bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of El Niño on the Spring Fallout of Asian Bird Species at Attu Island
Authors: Hameed Sultan , Norwood Henry H. , Flanagan Michael , Feldstein Steven , Yang Chien-hsiung
Published: July 2009

Several studies have documented the effect of the recent secular climate warming on the distributions and geographical ranges of birds. Here the authors report the strong impact of a recurring climatic pattern in the equatorial Pacific, the El Niño–Southern Oscillation (ENSO) cycle of warm (El Niño) and cold (La Niña) events, on spring migrants along the Far Eastern flyway in northeast Asia. In El Niño years, an unusually large number of birds that use the flyway are observed at Attu Island, westernmost of the Aleutian Islands, nearly 960 km away from the Asian coast. This study is based on a 20-yr dataset documenting the year-to-year variation of Asian birds arriving on Attu in the spring season and uses a three-phased analytical methodology to examine climate impacts on bird movements and populations.

The authors offer evidence that birds are displaced toward the Attu area in strong eastward-moving storms. They also present results from a reverse trajectory model that was used to simulate trajectories that a sample of Attu arrivals likely followed in reaching the island. In a statistical analysis, it is shown that 79% of the variation of the Asian birds is explained by a single climate variable: sea surface temperature in the eastern equatorial Pacific in the previous fall. It is the rise in sea surface temperature in this region, more than 8000 km from Attu, that characterizes the onset of an El Niño episode.

Examining those years for which there was a strong ENSO signal in the fall, it is found that the following May is characterized by anomalously strong westerly winds in the northwest Pacific, conditions that are appropriate for large Asian bird fallouts at Attu. Because of the time lag between the fall sea surface temperatures in the El Niño region and the spring Asian bird count at Attu, and the strong correlation between these two quantities, the number of Asian birds arriving at Attu in spring is predictable in the previous autumn. Such predictions are presented for several years.
Measuring Woody Encroachment along a Forest–Savanna Boundary in Central Africa
Authors: Mitchard E. T. A. , Saatchi S. S. , Gerard F. F. , Lewis S. L. , Meir P.
Published: July 2009

Changes in net area of tropical forest are the sum of several processes: deforestation, regeneration of previously deforested areas, and the changing spatial location of the forest–savanna boundary. The authors conducted a long-term (1986–2006) quantification of vegetation change in a 5400 km2 forest–savanna boundary area in central Cameroon. A cross-calibrated normalized difference vegetation index (NDVI) change detection method was used to compare three high-resolution images from 1986, 2000, and 2006. The canopy dimensions and locations of over 1000 trees in the study area were measured, and a very strong relationship between canopy area index (CAI) and NDVI was found. Across 5400 km2 12.6% of the area showed significant positive change in canopy cover from 1986 to 2000 (0.9% yr−1) and 7.8% from 2000 to 2006 (1.29% yr−1), whereas <0.4% of the image showed a significant decrease in either period. The largest changes were in the lower canopy cover classes: the area with <0.2 m2 m−2 CAI decreased by 43% in 20 years. One cause may be a recent reduction in fire frequency, as documented by Along Track Scanning Radiometer-2/Advanced ATSR (ATSR-2/AATSR) data on fire frequency over the study area from 1996 to 2006. The authors suggest this is due to a reduction in human pressure caused by urbanization, as rainfall did not alter significantly over the study period. An alternative hypothesis is that increasing atmospheric CO2 concentrations are altering the competitive balance between grasses and trees. These data add to a growing weight of evidence that forest encroachment into savanna is an important process, occurring in forest–savanna boundary regions across tropical Africa.
Reanalysis of 47 Years of Climate in the French Alps (1958–2005): Climatology and Trends for Snow Cover
Authors: Durand Yves , Giraud Gérald , Laternser Martin , Etchevers Pierre , Mérindol Laurent , Lesaffre Bernard
Published: July 2009

