CUTLASS Finland radar observations of the ionospheric signatures of flux transfer events and the resulting plasma flows

The CUTLASS Finland radar has been run in a two-beam special scan mode, which offered excellent temporal and spatial information on the flows in the high-latitude ionosphere. A detailed study of one day of this data revealed a convection reversal boundary (CRB) in the CUTLASS field of view (f.o.v) on the dayside, the direction of plasma flow either side of the boundary being typical of a dawn-cell convection pattern. Poleward of the CRB a number of pulsed transients are observed, seemingly moving away from the radar. These transients are identified here as the ionospheric signature of flux transfer events (FTEs). Equatorward of the CRB continuous backscatter was observed, believed to be due to the return flow on closed field lines. The two-beam scan offered a new and innovative opportunity to determine the size and velocity of the ionospheric signatures associated with flux transfer events and the related plasma flow pattern. The transient signature was found to have an azimuthal extent of 1900 ± 900 km and an poleward extent of 250 km. The motion of the transient features was in a predominantly westward azimuthal direction, at a velocity of 7.5 ± 3 km.     

Observed winds,turbulence, and dispersion in built-up downtown areas of Oklahoma City and Manhattan

Wind and tracer data from the Oklahoma City Joint Urban 2003 (JU2003) and the Manhattan Madison Square Garden 2005 (MSG05) urban field experiments are being analyzed to aid in understanding air flow and dispersion near street-level in built-up downtown areas. The mean winds are separately calculated for groups of anemometers having similar exposures such as “near street level” and “on building top”. Several general results are found, such as the scalar wind speed at street level is about 1/3 of that at building top. Turbulent standard deviations of wind speed components and temperature, and vertical fluxes of momentum and sensible heat, are calculated from sonic anemometers near street level at 20 locations in JU2003 and five locations in MSG05, and from two rooftop locations in MSG05. The turbulence observations are consistent with observations in the literature at other cities, although the JU2003 and MSG05 data are unique in that many data are available near street level. For example, it is found that the local (i.e., at the measuring height) averages about 1.5 and the local averages about 0.25 in the two cities, where is the standard deviation of vertical velocity fluctuations, is the friction velocity, and u is the wind speed. The ratio of temperature fluctuations to temperature scale, , averages about −3 in both cities, consistent with similarity theory for slightly unstable conditions, where is the standard deviation of temperature fluctuations, and is the temperature scale. The calculated Obukhov length, L, is also consistent with slightly unstable conditions near street level, even at night during JU2003. The SF₆ tracer concentration observations from JU2003 are analyzed. Values of for the continuous releases are calculated for each release and arc distance, where is the 30-min average arc maximum concentration, Q is the continuous source emission rate, and u is the spatial-averaged wind speed in the downtown area. The basic characteristics of the JU2003 plot of averaged agree reasonably well with similar plots for other urban experiments in Salt Lake City and London (i.e., at . A is found to be about 3 during the day and about 10 during the night.     

云南玉溪抗旱找水定井典型实例分析

西南大旱百年不遇,山东找水专家组紧急驰援云南抗旱。通过对云南抗旱找水成功定井实例的分析,总结了高原岩溶水和＂红层＂基岩裂隙水的找水勘察工作,并联系云南、四川、山东等贫水区找水定井实践,阐述了贫水区找水定井思路与方法。     

Spatial patterns and environmental associations of deep scattering layers in the northwestern subtropical Pacific Ocean

