纬向平均环流预报的系统性误差及其改进

大量的月预报实例分析表明,纬向平均环流(本指高度场纬向平均分量)存在明显的系统性预报误差,且在总误差中占有可观的份额。国内外其它模式也存在类似的现象。为克服这一困难,本尝试了“结合”(hybrid)的途径。应用重构相空间理论和非线性时空序列预测方法,在大量历史资料的基础上,构造了月尺度逐侯纬向平均高度场(零波分量)距平场的非线性预报模型。然后,将非线性预报和谱模式动力预报结合起来,即将非线性预报结果转化为模式需要的颅报量,再在模式积分过程中的每一步取代其相应部分,实施过程订正。初步试验结果表明,这种途样合效地减少了模式纬向环流的预报误差;特别是通过非线性波流相互作用,还改善了部分波动分量的预报。     

Behaviour of H2O2, NH3, and black carbon in mixed-phase clouds during CIME

We investigated the partitioning of trace substances during the phase transition from supercooled to mixed-phase cloud induced by artificial seeding. Simultaneous determination of the concentrations of H₂O₂, NH₃ and black carbon (BC) in both condensed and interstitial phases with high time resolution showed that the three species undergo different behaviour in the presence of a mixture of ice crystals and supercooled droplets. Both H₂O₂ and NH₃ are efficiently scavenged by growing ice crystals, whereas BC stayed predominantly in the interstitial phase. In addition, the scavenging of H₂O₂ is driven by co-condensation with water vapour onto ice crystals while NH₃ uptake into the ice phase is more efficient than co-condensation alone. The high solubility of NH₄⁺ in the ice could explain this result. Finally, it appears that the H₂O₂–SO₂ reaction is very slow in the ice phase with respect to the liquid phase. Our results are directly applicable for clouds undergoing limited riming.     

The Arctida Craton and Neoproterozoic-Mesozoic orogenic belts of the Circum-Polar region

An attempt is made to characterize an assembly of Arctic tectonic units formed before the opening of the Arctic Ocean. This assembly comprises the epi-Grenville Arctida Craton (a fragment of Rodinia) and the marginal parts of the Precambrian Laurentia, Baltica, and Siberian cratons. The cratons are amalgamated by orogenic belts (trails of formerly closed oceans). These are the Late Neoproterozoic belts (Baikalides), Middle Paleozoic belts (Caledonides), Permo-Triassic belts (Hercynides), and Early Cretaceous belts (Late Kimmerides). Arctida encompasses an area from the Svalbard Archipelago in the west to North Alaska in the east. The Svalbard, Barents, Kara, and other cratons are often considered independent Precambrian minicratons, but actually they are constituents of Arctida subsequently broken down into several blocks. The Neoproterozoic orogenic belt extends as a discontinuous tract from the Barents-Ural-Novaya Zemlya region via the Taimyr Peninsula and shelf of the East Siberian Sea to North Alaska as an arcuate framework of Arctida, which separates it from the Baltica and Siberian cratons. The Caledonian orogenic belt consisting of the Scandian and Ellesmerian segments frames Arctida on the opposite side, separating it from the Laurentian Craton. The opposite position of the Baikalian and Caledonian orogenic belts in the Arctida framework makes it possible to judge about the time when the boundaries of this craton formed as a result of its detachment from Rodinia. The Hercynian orogenic belt in the Arctic Region comprises the Novozemel’sky (Novaya Zemlya) and Taimyr segments, which initially were an ending of the Ural Hercynides subsequenly separated by a strike-slip fault. The Mid-Cretaceous (Late Kimmerian) orogenic belt as an offset of Pacific is divergent. It was formed under the effect of the opened Canada Basin and accretion and collision at the Pacific margins. The undertaken typification of pre-Late Mesozoic tectonic units, for the time being debatable in some aspects, allows reconstruction of the oceanic basins that predated the formation of the Arctic Ocean.     

Textural-structural,mineralogical, isotopic,and age characteristics of Jurassic terrigenous rocks of the northwestern Caucasus (the Belaya River section)

Results of the comprehensive study of structural, lithological, mineralogical, and isotopic characteristics of Lower Jurassic rocks exposed in the Belaya River valley (Adygeya) in meganticlinorium of the Greater Caucasus are presented. Deformation microstructures were studied. Lithological and textural-structural changes in sequences related to intense secondary transformations should affect the state of isotopic systems of rocks. To reveal basic trends in the evolution of isotopic systems, investigation using the K-Ar method was carried out. Clay fraction (less than 1 μm) separated from rocks and bulk samples were analyzed. Cleavage development, approximate value of rock contraction, and isotopic characteristics are compared with the available data on alteration of clay mineral assemblages. Relationship between the degree of rock deformation at the microlevel and calculated K-Ar ages has been established. K-Ar systems of clayey rocks indicate the age of cleavage formation and correspond to the Bajocian-Bathonian contraction period.     

Detrital barytes in the Karoo Supergroup of Southern Africa

Beds of sedimentary barytes are found in late Paleozoic sediments in the northeasternmost part of South Africa and adjoining parts of Rhodesia. The baryte horizon consists of 2 beds of composite thickness of up to 50 cm within a sequence of partly porcellaneous shales. It is dark gray to redbrown in colour, in places also black, and then contains traces of H₂S. It usually consists of fine-grained subrounded tabular grains of detrital origin. This horizon frequently contains aggregates of upward diverging acicular baryte which formed diagenetically within the detrital baryte. The deposit was formed through reworking of semiconsolidated clays containing baryte concretions. Such shales are known to occur to the west of the baryte deposit in contemporaneous sediments.

