重庆雾和霾的气候特征分析

利用1981—2014年重庆地区气象观测资料,基于气候统计法分析重庆地区雾和霾的气候特征,结果表明:重庆雾日总体呈显著减少趋势,两种雾日观测资料的倾向率分别为为-10.3 d/10a和-7.6 d/10 a;雾日的空间分布总体呈"中西部多,东南东北少,西部偏北地区多于西部偏南地区"。霾日总体趋势与雾日变化相反,呈显著上升趋势,倾向率为12.9 d/10a,并且霾日发生显著增加的时段与雾日发生显著减少的时段基本一致,2000年前后霾日经历了明显的突变;霾的分布主要呈现"以主城为中心,中西部多,东北部和东南部少"的特点。     

中国黄渤海沉积物声速与物理性质研究

In order to investigate the correlation between a sound velocity and sediment bulk properties and explore the influence of frequency dependence of the sound velocity on the prediction of the sediment properties by the sound velocity,a compressional wave velocity is measured at frequencies of 25–250 k Hz on marine sediment samples collected from the Bohai Sea and the Yellow Sea in laboratory,together with the geotechnical parameters of sediments.The results indicate that the sound velocity ranges from 1.232 to 1.721 km/s for the collected sediment samples with a significant dispersion within the series measuring frequency.Poorly sorted sediments are highly dispersive nearly with a positive linear relationship.The porosity shows a better negative logarithmic correlation with the sound velocity compared with other geotechnical parameters.Generally,the sound velocity increases with the increasing of the average particle size,sand content,wet and dry bulk densities,and decreasing of the clay content,and water content.An important point should be demonstrated that the higher correlation can be obtained when the measuring frequency is low within the frequency ranges from 25 to 250 k Hz since the inhomogeneity of sediment properties has a more remarkably influence on the laboratory sound velocity measurement at the high frequency.     

Earth observation metadata ontology model for spatiotemporal-spectral semantic-enhanced satellite observation discovery: a case study of soil moisture monitoring

Monitoring soil moisture with satellite sensors is an effective approach for agricultural drought assessment. Currently, large quantities of sensor-derived observation data with different observation metadata models exist, and they require efficient and accurate methods of discovery. In this study, an earth observation (EO) metadata ontology with a spatiotemporal-spectral-enhanced structure is designed to solve this problem. The ontology is based on the proposed EO metadata model, which is composed of nonfunctional and functional sub-modules and supports the Open Geospatial Consortium EO profile of observations and measurements. Using EO metadata ontology, an application for soil moisture monitoring in Hubei Province in China is tested. The results indicate that metadata retrieval with a spatiotemporal-spectral-enhanced method can efficiently achieve fine-grained discovery of qualified EO metadata and obtain soil moisture monitoring information from sensor images. In summary, the spatiotemporal-spectral semantics in the proposed ontology demonstrate the use of EO metadata in the context of a soil moisture monitoring application, improving the efficiency and accuracy of EO metadata discovery.     

Liquid water path retrieval using the lowest frequency channels of <Emphasis Type="Italic">Fengyun-3C</Emphasis> Microwave Radiation Imager (MWRI)

The Microwave Radiation Imager (MWRI) on board Chinese Fengyun-3 (FY-3) satellites provides measurements at 10.65, 18.7, 23.8, 36.5, and 89.0 GHz with both horizontal and vertical polarization channels. Brightness temperature measurements of those channels with their central frequencies higher than 19 GHz from satellite-based microwave imager radiometers had traditionally been used to retrieve cloud liquid water path (LWP) over ocean. The results show that the lowest frequency channels are the most appropriate for retrieving LWP when its values are large. Therefore, a modified LWP retrieval algorithm is developed for retrieving LWP of different magnitudes involving not only the high frequency channels but also the lowest frequency channels of FY-3 MWRI. The theoretical estimates of the LWP retrieval errors are between 0.11 and 0.06 mm for 10.65- and 18.7-GHz channels and between 0.02 and 0.04 mm for 36.5- and 89.0-GHz channels. It is also shown that the brightness temperature observations at 10.65 GHz can be utilized to better retrieve the LWP greater than 3 mm in the eyewall region of Super Typhoon Neoguri (2014). The spiral structure of clouds within and around Typhoon Neoguri can be well captured by combining the LWP retrievals from different frequency channels.     