The mesopelagic communities are important for food web and carbon pump in ocean, but the large-scale studies of them are still limited until now because of the difficulties on sampling and analyzing of mesopelagic organisms. Mesopelagic organisms, especially micronekton, can form acoustic deep scattering layers (DSLs) and DSLs are widely observed. To explore the spatial patterns of DSLs and their possible influencing factors, the DSLs during daytime (10:00–14:00) were investigated in the subtropical northwestern Pacific Ocean (13°–23.5°N, 153°–163°E) using a shipboard acoustic Doppler current profiler at 38 kHz. The study area was divided into three parts using k-means cluster analysis: the northern part (NP, 22°–24°N), the central part (CP, 17°–22°N), and the southern part (SP, 12°–17°N). The characteristics of DSLs varied widely with latitudinal gradient. Deepest core DSLs (523.5 m±17.4 m), largest nautical area scattering coefficient (NASC) (130.8 m2/n mile2±41.0 m2/n mile2), and most concentrated DSLs (mesopelagic organisms gathering level, 6.7%±0.7%) were observed in NP. The proportion of migration was also stronger in NP (39.7%) than those in other parts (18.6% in CP and 21.5% in SP) for mesopelagic organisms. The latitudinal variation of DSLs was probably caused by changes in oxygen concentration and light intensity of mesopelagic zones. A positive relationship between NASC and primary productivity was identified. A four-months lag was seemed to exist. This study provides the first basin-scale baselines information of mesopelagic communities in the northwest Pacific with acoustic approach. Further researches are suggested to gain understandings of seasonal and annual variations of DSLs in the region.     

姬塬地区长8油层组层序地层格架内成岩相展布特征

通过岩心观察并充分利用普通薄片、铸体薄片、阴极发光、X-衍射和扫描电镜等资料,对姬塬地区长8油层组储层的成岩作用、成岩矿物、成岩阶段和成岩演化序列特征等进行了研究。根据成岩作用类型及强度、成岩矿物等将储层划分为绿泥石衬边弱溶蚀、不稳定组分溶蚀、压实致密、高岭石充填和碳酸盐胶结5种成岩相。并通过岩心薄片资料刻度测井归纳出不同成岩相在GR、AC等测井曲线及其组合上的响应特征,由此实现各单井储层成岩相的连续划分。对长8油层组层序界面和基准面旋回与成岩相展布的关系进行了研究,结果表明层序界面附近不稳定组分溶蚀相及高岭石充填相较为发育,且各井之间对比性良好,同时层序界面也控制了碳酸盐胶结;中期基准面旋回的最大湖泛面处均发育井间可对比的压实致密相,长82中期基准面下降半旋回砂体一方面易于遭受溶蚀产生次生孔,另一方面由于受沉积驻留和碎屑组分影响导致压实强度较弱,因此物性总体比长81砂体好。     

The effect of Newtonian cooling on vertically propagating magneto-acoustic waves in a thermally conducting isothermal atmosphere (II)

In this article, we examine reflection, dissipation and attenuation of vertically propagating waves in an isothermal atmosphere under the combined effect of Newtonian cooling, thermal conduction and viscosity with a weak horizontal magnetic field. We consider the case in which the combined effect of viscosity and magnetic field is dominated by that of the thermal conduction and for small values of the Newtonian parameter. As a result, the atmosphere can be divided into three distinct regions that are connected by two transition regions. The lower and middle regions are connected by a semi-transparent barrier and the middle and upper regions are connected by an absorbing and reflecting barrier. In the connecting barriers the reflection and transmission of the waves takes place. The presence of Newtonian cooling effects on the adiabatic region, produces attenuation in the amplitudes of the waves and reduces the energy absorption in the transition regions. The reflection coefficient is determined in the lower and middle regions and the results are discussed in the context of the heating of the solar atmosphere.     

Surfaces of section in the Miranda-Umbriel 3:1 inclination problem

The recent numerical simulations of Tittemore and Wisdom (1988, 1989, 1990) and Dermottet al. (1988), Malhotra and Dermott (1990) concerning the tidal evolution through resonances of some pairs of Uranian satellites have revealed interesting dynamical phenomena related to the interactions between close-by resonances. These interactions produce chaotic layers and strong secondary resonances. The slow evolution of the satellite orbits in this dynamical landscape is responsible for temporary capture into resonance, enhancement of eccentricity or inclination and subsequent escape from resonance. The present contribution aims at developing analytical tools for predicting the location and size of chaotic layers and secondary resonances. The problem of the 3:1 inclination resonance between Miranda and Umbriel is analysed.     

青藏高原古近系牛堡组三段天文周期旋回分析及古湖平面演化研究：以尼玛盆地尼1井为例

青藏高原中部尼玛盆地是一个形成于班公湖-怒江缝合带之上的新生代陆相裂谷盆地。交通不便和勘探程度较低等因素导致其高精度沉积旋回特征和地层学一直鲜有研究。尼1井是盆地内第一口地质探井,通过对该井古近系牛堡组三段的自然伽马测井曲线进行频谱分析,证实了天文轨道周期对盆地内湖相地层的沉积具有显著影响。滤波分析显示牛堡组三段保存了41个短偏心率(～100 kyr)周期,76个斜率(～54 kyr)周期和178个岁差(～23 kyr)周期,平均沉积速率为92.03m/Ma,沉积时限～4.1 Myr。此外,结合Fischer图解与总有机碳含量的变化趋势,确定牛堡组三段湖平面经历了1次长周期的升-降变化过程。综合分析,认为尼玛盆地优质烃源岩的形成主要受天文旋回周期影响下的湖平面变化所控制。     

Holistic approach of GIS based Multi-Criteria Decision Analysis (MCDA) and WetSpass models to evaluate groundwater potential in Gelana watershed of Ethiopia

Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management, planning and development of groundwater resources. Groundwater potential assessment and delineation in a highly heterogeneous environment with limited Spatiotemporal data derived from Gelana watershed of Abaya Chamo lake basin is performed, using integrated multi-criteria decision analysis (MCDA), water and energy transfer between soil and plant and atmosphere under quasi-steady state (WetSpass) models. The outputs of the WetSpass model reveal a favorable structure of water balance in the basin studied, mainly using surface runoff. The simulated total flow and groundwater recharge are validated using river measurements and estimated baseflow at two gauging stations located in the study area, which yields a good agreement. The WetSpass model effectively integrates a water balance assessment in a geographical information system (GIS) environment. The WetSpass model is shown to be computationally reputable for such a remote complex setting as the African rift, with a correlation coefficient of 0.99 and 0.99 for total flow and baseflow at a significant level of p-value<0.05, respectively. The simulated annual water budget reveals that 77.22% of annual precipitation loses through evapotranspiration, of which 16.54% is lost via surface runoff while 6.24% is recharged to the groundwater. The calibrated groundwater recharge from the WetSpass model is then considered when determining the controlling factors of groundwater occurrence and formation, together with other multi-thematic layers such as lithology, geomorphology, lineament density and drainage density. The selected five thematic layers through MCDA are incorporated by employing the analytical hierarchy process (AHP) method to identify the relative dominance in groundwater potential zoning. The weighted factors in the AHP are procedurally aggregated, based on weighted linear combinations to provide the groundwater potential index. Based on the potential indexes, the area then is demarcated into low, moderate, and high groundwater potential zones (GWPZ). The identified GWPZs are finally examined using the existing groundwater inventory data (static water level and springs) in the region. About 70.7% of groundwater inventory points are coinciding with the delineated GWPZs. The weighting comparison shows that lithology, geomorphology, and groundwater recharge appear to be the dominant factors influence on the resources potential. The assessment of groundwater potential index values identify 45.88% as high, 39.38% moderate, and 14.73% as low groundwater potential zones. WetSpass model analysis is more preferable in the area like Gelana watershed when the topography is rugged, inaccessible and having limited gauging stations.     

Dating Neolithic rubble layers from Ba'ja and Basta sites in southern Jordan using luminescence

There is considerable evidence of widespread damage in the 7th millennium habitation sites across Jordan. The origins of this damage are unknown, but the most widely accepted hypothesis associates the resulting rubble and gravel deposits with the Holocene Rapid Climate Change. One way of testing the various hypotheses is to provide a more reliable chronology for the event(s) in question. In this study, we used quartz OSL and feldspar IRSL signals to date accumulative rubble layers at two archaeological sites in Southern Jordan; Ba'ja and Basta. By comparison with the OSL ages, the IRSL ages demonstrate that most of the quartz samples were sufficiently well bleached at deposition to provide accurate ages. Quartz ages show that deposition of the rubble layers took place in different episodes starting around 8.5 ka and 6.0 ka. Ages from Ba'ja site agree with the archaeological expectations of time of deposition. However, the results from Basta are younger than the archaeological expectations, which are based mainly on architectural style and stratigraphy.