Seasonal Dynamics in Dissolved Organic Carbon Concentrations in a Coastal Water-Table Aquifer at the Forest-Marsh Interface

The seasonal dynamics of dissolved organic carbon (DOC) in a subterranean estuary were examined in a coastal water-table aquifer extending across a forest-marsh interface into an adjacent tidal creek that leads to North Inlet (SC). The aquifer is characterized by groundwater flow from the forest recharge area towards the creek. DOC concentrations range from 50 to 140 mg L^-1 in the shallow portions of the aquifer below the forest and undergo seasonal changes that are inversely related to temperature and precipitation conditions. Markedly lower DOC concentrations (<10 mg L^-1) in the deep portion of the aquifer are consistent with the loss of a large fraction of the original DOC along the groundwater flow paths. Mass balance estimates indicate that over 60% of the DOC losses are due to sorption reactions whereas the rest appear to be caused by heterotrophic decay. Groundwater DOC discharge from the forest, which occurs in a restricted zone of the high marsh, is 5.5 mg carbon m^-2 d^-1 and accounts for a minor component of the annual carbon export from North Inlet. In contrast, moderately saline (2–12 ppt) ground waters below the marsh display elevated DOC concentrations (20 mg L^-1) that appear to be the result of mixing of fresh ground waters and surface seawater during tidal seepage and concentration during evapotranspiration. The flux of DOC associated with the discharge of these saline ground waters is 600 mg carbon m^-2 d^-1, which represents a significant fraction of the annual DOC budget for North Inlet.     

Stability of the Triangular Libration Points in the Unrestricted Planar Problem of a Symmetric Rigid Body and a Point Mass

In papers (Godziewski and Maciejewski, 1998a, b, 1999), we investigate unrestricted, planar problem of a dynamically symmetric rigid body and a sphere. Following the original statement of the problem by Kokoriev and Kirpichnikov (1988), we assume that the potential of the rigid body is approximated by the gravitational field of a dumb-bell. The model is described in terms of a 2D Hamiltonian depending on three parameters.In this paper, we investigate the stability of triangular equilibria permissible by the dynamics of the model, under the assumption of low-order resonances. We analyze all resonances of order smaller than four, and we examine the stability with application of theorems by Markeev and Sokolsky. These are the possible following cases: the non-diagonal resonance of the first order with two null characteristic frequencies (unstable); resonances of the first order with one nonzero frequency (diagonal and non-diagonal, stable and unstable); the second-order resonance, which is non-diagonal and stable, and the third-order resonance which is generically unstable, except for three points in the parameters' space, corresponding to stable equilibria.We discuss a perturbed version of Kokoriev and Kirpichnikov model, and we find that if the perturbation is small and depends on the coordinates only, the triangular equilibria persist, except if for the unperturbed equilibria the first-order resonance occurs. We show that the resonances of the order higher than two are also preserved if the perturbation acts.     

35Ma地质历史上一个重要的自然周期

在地球发展过程中存在着３５Ｍａ的旋回周期，它不仅表现在全球性海平面变化、生物集群绝灭、构造运动幕、岩浆旋回以及石气候变化方面，而且也反映在古地磁倒转和陨击事件方面，反映了地球演化的自然阶段．重要地质事件明显地集中于特定时期，形成自然临界，其可能主要受天体运动周期的控制，与太阳系穿越银道面有关     

基于状态和残差的北斗基准站观测数据表达与信息分级

北斗卫星导航系统基准站通常直接存储传输原始观测量,导致了两种不利情况：①没有形成对用户的分级授权机制,任意用户通过原始观测量都可以获取基准站的精确空间基准、时间基准和大气基准数据,这会对基准站的安全构成潜在威胁;②原始观测量之间的强相关性导致其数据量很大,在北斗接收机观测显现网络化、不间断、高采样和多波段的趋势下,观测数据的海量爆发给数据的存储和传输都带来了巨大的压力。因此,本文提出利用状态和残差来表达北斗基准站观测数据。与通用的基于RINEX、Compact RINEX和RTCM等国际协议的数据服务相比,其优点是不但可以对不同级别用户进行信息分级授权,从技术上保障数据服务的安全,而且大幅减小了存储传输数据量和用户端计算量。同时本文证明了新的表达方式与原始数据等效,不会降低最终计算结果的精度。利用该方法可以建立具有自主知识产权的北斗观测数据存储和传输协议,并为高精度星基数据播发服务提供技术支持。     

Synchroneity between marine and terrestrial responses to millennial scale climatic variability during the last glacial period in the Mediterranean region

