首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 10 毫秒
1.
The eastern Mediterranean and Middle East, a region with diverse socioeconomic and cultural identities, is exposed to strong climatic gradients between its temperate north and arid south. Model projections of the twenty-first century indicate increasing hot weather extremes and decreasing rainfall. We present model results, which suggest that across the Balkan Peninsula and Turkey climate change is particularly rapid, and especially summer temperatures are expected to increase strongly. Temperature rise can be amplified by the depletion of soil moisture, which limits evaporative cooling, prompted by the waning of large-scale weather systems that generate rain. Very hot summers that occurred only rarely in the recent past are projected to become common by the middle and the end of the century. Throughout the region, the annual number of heat wave days may increase drastically. Furthermore, conditions in the region are conducive for photochemical air pollution. Our model projections suggest strongly increasing ozone formation, a confounding health risk factor particularly in urban areas. This adds to the high concentrations of aerosol particles from natural (desert dust) and anthropogenic sources. The heat extremes may have strong impacts, especially in the Middle East where environmental stresses are plentiful.  相似文献   

2.
Three types of sea alga distributed along the Syrian coast have been collected and analyzed for radioactivity and trace elements. Results have shown that (137)Cs concentrations in all the analyzed sample were relatively low (less than 1.2 Bq kg(-1) dry weight) while the levels of naturally occurring radionuclides, such as (210)Po and (210)Pb, were found to be high in most samples; the highest observed value (27.43 Bq kg(-1) dry weight) for (210)Po being in the red Jania longifurca alga. In addition, most brown alga species were also found to accumulate (210)Po, which indicates their selectivity to this isotope. On the other hand, brown alga (Cystoseira and Sargassum Vulgare) have shown a clear selectivity for some trace metals such as Cr, As, Cu and Co, this selectivity may encourage their use as biomonitor for pollution by trace metals. Moreover, the red alga species were found to contain the highest levels of Mg while the brown alga species were found to concentrate Fe, Mn, Na and K and nonmetals such as Cl, I and Br.  相似文献   

3.
Regional Environmental Change - In addition to periodic long-term drought, much of Central America experiences a rainy season with two peaks separated by a dry period of weeks to over a month in...  相似文献   

4.
Vertical distribution and inventories of (137)Cs have been determined using radiocesium distributions in presumably undistributed soil profiles, collected from 36 sites distributed all over Syria (eastern Mediterranean region). Vertical distributions of (137)Cs in the collected profiles were found to be strongly correlated with soil type and five groups were identified. Based on these profiles, total (137)Cs inventory (bomb test and Chernobyl) varied between 320 Bq m(-2) and 9,647 Bq m(-2). Geographical mapping of (137)Cs inventories showed that the highest values were found in the coastal, middle and north-east regions of Syria indicating that Chernobyl atmospheric contribution to the total (137)Cs deposition in the region is predominant. In contrast, the lowest values were found in the south-east region (Syrian Badia), where a relatively uniform distribution was observed, which may only be attributed to the past global nuclear bomb test. The measured inventories were also compared with a mathematical model for estimating bomb derived (137)Cs reference inventories.  相似文献   

5.
The interaction between human and land in estuarine–coastal areas has become a focus of the global change research. Since the sixteenth century, the Old Huanghe River delta has experienced rapid accretion, the formation of rich ecological resources and diverse land use pattern changes; such information, in combination with a large number of historical documents, provides a unique research area for revealing the processes for ecosystem–human changes. We use historical documents and adopt multidisciplinary methods, to identify the relationship between ecosystem changes and human activities, on the basis of spatial and temporal analysis, for in the Old Huanghe River delta region. The results indicate that, in the sixteenth to nineteenth centuries, the long-term monopolistic development pattern under the government leadership, which occupied large quantities of ecological resources, controlled the coastal salt industry and marsh land exploitation. However, along with the delta ecosystem change and population growth, the development pattern became gradually unsustainable, i.e., the salt industry migrated toward the north, while the farming activities migrated toward the south with enhanced intensity of marsh reclamation. The government monopoly collapsed in the late nineteenth century, which enlarged the independent development space for the local residents, which, to a large extent, improved the land-use efficiency and reduced the population pressure.  相似文献   

6.
The data on the biological diversity, bioecological features, and geographic variations of segetal plants in the Middle Urals are presented for the first time. It has been shown that apophytic and anthropophytic groups are equally represented among them. Each group is characterized, and the phytocoenotic activity of segetal plants is considered.  相似文献   

7.
Landscape-climatic changes are described that took place in the second half of the Late Neopleistocene and Holocene on the eastern macroslope of the Northern Urals. On the basis of geochronological and palynological data, the composition of paleocommunities in different time sections over the past 50000 years has been reconstructed in detail. Paleoclimatic parameters calculated by the zonal-formation method are presented.  相似文献   

8.
The distribution of life forms in the dendroflora of the Russian Far East is discussed in connection with decrease in heat supply in the latitudinal (south-north) direction and the influence of the ocean in the longitudinal (east-west) direction. Emphasis is made on the uniqueness of the ratios between different life forms of the dendroflora at local and regional levels of the structural-functional organization of vegetation, which may be used for the purposes of environmental monitoring.  相似文献   

9.
Some specific features of the distribution of resident Chiroptera (10 forms) in the eastern East European Plain and adjacent areas (44°–65° N, 40°–60° E) are described. It is noted that in different seasons of the year,Myotis dasycneme, M. daubentonii, M. nattereri, M. mystacinus, M. brandtii, Plecotus auritus, Eptesicus nilssoni, andE. serotinus serotinus are found more often in upland areas with karst and other erosional forms of relief, whereasE. serotinus turcomanus andPipistrellus kuhlii display no preference for these types of relief.  相似文献   