Since the early 1990s, Météo-France has used an automatic system combining three numerical models to simulate meteorological parameters, snow cover stratigraphy, and avalanche risk at various altitudes, aspects, and slopes for a number of mountainous regions (massifs) in the French Alps and the Pyrenees. This Système d’Analyse Fournissant des Renseignements Atmosphériques à la Neige (SAFRAN)–Crocus–Modèle Expert de Prévision du Risque d’Avalanche (MEPRA) model chain (SCM), usually applied to operational daily avalanche forecasting, is here used for retrospective snow and climate analysis. For this study, the SCM chain used both meteorological observations and guess fields mainly issued from the newly reanalyzed atmospheric model 40-yr ECMWF Re-Analysis (ERA-40) data and ran on an hourly basis over a period starting in the winter of 1958/59 until recent past winters. Snow observations were finally used for validation, and the results presented here concern only the main climatic features of the alpine modeled snowfields at different spatial and temporal scales. The main results obtained confirm the very significant spatial and temporal variability of the modeled snowfields with regard to certain key parameters such as those describing ground coverage or snow depth. Snow patterns in the French Alps are characterized by a marked declining gradient from the northwestern foothills to the southeastern interior regions. This applies mainly to both depths and durations, which exhibit a maximal latitudinal variation at 1500 m of about 60 days, decreasing strongly with the altitude. Enhanced at low elevations, snow depth shows a mainly negative temporal variation over the study period, especially in the north and during late winters, while the south exhibits more smoothed features. The number of days with snow on the ground shows also a significant general signal of decrease at low and midelevation, but this signal is weaker in the south than in the north and less visible at high elevation. Even if a statistically significant test cannot be performed for all elevations and areas, the temporal decrease is present in all the studied quantities. Concerning snow duration, this general decrease can also be interpreted as a sharp variation of the mean values at the end of the 1980s, inducing a step effect in its time series rather than a constant negative temporal trend. The results have also been interpreted in terms of potential for a viable ski industry, especially in the southern areas, and for different changing climatic conditions. Presently, French downhill ski resorts are economically viable from a range of about 1200 m MSL in the northern foothills to 2000 m in the south, but future prospects are uncertain. In addition, no clear and direct relationship between the North Atlantic Oscillation (NAO) or the ENSO indexes and the studied snow parameters could be established in this study.
Comparative Study of Gaussian Dispersion Formulas within the Polyphemus Platform: Evaluation with Prairie Grass and Kincaid Experiments
Authors: Korsakissok Irène , Mallet Vivien
Published: July 2009

This paper details a number of existing formulations used in Gaussian models in a clear and usable way, and provides a comparison within a single framework—the Gaussian plume and puff models of the air quality modeling system Polyphemus. The emphasis is made on the comparison between 1) the parameterizations to compute the standard deviations and 2) the plume rise schemes. The Gaussian formulas are first described and theoretically compared. Their evaluation is then ensured by comparison with the observations as well as with several well-known Gaussian and computational fluid dynamics model performances. The model results compare well to the other Gaussian models for two of the three parameterizations for standard deviations, Briggs’s and similarity theory, while Doury’s shows a tendency to underestimate the concentrations because of a large horizontal spread. The results with the Kincaid experiment point out the sensitivity to the plume rise scheme and the importance of an accurate modeling of the plume interactions with the inversion layer. Using three parameterizations for the standard deviations and the same number of plume rise schemes, the authors were able to highlight a large variability in the model outputs.
Do Gravity Waves Transport Angular Momentum away from Tropical Cyclones?
Authors: Moon Yumin , Nolan David S.
Published: July 2009

Previous studies have suggested that gravity waves can transport a significantly large amount of angular momentum away from tropical cyclones, as much as 10% of the core angular momentum per hour. These previous studies used the shallow-water equations to model gravity waves radiating outward from rapidly rotating inner-core asymmetries. This issue is reinvestigated with a three-dimensional, nonhydrostatic, linear model of the vortex-anelastic equations. The response of balanced, axisymmetric vortices modeled after tropical cyclones to rotating asymmetric heat sources is examined to assess angular momentum transport by gravity waves radiating away from the core region of the vortices. Calculations show that gravity waves do transport angular momentum away from the vortex core; however, the amount transported is several orders of magnitude smaller than recent estimates.
Insights into Cloud-Top Height and Dynamics from the Seasonal Cycle of Cloud-Top Heights Observed by MISR in the West Pacific Region
Authors: Chae Jung Hyo , Sherwood Steven C.
Published: July 2009

The connection between environmental stability and the height of tropical deep convective clouds is analyzed using stereo cloud height data from the Multiangle Imaging Spectroradiometer (MISR), focusing on the seasonal cycle of clouds over the western Pacific Ocean. Three peaks in cloud-top height representing low, mid-topped, and deep convective clouds are found as in previous studies. The optically thickest cloud heights are roughly 2 km higher on the summer side of the equator, where CAPE is higher, than on the winter side. Overall cloud height, however, is about the same on both sides of the equator, but ∼600 m higher in December–February (DJF) than in June–August (JJA). Because of variations in stratospheric upwelling, temperatures near the tropopause exhibit a significant seasonal cycle, mainly above 13 km. Using an ensemble of simulations by the Weather Research and Forecasting (WRF) cloud-resolving model and a simple overshooting parcel calculation, the authors show that the cloud height variation can be explained by that of near-tropopause stability changes, including influence from heights above 14 km, even though the cloud height peaks only near 12 km. This suggests that mixing above cloud top—not typically accounted for in simple models of convection—is important in setting the height of the laminar (anvil) high clouds that result. The MISR data indicate a seasonal variation in peak cloud-top temperature of ∼5 K, despite the recent proposal that cloud-top heights should track a fixed isotherm. That proposal must therefore be applied with caution to any climate-change scenario that may involve significant changes in stratospheric upwelling.
Characteristics of an African Easterly Wave Observed during NAMMA
Authors: Cifelli Robert , Lang Timothy , Rutledge Steven A. , Guy Nick , Zipser Edward J. , Zawislak Jon , Holzworth Robert
Published: July 2009

The evolution of an African easterly wave is described using ground-based radar and ancillary datasets from three locations in West Africa: Niamey, Niger (continental), Dakar, Senegal (coastal), and Praia, Republic of Cape Verde (oceanic). The data were collected during the combined African Monsoon Multidisciplinary Analyses (AMMA) and NASA AMMA (NAMMA) campaigns in August–September 2006.

