桑沟湾沉积碳库年汇入速率的长期变化及其区域性差异

对取自桑沟湾北西南三根柱样近200 a碳来源及埋藏通量的解析,分析了湾内不同站位各形态碳的差异性,进而对全湾碳埋藏进行了估算。湾内环流、贝藻养殖等造成湾内不同区域碳埋藏的差异;桑沟湾总碳（TC）平均量1.79%,有机碳（TOC）平均量0.54%,无机碳（TIC）平均量1.25%,TOC含量相对较小,为海陆混合来源,以陆源有机碳（C_t）为主,大规模人工养殖后,海源有机碳（C_a）有明显增加的趋势。桑沟湾碳埋藏通量平均为228.9 g/（m2·a）,以无机碳为主要埋藏形式（约占70%）,高的沉积速率及生物残骸沉降使桑沟湾养殖区碳的来源及埋藏区别于其他陆架海域。     

Magnetic Twist and Writhe of δ Active Regions

We have selected 104 active regions with a δ magnetic configuration from 1996 to 2002 to study how important a role the kink instability plays in such active regions. In this study, we employ the systematic tilt angle of each active region as a proxy for the writhe of a flux tube and the force-free parameter, α_best, as a proxy for the magnetic field twist in the flux tube. It is found that 65–67% of the active regions have the same sign of twist and writhe. About 34% (32%) of the active regions violate (follow) the Hale-Nicholson and Joy's Laws (HNJL) but follow (violate) the hemispheric helicity rule (HHR). Sixty-one (61) of the 104 active regions studied each produced more than five large flares. Active regions violating HNJL, but following HHR, have a much stronger tendency to produce X-class flares and/or strong proton events. Comparing with previous studies for active regions with well-defined (simpler) bipolar magnetic configuration, it is found that the numbers following both HNJL and HHR are significantly lower in the δ-configuration case, while numbers violating one of the laws and the rule significantly increase with the increase of the magnetic complexity of the active regions. These results support the prediction for the presence of a kink instability, that the twist and writhe of the magnetic fields exhibit the same sign for δ active regions (Linton et al., Astrophys. J. 507, 40, 1998, Astrophys. J. 522, 1205, 1999; Fan et al., Astrophys. J. 521, 460, 1999). Finally, we analyze possible origins of the twist and writhe of the magnetic fields for the active regions studied.     

A Statistical Study of Rapid Sunspot Structure Change Associated with Flares

We reported recently some rapid changes of sunspot structure in white-light(WL) associated with major flares.We extend the study to smaller events and present here results of a statistical study of this phenomenon.In total,we investigate 403 events from 1998 May 9 to 2004 July 17,including 40 X-class,174 M-class,and 189 C-class flares.By monitoring the structure of the flaring active regions using the WL observations from the Transition Region and Coronal Explorer(TRACE),we find that segments in the outer sunspot structure decayed rapidly right after many flares;and that,on the other hand,the central part of sunspots near the flare-associated magnetic neutral line became darkened.These rapid and permanent changes are evidenced in the time profiles of WL mean intensity and are not likely resulted from the flare emissions.Our study further shows that the outer sunspot structure decay as well as the central structure darkening are more likely to be detected in larger solar flares.For X-class flares,over 40% events show distinct sunspot structure change.For M-and C-class flares,this percentage drops to 17% and 10%,respectively.The results of this statistical study support our previously proposed reconnection picture,i.e.,the flare-related magnetic fields evolve from a highly inclined to a more vertical configuration.     

横断山脉地区大气环流演变特征分析

应用Lamb-Jenkinson大气环流分型方法对横断山脉地区的8个经度×10个纬度范围内1948-2012年逐日平均的海平面气压场进行环流分型,由日平均海平面气压场算出6个环流指数（u、v、V、ξu、ξv、ξ）,并由此划分出27种不同的环流型。分型结果表明：横断山脉地区主要环流分型为E型、NE型、SE型、N型和C型,其频率分别为：21.4%、14.6%、13.7%、9.8%和9.5%;E和NE型环流频率逐渐增加,C型环流型频率逐渐减少。春季横断山脉地区主导环流比较繁琐;NE、N型为夏季的主要环流型,但E型环流在夏季的频率也相当大;秋季和冬季横断山脉地区的主导环流型都为E型和SE型。夏季主导环流型持续时间较长,冬季也是主导环流持续的时间较长,个别年份主导环流型持续时间超过了一个月,这主要与横断山脉地区复杂的地形有联系。     

