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Heat Wave (heat + wave)
Selected AbstractsSpecies richness and susceptibility to heat and drought extremes in synthesized grassland ecosystems: compositional vs physiological effectsFUNCTIONAL ECOLOGY, Issue 6 2004L. VAN PEER Summary 1We investigated effects of declining plant species richness (S) on resistance to extremes in grassland communities. 2Synthesized model ecosystems of different S, grown outdoors in containers, were exposed to a stress peak combining heat and drought. The heat wave was induced experimentally by infrared irradiation in free air conditions. 3Before the heat wave, the more species-rich communities produced more biomass as a result of a large and positive complementarity effect that outweighed a small negative selection effect. 4Water use during the heat wave was likewise enhanced by S, which could not be attributed to dominance of ,water-wasting' species. Instead, water consumption at high S exceeded that expected from changes in community biomass and biomass composition. The observed enhancement of resource (water) acquisition under stress with increasing S therefore probably originated from complementarity. 5Despite enhanced water use in the more diverse communities, plant survival was significantly less, affecting all species alike. Physiological stress, recorded as photochemical efficiency of photosystem II electron transport, was significantly greater. Before the heat wave, the changes in biomass composition that coincided with increasing S did not favour species that would later prove intrinsically sensitive or insensitive. 6Complementarity in resource use for biomass production had a cost in terms of reduced survival under stress, despite the likelihood of complementarity in water acquisition during exposure. The greater loss of individuals from the more diverse grasslands suggests enhanced risk of local extinction. [source] Mass mortality in Northwestern Mediterranean rocky benthic communities: effects of the 2003 heat waveGLOBAL CHANGE BIOLOGY, Issue 5 2009J. GARRABOU Abstract Late in summer 2003, extensive mass mortality of at least 25 rocky benthic macro-invertebrate species (mainly gorgonians and sponges) was observed in the entire Northwestern (NW) Mediterranean region, affecting several thousand kilometers of coastline. We were able to characterize the mortality event by studying six areas covering the main regions of the NW Mediterranean basin. The degree of impact on each study area was quantified at 49 sites by estimating the proportion of colonies affected in populations of several gorgonian species compared with reference data obtained in years without mortality signs. According to these data, the western areas (Catalan coast and Balearic Islands) were the least affected, while the central areas (Provence coast and Corsica-Sardinia) showed a moderate impact. The northernmost and eastern areas (Gulf of Genoa and Gulf of Naples) displayed the highest impact, with almost 80% of gorgonian colonies affected. The heat wave of 2003 in Europe caused an anomalous warming of seawater, which reached the highest temperatures ever recorded in the studied regions, between 1 and 3 °C above the climatic values (mean and maximum). Because this exceptional warming was observed in the depth ranges most affected by the mortality, it seems likely that the 2003 anomalous temperature played a key role in the observed mortality event. A correlation analysis between temperature conditions and degree of impact seems to support this hypothesis. Under the present climate warming trend, new mass mortality events may occur in the near future, possibly driving a major biodiversity crisis in the Mediterranean Sea. [source] Performance of High Arctic tundra plants improved during but deteriorated after exposure to a simulated extreme temperature eventGLOBAL CHANGE BIOLOGY, Issue 12 2005Fleur L. Marchand Abstract Arctic ecosystems are known to be extremely vulnerable to climate change. As the Intergovernmental Panel on Climate Change scenarios project extreme climate events to increase in frequency and severity, we exposed High Arctic tundra plots during 8 days in summer to a temperature rise of approximately 9°C, induced by infrared irradiation, followed by a recovery period. Increased plant growth rates during the heat wave, increased green cover at the end of the heat wave and higher chlorophyll concentrations of all four predominating species (Salix arctica Pall., Arctagrostis latifolia Griseb., Carex bigelowii Torr. ex Schwein and Polygonum viviparum L.) after the recovery period, indicated stimulation of vegetative growth. Improved plant performance during the heat wave was confirmed at plant level by higher leaf photochemical efficiency (Fv/Fm) and at ecosystem level by increased gross canopy photosynthesis. However, in the aftermath of the temperature extreme, the heated plants were more stressed than the unheated plants, probably because they acclimated to warmer conditions and experienced the