Two precipitation events originated within the wave circulation and propagated with the wave across West Africa. Mesoscale convective systems (MCSs) associated with these events were identified at all three sites ahead of, within, and behind the 700-mb wave trough. An additional propagating event was indentified that originated east of the wave and moved through the wave circulation. The MCS activity associated with this event did not show any appreciable change resulting from its interaction with the wave. The MCS characteristics at each site were different, likely due to a combination of life cycle effects and changes in relative phasing between the propagating systems and the position of low-level convergence and thermodynamic instability associated with the wave. At the ocean and coastal sites, the most intense convection occurred ahead of the wave trough where both high CAPE and low-level convergence were concentrated. At the continental site, convection was relatively weak owing to the fact that the wave dynamics and thermodynamics were not in sync when the systems passed through Niamey. The only apparent effect of the wave on MCS activity at the continental site was to extend the period of precipitation activity during one of the events that passed through coincident with the 700-mb wave trough. Convective organization at the land sites was primarily in the form of squall lines and linear MCSs oriented perpendicular to the low-level shear. The organization at the oceanic site was more complicated, transitioning from linear MCSs to widespread stratiform cloud with embedded convection. The precipitation activity was also much longer lived at the oceanic site due to the wave becoming nearly stationary near the Cape Verdes, providing an environment supportive of deep convection for an extended period.
The Great 2006 Heat Wave over California and Nevada: Signal of an Increasing Trend
Authors: Gershunov Alexander , Cayan Daniel R. , Iacobellis Sam F.
Published: July 2009

Most of the great California–Nevada heat waves can be classified into primarily daytime or nighttime events depending on whether atmospheric conditions are dry or humid. A rash of nighttime-accentuated events in the last decade was punctuated by an unusually intense case in July 2006, which was the largest heat wave on record (1948–2006). Generally, there is a positive trend in heat wave activity over the entire region that is expressed most strongly and clearly in nighttime rather than daytime temperature extremes. This trend in nighttime heat wave activity has intensified markedly since the 1980s and especially since 2000. The two most recent nighttime heat waves were also strongly expressed in extreme daytime temperatures. Circulations associated with great regional heat waves advect hot air into the region. This air can be dry or moist, depending on whether a moisture source is available, causing heat waves to be expressed preferentially during day or night. A remote moisture source centered within a marine region west of Baja California has been increasing in prominence because of gradual sea surface warming and a related increase in atmospheric humidity. Adding to the very strong synoptic dynamics during the 2006 heat wave were a prolonged stream of moisture from this southwestern source and, despite the heightened humidity, an environment in which afternoon convection was suppressed, keeping cloudiness low and daytime temperatures high. The relative contributions of these factors and possible relations to global warming are discussed.
Effect of Ocean Gateway Changes under Greenhouse Warmth
Authors: Sijp Willem P. , England Matthew H. , Toggweiler J. R.
Published: July 2009

The role of tectonic Southern Ocean gateway changes in driving Antarctic climate change at the Eocene–Oligocene boundary remains a topic of debate. One approach taken in previous idealized modeling studies of gateway effects has been to alter modern boundary conditions, whereby the Drake Passage becomes closed. Here, the authors follow this approach but vary atmospheric pCO2 over a range of values when comparing gateway configurations. They find a significantly greater sensitivity of Antarctic temperatures to Southern Ocean gateway changes when atmospheric pCO2 is high than when concentrations are low and the ambient climate is cool. In particular, the closure of the Drake Passage (DP) gap is a necessary condition for the existence of ice-free Antarctic conditions at high CO2 concentrations in this coupled climate model. The absence of the Antarctic Circumpolar Current (ACC) is particularly conducive to warm Antarctic conditions at higher CO2 concentrations, which is markedly different from previous simulations conducted under present-day CO2 conditions. The reason for this is the reduction of sea ice associated with higher CO2. Antarctic sea surface temperature and surface air temperature warming due to a closed DP gap reach values around ∼5° and ∼7°C, respectively, for high concentrations of CO2 (above 1250 ppm). In other words, the authors find a significantly greater sensitivity of Antarctic temperatures to atmospheric CO2 concentration when the DP is closed compared to when it is open. The presence of a DP gap inhibits a return to warmer and more Eocene-like Antarctic and deep ocean conditions, even under enhanced atmospheric greenhouse gas concentrations.
Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Heating Profiles
Authors: Grecu Mircea , Olson William S. , Shie Chung-Lin , L’Ecuyer Tristan S. , Tao Wei-Kuo
Published: July 2009

In this study, satellite passive microwave sensor observations from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1 − QR) where Q1 is the apparent heat source and QR is the radiative heating rate in regions of precipitation. The TMI heating algorithm (herein called TRAIN) is calibrated or “trained” using relatively accurate estimates of heating based on spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based on a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically integrated condensation and surface precipitation.

