我国西北干燥区地面气象站观测环境代表性思考

气候观测环境代表性和观测资料质量是开展大尺度气候变化监测和研究的前提。为了解我国干燥区气象观测环境变化和台站代表性,作者对河西走廊和北疆九个国家级气象站观测环境开展了调研。本文介绍了调研了解到的情况,并结合先前研究结果,从气候变化监测和研究的视角,讨论了西北干燥区地面观测站代表性问题。目前我国西北地区气象站地面观测,对于干燥区的城市和绿洲区域气候及其变化,具有较高的代表性,但对更广大的荒漠和半荒漠背景气候及其变化,代表性仍显不足。作者发现,早先研究中指出的北疆等地区城镇站地面气温序列负向城市化影响,应与观测场周围局地甚至区域尺度绿洲扩大有直接联系,较难反映绿洲以外干燥区地带性气温变化。针对地面观测环境调研所发现的问题,文章最后提出了几点建议,希望对未来国家基准气候站网设计和建设提供一定参考。     

Inversion of two-dimensional tidal open boundary conditions of M<Subscript>2</Subscript> constituent in the Bohai and Yellow Seas

Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in which several IPs on the open boundary is assumed,values at these IPs can be optimized with an adjoint method,and those at other grid points are determined by linearly interpolating the values at IPs.The reasonability and feasibility of the model are tested by ideal twin experiments.In the practical experiment(PE) after assimilation,the cost function may reach 1% or less of its initial value.Mean absolute errors in amplitude and phase can be less than 5 cm and 5°,respectively,and the obtained co-chart can show the character of the M2 constituent in the BYS.The results of the PE indicate that using only two IPs on the open boundary can yield better simulated results.     

南堡凹陷南部沙一段控砂模式

南堡凹陷盆地内部构造特征复杂,砂体时空分布差异较大。为了明确砂体分布规律,首先对南部缓坡带构造-沉积背景进行研究和岩心相观察,识别了沙一段辫状河三角洲前缘砂体;进而通过对南部缓坡带层序地层格架的建立、沉积学研究和地震地质解释,发现沙一段砂体同时受到顺源和逆源两种同沉积断裂坡折带类型控制。其中,顺源坡折带控制了断槽物源通道的走向,逆源坡折带改变了水流的流向,阻止了砂体的运移。据此,建立了南堡凹陷南部缓坡带沙一段同沉积断裂的控砂模式,得出沙一段砂体具有"沙垒田凸起供砂,断槽物源通道输砂,逆源坡折带阻砂和同沉积洼槽带聚砂"的发育特点。     

海水中溶解态铵盐氮同位素分析的预处理方法

以蒸馏法为基础, 研究了适合海水中铵盐稳定氮同位素分析的预处理方法。对蒸馏法预处理过程中的最佳蒸馏时间、沸石的选取、铵盐最适浓度范围等分别进行改进和优化, 获得稳定、高效的海水中铵盐氮稳定同位素分析预处理方法。结果表明: 最佳蒸馏时间为50 min, 铵盐的回收率为(97±5.8)%。测定了不同沸石对不同浓度氨氮的吸附率, 筛选出酸性条件下铵氮吸附效率较高且稳定的康华科技沸石; 确定铵盐的最佳适用浓度范围为2～10 μmol/L, 在该浓度范围内氮回收率94%～99%,氮分馏系数为0.1‰～0.8‰。将此方法应用于长江口海域水样分析, 结果表明, 这一方法可以应用于河口中铵盐的氮同位素分析, 能够为河口中溶解态氮的来源及循环机理等研究提供有效信息。     

惠民县土地利用总体规划实施中存在的问题及规划修编建议

惠民县上一轮规划是根据《中华人民共和国土地管理法》和中共中央国务院《关于加强土地管理切实保护耕地》的要求,在县政府统一领导下,于1997年12月至1998年10月完成的县、乡（镇）两级土地利用总体规划的编制任务。规划是以1996年为基期,以2000年为近期目标年,2010年为规划目标年。该规划以控制建设用地保护耕地为重点,以耕地保有量和基本农田面积不低于上级下达的控制指标,建设占用耕地和城镇规模不突破上级控制指标,补充耕地面积不少于上级下达的控制指标为总原则,规划指标落实方法是在专题研究的基础上,实行逐级控制,上级控制下级,层层分解落实。     

Changing spatial and structural patterns of non-agricultural activities in outward-moving Beijing urban fringe

As responses to metropolitan suburbanization and rural urbanization,the formation and evolution of urban fringes should be understood against the background of overall economic development and spatial reconstruction of entire metropolises.At the same time,however,endogenous interactions between industrial structure and spatial patterns of non-agricultural activities are also worthy of scholarly attention.Since the 1980s,studies on urban fringes in China have been restricted by the lack of micro-level data.This paper investigates the spatial expansion and structural evolution of the urban fringe by taking the case of Beijing and uses systematic firm-level data in 1996 and 2001 from the National Census of Basic Units.The diversity of distribution patterns across industrial sectors brings about two interrelated results.On the one hand,structural adjustment of non-agricultural industries promotes the expansion and spatial evolution of the urban fringe.On the other hand,the stability and dynamics of industrial structure coexist in the moving urban fringe.This study also reveals that the outward-moving urban fringe is the optimal location for manufacturing,especially heavy manufacturing,as well as traditional producer and consumer services.However,industries with spatial stickiness such as tourism and sports have not moved with the fringe.Most advanced services remain concentrated in the city center.The authors argue that it is essential for understanding and managing urban fringes to take into account spatial evolution and industrial structural adjustment together with their interaction with each other.