bluuebunny/crossref_metadata_2025 huggingface dataset:
The Roles of Atmospheric Stochastic Forcing (SF) and Oceanic Entrainment Temperature (Te) in Decadal Modulation of ENSO
Authors: Zhang Rong-Hua , Busalacchi Antonio J. , DeWitt David G.
Published: February 2008

The El Niño–Southern Oscillation (ENSO) has been observed to exhibit decadal changes in its properties; the cause and implication of such changes are strongly debated. Here the authors examine the influences of two particular attributors of the ocean–atmospheric system. The roles of stochastic forcing (SF) in the atmosphere and decadal changes in the temperature of subsurface water entrained into the mixed layer (Te) in modulating ENSO are compared to one another using coupled ocean–atmosphere models of the tropical Pacific climate system. Two types of coupled models are used. One is an intermediate coupled model (ICM) and another is a hybrid coupled model (HCM), both of which consist of the same intermediate ocean model (IOM) with an empirical parameterization for Te, constructed via singular value decomposition (SVD) analysis of the IOM simulated historical data. The differences in the ICM and HCM are in the atmospheric component: the one in the ICM is an empirical feedback model for wind stress (τ), and that in the HCM is an atmospheric general circulation model (AGCM; ECHAM4.5). The deterministic component of atmospheric τ variability, representing its signal response (τSig) to an external SST forcing, is constructed statistically by an SVD analysis from a 24-member ensemble mean of the ECHAM4.5 AGCM simulations forced by observed SST; the SF component (τSF) is explicitly estimated from the ECHAM4.5 AGCM ensemble and HCM simulations. Different SF representations are specified in the atmosphere: the SF effect can be either absent or present explicitly in the ICM, or implicitly in the HCM where the ECHAM4.5 AGCM is used as a source for SF. Decadal changes in the ocean thermal structure observed in the late 1970s are incorporated into the coupled systems through the Te parameterizations for the two subperiods before (1963–79) and after (1980–96) the climate shift (T63–79e and T80–96e), respectively.

The ICM and HCM simulations well reproduce interannual variability associated with El Niño in the tropical Pacific. Model sensitivity experiments are performed using these two types of coupled models with different realizations of SF in the atmosphere and specifications of decadal Te changes in the ocean. It is demonstrated that the properties of ENSO are modulated differently by these two factors. The decadal Te changes in the ocean can be responsible for a systematic shift in the phase propagation of ENSO, while the SF in the atmosphere can contribute to the amplitude and period modulation in a random way. The relevance to the observed decadal ENSO variability in the late 1970s is discussed.
The Influence of Changes in Cloud Cover on Recent Surface Temperature Trends in the Arctic
Authors: Liu Yinghui , Key Jeffrey R. , Wang Xuanji
Published: February 2008

A method is presented to assess the influence of changes in Arctic cloud cover on the surface temperature trend, allowing for a more robust diagnosis of causes for surface warming or cooling. Seasonal trends in satellite-derived Arctic surface temperature under clear-, cloudy-, and all-sky conditions are examined for the period 1982–2004. The satellite-derived trends are in good agreement with trends in the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis product and surface-based weather station measurements in the Arctic. Surface temperature trends under clear and cloudy conditions have patterns similar to the all-sky trends, though the magnitude of the trends under cloudy conditions is smaller than those under clear-sky conditions, illustrating the negative feedback of clouds on the surface temperature trends. The all-sky surface temperature trend is divided into two parts: the first part is a linear combination of the surface temperature trends under clear and cloudy conditions; the second part is caused by changes in cloud cover as a function of the clear–cloudy surface temperature difference. The relative importance of these two components is different in the four seasons, with the first part more important in spring, summer, and autumn, but with both parts being equally important in winter. The contribution of biases in satellite retrievals is also evaluated.
The Impact of Rapid Wind Variability upon Air–Sea Thermal Coupling
Authors: Sura Philip , Newman Matthew
Published: February 2008

The basic effect of extratropical atmosphere–ocean thermal coupling is to enhance the variance of both anomalous sea surface temperatures (SSTs) and air temperatures (AIRT) due to a decreased energy flux between the atmosphere and ocean, called reduced thermal damping. In this paper it is shown that rapidly varying surface winds, through their influence upon the turbulent surface heat fluxes that drive this coupling, act to effectively weaken the coupling and thus partially counteract the reduced thermal damping. In effect, rapid fluctuations in wind speed somewhat insulate the atmosphere and ocean from each other.

The nonlinear relationship between the rapidly varying wind speed anomalies and SST and AIRT anomalies results in a rapidly varying component of the surface heat fluxes. The clear separation between the dynamical time scales of the ocean and atmosphere allows this rapidly varying flux to be simply approximated by a stochastic process in which rapidly varying wind speed is represented as Gaussian white noise whose amplitude is modulated by the more slowly evolving thermal anomalies. Such state-dependent (multiplicative) noise can alter the dynamics of atmosphere–ocean coupling because it induces an additional heat flux term, the noise-induced drift, that effectively acts to weaken both coupling and dissipation. Another key implication of the outlined theory is that air–sea coupling includes both deterministic and stochastic components.

