Land water storage contribution to sea level from GRACE geoid data over 2003–2006

Seasonal and inter-annual change in land water storage (expressed in terms of water volume change) over 27 large river basins worldwide are estimated from monthly GRACE geoids solutions computed at GFZ from February 2003 to February 2006. The largest annual water volume change is found in the Amazon basin, followed by the Parana, Ob, Orinoco, Tocantins, Niger, Congo, Ganges, Mekong, and Brahmaputra. In terms of trend over the 3-year period, positive and negative values are observed but in a number of cases computed trends are at the noise level. However significant negative trends are found in the Amazon, Ganges, Mississippi, Nile, Parana, and Zambezi basins, indicating water mass loss over that period. Positive trends (water mass gain) are marginally significant. We have computed the land water contribution to sea level change. On average over the 3-year time span, we find that the net effect is positive (net loss of water in terrestrial reservoirs), on the order of 0.19 +/− 0.06 mm/yr. If sustained over a longer time span than considered here, such a value may become comparable to the ice sheets contribution to sea level rise.     

Formation of Transient Coronal Holes during the Eruption of a Quiescent Filament and its Overlying Sigmoid

By using Hα, He I 10830, EUV and soft X-ray (SXR) data, we examined a filament eruption that occurred on a quiet-sun region near the center of the solar disk on 2006 January 12, which disturbed a sigmoid overlying the filament channel observed by the GOES-12 SXR Imager (SXI), and led to the eruption of the sigmoid. The event was associated with a partial halo coronal mass ejection (CME) observed by the Large Angle and Spectrometric Coronagraphs (LASCO) on board the Solar and Heliospheric Observatory (SOHO), and resulted in the formation of two flare-like ribbons, post-eruption coronal loops, and two transient coronal holes (TCHs), but there were no significantly recorded GOES or Hα flares corresponding to the eruption. The two TCHs were dominated by opposite magnetic polarities and were located on the two ends of the eruptive sigmoid. They showed similar locations and shapes in He Ⅰ 10830, EUV and SXR observations. During the early eruption phase, brightenings first appeared on the locations of the two subsequent TCHs, which could be clearly identified on He Ⅰ 10830, EUV and SXR images. This eruption could be explained by the magnetic flux rope model, and the two TCHs were likely to be the feet of the flux rope.     

On the magnitude and direction of the anisotropy of galactic cosmic rays

The results of measuring the diurnal cosmic-ray intensity variations in the energy range 1–100 TeV are discussed. Whereas the phase of the first harmonic of the sidereal daily wave directly determines the phase (right ascension) of the cosmic-ray anisotropy vector, the amplitude and declination of the true anisotropy cannot be reconstructed directly from the amplitude of the first harmonic. However, they can be determined by invoking data on the zero harmonic. The results of some recent experiments purporting to measure the cosmic-ray anisotropy with a particularly high accuracy are shown to be interpreted erroneously.     

天山南坡科其卡尔巴契冰川消融期气候特征分析

通过分析天山南坡科其卡尔巴契冰川区的气候变化特征及其对冰川消融变化过程的影响, 研究了冰川对气候变化的响应机理及其对塔里木河水资源的影响规律.科其卡尔巴契冰川区夏季气温比较高, 基本处于正温, 日较差较小; 气温直减率较小, 平均值为0.60·℃\5(100m)-1, 冰川冷效应不明显; 对流性降水较多, 降水量的75%发生在白天; 冰川区局地环流--山谷风发育, 海拔3 900 m以上冰川受西风环流影响显著; 净辐射在7月和8月中上旬均较大, 在8月下旬后净辐射开始逐渐减小, 与冰川消融是一致的. 7月初至7月下旬是消融较强的两个时段, 冰川平均消融速率为38.66 mm·5d-1, 到8月中旬消融速率略有降低, 平均为34.79 mm·d-1, 至9月中旬降至28.83 mm·d-1.     

当代生物多样性剧减与古-中生代之交生物绝灭的对比

18世纪以来人类活动对环境造成了强烈破坏,给生物多样性带来了巨大损失.为了了解生物多样性的变化趋势,利用"绝灭物种统计法"、"种-区曲线法"和化石记录对400年以来的生物多样性和古-中生代之交的生物绝灭进行了分析.当代生物多样性剧减表现为物种的快速绝灭(从8×104种/Ma增大到1.2×106种/Ma),而属的绝灭几乎为0;古-中生代之交生物绝灭的初始阶段也表现为物种的快速绝灭(从40种/Ma增大到150种/Ma),并且这个阶段的属的绝灭速率远低于绝灭高峰阶段的相应值(即66属/Ma远小于465属/Ma),可见当代生物多样性剧减相当于二叠-三叠系之交生物绝灭的初始阶段.     

