基于最小二乘配置法的沿海高程异常模型建立研究

陆海统一高程基准的关键是高程异常模型的建立,本文采用既考虑函数模型中非随机变量同时考虑随机部分的最小二乘配置法进行高程异常的拟合推估,建立区域高程异常模型,并与常用方法进行比较分析.以江苏沿海高程异常模型建立为例,研究得出不同拟合方法的拟合精度和残差图各有特点,最小二乘配置法的外部符合精度最高.     

Seasonal changes in nitrogen and phosphorus transport in the lower Changjiang River before the construction of the Three Gorges Dam

Water and sediment samples were collected at Datong from June 1998 to March 1999 to examine seasonal changes in the transports of nitrogen (N) and phosphorus (P) from the Changjiang River (Yangtze River) to the East China Sea (ECS). Dissolved inorganic nitrogen (DIN; dominated by nitrate) concentration exhibited small seasonality, and DIN flux was largely controlled by water discharge. Dissolved inorganic phosphorus (DIP) concentration was inversely correlated with water discharge, and DIP was evenly delivered throughout a year. The transports of DIN and DIP from the Changjiang River were consistent with seasonal changes in nutrient distributions and P limitation in the Changjiang Estuary and the adjacent ECS. Dissolved organic and particulate N (DON and PN) and P (DOP and PP) varied parallel to water discharge, and were dominantly transported during a summer flood. The fluxes of DOP and particulate bioavailable P (PBAP) were 2.5 and 4 times that of DIP during this period, respectively. PBAP accounted for 12–16% of total particulate P (PP), and was positively correlated with the summation of adsorbed P, Al–P and Fe–P. Ca–P, the major fraction of PP, increased with increasing percent of CaCO₃. The remobilization of riverine DOP and PBAP likely accounted for the summer elevated primary production in DIP-depleted waters in the Changjiang Estuary and the adjacent ECS. The Changjiang River delivered approximately 6% of DIN (1459 × 10⁶ kg), 1% of DIP (12 × 10⁶ kg), and 2% of dissolved organic and particulate N and P to the totals of global rivers. The construction of the Three Gorges Dam might have substantially reduced the particulate nutrient loads, thereby augmenting P limitation in the Changjiang Estuary and ECS.     

基于GIS的水资源查询统计软件系统设计与实现

地理信息系统(GIS)因为其强大的空间数据处理能力,为水资源管理提供了一个新颖、高效、具有良好可视化效果的管理与应用工具.在与水资源管理专业人员的多次调研、分析基础上,我们基于自主产权版本的Geo-Windows(地学之窗)GIS软件平台开发了一套水资源管理信息试验系统.该系统充分发挥了地理信息系统所具有的地图图面直观、反应快捷、易操作、查询方便、分析功能强大等功能,使水资源管理工作更趋完善,更具有合理性和科学性,可以为领导的辅助决策提供依据.     

三疣梭子蟹溞状Ⅰ期幼体的饥饿实验

通过观察不同饥饿胁迫处理对三疣梭子蟹(Portunus trituberculatus)溞状Ⅰ期幼体变态和发育的影响,研究了其"营养储存饱和点"(the point of reserve saturation,PRS)和"不可恢复点"(the point of no return,PNR)现象的发生情况.结果表明:以轮虫为饵料,三疣梭子蟹溞状Ⅰ期幼体(ZⅠ)在前期投喂后期饥饿的条件下,随着前期摄食时间的增加,幼体变态率和发育速度呈上升趋势,50%营养储存饱和点(PRS50)出现在47.5 h,100%营养储存饱和点(PRS100)出现在72 h;在前期饥饿后期投喂的条件下,随着前期饥饿时间的增加,幼体变态率和发育速度呈下降趋势,50%不可恢复点(PNR50)出现在39 h,100%不可恢复点(PNR100)出现在56 h.     

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不同盐度对克氏螯虾幼虾代谢率的影响

研究了不同盐度对克氏螯虾(Procambarus clarkii)幼虾耗氧率和排氨率的影响.试验用虾体长(3.13±0.30)cm,体重在(1.82±0.21)g.在25℃条件下,试验设置0、2、4、6、8、10、12共7个盐度梯度.在试验设置的盐度范围内,在盐度为2时,克氏原螯虾幼虾的的耗氧率与排氨率最低,由此可以表明幼虾对盐度调节的等渗点在2左右.随着盐度升高,幼虾的耗氧率和排氨率也随之上升,Turkey HSD test发现,在对照组、2、4和6盐度组的耗氧率、排氨率差异明显(P＜0.05).超过0～6的盐度范围时,盐度对幼虾的耗氧率、排氨率影响与对照组的差异显著(P＜0.05).     

太湖蓝藻水华遥感动态监测预警信息系统

太湖蓝藻水华暴发对其周边地区的生态、经济和社会造成了严重影响,对蓝藻水华进行监测预警对于改善太湖水环境具有重要意义。本文在分析蓝藻水华遥感监测预警研究动态基础上,从信息系统构建角度,结合太湖蓝藻水华监测情况,对太湖蓝藻水华遥感监测预警流程进行系统性分析,提出建立太湖蓝藻水华遥感监测预警系统的总体框架,利用C#语言和IDL语言实现了该框架的软件架构,并且论述了实现该系统框架所采用的系统集成技术和软件模式技术。     

第二次全国农业用地普查表的面积生成差异机制分析

第二次全国农业普查户表、村表与农业用地表的耕地面积差异,主要是由设计普查指标、普查时点、统计口径、登录技术等因素所致。另外,村与村之间界线不清,普查员对三权(所有权、使用权、承包经营权)理解模糊,对农户承包口粮田、种粮大户、户之间土地流转等混淆,以及土地全部征收、土地部分征收、土地未征收、"预征土地"等导致耕地面积的差异。由于城市不断向四周拓展,占用了大量的耕地,土地整理、易地待保、占补平衡进入实质性操作,人们的生存环境受到影响,对耕地面积的差异评估,产生诸多值得深思的问题。