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941.
Climate adaptation is uniquely linked to location, making it predominantly a local government and community responsibility. Despite the obligation to act, local governments are hindered by the absence of applicable guides to adaptation decision-making, especially adaptation to extreme events. In this paper, we describe a framework for prioritising adaptation options that could be locally implemented and illustrate it with a study of flooding in Kochi: a city in southern India. Unlike many demand driven, economics based studies, our new framework also incorporates non-economic dimensions of the extremes and potential adaptation options. Local knowledge is used to tackle data gaps and uncertainty related to extreme events: local experts select adaptation options that offer additional benefits besides those related to climate change. These co-benefits aid decision making under uncertainty by giving weight to community priorities. The Indian case study reveals that, risk evaluation and reduction need to be locally contextualised based on resources available, immediate community requirements, planning periods and local expert knowledge. Although there will be residual damage even after implementing selected options, we argue that, climate response will be most likely to be accepted when it also supports pressing needs. 相似文献
942.
943.
Christian Haas John Lobach Stefan Hendricks Lasse Rabenstein Andreas Pfaffling 《Journal of Applied Geophysics》2009,67(3):234-241
Sea ice is an important climate variable and is also an obstacle for marine operations in polar regions. We have developed a small and lightweight, digitally operated frequency-domain electromagnetic-induction (EM) system, a so-called EM bird, dedicated for measurements of sea ice thickness. It is 3.5 m long and weighs only 105 kg, and can therefore easily be shipped to remote places and operated from icebreakers and small helicopters. Here, we describe the technical design of the bird operating at two frequencies of f1 = 3.68 kHz and f2 = 112 kHz, and study its technical performance. On average, noise amounts to ± 8.5 ppm and ± 17.5 ppm for f1 and f2, respectively. Electrical drift amounts to 200 ppm/h and 2000 ppm/h for f1 and f2, during the first 0.5 h of operation. It is reduced by 75% after 2 h. Calibration of the Inphase and Quadrature ppm signals varies by 2 to 3%. A sensitivity study shows that all these signal variations do affect the accuracy of the ice thickness retrieval, but that it remains better than ± 0.1 m over level ice in most cases. This accuracy is also confirmed by means of comparisons of the helicopter EM data with other thickness measurements. The paper also presents the ice thickness retrieval from single-component Inphase data of f1. 相似文献
944.
Stefan Hastenrath 《Quaternary Science Reviews》2009,28(9-10):790-798
Tropical glaciers are considered along three meridional profiles, for the Australasian sector, Africa and the Americas. Evaluated are the annual mean freezing level 0 °C, modern equilibrium line altitude MEL, and past equilibrium line altitude PEL. The calculation of 0 °C is based on a 1958–1997 global data set; MEL refers to estimates concerning the first half of the 20th century; and the timing of the PEL is not generally known. 0 °C stands around 4000–5000 m, with lower levels in the outer tropics. MEL is reached in the Australasian sector on four mountains, and in Africa on three mountains, near the Equator, near or above 0 °C. In the American cordilleras many peaks are still glaciated, above 0 °C, but in the arid southern tropical Andes even summits above 6000 m do not reach MEL. The PEL stands between 3000 m and 5000 m, high in the equatorial zone, but highest in the arid southern tropical Andes. The height difference between MEL and PEL is of order 1000 m, with regional differences. Deglaciation dates range between 15,000 and 8000 years BP, with later timing towards the higher elevations. This synopsis suggests priority targets for further research: morphological mapping and age determination in the High Atlas of Morocco; timing of deglaciation in the High Semyen of Ethiopia and the Altos de Cuchumatanes of Guatemala; exploration in the highlands of Lesotho and of the Dominican Republic; and glaciation in the arid southern tropical Andes. 相似文献
945.
Stefan Gelcich Omar Defeo Oscar Iribarne Graciano Del Carpio Random DuBois Sebastian Horta Juan Pablo Isacch Natalio Godoy Pastor Coayla Pealoza Juan Carlos Castilla 《Marine Policy》2009,33(5):801-806
Ecosystem-based management (EBM) has recently received considerable attention. However, examples of empirical approaches to marine EBM are scarce. Therefore, empirical information on the presence of EBM elements within existing policies and the way they may provide settings and lessons for EBM implementation is timely. This study analyses stakeholders’ perceptions on the existence of EBM principles in current marine management practices and policies, and how they determine perceptions for success and satisfaction regarding coastal management within selected case studies drawn from four developing countries in the Southern Cone of South America. Patterns of response across study sites show that although EBM principles as such are not explicitly included in management/conservation plans, there are policies (mainly local), which generate conditions for more explicit inclusion of them. These are based on participatory bottom-up planning, place-based management and consensus reaching: all elements included within the theoretical literature on EBM implementation. 相似文献
946.
