GEOTHERMICS GEOLOGY     

《Abstract of Chinese Geological Literature》2014,(2)

正20140958 Mei Huicheng(No.915GeologicalBrigade,Jiangxi Bureau of Geology and Mineral Resources,Nanchang 330002,China);Li Zhongshe Geological Features and Causes of the Huihuang Geotherm in Xiushui,Jiangxi Province(Journal of Geological Hazards and  相似文献   

The role of ground reference data collection in the prediction of stem volume with LiDAR data in mountain areas     

Michele Dalponte  Cristina Martinez  Mirco Rodeghiero  Damiano Gianelle 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(6):787-797

Ground reference data collection represents an important element in the prediction of stem volume with LiDAR-derived variables, and at present it is the most expensive part of such analyses. In this paper two aspects of ground reference data collection were analyzed: (1) the positioning error of the ground plots; and (2) the optimal number of training plots. A system for the prediction of stem volume at area-based level was adopted. LiDAR data were preprocessed and 13 variables describing both height and coverage were extracted. Models were defined using a stepwise ordinary least square (OLS) regression. Three experiments were conducted: (i) the role of the plots positioning error on prediction accuracy; (ii) the influence of random downsampling of plot numbers on prediction accuracy; and (iii) the influence of a stratified downsampling of plot numbers on prediction accuracy based on LiDAR-derived variables. A dataset comprising 799 ground plots was used. They were distributed throughout a mountainous area in the Southern Alps, where the presence of a complex landscape increases the uncertainty of the Global Positioning System (GPS) accuracy, and where a large variety of tree forest species and climatic environments make it necessary to have a large number of sample plots for accurate characterization of the study area. All the experiments provided important indications for LiDAR based forest inventories: the GPS error did not significantly influence the prediction accuracy and it was possible to reduce the number of training samples without compromising the generalization ability of the prediction model. Leading on from these findings, a new ground sampling protocol based on genetic algorithms was proposed. The new protocol allowed us to obtain promising results for the considered dataset: using only 53 training plots, instead of 534 in the original dataset, we obtained the same results for the validation set. These results, obtained in a complex mountainous area, are representative of Alpine environments and allow us to infer that similar (or better) results could also be obtained within non mountainous areas.  相似文献   

Land-cover change in the conterminous United States from 1973 to 2000   总被引：1，自引：0，他引：1  

Benjamin M. Sleeter  Terry L. Sohl  Thomas R. Loveland  Roger F. Auch  William Acevedo  Mark A. Drummond  Kristi L. Sayler  Stephen V. Stehman 《Global Environmental Change》2013,23(4):733-748

Land-cover change in the conterminous United States was quantified by interpreting change from satellite imagery for a sample stratified by 84 ecoregions. Gross and net changes between 11 land-cover classes were estimated for 5 dates of Landsat imagery (1973, 1980, 1986, 1992, and 2000). An estimated 673,000 km²(8.6%) of the United States’ land area experienced a change in land cover at least one time during the study period. Forest cover experienced the largest net decline of any class with 97,000 km² lost between 1973 and 2000. The large decline in forest cover was prominent in the two regions with the highest percent of overall change, the Marine West Coast Forests (24.5% of the region experienced a change in at least one time period) and the Eastern Temperate Forests (11.4% of the region with at least one change). Agriculture declined by approximately 90,000 km² with the largest annual net loss of 12,000 km² yr^?1 occurring between 1986 and 1992. Developed area increased by 33% and with the rate of conversion to developed accelerating rate over time. The time interval with the highest annual rate of change of 47,000 km² yr^?1 (0.6% per year) was 1986–1992. This national synthesis documents a spatially and temporally dynamic era of land change between 1973 and 2000. These results quantify land change based on a nationally consistent monitoring protocol and contribute fundamental estimates critical to developing understanding of the causes and consequences of land change in the conterminous United States.  相似文献   

A spatial approach to baseline and leakage in CDM forest carbon sinks projects     

Michael Dutschke  Sonja Butzengeiger  Axel Michaelowa 《Climate Policy》2013,13(5):517-530

Abstract

Forestry projects under the Clean Development Mechanism (CDM) face specific challenges with regard to determination of a baseline for carbon sequestration. We propose a semi-standardized approach called PARAPIA for calculation of a baseline that is built on the concept of a reference area around the project area whose land-use characteristics determine the baseline scenario. The land-use shares in the reference area are checked at each verification. Baseline carbon stocks are then derived ex post using the average carbon content of each land-use type. The reference area is between five and ten times larger than the project area. To determine indirect effects (the so-called ‘leakage’), a political influence area such as province or state is assessed with regards to migration flows due to the project and related emissions.  相似文献   

Economics of climate change mitigation forest policy scenarios for Ukraine   总被引：1，自引：0，他引：1  

Maria Nijnik 《Climate Policy》2013,13(3):319-336

Abstract

This article reveals the contribution of woodland expansion in Ukraine to climate change mitigation policies. The opportunities for climate change mitigation of three policy scenarios: (1) carbon storage in forests, (2) carbon storage and additional wood-for-fuel substitution, and (3) carbon storage with additional sink policy for wood products, are investigated by using a simulation technique, in combination with cost—benefit analysis. The article concludes that the Ukraine's forests and their expansion offer a low-cost opportunity for carbon sequestration. Important factors that influence the results are the discount rate and the time horizon considered in the models. The findings provide evidence that the storage climate change mitigation forest policy scenario is most viable for the country, under the assumptions considered in this research.  相似文献   

