iGMAS全球电离层TEC格网产品精度分析

为了分析与评估国际GNSS监测评估系统(iGMAS)全球电离层TEC格网产品精度,该文基于iGMAS及IGS各电离层分析中心发布的全球电离层TEC格网产品,进行了精度比较分析,结果表明:iGMAS与IGS、CODE、JPL、ESOC、UPC等IGS电离层工作组发布的全球电离层TEC格网产品,在全球、不同纬度带和欧洲等不同区域均表现出较高的一致性和强相关性,互差为0~2.0 TECU;JPL分析中心GIM的内符合精度约为2.5 TECU,iGMAS、IGS、CODE、ESOC和UPC等分析中心GIM的内符合精度均小于1.5 TECU;在2~8 TECU的精度范围内,iGMAS全球电离层TEC格网产品的精度总体与IGS、CODE、JPL、ESOC、UPC等IGS电离层工作组的精度相当。     

The Project Siberian High in CMIP5 Models

The Siberian high(SH)experienced a decline from the 1970s to 1990s and a recovery in recent years.The evolution of the SH under global warming is unclear.In this study,41 Coupled Model Intercomparison Project Phase 5(CMIP5)climate models are evaluated in terms of their ability to simulate the temporal evolution of the SH in the 19th and 20th centuries and the spatial pattern of the SH during 1981–2005.The results show that 12models can capture the temporal evolution of the SH center intensity(SHCI)for 1872–2005.The linear correlation coefficient between the SHCI from the Twentieth Century Reanalysis and the simulated SHCI from the multi-model ensemble(MME)of the 12 models is 0.3 on annual and inter-annual scales(above the 99%confidence level).On decadal and multi-decadal time scales,the MME also captures the pronounced reduction(between 1981–2000and 1881–1900 period)and the recovery(during1991–2005)of the SH intensity.Finally,the future evolution of the SH is investigated using the MME of the 12models under the+4.5 and+8.5 W m-2 Representative Concentration Pathway(RCP)scenarios(RCP4.5 and RCP8.5).It is shown that the SHCI,similar to the SHCI in the 20th century,has no significant long-term trend in the 21st century under global warming(RCP8.5 scenario).At the end of 21st century(2081–2100),the SH shows stronger interannual variability than the SH at the end of20th century(1981–2000).The increased interannual variability likely favors the increased interannual variability in winter air temperature over midlatitude Eurasia at the end of 21st century.     

A brief introduction to BNU-HESM1.0 and its earth surface temperature simulations

Integrated assessment models and coupled earth system models both have their limitations in understanding the interactions between human activity and the physical earth system. In this paper,a new human–earth system model,BNUHESM1.0,constructed by combining the economic and climate damage components of the Dynamic Integrated Model of Climate Change and Economy to the BNU-ESM model,is introduced. The ability of BNU-HESM1.0 in simulating the global CO2 concentration and surface temperature is also evaluated. We find that,compared to observation,BNU-HESM1.0underestimates the global CO2 concentration and its rising trend during 1965–2005,due to the uncertainty in the economic components. However,the surface temperature simulated by BNU-HESM1.0 is much closer to observation,resulting from the overestimates of surface temperature by the original BNU-ESM model. The uncertainty of BNU-ESM falls within the range of present earth system uncertainty,so it is the economic and climate damage component of BNU-HESM1.0 that needs to be improved through further study. However,the main purpose of this paper is to introduce a new approach to investigate the complex relationship between human activity and the earth system. It is hoped that it will inspire further ideas that prove valuable in guiding human activities appropriate for a sustainable future climate.     

Quantitative assessment of the spatial distribution of 239+240Pu inventory derived from global fallout in soils from Asia and Europe

Journal of Geographical Sciences - Due to the atmospheric nuclear weapon tests carried out, terrestrial environments have been extensively contaminated by global fallout of plutonium (Pu)...     

全球变化下北方农牧交错地带区域适应能力评价模型研究

以可持续发展理论为指导,依据2006年全球变化人类行为计划（IHDP）第六届开放会议精神,参考前人有关生态环境评价框架和指标组合研究,建立了适合北方农牧交错地带特点的区域适应能力评价模型（PSR-RAD）,并对模型的构建思想、参数意义和评价指标的具体计算进行了探讨,以期为全球变化区域响应研究提供参考。针对北方农牧交错地带的实际情况,PSRRAD模型将第四纪地质地貌与现代生态环境研究整合,提出第四纪地质脆弱指数概念,在生态环境胁迫分析中,提出衡量农牧交错地带农牧业环境胁迫程度的地农牧业生产量指数的概念,使生态环境先天与后天胁迫因子、自然与人文因子得以客观体现,对生态环境脆弱性研究的时间和空间尺度均有所拓展。     

