国际政治经济学视角下的“冰上丝绸之路”倡议

作为"一带一路"倡议与北极开发对接的合作设想,"冰上丝绸之路"建设不仅有助于北极地区经济社会的发展,促进全球交通贸易格局的均衡,还有助于缓解全球资源需求与供给的矛盾,促进可持续发展,更可以扩大和深化中国对外发展合作,塑造有利的发展环境。从历史经验来看,"冰上丝绸之路"的顺利推进必须以政治共识为前提,以经济效益为可持续的保障。鉴于北极地区特殊的地理环境和复杂的政治环境,"冰上丝绸之路"建设面临敏感的政治挑战和较高的经济技术成本,需要广泛的国际共识和技术合作。     

Impacts of future climate change on agroclimatic resources in Northeast China

In this study, the spatial distribution and changing trends of agricultural heat and precipitation resources in Northeast China were analyzed to explore the impacts of future climate changes on agroclimatic resources in the region. This research is based on the output meteorological data from the regional climate model system for Northeast China from 2005 to 2099, under low and high radiative forcing scenarios RCP4.5 (low emission scenario) and RCP8.5 (high emission scenario) as proposed in IPCC AR5. Model outputs under the baseline scenario, and RCP4.5 and RCP8.5 scenarios were assimilated with observed data from 91 meteorological stations in Northeast China from 1961 to 2010 to perform the analyses. The results indicate that: (1) The spatial distribution of temperature decreases from south to north, and the temperature is projected to increase in all regions, especially under a high emission scenario. The average annual temperature under the baseline scenario is 7.70°C, and the average annual temperatures under RCP4.5 and RCP8.5 are 9.67°C and 10.66°C, respectively. Other agricultural heat resources change in accordance with temperature changes. Specifically, the first day with temperatures ≥10°C arrives 3 to 4 d earlier, the first frost date is delayed by 2 to 6 d, and the duration of the growing season is lengthened by 4 to 10 d, and the accumulated temperature increases by 400 to 700°C·d. Water resources exhibit slight but not significant increases. (2) While the historical temperature increase rate is 0.35°C/10a, the rate of future temperature increase is the highest under the RCP8.5 scenario at 0.48°C/10a, compared to 0.19°C/10a under the RCP4.5 scenario. In the later part of this century, the trend of temperature increase is significantly faster under the RCP8.5 scenario than under the RCP4.5 scenario, with faster increases in the northern region. Other agricultural heat resources exhibit similar trends as temperature, but with different specific spatial distributions. Precipitation in the growing season generally shows an increasing but insignificant trend in the future, with relatively large yearly fluctuations. Precipitation in the eastern region is projected to increase, while a decrease is expected in the western region. The future climate in Northeast China will change towards higher temperature and humidity. The heat resource will increase globally, however its disparity with the change in precipitation may negatively affect agricultural activities.     

浅析当代专题地图的现状及应用前景

专题地图是文化的产物,其应用面、产品形式、应用价值都是随着时代的发展而变化的,不同时期、不同领域受关注的程度差异很大。本文从当今专题地图的现状着手,从专题地图的特性、发展条件及发展趋势几个方面进行了论述,分析了其应用前景。     

Common‐shot Fresnel beam migration based on wave‐field approximation in effective vicinity under complex topographic conditions

Gaussian beam migration is a versatile imaging method for geologically complex land areas, which overcomes the limitation of Kirchhoff migration in imaging multiple arrivals and has no steep‐dip limits of one‐way wave‐equation migration. However, its imaging accuracy depends on the geometry of Gaussian beam that is determined by the initial parameter of dynamic ray tracing. As a result, its applications in exploration areas with strong variations in topography and near‐surface velocity are limited. Combined with the concept of Fresnel zone and the theory of wave‐field approximation in effective vicinity, we present a more robust common‐shot Fresnel beam imaging method for complex topographic land areas in this paper. Compared with the conventional Gaussian beam migration for irregular topography, our method improves the beam geometry by limiting its effective half‐width with Fresnel zone radius. Moreover, through a quadratic travel‐time correction and an amplitude correction that is based on the wave‐field approximation in effective vicinity, it gives an accurate method for plane‐wave decomposition at complex topography, which produces good imaging results in both shallow and deep zones. Trials of two typical models and its application in field data demonstrated the validity and robustness of our method.     

安徽省区域旅游经济发展的时空格局演变

分析了安徽省区域旅游发展模式,以各市2001-2013年的旅游总收入、入境旅游收入和国内旅游收入为基础数据,从时间变化和空间演变两个方面分析安徽省区域旅游经济差异。结果表明：① 安徽省区域旅游产业的发展经历了点状模式、放射状模式、双核联动发展模式演化阶段;② 安徽省旅游经济发展不均衡,不同地市间旅游经济发展水平差异很大,国际旅游空间差异更是大于国内旅游,安徽省区域旅游经济空间差异的“南强北弱”基本格局没有发生根本的改变;③ 安徽省各地市旅游经济发展具有明显的首位分布特征,特别是入境旅游呈现出典型的首位分布,其总收入、国内旅游首位度大致经历了先降后升的演变,入境旅游首位度基本上呈现下降趋势,首位城市主要在黄山市和合肥市之间展开竞争;④ 旅游产业要素从时间角度看,旅游景区、旅行社和星级饭店增长迅速,从空间角度来看,旅游景区主要集中在黄山、安庆、六安等地,旅行社和星级饭店主要集中在合肥、黄山等地;⑤ 影响安徽省区域旅游时空格局演变的主要因素有旅游资源禀赋、旅游政策、交通网络、旅游市场需求、区域产业发展战略调整及区域经济发展水平等。     