Estimates of Q1 − QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1 − QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structures with sharper and more intense heating peaks than the rawinsonde estimates.
Large-Scale Dynamics of the Meiyu-Baiu Rainband: Environmental Forcing by the Westerly Jet*
Authors: Sampe Takeaki , Xie Shang-Ping
Published: July 2009

Meiyu-baiu is the major rainy season from central China to Japan brought by a zonally elongated rainband from June to mid-July. Large-scale characteristics and environmental forcing of this important phenomenon are investigated based on a reanalysis dataset. The meiyu-baiu rainband is accompanied by a trough of sea level pressure, horizontal shears, and sharp moisture gradients near the surface, a westerly jet tilted northward with height, and large northeastward moisture transport from the south.

The analysis here reveals the westerly jet as an important culprit for meiyu-baiu. Along the rainband, mean ascending motion corresponds well with a band of warm horizontal temperature advection in the midtroposphere throughout summer. This adiabatic induction of upward motion originates from the advection of warm air by the westerlies from the eastern flank of the Tibetan Plateau. The ascending motion both induces convection and is enhanced by the resultant condensational heating. The westerly jet anchors the meiyu-baiu rainband also by steering transient eddies, creating periods conducive to convection through convective instability and adiabatic updrafts. Indeed, in meiyu-baiu, the probability distribution of convective instability shows large spreads and is strongly skewed, with a sharp cutoff on the unstable side resulting from the effective removal of instability by convection. Thus, active weather disturbances in the westerly waveguide explain a paradox that convection is active in the meiyu-baiu rainband while mean convective instability is significantly higher to the south over the subtropical North Pacific warm pool. In addition to the westerly jet, low-level southerly winds over eastern China between the heat low over Asia and the subtropical high pressure belt over the Pacific are another important environmental forcing for meiyu-baiu by supplying moisture. A conceptual model for meiyu-baiu is presented, and its implications for seasonal and interannual variations are discussed.
Evaluating the Simulated Seasonality of Soil Moisture with Earth Observation Data
Authors: Ellis Richard J. , Taylor Christopher M. , Weedon Graham P. , Gedney Nicola , Clark Douglas B. , Los Sietse
Published: July 2009

A critical function of a land surface scheme, used in climate and weather prediction models, is to partition the energy from insolation into sensible and latent heat fluxes. Many use a soil moisture function to control the surface moisture fluxes through the transpiration. The validity and global distribution of the parameters used to calculate this soil moisture stress function are difficult to assess.

This work presents a method to map soil moisture stress globally from an earth observation vegetation index and precipitation data, and it compares the resulting distributions with output from the Joint U.K. Land Environment Simulator (JULES) land surface scheme. A number of model runs with different soil and vegetation parameters are compared. These examine the sensitivity of the seasonality of soil moisture stress, within the model, to the parameterization of soil hydraulic properties and the seasonality of leaf area index in the vegetation.

It is found that the seasonality of soil moisture within the model is more sensitive to the soil hydraulic properties than the leaf area index. The partitioning of throughfall into evaporation and runoff, in the model, is the dominant factor in determining the timing of soil moisture stress.
An Eddifying Parsons Model
Authors: Fox-Kemper Baylor , Ferrari Raffaele
Published: July 2009

The time-mean effects of eddies are studied in a model based on the Parsons–Veronis–Huang–Flierl models of the wind-driven gyre. Much of the analysis used for the steady solutions carries over if the model is cast in terms of the thickness-weighted mean velocity, because then mass transport is nondivergent in the absence of diabatic forcing. The model exemplifies the use of residual mean theory to simplify analysis.

A result of the analysis is a boundary layer width in the case of a rapid upper-layer flow and weak lower-layer flow. This boundary layer width is comparable to an eddy mixing length when the typical eddy velocity is taken to be the long Rossby wave phase speed.

