Dynamic control on grain-size distribution of terrigenous sediments in the western South China Sea: Implication for East Asian monsoon evolution

High-resolution oxygen isotope stratigraphy of Core MD05-2901, which is located off eastern Vietnam in the western South China Sea （SCS）, was established and indicated that the core spans a time period of the past 450 ka. Based on the bulk density, fractional porosity and lithogenic content of the sediments, terrigenous mass accumulation rate （TMAR） was obtained, which is 4.9-6.0 g cm^-2 ka^-1 on average during interglacial stages, higher than that during glacial stages, i.e. 1.9-5.0 g cm^-2 ka^-1, which is different from northern and southern SCS which show higher TMAR in glacial stages. By principle component analysis of grain size distribution of all the samples, two main control factors （F1 and F2） were obtained, which are responsible for about 80% variance of granularity. The contents of grain size population 1.26-2.66 μm% and 10.8-14.3 μm% which are sensible to F1 show high-frequency fluctuation, and correlate well with the summer insolation at 15^o N. They exhibit a distinct cyclicity with frequencies near 23 ka and 13 ka, in contrast to a strong frequency peak near 100 ka obtained in proxies 4.24-7.42 μm% and 30.1-43.7 μm% controlled mainly by F2. The sedimentary character of this part of the SCS was controlled by variations of input flux from two main source areas, namely the southwest and north SCS, which were transported by different circulations of surface current forced by East Asian summer monsoon and winter monsoon respectively. We believe that the East Asian summer monsoon has fluctuated with high frequency and been forced by changes in solar insolation in low latitude associated with precession and half precession, while ice-volume forcing is probably a primary factor in determining the strength and timing of the East Asian winter monsoon but with less important insolation forcing.     

第27届男篮亚锦赛中国队与对手攻防能力对比分析

采用文献资料法、录像观察法、数理统计法、RSR 综合分析法等方法,对第27届亚洲男子篮球锦标赛的15支参赛球队的整体攻防实力进行 RSR 综合评价,对中国队与9支赛队及其中3强队（击败中国队的伊朗队、韩国队、中华台北队）的攻防能力进行比较分析。结果表明：伊朗队、韩国队、中国队攻防隶属 A 级水平球队;菲律宾队、中华台北队、卡塔尔队、约旦队属 B 级球队;哈萨克斯坦队、巴林队、日本队属于 C 级球队;印度队、沙特队、泰国队属 D级球队;中国香港队和马来西亚队攻防实力最弱,属 E 级球队;中国队攻防较为平衡,但攻略强于防。除罚球命中率外,中国队其它进攻指标均高于9支赛队,且两分球命中率与赛队存在显著性差异;中国队的投篮命中率低于3强队,且总投篮命中率、3分球命中率与3强队存在显著性差异;抢断、盖帽均低于对手,但犯规高于3强队。因此,中国队应提高高速度、强力量对抗中进攻的质量,注重外线队员远投训练,强化拼抢篮板球的意识和技术。     

The terraced thermal contrast among the Tibetan Plateau, the East Asian plain, and the western North Pacific and its impacts on the seasonal transition of East Asian climate

The heating sources over the Tibetan Plateau （TP）, the East Asian plain, and the western North Pacific （WNP） form a terraced thermal contrast in the west-east direction. Over East Asia and the WNP, this zonal thermal contrast contributes as high as 45 % to the seasonal variance based on the EOF analysis and exerts a significant impact on the seasonal transition of the East Asian climate through the enhancement of the year-round southerly to the southeast of the TP in late March and early April. This effect is investigated in this study using a high-resolution regional atmospheric model by doubling the surface sen- sible heat flux, respectively, over the TP, the East Asian plain, and the WNP in three sensitivity experiments. Comparisons among the experiments reveal that doubling the surface sensible heat flux over the WNP has little upstream response over East Asia. The increased zonal thermal contrast between the TP and the East Asian plain due to doubled heat flux over the TP would induce anomalous northerly over the region with year-round southerly to the southeast of the TP and weaken its seasonal enhancement. Doubling the surface sensible heat flux over the East Asian plain decreases the zonal thermal contrast and leads to southerly anomaly over the region with year-round southerly to the southeast of the TP and South China, which is favorable for the enhancement of the year-round southerly and its eastward extension.     

