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21.
Tracing glacier wastage in the Northern Tien Shan (Kyrgyzstan/Central Asia) over the last 40 years 总被引：2，自引：1，他引：1
Peter Niederer Viktor Bilenko Natasha Ershova Hans Hurni Sergeji Yerokhin Daniel Maselli 《Climatic change》2008,86(1-2):227-234
The status and dynamics of glaciers are crucial for agriculture in semiarid parts of Central Asia, since river flow is characterized
by major runoff in spring and summer, supplied by glacier- and snowmelt. Ideally, this coincides with the critical period
of water demand for irrigation. The present study shows a clear trend in glacier retreat between 1963 and 2000 in the Sokoluk
watershed, a catchment of the Northern Tien Shan mountain range in Kyrgyzstan. The overall area loss of 28% observed for the
period 1963–2000, and a clear acceleration of wastage since the 1980s, correlate with the results of previous studies in other
regions of the Tien Shan as well as the Alps. In particular, glaciers smaller than 0.5 km2 have exhibited this phenomenon most starkly. While they registered a medium decrease of only 9.1% for 1963–1986, they lost
41.5% of their surface area between 1986 and 2000. Furthermore, a general increase in the minimum glacier elevation of 78 m
has been observed over the last three decades. This corresponds to about one-third of the entire retreat of the minimum glacier
elevation in the Northern Tien Shan since the Little Ice Age maximum. 相似文献
22.
<正> 森林提供许多有价值的生态服务,诸如保护流域和生物多样性以及贮存碳素等,现已引起企业、政府乃至个人越来越多的关注,同时人们也意识到随着森林这些功能的退化甚至丧失所带来的危险和代价。这种退化既能引起洪水、山崩之类的局部灾难,也会导致全球气候变化之类的广泛影响。 相似文献
23.
Mental preparation for climate adaptation: The role of cognition and culture in enhancing adaptive capacity of water management in Kiribati 总被引：3，自引：0，他引：3
Natasha KuruppuAuthor Vitae Diana LivermanAuthor Vitae 《Global Environmental Change》2011,21(2):657-669
In many Least Developed Countries (LDCs) and Small Island Developing States (SIDS), such as in Kiribati, formal national adaptation programmes are currently being operationalised or are in the pipeline. A key focus is on motivating householders to adapt in anticipation of climate change through pilot community projects. In this paper, we argue that the water sector must pay equal attention to how communities cognitively perceive the process of adaptation if interventions are to be effective. Adopting a cognitive model to gain such insights we conclude that individual's belief in their own abilities to manage water stress play a crucial role in driving intentions to adapt and therefore greater attention needs to be placed on understanding the underling drivers shaping such beliefs. 相似文献
24.
Biomass allometric equation and expansion factor for a mountain moist evergreen forest in Mozambique
Sá Nogueira Lisboa Benard Soares Guedes Natasha Ribeiro Almeida Sitoe 《Carbon balance and management》2018,13(1):23
Background
Worldwide, forests are an important carbon sink and thus are key to mitigate the effects of climate change. Mountain moist evergreen forests in Mozambique are threatened by agricultural expansion, uncontrolled logging, and firewood collection, thus compromising their role in carbon sequestration. There is lack of local tools for above-ground biomass (AGB) estimation of mountain moist evergreen forest, hence carbon emissions from deforestation and forest degradation are not adequately known. This study aimed to develop biomass allometric equations (BAE) and biomass expansion factor (BEF) for the estimation of total above-ground carbon stock in mountain moist evergreen forest.Methods
The destructive method was used, whereby 39 trees were felled and measured for diameter at breast height (DBH), total height and the commercial height. We determined the wood basic density, the total dry weight and merchantable timber volume by Smalian’s formula. Six biomass allometric models were fitted using non-linear least square regression. The BEF was determined based on the relationship between bole stem dry weight and total dry weight of the tree. To estimate the mean AGB of the forest, a forest inventory was conducted using 27 temporary square plots. The applicability of Marzoli’s volume equation was compared with Smalian’s volume equation in order to check whether Marzoli’s volume from national forest inventory can be used to predict AGB using BEF.Results
The best model was the power model with only DBH as predictor variable, which provided an estimated mean AGB of 291?±?141 Mg ha?1 (mean?±?95% confidence level). The mean wood basic density of sampled trees was 0.715?±?0.182 g cm?3. The average BEF was of 2.05?±?0.15 and the estimated mean AGB of 387?±?126 Mg ha?1. The BAE from miombo woodland within the vicinity of the study area underestimates the AGB for all sampled trees. Chave et al.’s pantropical equation of moist forest did not fit to the Moribane Forest Reserve, while Brown’s equation of moist forest had a good fit to the Moribane Forest Reserve, having generated 1.2% of bias, very close to that generated by the selected model of this study. BEF showed to be reliable when combined with stand mean volume from Marzoli’s National Forestry Inventory equation.Conclusion
The BAE and the BEF function developed in this study can be used to estimate the AGB of the mountain moist evergreen forests at Moribane Forest Reserve in Mozambique. However, the use of the biomass allometric model should be preferable when DBH information is available.25.
