPP ratios are obtained under the condition that the SeaWiFS chlorophyll are corrected by a factor of ≈ 2-3, which is an underestimation previously reported for the Southern Ocean. Monthly satellite based NPP are computed over the 38°S-55°S, 60°W-60°E area. pCO2 derived from these NPP combined with an export ratio, and taking into account the impact of physics and thermodynamics is in good agreement with the pCO2 seasonal climatology of Takahashi (2009). On an annual timescale, mean NCP values, 4.4 to 4.9 mol C m- 2 yr- 1 are ≈ 4-5 times

  7. Synoptic evaluation of carbon cycling in Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air-sea CO2 fluxes

    NASA Astrophysics Data System (ADS)

    Forest, A.; Coupel, P.; Else, B.; Nahavandian, S.; Lansard, B.; Raimbault, P.; Papakyriakou, T.; Gratton, Y.; Fortier, L.; Tremblay, J.-É.; Babin, M.

    2013-10-01

    The accelerated decline in Arctic sea ice combined with an ongoing trend toward a more dynamic atmosphere is modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration) responds to changes and modulates air-sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in southeastern Beaufort Sea (Arctic Ocean), we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air-sea CO2 exchange, with the aim of identifying indices of ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air-sea CO2 fluxes. The mean atmospheric forcing was a mild upwelling-favorable wind (~5 km h-1) blowing from the N-E and a decaying ice cover (<80% concentration) was observed beyond the shelf, the latter being fully exposed to the atmosphere. We detected some areas where the surface mixed layer was net autotrophic owing to high rates of primary production (PP), but the ecosystem was overall net heterotrophic. The region acted nonetheless as a sink for atmospheric CO2 with a mean uptake rate of -2.0 ± 3.3 mmol C m-2d-1. We attribute this discrepancy to: (1) elevated PP rates (>600 mg C m-2d-1) over the shelf prior to our survey, (2) freshwater dilution by river runoff and ice melt, and (3) the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (>10mmol C m-2d-1). Although generally <100 mg C m-2d-1, daily PP rates cumulated to a total PP of ~437.6 × 103 t C, which was roughly twice higher than the organic carbon delivery by river inputs (~241.2 × 103 t C). Subsurface PP represented 37.4% of total PP for the

  8. Air sea gas transfer velocity estimates from the Jason-1 and TOPEX altimeters: Prospects for a long-term global time series

    NASA Astrophysics Data System (ADS)

    Glover, David M.; Frew, Nelson M.; McCue, Scott J.

    2007-06-01

    Estimation of global and regional air-sea fluxes of climatically important gases is a key goal of current climate research programs. Gas transfer velocities needed to compute these fluxes can be estimated by combining altimeter-derived mean square slope with an empirical relation between transfer velocity and mean square slope derived from field measurements of gas fluxes and small-scale wave spectra [Frew, N.M., Bock, E.J., Schimpf, U., Hara, T., Hauβecker, H., Edson, J.B., McGillis, W.R., Nelson, R.K., McKenna, S.P., Uz, B.M., Jähne, B., 2004. Air-sea gas transfer: Its dependence on wind stress, small-scale roughness and surface films, J. Geophys. Res., 109, C08S17, doi: 10.1029/2003JC002131.]. We previously reported initial results from a dual-frequency (Ku- and C-band) altimeter algorithm [Glover, D.M., Frew, N.M., McCue, S.J., Bock, E.J., 2002. A Multi-year Time Series of Global Gas Transfer Velocity from the TOPEX Dual Frequency, Normalized Radar Backscatter Algorithm, In: Gas Transfer at Water Surfaces, editors: Donelan, M., Drennan, W., Saltzman, E., and Wanninkhof, R., Geophysical Monograph 127, American Geophysical Union, Washington, DC, 325-331.] for estimating the air-sea gas transfer velocity ( k) from the mean square slope of short wind waves (40-100 rad/m) and derived a 6-year time series of global transfer velocities based on TOPEX observations. Since the launch of the follow-on altimeter Jason-1 in December 2001 and commencement of the TOPEX/Jason-1 Tandem Mission, we have extended this time series to 12 years, with improvements to the model parameters used in our algorithm and using the latest corrected data releases. The prospect of deriving multi-year and interdecadal time series of gas transfer velocity from TOPEX, Jason-1 and follow-on altimeter missions depends on precise intercalibration of the normalized backscatter. During the Tandem Mission collinear phase, both satellites followed identical orbits with a mere 73-s time separation. The

  9. Trophic and Non-Trophic Interactions in a Biodiversity Experiment Assessed by Next-Generation Sequencing

    PubMed Central

    Tiede, Julia; Wemheuer, Bernd; Traugott, Michael; Daniel, Rolf; Tscharntke, Teja; Ebeling, Anne; Scherber, Christoph

    2016-01-01

    Plant diversity affects species richness and abundance of taxa at higher trophic levels. However, plant diversity effects on omnivores (feeding on multiple trophic levels) and their trophic and non-trophic interactions are not yet studied because appropriate methods were lacking. A promising approach is the DNA-based analysis of gut contents using next generation sequencing (NGS) technologies. Here, we integrate NGS-based analysis into the framework of a biodiversity experiment where plant taxonomic and functional diversity were manipulated to directly assess environmental interactions involving the omnivorous ground beetle Pterostichus melanarius. Beetle regurgitates were used for NGS-based analysis with universal 18S rDNA primers for eukaryotes. We detected a wide range of taxa with the NGS approach in regurgitates, including organisms representing trophic, phoretic, parasitic, and neutral interactions with P. melanarius. Our findings suggest that the frequency of (i) trophic interactions increased with plant diversity and vegetation cover; (ii) intraguild predation increased with vegetation cover, and (iii) neutral interactions with organisms such as fungi and protists increased with vegetation cover. Experimentally manipulated plant diversity likely affects multitrophic interactions involving omnivorous consumers. Our study therefore shows that trophic and non-trophic interactions can be assessed via NGS to address fundamental questions in biodiversity research. PMID:26859146

  10. Trophic and Non-Trophic Interactions in a Biodiversity Experiment Assessed by Next-Generation Sequencing.

    PubMed

    Tiede, Julia; Wemheuer, Bernd; Traugott, Michael; Daniel, Rolf; Tscharntke, Teja; Ebeling, Anne; Scherber, Christoph

    2016-01-01

    Plant diversity affects species richness and abundance of taxa at higher trophic levels. However, plant diversity effects on omnivores (feeding on multiple trophic levels) and their trophic and non-trophic interactions are not yet studied because appropriate methods were lacking. A promising approach is the DNA-based analysis of gut contents using next generation sequencing (NGS) technologies. Here, we integrate NGS-based analysis into the framework of a biodiversity experiment where plant taxonomic and functional diversity were manipulated to directly assess environmental interactions involving the omnivorous ground beetle Pterostichus melanarius. Beetle regurgitates were used for NGS-based analysis with universal 18S rDNA primers for eukaryotes. We detected a wide range of taxa with the NGS approach in regurgitates, including organisms representing trophic, phoretic, parasitic, and neutral interactions with P. melanarius. Our findings suggest that the frequency of (i) trophic interactions increased with plant diversity and vegetation cover; (ii) intraguild predation increased with vegetation cover, and (iii) neutral interactions with organisms such as fungi and protists increased with vegetation cover. Experimentally manipulated plant diversity likely affects multitrophic interactions involving omnivorous consumers. Our study therefore shows that trophic and non-trophic interactions can be assessed via NGS to address fundamental questions in biodiversity research. PMID:26859146

  11. A new multimodal interactive way of subjective scoring of 3D video quality of experience

    NASA Astrophysics Data System (ADS)

    Kim, Taewan; Lee, Kwanghyun; Lee, Sanghoon; Bovik, Alan C.

    2014-03-01

    People that watch today's 3D visual programs, such as 3D cinema, 3D TV and 3D games, experience wide and dynamically varying ranges of 3D visual immersion and 3D quality of experience (QoE). It is necessary to be able to deploy reliable methodologies that measure each viewers subjective experience. We propose a new methodology that we call Multimodal Interactive Continuous Scoring of Quality (MICSQ). MICSQ is composed of a device interaction process between the 3D display and a separate device (PC, tablet, etc.) used as an assessment tool, and a human interaction process between the subject(s) and the device. The scoring process is multimodal, using aural and tactile cues to help engage and focus the subject(s) on their tasks. Moreover, the wireless device interaction process makes it possible for multiple subjects to assess 3D QoE simultaneously in a large space such as a movie theater, and at di®erent visual angles and distances.

  12. PHENIX (Pioneering High Energy Nuclear Interaction eXperiment) Data Plots from the PHENIX Plot Database

    DOE Data Explorer

    The PHENIX Experiment is the largest of the four experiments currently taking data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons.The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma.[From http://www.phenix.bnl.gov/phenix/WWW/intro/] The PHENIX plot database allows searching by collision species, energies of the X and Y axis, and specific runs. Figures and data plots from published PHENIX papers are also available at http://www.phenix.bnl.gov//WWW/talk/pub_papers.php. (Specialized Interface)

  13. PHENIX (Pioneering High Energy Nuclear Interaction eXperiment): Data Tables and Figures from Published Papers

    DOE Data Explorer

    The PHENIX Experiment is the largest of the four experiments currently taking data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. More than 60 published papers and preprints are listed here with links to the full text and separate links to the supporting PHENIX data in plain text tables and to EPS and GIF figures from the papers.

  14. Interactive Web-based Learning Modules Prior to General Medicine Advanced Pharmacy Practice Experiences

    PubMed Central

    Walton, Alison M.; Nisly, Sarah A.

    2015-01-01

    Objective. To implement and evaluate interactive web-based learning modules prior to advanced pharmacy practice experiences (APPEs) on inpatient general medicine. Design. Three clinical web-based learning modules were developed for use prior to APPEs in 4 health care systems. The aim of the interactive modules was to strengthen baseline clinical knowledge before the APPE to enable the application of learned material through the delivery of patient care. Assessment. For the primary endpoint, postassessment scores increased overall and for each individual module compared to preassessment scores. Postassessment scores were similar among the health care systems. The survey demonstrated positive student perceptions of this learning experience. Conclusion. Prior to inpatient general medicine APPEs, web-based learning enabled the standardization and assessment of baseline student knowledge across 4 health care systems. PMID:25995515

  15. Effects of interaction experiences and undergraduate coursework on attitudes toward gay and lesbian issues.

    PubMed

    Sevecke, Jessica R; Rhymer, Katrina N; Almazan, Elbert P; Jacob, Susan

    2015-01-01

    College experiences can expand knowledge, decrease negative stereotypes, and increase acceptance toward diversity, especially regarding gay and lesbian issues. This study found that the more interaction undergraduate students have with gay and lesbian people on campus, the more accepting their attitudes are regarding (1) same-sex, consensual sex, (2) same-sex relations between adults is not unnatural, (3) vote for a gay presidential candidate, (4) friends with a feminine man, (5) friends with a masculine woman, (6) knowledge of GL issues important for future career, and (7) comfortable with GL roommate. Furthermore, the more undergraduate students are exposed to coursework addressing gay and lesbian issues, the more positive their attitudes are regarding the importance of knowledge of gay/lesbian issues for future career and comfort with a gay/lesbian roommate. Discussion explores possible long-term implications of systematic interaction experiences and coursework at all levels within the educational system to prevent negative attitude formation. PMID:25531799

  16. Velocity evolution of electro-magnetically driven shock wave for beam-dissociated hydrogen interaction experiment

    NASA Astrophysics Data System (ADS)

    Kondo, Kotaro; Oguri, Yoshiyuki

    2016-03-01

    We present the velocity measurements in electro-magnetic shock tube for beam interaction experiment by three methods; laser refraction, photodiode for self-emission, and high speed framing camera. The laser refraction showed that the average shock velocity was 6.7 km/s when the initial pressure was 1000 Pa and the initial charging voltage was 16 kV. The self-emissions from piston discharge plasma were measured by photodiodes and by high speed framing camera. The measurements showed that the duration between shock and piston was up to 8 microseconds with a 400-mm propagation in the shock tube, which is enough time as dissociation target for beam interaction experiment.The complementary velocity measurement is significant for understanding the electro-magnetically driven shock physics.

  17. Optimization of surface plasmon resonance experiments: Case of high mobility group box 1 (HMGB1) interactions.

    PubMed

    Anggayasti, Wresti L; Mancera, Ricardo L; Bottomley, Steven; Helmerhorst, Erik

    2016-04-15

    Surface plasmon resonance (SPR) is a powerful technique for evaluating protein-protein interactions in real time. However, inappropriately optimized experiments can often lead to problems in the interpretation of data, leading to unreliable kinetic constants and binding models. Optimization of SPR experiments involving "sticky" proteins, or proteins that tend to aggregate, represents a typical scenario where it is important to minimize errors in the data and the kinetic analysis of those data. This is the case of High Mobility Group Box 1 and the receptor of advanced glycation end products. A number of improvements in protein purification, buffer composition, immobilization conditions, and the choice of flow rate are shown to result in substantial improvements in the accurate characterization of the interactions of these proteins and the derivation of the corresponding kinetic constants. PMID:26869083

  18. Examination of air-sea CO2 fluxes from the low-latitude coastal Eastern Pacific: Application of predictive algorithms to new VOS observations.

    NASA Astrophysics Data System (ADS)

    Hales, B.; Alin, S.; Feely, R. A.; Hernandez-Ayon, M.; Letelier, R.; Strutton, P. G.; Cosca, C.

    2008-12-01

    Coastal oceans are regions of large and highly variable air-sea CO2 fluxes, leading to highly uncertain predictions of globally significant contributions to the atmospheric carbon budget. Estimates of net annual regional fluxes are often the balance between poorly-constrained, large-magnitude sinks and sources. This is the case for the Pacific coast of North America, where a recent synthesis (Chavez et al., 2007) predicted low total fluxes resulting from the near-cancellation of large, lightly-sampled fluxes of opposite sign. In particular, the low latitude coastal waters off Central America appeared to be a large source of CO2 to the atmosphere, but there was very low spatial and temporal observational coverage in these waters. Recently, new VOS data in this region has become available that has dramatically increased both spatial and temporal sampling density in this region. In previous work we developed a new remote sensing-based synthetic approach applied to the mid-latitude regions of the North American Pacific coast that gave strong predictive power and was subsequently validated by in-water measurements in the summer of 2007. We present the results of applying this predictive approach to the target study region, and the predictive relationship is then combined with seasonally resolved remote sensing data to generate annual net flux estimates and to evaluate the prediction of strong efflux from these low-latitude waters based on the sparse historical data.

  19. Interannual variability of the air-sea heat exchange in the western Mediterranean in relation to the deep-water formation processes

    NASA Astrophysics Data System (ADS)

    Soto, J.; Criado Aldeanueva, F.; García Lafuente, J.; Sanchez Román, A.; Carracedo, L.

    2009-04-01

    A 60-year long time series of heat fluxes (long and short wave radiation, sensible and latent contributions) from NCEP reanalysis dataset and a 22-year long time series of Sea Surface Temperature (SST) from JPL AVHRR Oceans Pathfinder dataset have been combined to study the seasonal and interannual variability of air-sea heat exchanges over the Mediterranean Sea and correlate them with the characteristics of the Mediterranean outflow through the Strait of Gibraltar collected in the frame of the INGRES projects in the last years. Special attention has been devoted to the historically reported deep-water formation basin of the Western Mediterranean (Gulf of Lions) during the pre-conditioning (November and December) and winter seasons. Until around 1970, no clear trend is found in the net heat flux winter series since positive and negative anomalies are observed alternatively. From then onwards, negative anomalies are frequently observed until the 2003-2006 positive events. A net heat loss of about 150 W/m2 is observed in 2005, the highest value since 1956, especially due to evaporation losses towards the atmosphere. The anomalously cold air and sea surface temperature in the area help to increase this contribution that reflects in a higher fraction of Western Mediterranean Deep Water (WMDW) in the outflow through the Strait.

  20. Inference of super-resolution ocean pCO2 and air-sea CO2 fluxes from non-linear and multiscale processing methods

    NASA Astrophysics Data System (ADS)

    Hernández-Carrasco, Ismael; Sudre, Joel; Garçon, Veronique; Yahia, Hussein; Dewitte, Boris; Garbe, Christoph; Illig, Séréna; Montes, Ivonne; Dadou, Isabelle; Paulmier, Aurélien; Butz, André

    2014-05-01

    In recent years the role of submesoscale activity is emerging as being more and more important to understand global ocean properties, for instance, for accurately estimating the sources and sinks of Greenhouse Gases (GHGs) at the air-sea interface. The scarcity of oceanographic cruises and the lack of available satellite products for GHG concentrations at high resolution prevent from obtaining a global assessment of their spatial variability at small scales. In this work we develop a novel method to reconstruct maps of CO2 fluxes at super resolution (4km) using SST and ocean colour data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). The responsible process for propagating the information between scales is related to cascading properties and multiscale organization, typical of fully developed turbulence. The methodology, based on the Microcanonical Multifractal Formalism, makes use, from the knowledge of singularity exponents, of the optimal wavelet for the determination of the energy injection mechanism between scales. We perform a validation analysis of the results of our algorithm using pCO2 ocean data from in-situ measurements in the upwelling region off Namibia.

  1. The European Fixed point Open Ocean Observatory network (FixO3): Multidisciplinary observations from the air-sea interface to the deep seafloor

    NASA Astrophysics Data System (ADS)

    Lampitt, Richard; Cristini, Luisa; Alexiou, Sofia

    2015-04-01

    The Fixed point Open Ocean Observatory network (FixO3, http://www.fixo3.eu/ ) integrates 23 European open ocean fixed point observatories and improves access to these infrastructures for the broader community. These provide multidisciplinary observations in all parts of the oceans from the air-sea interface to the deep seafloor. Started in September 2013 with a budget of 7 Million Euros over 4 years, the project has 29 partners drawn from academia, research institutions and SME's coordinated by the National Oceanography Centre, UK. Here we present the programme's achievements in the 18 months and the activities of the 12 Work Packages which have the objectives to: • integrate and harmonise the current procedures and processes • offer free access to observatory infrastructures to those who do not have such access, and free and open data services and products • innovate and enhance the current capability for multidisciplinary in situ ocean observation Open ocean observation is a high priority for European marine and maritime activities. FixO3 provides important data and services to address the Marine Strategy Framework Directive and in support of the European Integrated Maritime Policy. FixO3 provides a strong integrated framework of open ocean facilities in the Atlantic from the Arctic to the Antarctic and throughout the Mediterranean, enabling an integrated, regional and multidisciplinary approach to understand natural and anthropogenic change in the ocean.

  2. Characterization of DNA-protein interactions using high-throughput sequencing data from pulldown experiments

    NASA Astrophysics Data System (ADS)

    Moreland, Blythe; Oman, Kenji; Curfman, John; Yan, Pearlly; Bundschuh, Ralf

    Methyl-binding domain (MBD) protein pulldown experiments have been a valuable tool in measuring the levels of methylated CpG dinucleotides. Due to the frequent use of this technique, high-throughput sequencing data sets are available that allow a detailed quantitative characterization of the underlying interaction between methylated DNA and MBD proteins. Analyzing such data sets, we first found that two such proteins cannot bind closer to each other than 2 bp, consistent with structural models of the DNA-protein interaction. Second, the large amount of sequencing data allowed us to find rather weak but nevertheless clearly statistically significant sequence preferences for several bases around the required CpG. These results demonstrate that pulldown sequencing is a high-precision tool in characterizing DNA-protein interactions. This material is based upon work supported by the National Science Foundation under Grant No. DMR-1410172.

  3. Siple station experiments on wave-particle interactions in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Helliwell, R. A.

    1979-01-01

    Natural and controlled whistler-mode signals have been used to study nonlinear mechanisms of wave growth and wave-wave interactions (WWI) in the magnetosphere; three general classes of WWI (triggering, suppression, and entrainment) are identified and interpreted in terms of a model based on cyclotron resonance interaction. This model is also used to estimate the wave field intensity associated with different types of WWI. A new type of triggered emission, the band-limited impulse (BLI) is interpreted in terms of the switching of phase-bunched currents. In addition, an experiment to find a threshold for the excitation of the coherent wave instability is discussed, and observed VLF wave-induced transient bursts of X-rays, light and E-region ionization enhancements are considered with regard to a step function wave interacting with all resonant electrons in a given energy range.

  4. Search for neutrino oscillations in the MINOS experiment by using quasi-elastic interactions

    SciTech Connect

    Piteira, Rodolphe; /Paris U., VI-VII

    2005-09-01

    The enthusiasm of the scientific community for studying oscillations of neutrinos is equaled only by the mass of their detectors. The MINOS experiment determines and compares the near spectrum of muonic neutrinos from the NUMI beam to the far one, in order to measure two oscillation parameters: {Delta}m{sub 23}{sup 2} and sin{sup 2} (2{theta}{sub 23}). The spectra are obtained by analyzing the charged current interactions which difficulty lies in identifying the interactions products (e.g. muons). An alternative method identifying the traces of muons, bent by the magnetic field of the detectors, and determining their energies is presented in this manuscript. The sensitivity of the detectors is optimal for the quasi-elastic interactions, for which a selection method is proposed, to study their oscillation. Even though it reduces the statistics, such a study introduces fewer systematic errors, constituting the ideal method on the long range.

  5. Genetic Risk by Experience Interaction for Childhood Internalizing Problems: Converging Evidence across Multiple Methods

    PubMed Central

    Vendlinski, Matthew K.; Lemery-Chalfant, Kathryn; Essex, Marilyn J.; Goldsmith, H. Hill

    2010-01-01

    Background Identifying how genetic risk interacts with experience to predict psychopathology is an important step toward understanding the etiology of mental health problems. Few studies have examined genetic risk by experience interaction (GxE) in the development of childhood psychopathology. Methods We used both co-twin and parent mental health as markers of genetic risk to test whether GxE predicted internalizing problems in a sample of 8-year-old twins. Multi-instrument composites were used to characterize both parent and child psychopathology, and five experiential risk factors (socioeconomic status, single parent upbringing, negative parent-child interactions, number of negative life events, negative impact of negative life events) composed a cumulative risk index. Results We found consistent evidence for GxE for child internalizing problems, with significant interaction effects emerging both when genetic risk was indexed by co-twin mental health and when it was based on parent mental health. When co-twin mental health was used to estimate genetic risk, child internalizing problems were more heritable for children at low rather than high experiential risk. When parent mental health was used to estimate genetic risk, the association between genetic risk and internalizing problems was stronger for children at elevated experiential risk. Consideration of the interaction effect sizes helps to reconcile these findings. Conclusions Our results suggest that the processes involved in both diathesis-stress and bioecological models of development may operate for child internalizing problems. Effect sizes indicated that the main effects of genetic and experiential risk were much better predictors of child internalizing problems than was their interaction. PMID:21198591

  6. Spatial and temporal variability of heat, water vapor, carbon dioxide, and momentum air-sea exchange in a coastal environment

    NASA Astrophysics Data System (ADS)

    Crawford, Timothy L.; McMillen, Robert T.; Meyers, Tilden P.; Hicks, Bruce B.

    1993-07-01

    Simultaneous eddy correlation measurements from a tower, a boat, and an aircraft platform are used to assess the spatial and temporal variability of heat, moisture, momentum, and CO2 turbulent fluxes in a coastal environment. Dissolved CO2 in the coastal waters and atmospheric CO2 concentrations were continuously measured throughout the experiment. Good agreement was found among the different sensing systems. Air-to-sea gas, momentum, and energy flux density measurements are shown to be achievable from both a boat and an aircraft. The observed 10 W/sq m sensible heat flux was time-invariant but did not vary spatially with surface temperature, which was strongly correlated with ocean depth. The 100 to 200 W/sq m evaporative moisture flux dominated energy exchange and varied both in time and space. No consistent diurnal variation was observed, but the spatial trend also followed surface temperature. CO2 exchange exhibited large spatial and temporal variance.

