北京区域成矿规律综述

2013～2019年开展的"中国矿产地质志·北京卷"项目是全面总结北京地区现代地质矿产工作,特别是新中国成立以来北京地区矿产勘查与研究成果,旨在全面反映北京市矿产全貌及重要成矿规律。本文是对该项工作部分成果的概括总结。系统收集了北京市铁、金、煤、石灰岩等各类矿产资料,划分了矿种矿床类型,重点对铁、金、煤、石灰岩等矿种成矿地质特征进行了阐述。在全国Ⅰ-Ⅲ级成矿区带划分基础上,结合北京市地质构造演化和成矿特点,提出北京市区域成矿区带划分方案,划分了怀柔北金萤石成矿区、八达岭金铜钼铅锌成矿区、京西煤石灰岩成矿区、密云-怀柔铁金成矿区、密云-平谷金石灰岩成矿区5个Ⅴ级成矿区,总结了不同区带各矿种规律特征。从矿产时空演化、岩浆岩控矿、构造控矿角度进行了区域成矿规律总结,提升了北京地区矿产地质研究水平,填补了北京区域成矿规律多矿种综合性研究的空白。     

湖南寒婆坳矿区热变质煤结构演化及其矿物学特征响应

采用X射线荧光光谱(XRF)、差热分析(DTA)、扫描电子显微镜(SEM)、高分辨透射电镜(HRTEM)、X射线衍射(XRD)和拉曼光谱(Raman)等表征手段对湖南寒婆坳矿区热变质煤的化学组分、物理性质、结构演化与其矿物学特征响应进行了研究。结果表明:岩浆侵入体的热力及构造应力作用促进煤化程度升高逐渐转变为隐晶质石墨,氢、碳原子数目比(H/C)逐渐降低,矿物主要为伊利石、绿泥石、叶蜡石、石英及黄铁矿等;随变质程度增加,真密度升高,孔隙度与电阻率降低;在400℃之后,失重曲线下降缓慢且斜率变小,显示深度裂解与脱落较少。d₀₀₂、L_a、L_c的演化趋势呈非线性变化,显示煤有机大分子结构向石墨化演化的过程中呈现"跃变";隐晶质石墨样品的晶体结构主要为2H型石墨结构,不同程度地含有3R多型,石墨化度为0.47～0.84,石墨晶体轴长a为0.2469～0.2471 nm,c为0.6738～0.6762 nm,晶胞体积V为0.03562～0.03570 nm³,显示靠近岩体晶胞体积减小;随着变质程度升高,L     

城市化对四川盆地夏季气温变化影响的观测和模拟研究

城市化引起的气温上升是土地覆盖变化影响区域气候的重要体现.本文采用"观测资料减去再分析"(Observation Minus Reanalysis,OMR)的方法估计四川盆地和周边地区下垫面城市化改变对夏季地面2 m气温变化趋势的影响.设计了不同城市化下垫面扩展变化的WRF模拟试验,对1998—2012年四川盆地及周边区域夏季逐日平均温度和日最高最低气温进行模拟.在检验模式模拟性能的基础上,利用OMR方法类似的思路定量探讨城市化下垫面对地面气温变化趋势的可能影响.结果显示,(1)基于站点观测资料的OMR分布表明成都、重庆地区的城市下垫面对夏季升温的影响可达0.1℃·a^-1;(2) WRF试验模拟的结果与实际观测接近,能较合理刻画出该地区夏季温度的平均分布及时间变化特征,可以用于该地区城市化区域气候效应的研究;(3)不同城市化进程的模式模拟试验中气温变化趋势的差值与基于站点观测的OMR方法计算得到的结果类似,都证明了重庆和成都的城市下垫面对地面2 m温度的升高具有显著影响,其中在日内低温的表现尤为突出.     

1979年9月19日3B级耀斑光谱分析:金属线的不对称性和线心位移

本文研究了1979年9月19日3B级耀斑金属谱线的不对称性和线心位移.结果表明:强金属线红不对称占主要地位,少数弱金属线也有蓝不对称存在;不对称程度极大发生于线心强度极大之前;不对称性有时可由蓝变红;不管不对称程度如何,线心的位移却很小,总体上仅表现为极微弱的蓝移.文中认为,耀斑爆发时色球压缩区的向下扩展及由此引起的温度极小区上下的物质运动这个动力学过程可基本解释这些观测现象.金属线的研究是对H_α和CaIIK线光谱研究的补充.     

Variations in High-frequency Oscillations of Tropical Cyclones over the Western North Pacific

Variations in the high-frequency oscillations of tropical cyclones(TCs) over the western North Pacific(WNP) are studied in numerical model simulations. Power spectrum analysis of maximum wind speeds at 10 m(MWS_(10)) from an ensemble of15 simulated TCs shows that oscillations are significant for all TCs. The magnitudes of oscillations in MWS_(10) are similar in the WNP and South China Sea(SCS); however, the mean of the averaged significant periods in the SCS(1.93 h) is shorter than that in the open water of the WNP(2.83 h). The shorter period in the SCS is examined through an ensemble of simulations,and a case simulation as well as a sensitivity experiment in which the continent is replaced by ocean for Typhoon Hagupit(2008). The analysis of the convergence efficiency within the boundary layer suggests that the shorter periods in the SCS are possibly due to the stronger terrain effect, which intensifies convergence through greater friction. The enhanced convergence strengthens the disturbance of the gradient and thermal wind balances, and then contributes to the shorter oscillation periods in the SCS.     

