Search

Through the continuing development of improved detectors and detector arrays, far-infrared/submillimeter astronomical space missions have had enormous successes in recent years. Despite these advances, the diffraction-limited angular resolving power has remained virtually constant. The advent of telescopes with apertures of several meters will improve this capability, but will still leave image resolution many orders of magnitude poorer than in most other spectral ranges. Here we point out that the only foreseeable way to improve image quality to rival that of modern optical telescopes will be with interferometers whose light collectors are connected by tethers. After making the scientific case for high spatial resolution far-infrared/submillimeter imaging and the use of interferometry as the most immediate way of producing results, we discuss recent advances in dynamic analysis and control of tethered formations, and argue that the further development and testing of tethers in space is a first step toward providing improved far-infrared/submillimeter angular resolution and astronomical image quality. [ABSTRACT FROM AUTHOR]

Relative air humidity in hospitals is often perceived as low. This seems to be due to high indoor temperature or high particle concentration in the air. Perception of dry air, and low relative air humidity, can enforce the conditions for the HVAC system design so that the indoor environment can be improved. In this study, conducted in a hospital ward, measurements and questionnaire distribution to nursing staff and patients were carried out under both summer and winter conditions. The results showed that during summer and winter the relative air humidity and the humidity ratio indoors were low, and that both staff and patients perceived the air as dry during those seasons. In order to change these conditions the indoor air has to be humidified. [ABSTRACT FROM AUTHOR]

The main objective of this study was to develop empirical models with different seasonal lead time periods for the long range prediction of seasonal (June to September) Indian summer monsoon rainfall (ISMR). For this purpose, 13 predictors having significant and stable relationships with ISMR were derived by the correlation analysis of global grid point seasonal Sea-Surface Temperature (SST) anomalies and the tendency in the SST anomalies. The time lags of the seasonal SST anomalies were varied from 1 season to 4 years behind the reference monsoon season. The basic SST data set used was the monthly NOAA Extended Reconstructed Global SST (ERSST) data at 2° × 2° spatial grid for the period 1951–2003. The time lags of the 13 predictors derived from various areas of all three tropical ocean basins (Indian, Pacific and Atlantic Oceans) varied from 1 season to 3 years. Based on these inter-correlated predictors, 3 predictor sub sets A, B and C were formed with prediction lead time periods of 0, 1 and 2 seasons, respectively, from the beginning of the monsoon season. The selected principal components (PCs) of these predictor sets were used as the input parameters for the models A, B and C, respectively. The model development period was 1955–1984. The correct model size was derived using all-possible regressions procedure and Mallow’s “Cp” statistics. Various model statistics computed for the independent period (1985–2003) showed that model B had the best prediction skill among the three models. The root mean square error (RMSE) of model B during the independent test period (6.03% of Long Period Average (LPA)) was much less than that during the development period (7.49% of LPA). The performance of model B was reasonably good during both ENSO and non-ENSO years particularly when the magnitudes of actual ISMR were large. In general, the predicted ISMR during years following the El Niño (La Niña) years were above (below) LPA as were the actual ISMR. By including an NAO related predictor (WEPR) derived from the surface pressure anomalies over West Europe as an additional input parameter into model B, the skill of the predictions were found to be substantially improved (RMSE of 4.86% of LPA). [ABSTRACT FROM AUTHOR]

Abstract: The ionospheric electron concentration near E-layer maximum varies with solar activity presumably due to variations of EUV fluxes in the lines 97.7 and 102.6nm and soft X-ray (0.1–10nm) emission. The scale of variations of these fluxes during a solar activity cycle is different for EUV (∼2×) and X-ray (∼5×) emission. The relative contribution R = q x /q u of EUV and soft X-ray emission into an ionization rate q near the E-layer maximum varies with a season and a latitude: R ∼0.16 near the equator at all seasons, but in the middle (∼50°) latitudes it varies from R ∼0.08 in winter to R ∼0.32 in summer. It results in the fact, that a dependence of E-layer critical frequencies f o E on the solar activity level is remarkably different for summer and winter in the middle latitudes, and also differs for low, mid and high latitudes. In linear approximation the slope in equation for f o E dependence on F 10.7 activity index may differ by ∼20% for summer and winter and for low and middle latitudes. Up to the present time this effect has not been taken into account in existing semi-empirical models. A simple analytical formula is proposed, which is “in style” of IRI model, with purpose to take into account this effect. [Copyright &y& Elsevier]

Cluster analysis was used to study seasonal forecast skills of the winter season NCEP seasonal forecast model (SFM) hindcasts over the Pacific–North America (PNA) sector. Two skill scores based on cluster mean and ensemble mean are compared. It was shown that the anomaly correlation coefficients (ACCs) of cluster mean are generally higher than those of the simple ensemble mean. The results indicated that the skill was affected by the existence of multiple atmospheric regimes. Multiple regimes tend to appear more often in near-normal tropical Pacific sea surface temperature (SST) episodes, while a single regime tends to appear during warm/cold episodes. The dissimilarity among the cluster members is small and the number of the dominant cluster members is also small when the tropical SST anomaly is large, suggesting that the external forcing reduces the frequency of occurrence of the multiple regimes. The ACC improvements from the ensemble mean ACCs to the cluster mean ACCs are statistically significant. Thus, the cluster mean can be used as a supplementary tool for seasonal forecasting. [ABSTRACT FROM AUTHOR]

Secondary organic carbon (SOC) is often a significant portion of organic carbon (OC) in ambient particulate matter (PM). The levels and seasonal patterns of SOC in Hong Kong were examined using more than 2000 PM10 measurements made over a 4.5-year period (1998-2002) in a network of ten air quality monitoring stations. The positive matrix factorization (PMF) model was used to analyze this large data set for source identification and apportioning. SOC was subsequently estimated to be the sum of OC present in the secondary sources, i.e., secondary sulfate, secondary nitrate, and secondary organic aerosol. The annual average SOC as estimated by the PMF method was 4.25µg C/m³ while the summer average was 1.66µg C/m³ and the winter average was 7.05µg C/m³. In comparison, the method that uses EC as a tracer for primary carbonaceous aerosol sources to derive SOC overestimated SOC by 70-212% for the summer samples and by 4-43% for the winter samples. The overestimation by the EC tracer method resulted from the inability of obtaining a single OC/EC ratio that represented a mixture of primary sources varying in time and space. We found that SOC and secondary sulfate had synchronous seasonal variation and were correlated in individual seasons, suggesting common factors that control their formation. Additionally, the presence of SOC was found to be enhanced more than that of secondary sulfate in the winter. We postulate this to be a combined result of favorable partitioning of semivolatile SOC species in the particle phase and more abundant SOC precursors in the winter. [ABSTRACT FROM AUTHOR]

