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Forecasting the summer rainfall in North china using the year-to-year increment approach

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Science china Earth Sciences 2009年第4期52卷 532-539页

作者： FAN Ke1, LIN MeiJing1,2.& GAO YuZhong3 1 Nansen-Zhu International Research Center, Institute of Atmospheric Physics, chinese academy of Sciences, {2. 10002., china 2.graduate university of the chinese academy of Sciences, beijing 100049, china 3 Heilongjiang Meteorological Administration, Harbin 150030, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China graduate university of the {2. academy of Sciences Beijing 100049 China Heilongjiang Meteorological Administ

A new approach to forecasting the year-to-year increment of rainfall in North china in July-August (JA) is proposed. DY is defined as the difference of a variable between the current year and the preceding year (year-to-year increment). NR denotes the seasonal mean precipitation rate over North china in JA. After analyzing the atmospheric circulation anomalies associated with the DY of NR, five key predictors for the DY of NR have been identified. The prediction model for the DY of NR is established by using multi-linear regression method and the NR is obtained (the current forecasted DY of NR added to the preceding observed NR). The prediction model shows a high correlation coefficient (0.8) between the simulated and the observed DY of NR throughout period 1965-1999, with an average relative root mean square error of 19% for the percentage of precipitation rate anomaly over North china. The prediction model makes a hindcast for 2.00-2.07, with an average relative root mean square error of 2.% for the percentage of precipitation rate anomaly over North china. The model reproduces the downward trend of the percentage of precipitation rate anomaly over North china during 1965-2.06. Because the current operational prediction models of the summer precipitation have average forecast scores of 60%-70%, it has been more difficult to forecast the summer rainfall over North china. Thus this new approach for predicting the year-to-year increment of the summer precipitation (and hence the summer precipitation itself) has the potential to significantly improve operational forecasting skill for summer precipitation.

关键词： annual increment North china precipitation prediction prediction skill

Periodicity of Retzius lines in fossil Pongo from South china

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chinese Science Bulletin 2012年第7期57卷 790-794页

作者： HU Rong1,2.3, ZHAO LingXia1,2.& WU XinZhi2.1 Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, chinese academy of Sciences, {2. 100044, china 2.Laboratory of Human Evolution, Institute of Vertebrate Paleontology and Paleoanthropology, chinese academy of Sciences, {2. 100044, china 3 graduate university of chinese academy of Sciences,{12., china Laboratory of Human Evolution Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China

Periodicity of Retzius lines is a key factor in dental development. In this study, we examined the periodicity of Retzius lines in fossil Pongo from South china using polarized light microscope observation of dental ground sections. The periodicities all of the 15 teeth were 9 d. Comparisons of periodicity were made with extant primates, fossil apes and hominins. Periodicity of fossil Pongo from South china was relatively long but fell within the variation of extant Pongo, Gorilla and modern human, and longer than periodicity of Pan and other extant primates. Fossil Pongo from South china was similar to Lufengpithecus and Sivapithecus, shorter than Gigantopithecus and longer than European and African fossil apes and most early hominins in periodicity. Generally, the periodicities of Asian large-body fossil apes were longer than the periodicities of European and African large-body fossil apes in Miocene. Difference among species and trend of evolution in periodicity were analyzed and discussed. We found that periodicity might gradually increase from Proconsul in early Miocene to several fossil apes in Miocene and then Gigantopithecus in Pleistocene. In addition, this study made correlate analysis between periodicity and body mass respectively in males and females of six extant apes and five fossil apes, and found that periodicity positively correlated with body mass.

关键词：周期性变化中国南方大猩猩化石灵长类动物早中新世类人猿显微镜观察

Improving the accuracy of image-based forest fire recognition and spatial positioning

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Science china(Technological Sciences) 2010年第S1期53卷 184-190页

作者： JIANG LiLi 1,QI QingWen 1,ZHANG An 1,GUO ChaoHui 2.& CHENG Xi 1,3 1 Institute of Geographical Sciences and Natural Resources Research,chinese academy of Sciences,{2. 100101,china 2.4} Center for Resources Satellite Data and Applications,{2. 100094,china 3graduate university of chinese academy of Sciences,{2. {12.,china chinese Acad Sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China china Ctr Resources Satellite Data & Applicat Beijing 100094 Peoples R China chinese Acad Sci Grad Univ Beijing 100049 Peoples R China

