数值预报产品在台风路径预报中的应用     

季晓阳 《海洋预报》1996,13(1):16-22

利用欧洲中期天气预报中心和国家海洋环境预报中心的数值预报产品，形成包括理想台风模型的模式初值，用正压原始方程做台风路径预报，经过１９９４年的６个台风的实时预报试验，效果较好。  相似文献   

Biomarkers derived from heterolytic and homolytic cleavage of allylic hydroperoxides resulting from alkenone autoxidation     

J.-F. Rontani  R. Harji  J.K. Volkman 《Marine Chemistry》2007

Laboratory incubation of alkenone mixtures with tert-butyl hydroperoxide and di-tert-butyl nitroxide (radical initiator) in hexane, as a means to simulate alkenone autoxidation processes, rapidly led to the formation of allylic hydroperoxides, whose presence was recently demonstrated in Emiliania huxleyi cells. After incubation in seawater and subsequent reduction with NaBH₄ (to reduce residual hydroperoxides before analysis), these reaction products quickly disappeared and were replaced by complex mixtures of n-alcohols, fatty acids, alkyldiols and hydroxyacids. Methyl alkenones produced saturated n-alkan-1-ols and fatty acids ranging from C₁₃ to C₁₆ and two series of C₁₃−C₁₆ (ω-1)-hydroxyacids and (1,ω-1)-diols. Ethyl alkenones also afforded C₁₃−C₁₆ saturated n-alkan-1-ols and fatty acids, accompanied by the production of C₁₄−C₁₇ (ω-2)-hydroxyacids and (1,ω-2)-diols. Deuterium labelling allowed us to show that most of the n-alkan-1-ols, hydroxyacids and alkyldiols resulted from the reduction during the NaBH₄ treatment of the corresponding aldehydes, ketoxyacids and ketoxyaldehydes formed from heterolytic or homolytic cleavages of allylic hydroperoxyl groups resulting from the oxidation of the double bonds of di- and triunsaturated alkenones. Amongst these products, the (ω-1)- and (ω-2)-hydroxyacids formed after NaBH₄ reduction of the (ω-1)- and (ω-2)-ketoxyacids were selected as potential biomarkers for alkenone autoxidation. Re-examination of lipid extracts of post-bloom seawater particulate matter samples from the DYFAMED station in the Ligurian Sea (where strong autoxidative alteration of the lipid distributions had previously been detected) showed the presence of significant amounts of 12-hydroxytetradecanoic, 13-hydroxytetradecanoic, 14-hydroxyhexadecanoic and 15-hydroxyhexadecanoic acids thus providing good evidence that these autoxidative processes occur in natural samples.  相似文献   

大到暴雪天气模型及数值产品释用预报方法     

Chang Jun  Li Zhen  BuYalin  Li Suping  Liu Sha 《河南气象》2007,(3)

用欧洲数值预报产品格点资料,对1986年11月-2002年3月河南省出现的87个大到暴雪个例进行对比分析,将大到暴雪划分为3个类型,即高原低槽型、阻高-横槽型和L型,对每个型进行合成平均,建立了大到暴雪的天气学概念模型。为提高样本中大到暴雪的概率,先将样本进行消空处理,然后选取物理意义清晰、天气学意义明确的预报因子,分别建立了全省分片大到暴雪1-7 d预报方法,在业务试应用中取得了较好的预报效果。  相似文献   

Lignin degradation products as palaeoenvironmental proxies in the sediments of small lakes     

Karol Kuliński  Joanna Święta-Musznicka  Andrzej Staniszewski  Janusz Pempkowiak  Małgorzata Latałowa 《Journal of Paleolimnology》2007,38(4):555-567

The quantity and quality of lignin phenols (Σ8, Λ, S/V, C/V and (Ad/Al)_v) in the sediments of three small Lobelia lakes with neither inlets nor outlets were investigated and compared with palynological data and lithology of the profiles. The method of alkaline CuO oxidation was used. Substantial differences with respect to sedimentary lignin concentration and provenance recorded along the profiles and among the sites are in good agreement with pollen data describing the dominant type of vegetation and with indices of soil erosion in the lakes’ catchments. This relation shows that the compositions of lignin degradation products in these lakes are closely related to the local environmental conditions. In all the lakes gymnosperm wood is the main source of lignin products; however, each lake is characterized by different S/V index values. Especially good correlations were obtained between pine pollen proportions in sediments and the S/V index. The correlation between the C/V and (Ad/Al)_v indices indicates a higher degradation of organic matter when non-woody tissue is more abundant. This pilot study illustrates the usefulness and potential for a wider application of lignin oxidation products in palaeoecological reconstructions. This kind of data would be of special importance when investigating local presence/absence of woody plants and the role of angiosperms/gymnosperms in local vegetation. Estimates of lignin biodegradation levels, as well as the data on diagenetic processes, may afford supplementary information on possible disturbances in sedimentation.  相似文献   