Further analysis of the model illustrates important aspects of eddy behavior, model sensitivity to eddy fluxes, and model sensitivity to frictional parameters.
Estimating Wind Velocities in Mountain Lee Waves Using Sailplane Flight Data*
Authors: Millane R. P. , Stirling G. D. , Brown R. G. , Zhang N. , Lo V. L. , Enevoldson E. , Murray J. E.
Published: July 2009

Mountain lee waves are a form of atmospheric gravity wave that is generated by flow over mountain topography. Mountain lee waves are of considerable interest, because they can produce drag that affects the general circulation, windstorms, and clear-air turbulence that can be an aviation hazard, and they can affect ozone abundance through mixing and inducing polar stratospheric clouds. There are difficulties, however, in measuring the three-dimensional wind velocities in high-altitude mountain waves. Mountain waves are routinely used by sailplane pilots to gain altitude. Methods are described for estimating three-dimensional wind velocities in mountain waves using data collected during sailplane flights. The data used are the logged sailplane position and airspeed (sailplane speed relative to the local air mass). An algorithm is described to postprocess this data to estimate the three-dimensional wind velocity along the flight path, based on an assumption of a slowly varying horizontal wind velocity. The method can be applied to data from dedicated flights or potentially to existing flight records used as sensors of opportunity. The methods described are applied to data from a sailplane flight in lee waves of the Sierra Nevada in California.
Vertical Variability of Near-Surface Salinity in the Tropics: Consequences for L-Band Radiometer Calibration and Validation
Authors: Henocq Claire , Boutin Jacqueline , Reverdin Gilles , Petitcolin François , Arnault Sabine , Lattes Philippe
Published: July 2009

Two satellite missions are planned to be launched in the next two years; the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) and the National Aeronautics and Space Administration (NASA) Aquarius missions aim at detecting sea surface salinity (SSS) using L-band radiometry (1.4 GHz). At that frequency, the skin depth is on the order of 1 cm. However, the calibration and validation of L-band-retrieved SSS will be done with in situ measurements, mainly taken at 5-m depth. To anticipate and understand vertical salinity differences in the first 10 m of the ocean surface layer, in situ vertical profiles are analyzed. The influence of rain events is studied. Tropical Atmosphere Ocean (TAO) moorings, the most comprehensive dataset, provide measurements of salinity taken simultaneously at 1, 5, and 10 m and measurements of rain rate. Then, observations of vertical salinity differences, sorted according to their vertical levels, are expanded through the tropical band (30°S–30°N) using thermosalinographs (TSG), floats, expendable conductivity–temperature–depth (XCTD), and CTD data. Vertical salinity differences higher than 0.1 pss are observed in the Pacific, Atlantic, and Indian Oceans, mainly between 0° and 15°N, which coincides with the average position of the intertropical convergence zone (ITCZ). Some differences exceed 0.5 pss locally and persist for more than 10 days. A statistical approach is developed for the detection of large vertical salinity differences, knowing the history of rain events and the simultaneous wind intensity, as estimated from satellite measurements.
Robust Estimations of Current Velocities with Four-Beam Broadband ADCPs
Authors: Gilcoto M. , Jones Emlyn , Fariña-Busto Luis
Published: July 2009

An extended explanation of the hypothesis and equations traditionally used to transform between four-beam ADCP radial beam velocities and current velocity components is presented. This explanation includes a dissertation about the meaning of the RD Instrument error velocity and a description of the standard beam-to-current components transformation as a least squares solution. Afterward, the variance–covariance matrix associated with the least squares solution is found. Then, a robust solution for transforming radial beam velocities into current components is derived under the formality of a weighted least squares approach. The associated variance–covariance matrix is also formulated and theoretically proves that the modulus of its elements will be generally lower than the corresponding modulus of the variance–covariance matrix associated with the standard least squares solution. Finally, a comparison between the results obtained using the standard least squares solution and the results of the weighted least squares method, using a high-resolution ADCP dataset, is presented. The results show that, in this case, the weighted least squares solution provides variance estimations that are 4% lower over the entire record period (8 days) and 7% lower during a shorter, more energetic period (12 h).
Observing Directional Properties of Ocean Swell with an Acoustic Doppler Current Profiler (ADCP)
Authors: Herbers T. H. C. , Lentz S. J.
Published: July 2009

Acoustic Doppler current profilers (ADCPs) are widely used for routine measurements of ocean currents and waves in coastal environments. These instruments have the basic capability to measure surface wave frequency–directional spectra, but the quality of the estimates is not well understood because of the relatively high noise levels in the velocity measurements. In this study, wave data are evaluated from two 600-kHz ADCP instruments deployed at 20- and 45-m depths on the Southern California continental shelf. A simple parametric estimation technique is presented that provides robust estimates of the gross directional wave properties, even when the data quality is marginal, as was often the case in this benign wave environment. Good agreement of mean direction and (to a lesser degree) directional spreading estimates with measurements from a nearby surface-following buoy confirms that reliable wave information can generally be extracted from ADCP measurements on the continental shelf, supporting the instrument’s suitability for routine wave-monitoring applications.
Frontal and Radar Refractivity Analyses of the Dryline on 11 June 2002 during IHOP
Authors: Wakimoto Roger M. , Murphey Hanne V.
Published: July 2009

