GPM卫星反演降水产品在江苏地区的适用性

以江苏省70个地面雨量站分钟观测数据为基准,对比分析了一个完整年周期GPM卫星搭载的双频降水雷达(DPR)反演降水产品精度。结果表明DPR常规模式(NS)、匹配模式(MS)和高灵敏度模式(HS)扫描产品反演降水与地面雨量计观测数据均在过境后几分钟内达到最佳匹配效果。以NS产品为例,全年反演降水均方根误差大致为2mm/h,相关系数在0.5以上,相对偏差为-20%左右。并且降水产品在夏季反演精度最高。对反演误差进行初步分析发现,卫星反演降水率算法精度对校正因子ε有非常强的敏感性,并且选择ε值的算法约束不足会导致最终计算求解模块SLV的路径积分衰减PIA值异常,引起极端降水反演的误差。     

ENSO and Sea Surface Temperature Anomalies in Association with Canadian Wheat Yield Variability

Interannual variations of spring wheat yields in Canadian agricultural regions are analyzed, together with the associated sea surface temperature (SST) anomalies in the northern hemisphere tropics and extratropics, from 1961 to 2015. The cubic trend is calculated and used to represent the trend related to advances in agricultural technology over this time period. The correlations between Canadian wheat yields at regional scales and the tropical El Niño–Southern Oscillation (ENSO) variability are not robust at any stage of the evolution of ENSO. Based on the power spectrum and cross-spectrum analysis, the most prominent yield variance is found in the Canadian Prairies, with a significant power peak of 4.5 years but does not co-vary significantly with interannual ENSO variability. ENSO weakly affects temperature and precipitation anomalies in the Canadian Prairie Region in summer—two important agroclimatic conditions for crop growth—and hence insignificantly impacts wheat yields. This indicates that there would be little benefit to including tropical ENSO indices in the operational wheat yield forecasting system. For Canadian wheat yield forecasting, attention should be paid to the preceding winter and spring SST anomalies in the northern extratropics. The SST anomalies associated with yields in the Canadian Prairie region and Central Region are generally stronger than those associated with yields in the Canadian Pacific Coast Region and eastern Maritime Region. In association with the Prairie Region and Central Region yields, SST shows pronounced anomalies in the mid-high latitudes of the North Pacific from winter to summer. The non-linearity of the SST anomalies associated with the Canadian yields is also clearly evident. Stronger (weaker) SST anomalies in the extratropical North Pacific correspond to low wheat yields in the Prairie (Central) Region, while weaker (stronger) SST anomalies correspond to high yields in the Prairie (Central) Region.     

An Overview of Surface-Based Precipitation Observations at Environment and Climate Change Canada

The objective of this paper is to provide an overview of the present status and procedures related to surface precipitation observations at Environment and Climate Change Canada (ECCC). This work was done to support the ongoing renewal of observation systems and networks at the Meteorological Service of Canada. The paper focusses on selected parameters, namely, accumulated precipitation, precipitation intensity, precipitation type, rainfall, snowfall, and radar reflectivity. Application-specific user needs and requirements are defined and captured by World Meteorological Organization (WMO) Expert Teams at the international level by Observing Systems Capability Analysis and Review (OSCAR) and WMO Integrated Global Observing System (WIGOS), and by ECCC user engagement initiatives within the Canadian context. The precipitation-related networks of ECCC are separated into those containing automatic instruments, those with human (manual) observers, and the radar network. The unique characteristics and data flow for each of these networks, the instrument and installation characteristics, processing steps, and limitations from observation to data distribution and storage are provided. A summary of precipitation instrument-dependent algorithms that are used in ECCC's Data Management System is provided. One outcome of the analysis is the identification of gaps in spatial coverage and data quality that are required to meet user needs. Increased availability of data, including from long-serving manual sites, and an increase in the availability of precipitation type and snowfall amount are identified as improvements that would benefit many users. Other recognized improvements for in situ networks include standardized network procedures, instrument performance adjustments, and improved and sustained access to data and metadata from internal and external networks. Specific to radar, a number of items are recognized that can improve quantitative precipitation estimates. Increased coverage for the radar network and improved methods for assessing and portraying radar data quality would benefit precipitation users.     

冬季北太平洋大气低频环流的年际和年代际变化特征及其与大气环流和海温异常的联系

利用1979—2015年ECMWF逐日再分析资料,通过EOF分解和回归分析研究了冬季北太平洋大气低频环流的年际和年代际变化特征及其与海表面温度异常(SSTA)和大气环流异常之间的联系。研究结果表明:冬季中纬度北太平洋地区850 h Pa低频尺度环流存在3个明显的变化模态:第一模态为海盆尺度的单极型异常气旋(反气旋)式环流,同期太平洋SSTA呈现El Ni1o(La Ni1a)以及PDO暖位相(冷位相)空间分布,阿留申低压强度增强(减弱),对流层中高层是正位相(负位相)的PNA型遥相关,北太平洋天气尺度风暴轴中东部南压(北抬);第二模态为在白令海峡和副热带地区呈气旋式与反气旋式环流南北向偶极型变化,同时中纬度北太平洋SSTA呈现NPGO(North Pacific Gyre Oscillation)正位相(负位相)的空间分布,黑潮区域SSTA偏暖(偏冷),北太平洋SSTA经向梯度加大(减小),对流层中高层为负位相(正位相)的WP型遥相关,北太平洋天气尺度风暴轴整体偏北(偏南),强度增强(减弱);第三模态为北太平洋中西部和北美西岸呈气旋式与反气旋式环流东西向偶极型异常,黑潮区域SSTA偏冷(偏暖)而北太平洋东部SSTA偏暖(偏冷),SSTA纬向梯度加大(减弱),同时赤道东太平洋出现类似La Ni1a(El Ni1o)的SSTA分布,北太平洋天气尺度风暴轴中东部明显减弱(加强)而西部略有加强(减弱)。     

