Showing papers in "International Journal of Biometeorology in 2007"
TL;DR: The physical basis of the RayMan model, which simulates the short- and long-wave radiation flux densities from the three-dimensional surroundings in simple and complex environments, is presented.
Abstract: Short- and long-wave radiation flux densities absorbed by people have a significant influence on their energy balance. The heat effect of the absorbed radiation flux densities is parameterised by the mean radiant temperature. This paper presents the physical basis of the RayMan model, which simulates the short- and long-wave radiation flux densities from the three-dimensional surroundings in simple and complex environments. RayMan has the character of a freely available radiation and human-bioclimate model. The aim of the RayMan model is to calculate radiation flux densities, sunshine duration, shadow spaces and thermo-physiologically relevant assessment indices using only a limited number of meteorological and other input data. A comparison between measured and simulated values for global radiation and mean radiant temperature shows that the simulated data closely resemble measured data.
1,334 citations
TL;DR: A survey of residents in the metropolitan areas of these cities that gauged their perception of their own vulnerability to the heat, as well as their knowledge of heat warnings and the activities recommended to be undertaken to help mitigate the effects of the heat.
Abstract: To examine the efficacy of municipal heat watch warning systems, a thorough evaluation of the heat mitigation plans of four North American cities - Dayton (Ohio, USA), Philadelphia (Pennsylvania, USA), Phoenix (Arizona, USA), and Toronto (Ontario, Canada) - was undertaken. In concert with this evaluation was a survey of residents in the metropolitan areas of these cities that gauged their perception of their own vulnerability to the heat, as well as their knowledge of heat warnings and the activities recommended to be undertaken to help mitigate the effects of the heat. In total, 908 respondents participated in the telephone survey. Some of the key results indicate that knowledge of the heat warning was nearly universal (90%), and likely due to pervasive media coverage more than any other means. Though knowledge of the event was widespread, knowledge of what to do was less common. Only around half of all respondents mentioned that they changed their behavior, and despite the diversity of information available on mitigating heat vulnerability, most respondents stated that they merely “avoided the outdoors” at all costs. Though air conditioning was nearly ubiquitous among respondents, over a third mentioned that economic factors of energy costs were considered in terms of how long or whether the air conditioner was turned on.
244 citations
TL;DR: The most important element of proactive environmental management to reduce risk is preparation: be informed, develop a strategic plan, observe and recognize animals in distress, and take appropriate tactical action.
Abstract: The adaptive capabilities of animals and livestock production systems have been emphasized in this report. Biometeorology has a key role in rational management to meet the challenges of thermal environments. While the focus is primarily on cattle in warm or hot climates, the importance of dynamic animal responses to environmental challenges applies to all species and climates. Methods used to mitigate environmental challenges focus on heat loss/heat production balance. Under cold stress, reduction of heat loss is the key. Under heat stress, reduction of heat load or increasing heat loss are the primary management tools, although heat-tolerant animals are also available. In general, livestock with health problems and the most productive animals (e.g., highest growth rate or milk production) are at greatest risk of heat stress, thereby requiring the most attention. Risk management, by considering perceived thermal challenges, then assessing the potential consequences and acting accordingly, will reduce the impact of such challenges. Appropriate actions include: shade, sprinkling, air movement, or active cooling. Summarizing, the most important element of proactive environmental management to reduce risk is preparation: be informed, develop a strategic plan, observe and recognize animals in distress, and take appropriate tactical action.
210 citations
TL;DR: A multispecies index from ground-observed spring phases with two types (maximum slope and threshold approach) of satellite-derived start-of-season (SOS) metrics is compared and it is suggested that this snow cover should be better accounted for by the use of newer satellite sensors.
Abstract: Long time series of ground-based plant phenology, as well as more than two decades of satellite-derived phenological metrics, are currently available to assess the impacts of climate variability and trends on terrestrial vegetation. Traditional plant phenology provides very accurate information on individual plant species, but with limited spatial coverage. Satellite phenology allows monitoring of terrestrial vegetation on a global scale and provides an integrative view at the landscape level. Linking the strengths of both methodologies has high potential value for climate impact studies. We compared a multispecies index from ground-observed spring phases with two types (maximum slope and threshold approach) of satellite-derived start-of-season (SOS) metrics. We focus on Switzerland from 1982 to 2001 and show that temporal and spatial variability of the multispecies index correspond well with the satellite-derived metrics. All phenological metrics correlate with temperature anomalies as expected. The slope approach proved to deviate strongly from the temporal development of the ground observations as well as from the threshold-defined SOS satellite measure. The slope spring indicator is considered to indicate a different stage in vegetation development and is therefore less suited as a SOS parameter for comparative studies in relation to ground-observed phenology. Satellite-derived metrics are, however, very susceptible to snow cover, and it is suggested that this snow cover should be better accounted for by the use of newer satellite sensors.
204 citations
TL;DR: The experiment proved that this methodology designed to analyse the relationship between climatic conditions and the perception of bioclimatic comfort is well-suited to achieving the proposed objectives and that it may be applied in other areas and in other seasons.
