贵阳市空气质量预报方法与效果检验     

宋丹  夏晓玲  何玉龙  张蕾  杜正静 《气象与环境科学》2019,42(1):93-100

2012年环境保护部发布的《环境空气质量标准》实施后,贵阳市空气质量状况发生了变化。利用贵阳市空气质量指数和常规气象要素等资料,分析空气质量特征及其与气象要素的关系,通过多元线性逐步回归和BP神经网络方法,分季节建立空气质量指数预报模型,并同CUACE模式进行对比检验。结果表明:近3年贵阳市空气质量状况良好,优良天数增多,污染天数减少且污染天气多出现在冬季,首要污染物为PM_2.5、PM₁₀和O_3;各季相关因子不同,但主要与相对湿度和风速有关;两种模型预报效果均表现为夏季评价最高,等级TS评分超过85%,指数准确率近99%,冬季预报效果相对最差,TS评分接近或达到70%,指数准确率超过或接近80%,而春、秋季效果指标差距不大;对2015—2016年AQI的预报效果回归模型的优于CUACE模式的,TS评分和预报准确率分别相差16.2%和20.0%。  相似文献   

Application of Partial Least Squares Regression in Multimodal Integrated Forecasting of Water Vapor and Surface Air Temperature   总被引：1，自引：1，他引：0  

Jiangfeng Li  Xiaojun Cai  Wen Wang  Qianwen Li  Yansen Lei 《地球科学进展》2018,33(4):404-415

The use of a new multi model integration method of Partial Least Squares regression (PLS) can completely eliminate the multicollinearity features to improve multi model’s integrated forecasting results of the humidity and temperature. Based on the four centers’ ensemble forecast results, namely, the European Center for Medium-Range Weather Forecasts (ECMWF), Chinese Meteorological Administration (CMA), the Japan Meteorological Agency (JMA) and the UK Met Office (UKMO), we built a 2012 multi mode (25°~60°N, 60°~150°E) 24 ~168 hours forecast time (interval 24 hours) multi model for humidity and temperature and used the four methods, like ensemble average (BREM) for eliminating the deviation, a simple set of average (EMN), Super Ensemble (SUP) and Partial Least Squares regression (PLS) for ground temperature multi model integration. We used the Root-Mean-Square Error (RMSE) and anomaly correlation coefficient (cor) to determine the effect of more modes of integration and to predict a short course of cold. The two prediction results showed that the Partial Least Squares regression (PLS) was the best multi model integrated method, more superior than the other three single modes and compared with the other three methods, it showed better prediction performance, which has certain value and application prospect.  相似文献   

基于多元回归模型的斜坡影响因子分析          下载免费PDF全文

覃强  董建辉 《探矿工程》2018,45(8):102-106

目前,对斜坡影响因子进行量化的评价方法均有各自的局限性。在基于监测数据的基础上提出多元回归模型进行量化斜坡影响因子的方法。通过将确定的斜坡影响因子与回归模型的融合,在一定程度解决了斜坡稳定性评价过程中影响因子的选择和量化的问题,有利于以后对斜坡的认识,建立准确的斜坡稳定性分析模型。最后,将模型应用于某水电站水库堆积体斜坡,对该斜坡的影响因子进行量化,最后分析汶川地震前后的影响因子变化。  相似文献   

Identification of landslide susceptibility zones in Gish River basin,West Bengal,India     

Tirthankar Basu  Swades Pal 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2018,12(1):14-28

The occurrence of landslide in the hilly region of Darjeeling during monsoon season is a matter of serious concern. Every year this natural hazard damages the major roads at several places and thus disrupts the transport and communication system in this region. This paper tries to prepare a landslide susceptibility zone (LSZ) map for the Gish River basin. A total number of 16 spatial parameters have been taken for this study and these are categorised under six factor clusters or groups for example, triggering factors, protective factor, lithological factors, morphometric factors, hydrological factors and anthropogenic factors. The LSZ map is prepared by integrating all the parameters adopting the weighting base as logistic regression. The landslide susceptibility map shows that nearly 9.11% of the area falls under the very high landslide-susceptible zone while 40.28% of the area of the total basin lies under the very low landslide-susceptible zone. The landslide-susceptible model is validated through the receiver operating characteristic curve. This curve shows 86% success rate in defining landslide-susceptible zones and 83.40% prediction rate for the occurrence of landslides. The spatial relationship between the landslide susceptibility model and other factors’ groups shows that the morphometric factors’ cluster (mainly slope) is the focalone for the determination of landslide-susceptible zone.  相似文献   

中国雾霾分布及其组成相关性分析   总被引：1，自引：0，他引：1  

贾艳红  陆赛娣  冯小莉  冒赟  申玲丽 《测绘与空间地理信息》2015,(12):9-12

雾霾天气由于其对人体健康及交通能见度的极大影响而受到广泛关注。在收集相关污染物与气象数据基础上,基于GIS技术及最小二乘法和地理加权回归模型分析了我国2014年1月雾霾空间分布特征及其组成要素的相关性。研究表明,2014年1月我国各省会城市基本都受到雾霾影响,其中华北地区最为显著,华东、华南沿海城市具有一定的相似性;西南部地区大部雾霾污染明显小于其他地区。从雾霾物质组成上看,PM_(2.5)与PM_(10)、CO、NO_2和SO_2之间存在微妙关系,随着其他污染物的增加,PM_(2.5)数值也会随之增大,其中PM_(10)和CO对PM2.5的影响是显著的。从研究方法上看,利用地理加权回归建模方法对雾霾及其组成成份相关性研究的效果(84%)略好于最小二乘法的分析效果(82.59%)。本研究可为了解雾霾空间分布特征及分析其相关影响因素提供参考。  相似文献   

