Assessing the impact of Celaque National Park on forest fragmentation in western Honduras     

Jane Southworth  Harini Nagendra  Laura A. Carlson  Catherine Tucker 《Applied geography (Sevenoaks, England)》2004,24(4):303-322

The effectiveness of parks as management regimes is much in debate. This study examines the effect of establishment of the Celaque National Park, Honduras, in 1987, on limiting deforestation through a comparison with the surrounding landscape using remote sensing, GIS and landscape pattern analysis. Pressure on the park region is found to relate spatially to the locations of towns and roads, with increasing deforestation in the landscape surrounding the park. In contrast, the park has been largely successful in maintaining forest cover. Although the extent of change within the park is not pronounced, the pattern of change is. Expansion of agriculture and coffee production have led to increasing pressure on the park boundaries, with as much as 25% of the landscape surrounding the park experiencing land cover change between 1996 and 2000. This has significant implications for the future of the park.  相似文献   

江苏新沂地震台短水准新场地映震能力分析   总被引：2，自引：0，他引：2  

李飞 《山西地震》2002,(3):16-17,21

介绍了江苏新沂地震台短水准新场地的基本情况 ,运用滑动分析和自回归分析法对该台1995年至 1999年的资料进行了分析 ,得出江苏新沂地震台短水准新场地有一定映震能力的结论  相似文献   

Effects of a variety of Indian Ocean surface temperature anomaly patterns on the summer monsoon circulation: Experiments with the NCAR general circulation model     

Warren M. Washington  Robert M. Chervin  G. V. Rao 《Pure and Applied Geophysics》1977,115(5-6):1335-1356

The time mean response of the summer monsoon circulation, as simulated by the 2.5° latitude-longitude resolution, July version of the National Center for Atmospheric Research (NCAR) General Circulation Model (GCM), to a variety of Indian Ocean surface temperature anomaly patterns is examined. In separate experiments, prescribed changes in surface temperature are imposed in the Western Arabian Sea, the Eastern Arbian Sea or the Central Indian Ocean. The influence of these anomaly patterns on the simulated summer monsoon circulation is evaluated in terms of the geographical distribution of the prescribed change response for any field of interest. This response is defined as the grid point difference between a 30-day mean from a prescribed change experiment and the ensemble average of the 30-day means from the control population for which the same set of climatological ocean surface temperatures are used in each simulation. The statistical significance of such a prescribed change response is estimated by relating the normalized response (defined as the ratio of the prescribed change response to the standard deviation of 30-day means as estimated from the finite sample of control cases) to the classical Student'st-statistic. Using this methodology, the most prominent and statistically significant features of the model's response are increased vertical velocity and precipitation over warm anomalies and typically decreased vertical velocity and precipitation in some preferred region adjacent to the prescribed change region. In the case of cold anomalies, these changes are of opposite sign. However, none of the imposed anomaly patterns produces substantial or statistically significant precipitation changes over large areas of the Indian sub-continent. The only evidence of a major nonlocal effect is found in the experiment with a large positive anomaly (+3°C) in the Central Indian Ocean. In this instance, vertical velocity and precipitation are reduced over Malaysia and a large area of the Equatorial Western Pacific Ocean. Thus, while these anomaly experiments produce only a local response (for the most part), it is hoped, as one of the purposes of the planned Monsoon Experiment (MONEX), that the necessary data will be provided to produce detailed empirical evidence on the extent to which Indian Ocean surface temperature anomalies correlate with precipitation anomalies over the Indian subcontinent—a correlation which generally does not appear in these GCM results.The National Center for Atmospheric Research is sponsored by the National Science Foundation  相似文献   

Exploring socio-hydrological determinants of crop yield in under-performing irrigation schemes: pathways for sustainable intensification     

Muhammad Khalifa  Nadir Ahmed Elagib  Bashir Mohammed Ahmed  Lars Ribbe  Karl Schneider 《水文科学杂志》2020,65(Z3):153-168

ABSTRACT

Understanding the human–water–food–climate nexus is central to achieving sustainable intensification (SI) in agriculture. This research uses a socio-hydrological approach to understand the underpinning for implementing SI in the Gezira Irrigation Scheme, Sudan, by integrating vegetation indices derived from remote sensing, ancillary, gridded soil and precipitation data, supplemented by interviews with 393 farmers. The productivity gap was estimated as the difference between the potential and actual productivities. Based upon data on farmers’ socio-economic status and field practices, a regression tree model was built to determine the factors that control the sorghum yield. The model revealed that the financial status of farmers and access to water are the most influential factors on sorghum yield. A conceptual framework that elucidates SI and its bi-directional feedback to the environment, society and the economy is proposed. Implementing SI in the scheme has implications on water and food security in Sudan and beyond its borders.  相似文献   