Abstract: This paper describes the application of a methodology designed to analyse the relationship between climatic conditions and the perception of bioclimatic comfort. The experiment consisted of conducting simultaneous questionnaire surveys and weather measurements during 2 sunny spring days in an open urban area in Lisbon. The results showed that under outdoor conditions, thermal comfort can be maintained with temperatures well above the standard values defined for indoor conditions. There seems to be a spontaneous adaptation in terms of clothing whenever the physiological equivalent temperature threshold of 31°C is surpassed. The perception of air temperature is difficult to separate from the perception of the thermal environment and is modified by other parameters, particularly wind. The perception of solar radiation is related to the intensity of fluxes from various directions (i.e. falling upon both vertical and horizontal surfaces), weighted by the coefficients of incidence upon the human body. Wind was found to be the most intensely perceived variable, usually negatively. Wind perception depends largely on the extreme values of wind speed and wind variability. Women showed a stronger negative reaction to high wind speed than men. The experiment proved that this methodology is well-suited to achieving the proposed objectives and that it may be applied in other areas and in other seasons.
183 citations
TL;DR: There is a strong sense of perceived risk to the heat among Hispanics which translates to increased response when heat warnings are issued, and suggestions are presented to help improve the Phoenix Heat Warning System.
Abstract: Heat is the leading weather-related killer in the United States. Although previous research suggests that social influences affect human responses to natural disaster warnings, no studies have examined the social impacts of heat or heat warnings on a population. Here, 201 surveys were distributed in Metropolitan Phoenix to determine the social impacts of the heat warning system, or more specifically, to gauge risk perception and warning response. Consistent with previous research, increased risk perception of heat results in increased response to a warning. Different social factors such as sex, race, age, and income all play an important role in determining whether or not people will respond to a warning. In particular, there is a strong sense of perceived risk to the heat among Hispanics which translates to increased response when heat warnings are issued. Based on these findings, suggestions are presented to help improve the Phoenix Heat Warning System.
182 citations
TL;DR: Analysis of individual ‘heat waves’ illustrates that a greater proportion of mortality is due to mortality displacement in cities with less sensitive temperature–mortality relationships than in those with more sensitive relationships, and that mortality displacement is no longer a feature more than 12 days after the end of the heat wave.
Abstract: Heat waves are expected to increase in frequency and magnitude with climate change. The first part of a study to produce projections of the effect of future climate change on heat-related mortality is presented. Separate city-specific empirical statistical models that quantify significant relationships between summer daily maximum temperature (T
max) and daily heat-related deaths are constructed from historical data for six cities: Boston, Budapest, Dallas, Lisbon, London, and Sydney. ‘Threshold temperatures’ above which heat-related deaths begin to occur are identified. The results demonstrate significantly lower thresholds in ‘cooler’ cities exhibiting lower mean summer temperatures than in ‘warmer’ cities exhibiting higher mean summer temperatures. Analysis of individual ‘heat waves’ illustrates that a greater proportion of mortality is due to mortality displacement in cities with less sensitive temperature–mortality relationships than in those with more sensitive relationships, and that mortality displacement is no longer a feature more than 12 days after the end of the heat wave. Validation techniques through residual and correlation analyses of modelled and observed values and comparisons with other studies indicate that the observed temperature–mortality relationships are represented well by each of the models. The models can therefore be used with confidence to examine future heat-related deaths under various climate change scenarios for the respective cities (presented in Part 2).
139 citations
TL;DR: Workers' preferences for air movement have been extracted from a database of indoor environmental quality surveys performed in over 200 buildings as discussed by the authors, and the results raise questions about the consequences of the ASHRAE and ISO standards' restrictions on air movement.
Abstract: Office workers’ preferences for air movement have been extracted from a database of indoor environmental quality surveys performed in over 200 buildings. Dissatisfaction with the amount of air motion is very common, with too little air movement cited far more commonly than too much air movement. Workers were also surveyed in a detailed two-season study of a single naturally ventilated building. About one-half the building’s population wanted more air movement and only 4% wanted less. This same ratio applied when the air movement in workspaces was higher than 0.2 m/s, the de facto draft limit in the current ASHRAE and ISO thermal environment standards. Preference for “less air motion” exceeded that for “more” only at thermal sensations of −2 (cool) or colder. These results raise questions about the consequences of the ASHRAE and ISO standards’ restrictions on air movement, especially for neutral and warm conditions.
121 citations
TL;DR: To map the annual and spatial variability of the start of the growing season (SOS) in Fennoscandia, the twice-monthly GIMMS-NDVI satellite dataset was used and showed that 1985 was the most extreme year in terms of late SOS.
Abstract: Fennoscandia is characterized by a large degree of climatic diversity. Vegetation phenology may respond differently to climate change according to the climatic gradients within the region. To map the annual and spatial variability of the start of the growing season (SOS) in Fennoscandia, the twice-monthly GIMMS-NDVI satellite dataset was used. The data set has an 8 × 8 km2 spatial resolution and covers the period from 1982 to 2002. The mapping was done by applying pixel-specific threshold values to the NDVI data. These threshold values were determined form surface phenology data on birch (Betula sp.). Then, we produced NDVI based maps of SOS for each of the 21 years. Finally, the time differences between the SOS and the last day of snow cover, as well as dates of passing different temperatures, were analyzed for 21 meteorological stations. The analyses showed that 1985 was the most extreme year in terms of late SOS. In terms of early SOS, the year 1990 was by far the most extreme. Locally, the SOS has an average range of 1 month between the earliest and latest recorded SOS, with a trend towards a bigger range in the oceanic parts. The results indicate that a 1°C increase in spring temperatures in general corresponds to an advancement of 5–6 days in SOS. However, there is a clear trend according to the degree of oceanity, with a 1°C increase in the most oceanic parts corresponding roughly to 7–9 days earlier SOS, compared to less than 5 days earlier in the continental parts.
