Dynamic changes of habitats in China’s typical national nature reserves on spatial and temporal scales

Until 2015, China had established 2740 nature reserves with a total area of 1.47 million km², covering 14.8% of China’s terrestrial land surface. Based on remote sensing inversion, ecological model simulation and spatial analysis methods, we analyzed the spatial and temporal variations of fractional vegetation coverage (FVC), net primary production (NPP), and human disturbance (HD) in habitats of typical national nature reserves (NNRs) during the first 15 years of the 21st century from 2000 to 2015. And then the three indicators were compared between different NNR types and varied climate zones. The results showed that (1) the average 5-year FVC of NNRs increased from 36.3% to 37.1%, and it improved in all types of NNRs to some extent. The annual average FVC increased by 0.11%, 0.84%, 0.21%, 0.09%, 0.11% and 0.08% in NNRs of forest ecosystem, plain meadow, inland wetland, desert ecosystem, wild animal and wild plant, respectively. (2) The NPP annually increased by 2.06 g·m^-2, 1.23 g·m^-2, 0.28 g·m^-2 and 0.4 g·m^-2 in NNRs of plain meadow, inland wetland, desert ecosystem and wild animal, respectively. However, it decreased by 3.45 g·m^-2 and 2.35 g·m^-2 in NNRs of forest ecosystem and wild plant respectively. (3) In the past 15 years, besides the slight decreases in the NNRs located at the Qinghai-Tibet Plateau and the south subtropical zone, HD enhanced in most of NNRs, especially HD in the warm temperate humid zone increased from 4.7% to 5.35%.     

Fractional crystallization processes of magma beneath the Carlsberg Ridge(57°–65°E)

Fractional crystallization of basaltic magma at variable depths in?uences strongly the geochemical compositions of mid-ocean ridge basalts(MORBs), especially at slow-spreading mid-ocean ridges. The Carlsberg Ridge is a typical slow-spreading ridge located in the northwestern Indian Ocean. In this study, we conducted petrological, geochemical and modelling studies of MORBs collected along the Carlsberg Ridge from 57°–65°E to understand the fractional crystallization processes of magma and the controls on variations in MORB geochemistry. Our results show that the mantle sources beneath the Carlsberg Ridge are heterogeneous even on the local scale of a segment; such heterogeneity may be ubiquitous beneath the Carlsberg Ridge. Mantle heterogeneity may be caused by the enriched components resulting in the "DUPAL" anomaly, whereas the ef fect of pyroxenite on mantle heterogeneity is negligible. The parental melts experienced crystallization of olivine, plagioclase and clinopyroxene prior to eruption, which played a signi?cant role in the major and trace element variations in MORBs from the Carlsberg Ridge. The liquid lines of descent(LLDs), deduced from the forward modelling of three parental magma compositions using the Petrolog3 program at pressures between 1 atm and 10 kbar, demonstrate that clinopyroxene joined the olivine and plagioclase cotectic. The over-enrichment in highly incompatible elements relative to LLDs may be caused by the processes of replenishment-tapping-crystallization in magma chambers. The calculated crystallization pressures suggest that parental magmas beneath the Carlsberg Ridge experienced moderateto high-pressure crystallization and that crystallization beneath the slow-spreading Carlsberg Ridge may start at upper mantle depths.     

Occurrence and light response of residual plastid genes in a Euglena gracilis bleached mutant strain OflB2

Journal of Oceanology and Limnology - Euglena gracilis is a unicellular green eukaryotic microalga that features characteristics of both plants and animals. The photosynthetic function of its...     

内蒙古突泉县莲花山银铜矿床成矿地质背景探讨

文章通过对莲花山银铜矿床与成矿关系较密切的次火山岩的岩石化学、微量元素、稀土元素和同位素分析,对该矿床的成矿地质背景进行了探讨;认为莲花山银铜矿床是在太平洋板块向亚洲大陆板块俯冲下产生的弧后引张区,由来源于上地幔或下地壳的深源钙碱性岩浆多次上侵,在相对封闭的还原环境下形成的中高温热液矿床.     