The influence of ENSO on intraseasonal variability over the Tanzanian coast during the short (OND) and long (MAM) rainy seasons is examined. In particular, variability in the rainfall onset, peak and end dates as well as dry spells are considered. In general, El Niño appears to be associated with above average rainfall while La Niña is associated with below average rainfall over the northern Tanzanian coast during OND, and to lesser extent MAM. Over the southern coast, the ENSO impacts are less coherent and this region appears to be a transition zone between the opposite signed impacts over equatorial East and southern Africa. The increased north coast rainfall during El Niño years is generally due to a longer than normal rainfall season associated with early onset while reduced rainfall during La Niña years tends to be associated with a late onset, and thus a shorter than average rainfall season. Wet conditions during El Niño years were associated with enhanced convection and low-level easterly anomalies over the equatorial western Indian Ocean implying enhanced advection of moisture from the Indian Ocean while the reverse is true for La Niña years. Hovmöller plots for OLR and zonal wind at 850 hPa and 200 hPa show eastward, westward propagating and stationary features over the Indian Ocean. It was observed that the propagating features were absent during strong El Niño years. Based on the Hovmöller results, it is observed that the convective oscillations over the Tanzanian coast have some of the characteristic features of intraseasonal oscillations occurring elsewhere in the tropics. [ABSTRACT FROM AUTHOR]

Abstract. In a theoretical framework, the development time of arthropods is closely associated with population growth, so that strong selection pressure may be imposed on development patterns. In this context, selection towards shorter development times may act on female mites in the season when population size is growing. In contrast, such selective pressure may be weaker just before hibernation, because the stage adjustment may be more important than population growth in such seasons. Thus, selection to shorten development times may act more strongly in long daylength conditions, so that different developmental responses among the seasons (reaction norm) may evolve. I predicted that the development time is shorter under the long-day conditions of population-growing seasons than under the short-day conditions of hibernating seasons, and that genetic variation at the long-day is smaller than that at the short-day. In order to test this prediction, the egg-to-adult development time of a population of Tetranychus kanzawai (Acari: Tetranychidae) was investigated under short (9L:15D) and long (15L:9D) daylength conditions at 18 °C. In addition, genetic variation in female development times under these conditions was estimated by using half-sib design. The development time of females at short day was 1 day longer than at long day under the experimental conditions. Male development times follow the pattern of females with <1 day delay. However, heritabilities under these two treatments were quite low and neither was significant. Thus, only the first prediction was supported by the results. In addition, maternal and/or non-additive effects in the female development time were highly significant under both daylength conditions examined. [ABSTRACT FROM AUTHOR]

This study assesses the sensitivity of the fully coupled NCAR-DOE PCM to three different representations of present-day land cover, based on IPCC SRES land cover information. We conclude that there is significant model sensitivity to current land cover characterization, with an observed average global temperature range of 0.21 K between the simulations. Much larger contrasts (up to 5 K) are found on the regional scale; however, these changes are largely offsetting on the global scale. These results show that significant biases can be introduced when outside data sources are used to conduct anthropogenic land cover change experiments in GCMs that have been calibrated to their own representation of present-day land cover. We conclude that hybrid systems that combine the natural vegetation from the native GCM datasets combined with human land cover information from other sources are best for simulating such impacts. We also performed a prehuman simulation, which had a 0.39 K ~higher average global temperature and, perhaps of greater importance, temperature changes regionally of about 2 K. In this study, the larger regional changes coincide with large-scale agricultural areas. The initial cooling from energy balance changes appear to create feedbacks that intensify mid-latitude circulation features and weaken the summer monsoon circulation over Asia, leading to further cooling. From these results, we conclude that land cover change plays a significant role in anthropogenically forced climate change. Because these changes coincide with regions of the highest human population this climate impact could have a disproportionate impact on human systems. Therefore, it is important that land cover change be included in past and future climate change simulations. [ABSTRACT FROM AUTHOR]

A data set of the fractional green vegetation cover (FGREEN) for the Conterminous USA was evaluated for regional and seasonal variation. The value of FGREEN was derived monthly for the three most dominant land cover classes per 20 km by 20 km grid cell within the study area. At this grid cell resolution (comprised of 400 1-km pixels), 97 percent of the grid cells included three or fewer land cover classes. FGREEN was found to vary regionally due to local land cover and climate variations. FGREEN was found significantly different between one or more of the land cover classes, for one or more months, in 58 percent of the grid cells included in the study. Monthly FGREEN values for the land cover classes vary sufficiently between the land cover classes to warrant monthly FGREEN data for each of the one to three most dominant land cover classes per grid cell. [ABSTRACT FROM AUTHOR]

The seasonal cycle of the zonal-mean zonal momentum balance in the Tropics is investigated using NCEP reanalysis data. It is found that the climatological stationary waves in the tropical upper troposphere, which are dominated by the equatorial Rossby wave response to tropical heating, produce an equatorward eddy flux of westerly momentum in the equatorial belt. The resulting westerly acceleration in the tropical upper troposphere is balanced by the advection of easterly momentum associated with the cross-equatorial mean meridional circulation. The eddy momentum fluxes and the cross-equatorial flow both tend to be strongest during the monsoon seasons, when the maximum diabatic heating is off the equator, and weakest during April–May, the season of strongest equatorial symmetry of the heating. The upper-level Rossby wave pattern exhibits a surprising degree of equatorial symmetry and follows a similar seasonal progression. Solutions of the nonlinear shallow water wave equation also show a predominantly equatorially symmetric response to a heat source centered off the equator. [ABSTRACT FROM AUTHOR]

