Investigation of the impacts of vegetation distribution and evaporative cooling on synthetic urban daytime climate using a coupled LES—LSM model

Local flow properties and regional weather or climate are strongly affected by land‐atmosphere interactions of momentum and scalars within the daytime convective boundary layer (CBL). In this study, we investigate the impact of green space scale on the daytime atmospheric boundary layer (ABL) over a synthetic urban domain using a recently developed large‐eddy simulation‐land surface model (LES–LSM) framework. With the use of realistic soundings as initial conditions, a series of numerical experiments over synthetic urban surfaces with varied scale of vegetated area is performed. Simulated micrometeorological properties, surface fluxes, basic CBL characteristics, and cloud distribution are analysed. The results show reference‐level air potential temperature and specific humidity as well as surface fluxes over green space are significantly affected by the scale of green space in the urban domain. The surface organization due to vegetated area scale also has impacts on horizontally averaged scalar and momentum profiles; however, the magnitude in this study is smaller than the results of a previous study using a set of offline surface fluxes as the lower boundary condition for LES. In addition, even though this study only performs a daytime diurnal cycle, the impact of green space scale on cloud distribution in simulations is significant. The cases with more organized green space yield lower‐elevated cumulus cloud and larger‐cloud cover fraction, which impacts the energy budget at the top of boundary layer and, in turn, could lead to additional surface cooling with respect to longer‐term weather and climate. Copyright © 2010 John Wiley & Sons, Ltd.     

Impact of seasonal variations in hydrological stresses and spatial variations in geologic conditions on a TCE plume at an industrial complex in Wonju,Korea

Spatial and temporal variations in a trichloroethylene (TCE) plume at an industrial complex in Wonju, Korea, were examined based on hydrogeological data and seven rounds of groundwater quality data collected over a year. The site has considerable vertical heterogeneities; the top layer of soil is covered by impermeable paving material at several locations, followed by a series of reclaimed or residual soil layers, and with weathered rocks to the crystalline biotite granite at the bottom. Areal heterogeneity in the surface conditions plays an important role in controlling groundwater recharge. The heterogeneity structure is influenced by complex surface conditions paved with asphalt and concrete. Owing to the presence of limited recharge area and concentrated summer precipitation events, the effects of seasonal variations on groundwater hydraulics tend to diminish with distance from the recharge area. This result was established by analysing the influence of the contrasting surface recharge conditions between the near‐source zone and the far zone, and the seasonally concentrated precipitation on the transport patterns of a TCE plume. In addition, variations in the plume's downstream contaminant flux levels were also analysed along a transect line near the source zone. The results show that the general tendency of the TCE plume contaminant concentration and mass discharges were reproducible if we account for seasonal recharge variations and the associated changes in the groundwater level. During recharge events, the TCE concentration variations appear to be influenced by leaching of the residual dense non‐aqueous‐phase liquid (DNAPL) TCE trapped in the unsaturated zone. This result shows that seasonal variations in contaminant plume near the source zone is inevitable at this site, and that these variations indicate the presence of residual DNAPL at or above the water table, at least in some isolated locations. Copyright © 2011 John Wiley & Sons, Ltd.     

Petrology and isotope geology of mafic to ultramafic metavolcanic rocks of the Brusque Metamorphic Complex,southern Brazil

