城市化对石家庄站近地面风速趋势的影响   总被引：1，自引：0，他引：1  

卞韬  任国玉  张立霞 《气候变化研究进展》2018,14(1):21-30

利用1972—2012年石家庄城市站和4个乡村站地面风速资料,采用城乡对比方法,对石家庄城市站地面风速序列中的城市化影响进行分析,结果表明,石家庄站年和季节平均地面风速和平均10 min最大风速的长期下降趋势,主要是由城市化因素引起。具体结论如下：(1)石家庄站年和四季平均风速、平均10 min最大风速和大风日数均呈极显著的减少趋势,年平均减少速率分别为-0.15 (m/s)/10a、-1.05 (m/s)/10a和-2.90 d/10a;乡村站年平均风速呈微弱下降趋势,年平均10 min最大风速减少较为明显,年大风日数减少趋势非常显著,减少速率分别为-0.02 (m/s)/10a、-0.21 (m/s)/10a和-2.19 d/10a。(2)石家庄站年平均风速下降趋势中的城市化影响为-0.13 (m/s)/10a,城市化影响非常显著,城市化贡献率达到86.0%。该站春、夏、秋、冬季平均风速变化的城市化影响分别为-0.16 (m/s)/10a、-0.10 (m/s)/10a、-0.13 (m/s)/10a和-0.15 (m/s)/10a,城市化贡献率分别为82.8%、87.6%、88.6%和85.4%。(3)石家庄站年平均10 min最大风速变化趋势中的城市化影响为-0.84 (m/s)/10a,城市化贡献率为79.7%;春、夏、秋、冬季平均10 min最大风速变化趋势中的城市化影响分别为-0.94 (m/s)/10a、-0.80 (m/s)/10a、-0.60 (m/s)/10a和-1.01 (m/s)/10a,城市化贡献率分别达到90.4%、78.6%、64.9%和79.1%。(4)城市化对石家庄站年大风日数减少的影响不显著,但冬季大风日数减少仍明显与城市化过程有关。  相似文献   

Abrupt spatiotemporal land and water changes and their potential drivers in Poyang Lake, 2000–2012     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

Driven by various natural and anthropogenic factors, Poyang Lake, the largest freshwater lake in China, has experienced significant land use/cover changes in the past few decades. The aim of this study is to investigate the spatial–temporal patterns of abrupt changes and detect their potential drivers in Poyang Lake, using time-series Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day maximum value composite vegetation indices between 2000 and 2012. The breaks for additive seasonal and trend (BFAST) method was applied to the smoothed time-series normalized difference vegetation index (NDVI), to detect the timing and magnitude of abrupt changes in the trend component. Large part of Poyang Lake (98.9% for trend component) has experienced abrupt changes in the past 13 years, and the change patterns, including the distributions in timing and magnitudes of major abrupt trend changes between water bodies and land areas were clearly differentiated. Most water bodies had abrupt increasing NDVI changes between 2010 and 2011, caused by the sequential severe flooding and drought in the two years. In contrast, large parts of the surrounding land areas had abrupt decreasing NDVI changes. Large decreasing changes occurred around 2003 at the city of Nanchang, which were driven by urbanization. These results revealed spatial–temporal land cover changing patterns and potential drivers in the wetland ecosystem of Poyang Lake.  相似文献   

确定地壳形变观测曲线趋势转折点的定量方法与实例     

刘冠中  刘远征 《内陆地震》2013,(3):251-256

趋势转折是地壳形变变化的一个重要信息,为定量、精确地提取地壳形变观测资料的趋势转折点,基于改进的有序聚类分析法,采用时窗滑动的方法,提取时间序列的趋势转折点,并编制了相应的程序.以新源地震台地倾斜南北向1992～2006年的观测数据为例,以4年窗长、2年步长滑动计算其趋势转折点.研究结果表明：（1）采用改进的有序聚类分析法提取时间序列的趋势转折点具有明确的统计意义,可减少人为判断的主观和任意性.（2）该方法算法简单,易于实现,可用于日常的地壳形变观测资料的分析预报工作.（3）新源地震台地倾斜南北向观测数据计算结果表明,在2001年之前,趋势转折比较频繁,变化也比较明显,而在2001年之后,趋势转折较少,变化更接近线性.  相似文献   

On the prediction error variance of three common spatial interpolation schemes     

Phaedon C. Kyriakidis  Michael F. Goodchild 《International journal of geographical information science》2013,27(8):823-855

Three forms of linear interpolation are routinely implemented in geographical information science, by interpolating between measurements made at the endpoints of a line, the vertices of a triangle, and the vertices of a rectangle (bilinear interpolation). Assuming the linear form of interpolation to be correct, we study the propagation of error when measurement error variances and covariances are known for the samples at the vertices of these geometric objects. We derive prediction error variances associated with interpolated values at generic points in the above objects, as well as expected (average) prediction error variances over random locations in these objects. We also place all the three variants of linear interpolation mentioned above within a geostatistical framework, and illustrate that they can be seen as particular cases of Universal Kriging (UK). We demonstrate that different definitions of measurement error in UK lead to different UK variants that, for particular expected profiles or surfaces (drift models), yield weights and predictions identical with the interpolation methods considered above, but produce fundamentally different (yet equally plausible from a pure data standpoint) prediction error variances.  相似文献   

The FAO global capture production database: A six-decade effort to catch the trend     