return to (low) ambient as stressful. We also calculated the impact of the heat wave on the carbon balance of this tundra ecosystem. Below- and aboveground respiration were stimulated by the instantaneous warmer soil and canopy, respectively, outweighing the increased gross photosynthesis. As a result, during the heat wave, the heated plots were a smaller sink compared with their unheated counterparts, whereas afterwards the balance was not affected. If other High Arctic tundra ecosystems react similarly, more frequent extreme temperature events in a future climate may shift this biome towards a source. It is uncertain, however, whether these short-term effects will hold when C exchange rates acclimate to higher average temperatures. [source] Europe's 2003 heat wave: a satellite view of impacts and land,atmosphere feedbacksINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2006Benjamin F. Zaitchik Abstract A combination of satellite imagery, meteorological station data, and the NCEP/NCAR reanalysis has been used to explore the spatial and temporal evolution of the 2003 heat wave in France, with focus on understanding the impacts and feedbacks at the land surface. Vegetation was severely affected across the study area, especially in a swath across central France that corresponds to the Western European Broadleaf (WEB) Forests ecological zone. The remotely sensed surface temperature anomaly was also greatest in this zone, peaking at +15.4 °C in August. On a finer spatial scale, both the vegetation and surface temperature anomalies were greater for crops and pastures than for forested lands. The heat wave was also associated with an anomalous surface forcing of air temperature. Relative to other years in record, satellite-derived estimates of surface-sensible heat flux indicate an enhancement of 48,61% (24.0,30.5 W m,2) in WEB during the August heat wave maximum. Longwave radiative heating of the planetary boundary layer (PBL) was enhanced by 10.5 W m,2 in WEB for the same period. The magnitude and spatial structure of this local heating is consistent with models of the late twenty-first century climate in France, which predict a transitional climate zone that will become increasingly affected by summertime drought. Models of future climate also suggest that a soil-moisture feedback on the surface energy balance might exacerbate summertime drought, and these proposed feedback mechanisms were tested using satellite-derived heat budgets. Copyright © 2006 Royal Meteorological Society. [source] Temporal fluctuations in heat waves at Prague,Klementinum, the Czech Republic, from 1901,97, and their relationships to atmospheric circulationINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2002Jan Kyselı Abstract Temporal fluctuations in heat wave occurrence and severity are analysed in long-term daily temperature series at Prague,Klementinum, the Czech Republic. Although the observations have been continuous since 1775, the period 1901,97 with the most credible data is mainly examined. Most of the warmest summers of the 20th century appeared within the periods 1943,52 and 1992,95; the temporal distribution of heat waves corresponds to this pattern and shows two maxima, in the 1940s to early 1950s and in the 1990s. A very low occurrence of heat waves was typical of the beginning of the 20th century and around 1980. The peak of heat wave severity in the 1940s,early 1950s, as well as their almost total absence in the first two decades of the 20th century, may be a common feature for a large area, as indicated by the comparison between two stations within central Europe, Prague,Klementinum and Basel (Switzerland), and by other studies. An extraordinary heat wave occurred in July and August 1994. It greatly exceeded other heat waves, mainly in the much higher cumulative temperature excess above 30°C and a record-breaking duration of a continuous period of tropical days. Relationships between heat wave characteristics in warm and cold decades and circulation conditions were analysed using the subjective Hess,Brezowsky catalogue of weather types (Grosswetterlagen). The link to the atmospheric circulation is evident, e.g. situations with an anticyclone or a ridge over central Europe were more (less) frequent during all the warm (cold) decades. Moreover, the occurrence of long and severe heat waves in the 1990s may reflect an enhanced persistence of the atmospheric circulation over Europe in the summer season because all groups of weather types have considerably increased residence times in 1988,97 compared with long-term means. Copyright © 2002 Royal Meteorological Society [source] Regional climate modulates the canopy mosaic of favourable and risky microclimates for insectsJOURNAL OF ANIMAL ECOLOGY, Issue 3 2007SYLVAIN PINCEBOURDE Summary 1,One major gap in our ability to predict the impacts of climate change is a quantitative analysis of temperatures experienced by organisms under natural conditions. We developed a framework to describe and quantify the impacts of local climate on the mosaic of microclimates and physiological states of insects within tree canopies. This approach was applied to a leaf mining moth feeding on apple leaf tissues. 