Land-sea climatic proxies have been obtained from the Last Glacial section of IMAGES core MD95-2043 (western Mediterranean Sea). Vegetation and alkenone derived SST curves indicate rapid (~150 years) and synchronous terrestrial and marine climatic changes, paralleling the Dansgaard-Oeschger (D-O) climatic variability over Greenland. This frequency of climate change can be related to shifts between the two modes of operation of the North Atlantic Oscillation (NAO). Transfer functions applied to the pollen data indicate that there was an amplification of the climatic signal during Heinrich events (HEs) in comparison with other D-O stadials. The development and persistence of both Scandinavian and Atlantic Mobile Polar Highs over southwestern Europe may explain the extreme cooling (~10 °C) and dryness (400 mm) during Heinrich events 5 and 4 in the Mediterranean region. Comparison of the results of core MD95-2043 with similar climatic data from IMAGES core MD95-2042, located off Portugal, indicates that thermal and precipitation gradients occurred between the Mediterranean and the Atlantic sides of Iberia within HEs. HEs 4 and 5 are associated with more humid conditions in the Atlantic (by 200 mm) than in the Mediterranean site, as is the case at the present time. This comparison also illustrates the different behaviour of these areas during the D-O stadials. In contrast with the Mediterranean site, the Atlantic site shows similar precipitation and temperature drops for all the D-O stadials, including those related to the HEs. Here we propose the operation of different Mobile Polar Highs (MPH) as the driving mechanism for this difference in behaviour between the Atlantic and Mediterranean sides of Iberia. HEs are related to a stronger influence of the Scandinavian MPH, forcing a severe aridification and cooling of the full Iberian Peninsula. The Atlantic MPH may have been dominant during the other stadials, which would preferentially affect Southwestern Iberia.     

Dryness-wetness change and regional differentiation of flood-drought disasters in Guangdong during 1480-1940AD

Based on the historical records of the drought and flood disasters during 1480-1940AD, this paper reconstructs the sequences of wetness index (WI) and drought and flood disasters. We find a good identical relationship between the fluctuation of WI sequence and the δ18O record of the GISP2 ice core in Greenland, which shows an apparent monsoonal disposal pattern of moisture and temperature. By applying the Morlet Wavelet Transform Method to deal with the data, several apparent periodicities, such as 7-8a, 11-15a, 20-23a and ca 50a, are revealed, among which some can be attributed to the solar forcing. Based on results of Cluster Analysis of dry-wet changes, we resume the regional differentiation pattern of flood-drought disasters all over Guangdong during different climatic intervals in the LIA and, find the western and northern parts of Guangdong have undergone drastic changes in drought-flood regional differentiation, but the eastern part is relatively stable, and the area of the Pearl River Delta shows stable condition of more flood disasters.     

近40a江苏省夏季旱涝的演变、分型及特征分析

通过1961～2000年江苏省13个站点夏季降水量场时间序列的EOF分析，探讨江苏省夏季旱涝异常的演变特征，根据第一、二特征向量分型，可将江苏省旱涝分成旱型、涝型、南旱北涝和南涝北旱四种主要空间型。并在此基础上利用合成分析，对其前期及同期500hPa、100hPa高度距平场的特征进行分析，发现各型前期和同期有不同的大气环流特征，得到了一些对本地夏季降水量有预测意义的结果。     

利用WORD模板功能快速实现成果地质资料文字部分的制作

利用word提供的模板功能可以设置符合规范要求的地质资料电子文档.依据地质资料排版格式,在充分考虑报告名称、类别、字体、章节标题、图表以及各种必要的附加项目的基础上,制作出规范的电子文档模板,然后根据模板提示录入相关内容.     

青藏高原地区FGGEⅢb资料相对湿度场的分析与订正及其对预报影响的数值试验

本文用Ｃｒｅｓｍａｎ逐步订正法和青藏高原气象科学实验资料对高原地区１９７９年６—８月中６０个时次的ＦＧＧＥⅢｂ级资料相对湿度场进行了订正和分析，然后利用一有限区域数值模式，选择两例高原低涡过程，用订正前后的ＦＧＧＥⅢｂ相对湿度资料分别作初始湿度场进行了７２ｈ和４８ｈ预报试验。结果表明：高原地区相对湿度的高值区位于其东南部，然后向西北逐渐递减，低值区位于高原西部。ＦＧＧＥⅢｂ相对湿度场能较好地反映高原东部的分布，但在高原西部比实际明显偏大。订正高原上的初始湿度场（ＦＧＧＥⅢｂ相对湿度场）能明显改进高原地区的降水和形势预报，对环流的影响可达到高原东侧并波及高原的南北侧地区，显示了加密高原西部资料的重要性。     

Heavy metals in sediments as evidence for recent pollution and quasi-estuarine processes: an example from Lake Druzno,Poland

This article presents the results of a geochemical investigation of sediments from Lake Druzno (northern Poland), a reservoir fed by freshwater from the catchment, with periodic input of brackish water from Vistula Lagoon. This study analyzed the spatial variation in heavy metal content in surface sediments as well as the temporal changes in metal content in two sediment cores dated using the ²¹⁰Pb method. In the surface sediments, the highest metal concentrations were recorded in the northern part of the lake, with lower concentrations in the central and southern parts. Absolute values of metal concentrations in the cores were low, but normalization with respect to Al showed an increase during the second half of the 20th century. Mean enrichment factors (EF) in sediments from the second half of the 20th century ranged from insignificant (1–1.2) for Fe to (1.55–3.3) for Cu, Cd, Pb and Zn. The sediments deposited before 1950 had lower EF values (>1.5) and had low variability. Results from both the surface sediments and the cores indicate that the main source of lake pollution is brackish water intrusion from the Vistula Lagoon via the contaminated River Elbląg.