Abstract: While Peter the Great (ruled c1694–1725) can be credited with a concerted attempt to introduce modern European science, technology and other achievements to Russia, the fact that he built upon earlier processes of change which tended in the same direction is frequently underemphasized. The paper challenges the idea that Russia was totally isolated and static before Peter, but emphasizes the very different context in which science, technology and related pursuits developed there by comparison with Europe. It is asserted that the effects of state building in both the European and Russian cases gave rise to certain parallels and similarities. Using mapmaking as an example the paper suggests that its growing importance in both regions during this period was a reflection of the requirements of state building and not merely a product of the rise of commercial capitalism (the latter being as yet relatively insignificant in Russia). The frequently postulated links between commercial capitalism, the rise of mathematical sciences and a growing interest in mapmaking are questioned as being largely inapplicable to Russia before Peter and sometimes overstressed in the case of Europe. The paper presents an analysis of the early seventeenth century Book of the Great Map, a written artefact of pre-Petrine cartography which reflects the priorities and also some of the limitations of Russian mapmaking during the period. [Copyright &y& Elsevier]

The precipitation variability over the eastern Amazon (EAM) and northeast Brazil (NEB) during the autumn rainy season (March to May) is diagnosed using raingauge-based weekly data from 1982 to 2001. Since precipitation in this region is remarkably modulated by the combined effects of the Pacific and Atlantic Sea Surface Temperature (SST) anomalies, two extreme and contrasting large-scale climatic scenarios are considered in this study. The unfavorable (UNFAV) scenario, defined by the simultaneous occurrences of the El Niño and northward SST gradient in the intertropical Atlantic and the favorable (FAV) scenario, by the simultaneous occurrence of the La Niña and southward SST gradient in the intertropical Atlantic. UNFAV (FAV) composites with unfiltered data show remarkable changes in both the Walker and the Hadley cells associated with the Atlantic Intertropical Convergence Zone (ITCZ) anomalously weakened (enhanced) thus with deficient (abundant) seasonal rainfall in most of the EAM/NEB. Precipitation variability is identified objectively through EOF analyses performed on the (30–70 day) intraseasonal and submonthly (蠄21 day) filtered weekly precipitation anomalies for 18 autumn seasons (1983 to 2000). The principal components (PC) of the first mode of each analysis show strong oscillations. In particular, the oscillations of the PC series during UNFAV and FAV years reveal that events with anomalously deficient and abundant precipitation over the EAM/NEB occur alternately, even under extreme climatic conditions in the tropical Pacific and Atlantic. Composites based on events with anomalously increased precipitation (objectively selected from the PC series) on intraseasonal and submonthly scales are analyzed separately for the UNFAV and FAV years. These analyses show that for both scenarios the more important rainfall-producing atmospheric mechanism over the EAM/NEB on intraseasonal time scales consists of the establishment of deep convective bands trigged by South Atlantic Convergence Zone events or persistent frontal systems over northeast Brazil. Such a regional pattern is embedded in a large-scale dynamic environment related to the propagation of the Madden-Julian Oscillation over tropical South America. On the other hand, the main rainfall-producing atmospheric mechanism over the EAM/NEB on submonthly time scales is the Atlantic ITCZ during FAV years, whilst weakened Atlantic ITCZ activity may be forced by meridionally elongated mid-latitude wave trains in the upper troposphere during UNFAV years. [ABSTRACT FROM AUTHOR]

An assessment of sewage workers' exposure to airborne cultivable bacteria, fungi and inhaled endotoxins was performed at 11 sewage treatment plants. We sampled the enclosed and unenclosed treatment areas in each plant and evaluated the influence of seasons (summer and winter) on bioaerosol levels. We also measured personal exposure to endotoxins of workers during special operation where a higher risk of bioaerosol inhalation was assumed. Results show that only fungi are present in significantly higher concentrations in summer than in winter (2331 ± 858 versus 329 ± 95 CFU m−3). We also found that there are significantly more bacteria in the enclosed area, near the particle grids for incoming water, than in the unenclosed area near the aeration basins (9455 ± 2661 versus 2435 ± 985 CFU m−3 in summer and 11 081 ± 2299 versus 2002 ± 839 CFU m−3 in winter). All bioaerosols were frequently above the recommended values of occupational exposure. Workers carrying out special tasks such as cleaning tanks were exposed to very high levels of endotoxins (up to 500 EU m−3) compared to routine work. The species composition and concentration of airborne Gram-negative bacteria were also studied. A broad spectrum of different species within the Pseudomonadaceae and the Enterobacteriaceae families were predominant in nearly all plants investigated. [ABSTRACT FROM AUTHOR]

A replicated trial of eleven cultivars was planted at Simcoe, Ontario in 1991. Plants were first harvested in 1994. After eight harvest seasons, 'Bluegold' was the highest yielding cultivar, averaging 6.8 t/ha, and 'Toro' had the largest berries, averaging 1.81 g per berry. 'Bluetta' was the earliest cultivar with on average 50% of its yield picked by 16 July and 'Elliott' the latest, with on average 50% of its yield picked by 27 August. Overall, 'Duke' proved to have the best combination of characteristics of the early cultivars, and 'Nelson' was the most impressive late cultivar. [ABSTRACT FROM PUBLISHER]

Water and particles from three sites located in Halifax Harbour, near and further away from combined municipal sewage effluents (CMSE) were analysed for parental and alkylated polycyclic aromatic hydrocarbons (par and alkPAH). Bioavailability of PAH was compared for inter-tidal mussels collected at the same sites in April and November. The PAH fingerprint determined over 9 sampling times covering a period of 19 months differed more between phases (water and particles) and seasons, than between sites. In the spring, more alkPAH associated with diesel and gasoline were detected in the soluble phase, along with more bioaccumulation of alkPAH in inter-tidal mussels. A broader number of parPAH were detected in mussels collected in the fall. The mean sum of dissolved alkPAH concentrations was higher in water at the site closer to raw CMSE than at the other two sites and particles of that site. However, lowest bioconcentration factors (BCF) were determined in mussels of this more contaminated site. Similar biota-particle accumulation factors (BPAF) were determined for parPAH in mussels from the three sites, all lower than the BCF of alkPAH. The study indicates that sewage treatment plants will reduce the amount of parPAH especially larger than fluoranthene and pyrene from being deposited in the harbour; that alk naphthalenes and fluorenes present in water will continue to be discharged; that the disturbance of sediments can make particle-bound PAH available to mussels. [Copyright &y& Elsevier]

Discusses the misconceptions surrounding seasonal change. Role of the sun to the changes in seasons; Information on calculating the temperature of the planet; Importance of the oceans to the regulation of the seasons.