2,Canopy geometry was explicitly considered by mapping the 3D position and orientation of more than 26 000 leaves in an apple tree. Four published models for canopy radiation interception, energy budget of leaves and mines, body temperature and developmental rate of the leaf miner were integrated. Model predictions were compared with actual microclimate temperatures. The biophysical model accurately predicted temperature within mines at different positions within the tree crown. 3,Field temperature measurements indicated that leaf and mine temperature patterns differ according to the regional climatic conditions (cloudy or sunny) and depending on their location within the canopy. Mines in the sun can be warmer than those in the shade by several degrees and the heterogeneity of mine temperature was incremented by 120%, compared with that of leaf temperature. 4.,The integrated model was used to explore the impact of both warm and exceptionally hot climatic conditions recorded during a heat wave on the microclimate heterogeneity at canopy scale. During warm conditions, larvae in sunlight-exposed mines experienced nearly optimal growth conditions compared with those within shaded mines. The developmental rate was increased by almost 50% in the sunny microhabitat compared with the shaded location. Larvae, however, experienced optimal temperatures for their development inside shaded mines during extreme climatic conditions, whereas larvae in exposed mines were overheating, leading to major risks of mortality. 5,Tree canopies act as both magnifiers and reducers of the climatic regime experienced in open air outside canopies. Favourable and risky spots within the canopy do change as a function of the climatic conditions at the regional scale. The shifting nature of the mosaic of suitable and risky habitats may explain the observed uniform distribution of leaf miners within tree canopies. [source] Did thirst-blockers like angiotensin-converting-enzyme inhibitors, sartans, serotonine-re-uptake-inhibitors, dopamine agonists/antagonists, or atypical neuroleptics contribute to the exorbitant number of fatalities during the French 2003 heat wave?PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 11 2007Dr Claudia Stöllberger MD Univ. No abstract is available for this article. [source] Ecophysiological and morphological parameters related to survival in grass species exposed to an extreme climatic eventPHYSIOLOGIA PLANTARUM, Issue 4 2005Ann Milbau An experiment was performed to elucidate interspecific differences in survival time of grass species subjected to an extreme climatic event. We exposed eight grass species to a simulated heat wave in the field (,free air' temperature increase at 11°C above ambient) combined with drought. We determined whether interspecific differences in survival time were related to the responses of the species to the imposed stress or could be explained by their ecophysiological or morphological characteristics in unstressed conditions. Surprisingly, there was no effect of specific leaf area, but species with a higher total leaf area survived longer. This may arise from a greater water reserve in the plant as a whole, which could delay the desiccation of the meristem, or from reduced evaporation due to a higher leaf area index. Species in which the decrease in light-saturated stomatal conductance (gs) and photosynthetic CO2 uptake rate (Amax) was strongly related to the decrease in soil water availability (measured as soil relative water content and stress duration) survived longer than species in which gs and Amax likewise declined but responded more to daily fluctuations in irradiance, temperature, and vapor pressure deficit during the heat wave. We, therefore, hypothesize that interspecific differences in stress survival time might be related to the extent to which stomata react to changes in soil water conditions relatively to changes in other environmental and physiological factors. The results suggest that resistance to extremes is governed by other mechanisms than resistance to moderate drought. [source] Physiological Responses of Forest Trees to Heat and DroughtPLANT BIOLOGY, Issue 5 2006H. Rennenberg Abstract: The heat wave of summer 2003 was the largest and the most persistent ever experienced in Central Europe and has fuelled concern about the effects of climate change on European ecosystems. Since forests constitute the most important European ecosystems, in this review article we assess current knowledge on the effects of heat and drought on key metabolic processes for growth and productivity of forest trees. In particular, the general consequences of heat and drought on (1) photosynthesis and respiration at the cellular and community level, and (2) on nutrient uptake, partitioning and competition for nutrients are summarized. The latter are a major sink for photosynthetic