两头家:华南侨乡的一种家庭策略——以海南南来村为例

通过文献回顾,介绍"两头家"形成的社会背景、历史发展和特征。在此基础上,以家庭策略的视角对海南南来村"两头家"个案的家庭史进行分析。认为"两头家"是早期华南侨乡移民在"文化传统"与"社会结构"的框架下一种集体选择的家庭策略。     

南滚河流域亚洲象生境质量现状评价

 以2002~2006年南滚河流域野生亚洲象的实际活动范围(3613.32 hm²)为研究区.采用3S技术、法瑞学派野外群落样地调查方法并结合主成分分析法(PCA)和因子评分赋值法,选取了9个影响亚洲象的主要生境因子进行综合分析并对亚洲象生境质量现状进行评价,将生境质量划分为5个等级.结果表明:①优等生境,良好生境,中等生境,劣等生境,未利用生境所占面积比例分别为32.14%,8.97%,16.88%,40.77%,1.24%;②生境因子综合作用中,各权重赋值分别为水源地距离0.1620,坡向0.1493,海拔0.1431,植被类型0.1414,硝塘距离0.1224,坡度0.1050,稀泥塘距离0.0692,居民点距离0.0656,规一化植被指数(NDVI)0.0420;③亚洲象对各因素的最佳选择分别为:水源地距离200~400 m、坡向南,海拔700~900 m,植被类型半常绿季雨林,硝塘距离0~1000 m,坡度8°~15°,稀泥塘距离2000~3000 m,居民点距离4000~5000 m,NDVI>0.5.     

Inverse correlation between ancient winter and summer monsoons in East Asia？

There is a scientific debate on the relationship between ancient winter and summer monsoons in East Asia. Some scholars think that East Asian winter and summer monsoons are anti-correlated, and others think not. For this reason, this study is motivated to assess their linkage from the paleoclimate simulation perspective, through analyzing the Last Glacial Maximum （LGM） and mid-Holocene （MH） climate simulated by CCSM3 model. Compared to the present climate, the Aleutian low is found to be deepened and the East Asian winter monsoon （EAWM） is stronger during the LGM winter. The Pacific high in summer is noticed to be weakened and the East Asian summer monsoon （EASM） is weaker at the LGM. During the MH, the Aleutian low and the Asian high in winter are intensified, and the Asian low and the Pacific high in summer are enhanced, indicating that the EAWM and EASM are both stronger than today. Therefore, the EAWM is not always negatively correlated to the EASM. Their relationship may be different at different geological stages. It can be obtained at least from the numerical simulation results that the EAWM and the EASM is negatively correlated during the cooling period, while positively correlated during the warming period.     

Asian-Pacific Oscillation index and variation of East Asian summer monsoon over the past millennium

To study the long-term variation of the East Asian summer monsoon （EASM）, the Asian-Pacific Oscillation index （IAPO）, representing a zonal thermal contrast between Asia and the North Pacific, is reconstructed over the past millennium. During the Little Ice Age （LIA）, the variability of the reconstructed IAPO is closely linked to dry-wet anomalies in eastern China on the centennial scale. This correlation pattern is consistent with the observation during the current period, which suggests that the reconstructed IAPO may generally represent the centennial-scale variation of the EASM and rainfall anomalies over eastern China during the LIA.     

虹式亚洲期权定价

研究了一种奇异路径依赖型期权——具有虹式特征的亚洲期权的定价问题.基于Black-Scholes模型的假设条件, 利用多维ITO引理和无套利原理,构建了基于两个资产支付红利的虹式亚洲期权多因素路径依赖型期权定价模型,并结合边界条件,导出虹式几何平均亚洲看涨期权的解析定价公式以及虹式几何平均亚洲期权看涨-看跌平价关系式,以此为控制变量模拟计算虹式算术平均亚洲期权,数值实验表明虹式几何平均控制变量法有效地提高了蒙特卡罗模拟虹式算术平均亚洲期权定价的精确度.     

亚式期权定价问题的交替方向迎风有限体积方法

考虑亚式期权定价问题的数值求解.对亚式期权定价问题给出了恰当的边界条件,并提出了一类加权迎风有限体积格式和相应的交替方向格式.对价格漂移占优问题,采用加权迎风技术以避免数值解的非物理震荡;同时,结合亚式期权定价问题特性提出了相应的交替方向格式.从理论上严格证明了提出的格式满足极大值原理,得到了一致误差估计.     

The East Asian summer monsoon circulation anomaly index and its interannual variations

Based on the concept of East Asia-Pacific (EAP) teleconnection which influences East Asian summer monsoon, an index for East Asian summer monsoon circulation anomaly was defined and it was pointed out that this index can describle the interannual variation character of summer climate in East Asia, especially in the Yangtze River and Huaihe River Valley.