Linkages between climate change and sustainable development     

《Climate Policy》2013,13(2-3):129-144

Abstract

Climate change does not yet feature prominently within the environmental or economic policy agendas of developing countries. Yet evidence shows that some of the most adverse effects of climate change will be in developing countries, where populations are most vulnerable and least likely to easily adapt to climate change, and that climate change will affect the potential for development in these countries. Some synergies already exist between climate change policies and the sustainable development agenda in developing countries, such as energy efficiency, renewable energy, transport and sustainable land-use policies. Despite limited attention from policy-makers to date, climate change policies could have significant ancillary benefits for the local environment. The reverse is also true as local and national policies to address congestion, air quality, access to energy services and energy diversity may also limit GHG emissions. Nevertheless there could be significant trade-offs associated with deeper levels of mitigation in some countries, for example where developing countries are dependent on indigenous coal and may be required to switch to cleaner yet more expensive fuels to limit emissions. The distributional impacts of such policies are an important determinant of their feasibility and need to be considered up-front. It follows that future agreements on mitigation and adaptation under the convention will need to recognise the diverse situations of developing countries with respect to their level of economic development, their vulnerability to climate change and their ability to adapt or mitigate. Recognition of how climate change is likely to influence other development priorities may be a first step toward building cost-effective strategies and integrated, institutional capacity in developing countries to respond to climate change. Opportunities may also exist in developing countries to use regional economic organisations to assist in the design of integrated responses and to exploit synergies between climate change and other policies such as those designed to combat desertification and preserve biodiversity.

© 2002 Elsevier Science Ltd. All rights reserved.  相似文献   

Above ground biomass estimation in an African tropical forest with lidar and hyperspectral data     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

The estimation of above ground biomass in forests is critical for carbon cycle modeling and climate change mitigation programs. Small footprint lidar provides accurate biomass estimates, but its application in tropical forests has been limited, particularly in Africa. Hyperspectral data record canopy spectral information that is potentially related to forest biomass. To assess lidar ability to retrieve biomass in an African forest and the usefulness of including hyperspectral information, we modeled biomass using small footprint lidar metrics as well as airborne hyperspectral bands and derived vegetation indexes. Partial Least Square Regression (PLSR) was adopted to cope with multiple inputs and multicollinearity issues; the Variable of Importance in the Projection was calculated to evaluate importance of individual predictors for biomass. Our findings showed that the integration of hyperspectral bands (R² = 0.70) improved the model based on lidar alone (R² = 0.64), this encouraging result call for additional research to clarify the possible role of hyperspectral data in tropical regions. Replacing the hyperspectral bands with vegetation indexes resulted in a smaller improvement (R² = 0.67). Hyperspectral bands had limited predictive power (R² = 0.36) when used alone. This analysis proves the efficiency of using PLSR with small-footprint lidar and high resolution hyperspectral data in tropical forests for biomass estimation. Results also suggest that high quality ground truth data is crucial for lidar-based AGB estimates in tropical African forests, especially if airborne lidar is used as an intermediate step of upscaling field-measured AGB to a larger area.  相似文献   

A hybrid framework for single tree detection from airborne laser scanning data: A case study in temperate mature coniferous forests in Ontario,Canada     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

This study presents a hybrid framework for single tree detection from airborne laser scanning (ALS) data by integrating low-level image processing techniques into a high-level probabilistic framework. The proposed approach modeled tree crowns in a forest plot as a configuration of circular objects. We took advantage of low-level image processing techniques to generate candidate configurations from the canopy height model (CHM): the treetop positions were sampled within the over-extracted local maxima via local maxima filtering, and the crown sizes were derived from marker-controlled watershed segmentation using corresponding treetops as markers. The configuration containing the best possible set of detected tree objects was estimated by a global optimization solver. To achieve this, we introduced a Gibbs energy, which contains a data term that judges the fitness of the objects with respect to the data, and a prior term that prevents severe overlapping between tree crowns on the configuration space. The energy was then embedded into a Markov Chain Monte Carlo (MCMC) dynamics coupled with a simulated annealing to find its global minimum. In this research, we also proposed a Monte Carlo-based sampling method for parameter estimation. We tested the method on a temperate mature coniferous forest in Ontario, Canada and also on simulated coniferous forest plots with different degrees of crown overlap. The experimental results showed the effectiveness of our proposed method, which was capable of reducing the commission errors produced by local maxima filtering, thus increasing the overall detection accuracy by approximately 10% on all of the datasets.  相似文献   

A possible satellite of (146) Lucina     

J.E. Arlot  J. Lecacheux  Ch. Richardson  W. Thuillot 《Icarus》1985,61(2):224-231

This paper reports on an observation of the appulse of (146) Lucina with AGK3 + 17° 1309 made on April 18, 1982, at the Meudon Observatory in France. During this observation a secondary event occurred and was recorded. A Nocticon camera mounted on the 1-m telescope and video equipment was used. This equipment is well adapted to these observations primarily because astrometric and photometric reductions are possible. Furthermore no diaphragm is necessary in contrast to classical photometry, and this reduces the possibility of generating artifacts. The Meudon observation is described. Observational data from other sites have been collected, and have confirmed that the short extinction observed at Meudon was not due to the asteroid itself. A possible interpretation is the existence of a faint satellite in the neighborhood of (146) Lucina. The observation leads to a diameter of at least 5.7 km and a projected distance of 1600 km from the primary.  相似文献   

山东省地震局防震减灾信息网发展现状和趋势   总被引：1，自引：0，他引：1  

李红 《国际地震动态》2001,(10):20-22

系统地介绍了山东省地震局在防震减灾信息网站建设方面所取得的一些进展 ;结合我国防震减灾信息网的现状 ,提出了在网络环境下 ,网站信息服务的发展方向。  相似文献