energy and, therefore, are indirectly but strongly connected to the performance of photosynthesis. In addition, the interaction of heat and drought with stress compensation mechanisms and emission of biogenic volatile organic compounds (BVOC) are discussed, since these processes are directly connected to carbon metabolism. Effects on the emission of BVOC are also included because they constitute an important feedback mechanism on ozone formation and, thus, on atmospheric pollution. As far as available, data collected during the 2003 heat wave are included and discussed. [source] Rapid range expansion of a wing-dimorphic bush-cricket after the 2003 climatic anomalyBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009AXEL HOCHKIRCH During recent decades, many species have responded to global warming by poleward range expansions. We require a better mechanistic understanding of the nature and extent of such processes to assess how climate change might affect biodiversity. Wing-dimorphic bush-crickets are excellent objects to study dispersal and colonization processes at the range margin because the long-winged morphs (macropters) represent dispersal units of otherwise flightless species. Moreover, these insects produce noisy songs and can easily be mapped. The present study comprised a detailed investigation of the population dynamics and genetics at the edge of the range of Roesel's bush-cricket, Metrioptera roeselii. We mapped the distribution of this insect in a previously unoccupied area of 185 km2 and examined the genetic structure at the range margin using four polymorphic microsatellite loci. The results obtained demonstrate that the European heat wave in 2003 induced a strong immigration of macropters in the area stemming from multiple sources, whereas only few immigrants were recorded in the two subsequent years. Macropters were genotyped in a distance of up to 19.1 km from their origin, considerably exceeding the known dispersal distances for this species. Moreover, the data show that strong local founder effects are equalized on a large scale by the high number of immigrants from multiple sources. The present study demonstrates that macropters are of high significance for the range expansion of wing-dimorphic insects because a single-year climatic anomaly can induce strong dispersal processes. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 118,127. [source] AIChE offers technological insights to the public policy debate on global climate changeENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2000David E. Gushee Global climate change has been a major issue on the national political agenda since 1988. Several Committees on Capitol Hill conducted hearings concerning the heat waves then searing the nation. Testimony by several well-regarded scientists at those hearings that "we ain't seen nothing yet" led to impressive headlines in the national media. Since then, unusually high temperatures, a succession of forecasts of serious negative impacts from the projected continued warming, and well-publicized Congressional hearings led to the creation of the United Nation's Framework Convention on Climate Change (FCCC) and its Kyoto Protocol. As a result, climate change is on just about every technology organization's agenda. In 1996, the American Institute of Chemical Engineers joined the list of organizations formally responding to the issue. The Government Relations Committee (GRC) formed a Task Force on Climate Change, made up of Institute members active in a number of aspects of the issue area. The charge to the Task Force: Look for opportunities for the Institute to contribute to the public policy debate on the issue and frame position papers accordingly. The first major conclusion of the Task Force was that AIChE is not in a position to state whether or not global climate change is a real public policy problem. However, to the extent that the public policy process treats climate change as an issue, the Institute is well positioned to comment on the technical merits of proposed policy responses. The Task Force recommended this posture to the GRC, which agreed. [source] Current and Future Trends of Climatic Extremes in SwitzerlandGEOGRAPHY COMPASS (ELECTRONIC), Issue 4 2007Martin Beniston This article provides an overview of extreme climatic events that are a feature of current and future climate that require full understanding if they are to be assessed in terms of social and economic costs. A review is made of the type of events that are important in mid-latitudes, with examples taken from the heat waves, floods and wind-storms that have affected Switzerland during the twentieth century. Regional climate model results are also presented for a scenario conducted over Europe. These simulations suggest that there may be significant shifts in the frequency and intensity of many forms of extremes as a warmer global climate progressively replaces current climate. In view of the potential losses in human, economic and environmental terms, extreme events and