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401.
M. Capobianco M. J. F. Stive J. A. Jiménez A. Sanchez-Arcilla 《Journal of Coastal Conservation》1998,4(1):7-16
Global climatic change is likely to take place and could eventually affect Mediterranean deltas and other lowlying coastal
regions. This would have serious implications for the natural resources of these deltaic areas, as well as for human settlements
and related economic activities.
To achieve sound decision making, to prevent damages and to avoid risky investments, it is necessary to understand the integral
functioning of deltaic areas and to determine their vulnerability and response to large-scale change phenomena. Optimal use
of the available knowledge will require that existing and new field measurements are combined and that integrated (physical/ecological)
conceptual models of deltaic behaviour are developed with socio-economics scenarios as boundary conditions.
This paper illustrates the methodological effort towards organizing a modeling framework to conduct budget computations at
various scales with reference to the most significant ‘physiogrpahic units’ and to the most significant deltaic processes.
The final objective is to handle the problem of evaluating possible changes under different scenarios. 相似文献
402.
Kalikhman I 《Environmental monitoring and assessment》2007,129(1-3):197-206
A mathematical model is used to examine the effects of choosing various units of sampling distance of a spiral acoustic survey
on the adequacy of reconstructing patchy distribution fields. The model simulates fish or plankton patches (or gaps) of different
shapes and spatial orientations, and an acoustic survey by a spiral of Archimedes along which a unit of sampling distance
is set. For comparison, surveys are imitated by parallel transects along which the same unit of sampling distance is set.
Adequacy of the reconstructed fields to those originally generated is evaluated by calculating their correlations (r). In the case of a spiral survey, the mathematical experiments conducted show that an immovable field can be reconstructed
properly (r
2 > 0.70) if the ratio of the units of sampling distance to the autocorrelation radius for the field averaged in various directions
d/R
av < 1.0–1.5. Regarding immovable fields, the spiral surveys ensure, practically speaking, the same adequacy of the field reconstruction
as do surveys by parallel transects with the same unit of sampling distance. In regard to movable fields, a comparison of
the results of spiral surveys with those of surveys by parallel transects indicates that the former may ensure even higher
adequacy of the field reconstruction than do the latter, provided that the units of sampling distances in these surveys are
equal to each other. 相似文献
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