The Brusque Metamorphic Complex (BMC) is one of the main units of the Tijucas Terrain within the Dom Feliciano Belt, located in the state of Santa Catarina in southern Brazil. In the Itapema region, the BMC is composed chiefly of metasediments, including subordinate metabasalts, meta-ultramafic rocks, and clinoamphibole schists. The metavolcanic rocks form 4 m-thick lenses interlayered with metapelites and calc-silicate schists. Based on the observed textures and the associated structural, bulk-rock geochemical, and mineral chemical data, these metamafites and ultramafites were ancient lava flows of tholeiitic basalts and ultramafic cumulates. The mineral parageneses of the metabasalts are albite?+?actinolite?+?chlorite?+?epidote?+?titanite?+?magnetite and oligoclase?+?hornblende?+?epidote?+?titanite?+?magnetite, indicating progressive transformations produced under greenschist to amphibolite facies conditions. Volcanogenic metasediments show the same geochemical patterns as the metabasalts, whereas the metamorphosed ultramafic rocks consist of cumulates generated by crystal fractionation and flow segregation. The studied rocks show similar rare-earth element (REE) patterns, characterized by clearly higher normalized contents of light REEs compared with heavy REEs, without Eu anomalies in the metabasalts and positive Eu anomalies in meta-ultramafic rocks and volcanogenic metasediments. In accordance with the trace element contents that indicate a within-plate nature, the corresponding mafic melts apparently formed in the mantle by partial fusion and were subsequently enriched with crustal components during ascent into the sialic crust. The analysed ¹⁴³Nd/¹⁴⁴Nd and ⁸⁷Sr/⁸⁶Sr ratios lie between 0.5123 and 0.5126 and 0.7067 and 0.7086, respectively, and are thus typical of tholeiitic basalts of the continental plateau type. Initial ?Nd₍₉₃₆₎ values and derived model ages (T _DM) between 1028 and 1762 million years support a mantle source or sources, with extraction and emplacement in the Neoproterozoic. Field relations and geochemical data (including isotopic data) indicate the generation of the studied mafic and ultramafic rocks in a continental rift. In the regional geologic context, the formation of the BMC volcanic and metasedimentary units marks a period of fragmentation of the Palaeoproterozoic continental crust. This extensional event is preserved regionally in gneisses from the Santa Catarina Granulitic Complex and the Camboriú Complex.     

河床地形影响潜流交换作用的数值分析

选取对潜流交换具有重要影响的河床地形作为主要研究内容,采用数值模拟(MODFLOW程序)的方法研究在河床横剖面地形不均匀的条件下,潜流交换量的空间分布以及地下水流场的演变机制。结果表明:在河床地形起伏不均的情况下,潜流交换量更易发生在河道的深水区域;地下水流向受河床地形影响较小;近河床界面处的地下水流速受地形起伏影响剧烈,深水区域的地下水流速远大于浅水区地下水流速;通过与现场试验结果对比分析,得出河床地形起伏是引起潜流带渗透系数非均质现象的重要原因之一。     

苏德尔特油田铜钵庙组—南屯组油层多级次基准面旋回格架中的储层非均质性特征

依据不整合面和沉积作用转换面,可将苏德尔特油田铜钵庙组-南屯组油层划分为3个长期基准面旋回和13个中期旋回,并可进一步将主要含油层Ⅰ、Ⅱ油组划分为26个短期旋回(小层)。油组和中期旋回具有良好的对应关系。在多级次基准面旋回格架中,储层非均质性分布表现出明显的规律性,短期旋回不同的结构样式决定了4种层内物性变化模式;中长期旋回及其位置控制储层层间和平面非均质性,基准面上升早期、下降末期及最低位置时,砂体单层厚度大、连续性强、储层物性好,而基准面上升至高位时,因沉积作用能量减弱而砂体储层物性较差。     

准噶尔阜康东部斜坡区中侏罗统头屯河组高分辨 层序地层格架内储集层宏观非均质性研究

应用高分辨层序地层对准噶尔东部阜康东部斜坡区中侏罗统头屯河组进行层序的划分,共划分出1个长期基准面旋回、三个中期基准面旋回和10个短期基准面旋回。在中期层序地层格架下,按照层内非均质性、层间和平面三个级次对各层序进行非均质性剖析,发现储层宏观非均质性具有一定的规律性,主要在MSC2层序内表现明显。MSC2储集砂体的非均质程度最高,基准面上升初期及下降末期,储集砂体厚度较大,物性较好,是勘探开发有利区域。各层序的非均质性主要受到A/S值变化所影响。     