their future evolution need to carefully assessed in order to formulate appropriate adaptation strategies aimed at minimizing the negative impacts that extremes are capable of generating. [source] Changes in hot days and heat waves in China during 1961,2007INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2010Ting Ding Abstract Based on the daily maximum temperature (DMT) records at 512 stations during 1961,2007, the geographical patterns and temporal variations of hot days (HDs) and heat waves (HWs, including those persisting for 3,5 days and longer) over mainland China were studied. The HD (and hence HW) was defined in two ways, one by an absolute criterion, DMT > 35 °C, as applied in the nationwide meteorological agencies and another in a relative sense, DMT > the 90th percentile threshold of a local daily temperature distribution around the day. Two centers of high frequencies (over 5 days per year) of the absolute HDs during June,September were found in the regions of Xinjiang and the mid-lower reaches of the Yangtze River. The highest frequencies of the absolute HWs were about 1.5 times per year in the Xinjiang region and to the south of the mid-lower reaches of the Yangtze River. The frequencies of the relative HWs were about 1,1.5 times per year in most of China. The HDs and HWs increased significantly during the studied period in most of China, especially over the southeastern coast and northern China (by over 4 days per decade for relative HDs and 0.4 times per decade for relative HWs), but decreased significantly at some stations in the lower reaches of the Yellow River. Over most of China except northwestern China, the frequency of HDs was high during the 1960s,1970s, low in the 1980s, and high afterwards, with strong interannual variations. A remarkable increasing trend of HDs occurred after the 1990s in all regions. The changes in HDs and HWs were closely related to those in rain days and atmospheric circulation patterns at the interannual and interdecadal scales. Copyright © 2009 Royal Meteorological Society [source] Temporal fluctuations in heat waves at Prague,Klementinum, the Czech Republic, from 1901,97, and their relationships to atmospheric circulationINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2002Jan Kyselı Abstract Temporal fluctuations in heat wave occurrence and severity are analysed in long-term daily temperature series at Prague,Klementinum, the Czech Republic. Although the observations have been continuous since 1775, the period 1901,97 with the most credible data is mainly examined. Most of the warmest summers of the 20th century appeared within the periods 1943,52 and 1992,95; the temporal distribution of heat waves corresponds to this pattern and shows two maxima, in the 1940s to early 1950s and in the 1990s. A very low occurrence of heat waves was typical of the beginning of the 20th century and around 1980. The peak of heat wave severity in the 1940s,early 1950s, as well as their almost total absence in the first two decades of the 20th century, may be a common feature for a large area, as indicated by the comparison between two stations within central Europe, Prague,Klementinum and Basel (Switzerland), and by other studies. An extraordinary heat wave occurred in July and August 1994. It greatly exceeded other heat waves, mainly in the much higher cumulative temperature excess above 30°C and a record-breaking duration of a continuous period of tropical days. Relationships between heat wave characteristics in warm and cold decades and circulation conditions were analysed using the subjective Hess,Brezowsky catalogue of weather types (Grosswetterlagen). The link to the atmospheric circulation is evident, e.g. situations with an anticyclone or a ridge over central Europe were more (less) frequent during all the warm (cold) decades. Moreover, the occurrence of long and severe heat waves in the 1990s may reflect an enhanced persistence of the atmospheric circulation over Europe in the summer season because all groups of weather types have considerably increased residence times in 1988,97 compared with long-term means. Copyright © 2002 Royal Meteorological Society [source] Development of a high resolution daily gridded temperature data set (1969,2005) for the Indian regionATMOSPHERIC SCIENCE LETTERS, Issue 4 2009A. K. Srivastava Abstract A high resolution daily gridded temperature data set for the Indian region was developed using temperature data of 395 quality controlled stations for the period 1969,2005. A modified version of the Shepard's angular distance weighting algorithm was used for interpolating the station temperature data into 1° latitude × 1° longitude grids. Using the cross validation, errors were estimated and found less than 0.5 °C. The data set was also compared with another high resolution data set and found comparable. Mean frequency of cold and heat waves, temperature anomalies associated with the monsoon breaks have been presented. Copyright © 2009 Royal Meteorological Society [source] | ||||||||||||||||