基于地理探测器的合肥市热岛效应影响因素分析

地表温度是城市热岛效应的重要指标。本文利用合肥市2018年4月10日的Landsat-8 OLI影像数据,经过预处理后,采用大气校正法反演地表辐射温度,并提取研究区域的归一化差分植被指数(NDVI)、归一化差分水体指数(NDWI)。通过地理探测器模型,探测地表温度和海拔、NDVI、NDWI等因子之间的影响关系。结果表明：合肥市存在热岛效应。通过分析地理探测器模型的探测结果可知：从单一因子探测角度分析,影响合肥市地表温度的主导因子为NDVI和NDWI;从两因子交互作用影响角度分析,NDVI对因子交互作用的影响最强。研究结果有利于分析合肥市热岛效应的影响因素,为城市规划、生态环境保护提供科学依据。     

基于数理统计方法的闪电气候研究

基于广东省1999—2015年闪电定位系统数据,利用数理统计方法得出广东省闪电气候年际变化特征、季节变化特征、月变化特征,利用最小二乘法得到闪电密度气候变化趋势系数和年、季节的气候倾向率。利用Matlab来对广东省1999—2013年的雷暴日进行分析,得出其年际周期变化规律,最后采用EOF方法,借助Arc GIS平台得出广东省闪电密度空间向量场分布图。结果表明:由1999—2015年,广东全省的地闪密度总体趋势是逐渐增加,闪电日数最多的月份集中在6—8月(夏季);雷暴日存在变化具有周期性、规律性,分别有13～16 a,7～11 a、2～6 a 3种不同尺度的周期;闪电密度空间分布特征主要有一致型、局部型、纬向型和经向型4种类型。     

武汉东湖不同营养型子湖的水生生物与水域功能

于１９９１－１９９３年研究了武汉东湖４个营养型不同的子湖中水生生物与水域功能,表明各子湖之间各类水生生物的生态特征存在明显差异,茶港湾的ＨＢＣ和ＦＣ的数量,藻类的细胞密度和初级生产量,浮游动物和底栖动物的个体密度等均居４个子湖之首,其水质已达到了超富营养水平,将该湖区的作为污水天然净化区进行管理,可望对东湖的主体湖区起到缓冲和保护作用,郭郑湖的水质状况仅次于茶港湾湖区,处于富营养阶段,该湖区多项生     

塔中地区卡1三维区块奥陶系鹰山组台内滩的地震相特征与分布

塔里木盆地塔中地区奥陶系鹰山组是海相碳酸盐岩油气勘探的有利目标层位。为查明塔中地区卡1三维区块鹰山组台内滩储层的空间分布,基于大量的岩心、钻井、地震资料,通过井震对比,分析台内滩的地震反射特征,并在此基础上预测卡1区块内鹰山组台内滩的分布。研究认为,台内滩内部多具有高频无序反射,振幅的强弱变化明显,且不均匀,两翼地层厚度有较明显的变化,与相邻层位岩性有明显差异;在顶面和底面多具有宽、缓的透镜状或丘状地震反射波外形,台内滩附近的围岩,较明显地超覆或披覆在台内滩之上。在精细解释三维地震资料的基础上,利用地震属性,对鹰山组古地貌进行了恢复,预测卡1三维区块奥陶系鹰山组的台内滩有利发育区,为区内高能滩相储集层的评价奠定基础。     

长江流域沿江镉异常示踪与追源的战略与战术

正在进行的多目标地球化学调查成果显示,长江流域存在全流域的Cd异常。长江流域Cd异常示踪与追源研究的长期目标是查明长江流域沿江各主要支流(汇水面积大于5000km^{2)Cd等重金属元素的物质来源、迁移形式和输入/输出通量、分辨自然源与人为源各自所占份额,建立沿江各支流Cd时空演化模型,监测它的未来发展趋势,对潜在生态效应进行预警预测;短期目标是针对Cd异常的重点地区,如长江源头、三峡库区、湘江流域、江淮流域、长江三角洲及流域内的4大淡水湖泊,查明Cd异常的来源,重建Cd异常形成的地球化学记录,评估可预见的将来(如10～50年)Cd异常的生态效应。}     

