莱西市加强耕地保护初探   总被引：1，自引：1，他引：0  

于桂清  李文云  张少华 《山东国土资源》2010,26(6):38-39,43

莱西市从土地利用详查数据入手,通过对比分析近年来该市各类土地面积变化趋势,指出进一步加强耕地保护的重要性和必要性,并就如何加强耕地保护工作提出了具体措施和建议。  相似文献   

Spatial and temporal variability of satellite-derived sea surface temperature in the southwestern Atlantic Ocean     

Andrés L. Rivas 《Continental Shelf Research》2010

  相似文献   

湘中南晋宁期和加里东期构造线走向变化成因     

柏道远  贾宝华  钟响  贾朋远  刘耀荣 《地质力学学报》2012,18(2):165-177

湘中南晋宁期和加里东期构造线走向横向上存在显著变化,通道-溆浦-安化-桃江一线晋宁期与加里东期构造线呈向北西凸出的弧形弯曲;湘东浏阳-川口一带晋宁期构造线自北而南由东西向转为北东-北北东向,加里东期构造线在湘南九嶷山地区和彭公庙-汝城一带为东西向,在都庞岭-塔山隆起带以及高挂山-关帝庙隆起带呈北东-北北东向,在湘中大乘山-龙山一带呈东西向。地质与地球物理资料显示湖南境内钦杭结合带与扬子陆块分界可能沿南桥-新化-隆回-苗儿山一线,自东向西由东西向转为北北东向;与华夏陆块分界可能沿川口-常宁-双牌一线,呈北东向。通过与区域挤压应力方向结合,上述构造边界走向可以较好地解释湘中南地区晋宁期和加里东期构造线方向的若干横向变化特征。   相似文献   

丹江口库区本底地震与水库地震趋势分析     

刘文清  朱建  徐新喜  宋伟  刘华清  黄飞 《地震地磁观测与研究》2015,(3):58-62

从丹江口库区地震地质构造着手,总结公元前143年至公元2008年本底地震活动情况,分析在初期蓄水阶段水库诱发地震活动情况、强度及成因。讨论丹江口水库增容后,新增库水对库区的应力状态影响,探讨库区及周缘地区可能诱发水库地震的区域及强度。结果发现,丹江口库区中的汉库诱发地震可能性不大。而丹库可能诱发地震,其强度应在M≤5.0。主要诱发地震危险区仍在丹库宋湾—关防滩峡谷地形库段和林茂山—凉水河地区。  相似文献   

新疆塔河流域洪水量级、频率及峰现时间变化特征、成因及影响   总被引：2，自引：0，他引：2  

顾西辉  张强  孙鹏  肖名忠  孔冬冬 《地理学报》2015,70(9):1390-1401

采用塔里木河流域（塔河流域）8个水文站及相应气象站数据,全面分析了洪水发生量级、频率和峰现时间等特征,研究洪水发生成因及其影响。结果表明：1980s中后期塔河流域气温与降水持续增加,整个塔河流域年及季节洪峰流量普遍呈上升趋势,大部分在1980s中后期发生突变。1980s中期以后塔河流域年及季节洪峰流量呈持续增加或者显著增加趋势,量级位于整个观测时期均值之上,处于洪水“丰富”期。“丰富”期暴雨型和升温型洪水发生次数及造成的灾害损失均呈显著增加趋势,引起严重洪灾损失的洪水也集中在这一时期,且多由暴雨型洪水引发。大量级洪水（最大三场洪水及重现期大于10年的洪水）多集中发生在1990年之后,并且易引发多个水文站点同时出现。  相似文献   

Toward a luminescence chronology for coastal dune and beach deposits on Calvert Island,British Columbia central coast,Canada     

《Quaternary Geochronology》2015

The Quaternary geology of the central coast of British Columbia contains a rich and complex record of glacial activity, post-glacial sea level and landscape change, and early human occupation spanning the last ∼10,000 years. At present, however, this region remains a largely understudied portion of coastal North America. This study describes the luminescence characteristics of quartz and K-feldspar from coastal dune and beach sands on Calvert Island and develops a suitable optical dating protocol that will allow for a more rigorous chronology for post-glacial landscape evolution and human occupation on British Columbia's central coast. Luminescence signals from Calvert Island quartz are dim, and appear to lack the so-called “fast” component that is most desirable for optical dating. K-feldspar signals are sufficiently bright for optical dating. We test and refine a single-aliquot regenerative-dose (SAR) protocol for K-feldspar specific to Calvert Island samples through a series of dose recovery and preheat plateau tests. Two approaches for correcting a sample age for anomalous fading are compared and a correction for phototransfer is introduced and applied. Measured fading rates vary from sample to sample implying that, in this region, it is not sufficient to rely on two or three representative fading rates as has sometimes been done elsewhere. Refined age estimates show consistency with independent radiocarbon dating control and help identify radiocarbon-dated organic-rich sediments that have been reworked.  相似文献   