Forest fires are frequent natural *** is necessary to explore advanced means to monitor,recognize and locate forest fires so as to establish a scientific system for the early detection,real-time positioning and quick fighting of forest *** paper mainly expounds methods and algorithms for improving accuracy and removing uncertainty in image-based forest fire recognition and spatial ***,we discuss a method of forest fire recognition in visible-light *** are four aspects to improve accuracy and remove uncertainty in fire recognition:(1)eliminating factors of interference such as road and sky with high brightness,red leaves,other colored objects and objects that are lit up at night,(2.excluding imaging for specific periods and azimuth angles for which interference phenomena repeatedly occur,(3)improving the thresholding method for determining the flame border in image processing by adjusting the threshold to the season,weather and region,and (4)integrating the visible-light image method with infrared image ***,we examine infrared-image-based methods and approaches of improving the accuracy of forest fire recognition by combining the spectrum threshold with an object feature value such as the normalized difference vegetation index and excluding factors of disturbance such as interference signals,extreme weather and high-temperature ***,a method of visible analysis to enhance the accuracy of forest fire positioning is examined and realized;the method includes decreasing the visual angle,selecting central points,selecting the largest spots,and judging the selection of fire spots according to the central *** studies are examined and the results are found to be satisfactory.

关键词： forest fire monitoring spatial positioning accuracy improvement

Joint source channel VL coding/decoding for deep space communication networks based on a space trellis

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Science china(Information Sciences) 2011年第9期54卷 1883-1894页

作者： WU WeiRen 1,TU Juan 2.TU GuoFang 1,GAO ShaoShuai 1 & ZHANG Can 1,3 1 School of Information Science and Engineering,graduate university of {2. academy of Sciences,beijing 100049,china 2.beijing Institute of Electronic System Engineering,china Aerospace Science & Industry Corp.,beijing 100854,china 3 State Key Laboratory of Information Security,graduate university of {2. academy of Science,beijing 100049,china 1. School of Information Science and Engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Beijing Institute of Electronic System Engineering China Aerospace Science & Industry Corp. Beijing 100854 China3. State Key Laboratory of Information Security Graduate University of Chinese Academy of Science Beijing 100049 China

This paper presents joint source channel variable length (VL) coding/decoding based on a space *** constructing a joint decoding plane trellis,better decoding performance can be achieved than by using the bit-level decoding ***,the plane trellis is complicated,which results in high decoding complexity for decoding VL turbo *** solve this problem,we construct a space trellis and design a low-complexity joint decoding algorithm with a variable length symbol-a posteriori probability (VLS-APP) algorithm in resource constrained deep space communication *** results show that the proposed approach reduces the decoding complexity by 10% compared with the plane trellis,and the gain of Eb/N0 is about 0.2.dB at SER=***,it provides substantial error protection for variable-length encoded image data.

关键词： joint coding/decoding VL turbo codes space trellis VLS-APP

A puzzle of the radio-quiet quasar PG 1407+2.5:Are optical and X-ray emissions produced from a relativistic jet?

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Science china(Physics,Mechanics & Astronomy) 2011年第1期54卷 183-186页

作者： CHEN Liang 1,2.3 & BAI JinMing 1,2.1 National Astronomical Observatories/Yunnan Observatory,chinese academy of Sciences,Kunming 650011,{2. 2.Key Laboratory for the Structure and Evolution of Celestial Objects,chinese academy of Sciences,Kunming 650011,{2. 3 graduate university of chinese academy of Sciences,beijing 100049,{2. 1. National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China2. Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

PG 1407+2.5 is a radio quiet quasar that has a relativistic *** this report,we show some peculiar properties of its optical and X-ray emissions,which indicate possible non-thermal origins produced from the *** use a simple synchrotron + synchrotron self Compton (SSC) model to fit the emissions with different ratios of energy densities between the magnetic field and electrons (η≡U B/U e),which predicts a different γ-ray *** First LAT AGN Catalog (1LAC) did not include PG 1407+2.5,which indicates an upper limit of γ-ray *** upper limit constrains the ratio to be unreasonably large (η≥10 4-5).This inversely indicates that the optical and X-ray emissions may not be produced from the beaming *** discuss the physical implications of these results.

关键词： active galactic nuclei jet non-thermal emission PG 1407+2.5

Valuations on arithmetic surfaces

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Science china Mathematics 2009年第1期52卷 66-76页

作者： XU Ning Department of Mathematics, graduate School of chinese {2. of Sciences, beijing 100049, china Department of Mathematics Graduate School of Chinese Academy of Sciences Beijing 100049 China

In this paper, we give the definition of the height of a valuation and the definition of the big field ? p,G , where p is a prime and G ? ? is an additive subgroup containing 1. We conclude that ? p,G is a field and ? p,G is algebraically closed. Based on this the author obtains the complete classification of valuations on arithmetic surfaces. Furthermore, for any m ? p,G n ∈ ?, let V m,n be an ∝-vector space of dimension n - m + 1, whose coordinates are indexed from m to n. We generalize the definition of ? p,G , where p is a prime and G ? V m,n is an additive subgroup containing 1. We also conclude that ? p,G is a field if m ? 0 ? n.