112 citations
TL;DR: The reduction in plasma ALP activity in the hotter period of both years confirmed the role of this enzyme as a quick and reliable heat-stress blood marker.
Abstract: In two consecutive summers, 21 and 18 cows, respectively, were monitored for blood parameters and milk yield, to assess their variation according to the level of heat stress at different stages of lactation. During both years, the cows were monitored according to their lactation phase (early, mid-, and late) at the beginning of the summer. Climatic conditions were described through the temperature humidity index. Cows were monitored for breathing rate, rectal temperature, blood metabolites and enzymes, and milk yield. In the first year, two hotter periods were identified, with more severe conditions in the second one, when cows had rectal temperatures higher than 40°C. In the second year, only one hotter period was identified, with a heat stress comparable to that of the first period of the first year. Milk yield declined during the hotter period; in both years, a higher reduction in milk yield was recorded for cows in the mid-stage of lactation. The decrease in plasma glucose during the hotter period was evident in both years. Plasma cholesterol also decreased in those periods. The reduction in plasma ALP activity in the hotter period of both years confirmed the role of this enzyme as a quick and reliable heat-stress blood marker.
112 citations
TL;DR: The algorithm generates realistic seasonal patterns, variability and extremes of temperature, precipitation, frost-free periods and hot spells, however, it predicts less accurately the daily probability of precipitation, extreme precipitation events and the duration of extreme droughts.
Abstract: A simple, stochastic daily temperature and precipitation generator (TEMPGEN) was developed to generate inputs for the study of the effects of climate change on models driven by daily weather information when climate data are available as monthly summaries The model uses as input only 11 sets of monthly normal statistics from individual weather stations It needs no calibration, and was parameterized and validated for use in Canada and the continental United States Monthly normals needed are: mean and standard deviation of daily minimum and maximum temperature, first and second order autoregressive terms for daily deviations of minimum and maximum temperatures from their daily means, correlation of deviations of daily minimum and maximum temperatures, total precipitation, and the interannual variance of total precipitation The statistical properties and distributions of daily temperature and precipitation data produced by this generator compared quite favorably with observations from 708 stations throughout North America (north of Mexico) The algorithm generates realistic seasonal patterns, variability and extremes of temperature, precipitation, frost-free periods and hot spells However, it predicts less accurately the daily probability of precipitation, extreme precipitation events and the duration of extreme droughts
TL;DR: Back-trajectory analysis has shown that there is a possibility that long-range transport brings Ambrosia pollen to Poznań from southern Poland, the Czech Republic, Slovakia and Hungary, and there is also a likelihood thatAmbrosia is present in Poland, as shown by the arrival of pollen during the afternoon that originated primarily from within the country.
Abstract: The pollen grains of Ambrosia spp. are considered to be important aeroallergens in parts of southern and central Europe. Back-trajectories have been analysed with the aim of finding the likely sources of Ambrosia pollen grains that arrived at Poznan (Poland). Temporal variations in Ambrosia pollen at Poznan from 1995–2005 were examined in order to identify Ambrosia pollen episodes suitable for further investigation using back-trajectory analysis. The trajectories were calculated using the transport model within the Lagrangian air pollution model, ACDEP (Atmospheric Chemistry and Deposition). Analysis identified two separate populations in Ambrosia pollen episodes, those that peaked in the early morning between 4 a.m. and 8 a.m., and those that peaked in the afternoon between 2 p.m. and 6 p.m.. Six Ambrosia pollen episodes between 2001 and 2005 were examined using back-trajectory analysis. The results showed that Ambrosia pollen episodes that peaked in the early morning usually arrived at Poznan from a southerly direction after passing over southern Poland, the Czech Republic, Slovakia and Hungary, whereas air masses that brought Ambrosia pollen to Poznan during the afternoon arrived from a more easterly direction and predominantly stayed within the borders of Poland. Back-trajectory analysis has shown that there is a possibility that long-range transport brings Ambrosia pollen to Poznan from southern Poland, the Czech Republic, Slovakia and Hungary. There is also a likelihood that Ambrosia is present in Poland, as shown by the arrival of pollen during the afternoon that originated primarily from within the country.
TL;DR: The preponderance of climate correlations is with the early migratory period, not the median of arrival, suggesting that early spring conditions constrain the onset or rate of migration for some species.