Impact of Perturbation Schemes on the Ensemble Prediction in a Coupled Lorenz Model

Based on a simple coupled Lorenz model, we investigate how to assess a suitable initial perturbation scheme for ensemble forecasting in a multiscale system involving slow dynamics and fast dynamics. Four initial perturbation approaches are used in the ensemble forecasting experiments: the random perturbation(RP), the bred vector(BV), the ensemble transform Kalman filter(ETKF), and the nonlinear local Lyapunov vector(NLLV) methods. Results show that,regardless of the method used, the ensemble ave...     

Evolution of Palaeoenvironment of the South Yellow Sea Since the Last Deglaciation

The sediments in core YS01 recovered from the South Yellow Sea mud deposit zone contain abundant benthic foraminifera, particularly shallow continental shelf species, but rare of planktonic foraminifera. The benthic foraminifera are dominated by stenohaline cold shallow-water species and euryhaline brackish-water species. In this paper, the palaeoenvironmental changes were discussed based on the grain-size compositions and benthic foraminiferal assemblages. Six different benthic foraminiferal assemblages were discriminated by species analysis from the foraminiferal fauna. According to AMS~(14)C dating data in core YS01, we identified four main stages of marine environmental changes since the last deglaciation: a near-shore depositional stage(13.1 – 9.5 kyr B.P.), a transitional stage from near-shore deposition to shallow-sea deposition(9.5 – 5.6 kyr B.P.), a high sea level stage with shallow-sea deposition(5.6–2.9 kyr B.P.), and a stable shallow-sea depositional stage(2.9 kyr B.P. to the present).     

工程物探在广西某重点工程勘察中的应用

中石油在西南的某重点工程项目,发现有F7断层穿过场地,为此利用浅层地震反射波法和高密度电法进行断裂带勘察。其中布设地震测线3条,电法测线4条。经勘探查明了该工程区域内的地层特征及F7断裂的位置、深度、倾向及伸深方向。根据勘探结果,在地震L1测线与高密度电法G2测线上布设钻孔验证,其结果证实,在解释的破碎带两侧地层层序正常,而破碎带内的钻孔显示有断层存在。本次勘探对F7断裂带的位置及产状的准确描述,为该重点工程的设计提供了可靠的依据。     

烃源岩评价分析项目的优化组合

在我国石油天然气行业中,对烃源岩评价的实验分析技术已形成一套比较成熟的方法,其中大部分已制订成国家标准或行业标准。但是在实际过程中,或者是全面测试,以致浪费大、收益小,或者是为过度节约而少测样品,造成信息严重丢失。为了分析测试能既节约成本又成果优秀,对各分析项目依据其有效性和局限性,分为基本项目、选择项目和补充项目三大类。针对不同的研究目的,分别提出了烃源岩样品快速筛选分析、烃源岩系统评价分析、下古生界海相烃源岩研究分析等相关实验测试分析项目的优化组合设计方案。     

Seamount volcanism associated with the Xigaze ophiolite, Southern Tibet

Basaltic lavas at Renbu, Southern Tibet are associated with the Xigaze ophiolite in the Yarlung-Zangbo suture zone. They are alkaline lavas rich in large ion lithophile elements (LILE, Ba, Rb and Sr) and high field strength elements (HFSE, Nb, Ta, Zr and Hf), but poor in Cr, Co and Ni. All of the rocks have chondrite-normalized REE patterns enriched in light rare earth elements (LREE), comparable to modern basalts of the Society Islands, Kerguelen Plateau and Broken Ridge. Abundances of some immobile or moderately immobile elements (Nb, Ta, Zr, Hf, Y, Ti and REE) are also comparable to Kerguelen alkaline basalts. The Renbu basalts are geochemically similar to oceanic island basalts (OIB) and have some elemental ratios, such as Nb/Ta ratios = 15.7–18.1, Th/Nb =  0.06–0.10, La/Nb = 0.59–0.83 and Th/Ta = 1.03–1.52, similar to the primitive mantle. Their ⁸⁷Sr/⁸⁶Sr ratios (0.70453–0.70602) are relatively high, similar to OIB. In the ⁸⁷Sr/⁸⁶Sr vs. εNd(t) diagram, the Renbu basalts plot along a trend from N-MORB to EMII (enriched mantle II), suggesting the involvement of at least two mantle sources in their generation. The Renbu basalts represent seamount volcanism associated with the Xigaze ophiolite. They formed from an OIB-type mantle source within the Neo-Tethyan Ocean that had a composition similar to the modern Indian Ocean mantle.     

化学物相法测定矿石中红柱石的含量

用快速简便的标准加入无火焰原子吸收光谱法测定人血和动物血中有害元素铅和镉。与普通的标准加入法相比,此法在样品前处理、标准曲线绘制及样品结果计算上都有了很大的简化。方法检出限为铅2.00μg/L,镉0.30μg/L;回收率为铅99.5%~101.2%,镉99.7%~101.3%;精密度为铅0.95%,镉2.18%。方法灵敏度高,精密度好,适用于特定人群血液中铅和镉含量的普查。