  7. Effect of genes, social experience, and their interaction on the courtship behaviour of transgenic Drosophila males.

    PubMed

    Svetec, Nicolas; Houot, Benjamin; Ferveur, Jean-François

    2005-06-01

    Behaviour depends (a) on genes that specify the neural and non-neural elements involved in the perception of and responses to sensory stimuli and (b) on experience that can modulate the fine development of these elements. We exposed transgenic and control Drosophila melanogaster males, and their hybrids, to male siblings during adult development and measured the contribution of genes and of experience to their courtship behaviour. The transgene CheB42a specifically targets male gustatory sensillae and alters the perception of male inhibitory pheromones which leads to frequent male-male interactions. The age at which social experience occurred and the genotype of tester males induced a variable effect on the intensity of male homo- and heterosexual courtship. The strong interaction between the effects of genes and of social experience reveals the plasticity of the apparently stereotyped elements involved in male courtship behaviour. Finally, a high intensity of homosexual courtship was found only in males that simultaneously carried a mutation in their white gene and the CheB42a transgene. PMID:16174337

  8. A Study of Hadronic Weak Interaction - The n3He Experiment at SNS

    NASA Astrophysics Data System (ADS)

    Kabir, Latiful

    2015-10-01

    While parity violation (PV) is well-understood at the quark and lepton level, it is much more elusive in hadronic systems, being dominated by several orders of magnitude by the strong interaction. However, studies of PV in hadronic systems offer a unique probe of nucleon structure, complementary to other probes of low-energy non-perturbative QCD. The n3He experiment at the spallation neutron source at ORNL is motivated to probe the Hadronic Weak Interaction (HWI) by measuring the parity violating spin asymmetry of the recoil proton in the reaction n + 3He --> p +T +765 KeV. This is sensitive to ΔI = 0 and 1 components of the HWI, and is expected to be extremely small (of the order of 10-7). The experiment aims to determine this PV asymmetry with the statistical sensitivity of the order of 10-8. The experiment is now in the data taking phase and will continue until the end of the year. I will describe the experiment and give its current status.

  9. Interannual and seasonal variabilities in air-sea CO2 fluxes along the U.S. eastern continental shelf and their sensitivity to increasing air temperatures and variable winds

    NASA Astrophysics Data System (ADS)

    Cahill, Bronwyn; Wilkin, John; Fennel, Katja; Vandemark, Doug; Friedrichs, Marjorie A. M.

    2016-02-01

    Uncertainty in continental shelf air-sea CO2 fluxes motivated us to investigate the impact of interannual and seasonal variabilities in atmospheric forcing on the capacity of three shelf regions along the U.S. eastern continental shelf to act as a sink or source of atmospheric CO2. Our study uses a coupled biogeochemical-circulation model to simulate scenarios of "present-day" and "future-perturbed" mesoscale forcing variability. Overall, the U.S. eastern continental shelf acts as a sink for atmospheric CO2. There is a clear gradient in air-sea CO2 flux along the shelf region, with estimates ranging from -0.6 Mt C yr-1 in the South Atlantic Bight (SAB) to -1.0 Mt C yr-1 in the Mid-Atlantic Bight (MAB) and -2.5 Mt C yr-1 in the Gulf of Maine (GOM). These fluxes are associated with considerable interannual variability, with the largest interannual signal exhibited in the Gulf of Maine. Seasonal variability in the fluxes is also evident, with autumn and winter being the strongest CO2 sink periods and summer months exhibiting some outgassing. In our future-perturbed scenario spatial differences tend to cancel each other out when the fluxes are integrated over the MAB and GOM, resulting in only minor differences between future-perturbed and present-day air-sea CO2 fluxes. This is not the case in the SAB where the position of the along-shelf gradient shifts northward and the SAB becomes a source of CO2 to the atmosphere (0.7 Mt C yr-1) primarily in response to surface warming. Our results highlight the importance of temperature in regulating air-sea CO2 flux variability.

  10. The front line of social capital creation--a natural experiment in symbolic interaction.

    PubMed

    Patulny, Roger; Siminski, Peter; Mendolia, Silvia

    2015-01-01

    This paper offers theoretical and empirical contributions to understanding the micro-sociological processes behind the creation of social capital. Theoretically, we argue that the emotional and shared experience of participating in symbolic interaction rituals may affect social capital in four different ways, via: (i) a 'citizenship' effect, connecting participants symbolically to the broader, civic society; (ii) a 'supportive' effect, bonding participants with each other; (iii) an exclusive 'tribal' effect, which crowds-out connections with other groups and the wider society; and (iv) an 'atomising' effect, whereby intense experiences create mental health problems that damage social capital. We illustrate this with a case study of Australian veterans of the Vietnam War. The randomness of the National Service conscription lotteries of that era translates into a high-quality natural experiment. We formulate several hypotheses about which of the four effects dominates for veterans who participated in the 'symbolic interaction' of training and deployment. We test these hypotheses using data from the 2006 Australian Census of Population and Housing, and the NSW 45 & Up Study. We found that war service reduced 'bonding' social capital, but increased 'bridging' social capital, and this is not explained completely by mental health problems. This suggests that while the combined 'tribal' and 'atomizing' effects of service outweigh the 'supportive' effects, the 'citizenship' effect is surprisingly robust. Although they feel unsupported and isolated, veterans are committed to their community and country. These paradoxical findings suggest that social capital is formed through symbolic interaction. The emotional and symbolic qualities of interaction rituals may formulate non-strategic (perhaps irrational) connections with society regardless of the status of one's personal support networks. PMID:24836279

  11. Breaking waves and near-surface sea spray aerosol dependence on changing winds: Wave breaking efficiency and bubble-related air-sea interaction processes

    NASA Astrophysics Data System (ADS)

    Hwang, P. A.; Savelyev, I. B.; Anguelova, M. D.

    2016-05-01

    Simultaneous measurements of sea spray aerosol (SSA), wind, wave, and microwave brightness temperature are obtained in the open ocean on-board Floating Instrument Platform (FLIP). These data are analysed to clarify the ocean surface processes important to SSA production. Parameters are formulated to represent surface processes with characteristic length scales spanning a broad range. The investigation reveals distinct differences of the SSA properties in rising winds and falling winds, with higher SSA volume in falling winds. Also, in closely related measurements of whitecap coverage, higher whitecap fraction as a function of wind speed is found in falling winds than in rising winds or in older seas than in younger seas. Similar trend is found in the short scale roughness reflected in the microwave brightness temperature data. In the research of length and velocity scales of breaking waves, it has been observed that the length scale of wave breaking is shorter in mixed seas than in wind seas. For example, source function analysis of short surface waves shows that the characteristic length scale of the dissipation function shifts toward higher wavenumber (shorter wavelength) in mixed seas than in wind seas. Similarly, results from feature tracking or Doppler analysis of microwave radar sea spikes, which are closely associated with breaking waves, show that the magnitude of the average breaking wave velocity is smaller in mixed seas than in wind seas. Furthermore, breaking waves are observed to possess geometric similarity. Applying the results of breaking wave analyses to the SSA and whitecap observations described above, it is suggestive that larger air cavities resulting from the longer breakers are entrained in rising high winds. The larger air cavities escape rapidly due to buoyancy before they can be fully broken down into small bubbles for the subsequent SSA production or whitecap manifestation. In contrast, in falling winds (with mixed seas more likely), the shorter breaker entrains smaller and more numerous air cavities that stay underwater longer for more efficient bubble breakup by turbulence and prolonging the surface disturbances attributable to wave breaking. For low winds, the breaking scale is small and with high efficiency for SSA or whitecap generation; the trend of rising or falling wind is less important.

  12. A coupled decadal-scale air-sea interaction theory: the NAT-NAO-AMO-AMOC coupled mode and its global impacts

    NASA Astrophysics Data System (ADS)

    Li, Jianping; Sun, Cheng; Jin, Fei-Fei

    2016-04-01

    Observational analysis shows that the North Atlantic Oscillation (NAO) leads the oceanic Atlantic Multidecadal Oscillation (AMO) by 15-20 years and the latter also leads the former by around 15 years. The Community Climate System Model (CCSM) version 4 is employed to investigate the relevant mechanism in the linkage between the NAO and AMO. The results show that the positive North Atlantic Oscillation (NAO) forces the strengthening of the Atlantic meridional overturning circulation (AMOC) and induces a basin-wide uniform sea surface temperature (SST) warming that corresponds to the Atlantic multidecadal oscillation (AMO). The SST field exhibits a delayed response to the preceding enhanced AMOC, and shows a pattern similar to the North Atlantic tripole (NAT), with SST warming in the northern North Atlantic and cooling in the southern part. This SST pattern (negative NAT phase) may lead to an atmospheric response that resembles the negative NAO phase, and subsequently the oscillation proceeds, but in the opposite sense. This implies a NAO-AMO-AMOC coupled mode in decadal scale. Based on these mechanisms, a simple delayed oscillator model is established to explain the quasi-periodic multidecadal variability of the NAO. The magnitude of the NAO forcing of the AMOC/AMO and the time delay of the AMOC/AMO feedback are two key parameters of the delayed oscillator. For a given set of parameters, the quasi 60-year cycle of the NAO can be well predicted. This delayed oscillator model is useful for understanding of the oscillatory mechanism of the NAO, which has significant potential for decadal predictions as well as the interpretation of proxy data records. The NAT-NAO-AMO-AMOC coupled mode has important influences on global and regional climate. The twentieth century Northern Hemisphere mean surface temperature (NHT) is characterized by a multidecadal warming-cooling-warming pattern followed by a flat trend since about 2000 (recent warming hiatus). Here we demonstrate that the multidcadal variability in NHT including the recent warming hiatus is tied to the NAT-NAO-AMO-AMOC coupled mode and the NAO is implicated as a useful predictor of NHT multidecadal variability. An NAO-based linear model is therefore established to predict the NHT, which gives an excellent hindcast for NHT in 1971-2011 with the recent flat trend well predicted. NHT in 2012-2027 is predicted to fall slightly over the next decades, due to the recent NAO decadal weakening that temporarily offsets the anthropogenically induced warming. The subtropical eastern Australian rainfall (SEAR) shows evident fluctuations over decadal to multidecadal time scales and is connected to the NAO over decadal time scales, with the NAO leading by around 15 yr. The decadal-scale variability of SEAR is associated with the NAT-NAO-AMO-AMOC coupled mode which can have a delayed impact on SST fluctuations in the subpolar Southern Ocean (SO), and these SST changes could in turn contribute to the decadal variability in SEAR through their impacts on the Southern Hemisphere atmospheric circulation. A linear model for SEAR decadal variability was developed by combination of the NAO and Pacific decadal oscillation (PDO). The observed SEAR decadal variability is considerably well simulated by the linear model, and the relationship between the simulation and observation is stable. SEAR over the coming decade may increase slightly, because of the recent NAO weakening and the return of negative PDO phase.

  13. Tropical cyclogenesis in Eastern Atlantique: Impact of earlier passage of African Easterly Wave trough on the evolution of Mesoscale Convective Systems and air-sea interaction

    NASA Astrophysics Data System (ADS)

    Lahat Dieng, Abdou; Eymard, Laurence; Moustapha Sall, Saidou; Lazar, Alban; Leduc-Leballeur, Marion

    2014-05-01

    A large part of Atlantic tropical depressions is generated in the Eastern basin in relation with the African Easterly Waves and the Mesoscale Convective Systems coming from the African continent. But initial surface oceanic and atmosphere conditions favoring such evolution are largely unknown. This study analyzes the structures of strengthening and dissipating MCSs evolving near the West African coast and evaluates the role of the surface oceanic condition on their evolutions. Satellite brightness temperature from Meteosat Second Generation over the summer season of 2006 and radar data for the same season between 1993 and 1999 are used to subjectively select fourteen cases of strengthening (dissipating) MCSs when they cross the Senegalese coast. With these observed MCSs locations, a lagged composite analysis is then performed using Era interim and CFSR reanalyses. Results show that the strengthening MCS composite is preceded by prior passage of an AEW near the West African coast. This first trough wave was associated with a cyclonic circulation in the low and middle troposphere and has enhanced southwest wind flow behind him feeding humidly to the strengthening MCS composite which was located in the vicinity of the second AEW trough. The contraction of the wave length associated with the two troughs was probably facilitated this supply in humidity. The Sea Surface Temperature seem contribute to the MCS enhancement through surface evaporation flux but this contribution is less important than humidity advection by the fist system. These conditions were not found in the dissipating MCS case which dissipated in a drying environment air dominated by subsidence and anticyclonic circulation. Key words: Mesoscale Convective System, African Easterly Wave, Sea Surface Temperature, tropical depression.

  14. Measuring air-sea gas-exchange velocities in a large-scale annular wind-wave tank

    NASA Astrophysics Data System (ADS)

    Mesarchaki, E.; Kräuter, C.; Krall, K. E.; Bopp, M.; Helleis, F.; Williams, J.; Jähne, B.

    2015-01-01

    In this study we present gas-exchange measurements conducted in a large-scale wind-wave tank. Fourteen chemical species spanning a wide range of solubility (dimensionless solubility, α = 0.4 to 5470) and diffusivity (Schmidt number in water, Scw = 594 to 1194) were examined under various turbulent (u10 = 0.73 to 13.2 m s-1) conditions. Additional experiments were performed under different surfactant modulated (two different concentration levels of Triton X-100) surface states. This paper details the complete methodology, experimental procedure and instrumentation used to derive the total transfer velocity for all examined tracers. The results presented here demonstrate the efficacy of the proposed method, and the derived gas-exchange velocities are shown to be comparable to previous investigations. The gas transfer behaviour is exemplified by contrasting two species at the two solubility extremes, namely nitrous oxide (N2O) and methanol (CH3OH). Interestingly, a strong transfer velocity reduction (up to a factor of 3) was observed for the relatively insoluble N2O under a surfactant covered water surface. In contrast, the surfactant effect for CH3OH, the high solubility tracer, was significantly weaker.

  15. The interaction of early life experiences with COMT val158met affects anxiety sensitivity.

    PubMed

    Baumann, C; Klauke, B; Weber, H; Domschke, K; Zwanzger, P; Pauli, P; Deckert, J; Reif, A

    2013-11-01

    The pathogenesis of anxiety disorders is considered to be multifactorial with a complex interaction of genetic factors and individual environmental factors. Therefore, the aim of this study was to examine gene-by-environment interactions of the genes coding for catechol-O-methyltransferase (COMT) and monoamine oxidase A (MAOA) with life events on measures related to anxiety. A sample of healthy subjects (N = 782; thereof 531 women; mean age M = 24.79, SD = 6.02) was genotyped for COMT rs4680 and MAOA-uVNTR (upstream variable number of tandem repeats), and was assessed for childhood adversities [Childhood Trauma Questionnaire (CTQ)], anxiety sensitivity [Anxiety Sensitivity Index (ASI)] and anxious apprehension [Penn State Worry Questionnaire (PSWQ)]. Main and interaction effects of genotype, environment and gender on measures related to anxiety were assessed by means of regression analyses. Association analysis showed no main gene effect on either questionnaire score. A significant interactive effect of childhood adversities and COMT genotype was observed: Homozygosity for the low-active met allele and high CTQ scores was associated with a significant increment of explained ASI variance [R(2) = 0.040, false discovery rate (FDR) corrected P = 0.04]. A borderline interactive effect with respect to MAOA-uVNTR was restricted to the male subgroup. Carriers of the low-active MAOA allele who reported more aversive experiences in childhood exhibited a trend for enhanced anxious apprehension (R(2) = 0.077, FDR corrected P = 0.10). Early aversive life experiences therefore might increase the vulnerability to anxiety disorders in the presence of homozygosity for the COMT 158met allele or low-active MAOA-uVNTR alleles. PMID:24118915

  16. Differential effects of intranasal oxytocin on sexual experiences and partner interactions in couples.

    PubMed

    Behnia, Behnoush; Heinrichs, Markus; Bergmann, Wiebke; Jung, Stefanie; Germann, Janine; Schedlowski, Manfred; Hartmann, Uwe; Kruger, Tillmann H C

    2014-03-01

    Knowledge about the effects of the neuropeptide oxytocin (OXT) on human sexual behaviors and partner interactions remains limited. Based on our previous studies, we hypothesize that OXT should be able to positively influence parameters of sexual function and couple interactions. Employing a naturalistic setting involving 29 healthy heterosexual couples (n=58 participants), we analyzed the acute effects of intranasally administered OXT (24IU) on sexual drive, arousal, orgasm and refractory aspects of sexual behavior together with partner interactions. Data were assessed by psychometric instruments (Acute Sexual Experiences Scale, Arizona Sexual Experience Scale) as well as biomarkers, such as cortisol, α-amylase and heart rate. Intranasal OXT administration did not alter "classical" parameters of sexual function, such as sexual drive, arousal or penile erection and lubrication. However, analysis of variance and a hierarchical linear model (HLM) revealed specific effects related to the orgasmic/post-orgasmic interval as well as parameters of partner interactions. According to HLM analysis, OXT increased the intensity of orgasm, contentment after sexual intercourse and the effect of study participation. According to ANOVA analysis, these effects were more pronounced in men. Men additionally indicated higher levels of sexual satiety after sexual intercourse with OXT administration. Women felt more relaxed and subgroups indicated better abilities to share sexual desires or to empathize with their partners. The effect sizes were small to moderate. Biomarkers indicated moderate psychophysiological activation but were not affected by OXT, gender or method of contraception. Using a naturalistic setting, intranasal OXT administration in couples exerted differential effects on parameters of sexual function and partner interactions. These results warrant further investigations, including subjects with sexual and relationship problems. PMID:24503174

  17. Investigating lava-substrate interactions through flow experiments with syrup, wax, and molten basalt

    NASA Astrophysics Data System (ADS)

    Rumpf, M. E.; Lev, E.

    2015-12-01

    Among the many factors influencing the complex process of lava flow emplacement, the interaction with the substrate onto which flow is emplaced plays a central role. Lava flows are rarely emplaced onto smooth or regular surfaces. For example, at Kīlauea Volcano, Hawai'i, lava flows regularly flow over solid rock, vegetation, basaltic or silica sand, and man-made materials, including asphalt and concrete. In situ studies of lava-substrate interactions are inherently difficult, and often dangerous, to carry-out, requiring the design of controllable laboratory experiments. We investigate the effects of substrate grain size, cohesion, and roughness on flow mobility and morphology through a series of flow experiments using analog materials and molten basalt. We have developed a series of experiments that allow for adjustable substrate parameters and analyze their effects on lava flow emplacement. The first set of experiments are performed at the Fluids Mechanics Laboratory at the Lamont-Doherty Earth Observatory and focus on two analog materials: polyethylene glycol (PEG), a commercially available wax, and corn syrup. The fluids were each extruded onto a series of scaled substrate beds to replicate the emplacement of lava in a natural environment. Preliminary experiments demonstrated that irregular topography, particularly topography with a height amplitude similar to that of the flow itself, can affect flow morphology, width, and velocity by acting as local barriers or culverts to the fluid. This is expected from observations of fluid flow in natural environments. A follow-up set of experiments will be conducted in Fall 2015 at the Syracuse University (SU) Lava Project Lab. In this set, we will pour molten basalt directly onto a series of substrates representing natural environments found on the Earth and other rocky bodies in the Solar System. These experiments will allow for analysis of the effects of basaltic composition and high temperatures on lava-substrate heat

  18. Studies of particle interactions in bubble chamber, spark chambers and counter experiments. Annual progress report

    SciTech Connect

    Holloway, L.E.; O'Halloran, T.A. Jr.; Simmons, R.O.

    1983-07-01

    During the past six years we have carried out and planned experiments which predominantly studied the production and decay of particles containing charmed quarks. A series of photoproduction and neutron production experiments started with the very early observation of the production of J/psi by neutrons and by photons at Fermilab. From subsequent experiments using these neutral beams and the basic detecting system, we have reported results on the photoproduction of the ..lambda../sub c/ charmed baryon and the D and D* charmed mesons. More recent runs are studying the high energy photoproduction of vector mesons including the psi'. The present experiment in this sequence is using neutrons to produce a large number of D mesons. Another series of experiments at Fermilab set out to study the hadronic production of charmed mesons. The Chicago Cyclotron facility was modified with a detector sensitive to various possible production mechanisms. The experiments were a success; clean signals of D mesons were observed to be produced by pions, and also the production of chi/sub c/ with the subsequent decay via a ..gamma..-ray to psi was observed. The charmonium experiments run this year have better photon resolution for measuring the decays of chi/sub c/ to psi. We are part of a collaboration which is working on the Collider Detector Facility for Fermilab. The CDF at Fermilab is a possible source of (weak) intermediate vector bosons from the collisions of protons and anti-protons. Our responsibilities in the CDF include both the construction of the muon detector and the designing, planning, and testing of the FASTBUS electronics. The second part of our weak interaction program is the Neutrino Oscillation experiment which is now under construction at Brookhaven.

  19. The experience of agency in human-computer interactions: a review

    PubMed Central

    Limerick, Hannah; Coyle, David; Moore, James W.

    2014-01-01

    The sense of agency is the experience of controlling both one’s body and the external environment. Although the sense of agency has been studied extensively, there is a paucity of studies in applied “real-life” situations. One applied domain that seems highly relevant is human-computer-interaction (HCI), as an increasing number of our everyday agentive interactions involve technology. Indeed, HCI has long recognized the feeling of control as a key factor in how people experience interactions with technology. The aim of this review is to summarize and examine the possible links between sense of agency and understanding control in HCI. We explore the overlap between HCI and sense of agency for computer input modalities and system feedback, computer assistance, and joint actions between humans and computers. An overarching consideration is how agency research can inform HCI and vice versa. Finally, we discuss the potential ethical implications of personal responsibility in an ever-increasing society of technology users and intelligent machine interfaces. PMID:25191256

  20. Spectral function in electro-weak interactions and its impact on neutrino oscillation experiments

    SciTech Connect

    Jen, C.-M.

    2015-10-15

    Neutrino oscillation experiments have entered the high-precision era in the last few years. The oscillation parameters, as a measure of the neutrino properties, are extracted from the energy-dependent oscillation probability function. Different types of nuclear dynamics deeply influence the determination of neutrino energies in neutrino oscillation experiments. As a consequence, a comprehensive understanding of various nuclear dynamics interprets the scenario behind the neutrino interaction with nucleus and nuclei. The initial ground-state structure of the target nucleus is categorized in one typical nuclear dynamics, and its realistic description is generally referred as the spectral function (SF). Implementing the SF for each target nucleus into the GENIE neutrino event generator is the preliminary step necessary to obtain a reliable determination of the kinematics of all detectable final-products from neutrino interactions. At the intermedium-range of neutrino energies (∼ 1 GeV), the kinematic energy reconstruction is the vastly used approach and consists in identifying final-products as coming from the charged-current quasi-elastic-like (CCQE-like) neutrino interactions.

