基于决策树的洪泽湖湿地信息提取     

张楼香  阮仁宗 《测绘与空间地理信息》2015,(2):87-91

湿地是地球的重要组成部分,快速而准确地提取湿地信息,是湿地动态监测和可持续发展的一项基础而重要的工作.以洪泽湖淡水湿地为研究对象,采用2006年8月19日的Landsat5 TM遥感影像为数据源,采用经K-T变换光谱增强后的数据及利用灰度共生矩阵分析影像第一主成分的纹理统计量作辅助分类变量,基于地物光谱特征、纹理特征和形状特征,运用决策树分类法提取洪泽湖湿地植被信息,将其分类结果与最大似然法的分类结果进行比较.结果表明:1)洪泽湖地区的湿地植被比较丰富,面积约占全湖的10.74％,其中以浮水植物为主.2)基于决策树的分类结果的精度有了明显的提高,总精度由77.33％提高到86.33％,Kappa系数由0.7292提高到0.8354,证明基于决策树分类方法是提取淡水湿地植被信息的有效手段.  相似文献   

国家级决策气象服务需求变化分析          下载免费PDF全文

梁科  王亚伟  何孟洁  喻迎春 《气象与减灾研究》2020,43(3):210-215

为进一步了解国家级决策气象服务需求变化情况,通过调查问卷方式,收集国家级决策气象服务用户对决策气象服务工作的有关意见,结合2018年决策气象服务具体数据,分析党中央和国务院机构调整后,决策对象对气象灾害的关注特点以及对气象服务需求的变化。据此提出决策气象服务供给侧改革建议,1） 调整决策气象服务业务流程,优化决策气象服务产品内容。2） 推动发展新一代气象服务信息系统,提高决策气象服务技术能力。3） 推动建立与重点部门的沟通对接机制,为重点部门提供定制化、模块化决策气象服务信息支撑,实现用户向制作方的反馈机制。  相似文献   

基于灰区间真值的群体决策方法及应用     

巩在武  郭崇兰  周显信 《南京气象学院学报》2013,5(2):171-177

研究了灰区间偏好的群体决策问题.在专家灰区间偏好群体意见集结过程中,常规的灰区间运算会产生决策信息的失真.为了避免这一缺陷,首先引入了灰区间调节参数的概念,通过建立求解调节参数的二次规划模型,确定专家灰区间判断的真值.建立了专家客观权重求解的二次规划模型,并给出了专家客观权重的最优解.此外,从另外一个角度同时考虑调节参数与客观权重,建立求解灰区间真值与专家客观权重的群体最优决策模型.气象敏感性行业专家群体评估决策的算例表明,决策策略是有效的.  相似文献   

胡杨树轮δ13C记录的艾比湖地区夏季最高温度变化     

尚华明 《沙漠与绿洲气象(新疆气象)》2013,7(5):7-13

摘要：艾比湖是新疆北部生态环境最为敏感和脆弱的地区,这里分布的大片长龄胡杨是过去气候变化良好的记录体。本文利用艾比湖东岸的胡杨树轮资料,分析其宽度和稳定碳同位素组成,建立了树轮宽度年表和δ^13C序列,并对δ^13C序列进行了校正处理。树轮参数的气候意义分析表明胡杨树轮宽度所含的气候信息较少,而树轮δ^13C校正序列与精河夏季高温显著负相关,为荒漠平原区树轮气候研究提供了新的资料。研究区夏季的高温超过了光合作用的适宜温度,降低光合作用速率（A）,而地下水埋深较浅,叶片气候导度（g）并没有因受到水分条件限制而减小,在以上两个因素的共同作用下,叶片内部二氧化碳浓度（Ci）升高,导致胡杨δ^13C与夏季高温负相关关系。建立了胡杨树轮δ^13C校正序列与精河夏季高温的转换方程,方差解释量为33．0％。重建的精河145a来夏季高温序列反映了这一地区气候变暖的趋势,其升温的幅度高于北半球夏季升温幅度,但二者冷暖阶段变化并不完全一致。  相似文献   

A CER discounting scheme could save climate change regime after 2012     

RAE KWON CHUNG 《Climate Policy》2013,13(2):171-176

We can generate a net global GHG emission reduction from developing countries (in an UNFCCC term, non-Annex 1 Parties) without imposing targets on them, if we discount CERs generated from CDM projects. The CER discounting scheme means that a part or all of CDM credits, i.e., CERs, made by developing countries through unilateral CDM projects will be retired rather than sold to developed countries to increase their emissions. It is not feasible to impose certain forms of target (whether sectoral or intensity targets) on non-Annex 1 whose emission trend is hard to predict and whose industrial structure is undergoing a rapid change.

