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31.
A method for canopy water content estimation for highly vegetated surfaces-shortwave infrared perpendicular water stress index 总被引：7，自引：0，他引：7
In this paper, a new method for canopy water content (FMC) estimation for highly vegetated surfaces- shortwave infrared perpendicular water stress index (SPSI) is developed using NIR, SWIR wavelengths of Enhanced Thematic Mapper Plus (ETM ) on the basis of spectral features and distribution of surface targets with different water conditions in NIR-SWIR spectral space. The developed method is further explored with radiative transfer simulations using PROSPECT, Lillesaeter, SailH and 6S. It is evident from the results of validation derived from satellite synchronous field measurements that SPSI is highly correlated with FMC, coefficient of determination (R squared) and root mean square error are 0.79 and 26.41%. The paper concludes that SPSI has a potential in vegetation water content estimation in terms of FMC. 相似文献
32.
绿洲—荒漠交错带地下水位分布的遥感模型研究 总被引：16，自引：0，他引：16
以利用卫星遥感数据评价干旱区绿洲－荒漠交错带地下水位的分布作为主要研究目的，使用波段Landsat-7ETM 图像，用遥感－数学－模型学融合的研究方法，在实地考察地下水位，土壤水分和其他辅助资料的基础上，建立土壤水分和地下水位的实验方程，提出了评价地下水位分布的遥感模型－GLDRS模型。利用GLDRS模型对新疆策勒绿洲－荒漠交错带进行了实地验证，结果表明，研究结果符合实际，GLDRS多波段模型优越单波段模型，理论地下水位和实测地下水位之间的相关系数为0．901。 相似文献
33.
In this paper, temporal dynamics of eco-environmental changes in coastal areas of China during 1981–2000 are investigated
based on four key surface parameters including normalized difference vegetation index (NDVI), thermal index, moisture index
and surface broadband albedo derived from quantitative remote sensing techniques and meteorological data. Firstly, land surface
temperature (LST) and land surface broadband albedo are retrieved by the split-window algorithms and high-order polynomial
regression method, respectively, using NOAA/AVHRR series images. Then, moisture index and thermal index, indicators of climate
and moisture conditions in the study area, are computed from meteorological data and LST using principal component analysis
(PCA). Finally, long-term dynamics of these eco-environmental factors and the reasons responsible for these changes are analyzed
further. The results show that during the years from 1981 to 2000, the study area experienced a gradual increase in annual
NDVI and climate factors and a decrease in surface annual broadband albedo, which indicates that the coastal thermal and moisture
conditions and the subsistence conditions of natural vegetation have changed to a considerable extent. According to the results,
a warming and wetting tendency over the last two decades is obvious in the China’s coastal zone that are mainly due to land
use changes as of growing urbanization, exhaust emissions from industries and transportations and, partly global climate change.
Uncontrolled rapid development of the study area may be blamed for these negative changes as a major driving force. The positive
feedback mechanisms between albedo, NDVI and climate factors also partly explain these changes. This study suggests that the
method integrating biophysical parameters retrieved from remote sensed images and meteorologic data provides a novel and feasible
way to monitor large scale eco-environmental changes.
相似文献
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34.
