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141.
142.
以中国为研究区域,利用CanMETOP模型模拟了2005年大气中α-六六六(α-HCH)浓度的变化,并分析了东亚夏季风对我国东部地区大气中α-HCH浓度时空分布的影响.模拟结果表明,6月15日-8月15日期间,东北、华北和东南地区的α-HCH平均大气浓度分别为260 pg·m~(-3),74 pg·m~(-3)和41 pg·m~(-3).大气浓度具有明显的时空分布特征,从6月15日在我国东南地区开始出现了较高的大气浓度堆集,6月24日达到最大值(259 pg·m~(-3)).在向我国北部传输过程中,7月1日在东北形成的气旋区域出现最大值(1947pg·m~(-3)).此后,东南地区的大气浓度均处于较低的水平(<50 pg·m~(-3)),而东北地区的大气浓度一直处于100-350 pg·m~(-3)之间的较高水平.分析结果表明,东亚夏季风可以将东南地区大气中的α-HCH传输至东北地区,并在东北区域堆集. 相似文献
143.
Thermodynamics is a powerful tool for the study of system development and has the potential to be applied to studies of ecological complexity. Here, we develop a set of thermodynamic indicators including energy capture and energy dissipation to quantify plant community self-organization. The study ecosystems included a tropical seasonal rainforest, an artificial tropical rainforest, a rubber plantation, and two Chromolaena odorata (L.) R.M. King & H. Robinson communities aged 13 years and 1 year. The communities represent a complexity transect from primary vegetation, to transitional community, economic plantation, and fallows and are typical for Xishuangbanna, southwestern China. The indicators of ecosystem self-organization are sensitive to plant community type and seasonality, and demonstrate that the tropical seasonal rainforest is highly self-organized and plays an important role in local environmental stability via the land surface thermal regulation. The rubber plantation is at a very low level of self-organization as quantified by the thermodynamic indicators, especially during the dry season. The expansion of the area of rubber plantation and shrinkage of tropical seasonal rainforest would likely induce local surface warming and a larger daily temperature range. 相似文献
144.
根据旋风除尘理论及湿式纤维栅除尘理沦,提出了一种旋风-湿式纤维栅除尘器,并对影响其性能(效率、阻力)的有关参数(旋流入口风速、喷水量等)进行了大量实验。实验结果表明,该旋风-湿式纤维栅除尘器不仅性能优良,并对资源回收利用及污物的后处理提供很多便利。 相似文献
145.
目的 对热带海洋环境氯离子开展立体化观测,掌握热带海洋环境下大气氯离子浓度在空间上的分布规律,为海洋大气环境下装备产品和重大工程服役环境研究提供立体化观测数据支撑。方法 在观测海岸线附近科学选点,采用无人机搭载远程控制大气采样器开展大气氯离子浓度立体化观测,对不同空间高度氯离子浓度分布规律进行分析。结果 成功采集万宁某海岸线附近1 km×300 m×100 m区域1 a以上氯离子浓度数据,通过GIS技术分析并建立了氯离子浓度分布三维场,实现了氯离子浓度可视化,并随离海距离、离地高度剖切显示。结论 海南万宁某区域海岸线附近氯离子浓度在冬季最大,夏季最低,且在一定观测范围内,随观测高度增加而先增大、后降低,随离海距离增大而逐渐降低。 相似文献
146.
We used linear and multivariate models to examine the associations between geography, biodiversity, per capita economic output, national spending on conservation, governance, and cultural traits in 55 countries. Cultural traits and social metrics of modernization correlated positively with national spending on conservation. The global distribution of this spending culture was poorly aligned with the distribution of biodiversity. Specifically, biodiversity was greater in the tropics where cultures tended to spend relatively less on conservation and tended to have higher collectivism, formalized and hierarchical leadership, and weaker governance. Consequently, nations lacking social traits frequently associated with modernization, environmentalism, and conservation spending have the largest component of Earth's biodiversity. This has significant implications for setting policies and priorities for resource management given that biological diversity is rapidly disappearing and cultural traits change slowly. Therefore, we suggest natural resource management adapt to and use characteristics of existing social organization rather than wait for or promote social values associated with conservation spending. Supporting biocultural traditions, engaging leaders to increase conservation commitments, cross‐national efforts that complement attributes of cultures, and avoiding interference with nature may work best to conserve nature in collective and hierarchical societies. Spending in modernized nations may be a symbolic response to a symptom of economic development and environmental degradation, and here conservation actions need to ensure that biodiversity is not being lost. 相似文献
147.
