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11.
Zvi Ben-Avraham Yoram Shoham Eitan Klein Haim Michelson Colette Serruya 《Marine Geophysical Researches》1980,4(3):257-276
A magnetic survey of Lake Kinneret (Sea of Galilee) was conducted on a 1 km grid of north-south and east-west lines. The results indicate that the margins of the lake are associated with large amplitude anomalies, while the centre is quite smooth. The largest anomaly, more than 500 nT, was detected in the vicinity of the entrance of the Jordan River into the lake. Its source is interpreted to be Late Cenozoic basaltic flows. The lake's margins are associated with faults, hot springs and magnetic anomalies. A broad magnetic anomaly trending east-northeast extends from Ginosar Valley into the lake through most of the lake's width. The distribution of basalt flows of different ages and the various structures of the magnetized layers are all contributing to the magnetic anomaly pattern. 相似文献
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Beebe et al. [Beebe, R.F., et al., 1980. Geophys. Res. Lett. 17, 1-4] and Ingersoll et al. [Ingersoll, A.P., et al., 1981. J. Geophys. Res. 86, 8733-8743] used images from Voyagers 1 and 2 to analyze the interaction between zonal winds and eddies in Jupiter's atmosphere. They reported a high positive correlation between Jupiter's eddy momentum flux, , and the variation of zonal velocity with latitude, . This correlation implied a surprisingly high rate of conversion of energy from eddies to zonal flow: , a value more than 10% of Jupiter's thermal flux emission. However, Sromovsky et al. [Sromovsky, L.A., et al., 1982. J. Atmos. Sci. 39, 1413-1432] argued that possible biases in the analysis could have caused an artificially high correlation. In addition, significant differences in the derived eddy flux between datasets put into question the robustness of any one result. We return to this long-standing puzzle using images of Jupiter from the Cassini flyby of December 2000. Our method is similar to previous analyses, but utilizes an automatic feature tracker instead of the human eye. The number of velocity vectors used in this analysis is over 200,000, compared to the 14,000 vectors used by Ingersoll et al. We also find a positive correlation between and and derive a global average power per unit mass, , ranging from . Utilizing Ingersoll et al.'s estimate of the mass per unit area involved in the transport, this would imply a rate of energy conversion of . We discuss the implications of this result and employ several tests to demonstrate its robustness. 相似文献
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Evan A. Howell Colette C. C. Wabnitz John P. Dunne Jeffrey J. Polovina 《Climatic change》2013,119(1):79-93
An existing Ecopath with Ecosim (EwE) model for the Central North Pacific was updated and modified to focus on the area used by the Hawaii-based pelagic longline fishery. The EwE model was combined with output from a coupled NOAA Geophysical Fluid Dynamics Laboratory climate and biogeochemical model to investigate the likely ecosystem impacts of fishing and climate-induced primary productivity changes. Four simulations were conducted based on 2 fishing effort and climate scenarios from 2010 to 2100. Modeled small and large phytoplankton biomass decreased by 10 % and 20 % respectively, resulting in a 10 % decline in the total biomass of all higher trophic level groups combined. Climate impacts also affected the Hawaii longline fishery, with a 25–29 % reduction in modeled target species yield. Climate impacts on the ecosystem and the fishery were partially mitigated by a drop in fishing effort. Scenarios with a 50 % reduction in fishing effort partially restored longline target species yield to current levels, and decreased longline non-target species yield. These model results suggest that a further reduction in fishery landings mortality over time than the 2010 level may be necessary to mitigate climate impacts and help sustain yields of commercially preferred fish species targeted by the Hawaii longline fishery through the 21st century. 相似文献
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Colette C.A. Starheim Christopher Gomez Justin Harrison Claire Kain Nicholas J. Brewer Kirsty Owen Danang Sri Hadmoko Heather Purdie Peyman Zawar‐Reza Ian Owens Patrick Wassmer Franck Lavigne 《New Zealand geographer》2013,69(1):26-38
Previous research on debris‐flow deposit structure typically reports little to no visually discernible stratigraphy. The preliminary findings presented here provide evidence for more complex internal deposit architecture with inverse grading and subunits thought to reflect individual flow surges. Ground‐penetrating radar surveys, geospatial data and field observations are used to describe 10 subunits traceable over the 14 lateral radargrams imaging the lower 38 m of the deposit. Additional subunits are depicted further upslope in a longitudinal transect. As well as demonstrating the need for continued investigation of deposit architecture using non‐traditional techniques, these results may help improve future interpretations of post‐event deposits. 相似文献
17.