The theory is tested by examining daily observations during extended winter (November–April) at several ocean weather stations (OWSs). Two important results are found. First, multiplicative noise at OWS P effectively decreases the coupling by about one-third, with about a 10% (20%) decrease in the damping of SST (AIRT). This suggests that multiplicative noise may be responsible for roughly half of the AIRT variability at OWS P on subseasonal time scales. Second, OWS observations reveal that joint probability distribution functions of daily averaged SST and AIRT anomalies are significantly non-Gaussian. It is shown that treating the rapidly varying boundary layer heat fluxes as state-dependent noise can reproduce this observed non-Gaussianity. It is concluded that the effect of state-dependent noise is crucial to understand and model atmosphere–ocean coupling.
Assessing Bias and Uncertainty in the HadAT-Adjusted Radiosonde Climate Record
Authors: McCarthy Mark P. , Titchner H. A. , Thorne P. W. , Tett S. F. B. , Haimberger L. , Parker D. E.
Published: February 2008

Uncertainties in observed records of atmospheric temperature aloft remain poorly quantified. This has resulted in considerable controversy regarding signals of climate change over recent decades from temperature records of radiosondes and satellites. This work revisits the problems associated with the removal of inhomogeneities from the historical radiosonde temperature records, and provides a method for quantifying uncertainty in an adjusted radiosonde climate record due to the subjective choices made during the data homogenization.

This paper presents an automated homogenization method designed to replicate the decisions made by manual judgment in the generation of an earlier radiosonde dataset [i.e., the Hadley Centre radiosonde temperature dataset (HadAT)]. A number of validation experiments have been conducted to test the system performance and impact on linear trends.

Using climate model data to simulate biased radiosonde data, the authors show that limitations in the homogenization method are sufficiently large to explain much of the tropical trend discrepancy between HadAT and estimates from satellite platforms and climate models. This situation arises from the combination of systematic (unknown magnitude) and random uncertainties (of order 0.05 K decade−1) in the radiosonde data. Previous assessment of trends and uncertainty in HadAT is likely to have underestimated the systematic bias in tropical mean temperature trends. This objective assessment of radiosonde homogenization supports the conclusions of the synthesis report of the U.S. Climate Change Science Program (CCSP), and associated research, regarding potential bias in tropospheric temperature records from radiosondes.
Potential Predictability of Long-Term Drought and Pluvial Conditions in the U.S. Great Plains
Authors: Schubert Siegfried D. , Suarez Max J. , Pegion Philip J. , Koster Randal D. , Bacmeister Julio T.
Published: February 2008

This study examines the predictability of seasonal mean Great Plains precipitation using an ensemble of century-long atmospheric general circulation model (AGCM) simulations forced with observed sea surface temperatures (SSTs). The results show that the predictability (intraensemble spread) of the precipitation response to SST forcing varies on interannual and longer time scales. In particular, this study finds that pluvial conditions are more predictable (have less intraensemble spread) than drought conditions. This rather unexpected result is examined in the context of the physical mechanisms that impact precipitation in the Great Plains. These mechanisms include El Niño–Southern Oscillation’s impact on the planetary waves and hence the Pacific storm track (primarily during the cold season), the role of Atlantic SSTs in forcing changes in the Bermuda high and low-level moisture flux into the continent (primarily during the warm season), and soil moisture feedbacks (primarily during the warm season). It is found that the changes in predictability are primarily driven by changes in the strength of the land–atmosphere coupling, such that under dry conditions a given change in soil moisture produces a larger change in evaporation and hence precipitation than the same change in soil moisture would produce under wet soil conditions. The above changes in predictability are associated with a negatively skewed distribution in the seasonal mean precipitation during the warm season—a result that is not inconsistent with the observations.
Observations of Cloud, Radiation, and Surface Forcing in the Equatorial Eastern Pacific
Authors: Fairall C. W. , Uttal Taneil , Hazen Duane , Hare Jeffrey , Cronin Meghan F. , Bond Nicholas , Veron Dana E.
Published: February 2008

In this paper the authors report on a study of cloud and surface flux processes in the tropical eastern Pacific Ocean based on a series of ship-based cloud and flux measurements made during fall (1999–2002) and spring (2000–02) maintenance cruises along the 95° and 110°W Tropical Atmosphere Ocean (TAO) buoy lines between 8°S and 12°N. The year-to-year and seasonal variabilities of many of the meteorological and oceanic means are relatively small. However, notable seasonal variability is found in the northern branch of the intertropical convergence zone, the north–south sea surface temperature gradient, and heat fluxes north of the equator. In the fall, the strengthening of the north–south SST contrast enhances convective activity (more and deeper clouds, precipitation, southerly inflow) in the area around 6°N, 95°W; diurnal variations of low cloud fraction were weak. Spring cloud fraction varied significantly over the diurnal cycle with substantially lower cloud fraction during the day south of 5°N. Relatively low average cloud-base heights around the equator are due to chilling of the marine boundary layer over the cold tongue.