西大滩地区光合有效辐射的基本特征

利用青藏高原多年冻土北界西大滩地区2005年度的辐射及气象观测资料,分析探讨了该地区光合有效辐射(PAR)的基本特征.结果显示:PAR日变化与总辐射(Q)日变化趋势一致,表现为中午大,早晚小;晴天的日变化曲线呈单峰型,变化相对比较平滑,阴天的日变化曲线不稳定,晴天的PAR大于阴天日.PAR具有明显的季节变化特征,表现为春夏季大,秋季次之,冬季最小,最大值出现在5月,最小值出现在12月.光合有效辐射系数ηQ值阴天大,晴天小;ηQ的日变化是中午小,早晚大,年变化呈双峰型,在1.75~1.96 mol.MJ-1之间变化,年平均值为1.88 mol.MJ-1.最后,提出了适合本地区PAR的气候学计算方法.     

“组织-贸易”视角下全球能源治理网络的基本结构及其边界重构

全球能源治理是当前能源话语权塑造的重要形式,其本质是能源利益主体间围绕多元能源议题而构建的关系网络。在以往相关研究中,各能源组织的架构、功能、绩效以及所产生的复杂影响占据了主要内容,而对于全球能源治理的整体结构以及内部关系却未能有进一步探索。本研究认为,能源组织与实际贸易存在交互关系,将二者相结合来进一步呈现和解释全球能源治理架构是有必要的。基于此,本研究以2019年为时间节点,收集主要能源组织的属性数据与各国之间的石油和天然气贸易数据,将国家间在能源治理组织的常态化合作关系与实际发生的能源贸易关系作为分析基础;并利用社会网络分析方法构建全球能源治理网络,探析其基本结构以及出现的“边界重构”现象。研究发现：(1)能源组织网络与能源贸易网络存在显著的结构性差异,在两种网络对比中,美国与俄罗斯均占据主导地位。(2)中国已经成为能源贸易大国,但在全球能源组织合作中不具优势,与传统能源利益集团之间缺乏正式的治理合作。(3)全球能源治理体系呈现出典型的“核心-边缘”结构,主要被划分为欧盟以及亚太-北美“社区”,其中OECD（经济合作与发展组织）国家占据“核心”地位;而以单一能源输出为主导功能的出...     

二战后全球宗教多样性时空格局演变及收敛性研究

运用LISA时间路径、收敛检验等方法考察了二战后全球宗教多样性发展的空间分布特征、格局演变以及在此过程中的收敛性。研究发现：（1）二战后宗教多样性呈先快后慢的上升趋势,1945—2015年间多样性指数增幅达81.07%。宗教分类上则主要表现为基督教信仰者数量的持续下滑以及伊斯兰教信仰者数量的稳步上升。（2）LISA时间路径表明二战后全球宗教多样性具有较强的空间锁定效应,且其空间演化具有较强空间整合性。（3）二战后全球宗教多样性水平存在着显著的σ收敛与绝对β收敛,即全球、洲级层面上宗教多样性水平的内部差异都在逐步弥合,宗教多样性水平较高的地区对周边较低地区存在溢出效应。（4）二战后全球宗教多样性演化受土地覆盖类型、国力指数、民族数量、人均GDP、人口规模等因素共同作用而收敛于不同的稳态水平;从洲级层面上来看,各洲级单元收敛性对影响因素的敏感程度不同,体现了二战后全球宗教多样性演化显著的地域分异性。     

Modeling of spatial distributions of farmland density and its temporal change using geographically weighted regression model

This study used spatial autoregression（SAR） model and geographically weighted regression（GWR） model to model the spatial patterns of farmland density and its temporal change in Gucheng County,Hubei Province,China in 1999 and 2009,and discussed the difference between global and local spatial autocorrelations in terms of spatial heterogeneity and non-stationarity. Results showed that strong spatial positive correlations existed in the spatial distributions of farmland density,its temporal change and the driving factors,and the coefficients of spatial autocorrelations decreased as the spatial lag distance increased. SAR models revealed the global spatial relations between dependent and independent variables,while the GWR model showed the spatially varying fitting degree and local weighting coefficients of driving factors and farmland indices（i.e.,farmland density and temporal change）. The GWR model has smooth process when constructing the farmland spatial model. The coefficients of GWR model can show the accurate influence degrees of different driving factors on the farmland at different geographical locations. The performance indices of GWR model showed that GWR model produced more accurate simulation results than other models at different times,and the improvement precision of GWR model was obvious. The global and local farmland models used in this study showed different characteristics in the spatial distributions of farmland indices at different scales,which may provide the theoretical basis for farmland protection from the influence of different driving factors.     

ȫ���������ģ�;���Ӱ�����ط���

??2012??1???????????????????г??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????к?????????????????????????????????--??????????????????????????????