  1. Triadic social interactions operate across time: a field experiment with wild chimpanzees

    PubMed Central

    Wittig, Roman M.; Crockford, Catherine; Langergraber, Kevin E.; Zuberbühler, Klaus

    2014-01-01

    Social animals cooperate with bonding partners to outcompete others. Predicting a competitor's supporter is likely to be beneficial, regardless of whether the supporting relationship is stable or transient, or whether the support happens immediately or later. Although humans make such predictions frequently, it is unclear to what extent animals have the cognitive abilities to recognize others’ transient bond partners and to predict others' coalitions that extend beyond the immediate present. We conducted playback experiments with wild chimpanzees to test this. About 2 h after fighting, subjects heard recordings of aggressive barks of a bystander, who was or was not a bond partner of the former opponent. Subjects looked longer and moved away more often from barks of the former opponents’ bond partners than non-bond partners. In an additional experiment, subjects moved away more from barks than socially benign calls of the same bond partner. These effects were present despite differences in genetic relatedness and considerable time delays between the two events. Chimpanzees, it appears, integrate memories of social interactions from different sources to make inferences about current interactions. This ability is crucial for connecting triadic social interactions across time, a requirement for predicting aggressive support even after a time delay. PMID:24500174

  2. Spectral function in electro-weak interactions and its impact on neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Jen, C.-M.

    2015-10-01

    Neutrino oscillation experiments have entered the high-precision era in the last few years. The oscillation parameters, as a measure of the neutrino properties, are extracted from the energy-dependent oscillation probability function. Different types of nuclear dynamics deeply influence the determination of neutrino energies in neutrino oscillation experiments. As a consequence, a comprehensive understanding of various nuclear dynamics interprets the scenario behind the neutrino interaction with nucleus and nuclei. The initial ground-state structure of the target nucleus is categorized in one typical nuclear dynamics, and its realistic description is generally referred as the spectral function (SF). Implementing the SF for each target nucleus into the GENIE neutrino event generator is the preliminary step necessary to obtain a reliable determination of the kinematics of all detectable final-products from neutrino interactions. At the intermedium-range of neutrino energies (˜ 1 GeV), the kinematic energy reconstruction is the vastly used approach and consists in identifying final-products as coming from the charged-current quasi-elastic-like (CCQE-like) neutrino interactions.

  3. Shifts of neutrino oscillation parameters in reactor antineutrino experiments with non-standard interactions

    NASA Astrophysics Data System (ADS)

    Li, Yu-Feng; Zhou, Ye-Ling

    2014-11-01

    We discuss reactor antineutrino oscillations with non-standard interactions (NSIs) at the neutrino production and detection processes. The neutrino oscillation probability is calculated with a parametrization of the NSI parameters by splitting them into the averages and differences of the production and detection processes respectively. The average parts induce constant shifts of the neutrino mixing angles from their true values, and the difference parts can generate the energy (and baseline) dependent corrections to the initial mass-squared differences. We stress that only the shifts of mass-squared differences are measurable in reactor antineutrino experiments. Taking Jiangmen Underground Neutrino Observatory (JUNO) as an example, we analyze how NSIs influence the standard neutrino measurements and to what extent we can constrain the NSI parameters. Long baseline reactor antineutrino experiments, such as KamLAND [10,11]. The aim of these experiments is to observe the slow oscillation with Δ21 and measure the corresponding oscillation parameters Δm212 and θ12. Short baseline reactor antineutrino experiments, such as Daya Bay [1-3], Double CHOOZ [4], RENO [5]. They are designed to observe the fast oscillation with Δ31 and Δ32 (or equivalently, Δee[3]) and measure the corresponding oscillation parameters Δmee2, θ13. Medium baseline reactor antineutrino experiments. They stand for the next generation experiments of reactor antineutrinos, with typical representatives of Jiangmen Underground Neutrino Observatory (JUNO) [12] and RENO-50 [13]. They can determine the neutrino mass ordering (m1experiments. High-dimensional operators originating from new physics can contribute to the neutrino oscillation in the form of non-standard interactions (NSIs) [14

  4. Analysis of helicopter downwash/frigate airwake interaction using statistically designed experiments

    NASA Astrophysics Data System (ADS)

    Nacakli, Yavuz

    A research program to investigate helicopter downwash/frigate airwake interaction has been initiated using a statistically robust experimental program featuring Design of Experiments. Engineering analysis of the helicopter/frigate interface is complicated by the fact that two flowfields become inherently coupled as separation distance decreases. The final objective of this work is to develop experimental methods to determine when computer simulations need to include the effects of a coupled flowfield versus using a simplified representation by superposing the velocity fields of the individual flowfields. The work presented was performed in the Old Dominion University Low Speed Wind Tunnel using a simplified 1/50 scale frigate waterline model and traverse mounted powered rotor with thrust measurement. Particle Image Velocimetry (PIV) velocity surveys were used with rotor thrust coefficient measurements at locations of identified interaction to help understand the underlying flow physics. Initially, PIV surveys of the frigate model landing deck in isolation and the rotor in isolation were performed to provide a baseline flow understanding. Next a designed experiment was devised yielding a response model for thrust coefficient as a function of vertical and longitudinal distance from the hangar door (base of the step), both with and without the rotor. This first experiment showed that thrust coefficient could be measured with enough precision to identify changes due to location using an advance ratio of 0.075 (Vinfinity = 5.14 m/s and o = 5000 rpm). A second designed experiment determined the practical spatial resolution for mapping the thrust coefficient response along the frigate's longitudinal center plane. Finally, a third designed experiment directly compared rotor thrust measurements between airwake and no-airwake cases and successfully identified regions that differed with statistical significance. Lastly, a qualitative comparison study was performed to

  5. Evaluation of quality of experience in interactive 3D visualization: methodology and results

    NASA Astrophysics Data System (ADS)

    Tourancheau, Sylvain; Sjöström, Mårten; Olsson, Roger; Persson, Anders; Ericson, Thomas

    2012-03-01

    Human factors are of high importance in 3D visualization, but subjective evaluation of 3D displays is not easy because of a high variability among users. This study aimed to evaluate and compare two different 3D visualization systems (a market stereoscopic display, and a state-of-the-art multi-view display) in terms of user performance and quality of experience (QoE), in the context of interactive visualization. An adapted methodology has been designed in order to focus on 3D differences and to reduce the influence of all other factors. Thirty-six subjects took part in an experiment during which they were asked to judge the quality of their experience, according to specific features. Results showed that a scene understanding and precision was significantly better on the multi-view display. Concerning the quality of experience, visual comfort was judged significantly better on the multi-view display and visual fatigue was reported by 52% of the subjects on the stereoscopic display. This study has permitted to identify some factors influencing QoE such as prior experience and stereopsis threshold.

  6. Epistemic asymmetries in psychotherapy interaction: therapists' practices for displaying access to clients' inner experiences.

    PubMed

    Weiste, Elina; Voutilainen, Liisa; Peräkylä, Anssi

    2016-05-01

    The relationship between a psychotherapist and a client involves a specific kind of epistemic asymmetry: in therapy sessions the talk mainly concerns the client's experience, which is unavailable, as such, to the therapist. This epistemic asymmetry is understood in different ways within different psychotherapeutic traditions. Drawing on a corpus of 70 audio-recorded sessions of cognitive psychotherapy and psychoanalysis and using the method of conversation analysis, the interactional practices of therapists for dealing with this epistemic asymmetry are investigated. Two types of epistemic practices were found to be employed by therapists while formulating and interpreting the client's inner experience. In the formulations, the therapists and clients co-described the client's experience, demonstrating that the client's inner experience was somewhat similarly available to both participants. In the interpretations, the therapists constructed an evidential foundation for the interpretation by summarising the client's talk and using the same descriptive terms as the client. Clients held therapists accountable for this epistemic work: if they failed to engage in such work, their right to know the client's inner experience was called into question. PMID:26574238

  7. Engineering aspect of the microwave ionosphere nonlinear interaction experiment (MINIX) with a sounding rocket

    NASA Astrophysics Data System (ADS)

    Nagatomo, Makoto; Kaya, Nobuyuki; Matsumoto, Hiroshi

    The Microwave Ionosphere Nonlinear Interaction Experiment (MINIX) is a sounding rocket experiment to study possible effects of strong microwave fields in case it is used for energy transmission from the Solar Power Satellite (SPS) upon the Earth's atmosphere. Its secondary objective is to develop high power microwave technology for space use. Two rocket-borne magnetrons were used to emit 2.45 GHz microwave in order to make a simulated condition of power transmission from an SPS to a ground station. Sounding of the environment radiated by microwave was conducted by the diagnostic package onboard the daughter unit which was separated slowly from the mother unit. The main design drivers of this experiment were to build such high power equipments in a standard type of sounding rocket, to keep the cost within the budget and to perform a series of experiments without complete loss of the mission. The key technology for this experiment is a rocket-borne magnetron and high voltage converter. Location of position of the daughter unit relative to the mother unit was a difficult requirement for a spin-stabilized rocket. These problems were solved by application of such a low cost commercial products as a magnetron for microwave oven and a video tape recorder and camera.

  8. Laboratory experiments to study supersonic astrophysical flows interacting with clumpy environments

    NASA Astrophysics Data System (ADS)

    Rosen, P. A.; Foster, J. M.; Wilde, B. H.; Hartigan, P.; Blue, B. E.; Hansen, J. F.; Sorce, C.; Williams, R. J. R.; Coker, R.; Frank, A.

    2009-08-01

    A wide variety of objects in the universe drive supersonic outflows through the interstellar medium which is often highly clumpy. These inhomogeneities affect the morphology of the shocks that are generated. The hydrodynamics are difficult to model as the problem is inherently 3D and the clumps are subject to a variety of fluid instabilities as they are accelerated and destroyed by the shock. Over the last two years, we have been carrying out experiments at the University of Rochester’s Omega laser to address the interaction of a dense-plasma jet with a localised density perturbation. More recently, we have turned our attention to the interaction of a shock wave with a spherical particle. We use a 1.6-mm diameter, 1.2-mm length Omega hohlraum to drive a composite plastic ablator (which includes bromine to prevent M-band radiation from preheating the experiment). The ablator acts as a “piston” driving a shock into 0.3 g cm-3 foam containing a 0.5-mm diameter sapphire sphere. We radiograph along two orthogonal lines of sight, using nickel or zinc pinhole-apertured X-ray backlighters, to study the subsequent hydrodynamics. We present initial experimental results and two-dimensional simulations of the experiment.

  9. Laboratory experiments to study supersonic astrophysical flows interacting with clumpy environments

    NASA Astrophysics Data System (ADS)

    Rosen, P. A.; Foster, J. M.; Wilde, B. H.; Coker, R.; Blue, B. E.; Williams, R. J. R.; Hansen, F.; Sorce, C.; Hartigan, P.; Carver, R.; Palmer, J.

    2007-11-01

    A wide variety of objects in the universe drive supersonic outflows through the interstellar medium which is often highly clumpy. These inhomogeneities affect the morphology of the shocks that are generated. The hydrodynamics is difficult to model as the problem is inherently 3D and the clumps are subject to a variety of fluid instabilities as they are accelerated and destroyed by the shock. Over the last two years, we have been carrying out experiments on the University of Rochester's Omega laser to address the interaction of a dense-plasma jet with a localized density perturbation. More recently, we have turned our attention to the interaction of a shock wave with a spherical particle. We use a 1.6-mm diameter, 1.2-mm length Omega hohlraum to drive a composite plastic ablator (which includes bromine to prevent M-band radiation from preheating the experiment). The ablator acts as a ``piston'' driving a shock into 0.3 g/cc foam containing a 0.5-mm diameter sapphire sphere. We radiograph along two orthogonal lines of sight, using nickel or zinc pinhole-apertured x-ray backlighters, to study the subsequent hydrodynamics. We present initial experimental results and multi-dimensional simulations of the experiment.

  10. Laboratory experiments to study supersonic astrophysical flows interacting with clumpy environments

    NASA Astrophysics Data System (ADS)

    Rosen, Paula; Foster, J. M.; Williams, R. J. R.; Wilde, B. H.; Coker, R.; Hartigan, P.; Carver, R.; Palmer, J.; Blue, B. E.; Hansen, F.; Sorce, C.; Frank, A.

    2008-04-01

    A wide variety of objects in the universe drive supersonic outflows through the interstellar medium which is often highly clumpy. These inhomogeneities affect the morphology of the shocks that are generated. The hydrodynamics is difficult to model as the problem is inherently 3D and the clumps are subject to a variety of fluid instabilities as they are accelerated and destroyed by the shock. Over the last two years, we have been carrying out experiments on the Omega laser to address the interaction of a dense-plasma jet with a localized density perturbation. More recently, we have turned our attention to the interaction of a shock wave with a spherical particle. We use a 1.6-mm diameter, 1.2-mm length hohlraum to drive a composite plastic ablator (which includes bromine to prevent M-band radiation from preheating the experiment). The ablator acts as a ``piston'' driving a shock into 0.3 g/cc foam containing a 0.5-mm diameter sapphire sphere. We radiograph along two orthogonal lines of sight, using nickel or zinc pinhole-apertured x-ray backlighters, to study the subsequent hydrodynamics. We present initial experimental results and multi-dimensional simulations of the experiment.

  11. Playing in or out of character: user role differences in the experience of interactive storytelling.

    PubMed

    Roth, Christian; Vermeulen, Ivar; Vorderer, Peter; Klimmt, Christoph; Pizzi, David; Lugrin, Jean-Luc; Cavazza, Marc

    2012-11-01

    Interactive storytelling (IS) is a promising new entertainment technology synthesizing preauthored narrative with dynamic user interaction. Existing IS prototypes employ different modes to involve users in a story, ranging from individual avatar control to comprehensive control over the virtual environment. The current experiment tested whether different player modes (exerting local vs. global influence) yield different user experiences (e.g., senses of immersion vs. control). A within-subject design involved 34 participants playing the cinematic IS drama "Emo Emma"( 1 ) both in the local (actor) and in global (ghost) mode. The latter mode allowed free movement in the virtual environment and hidden influence on characters, objects, and story development. As expected, control-related experiential qualities (effectance, autonomy, flow, and pride) were more intense for players in the global (ghost) mode. Immersion-related experiences did not differ over modes. Additionally, men preferred the sense of command facilitated by the ghost mode, whereas women preferred the sense of involvement facilitated by the actor mode. PMID:23017117

  12. Interactions between above- and belowground organisms modified in climate change experiments

    NASA Astrophysics Data System (ADS)

    Stevnbak, Karen; Scherber, Christoph; Gladbach, David J.; Beier, Claus; Mikkelsen, Teis N.; Christensen, Søren

    2012-11-01

    Climate change has been shown to affect ecosystem process rates and community composition, with direct and indirect effects on belowground food webs. In particular, altered rates of herbivory under future climate can be expected to influence above-belowground interactions. Here, we use a multifactor, field-scale climate change experiment and independently manipulate atmospheric CO2 concentration, air and soil temperature and drought in all combinations since 2005. We show that changes in these factors modify the interaction between above- and belowground organisms. We use an insect herbivore to experimentally increase aboveground herbivory in grass phytometers exposed to all eight combinations of climate change factors for three years. Aboveground herbivory increased the abundance of belowground protozoans, microbial growth and microbial nitrogen availability. Increased CO2 modified these links through a reduction in herbivory and cascading effects through the soil food web. Interactions between CO2, drought and warming can affect belowground protozoan abundance. Our findings imply that climate change affects aboveground-belowground interactions through changes in nutrient availability.

  13. Kinetically driven Raman scattering in short, bi-speckle laser-plasma interaction experiments

    NASA Astrophysics Data System (ADS)

    Glize, Kevin; Rousseaux, Christophe; Baton, Sophie; Dervieux, Vincent; Lancia, Livia

    2015-11-01

    In order to investigate collective speckles behavior in laser-plasma interaction, bi-speckle experiments have been performed using the ELFIE facility (LULI). Two independent laser pulses (1.06 nm, 1.5 ps FWHM) interact with preformed He plasma (0.06 nc, 300 eV). The first beam drives stimulated Raman scattering, while the second, which its intensity is set near SRS threshold, is focused near the first one (typically 90 μm). The interaction, with crossed and parallel polarization, was studied for both variation of the time delay and the lateral distance between the two pulses, featuring a highly resolved Thomson-scattering diagnostic and backward Raman imaging. It is shown that the kinetic perturbations are of primary importance on triggering SRS in the weak speckle, which exhibits SRS instability up to an expectedly long time delay after the interaction of the strong one. The experimental results will be discussed with the help of 2D PIC simulations (CALDER code).

  14. EXOS-B/Siple Station VLF wave-particle interaction experiment

    NASA Technical Reports Server (NTRS)

    Kimura, I.; Matsumoto, H.; Hashimoto, K.; Mukai, T.; Helliwell, R. A.; Bell, T. F.; Inan, U. S.; Katsufrakis, J. P.

    1981-01-01

    Preliminary results of experiments made using the EXOS-B satellite to make simultaneous observations of VLF signals transmitted from Siple Station, Antarctica and interacting particles are reported. VLF measurements carried out by the EXOS-B wideband receiver upon satellite crossings of the Siple meridian at equatorial and high latitudes were able to detect the Siple signal on about 50% of the passes, and observed four instances of artificially stimulated emissions. Two of these cases exhibit triggering with a clear relation to the transmitted frequency format, while in the remaining two this relation is absent. Electron fluxes at energies from 3 eV to 9.5 keV are observed to be enhanced during the Siple stimulated emission events, with a distribution on the equatorial passes sufficient to satisfy the cyclotron interaction condition for parallel propagation of Siple signals of frequency about half the local cyclotron frequency.

  15. SAmBA: an interactive software for optimizing the design of biological macromolecules crystallization experiments.

    PubMed

    Audic, S; Lopez, F; Claverie, J M; Poirot, O; Abergel, C

    1997-10-01

    SAmBA is a new software for the design of minimal experimental protocols using the notion of orthogonal arrays of strength 2. The main application of SAmBA is the search of protein crystallization conditions. Given a user input defining the relevant effectors/variables (e.g., pH, temperature, salts) and states (e.g., pH: 5, 6, 7 and 8), this software proposes an optimal set of experiments in which all tested variables and the pairwise interactions between them are symmetrically sampled. No a priori restrictions on the number and range of experimental variables is imposed. SAmBA consists of two complementary programs, SAm and BA, using a simulated annealing approach and a backtracking algorithm, respectively. The software is freely available as C code or as an interactive JAVA applet at http:/(/)igs-server.cnrs-mrs.fr. PMID:9329089

  16. Air-Sea CO2 fluxes and NEP changes in a Baja California Coastal Lagoon during the anomalous North Pacific warm condition in 2014

    NASA Astrophysics Data System (ADS)

    Ávila López, M. D. C.; Martin Hernandez-Ayon, J. M.; Camacho-Ibar, V.; Sandoval Gil, J.; Mejía-Trejo, A.; Félix-Bermudez, A.; Pacheco-Ruiz, I.

    2015-12-01

    The present study examines the temporal variability of seawater carbonate chemistry and air-sea CO2 fluxes (FCO2) in a Baja California Mediterranean-climate coastal lagoon. This study was carried out from Nov-2013 to Nov-2014, a period in which anomalous warm conditions were present in the North Pacific Ocean influenced the local oceanography in the adjacent coastal waters off Baja California. These ocean conditions resulted on a negative anomaly of upwelling index, which led to summer-like season (weak upwelling condition) that could be observed in the response of carbon dynamics and metabolic status in San Quintín Bay. Minor changes in dissolved inorganic carbon (DIC) concentration during spring months (~100 µmol kg-1) where observed and were associated to biological processes within the lagoon. High DIC (~2200 µmol kg-1), pCO2 (~800 μatm), and minimum pH (~7.8) values were observed in summer, reflecting the predominance of respiration processes apparently mostly linked to the remineralization of sedimentary organic matter supplied from macroalgal blooms. San Quintín Bay acted as a weak source of CO2 to the atmosphere during the study period, with maximum value observed in July (~10 mmol C m-2 d-1). Temporal biomass production of macroalgae contributed to about 50% of total FCO2 estimated in spring-summer seasons, that was a potencial internal source of organic matter to fuel respiration processes in San Quintín Bay. Eelgrass metabolism contributes in a lower degree in total FCO2. During the anomalous ocean conditions in 2014, the lagoon switched seasonally between net heterotrophy and net autotrophy during the study period, where photosynthesis and respiration processes in the lagoon were closer to a balance. Whole-system metabolism and FCO2 clearly indicated the strong dependence of San Quintín Bay on upwelling conditions and benthic metabolism activity, which was mainly controlled by dominant primary producer communities.

  17. A diagram of wind speed versus air-sea temperature difference to understand the dynamics of the marine atmospheric boundary layer off northwest Europe

    NASA Astrophysics Data System (ADS)

    Kettle, Anthony

    2015-04-01

    Wind speed and atmospheric stability have an important role in determining the turbulence in the marine atmospheric boundary layer (MABL) as well as the surface wave field. The understanding of MABL dynamics in northwest Europe is complicated by fetch effects, the proximity of coastlines, shallow topography, and larger scale circulation patterns (e.g., cold air outbreaks). Numerical models have difficulty simulating the marine atmospheric boundary layer in coastal areas and partially enclosed seas, and this is partly due to spatial resolution problems at land-sea coastline discontinuities. In these offshore environments, the boundary layer processes are often best understood directly from time series measurements from measurement platforms or buoys, in spite of potential difficulties from platform flow distortion as well as the spatial sparseness of the data sets. This contribution presents updated results of measurements from offshore platforms in the North Sea and Norwegian Sea in terms of a summary diagnostic - wind speed versus air-sea temperature difference (U-ΔT) - with important implications for understanding atmospheric boundary layer processes. The U-ΔT diagram was introduced in earlier surveys of data from coastal and offshore sites in northwest Europe to summarize boundary layer conditions at a given location. Additional information from a series of measurement purpose-built offshore measurement and oil/gas production platforms from the North Sea illustrates how the wind characteristics vary spatially over large distances. The results are important for the offshore wind industry because of the way that wind turbines accrue fatigue damage in different conditions of atmospheric stability and wind speed.

  18. Effect of gas-transfer-velocity parameterization choice on CO2 air-sea fluxes in the North Atlantic and European Arctic

    NASA Astrophysics Data System (ADS)

    Wróbel, I.; Piskozub, J.

    2015-11-01

    The ocean sink is an important part of the anthropogenic CO2 budget. Because the terrestrial biosphere is usually treated as a residual, understanding the uncertainties the net flux into the ocean sink is crucial for understanding the global carbon cycle. One of the sources of uncertainty is the parameterization of CO2 gas transfer velocity. We used a recently developed software tool, FluxEngine, to calculate monthly net carbon air-sea flux for the extratropical North Atlantic, European Arctic as well as global values (or comparison) using several available parameterizations of gas transfer velocity of different dependence of wind speed, both quadratic and cubic. The aim of the study is to constrain the uncertainty caused by the choice of parameterization in the North Atlantic, a large sink of CO2 and a region with good measurement coverage, characterized by strong winds. We show that this uncertainty is smaller in the North Atlantic and in the Arctic than globally, within 5 % in the North Atlantic and 4 % in the European Arctic, comparing to 9 % for the World Ocean when restricted to functions with quadratic wind dependence and respectively 42, 40 and 67 % for all studied parameterizations. We propose an explanation of this smaller uncertainty due to the combination of higher than global average wind speeds in the North Atlantic and lack of seasonal changes in the flux direction in most of the region. We also compare the available pCO2 climatologies (Takahashi and SOCAT) pCO2 discrepancy in annual flux values of 8 % in the North Atlantic and 19 % in the European Arctic. The seasonal flux changes in the Arctic have inverse seasonal change in both climatologies, caused most probably by insufficient data coverage, especially in winter.

  19. Southern Ocean air-sea heat flux, SST spatial anomalies, and implications for multi-decadal upper ocean heat content trends.