大同－阳高地震前静乐井水位记震能力的异常及其意义   总被引：1，自引：0，他引：1  

鱼金子  车用太  王爱英  张淑亮 《山西地震》1995,(1)

本文系统分析了大同６．１级地震前静乐井水位记震能力增强的异常现象，并依此为基础结合国内有关资料，初步提出了利用井水位记震能力的异常变化进行中期强震危险性判断的方法，讨论了建立这种方法的科学依据。  相似文献   

地热前兆预报地震的新方法研究   总被引：5，自引：0，他引：5  

胡敦宽  曾小苹 《地震》1995,(3):234-239

利用最大熵谱和带通滤波方法分析处理了北京白家疃井约6年的地热观测资料。结果表明,在频率域上有丰富的地热地震前兆信息;井—含水层系统的固有频率特性与地震活动存在一定关系。某些周期的振幅异常与200km范围内M_L≥4.0地震有较好的对应关系,特别是1989年10月18日大同M_s6.1地震前,用本方法处理地热观测资料,发现有明显的中期、短期和临震异常。 文中讨论了井—含水层系统产生响应频率特性的物质条件。  相似文献   

滇西古特提斯构造带玄武岩Dupal异常   总被引：7，自引：0，他引：7  

周德进  沈丽璞 《地球物理学进展》1995,10(2):39-44

滇西古特提斯构造带某些玄武岩的Ｓｒ、Ｎｄ、Ｐｂ同位素资料显示存在富集放射成因Ｐｂ同位素的Ｄｕｐａｌ异常。五素玄武岩的＾８７Ｓｒ／＾８６Ｓｒ＝０．７０６３，εＮｄ（Ｔ）＝５．４－６．５；铜厂街洋岛玄武岩的８７＾Ｓｒ／＾８６Ｓｒ＝０．７０３６－０．７０８３，εＮｄ（Ｔ）＝０．６５－６；双沟、德钦、铜厂街、勐连蛇绿岩玄武岩的＾８７Ｓｒ／＾８６Ｓｒ＝０．７０３８－０．７０７３，εＮｄ（Ｔ）＝８．２－１０．  相似文献   

应用主分量分析法研究唐山Ms7.8地震前的地磁异常     

杜安娜  高惠璇 《地震》1995,(3):291-297

应用主分量分析法对昌黎、青光、宝坻、红山等台站(1975—1977年)三年的每月五个静日地磁绝对磁场的资料及相应时间的太阳黑子相对数的资料进行计算。结果表明,第一主分量与太阳黑子相对数对应很好,相关系数为0.9以上,而第二主分量与太阳黑子相对数的相关系数为0.03左右。对于在某一固定频率而变化的地磁外源场,内外场的比例几乎恒定在一定水平上,而在唐山地震前内外场比值有明显的异常变化,笔者认为,这个恒定水平的偏离可能是由于地壳内应力不断积累导致的地下电导率的变化而引起的。用这种方法不仅可以消除地磁场的非局部变化,而且利用内外场比值的偏离或监视内场的变化可能为使用地磁场预报地震提供一个依据。  相似文献   

岩石圈强迫对气候变化的作用   总被引：3，自引：0，他引：3  

汤懋苍 《气象科学》1995,15(4):2-6

本文总结了本专题自１９９１年来所进行的工作，主要研究了多年平均地表层热流场的基本特征，季地温距平场与降水量的相关。“地热涡”，西太平洋强震与地转减慢及Ｅｌ Ｎｉｎｏ的联系，我国地震与旱涝关系，高原季风与高原的隆起等问题，提出一些新结果。  相似文献   

化探分散流异常查证方法探讨     

幸世军 《矿产与地质》2001,15(Z1):480-482

重点阐述了分散流异常与地质相结合在三南区开展异常查证的运用体会,分散流异常在三南成矿区的分布特征以及通过对分散流异常的优选勘查获得了一批较好的成矿信息,提出了异常区内如何开展地质工作的建议.  相似文献