长白山苔原带土壤温度与肥力随海拔的变化特征   总被引：3，自引：0，他引：3  

高雅芳  王雷  杜海波  吴正方  杨岳  郭湘宇  李思其 《冰川冻土》2018,40(4):702-714

土壤温度与土壤肥力的分解释放、植被生长密切相关。利用2015年8月至2017年6月长白山西坡苔原带5 cm土壤温度并测试其土壤肥力,分析了土壤温度与肥力随海拔的变化特征及土壤温度对苔原带肥力的影响。结果表明：（1）长白山西坡苔原带土壤最热月为8月,最冷月为1、2月。长白山西坡苔原带土壤年均温随海拔的升高而下降,垂直变化率为-0.44℃·（100m）^-1。月均温垂直变化率则有所差别,5-9月垂直变化率为正,其余月份垂直变化率为负。（2）海拔是土壤温度空间分异的主要影响因素,冷季土壤温度随海拔升高而显著降低。随着海拔升高,越稀疏的植被和越薄的土层使得土壤热容量越小,暖季土壤温度随海拔升高而显著升高。（3）长白山西坡苔原带土壤肥力,尤其是与植物生长关系密切的速效养分随海拔升高表现出先升高再降低,在植物多样性和丰富度及草本植物盖度最高的2 250 m处达到土壤肥力最高水平。低海拔（2 050~2 250 m）的土壤肥力水平明显高于高海拔（2 350~2 550 m）的土壤肥力水平。西坡苔原带土壤肥力的空间分异状况受草本植物入侵影响较大。（4）长白山西坡苔原带土壤肥力水平随土壤温度升高而升高,温度是土壤有机质分解和矿物质养分转化的限制性因素。建议山地苔原带生态系统生产和生态管理中要重点考虑草本植被入侵给土壤肥力带来的影响。  相似文献   

磁铁矿的穆斯堡尔谱研究     

郑裕芳  余正方  卢敬业  吴杰陶  杜金龄  邓璟  姚德贤 《矿物学报》1986,(1)

我们对大冶、马坑、大顶、黄沙坪、鞍山五个矿区的七个铁矿石样品中的磁铁矿作了室温~(57)Fe和~(119)Sn穆斯堡尔谱测定,并根据穆斯堡尔数据和化学分析推算出磁铁矿的非理想配比的分子结构式. 初步研究表明,不同的成矿条件和Zn、Mg等二价阳离子的类质同像替代的多少,明显地影响晶胞参数和穆斯堡尔参数.文中讨论了它们的变化规律性.  相似文献   

关于发展我国地震科技信息工作的思考     

陈宇卫  董梅 《国际地震动态》1995,(7):9-12

地震科技信息的积累和应用是我国地震科学事业发展的基础，我国的地震信息工作在地震预报的探索和研究中以及地震工程应用中，均发挥了重要的作用，为进一步认识地震科技信息的重要性，发展这一事业，本文就地震科学研究与地震科技信息的内在联系，地震科技信息的运行机制及地震科技信息工作的发展提出了一些新的观点。  相似文献   

REMOTE SENSING OF THE SEASONAL VARIATION IN COLUMN ABUNDANCE OF ATMOSPHERIC CH₄^*          下载免费PDF全文

WEI Heli  LIU Qinghong  XU Qingshan  ZHAO Fengsheng  SONG Zhengfang 《Acta Meteorologica Sinica》2001,15(2):249-256

Infrared solar spectra on clear days were measured automatically by an infrared solar spectrometer(ISS) with 0.4 cm^-1 resolution developed by us.A line-by line(LBL) computation method was used to calculate theoretical atmospheric absorption.In the wavelength range of 3.410-3.438 μm.the absorption is mainly due to atmospheric methane and water vapor.Columnatmospheric methane was retrieved from the recorded infrared solar spectra.The seasonal variation of column atmospheric methane in Hefei has been obtained from the measuremental data of nearly 18 months since the April of 1997.and found that it is similar to that of background data.The instruments.principles of measurement and some of results were introduced,and the results are also discussed briefly in the paper.  相似文献   

1961—2010年东北地区四季开始日及长短变化特征分析   总被引：4，自引：1，他引：3  

王雷  吴正方  杜海波  宗盛伟 《气象科学》2014,34(5):499-507

用1961—2010年东北地区90个气象观测站的观测资料,采用钱诚等四季划分的方法,分析了东北地区四季开始日、长短变化特征及其对农业的影响。研究表明:东北地区近50 a来,四季(春、夏、秋、冬)平均开始日分别为4月10日、6月25日、8月11日和10月20日,平均长度分别为80 d、51 d、72 d和171 d,且区域差异比较明显。春季和夏季的开始日在明显提前,分别为-1.46 d/10a、-1.99 d/10a;秋季和冬季的开始日明显推迟,分别为2.05 d/10a、0.90 d/10a。平均春、秋和冬季的持续时间在缩短,分别为-0.54 d/10a、-1.15 d/10a、-2.50 d/10a,春、秋季的变化未通过显著性检验,冬季通过了0.05的显著性检验。夏季时间延长,为3.38 d/10a。春季的提前和秋季的推迟,使农作物适宜生育期延长;同时对作物品种熟性和种植格局也会产生一定的影响。  相似文献   