Abstract: The intra- and inter-season complexity of bird migration has received limited attention in climatic change research. Our phenological analysis of 22 species collected in Chicago, USA, (1979–2002) evaluates the relationship between multi-scalar climate variables and differences (1) in arrival timing between sexes, (2) in arrival distributions among species, and (3) between spring and fall migration. The early migratory period for earliest arriving species (i.e., short-distance migrants) and earliest arriving individuals of a species (i.e., males) most frequently correlate with climate variables. Compared to long-distance migrant species, four times as many short-distance migrants correlate with spring temperature, while 8 of 11 (73%) of long-distance migrant species’ arrival is correlated with the North Atlantic Oscillation (NAO). While migratory phenology has been correlated with NAO in Europe, we believe that this is the first documentation of a significant association in North America. Geographically proximate conditions apparently influence migratory timing for short-distance migrants while continental-scale climate (e.g., NAO) seemingly influences the phenology of Neotropical migrants. The preponderance of climate correlations is with the early migratory period, not the median of arrival, suggesting that early spring conditions constrain the onset or rate of migration for some species. The seasonal arrival distribution provides considerable information about migratory passage beyond what is apparent from statistical analyses of phenology. A relationship between climate and fall phenology is not detected at this location. Analysis of the within-season complexity of migration, including multiple metrics of arrival, is essential to detect species’ responses to changing climate as well as evaluate the underlying biological mechanisms.
TL;DR: A new approach to characterise geographical areas with a drought risk index (DRI) is suggested, by applying an artificial neural network (ANN) classifier to bioclimatic time series for which operational temporal units (OtUs) are defined.
Abstract: A new approach to characterise geographical areas with a drought risk index (DRI) is suggested, by applying an artificial neural network (ANN) classifier to bioclimatic time series for which operational temporal units (OtUs) are defined. A climatic database, corresponding to a grid of 8 km × 8 km cells covering the Italian peninsula, was considered. Each cell is described by the time series of seven variables recorded from 1989 to 2000. Sixteen cells were selected according to land cover homogeneity and completeness of the time series data. The periodic components of the time series were calculated by means of the fast Fourier transform (FFT) method. Temporal units corresponding to the period of the sinusoidal functions most related to the data were used as OtUs. The ANN for each OtU calculates a DRI value ranging between −1 and 1. The value is interpretable as the proximity of the OtUs to one of two situations corresponding to minimum and maximum drought risk, respectively. The former set (DRI = −1) is represented by an ideal OtU with minimum values of temperatures and evapo-transpiration, and maximum values of rainfall, normalised difference vegetation index (NDVI) and soil water content. The second set (DRI = 1) is represented by the reciprocal OtU to the former one. The classification of the cells based on DRI time profiles showed that, at the scale used in this work, DRI has no dependence on land cover class, but is related to the location of the cells. The methodology was integrated with GIS (geographic information system) software, and used to show the geographic pattern of DRI in a given area at different periods.
TL;DR: The inclusion of individual characteristics in the Fiala model improved the predictions for an individual and led to a significantly smaller systematic error, however, a large part of the discrepancies in individual response to cold remained unexplained.
Abstract: Most computer models of human thermoregulation are population based. Here, we individualised the Fiala model [Fiala et al. (2001) Int J Biometeorol 45:143-159] with respect to anthropometrics, body fat, and metabolic rate. The predictions of the adapted multisegmental thermoregulatory model were compared with measured skin temperatures of individuals. Data from two experiments, in which reclining subjects were suddenly exposed to mild to moderate cold environmental conditions, were used to study the effect on dynamic skin temperature responses. Body fat was measured by the three-compartment method combining underwater weighing and deuterium dilution. Metabolic rate was determined by indirect calorimetry. In experiment 1, the bias (mean difference) between predicted and measured mean skin temperature decreased from 1.8 degrees C to -0.15 degrees C during cold exposure. The standard deviation of the mean difference remained of the same magnitude (from 0.7 degrees C to 0.9 degrees C). In experiment 2 the bias of the skin temperature changed from 2.0+/-1.09 degrees C using the standard model to 1.3+/-0.93 degrees C using individual characteristics in the model. The inclusion of individual characteristics thus improved the predictions for an individual and led to a significantly smaller systematic error. However, a large part of the discrepancies in individual response to cold remained unexplained. Possible further improvements to the model accomplished by inclusion of more subject characteristics (i.e. body fat distribution, body shape) and model refinements on the level of (skin) blood perfusion, and control functions, are discussed.
TL;DR: Finns are well adapted to the cold climate, but the high prevalence of cold-related complaints poses a challenge to the health care system in terms of decreased performance and the possibility that such symptoms predict more serious health effects, such as increased mortality.
Abstract: The prevalence of cold-related complaints and symptoms in the general population has remained unknown. As part of the nationwide FINRISK 2002 health survey performed in Finland, 8,723 people aged 25–64 years filled in a questionnaire asking about the number of hours spent weekly in cold air, their sensations during cold exposure, cold-related complaints, symptoms of diseases, and degradation of performance. Cold thermal sensations at +5°C to −5°C were reported by 35% of men and 46% of women. Almost all subjects reported at least some cold-related complaints, most commonly musculoskeletal pain (men 30%, women 27%), followed by respiratory (25% / 29%), white finger (15% / 18%) and episodic peripheral circulation symptoms (12% / 15%). Decreased mental or physical performance in cold was reported by 75% of men and 70% of women, most commonly impairing manual dexterity and tactile sense. With declining temperature, the first symptom to emerge was pain in the elbow or the forearm (at −3°C), followed by increased excretion of mucus from the lungs (−5°C), while most other symptoms appeared only at lower temperatures of −15°C to −20°C. Most symptoms showed little or no association with the weekly duration of exposure, with the exception of cold-induced pain at most sites. Although, in general, Finns are well adapted to the cold climate, the high prevalence of cold-related complaints poses a challenge to the health care system in terms of decreased performance and the possibility that such symptoms predict more serious health effects, such as increased mortality.
