Possible influence of Arctic oscillation on precipitation along the East Asian rain belt during boreal spring

Theoretical and Applied Climatology - The sandy land in the southern region of the Tengger Desert is adjacent to cities and towns, and land desertification poses a threat to the livelihood and...     

Sources of spread in simulations of Arctic sea ice loss over the twenty-first century

We show that intermodel variations in the anthropogenically-forced evolution of September sea ice extent (SSIE) in the Arctic stem mainly from two factors: the baseline climatological sea ice thickness (SIT) distribution, and the local climate feedback parameter. The roles of these two factors evolve over the course of the twenty-first century. The SIT distribution is the most important factor in current trends and those of coming decades, accounting for roughly half the intermodel variations in SSIE trends. Then, its role progressively decreases, so that around the middle of the twenty-first century the local climate feedback parameter becomes the dominant factor. Through this analysis, we identify the investments in improved simulation of Arctic climate necessary to reduce uncertainties both in projections of sea ice loss over the coming decades and in the ultimate fate of the ice pack.     

准噶尔盆地周缘造山带裂变径迹研究及其地质意义

通过对准噶尔盆地东西两侧造山带地质剖面观察、系统裂变径迹测年与热演化模拟结果分析,并结合前人研究结果,准噶尔盆地周缘造山带中,主要经历了中生代晚期构造热事件。通过裂变径迹分析对比,准噶尔盆地两侧造山带具有不同的隆升历史,盆地西北缘早于东部隆升,隆升速率亦大于东部。准噶尔盆地西北缘自白垩纪以来经历了由准噶尔盆地边缘向扎伊尔山先后依次隆升事件,表明了准噶尔西北缘逆冲断裂系向盆内后展式逆冲推覆。准噶尔盆地东西两侧造山带岩石裂变径迹数据均反映了白垩纪以来的冷却隆升事件,充分证实了燕山晚期构造运动在准噶尔地区的普遍存在,为详细研究燕山期新疆北部陆内构造活动提供了证据。     

我国二氧化碳排放的区域分析

利用我国能源统计数据,对我国及各省区的CO2排放总量、排放强度、人均排放量和排放密度进行了计算。通过分析发现我国CO2排放具有较为明显的东西部差异,总体表现为东部发达省区排放总量大、排放强度低、人均排放多、排放密度高的特点,而中西部尤其是西部地区则表现出相反的特征。在分析我国CO2排放区域特征的基础上,分析出现以上地域差异的主要原因,并针对区域减排行动可能存在的问题进行了探讨,提出以省区为单位,降低排放强度可以取得实际的、可跟踪的减排效果,但需要考虑到全国各省区在功能定位、减排成本、资源环境条件等方面的差别,以及建立基于技术与资金合作的联合减排机制的可行性和障碍等因素。     

A Review of the Scientific Assessment and Research on Household Carbon Emission

Household consumption represents an important proportion of all energy consumption,and it is an important source of CO₂ emission. But household consumption and carbon emissions are often overlooked in climate change policies and measures. Through literature review, the research status of household consumption and carbon emissions were reviewed. On this basis, the main aspects and directions of the research are summarized and the main research of household carbon emissions should focus on three aspects in the future: ①The impact of income, consumption levels and other factors on household carbon emission; ②The relationship between direct and indirect carbon emissions of household carbon emission; ③The structure and source of household carbon emission. In future research, there are four issues which need in-depth study: ①Index and models study of household carbon emissions;②Impact of demographic change on household carbon emissions; ③The path of how to achieve sustainable and green urban lifestyle;④The relevant policy research of household carbon emissions.     

An Review of International Climate Change Conference and Analysis on Recent Hot Issues

The international climate change negotiation has been carried out over 20 years. The issue of climate change has shifted from a scientific question into a complex political matter which is related to the sustainable development of mankind. Based on the overview of major processes and stages of international climate conferences, this paper analyzed the key measures that major countries have taken to address climate change, as well as the primary tasks of Paris climate conference and recent international actions. The recent international climate policy issues were also analyzed in order to provide suggestions for China’s activel participation in the development of a new round of international climate change system.     

