Circulation Around Luzon Strait in September as Inferred from CTD,Argos and Argo Measurements and a Generalized Topography-Following Ocean Model

The hydrography, wind, Argos and Argo measurements in the areas surrounding Luzon Strait were collected. Based on the hydrographic data obtained during September 1994, the improved Princeton Ocean Model using a generalized topography-following coordinate system together with a modified inverse method was applied to study the circulation in September. Observations and the diagnostic simulation produce a consistent circulation pattern, and the main dynamical features can be summarized as follows. (1) The Kuroshio has two branches with the main Kuroshio existing above 800 m depth and the western part existing above 400 m depth. The western branch of the Kuroshio leaves the main current near 20.5°N, then flows northwestward through Luzon Strait and finally flows out of the northern boundary southwest of Taiwan, consistent with the trajectory of Argos drifters. (2) The non-linear term is important and cannot be neglected in the momentum equations in the northern part of Luzon Strait under the baroclinicity field. Using non-linear dynamics, the westward intrusion of the Kuroshio into the northern part of Luzon Strait is more curved than when using linear dynamics. However, the non-linear term is smaller and so negligible around Luzon Strait under the homogeneous density field. (3) In the area from 117°E to 119°E and from 20.2°N to 21.7°N, an anticyclonic eddy appears east of Dongsha Islands. (4) At depths above 400 m, the circulation is mainly dominated by the basin-scale cyclonic gyre. (5) In the computational domain west of 121°E, the circulation below 800 m is mainly dominated by the basin-scale anticyclonic gyre. (6) The South China Sea water flows eastward across Luzon Strait in the middle layers, then turns cyclonically, finally flowing northward into the region east of Taiwan Island, which is qualitatively in agreement with the trajectories of Argo floats at about 1000 m depth in the area east of 121°E.

RÉSUMÉ?[Traduit par la rédaction] Nous avons rassemblé l'hydrographie, le vent, les Argo et les mesures Argo dans les régions avoisinant le détroit de Luçon. Sur la base des données hydrographiques relevées durant le mois de septembre 1994, nous avons appliqué le modèle océanique amélioré de Princeton utilisant un système de coordonnées « suivant le terrain » généralisé de pair avec une méthode inverse modifiée pour étudier la circulation en septembre. Les observations et la simulation diagnostique produisent une configuration de circulation cohérente dont on peut résumer comme suit les principales caractéristiques dynamiques. (1) Le Kuroshio possède deux branches : le Kuroshio principal existant au-dessus d'une profondeur de 800 m et la partie ouest existant au-dessus d'une profondeur de 400 m. La branche ouest du Kuroshio quitte le courant principal aux environs de 20,5°N et se dirige vers le nord-ouest à travers le détroit de Luçon pour finalement franchir la limite nord du détroit au sud-ouest de Taïwan, ce qui correspond à la trajectoire des bouées dérivantes Argos. (2) Le terme non linéaire dans les équations est important et ne peut pas être considéré négligeable de quantité de mouvement dans la partie nord du détroit de Luçon dans le champ de baroclinité. Lorsqu'on utilise la dynamique non linéaire, l'intrusion vers l'ouest du Kuroshio dans la partie nord du détroit de Luçon est plus incurvée que lorsqu'on utilise la dynamique linéaire. Cependant, le terme non linéaire est plus petit et donc négligeable autour du détroit de Luçon dans le champ de densité homogène. (3) Dans la région allant de 117°E à 119°E et de 20,2°N à 21,7°N, un remous anticyclonique apparaît à l'est des îles Dongsha. (4) Aux profondeurs inférieures à 400 m, la circulation est principalement dominée par le gyre cyclonique à l’échelle du bassin. (5) Dans le domaine de calcul à l'ouest de 121°E, la circulation sous 800 m est principalement dominée par le gyre anticyclonique à l’échelle du bassin. (6) Les eaux de la mer de Chine méridionale s’écoulent vers l'est à travers le détroit de Luçon dans les couches intermédiaires, puis tournent de façon cyclonique pour finalement s’écouler vers le nord dans la région à l'est de l’île Taïwan, ce qui, qualitativement, s'accorde avec la trajectoire des flotteurs Argo à environ 1000 m de profondeur dans la région à l'est de 121°E.     