Daily temperature anomaly records are analyzed (61 for Australia, 18 for Hungary) by means of detrended fluctuation analysis. Positive long range asymptotic correlations extending up to 5-10 years are detected for each case. Contrary to earlier claims, the correlation exponent is not universal for continental stations. Interestingly, the dominant factor is geographic latitude over Australia: the general tendency is a decrease of correlation exponent with increasing distance from the equator. This tendency is in a complete agreement with the results found by Tsonis et al (1999) for 500-hPa height anomalies in the northern hemisphere. The variance of fluctuations exhibits an opposite trend, the larger is the distance from the equator, the larger the amplitude of intrinsic fluctuations. The presence of Tropospheric Biennial Oscillation is clearly identified for three stations at the northeastern edge of the Australian continent. [ABSTRACT FROM AUTHOR]

In this paper, we describe the results of 44 case study analyses of synoptic scale data sets that define the atmospheric structure prior to the development of accident-producing turbulence. First, the 44 case studies are categorized as a function of the location, altitude, time of year, time of day, and turbulence environment, i.e., in clear air, cloudiness, convection, near mountains, or in the proximity of deep convection. It is noteworthy that this later category was much more ubiquitous than was anticipated. Second, NCEP Reanalysis data sets as well as both visible and infrared satellite imagery are employed to diagnose “predictor” fields associated with the synoptic-scale environment preceding severe turbulence. These predictor fields are calculated based on jet stream configuration, kinematic, dynamical, and thermodynamic analyses of the synoptic-scale atmosphere.The results of these analyses indicate a prevalence of severe accident-producing turbulence within the entrance region of the polar or subtropical jet stream at the synoptic-scale. Typically, there is a region of flow curvature located just upstream within the jet entrance region, convection is present within 100?km of the accident, the vertical motion is upward typically within the curved entrance region, absolute vorticity is low, the vertical wind shear is increasing with time, and horizontal cold air advection is substantial. Not all of the 44-case studies conform to this entrance region paradigm. However, most do and the most consistent predictor of severe turbulence is upstream curvature in the synoptic-scale flow. Nearby convection is the second most ubiquitous predictor field. Upward vertical motion, low absolute vorticity, and horizontal cold air advection are all typical predictors in case studies occurring both within the entrance and exit regions of the polar or subtropical jet stream. [ABSTRACT FROM AUTHOR]

Simulation experiments reveal key processes that organize a hydrostatic environment conducive to severe turbulence. The paradigm requires the juxtaposition of the entrance region of a curved jet streak, which is highly subgeostrophic, with the entrance region of a straight jet streak, which is highly supergeostrophic. The wind and mass fields become misphased as the entrance regions converge, resulting in significant spatial variation of inertial forcing, centripetal forcing, as well as along and cross-stream pressure gradient forcing over a meso-ß scale region. Maxima of these forces are misphased where the two dissimilar jet streaks converge and geostrophic balance is disrupted. Velocity divergence within the subgeostrophic region of largest upstream-directed pressure gradient force and velocity convergence near the region of largest downstream-directed centripetal/inertial-advective forcing act to produce a mesoscale front due to spatially varying confluent flow flanked by zones of increasing velocity divergence. This results in frontogenesis as well as the along-stream divergence of cyclonic and convergence of cyclonic ageostrophic vertical vorticity. The nonuniform centripetally forced mesoscale front becomes the locus of large gradients of ageostrophic vertical vorticity along an overturning isentrope. This region becomes favorable for streamwise vorticity gradient formation enhancing the environment for the organization of horizontal vortex tubes in the presence of buoyant forcing. This is because the mesoscale convergence of vertical vorticity on an overturning isentropic surface creates vertical rotation for the development of horizontal vorticity in regions where isentropic surfaces overturn. Vorticity, shear, and buoyancy are focused in one location by this front thus favoring an environment favorable for microvortex formation leading to turbulence. [ABSTRACT FROM AUTHOR]

This paper reports on a small-scale pilot experiment held early in the dry season near Darwin, Australia, in which fine-scale observations of several prescribed fires were made using infrared digital video. Infrared imaging is used routinely to locate fires as infrared radiation suffers little attenuation as it propagates through the smoke that normally obscures visible imagery. However, until now, little use has been made of digital video imagery in analyzing the convective-scale structure of prescribed (or wild) fires. The advantage of digital video imagery is that the individual frames can be objectively analyzed to determine the convective motion in the plane viewed by the camera. The infrared imagery shows mostly rising plumes, much like convective clouds. The flow is highly convective, and the vertical transport of heat is confined to relatively narrow thermals. The updrafts range from a few m?s-1 to around 15?m?s-1. A numerical model is used to simulate one of the prescribed fires at very high-resolution. For the most part, the model predictions compare well to the observations. The model produces plumes that are around 7?m high, and spaced around 5?m apart, which is similar to that observed. The model correctly predicts the mean rate of spread of the fire to be 1.3?m?s-1. Perhaps the most serious limitations to using infrared observations of the type presented here are the difficulties in interpreting precisely the relationship between the observed infrared temperature field and the air temperature calculated by the model, and the exact connection between the infrared camera derived flow field and that calculated by the model. [ABSTRACT FROM AUTHOR]

In an effort to investigate both large-scale (spatial) and short/long-term (temporal) distribution characteristics of atmospheric mercury, we have combined and analyzed the Hg concentration data sets collected continuously by four different scientific groups for the areas and periods covering (1) America (three sites near the Canadian Great Lakes (CGL): 1997-2000), (2) Asia (Seoul, Korea (SEL): 1997-2002), (3) Arctic (Alert, Canada (ALT): 1995-2001), and (4) Europe (Mace Head, Ireland (MH): 1996-2002). The mean concentrations of Hg data from those widely dispersed monitoring stations were computed to be (1) 1.58 ± 0.23, 1.69 ± 0.32, and 1.93 ± 0.44 (three sites in CGL), (2) 5.06 ± 2.46 ng m-3 (SEL), (3) 1.55 ± 0.41 (ALT), and (4) 1.76 ± 0.31 (MH). Intersite relationships were investigated among all different stations using the data groups divided into different temporal intervals. The analysis of diurnal variation patterns of Hg indicated differences in regional source/sink characteristics, with increasing amplitudes of variability toward areas under the strong influence of anthropogenic sources. When the analysis was made over different seasons, the patterns contrasted greatly between the Arctic and the other areas. It was found that the relative enhancement of Hg concentrations was dominant during winter/spring in most areas due to direct or indirect influences of anthropogenic emissions. However, the pattern for the Arctic area was distinguished pronouncedly from others with the spring minimum and summer maximum both of which reflect the potent effects of mercury depletion phenomenon (MDP). By contrast, no long-term trend, either being an increase or decrease, was evident from any of the stations during each respective study period. Although our initial attempts to examine the distribution characteristics of Hg analyzed by different scientific groups were successful, we feel that these efforts should be continued further to extend the compatibility of the global database of Hg. [ABSTRACT FROM AUTHOR]