Cloud radiative forcing strongly correlates with cloud fraction; clouds in the observation region cool the surface by about 40 W m−2 in both seasons. Cloud forcing estimates from the ship data, the TAO buoys, and International Satellite Cloud Climatology Project (ISCCP) products were combined to form a consensus observation dataset that is compared with the second NCEP reanalysis (NCEP-2) and 40-yr ECMWF Re-Analysis (ERA-40) cloud forcing values. The reanalysis products were within 10 W m−2 of the observations for IR cloud forcing but substantially overestimated the solar cloud forcing, particularly in spring.
Fluctuating Arctic Sea Ice Thickness Changes Estimated by an In Situ Learned and Empirically Forced Neural Network Model
Authors: Belchansky G. I. , Douglas D. C. , Platonov N. G.
Published: February 2008

Sea ice thickness (SIT) is a key parameter of scientific interest because understanding the natural spatiotemporal variability of ice thickness is critical for improving global climate models. In this paper, changes in Arctic SIT during 1982–2003 are examined using a neural network (NN) algorithm trained with in situ submarine ice draft and surface drilling data. For each month of the study period, the NN individually estimated SIT of each ice-covered pixel (25-km resolution) based on seven geophysical parameters (four shortwave and longwave radiative fluxes, surface air temperature, ice drift velocity, and ice divergence/convergence) that were cumulatively summed at each monthly position along the pixel’s previous 3-yr drift track (or less if the ice was <3 yr old). Average January SIT increased during 1982–88 in most regions of the Arctic (+7.6 ± 0.9 cm yr−1), decreased through 1996 Arctic-wide (−6.1 ± 1.2 cm yr−1), then modestly increased through 2003 mostly in the central Arctic (+2.1 ± 0.6 cm yr−1). Net ice volume change in the Arctic Ocean from 1982 to 2003 was negligible, indicating that cumulative ice growth had largely replaced the estimated 45 000 km3 of ice lost by cumulative export. Above 65°N, total annual ice volume and interannual volume changes were correlated with the Arctic Oscillation (AO) at decadal and annual time scales, respectively. Late-summer ice thickness and total volume varied proportionally until the mid-1990s, but volume did not increase commensurate with the thickening during 1996–2002. The authors speculate that decoupling of the ice thickness–volume relationship resulted from two opposing mechanisms with different latitudinal expressions: a recent quasi-decadal shift in atmospheric circulation patterns associated with the AO’s neutral state facilitated ice thickening at high latitudes while anomalously warm thermal forcing thinned and melted the ice cap at its periphery.
Systematic Variation in Wintertime Precipitation in East Asia by MJO-Induced Extratropical Vertical Motion
Authors: Jeong Jee-Hoon , Kim Baek-Min , Ho Chang-Hoi , Noh Yeon-Hee
Published: February 2008

The variations in the wintertime precipitation over East Asia and the related large-scale circulation associated with the Madden–Julian oscillation (MJO) are examined. By analyzing the observed daily precipitation for the period 1974–2000, it is found that the MJO significantly modulates the distribution of precipitation over four East Asian countries; the precipitation rate difference between wet and dry periods over East Asia, when the centers of MJO convective activities are located over the Indian Ocean and western Pacific, respectively, reaches 3–4 mm day−1, which corresponds to the climatological winter-mean value.

Composite analysis with respect to the MJO suggests that the MJO–precipitation relation is mostly explained by the strong vertical motion anomalies near an entrance region of the East Asia upper-tropospheric jet and moisture supply in the lower troposphere. To elucidate different dynamic origins of the vertical motion generated by the MJO, diagnostic analysis of a generalized omega equation is adopted. It is revealed that about half of the vertical motion anomalies in East Asia are induced by the quasigeostrophic forcings by the MJO, while diabatic heating forcings explain a very small fraction, less than 10% of total anomalies.
Initial Tendencies of Cloud Regimes in the Met Office Unified Model
Authors: Williams K. D. , Brooks M. E.
Published: February 2008

The Met Office unified forecast–climate model is used to compare the properties of simulated climatological cloud regimes with those produced in short-range forecasts initialized from operational analyses. The regimes are defined as principal clusters of joint cloud-top pressure–optical depth histograms. In general, the cloud regime properties are found to be similar at all forecast times, including the climatological mean. This suggests that weaknesses in the representation of fast local processes are responsible for errors in the simulation of the cloud regimes. The increased horizontal resolution of the model used for numerical weather prediction generally has little impact on the cloud regimes, although the simulation of tropical shallow cumulus is improved, while the relative frequency of tropical deep convection and cirrus compare less favorably with observations. Analysis of the initial temperature tendency profiles for each cloud regime indicates that some of the initial temperature tendency, which leads to a systematic bias in the model climatology, is associated with a particular cloud regime.
Eddy Heat Flux in the Southern Ocean: Response to Variable Wind Forcing
Authors: Hogg Andrew Mc C. , Meredith Michael P. , Blundell Jeffrey R. , Wilson Chris
Published: February 2008

The authors assess the role of time-dependent eddy variability in the Antarctic Circumpolar Current (ACC) in influencing warming of the Southern Ocean. For this, an eddy-resolving quasigeostrophic model of the wind-driven circulation is used, and the response of circumpolar transport, eddy kinetic energy, and eddy heat transport to changes in winds is quantified. On interannual time scales, the model exhibits the behavior of an “eddy saturated” ocean state, where increases in wind stress do not significantly change the circumpolar transport, but instead enhance the eddy field. This is in accord with previous dynamical arguments, and a recent observational study.

