Test area of the SAGE survey

Sky surveys represent one of the most important efforts to improve developments in astrophysics,especially when using new photometric bands. We are performing the Stellar Abundance and Galactic Evolution(SAGE) survey with a self-designed SAGE photometric system, which is composed of eight photometric bands. The project mainly aims to study the stellar atmospheric parameters of ～0.5 billion stars in ～12 000 deg2 of the northern sky, which mainly focuses on Galactic astronomy, as well as some aspects of extragalactic astronomy. This work introduces the detailed data reduction process of the test field NGC 6791, including the data reduction of single-exposure images and stacked multi-exposure images, and properties of the final catalog.     

德国迁都柏林过程中的地球信息技术─-祝贺陈述彭院士2000年2月14日八十华诞生日快乐

联邦德国议会1991年决定, 议会与政府核心部门在2000年前从波恩迁回柏林 ,波恩保留联邦行政管理中心的功能。为了按时准确地规划和完成落实迁都建设工程,在柏林建设国家行政办公设施和国家工作人员生活居住设施,解决波恩地区因国家机关迁离而遭受的损失,参加建设的许多部门应用了地球信息技术。文中介绍了“柏林房地产信息系统”,“联邦议会与政府核心区建设信息系统”,“物业管理信息系统”,“波恩地区经济地理信息系统”以及地球信息技术在交通和环境管理中的应用。     

滨海含水层胶体絮凝导致地层损害的实验研究

滨海含水层地层损害是指淡水驱替咸水过程中,释放后的黏土胶体发生絮凝沉降,导致地层孔隙被堵塞,引起含水介质的渗透性降低的现象。该文通过絮凝沉降实验和定流速砂柱实验,分析不同离子强度和阳离子价态(一价、二价)对胶体絮凝沉降的影响,结果表明:NaCl作为电解质时,絮凝发生的离子强度范围在0.032~0.034 mol/L之间,絮凝时间从82 min减少至39 min;而电解质为CaCl 2,离子强度为0.006 mol/L时,胶体的絮凝时间仅需6 min;钙钠比越高,黏粒絮凝发生的越快。砂柱实验结果显示,含水介质渗透性会随着电解质溶液的离子强度增加和阳离子价态的升高快速降低。当电解质为NaCl,离子强度分别为0.054 mol/L和0.017 mol/L时,含水介质渗透性降低20%所需时间分别为15 min和50 min;当电解质为CaCl2,离子强度为0.011 mol/L时,含水介质渗透性降低20%仅需5 min。因为高离子强度和高价阳离子可以加速胶体絮凝,多孔介质的孔吼更容易发生堵塞,研究成果对降低滨海含水层的地层损害有一定的实际应用价值。     

乌鲁木齐市边界层日变化特征

利用乌鲁木齐市晴天CFL-03型风廓线雷达观测资料,分析了边界层日变化特征。得出结论如下:边界层结构季节变化明显。冬、春季300~600m以下风速较小,小于3m/s,且愈近地面风速愈小;以上风速大、风向恒定,基本为东南大风。夏季和秋季风速比冬季和春季小,流场特征较复杂,水平风速和风向变化较活跃,存在明显的风切变。折射率结构常数春、秋和冬季比夏季分别小1个、3个和1~3个量级;夏季最大,集中在10~(-16)~10~(-13) m~(-2/3)之间。春、夏和秋季晴天湍流动能耗散率量级分别在10~(-6)~10~(-2) m~2·s~(-3)、10~(-4)~10~(-3) m~2·s~(-3)、10~(-6)~10~(-3) m~2·s~(-3)之间;白天比夜间约大1个量级。晴天折射率结构常数和湍流动能耗散率日变化特征与风场日变化特征有较好地对应关系,即湍流发展旺盛的区域与风速较大的区域相一致。风廓线雷达资料反演的湍流动能耗散率对春季和夏季边界层结构日变化演变特征的监测较好。夏季夜间稳定边界层约400~500m,残余层可达到约1800m,对流边界层可发展到约2500m,混合层约2200m,夹卷层约300~400m。     

A Test on Two Codes for Extrapolating Solar Linear Force-free Magnetic Fields

We evaluate the performances of two newly-implemented codes for extrapolating the solar linear force-free magnetic fields, by measuring their quantified responses to the lower boundary vector field data on a finite region using analytical models. The codes are based on two boundary integral formulas with different mechanisms in utilizing the transverse boundary field: the first one only utilizes the transverse boundary field to derive the value of the force-free parameter, while the other one explicitly utilizes the whole transverse boundary field, in addition to the vertical field component. Studies on the test cases show that both of the codes could reproduce the analytical model fields with reasonable accuracy within the valid domain, provided a sufficient amount of data is available at the lower boundary. The code utilizing explicitly all three components of the boundary field shows generally better performances and requires a smaller boundary-data area in order to achieve the same degree of accuracy in the metric quantities such as the normalized vector error, vector correlation, vector angular difference, and magnetic energy; however, the accuracy in the divergence-free metric and especially the force-free metric are less ideal.     