We propose a simple theoretical radiation scheme for regular building arrays. The essential difference of the present radiation scheme from the previous ones is the explicit consideration of the three-dimensional features of the surface geometry. The model is assumed to be an infinitely extended regular array of uniform buildings, each building composed of six faces (roof, floor, and four vertical walls). Without using time-consuming iterations or statistical approaches, we calculated the view factors of the faces, the complicated sunlit--shadow distributions, and the resulting canopy albedo for any time and location. The model was evaluated by comparing to outdoor experiments in a wide range of seasons and surface geometries. The simulated canopy albedos agreed well with measured values, and the accuracy is a significant improvement over two-dimensional-based model outputs. [ABSTRACT FROM AUTHOR]

The western and central United States experience a pronounced diurnal cycle in rainfall during the warm season. Over the higher terrain west of 105°W, most precipitation occurs in the afternoon, whereas the central United States experiences more nocturnal events. This coherent phase transition between the Rocky Mountains and the U.S. Great Plains is well defined for all warm seasons between 1996 and 2003, provided that the rainfall observations are remapped relative to the elevated terrain in the western United States prior to north–south averaging. Due to the westward shift of the Continental Divide north of 42°N and its intersection with the warm season storm track for 2002, the diurnal coherence greatly improves after remapping the 2002 rainfall observations. This speaks to the long-range influence of orography on precipitation frequency and suggests that the primary east–west corridor of precipitation for an individual warm season intersects the cordillera over a fairly narrow latitude range. [ABSTRACT FROM AUTHOR]

Explores the subjective perception of megalithic people on the cycle of the seasons based on the spring full moon. Regularities involved in the rising of the spring moon; Reference direction for the observation of the full moon rise; Role of spring moon in determining megalithic tombs.

Viking/MAWD experiment and more recent MGC/TES observations have provided to date the most detailed information about the annual atmospheric water cycle on Mars. Their data agree in major details but still reveal some disagreements. These disagreements turn out to be most significant in the perihelion season and especially during the major dust storms. We consider the potential influence of aerosol scattering on 1.38 μm water retrieval under various types of observation geometry. In order to obtain new retrievals of water vapor abundance from MAWD data, we apply radiative transfer calculations. The resulting seasonal and spatial distribution of water turns out to be more consistent with TES results, implying a remarkable stability of the martian seasonal water cycle. Mapping data corresponding to particular seasons reveals a distinct wave structure in the global distribution of the water column. We interpret it as a manifestation of a strong control over the water cycle on Mars from the atmospheric circulation. [Copyright &y& Elsevier]

It is suggested that the seasonal dependence of interannual variability displayed by observed sea surface temperature (SST) over the north tropical Atlantic primarily reflects the seasonality of the remote forcing associated with the North Atlantic and Southern Oscillations and is controlled by the mean damping time scale of SST anomaly. A stochastic model including a seasonally dependent forcing is used to test this hypothesis against observations. [ABSTRACT FROM AUTHOR]

The electric and magnetic field structures around a semi-infinite thin-wire antenna vertically placed above a perfectly conducting ground plane are investigated when the antenna is supporting two different types of sources. It is shown that when the wire is carrying a uniform line charge, the electrostatic potentials are equal on the surfaces of imaginary cones of fixed cone angles with axis along the wire and apex at the conducting plane. The electrostatic field vectors are shown to be perpendicular to the imaginary cones and tangential to the meridian lines of half-spherical shells centered at the base of the line charge. The vertical components of the electrostatic field on the surface of these imaginary half-spherical shells of a given radius are constant, except at the wire itself. The magnetic field structure associated with a constant current in the semi-infinite antenna is that of an infinite wire. The electric and magnetic fields due to a time-varying charge or current pulse propagating with the speed of light along the vertical thin-wire antenna have a spherical transverse electromagnetic (TEM) field structure, identical to that for the case of a uniform line charge and a uniform current. The connection between the static and dynamic solutions is derived mathematically using two different approaches. [Copyright &y& Elsevier]

It is well known that air pollution is one of the major factors affecting human health and the activities in a town. Among the various air pollutants an interesting one, especially for sunny climates, is the reactive O3. O3 varies significantly through the year; it is therefore very important to know the onset and the duration of the warm period of the year since at that time O3 concentrations increase significantly. In this work, an attempt was made to determine the onset of warm season of the year as well as its duration in various sites located in Northeastern Mediterranean. For this purpose, a fuzzy clustering method is used. The method was applied on the isobaric thickness between 1000 and 500 hPa for the period from 1974 to 1997. The results were compared to conventional methods based on synoptic classification and were found to be in good agreement. [ABSTRACT FROM AUTHOR]

The natural variability over the North Pacific, where the influence of tropical El Niño—Southern Oscillation (ENSO) events is substantial, is examined to determine whether there is a large change owing to a difference in the ENSO forcing anomaly. The hindcast ensemble runs of the Seasonal Forecast Model of the National Centers for Environmental Prediction are analyzed for this assessment. Four sets of 10-member ensemble hind-casts out to 7 months with T42 horizontal resolution and another four sets with T62 resolution are examined in detail. The results consistently indicate that the natural variability, on both seasonal and monthly time scales, is significantly smaller during El Niño boreal winters than during La Niña boreal winters. The implication is that the predictability on both seasonal and monthly time scales over the North Pacific is potentially higher during El Niño winters than during La Niña winters. [ABSTRACT FROM AUTHOR]