新疆雅满苏铁矿床地空高光谱异常特征及应用

正雅满苏铁矿床位处东天山成矿带,成矿地质条件优越。前人在矿床的成矿规律、地球化学、矿床类型、流体来源等方面,开展了较多科研工作(李厚民等,2014;王兴保,2005)。但在遥感地质方面的研究和应用工作还未开展。铁矿床及外围区域属准平原状丘陵地貌,基岩出露,地表蚀变信息丰富,可获取高质量的地空高光谱遥感数据,有利于发挥高光谱遥感的技术优势。     

高放废物地质处置阿拉善预选区巴彦诺日公地段目标深度岩体质量预测

高放废物地质处置阿拉善预选区巴彦诺日公地段位于阿拉善地块东部,主要由二叠纪侵入的花岗岩构成,地壳次稳定。通过踏勘,确定了2个钻孔,布置了若干条物探剖面。以这2个钻孔为中心,在17km×17km范围内进行了工程地质测绘,获得了地表结构面分布特征。地表岩体质量以III级岩体为主,地表以下3m~4m处多为I级和II级岩体。根据钻孔岩芯编录和力学试验数据,对岩芯质量进行评价,岩芯整体质量较好,以Ⅰ级和Ⅱ级岩体为主。对比岩体质量和测井数据,发现岩体质量与岩体的物理参数具有明显的相关性。通过和CSAMT剖面上对应位置的对比,建立了岩体质量与电阻率的关系。结合地表岩体质量、钻孔岩芯质量和物探剖面,对目标深度岩体进行了预测：目标深度（600m深左右）岩体质量以Ⅰ级岩体为主,局部有Ⅱ级岩体和Ⅲ岩体。     

豫西寨凹隐伏岩体地球物理场特征与深部找矿预测

寨凹隐伏岩体是豫西南地区利用重磁资料解释推断的8个隐伏、半隐伏岩体之一,分布面积约310km2。豫西南地区主要钼（钨）铅锌银（金）矿床均分布于这8个隐伏、半隐伏岩体区及其边部附近,二者具有非常明显的时空关系。研究隐伏岩体分布形态、深度、产状和深大断裂构造分布,对指导深部找矿勘探具有重要意义。通过研究寨凹隐伏岩体重、磁场变化特征和分布规律,并通过相关定量计算,确定了隐伏岩体的侵入模型。将全区隐伏岩体分为三个区,Ⅰ区隐伏岩体顶面深度0~0.8km,分布面积约71km2,Ⅱ区隐伏岩体顶面深度0.8~2.0km,分布面积约153km2,Ⅲ区隐伏岩体顶面深度2~4km,分布面积约86km2。根据隐伏岩体侵入模型和典型矿床物探异常特征,建立了立体成矿模型（从浅至深从中低温成矿元素到高温成矿元素的过渡模型）和综合地球物理找矿模型（包括隐伏岩体、隐伏岩体顶上带、岩钟和斑岩体、矿体矿化体的地球物理异常标志）;预测了找矿潜力,总结了勘查方法技术组合;指出在Ⅰ、Ⅱ隐伏岩体分布区银（金）铅锌矿床的下部有寻找斑岩型钼、钨、铜矿产的潜力。     

基于CryoSat-2雷达高度计数据的南极内陆冰盖高程变化与物质平衡

南极冰盖对海平面影响巨大,高程变化测量是南极物质平衡监测的重要手段。采用欧空局CryoSat-2雷达高度计数据,通过提取卫星升降轨的地面交叉点,监测了南极内陆冰盖的高程变化（物质平衡）。结果表明,后向散射能量对Ku波段的CryoSat-2雷达高度计的高程数据具有一定的影响,经后向散射能量校正后,时间序列上的高程变化变得平缓,高程变化与已有的降雪数据相比,更加符合实际情况。2010年11月至2017年11月南极内陆冰盖高程变化趋势为（-1.1±0.2）cm·a^-1。西南极的Kamb冰流高程变化率为（38.7±1.1）cm·a^-1,Moeller冰流高程变化率为（-10.3±1.2）cm·a^-1,部分Thwaites冰川区域高程变化率为（-13.4±1.8）cm·a^-1,东南极的Wilkes Land出现高下降区,最高达-20 cm·a^-1。Dronning Maud Land虽然出现变化异常的点,但整体并没有显著的高程变化。南极内陆冰盖质量变化为（-10.6±6.2）Gt·a^-1,整体上南极内陆冰盖质量变化平缓,部分区域变化较大,Kamb冰流达到（17.9±0.5）Gt·a^-1,Moeller冰流达到（-3.4±0.4）Gt·a^-1,部分Thwaites冰川区达到（-3.7±0.5）Gt·a^-1。     

1959-2017年天山乌鲁木齐河源1号冰川流域径流及其组分变化

冰川是气候变化的指示器,气候变化对冰川及其径流的影响研究是目前国内外关注的热点和前沿领域之一,目前的研究以模拟为主,实测资料十分有限且不确定性很大。以新疆天山乌鲁木齐河源1号冰川（简称“1号冰川”）流域为例,基于中国科学院天山冰川观测试验站1959-2017年观测数据,研究了中国西部典型小型冰川流域径流及其组分长期变化以及对气候变化的响应,为冰川径流长期变化过程的认识提供重要参考。结果表明,1号冰川流域径流主要由冰川径流和非冰川区降水径流组成,分别占70%和30%。其中冰川径流又可分为冰川区降水径流和冰川融水径流,分别占44%和26%。59年间,冰川径流整体呈上升趋势,在1992年之后出现了一个阶梯式的上升,与气温升高和降水的增加有关,1997-2007年达到高峰,2008年以后出现波动下降趋势,其原因除了与该时段的降水有所减少有关之外,冰川面积减小的影响也不可忽视。另外,还利用实测径流和冰川物质平衡值,通过水量平衡模型,检验了模型使用的冰川区和非冰川区径流系数。