The instantaneous response to increased wind stress is to cool temperatures through increased northward Ekman transport of cool water. But, in the longer term, the enhanced eddy state is more efficient at transporting heat, leading to a warming of the ocean. The total eddy heat flux response is greater than the Ekman transport heat flux in this model by a factor of 2, indicating that coarse (non eddy resolving) models may fail to adequately capture the key processes. The authors also test the model response to long-term changes in wind forcing, including steadily increasing circumpolar wind strength over a 30-yr period. The model shows a response in eddy heat flux, and a change in ocean temperature not dissimilar from observed Southern Ocean warming. These findings suggest that eddy heat flux, energized by increasing wind stress, may be a significant contributor to the observed warming of the Southern Ocean.
Climate Signal Detection Times and Constraints on Climate Benchmark Accuracy Requirements
Authors: Leroy Stephen S. , Anderson James G. , Ohring George
Published: February 2008

Long-term trends in the climate system are always partly obscured by naturally occurring interannual variability. All else being equal, the larger the natural variability, the less precisely one can estimate a trend in a time series of data. Measurement uncertainty, though, also obscures long-term trends. The way in which measurement uncertainty and natural interannual variability interact in inhibiting the detection of climate trends using simple linear regression is derived and the manner in which the interaction between the two can be used to formulate accuracy requirements for satellite climate benchmark missions is shown. It is found that measurement uncertainty increases detection times, but only when considered in direct proportion to natural variability. It is also found that detection times depend critically on the correlation time of natural variability and satellite lifetime. As a consequence, requirements on satellite climate benchmark accuracy and mission lifetime must be directly related to the natural variability of the climate system and its associated correlation times.
Real-Time Extraction of the Madden–Julian Oscillation Using Empirical Mode Decomposition and Statistical Forecasting with a VARMA Model
Authors: Love Barnaby S. , Matthews Adrian J. , Janacek Gareth J.
Published: February 2008

A simple guide to the new technique of empirical mode decomposition (EMD) in a meteorological–climate forecasting context is presented. A single application of EMD to a time series essentially acts as a local high-pass filter. Hence, successive applications can be used to produce a bandpass filter that is highly efficient at extracting a broadband signal such as the Madden–Julian oscillation (MJO). The basic EMD method is adapted to minimize end effects, such that it is suitable for use in real time. The EMD process is then used to efficiently extract the MJO signal from gridded time series of outgoing longwave radiation (OLR) data.

A range of statistical models from the general class of vector autoregressive moving average (VARMA) models was then tested for their suitability in forecasting the MJO signal, as isolated by the EMD. A VARMA (5, 1) model was selected and its parameters determined by a maximum likelihood method using 17 yr of OLR data from 1980 to 1996. Forecasts were then made on the remaining independent data from 1998 to 2004. These were made in real time, as only data up to the date the forecast was made were used. The median skill of forecasts was accurate (defined as an anomaly correlation above 0.6) at lead times up to 25 days.
Internal Hydraulic Jumps and Overturning Generated by Tidal Flow over a Tall Steep Ridge
Authors: Legg Sonya , Klymak Jody
Published: February 2008

Recent observations from the Hawaiian Ridge indicate episodes of overturning and strong dissipation coupled with the tidal cycle near the top of the ridge. Simulations with realistic topography and stratification suggest that this overturning has its origins in transient internal hydraulic jumps that occur below the shelf break at maximum ebb tide, and then propagate up the slope as internal bores when the flow reverses. A series of numerical simulations explores the parameter space of topographic slope, barotropic velocity, stratification, and forcing frequency to identify the parameter regime in which these internal jumps are possible. Theoretical analysis predicts that the tidally driven jumps may occur when the vertical tidal excursion is large, which is shown to imply steep topographic slopes, such that dh/dxN/ω > 1. The vertical length scale of the jumps is predicted to depend on the flow speed such that the jump Froude number is of order unity. The numerical results agree with the theoretical predictions, with finite-amplitude internal hydraulic jumps and overturning forming during strong offslope tidal flow over steep slopes. These results suggest that internal hydraulic jumps may be an important mechanism for local tidally generated mixing at tall steep topography.
Laboratory Studies of Scattering Properties of Polluted Cloud Droplets: Implications for FSSP Measurements
Authors: Diehl Karoline , Huber Günter , Mitra Subir K. , Wendisch Manfred
Published: February 2008