Rising temperatures, a widespread consequence of climate change, have been implicated in enigmatic amphibian declines from habitats with little apparent human impact. The pathogenic fungus Batrachochytrium dendrobatidis (Bd), now widespread in Neotropical mountains, may act in synergy with climate change causing collapse in thermally stressed hosts. We measured the thermal tolerance of frogs along a wide elevational gradient in the Tropical Andes, where frog populations have collapsed. We used the difference between critical thermal maximum and the temperature a frog experiences in nature as a measure of tolerance to high temperatures. Temperature tolerance increased as elevation increased, suggesting that frogs at higher elevations may be less sensitive to rising temperatures. We tested the alternative pathogen optimal growth hypothesis that prevalence of the pathogen should decrease as temperatures fall outside the optimal range of pathogen growth. Our infection‐prevalence data supported the pathogen optimal growth hypothesis because we found that prevalence of Bd increased when host temperatures matched its optimal growth range. These findings suggest that rising temperatures may not be the driver of amphibian declines in the eastern slopes of the Andes. Zoonotic outbreaks of Bd are the most parsimonious hypothesis to explain the collapse of montane amphibian faunas; but our results also reveal that lowland tropical amphibians, despite being shielded from Bd by higher temperatures, are vulnerable to climate‐warming stress. Fisiología Termal, Enfermedades y Disminuciones de Anfibios en las Laderas Orientales de los Andes 相似文献
148.
Donald V. Dunlap 《Journal of the American Water Resources Association》1972,8(5):1044-1054
ABSTRACT. This paper describes the meteorological patterns that produced the combination of heavy rains in August 1971 that resulted in record floods in New Jersey. Daily and hourly precipitation data and selected recurrence frequencies of rainfall amounts are tabulated. History of previous heavy rainfalls in New Jersey indicates that occurrences of very heavy rains are frequently associated with tropical disturbances. Flood damages, fatalities, warnings issued and areas of record river stages are summarized. 相似文献
149.
Lasco Rodel D. Pulhin Florencia B. 《Mitigation and Adaptation Strategies for Global Change》2000,5(1):81-97
Tropical forests in countries like thePhilippines are important sources and sinks of carbon(C). The paper analyzes the contribution of Philippineforests in climate change mitigation. Since the 1500s,deforestation of 20.9 M ha (106 ha) of Philippineforests contributed 3.7 Pg (1015 g) of C to theatmosphere of which 2.6 Pg were released this century. At present, forest land uses store 1091 Tg(1012 g) of C and sequester 30.5 Tg C/yr whilereleasing 11.4 Tg C/yr through deforestation andharvesting. In the year 2015, it is expected that thetotal C storage will decline by 8% (1005 Tg) andtotal rate of C sequestration will increase by 17%(35.5 Tg/yr). This trend is due to the decline innatural forest area accompanied by an increase intree plantation area. We have shown that uncertaintyin national C estimates still exists because they arereadily affected by the source of biomass and Cdensity data. Philippine forests can act as C sink by:conserving existing C sinks, expanding C stocks, andsubstituting wood products for fossil fuels. Here weanalyze the possible implications of the provisions ofthe Kyoto Protocol to Philippine forests. Finally, wepresent current research and development efforts ontropical forests and climate change in the Philippinesto improve assessments of their role in the nations Cbudgets. 相似文献
150.
运用计算流体力学软件FLUENT,对旋风除尘器内部流场进行了数值模拟,利用模拟结果对旋风除尘器入口不同位置气流在除尘器顶部的环形空间的轨迹进行了分析研究,探明了气流在环形空间的运动规律和基本特征,阐明了旋风除尘器顶部"尘环"形成的根本原因,指出了粉尘发生短路的原因和多发区域并在此基础上就除尘器的增效问题给出了改进方案. 相似文献