Decreasing precipitation occurs in daily extreme precipitation intervals across China in observations and model simulations     

Lei Wang  Wen J. Wang  Haibo Du  Zhengfang Wu  Xiangjin Shen  Shuang Ma 《Climate Dynamics》2020,54(5):2597-2612

Extreme precipitation response to increasing temperature includes not only changes of frequency and intensity, but also changes of extreme precipitation interval (EPIV) and the precipitation during the neighboring daily extreme precipitations interval (EPIP). These changes have not been fully evaluated yet in observations or climate model simulations although they are very useful to understand variations of extreme precipitation. We used daily precipitation data from 669 meteorological stations during the past five decades across China and projections of 19 general circulation models from CMIP5 under the RCP4.5 and RCP8.5 scenarios to investigate variations of EPIV and EPIP. We found the national average annual EPIV increased across China during the last five decades, while annual EPIP significantly decreased. The decreases mainly occurred in southwest China, east China, and southeast China. At national and regional scales, the average annual EPIV and EPIP showed greater decreases under the RCP8.5 scenario than those under the RCP4.5 scenario from 2006 to 2100. Annual EPIP showed a stronger correlation with extreme precipitation intensity than EPIV. The national average annual EPIP had a significant positive correlation with the Western Pacific Subtropical High Area Index. The abnormal geopotential heights over western Mongolia and the western Pacific at 500 hpa as well as the abnormal SSTs in Japan Sea and the western of Pacific in rainy seasons would result in abnormal annual EPIVs and EPIPs in China. This study may provide references for flooding prediction, water resources management, and disaster prevention and mitigation.  相似文献   

黄海沉积物标准物质研制   总被引：6，自引：0，他引：6  

吕海燕  王正方  陈维岳  高爱国 《海洋通报》2004,23(5):71-76

报道了中国黄海海洋标准物质的研制过程,其中包括样品的采集、制备,均匀性检验、稳定性考察以及定值分析方法,并对数据进行了数理统计,给出了标准物质的定值数据。最后确定标准值45个,参考值8个,信息值11个,共计测定元素64个。  相似文献   

Hazard Assessment of Co-seismic Landslides Based on Information Value Method: A Case in 2018 MW6.6 Hokkaido Earthquake, Japan     

WEN Boyu  XU Chong  HE Xiangli  MA Siyuan  SHAO Xiaoyi  LI Kai  ZHANG Zhongjian  LI Zhengfang 《中国地震研究》2020,34(1):64-80

An M_W6.6 earthquake occurred in eastern Hokkaido, Japan on September 6^th, 2018. Based on the pre-earthquake image from Google Earth and the post-earthquake image from high resolution (3 m) planet satellite, we manually interpret 9 293 coseismic landslides and select 7 influencing factors of seismic landslide, such as elevation, slope, slope direction, road distance, flow distance, peak ground acceleration (PGA) and lithology. Then, 9 293 landslide points are randomly divided into training samples and validation samples with a proportion of 7:3. In detail, the training sample has 6 505 landslide points and the validation sample has 2 788 landslide points. The hazard risk assessment of seismic landslide is conducted by using the information value method and the study area is further divided into five risk grades, including very low risk area, low risk area, moderate risk area high risk area and very high risk area. The results show that there are 7 576 landslides in high risk area and very high risk area, accounting for 81.52% of the total landslide number, and the landslide area is 22.93 km², accounting for 74.35% of the total area. The hazard zoning is in high accordance with the actual situation. The evaluation results are tested by using the curve of cumulative percentage of hazardous area and cumulative percentage of landslides number. The results show that the success rate of the information value method is 78.50% and the prediction rate is 78.43%. The evaluation results are satisfactory, indicating that the hazard risk assessment results based on information value method may provide scientific reference for landslide hazard risk assessment as well as the disaster prevention and mitigation in the study area.  相似文献   

工程结构柱式构件的抗震性能试验研究进展     

董正方  王君杰  韩鹏 《震灾防御技术》2010,5(1):43-52

为研究工程结构中柱式构件的抗震性能,本文对国内外普通混凝土柱、高强混凝土柱、钢管混凝土柱和钢骨混凝土柱的抗震拟静力试验结果进行了总结,得出了影响柱式构件抗震性能的几个关键因素,并对研究中存在的不足以及今后需要探讨的问题进行了讨论。  相似文献   

潜源划分进展及我国海域和邻近海域区划潜源划分问题研究     

董绍鹏  温增平  任治坤  李正芳  高战武 《震灾防御技术》2021,16(1):51-61

对于陆域地区,我国已进行5次全国范围大面积地震区划研究工作,获得了丰富研究成果.但对于海域地区地震区划的研究较薄弱,较少涉及海域潜源划分模型.随着经济发展,涉及海域地区的经济活动日益频繁,对海域地区潜源划分研究及进一步地震区划研究工作的需求越来越强烈.为此,详细介绍代表性国家在潜源划分方面采取的原则和方法,总结我国海域...  相似文献