Observations of Giant Pulses of the Crab Pulsar

The Crab Pulsar was observed at 1540 MHz with the 25m radio telescope at Urumqi with a filterbank de-dispersion backend. A total of 2436 giant pulses with pulse energies larger than 4300 Jy μs were detected in two observing sets. All of these giant pulses are located in the main pulse (MP) and inter pulse (IP) windows of the average profile of the Crab Pulsar. The ratio of the numbers of giant pulses detected in the IP and MP windows is about 0.05. Our results show that, at 1540 MHz, the emission in the IP is contributed by giant and normal pulses, while that in the MP is almost dominated by giant pulses. The distribution of energy of the 2436 giant pulses at 1540 MHz can be described by a power-law with index α=3.13±0.09. The intrinsic threshold of giant pulse energy in the MP window is about 1400 Jy μs at 1540 MHz.     

国家地震速报备份系统的部署与运行

国家地震速报备份系统是由中国地震局出资,在广东省地震台网中心建设的一套全自动地震速报系统.本文介绍了国家地震速报备份系统的职责、系统架构、主要功能模块、系统工作原理、部署情况与台网规模,分析了系统2009-2010年运行两年来的工作情况,并对系统自动产出的地震定位结果进行初步的统计与比较,对系统运行的总体效果给予了初步...     

Single-Link Cluster Method to Identify Foreshocks and Aftershocks

Based on Single-Link Cluster (SLC) analysis,a new method to identify the foreshocks andaftershocks of a strong shock from the earthquake catalogue and then to form a sequencecatalogue has been proposed in this paper.In the SLC frame,there are many chains formedby links with lengths shorter than or equal to the characteristic length Lc.It is defined thatwhen some of these chains connect with a strong shock,the seismic events on such chainsfirm a sequence with the strong shock.In this sequence,the strong shock is the main shock;the events preceding the main shock are foreshocks and those following the main shock areaftershocks.By using this method,the foreshocks and aftershocks associated with the M_s7.4Haicheng earthquake and with the strong shocks of M_s≥6.0 in the top area of Kunlun-AltunArc were identified and sequence catalogues for these strong shocks were set up.     

Detrital Zircon Dating of Meso- and Neoproterozoic Rocks in North China and Its Implications

New dates from Meso- and Neoproterozoic strata contribute to the recently defined Precambrian stratigraphical timescale of China agreed by the Subcommission on the Precambrian System, and the National Commission on Stratigraphy of China on Nov. 24, 2009. First, the age range of the Changcheng System, including the Changzhougou, Chuanlinggou, Tuanshanzi and Dahongyu formations has been constrained to 1.8–1.6 Ga. Second, the Jixian System including the Gaoyuzhuang, Yangzhuang, Wumishan, Hongshuizhuang and Tieling formations has been constrained to 1.6–1.4 Ga. Third, an as-yet unnamed (undefined) system (1.4–1.0 Ga) is only developed in the Xiamaling Formation at the Jixian section, Tianjing. Fourth, the Qingbaikou System, including the Luotuoling and Jing’eryu formations has been constrained to 1.0–0.78 Ga. Fifth, the Nanhuan System ranges between 780–635 Ma, and the Sinian System is within 635–542 Ma. However, according to a series of SHRIMP U-Pb dates from the late Precambrian in the Jiangnan Orogen Belt in South China Platform, the constrained strata will be redefined as in the upper part of the Qingbaikou System. To aid global geodynamics, it is useful to denote a late Precambrian section with unified, precise and high-precision chronological dating; this is here defined in North China Block and Jiaoliao-Korean Block. However, the Neoproterozoic Qingbaikou study in North China will be influence in whole Meso- and Neoproterozoic in the Jiangnan Orogenic Belt in between the Yangtze Block and the Cathaysia Block in South China.     

中国第四纪研究的若干问题

在第四纪研究方面,2001年上半年有两次国际学术讨论会在中国召开。一次是5月9～11日在北京召开的“亚洲季风研讨会”（Symposium on Asaia Monsoon）,由汪品先院士主持;另一次是5月15～17日在西安召开的“环境变迁中的人类尺度和自然过程”（Conference of Human Dimensions and Natural Processes in Environmental Change）,由安芷生院士主持。会议的论文和总结将正式出版。十分感谢主持人的邀请,我参加了这两次盛会,学习到很多新知识。除此之外,也有一些感想,提出来作为参考。     

水下机动目标轨迹跟踪的自适应估计方法

研究了用GPS测定基阵坐标,分析了水听器基阵所接收到的声脉冲信号的处理。通过模拟和实测数据的试算,证明了本文提出的模型及方法不但能处理多系统含有粗差的观测值,而且具有良好的跟踪处理机动目标的性能。