---

Zusammenfassung In spätpaläozoischen Sedimenten im Nordosten Südafrikas und dem angrenzenden Bereich Rhodesiens treten sedimentäre Barytlagen auf. Die Barytzone besteht aus zwei Lagen mit einer gemeinsamen größten Mächtigkeit von 50 cm, innerhalb einer Abfolge teilweise verkieselter Tonschiefer. Der Baryt ist dunkelgrau bis rotbraun, stellenweise auch schwarz, und enthält dann Spuren von H₂S. Er besteht meist aus feinkörnigen kantengerundeten schwach plattigen Kristallen detritischer Herkunft. Die Zone enthält häufig Aggregate aus nach oben divergierenden nadeligen Barytkristallen, die sich frühdiagenetisch im detritischen Baryt bildeten. Das Vorkommen entstand durch Aufarbeitung von Barytkonkretionen in schwach verfestigten Tonen. Entsprechende Tonschiefer treten in gleichaltrigen Sedimenten westlich des Barytvorkommens auf.

     

Rill erosion along the thalweg of a hillslope hollow: A case study from the cotswold hills,Central England

Rill erosion is an important erosional form on agricultural soils in England, causing large losses of soil, particularly on cultivated slopes. This paper describes a rill system that developed in a small agricultural catchment in north Oxfordshire during the winter of 1992–93. The rill system comprised two components: a system of ‘feeder rills’ along the valley-side slopes, which were the result of flow concentration and erosion along wheelings, and a thalweg rill, which formed along a dry valley bottom as a result of surface runoff concentration from the feeder rills. Total volumetric soil loss from the rill system was 32·28 m³, equivalent to 3·01 m³, ha^?1 for the rill catchment area, or 3·91 t ha^?1. Mean discharge for the thalweg rill and feeder rills, calculated during a storm event, was 31·101s^?1 and 1·171s^?1, respectively. All flows were fully turbulent and supercritical. We emphasize the need for a spatially distributed approach to the study of runoff and erosion at the catchment scale.     

A Hierarchical Hybrid SVM Method for Classification of Remotely Sensed Data

The focus of this work is on developing a new hierarchical hybrid Support Vector Machine (SVM) method to address the problems of classification of multi or hyper spectral remotely sensed images and provide a working technique that increases the classification accuracy while lowering the computational cost and complexity of the process. The paper presents issues in analyzing large multi/hyper spectral image data sets for dimensionality reduction, coping with intra pixel spectral variations, and selection of a flexible classifier with robust learning process. Experiments conducted revealed that a computationally cheap algorithm that uses Hamming distance between the pixel vectors of different bands to eliminate redundant bands was quite effective in helping reduce the dimensionality. The paper also presents the concept of extended mathematical morphological profiles for segregating the input pixel vectors into pure or mixed categories which will enable further computational cost reductions. The proposed method’s overall classification accuracy is tested with IRS data sets and the Airborne Visible Infrared Imaging Spectroradiometer Indian Pines hyperspectral benchmark data set and presented.     

MINERALOGY,PETROLOGY AND CHEMISTRY OF LUNAR ROCK 12039

Rock 12039 belongs to the olivine-depleted group of magmatic rocks characterized by normative and modal SiO₂, absence or very low abundance of olivine, and high FeO/(FeO + MgO), Ti/Cr, and CaO/MgO ratios. Clinopyroxenes in this rock show a complex, essentially continuous, compositional zonation from augite cores through ferroaugite to ferrohedenbergite with an abrupt discontinuity at the pyroxferroite contact and, thus, are different from pyroxene in most other Apollo 12 rocks. Two grains contain thin subcalcic pigeonite zones. Texture, presence of very fine (< 1 μm) exsolution lamallae, and pyroxene zoning indicate a relatively rapid cooling history and pronounced in situ chemical fractionation. Rock 12039, on the basis of mineralogy and bulk composition, is the most highly differentiated member of the olivine-depleted basalt group     

Analysis Of The Disappearing Filament And Flare Of 7 May 1992

By using Yohkoh soft X-ray data, H filtergrams, and radio data, the activation of the disappearing filament and the flare eruption on 7 May 1992 have been studied. Main conclusions are as follows: (1) the emergence of new magnetic flux tends to affect the pre-existing X-ray loops, which usually appear in arcades spanning H filament, changing the magnetic environment of the filament, and then enhance the current in the filament. Therefore newly emerging flux plays a fundamental role in the destabilization of this filament. (2) According to the H data and the rising motion of the filament, the corresponding current variation in the filament has been calculated. It seems that the current interruption may be a possible trigger mechanism for this filament disappearance. (3) The magnetic field strength and the energy flux of energetic electrons in the source region of microwave bursts have been estimated by using the microwave spectrum. During the main phase, the mean magnetic strength and the energy flux of energetic electrons are about 300–400 G and 1×1011 erg cm–2 s –1, respectively. (4) The energy provided by reconnection of the current sheet and the total energy of the current filament are estimated and we show that there is enough energy stored in the filament to feed the 7 May, 1992 flare.     

A Snapshot of the Sun Near Solar Minimum: The Whole Heliosphere Interval

We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar?Cheliospheric?Cplanetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March??C?16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth??s mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum.