Ecosystem Carbon Allocation of a Temperate Mixed Forest and a Subtropical Evergreen Forest in China

Ecosystem carbon allocation can indicate ecosystem carbon cycling visually through its quantification within different carbon pools and carbon exchange. Using the ecological inventory and eddy covariance measurement applied to both a mature temperate mixed forest in Changbai Mountain (CBM) and a mature subtropical evergreen forest in Dinghu Mountain (DHM), we partitioned the ecosystem carbon pool and carbon exchange into different components, determined the allocation and analyzed relationships within those components. Generally, the total carbon stock of CBM was slightly higher than that of DHM due to a higher carbon stock in the arbor layer at CBM. It was interesting that the proportions of carbon stock in vegetation, soil and litter were similar for the two mature forests. The ratio of vegetation carbon pool to soil carbon stock was 1.5 at CBM and 1.3 at DHM. However, more carbon was allocated to the trunk and root from the vegetation carbon pool at CBM, while more carbon was allocated to foliage and branches at DHM. Moreover, 77% of soil carbon storage was limited to the surface soil layer (0-20 cm), while there was still plentiful carbon stored in the deeper soil layers at DHM. The root/shoot ratios were 0.30 and 0.25 for CBM and DHM, respectively. The rates of net ecosystem productivity (NPP) to gross ecosystem productivity (GPP) were 0.76 and 0.58, and the ratios of ecosystem respiration (Re) to GPP were 0.98 and 0.87 for CBM and DHM, respectively. The net ecosystem carbon exchange/productivity (NEP) was 0.24 t C ha^-1 yr^-1 for CBM and 3.38 t C ha^-1 yr^-1 for DHM. Due to the common seasonal and inter-annual variations of ecosystem carbon exchange resulting from the influence of environmental factors, it was necessary to use the long record dataset to evaluate the ecosystem sink capacity.     

Relationships between Genetic Diversity of Vascular Plant Species and Climate Factors

Genetic diversity is crucial for plants to respond to global climate change, and exploring relationships between genetic diversity and climatic factors may help predict how global climate change will shape the genetic diversity of plants in the future. So far, however, the extent and magnitude of the impact of climatic factors on the genetic diversity of plants has not been clarified. We collected data from 68 published papers on two widely used measures of genetic diversity of populations (average expected heterozygosity (He) and average observed heterozygosity (Ho)) and on localities of populations of 79 vascular plants, and extracted data on 19 climatic factors from WorldClim. We then explored the relationships between measures of genetic diversity and climatic factors using linear regressions. He of plant populations was significantly correlated with climatic factors in 58.7% (44) of the 75 species that used He as a measure of genetic diversity, and Ho was correlated with climatic factors in 65.1% (41) of the 63 species that used this genetic diversity measure. In general, Mean Temperature of Wettest Quarter, Precipitation Seasonality, Precipitation of Driest Quarter and Temperature Seasonality played a vital role in shaping He, and Ho was mostly correlated with Precipitation of Warmest Quarter, Mean Temperature of Wettest Quarter, Precipitation of Driest Quarter and Precipitation of Driest Month. Also, the proportion of the significant correlations between genetic diversity of populations and climatic factors was higher for woody than for herbaceous species, and different climatic factors played different roles in shaping genetic diversity of these two growth forms. Our results suggest that climate may play an important role in shaping genetic diversity of plant populations, that climatic change in the future may alter genetic diversity of plants, and that genetic diversity of different plant forms may respond to climatic change differently.     

天津地面相对湿度资料的非均一性检验及订正

研究中利用NCEP/DOEAMIP-ⅡReanalysis(R-2)比湿再分析资料和基础观测资料两种参考序列,对天津历史月平均相对湿度数据中存在的非均一性因素进行了检验和订正。结果显示,有9个地面站的相对湿度序列存在显著断点,占台站总数的69%。查阅台站元数据得到导致其突变的主要原因是自动站业务化,其次为迁站和仪器变更。从订正量来看,负订正量比例约占96. 3%,其中分布范围在-5.0%～-1.5%,约占总订正量的80%以上。对比分析订正前后月平均相对湿度序列的方差和趋势变化,均一性订正基本修正了非均一性因素造成的突变影响,减缓相对湿度序列长期出现异常偏干的趋势变化。同时,与朱亚妮等(2015)研制的同类数据产品误差分析发现,两类数据的误差平均值较小,但由于一些主观因素影响使得个别台站MAE、SE误差值达到3. 0%以上,造成MAE、SE误差值范围在0～2%的台站比例分别仅在84. 6%和76. 9%及两者以上。从而,一定程度上能够反映出本研究所采用的数据处理技术手段相对以往具有优越性。     

