全球变暖背景下三亚湾上升流的冷水有利于珊瑚的生存

It has been reported that global warming has negative effects on coral ecosystems in the past 50 years and the effects vary in different ocean environment. In order to make clear the coral reef status in the background of global warming along the south coast of Hainan Island of China, satellite and in situ data are used to retrieve the information of the coral reef status and surrounding environmental factors. The results show that cool water induced by upwelling along the south coast of Hainan Island is found in the area every summer month, especially in the relatively strong El Ni?o years(2002–2003 and 2005). From the NOAA satellite data, degree heating week(DHW) index does not exceed 3 in Sanya Bay even in the relatively strong El Ni?o years. By comparison of a coral reef growth rate in the Sanya Bay with respect to El Ni?o events from 1957 to 2000, coral's growth rate is relatively greater during 1972, 1991–1994 and 1998 El Ni?o event. By analyzing the environmental factors, it is found that the cool water induced by upwelling may be the main reason for protecting corals from global warming effects.     

磁暴期间高纬顶部电离层离子上行特征——DMSP卫星观测

本文利用DMSP F13和F15卫星观测数据,对2001—2005年58个磁暴(-472 nT≤Min.Dst≤-71 nT)期间高纬顶部电离层离子整体上行特征进行了统计研究.观测表明,磁暴期间,顶部电离层离子上行主要发生在极尖区和夜间极光椭圆区.在北半球,磁正午前,高速的离子上行(≥500 m·s^-1)多集中在65° MLat以上;午后,高速离子上行区向低纬度扩展,上行速度要略高于午前;在南半球,磁午夜前,DMSP卫星在考察区域内几乎所有的纬度上都观测到了高速上行的离子;午夜后,各纬度上观测到上行离子的速度明显降低.离子上行期间,DMSP卫星在极区顶部电离层高度上也频繁地观测到电子/离子增温,且电子增温发生的频率要远高于离子增温.O⁺密度变化分析显示,DMSP卫星磁暴期间观测到的上行离子更多地源于顶部电离层高度.这些结果表明电子增温在驱动暴时电离层离子整体上行过程中起着重要作用.     

The effects of asymmetric potential vorticity forcing on the instability of South Asia High and Indian summer monsoon onset

Based on the theory of potential vorticity(PV),the unstable development of the South Asia High(SAH)due to diabatic heating and its impacts on the Indian Summer Monsoon(ISM)onset are studied via a case diagnosis of 1998.The Indian Summer Monsoon onset in 1998 is related to the rapidly strengthening and northward moving of a tropical cyclone originally located in the south of Arabian Sea.It is demonstrated that the rapid enhancement of the cyclone is a consequence of a baroclinic development characterized by the phase-lock of high PV systems in the upper and lower troposphere.Both the intensification of the SAH and the development of the zonal asymmetric PV forcing are forced by the rapidly increasing latent heat released from the heavy rainfall in East Asia and South East Asia after the onsets of the Bay of Bengal(BOB)monsoon and the South China Sea(SCS)monsoon.High PV moves southwards along the intensified northerlies on the eastern side of the SAH and travels westwards on its south side,which can reach its northwest.Such a series of high PV eddies are transported to the west of the SAH continuously,which is the main source of PV anomalies in the upper troposphere over the Arabian Sea from late spring to early summer.A cyclonic curvature on the southwest of the SAH associated with increasing divergence,which forms a strong upper tropospheric pumping,is generated by the anomalous positive PV over the Arabian Sea on 355 K.The cyclone in the lower troposphere moves northwards from low latitudes of the Arabian Sea,and the upper-layer high PV extends downwards and southwards.Baroclinic development thus occurs and the tropical low-pressure system develops into an explosive vortex of the ISM,which leads to the onset of the ISM.In addition,evolution of subtropical anticyclone over the Arabian Peninsula is another important factor contributing to the onset of the ISM.Before the onset,the surface sensible heating on the Arabian Peninsula is very strong.Consequently the subtropical anticyclone which dominated the Arabian Sea in spring retreats westwards to the Arabian Peninsula and intensifies rapidly.The zonal asymmetric PV forcing develops gradually with high PV eddies moving southwards along northerlies on the eastern side of the anticyclone,and a high PV trough is formed in the middle troposphere over the Arabian Sea,which is favorable to the explosive barotropic development of the tropical cyclone into the vortex.Results from this study demonstrate that the ISM onset,which is different from the BOB and the SCS monsoon onset,is a special dynamical as well as thermodynamic process occurring under the condition of fully coupling of the upper,middle,and lower tropospheric circulations.     