GNSS processing at CODE: status report 总被引:26,自引:19,他引:7
Rolf Dach Elmar Brockmann Stefan Schaer Gerhard Beutler Michael Meindl Lars Prange Heike Bock Adrian Jäggi Luca Ostini 《Journal of Geodesy》2009,83(3-4):353-365
Since May 2003, the Center for Orbit Determination in Europe (CODE), one of the analysis centers of the International GNSS Service, has generated GPS and GLONASS products in a rigorous combined multi-system processing scheme, which promises the best possible consistency of the orbits of both systems. The resulting products, in particular the satellite orbits and clocks, are easily accessible by the user community. In the first part of this article, we focus on the generation of the combined global products at CODE, where we put emphasis not only on accuracy, but also on completeness. We study the impact of GLONASS on the CODE products, and the benefit of using them. Last, but not least, we introduce AGNES (Automated GNSS Network for Switzerland), a regional tracking network of small extensions (roughly 400 km East–West, 200 km North–South), which consequently tracks all GNSS satellites and analyzes their measurements using the CODE products. 相似文献
947.
In this paper a MATLAB toolbox for determining the attitude of a rigid platform by means of multiple non-dedicated antennas
using global positioning system is presented. The programs embedded in this toolbox cover the RINEX data analysis, single
point positioning, differential positioning, coordinate conversion, attitude determination, and other auxiliary functions.
After forming the baselines through double-differenced (carrier phase smoothed) code observables, the attitude parameters
are obtained by applying the direct attitude computation and the least squares attitude estimation. The theoretical background
is summarized, and some hints regarding the software implementation are given in the paper. Moreover, improvements yielding
an expanded functionality are proposed.
相似文献
Zhen DaiEmail: |
948.
During deteriorated prey availability, purely pelagic, specialised seabird species have to alter their feeding strategy by extending foraging radii and/or time spent at sea or reducing feeding intervals of chicks. In contrast, more generalised species such as the opportunistic black-headed gull (Larus ridibundus) breeding at the German North Sea coast, can be assumed to react on prey shortages by switching foraging habitats. The coastal zone of the German North Sea provides a rich habitat mosaic consisting of the offshore zone, tidal flats and terrestrial habitats. Thus, we expected distinct temporal and spatial patterns of habitat switch in accordance with prey availability and environmental constraints. We carried out ship-based and aerial surveys as well as dietary analyses and observations on flight activity. We found a significant switch from terrestrial to marine feeding sites both on a daily basis (related to tidal cycle) and over the whole breeding season. Most likely, the latter switch is the result of lower prey availability in the terrestrial habitats and an increasing quality (in terms of prey abundance and energy intake) of the marine area. While there was only moderate variability in habitat use among different years, we revealed significant differences in the diet of birds from different colonies. The high dietary plasticity and flexible feeding strategy, switching between terrestrial and marine prey is certainly of major importance for the success of an opportunistic avian top predator in a complex coastal zone. It is suggested that – compared to situations elsewhere – the number of breeding pairs of black-headed gulls in the German North Sea coast are still stable due to the switch of foraging habitats performed by individuals in this region. 相似文献
949.
950.
Structural uplift and ejecta thickness of lunar mare craters: New insights into the formation of complex crater rims
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We investigate the elevated crater rims of lunar craters. The two main contributors to this elevation are a structural uplift of the preimpact bedrock and the emplacement of ejecta on top of the crater rim. Here, we focus on five lunar complex mare craters with diameters ranging between 16 and 45 km: Bessel, Euler, Kepler, Harpalus, and Bürg. We performed 5281 measurements to calculate precise values for the structural rim uplift and the ejecta thickness at the elevated crater rim. The average structural rim uplift for these five craters amounts to SRU = 70.6 ± 1.8%, whereas the ejecta thickness amounts to ET = 29.4 ± 1.8% of the total crater rim elevation. Erosion is capable of modifying the ratio of ejecta thickness to structural rim uplift. However, to minimize the impact of erosion, the five investigated craters are young, pristine craters with mostly preserved ejecta blankets. To quantify how strongly craters were enlarged by crater modification processes, we reconstructed the dimensions of the transient crater. The difference between the transient crater diameter and the final crater diameter can extend up to 11 km. We propose reverse faulting and thrusting at the final crater rim to be one of the main contributing factors of forming the elevated crater rim. 相似文献