    NASA Astrophysics Data System (ADS)

    Tamsitt, V. M.; Talley, L. D.; Mazloff, M. R.

    2014-12-01

    The Southern Ocean displays a zonal dipole (wavenumber one) pattern in sea surface temperature (SST), with a cool zonal anomaly in the Atlantic and Indian sectors and a warm zonal anomaly in the Pacific sector, associated with the large northward excursion of the Malvinas and southeastward flow of the Antarctic Circumpolar Current (ACC). To the north of the cool Indian sector is the warm, narrow Agulhas Return Current (ARC). Air-sea heat flux is largely the inverse of this SST pattern, with ocean heat gain in the Atlantic/Indian, cooling in the southeastward-flowing ARC, and cooling in the Pacific, based on adjusted fluxes from the Southern Ocean State Estimate (SOSE), a ⅙° eddy permitting model constrained to all available in situ data. This heat flux pattern is dominated by turbulent heat loss from the ocean (latent and sensible), proportional to perturbations in the difference between SST and surface air temperature, which are maintained by ocean advection. Locally in the Indian sector, intense heat loss along the ARC is contrasted by ocean heat gain of 0.11 PW south of the ARC. The IPCC AR5 50 year depth-averaged 0-700 m temperature trend shows surprising similarities in its spatial pattern, with upper ocean warming in the ARC contrasted by cooling to the south. Using diagnosed heat budget terms from the most recent (June 2014) 6-year run of the SOSE we find that surface cooling in the ARC is balanced by heating from south-eastward advection by the current whereas heat gain in the ACC is balanced by cooling due to northward Ekman transport driven by strong westerly winds. These results suggest that spatial patterns in multi-decadal upper ocean temperature trends depend on regional variations in upper ocean dynamics.

  20. Search for weakly interacting massive particles with the Cryogenic Dark Matter Search experiment

    NASA Astrophysics Data System (ADS)

    Saab, Tarek

    From individual galaxies, to clusters of galaxies, to in between the cushions of your sofa, Dark Matter appears to be pervasive on every scale. With increasing accuracy, recent astrophysical measurements, from a variety of experiments, are arriving at the following cosmological model: a flat cosmology (Ωk = 0) with matter and energy densities contributing roughly 1/3 and 2/3 (Ωm = 0.35, ΩΛ = 0.65). Of the matter contribution, it appears that only ≈10% (Ωb ≈ 0.04) is attributable to baryons. Astrophysical measurements constrain the remaining matter to be non-realtivistic, interacting primarily gravitationally. Various theoretical models for such Dark Matter exist. A leading candidate for the non-baryonic matter are Weakly Interacting Massive Particles (dubbed WIMPS). These particles, and their relic density may be naturally explained within the framework of Super-Symmetry theories. Super-Symmetry also offers predictions as to the scattering rates of WIMPS with baryonic matter allowing for the design and tailoring of experiments that search specifically for the WIMPs. The Cryogenic Dark Matter Search experiment is searching for evidence of WIMP interactions in crystals of Ge and Si. Using cryogenic detector technology to measure both the phonon and ionization response to a particle recoil the CDMS detectors are able to discriminate between electron and nuclear recoils, thus reducing the large rates of electron recoil backgrounds to levels with which a Dark Matter search is not only feasible, but far-reaching. This thesis will describe in some detail the physical principles behind the CDMS detector technology, highlighting the final step in the evolution of the detector design and characterization techniques. In addition, data from a 100 day long exposure of the current run at the Stanford Underground Facility will be presented, with focus given to detector performance as well as to the implications on allowable WIMP mass-cross- section parameter space.

  1. Synoptic evaluation of carbon cycling in the Beaufort Sea during summer: contrasting river inputs, ecosystem metabolism and air-sea CO2 fluxes

    NASA Astrophysics Data System (ADS)

    Forest, A.; Coupel, P.; Else, B.; Nahavandian, S.; Lansard, B.; Raimbault, P.; Papakyriakou, T.; Gratton, Y.; Fortier, L.; Tremblay, J.-É.; Babin, M.

    2014-05-01

    The accelerated decline in Arctic sea ice and an ongoing trend toward more energetic atmospheric and oceanic forcings are modifying carbon cycling in the Arctic Ocean. A critical issue is to understand how net community production (NCP; the balance between gross primary production and community respiration) responds to changes and modulates air-sea CO2 fluxes. Using data collected as part of the ArcticNet-Malina 2009 expedition in the southeastern Beaufort Sea (Arctic Ocean), we synthesize information on sea ice, wind, river, water column properties, metabolism of the planktonic food web, organic carbon fluxes and pools, as well as air-sea CO2 exchange, with the aim of documenting the ecosystem response to environmental changes. Data were analyzed to develop a non-steady-state carbon budget and an assessment of NCP against air-sea CO2 fluxes. During the field campaign, the mean wind field was a mild upwelling-favorable wind (~ 5 km h-1) from the NE. A decaying ice cover (< 80% concentration) was observed beyond the shelf, the latter being fully exposed to the atmosphere. We detected some areas where the surface mixed layer was net autotrophic owing to high rates of primary production (PP), but the ecosystem was overall net heterotrophic. The region acted nonetheless as a sink for atmospheric CO2, with an uptake rate of -2.0 ± 3.3 mmol C m-2 d-1 (mean ± standard deviation associated with spatial variability). We attribute this discrepancy to (1) elevated PP rates (> 600 mg C m-2 d-1) over the shelf prior to our survey, (2) freshwater dilution by river runoff and ice melt, and (3) the presence of cold surface waters offshore. Only the Mackenzie River delta and localized shelf areas directly affected by upwelling were identified as substantial sources of CO2 to the atmosphere (> 10 mmol C m-2 d-1). Daily PP rates were generally < 100 mg C m-2 d-1 and cumulated to a total PP of ~ 437.6 × 103 t C for the region over a 35-day period. This amount was about twice the

  2. Nonlinear soil-structure interaction calculations simulating the SIMQUAKE experiment using STEALTH 2D

    NASA Technical Reports Server (NTRS)

    Tang, H. T.; Hofmann, R.; Yee, G.; Vaughan, D. K.

    1980-01-01

    Transient, nonlinear soil-structure interaction simulations of an Electric Power Research Institute, SIMQUAKE experiment were performed using the large strain, time domain STEALTH 2D code and a cyclic, kinematically hardening cap soil model. Results from the STEALTH simulations were compared to identical simulations performed with the TRANAL code and indicate relatively good agreement between all the STEALTH and TRANAL calculations. The differences that are seen can probably be attributed to: (1) large (STEALTH) vs. small (TRANAL) strain formulation and/or (2) grid discretization differences.

  3. Comparison of hydrodynamic model of graphene with recent experiment on measuring the Casimir interaction

    NASA Astrophysics Data System (ADS)

    Klimchitskaya, G. L.; Mostepanenko, V. M.

    2015-01-01

    We obtain the reflection coefficients from a graphene sheet deposited on a material substrate under a condition that graphene is described by the hydrodynamic model. Using these coefficients, the gradient of the Casimir force in the configuration of a recent experiment is calculated in the framework of the Lifshitz theory. It is shown that the hydrodynamic model is excluded by the measurement data at a 99% confidence level over a wide range of separations. From the fact that the same data are in very good agreement with theoretical predictions of the Dirac model of graphene, the low-energy character of the Casimir interaction is confirmed.

  4. Pushing the Limits of Plasma Length in Inertial-Fusion Laser-Plasma Interaction Experiments

    NASA Astrophysics Data System (ADS)

    Froula, D. H.; Divol, L.; London, R. A.; Michel, P.; Berger, R. L.; Meezan, N. B.; Neumayer, P.; Ross, J. S.; Wallace, R.; Glenzer, S. H.

    2008-01-01

    We demonstrate laser beam propagation and low backscatter in laser produced hohlraum plasmas of ignition plasma length. At intensities I<5×1014Wcm-2 greater than 80% of the energy in a blue (3ω, 351 nm) laser is transmitted through a L=5-mm long, high-temperature (Te=2.5keV), high-density (ne=5×1020cm-3) plasma. These experiments show that the backscatter scales exponentially with plasma length which is consistent with linear theory. The backscatter calculated by a new steady state 3D laser-plasma interaction code developed for large ignition plasmas is in good agreement with the measurements.

  5. The Experience of Force: The Role of Haptic Experience of Forces in Visual Perception of Object Motion and Interactions, Mental Simulation, and Motion-Related Judgments

    ERIC Educational Resources Information Center

    White, Peter A.

    2012-01-01

    Forces are experienced in actions on objects. The mechanoreceptor system is stimulated by proximal forces in interactions with objects, and experiences of force occur in a context of information yielded by other sensory modalities, principally vision. These experiences are registered and stored as episodic traces in the brain. These stored…

  6. Experiences with nonlinear dynamics of panels and membranes considering fluid-structure interaction and acoustic fatigue

    SciTech Connect

    Ferman, M.A.

    1994-12-31

    A collection of some highlights of the Author`s experiences with nonlinear dynamics in analyses and tests of Panels and Membranes encountered over the past 40 years is given. The primary focus is placed on a major block of his work since the early 70`s, involving work with fluid-structure interaction with Panels and Membranes, and with efforts in Acoustic Fatigue of Panels. While the Author had encountered nonlinear problems throughout Ins career involving flutter, vibration in general, and dynamic thrust instability; it was the more recent work with panels and membranes that greatly expanded his experience. This was triggered by the advent of highly maneuverable aircraft, powered by large powerful, noisy engines, and new materials in the mid 70`s. The significance of nonlinearity for these applications is most obvious from the results shown here-it simply cannot be ignored for optimal, safe design.

  7. Non-standard interactions in propagation at the Deep Underground Neutrino Experiment

    NASA Astrophysics Data System (ADS)

    Coloma, Pilar

    2016-03-01

    We study the sensitivity of current and future long-baseline neutrino oscillation experiments to the effects of dimension six operators affecting neutrino propagation through Earth, commonly referred to as Non-Standard Interactions (NSI). All relevant parameters entering the oscillation probabilities (standard and non-standard) are considered at once, in order to take into account possible cancellations and degeneracies between them. We find that the Deep Underground Neutrino Experiment will significantly improve over current constraints for most NSI parameters. Most notably, it will be able to rule out the so-called LMA-dark solution, still compatible with current oscillation data, and will be sensitive to off-diagonal NSI parameters at the level of ɛ ˜ {O} (0.05 - 0.5). We also identify two degeneracies among standard and non-standard parameters, which could be partially resolved by combining T2HK and DUNE data.

  8. Investigation of fracture-matrix interaction: Preliminary experiments in a simple system

    SciTech Connect

    Foltz, S.D.; Tidwell, V.C.; Glass, R.J.; Sobolik, S.R.

    1992-12-31

    Paramount to the modeling of unsaturated flow and transport through fractured porous media is a clear understanding of the processes controlling fracture-matrix interaction. As a first step toward such an understanding, two preliminary experiments have been performed to investigate the influence of matrix imbibition on water percolation through unsaturated fractures in the plane normal to the fracture. Test systems consisted of thin slabs of either tuff or an analog material cut by a single vertical fracture into which a constant fluid flux was introduced. Transient moisture content and solute concentration fields were imaged by means of x-ray absorption. Flow fields associated with the two different media were significantly different owing to differences in material properties relative to the imposed flux. Richards` equation was found to be a valid means of modeling the imbibition of water into the tuff matrix from a saturated fracture for the current experiment.

  9. Non-Standard Interactions in propagation at the Deep Underground Neutrino Experiment

    DOE PAGESBeta

    Coloma, Pilar

    2016-03-03

    Here, we study the sensitivity of current and future long-baseline neutrino oscillation experiments to the effects of dimension six operators affecting neutrino propagation through Earth, commonly referred to as Non-Standard Interactions (NSI). All relevant parameters entering the oscillation probabilities (standard and non-standard) are considered at once, in order to take into account possible cancellations and degeneracies between them. We find that the Deep Underground Neutrino Experiment will significantly improve over current constraints for most NSI parameters. Most notably, it will be able to rule out the so-called LMA-dark solution, still compatible with current oscillation data, and will be sensitive to off-diagonal NSI parameters at the level of ε ~more » $$ \\mathcal{O} $$ (0.05 – 0.5). We also identify two degeneracies among standard and non-standard parameters, which could be partially resolved by combining T2HK and DUNE data.« less

  10. Experiments on Interaction of Quasiparticles with Two-Level-Systems in a Superconducting Phase Qubit

    NASA Astrophysics Data System (ADS)

    Bilmes, Alexander; Lisenfeld, Jürgen; Heimes, Andreas; Zanker, Sebastian; Schön, Gerd; Ustinov, Alexey

    2015-03-01

    Two-Level-Systems (TLS) are one of the main sources of decoherence in superconducting qubits. Some individual and coherent TLS, present in the tunnel barrier of the qubit's Josephson junction, can be coherently operated via the qubit. In the past, experiments on superconducting glasses indicated that quasiparticles may give rise to TLS energy loss similar to Korringa relaxation. We will present experiments in which we use a phase qubit to explore the interaction of single TLS with non-equilibrium quasiparticles. We have implemented in-situ quasiparticle injection by using an on-chip dc-SQUID that is pulse-biased beyond its critical current. The quasiparticle density is calibrated by measuring associated characteristic changes to the qubit resonance frequency and energy relaxation rate. The coherence times of individual TLS is measured in dependence of the non-equilibrium quasiparticle density and compared to thermally generated quasiparticles. PI, KIT, Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany.

  11. An Innovation Teaching Experience Following Guidelines of European Space of Higher Education in the Interactive Learning

    NASA Astrophysics Data System (ADS)

    Zamorano, M.; Rodríguez, M. L.; Ramos-Ridao, A. F.; Pasadas, M.; Priego, I.

    The Area of Environmental Technology in Department of Civil Engineering has developed an innovation education project, entitled Application of new Information and Communication Technologies in Area of Environmental Technology teaching, to create a Web site that benefits both parties concerned in teaching-learning process, teachers and students. Here teachers conduct a supervised teaching and students have necessary resources to guide their learning process according to their capacities and possibilities. The project has also included a pilot experience to introduce European Space of Higher Education (ESHE) new teaching concept based on student's work, in one subject of Environmental Science degree, considering interactive learning complementary to presence teaching. The experience has showed strength and weakness of the method and it is the beginning in a gradual process to guide e-learning education in future.

  12. A Novel Time of Flight Detector for the Pioneering High Energy Nuclear Interaction eXperiment

    NASA Astrophysics Data System (ADS)

    Dix, Richard; Drummond, Kirk; Powell, William; Chiu, Mickey

    2010-11-01

    Time-of Flight (TOF) detectors allow one to identify particles created in collider experiments. The Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory is proposing new forward timing detectors to measure the TOF with a 10 picosecond (ps) timing resolution. A prototype of the detector electronics system was tested by using Cherenkov signals from cosmic rays and translating them into digital signals. Each signal was split and delivered to two analog-to-digital-converters (ADCs). C++ and ROOT were used to write programs to compare voltage readings reported by the two ADC channels and determine the time difference between them, which was 76 ps. Using new ADCs, which run 17 times faster, the timing resolution will be 5 ps. This will allow PHENIX to probe the meson-baryon anomaly at intermediate, transverse momentum by making detailed measurements in a psuedorapidity region which has not been well measured.

  13. Electron beam-plasma interaction experiments with the Versatile Toroidal Facility (VTF)

    SciTech Connect

    Murphy, S.M.; Lee, M.C.; Moriarty, D.T.; Riddolls, R.J.

    1995-12-31

    The laboratory investigation of electron beam-plasma interactions is motivated by the recent space shuttle experiments. Interesting but puzzling phenomena were observed in the shuttle experiments such as the bulk heating of background ionospheric plasmas by the injected electron beams and the excitation of plasma waves in the frequency range of ELF waves. The plasma machine, the Versatile Toroidal Facility (VTF) can generate a large magnetized plasma with the electron plasma frequency greater than the electron gyrofrequency by a factor of 3--5 similar to the plasma condition in the ionosphere. Short pulses of electron beams are injected into the VTF plasmas in order to simulate the beam injection from spacecrafts in the ionosphere. A Langmuir probe installed at a bottom port of VTF monitors the spatial variation of electron beams emitted from LaB6 filaments. An energy analyzer has been used to determine the particle energy distribution in the VTF plasmas. Several mechanisms will be tested as potential causes of the bulk heating of background plasmas by the injected electron beams as seen in the space shuttle experiments. It is speculated that the observed ELF emissions result from the excitation of purely growing modes detected by the space shuttle-borne detectors. Results of the laboratory experiments will be reported to corroborate this speculation.

  14. Subjective evaluation of user experience in interactive 3D visualization in a medical context

    NASA Astrophysics Data System (ADS)

    Tourancheau, Sylvain; Sjöström, Mårten; Olsson, Roger; Persson, Anders; Ericson, Thomas; Rudling, Johan; Norén, Bengt

    2012-02-01

    New display technologies enable the usage of 3D-visualization in a medical context. Even though user performance seems to be enhanced with respect to 2D thanks to the addition of recreated depth cues, human factors, and more particularly visual comfort and visual fatigue can still be a bridle to the widespread use of these systems. This study aimed at evaluating and comparing two different 3D visualization systems (a market stereoscopic display, and a state-of-the-art multi-view display) in terms of quality of experience (QoE), in the context of interactive medical visualization. An adapted methodology was designed in order to subjectively evaluate the experience of users. 14 medical doctors and 15 medical students took part in the experiment. After solving different tasks using the 3D reconstruction of a phantom object, they were asked to judge their quality of the experience, according to specific features. They were also asked to give their opinion about the influence of 3D-systems on their work conditions. Results suggest that medical doctors are opened to 3D-visualization techniques and are confident concerning their beneficial influence on their work. However, visual comfort and visual fatigue are still an issue of 3D-displays. Results obtained with the multi-view display suggest that the use of continuous horizontal parallax might be the future response to these current limitations.

  15. Tropical climate variability: interactions across the Pacific, Indian, and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Kajtar, Jules B.; Santoso, Agus; England, Matthew H.; Cai, Wenju

    2016-06-01

    Complex interactions manifest between modes of tropical climate variability across the Pacific, Indian, and Atlantic Oceans. For example, the El Niño-Southern Oscillation (ENSO) extends its influence on modes of variability in the tropical Indian and Atlantic Oceans, which in turn feed back onto ENSO. Interactions between pairs of modes can alter their strength, periodicity, seasonality, and ultimately their predictability, yet little is known about the role that a third mode plays. Here we examine the interactions and relative influences between pairs of climate modes using ensembles of 100-year partially coupled experiments in an otherwise fully coupled general circulation model. In these experiments, the air-sea interaction over each tropical ocean basin, as well as pairs of ocean basins, is suppressed in turn. We find that Indian Ocean variability has a net damping effect on ENSO and Atlantic Ocean variability, and conversely they each promote Indian Ocean variability. The connection between the Pacific and the Atlantic is most clearly revealed in the absence of Indian Ocean variability. Our model runs suggest a weak damping influence by Atlantic variability on ENSO, and an enhancing influence by ENSO on Atlantic variability.

  16. Interaction experiments using thin-foil-discharge warm-dense plasma

    NASA Astrophysics Data System (ADS)

    Hasegawa, Jun; Hirai, Satoshi; Katagiri, Ken; Yonaha, Masanao; Fukuda, Hitoshi; Oguri, Yoshiyuki; Ogawa, Masao; Murakami, Takeshi

    2007-07-01

    We developed a thin-foil-discharge (TFD) plasma target for beam-plasma interaction experiments. A discharge current of several tens of kilo-amperes rapidly heated and ionized a thin aluminum foil of sub- to several micrometers thick. The target areal density seen by projectiles was expected to be almost constant during several hundred nanoseconds from the ignition of the discharge because the size of the thin foil was chosen to be much larger than the cross-section of the incident beam. The optical observation of the plasma using a fast framing camera showed that the TFD plasma expanded one-dimensionally in the early stage of the discharge. We determined the plasma density and temperature from the observed plasma thickness and the deposited electrical power with equation-of-state data. A one-dimensional plasma expansion model was developed and used to examine the expected plasma parameters under various initial conditions. We also performed beam-plasma interaction experiments with fully stripped ions of 4.3 MeV/u. The energy loss of silicon ions was measured as a function of time by the TOF method.

  17. High Time-resolution Studies of RF Interaction Experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Sheerin, J. P.; Wood, M. R.; Adham, N.; Roe, R. G.; Gerres, J. M.; Watkins, B. J.; Bristow, W. A.; Spaleta, J.; Bernhardt, P. A.; Selcher, C. A.

    2010-12-01

    The high power HAARP HF transmitter is employed to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. Diagnostics included the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, and HF receivers to record stimulated electromagnetic emissions (SEE). Dependence of diagnostic signals on HAARP HF parameters, including pulselength, duty-cycle, aspect angle, and frequency were recorded. Short pulse, low duty cycle experiments demonstrate control of artificial field-aligned irregularities (AFAI) and isolation of ponderomotive effects. Among the effects observed and studied are: SLT spectra including cascade, collapse, and co-existence spectra and an outshifted plasma line under certain ionospheric conditions. High time resolution studies of the temporal evolution of the plasma line reveal the appearance of an overshoot effect on ponderomotive timescales. Bursty turbulence is observed in the collapse and cascade lines. Plasma line spectra exhibit a marked dependence on aspect angle with the strongest interaction region observed displaced southward of the HF zenith pointing angle. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  18. Air sea rescue, telemedicine style.

    PubMed

    Ferguson, J; Aujla, K; Pedley, D; Palombo, A

    2002-01-01

    Historically, requests from shipping in UK coastal waters for emergency medical advice have been handled on an ad hoc basis by various accident and emergency departments on behalf of the Coastguard. A formal contract to provide this service has recently been established with the Aberdeen Royal Infirmary in Scotland and the Royal Alexandra Hospital in Portsmouth, England. A pre-contract audit showed that the involvement of medical professionals in the evacuation decision improved the quality of triage and intervention. The medical staff at both hospitals received training in giving medical advice and the level of medical knowledge that could reasonably be expected of ships crews. Providing advice to commercial airlines developed from the maritime service. In association with a private company, staff at the Aberdeen Royal Infirmary have developed procedures to support cabin crew and medical professionals on board (initial figures suggest that a medical professional is present on about 45% of flights). At present, although there are insufficient data to draw any firm conclusions, it appears that up to two-thirds of diversions could be avoided using this service. PMID:12217123

  19. Numerical and laboratory experiments on the dynamics of plume-ridge interaction. Progress report

    SciTech Connect

    Kincaid, C.; Gable, C.W.

    1995-09-01

    Mantle plumes and passive upwelling beneath ridges are the two dominant modes of mantle transport and thermal/chemical fluxing between the Earth`s deep interior and surface. While plumes and ridges independently contribute to crustal accretion, they also interact and the dispersion of plumes within the upper mantle is strongly modulated by mid-ocean ridges. The simplest mode of interaction, with the plume centered on the ridge, has been well documented and modeled. The remaining question is how plumes and ridges interact when the plume is located off-axis; it has been suggested that a pipeline-like flow from the off-axis plume to the ridge axis at the base of the rigid lithosphere may develop. Mid-ocean ridges migrating away from hot mantle plumes can be affected by plume discharges over long times and ridge migration distances. Salient feature of this model is that off-axis plumes communicate with the ridge through a channel resulting from the refraction and dispersion of an axi-symmetric plume conduit along the base of the sloping lithosphere. To test the dynamics of this model, a series of numerical and laboratory dynamic experiments on the problem of a fixed ridge and an off-axis buoyant upwelling were conducted. Results are discussed.

  20. Inhalation experiments with mixtures of hydrocarbons. Experimental design, statistics and interpretation of kinetics and possible interactions.

    PubMed

    Eide, I; Zahlsen, K

    1996-01-01

    The paper describes experimental and statistical methods for toxicokinetic evaluation of mixtures in inhalation experiments. Synthetic mixtures of three C9 n-paraffinic, naphthenic and aromatic hydrocarbons (n-nonane, trimethylcyclohexane and trimethylbenzene, respectively) were studied in the rat after inhalation for 12h. The hydrocarbons were mixed according to principles for statistical experimental design using mixture design at four vapour levels (75, 150, 300 and 450 ppm) to support an empirical model with linear, interaction and quadratic terms (Taylor polynome). Immediately after exposure, concentrations of hydrocarbons were measured by head space gas chromatography in blood, brain, liver, kidneys and perirenal fat. Multivariate data analysis and modelling were performed with PLS (projections to latent structures). The best models were obtained after removing all interaction terms, suggesting that there were no interactions between the hydrocarbons with respect to absorption and distribution. Uptake of paraffins and particularly aromatics is best described by quadratic models, whereas the uptake of the naphthenic hydrocarbons is nearly linear. All models are good, with high correlation (r2) and prediction properties (Q2), the latter after cross validation. The concentrations of aromates in blood were high compared to the other hydrocarbons. At concentrations below 250 ppm, the naphthene reached higher concentrations in the brain compared to the paraffin and the aromate. Statistical experimental design, multivariate data analysis and modelling have proved useful for the evaluation of synthetic mixtures. The principles may also be used in the design of liquid mixtures, which may be evaporated partially or completely. PMID:8740533

  1. Cancer patients’ experiences of using an Interactive Health Communication Application (IHCA)

    PubMed Central

    Grimsbø, Gro H.; Engelsrud, Gunn H.; Ruland, Cornelia M.

    2012-01-01

    Interactive Health Communication Applications (IHCAs) are increasingly used in health care. Studies document that IHCAs provide patients with knowledge and social support, enhance self- efficacy and can improve behavioural and clinical outcomes. However, research exploring patients’ experiences of using IHCAs has been scarce. The aim of this study was to explore cancer patients’ perspectives and experiences related to the use of an IHCA called WebChoice in their homes. Qualitative interviews were conducted with infrequent, medium and frequent IHCA users—six women and four men with breast and prostate cancer. The interviews were transcribed and analyzed inspired by interactionistic perspectives. We found that some patients’ perceived WebChoice as a “friend,” others as a “stranger.” Access to WebChoice stimulated particularly high frequency users to position themselves as “information seeking agents,” assuming an active patient role. However, to position oneself as an “active patient” was ambiguous and emotional. Feelings of “calmness”, “normalization of symptoms”, feelings of “being part of a community”, feeling “upset” and “vulnerable”, as well as “feeling supported” were identified. Interaction with WebChoice implied for some users an increased focus on illness. Our findings indicate that the interaction between patients and an IHCA such as WebChoice occurs in a variety of ways, some of which are ambivalent or conflicting. Particularly for frequent and medium frequency users, it offers support, but may at the same time reinforce an element of uncertainty in their life. Such insights should be taken into consideration in the future development of IHCAs in healthcare in general and in particular for implementation into patients’ private sphere. PMID:22582085

  2. Enrichment experiment changes microbial interactions in an ultra-oligotrophic environment

    PubMed Central

    Ponce-Soto, Gabriel Y.; Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E.; Elser, James J.; Lee, Zarraz M.-P.; Souza, Valeria

    2015-01-01

    The increase of nutrients in water bodies, in particular nitrogen (N) and phosphorus (P) due to the recent expansion of agricultural and other human activities is accelerating environmental degradation of these water bodies, elevating the risk of eutrophication and reducing biodiversity. To evaluate the ecological effects of the influx of nutrients in an oligotrophic and stoichiometrically imbalanced environment, we performed a replicated in situ mesocosm experiment. We analyzed the effects of a N- and P-enrichment on the bacterial interspecific interactions in an experiment conducted in the Cuatro Cienegas Basin (CCB) in Mexico. This is a desert ecosystem comprised of several aquatic systems with a large number of microbial endemic species. The abundance of key nutrients in this basin exhibits strong stoichiometric imbalance (high N:P ratios), suggesting that species diversity is maintained mostly by competition for resources. We focused on the biofilm formation and antibiotic resistance of 960 strains of cultivated bacteria in two habitats, water and sediment, before and after 3 weeks of fertilization. The water habitat was dominated by Pseudomonas, while Halomonas dominated the sediment. Strong antibiotic resistance was found among the isolates at time zero in the nutrient-poor bacterial communities, but resistance declined in the bacteria isolated in the nutrient-rich environments, suggesting that in the nutrient-poor original environment, negative inter-specific interactions were important, while in the nutrient-rich environments, competitive interactions are not so important. In water, a significant increase in the percentage of biofilm-forming strains was observed for all treatments involving nutrient addition. PMID:25883593

  3. Enrichment experiment changes microbial interactions in an ultra-oligotrophic environment.

    PubMed

    Ponce-Soto, Gabriel Y; Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E; Elser, James J; Lee, Zarraz M-P; Souza, Valeria

    2015-01-01

    The increase of nutrients in water bodies, in particular nitrogen (N) and phosphorus (P) due to the recent expansion of agricultural and other human activities is accelerating environmental degradation of these water bodies, elevating the risk of eutrophication and reducing biodiversity. To evaluate the ecological effects of the influx of nutrients in an oligotrophic and stoichiometrically imbalanced environment, we performed a replicated in situ mesocosm experiment. We analyzed the effects of a N- and P-enrichment on the bacterial interspecific interactions in an experiment conducted in the Cuatro Cienegas Basin (CCB) in Mexico. This is a desert ecosystem comprised of several aquatic systems with a large number of microbial endemic species. The abundance of key nutrients in this basin exhibits strong stoichiometric imbalance (high N:P ratios), suggesting that species diversity is maintained mostly by competition for resources. We focused on the biofilm formation and antibiotic resistance of 960 strains of cultivated bacteria in two habitats, water and sediment, before and after 3 weeks of fertilization. The water habitat was dominated by Pseudomonas, while Halomonas dominated the sediment. Strong antibiotic resistance was found among the isolates at time zero in the nutrient-poor bacterial communities, but resistance declined in the bacteria isolated in the nutrient-rich environments, suggesting that in the nutrient-poor original environment, negative inter-specific interactions were important, while in the nutrient-rich environments, competitive interactions are not so important. In water, a significant increase in the percentage of biofilm-forming strains was observed for all treatments involving nutrient addition. PMID:25883593

  4. Can Students Learn From Lecture Demonstrations?: The Role and Place of Interactive Lecture Experiments in Large Introductory Science Courses

    ERIC Educational Resources Information Center

    Milner-Bolotin, Marina; Kotlicki, Andrzej; Rieger, Georg

    2007-01-01

    In this article we describe a case study of interactive lecture experiments in a large introductory physics course. The impact of this pedagogy on student learning and motivation is also discussed. (Contains 1 table and 3 figures.)

  5. Robust Optimal Design of Experiments for Model Discrimination Using an Interactive Software Tool

    PubMed Central

    Stegmaier, Johannes; Skanda, Dominik; Lebiedz, Dirk

    2013-01-01

    Mathematical modeling of biochemical processes significantly contributes to a better understanding of biological functionality and underlying dynamic mechanisms. To support time consuming and costly lab experiments, kinetic reaction equations can be formulated as a set of ordinary differential equations, which in turn allows to simulate and compare hypothetical models in silico. To identify new experimental designs that are able to discriminate between investigated models, the approach used in this work solves a semi-infinite constrained nonlinear optimization problem using derivative based numerical algorithms. The method takes into account parameter variabilities such that new experimental designs are robust against parameter changes while maintaining the optimal potential to discriminate between hypothetical models. In this contribution we present a newly developed software tool that offers a convenient graphical user interface for model discrimination. We demonstrate the beneficial operation of the discrimination approach and the usefulness of the software tool by analyzing a realistic benchmark experiment from literature. New robust optimal designs that allow to discriminate between the investigated model hypotheses of the benchmark experiment are successfully calculated and yield promising results. The involved robustification approach provides maximally discriminating experiments for the worst parameter configurations, which can be used to estimate the meaningfulness of upcoming experiments. A major benefit of the graphical user interface is the ability to interactively investigate the model behavior and the clear arrangement of numerous variables. In addition to a brief theoretical overview of the discrimination method and the functionality of the software tool, the importance of robustness of experimental designs against parameter variability is demonstrated on a biochemical benchmark problem. The software is licensed under the GNU General Public License

  6. Robust optimal design of experiments for model discrimination using an interactive software tool.

    PubMed

    Stegmaier, Johannes; Skanda, Dominik; Lebiedz, Dirk

    2013-01-01

    Mathematical modeling of biochemical processes significantly contributes to a better understanding of biological functionality and underlying dynamic mechanisms. To support time consuming and costly lab experiments, kinetic reaction equations can be formulated as a set of ordinary differential equations, which in turn allows to simulate and compare hypothetical models in silico. To identify new experimental designs that are able to discriminate between investigated models, the approach used in this work solves a semi-infinite constrained nonlinear optimization problem using derivative based numerical algorithms. The method takes into account parameter variabilities such that new experimental designs are robust against parameter changes while maintaining the optimal potential to discriminate between hypothetical models. In this contribution we present a newly developed software tool that offers a convenient graphical user interface for model discrimination. We demonstrate the beneficial operation of the discrimination approach and the usefulness of the software tool by analyzing a realistic benchmark experiment from literature. New robust optimal designs that allow to discriminate between the investigated model hypotheses of the benchmark experiment are successfully calculated and yield promising results. The involved robustification approach provides maximally discriminating experiments for the worst parameter configurations, which can be used to estimate the meaningfulness of upcoming experiments. A major benefit of the graphical user interface is the ability to interactively investigate the model behavior and the clear arrangement of numerous variables. In addition to a brief theoretical overview of the discrimination method and the functionality of the software tool, the importance of robustness of experimental designs against parameter variability is demonstrated on a biochemical benchmark problem. The software is licensed under the GNU General Public License

  7. Nonstandard interaction effects on neutrino parameters at medium-baseline reactor antineutrino experiments

    NASA Astrophysics Data System (ADS)

    Ohlsson, Tommy; Zhang, He; Zhou, Shun

    2014-01-01

    Precision measurements of leptonic mixing parameters and the determination of the neutrino mass hierarchy are the primary goals of the forthcoming medium-baseline reactor antineutrino experiments, such as JUNO and RENO-50. In this work, we investigate the impact of nonstandard neutrino interactions (NSIs) on the measurements of {sin2 θ12,Δm212} and {sin2 θ13,Δm312}, and on the sensitivity to the neutrino mass hierarchy, at the medium-baseline reactor experiments by assuming a typical experimental setup. It turns out that the true mixing parameter sin2 θ12 can be excluded at a more than 3σ level if the NSI parameter ɛ or ɛ is as large as 2% in the most optimistic case. However, the discovery reach of NSI effects has been found to be small, and depends crucially on the CP-violating phases. Finally, we show that NSI effects could enhance or reduce the discrimination power of the JUNO and RENO-50 experiments between the normal and inverted neutrino mass hierarchies.

  8. Enactive cinema paves way for understanding complex real-time social interaction in neuroimaging experiments

    PubMed Central

    Tikka, Pia; Väljamäe, Aleksander; de Borst, Aline W.; Pugliese, Roberto; Ravaja, Niklas; Kaipainen, Mauri; Takala, Tapio

    2012-01-01

    We outline general theoretical and practical implications of what we promote as enactive cinema for the neuroscientific study of online socio-emotional interaction. In a real-time functional magnetic resonance imaging (rt-fMRI) setting, participants are immersed in cinematic experiences that simulate social situations. While viewing, their physiological reactions—including brain responses—are tracked, representing implicit and unconscious experiences of the on-going social situations. These reactions, in turn, are analyzed in real-time and fed back to modify the cinematic sequences they are viewing while being scanned. Due to the engaging cinematic content, the proposed setting focuses on living-by in terms of shared psycho-physiological epiphenomena of experience rather than active coping in terms of goal-oriented motor actions. It constitutes a means to parametrically modify stimuli that depict social situations and their broader environmental contexts. As an alternative to studying the variation of brain responses as a function of a priori fixed stimuli, this method can be applied to survey the range of stimuli that evoke similar responses across participants at particular brain regions of interest. PMID:23125829

  9. Computational analysis of the tether pulling experiment to probe plasma membrane - cytoskeleton interaction in cells

    PubMed Central

    Schumacher, Kristopher R.; Popel, Aleksander S.; Anvari, Bahman; Brownell, William E.; Spector, Alexander A.

    2016-01-01

    Tethers are thin membrane tubes that can be formed when relatively small and localized forces are applied to cellular membranes and lipid bilayers. Tether pulling experiments have been used to better understand the fine membrane properties. These include the interaction between the plasma membrane and the underlying cytoskeleton, which is an important factor affecting membrane mechanics. We use a computational method aimed at the interpretation and design of tether pulling experiments in cells with a strong membrane-cytoskeleton attachment. In our model, we take into account the detailed information on the topology of bonds connecting the plasma membrane and the cytoskeleton. We compute the force-dependent piecewise membrane deflection and bending as well as modes of stored energy in three major regions of the system: body of the tether, membrane-cytoskeleton attachment zone, and the transition zone between the two. We apply our method to three cells: cochlear outer hair cells (OHCs), human embryonic kidney (HEK) cells, and Chinese hamster ovary (CHO) cells. OHCs have a special system of pillars connecting the membrane and the cytoskeleton, and HEK and CHO cells have a bond arrangement via bonds (e.g., PIP2) which is common to many other cells. We also present a validation of our model by using experimental data on CHO and HEK cells. The proposed method can be an effective tool in the analyses of experiments to probe the properties of cellular membranes. PMID:19905340

  10. Laboratory experiments to study supersonic astrophysical flows interacting with clumpy environments

    NASA Astrophysics Data System (ADS)

    Rosen, P. A.; Foster, J. M.; Wilde, B. H.; Coker, R.; Blue, B. E.; Williams, R. J. R.; Hansen, F.; Sorce, C.; Hartigan, P.; Carver, R.; Palmer, J.

    2008-11-01

    A wide variety of objects in the universe drive supersonic outflows through the interstellar medium which is often highly clumpy. These inhomogeneities affect the morphology of the shocks that are generated. The hydrodynamics is difficult to model as the problem is inherently 3D and the clumps are subject to a variety of fluid instabilities as they are accelerated and destroyed by the shock. We have been carrying out experiments on the University of Rochester's Omega laser to address the interaction of a shock wave with a single spherical particle. We use a 1.6-mm diameter, 1.2-mm length hohlraum to drive a composite plastic ablator (which includes bromine to prevent M-band radiation from preheating the experiment). The ablator acts as a ``piston'' driving a shock into 0.3 g/cc foam containing a 0.5-mm diameter sapphire or 1.0-mm diameter plastic sphere. We radiograph along two orthogonal lines of sight, using pinhole-apertured x-ray backlighters, to study the subsequent hydrodynamics. We present initial experimental results and multi-dimensional simulations of the experiment.

  11. MHD modeling of atlas experiments to study transverse shear interface interactions

    SciTech Connect

    Cochran, F. L.; Hammerberg, J. E.; Keinigs, R. K.; Faehl, R. J.

    2001-01-01

    The transverse shear established at the interface of two solids moving at differential velocities on the order of the sound speed is being studied in experiments on the ATLAS capacitor bank at Los Alamos. The ATLAS bank has finished certification tests and has demonstrated peak currents of 27.5 MA into an inductive load with a risetime of 5 microseconds. One- and two-dimensional MHD calculations have been performed in support of these 'friction-like' ATLAS experiments. Current flowing along the outer surface of a thick aluminum liner, 10 mm thick at impact with the interaction target, accelerates the liner to velocities of {approx}1.0-1.5 km/s. This cylindrically imploding liner impacts a target assembly composed of alternating disks of high- and low-density materials. Different shock speeds in the two materials leads to a differential velocity along the interface. Shock heating, elastic-plastic flow, and stress transport are included in the calculations. Material strength properties are modeled with a Steinburg-Guinan treatment in these first studies. Various design configurations for the ATLAS experiments are now being considered and will be presented.

  12. Acoustic interactions between an altitude test facility and jet engine plumes: Theory and experiments

    NASA Technical Reports Server (NTRS)

    Ahuja, K. K.; Jones, R. R., III; Tam, C. K.; Massey, K. C.; Fleming, A. J.

    1992-01-01

    The overall objective of the described effort was to develop an understanding of the physical mechanisms involved in the flow/acoustic interactions experienced in full-scale altitude engine test facilities. This is done by conducting subscale experiments and through development of a theoretical model. Model cold jet experiments with an axisymmetric convergent nozzle are performed in a test setup that stimulates a supersonic jet exhausting into a cylindrical diffuser. The measured data consist of detailed flow visualization data and acoustic spectra for a free and a ducted plume. It is shown that duct resonance is most likely responsible by theoretical calculations. Theoretical calculations also indicate that the higher discrete tones observed in the measurements are related to the screech phenomena. Limited experiments on the sensitivity of a free 2-D, C-D nozzle to externally imposed sound are also presented. It is shown that a 2-D, C-D nozzle with a cutback is less excitable than a 2-D C-D nozzle with no cutback. At a pressure ratio of 1.5 unsteady separation from the diverging walls of the nozzle is noticed. This separation switches from one wall to the opposite wall thus providing an unsteady deflection of the plume. It is shown that this phenomenon is related to the venting provided by the cutback section.

  13. Spatial variability in river-catchment interaction: Combining radon measurements and salt tracer experiments

    NASA Astrophysics Data System (ADS)

    Angermann, Lisa; Tecklenburg, Christina; Blume, Theresa

    2013-04-01

    Hydrological modeling is commonly based on a discharge calibration. This approach, however, is often insufficient to properly reproduce conditions that exceed the range of calibrated conditions and is therefore inadequate for predicting reactions to a changing environment. Small headwater catchments are often characterized by manifold morphological attributes (e.g. changes in river course, variable depth to bedrock...) and complex topography, resulting in potentially high spatial variability of river-catchment interactions. Such systems are often poorly represented by simple rainfall runoff models. For that reason, increasing effort is taken to investigate the functional organization of river catchments. From a river's point of view, the first questions to be solved are: How variable is river-catchment interaction in space? Where along the river do we find exfiltrating or infiltrating conditions? Which pathway did the water take before entering the stream? To investigate these questions we used an approach that combined salt tracer experiments with Radon-222 (referred to as radon) measurements. Radon is a natural occurring radionuclide that is accumulated in water traveling through saturated bedrock and mineral material. In contact with air the inert noble gas degases quickly and is thus a reliable environmental tracer for groundwater-surface water interactions. Measurements were carried out at a 650 m long tributary of the Colpach, which is part of the Attert basin in Luxembourg. In the first phase of the experiment radon was sampled every 50 m along the tributary. At the same time, salt tracer experiments were conducted over 100 m sections, providing information on discharge at the up- and downstream end of each 100 m section, absolute gain and loss along the 100 m section and travel times between all radon sampling sites. In the second phase, three sections where investigated in more detail. The chosen sections were divided according to changes of morphological

  14. Nitrous oxide and methane in Atlantic and Mediterranean waters in the Strait of Gibraltar: Air-sea fluxes and inter-basin exchange

    NASA Astrophysics Data System (ADS)

    de la Paz, M.; Huertas, I. E.; Flecha, S.; Ríos, A. F.; Pérez, F. F.

    2015-11-01

    The global ocean plays an important role in the overall budget of nitrous oxide (N2O) and methane (CH4), as both gases are produced within the ocean and released to the atmosphere. However, for large parts of the open and coastal oceans there is little or no spatial data coverage for N2O and CH4. Hence, a better assessment of marine emissions estimates is necessary. As a contribution to remedying the scarcity of data on marine regions, N2O and CH4 concentrations have been determined in the Strait of Gibraltar at the ocean Fixed Time series (GIFT). During six cruises performed between July 2011 and November 2014 samples were collected at the surface and various depths in the water column, and subsequently measured using gas chromatography. From this we were able to quantify the temporal variability of the gas air-sea exchange in the area and examine the vertical distribution of N2O and CH4 in Atlantic and Mediterranean waters. Results show that surface Atlantic waters are nearly in equilibrium with the atmosphere whereas deeper Mediterranean waters are oversaturated in N2O, and a gradient that gradually increases with depth was detected in the water column. Temperature was found to be the main factor responsible for the seasonal variability of N2O in the surface layer. Furthermore, although CH4 levels did not reveal any feature clearly associated with the circulation of water masses, vertical distributions showed that higher concentrations are generally observed in the Atlantic layer, and that the deeper Mediterranean waters are considerably undersaturated (by up to 50%). Even though surface waters act as a source of atmospheric N2O during certain periods, on an annual basis the net N2O flux in the Strait of Gibraltar is only 0.35 ± 0.27 μmol m-2 d-1, meaning that these waters are almost in a neutral status with respect to the atmosphere. Seasonally, the region behaves as a slight sink for atmospheric CH4 in winter and as a source in spring and fall. Approximating

  15. Fixed point Open Ocean Observatory network (FixO3): Multidisciplinary observations from the air-sea interface to the deep seafloor

    NASA Astrophysics Data System (ADS)

    Lampitt, Richard; Cristini, Luisa

    2014-05-01

    The Fixed point Open Ocean Observatory network (FixO3) seeks to integrate the 23 European open ocean fixed point observatories and to improve access to these key installations for the broader community. These will provide multidisciplinary observations in all parts of the oceans from the air-sea interface to the deep seafloor. Coordinated by the National Oceanography Centre, UK, FixO3 builds on the significant advances achieved through the previous Europe-funded FP7 programmes EuroSITES, ESONET and CARBOOCEAN. Started in September 2013 with a budget of 7 Million Euros over 4 years the project has 29 partners drawn from academia, research institutions and SME's. In addition 12 international experts from a wide range of disciplines comprise an Advisory Board. On behalf of the FixO3 Consortium, we present the programme that will be achieved through the activities of 12 Work Packages: 1. Coordination activities to integrate and harmonise the current procedures and processes. Strong links will be fostered with the wider community across academia, industry, policy and the general public through outreach, knowledge exchange and training. 2. Support actions to offer a) free access to observatory infrastructures to those who do not have such access, and b) free and open data services and products. 3. Joint research activities to innovate and enhance the current capability for multidisciplinary in situ ocean observation. Support actions include Transnational Access (TNA) to FixO3 infrastructure, meaning that European organizations can apply to free-of-charge access to the observatories for research and testing in two international calls during the project lifetime. The first call for TNA opens in summer 2014. More information can be found on FixO3 website (www.fixo3.eu/). Open ocean observation is currently a high priority for European marine and maritime activities. FixO3 will provide important data on environmental products and services to address the Marine Strategy

  16. Non-linear wave interaction in a magnetoplasma column. I - Theory. II Experiment

    NASA Technical Reports Server (NTRS)

    Larsen, J.-M.; Crawford, F. W.

    1979-01-01

    The paper presents an analysis of non-linear three-wave interaction for propagation along a cylindrical plasma column surrounded either by a metallic boundary, or by an infinite dielectric, and immersed in an infinite, static, axial magnetic field. An averaged Lagrangian method is used and the results are specialized to parametric amplification and mode conversion, assuming an undepleted pump wave. Computations are presented for a magneto-plasma column surrounded by free space, indicating that parametric growth rates of the order of a fraction of a decibel per centimeter should be obtainable for plausible laboratory plasma parameters. In addition, experiments on non-linear mode conversion in a cylindrical magnetoplasma column are described. The results are compared with the theoretical predictions and good qualitative agreement is demonstrated.

  17. The interactive effect of social pain and executive functioning on aggression: an fMRI experiment

    PubMed Central

    Eisenberger, Naomi I.; Pond, Richard S.; Richman, Stephanie B.; Bushman, Brad J.; DeWall, C. Nathan

    2014-01-01

    Social rejection often increases aggression, but the neural mechanisms underlying this effect remain unclear. This experiment tested whether neural activity in the dorsal anterior cingulate cortex (dACC) and anterior insula in response to social rejection predicted greater subsequent aggression. Additionally, it tested whether executive functioning moderated this relationship. Participants completed a behavioral measure of executive functioning, experienced social rejection while undergoing functional magnetic resonance imaging and then completed a task in which they could aggress against a person who rejected them using noise blasts . We found that dACC activation and executive functioning interacted to predict aggression. Specifically, participants with low executive functioning showed a positive association between dACC activation and aggression, whereas individuals with high executive functioning showed a negative association. Similar results were found for the left anterior insula. These findings suggest that social pain can increase or decrease aggression, depending on an individual’s regulatory capability. PMID:23482622

  18. Interaction between Japanese flowering cherry trees and some wild animals observed during physiological experiment in fields

    NASA Technical Reports Server (NTRS)

    Nakamura, Teruko

    2003-01-01

    We have studied the weeping habit of Japanese flowering cherry tree in the field of Tama Forest Science Garden, Forestry and Forest Products Research Institute at the foot of Mt. Takao. Since cherry trees at various age were the materials for our plant physiology experiments, our studies were conducted in the fields where we experienced certain difficulties. Even under such difficult environment that was rather unexpected and uncontrollable, we could obtain fruitful results on the growth of cherry tree, and found them scientifically significant, especially in terms of biological effects of gravity on earth. Moreover, a lot of interesting interactions of cherry trees with various kinds of animals were observed in parallel to the plant physiology.

  19. Magnetic measurements in model experiments. [solar wind interaction with geomagnetic field

    NASA Technical Reports Server (NTRS)

    Dubinin, E. M.; Managadze, G. G.; Podgornyy, I. M.

    1974-01-01

    Plasma parameters for modeling of the interaction between the solar wind and the earth's magnetic field are selected on the limited modeling principle (plasma velocity 3 x 10 to the 7th power cm/sec, density 10 to the 13th power cm/3, electron temperature approximately 15 eV). Measurements were made with magnetic probes capable of developing all 3 components inside the magnetic field. The resulting magnetic field charts indicate that a neutral layer forms on the night side in the model experiments. A magnetosphere free of plasma streams is established on the daytime side. A shock wave forms on the boundary of the magnetosphere, its width c/omega sub 0 in accordance with theory, where omega sub 0 is the total Langmuir width.

  20. Operational characteristics and preliminary results of a plasma-propellant interaction experiment

    NASA Astrophysics Data System (ADS)

    Edwards, Charles M.; Bourham, Mohamed A.; Gilligan, John G.

    1993-11-01

    The interaction of plasmas with propellants (solids and liquids) may lead to augmented chemical burn rates in electrothermal-chemical (ETC) guns. The plasma generator for many plasma-propellant reaction concepts is an electrothermal source. The 'pipe' experiment is a device that injects a low-temperature (1-3 eV), high density (10(exp 25) - 10(exp 26))/cu m plasma to the surface of either a solid or a liquid propellant. The ET source injects the plasma into the propellant that is placed on a test stand, followed by a material test stand to expose material surfaces to the plasma under combustion conditions. Various diagnostics are arranged to measure the plasma parameters, absolute pressure, stress distribution, high heat flux calorimetry, velocity, and burn rates.

  1. Preliminary results from the flight of the Solar Array Module Plasma Interactions Experiment (SAMPIE)

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Hillard, G. Barry

    1994-01-01

    SAMPIE, the Solar Array Module Plasma Interactions Experiment, flew in the Space Shuttle Columbia payload bay as part of the Office of Aeronautics and Space Technology-2 (OAST-2) mission on STS-62, March, 1994. SAMPIE biased samples of solar arrays and space power materials to varying potentials with respect to the surrounding space plasma, and recorded the plasma currents collected and the arcs which occurred, along with a set of plasma diagnostics data. A large set of high quality data was obtained on the behavior of solar arrays and space power materials in the space environment. This paper is the first report on the data SAMPIE telemetered to the ground during the mission. It will be seen that the flight data promise to help determine arcing thresholds, snapover potentials, and floating potentials for arrays and spacecraft in LEO.

  2. Photon emission in neutral current interactions at the T2K experiment

    NASA Astrophysics Data System (ADS)

    Wang, E.; Alvarez-Ruso, L.; Hayato, Y.; Mahn, K.; Nieves, J.

    2015-09-01

    We have applied a microscopic model for single photon emission in neutral current interactions on nucleons and nuclei to determine the number and distributions of such events at the Super-Kamiokande detector, for the flux and beam exposure of the T2K experiment in neutrino mode. These reactions represent an effectively irreducible background in electron-(anti)neutrino appearance measurements aimed at a precise measurement of mixing angle θ13 and the C P violating phase. We have obtained a total number of photon events that is twice as large as the one from the NEUT event generator (version 5.1.4.2) used in the analysis of T2K data. Detailed comparisons of energy and angular distributions for the νμ and ν¯μ fluxes have also been performed.

  3. Interactive data analysis for astronomy Shuttle experiments at Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Klinglesmith, D. A., III

    1981-01-01

    The eye as an efficient selection device for determining what is important in astronomical imagery can be greatly aided by the computer. A suitable facility, called the Interactive Astronomical Data Analysis Facility (IADAF), has been developed for the display and analysis of astronomical imagery by the Laboratory for Astronomy and Solar Physics. The Laboratory for Astronomy and Solar Physics currently has approval to fly two experiments on Spacelab. The Solar Extreme Ultraviolet Telescope (SEUTS) is to be used for the study of several fundamental problems of solar physics. The Ultraviolet Image Telescope for Astronomical Investigations (UIT) is to provide direct imagery of selected fields of view throughout the sky. A description is given of IADAF, taking into account its 16-bit computer and the COMTAL image processing display system. The use of IADAF by SEUTS and UIT is discussed.

  4. The interactive effect of social pain and executive functioning on aggression: an fMRI experiment.

    PubMed

    Chester, David S; Eisenberger, Naomi I; Pond, Richard S; Richman, Stephanie B; Bushman, Brad J; Dewall, C Nathan

    2014-05-01

    Social rejection often increases aggression, but the neural mechanisms underlying this effect remain unclear. This experiment tested whether neural activity in the dorsal anterior cingulate cortex (dACC) and anterior insula in response to social rejection predicted greater subsequent aggression. Additionally, it tested whether executive functioning moderated this relationship. Participants completed a behavioral measure of executive functioning, experienced social rejection while undergoing functional magnetic resonance imaging and then completed a task in which they could aggress against a person who rejected them using noise blasts . We found that dACC activation and executive functioning interacted to predict aggression. Specifically, participants with low executive functioning showed a positive association between dACC activation and aggression, whereas individuals with high executive functioning showed a negative association. Similar results were found for the left anterior insula. These findings suggest that social pain can increase or decrease aggression, depending on an individual's regulatory capability. PMID:23482622

  5. Pushing the limits of plasma length in inertial-fusion laser-plasma interaction experiments.

    PubMed

    Froula, D H; Divol, L; London, R A; Michel, P; Berger, R L; Meezan, N B; Neumayer, P; Ross, J S; Wallace, R; Glenzer, S H

    2008-01-11

    We demonstrate laser beam propagation and low backscatter in laser produced hohlraum plasmas of ignition plasma length. At intensities I < 5 x 10(14) W cm(-2) greater than 80% of the energy in a blue (3 omega, 351 nm) laser is transmitted through a L=5-mm long, high-temperature (Te = 2.5 keV), high-density (ne = 5 x 10(20) cm(-3)) plasma. These experiments show that the backscatter scales exponentially with plasma length which is consistent with linear theory. The backscatter calculated by a new steady state 3D laser-plasma interaction code developed for large ignition plasmas is in good agreement with the measurements. PMID:18232778

  6. Pushing the limits of plasma length in inertial fusion laser-plasma interaction experiments

    SciTech Connect

    Froula, D; Divol, L; London, R; Michel, P; Berger, R L; Meezan, N; Neumayer, P; Ross, J; Wallace, R; Glenzer, S H

    2007-08-02

    We demonstrate laser beam propagation and low backscatter in laser produced hohlraum plasmas of ignition plasma length. At intensities I < 5 x 10{sup 14} W cm{sup -2} greater than 80% of the energy in a blue (3{omega}, 351 nm) laser is transmitted through a L=5-mm long, high-temperature (T{sub e} = 2.5 keV), high-density (n{sub e} = 5 x 10{sup 20} cm{sup -3}) plasma. These experiments show that the backscatter scales exponentially with plasma length which is consistent with linear theory. The backscatter calculated by a new steady state 3D laser-plasma interaction code developed for large ignition plasmas is in good agreement with the measurements.

  7. Preliminary results from the flight of the Solar Array Module Plasma Interactions Experiment (SAMPIE)

    SciTech Connect

    Ferguson, D.C.; Hillard, G.B.

    1994-09-01

    SAMPIE, the Solar Array Module Plasma Interactions Experiment, flew in the Space Shuttle Columbia payload bay as part of the Office of Aeronautics and Space Technology-2 (OAST-2) mission on STS-62, March, 1994. SAMPIE biased samples of solar arrays and space power materials to varying potentials with respect to the surrounding space plasma, and recorded the plasma currents collected and the arcs which occurred, along with a set of plasma diagnostics data. A large set of high quality data was obtained on the behavior of solar arrays and space power materials in the space environment. This paper is the first report on the data SAMPIE telemetered to the ground during the mission. It will be seen that the flight data promise to help determine arcing thresholds, snapover potentials, and floating potentials for arrays and spacecraft in LEO.S

  8. Study on water-rock interactions of trace elements in groundwater with leaching experiments.

    PubMed

    Yu, Z; Zhang, L; Jiang, P; Papelis, C; Li, Y

    2015-04-01

    Measurements of trace elements leached from host rocks can indicate the source of flowing groundwater and provide the host rock's fingerprint information that may be useful in understanding the mixing patterns of different groundwaters and flowpaths. In this study, the leaching characteristics of three widely-distributed aquifer host rocks in Southern Nevada were investigated through leaching experiments of 13 trace elements under different experimental conditions (leaching time, pH, grain size, and rock mineralogy). The fraction of leached trace elements from different aquifer host rocks was calculated for examining the water-rock interaction in different conditions. The effect of host rock mineralogy on leachate composition was examined, which could provide useful information about groundwater source. Solute speciation and saturation indices were simulated using geochemical modeling to further explore the redistribution and leaching process of trace elements. PMID:24601971

  9. New precision era of experiments on strong interaction with strangeness at DAFNE/LNF-INFN

    NASA Astrophysics Data System (ADS)

    Ishiwatari, T.; Bazzi, M.; Beer, G.; Berucci, C.; Bombelli, L.; Bragadireanu, A. M.; Cargnelli, M.; Curceanu, C.; d'Uffizi, A.; Fiorini, C.; Ghio, F.; Guaraldo, C.; Hayano, R. S.; Iliescu, M.; Iwasaki, M.; Kienle, P.; Levi Sandri, P.; Longoni, A.; Marton, J.; Okada, S.; Pietreanu, D.; Ponta, T.; Quaglia, R.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, D. L.; Sirghi, F.; Tatsuno, H.; Tudorache, A.; Tudorache, V.; Vazquez Doce, O.; Wünschek, B.; Widmann, E.; Zmeskal, J.

    2014-03-01

    The strong-interaction shifts and widths of kaonic hydrogen, deuterium, 3He, and 4He were measured in the SIDDHARTA experiment. The most precise values of the shift and width of the kaonic hydrogen 1s state were determined to be ɛ1s = -283 ± 36(stat)±6(syst) eV and Γ1s = 541±89(stat)±22(syst) eV. The upper limit of the kaonic deuterium Kα yield was found to be ≤ 0.39%. In addition, the shifts and widths of the kaonic 3He and 4He 2p states were determined to be ɛ2p(3He) = -2 ± 2(stat) ± 4(syst) eV and Γ2p(3He) = 6 ± 6(stat) ± 7(syst) eV; ɛ2p(4He) = +5 ± 3(stat) ± 4(syst) eV and Γ2p(4He) = 14 ± 8(stat) ± 5(syst) eV. These values are important for the constraints of the low-energy bar KN interaction in theoretical approaches.

  10. High resolution renderings and interactive visualization of the 2006 Huntington Beach experiment

    NASA Astrophysics Data System (ADS)

    Im, T.; Nayak, A.; Keen, C.; Samilo, D.; Matthews, J.

    2006-12-01

    The Visualization Center at the Scripps Institution of Oceanography investigates innovative ways to represent graphically interactive 3D virtual landscapes and to produce high resolution, high quality renderings of Earth sciences data and the sensors and instruments used to collect the data . Among the Visualization Center's most recent work is the visualization of the Huntington Beach experiment, a study launched in July 2006 by the Southern California Ocean Observing System (http://www.sccoos.org/) to record and synthesize data of the Huntington Beach coastal region. Researchers and students at the Visualization Center created visual presentations that combine bathymetric data provided by SCCOOS with USGS aerial photography and with 3D polygonal models of sensors created in Maya into an interactive 3D scene using the Fledermaus suite of visualization tools (http://www.ivs3d.com). In addition, the Visualization Center has produced high definition (HD) animations of SCCOOS sensor instruments (e.g. REMUS, drifters, spray glider, nearshore mooring, OCSD/USGS mooring and CDIP mooring) using the Maya modeling and animation software and rendered over multiple nodes of the OptIPuter Visualization Cluster at Scripps. These visualizations are aimed at providing researchers with a broader context of sensor locations relative to geologic characteristics, to promote their use as an educational resource for informal education settings and increasing public awareness, and also as an aid for researchers' proposals and presentations. These visualizations are available for download on the Visualization Center website at http://siovizcenter.ucsd.edu/sccoos/hb2006.php.

  11. Gene–Environment Interaction in Major Depression: Focus on Experience-Dependent Biological Systems

    PubMed Central

    Lopizzo, Nicola; Bocchio Chiavetto, Luisella; Cattane, Nadia; Plazzotta, Giona; Tarazi, Frank I.; Pariante, Carmine M.; Riva, Marco A.; Cattaneo, Annamaria

    2015-01-01

    Major depressive disorder (MDD) is a multifactorial and polygenic disorder, where multiple and partially overlapping sets of susceptibility genes interact each other and with the environment, predisposing individuals to the development of the illness. Thus, MDD results from a complex interplay of vulnerability genes and environmental factors that act cumulatively throughout individual’s lifetime. Among these environmental factors, stressful life experiences, especially those occurring early in life, have been suggested to exert a crucial impact on brain development, leading to permanent functional changes that may contribute to lifelong risk for mental health outcomes. In this review, we will discuss how genetic variants (polymorphisms, SNPs) within genes operating in neurobiological systems that mediate stress response and synaptic plasticity, can impact, by themselves, the vulnerability risk for MDD; we will also consider how this MDD risk can be further modulated when gene × environment interaction is taken into account. Finally, we will discuss the role of epigenetic mechanisms, and in particular of DNA methylation and miRNAs expression changes, in mediating the effect of the stress on the vulnerability risk to develop MDD. Taken together, we aim to underlie the role of genetic and epigenetic processes involved in stress- and neuroplasticity-related biological systems on the development of MDD after exposure to early life stress, thereby building the basis for future research and clinical interventions. PMID:26005424

  12. Elemental mercury (Hg(0)) in air and surface waters of the Yellow Sea during late spring and late fall 2012: concentration, spatial-temporal distribution and air/sea flux.

    PubMed

    Ci, Zhijia; Wang, Chunjie; Wang, Zhangwei; Zhang, Xiaoshan

    2015-01-01

    The Yellow Sea in East Asia receives great Hg input from regional emissions. However, Hg cycling in this marine system is poorly investigated. In late spring and late fall 2012, we determined gaseous elemental Hg (GEM or Hg(0)) in air and dissolved gaseous Hg (DGM, mainly Hg(0)) in surface waters to explore the spatial-temporal variations of Hg(0) and further to estimate the air/sea Hg(0) flux in the Yellow Sea. The results showed that the GEM concentrations in the two cruises were similar (spring: 1.86±0.40 ng m(-3); fall: 1.84±0.50 ng m(-3)) and presented similar spatial variation pattern with elevated concentrations along the coast of China and lower concentrations in the open ocean. The DGM concentrations of the two cruises were also similar with 27.0±6.8 pg L(-1) in the spring cruise and 28.2±9.0 pg L(-1) in the fall cruise and showed substantial spatial variation. The air/sea Hg(0) fluxes in the spring cruise and fall cruise were estimated to be 1.06±0.86 ng m(-2) h(-1) and 2.53±2.12 ng m(-2) h(-1), respectively. The combination of this study and our previous summer cruise showed that the summer cruise presented enhanced values of GEM, DGM and air/sea Hg(0) flux. The possible reason for this trend was that high solar radiation in summer promoted Hg(0) formation in seawater, and the high wind speed during the summer cruise significantly increased Hg(0) emission from sea surface to atmosphere and subsequently enhanced the GEM levels. PMID:24999267

  13. Large eddy simulations and experiments of nonlinear flow interactions in hybrid rocket combustion

    NASA Astrophysics Data System (ADS)

    Na, Y.; Lee, C.

    2013-03-01

    Nonlinear combustion phenomenon was investigated through an experiment in a hybrid rocket motor. A poly(methyl methacrylate) (PMMA) / gaseous oxygen (GOx) combination was used with several types of disks equipped in a prechamber with the aim of modifying the local turbulent flow. By allowing this disturbance generated in a prechamber to interact with the shedding vortex inherently produced in the main chamber, a possibility of commonly observed nonlinear combustion feature such as DC-shift was analyzed. In a baseline test, a vortex shedding occurs due to the interaction of a main oxidizer flow with the evaporated fuel stream coming out of the surface during the regression process. Among the several types of disks, it turned out that only the disk4 produced the excitation which subsequently suppressed the vortex shedding phenomenon in the main chamber. This descent interaction was reflected in a sudden pressure drop (which may be described as direct current (DC) shift) of about 10 psi in the time history of the pressure during the nominal combustion. The present result with the disk4 suggests the possibility of phase cancellation between the excitation induced by the disk4 and the shedding vortex but much more work should be conducted to extract more accurate correlation of the phase information. In order to understand the baseline flow physics, a compressible large eddy simulation (LES) was conducted with the prescribed wall blowing boundary condition. The result clearly exhibited the existence of vortex shedding phenomenon with a specified frequency. The fact that important flow features of the present computation are quite similar to those obtained with an incompressible assumption in a flat channel suggests that both compressibility and curvature effects do not dominate in the present flow configuration.

  14. Study of turbulence and interacting inertial modes in a differentially rotating spherical shell experiment

    NASA Astrophysics Data System (ADS)

    Hoff, Michael; Harlander, Uwe; Triana, Santiago Andrés

    2016-08-01

    We present a study of inertial modes in a differentially rotating spherical shell (spherical Couette flow) experiment with a radius ratio of η =1 /3 . Inertial modes are Coriolis-restored linear wave modes which often arise in rapidly rotating fluids. Recent experimental work has shown that inertial modes exist in a spherical Couette flow for Ωi<Ωo , where Ωi and Ωo are the inner and outer sphere rotation rate. A finite number of particular inertial modes has previously been found. By scanning the Rossby number from -2.5 experiments. We show that the kinetic energy of the dominant inertial mode dramatically increases with decreasing Rossby number, which eventually leads to a wave breaking and an increase of small-scale structures at a critical Rossby number. Such a transition in a spherical Couette flow has not been described before. The critical Rossby number scales with the Ekman number as E1 /5. Additionally, the increase of small-scale features beyond the transition transfers energy to a massively enhanced mean flow around the tangent cylinder. In this context, we discuss an interaction between the dominant inertial modes with a geostrophic Rossby mode exciting secondary modes whose frequencies match the triadic resonance condition.

  15. Design of an Experiment to Observe Laser-Plasma Interactions on NIKE

    NASA Astrophysics Data System (ADS)

    Phillips, L.; Weaver, J.; Manheimer, W.; Zalesak, S.; Schmitt, A.; Fyfe, D.; Afeyan, B.; Charbonneau-Lefort, M.

    2007-11-01

    Recent proposed designs (Obenschain et al., Phys. Plasmas 13 056320 (2006)) for direct-drive ICF targets for energy applications involve high implosion velocities combined with higher laser irradiances. The use of high irradiances increases the likelihood of deleterious laser plasma instabilities (LPI) that may lead, for example, to the generation of fast electrons. The proposed use of a 248 nm KrF laser to drive these targets is expected to minimize LPI; this is being studied by experiments at NRL's NIKE facility. We used a modification of the FAST code that models laser pulses with arbitrary spatial and temporal profiles to assist in designing these experiments. The goal is to design targets and pulseshapes to create plasma conditions that will produce sufficient growth of LPI to be observable on NIKE. Using, for example, a cryogenic DT target that is heated by a brief pulse and allowed to expand freely before interacting with a second, high-intensity pulse, allows the development of long scalelengths at low electron temperatures and leads to a predicted 20-efold growth in two-plasmon amplitude.

  16. Spectroscopic Analysis of High Intensity Laser Beam Jets Interaction Experiments on the Leopard Laser at UNR

    NASA Astrophysics Data System (ADS)

    Petkov, E. E.; Weller, M. E.; Kantsyrev, V. L.; Safronova, A. S.; Moschella, J. J.; Shrestha, I.; Shlyapsteva, V. V.; Stafford, A.; Keim, S. F.; University of Nevada Reno Team

    2013-10-01

    Results of Ar gas-puff experiments performed on the high power Leopard laser at UNR are presented. Flux density of laser radiation in focal spot was up to 2 × 1016 W/cm2 (pulse duration was 0.8 ns and laser wavelength was 1.057 μm). Specifically, spectroscopic analysis of K-shell Ar spectra are investigated and compared as functions of the orientation of the laser beam to linear gas jet. The laser beam axis was positioned either along the jet plane or orthogonal to it at a distance of 1 mm from the nozzle output. The diagnostics used included a time-integrated x-ray spectrometer along with a set of filtered Si diodes with various cutoff energies. In order to identify lines, a non-local thermodynamic equilibrium (non-LTE) kinetic model was utilized and was also used to determine plasma parameters such as electron temperature and density. The importance of the spectroscopic study of high intensity laser beam-jets interaction experiments is discussed. This work was supported by the Defense Threat Reduction Agency, Basic Research Award # HDTRA1-13-1-0033, to University of Nevada, Reno, and in part by the DOE/NNSA Cooperative agreements DE-NA0001984 and DE-FC52-06NA27616.

  17. Tritium plasma experiment: Parameters and potentials for fusion plasma-wall interaction studies

    SciTech Connect

    Shimada, Masashi; Sharpe, J. Phillip; Kolasinski, Robert D.; Causey, Rion A.

    2011-08-15

    The tritium plasma experiment (TPE) is a unique facility devoted to experiments on the behavior of deuterium/tritium in toxic (e.g., beryllium) and radioactive materials for fusion plasma-wall interaction studies. A Langmuir probe was added to the system to characterize the plasma conditions in TPE. With this new diagnostic, we found the achievable electron temperature ranged from 5.0 to 10.0 eV, the electron density varied from 5.0 x 10{sup 16} to 2.5 x 10{sup 18} m{sup -3}, and the ion flux density varied between 5.0 x 10{sup 20} to 2.5 x 10{sup 22} m{sup -2} s{sup -1} along the centerline of the plasma. A comparison of these plasma parameters with the conditions expected for the plasma facing components (PFCs) in ITER shows that TPE is capable of achieving most ({approx}800 m{sup 2} of 850 m{sup 2} total PFCs area) of the expected ion flux density and electron density conditions.

  18. Tritium Plasma Experiment (TPE) - parameters and potentials for fusion plasma-wall interaction studies

    SciTech Connect

    Masashi Shimada; Robert D. Kolasinski; J. Phillip Sharpe; Rion A. Causey

    2011-08-01

    The Tritium plasma experiment (TPE) is a unique facility devoted to experiments on the behavior of deuterium/tritium in toxic (e.g. beryllium) and radioactive materials for fusion plasma-wall interaction (PWI) studies. A Langmuir probe was added to the system to characterize the plasma conditions in TPE. With this new diagnostic, we found the achievable electron temperature ranged from 5.0 to 10.0 eV, the electron density varied from 5.0 x 10{sup 16} to 2.5 x 10{sup 18} m{sup -3}, and the ion flux density varied between 5.0 x 10{sup 20} to 2.5 x 10{sup 22} m{sup -2}s{sup -1} along the centerline of the plasma. A comparison of these plasma parameters with the conditions expected for the plasma facing components (PFCs) in ITER shows that TPE is capable of achieving most (approximately 800 m{sup 2} of 850 m{sup 2} total PFCs area) of the expected ion flux density and electron density conditions.

  19. Criticality: the experience of developing an interactive educational tool based on board games.

    PubMed

    Gibson, Vanessa; Douglas, Margaret

    2013-12-01

    Critical care services have seen many changes over recent years prompted by the seminal paper by the Department of Health (2000) Comprehensive critical care: A review of adult critical care services. This led to the expansion of critical care services with the resultant recruitment of large numbers of nurses new to critical care. Northumbria and other Universities within the UK were commissioned to provide formal education to critical care nurses and developed Foundations in Acute and Critical Care Module to provide nurses new to critical care, or from other acute clinical settings, with the knowledge and skills to manage this complex group of patients. The aim of this paper is to share the authors' experience of developing "Criticality" a board game designed to formatively assess learning amongst critical care nurses following a formal taught module in a Higher Education Institution (HEI) and prior to the summative assessment. Author experience suggests that Criticality is a useful revision tool and also fun and interactive which helped the students to identify strengths and weaknesses in their knowledge base and thus direct their revision prior to summative assessment. PMID:23462518

  20. Community translation of the Math Interactive Learning Experience Program for children with FASD.

    PubMed

    Kable, Julie A; Taddeo, Elles; Strickland, Dorothy; Coles, Claire D

    2015-04-01

    The Math Interactive Learning Experience (MILE), a program designed to address academic and behavioral problems found in children with Fetal Alcohol Spectrum Disorders (FASD), was found to be effective in a randomized clinical trials with results that persisted at a 6-month follow-up. The current study evaluated the effectiveness of a community translation, in partnership with several community sites in the metropolitan Atlanta area. A total of 60 participants were randomly assigned to one of the three treatment groups: the MILE program administered at a specialty care center (Center MILE) or in the community (Community MILE), or to parent math instruction only (Parent Instruction). This study evaluated instructor satisfaction with the training program, knowledge related to FASD and the MILE program, adherence to the MILE teaching methodology, participant math outcomes, and parents' satisfaction with their treatment experience. Instructors reported a high degree of satisfaction with the overall training and mean site fidelity ratings were positively correlated with change in math performance. Those in the MILE intervention groups demonstrated more positive gains in math skills than those in the Parent Instruction group but did not differ from each other. Parents in the Parent Instruction group reported less satisfaction with their intervention than those assigned to the Center MILE group but satisfaction ratings did not differ between those in the MILE intervention groups. These results indicate that the community translation and the MILE instructor training program developed as part of this process were well-received and effective in producing positive treatment outcomes. PMID:25601483

  1. Formalizing the potential of stereoscopic 3D user experience in interactive entertainment

    NASA Astrophysics Data System (ADS)

    Schild, Jonas; Masuch, Maic

    2015-03-01

    The use of stereoscopic 3D vision affects how interactive entertainment has to be developed as well as how it is experienced by the audience. The large amount of possibly impacting factors and variety as well as a certain subtlety of measured effects on user experience make it difficult to grasp the overall potential of using S3D vision. In a comprehensive approach, we (a) present a development framework which summarizes possible variables in display technology, content creation and human factors, and (b) list a scheme of S3D user experience effects concerning initial fascination, emotions, performance, and behavior as well as negative feelings of discomfort and complexity. As a major contribution we propose a qualitative formalization which derives dependencies between development factors and user effects. The argumentation is based on several previously published user studies. We further show how to apply this formula to identify possible opportunities and threats in content creation as well as how to pursue future steps for a possible quantification.

  2. Shock-bubble interactions: Features of divergent shock-refraction geometry observed in experiments and simulations

    NASA Astrophysics Data System (ADS)

    Ranjan, Devesh; Niederhaus, John H. J.; Oakley, Jason G.; Anderson, Mark H.; Bonazza, Riccardo; Greenough, Jeffrey A.

    2008-03-01

    The interaction of a planar shock wave with a spherical bubble in divergent shock-refraction geometry is studied here using shock tube experiments and numerical simulations. The particular case of a helium bubble in ambient air or nitrogen (A≈-0.8) is considered, for 1.4experiments are used successfully to evaluate the usefulness of various analytical models, and characteristic dimensionless time scales are developed that collapse temporal trends in these quantities. Those linked directly to baroclinicity tend to follow time scales based on shock wave speeds, while those linked to interface deformation and vortex- or shear-induced motion tend to follow a time scale based on the postshock flow speed, though no single time scale is found to be universally successful.

  3. Study of Nonlinear Interaction and Turbulence of Alfven Waves in LAPD Experiments

    SciTech Connect

    Boldyrev, Stanislav; Perez, Jean Carlos

    2013-11-29

    The complete project had two major goals — investigate MHD turbulence generated by counterpropagating Alfven modes, and study such processes in the LAPD device. In order to study MHD turbulence in numerical simulations, two codes have been used: full MHD, and reduced MHD developed specialy for this project. Quantitative numerical results are obtained through high-resolution simulations of strong MHD turbulence, performed through the 2010 DOE INCITE allocation. We addressed the questions of the spectrum of turbulence, its universality, and the value of the so-called Kolmogorov constant (the normalization coefficient of the spectrum). In these simulations we measured with unprecedented accuracy the energy spectra of magnetic and velocity fluctuations. We also studied the so-called residual energy, that is, the difference between kinetic and magnetic energies in turbulent fluctuations. In our analytic work we explained generation of residual energy in weak MHD turbulence, in the process of random collisions of counterpropagating Alfven waves. We then generalized these results for the case of strong MHD turbulence. The developed model explained generation of residual energy is strong MHD turbulence, and verified the results in numerical simulations. We then analyzed the imbalanced case, where more Alfven waves propagate in one direction. We found that spectral properties of the residual energy are similar for both balanced and imbalanced cases. We then compared strong MHD turbulence observed in the solar wind with turbulence generated in numerical simulations. Nonlinear interaction of Alfv´en waves has been studied in the upgraded Large Plasma Device (LAPD). We have simulated the collision of the Alfven modes in the settings close to the experiment. We have created a train of wave packets with the apltitudes closed to those observed n the experiment, and allowed them to collide. We then saw the generation of the second harmonic, resembling that observed in the

  4. Fluid-matrix interactions during high-temperature aquifer storage - lab experiments and modelling

    NASA Astrophysics Data System (ADS)

    Wismeth, Carina; Ueckert, Martina; Muffler, Selina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    High-temperature aquifer storage is a promising extension to combined heat and power plants because it allows to store excess heat during the summer months and to recuperate the heat in winter when the heat demand exceeds the production. Within a research project funded by the Bavarian State Ministry for Economic Affairs and Media, Energy and Technology and the BMW Group, a pilot scale test was run at the Dingolfing site (Bavaria, Germany) in 2014. Field data and an a priori numerical model suggest dissolution and precipitation of the processes in the calcareous aquifer. In order to quantify the reaction kinetics, lab experiments were run in an autoclave. The experimental results were used to setup and calibrate a numerical hydrogeochemical model based on PhreeqC. Laboratory experiments were performed in a closed system with respect to CO2 and under pre-defined conditions using a high temperature autoclave. Within the dissolution test series original core samples of different depth were heated up with ultrapure water in defined heating cycles up to 110 °C and at defined pressure. For combined dissolution and precipitation processes, tap water from Munich was used. The gas phase was equilibrated with CO2 regarding the pCO2 of tap water. Five water samples were taken for each heating cycle and analyzed by ion chromatography to quantify the calcium/magnesium concentrations and ratio. Additionally the sorption properties of the core materials were tested with respect to the fluorescent dyes used in the field tests. The starting point to model the fluid matrix interactions was literature data of dolomite and calcite rates, which were integrated in the conceptional model. While the model results matched the experimentally determined concentrations nicely, there was a discrepancy with respect to the effective surface areas, which is likely due to impurities of the natural rock materials. The model was able to describe the minor precipitation of calcite during the

  5. Lab Experiments Probe Interactions Between Dilute Pyroclastic Density Currents and 3D Barriers

    NASA Astrophysics Data System (ADS)

    Fauria, K.; Andrews, B. J.; Manga, M.

    2014-12-01

    We conducted scaled laboratory experiments of unconfined dilute pyroclastic density currents (PDCs) to examine interactions between three - dimensional obstacles and dilute PDCs. While it is known that PDCs can surmount barriers by converting kinetic energy into potential energy, the signature of topography on PDC dynamics is unclear. To examine the interplay between PDCs and topography, we turbulently suspended heated and ambient-temperature 20 μm talc powder in air within an 8.5 x 6.1 x 2.6 m tank. Experimental parameters (Froude number, densimetric and thermal Richardson number, particle Stokes and Settling numbers) were scaled such that the experimental currents were dynamically similar to natural PCS. The Reynolds number, however, is much smaller than in natural currents, but still large enough for the flows to be turbulent. We placed cylindrical and ridge-like objects in the path of the currents, illuminated the currents with orthogonal laser sheets, and recorded each experiment with high definition cameras. We observed currents surmounting ridge-like barriers (barrier height = current height). Slanted ridges redirected the currents upward and parallel to the upstream face of the ridges (~45° from horizontal). Down stream of the slanted ridges, ambient-temperature currents reattached to the floor. By comparison, hot currents reversed buoyancy and lifted off. These observations suggest that obstacles enhance air entrainment, a process key to affecting runout distance and the depletion of fine particles in ignimbrites. Moreover, we observed vortex shedding in the wake of cylinders. Our experiments demonstrate that barriers of various shapes affect PDC dynamics and can shorten PDC runout distances. Understanding the effects of topography on PDCs is required for interpreting many deposits because processes such as vortex shedding and topographically-induced changes in turbulent length scales and entrainment likely leave depositional signatures.

  6. Exploring the Affective Inner Experiences of Therapists in Training: The Qualitative Interaction between Session Experience and Session Content

    ERIC Educational Resources Information Center

    Melton, John L.; Nofzinger-Collins, Dawn; Wynne, Martha E.; Susman, Marilyn

    2005-01-01

    Thirty-four 1st-year counseling students recorded their inner experiences following a simulated counseling session. Using a qualitative collective case study approach to extract emotion from a large pool of inner experience, 6 judges identified samples of affect through a triangulation process using intensity, extreme, and critical case sampling…

  7. Infrastructure for genomic interactions: Bioconductor classes for Hi-C, ChIA-PET and related experiments

    PubMed Central

    Lun, Aaron T. L.; Perry, Malcolm; Ing-Simmons, Elizabeth

    2016-01-01

    The study of genomic interactions has been greatly facilitated by techniques such as chromatin conformation capture with high-throughput sequencing (Hi-C). These genome-wide experiments generate large amounts of data that require careful analysis to obtain useful biological conclusions. However, development of the appropriate software tools is hindered by the lack of basic infrastructure to represent and manipulate genomic interaction data. Here, we present the InteractionSet package that provides classes to represent genomic interactions and store their associated experimental data, along with the methods required for low-level manipulation and processing of those classes. The InteractionSet package exploits existing infrastructure in the open-source Bioconductor project, while in turn being used by Bioconductor packages designed for higher-level analyses. For new packages, use of the functionality in InteractionSet will simplify development, allow access to more features and improve interoperability between packages. PMID:27303634

  8. Learning from other people's experience: a neuroimaging study of decisional interactive-learning.

    PubMed

    Canessa, Nicola; Motterlini, Matteo; Alemanno, Federica; Perani, Daniela; Cappa, Stefano F

    2011-03-01

    Decision-making is strongly influenced by the counterfactual anticipation of personal regret and relief, through a learning process involving the ventromedial-prefrontal cortex. We previously reported that observing the regretful outcomes of another's choices reactivates the regret-network. Here we extend those findings by investigating whether this resonant mechanism also underpins interactive-learning from others' previous outcomes. In this functional-Magnetic-Resonance-Imaging study 24 subjects either played a gambling task or observed another player's risky/non-risky choices and resulting outcomes, thus experiencing personal or shared regret/relief for risky/non-risky decisions. Subjects' risk-aptitude in subsequent choices was significantly influenced by both their and the other's previous outcomes. This influence reflected in cerebral regions specifically coding the effect of previously experienced regret/relief, as indexed by the difference between factual and counterfactual outcomes in the last trial, when making a new choice. The subgenual cortex and caudate nucleus tracked the outcomes that increased risk-seeking (relief for a risky choice, and regret for a non-risky choice), while activity in the ventromedial-prefrontal cortex, amygdala and periaqueductal gray-matter reflected those reducing risk-seeking (relief for a non-risky choice, and regret for a risky choice). Crucially, a subset of the involved regions was also activated when subjects chose after observing the other player's outcomes, leading to the same behavioural change as in a first person experience. This resonant neural mechanism at choice may subserve interactive-learning in decision-making. PMID:21126586

  9. Model estimating the effect of marginal ice zone processes on the phytoplankton primary production and air-sea flux of CO2 in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Dvornikov, Anton; Sein, Dmitry; Ryabchenko, Vladimir; Gorchakov, Victor; Martjyanov, Stanislav

    2016-04-01

    This study is aimed to assess the impact of sea ice on the primary production of phytoplankton (PPP) and air-sea CO2 flux in the Barents Sea. To get the estimations, we apply a three-dimensional eco-hydrodynamic model based on the Princeton Ocean Model which includes: 1) a module of sea ice with 7 categories, and 2) the 11-component module of marine pelagic ecosystem developed in the St. Petersburg Branch, Institute of Oceanology. The model is driven by atmospheric forcing, prescribed from the reanalysis NCEP / NCAR, and conditions on the open sea boundary, prescribed from the regional model of the atmosphere-ocean-sea ice-ocean biogeochemistry, developed at Max Planck Institute for Meteorology, Hamburg. Comparison of the model results for the period 1998-2007 with satellite data showed that the model reproduces the main features of the evolution of the sea surface temperature, seasonal changes in the ice extent, surface chlorophyll "a" concentration and PPP in the Barents Sea. Model estimates of the annual PPP for whole sea, APPmod, appeared in 1.5-2.3 times more than similar estimates, APPdata, from satellite data. The main reasons for this discrepancy are: 1) APPdata refers to the open water, while APPmod, to the whole sea area (under the pack ice and marginal ice zone (MIZ) was produced 16 - 38% of PPP); and 2) values of APPdata are underestimated because of the subsurface chlorophyll maximum. During the period 1998-2007, the modelled maximal (in the seasonal cycle) sea ice area has decreased by 15%. This reduction was accompanied by an increase in annual PPP of the sea at 54 and 63%, based, respectively, on satellite data and the model for the open water. According to model calculations for the whole sea area, the increase is only 19%. Using a simple 7-component model of oceanic carbon cycle incorporated into the above hydrodynamic model, the CO2 exchange between the atmosphere and sea has been estimated in different conditions. In the absence of biological

  10. Four-color laser irradiation system for laser-plasma interaction experiments

    SciTech Connect

    Pennington, D.M.; Henesian, M.A.; Wilcox, R.B.

    1996-06-01

    Since 1986, optical smoothing of the laser irradiance on targets for Inertial Confinement Fusion (ICF) has gained increasing attention. Optical smoothing can significantly reduce wavefront aberrations that produce nonuniformities in the energy distribution of the focal spot. Hot spots in the laser irradiance can induce local self focusing of the light, producing filamentation of the plasma. Filamentation can have detrimental consequences on the hydrodynamics of an ICF plasma, and can affect the growth of parametric instabilities, as well as add to the complexity of the study of such instabilities as stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS). As experiments approach and exceed breakeven (i.e., where driver energy = fusion yield), the likelihood of significant excitation of these processes increases. As a result, the authors are including a scheme for implementing optical-beam smoothing for target experiments in the baseline design for the proposed next-generation ICF facility--the National Ignition Facility (NIF). To verify the efficacy of this design for the suppression of parametric instabilites in NIF-like indirect-drive targets, the authors successfully modified a Nova beamline to simulate the proposed NIF conditions. In this article, they discuss the laser science associated with a four-color target campaign on Nova to test the effect of f-number (ratio of focal length to beam diameter) and temporal smoothing on the scaling of SBS with a four-segment interaction beam using NIF-like parameters. The results of the target series associated with the four-color configuration are discussed elsewhere.

  11. A magnetron system for high-flux plasma-surface interaction experiments

    NASA Astrophysics Data System (ADS)

    Emmoth, B.; Ilyinsky, L.; Hultberg, S.; Barchenko, V.; Nasarov, O.

    1997-04-01

    A new compact magnetron plasma system and its characteristics are described. The system makes it possible to carry out ion irradiation experiments at high fluxes of 10 18 ions/cm 2·s and to reach fluences of 10 22 cm -2, with a homogeneous distribution over an area of 0.3 × 0.2 cm 2. The sample temperature, the distribution of ion flux densities within the sputtering zone, and the energy spectrum of ions are in situ measured during irradiation. The device is capable of producing a discharge current of up to 1.2 A and mean current densities of up to 100 mA/cm 2. The mean ion energy can be regulated in the range 50-500 eV by changing the working pressure and the discharge self-sustaining degree. The plasma can be swept over the interaction zone by using a moving magnet controlled by a stepping motor. The VC characteristics and discharge current relations were measured for several different gases and at different pressures in the plasma. Integral ion energy and current density distributions at the cathode surface were measured at different parameters. In the first experiments targets of graphite, silicon, molybdenum and titanium were used and exposed under similar plasma conditions using deuterium in the discharge, energies of 150 eV and fluences of 10 21 cm -2. RBS (Rutherford backscattering spectrometry) and NRA (Nuclear reaction analysis) were analytical techniques for the determination of deposited layers with respect to the quantity of deposits and for the study of the purity and homogeneity of the irradiated layers.

  12. Geophysical variables and behavior: XCVIII. Ambient geomagnetic activity and experiences of "memories": interactions with sex and implications for receptive psi experiences.

    PubMed

    Persinger, M A

    2002-06-01

    During 96 nonsequential days over a 3-yr. period, a total of 53 men and 86 women were exposed only once for 30 min. to transcerebral, weak complex magnetic fields while they sat alone within a quiet chamber. They were asked to record the frequency of specific experiences after the exposure was completed. There was a significant interaction between sex and global geomagnetic activity for the incidence of experiences attributed to memories. Women reported more experiences attributed to "childhood memories" when geomagnetic activity was less than 20 nT, while men reported more of these experiences when the activity was more than 20 nT. Re-analyses of a database of "paranormal experiences" reported by 395 separate individuals over a 100-yr. period indicated that more men than women reported "precognitive experiences" on days the geomagnetic activity was above 20 nT while women reported such experiences if the geomagnetic activity was below 20 nT. These results suggest that these experiences, be they veridical or illusory, may be influenced by global geomagnetic activity that affect the neuroelectrical or neurochemical processes associated with memory consolidation or the attribution of the serial order of experiences during retrieval. PMID:12186249

  13. Cognitive endophenotypes, gene-environment interactions and experience-dependent plasticity in animal models of schizophrenia.

    PubMed

    Burrows, Emma L; Hannan, Anthony J

    2016-04-01

    Schizophrenia is a devastating brain disorder caused by a complex and heterogeneous combination of genetic and environmental factors. In order to develop effective new strategies to prevent and treat schizophrenia, valid animal models are required which accurately model the disorder, and ideally provide construct, face and predictive validity. The cognitive deficits in schizophrenia represent some of the most debilitating symptoms and are also currently the most poorly treated. Therefore it is crucial that animal models are able to capture the cognitive dysfunction that characterizes schizophrenia, as well as the negative and psychotic symptoms. The genomes of mice have, prior to the recent gene-editing revolution, proven the most easily manipulable of mammalian laboratory species, and hence most genetic targeting has been performed using mouse models. Importantly, when key environmental factors of relevance to schizophrenia are experimentally manipulated, dramatic changes in the phenotypes of these animal models are often observed. We will review recent studies in rodent models which provide insight into gene-environment interactions in schizophrenia. We will focus specifically on environmental factors which modulate levels of experience-dependent plasticity, including environmental enrichment, cognitive stimulation, physical activity and stress. The insights provided by this research will not only help refine the establishment of optimally valid animal models which facilitate development of novel therapeutics, but will also provide insight into the pathogenesis of schizophrenia, thus identifying molecular and cellular targets for future preclinical and clinical investigations. PMID:26687973

  14. Characterization of plasma and laser conditions for single hot spot interaction experiments

    SciTech Connect

    Montgomery, D.S.; Johnson, R.P.; Cobble, J.A.; Fernandez, J.C.; Lindman, E.L.; Rose, H.A.; Estabrook, K.G.

    1998-11-01

    The LANL TRIDENT laser system is being used for fundamental experiments which study the interaction of self-focusing, stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in a single (diffraction limited) laser hot spot in order to better understand the coupling between these plasma instabilities. The diffraction limited beam mimics a single hot spot found in speckle distributions that are typical of random or kinoform phase plate (RPP or KPP) smoothing. A long scale length, hot plasma ({approximately} 1 mm, {approximately} 0.5 keV) is created by a separate heater beam, and the single hot spot beam is used to drive parametric instabilities. The focal plane distribution and wavefront of the single hot spot beam are characterized, and the intensity of the single hot spot can be varied between 10{sup 14}--10{sup 16} W/cm{sup 2}. The plasma density, temperature, and flow profiles are measured using gated imaging spectroscopy of collective Thomson scattering. Results of the laser and plasma characterization, and initial results of backscattered SRS, SBS, and beam steering in a flowing plasma are presented.

