陕西苹果成熟期连阴雨指数及预报方法研究   总被引：2，自引：0，他引：2  

刘璐  马杰 《气象》2012,38(8):1012-1016

选取陕西苹果30个生产基地县中果业发展水平具有代表性的12个台站,近50年(1961—2009年)9月中旬至10月上旬苹果成熟期连续3天及以上降水日数和无降水日数资料,设计并计算其连阴雨指数。将连阴雨指数分成强、偏强、中等、偏弱和弱5个等级,并用典型K阶自回归AR(K)预测模式进行独立样本预测试验。结果表明连阴雨指数能够较客观地反映基地县的连阴雨强度,且典型K阶自回归预测模式预测准确及基本准确率在83%左右,预报效果尚好,具有实用价值。  相似文献   

中国近50年气温变化准3年周期的普遍性及气温未来的可能变化趋势   总被引：8，自引：0，他引：8  

王澄海  李健  许晓光 《高原气象》2012,31(1):126-136

利用全国98个测站的年和冬季气温资料,采用Marr小波分析方法,分析了近50年(1961—2009年)中国8个气候区的年和冬季气温变化,研究了中国气温变化的周期性,并对未来20年(2010—2029年)气温的可能变化趋势进行了预测。结果表明,我国8个气候区气温的年际变化以高频变化为主,普遍存在着准3～4年周期变化,尤其是冬季气温的准3年周期变化显著,而且这种周期变化具有相对的稳定性。而年气温的周期特征存在显著的南北差异。周期叠加外推的结果表明,未来20年,中国将继续保持增暖趋势,北方地区和青藏高原的升温要大于除西南地区外的南方地区。如果按照线性趋势升温,2010-2029年气温上升幅度不会超过1℃。  相似文献   

“后地段时代”我国房地产开发     

程诚 《地域研究与开发》2012,31(3):64-67

由于社会经济发展和城市建设深化,房地产开发和城市建设的影响因子日益多元化,使得以地段为标志的区位因素在房地产开发和城市发展建设中的地位正趋于弱化,"唯地段论"日益面临挑战。在批评"唯地段论"的基础上,提出了"后地段时代"概念,分析了"后地段时代"房地产区位弱化的成因,探讨了"后地段时代"我国房地产开发受到的影响及调整思路。  相似文献   

历史时期中国重大自然灾害时空分异特征(英文)   总被引：4，自引：0，他引：4  

刘毅  杨宇  李莉 《地理学报(英文版)》2012,22(6):963-976

Based on historical documents and records this paper analyzes the characteristics of frequency and distribution of major disasters that took place in the history of China. The findings show that occurrences of different types of disasters varied and spatial pattern at provincial level are significantly different as well. The results also indicate that there is a strong relationship between type of disasters and spatial distribution and that the spatial pattern of losses was not the same as that of the frequency. The reasons are: (1) the hazard-formative environments which, to a large extent, determine the spatial pattern of the disasters are significantly different; (2) the losses caused by natural disasters were closely related to the concentration of economy and population. Number of deaths was usually large in areas where agriculture, culture and business were relatively developed. The spatial pattern of disaster losses is an evitable result of uneven economic development in the history of China.  相似文献   

陇东地区近51 a气温时空变化特征   总被引：5，自引：0，他引：5  

王媛媛  张勃 《中国沙漠》2012,32(5):1402-1407

 基于陇东地区15个气象站点1957—2007年的月平均气温、日平均气温资料,结合GIS空间分析技术和数理统计理论,对其气温变化进行定量化分析,阐述其时空演变特征。结果表明,陇东地区多年平均气温较高的地方在中部地区,西部地区平均气温较低,主要是受地形影响;年均气温总体呈上升趋势,春、冬季的增温趋势最为明显,这与全球气温变化及中国气温变化总体趋势一致;年均气温变化的第一主周期为13 a,四季平均气温变化的第一主周期分别是25 a、25 a、13 a和7 a;年均气温的突然升高开始于20世纪80年代中期,四季平均气温的突然升高分别始于90年代中期、90年代初、80年代末和90年代初。  相似文献   

荞麦作物观测技术简介   总被引：1，自引：0，他引：1  

赵翠珍  陈晓梅  张慧萍 《内蒙古气象》2012,(5):30-32

文章介绍了荞麦作物的生长特性、环境要求及荞麦发育期、发育期标准、生长状况测定、产量结构分析、大田生长状况调查等观测内容和技术要求,可供测站在荞麦发育期观测和服务时参考。  相似文献   