图像重建块迭代算法中松弛参数选取的研究

在图像重建中,Landweber迭代算法是图像重建算法中的重要方法。本文将针对Landweber分块迭代算法中松弛参数的选取进行研究。在重建过程中采取对投影矩阵按投影角度分块的方法,选取特定的松弛参数。通过数值实验得出结论:对于按角度分块的块迭代算法,松弛参数选取为λ乘以块矩阵与其共轭转置矩阵乘积的最大特征值分之一,当采集完全投影数据,且λ接近(1/6)~(1/7)时效果最好。另外,本文按角度分块的做法和松弛参数的选取方法对于有限角度图像重建问题也是可行的。     

中国大陆中强以上地震余震分布尺度的统计特征

依据1970年以来记录相对完备的MSge;5.0地震序列资料，统计研究了中国大陆余震分布尺度与序列最大地震震级M0及最大地震破裂形式之间的关系. 在95%置信概率下，考虑主震破裂形式， 分序列类型给出了余震分布尺度与M0之间的统计关系. 定性而言，余震分布尺度的对数lgR与M0正相关， 但数据分布较为离散. 分类型来看， 孤立型序列余震分布尺度与M0之间统计相关程度低， 余震分布尺度介于5~60 km之间； 主余型序列lgR与M0正相关； 多震型序列当M0le;6.2时lgR与M0之间相关性不显著，余震分布尺度介于5~70 km之间， 当M0ge;6.3时lgR与M0线性相关. 统计结果还表明， 走滑近走滑及斜滑型主震所导致序列类型比例之间没有显著差异，而倾滑近倾滑型主震（主要为逆断型破裂）所导致的主余型序列所占比例较高， 孤立型及多震型序列所占比例则相对较低. 对比研究显示， 当M0较高时，余震分布尺度主要取决于主震大小而与主震破裂形式关系不明显.      

新疆7级强震前的围空特征

讨论了新疆40年代以来所发生的8次7级强震前的围空现象。结果表明,除1974年巴里坤7.1级地震因资料不全外,7级强震前均出现明显的围空现象。研究发现,这种围空一般都经历了三个过程,时间通常为10—20年。最后分析讨论了7级强震前围空的特征以及判别指标。这将为今后确定强震危险区提供依据。     

Experimental study of surface texture and resonance mechanism of booming sand

The sound-producing mechanism of booming sand has long been a pending problem in the blown sand physics. Based on the earlier researches, the authors collected some silent sand samples from Teng- ger Desert, Australian Desert, Kuwait Desert, beaches of Hainan Island and Japanese coast as well as the soundless booming sand samples from the Mingsha Mountain in Dunhuang to make washing ex- periments. In the meantime the chemical corrosion experiment of glass micro-spheres, surface coating experiment and SEM examination were also conducted. The experimental results show that the sound production of booming sand seems to have nothing to do with the presence of SiO2 gel on the surface of sand grains and unrelated to the surface chemical composition of sand grains but is related to the resonance cavities formed by porous (pit-like) physical structure resulting from a number of factors such as wind erosion, water erosion, chemical corrosion and SiO2 gel deposition, etc. Its resonance mechanism is similar to that of Hemholz resonance cavity. Under the action of external forces, nu- merous spherical and sand grains with smooth surface and porous surface are set in motion and rub with each other to produce extremely weak vibration sound and then become audible sound by human ears through the magnification of surface cavity resonance. However the booming sands may lose their resonance mechanism and become silent sand due to the damping action caused by the invasion of finer particles such as dust and clay into surface holes of sand grains. Therefore, clearing away fine pollutants on the quartz grain surface is an effective way to make silent sand emit audible sound.