南海曾母盆地新生代晚期构造沉降分析

曾母盆地是一个ＮＷ向走滑型沉积盆地，新生代晚期经历了强烈沉降（Ｅ３－Ｎ１１）、平缓沉降（Ｎ１２－Ｎ１３）、加速沉降（Ｎ２）和差异升降（Ｑ）四个时期，其构造演化主要取决于加里曼丹与南沙两地块间的相互作用所引起的ＮＷ向断裂的活动方式．     

东帝汶海30ka以来的表层水和温跃层水温度变化及其古海洋学意义

研究了钻取于东帝汶海印尼穿越流出口处MD98-2172岩心沉积物,分析了浮游有孔虫表层水种Globigerinoides ruber和温跃层水种Pulleniatina obliquiloculata的Mg/Ca值,重建了30kaBP以来东帝汶海区的表层水温度和温跃层水温度。结果显示东帝汶海区末次冰盛期以来表层水温度距早全新世的最大温差约为4.2℃;冰消期间表层水温度有两次显著的降温事件,可分别与新仙女木事件和海因里希事件1对应;约15kaBP以来帝汶海表层水温度与南极大气温度记录同相位变化,说明热带海区与高纬度地区气候变化有着紧密联系。末次冰盛期以来温跃层水温度距早全新世的最大温差约为4℃;全新世温跃层水温度呈现出波动降低的过程,最大降温幅度约3℃;表层水温度和次表层水温度差值在全新世逐渐增加,指示了温跃层深度的持续变浅,这一变化可能与海平面上升、季风活动和厄尔尼诺-南方涛动事件影响的印度尼西亚穿越流次表层流增强有关。     

海底沉积物孔隙压力原位长期观测技术回顾和展望

海底沉积物孔隙压力对海底地质灾害过程反应敏感,是表征海床稳定性的一个重要指标,通过海底沉积物的孔隙压力观测可以判断海床的稳定状态,对于海底地质灾害预测预警具有重要意义。海底沉积物孔隙压力观测存在(1)超高背景压力下的高精度测量;(2)贯入过程传感器超量程破坏;(3)系统长期供电及传感器漂移;(4)深海海底布放和回收等技术难点。国际上海底孔隙压力观测技术从20世纪60年代开始发展,逐渐形成了系列核心监测技术和成熟的商业化设备产品。挪威岩土工程研究所NGI与美国伊利诺伊大学共同研发的NGI-Illinois压差式孔隙压力观测系统,是已知最早的海底沉积物孔隙压力观测设备。此后,美国地质调查局USGS、美国桑迪亚国家实验室、英国牛津大学等相继研发了不同结构的观测设备,覆盖浅海到深海。其中,英国海洋科学研究所研发成功的深海孔隙压力原位长期观测设备PUPPI是一个重要的历史节点,该设备能够在6 000 m水深的环境中连续运行一年,成为当时最成功的海底孔隙压力观测设备,其现代化的设备结构和设计理念被后续的观测设备广为借鉴。21世纪以来,得益于海洋科学技术的整体进步,国际孔隙压力观测技术发展呈现加速趋势。法国海洋开发研究院IFREMER研发的Piezometer系列孔隙压力观测探杆,代表了当今世界的先进水平,可能是目前应用次数最多的海底孔隙压力观测设备。我国在深海探测、观测技术领域起步较晚,在深海沉积物孔隙压力原位长期观测技术方面几乎空白,发展很不成熟。其中,中国海洋大学、自然资源部第一海洋研究所等单位进行了较多的探索性研发工作。近年来,以港珠澳大桥建设、南海天然气水合物试采等为标志的大批国家级海洋建设项目如火如荼,深海油气矿产资源开发、深海天然气水合物开采利用等海洋新兴产业快速起步,深海孔隙压力原位长期监测关键核心技术等“卡脖子”问题仍然突出,严重制约了我国海洋工程产业发展的步伐。因此,迫切需要发展具有自主知识产权和关键核心技术的国产深海沉积物孔隙压力原位长期监测技术。本文回顾了国际、国内海底孔隙压力观测技术的相关研究进展,旨在分析总结孔隙压力观测技术及其应用中涉及的一些核心技术和亟待解决的关键问题,以期为我国该项技术的发展和应用提供借鉴。     