Instead of imposing targets (a command and control approach), we should apply market instruments in generating a net global emission reduction from non-Annex 1. Since April 2005 when the first unilateral CDM was approved by the CDM Executive Board, CDM has been functioning as a market mechanism to provide incentives for developing countries to initiate their own emission reduction projects. As CDM is the only market mechanism engaging developing countries in the Kyoto Protocol, we should try to re-design CDM so that it can generate net global emission reductions by introducing the idea of discounting CERs. But in order to produce meaningful GHG emission reductions by discounting CERs, the project scope of CDM has to be expanded by relaxing project additionality criteria while maintaining strict technical additionality criteria. Agreeing on the CERs Discounting Scheme will have a better political chance than agreeing on imposing emission reduction targets on developing countries.  相似文献   

协调决策表的规则提取     

朱六兵  蒋朝哲  高晓琴  杨斌 《成都信息工程学院学报》2006,21(5):686-689

对数据的性质、数据之间的关系进行了讨论，并由此对决策表进行了分类。研究了协调决策表所需要的必要的数据个数，这对数据采集有着实际的指导意义和经济意义。讨论了协调决策表的数据约简，并证明其不影响进一步的属性约简和规则提取。基于数据的协调性，对协调决策表的属性约简进行了研究，并提出了一种规则提取方法。最后，用实例验证了该方法的有效性。  相似文献   

TREE INVASION IN MEADOWS OF LASSEN VOLCANIC NATIONAL PARK,CALIFORNIA*     

Alan H. Taylor 《The Professional geographer》1990,42(4):457-470

The causes of tree invasion into meadows in Lassen Volcanic National Park were investigated by dating invasive trees and associating age structure patterns with regional variations in fire history, grazing, and climate change. Massive invasion was associated primarily with cessation of livestock grazing and burning between 1905 and 1933, but climatic change may also have contributed. Maintenance of meadows may require continued use of unnatural processes due to uncertainties about pre-European fire regimes and other resource considerations.  相似文献   

水资源优化配置决策支持系统中的软件集成方法     

王文林  王文科  王钊  高进龙 《地球科学与环境学报》2001,23(2):68-70

根据水资源优化配置决策支持系统的开发实践，分析了多平台软件的集成问题，给出了多平台软件集成中用户数据及控制信息的相互传递方法。  相似文献   

响应矩阵技术在唐马试验场地下水管理中的应用     

王恩志 《地球科学与环境学报》1989,(2)

响应矩阵技术是解决地下水管理问题的方法之一,它是通过表征系统结构特征的单位脉冲响应函数来求得由抽水产生的水位分布,并以此作为线性规划的约束条件建立地下水系统的水动力管理模型。本文造过对唐马试验场水文地质条件的分析,建立数学模型并将其分解和离散,对渗流区内各井点作用一单位脉冲来形成响应矩阵,建立水动力管理模型和水位预报方程,对本区未来地下水开采进行优化决策。  相似文献   

Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre‐Polar Urals,northeast European Russia     

Seija Kultti  Minna Vliranta  Kaarina Sarmaja‐Korjonen  Nadia Solovieva  Tarmo Virtanen  Tommi Kauppila  Matti Eronen 《第四纪科学杂志》2003,18(6):503-520

This study investigated Holocene tree‐line history and climatic change in the pre‐Polar Urals, northeast European Russia. A sediment core from Mezhgornoe Lake situated at the present‐day alpine tree‐line was studied for pollen, plant macrofossils, Cladocera and diatoms. A peat section from Vangyr Mire in the nearby mixed mountain taiga zone was analysed for pollen. The results suggest that the study area experienced a climatic optimum in the early Holocene and that summer temperatures were at least 2°C warmer than today. Tree birch immigrated to the Mezhgornoe Lake area at the onset of the Holocene. Mixed spruce forests followed at ca. 9500–9000 ¹⁴C yr BP. Climate was moist and the water level of Mezhgornoe Lake rose rapidly. The hypsithermal phase lasted until ca. 5500–4500 ¹⁴C yr BP, after which the mixed forest withdrew from the Mezhgornoe catchment as a result of the climate cooling. The gradual altitudinal downward shift of vegetation zones resulted in the present situation, with larch forming the tree‐line. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献