TL;DR: Cavities in healthy trees were warmer than those in dead trees, but this difference disappeared with rising mean ambient temperatures, and the predictors of microclimate may provide indirect cues to prospecting birds.
Abstract: We examined the relationships between cavity temperature, ambient temperature outside the cavity and structural characteristics of 70 cavities measured for 1 night to determine if cavity roosting birds may potentially select warmer tree cavities for wintertime roosting. The mean temperature increment of the cavity (=cavity-ambient temperature) varied from −2.4 to 4.9°C and increased with higher day-to-night fluctuations in the ambient temperature, smaller cavity entrance and better health status of the cavity tree. Cavities in healthy trees were warmer than those in dead trees, but this difference disappeared with rising mean ambient temperatures. This interaction between the effects of tree health status and mean ambient temperature, as well as the effect of day-to-night fluctuations in the ambient temperature, were supported by the analysis of repeated measurements of temperature taken on 12 consecutive nights in five cavities. The variability in cavity microclimates makes the selection of warmer roost sites possible, and the predictors of microclimate may provide indirect cues to prospecting birds.
TL;DR: A cost-benefit analysis of flood control measures and a study of a dam design that would maintain the beneficial aspects of flooding should be accorded the highest priority.
Abstract: The building of a large multipurpose dam is planned at Stiegler’s Gorge on the Rufiji River (Tanzania). Both national and local authorities have strongly emphasised the flood control aspect of the dam as they see the Rufiji floods as a major constraint to development. Though it is true that the Rufiji River has a high flow variability at various timescales, the flood perception in local communities differs from this view. The floods, essential for the sustenance of floodplain fertility, and therefore of the farming system, and vital to the productivity of most of the natural resources on which local communities depend, are perceived as a blessing, whilst droughts and the absence of regular flooding are perceived as the main threat. Historically, most of the food shortages in Rufiji District are associated with drought years and the myth of “the flood as a plague” emerged only in the late 1960s during the Ujamaa villagisation policy. The persistence of this myth is favoured by the inadequate assessment of the complexity of the local economies by the District technical staff. This difference in perception of the flood has major implications for development options. Under the current dam design, the alteration of the flooding pattern would have negative consequences for the downstream wetland and forest ecosystems and the flood-associated livelihoods of some 150,000 people. A cost-benefit analysis of flood control measures and a study of a dam design that would maintain the beneficial aspects of flooding should be accorded the highest priority.
TL;DR: The purpose of this study is to test the relationship between monthly temperature and monthly suicide, independent of months or seasons, for five counties located across the United States and it appears that the seasonality of suicides is due to factors other than temperature.
Abstract: Effects of weather variables on suicide are well-documented, but there is still little consistency among the results of most studies. Nevertheless, most studies show a peak in suicides during the spring season, and this is often attributed to increased temperatures. The purpose of this study is to test the relationship between monthly temperature and monthly suicide, independent of months or seasons, for five counties located across the United States. Harmonic analysis shows that four of the five counties display some seasonal components in the suicide data. However, simple linear regression shows no correlation between suicide and temperature, and discriminant analysis shows that monthly departure from mean annual suicide rates is not a useful tool for identifying months with temperatures that are colder or warmer than the annual average. Therefore, it appears that the seasonality of suicides is due to factors other than temperature.
TL;DR: It is found that the swift and the barn swallow significantly advanced both arrival and laying dates, whereas all other species did not show any significant temporal trend in either arrival or laying date.
Abstract: Climate change is affecting the phenology of seasonal events in Europe and the Northern Hemisphere, as shown by several studies of birds’ timing of migration and reproduction. Here, we analyse the long-term (1982–2006) trends of first arrival dates of four long-distance migratory birds [swift (Apus apus), nightingale (Luscinia megarhynchos), barn swallow (Hirundo rustica), and house martin (Delichon urbicum)] and first egg laying dates of two migrant (swift, barn swallow) and two resident species [starling (Sturnus vulgaris), Italian sparrow (Passer italiae)] at a study site in northern Italy. We also addressed the effects of local weather (temperature and precipitation) and a climate index (the North Atlantic Oscillation, NAO) on the interannual variability of phenological events. We found that the swift and the barn swallow significantly advanced both arrival and laying dates, whereas all other species did not show any significant temporal trend in either arrival or laying date. The earlier arrival of swifts was explained by increasing local temperatures in April, whereas this was not the case for arrival dates of swallows and first egg laying dates of both species. In addition, arrival dates of house martins were earlier following high NAO winters, while nightingale arrival was earlier when local spring rainfall was greater. Finally, Italian sparrow onset of reproduction was anticipated by greater spring rainfall, but delayed by high spring NAO anomalies, and swift’s onset of reproduction was anticipated by abundant rainfall prior to reproduction. There were no significant temporal trends in the interval between onset of laying and arrival in either the swift or the barn swallow. Our findings therefore indicate that birds may show idiosyncratic responses to climate variability at different spatial scales, though some species may be adjusting their calendar to rapidly changing climatic conditions.