The diurnal and seasonal characteristics of urban heat island variation in Beijing city and surrounding areas and impact factors based on remote sensing satellite data

Based on the land surface temperature (LST), the land cover classification map,vegetation coverage, and surface evapotranspiration derived from EOS-MODIS satellite data, and by the use of GIS spatial analytic technique and multivariate statistical analysis method, the urban heat island (UHI) spatial distribution of the diurnal and seasonal variabilities and its driving forces are studied in Beijing city and surrounding areas in 2001. The relationships among UHI distribution and landcover categories, topographic factor, vegetation greenness, and surface evapotranspiration are analyzed. The results indicate that: (i) The significant UHI occur in Beijing city areas in the four seasons due to high heat capacity and multi-reflection of compression building, as well as with special topographic features of its three sides surrounded by mountains,especially in the summer. The UHI spatial distribution is corresponding with the urban geometry structure profile. The LST difference is approximately 4-6℃ between Beijing city and suburb areas, comparatively is 8- 10℃ between Beijing city area and outer suburb area in northwestern regions. (ii) The UHI distribution and intensity in daytime are different from nighttime in Beijing city area, the nighttime UHI is obvious. However, in the daytime, the significant UHI mainly appears in the summer, the autumn takes second place, and the UHI in the winter and the spring seem not obvious. The surface evapotranspiration in suburb areas is larger than that in urban areas in the summer, and high latent heat exchange is evident, which leads to LST difference between city area and suburb area. (iii) The reflection of surface landcover categories is sensitive to the UHI, the correlation between vegetation greenness and UHI shows obviously negative.The scatterplot shows that there is the negative correlation between NDVI and LST (R2 = 0.6481).The results demonstrate that the vegetation greenness is an important factor for reducing the UHI,and large-scale construction of greenbelts can considerably reduce the UHI effect.     

Reconstruction of the diagenesis of the fluvial-lacustrine- deltaic sandstones and its influence on the reservoir quality evolution-- Evidence from Jurassic and Triassic sandstones, Yanchang Oil Field, Ordos Basin

The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones of the Yanchang Oil Field in the Ordos Basin is strongly influenced by the burial history and facies-related diagenetic events. The fluvial sandstones have a higher average porosity (14.8%) and a higher permeability (12.7×10?3 ?m2) than those of the deltaic sandstones (9.8% and 5.8 ×10?3 ?m2, respectively). The burial compaction, which resulted in 15% and 20% porosity loss for Jurassic and Triassic sandstones, respectively, is the main factor causing the loss of porosity both for the Jurassic and Triassic sandstones. Among the cements, carbonate is the main one that reduced the reservoir quality of the sandstones. The organic acidic fluid derived from organic matter in the source rocks, the inorganic fluid from rock-water reaction during the late diagenesis, and meteoric waters during the epidiagenesis resulted in the formation of dissolution porosity, which is the main reason for the enhancement of reservoir-quality.     

辽宁及其邻区1900—1949年M≥5级地震参数研究

我们搜集了国际国内地震台网资料、宏观考察资料、地震专题研究报告,对1900—1949年5级以上地震全部进行了核查,重新进行定位处理,并结合宏观考察资料和前人工作成果进行分析研究,得到较为准确的震中位置。通过这项研究,增补了原目录中遗漏的地震,并对目录中的错误进行了修正,从而得到一份较为完整可靠的地震目录。     

三维非均匀地幔中深源电场和磁场的谱理论(Ⅰ)——基本耦合方程组

地球深部研究(SEDI)已经揭示出地幔中的温度和密度在大尺度下的三维非均匀结构,而地幔的电性结构是敏感地依赖于地幔的热状态的.对由地球发电机产生的非定常深源电场和磁场,在三维非均匀地幔中的扩散问题作3系统的探讨.根据球面矢量场的Helmholtz 分解定理,将支配的Maxwell 方程组分解为位势场Φ、环型场T 和极型场S 的基本耦合偏微分方程组,并利用张量球谐函数展开,得到该方程组的谱表示.以此,作为进一步研究核幔电磁耦合理论的必要基础.     