Naveen Hakhoo Bindra Thusu Devleena Mani Ghulam M. Bhat Jonathan Craig Juergen Thurow Mateen Hafiz Sudeep Kanungo Sumita Koul Waquar Ahmed 《Journal of the Geological Society of India》2016,88(6):685-692
The Proterozoic Sirban Limestone Formation (SLFm) crops out as detached allochthons in the northwest Himalaya (Jammu region, India) and has its coeval equivalents laterally disposed in the west in Salt Range, in the northwest in Abbotabad (Pakistan) and in southeast in Himachal Pradesh (India). The oil and gas occurrences have been reported from the Proterozoic successions globally and the hydrocarbon potential of the SLFm cannot be ruled out.The interbedded shales and algal laminated dolostones within the SLFm have yielded microflora comparable to those reported in the North African Neoproterozoic sandstones and the Late Proterozoic carbonates of the giant oil and gas fields of the Siberian Platform. The SLFm contains a rich and diverse biota comprising ~ 10% of the rock volume in thin section. The rich organic assemblage justified a hydrocarbon source potential analysis of the SLFm, tested in this study by Rock Eval (RE) pyrolysis.RE pyrolysis yielded a total organic carbon (TOC) content of 0.02 to 1 wt. % with very low Hydrogen Index (HI) values for the shales and TOC content averaging 0.02 wt. % for the dolostones. The organically lean shales and dolostones exhibit Tmax values indicative of immature to post mature stage. But, since these values are for the samples with complex thermal and tectonic history the results may be unreliable. The highly altered organic matter and kerogen present in the SLFm had the potential to generate hydrocarbons and presently indicates no significant source potential. This study is important for understanding the hydrocarbon occurrences in the SLFm particularly in light of the recent oil and gas discoveries from the coeval Proterozoic successions. 相似文献
35.
Worldwide carbon dioxide emissions continue to increase driven by fossil fuel consumption and industrial discharges. Progress on carbon emission reduction requires firms to adopt clean technologies which minimize material and energy consumption. Technological change is particularly required in developing countries, where industrial emissions often lead to chronic urban pollution problems. In this study, we explore the antecedents of clean technology strategy by firms in developing countries. We combine the contingent natural resource-based view with the relational view to examine how network embeddedness, market incentives and slack resources influence adoption of clean technology. The empirical support for our hypotheses comes from data obtained from 342 firms that operated in the carbon-offset market during the years 2007 to 2009. We find that a firm’s relational network structure influences adoption of clean technologies, particularly when market incentives are low. Contrary to one of the hypotheses, the results of our paper suggest a negative relationship between a firm’s slack resources and its clean technology strategy. Our study highlights the benefits of networks in fostering adoption of clean technology in developing countries. Furthermore, we find that high market incentives (carbon price) decrease the probability of clean technology adoption, so adding to the view that firms respond to carbon-offset rules to realize high carbon revenues at the lowest cost.
Key policy insights
High market incentives (carbon price) decrease the probability that firms in developing countries will adopt clean technology.
This adds to concerns about the capability of the Clean Development Mechanism to deliver sustainable development.
Even where market incentives are low, firms in developing countries are more likely to adopt clean technologies when they are embedded in a closed network of connected partners.
To stimulate adoption of clean technology in developing countries, policy makers should focus on initiatives to facilitate partnerships between organizations operating in the carbon market and create opportunities for knowledge sharing and learning.
By changing the policy focus to networks of organizations, the carbon market can bring about positive change in terms of shifting the firm behaviour.
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新疆艾比湖流域地表水丰水期和枯水期水质分异特征及污染源解析 总被引：1，自引：0，他引：1