利用磷灰石裂变径迹对断层摩擦生热探测或测量的初步探讨

以青藏高原东北缘断裂带为研究对像,对利用磷灰石裂变径迹热年代学对地震断层滑动摩擦生热的探测或测量进行了初步探讨。其基本思路是利用磷灰石裂变径迹热年代计的热敏感,通过对横跨断层垂直方向断层岩和围岩的磷灰石裂变径迹年龄及围限径迹长度分布的对比分析,对断层滑动摩擦生热进行探测。本次研究对来自3个断层剖面的13个样品进行了磷灰石裂变径迹分析,样品包括断层主滑动面上的断层泥、碎裂岩和断层围岩,分析结果并没有获得断层摩擦生热的证据,表明这些断层在地震滑动过程中的摩擦增温非常有限,没有达到磷灰石裂变径迹热年代计体系可加载热信息的温度－时间要求。结合前人已有的相关研究,对利用磷灰石裂变径迹热年代学对地震断层滑动摩擦生热进行探测或测量存在的主要问题及可行性进行了初步总结和探讨,认为只适应于对震级大、断层滑动距离和速率大,摩擦强度强,位于一定深度有大量摩擦热生成,并使断层附近增温达到或超过磷灰石裂变径迹部分或完全退火温度的断层进行滑动摩擦生热的探测或测量,将是一种潜在的能对地震断层滑动摩擦生热或增温进行测量的“热量计或温度计”。     

广西气候与建筑设计

对广西建筑设计所涉及的气候参数进行了计算和分析,给出了南宁、桂林的基本风压、采暖通风和空调室外气象参数和建筑采光系数,为建筑部门提供了科学依据。     

燃烧加热污染空气对超燃冲压发动机性能影响研究

针对燃烧加热地面试验设备存在的工质污染问题,采用数值模拟方法研究了燃烧加热污染空气对氢燃料超燃冲压发动机性能的影响。以飞行马赫数Ma=6.5,当量油气比ER=0.6为计算基准状态,分别对纯净空气和污染空气来流下氢燃料超燃冲压发动机的整机流场和性能进行了对比计算分析。燃烧化学反应模拟采用了改进的H₂/O₂七组分八方程模型,湍流模型为标准的 k-ε模型,并采用直连式燃烧室试验数据进行了数值方法的验证。研究结果表明:(1)相对于纯净空气来流,污染空气来流下的超燃冲压发动机推力和比冲均有所下降。(2)采用酒精燃烧加热器的前提下,来流参数匹配静温、静压、马赫数时,发动机性能与纯净空气来流下的结果最为接近,而匹配总温、总压、马赫数时相差最大。(3)来流参数匹配总焓、静压、马赫数的前提下,采用氢燃烧加热器时发动机性能与纯净空气来流下的结果最为接近,而采用甲烷燃烧加热器时相差最大。      

东风带扰动影响西太平洋副热带高压短期东西向移动的热力强迫分析

利用NCEP/NCAR 1 000～10 hPa 2.5 °×2.5 °日平均再分析资料,分析2003年6月22—25日热带对流层上空东风带扰动影响西太平洋副热带高压（简称西太副高,下同）短期东西进退的热力强迫过程,并探讨了相应机制。结果表明:东风带扰动附近非绝热效应分布和强度的变化影响着西太副高东西向的运动;西太副高短期东西向移动有趋“冷”的趋势,即西太副高向非绝热加热减弱或者非绝热冷却增强方向移动;在西太副高突然东退前后,东风带扰动东、西侧的非绝热加热效应出现明显的变化,主要体现为东风带扰动东侧非绝热冷却效应增强和东风带扰动西侧非绝热冷却效应减弱东退的特征,而且在对流层300 hPa高度附近表现最为明显;在非绝热加热效应影响因子中,垂直输送项最为重要,其次为局地变化项,水平平流效应最不显著,因此,垂直输送作用和局地变化作用引起的非绝热效应的变化是影响西太副高突然东退的主要原因。      

北京市大兴区大气降尘环境磁学特征及其环境意义

应用环境磁学方法对北京市大兴区大气降尘环境磁学特征进行了系统研究,并通过与北京市朝阳区、兰州市大气降尘环境磁学特征的对比,对环境磁学在污染物来源解析及扩散条件研究中的应用机理进行了探讨。结果表明,大兴区大气降尘磁性矿物含量明显高于本区表土,人为源影响显著;降尘样品磁学特征主要受磁铁矿控制,并含有一定数量的磁赤铁矿,磁性矿物为准单畴和多畴颗粒;大兴区降尘样品的磁性矿物含量明显低于朝阳区,且样品颗粒相对较细,表明人口密度、车流量、城市发达度对大气污染程度存在显著影响;大兴区与兰州市大气降尘磁性矿物含量的季节变化差异表明,燃煤取暖对北京大气质量的影响显著减弱,燃煤锅炉改造是大气污染防治的重要措施之一。气象因素对大气颗粒物浓度变化有重要影响,降水、低气压和高风速利于大气颗粒物的清除和扩散,低气温对大气颗粒物污染的负面影响显著。     