Circulation Features Associated with the Record-breaking Typhoon Silence in August 2014

Climatologically, August is the month with the most tropical cyclone(TC) formation over the western North Pacific(WNP) during the typhoon season. In this study, the reason for abnormal TC activity during August is discussed—especially August 2014, when no TCs formed. The large-scale background of August 2014 is presented, with low-level large-scale easterly anomalies and anticyclonic anomalies dominating over the main TC genesis region, a weak monsoon trough system,and a strong WNP subtropical high(WPSH), leading to significantly reduced low-level convergence, upper-level divergence,and mid-level upward motion. These unfavorable large-scale conditions suppressed convection and cyclogenesis. In August2014, equatorial waves were inactive within the negative phase of the Madden–Julian Oscillation(MJO), with fewer tropical disturbances. Although the low-level vorticity and convection of those disturbances were partly promoted by the convective envelopes of equatorial waves, the integral evolution of disturbances, as well as the equatorial waves, were suppressed when propagating into the negative MJO phase. Moreover, the upper-level potential vorticity(PV) streamers associated with anticyclonic Rossby wave breaking events imported extratropical cold and dry air into the tropics. The peripheral tropospheric dryness and enhanced vertical wind shear by PV streamer intrusion combined with the negative MJO phase were responsible for the absence of TC formation over the WNP in August 2014.     

Atmospheric Response to Mesoscale Ocean Eddies over the South China Sea

The South China Sea(SCS) is an eddy-active area. Composite analyses based on 438 mesoscale ocean eddies during 2000–2012 revealed the status of the atmospheric boundary layer is influenced remarkably by such eddies. The results showed cold-core cyclonic(warm-core anticyclonic) eddies tend to cool(warm) the overlying atmosphere and cause surface winds to decelerate(accelerate). More than 5% of the total variance of turbulent heat fluxes, surface wind speed and evaporation rate are induced by mesoscale eddies. Furthermore, mesoscale eddies locally affect the columnar water vapor, cloud liquid water, and rain rate. Dynamical analyses indicated that both variations of atmospheric boundary layer stability and sea level pressure are responsible for atmospheric anomalies over mesoscale eddies. To reveal further details about the mechanisms of atmospheric responses to mesoscale eddies, atmospheric manifestations over a pair of cold and warm eddies in the southwestern SCS were simulated. Eddy-induced heat flux anomalies lead to changes in atmospheric stability. Thus, anomalous turbulence kinetic energy and friction velocity arise over the eddy dipole, which reduce(enhance) the vertical momentum transport over the cold(warm) eddy, resulting in the decrease(increase) of sea surface wind. Diagnoses of the model's momentum balance suggested that wind speed anomalies directly over the eddy dipole are dominated by vertical mixing terms within the atmospheric boundary layer, while wind anomalies on the edges of eddies are produced by atmospheric pressure gradient forces and atmospheric horizontal advection terms.     

中国自然地理学中的气候变化研究前沿进展

气候学是自然地理学的重要组成部分;过去气候变化和当代气候增暖的影响与适应研究是中国自然地理学在气候变化领域的2个主要研究方向。本文综述了这2个研究方向的主要进展,包括：分别简述研究的意义、发展历程与主要科学问题;梳理总结中国过去气候变化重建与时空特征分析,历史时期气候变化的影响,全球增暖背景下中国气候区划变动特征,全球增暖对中国自然生态系统、水资源、农业等方面影响的区域差异,气候变化的综合风险区划等方面的前沿进展,特别是在各方面所取得的主要科学认识;以期为未来的深入研究,特别是编制相关领域和学科发展战略提供参考。     

The Effect of Bioturbation Activity of the Ark Clam Scapharca subcrenata on the Fluxes of Nutrient Exchange at the Sediment–Water Interface

Filter-feeding shellfish are common benthos and significantly affect the biogeochemical cycle in the shallow coastal ecosystems.Ark clam Scapharca subcrenata is one of the widely cultured bivalve species in many coastal areas owing to its tremendous economic value.However,there is little information regarding the effects of the bioturbation of S.subcrenata on the fluxes of nutrient exchange in the sediment-water interface(SWI).In this regard,S.subcrenata was sampled during October 2016 to determine the effects of its bioturbation activity on the nutrient exchange flux of the SWI.The results showed that the biological activity of S.subcrenata could increase the diffusion depth and the rate of the nutrients exchange in the sediments.The bioturbation of S.subcrenata could allow the nutrients to permeate into the surface sediments at 6-10cm and increase the release rate of nutrients at the SWI.The releasing fluxes of DIN and PO43−-P in the culture area were found to be around three times higher than that in the non-cultured region.The culture of S.subcrenata has been proved to be an important contributor to nutrient exchange across the SWI in the farming area of Haizhou Bay.Nutrients exchange in the SWI contributes a part of 86%DIN,71%PO43−-P and 18%SiO32−-Si for the aquaculture farm.     

塔里木盆地轮南油田2、3井区三叠系沉积微相研究

三叠系作为塔里木盆地的主要含油气层系已逐渐被近几年来的油气勘探实践所证实.本文采取综合研究的技术思路和方法,通过取心分析、测井划相,结合开发动态资料,精细刻划各单油砂体在平面及空间上的微相展布.研究表明轮南油田三叠系砂岩,以含砾中粗粒砂岩为主,粒度较粗,重力流沉积特征较突出,以河湖相为主的碎屑岩沉积,其烃源岩主要发育于深湖-半深湖、浅湖和三角洲亚相,从大的韵律到小的层理都显示粒序递变的构造特征,为重力流悬浮搬运沉积的主要标志,存在辫状分支河道微相砂体,分支河道侧缘微相砂体和分支间湾微相砂体三种类型.中上三叠统粗碎屑岩,以及泥岩、粉砂岩,是以半深湖、浅湖至滨岸相环境为主的沉积,自下而上沉积环境分别发育有扇三角洲平原亚相、扇三角洲前缘亚相和前扇三角洲亚相.