采用2015年艾比湖流域54个采样点的10个地表水水质指标数据,首先利用水质指数模型(WQI)和地统计学方法对流域水质污染情况进行全局评价,然后利用层次聚类法、判别分析法和因子分析法分析艾比湖流域地表水丰水期和枯水期水质分异特征.在水质时空分异特征研究的基础上,利用主成分回归分析法对艾比湖流域水质进行污染源解析.结果表明:艾比湖流域丰水期WQI值介于38~70之间,枯水期WQI值介于31~71之间,艾比湖流域丰水期的地表水水质污染情况比枯水期严重,而艾比湖、博尔塔拉河和精河靠近艾比湖湖区的河道污染程度均比其他河道严重.由聚类分析和判别分析得出艾比湖流域丰水期和枯水期的水质采样点在空间上均被分成A、B两组,A组包括艾比湖湖区西部、奎屯河、古尔图河和四棵树河,B组包括艾比湖湖区东部、精河和博尔塔拉河.艾比湖流域丰水期和枯水期的水体主要受到化学需氧量、溶解氧、氨氮和悬浮物浓度等指标的影响,B组水质污染指标的值相比于A组的值偏高,B组区域内存在高污染企业,艾比湖流域水环境治理工作需主要集中在B组所包括的艾比湖湖区、博尔塔拉河和精河.(4)艾比湖湖区、精河和博尔塔拉河地表水体的污染主要来自于有机物污染和营养物质污染,其次为工矿业污染;而奎屯河、古尔图河、四棵树河地表水体的污染主要来自于有机物污染,其次为营养物质污染,生物污染的影响较为微弱.该研究结果可为艾比湖流域地表水水环境改善和治理提供一定参考. 相似文献
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Jianfan Sun Qaiser Javed Ahmad Azeem Muhammad Saif Ullah Ghulam Rasool Daolin Du 《洁净——土壤、空气、水》2020,48(9)
Coordination of plant functional traits with changes in the environment is helpful to understand the mechanisms underlying both invasiveness and adaptation of plants. Thus, to investigate the performance and functional traits in invasive Alternanthera philoxeroides (Mart.), an experiment of water stress is conducted with different nutrient concentrations. Alternanthera philoxeroides plants are grown under natural and nutrient soils and subjected to three levels of nitrogen (N) and phosphorus (P) solution: ambient P and N concentration (P?N?), P addition with an ambient N concentration (P+N?), and P addition with high N concentration (P+N+) in combination with three different irrigation water levels as 1) 100% irrigation, 2) 50% irrigation, and 3) 25% deficit irrigation. Based on results, A. philoxeroides produces significantly higher biomass in both soils under 100% irrigation with P+N? treatment and exhibits higher values of leaf area and root length. However, 25% irrigation with P?N? treatment in both soils exerts a significant negative effect on relative growth rate and root/shoot ratio of A. philoxeroides plants. Under 50% irrigation in soils with both P+N? and P+N+ treatments, high values of leaf nitrogen are recorded. Moreover, nutrient soil is more supportive to A. philoxeroides than natural soil. 相似文献
40.
Ghulam RASUL Qamar-uz-Zaman CHAUDHRY ZHAO Sixiong ZENG Qingcun QI Linlin ZHANG Gaoying 《大气科学进展》2005,22(3):375-391
This paper presents the results of a diagnostic study of a typical case of very heavy rainfall during the South Asian summer monsoon when a mesoscale low in a desert climate merged with a diffused tropical depression. The former low was located over Pakistan‘s desert region and the latter depression originated over the Bay of Bengal. Surface and NCEP reanalysis data supported by satellite and radar images were incorporated in the diagnosis. The relationship between the heavy precipitation process and large-scale circulations such as monsoon trough, subtropical high, westerly jet, low level jet and water vapor transport were investigated to further understand the mechanism of this peculiar interaction. It was found that: (1) the mesoscale low developed as a result of cold air advection aloft from northern latitudes and strong convection over the region of humidity convergence on 24 July 2003 over the lndian Rajistan area. (2) On the same day, a low that formed over the Bay of Bengal was transformed into a monsoon depression and moved westward to the mesoscale low which existed over southwest India and the adjoining southeastern parts of Pakistan. (3) Initially, the mesoscale low received moisture supply from both the Bay of Bengal as well as the Arabian Sea, whereas the Bay of Bengal maintained the continuous supply of moisture to the monsoon depression. (4) After the depression crossed central India, the Bay‘s moisture supply was cut off and the Arabian Sea became the only source of moisture to both the closely located systems. On 27 July, both of the systems merged together and the merger resulted in a heavy downpour in the Karachi metropolitan and in its surroundings. (5) With the intensification as well as the southeastward extensionof the subtropical high and the shift of the monsoon trough axis from southwest-west to northeast-east,the monsoon depression moved southwestward. In this situation, there existed a very favourable condition for a merger of the two systems in the presence of cross-latitude influence. (6) A number of convective cloud clusters were developed and organized in the mesoscale low. Probably, interactions existed among the multi-scale systems. 相似文献