北印度洋-南海季风区热带海洋极端波候变化特征

利用1979—2016年ERA-Interim有效波高（SWH）和海表风场数据,分析了南海-北印度洋极端海浪场分布和变化.结果表明：南海-北印度洋极端SWH分布和极端风速分布形态以及年际变化趋势高度一致,说明了涌浪为主的北印度洋和风浪为主的南海一样,极端SWH都由局地的极端风速控制;强极端SWH主要分布在阿拉伯海以及南海北部,阿拉伯海北部增长与该区域气旋强度增强有着密切关系,而南海的极端SWH主要受东北季风控制;东非沿岸极端SWH线性增长趋势则与索马里急流的年代际尺度上有逐渐增强的线性趋势有关.北印度洋及南海海域极端SWH距平场的EOF分析结果表明,南海极端SWH与北印度洋表现出反相变化的特征.北印度洋（南海海域）极端SWH多出现在西南季风（东北季风）期间,因为在西南季风（东北季风）期间,极端风速也相对增强.     

京津冀地区人口与经济协调发展关系研究

京津冀地区是中国重要的人口集聚区和经济增长极,在京津冀协同发展的背景下研究京津冀地区人口与经济的协调发展关系,对于促进区域内经济的可持续发展具有重要意义。本文基于京津冀地区2000-2010年各区(县)和2000-2014年各城市的人口、GDP数据,运用人口—经济增长弹性、地理集中度、不一致指数、重心分析等方法探究京津冀地区人口与经济的协调发展关系,结果表明：①在总量规模上,京津冀地区整体人口增长与经济增长的协调度较高,但各城市人口增长与经济增长的协调度存在较大差异。②在空间分布上,从地理集中度来看,京津冀地区人口、经济地理集中度均呈现北部低、中南部高的分布特征,其中北京、天津经济地理集中度高于人口地理集中度,河北多数城市人口地理集中度高于经济地理集中度;从重心来看,京津冀地区整体的人口与经济重心都向东北方向移动,且经济重心的移动幅度大于人口重心,2个重心偏离距离不断加大,此外各城市的人口重心与经济重心也出现不同程度的分离。最后,提出了促进京津冀地区人口与经济协调发展的政策建议。     

DEM空间插值方法对土壤侵蚀模拟的影响研究——以USPED分析干热河谷典型冲沟为例

为探索不同空间插值方法得到的DEM如何影响土壤侵蚀模拟效果,本文选择金沙江干热河谷区典型冲沟为研究对象,利用野外测量高程数据,采用反距离加权(IDW)、析取克里格(DK)、局部多项式(LPI)和张力样条函数(ST)4种方法构建高精度DEM。基于USPED模型模拟冲沟的土壤侵蚀,对比不同空间插值方法的精度、土壤侵蚀的空间分布,采用相对差系数对比不同插值在土壤侵蚀研究中的相似性。结果表明：DEM空间插值的精度排序为ST相似文献   

电子地图与地理信息的公共服务

地图是一种描述地理实体的符号化图像和一种传输地理信息的工具。电子地图是传统地图与计算机技术、GIS技术、网络技术相融合的产物,是地理信息的符号化表现,是空间信息与专题信息的结合,是传统测绘产业技术改造的结果,是提供地理信息公共服务的重要渠道,突破了传统纸质地图时间和空间上的局限性,具有更丰富的信息含量和更广阔的应用范围。文中以加拿大为例,介绍电子地图在Web环境和Mobile环境下的应用情况,前者包括城市电子地图、全球地图搜索引擎和三维地球资源探索,后者包括数据采集服务、位置服务和导航定位服务。     

矢量地图图幅裁剪技术研究

针对矢量地图的图幅裁剪要求,讨论了目前矢量地图图幅裁剪的原理和方法,并提出一种图幅裁剪的通用算法,适应于对矢量数据中的点、线和面数据的裁剪。实验表明,该算法运行快速,可靠性高。     

车辆监控的信息管理系统设计及其关键技术分析

本文针对大量车辆的位置定位及其信息管理等主要内容进行了研究,给出了具有广泛扩展性的车辆监控管理信息系统的设计,并对其关键技术进行了探讨,最后给出了基于GPS与GPRS的系统实例测试分析。     

基于GF模型的BDS-3/GPS/Galileo三频模糊度固定性能分析

基于实测数据评估基于无几何（geometry-free,GF）模型的BDS-3/GPS/Galileo三频模糊度固定性能。首先给出适用于BDS-3/GPS/Galileo短基线TCAR（triple-frequency carrier ambiguity resolution）算法的三频线性组合;然后基于不同长度的实测短基线数据,评估BDS-3/GPS/Galileo超宽巷、宽巷及窄巷模糊度单历元固定性能。结果表明,对于5 m、3.6 km和13.1 km三条基线,BDS-3/GPS/Galileo超宽巷模糊度固定率相当（99.7%以上）,BDS-3/GPS宽巷模糊度固定率（97.2%以上）略优于Galileo（93.0%以上）,BDS-3窄巷模糊度固定率（92.2%以上）略优于GPS/Galileo（89.4%以上）。