An analysis of a dryline that did not initiate convection during the observational period is presented. The dryline was the weakest kinematic boundary observed during the International H2O Project (IHOP), but was associated with a large moisture gradient. Detailed dual-Doppler wind syntheses from an airborne Doppler radar were combined with radar refractivity measurements providing a rare opportunity to examine both the kinematic and moisture characteristics of this boundary. The radar thin line denotes the approximate kinematic position of the dryline and was quasi-linear on this day. In contrast, the moisture pattern across the dryline was more complex than was suggested by the characteristics of the thin line. Prominent in the horizontal plots was the presence of narrow (few kilometers wide) channels of moisture extending 15–20 km into the dry air mass. Past studies have suggested that echo thin lines observed in the clear air can be used as a proxy for delineating the moisture contrast across the dryline. In contrast, the “moisture extrusions” were present even though the thin line was quasi-linear and were located in weak-echo regions along the thin line. It is hypothesized that transverse rolls developed at an angle to the boundary layer winds and intersected the dryline. The kinematic airflow associated with these rolls could have protected the moist tongues from the eroding effect of the dry flow west of the dryline. The moisture extrusions appear to diminish with time as they mix with the surrounding dry air.
Verification of Mesoscale NWP Forecasts of Abrupt Cold Frontal Wind Changes
Authors: Ma Yimin , Huang Xinmei , Mills Graham A. , Parkyn Kevin
Published: July 2009

During a wildfire, a sharp wind change can lead to an abrupt increase in fire activity and change the rate of spread, endangering firefighters working on what had been the flank of the fire. In southeastern Australia, routine forecast of cold-frontal wind change arrival times is a critical component of the fire weather forecasting service, and mesoscale NWP model predictions are integral to this forecast process. An event-based verification method has been developed in order to verify these mesoscale NWP model forecasts of wind changes. The approach is based on fuzzy-rule techniques and objectively determines the timing of significant (fire weather) wind changes from time series of observations at a single surface station.

In this paper these rules are applied to observational and NWP model forecast time series at observation locations over five fire seasons to determine objective “observed wind change times” and “forecast wind change times” for significant frontal wind changes in southeastern Australia. These forecast wind change times are compared with those observed, and also with those determined subjectively by forecasters at the Victorian Regional Forecast Centre. This provides an objective verification of NWP wind change forecasts and a measure of contemporary NWP model skill against which future model improvements may be measured. Case studies of two wind change events at selected stations are also presented to demonstrate some of the strengths, weaknesses, and characteristics of this verification technique.
Same Game, New Tricks
Authors: Pelc Andrzej , Pelc Krzysztof J.
Published: July 2009

The aim of this article is to distinguish between strategies in the Iterated Prisoner’s Dilemma on the basis of their relative performance in a given population set. We first define a natural order on such strategies that disregards isolated disturbances, by using the limit of time-average payoffs. This order allows us to consider one strategy as strictly better than another in some population of strategies. We then determine a strategy σ to be ‘‘robust,’’ if in any population consisting of copies of two types of strategies, σ itself and some other strategy τ, the strategy σ is never worse than τ. We present a large class of such robust strategies. Strikingly, robustness can accommodate an arbitrary level of generosity, conditional on the strength of subsequent retaliation; and it does not require symmetric retaliation. Taken together, these findings allow us to design strategies that significantly lessen the problem of noise, without forsaking performance. Finally, we show that no strategy exhibits robustness in all population sets of three or more strategy types.
A Longitudinal Examination of Father Involvement With Children With Developmental Delays
Authors: Dyer W. Justin , McBride Brent A. , Jeans Laurie M.
Published: July 2009

With a representative sample of U.S. children born in 2001, growth curve modeling was used to investigate the association between father—child involvement and the developmental status of the child. Three groups of children, which varied by timing of developmental delay diagnosis, were compared for father involvement trajectories. These groups of children were compared with each other as well as to a group of children without developmental delays. Group comparisons indicate many more similarities than differences, and implications for service providers are discussed.
Is Your Language a Social Clue? Lexical Markers and Social Identity
Authors: Mange Jessica , Lepastourel Nadia , Georget Patrice
Published: July 2009

This research deals with the interplay between language use and social identity. Social lexical markers used by two leaders of two opposed groups (French and American presidents) on the Second Gulf War were identified. Experimental texts were constructed on this basis and were read by French participants. The authors compared two types of social identity activation, either indirect (in-group vs. out-group lexical markers) or direct (in-group vs. neutral priming). Attitude and intergroup perception were measured on three groups (French, American, and Iraqi). Whereas no effect of direct activation was observed, results notably showed that using out-group marker leads participants to emphasize their in-group attitude, whereas an in-group marker leads them to “open-up” toward out-group attitude. Besides, an interesting in-group bias was evidenced despite the use of negatives outcomes and the three groups’ evaluation. Potential applications for intergroup communication are discussed and theoretical and practical elaborations are proposed.
Permanent Visual Loss Due to Dietary Vitamin A Deficiency in an Autistic Adolescent
Authors: McAbee Gary N. , Prieto Debra M. , Kirby Janet , Santilli Ann Marie , Setty Rajendra
Published: July 2009