2011年江苏出梅日界定之我见   总被引：1，自引：0，他引：1  

李建国  孔启亮  姚素香  赵栋  王燕 《气象科学》2012,32(5):559-564

利用实况观测数据和NCEP/NCAR再分析资料,对2011年江苏出梅日的界定进行探讨,并将7月4 -20日的低温高湿多雨、寡照的异常气候判定为“倒黄梅”,在此基础上,对比分析了2011年和2009年的两次“倒黄梅”天气过程.结果表明:(1)2011年江苏出梅日为6月30日;(2)出梅后的7月4-20日是“倒黄梅”天气过程;(3)北上台风对梅雨和“倒黄梅”结束具有重要的指示意义;(4)“倒黄梅”和梅雨(含“二度梅”)的天气特点为:前者冷暖空气频繁交替、雨带多经向分布、中低空温湿场反位相配置,常为低温高湿的局地对流性降水;而后者冷暖空气稳定对峙、雨带多纬向分布、中低空温湿场同位相配置,常为高温高湿的大范围稳定性降水.  相似文献   

输入界面对场地地表地震动参数的影响     

曹均锋  冯伟栋  董双林  原贺军 《中国地震》2015,31(2):353-361

本文以江淮地区典型场地资料为原型,选取不同深度的岩层位置作为地震动输入界面,构造多种场地土层模型,选择Taft、Kobe和E1centro 3条强震记录作为地震输入,采用一维频域等效线性化波动方法重点分析了地震动输入界面对场地地表地震动参数的影响。研究结果表明,随着输入界面深度的增加,场地地表的峰值加速度逐渐增加,且增加的幅度呈逐渐减小的趋势,但输入界面深度对地表加速度反应谱特征周期的影响较小;输入界面剪切波速值对反应谱特征周期影响有限,但对地表峰值加速度影响较为显著,地表峰值加速度随着输入界面剪切波速的增大而增大,且两者的增幅呈现近似的线性关系。  相似文献   

滇西北地区地磁短周期变化特征研究     

袁伊人  李琪  朱培育 《地震地磁观测与研究》2015,(3):77-82

利用滇西北地磁台阵8个测点的秒采样观测数据,对短周期事件的地磁三分量变化幅度进行统计,得到不同周期的垂直分量和水平分量变化幅度比值ΔZ/ΔH在观测区的空间分布,由此推测地下存在一条NNW走向的高导带,从地壳延伸至上地幔,且位置随深度不断变化。  相似文献   

analyses on the triggering facrors of large quantities of landslides in the upper reaches of the minjiang river,sichuan province     

LI Yan-hao  JIANG Han-chao  XU Hong-yan  LIANG Lian-ji 《地震地质》2015,37(4):1147-1161

Over the past geological and historical period, tens of thousands of landslides occurred in the upper reaches of the Minjiang River, an area which is characterized by alpine valleys and has been densely populated over the past several hundreds of years. Discussing the triggering factor of these landslides is of great significance to geological hazard mitigation and prevention in this region. In this paper, we focus on four aspects of regional rainfall, shape features of landslide slopes, the corresponding relationship between landslide area and earthquake magnitude, and the recurring features of the reconstructed palaeoearthquake record at Diexi. Compared with those in Nepal, both mean seasonal rainfall accumulation and mean daily rainfall for the past 30 years are too low to reach the threshold values triggering landslides in the upper reaches of the Minjiang River. Secondly, landslides in the study area are usually absent of inner gorges(canyon topography)on the hillslope toes, which are confirmed in previous studies as typical features of landslides triggered by storms. Thirdly, wide distribution of the landslides in the study area supports our notion of earthquake-triggering because the landslides triggered by storms commonly distribute locally. Fourthly, periodicity analysis of the reconstructed palaeoearthquake record at Diexi provides a few cycles of twenty to thirty years, possibly corresponding to the earthquakes of magnitudes>5.0 or 5.5 which are believed to have caused soft-sediment deformation in the study area. In contrast, like the 2008 M_S8.0 Wenchuan earthquake, the average recurrence interval of the large earthquakes in the study area is 2.6ka. They caused tens of thousands of landslides and provided more coarse silt particles for the nearby lake sediments at least in 330 years for each time. This is consistent with exponential increase of earthquake magnitude from large to medium and of the landslide area with the increased earthquake magnitude. To sum up, we suggest that tens of thousands of landslides in the upper reaches of the Minjiang River were most likely triggered by earthquakes instead of storms. This preliminary viewpoint needs further examination in the future.  相似文献