The investigation of Moskalenko's 1959 optical transient field inside GRB791101 error box

We report the results of an optical study of Moskalenko's OT 1959 field. The deep CCD images were obtained at the 6-m telescope of SAO RAS on June 8/9 1994. The BVR photometry of objects near the position of Moskalenko's OT 1959 are presented. An object with V= 23.43 and peculiar colours B-V= 0.9 and V-R= 1.10 was found. It is a possible candidate for the 1959 optical flash.     

合肥地区一次小雨过程的W波段云雷达 的云物理特征分析

利用我国自己研制的W波段云雷达地基探测资料,分析了合肥一次小雨云系的微物理过程,然后利用两个不同地区的地基及机载探测资料,初步反演了水云及卷云的微物理参数。结果表明:(1)回波强度增大,多普勒速度、线性退极化比(LDR)、谱宽激增的地方为融化层顶,根据LDR亮带可初步判定融化层的厚度;(2)利用经验关系法,对卷云冰水含量和水云的液态水含量进行了反演,利用推导的公式反演得到冰晶云云粒子的有效半径;(3)利用逐库订正法对水云的回波强度进行订正,得到了衰减订正后的液态水含量,减小了反演误差。     

Control of active faults and sea level changes on the distribution of shallow gas accumulations and gas-related seismic structures along the central branch of the North Anatolian Fault,southern Marmara shelf,Turkey

Detailed reviews of multichannel seismic reflection, sparker, chirp and multibeam data that were collected on the southern Marmara Sea shelf revealed various shallow gas indicators and related sedimentary structures, including enhanced reflections, seismic chimneys, acoustic blanking, bright spots, pockmarks, mound-like features and seeps. Seismic attribute analyses were applied to characterise the existence of gas-bearing sediments. The distribution of shallow gas indicators provides important insights into their origin and the geological factors that control them. Prominent gas accumulations and seeps are observed along the profiles that cross the branches of the central segment of the North Anatolian Fault Zone, which indicates that the gas seeps are controlled by active faulting. This indicates that the faults act as conduits through the sedimentary column. The dense occurrences of gas directly off the river mouths along the shallow bays provide clues about the organic-rich carbon content of the sediments and biogenic methane generation. In some areas, the gas-related acoustic anomalies are mostly located in the upper sediments below the marine unit, which indicates that the gas emissions in these areas were terminated as a result of the increased overburden pressure after the Holocene sea level rise and the deposition of the marine unit.     

C-FMCW雷达对江淮降水云零度层亮带探测研究

不同于体扫雷达探测降水系统,垂直指向雷达可探测降水云中粒子垂直演变的微物理过程。C波段调频连续波垂直指向雷达 (C-FMCW) 采用收发分置天线,数据垂直分辨率达15~30 m,时间分辨率达2~3 s,利用其2013年6—8月在安徽定远探测数据对降水云垂直结构特征及亮带中融化微物理过程进行研究。6次降水过程共计46 h中的39.1%数据具有清晰的亮带结构特征,期间降水占地面总降水量的15%;江淮雨季层状云、对流云和混合性降水系统中均出现零度层亮带,层状云中亮带长时间维持,对流降水系统移出后减弱阶段的亮带结构稳定,混合降水系统中的对流扰动加强冲破了亮带结构。以融化层中最大回波强度Z_p所在高度进行融化层的粒子碰并增长和破碎减弱分层分析,上半层融化过程主要表现为碰并增长,下半层则是粒子破碎减弱。剔除了介电常数、下降速度引起的粒子浓度改变影响后,层状云和对流降水后期的回波强度加强表明融化增长程度接近,后者略强,混合降水云的融化增长最强。     

Shallow Decay of X-ray Afterglows in Short GRBs： Energy Injection from a Millisecond Magnetar？

With the successful launch of Swift satellite,more and more data of early X-ray afterglows from short gamma-ray bursts have been collected.Some interesting features such as unusual afterglow light curves and unexpected X-ray flares are revealed.Especially,in some cases,there is a fiat segment in the X-ray afterglow light curve.Here we present a simplified model in which we believe that the flattening part is due to energy injection from the central engine.We assume that this energy injection arises from the magnetic dipole radiation of a millisecond pulsar formed after the merger of two neutron stars.We check this model with the short GRB 060313.Our numerical results suggest that energy injection from a millisecond magnetar could make part of the X-ray afterglow light curve flat.     