Laboratory experiments were conducted in the Mainz vertical wind tunnel to study the effects of pollutants dissolved or suspended in cloud droplets on the droplet size measurements of a Forward Scattering Spectrometer Probe (FSSP). The FSSP is a widely used instrument to derive microphysical properties of atmospheric clouds. Individual droplets of different well-defined sizes were freely falling at their terminal velocities in the wind tunnel while the intensity of radiation emitted by the He–Ne laser of the FSSP and scattered by the droplets was measured. For this purpose, the FSSP was adapted and mounted to the wind tunnel. The intensity of radiation scattered by the droplets in the FSSP measurement is principally used to derive the droplet size. The droplets contained soluble ammonium sulfate or suspended absorbent graphite particles as pollutants in concentrations that were higher than usually found in atmospheric cloud droplets. The results of the measurements and corresponding simulations indicate that for high pollutant concentrations, the scattered laser radiation detected by the FSSP depends significantly on the refractive index of the droplet (i.e., on the concentration of soluble or insoluble pollutants). However, for the lower pollutant concentrations usually observed in atmospheric cloud droplets, the need for correcting the droplet sizes measured with the FSSP for the effects of the pollutions can be avoided.
Use of a Lidar Forward Model for Global Comparisons of Cloud Fraction between the ICESat Lidar and the ECMWF Model
Authors: Wilkinson Jonathan M. , Hogan Robin J. , Illingworth Anthony J. , Benedetti Angela
Published: February 2008

The performance of the European Centre for Medium-Range Weather Forecasts (ECMWF) model in simulating clouds is evaluated using observations by the Geoscience Laser Altimeter System lidar on the Ice, Cloud, and Land Elevation Satellite (ICESat). To account for lidar attenuation in the comparison, model variables are used to simulate the attenuated backscatter using a lidar forward model. This generates a new model cloud fraction that can then be fairly compared with the ICESat lidar. The lidar forward model and ICESat comparison is performed over 15 days (equivalent to 226 orbits of Earth, or roughly 9 million km) of data. The model is assessed by cloud fraction statistics, skill scores, and its ability to simulate lidar backscatter. The results show that the model generally simulates the occurrence and location of clouds well but overestimates the mean amount when present of the ice cloud by around 10%, particularly in the tropics. The skill of the model is slightly better over the land than over the sea. The model also has some problems representing the amount when present in tropical boundary layer cloud, particularly over land, where there is an underestimate by as much as 15%. Calculations of backscatter reveal that the ECMWF model predicts the lidar backscatter to within 5% on average, for a lidar ratio of 20 sr, apart from in thick ice clouds. Sensitivity tests show that realistic variations in extinction-to-backscatter ratio and effective radius affect the forward modeled mean cloud fraction by no more than 10%.
Orographic Modification of Convection and Flow Kinematics by the Oregon Coast Range and Cascades during IMPROVE-2
Authors: Colle Brian A. , Lin Yanluan , Medina Socorro , Smull Bradley F.
Published: February 2008

This paper describes the kinematic and precipitation evolution accompanying the passage of a cold baroclinic trough over the Central Oregon Coast Range and Cascades during 4–5 December 2001 of the second Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE-2) field project. In contrast to previously documented IMPROVE-2 cases, the 4–5 December event featured weaker cross-barrier winds (15–20 m s−1), weaker moist static stability (Nm < 0.006 s−1), and convective cells that preferentially intensified over Oregon’s modest coastal mountain range. These cells propagated eastward and became embedded within the larger orographic precipitation shield over the windward slopes of the Cascades. The Weather Research and Forecasting Model (version 2.2) at 1.33-km grid spacing was able to accurately replicate the observed evolution of the precipitation across western Oregon. As a result of the convective cell development, the precipitation enhancement over the Coast Range (500–1000 m MSL) was nearly as large as that over the Cascades (1500–2000 m MSL). Simulations selectively eliminating the elevated coastal range and differential land–sea friction across the Pacific coastline illustrate that both effects were important in triggering convection and in producing the observed coastal precipitation enhancement. A sensitivity run employing a smoothed representation of the Cascades illustrates that narrow ridges located on that barrier’s windward slope had a relatively small (<5%) impact on embedded convection and overall precipitation amounts there. This is attributed to the relatively weak gravity wave motions and low freezing level, which limited precipitation growth by riming.
A Climatology of Diurnal and Semidiurnal Surface Wind Variations over the Tropical Pacific Ocean Based on the Tropical Atmosphere Ocean Moored Buoy Array
Authors: Ueyama Rei , Deser Clara
Published: February 2008

Hourly measurements from 51 moored buoys in the Tropical Atmosphere Ocean array (9°N–8°S, 165°E–95°W) during 1993–2004 are used to document the climatological seasonal and annual mean patterns of diurnal and semidiurnal near-surface wind variability over the tropical Pacific Ocean. In all seasons, the amplitude of the semidiurnal harmonic is approximately twice as large as the diurnal harmonic for the zonal wind component, while the diurnal harmonic is at least 3 times as large as the semidiurnal harmonic for the meridional wind component, both averaged across the buoy array. Except for the eastern equatorial Pacific, the semidiurnal zonal wind harmonic exhibits uniform amplitude (∼0.14 m s−1) and phase [maximum westerly wind anomalies ∼0325/1525 local time (LT)] across the basin in all seasons. This pattern is well explained by atmospheric thermal tidal theory. The semidiurnal zonal wind signal is diminished over the cold surface waters of the eastern equatorial Pacific where it is associated with enhanced boundary layer stability. Diurnal meridional wind variations tend to be out of phase north and south of the equator (maximum southerly wind anomalies ∼0700 LT at 5°N and ∼1900 LT at 5°S), while a noon southerly wind anomaly maximum is observed on the equator in the eastern Pacific particularly during the cold season (June–November). The diurnal meridional wind variations result in enhanced divergence along the equator and convergence along the southern border of the intertropical convergence zone ∼0700 LT (opposite conditions ∼1900 LT); the amplitude of the divergence diurnal cycle is ∼5 × 10−7 s−1. The diurnal meridional wind variations are largely consistent with the diurnal pressure gradient force.
Testicular self examination — Knowledge of men attending a large Genito Urinary Medicine clinic
Authors: Handy Pauline , Sankar K. Nathan
Published: February 2008

Objective To elicit the level of knowledge, training and preferences of men in relation to Testicular Self Examination (TSE).

Setting The Genito Urinary Medicine (GUM) department of a large teaching hospital in the North East of England. The open access clinic serves patients from Newcastle upon Tyne, Northumberland, Gateshead and surrounding areas. Newcastle is a city with two universities and therefore a large student population.

We sought to estimate the current knowledge and practice of Testicular Self Examination amongst men attending a large Genito Urinary Medicine Clinic and ascertain whether they performed TSE, if they could articulate the signs or symptoms of testicular cancer, whether they felt instruction on TSE was necessary and who, if anyone, should provide training. This information was obtained using a simple questionnaire distributed to all new male patients attending GUM at Newcastle General Hospital, during a 12-week period in early 2006. Results demonstrated that only 67 (8%) of the men performed TSE as recommended in health education leaflets (monthly) with 576 (67%) carrying it out on a random basis. In total, 980 (98%) of the men felt that all men should be given instruction on TSE, with 59 per cent stating that school was the most appropriate place to receive the training.Whilst almost all men were aware that testicular lumps may be a sign of testicular cancer, few were able to identify any other potential signs or symptoms.
Promoting healthy eating in nursery schoolchildren: A quasi-experimental intervention study
Authors: Korwanich Kanyarat , Sheiham Aubrey , Srisuphan Wichit , Srisilapanan Patcharawan
Published: February 2008

Objective To evaluate the effects of implementing a healthy eating policy on nursery schoolchildren's dietary practices in nurseries in Phrae Province, Thailand.

Design Quasi-experimental action research was used to compare the effects of school healthy eating policy on the diets of nursery schoolchildren in eight intervention and eight matched control schools.

Setting Sample was 219 nursery schoolchildren aged four to five years attending 16 schools in Muang district, Phrae Province, Thailand.

Method School healthy eating policy was implemented in intervention schools with the active participation of the school board members, teachers and parents. Snack intakes of 219 nursery schoolchildren in intervention and control groups were assessed through direct observation by trained observers and a three-day dietary record. Dietary data on snack consumption was collected at baseline and nine months after implementing a healthy eating policy.

Results After nine months, the consumption of every snack item, except non-sugar milk, decreased significantly in intervention schools compared to the baseline ( p < .05), but not in control schools. In intervention schools the mean frequency of intakes per day decreased for cariogenic snacks, fresh fruits, Thai desserts, crispy snacks and sugary drinks. On the other hand, in control schools, the mean frequency of consumption per day of cariogenic snacks, non-sugar milk and crispy snacks increased significantly ( p < .05). In the control schools, no difference was found between baseline and after nine months in consumption of fresh fruit, Thai desserts and sugary drinks consumption.

Conclusion Healthy eating policy for nursery schoolchildren was effective in reducing snack consumption in intervention schools.
Affordability calculations on a health education campaign to promote the use of aspirin in Wales
Authors: Morgan Gareth
Published: February 2008

Aspirin has far-reaching public health potential in reducing the risk of heart attacks, ischemic strokes and possibly cancer. Balanced against this potential are undesirable effects of the drug. It seems reasonable to allow every individual over the age of 50 years to make an informed choice about whether or not to take aspirin. A health education campaign on aspirin via general medical practices might save the Welsh NHS as much as £1m per annum from avoided hospital admissions. In addition, the campaign might save more than one life per week in Wales. The NHS and Local Authorities in Wales have several ways of introducing a health education campaign on aspirin, and the cost per life saved of such a campaign appears comparable to smoking cessation programmes. A health education campaign of aspirin in Wales for individuals aged 50+ years is affordable and reasonable.
Support and education of immigrants with chronically ill children: Identified needs from a case study of Turkish and Kurdish families
Authors: Povlsen Lene , Karlberg Ingvar , Ringsberg Karin C
Published: February 2008

Objective The aim of the study was to analyse how parents of Turkish and Turkish/Kurdish children with diabetes and health care professionals perceived the education and support provided, and to assess what was required to improve the collaboration between the families and the team in order to optimize selfcare and metabolic control.

Design A case study including semi-structured interviews, participant observation and information from medical records.

Setting The study was carried out in Copenhagen, Denmark.

Method The study included 11 children aged 4—17 years of Turkish and Kurdish origin, their parents, the Turkish interpreter and the paediatric diabetes team.

Results The study identified the following factors that might contribute to improve the outcome: 1) Adjusted educational initiatives to promote a better understanding of concepts like chronic disease and selfcare, and to ensure that the content of the education is understood, implemented and maintained; 2) special support to enable parents to deal with practical and emotional problems and conflicts related to diabetes management; 3) closer contact and psychosocial support in order to promote learning and motivation for selfcare as well as promoting attendance at the clinics.

Conclusion Non-western immigrants have a considerable need for special support to help them learn to manage a chronic disease. Health education should aim at bridging the gap between differences related to culture and traditions.
Sustainable participation in regular exercise amongst older people: Developing an action research approach
Authors: Davies Jeanne , Lester Carolyn , O'Neill Martin , Williams Gareth
Published: February 2008

Objective This article describes the Triangle Project's work with a post industrial community, where healthy living activities were developed in response to community members' expressed needs.

Method An action research partnership approach was taken to reduce health inequalities, with local people developing their own activities to address health and well being issues. At the instigation of older women attending a community consultation, a low intensity exercise class was started. Baseline details including weight, self-assessed fitness and mobility problems were recorded. The class branched out into social activities including healthy eating, walks and outings; members controlling the pace and content of both class and spin-off activities via continuous feedback and discussion with the Triangle researcher. Two evaluation events were held using a focus group format.

Findings Barriers to regular participation are discussed, together with the achievement of a sustainable fitness group with evidence of health improvement in an initially `unfit' group. Social aspects were highly valued by participants and contributed to sustainability of the class, which is now run by members without external input.

Limitations Though activities appeared to be sustainable when the Triangle Project ended, no longer term follow-up has been possible due to cessation of funding.

Implications Projects aiming to achieve sustainability should build in provision for longer term follow-up.
Vaccination coverage among kindergarten children in Phoenix, Arizona
Authors: Frimpong Jemima A , Rivers Patrick A , Bae Sejong
Published: February 2008

Objective To evaluate school immunization records and document the immunization coverage and compliance level of children enrolled in kindergarten in Phoenix during the 2001—2002 school year. The purpose was to obtain information on: 1) immunization status by age two; 2) under-immunization in kindergarten; 3) administration error; and 4) transcription error.

Methods Vaccination levels were estimated by conducting a retrospective immunization coverage survey of the immunization records of children in SW, SE, NE, and NW regions of Phoenix. A two-stage cluster design was used. Schools were randomly selected with the regions and students were systematically selected within the schools.

Setting Twelve schools from Phoenix were surveyed. Immunization records for 865 student records were assessed. Children who had incomplete or unknown records were identified. Information on date of birth and dates of vaccination of each dose of vaccine was collected.

Results Of the 857 records included in the analyses, 30.6 per cent were from the NE, 19.9 per cent from the NW, 17.8 per cent from the SE and 31.7 per cent were from the SW. Private school students comprised 18.4 per cent of the sample, 78.3 per cent were from public schools and 3.4 per cent from charter schools. Examining the sample, 30.5 per cent did not have the shots required by age two (four Dtap, three Polio, one MMR), 11.4 per cent of shots were administered before the minimum age and/or interval, 16.0 per cent did not have the shots required for entrance to kindergarten (four Dtap, three Polio, two MMR, three HEP B) and 10.8 per cent of the records contained transcription errors.

Conclusion The data showed that vaccination rates varied by region. None of the schools were in full compliance with the Arizona goal of 95 per cent of all kindergarten students being up to date. The vaccination levels were also below the National 2010 goal of 90 per cent by age two. The high administration error rate indicates that providers need to administer vaccines according to the recommended schedule. Further assessment must be done to determine effective interventions to target specific populations.
Entrepreneurship, Emerging Technologies, Emerging Markets
Authors: Thukral Inderpreet S. , Von Ehr James , Walsh Steven , Groen Aard J. , Van Der Sijde Peter , Akmaliah Adham Khairul
Published: February 2008

