丝绸之路经济带相似语言信息横向处理通信技术的研究

丝绸之路经济带为丝路沿线各国及地区带来的发展机遇。丝路沿线不同语言信息的交换及处理技术的提升将面临新的机遇与挑战。以蒙古文为实例,研究了丝路带相似多语言信息交叉处理通信问题,研讨了基于词典及语言学知识和基于统计的机器翻译（ SMT）两种方式的蒙文多语种文本的自动转写或翻译方法。试验结果显示,SMT方法对于相似语言转写的效果相比于语言学以及不同语系不同语族语言的翻译效果近提升一倍。     

青藏高原中西部湖泊生物标志物记录的过去两千年气候变化

以青藏高原中西部湖泊达则错和阿翁错为研究对象,通过分析湖泊沉积物岩芯中GDGTs、长链不饱和烯酮与叶蜡化合物单体氢同位素等生物分子标志物获得过去2000 a以来青藏高原中西部定量的温度与降水同位素记录,以期探讨晚全新世以来不同时段青藏高原气候变化区域特征,并揭示过去2000 a季风与西风对青藏高原影响范围的变化.结果表明:(1)青藏高原气候变化存在强烈的区域性特征,两个湖泊均存在中世纪暖期(MWP),但是暖期持续的时间有所不同,高原西部(阿翁错) MWP持续时间明显长于高原中部(达则错);达则错有明显的小冰期(LIA)降温,阿翁错没有发现明显的LIA,可能受样品分辨率低的影响;过去200 a达则错温度有缓慢降低趋势,可能是冰融水补给湖泊温度变化滞后于气候变化的表现.(2)过去2000 a印度夏季风在青藏高原的最北界线可能发生了北移,在距今1000～2000 a,夏季风边界线位于阿翁错以北、达则错以南;但在过去1000 a印度季风边界线移动到阿翁错和达则错以北.     

2000～2018年黄土高原沙尘天气遥感监测及尘源分析

利用19年（2000~2018）MODIS L1B数据对黄土高原102次沙尘天气过程进行遥感监测与分析,以探究黄土高原沙尘天气发生的时空规律。结果表明,黄土高原沙尘天气呈减少趋势,沙尘频发季节为春季。黄土高原沙尘源地主要分布在其西北部,位于沙地和沙漠区、农灌区与黄土丘陵沟壑区、黄土高原沟壑区等生态脆弱的原生沙尘暴带。黄土高原典型的沙尘源为活动沙丘及丘间沙地、干涸湖泊河道和农田等,表明沙尘天气频发是由自然因素和人为因素共同导致的。沙尘天气的遥感监测捕捉了黄土高原沙尘活动的时空变化特征,高效地识别了沙尘源地和尘源类型,对黄土高原气候变化、生态环境变化研究和环境修复与评价具有重要指导意义。     

末次冰盛期青藏高原冰川变化对亚洲气候的影响

以末次冰盛期(约2.6~1.9万年前)的气候为背景, 利用大气模式CAM4耦合陆面模式CLM4, 对青藏高原冰川规模扩大对气候产生的影响进行研究。结果表明, 末次冰盛期青藏高原冰川对北半球夏季的气候影响较显著, 除在冰川分布区引起显著的降温外, 通过遥相关作用, 还使得白令海峡附近显著升温。另外, 冰川产生的扰动会显著地增强南亚夏季风, 增加南亚地区降水。对比末次冰盛期与工业革命前时期不同气候态下青藏高原冰川规模扩大对气候的影响, 发现工业革命前时期的影响显著小于末次冰盛期, 说明青藏高原冰川对气候的影响与背景气候态有关。     

Changes in plant diversity on the Chinese Loess Plateau since the Last Glacial Maximum

Changes in biodiversity during periods of glo- bal warming are of broad public concern. To study the effect of the warming process on the ecosystem, we carried out pollen analyses on samples from seven selected sections at Qingyang, Ningxian, Yangling, Binxian, Baoji, Yanshi, and Lingbao on the Chinese Loess Plateau in order systematically to evaluate changes in plant diversity since the Last Glacial Maximum （LGM）. The plant richness indices （Simpson＇s diversity index and rarefaction analysis） indicated that the plant diversity of each section increased during the process of warming from the LGM to the Holocene Optimum, especially at Baoji and Lingbao. These results are consistent with many long-timescale geological records, which show that warming can increase biodiversity; therefore, the popular viewpoint that warming leads to biodiversity loss or species extinction needs to be re-examined.     