Striping Noise Analysis and Mitigation for Microwave Temperature Sounder-2 Observations

The Microwave Temperature Sounder(MWTS)-2 has a total of 13 temperature-sounding channels with the capability of observing radiance emissions from near the surface to the stratosphere. Similar to the Advanced Technology Microwave Sounder(ATMS), striping pattern noise, primarily in the cross-track direction, exists in MWTS-2 radiance observations. In this study, an algorithm based on principal component analysis(PCA) combined with ensemble empirical mode decomposition(EEMD) is described and applied to MWTS-2 brightness temperature observations. It is arguably necessary to smooth the first three principal component(PC) coefficients by removing the first four intrinsic mode functions(IMFs) using the EEMD method(denoted as PC3/IMF4). After the PC3/IMF4 noise mitigation, the striping pattern noise is effectively removed from the brightness temperature observations. The noise level in MWTS-2 observations is significantly higher than that detected in ATMS observations. In May 2014, the scanning profile of MWTS-2 was adjusted from varying-speed scanning to constantspeed scanning. The impact on striping noise levels brought on by this scan profile change is also analyzed here. The striping noise in brightness temperature observations worsened after the profile change. Regardless of the scan profile change, the striping noise mitigation method reported in this study can more or less suppress the noise levels in MWTS-2 observations.     

露点测湿技术优势探究

湿度测量技术繁多,露点测湿技术具有较大的优势,基于露点测湿技术设计的仪器能在全量程内达到较高准确度。本文以《气象仪器观测方法指南》中公布的饱和水汽压计算公式为基础,结合误差传递理论,计算得到不同等级露/霜点温度标准不确定度下的相对湿度标准不确定度,以此探究露点测湿技术在准确度上的优势。结果表明:在-60～60℃的全温度范围内,露点仪相对湿度测量标准不确定度在低温高湿情况下较大;当环境温度和露/霜点测量标准不确定度均为0.1℃时,相对湿度测量标准不确定度最大不超过2.0%,满足《气象仪器观测方法指南》中对湿度标准器标准不确定度最低要求;当环境温度和露/霜点测量标准不确定度分别为0.3℃(0.5℃)和0.1℃时,相对湿度测量标准不确定度最大不超过4.3%(7.0%)。可见低温情况下,露点仪相对湿度测量标准不确定度优势明显。     

微生物异常探索江汉盆地江陵凹陷万城断裂带北部油气富集规律及有利区

江汉盆地江陵凹陷万城断裂带北部研究区,地表条件复杂,地震和钻井施工困难,油气富集规律还不甚清楚。因此,试图通过微生物找油方法,最小成本最高效率,以探明本研究区的油气富集规律。研究区面积约230.0 km2,采集样品间距南北500 m × 东西250 m,共采集并分析了样品2354个。研究表明,微生物异常主要分布在万城断层的东侧,其中微生物气异常零星分布,异常较弱,无独立气藏。在综合地质等资料的基础上,微生物异常分布特征表明,万城断裂带显示了来自北西和北东向的双向物源,油气来源于梅槐桥洼陷,属近源成藏。万城断裂带东侧和坡折带低位扇砂体是油气有利富集区,前景较好,主要为古近系新沟咀组成藏。万城断裂带西侧有小面积油藏,可能系白垩系成藏。最后,对微生物异常区进行了分级评价,指明了重点攻关区、评价有利和较有利区,对大幅降低勘探风险和提高勘探成功率,具有重大的社会经济效益和深远的现实意义。