We describe the eosimiid primate fossils collected during the course of four field seasons in the late middle Eocene Heti Formation of central China. In addition to providing new information about the anatomy of Eosimias centennicus, the Heti Formation sample documents substantial taxonomic diversity in the Asian eosimiid radiation. One new genus and three new species of Eosimiidae are proposed here. These include Eosimias dawsonae, n. sp.; Phenacopithecus xueshii, n. gen. and sp.; and Phenacopithecus krishtalkai, n. sp.The anatomy of the upper dentition of eosimiids is described in detail for the first time. As is the case for the lower dentition, a unique combination of primitive and derived traits characterizes the upper dentition of Eosimias and Phenacopithecus. Eosimiid upper molars bear many of the same derived features—including strong protocone cristae and the absence of a postprotocingulum—that have been cited as evidence for a special relationship between anthropoids and certain adapiforms. However, the upper molars of eosimiids further approximate those of other basal anthropoids in having reduced or absent conules and complete lingual cingula. These features are lacking in Periconodon and other adapiforms that have been regarded by some workers as being phylogenetically close to anthropoids. Given that similarities in upper molar anatomy are among the only derived features that can be cited in support of a possible adapiform ancestry for anthropoids, the occurrence of these same features in eosimiids significantly weakens the adapiform hypothesis of anthropoid origins.The holotype maxillary fragment of Phenacopithecus krishtalkai reveals that eosimiids possessed a relatively small infraorbital foramen and a deep lower face between the inferior orbital margin and the alveolar border. Eosimiids therefore lacked the orbital hypertrophy characteristic of living tarsiers and many fossil omomyids and microchoerids. Eosimiids apparently had relatively small orbits, suggesting that they maintained a diurnal activity cycle. [Copyright &y& Elsevier]

In this paper, the relationship between seasonal mean (June, July, August and September) monsoon circulation features and the midlatitude circulations in winter and spring seasons have been examined during contrasting years of more (less) number of snow days in winter/spring followed by deficient (excess) Indian Summer Monsoon Rainfall (ISMR) using NCEP/NCAR reanalyzed data for the period 1966-1994. The Historical Soviet Daily Snow Depth (HSDSD) version II data set has been used to calculate the number of days of snow over west and east Eurasia separately under three classes: class 1 for SD > 5 cm, class 2 for SD > 10cm and class 3 for SD > 50 cm where SD stands for snow depth. Correlation coefficients are computed between the anomaly in the number of days of snow depth under the above three classes during winter/spring over west and east Eurasia and the subsequent ISMR. HSDSD data show that difference in the number of days of SD > 10 cm in two extreme years is most prominent in the west Eurasia in the months of January and April. Also the anomaly in the number of days of snow in January and April over west Eurasia has correlation coefficients of -0.69 and -0.56 with the following ISMR, respectively at 0.1% significance level when the SD is more than 10 cm at all the stations. Results also show that low-level atmospheric temperature difference between two extreme years of snow days in winter is up to 10°C and the cooling persists up to spring season with a difference of 2 °C. This cooling persistence may give rise to anomalous cyclonic circulations over the midlatitudes and tropics which may be responsible for weakening the monsoon circulation over India during the year of more snow days over west Eurasia. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effects of the waste-rock dump (WRD) of the underground polymetallic Balya Mine on the Kocacay River and eventually on Lake Manyas in Turkey. Data presented in this paper include geochemical characteristics of various kinds of water (mine, surface and groundwater) and of suspended-particle samples in the vicinity of Balya. The more polluted mine waters have low pH and high conductivity, while high concentrations of Zn, Cd, Mn tend to be found in the dry and wet seasons. High concentrations of Pb, As, Cr, Cu and S appear only in the wet season. The sources of the heavy metal concentration within the Kocacay River are leached waste, surface run off, and overflow from the spillway of the WRD. To minimize the formation of acids and dissolved metal, and for the remediation of the harmful effects of extreme contamination conditions, it is recommended that lime or alkali materials and organic carbon be added to simulate the action of sulfate-reducing bacteria. [ABSTRACT FROM AUTHOR]

An analysis is presented of 46 ice break up and 15 ice free season phenology data series obtained largely through volunteer monitoring efforts in Southern Ontario. Observations spanned the years 1853–2001. Available data included dates of ice formation and ice break up as well as the number of ice free days in a year. A high degree of temporal coherence in ice phenology between lakes was observed (137/365 pairwise correlations significant at P<0.05). Significant monotonic trends towards earlier break up dates and longer ice free seasons were observed across the region both in the entire series and in the last thirty years of data. Trends in longer series may be associated with the end of the Little Ice Age. The significantly longer ice free seasons and earlier ice break up dates observed in the study area have important implications for lakes in other parts of Canada where climate change effects are predicted to be more extreme than in South-Central Ontario. [ABSTRACT FROM AUTHOR]

In this paper we carry out a correlative analysis of the measurements of the photospheric magnetic field Bd (the magnetic component along the line of sight) from NSO/KP, and of the calculations of the field components on the visible solar disk from these measurements using Rudenko's (2001) potential field approximation method. The analysis revealed the following features: (1) near the equator the character of variation of langle|Bd| rangle(ρ) varies with the range of the values of |Bd| used in the analysis (here the brackets langle rangle denote an averaging over time and over the area of the portion of the size 10°×10°, and ρ is the angle between this portion and the central meridian (CM)); (2) generally near the equator there is a relatively small field `radiality': the value of langle|BR| rangle/ langle|BF| rangle near the CM varies over the range 1.25–0.9 and increases from the CM to the limb (here BR and BF are the calculated radial and toroidal field components); (3) the magnetic field measurements near the equator are different for different longitudes; (4) in the region of coronal holes (He i λ10 830 Å) and at the calculated bases of open magnetic tubes (OMT) there is an increased `radiality' of the magnetic field in comparison with solar disk areas near the equator. The largest recorded values of the ratios of area-averaged coronal holes (CH) and OMT of the moduli of the radial and transverse field components were 9.2 in CH, and 4 in OMT. [ABSTRACT FROM AUTHOR]

During winter season, atmospheric systems, which traverse from west to east interact with the Himalayan massif and produce widespread rainfall over North India. In this study, we made an endeavor to examine the mean circulation features and large-scale budgets of kinetic energy, heat and moisture over Himalayas and the adjoining domain for winter season. The time-mean circulation is bifurcated into stable mean and transient eddy parts and examined the mean component of the circulation. The uninitialized daily analyses of European Centre for Medium range Weather Forecasts (ECMWF) for five winter seasons (1986-90) comprising December, January and February (DJF) have been used for the purpose. We noticed certain zones of strong activity over Iran, Afghanistan, and West China regions during winter season. These are characterized by intense vertical motions, cyclonic vorticity and adiabatic generation of kinetic energy. The features noticed over these zones include strong horizontal convergence of heat and moisture. These zones are further characterized by massive adiabatic conversion of available potential energy to kinetic energy. These features are conducive for the growth of atmospheric systems, which traverse over the zones and produce precipitation subsequently. [ABSTRACT FROM AUTHOR]