Children with autism often have restrictive diets. Here, we report an adolescent with autism who developed dietary vitamin A deficiency because of a restrictive diet. Despite supplementation with vitamin A, some of the visual loss was permanent with optic atrophy. Children with autism who have restrictive diets may need periodic serum vitamin levels assessed.
Magnetic Resonance Imaging Changes in Idiopathic Intracranial Hypertension in Children
Authors: Lim Ming Jin , Pushparajah Kuberan , Jan Wajanat , Calver David , Lin Jean-Pierre
Published: July 2009

To evaluate the usefulness of neuroimaging in children with idiopathic intracranial hypertension, brain magnetic resonance imaging (MRI) scans of children with idiopathic intracranial hypertension and age-matched controls were reviewed. Compared with controls, patients with idiopathic intracranial hypertension had flattening of the posterior sclera in 61% versus 40% of cases, distension of perioptic subarachnoid space in 65% versus 35%, intraocular protrusion of pre-laminar optic nerve in 17% versus 0%, tortuosity of optic nerve in 30% versus 5%, and an empty sella in 26% versus 5% of cases. The presence of 3 or more of the MRI features is 95% specific in predicting idiopathic intracranial hypertension. The observed general anesthetic effect on these neuroimaging features are also minimized when multiple features are taken into account. Magnetic resonance imaging features can assist in suspecting the diagnosis of idiopathic intracranial hypertension in children, provided caution is applied when interpreting imaging performed under a general anesthesia.
Mental Health Consequences in Men Exposed to Sexual Abuse During the War in Croatia and Bosnia
Authors: Loncar Mladen , Henigsberg Neven , Hrabac Pero
Published: July 2009

In the research project on sexual abuse of men during the war in Croatia and Bosnia and Herzegovina, detailed information from 60 victims of such crimes was gathered. The aim of the research was to define key attributes of sexual abuse of men in war as well as consequences it had on the victims. A method of structured interview was used. Also, the statement of each victim was recorded. Victims were exposed to physical torture of their genitals, psycho-sexual torture and physical abuse. The most common symptoms of traumatic reactions were sleep disturbances, concentration difficulties, night-mares and flashbacks, feelings of hopelessness, and different physical stress symptoms such as constant headaches, profuse sweating, and tachycardia. In addition to rape and different methods of sexual abuse, most of the victims were heavily beaten. The conclusion is made that the number of sexually abused men during the war must have been much higher than reported.
Analyzing Conflict Dynamics With the Aid of an Interactive Microworld Simulator of a Fishing Dispute
Authors: Kuperman Ranan D.
Published: July 2009

This article presents findings from a research project that uses an interactive simulator of an imaginary fishing dispute. Subjects operating the simulator play the role of a state leader, while the computer program controls the behavior of a contending state as well as provides all the environmental data associated with the conflict. The simulator is designed to operate in real time according to a predefined set of rules and feedbacks. Therefore, it is not a game, where each party takes turns, but a microworld, where both the operator and the computer opponent can initiate actions independently of one another. Because the subjects are able to learn from experience and improve their policies, it might be expected that they should eventually discover an appropriate policy that maximizes their payoffs. However, experiments with university students reveal that the majority of the subjects fail to reach optimal strategies. It appears that there is a preferred bias toward choosing particular types of strategies that satisfy normative standards, even though these strategies produce lower payoffs.
Social Stories™ Improve the On-Task Behavior of Children With Language Impairment
Authors: Schneider Naomi , Goldstein Howard
Published: July 2009

On-task behaviors are examined for three elementary-aged children who had impaired language and challenging behaviors that compromised their classroom participation and inclusion. A multiple-baseline design across participants was used. Each participant showed improvements in on-task behavior following Social Story™ intervention. Participants generalized and maintained their behaviors following the end of intervention. Results indicate a large effect size and that Social Stories™ might be an effective strategy for increasing on-task behavior for children with impaired language.
Features of gender: An analysis of the visual texts of third grade children
Authors: Albers Peggy , Frederick Tammy , Cowan Kay
Published: July 2009

How do primary students construct understandings of the opposite sex? In what ways do these constructions manifest in the visual texts created in literacy and language arts classrooms? Using visual discourse analysis (Albers, 2007) and scheme analysis (Sonesson, 1988) as interpretive methods, we analyzed the visual texts created by 23 third grade students created at the end of a unit of study in which students explored gender stereotypes. Findings suggest the need for close readings of the graphic, structural, and semantic information conveyed by visual texts that children create in literacy and language arts classes.
Customization Decisions Regarding Performance Management Systems of Multinational Companies
Authors: Claus Lisbeth , Hand Michael L.
Published: July 2009