地震监测SAR卫星需求分析与轨道设计

通过对SAR卫星在地震监测任务中的需求分析。确定者这种卫星应该具备干涉和大视角两种工作模式。并利用太阳同步准回归轨道设计方法初步进行了地震监测SAR卫星的轨道设计。     

Application of a multi‐temporal,LiDAR‐derived,digital terrain model in a landslide‐volume estimation

Sediments produced by landslides are crucial in the sediment yield of a catchment, debris flow forecasting, and related hazard assessment. On a regional scale, however, it is difficult and time consuming to measure the volumes of such sediment. This paper uses a LiDAR‐derived digital terrain model (DTM) taken in 2005 and 2010 (at 2 m resolution) to accurately obtain landslide‐induced sediment volumes that resulted from a single catastrophic typhoon event in a heavily forested mountainous area of Taiwan. The landslides induced by Typhoon Morakot are mapped by comparison of 25 cm resolution aerial photographs taken before and after the typhoon in an 83.6 km² study area. Each landslide volume is calculated by subtraction of the 2005 DTM from the 2010 DTM, and the scaling relationship between landslide area and its volume are further regressed. The relationship between volume and area are also determined for all the disturbed areas (V_L = 0.452A_L^1.242) and for the crown areas of the landslides (V_L = 2.510A_L^1.206). The uncertainty in estimated volume caused by use of the LiDAR DTMs is discussed, and the error in absolute volume estimation for landslides with an area >10⁵ m² is within 20%. The volume–area relationship obtained in this study is also validated in 11 small to medium‐sized catchments located outside the study area, and there is good agreement between the calculation from DTMs and the regression formula. By comparison of debris volumes estimated in this study with previous work, it is found that a wider volume variation exists that is directly proportional to the landslide area, especially under a higher scaling exponent. Copyright © 2013 John Wiley & Sons, Ltd.     

中国地震台网震级的对比

采用线性回归和正交回归方法,利用中国地震台网1983-2004年的观测资料,对中国地震局地球物理研究所测定的地方性震级ML、面波震级MS与MS7、长周期体波震级mB、短周期体波震级mb进行对比,给出了它们之间的经验关系式.研究结果表明:①由于不同的震级标度反映了地震波在不同周期范围内辐射地震波能量的大小,因此对于不同大小的地震,使用不同的震级标度更能客观地描述地震的大小.当震中距小于1 000 km时,用地方性震级ML可以较好地测定近震的震级.当地震的震级M＜4.5时,各种震级标度之间相差不大.当4.5＜M＜6.0时,mB＞MS,MS标度低估了较小地震的震级,因此用mB可以较好地测定较小地震的震级.当M＞6.0时,MS＞mB＞mb,mB与mb标度均低估了较大地震的震级,用MS可以较好地测定出较大地震(6.0＜M＜8.5)的震级.当M＞8.5时,MS出现饱和现象,不能正确地反映大地震的大小;②在我国境内,当震中距＜1 000 km时,ML与区域面波震级MS基本一致,在实际应用中无需对它们进行震级的换算;③虽然MS与MS7同为面波震级,但由于所使用的仪器和计算公式不同,MS比MS7系统地偏高0.2～0.3级;④对于长周期体波震级mB和短周期体波震级mb,虽然使用的计算公式相同,但由于使用的地震波周期不同,对于mB=4.0左右的地震,mB与mb几乎相等,而对于mB≥4.5的地震,则mB＞mb.     

云南地区近期强震重复发生时地震学的动态演化特征

通过地强震重复发生的滇西北、滇东北、滇西南澜沧江以西３个地震区多项地震活动性和地震波参数的动态追踪，发现在同一地震区重复发生的强震，震前的异常形态可以具有相惟性，反向变化的特征。如滇东北地区中小地震在１９８５年禄劝强震前的活跃和１９９５年武定强震前的平静；澜沧地震叶波速比月均值在１９８８年澜沧－－耿马大震前的低值异常和１９９５年孟连西中缅边境大震前的高值异常。本同时以ｂ值和波速比为例，讨论了强震     

干旱区啤酒花农艺性状与品质的关系

明确啤酒花农艺性状与品质的相关性,可以为啤酒花种质资源优选鉴定提供依据。分析了甘肃省河西地区引进的50份啤酒花种质材料单蔓花数、花穗长、花穗粗、单花重、百花重、干鲜比与产量和品质的关系。结果表明：干旱半干旱地区啤酒花种质资源农艺性状和品质指标均存在较大变异,为优异资源的筛选创造了条件。农艺性状和品质指标存在一定相关性,其中,花穗粗和单花重均与干鲜比显著正相关（R²=0.293和R²=0.288）,花穗长和干鲜比与黄腐酚含量呈极显著正相关且干鲜比对黄腐酚含量贡献大于花穗长,而6个主要农艺性状均与α-酸含量无显著相关性。花穗长、花穗粗可以作为干鲜比大、产量和黄腐酚含量高、药用价值好的啤酒花种质资源筛选的农艺性状指标,但高α-酸含量的啤酒花种质资源无法通过农艺性状去筛选。