遥感科学与技术专业本科创新人才培养能力评价体系     

张玉娟  曲建光  刘丹丹  梅晓丹  张利平  田静 《测绘与空间地理信息》2020,(2):1-4

通过调查走访,设计、分发、回收纸质、电子问卷,查阅期刊等调查方式收集与遥感科学与技术专业本科创新人才培养能力相关的评价项,将出现次数大于总次数10%的评价项作为最终的专业创新人才培养能力评价指标;根据评价指标含义确定各二级指标对应的评价依据,构建了新时期遥感科学与技术专业本科创新人才培养能力评价体系。该体系可用于遥感科学与技术专业本科创新人才培养能力现状的评价,为后期高校从多方面提高创新人才培养能力提供基础。  相似文献   

遥感数据时空尺度对地理要素时空变化分析的影响     

万昌君  吴小丹  林兴稳 《遥感学报》2019,23(6):1064-1077

地理要素的时空变化分析对于了解和掌握地表的规律性有着重要的作用。利用地面站点观测、实地调查等传统方式获取数据,对地理要素进行时空变化分析是最常用的方法。但该类方法往往表现的是"点尺度"观测,不能在大尺度情况下准确地反映地表的时空变化信息。遥感卫星能以一定的时间间隔获得空间连续的对地"面尺度"观测数据,然而其特定的空间和时间分辨率使其获取的地表信息仍十分有限。同时地表的空间异质性和个别地表短时间内的快速变化,使得利用遥感数据对地理要素进行时空变化分析时,时空变化分析结果会随观测尺度而发生改变。本文从空间尺度和时间尺度两方面综述遥感数据时空尺度对地理要素的时空变化分析产生的影响和原因,并针对这些问题总结了减小时空尺度对结果不确定性影响的现行方法。可以通过多源遥感协同观测和反演、尺度转换、空间建模等方法减小空间尺度引起的不确定性;通过联合多时相遥感数据的方法减小时间尺度引起的不确定性。在实际应用中,应根据所观测地理要素的实际情况,综合分析选择合适的方法。  相似文献   

近58年华北地区初、终霜日及无霜期变化特征分析     

焦文慧  张勃  马彬  崔艳强  邢立亭  王晓丹  黄浩 《高原气象》2021,40(2):343-352

基于华北地区90个气象站点1961-2018年地面0 cm日最低温度和平均气温资料,采用线性倾向估计、反距离加权、Mann-Kendall检验、累积距平法,研究了近58年华北地区初、终霜日和无霜期的变化特征.结果表明:(1)在年际和年代际尺度上,华北地区初、终霜日和无霜期均分别呈显著推迟、提前和延长的趋势,从20世纪8...  相似文献   

梁铰型屈服RC框架结构地震弹塑性位移增大系数研究     

蔡健  周靖  方小丹 《地震工程与工程振动》2007,27(5):48-54

本文通过弹性和弹塑性时程分析,研究了水平地震作用下梁铰型屈服RC框架模型结构的楼层屈服剪力系数、基本自振周期、楼层数3个因素对弹塑性位移增大系数的影响,通过非线性回归分析给出了弹塑性层间位移增大系数经验公式;通过分析滞回耗能沿楼层高度的分布,初步确定了梁铰型屈服RC框架结构的薄弱楼层位置;基于结构损伤分析,讨论了抗震规范中RC框架结构弹塑性层间位移角限值的水准。  相似文献   

清远市一次强对流天气过程分析   总被引：16，自引：15，他引：1  

罗晓丹 《广东气象》2005,(3):14-15

对2005年3月22日发生在清远市的强对流天气的环流背景进行剖析,辅以雷达回波和卫星云图找出发生此次强对流天气的原因,是南支槽东移、发展,在槽前产生强烈的水汽辐合以及热力抬升,合适的单站地面要素和物理量场为这次强对流天气的发生提供了有利的条件。  相似文献   

Further study on the effect of buffer zone size on regional climate modeling     

Zhong Zhong  Xiaodan Wang  Wei Lu  Yijia Hu 《Climate Dynamics》2010,35(6):1027-1038

In this study, the effect of buffer zone size on the performance of a regional climate model (RCM) was investigated. In contrast to carrying out simulations where the buffer zone expands inward, numerical experiments were performed with the buffer zone expanded outward, which ensured an objective comparison on the effect of buffer zone sizes. Case simulations on the abnormal 1998 East Asian summer monsoon demonstrated that an RCM’s performance depended on the outward expansion of the buffer zone. Moreover, a broader buffer zone is able to improve large-scale circulation simulation in the upper troposphere; however, a narrower buffer zone shows better performance in the middle and lower troposphere. Numerical experiments show that the performance of RCMs in simulating the seasonal evolution of rainbands over eastern China is not completely consistent with that of the western Pacific subtropical high (WPSH). A possible reason why the configuration with the buffer zone expanding inward can improve the extension/withdrawal of the summer monsoon and the associated precipitation evolution over eastern China is discussed.  相似文献   