Fiona J. Valesini Mathew Hourston Michelle D. Wildsmith Natasha J. Coen Ian C. Potter 《Estuarine, Coastal and Shelf Science》2010
This study has developed quantitative approaches for firstly classifying local-scale nearshore habitats in an estuary and then predicting the habitat of any nearshore site in that system. Both approaches employ measurements for a suite of enduring environmental criteria that are biologically relevant and can be easily derived from readily available maps. While the approaches were developed for south-western Australian estuaries, with a focus here on the Swan and Peel-Harvey, they can easily be tailored to any system. 相似文献
26.
Alan J. Hewitt Natasha Doss Nikolai F. Zobov Oleg L. Polyansky Jonathan Tennyson † 《Monthly notices of the Royal Astronomical Society》2005,356(3):1123-1126
HDO and D2 O are thought to be present in significant quantities in the coldest regions of the Universe. Partition functions are calculated for these species and used to calculate temperature dependent equilibrium constants for the most important fractionation reactions involving water. HDO may also be a key indicator of the absence of deuterium burning in very low mass stars. The HDO partition function calculation is extended to high ( T ≤ 6000 K) temperatures for this purpose. 相似文献
27.
28.
The Tortonian–Calabrian strata of Offshore Makran(Pakistan) is investigated for the purpose of reservoir assessment. The stratigraphy and petrophysics indicate that the Neogene sediments have tight reservoir potential with porosities in the range of 3%–9% and 40%–50% water saturation. The mineralogical cross plots indicate a mixed lithology with an abundance of dolomite and calcite, together with minor quartz content and shale. The seismic interpretation demonstrates medium–high amplitude reflec... 相似文献
29.
Avalanche hazard mapping over large undocumented areas 总被引：3，自引：1，他引：2
An innovative methodology to perform avalanche hazard mapping over large undocumented areas is herewith presented and discussed.
The method combines GIS tools, computational routines, and statistical analysis in order to provide a “semi-automatic” definition
of areas potentially affected by avalanche release and motion. The method includes two main modules. The first module is used
to define zones of potential avalanche release, based on the consolidated relations on slope, morphology, and vegetation.
For each of the identified zones of potential release, a second module, named Avalanche Flow and Run-out Algorithm (AFRA),
provides an automatic definition of the areas potentially affected by avalanche motion and run-out. The definition is generated
by a specifically implemented “flow-routing algorithm” which allows for the determination of flow behaviour in the track and
in the run-out zone. In order to estimate the avalanche outline in the run-out zone, AFRA uses a “run-out cone”, which is
a 3D projection of the angle of reach α. The α-value is evaluated by statistical analysis of historical data regarding extreme
avalanches. Pre- and post-processing of the AFRA input/output data is done in an open source GIS environment (GRASS GIS).
The method requires only a digital terrain model and an indication of the areas covered by forest as input parameters. The
procedure, which allows rapid mapping of large areas, does not in principle require any site-specific historical information.
Furthermore, it has proven to be effective in all cases where a preliminary cost-efficient analysis of the territories potentially
affected by snow avalanche was needed. 相似文献
30.
Natasha M. JOHNSON Jamie E. ELSILA Mickey KOPSTEIN Joseph A. NUTH III 《Meteoritics & planetary science》2012,47(6):1029-1034
Abstract— Fischer‐Tropsch‐type (FTT) reactions have been hypothesized to contribute to the formation of organic compounds in the early solar system, but it has been difficult to identify a signature of such reactions in meteoritic organics. The work reported here examined whether temperature‐dependent carbon isotopic fractionation of FTT reactions might provide such a signature. Analyses of bulk organic deposits resulting from FTT experiments show a slight trend toward lighter carbon isotopic ratios with increasing temperature. It is unlikely, however, that these carbon isotopic signatures could provide definitive provenance for organic compounds in solar system materials produced through FTT reactions, because of the small scale of the observed fractionations and the possibility that signatures from many different temperatures may be present in any specific grain. 相似文献