用航空POLDER测量仪获取的方向性信息增强对北方森林冠层的识别(英文)

ＰＯＬＤＥＲ（地球反射极化和方向）仪器在ＢＯＲＥＡＳ实验中曾搭载ＮＡＳＡ的一架Ｃ１３０飞机飞行。在ＢＯＲＥＡＳ的南部地区，ＰＯＬＤＥＲ获取了各种实验场地上的ＢＲＤＦ测量值。森林覆盖地区的大的热点特征，以及十个地区上的镜面反射分量得到了描述。该文通过ＰＯＬＤＥＲ的测量数据，对向常规的光谱特征中加入通过遥感获得的方向性特征后，对各种森林覆盖的分类和区分能力的提高给出了定量化的解。当将方向信息加入常规光谱信息后，采用无监督分类时，类间耦合矩阵的各项显著减小（减小倍数为２－５倍）。这一事实证明了用遥感方向特征可以增强对ＢＯＲＥＡＬ森林覆盖的区分能力。     

集均衡;;汇集干扰;;屏蔽介绍了临钢

,CATV of Lingfen Iron and Steel Company,Lingfen Shanxi 041000,China)This article introduces the design idea and experiences in innovating process of bi-directional HFC network,the design ideas of light pitch point,the optical cable skeleton line and the assignment network.Also the     

Seasonal and annual variation of CO_2 flux above a broad-leaved Korean pine mixed forest

Long-term measurement of carbon metabolism of old-growth forests is critical to predict their behaviors and to reduce the uncertainties of carbon accounting under changing climate. Eddy covariance technology was applied to investigate the long-term carbon exchange over a 200 year-old Chinese broad-leaved Korean pine mixed forest in the Changbai Mountains (128°28'E and 42°24'N, Jilin Province, P. R. China) since August 2002. On the data obtained with open-path eddy covariance system and CO2 profile measurement system from Jan. 2003 to Dec. 2004, this paper reports (i) annual and seasonal variation of FNEE, FGPP and Re; (ii) regulation of environmental factors on phase and amplitude of ecosystem CO2 uptake and release Corrections due to storage and friction velocity were applied to the eddy carbon flux. Lal and soil temperature determined the seasonal and annual dynamics of FGPP and RE separately. VPD and air temperature regulated ecosystem photosynthesis at finer scales in growing seasons. Water condition at the root zone exerted a significant influence on ecosystem maintenance carbon metabolism of this forest in winter. The forest was a net sink of atmospheric CO2 and sequestered -449 g C·m-2 during the study period; -278 and -171 gC·m-2 for 2003 and 2004 respectively. FGPP and FRE over 2003 and 2004 were -1332, -1294 g C·m-2. and 1054, 1124 g C·m-2 respectively. This study shows that old-growth forest can be a strong net carbon sink of atmospheric CO2. There was significant seasonal and annual variation in carbon metabolism. In winter, there was weak photosynthesis while the ecosystem emitted CO2. Carbon exchanges were active in spring and fall but contributed little to carbon sequestration on an annual scale. The summer is the most significant season as far as ecosystem carbon balance is concerned. The 90 days of summer contributed 66.9, 68.9% of FGPp, and 60.4, 62.1% of RE of the entire year.     

Seasonal variations and mechanism for environmental control of NEE of CO_2 concerning the Potentilla fruticosa in alpine shrub meadow of Qinghai-Tibet Plateau

The study by the eddy covariance technique in the alpine shrub meadow of the Qing-hai-Tibet Plateau in 2003 and 2004 showed that the net ecosystem carbon dioxide exchange (NEE) exhibited noticeable diurnal and annual variations, with more distinct daily changes during the warmer seasons. The CO2 emission of the shrub ecosystem culminated in April and September while the CO2 absorption capacity reached a maximum in July and August. The absorbed carbon dioxide during the two consecutive years was 231.4 and 274.8 g CO2·m-2 respectively, yielding an average of 253.1 gCO2·m-2 per year: that accounts for a large proportion of absorbed CO2 in the region. Obviously, the diurnal carbon flux was negatively related to temperature, radiation and other atmospheric factors. Still, minute discrepancies in kurtosis and duration of carbon emission/absorption were detected between 2003 and 2004. It was found that the CO2 flux in the daytime was similarly affected by photosynthetic photon flux density in both years. Temperature appears to be the most important determinant of CO2 flux: specifically, the high temperature during the plant growing season inhibits the carbon absorption capacity. One potential explanation is that soil respiration is enhanced under such condition. Analysis of biomass revealed that the annual net carbon fixed capacity of aboveground and belowground biomass was 544.0 in 2003 and 559.4 g Cm"2 in 2004, which coincided with the NEE absorption capacity (63.1 g C·m-2 in 2003 and 74.9 g C·m-2 in 2004) in the corresponding plant growing season.     

我国东部滨岸侵沉变异规律初探

滨岸地带自然环境多变,地质环境极为脆弱,但在社会经济发展中起着极为重要的作用。着重分析我国东部滨岸侵沉变异特征,研究滨岸侵沉变异地域分异规律与成因规律。