Assessing potential impacts of climatic change on subalpine forests on the eastern Tibetan Plateau     

Wang Xiaodan  Cheng Genwei  Zhong Xianghao 《Climatic change》2011,108(1-2):225-241

Forest gap models have been used widely in the study of forest dynamics, including predicting long-term succession patterns and assessing the potential impacts of climate change on forest structure and composition. However, little effort is devoted to predict forest dynamics in the high elevation areas, although they have the sensitive response to global climate change. In the present study, based on a modified height-diameter function, we developed a new version (FAREAST-GFSM) of the forest patch model, FAREAST for simulating the changes of subalpine forests. The observed data from the Gongga Mt. Alpine Station were also used to test model precision. With the improved performance of FAREAST-GFSM, we explored the impact of three warming scenarios on subalpine forest on the eastern Tibetan plateau within a 100-year period. The study result indicates that the effects of climate change were evident on subalpine forests in the high elevation areas. The response of different species to the warming climate might eventually transform the subalpine Abies fabric forest into Betula utilis forest similar to that which is now widely distributed in the eastern Tibetan Plateau mountainous areas with the relatively lower elevation. Subalpine forests could move to higher and colder areas, which are currently tundra.  相似文献   

热液石英中微量元素特征及应用:认识与进展   总被引：7，自引：0，他引：7  

陈小丹  陈振宇  程彦博  叶会寿  汪欢 《地质论评》2011,57(5):707-717

文章以热液石英为研究对象,基于石英的晶体结构特征和化学性质,以及近年来国内外在此领域取得的认识和成果,论述了石英中微量元素的赋存状态和应用.研究表明,微量元素主要以3种方式进入到石英晶体中:单原子替代、原子团替代和补偿电价替代.石英在SEM-CL图像中的亮度和石英中微量元素的分布具有一定的相关性,根据石英的微量元素组成...  相似文献   

利用GLDAS资料分析黄土高原半干旱区土壤湿度对气候变化的响应   总被引：1，自引：0，他引：1  

程善俊  管晓丹  黄建平  季明霞 《干旱气象》2013,(4):641-649

利用GLDAS资料分析了1948~2010年黄土高原半干旱区气温、降水和土壤湿度的变化趋势,并重点讨论了气温和降水对土壤湿度的影响和相对贡献。结果表明:近60 a来黄土高原半干旱区整体呈现暖干化趋势,增温速率明显高于全球平均增温速率;不同深度的土壤湿度的长期变化均呈减小趋势,且年际间变化明显。不同深度的土壤湿度和气温呈负相关关系,并随着土壤加深,两者的相关性加强;土壤湿度和降水则呈正相关关系,相关关系最大出现在表层土壤。通过分析气温和降水在不同季节对土壤湿度的相对贡献发现,春季和冬季气温对土壤湿度的相对贡献较降水显著,秋季恰好相反,夏季气温和降水对土壤湿度的相对贡献大小相当。对比不同深度层降水、气温对土壤湿度的相对贡献得出,降水对浅层土壤湿度有显著作用,而气温对深层土壤湿度的作用更明显。  相似文献   

The Dynamic and Thermodynamic Effects of Relative and Absolute Sea Surface Temperature on Tropical Cyclone Intensity   总被引：1，自引：0，他引：1       下载免费PDF全文

SUN Yuan  ZHONG Zhong  HA Yao  WANG Yuan  WANG Xiaodan 《Acta Meteorologica Sinica》2013,27(1):40-49

Several numerical experiments were performed to investigate the dynamic and thermodynamic effects of sea surface temperature(SST) on tropical cyclone(TC) intensity.The results reveal that the relative SST within a radius of 2-3 times the radius of maximum wind contributes positively and greatly to TC intensity,while the remote SST far away from the TC center could reduce storm intensity.The change of air-sea temperature and moisture differences may be the reason why TC intensity is more sensitive to the relative rather than the absolute SST.As the inflow air moves toward the eyewall,warmer(colder) remote SST can gradually increase(decrease) the underlying surface air temperature and moisture,and thus decrease(increase) the air-sea temperature and moisture differences,which lead to less(more) energy fluxes entering the eyewall and then decrease(increase) the TC intensity and make it less sensitive to the absolute SST change.Finally,with all the related dynamic and thermodynamic processes being taken into account,a schematic diagram for the effects of relative SST and absolute SST on TC intensity is proposed.  相似文献