Geographically-weighted regression analysis of percentage of late-stage prostate cancer diagnosis in Florida     

《Applied geography (Sevenoaks, England)》2015

This study assessed spatial context and the local impacts of putative factors on the proportion of prostate cancer diagnosed at late-stages in Florida during the period 2001–2007. A logistic regression was performed aspatially and by geographically-weighted regression (GWR) at the nodes of a 5 km spacing grid overlaid over Florida and using all the cancer cases within a radius of 125 km of each node. Variables associated significantly with high percentages of late-stage prostate cancer included having comorbidities, smoking, being Black and living in census tracts with farmhouses. Having private or public insurance, being married or diagnosed in a for-profit facility, as well as living in census tracts with high household income reduced significantly this likelihood. Geographically-weighted regression allowed the identification of areas where the local odds ratio is significantly different from the ratio estimated using aspatial regression (State-level). For example, the local odds ratios for the comorbidity covariates were significantly smaller than the State-level odds ratio in Tallahassee and Pensacola, while they were significantly larger in Palm Beach. This emphasizes the need for local strategies and cancer control interventions to reduce the percentage of prostate cancer diagnosed at late-stages and ultimately eliminate health disparities.  相似文献   

新经济地理学视角下中国纺织业区际转移的粘性分析     

耿文才 《地理研究》2015,34(2):259-269

如何破除产业区际转移粘性,实现区域经济协调发展已成为近年来国内研究的热点问题。基于新经济地理学视角,综合运用区位熵、产业集聚变动指数和面板数据的门限回归方法,对2000-2010年中国纺织业转移的时空特征及区际转移产生粘性的原因进行了研究。结果表明,尽管东部纺织业已出现明显的转移趋势,但就其跨区向中西部转移而言仍具有很强的粘性,其原因在于:1纺织业对本地市场具有较强的依赖性,因而在市场接近效应的作用下东部纺织业向中西部地区的转移存在一定的市场阻力;2纺织业集聚的外部规模效应仍在增强,特别是东部部分省份的纺织业未来仍有较强的集聚动力;3东部由于其特定区位优势和经济发展非均衡的特点为该地区纺织业在其内部省份间的调整提供了回旋余地。  相似文献   

企业海外集群与新晋企业对外直接投资区位选择——基于浙江省微观企业数据   总被引：3，自引：2，他引：1  

余官胜  林俐 《地理研究》2015,34(2):364-372

企业对外直接投资海外集群和区位选择均是当前理论和政策的热门话题,着眼于研究两者之间的关系。由于东道国国别经济存在较大的差异,因此中国企业在对外直接投资区位选择过程中较为注重特定的国别状况,东道国经济规模、人均收入、贸易开放、资源条件等因素均构成了企业对外直接投资区位选择的影响因素,此外本国企业在东道国的海外集群也是企业对外直接投资区位选择决策的不可忽视因素。利用浙江省微观企业数据构造二值选择模型,并使用浙江省在某东道国的对外直接投资项目数度量在该国的海外集群状况,研究发现:企业海外集群是东道国吸引新晋企业对外直接投资的重要区位优势,并且这种区位优势在资源越丰富和市场规模越大的国家发挥的作用也越大。为了消除回归的内生性问题,使用地理距离作为企业海外集群的工具变量,通过二阶段二值选择模型得出了类似的结论;并且通过分样本实证研究发现无论在发达国家还是发展中国家东道国,企业海外集群吸引新晋企业对外直接投资的正向影响均保持不变。结果说明了企业对外直接投资海外集群具有自我延续性,也反映了信息在企业对外直接投资区位选择中的重要性。  相似文献   

广州市三个圈层社区居民通勤碳排放特征——以都府小区、南雅苑小区和丽江花园为例     

黄晓燕  刘夏琼  曹小曙 《地理研究》2015,34(4)

低碳城市已成为应对全球气候变化和促进人与自然和谐相处的重要研究领域,但从微观层面探讨城市居民通勤碳排放特征和影响因素的研究较为缺乏.利用对广州市不同圈层社区的问卷调查数据,对其通勤碳排放进行测算,采用分等定级和洛伦兹曲线分析社区间、社区内、个体间的分异,并建立了基于多元回归的社区居民通勤碳排放的影响模型.结果显示:社区居民通勤碳排放较符合“60-20”规律(温室气体排放最多的20％的人排放了总量的60％).中心区和边缘区的通勤碳排放不均等性更大;不同个人、家庭和通勤属性的通勤者的碳排放量存在较大差异;通勤距离、出行交通方式、每天的通勤往返次数、个人的工作月收入和所在街道的人口密度对家庭通勤碳排放有显著影响.  相似文献   

农户土地转出行为调查与分析   总被引：1，自引：0，他引：1  

付凯  杨朝现  信桂新  程飞  邵丽亚 《地域研究与开发》2015,(3)

以成渝城乡统筹区农地转出户为研究对象,根据农地转出率的大小将农户分为完全转出户、高度转出户和基本转出户,运用多元线性回归模型和OLS回归模型对农户农地转出行为的影响因素及收入效应进行分析。研究结果表明:成渝城乡统筹区农地转出户的农地转出率不尽相同,完全转出户、高度转出户和一般转出户并存,农地转出方式和转出对象虽然存在多样性,但农地仍以小规模分散转出为主;稳定的非农收入、政府的积极推动以及合理的农地转出价格促进了农户农地转出率的提高,而土地细碎化和较多的家庭常年务农人口数量在一定程度上阻碍了农户农地转出行为;农户农地转出是一种理性决策行为,农地转出率越高,农户的收入效应就越明显,收入由多至少依次为完全转出户、高度转出户和一般转出户。  相似文献