TL;DR: The results suggest that the advance in the timing of spring migration is primarily due to the increased frequency of tailwinds favorable for migratory flights over the migratory route, and the earlier emergence of the conditions enhancing migration due to higher spring temperatures in the winter quarters and on theigratory route.
Abstract: Some of the factors that could influence changes in phenology of the song thrush (Turdus philomelos) during spring migration have been analyzed in relation to the timing of their return to the south-east Baltic region over the last 40 years. These include wind direction and velocity, temperature and precipitation in the wintering areas and along the migratory route. In March, a significant correlation was found between the timing of passage in the Baltic region and both the air temperatures in wintering area and winds over the migratory route. In April, when mass migration of thrushes occurs, the timing of passage was correlated with temperature, winds and, partly, precipitation over the route of migration. In this month, the frequency of tailwinds increased significantly along the route of migration from south-west France to the Baltic region over the last 40 years. The tailwind frequency was correlated with the beginning, middle and end of spring passage, accounting for 51% of the variance of median dates of the passage. The higher ambient temperatures over the migratory route explain nearly 20% of the variance in the timing of passage. Our results suggest that the advance in the timing of spring migration is primarily due to (1) the increased frequency of tailwinds favorable for migratory flights over the migratory route, and (2) the earlier emergence of the conditions enhancing migration due to higher spring temperatures in the winter quarters and on the migratory route.
TL;DR: Projected changes in fish communities suggest an adverse influence on salmonid sport fishing and a loss in its high economic value, which is to the authors' knowledge an unprecedented approach.
Abstract: This study assesses the impact of a changing climate on fish fauna by comparing the past mean state of fish assemblage to a possible future mean state. It is based on (1) local scale observations along an Inner-Alpine river called Mur, (2) an IPCC emission scenario (IS92a), implemented by atmosphere-ocean global circulation model (AOGCM) ECHAM4/OPYC3, and (3) a model-chain that links climate research to hydrobiology. The Mur River is still in a near-natural condition and water temperature in summer is the most important aquatic ecological constraint for fish distribution. The methodological strategy is (1) to use downscaled air temperature and precipitation scenarios for the first half of the twenty-first century, (2) to establish a model that simulates water temperature by means of air temperature and flow rate in order to generate water temperature scenarios, and (3) to evaluate the impact on fish communities using an ecological model that is driven by water temperature. This methodology links the response of fish fauna to an IPCC emission scenario and is to our knowledge an unprecedented approach. The downscaled IS92a scenarios show increased mean air temperatures during the whole year and increased precipitation totals during summer, but reduced totals for the rest of the annual cycle. These changes result in scenarios of increased water temperatures, an altered annual cycle of flow rate, and, in turn, a 70 m displacement in elevation of fish communities towards the river’s head. This would enhance stress on species that rely on low water temperatures and coerce cyprinid species into advancing against retreating salmonids. Hyporhithral river sectors would turn into epipotamal sectors. Grayling (Thymallus thymallus) and Danube salmon (Hucho hucho), presently characteristic for the Mur River, would be superceded by other species. Native brown trout (Salmo trutta), already now under pressure of competition, may be at risk of losing its habitat in favour of invaders like the exotic rainbow trout (Oncorhynchus mykiss), which are better adapted to higher water temperatures. Projected changes in fish communities suggest an adverse influence on salmonid sport fishing and a loss in its high economic value.
TL;DR: Based on differences in percentage of cattle panting in sprinkled and non-sprinkled treatments, sprinkling was found to have a positive effect on cattle feeding area microclimate and to reduce the susceptibility of cattle to hyperthermia, however, cattle acclimatization to being sprinkled can result in slighthyperthermia even during cooler days when sprinkling would normally not be utilized.
Abstract: Experiments were conducted to evaluate strategies designed to reduce heat stress of cattle. In the first experiment, cattle were sprinkled for 20 min every 1.5 h between 1000 hours and 1750 hours (WET) versus not sprinkled (DRY). In a second experiment, treatments consisted of: (1) control, no water application; (2) water applied to the pen surfaces between 1000 hours and 1200 hours (AM); and (3) water applied to pen surfaces between 1400 hours and 1600 hours (PM). In both experiments, sprinkling lowered (P < 0.05) mid-afternoon temperatures. In the first experiment, relative humidity (RH) of WET versus DRY pens differed (P < 0.05) and averaged 72.4 and 68.9%, respectively. The average temperature–humidity index (THI) in WET pens was 0.5 units lower (P < 0.05), than the THI in DRY pens. In the second experiment, RH in sprinkled pens was also greater (P < 0.05) than RH in control (CON) pens However, THI differed (P < 0.05) among treatments, being 81.5, 80.9, and 80.3, respectively for CON, AM, and PM. Pens with sprinklers had a larger percentage of steers in areas where sprinkling took place, even on days when sprinkling had not occurred. Based on differences in percentage of cattle panting in sprinkled and non-sprinkled treatments, sprinkling was found to have a positive effect on cattle feeding area microclimate and to reduce the susceptibility of cattle to hyperthermia. However, cattle acclimatization to being sprinkled can result in slight hyperthermia even during cooler days when sprinkling would normally not be utilized.