Research on Accuracy Validation and Calibration Methods of TRMM Remote Sensing Precipitation Data in Irrawaddy Basin

TRMM daily precipitation data were validated compared to thirteen precipitation observation station data in Irrawaddy basin, and a calibration method of TRMM 3B42 data based on water balance concept was developed. SWAT model was used to calculate water balance, and then the TRMM data calibration ratio was inferred based on it. Average slope of sub-basin was the independent variable, and calibration ration was the dependent variable for the regression analysis. The calibration ratio of sub-basins without hydrological observation stations were calculated according to the average slope, and then the TRMM precipitation were calibrated according to the ratio in the whole basin. Results showed that TRMM annual and monthly precipitation had a highly correlation with observed data, but had a bad bias. Annual precipitation of TRMM precipitation after calibration were nearly the same as observed; monthly precipitation curve were similar with observed. Daily precipitation forecast rank was improved from medium to well, and there were 2 station forecast bad, 7 forecast well and 4 forecast medium before calibration, but 6 forecast well, 2 forecast medium and 5 forecast excellent after calibration. The results proved that TRMM data precision were highly improved over different temporal scales in Irrawaddy basin through this method, data for hydrological and water resources analysis were also provided.     

基于高精度DEM的地形监测方法研究

基于非接触的遥感手段的DEM采集精度越来越高,如何运用好高精度DEM成为关键.介绍了包括LiDAR、合成孔径雷达、摄影测量技术等遥感手段采集高精度DEM的方式及处理流程.DEM在地质、地貌、土壤、国防建设方面均有着广泛的应用,就基于高精度DEM的地形监测方法展开试验和讨论,对比不同分辨率（1,10,30 m） DEM影像展示效果,得出高精度DEM在展示与分析方面的优点,通过计算山体阴影、坡度、地形曲率,研究了基于单期高精度DEM的不同地形监测方法.     

Dupal Anomaly and Identification using Nd-Hf Isotopes

The Dupal anomaly has attracted widespread attention since being discovered and is regarded as the most direct manifestation of mantle inhomogeneity at present. From the initially defined anomalies limited to the southern hemisphere to the global scale, the criteria for identifying anomalies defined by Pb isotopes have also been adjusted, providing an important method and reference for the study of the mantle evolution. Pearce and Peate (1995) proposed the method of Nd-Hf isotope and element ratio to identify the Dupal anomaly. The Nd-Hf method also offers a possible way to discriminate the mantle region of arc magmatism through the correction of Nd in the subduction process. This paper introduces the concepts and determination methods of the Dupal anomaly, and reports new Hf isotopic data of MORB-type rocks with Dupal signature in the several Tethys ophiolites. Our results of Nd-Hf method are in good agreement with those of previous Pb isotope identification. Moreover, origins and their controversy of Dupal anomaly are reviewed, and possible internal connections between Dupal anomalies and the two Large Low Shear Velocity Provinces (LLSVPs) in the lower mantle are discussed in depth. Further studies on origin and evolution of the Dupal anomaly are suggested, especially using integrated approach of Hf-Nd and Pb isotopes.     

如何使地质数据更具代表性

由于地质过程的复杂性,导致了油气储层分布的非均质性。钻井总是被优先设计在有利储层的部位,从而导致了钻井分布的不均匀,进而使得获取的地质数据在空间上的分布也是不均匀的。如果不考虑这种地质数据分布的不均匀性,可能会导致数据统计结果的失真。这里介绍了二种方法解决这个问题:网格去丛聚方法和多边形去丛聚方法。这二种方法的基本思想都是给密集的数据以较低的权值,而给稀疏的数据较大的权值。应用这二种方法分别对石南油田某井区的微相类型比例及孔隙度分布进行了分析,结果表明,经过处理后的地质数据更能真实地反映实际情况。