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991.
992.
M. Teresa Pardo M.A. Esteve A. Gimnez J. Martínez-Fernndez M.F. Carreo J. Serrano J. Miano 《Journal of Arid Environments》2008,72(10):1803-1810
Changes in wandering beetle assemblages (Carabidae and Tenebrionidae) of different habitats situated in coastal wetlands of a Mediterranean arid area (Mar Menor, SE Spain) were analysed in 1984, 1992 and 2003 by pitfall trapping. Over two decades, the increase in irrigated lands at watershed scale led to rising water tables in the Mar Menor wetlands, which affected their beetle communities. These hydrological changes caused an increase in the carabid population, particularly in the sites most affected by flooding, where halobionts and halophiles, which were practically absent in 1984 and 1992, had become dominant by 2003. In contrast, tenebrionid assemblages simplified with time and by 2003 were dominated by one or two generalist species. 相似文献
993.
994.
PAUL J. KALDJIAN 《Geographical review》2004,94(3):284-304
ABSTRACT. For centuries, a network of market gardens throughout Istanbul provisioned the city with fresh vegetables. These bostans and their gardeners held a respected place in Istanbul life, contributing to the city's food and employment needs. Today, only fragments remain. Massive urban development, intense competition for metropolitan space, modernization, changing institutions and laws, and the global industrialization of food have threatened this tradition with extinction. But in spite of the overwhelming forces behind their demise, some of Istanbul's bostans persist. Efforts to support and promote the gardens, and to draw from the expertise and experience of their gardeners, are emerging. From a historical perspective, this article examines Istanbul's bostans to understand their meaning and contribution to the city's people and landscape. 相似文献
995.
The variability present in a 1/6th degree Atlantic ocean simulation forced by analysed wind stress and heat flux over a 20-year period is investigated by means of heat transport diagnostics. A section is defined which follows the Gulf Stream and its seaward extension, and transport of heat across this section is analysed to reveal the physical mechanisms responsible for intergyre heat exchanges on a variety of time scales. Heat transport across another section that crosses the Gulf Stream is also diagnosed to reveal the temporal behaviour of the gyre circulation. The Ekman response to wind stress variations accounts for the annual cycle and much of the interannual variability in both measures. For the intergyre heat transports, cancellation by transient-mean flow terms leads to a very weak annual cycle. Transient eddies account for approximately half the total intergyre transport of 0.7 Petawatts. They also account for a significant fraction of the interannual variability, but separate experiments with repeated-annual-cycle forcing indicate that the transient eddy component of the heat transport variability is internally generated. Links between the intergyre transport, the wind-driven gyre circulation, the surface heat budget and the atmospheric North Atlantic Oscillation are discussed. 相似文献
996.
997.
998.
F. N. Lisetskii Ya. V. Pavlyuk Zh. A. Kirilenko V. I. Pichura 《Russian Meteorology and Hydrology》2014,39(8):550-557
Presented are the development of the concept and projects of the basin nature management and the organization of their implementation in the whole region using the basin-administrative approach. Based on the multidimensional analysis and forecast of river runoff variations using the artificial neural networks, the typification of catchments is carried out mainly defined by such factors as its area, order of the river, and degree of anthropogenic load. Depending on the hydrological functioning type, the adapted complexes of Hydroecological activities are determined. The need in the integration of the geodata for each river basin with the inherent morphological and process characteristics as well as of the results of Hydroecological monitoring enables to recommend the structure of the database of the basin organization of nature management in the regions of Russia based on the European experience in the river network monitoring in the context of the EU Water Framework Directive and of the creation of the single infrastructure of the spatial data. 相似文献
999.
William F. Ruddiman 《Climatic change》2005,69(2-3):427-434
1000.
The nature of the reduction trend and quasi-decadal oscillation in Northern Hemisphere sea-ice extent is investigated. The trend and oscillation that seem to be two separate phenomena have been found in data. This study examines a hypothesis that the Arctic sea-ice reduction trend in the last three decades amplified the quasi-decadal Arctic sea-ice oscillation (ASIO) due to a positive ice/ocean-albedo feedback, based on data analysis and a conceptual model proposed by Ikeda et al. The theoretical, conceptual model predicts that the quasi-decadal oscillation is amplified by the thinning sea-ice, leading to the ASIO, which is driven by the strong positive feedback between the atmosphere and ice-ocean systems. Such oscillation is predicted to be out-of-phase between the Arctic Basin and the Nordic Seas with a phase difference of 3/4, with the Nordic Seas leading the Arctic. The wavelet analysis of the sea ice data reveals that the quasi-decadal ASIO occurred actively since the 1970s following the trend starting in the 1960s (i.e., as sea-ice became thinner and thinner), as the atmosphere experienced quasi-decadal oscillations during the last century. The wavelet analysis also confirms the prediction of such out-of-phase feature between these two basins, which varied from 0.62 in 1960 to 0.25 in 1995. Furthermore, a coupled ice-ocean general circulation model (GCM) was used to simulate two scenarios, one without the greenhouse gas warming and the other having realistic atmospheric forcing along with the warming that leads to sea-ice reduction trend. The quasi-decadal ASIO is excited in the latter case compared to the no-warming case. The wavelet analyses of the simulated ice volume were also conducted to derive decadal ASIO and similar phase relationship between the Arctic Ocean and the Nordic Seas. An independent data source was used to confirm such decadal oscillation in the upper layer (or freshwater) thickness, which is consistent with the model simulation. A modified feedback loop for the sea-ice trend and ASIO was proposed based on the previous one by Mysak and Venegas and the ice/albedo and cloud/albedo feedabcks, which are responsible for the sea ice reduction trend. 相似文献