TL;DR: It is found that air mass types have independent effects on mortality for both the cold and warm season and may be used to predict weather-related adverse health effects.
Abstract: In this study, we examined the short-term effects of air mass types on mortality in Athens, Greece. An objective air mass types classification was used, based on meteorological parameters measured at the surface. Mortality data were treated with generalized additive models (GAM) and extending Poisson regression, using a LOESS smoother to control for the confounding effects of seasonal patterns, adjusting also for temperature, long-term trends, day of the week, and ambient particle concentrations. The introduced air mass classification explains the daily variation of mortality to a statistically significant degree. The highest daily mortality was observed on days characterized by southerly flow conditions for both the cold (increase in relative risk for mortality 9%; with a 95% confidence interval: 3–14%), and the warm period (7%; with a 95% confidence interval: 2–13%) of the year. The northeasterly flow is associated with the lowest mortality. Effects on mortality, independent of temperature, are observed mainly for lag 0 during the cold period, but persist longer during the warm period. Not adjusting for temperature and/or ambient particle levels slightly alters the results, which then reflect the known temperature and particle effects, already reported in the literature. In conclusion, we find that air mass types have independent effects on mortality for both the cold and warm season and may be used to predict weather-related adverse health effects.
TL;DR: Results indicated that when local pollen is low, the incoming pollen has a competitive advantage and the level of outcross is significantly greater than when theLocal pollen is abundant.
Abstract: The development of maize (Zea mays L.) varieties as factories of pharmaceutical and industrial compounds has renewed interest in controlling pollen dispersal. The objective of this study was to compare gene flow into maize fields of different local pollen densities under the same environmental conditions. Two fields of approximately 36 ha were planted with a nontransgenic, white hybrid, in Ankeny, Iowa, USA. In the center of both fields, a 1-ha plot of a yellow-seeded stacked RR/Bt transgenic hybrid was planted as a pollen source. Before flowering, the white receiver maize of one field was detasseled in a 4:1 ratio to reduce the local pollen density (RPD). The percentage of outcross in the field with RPD was 42.2%, 6.3%, and 1.3% at 1, 10, and 35 m from the central plot, respectively. The percentage of outcross in the white maize with normal pollen density (NPD) was 30.1%, 2.7%, and 0.4%, respectively, at these distances. At distances greater than 100 m, the outcross frequency decreased below 0.1 and 0.03% in the field with RPD and NPD, respectively. A statistical model was used to compare pollen dispersal based on observed outcross percentages. The likelihood ratio test confirmed that the models of outcrossing in the two fields were significantly different (P is practically 0). Results indicated that when local pollen is low, the incoming pollen has a competitive advantage and the level of outcross is significantly greater than when the local pollen is abundant.
TL;DR: The behaviour of rectal temperature, breathing rate and the parameters of the acid-base status indicated that the suffering of the cows was on the borderline between mild and high heat stress during the hotter periods only, according to the climatic conditions in the two years.
Abstract: In two consecutive summers, 21 and 18 cows respectively were monitored for acid-base chemistry and some blood minerals, to assess their variation according to the level of heat stress at different stages of lactation. During both years, the cows were monitored according to their lactation phase (early, mid-, and late) at the beginning of the summer. Climatic conditions were described through the temperature humidity index. Cows were monitored weekly for: breathing rate, rectal temperature, hemogas parameters and blood minerals (morning and afternoon collection). In the first year, two hotter periods were identified, with more severe conditions in the second one, when cows had rectal temperatures higher than 40 degrees C. In the second year, only one hotter period was identified, with a heat stress comparable to that of the first period of the first year. The behaviour of rectal temperature, breathing rate and the parameters of the acid-base status indicated that the suffering of the cows was on the borderline between mild and high heat stress during the hotter periods only, according to the climatic conditions in the two years. During the hotter periods, the acid-base chemistry differed significantly with a reduction of HCO3- and an increase of Cl during the hotter hours of the day. The compensation mechanism for mild alkalosis during hotter hours maintained blood pH and the HCO3- returned to normal values during the night. Significant reductions were observed for Mg and Zn during the hotter periods. The cows in late lactation appeared to be less stressed by the hot climate.
TL;DR: New Zealand’s climate appears more forgiving than that of the Canadian Maritimes, as the model predicts a wider range of oviposition dates leading to stable seasonality, and climate change scenarios show an increase in probability of establishment throughout New Zealand.