Performance management (PM) is an important human resource (HR) process for the global organization. There is yet no theoretical framework for identifying the factors that affect customization decisions to standardize or localize PM systems of multinational companies (MNCs). Our purpose is to ascertain the extent of customization of PM systems in MNCs and identify factors that influence customization decisions. We hypothesized that customization of a PM system is a function of global integration, cultural distance and the upstream/downstream nature of PM activities moderated by contextual enterprise variables. A survey was conducted among senior HR practitioners working for the 100 largest companies (by number of employees) in Bulgaria and Romania. Results from a response sample of 97 Bulgarian and Romanian companies indicate that MNCs are already aware of the need for cultural localization of their PM systems and that global integration strategy and specific cultural dimensions — power distance and masculinity — matter more in customization decisions than does overall cultural distance.
Efficacy and safety of muraglitazar: a double-blind, 24-week, dose-ranging study in patients with type 2 diabetes
Authors: Rubin Cindy J. , Viraswami-Appanna Kalyanee , Fiedorek Fred T.
Published: July 2009

Muraglitazar is a dual (α/γ) PPAR activator. Dual receptor activation may improve glycaemic and lipid profiles in patients with type 2 diabetes mellitus.This randomised double-blind trial in 1,477 drug-naive patients with type 2 diabetes compared the efficacy and safety of muraglitazar (0.5, 1.5, 5, 10, and 20 mg) with pioglitazone (15 mg). Endpoints included changes in HbA1C and plasma lipids, last observation carried forward over 24 weeks. At week 24, mean changes from baseline in HbA1C ranged from —0.25% to —1.76% with muraglitazar ( p≤0.0008, 0.5 mg versus each higher muraglitazar dose), compared with —0.57% with pioglitazone. At week 12, tri-glycerides decreased 4—41% with muraglitazar and 9% with pioglitazone. High-density lipoprotein cholesterol increased 6—23% with muraglitazar and 10% with pioglitazone. Oedema-related events occurred with muraglitazar in a dose-dependent incidence (range 9—40%), and at 14% with pioglitazone. Overall, muraglitazar produced simultaneous dose-dependent improvements in glycaemic and lipid parameters in drug-naive patients with type 2 diabetes mellitus.
Hypovitaminosis D in Chinese type 2 diabetes: Lack of impact on clinical metabolic status and biomarkers of cellular inflammation
Authors: Luo C. , Wong J. , Brown M. , Hooper M. , Molyneaux L. , Yue D.K.
Published: July 2009

Objective: Low vitamin D (25 OH vitamin D) is implicated in the development of diabetes and the metabolic syndrome. We examined whether hypovitaminosis D has a clinically significant impact on glycaemia, metabolic status and inflammatory markers in Chinese patients with established type 2 diabetes.

Methods: Characteristics of 109 patients aged over 50 years were stratified by 25 OH vitamin D status. Patients identified as 25 OH vitamin D deficient (≤ 50 nmol/L) received cholecalciferol 2,000 IU daily for three months. Measurement of HbA1c, metabolic syndrome parameters, 25 OH vitamin D, calcium, phosphate, PTH, hsCRP and ferritin were taken at baseline and then 25 OH vitamin D, PTH, calcium, phosphate monthly for three months in those on replacement therapy.

Results: Vitamin D deficiency was common, affecting 36% of patients. There was no impact of hypovitaminosis D on metabolic syndrome status, HbA1c or insulin use (p ≥ 0.4 for all) and no association between 25OHVitD and ferritin or hsCRP (p ≥ 0.3 for all). Neither BMI nor the metabolic syndrome affected the incremental rise in 25OHVitD levels during supplementation.

Conclusion: There is no relationship between hypovitaminosis D and metabolic control or inflammatory markers in established type 2 diabetes.This suggests that at least in Chinese populations, the effect of low vitamin D is not clinically significant once diabetes is established. Future 25OHVitD intervention trials should therefore focus on prevention in pre-diabetes.
Self-management for breathlessness in COPD: the role of pulmonary rehabilitation
Authors: Gysels MH , Higginson IJ
Published: July 2009

Most of the effort of controlling breathlessness happens at home. Therefore, it is important to explore how patients and carers respond to breathlessness, what their self-care entails and what they experience as helpful. Data were collected from a purposive sample of 18 chronic obstructive pulmonary disease patients through participant observation during outpatient consultations and in-depth interviews at a large hospital and in the community in London. Data were analysed with the Grounded Theory approach. As information regarding the management of breathlessness was lacking and access to treatment was difficult, patients reverted to alternative strategies. Some patients developed considerable expertise and managed their symptoms competently within the limits of current care. Patients who coped successfully were involved in pulmonary rehabilitation and had adopted this as a way of life. Benefits and challenges to participation in these programmes were identified. Those patients who self-manage maintain an acceptable quality of life through self-acquired expertise relating to symptoms, medication and help-seeking. Well-being needs to be understood not as the end point, but as a precarious balance needing skilful maintenance and hard work. The findings have implications for notions such as adherence, patient involvement and responsibility in the management of chronic obstructive pulmonary disease.