湘西北2008年初持续冰雪灾害及对椪柑影响分析     

彭洁  叶成志  吕昆坤  邹锦明  胡雪媛 《气象科学》2009,29(6)

2008年初湘西北出现了自1956年有气象记录以来低温持续时间最长、冰冻范围最大、强度最强的一次低温雨雪冰冻天气过程,罕见的特大冰冻灾害给当地支柱产业之一的椪柑生产带来严重影响.本文从天气学和农业气象学角度出发,对低温雨雪造成的椪柑冻害及椪柑成果的贮藏、销售影响进行了详细评估,旨在为湘西北椪柑生产恢复与制定防灾减灾措施提出科学依据.  相似文献   

利用冰雷达诊断南极冰盖底部环境的研究综述          下载免费PDF全文

杨树瑚  顾祈明张云崔祥斌  唐学远 《极地研究》2016,28(2):277-286

现今南极冰盖底部的环境对冰盖的动力演化有着重要的影响,准确的冰盖底部环境信息有利于更加准确地模拟南极冰盖的起源、发展以及未来的演化。采用无线电回波技术,可有效地对冰盖进行探测。通过定量地处理雷达波在冰盖内部的介电衰减,可以获取冰盖底部的反射率,从而对冰盖底部环境,特别是冰下水文环境进行诊断。综述了雷达波在冰盖内部衰减处理的三种方法,分析了它们的适用性及局限性,并对这些方法应用于诊断冰盖底部的环境以及方法本身可能的改进进行了讨论。  相似文献   

基准站的网形对机载差分GPS定位测速结果的影响     

宋雪源  马国元  贾赞杰  史线龙  孙中豪 《测绘信息与工程》2011,36(4):28-31

采用实测数据,进行了事后处理比较与分析,讨论了单基站差分和多基站差分的关系,分析了基准站的网形对多基站差分的影响,得出了一些有益的结论。  相似文献   

基于多尺度预处理的GPS/SINS组合导航系统     

李廷军  林雪原 《武汉大学学报(信息科学版)》2011,(1):6-9,13

基于多尺度分析的思想,以离散小波变换为工具,利用小波对惯性元件输出的信息进行并行阈值消噪以削弱惯性元件误差对SINS及组合系统性能的影响;然后,对GPS输出的信息进行并行多尺度预处理,并结合传统的Kalman滤波方法,对系统进行综合滤波;将上述方法引入到GPS/SINS组合导航系统中,利用实测数据进行验证,并给出了基于不同方法的大量实验曲线。实验结果表明,该方法可以有效削弱惯性元件以及GPS误差对系统的影响,提高了GPS/SINS组合导航系的精度和可靠性。  相似文献   

风廓线雷达资料在台风苏拉登陆过程中的应用初探   总被引：2，自引：0，他引：2  

汪学渊  李栋  任雍  陈孝腔  朱会芸 《气象》2013,39(11):1431-1436

为了研究风廓线雷达在台风天气过程预报中的作用,对2012年8月2—4日在福建秦屿镇登陆的台风苏拉天气过程统计分析,结果表明：风廓线雷达在台风苏拉登陆期间4 km以上高空有效数据获取率明显提高,确定风廓线雷达的有效探测高度为4.8 km;通过信噪比和垂直速度数据统计分析出台风登陆前后带来间歇性的降雨,而台风眼登陆主要表现为无降水天气,仅有少量的降雨,这一结论进一步在小时降雨量统计中得到验证;通过水平风速数据统计分析出台风登陆前后在有效探测高度内水平风速在25 m·s-1左右,而台风眼登陆水平风速在0~3 m·s-1; 统计结果与台风登陆物理过程相吻合。  相似文献   

The Influences of Various Factors and Interest Demands on Linpan Landscape Evolution in the Chengdu Plain: A Qualitative Study based on Oral Histories     