10.
Regional Environmental Change - The Middle East and North Africa (MENA) region emerges as one of the hot spots for worsening extreme heat, drought and aridity conditions under climate change. A...  相似文献   

11.
12.
Bacterial community plays an important role in litter decomposition. Although the changes of bacterial community as litter decomposition proceeding can be regulated by frozen temperature and changed litter quality in cold regimes, little information has been available on. Therefore, the structure and diversity of the bacterial community in Minjiang fir (Abies faxoniana) needle litter were measured in an alpine forest in eastern Tibetan Plateau. The litter samples were sampled at the onset of the freezing stage, the deep freezing stage, the thawing stage, the early growing season and the late growing season from December 2010 to November 2011. The methods of real-time polymerase chain reaction (qPCR) coupled with denaturing gradient gel electrophoresis (DGGE) were used. The copy numbers of bacterial 16S rDNA in the fir needle litter changed significantly as litter decomposition proceeding. The abundance of bacterial 16S rDNA was significantly lower at the deep freezing stage but highest at the thawing stage. A large number of bands were observed on the DGGE gel; the intensities and distances of the bands were significantly different among the samples at different stages; the indexes of bacterial diversity at the onset of the freezing and deep freezing stages were lower than them at the other stages. All of the bacterial sequences were affiliated with six distinct classes and an unknown group. Redundancy analysis indicated that moisture, mass loss and the release of litter elements (e.g., C, N, P) exerted obvious influences over the bacterial communities.  相似文献   

13.
Vertical profiles of radioactive radon gas ((222)Rn) and dissolved gaseous mercury (DGM) in seawater in the Mediterranean Basin have been measured. They were found in the range 1.7-19.3 Bq m(-3) and 22-200 ng m(-3), respectively, at the bottom and 2.0-20.0 Bq m(-3) and 6-80 ng m(-3), respectively, at the surface. Preliminary results indicate a positive correlation between concentrations of both gases at some locations, but not at others. Further analyses will be performed, after (226)Ra contents in sediment and water have been determined, taking into account environmental parameters such as air and water temperatures, barometric pressure and water flow, in order to better interpret these profiles.  相似文献   

14.
15.
Environment, Development and Sustainability - Land-use and land-cover (LULC) change as a result of rapid urban expansion cause land surface temperature (LST) variations. The study aims to analyze...  相似文献   

16.
Changes in the frequency and intensity of cyclones and associated windstorms affecting the Mediterranean region simulated under enhanced Greenhouse Gas forcing conditions are investigated. The analysis is based on 7 climate model integrations performed with two coupled global models (ECHAM5 MPIOM and INGV CMCC), comparing the end of the twentieth century and at least the first half of the twenty-first century. As one of the models has a considerably enhanced resolution of the atmosphere and the ocean, it is also investigated whether the climate change signals are influenced by the model resolution. While the higher resolved simulation is closer to reanalysis climatology, both in terms of cyclones and windstorm distributions, there is no evidence for an influence of the resolution on the sign of the climate change signal. All model simulations show a reduction in the total number of cyclones crossing the Mediterranean region under climate change conditions. Exceptions are Morocco and the Levant region, where the models predict an increase in the number of cyclones. The reduction is especially strong for intense cyclones in terms of their Laplacian of pressure. The influence of the simulated positive shift in the NAO Index on the cyclone decrease is restricted to the Western Mediterranean region, where it explains 10–50 % of the simulated trend, depending on the individual simulation. With respect to windstorms, decreases are simulated over most of the Mediterranean basin. This overall reduction is due to a decrease in the number of events associated with local cyclones, while the number of events associated with cyclones outside of the Mediterranean region slightly increases. These systems are, however, less intense in terms of their integrated severity over the Mediterranean area, as they mostly affect the fringes of the region. In spite of the general reduction in total numbers, several cyclones and windstorms of intensity unknown under current climate conditions are identified for the scenario simulations. For these events, no common trend exists in the individual simulations. Thus, they may rather be attributed to long-term (e.g. decadal) variability than to the Greenhouse Gas forcing. Nevertheless, the result indicates that high-impact weather systems will remain an important risk in the Mediterranean Basin.  相似文献   

17.
Regional Environmental Change - The recent (twentieth century) and future (twenty-first century) climate evolution in the Mediterranean region is analyzed in relation to annual mean global surface...  相似文献   

18.
Regional Environmental Change - To address sustainability challenges of agro-ecosystems located in Mediterranean urban regions, this paper focuses on the multidisciplinary subject of urban...  相似文献   

19.
Zou  Ye-Ai  Tang  Yue  Xie  Yong-Hong  Zhao  Qi-Hong  Zhang  Hong 《Regional Environmental Change》2017,17(3):879-888
Regional Environmental Change - The majority of Eastern China’s herbivorous geese overwinter in the East Dongting Lake, China, and there is growing concern about how changes in their habitats...  相似文献   

20.
This study links climate change impacts to the development of adaptation strategies for agriculture on the Mediterranean region. Climate change is expected to intensify the existing risks, particularly in regions with current water scarcity, and create new opportunities for improving land and water management. These risks and opportunities are characterised and interpreted across Mediterranean areas by analysing water scarcity pressures and potential impacts on crop productivity over the next decades. The need to respond to these risks and opportunities is addressed by evaluating an adaptive capacity index that represents the ability of Mediterranean agriculture to respond to climate change. We propose an adaptive capacity index with three major components that characterise the economic capacity, human and civic resources, and agricultural innovation. These results aim to assist stakeholders as they take up the adaptation challenge and develop measures to reduce the vulnerability of the sector to climate change.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号