George Roff Colette C. C. Wabnitz Alastair R. Harborne Peter J. Mumby 《Marine Ecology》2013,34(4):409-419
Small grazing motile epifaunal invertebrates play an important ecosystem role on coral reefs, influencing both the abundance and composition of macroalgal communities and acting as a key food source for a range of predatory fishes. The first aim of this study was to investigate the associations between motile epifaunal communities and four common macroalgal species (Lobophora variegata, Dictyota divaricata, Microdictyon marinum and Halimeda opuntia) on fore‐reef environments in the Exuma Cays (Bahamas, wider Caribbean). Secondly, we investigated the implications of the well documented rise of Caribbean macroalgal cover on invertebrate densities by surveying sites inside and outside the Exuma Cays Land and Sea Park (ECLSP), where increases in parrotfish grazing intensity inside the marine reserves have led to reductions in macroalgal cover. Therefore, surveys compared similar reefs with significantly different macrolagal cover. Comparisons between macroalgal species revealed a four to fivefold difference in motile epifaunal densities per unit volume of macroalgae. Post‐hoc tests revealed that this difference was significant only for Lobophora, with no difference observed among the other species. As macroalgae provide both a refuge from predation and a food source for grazing epifauna, the higher densities of epifauna observed in Lobophora may be attributed to either refuge from visual predators through morphological features (high cover of overlapping blades close to the substrate) or lack of palatability for parrotfish grazing, providing a more stable refuge. Our results revealed no significant differences in diversity, density or community structure of motile epifauna per unit volume of macroalgae between sites inside and outside the ECLSP. Since canopy height and invertivore biomass did not vary systematically across reserve boundaries, this suggests that algal cover does not affect the density of epifaunal invertebrates. However, areal cover was consistently higher for all macroalgal species at sites outside the ECLSP than those inside the reserve. Therefore, when scaled by aerial cover of macroalgae, total abundance of epifauna was twofold higher outside the ECLSP. We suggest that the increasing abundance of macroalgae on Caribbean reefs may be having dramatic effects on epifaunal invertebrate populations and potentially their ecological functions. 相似文献
18.
As a result of the opening of the borders of the former Soviet Union, Israel has been the destination of numerous immigrants.
This article deals with the impact of immigration between 1989 and 1994, upon three towns in the south of Israel, Be'er Sheva,
Ashkelon and Kiriat Gat. These towns correspond to three socio-economic levels of urban area in the southern region. On the
one hand, the immigrants from the former Soviet Union arrive with specific demands, on the other hand the political, economical
and social context in Israel is very unusual. The sucessful integration of immigrants and the constructive development of
the host country depend on the conformity of these demands and proposals. What the government offers in terms of housing,
reception and employment in each of the three towns plays a key role: the town's social and economical heritage influences
the integration of the new population while at the same time the arrival of a new workforce influences the development of
the local area. Every town wants to grow and reinforce its position in the region, but only the large town, Be'er Sheva, is
able to offer a certain diversity and therefore answers more fully the needs and wants of this new population. Government
decisions and policies are not made to oppose the liberal economic system and to suppress the spacial inequalities despite
some measures aiming at a more equal balance. The importance of heritage and the lack of communal development schemes within
regions together ensure the continuation of qualitative inegalities in the south of Israel and even accentuate the problem.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Maria Bianca Cita Colette Vergnaud-Grazzini Christian Robert Hervé Chamley Neri Ciaranfi Sara d&#x;Onofrio 《Quaternary Research》1977,8(2):205-235
A deep-sea core over 16 m long from the crestal area of the Mediterranean Ridge has been investigated with different techniques, including quantitative micropaleontology, stable isotopes (measured on the epipelagic species Globigerinoides ruber and on the mesopelagic species Globorotalia inflata), and clay mineralogy. The resulting record of climatic fluctuations can be cross correlated to other Mediterranean cores by means of isochronous lithologies (tephra layers and sapropels). The climatic record of the Mediterranean is similar in character, phase, and chronology to the records investigated in the equatorial Pacific and in the Caribbean. Isotope stages 1 to 17 have been recognized. Cyclically repeated stagnant cycles resulting in sapropel deposition complicate both the isotopic and the faunal signal. The isotopic investigations reveal that the temperature change in the surface layers of the eastern Mediterranean was no greater than 8°C in the late “glacial” Pleistocene. The chronostratigraphic and biostratigraphic interpretation of Core KS09 indicate that the mean sedimentation rate was 2.4 cm/1000 years, a value very close to the 2.5 cm/1000 years calculated for the entire Quaternary section at DSDP Site 125, also located in the crestal area of the Mediterranean Ridge in the Ionian Basin. The base of KS09 is likely to be very close to the Brunhes/Matuyama boundary dated at 0.7 my. 相似文献
20.
Laurent Menut Om P. Tripathi Augustin Colette Robert Vautard Emmanouil Flaounas Bertrand Bessagnet 《Climate Dynamics》2013,40(9-10):2515-2533
In order to evaluate the future potential benefits of emission regulation on regional air quality, while taking into account the effects of climate change, off-line air quality projection simulations are driven using weather forcing taken from regional climate models. These regional models are themselves driven by simulations carried out using global climate models (GCM) and economical scenarios. Uncertainties and biases in climate models introduce an additional “climate modeling” source of uncertainty that is to be added to all other types of uncertainties in air quality modeling for policy evaluation. In this article we evaluate the changes in air quality-related weather variables induced by replacing reanalyses-forced by GCM-forced regional climate simulations. As an example we use GCM simulations carried out in the framework of the ERA-interim programme and of the CMIP5 project using the Institut Pierre-Simon Laplace climate model (IPSLcm), driving regional simulations performed in the framework of the EURO-CORDEX programme. In summer, we found compensating deficiencies acting on photochemistry: an overestimation by GCM-driven weather due to a positive bias in short-wave radiation, a negative bias in wind speed, too many stagnant episodes, and a negative temperature bias. In winter, air quality is mostly driven by dispersion, and we could not identify significant differences in either wind or planetary boundary layer height statistics between GCM-driven and reanalyses-driven regional simulations. However, precipitation appears largely overestimated in GCM-driven simulations, which could significantly affect the simulation of aerosol concentrations. The identification of these biases will help interpreting results of future air quality simulations using these data. Despite these, we conclude that the identified differences should not lead to major difficulties in using GCM-driven regional climate simulations for air quality projections. 相似文献