  15. H I ZEEMAN EXPERIMENTS OF SHOCKED ATOMIC GAS IN TWO SUPERNOVA REMNANTS INTERACTING WITH MOLECULAR CLOUDS

    SciTech Connect

    Koo, Bon-Chul; Heiles, Carl; Stanimirovic, Snezana; Troland, Tom

    2010-07-15

    We have carried out observations of Zeeman splitting of the H I 21 cm emission line from shocked atomic gas in the supernova remnants (SNRs) IC 443 and W51C using the Arecibo telescope. The observed shocked atomic gas is expanding at {approx}100 km s{sup -1} and this is the first Zeeman experiment of such fast-moving, shocked atomic gas. The emission lines, however, are very broad and the systematic error due to baseline curvature hampers an accurate measurement of field strengths. We derive an upper limit of 100-150 {mu}G on the strength of the line-of-sight field component. These two SNRs are interacting with molecular clouds, but the derived upper limits are considerably smaller than the field strengths expected from a strongly shocked dense cloud. We discuss the implications and conclude that either the magnetic field within the telescope beam is mostly randomly oriented or the high-velocity H I emission is from a shocked interclump medium of relatively low density.

  16. CFD Validation Experiment of a Mach 2.5 Axisymmetric Shock-Wave/Boundary-Layer Interaction

    NASA Technical Reports Server (NTRS)

    Davis, David O.

    2015-01-01

    Experimental investigations of specific flow phenomena, e.g., Shock Wave Boundary-Layer Interactions (SWBLI), provide great insight to the flow behavior but often lack the necessary details to be useful as CFD validation experiments. Reasons include: 1.Undefined boundary conditions Inconsistent results 2.Undocumented 3D effects (CL only measurements) 3.Lack of uncertainty analysis While there are a number of good subsonic experimental investigations that are sufficiently documented to be considered test cases for CFD and turbulence model validation, the number of supersonic and hypersonic cases is much less. This was highlighted by Settles and Dodsons [1] comprehensive review of available supersonic and hypersonic experimental studies. In all, several hundred studies were considered for their database.Of these, over a hundred were subjected to rigorous acceptance criteria. Based on their criteria, only 19 (12 supersonic, 7 hypersonic) were considered of sufficient quality to be used for validation purposes. Aeschliman and Oberkampf [2] recognized the need to develop a specific methodology for experimental studies intended specifically for validation purposes.

  17. Trait-mediated interactions: influence of prey size, density and experience.

    PubMed

    McCoy, Michael W; Bolker, Benjamin M

    2008-05-01

    1. The role of non-consumptive predator effects in structuring ecological communities has become an important area of study for ecologists. Numerous studies have shown that adaptive changes in prey in response to a predator can improve survival in subsequent encounters with that predator. 2. Prey-mediated changes in the shapes of predators' functional response surfaces determine the qualitative predictions of theoretical models. However, few studies have quantified the effects of adaptive prey responses on the shape of predator functional responses. 3. This study explores how prey density, size and previous predator experience interact to change the functional response curves of different-sized predators. 4. We use a response surface design to determine how previous exposure to small or large odonate predators affected the short-term survival of squirrel tree frog (Hyla squirella) tadpoles across a range of sizes and densities (i.e. the shape of odonate functional response curves). 5. Predator-induced tadpoles in a given size class did not differ in shape, although induction changed tadpole behaviour significantly. Induced tadpoles survived better in lethal encounters with either predator than did similar-sized predator-naive tadpoles. 6. Induction by either predator resulted in increased survival with both predators at a given size. However, different mechanisms led to increased survival for induced tadpoles. Attack rate for the small predators, whereas handling time increased for the large predators. PMID:18312336

  18. PASP, a high voltage array/plasma interaction experiment. [Photovoltaic Array Space Power

    NASA Technical Reports Server (NTRS)

    Burger, Dale R.

    1991-01-01

    The author discusses the photovoltaic array space power (PASP) experiment, which is designed to obtain data on the interaction between high-voltage photovoltaic arrays and the polar, low-earth plasma environment. Up to six small test arrays (three each of planar and concentrator designs) can be voltage biased over a range of +/- 500 V. During the bias voltage sequence, the array current leakage is measured and array arc events are monitored. If any arcing occurs the arc characteristics will be measured by a transient pulse monitor. An emitter is included to allow voltage bias to be applied to a plasma-charged or uncharged spacecraft. Similarly, the frames of the concentrator arrays can be left floating or can be tied to the negative array terminal. An environmental data scan is made before each bias voltage sequence. This scan collects information on the plasma, array-current-versus-voltage curves, and neutral particle partial pressure. The requirement for high voltages created problems which were met by circuit isolation and logical fault protection.

  19. Structure and interactions in fluids of prolate colloidal ellipsoids: comparison between experiment, theory, and simulation.

    PubMed

    Cohen, A P; Janai, E; Rapaport, D C; Schofield, A B; Sloutskin, E

    2012-11-14

    The microscopic structure of fluids of simple spheres is well known. However, the constituents of most real-life fluids are non-spherical, leading to a coupling between the rotational and translational degrees of freedom. The structure of simple dense fluids of spheroids - ellipsoids of revolution - was only recently determined by direct experimental techniques [A. P. Cohen, E. Janai, E. Mogilko, A. B. Schofield, and E. Sloutskin, Phys. Rev. Lett. 107, 238301 (2011)]. Using confocal microscopy, it was demonstrated that the structure of these simple fluids cannot be described by hard particle models based on the widely used Percus-Yevick approximation. In this paper, we describe a new protocol for determining the shape of the experimental spheroids, which allows us to expand our previous microscopy measurements of these fluids. To avoid the approximations in the theoretical approach, we have also used molecular dynamics simulations to reproduce the experimental radial distribution functions g(r) and estimate the contribution of charge effects to the interactions. Accounting for these charge effects within the Percus-Yevick framework leads to similar agreement with the experiment. PMID:23163381

  20. The VOCALS Regional Experiment: Aerosol-Cloud-Precipitation Interactions in Marine Boundary Layer Cloud

    NASA Astrophysics Data System (ADS)

    Wood, R.

    2012-12-01

    Robert Wood, C.S. Bretherton, C. R. Mechoso, R. A. Weller, B. J. Huebert, H. Coe, B. A. Albrecht, P. H. Daum, D. Leon, A. Clarke, P. Zuidema, C. W. Fairall, G. Allen, S. deSzoeke, G. Feingold, J. Kazil, S. Yuter, R. George, A. Berner, C. Terai, G. Painter, H. Wang, M. Wyant, D. Mechem The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) is an international field program designed to make observations of poorly understood but critical components of the coupled climate system of the southeast Pacific (SEP), a region dominated by strong coastal upwelling, extensive cold SSTs, and home to the largest subtropical stratocumulus deck on Earth. VOCALS-REx took place during October and November 2008 and involved five research aircraft, two ships and two surface sites in northen Chile. A central theme of VOCALS-REx is the improved understanding of links between aerosols, clouds and precipitation and their impacts on marine stratocumulus radiative properties. In this presentation, we will present a synthesis of results from VOCALS-REx focusing on the following questions: (a) how are aerosols, clouds and precipitation inter-related in the SEP region? (b) what microphysical-macrophysical interactions are necessary for the formation and maintenance of open cells? (c) how do cloud and MBL properties change across the strong microphysical gradients from the South American coast to the remote ocean?

  1. Wind tunnel experiments on the interactions between turbulence and small inertial droplets

    NASA Astrophysics Data System (ADS)

    Bateson, Colin; Aliseda, Alberto

    2011-11-01

    Understanding the dynamics of particles in turbulent flows is important to many engineering and environmental problems including spray atomization as well as cloud-droplet growth and precipitation. Specifically, we have studied the effect of turbulence on droplet collision-coalescence in an effort to clarify its role in the process of warm rain formation. We are exploring the hypothesis that turbulence-induced-collisions can explain the size gap between the limit of condensational growth and the onset of gravitational collisions and sedimentation. We use wind tunnel experiments to study the evolution of water droplets in homogeneous, isotropic, slowly decaying grid turbulence. We analyze the process of preferential concentration and the enhanced relative velocity of droplets in the 1-100 micron range due to their inertial interactions with the underlying turbulence. We collect droplet size and velocity data from a Phase Doppler Particle Analyzer (PDPA) to understand the influence of turbulence on the droplet collision kernel, and to quantitatively model it in terms of the Radial Distribution Function. We use high-speed visualizations to obtain two-dimensional droplet velocity fields to validate the PDPA point measurements, and to model the relative velocity distribution as a function of droplet pair spacing and Stokes number. Supported by NSF grant ATM-0731248.

  2. FDDI information management system for centralizing interactive, computerized multimedia clinical experiences in pediatric rheumatology/Immunology.

    PubMed

    Rouhani, R; Cronenberger, H; Stein, L; Hannum, W; Reed, A M; Wilhelm, C; Hsiao, H

    1995-01-01

    This paper describes the design, authoring, and development of interactive, computerized, multimedia clinical simulations in pediatric rheumatology/immunology and related musculoskeletal diseases, the development and implementation of a high speed information management system for their centralized storage and distribution, and analytical methods for evaluating the total system's educational impact on medical students and pediatric residents. An FDDI fiber optic network with client/server/host architecture is the core. The server houses digitized audio, still-image video clips and text files. A host station houses the DB2/2 database containing case-associated labels and information. Cases can be accessed from any workstation via a customized interface in AVA/2 written specifically for this application. OS/2 Presentation Manager controls, written in C, are incorporated into the interface. This interface allows SQL searches and retrievals of cases and case materials. In addition to providing user-directed clinical experiences, this centralized information management system provides designated faculty with the ability to add audio notes and visual pointers to image files. Users may browse through case materials, mark selected ones and download them for utilization in lectures or for editing and converting into 35mm slides. PMID:8591407

  3. Wave-current interaction near the Gulf Stream during the surface wave dynamics experiment

    NASA Technical Reports Server (NTRS)

    Wang, David W.; Liu, Antony K.; Peng, Chih Y.; Meindl, Eric A.

    1994-01-01

    This paper presents a case study on the wave-current interaction near the local curvature of a Gulf Stream meander. The wave data were obtained from in situ measurements by a pitch-roll discus buoy during the Surface Wave Dynamics Experiment (SWADE) conducted off Wallops Island, Virginia, from October 1990 to March 1991. Owing to the advection of the Gulf Stream by the semidiurnal tide, the discus buoy was alternately located outside and inside the Gulf Stream. The directional wave measurements from the buoy show the changes in wave direction, wave energy, and directional spreading when waves encountered the current in the Gulf Stream meanders. A wave refraction model, using the ray-tracing method with an estimated Gulf Stream velocity field and meandering condition, was used to simulate wave refraction patterns and to estimate wave parameters at relative locations corresponding to buoy measurements. The numerical simulation shows that a focusing zone of wave rays was formed near the boundary and behind the crest of a simulated Gulf Stream meander. The focusing of wave rays causes changes in wave direction, increases in wave energy, and decreases in wave directional spreading, which are in good agreement with the results from the buoy measurements.

  4. Interaction of Fast Ions with Global Plasma Modes in the C-2 Field Reversed Configuration Experiment

    NASA Astrophysics Data System (ADS)

    Smirnov, Artem; Dettrick, Sean; Clary, Ryan; Korepanov, Sergey; Thompson, Matthew; Trask, Erik; Tuszewski, Michel

    2012-10-01

    A high-confinement operating regime [1] with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection (NBI) in the C-2 field-reversed configuration (FRC) experiment [2, 3]. We present experimental and computational results on the interaction of fast ions with the n=2 rotational and n=1 wobble modes in the C-2 FRC. It is found that the n=2 mode is similar to quadrupole magnetic fields in its detrimental effect on the fast ion transport due to symmetry breaking. The plasma gun generates an inward radial electric field, thus stabilizing the n=2 rotational instability without applying the quadrupole magnetic fields. The resultant FRCs are nearly axisymmetric, which enables fast ion confinement. The NBI further suppresses the n=2 mode, improves the plasma confinement characteristics, and increases the plasma configuration lifetime [4]. The n=1 wobble mode has relatively little effect on the fast ion transport, likely due to the approximate axisymmetry about the displaced plasma column. [4pt] [1] M. Tuszewski et al., Phys. Rev. Lett. 108, 255008 (2012).[0pt] [2] M. Binderbauer et al., Phys. Rev. Lett. 105, 045003 (2010).[0pt] [3] H.Y. Guo et al., Phys. Plasmas 18, 056110 (2011).[0pt] [4] M. Tuszewski et al., Phys. Plasmas 19, 056108 (2012)

  5. Analysis of selected specimens from the STS-46 Energetic Oxygen Interaction with Materials-3 experiment

    NASA Technical Reports Server (NTRS)

    Golden, Johnny L.; Bourassa, Roger J.; Dursch, Harry W.; Pippin, H. Gary

    1995-01-01

    The Energetic Oxygen Interaction with Materials 3 (EOIM-3) experiment was flown on the STS-46 mission, which was launched on 31 Jul. 1992 and returned 8 Aug. 1992. Boeing specimens were located on both the NASA Marshall Space Flight Center (MSFC) tray and the Ballistic Missile Defense Organization (BMDO) tray integrated by the Jet Propulsion Laboratory (JPL). The EOIM-3 pallet was mounted in the Space Shuttle payload bay near the aft bulkhead. During the mission, the atomic oxygen (AO) exposure levels of specimens in these passive sample trays was about 2.3 x 10(exp 20) atoms/sq cm. The specimens also received an estimated 22 equivalent sun hours of solar exposure. In addition, it appears that the EOIM-3 pallet was exposed to a silicone contamination source and many specimens had a thin layer of silicon based deposit on their surfaces after the flight. The specimens on the MSFC tray included seven solid film lubricants, a selection of butyl rubber (B612) and silicone (S383) o-rings, three indirect scatter surfaces, and Silver/Fluorinated Ethylene Propylene (Ag/FEP) and Chemglaze A276 specimens which had previously flown on trailing edge locations of the Long Duration Exposure Facility (LDEF). The specimens on the JPL tray included composites previously flown on LDEF and two indirect scattering surfaces.

  6. Long-term experiments to better understand soil-human interactions

    NASA Astrophysics Data System (ADS)

    Bormann, B. T.; Homann, P. S.

    2011-12-01

    Interactions between soils and people may be transforming global conditions, but the interactions are poorly understood. Changes in soils have proven difficult to quantify, especially in complex ecosystems manifesting large spatiotemporal variability. Long-term ecosystem experiments that evaluate soil change and demonstrate alternative choices are important to understanding changes, discovering new controls and drivers, and influencing decisions. Inspired by agriculture studies, like Rothamsted, the US Forest Service established in 1990 a network of operational-scale experiments across the Pacific Northwest to evaluate long-term effects of different forest management and disturbance regimes. With a strong experimental design, these experiments are now helping to better understand the long-term effects of managing tree harvesting (clearcutting and thinning), woody debris, and tree and understory species composition, and-serendipitously-the effects of fire. Initial results from the Southern Oregon experimental site indicate surprisingly rapid soil changes in some regimes but not others. We've also learned that rapid change presents challenges to repeat sampling. We present our sample-archive and comparable-layer approaches that seek to accommodate changes in surface elevation, aggregation and disaggregation, and mineral-soil exports. Thinning mature forest stands (80-100 yrs old) did not significantly change soil C in 11-yrs. A small upper-layer C increase was observed after thinning, but it was similar to the control. Significant increases in upper-layer soil N were observed with most treatments, but all increases were similar to the control. Leaving woody debris had little effect. The most remarkable change occurred when mature stands were clearcut and Douglas-firs were planted and tended. Associated with rapid growth of Douglas-fir, an average of 8 Mg C ha-1 was lost from weathered soil 4-18 cm deep. This contrasts with clearcuts where early-seral hardwoods and

  7. Interaction of the 4-rotational gauge field with orbital momentum, gravidiamagnetic effect, and orbital experiment ''Gravity Probe B''

    SciTech Connect

    Babourova, O. V.; Frolov, B. N.

    2010-07-15

    The direct interaction of the 4-rotational (Lorentzian) gauge field with angular orbital momentum of an external field is considered. This interaction appears in a new Poincare gauge theory of gravitation, in which tetrads are not true gauge fields, but represent some functions of the translational and 4-rotational gauge fields. The given interaction leads to a new effect: the existence of an electronic orbit precession under the action of an intensive external gravitational field (gravidiamagnetic effect), and also substantiates the existence of the direct interaction of the proper angular momentum of a gyroscope with the torsion field, which theoretically can be generated by the rotational angular momentum of the planet Earth. The latter interaction can be detected by the experiment Gravity Probe B on the satellite orbit.

  8. Swept shock/boundary layer interaction experiments in support of CFD code validation

    NASA Technical Reports Server (NTRS)

    Settles, G. S.; Lee, Y.

    1990-01-01

    Research on the topic of shock wave/turbulent boundary layer interaction was carried out. Skin friction and surface pressure measurements in fin-induced, swept interactions were conducted, and heat transfer measurements in the same flows are planned. The skin friction data for a strong interaction case (Mach 4, fin-angles equal 16 and 20 degrees) were obtained, and their comparison with computational results was published. Surface pressure data for weak-to-strong fin interactions were also obtained.

  9. English Language Learners' Experiences in Classroom Settings: Understanding Teacher Beliefs, Peer Interaction, and Language Differences

    ERIC Educational Resources Information Center

    Schloegel, Micah Roman

    2015-01-01

    Creating opportunities for students to engage in positive peer interactions is important because these interactions benefit students' motivation to learn, and their social, linguistic, and cognitive development. Peer interactions are particularly important for supporting English language learners' (ELL) because they are often at risk for academic…

  10. Chemical projectile-target interaction during hypervelocity cratering experiments (MEMIN project).

    NASA Astrophysics Data System (ADS)

    Ebert, M.; Hecht, L.; Deutsch, A.; Kenkmann, T.

    2012-04-01

    The detection and identification of meteoritic components in impact-derived rocks are of great value for confirming an impact origin and reconstructing the type of extraterrestrial material that repeatedly stroke the Earth during geologic evolution [1]. However, little is known about processes that control the projectile distribution into the various impactites that originate during the cratering and excavation process, and inter-element fractionation between siderophile elements during impact cratering. In the context of the MEMIN project, cratering experiments have been performed using spheres of Cr-V-Co-Mo-W-rich steel and of the iron meteorite Campo del Cielo (IAB) as projectiles accelerated to about 5 km/s, and blocks of Seeberger sandstone as target. The experiments were carried out at the two-stage acceleration facilities of the Fraunhofer Ernst-Mach-Institute (Freiburg). Our results are based on geochemical analyses of highly shocked ejecta material. The ejecta show various shock features including multiple sets of planar deformations features (PDF) in quartz, diaplectic quartz, and partial melting of the sandstone. Melting is concentrated in the phyllosilicate-bearing sandstone matrix but involves quartz, too. Droplets of molten projectile have entered the low-viscosity sandstone melt but not quartz glass. Silica-rich sandstone melts are enriched in the elements that are used to trace the projectile, like Fe, Ni, Cr, Co, and V (but no or little W and Mo). Inter-element ratios of these "projectile" tracer elements within the contaminated sandstone melt may be strongly modified from the original ratios in the projectiles. This fractionation most likely result from variation in the lithophile or siderophile character and/or from differences in reactivity of these tracer elements with oxygen [2] during interaction of metal melt with silicate melt. The shocked quartz with PDF is also enriched in Fe and Ni (experiment with a meteorite iron projectile) and in Fe

  11. A statistical method to incorporate biological knowledge for generating testable novel gene regulatory interactions from microarray experiments

    PubMed Central

    Larsen, Peter; Almasri, Eyad; Chen, Guanrao; Dai, Yang

    2007-01-01

    Background The incorporation of prior biological knowledge in the analysis of microarray data has become important in the reconstruction of transcription regulatory networks in a cell. Most of the current research has been focused on the integration of multiple sets of microarray data as well as curated databases for a genome scale reconstruction. However, individual researchers are more interested in the extraction of most useful information from the data of their hypothesis-driven microarray experiments. How to compile the prior biological knowledge from literature to facilitate new hypothesis generation from a microarray experiment is the focus of this work. We propose a novel method based on the statistical analysis of reported gene interactions in PubMed literature. Results Using Gene Ontology (GO) Molecular Function annotation for reported gene regulatory interactions in PubMed literature, a statistical analysis method was proposed for the derivation of a likelihood of interaction (LOI) score for a pair of genes. The LOI-score and the Pearson correlation coefficient of gene profiles were utilized to check if a pair of query genes would be in the above specified interaction. The method was validated in the analysis of two gene sets formed from the yeast Saccharomyces cerevisiae cell cycle microarray data. It was found that high percentage of identified interactions shares GO Biological Process annotations (39.5% for a 102 interaction enriched gene set and 23.0% for a larger 999 cyclically expressed gene set). Conclusion This method can uncover novel biologically relevant gene interactions. With stringent confidence levels, small interaction networks can be identified for further establishment of a hypothesis testable by biological experiment. This procedure is computationally inexpensive and can be used as a preprocessing procedure for screening potential biologically relevant gene pairs subject to the analysis with sophisticated statistical methods. PMID

  12. The impact of real-time, Internet experiments versus interactive, asynchronous replays of experiments on high school students science concepts and attitudes

    NASA Astrophysics Data System (ADS)

    Kubasko, Dennis S., Jr.

    The purpose of this study was to investigate whether students' learning experiences were similar or different with an interactive, live connection via the Internet in real-time to an Atomic Force Microscope (AFM) versus a stored replay of AFM experiments. Did the two treatments influence students' attitudes towards the learning experience? Are there differences in students' understandings of viruses and science investigations? In addition, this study investigated treatment effects on students' understandings of the nature of science. The present study drew upon the research that examined students' attitudes toward science, students' views of the nature of science, instructional technology in education, and prior research on the nanoManipulator. Specific efforts have been made to address reform efforts in science education throughout the literature review. Eighty-five high school biology students participated in the nanoManipulator experience (44 males, 41 females, 64 Euro-American, 16 African-American, and 5 of other ethnicities). Two high school classes were randomly selected and administered the interactive, real-time treatment. Two different high school classes were randomly selected and administered the limited-interaction, experimental replay treatment. The intervention occurred over a one-week period. Qualitative and quantitative measures were used to examine the differences between two treatment conditions. Experiential, affective, cognitive, and the nature of science domains were assessed. Findings show that the questions and statements made in synchronous time by the live treatment group were significantly different than students' questions and statements in asynchronous communication. Students in the replay treatment made more statements about what they learned or knew about the experience than did students in the live experience. Students in both groups showed significant gains in understanding viruses (particularly viral dimensionality and shape

  13. Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment

    NASA Astrophysics Data System (ADS)

    de Souza, Cláudio M. D.; Carneiro, Cristine E. A.; Baú, João Paulo T.; da Costa, Antonio C. S.; Ivashita, Flávio F.; Paesano, Andrea; di Mauro, Eduardo; de Santana, Henrique; Holm, Nils G.; Neubeck, Anna; Zaia, Cássia T. B. V.; Zaia, Dimas A. M.

    2013-04-01

    In the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pHPZC decreased and the pHIEP increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not +II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM-EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch

  14. Model-experiment interaction to improve representation of phosphorus limitation in land models

    NASA Astrophysics Data System (ADS)

    Norby, R. J.; Yang, X.; Cabugao, K. G. M.; Childs, J.; Gu, L.; Haworth, I.; Mayes, M. A.; Porter, W. S.; Walker, A. P.; Weston, D. J.; Wright, S. J.

    2015-12-01

    Carbon-nutrient interactions play important roles in regulating terrestrial carbon cycle responses to atmospheric and climatic change. None of the CMIP5 models has included routines to represent the phosphorus (P) cycle, although P is commonly considered to be the most limiting nutrient in highly productive, lowland tropical forests. Model simulations with the Community Land Model (CLM-CNP) show that inclusion of P coupling leads to a smaller CO2 fertilization effect and warming-induced CO2 release from tropical ecosystems, but there are important uncertainties in the P model, and improvements are limited by a dearth of data. Sensitivity an