ZHOU Lian  HUANG Xueyuan  ZHANG Lei 《资源与生态学报(英文版)》2023,14(1):124-136

Traditional rural homegarden agroforestry systems in the Chengdu Plain of China are often referred to as “Linpan” in Chinese, which integrates the landscape of ecological functions and human production activities. In recent years, due to the influences of urbanization and the aging population, the Linpan landscape has changed dramatically. Clarifying the factors which influence Linpan landscape evolution is a critical way to improve rural landscape renovation. Through oral history interviews, the deep-seated factors driving the evolution of the Linpan landscape form from 1949 to 2020 are explored using the grounded theory. The results show that in the process of Linpan landscape evolution, beneficiary groups, the material basis, and cultural characteristics are the prerequisites for changing the Linpan settlement landscape. The demand of production and life and government-led behavior are the two main influencing factors, and landscape change is the final result. The demand of production and life from the residents is the primary internal driving force of landscape change, while government-led behavior is the main external driving force of settlement development and evolution. The nature of the main driving forces behind the evolution of the Linpan landscape in the Chengdu Plain can be divided into three stages. (1) From 1949 to 1980, it was characterized as a balancing of government forces and social forces. (2) From 1981 to 1993, it was characterized by social forces suppressing government forces. (3) From 1994 to 2020, it was characterized as a stalemate between the government and social forces. From the perspective of the evolution of the Linpan settlement landscape, the traditional Linpan form and settlement layout have been unable to meet the new requirements of the rural social and economic transition period. They are facing the challenges of rural reconstruction and rural revitalization. In the future, village and town planning and the design of new settlements need to comprehensively consider the demands of different interest groups.  相似文献   

Distribution of phosphine in the offshore area of the Southwest Yellow Sea,East Asia     

Yuning Hong  Jinju Geng  Song Qiao  Lili Ding  Xueyuan Gu  Xiaorong Wang  Dietmar Glindemann  Hongqiang Ren 《Marine Chemistry》2010,118(1-2):67-74

Phosphine is a natural gaseous compound in the phosphorus biogeochemical cycle. This paper studies the spatial and temporal distributions of matrix-bound phosphine (MBP) and gaseous phosphine in the offshore area of the Southwest Yellow Sea, East Asia. The results show that MBP concentrations in marine surface sediments range from 0.69 ± 0.06 ng/kg (dry) to 179 ± 29 ng/kg (dry). Higher seasonal MBP concentrations in sediments are found in fall than in spring or winter in most sites. High MBP contents are observed in two fish-breeding areas. MBP concentrations decrease with distance to the coast, except in the southeast of the sampling area. MBP levels in marine sediments are found to be higher than those at several other places: freshwater sediments and soil, except eutrophic lakes. Gaseous phosphine contents in fall range from 0.14 ± 0.00 ng/m³ to 9.83 ± 0.97 ng/m³. No correlation is observed between MBP and gaseous phosphine.  相似文献   

基于遥感与GIS的矿山地质环境时空演变分析——以东胜矿区为例     

李学渊  赵博  陈时磊  赵颖旺  边凯 《国土资源遥感》2015,(2):167-173

煤矿开采将不可避免地产生地质环境问题。以东胜矿区2007年Quick Bird遥感影像和2012年World View2影像为数据源,通过提取矿山地质环境现状信息,计算矿山地质环境类型时空数据的变化幅度、变化速度及转移矩阵等,揭示不同矿山地质环境类型的时间变化过程;以采矿权为空间单元,通过计算各类矿山地质环境的年均增幅与综合动态度,描述其空间演变趋势。结果表明:随着东胜矿区开采规模持续扩大,不同矿山地质环境类型的面积逐年增加且增幅各异,由"污染"(采坑、排土场及积水区)向"治理"(恢复治理区和工业广场)转移的趋势显著;尽管矿区地质环境已得到足够重视,并呈现西北区域恢复治理优于东南区域的特点,但"治理"力度总体上慢于"污染"程度,仍不利于可持续发展。  相似文献   

广西资源县某萤石矿矿山地质灾害危险性评估及防治对策          下载免费PDF全文

蒋剑  郑剑锋  陈雪源 《山东国土资源》2015,31(1):50-54

以广西资源县某萤石矿山为例,重点介绍矿山地质灾害危险性评估的分析思路及基本方法,并提出有效的防控对策。在了解矿山基本情况和查明矿山地质环境背景的基础上,综合采矿场地形及工程活动特征,对矿山地质灾害进行现状评估和预测评估,并提出了相应的防治对策。  相似文献   

Analysis of the simulated different-class Meiyu precipitation and associated circulation by the BCC_AGCM2.0.1     

Ying Huang  Yaocun Zhang  Anning Huang  Xueyuan Kuang  Danqing Huang  Yonghong Yao  Lujun Zhang 《Theoretical and Applied Climatology》2015,120(3-4):631-641

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