2015尼泊尔大地震及喜马拉雅造山带未来地震趋势   总被引：1，自引：1，他引：0  

赵根模  刘杰  吴中海 《地质力学学报》2015,21(3):351-358

2015年4月25日尼泊尔M_s 8.1级大地震是发生在喜马拉雅造山带中段的低角度逆冲断层运动, 特点是震源很浅, 震中烈度达Ⅺ度, 震害严重。破裂带走向北西西—南东东, 穿越尼泊尔首都加德满都, 使首都建筑遭受严重破坏。该震是1934年以来尼泊尔最大地震, 标志着喜马拉雅带自1950年以来半个世纪的平静期已经结束。自2005年进入新活动期, 至2015年尼泊尔大地震发生已达到活动高潮。预计将持续十到几十年。根据历史地震资料分析, 今后可能沿喜马拉雅带走向发生纵向迁移, 将在喜马拉雅带东段发生更大的地震, 从而使地震高潮达到顶峰而结束, 可能对我国西藏东南、不丹和印度边界产生破坏。另外还可能沿着与喜马拉雅带走向垂直方向向北迁移(即横向迁移), 在几年之内即可在西藏、青海引起破坏性地震, 需要相关省市做好监测预报和防灾工作。   相似文献   

Spatio-temporal variation of photosynthetically active radiation in China in recent 50 years     

ZHU Xudong  HE Honglin  LIU Min  YU Guirui  SUN Xiaomin  GAO Yanhua 《地理学报》2010,20(6):803-817

Based on long-term measurement data of weather/ecological stations over China, this paper calculated and produced annually- and seasonally-averaged Photosynthetically Active Radiation (PAR) spatial data from 1961 to 2007, using climatological calculations and spatialization techniques. The spatio-temporal variation characteristics of annually- and seasonally-averaged PAR spatial data over China in recent 50 years were analyzed with Mann-Kendall trend analysis method and GIS spatial analysis techniques. The results show that: (1) As a whole, the spatial distribution of PAR is complex and inhomogeneous across China, with lower PAR in the eastern and southern parts of China and higher PAR in the western part. Mean annual PAR over China ranges from 17.7 mol m-2 d-1 to 39.5 mol m-2 d-1. (2) Annually- and seasonally-averaged PAR of each pixel over China are averaged as a whole and the mean values decline visibly with fluctuant processes, and the changing rate of annually-averaged PAR is –0.138 mol m-2 d-1/10a. The changing amplitudes among four seasons are different, with maximum dropping in summer, and the descending speed of PAR is faster before the 1990s, after which the speed slows down. (3) The analysis by each pixel shows that PAR declines significantly (α=0.05) in most parts of China. Summer and winter play more important roles in the interannual variability of PAR. North China is always a decreasing zone in four seasons, while the northwest of Qinghai-Tibet Plateau turns to be an increasing zone in four seasons. (4) The spatial distributions of the interannual variability of PAR vary among different periods. The interannual variabilities of PAR in a certain region are different not only among four seasons, but also among different periods.  相似文献   

Regional soil moisture simulation for Shaanxi Province using SWAT model validation and trend analysis   总被引：1，自引：0，他引：1  

LI MingXing    MA ZhuGuo & DU JiWen Key Laboratory of Regional Climate-Environment Research for Temperate East Asia 《中国科学:地球科学(英文版)》2010,(4)

The soil moisture in Shaanxi Province,a region with complex topography,is simulated using the distributed hydrological model Soil Water Assessment Tool(SWAT).Comparison and contrast of modeled and observed soil moisture show that the SWAT model can reasonably simulate the long-term trend in soil moisture and the spatiotemporal variability of soil moisture in the region.Comparisons to NCEP/NCAR and ERA40 reanalysis of soil moisture show that the trend of variability in soil moisture simulated by SWAT is more...  相似文献   

地统计法在粒径趋势分析中的应用:以北部湾东部为例(英文)   总被引：4，自引：1，他引：3  

马菲  汪亚平  李炎  叶长江  徐志伟  张凡 《地理学报(英文版)》2010,20(1):77-90

There are 71 surface sediment samples collected from the eastern Beibu Gulf. The moment parameters (i.e. mean size, sorting and skewness) were obtained after applying grain size analysis. The geostatistical analysis was then applied to study the spatial autocorrelation for these parameters; while range, a parameter in the semivariogram that meters the scale of spatial autocorrelation, was estimated. The results indicated that the range for sorting coefficient was physically meaningful. The trend vectors calculated from grain size trend analysis model were consistent with the annual ocean circulation patterns and sediment transport rates according to previous studies. Therefore the range derived from the semivariogram of mean size can be used as the characteristic distance in the grain size trend analysis, which may remove the bias caused by the traditional way of basing on experiences or testing methods to get the characteristic distance. Hence the results from geostatistical analysis can also offer useful information for the determination of sediment sampling density in the future field work.  相似文献