Abstract: The gypsy moth is a global pest that has not yet established in New Zealand despite individual moths having been discovered near ports. A climate-driven phenology model previously used in North America was applied to New Zealand. Weather and elevation data were used as inputs to predict where sustainable populations could potentially exist and predict the timing of hatch and oviposition in different regions. Results for New Zealand were compared with those in the Canadian Maritimes (New Brunswick, Nova Scotia, and Prince Edward Island) where the gypsy moth has long been established. Model results agree with the current distribution of the gypsy moth in the Canadian Maritimes and predict that the majority of New Zealand’s North Island and the northern coastal regions of the South Island have a suitable climate to allow stable seasonality of the gypsy moth. New Zealand’s climate appears more forgiving than that of the Canadian Maritimes, as the model predicts a wider range of oviposition dates leading to stable seasonality. Furthermore, we investigated the effect of climate change on the predicted potential distribution for New Zealand. Climate change scenarios show an increase in probability of establishment throughout New Zealand, most noticeably in the South Island.
TL;DR: The results allow us to caution that cylindrical sensors may overestimate wetness for operational LWD measurements in humid climates and that the effect of other protocols for angling or positioning this sensor should be investigated for different crops.
Abstract: In general, leaf wetness duration (LWD) is a key parameter influencing plant disease epidemiology, since it provides the free water required by pathogens to infect foliar tissue. LWD is used as an input in many disease warning systems, which help growers to decide the best time to spray their crops against diseases. Since there is no observation standard either for sensor or exposure, LWD measurement is often problematic. To assess the performance of electronic sensors, LWD measurements obtained with painted cylindrical and flat plate sensors were compared under different field conditions in Elora, Ontario, Canada, and in Piracicaba, Sao Paulo, Brazil. The sensors were tested in four different crop environments—mowed turfgrass, maize, soybean, and tomatoes—during the summer of 2003 and 2004 in Elora and during the winter of 2005 in Piracicaba. Flat plate sensors were deployed facing north and at 45° to horizontal, and cylindrical sensors were deployed horizontally. At the turfgrass site, both sensors were installed 30 cm above the ground, while at the crop fields, the sensors were installed at the top and inside the canopy (except for maize, with a sensor only at the top). Considering the flat plate sensor as a reference (Sentelhas et al. Operational exposure of leaf wetness sensors. Agric For Meteorol 126:59–72, 2004a), the results in the more humid climate at Elora showed that the cylindrical sensor overestimated LWD by 1.1–4.2 h, depending on the crop and canopy position. The main cause of the overestimation was the accumulation of big water drops along the bottom of the cylindrical sensors, which required much more energy and, consequently, time to evaporate. The overall difference between sensors when evaporating wetness formed during the night was around 1.6 h. Cylindrical sensors also detected wetness earlier than did flat plates—around 0.6 h. Agreement between plate and cylinder sensors was much better in the drier climate at Piracicaba. These results allow us to caution that cylindrical sensors may overestimate wetness for operational LWD measurements in humid climates and that the effect of other protocols for angling or positioning this sensor should be investigated for different crops.
TL;DR: A mathematical model was developed to determine the air temperature at which an average adult, wearing a specific outdoor clothing and engaging in a given activity, attains thermal comfort under outdoor environment condition, and indicated low clothing insulation, less physical activity and high wind speed lead to high air temperature prediction for thermal comfort.
Abstract: Current thermal comfort indices do not take into account the effects of wind and body movement on the thermal resistance and vapor resistance of clothing. This may cause public health problem, e.g. cold-related mortality. Based on the energy balance equation and heat exchanges between a clothed body and the outdoor environment, a mathematical model was developed to determine the air temperature at which an average adult, wearing a specific outdoor clothing and engaging in a given activity, attains thermal comfort under outdoor environment condition. The results indicated low clothing insulation, less physical activity and high wind speed lead to high air temperature prediction for thermal comfort. More accurate air temperature prediction is able to prevent wearers from hypothermia under cold conditions.
TL;DR: This study focussed on the reconstruction of daily broad-band UV-B (280–315 nm), UV-A (315–400 nm) and erythemal UV irradiation (ER) due to the rapid changes in cloudiness at mid-latitude sites, solar UV irradiance exhibits appreciable short-term variability.
Abstract: Long-term records of solar UV radiation reaching the Earth's surface are scarce. Radiative transfer calculations and statistical models are two options used to reconstruct decadal changes in solar UV radiation from long-term records of measured atmospheric parameters that contain information on the effect of clouds, atmospheric aerosols and ground albedo on UV radiation. Based on earlier studies, where the long-term variation of daily solar UV irradiation was derived from measured global and diffuse irradiation as well as atmospheric ozone by a non-linear regression method [Feister et al. (2002) Photochem Photobiol 76:281-293], we present another approach for the reconstruction of time series of solar UV radiation. An artificial neural network (ANN) was trained with measurements of solar UV irradiation taken at the Meteorological Observatory in Potsdam, Germany, as well as measured parameters with long-term records such as global and diffuse radiation, sunshine duration, horizontal visibility and column ozone. This study is focussed on the reconstruction of daily broad-band UV-B (280-315 nm), UV-A (315-400 nm) and erythemal UV irradiation (ER). Due to the rapid changes in cloudiness at mid-latitude sites, solar UV irradiance exhibits appreciable short-term variability. One of the main advantages of the statistical method is that it uses doses of highly variable input parameters calculated from individual spot measurements taken at short time intervals, which thus do represent the short-term variability of solar irradiance.