Luca Garibaldi 《Marine Policy》2012,36(3):760-768

With data series extending for 60 years, including catch data for almost 1850 species items, and reflecting geo-political, historical and natural events, the FAO capture database provides a service to the community interested in fishery information. Over 600 articles from refereed journals cited the database in the last 15 years. Species included grew significantly in the last decade and an analysis of annual reporting showed more timely data submissions, although the number of non-reporting countries remained stable throughout the years. An evaluation of data quality found over half developing countries reporting inadequately but also one-fourth of reports by developed countries were not satisfactory. This article also provides meta information on historical developments, data sources and coverage, and advice on what should be kept in mind when using the database for trend studies.  相似文献   

临潭-宕昌断裂3次中强地震活动与兰州钻孔倾斜观测趋势性变化特征分析     

曾文浩  姜振海  翟玮  王小娟 《中国地震》2016,32(3):539-546

通过分析2001年10月~2015年5月兰州钻孔倾斜观测资料的变化趋势,发现由于仪器安装时未安装底座托盘而造成观测资料存在长期的趋势性漂移。利用抛物线函数对兰州钻孔倾斜观测资料进行趋势拟合后发现,临潭-宕昌断裂3次中强地震发生前兰州钻孔倾斜观测资料的拟合残差存在着一定的异常变化,因此认为兰州钻孔倾斜观测有可能较好地反映临潭-宕昌断裂的中强地震活动。  相似文献   

自然电场的区域性变化特征   总被引：10，自引：2，他引：8       下载免费PDF全文

谭大诚  赵家骝  刘小凤  范莹莹  刘君  陈军营 《地球物理学报》2014,57(5):1588-1598

以场源为分类原则,地电场E由自然电场E_SP和大地电场E_T构成.E_SP起源于地下介质物理、化学作用,通常其变化及稳定性具有明显的局部场地特征;E_T起源于空间电流系和潮汐力,在日变波形、频谱特征上表现出广域性.在形成微观机理方面,E_SP和E_T能够具有部分相同的机理过程.2008—2013年,在南北地震带附近13个代表性场地,多数E_SP不具有清晰的年变波形,其稳定性也受区域、场地、方位、构造活动等因素影响.在这些地区,E_SP较平稳的持续升降、快速跃变、突跳等现象常见,同一主断裂带附近或局部区域内,这些大幅变化的趋势转折点多具有时间同步或准同步性,同一时段数据稳定性可能类似,但形态变化存在场地因素而不具相关性.E_SP较平稳期间,应用潮汐地电场频谱特征计算的裂隙水主体渗流方位α易处于相对稳定状态,而在其剧烈变化期间的α常会明显变化.以潮汐地电场频谱特征逐日计算α值,可能揭示场地裂隙、裂隙水渗流、主压应力的逐日变化信息,进而可解析E_SP、E_T宏观变化的微观机理过程.  相似文献   

靖西县近50年气候变化特征分析   总被引：1，自引：1，他引：0  

梁琼芳  陆耀凡  凌莉  陆陈宝 《气象研究与应用》2010,31(3)

利用靖西国家基本气象站1958～2007年的气温和降水资料,运用数理统计方法,分析了靖西县近50a气温、降水的变化特征。结果表明,年平均气温、年平均最高气温、年平均最低气温、四季平均气温均呈上升趋势,1997年之后年平均气温进入一个迅速上升阶段,夏季高温天气增多,冬季低温天气减少,气候变暖主要来自于冬、秋季气温增高的贡献;降水量略呈上升趋势,但变化不明显。  相似文献   

云南各量级雨日的气候特征及变化   总被引：13，自引：1，他引：12       下载免费PDF全文

彭贵芬  刘瑜 《高原气象》2009,28(1):214-219

利用1959-2005年云南125个测站的雨量资料,通过计算趋势系数等现代统计诊断方法,研究了云南中雨日、大雨日、暴雨日、大暴雨日及各量级降水量的气候特征和变化,并与雨日的气候变化做了对比分析.结果表明,云南中雨以上强降雨日有明显的干、雨季之分,雨季中雨、大雨、暴雨、大暴雨日数分别占全年中雨、大雨、暴雨、大暴雨日数的84%,90%,94%,99%,特别是6～8月大雨以上强降雨日占全年的61%以上,强雨日的集中程度相当高,且降雨量级越大集中越高.云南大雨日、暴雨日、大暴雨日在增多;大雨日的增多趋势不明显,暴雨日、大暴雨日的增多趋势较明显,且大暴雨日比暴雨日的增多趋势大.雨日、中雨日在减少;雨日的减少趋势十分明显.以每10年平均计算,云南省内总大雨日增多6.9天,暴雨日增多4.3天,大暴雨日增多0.7天,中雨日减少75.4天;云南省内站平均雨日减少7.6天.云南年降水量有减少的趋势,全省减少量是每10年平均减少15.3 mm;大雨量、暴雨量和大暴雨量稍有增多,但变化趋势不明显;小雨量、中雨量有较明显的减少趋势.  相似文献   

内蒙古呼伦湖沙丘带形成原因分析   总被引：1，自引：0，他引：1  

李孝荣  包双喜  长顺  白明 《内蒙古气象》2009,(3):30-31

近年来,内蒙古呼伦湖地区降水偏少、气温偏高,导致湖水水位下降。引起沙丘带的面积逐渐增加。文章基于新巴尔虎右旗30年气象资料变化,试分析呼伦湖沙丘带形成原因。并分析沙丘带发展趋势。  相似文献