关键词： valuation height rank totally ordered group big field transcendental number 14J10

Variation properties of ionospheric eclipse factor and ionospheric influence factor

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Progress in Natural Science:Materials International 2005年第6期15卷 573-576页

作者： ZHAO Chunmei 1,2.*, YUAN Yunbin1, OU Jikun1 and CHEN Jinping3(1. Institute of Geodesy and Geophysics, chinese academy of Sciences, Wuhan 430077,{2. 2. graduate School of chinese academy of Sciences, beijing 100039,{2. 3. Department of Precision Instrument and Mechanology, Tsinghua university, beijing 100084,{2.) Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China graduate School of chinese {2. of Sciences Beijing 100039 China Department of Precision Instrument and Mechanology Tsinghua University Beijing 100084 China

The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

关键词： GPS ionospheric eclipse factor ionospheric influence factor

SHRIMP zircon U-Pb geochronology of early Mesozoic felsic igneous rocks from the southern Lancangjiang and its tectonic implications

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Science china Earth Sciences 2006年第10期49卷 1032-1042页

作者： PENG Touping1,2. WANG Yuejun1, FAN Weiming1, LIU Dunyi3, SHI Yuruo3 & MIAO Laicheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, chinese academy of Sciences, Guangzhou 510640,{2. 2. graduate university of chinese academy of Sciences, beijing 100039,{2. 3. SHRIMP isotope Laboratory, chinese academy of Geological Sciences, beijing 100037,{2. 4. Institute of Geology and Geophysics, chinese academy of Sciences, beijing 10002.,{2. Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China graduate university of {2. academy of Sciences Beijing China SHRIMP isotope Laboratory Chinese Academy of Geological Sciences Beijing China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

The SHRIMP zircon U-Pb geochronology of three typical samples, including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang, western Yunnan Province. The analyses of zircons for the biotite monzonitic granites from the northern (02.X-137) and southern (2.JH-10) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 2.6Pb/2.8U ages of 2.9.4 ± 3.0 Ma and 2.0.4 ± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02.X-95) from the Manghuai Formation give a weighted mean 2.6Pb/2.8U age of 2.1.0 ± 5.0 Ma. These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age. In combination with other data, it is inferred that both were generated at a narrow age span (~2.0 Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 2.6Pb/2.8U apparent age of 1977±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite (southern Lincang batholith), indicative of devel- opment of the early Proterozoic Yangtze basement in the region. These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys, western Yunnan Province.

关键词： SHRIMP zircon U-Pb dating, Middle Triassic, Lincang granitic batholith, Manghuai Formation rhyolite, southern Lancangjiang.

CH_4 uptake flux of Leymus chinensis steppe during rapid growth season in Inner Mongolia,china

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Science china Earth Sciences 2010年第7期53卷 977-983页

作者： GENG YuanBo1, LUO GuangQiang1,2.& YUAN GuoFu1 1 Institute of Geographic Sciences and Natural Resources Research, chinese academy of Sciences, {2. 100101, china 2.graduate university of chinese academy of Sciences, beijing 100049, china 1. Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The influence of near ground atmosphere CH4 concentration, soil water content, soil Eh, plants, soil temperature, and pH on CH4 uptake flux of Leymus chinensis steppe during rapid growth season was studied using field in-situ measurement in Xilin River basin of Inner Mongolia, china. The results showed that CH4 uptake flux was positively correlated with near ground atmosphere CH4 concentration and soil Eh but negatively correlated with soil water content. Precipitation may decrease the CH4 flux by increasing the soil water content. The average fluxes of three treatments during the observation period were 1.52.(natural conditions, 1.51 (aboveground plants were excluded), and 2.00 mg m?2.d?1 (all plants were removed), respectively. The difference between the CH4 flux of natural condition treatment and that of removing aboveground plants treatment is small, whereas the flux of removing all plants treatment is larger than the other two treatments. This means that the contribution of aboveground plants to CH4 uptake flux is smaller than that of roots or roots-removing process. CH4 uptake flux is not sensitive to soil temperature and the narrow-ranged soil pH (6.36–7.86). The Leymus chinensis steppe acts as a sink for CH4, and thus more studies should be focused on its affecting factors and related mechanisms.

关键词： CH4 uptake flux Leymus chinensis steppe affecting factors static opaque chamber/gas chromatography method