青藏高原太阳紫外线辐射及其生物学效应研究现状

青藏高原是世界上紫外辐射最强烈的地区之一,受臭氧层减薄及夏季臭氧低谷效应的影响,使得该地区紫外辐射更加强烈,这引起了人们对该地区紫外辐射研究的关注。紫外辐射具有强烈的生物学效应,能够对人体、动物、植物、微生物造成普遍的影响甚至伤害。青藏高原强烈的紫外辐射为研究紫外辐射的生物学效应提供了天然实验场地及材料,为寻求生物抗紫外辐射的遗传响应、相关生理生化机制提供了可能。通过对这一地区生物群落和生态系统开展紫外辐射相关研究,有可能在强紫外辐射生态学研究上取得突破性进展。     

青藏高原东部及周边地区热红外背景场特征

背景场是卫星红外地震异常研究的基础。利用均值法构建红外背景场,并从季节、纬度和地形等方面分析了强震高发的青藏高原东部及其周边地区的卫星红外辐射背景场特征。结果显示,青藏高原东部及其周边地区红外背景场具有明显的季节年变化特征,但不同地区的年变化趋势不完全一样;红外背景场具有纬度特征,高纬度地区年变幅度大,低纬度地区年变幅度小;红外背景场还具有地形特征,地形起伏大的地方红外辐射波动幅度大,地形起伏小的地方红外辐射波动幅度小,红外辐射与海拔成负相关关系。这些分析结果有助于深入理解卫星红外背景场,对卫星红外地震监测应用具有一定的科学参考价值。     

A very strong summer monsoon event during 30–40 kaBP in the Qinghai-Xizang (Tibet) Plateau and its relation to precessional cycle

Guliya ice core records, high lake-level records in the Qinghai-Xizang Plateau and at its north side as well as vegetation succession records indicated that during the period of 30–40 kaBP, namely the later age of the megainterstadial of last glacial period, or the marine oxygen isotope stage 3, the climate of the Qinghai-Xizang Plateau was exceptionally warm and humid, the temperature was 2–4°C higher than today and the precipitation was 40% to over 100% higher than the current average, all these suggested the existence of an exceedingly strong summer monsoon event. It has been inferred that the occurrence of such an event was attributed, on the one hand, to the stronger summer low pressure over the Plateau, which strengthened the attraction to the summer monsoon; on the other hand, to the vigorous evaporation of the tropic ocean surface, which promoted the moisture-rich southwest monsoon to flow over the Qinghai-Xizang Plateau. The background responsible for the formation of the very strong summer monsoon was that the period of 30–40 kaBP was just in the strong insolation stage of the 20ka precessional cycle, when the Qinghai-Xizang Plateau received extraordinary strong solar radiation and thus enlarged the thermodynamical contrast between the Plateau and the midsouth part of the Indian Ocean.     

The effect of land use structure on the distribution of soil nutrients in the hilly area of the Loess Plateau, China

The irrational land use is one of the main reasons for the soil erosion and nutrienloss in the loess hilly area of China. In this project, 4 types of typical land use structure of sustain ment for about 15 years in the loess hill slope are selected to study the effect of land use structure on the distribution of soil nutrients. From hill bottom to hill top, the patterns of land use types are: grassland-slope farmland-forest, slope farmland-grassland-forest, terrace-grasslandforest and slope farmland-forest-grassland. By measuring the contents of the total N, total P, available N, available P and organic matter of soils, the results show that the land use structure types of slope farmland-grassland-forest and terrace-grassland-forest have a better capacity to maintain the soil nutrients.     

Tomographical evidence for Indian Plate underthrusting only beneath Tethyan Himalaya

Tomographical inversion was performed using the data recorded by 51 seismographys deployed on a profile that followed southern Xizang (Tibet) high-way through a Sino-French Joint seismic experiment. The results indicate that the underthrusting Indian Plate is limited to the south of Indus-Yarlung Zangbo Suture (IYS) beneath Tethyan Himalaya, extends vertically to 150 km deep with relatively high angle near Gala, and becomes horizontally northward. The seismic velocities beneath Kang-mar, Gangdise and Yangbajain-Golug rift in the middle of the lithosphere show low velocity features, which may indicate the existence of high temperature and partial melting. The results from tomography strongly suggest that the continent-continent subduction occurred only beneath Himalaya and was confined to the south of IYS since the collision between India and Eurasia.