Academics and practitioners alike have long understood the benefits, if not the risks, of both emerging markets and emerging technologies.Yet it is only recently that foresighted firms have embraced emerging technologies and emerging markets through entrepreneurial activity. Emerging technologies and emerging markets present both unique challenges and tremendous opportunities for those firms and individuals who focus their search for competitive advantage on them. Here, we provide examples of effective commercial pathways for both intra- and entrepreneurial ventures embracing these phenomena. First, we describe how one intrapreneurial large firm is investigating emerging markets such as India and China (emerging economies) with emerging technologies to create a worldwide business solution power. Then the investigation of an emerging technology is provided, that of nanotechnology, by a small entrepreneurial firm utilizing emerging market skill sets to define and enable worldwide business solutions. Interestingly, both of the respective commercialization strategies are based on competency theory albeit, used differently. Finally, we discuss the ability of large and small firm competency-based strategies to wrest value from the opportunities inherent in emerging markets and technologies.
Entrepreneurship, Innovation, and Wealth Distribution
Authors: Spencer Aron S. , Kirchhoff Bruce A. , White Craig
Published: February 2008

The purpose of this article is to investigate theories that have produced differences in entrepreneurship definitions. We raise this issue because equitable wealth distribution is a fundamental focus of economics. Yet, recent attempts to guide research on entrepreneurship embrace innovation while ignoring the wealth redistribution aspect of entrepreneurship. Schumpeter argues that entrepreneurship means innovation by independently owned start-up firms that cause creative destruction that yields equitable wealth redistribution. Currently, most entrepreneurship scholars focus on innovation, by any firm, as a source of wealth creation without recognizing that redistribution only occurs when innovation originates in new, independently owned firms. In this article, we describe how new micro- and nano-technologies championed by high-tech start-ups redefined the electronics industry, deconstructed the mainframe computer industry and are redefining the pharmaceutical industry today. We suggest entrepreneurship research should focus more on entrepreneurs that form and operate independent new firms.
The Impact of `Incubator' Organizations on Opportunity Recognition and Technology Innovation in New, Entrepreneurial High-technology Ventures
Authors: Cooper Sarah Y. , Park John S.
Published: February 2008

The increasingly important role of SMEs in both regional and national economic development has been widely acknowledged in the economic and entrepreneurship literature.The development of an economic and policy environment supporting new, high-growth, high-technology ventures has become common strategy adopted by many policy makers, as a critical means of promoting future economic growth and job creation. Many of these high-technology, economic development programmes embrace enabling technologies, such as micro- and nanotechnology- based firms.Although nascent entrepreneurs have numerous sources of advice and support as they embark on the venture creation pathway, aspects of an entrepreneur's past and present experience exert a central and often pivotal influence on their ability to engage effectively in opportunity recognition and exploitation of innovative new product technologies.This article argues that the professional/social environment in which an entrepreneur lives and works has a fundamental impact upon their ability to recognize and exploit opportunities.The work explores the innovation process in young high-technology firms and focuses upon the long-term impact of previous employment, in `incubator' organizations, in influencing opportunity recognition and product innovation processes. Findings suggests that incubator organizations fundamentally shape entrepreneurs' technical and commercial experience of markets, strongly influence their attitudes to risk and personal achievement, help develop an intricate network of social capital and resources and, finally, provide critical knowledge of the existence, availability and applicability of technology solutions in new and emerging markets. Issues are explored through in-depth interviews in 31 companies in Aberdeen, Scotland, and Ottawa, Canada, cities with established strengths in technology development in academic, commercial and government research organizations, and a history of successful high-technology firm creation. Implications for theory and policy are discussed, with particular reference to the lessons to be learned to assist the development of sectors based upon newly emerging technologies.
Managing Tensions in a High-tech Start-up
Authors: Groen Aard J. , Wakkee Ingrid A.M. , De Weerd-Nederhof Petra C.
Published: February 2008

Answering the question of how enabling technology-based firms manage tensions in their development process, we focus on tensions related to balancing the need to explore new developments for future performance, with the need to exploit existing capabilities to generate sufficient value in the short term. Based on social system theory, we suggest that entrepreneurs use four types of functions to develop their business: goal attainment, pattern maintenance, social networking and economic optimization. Building sustainable firms requires the development of all four functions and the related types of capital (strategic, cultural, economic and social) up to a certain minimum; they must then be balanced in such a way that the exploration—exploitation tension can be dealt with adequately.Through a case study of the development of a sound measuring sensor, we illustrate the four types of functions and the accumulation of capitals by exploring a set of three propositions.
Acceleration and Extension of Opportunity Recognition for Nanotechnologies and Other Emerging Technologies
Authors: Linton Jonathan D. , Walsh Steven T.
Published: February 2008

Commercialization and transfer of technology from laboratories in academe, government, and industry has only met a fraction of its potential. Many suggest that the processes used are currently more of an art than a science. Here we provide a plausible normative model that is used for idea generation and opportunity recognition developed for and used at Sandia National Laboratories.The resultant `research value-added' process integrates technology description, the dual process model of innovation and a product introduction model.The model and process are presented as is the application of the model to technology developments from a research laboratory that are either potentially disruptive or sustaining.The generalizability of research value-added process to both disruptive and sustaining technologies is key to the success of the model and process. Consequently, it is of value in considering alternative uses for existing products, such as simulation software, or applications or research findings that are disruptive and or emerging technologies, such as nanotechnologies.