An inter-laboratory comparison of cosmogenic 3He and radiogenic 4He in the CRONUS-P pyroxene standard

This study reports an inter-laboratory comparison of the ³He and ⁴He concentrations measured in the pyroxene material CRONUS-P. This forms part of the CRONUS-Earth and CRONUS-EU programs, which also produced a series of natural reference materials for in situ produced ²⁶Al, ¹⁰Be, ¹⁴C, ²¹Ne and ³⁶Cl.Six laboratories (GFZ Potsdam, Caltech Pasadena, CRPG Nancy, SUERC Glasgow, BGC Berkeley, Lamont New York) participated in this intercomparison experiment, analyzing between 5 and 22 aliquots each. Intra-laboratory results yield ³He concentrations that are consistent with the reported analytical uncertainties, which suggests that ³He is homogeneous within CRONUS-P. The inter-laboratory dataset (66 determinations from the 6 different labs) is characterized by a global weighted mean of (5.02 ± 0.12) × 10⁹ at g⁻¹ with an overdispersion of 5.6% (2σ). ⁴He is characterized by a larger variability than ³He, and by an inter-lab global weighted mean of (3.60 ± 0.18) × 10¹³ at g⁻¹ (2σ) with an overdispersion of 10.4% (2σ).There are, however, some systematic differences between the six laboratories. More precisely, 2 laboratories obtained mean ³He concentrations that are about 6% higher than the clustered other 4 laboratories. This systematic bias is larger than the analytical uncertainty and not related to the CRONUS-P material (see Schaefer et al., 2015). Reasons for these inter-laboratory offsets are difficult to identify but are discussed below. To improve the precision of cosmogenic ³He dating, we suggest that future studies presenting cosmogenic ³He results also report the ³He concentration measured in the CRONUS-P material in the lab(s) used in a given study.     

Elements’ Geochemical Characteristics of PM10 and PM2.5 in Beijing During Winter and Spring

From 2012 to 2013, heavy haze frequently hit Beijing in spring and winter. The fine atmospheric particulates can be inhaled by people, and remain in the respiratory tract and lung for quite a long time. The heavy metal elements in the particles are harmful, and even carcinogenic to human bodies. Therefore, it is necessary to master the geochemical characteristics and the temporal and spatial distribution of the heavy metal elements in atmospheric particles. The atmospheric particulates (TSP/PM₁₀/PM_2.5) were collected by using TH1500C intelligent medium volume (80~120 L/min) air samplers in the five functional areas and suburbs of Beijing, respectively in January 2013 (heating period) and April 2013 (non-heating period). The five functional areas were: building materials factory area, residential area, education area, business area and recreation area, each functional area having three sampling sites, and five in suburbs. The sampling height was 1.5 m above the ground and the distance of the sampling sites to roads exceeded 50 m so as to avoid excessive impact of vehicle exhaust emissions. These samples were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), Inductively Coupled Plasma Optical Emission Spectrometer(ICP-OES)and Atomic Fluorescence Spectrometer (AFS), by which 21 elements including Al, Fe, Mn, As, Hg, Cd, Cr were tested. Based on the comparisons of the concentration and element content variation of atmospheric particulates of these functional areas in and after the heating period, the spatial distribution of atmospheric particulates and the influence of coal combustion on the concentration and composition of atmospheric particulates were revealed. The elements sources of atmospheric particulates were also discussed by computing the enrichment factor of the elements, providing a scientific basis for the air contaminant treatment in Beijing. The results showed that the total concentration of the 21 elements of PM₁₀ and PM_2.5 in the functional areas of Beijing in winter was higher than that in spring, the most marked among them being the business area. In winter, the concentration of pollution elements in the building materials factory area and the business area in Beijing was extremely high, and the residential area, education area, recreation area and suburbs where people live were much better, among which the education area was the best. The concentration change of particulates in suburbs was quite smaller in winter and spring than that of the urban area. It also showed that the concentrations of Cd, Cr, As and Hg in PM₁₀ increased by 233%,306%,298%,141%,respectively and the increase in PM_2.5 was 442%、309%、310%、256%, respectively. These abovementioned elements show a tendency to accumulate mainly in PM_2.5 whose concentrations in winter were significantly higher than those in spring. It indicates that coal heating during winter makes great contributions to the polluting elements in atmosphere and the main polluting particulates are Cd, As and Hg.