山东省新一代天气雷达组网业务应用     

王建国  高玉春  朱君鉴  黄磊  罗慧敏  刁秀广 《气象》2006,32(10):102-106

为挖掘雷达应用潜力、充分发挥雷达的整体建设效益，山东省气象局进行了雷达产品的实时拼图和实时远程调用研发工作。通过宽带网实时收集、存贮雷达产品，增置省级雷达产品服务器、建立辅PUP，实现了山东全省5部新一代天气雷达及邻省周边雷达每6分钟一次实时拼图产品和雷达产品远程调用。对于省级气象台所关注的范围，拼图产品能有效地监测预警辖区内各种尺度天气系统的移动和演变；对于局地性强的中小尺度对流天气，雷达产品远程调用能实现CINRAD／SA雷达PUP上的重定中心、局部放大、动画显示、光标联接、地图和产品叠加等功能，对于远距离下级台站的精细预报的指导是十分有用并且可行的。从国家信息中心获取周边邻近雷达的产品信息，对于及时了解上游及周边天气情况非常有用。  相似文献   

Geochemical Changes in Spring Water Associated with the 2000 Eruption of the Miyakejima Volcano, Japan     

Tsutomu Sato  Isao Machida  Makoto Takahashi  Taro Nakamura 《Pure and Applied Geophysics》2006,163(4):809-823

Water was sampled from eight springs and a lake in volcanic Miyakejima Island of Japan after the 2000 eruption. Major chemical and isotopic compositions of the water were analyzed. Significant increases of sulfate ion are observed in several springs where the thickness of ejecta exceeds 32 mm. A good relationship of Cl/S mole ratios between spring water and leachate of the ejecta is observed. Sulfur isotopic compositions of the spring water become close to that of leachate of the ejecta as time elapses after the eruption. Consequently the sources of the added sulfate ion in the spring water after the eruption are interpreted to be anhydrite and adhered sulfur of the ejecta.  相似文献   

巴州地区一次大降水过程的分析     

张鄞 《沙漠与绿洲气象(新疆气象)》2003,26(3):8-10

对2002年6月16～18日、21日巴州地区出现的大范围的降水天气过程，重点从环流形势、物理量场以及数值预报产品的应用等方面作了初步分析，得出了一些有益的结论。  相似文献   

Primary Product Distribution from the Reaction of Hydroxyl Radicals with Toluene at ppb NOX Mixing Ratios     

D. F. Smith  C. D. McIver  T. E. Kleindienst 《Journal of Atmospheric Chemistry》1998,30(2):209-228

A study has been conducted to examine the OH-initiated degradation products of toluene in the presence of sub part-per-million levels of NO_X. The experiments were conducted in a dynamic reactor to minimize the conversion of the aromatic compounds while allowing a sufficient mass of products to be collected for analysis. The major primary products detected in the toluene system (with molar yields) include glyoxal (0.238), methylglyoxal (0.167), o-cresol (0.120), benzaldehyde (0.06), 4-oxo-2-pentenal (0.03), and p-cresol (0.03). Six other reaction products, most being ring cleavage products, were measured at yields below 3%. Corrections for secondary OH reactions with the products were made where necessary. The formation of the cresol isomers was found to be invariant to the NO₂ concentrations which indicates that under atmospheric conditions the initial hydroxycyclohexadienyl radical reaction with NO₂ is a minor process and that most of the reaction occurs with O₂. The product yields found in this study are expected to be representative of those that occur in the urban atmosphere at ambient NO₂ concentrations.  相似文献   

Using Chlorine Dioxide for Drinking Water Disinfection by the Application of the Chlorite/Chlorine Process     

Wido Schmidt 《洁净——土壤、空气、水》2004,32(1):48-60

Chlorine dioxide stock solutions for the disinfection of drinking water are made by the application of chlorite/chlorine process in many waterworks. In such cases the stock solution is always characterised by a mixture of chlorine and chlorine dioxide. The disinfection of waters of different origin with a mixture of chlorine dioxide and chlorine showed the formation of odours of different intensity. The reasons are the re‐formation of chlorine dioxide and the formation of odorous disinfection by‐products. Applying the chlorine dioxide for disinfection, its re‐formation caused by the reaction of chlorite with chlorine is the dominant reason of odour formation. When chlorine is used, the formation of odorous by‐products becomes more relevant. In order to quantify the sensitivity of water concerning odour, the odour indicator coefficient OI was defined. The decreased demand of chlorine dioxide by applying chlorine and chlorine dioxide in combination is recognised to be the key in order to avoid the formation of odour after the disinfection of drinking water with chlorine dioxide.  相似文献   

完全预报（PP）方法在广东冬半年海面强风业务预报中的应用   总被引：1，自引：2，他引：1       下载免费PDF全文

林良勋  程正泉张兵　胡斯团 《应用气象学报》2004,15(4):485-493

在进行大量普查分析和统计的基础上, 将最近10年历史天气图的地面气压和有关海面强风代表站的风场资料在日本数值预报模式输出报文的1.25°×1.25°格点分布上进行客观分析, 对比传统的以关键区域划分冷空气入侵路径与广东海面强风的关系, 提出了一套与广东冬季海面强风关系更密切、作用更直接的地面关键区气压场分布特征进行客观定量的分型;根据梯度风原理, 用经验加统计的因子挑选方法, 形成了一套应用日本数值预报模式输出、适用于广东海面强风预报的完全预报(PP)方法。检验和业务试用结果均表明:该方法对广东的海面强风具有较强的预报能力;用完全预报方法做沿海海面强风预报是可行的。  相似文献