The influence of eel odour on the efficiency of a freshwater eel ladder and trap was assessed during two glass eel and yellow eel springtime upstream migration seasons in the Vilaine estuary, France. This test consisted of alternatively directing the outflow from the trap holding bin, away from, or onto the trap access ladder and comparing catches. Catches were 1.4 higher for both glass eels and juvenile eels when the trap water was directed towards the pass. The experiment had little influence on predicting ladder catches when compared to the environmental parameters. The distance of detection of the scent was calculated to range between 0 and 5 m from the ladder. [ABSTRACT FROM AUTHOR]

Summary¶Daily global and diffuse radiation measurements have been used to characterize the atmosphere optical conditions at Kwangju (Lat.35.13N, Long.126.53E) and Seoul (Lat.37.57N, Long.126.98E) in South Korea and Ile-Ife (Lat.7.14N, Long.4.56E) in Nigeria. The clearness index, (CI) which gives the percentage depletion by the sky of the incoming global radiation and the diffuse ratio, (DR) which represents the effectiveness of the sky in scattering incoming radiation have been analyzed in this study. Results show an average clearness index value of 0.57 for the year 1999 with maximum values occurring during the wet seasons at Ile-Ife. The average clearness indexes for Kwangju and Seoul from 1998–2000 was 0.48 and 0.34, respectively, with both stations having maximum clearness indexes in the winter seasons. The diffuse ratio was higher at Kwangju and Seoul than at Ile-Ife due to heavy dust pollution from the Gobi desert in the Korea peninsula in spring, and high biomass burning at Kwangju in the fall. [ABSTRACT FROM AUTHOR]

Earlier GCM studies have expressed the concern that an enhancement of greenhouse warming might increase the occurrence of summer droughts in mid-latitudes, especially in southern Europe and central North America. This could represent a severe threat for agriculture in the regions concerned, where summer is the main growing season. These predictions must however be considered as uncertain, since most studies featuring enhanced summer dryness in mid-latitudes use very simple representations of the land-surface processes (''bucket'' models), despite their key importance for the issue considered. The current study uses a regional climate model including a land-surface scheme of intermediate complexity to investigate the sensitivity of the summer climate to enhanced greenhouse warming over the American Midwest. A surrogate climate change scenario is used for the simulation of a warmer climate. The control runs are driven at the lateral boundaries and the sea surface by reanalysis data and observations, respectively. The warmer climate experiments are forced by a modified set of initial and lateral boundary conditions. The modifications consist of a uniform 3 K temperature increase and an attendant increase of specific humidity (unchanged relative humidity). This strategy maintains a similar dynamical forcing in the warmer climate experiments, thus allowing to investigate thermodynamical impacts of climate change in comparative isolation. The atmospheric CO2 concentration of the sensitivity experiments is set to four times its pre-industrial value. The simulations are conducted from March 15 to October 1st, for 4 years corresponding to drought (1988), normal (1986, 1990) and flood (1993) conditions. The numerical experiments do not present any great enhancement of summer drying under warmer climatic conditions. First, the overall changes in the hydrological cycle (especially evapotranspiration) are of small magnitude despite the strong forcing applied. Second, precipitation increases in spring lead to higher soil water recharge during this season, compensating for the enhanced soil moisture depletion occurring later in the year. Additional simulations replacing the plant control on transpiration with a bucket-type formulation presented increased soil drying in 1988, the drought year. This suggests that vegetation control on transpiration might play an important part in counteracting an enhancement of summer drying when soil water gets limited. Though further aspects of this issue would need investigating, our results underline the importance of land-surface processes in climate integrations and suggest that the risk of enhanced summer dryness in the region studied might be less acute than previously assumed, provided the North American general circulation does not change markedly with global warming. [ABSTRACT FROM AUTHOR]

Riverine water samples were collected from the lower reach hydrometric station Makou of the Xijiang River, in four hydrological seasons during 1997 and 1998. The samples were analyzed for their particulate and dissolved organic carbon. The contents of riverine particulate and dissolved organic carbon changed synchronously during different hydrological processes. The contents of organic carbon and total suspended substances in the riverine water increased with increasing discharge. The mass of organic carbon in the total suspended substances decreased logarithmically with increasing total suspended substances. The transported flux of organic carbon in the Xijiang River drainage is about 10.18×106 g of C km–2 year–1, which is two to three times larger than that of the average value in other river systems. Particulate organic carbon is the main component of riverine organic carbon, with a flux of about 8.30×106 g of C km–2 year–1. [ABSTRACT FROM AUTHOR]