Acidity of Aerosols during Winter Heavy Haze Events in Beijing and Gucheng,China

We investigated the acidity and concentrations of water-soluble ions in PM_2.5 aerosol samples collected from an urban site in Beijing and a rural site in Gucheng, Hebei Province from November 2016 to January 2017 to gain an insight into the formation of secondary inorganic species. The average SO₄^2–, NO₃^–, and NH₄⁺ concentrations were 8.3, 12.5, and 14.1 μg m^–3, respectively, at the urban site and 14.0, 14.2, and 24.2 μg m^–3, respectively, at the rural site. The nitrogen and sulfur oxidation ratios in urban Beijing were correlated with relative humidity (with correlation coefficient r = 0.79 and 0.67, respectively) and the aerosol loadings. Based on a parameterization model, we found that the rate constant of the heterogeneous reactions for SO₂ on polluted days was about 10 times higher than that on clear days, suggesting that the heterogeneous reactions in the aerosol water played an essential role in haze events. The ISORROPIA II model was used to predict the aerosol pH, which had a mean (range) of 5.0 (4.9–5.2) and 5.3 (4.6–6.3) at the urban and rural site, respectively. Under the conditions with this predicted pH value, oxidation by dissolved NO₂ and the hydrolysis of N₂O₅ may be the major heterogeneous reactions forming SO₄^2– and NO₃^– in haze. We also analyzed the sensitivity of the aerosol pH to changes in the concentrations of SO₄^2–, NO₃^–, and NH₄⁺ under haze conditions. The aerosol pH was more sensitive to the SO₄^2– and NH₄⁺ concentrations with opposing trends, than to the NO₃^– concentrations. The sensitivity of the pH was relatively weak overall, which was attributed to the buffering effect of NH₃ partitioning.     

Sensitivity of carbon budget to historical climate variability and atmospheric CO2 concentration in temperate grassland ecosystems in China

Chinese temperate grasslands play an important role in the terrestrial carbon cycle. Based on the parameterization and validation of Terrestrial Ecosystem Model (TEM, Version 5.0), we analyzed the carbon budgets of Chinese temperate grasslands and their responses to historical atmospheric CO₂ concentration and climate variability during 1951–2007. The results indicated that Chinese temperate grassland acted as a slight carbon sink with annual mean value of 7.3 T?g C, ranging from -80.5 to 79.6 T?g C yr^-1. Our sensitivity experiments further revealed that precipitation variability was the primary factor for decreasing carbon storage. CO₂ fertilization may increase the carbon storage (1.4 %) but cannot offset the proportion caused by climate variability (-15.3 %). Impacts of CO₂ concentration, temperature and precipitation variability on Chinese temperate grassland cannot be simply explained by the sum of the individual effects. Interactions among them increased total carbon storage of 56.6 T?g C which 14.2 T?g C was stored in vegetation and 42.4 T?g C was stored in soil. Besides, different grassland types had different responses to climate change and CO₂ concentration. NPP and R_H of the desert and forest steppes were more sensitive to precipitation variability than temperature variability while the typical steppe responded to temperature variability more sensitively than the desert and forest steppes.     

农业气象信息资源开发与共享技术研究

本专题为国家科技攻关计划项目--农业信息技术研究之第2课题"农业信息资源开发与共享技术研究"的第2专题(2001BA513B02-2).专题旨在针对目前农业气象服务中面向政府的宏观决策服务和常规书面报告的服务形式已不能满足信息时代政府、农民对农业生产气象信息需求的状况,研制基于WebGIS的农业气象信息共享技术,开发全国农业气象信息网络化服务系统,使农业气象信息能直接、迅速、便捷、有效地传输到农业生产第一线,为农业生产服务.     

地震计远程监控功能接口的实现

提出了一种适用于地震计远程监控功能接口的实现方式,扩充了地震数据采集器的应用。