疏勒河径流量与绿洲面积、农业产值及生态效益的关系

基于1954-2010 年疏勒河干流出山径流量、2000-2010年流域内灌区水资源供应量、灌区农作物种植类型、农作物及林草地面积等资料,通过建立系统动力学模型,探讨了气候变化背景下疏勒河径流量对绿洲的影响。结果表明:绿洲受径流量变化影响显著,若出山径流量按1954-2010 年变化趋势增加,绿洲面积、农业产值、生态效益将有不同程度增加; 若出山径流量减小,绿洲面积、农业产值、生态效益亦相应减小。2020年出山径流量较2010年分别减少5%、10%、15%时,绿洲面积和农业产值相应减小4.5%、8.9%、13.4%。在径流量不变情况下,若普及常规节水,林、草地面积均增加16%以上; 若普及高效节水,林、草地面积均扩大54.7%; 若提高渠系利用率到0.70,林草地面积扩大5%以上,总产值增加5.4%; 若提高渠系利用率到0.75,林草地面积增加12%以上,总产值增加12.2%。     

GB-Radar与测量机器人数据融合方法研究

分析了Ground-based Radar (GB-Radar)与测量机器人变形监测技术的特点,以及两种监测技术数据融合所带来的优势。通过分析两种监测系统的关系,建立了这两种变形监测系统数据配准和数据融合的数学模型。通过设计实验,获取了GB-Radar与测量机器人对角反射器的变形监测数据。结果表明,对GB-Radar雷达视线向一维变形量与测量机器人三维变形量进行数据融合得到的监测点三维监测数据,最大监测误差明显降低,监测精度达到亚毫米级。     

2013年甘肃岷县—漳县交界Ms6.6地震序列双差定位研究

利用甘肃遥测台网2013年7月22日至9月22日的震相观测报告,对2013年7月22日07时45分甘肃省岷县漳县交界Ms 6.6地震的地震序列进行双差定位研究.结果表明,地震序列呈北西向分布,与临潭宕昌断裂的走向基本一致,地震分布长度约10 km.震源深度剖面显示断层面向西南倾斜,浅部倾角较陡,深部略缓,表现为“铲形”逆冲断层的特征.余震区存在一条向西南延伸的余震带,与发震断层相交成y字型,推测可能是逆冲推覆构造中常见的反冲断层.     

Structural modal parameter identification and damage diagnosis based on Hilbert-Huang transform

Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the damping ratio and damage.In this study,methods based on the Hilbert-Huang transform(HHT) are investigated for structural modal parameter identifi cation and damage diagnosis.First,mirror extension and prediction via a radial basis function(RBF) neural network are used to restrain the troublesome end-effect issue in empirical mode decomposition(EMD),which is a crucial part of HHT.Then,the approaches based on HHT combined with other techniques,such as the random decrement technique(RDT),natural excitation technique(NExT) and stochastic subspace identifi cation(SSI),are proposed to identify modal parameters of structures.Furthermore,a damage diagnosis method based on the HHT is also proposed.Time-varying instantaneous frequency and instantaneous energy are used to identify the damage evolution of the structure.The relative amplitude of the Hilbert marginal spectrum is used to identify the damage location of the structure.Finally,acceleration records at gauge points from shaking table testing of a 12-story reinforced concrete frame model are taken to validate the proposed approaches.The results show that the proposed approaches based on HHT for modal parameter identifi cation and damage diagnosis are reliable and practical.     

基于CALIPSO星载激光雷达的中国沙尘气溶胶观测

基于2006年6月至2012年5月无云条件下CALIPSO星载激光雷达观测资料,分析中国典型地区（塔克拉玛干沙漠、柴达木盆地、戈壁区和华北）沙尘气溶胶分布。结果表明：塔克拉玛干沙漠和戈壁区为沙尘天气发生频率高值区,且前者在各高度层的沙尘发生频率都大于后者。沙尘发生呈季节性分布。塔克拉玛干沙漠在春季沙尘发生频率最大,抬升最高可至10 km,冬季频率最小,高度最低,主要分布在3 km以下。戈壁区在春季沙尘发生频率、抬升高度最大,冬季抬升高度最低,但低层发生频率大于夏、秋两季。在塔克拉玛干沙漠,沙尘光学厚度春季最大约为0.44,冬季最小约为0.17,春,冬季消光系数峰值最大,可达0.25 km^-1,且随高度的递减率大于夏,秋季。在戈壁区和柴达木盆地,沙尘光学厚度春季最大、秋季最小。在华北,沙尘光学厚度春季最大、夏季最小,消光系数在2 km以上春季最大,这主要是由于春季远距离高空传输到华北的沙尘量最多。塔克拉玛干沙漠与柴达木盆地的退偏比为0.2~0.35,戈壁区为0.16~0.28,可能是由于塔克拉玛干沙漠的物质组成与柴达木盆地相同,而与戈壁区不同。华北因低层沙尘与其他气溶胶混合导致退偏振比廓线随高度递增。4个区域对流层上部退偏比全为0.2,表明高空气溶胶可能为来自相同源区的沙尘。