1.The rich zooplankton, fish and squid resources on the Patagonian Shelf sustain substantial populations of largely resident seabirds and marine mammals. These habitats are also visited seasonally by similar species from elsewhere but few data exist on their status and origin. Recent studies, using satellite-tracking to determine foraging ranges and feeding areas of seabirds and marine mammals breeding at South Georgia, have shown that several species make substantial use of the waters of the Patagonian Shelf. 2.Wandering albatrosses use shelf-edge areas year-round with direct observations of both sexes of almost all age classes, including, breeding, pre-breeding and non-breeding individuals. White-chinned petrels and female Northern and Southern giant petrels mainly visit during incubation and post-breeding, particularly to the Falklands Current (White-chinned petrels) and to upwelling areas around the southern shelf-break from the Burdwood Bank in the east to Staten Island and Diego Ramirez in the west (giant petrels). Northern giant petrel males during incubation and Antarctic fur seals in winter reach inner shelf habitats in the northern sector. In contrast, South Georgia populations of black-browed and grey-headed albatrosses do not appear to use the Patagonian Shelf at any stage of their breeding cycle. 3.Although the use of the Patagonian Shelf by visiting species is now best documented for South Georgia species, recent observational data confirm that seabirds from Diego Ramirez, Tristan da Cunha and Gough visit the southern and northern sectors, during both breeding and non-breeding seasons respectively. Several Antarctic species (notably Antarctic fulmar and cape petrel) winter in the region as do at least two albatross species from New Zealand; other species (especially Wilson''s storm petrels) use it as a staging ground on migration, as do several species of baleen whales and possibly other cetacean species. 4.Three of the seabird species which breed on the Patagonian Shelf are Globally Threatened; seven of the visiting species (and four baleen whale species) also have this status. The Patagonian Shelf is, therefore, not only of global importance for the diversity and abundance of its resident top predators but is just as critical for the survival of many visiting species, some of which are even more endangered. 5.Combining data from satellite-tracking with conventional mapping from direct observations offers the prospect of defining the foraging ranges (and the main feeding areas within these) of a range of key top predator species. Such data should be used, in conjunction with similar information of the distributions of fish, squid and zooplankton resources and of fishing effort, to identify critical marine habitats whose precautionary, multiple-use sustainable management will be vital to protect the interests of both commercial fishers and top predators. Copyright © 2002 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This article presents information regarding the television program "Kommissar Rex." The investigation of crime forms the basis of one of the world's most enduring genres of popular culture, starting with the detective stories of the nineteenth century and moving on to film and television. Many reasons for the popularity of the genre have been put forward. One of these is that crime fiction provides an illustration of sin and guilt with the detective and the criminal acting as the "spirits of light and darkness. Dealing with issues of good and evil and the punishment of crime means that the genre can function as an entertaining moral lesson for adults and children alike. "Kommissar Rex's" success at the top of the television ratings is proof that a combination of crime fiction and a moral lesson can be entertaining as well as a commercial winner. Up until now his fans have switched on in large numbers whenever he went on a case. Yet on Thursday he was lagging behind. A study of viewing figures for recent seasons reveals a downward movement from the 1998 season to the 1999 season.

Weak gravitational lensing surveys have the potential to probe mass density fluctuation in the Universe directly. Recent studies have shown that it is possible to model the statistics of the convergence field at small angular scales by modelling the statistics of the underlying density field in the highly non-linear regime. We propose a new method to model the complete probability distribution function of the convergence field as a function of smoothing angle and source redshift. The model relies on a hierarchical ansatz for the behaviour of higher order correlations of the density field. We compare our results with ray-tracing simulations and find very good agreement over a range of smoothing angles. Whereas the density probability distribution function is not sensitive to the cosmological model, the probability distribution function for the convergence can be used to constrain both the power spectrum and cosmological parameters. [ABSTRACT FROM AUTHOR]

Temperatures in 22 grid boxes across the Mediterranean were subjected to principal component analysis (PCA). Four factors were retained, dividing the Mediterranean into four different subregions in each season (only three in spring). PC1 and PC2 defined the eastern and western Mediterranean, respectively, in all seasons. PC3 defined the central Mediterranean in summer and autumn, the Balkans in winter and a combination of both regions in spring. Finally, PC4 defined the Balkans in summer and autumn and the central Mediterranean in winter. Time series analysis of PC scores enabled the determination of discontinuity time points when abrupt temperature changes occurred. The pressure patterns associated with high temperatures in each region were defined over a major part of the northern hemisphere. The circulation associated with each factor in each season was determined from meridional (MI) and zonal (ZI) circulation indices. A seesaw-like oscillation, namely the Mediterranean Oscillation, was found between the eastern and western Mediterranean. Favourable circulation for high temperatures in one part of the Mediterranean is associated with unfavourable circulation in the other part and vice versa. Copyright © 1999 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Statistical prediction of July–August Central England Temperature (CET) using January–February sea surface temperature anomalies (SSTA) in the North Atlantic was described by Colman (1997), Int. J. Climatol., 17, 1285–1300. In this paper, the method is extended to examine the predictability of rainfall, surface temperature and pressure in Europe. Using a January–February North Atlantic SSTA pattern as predictor, it is found that mean, minimum and maximum July–August temperatures over much of northwest Europe are predictable using linear regression with correlation skills in the range 0.4–0.7, while July–August rainfall and surface pressures are less predictable, with correlation up to 0.4. July–August temperatures in southeast Canada and the northeast USA are also predictable, with correlation up to 0.3. The predictability of other seasons and timescales is also investigated. For UK temperature, half-month to 2-monthly ranges were considered; predictive correlation skills are best for the period from mid July to the end of August. The highest correlations are from predictions of August temperature in eastern France, where correlation over 50 years exceeds 0.7. For other seasons, long-lead predictability from North Atlantic SSTA was found to be much less than for the summer season. Analysis of composite cases shows an association of predictable warm summers with movement of anomalously warm SSTA across the North Atlantic from the East Coast of the USA to the northwest European coast during spring months. Predictability of cold summers seems to be related to persistence of anomalously cold sea surface temperatures (SST) near, or to the east of, the UK throughout spring. Coherence between the winter SST and the summer temperatures is strongest at 7–8 years. Other studies have revealed North Atlantic ocean variability at this timescale. Copyright © 1999 Controller, Her Majesty's Stationery Office, Norwich, England [ABSTRACT FROM AUTHOR]

Isolates of Phytophthora infestans were collected from all potato growing regions of Poland during the blight seasons of 1987-1989. All 1987 isolates were of Al mating type and were sensitive to metalaxyl. In 1988 and 1989, 46.5% and 55.3% of the isolates were sensitive to metalaxyl, respectively. The percentage of highly resistant (R) isolates increased from 25.6% in 1988 to 39.5 % in 1989; however the percentage of intermediately resistant (J) isolates decreased during that period from 27.9% to 5.3 %. A significant association was observed between the Al compatibility type and metalaxyl resistance. The A2 mating type first appeared in 1988, and its frequency increased from 4.7 % of the population in 1988 to 47.6% in 1989. Coincident with this change in mating type frequency, changes in ploidy levels of isolates were observed. Whereas 3% of the 1988 isolates were diploid, 90% of the 1989 A2 isolates and 28.6% of the 1989 A1 isolates were diploid. The approximate 1:1 ratio of the two mating types encountered in 1989, and the predominance of diploidy, indicates that the Polish population of P. infestans has the potential to become sexual. [ABSTRACT FROM AUTHOR]

Presents research which concluded that only half of the seasonal and year-to-year changes in sea level are attributable to thermal expansion. Measurements used for data; Complicated interpretations of data; Annual and interannual cycle of heat flux; Requirement of a large seasonal cycle in the advective heat flux.