Land cover classification of the North China Plain using MODIS_EVI time series

Moderate Resolution Imaging Spectroradiometer (MODIS) data have played an important role in global environmental and resource research. However, its low spatial resolution has been an impediment to researchers pursuing more accurate classification results. In this research, the high temporal resolution of MODIS was employed to improve the accuracy of land cover classification of the North China Plain using MODIS_EVI time series from 2003. Harmonic Analysis of Time Series (HANTS) was performed on the MODIS_EVI image time series to reduce cloud and other noise effects. The improved MODIS_EVI time series was then classified into 100 clusters by the Iterative Self-Organizing Data Analysis Technique (ISODATA). To distinguish ambiguous land cover classes, a decision tree was built on five phenological features derived from EVI profiles, Land Surface Temperature (LST) and topographic slope. The overall accuracy of the final land cover map was 75.5%, indicating the promise of using MODIS EVI time series and decision trees for broad area land cover classification.     

太阳轨迹空间连续性的日照分析算法优化

针对日照分析模拟必须考虑众多真三维地形/地物的遮挡因素,传统的日照分析方法难以在现实世界的复杂地理场景中得出高效、准确分析结果的问题展开研究,基于太阳运行轨迹的空间连续性,利用数据缓存方法对遮挡图元进行预判,实现了日照分析算法的优化。应用实例表明,将该方法与空间划分方法配合使用,可以在保证运算结果正确的基础上,进一步提高日照分析的计算效率,从而实现复杂地理场景中准确、快速的日照分析计算。     

Spatial-temporal characteristics of the “cumulative effect” of torrential rain over South China

To expand torrential rain, which is a meso- and microscale weather process, to a meso- and long-scale weather process, in this paper, we choose South China as a sample region and propose the conception of the “Cumulative Effect” of torrential rain (CETR) by using daily precipitation observational data from 740 stations. Through a statistical analysis of the observations, three indexes—continuous time (L _d), control area (A _r), and precipitation contribution rate (Q _s)—are used to define the CETR and indicate the torrential rain processes. The relationships between the CETR and simultaneous total precipitation over South China are analyzed in the pre-flooding and latter flooding seasons. This analysis shows that on both interannual and interdecadal scales, the three indexes are highly correlated with simultaneous total precipitation over South China in the pre-flooding season and latter flooding season. Moreover, an empirical orthogonal function (EOF) analysis is performed to classify the spatial distribution of the CETR. In both the pre-flooding season and the latter flooding season, the four major spatial models of torrential rain are similar to those of total precipitation over South China. With regard to the amount of precipitation caused by the CETR, the latter flooding season is affected more significantly than the pre-flooding season. Regarding the geographical distribution of precipitation, the opposite result occurs. In conclusion, in both the pre-flooding season and the latter flooding season, the CETR influences and even determines the amount and distribution of precipitation over South China.

     

Mg2B2O5晶须增强AZ91D镁基复合材料在Cl-溶液中腐蚀行为*

用电化学方法测量了Mg_2B_2O_5晶须增强AZ91D镁基复合材料在3.5%NaCl溶液中的开路电位、动电位极化曲线和交流阻抗,研究了晶须体积分数对镁合金基体耐腐蚀性能的影响,并利用SEM和XRD表征了腐蚀后复合材料表面的微观形貌和相组成。结果表明,随着Mg_2B_2O_5晶须体积分数的增加,AZ91D镁基复合材料的耐腐蚀性逐渐提高。当硼酸镁晶须的体积分数为35%时,材料的自腐蚀电位提高0.2V以上,自腐蚀流密度降低了1个数量级;SEM测试表明,复合材料表面生成了一层晶须增韧的腐蚀钝化膜,对基体起到保护作用。     

MICAPS系统的二次开发与应用

立足于预报业务技术体制改革和本地预报业务服务工作实际需要 ,对MICAPS系统进行综合性二次开发 ,使MICAPS系统发挥更大功效 ;为预报员提供更加方便、快捷和具有本地特色的人机交互工作平台     

机载三维成像仪航带拼接的误差处理研究

机载三维成像仪是集成了全球定位系统（GPS）、姿态测量装置、激光测距仪昨光谱成像仪的新一代航空遥感系统，它能直接得到的地学编码影像和数字地面模型（DTM），而无需地面控制点。利用图像上分布的具有三维坐标的激光点来纠正原始图像，并且生成DTM。该文首先分析了机载三维成像仪系统中各种传感器本身的误差和系统之间存在的误差，然后介绍了处理系统误差的方法－航带重叠区域灰度平均差值最小算法求解航带间的系统误差，同时还设计了一种变权方法来处理随机误差和拼接航带的地学编码图像。通过算例说明了处理算法的正确性。