基于微雨雷达的六盘山区地形云降水宏微观特征观测分析

利用2017年6—11月宁夏六盘山区收集的微雨雷达和微波辐射计等探测资料,对比分析了六盘山区山脊和山谷对流云降水、层状云和浅积云降水过程中的云微物理特征及亮带,针对典型层状云降水事件山脊和山谷站的亮带及以下各层的雨滴谱分布特征,探索了亮带以上几层水凝物的分类。结果发现:六盘山区三类降水云山脊的反射率及反射率衰减程度均高于山谷,表明地形强迫使得山脊降水云的物理和动力过程较山谷更剧烈,层状云降水过程中山脊0℃等温线以上的反射率明显高于山谷,表明山脊在0℃等温线以上有更多水凝物。分析一次典型层状云降水过程发现:六盘山区降水液滴自亮带下落的过程中,碰并过程占主导;亮带以下各层DSD符合Gamma分布,山脊站Gamma分布的相关性比山谷站强且拟合优度更优;降水开始的前3 min,推测-4～0℃等温线之间的水凝物主要是霰,此后水凝物主要是雪颗粒和霰,而山谷在降水开始的前5 min,-4～0℃等温线层之间的水凝物主要是雪颗粒和较大的霰,此后水凝物主要是霰。     

巴彦浩特盆地烃渗漏蚀变带"磁亮点"的识别

采用多层组合棱柱体建立了磁性蚀变带磁场正演模型,并分析了由它产生的“磁亮点”的特征,运用“磁亮点”的宽度和异常幅值特征构制的滤波器,提取了7个可能与烃运移有关的“磁亮点”。结合地质与伽马能谱测量资料的分析得出,其中的2个“磁亮点”位于含油地层石炭系较厚的凹中隆和山前断阶带,且该区也有放射性低值异常显示,是值得进一步工作的油气远景区。     

二十一世纪的地震勘探技术

2 1世纪 ,地震勘探技术将进一步发展 ,三维地震的主流技术地位仍不可动摇 ,提高三维地震的分辨率是进一步提高三维地震解决地质问题能力的主要发展方向。三维叠前深度偏移技术将进一步发展并成为常规处理技术 ,全三维可视化解释将使三维地震信息得到更充分的利用。多波地震将全面应用于油气勘探。该项技术的应用 ,将使地震勘探技术从构造勘探真正推向岩性勘探 ,推向直接找油找气。时间延迟地震标志着开发地震已走向实用 ,其技术的发展有赖于三维地震技术发展     

青藏高原零度层亮带的识别订正方法及在雷达估测降水中的应用

零度层亮带是指雪花或冰晶降落到零度层附近,表面发生融化而使雷达反射率突然增大的现象.它是影响雷达资料质量的重要因素,常会导致雷达估测降水的高估.青藏高原海拔高、零度层低,零度层以下的降水范围非常有限,亮带对青藏高原地区的雷达估测降水的影响更加显著.因此,对亮带进行自动识别订正,对提高青藏高原雷达降水估测的精度有重要意义.本文在考虑青藏高原遮挡严重的情况下,通过计算反射率垂直廓线来识别零度层亮带,对亮带区域进行订正,并将亮带订正前后的混合扫描反射率分别估测降水,分析亮带订正对降水估测误差的影响.结果表明:雷达识别的亮带高度在探空资料零度层以下几百米内;亮带订正前,反射率垂直廓线在零度层附近有显著弯曲,雷达对降水的估测明显偏高;亮带订正后,反射率垂直廓线在零度层附近的显著弯曲消失,雷达估测的降水量与雨量计的观测值较一致,降水估测误差比订正前明显减小.