利用COST-G GRACE时变模型反演黄土高原陆地水储量变化

综合利用COST-G GRACE时变重力场模型、降水、气温、GLDAS模型中地表水、实测浅层地下水和NDVI等多源数据,分析2002-04~2016-12黄土高原陆地水储量的时空变化特征,并利用偏最小二乘回归方法定性分析黄土高原陆地水储量变化的驱动因素。结果表明：1)研究时段内黄土高原陆地水储量具有上升-下降-平缓下降的变化特征,山西省陆地水储量亏损趋势明显;2) 2004~2009年采煤用水、人类生活用水和植被作用是黄土高原陆地水储量下降的重要因素,2010~2016年工业用水、人类生活用水和气温上升是黄土高原陆地水储量下降的重要因素。     

Climate changes detected through the world's longest sea level series

The sea level series of Stockholm in the Baltic Sea, commencing already in 1774, is analysed in various ways together with contemporary climate data, in order to investigate long-term sea level changes and their relations to climate changes.First, a study of the eustatic rise of sea level, based on annual mean sea levels, is peformed, and compared with other sea level and climate studies. It is concluded that the general climatic rise of sea level has increased significantly (99.9%) from about 0.0 mm/year during the end of the Little Ice Age, to about 1.0 mm/year during the past century, characterized by melting of glaciers. Such sea level changes due to northern hemisphere climate variations since 800 A.D. have (hitherto) probably always kept within −1.5 and +1.5 mm/year, with an average fairly close to zero.Second, an investigation of the sea level variability, also based on annual mean sea levels, is performed together with temperature and wind variabilities. It is found that the interannual sea level variability of the Baltic Sea has decreased significantly (98%) from the end of the 1700s to the beginning of the 1900s; after that it has increased significantly (95%) again. Precisely the same is found to apply to winter climate or, more specifically, to the interannual winter temperature variability and the interannual winter wind variability. The common origin of all these long-term changes turn out to be two consecutive winter wind processes over the North and Baltic Seas, especially the Baltic entrance. From the end of the 1700s to the beginning of the 1900s, there has been a rapidly decreasing number of dominating winter winds from northeast, and after that there has been an increasing number of dominating winter winds from southwest. This may indicate corresponding long-term changes in the North Atlantic Oscillation.Third, using monthly mean sea levels together with corresponding wind data, seasonal variations are investigated. The seasonal sea level variation in the Baltic Sea has increased significantly (99%) since the early 1800s, together with a shift of the maximum from late summer to early winter. It is found that the main origin is a secular change of the winter wind conditions over the Baltic entrance, with increasing southwesterly winds in early winter. This might also be related to a long-term change in the North Atlantic Oscillation.     

科尔沁沙地东南缘近3000年来植被演化与人类活动

在科尔沁沙地东南部,以蒙古栎为代表的乔木花粉从３１００ａＢ．Ｐ．开始显著下降,蒿属和藜科等草本植物花粉逐渐上升,藜科花粉开始上升时间又迟于蒿属花粉。这说明,原业的固定沙丘有一部分首先转化为半固定沙丘,半固定沙丘后来又转变成半流动和流动沙丘。     

现代中国人起源的实证──颅骨特征的时空变化

本文用数学方法系统地检测了从早期智人到现代人时期中国人颅骨测量性特征的时空变化规律。结果显示,从早期智人到晚期智人的演化过程出现逆向变化、不连续;同时,长江以北的和长江以南的颅骨特征时态变化趋势也呈现显著差异。这两种现象的存在,揭示了现代北方的和南方的中国人可能由各自地区的早期智人演化而来。     

海陆边缘沉积磷在全球变化研究中的意义

从磷的生物地球化学循环的角度,讨论了磷与大气圈O2、CO2的关联模式,并通过研究磷的环境地球化学行为,揭示了海陆边缘沉积磷对古气候、古环境变化的记录及其对指示古全球变化的关键性,同时提出了中国东部沿海近代沉积磷的积累与全球变化的耦合作用关系,在中短时间尺度的全球变化研究中所具有的特殊意义。     

长江中下游降水异常特征及其与全国降水和气温异常的关系

利用１９５１－１９９８年中国１６０站逐月降水和气温资料,分析了长江中下游降水异常的基本特征,并着重分析了它与全国其他地区降水和气温异常的关系。结果表明：长江中下游降水异常有明显的季节,年际和年代际变化特征、６－７月降水异常程度大,频数多,以７月为最;在近４８年中,该地区的降水异常表现为３个明显不同的气候时段,可选出１０个涝年和８个旱年。     

RIVERS' FEATURES ON ALLUVIAL FANS IN NORTHWEST CHINA

IINTRODUCTIONAlluvialfanisakindofsedimentogeniclandform,whichisdevelopedwhereriverflowsoutofmountain.Holdingapositionalongfootsofmostmountains,itconstittltestheimportantpartofthefluvialsedimentarysystem.Hooke(1967)describedtraditionalriverformonalluvialfans.Riversinciseandformdeepstableandunstablechannelsonupperpartsofalluvialfans.Andbelowtheintersectionpoints,riversflowoutofthevalleysinformofbraidedchannelanddepositsmallsecondaryajlluvialfansonthesurfaceofthefan.Lobeck(1939,fromRochocki…     

青藏高原北部地区强震演化过程研究

研究了青藏高原北部地区≥ 7级地震时空分布特征、孕育演化过程,并探讨了物理解释。结果表明,本地区≥ 7级地震空间上受区内主要活动断裂控制,发震间隔时间具有一定的规律性;同时,本地区≥ 7级地震的孕震演化过程具有共性行为,表现为孕震构造10年尺度的大范围中强震平静,研究区2～ 5年尺度的中强震频发,末次中强震的时空任意性等特征,对区域地震分析预报具有实用价值。     

地震活动中短期预测指标研究及其应用

在研究应用模糊地震学和统计地震学某些方法的基础上,通过实际预报检验,对一些中短期预报较好的方法,如地震活动平静异常μｑ值,自相似从属函数μｓ值,自助统计方差σ值进行深入研究,探索孕震后期地震活动图像演化特征。