THE EFFECTS OF BOGUS TYPHOON AND OBSERVED OCEANIC DATA ON THE ABILITY OF T_(213)L_(31) TO PREDICT TC TRACK

The abilities of typhoon (TC) track prediction by a medium-range forecast model T213L31 at National Meteorological Center are analyzed and its ability to improve its TC forecasts is discussed. The results show that about 57% of the TCs could be predicted by T213L31 but the initial position errors are large.The 43% area without the prediction of TC tracks is concentrated between 13°N and 20°N and east of 120°E and lack of conventional observation data is the main reason for the absence of TC prediction in this area.The adding of bogus TC could improve the ability of TC track prediction when there is no TC vortex in the analysis field, but could only have positive effects on the short-range TC track prediction when there is TC vortex in the T213L31 analysis field.     

2007年夏季川渝与江淮流域MCS分布与日变化特征

2007年夏季川渝地区及江淮流域持续性降水、极端强降水和强对流事件频发.利用强暴雨发生时段2007年6月28日至7月26日逐时FY-2C红外TBB资料对这两个地区及周边区域(25°～38°N、100°～130°E)进行普查,共获得570个生命史≥3小时的中尺度对流系统(MCS).MCS的定义为-52℃ TBB闭合等值线内TBB≤-52℃的面积≥400km~2,不区分形状与生命史.MCS识别由计算机自动完成,MCS追踪由人工完成.普查结果发现,云南西北部至四川西部、四川东部与重庆、云贵高原东部和广西北部山区至洞庭湖、淮河流域四个区域是MCS活跃区,但淮河流域又有三个波动状MCS活跃中心.普查区域内总体MCS和川渝地区活动最频繁的MCS持续时间为3～7小时,但江淮流域活动最频繁的MCS生命史为4～9小时.按时间尺度将570个MCS分成三类,第一类MCS生命史3～5小时,第二类MCS生命史6～11小时,第三类MCS生命史≥12小时.三类MCS的地理分布特征及触发机制各不相同:第一、二类MCS在西太平洋副高平均位置的内、外侧都有发生,它们的发生、发展及移动受中尺度因素影响明显,可能与地形、中尺度辐合线等有关;第三类MCS发生在西太平洋副热带高压平均位置的外侧,其发生、发展及移动路径受天气尺度环境控制因素显著.三类MCS日变化具有明显不同的日变化特征.三类MCS的形成高峰都出现在午后.第一类MCS无显著的夜发性特征,第二、三类MCS有较显著的夜发性特征.第一、二类MCS在午后最活跃,但第三类MCS活动最活跃时段在下半夜(18UTC).川渝地区和江淮流域的MCS都具有多峰型日变化特征,但二者的活跃时段有所不同.本文还给出了2个引发强降水的MCS典型个例及1个长生命史MCS演变特征.     

一种风暴轴逐日监测的方法及应用

提出了一种风暴轴逐日监测的方法, 可以获得逐日的风暴轴变化情况。并且采用了动态阈值定义了新的风暴轴的强度和位置指数, 从而可以有效对比不同层次、不同区域、不同时间的风暴轴变化情况。利用NCEP/NCAR再分析资料进行了监测结果的诊断分析。结果表明:各气象要素滤波结果都能表现出两个风暴轴主体, 但有位置上的差别。同时可以利用逐日检测的结果求得逐候、逐月的风暴轴监测结果。在不同高度的风暴轴中, 250~300 hPa高度的风暴轴强度最大, 850 hPa有极小值出现, 各层风暴轴强度呈现准正压结构。采用500 hPa高度场风暴轴监测结果做代表, 讨论了两大洋上各自的风暴轴偏强/偏弱、偏东/偏西、偏北/偏南时同期大气环流的500 hPa高度场和300 hPa纬向风场差异。     

埋深对恐龙化石的影响效果研究

已发现的恐龙化石大多数埋藏在不同深度的地层中,不同埋深化石所受风化破坏程度不尽相同。为深入研究恐龙化石的风化机理,探究恐龙化石的保护措施和方法,重点分析埋深产生的侧向压力对恐龙化石强度和破坏特性的影响。通过有限差分软件FLAC3D进行数值模拟,揭示埋深因素对恐龙化石保存的影响程度。试验结果表明:围岩对恐龙化石施加的侧向压力是影响恐龙化石变形和强度特性的一个重要因素。在弹性变形阶段,恐龙化石的初始强度、峰值强度随侧向压力的增大而不断增大。当应力超过了恐龙化石极限强度后进入塑性变形,其初始强度、峰值强度逐渐减小,最终达到残余强度。     

重庆云阳新津乡中侏罗统新田沟组恐龙的发现及沉积环境

在重庆市云阳县新津乡中侏罗统新田沟组中发现了大量恐龙化石,且恐龙化石产出层位呈现出与双壳类、鱼类、龟鳖类和蛇颈龙类化石整体混杂埋藏的特征,这是新田沟组中首次发现。通过野外实测剖面、岩石特征、沉积构造、古生物特征、粒度特征,初步判定研究区新田沟组为滨-浅湖亚相沉积,局部为洪泛亚相。重庆地区新田沟组古生物化石组合的首次发现为四川盆地中生代古生物化石及其古环境的研究提供了更多依据。     

基于恐龙足迹重建攀西地区白垩纪恐龙动物群

攀西地区没有白垩纪恐龙骨骼化石记录,对该区白垩纪恐龙动物群组合的认识尚属空白。1991年,攀西地区首次发现了恐龙足迹,此后陆续发现了8个足迹点。这些足迹点共发现9种不同的非鸟恐龙足迹(6种非鸟兽脚类、1种蜥脚类和2种鸟脚类足迹),以及翼龙和龟类足迹。共11种足迹形态类型由185道行迹(与孤立足迹)组成,可能代表着同等数量的造迹者。其中飞天山组的组合多样性最强,小坝组和雷打树组较弱。这个相对全面的足迹数据库,为该地区白垩纪四足类的古生态学普查提供了动物群的组成信息,这在该缺乏骨骼化石的地区显得尤为重要。     

Morphological and Phylogenetic Study Based on New Materials of Anchiornis huxleyi (Dinosauria,Theropoda) from Jianchang,Western Liaoning,China

Anchiornis huxleyi, which is a member of the Middle–Late Jurassic Yanliao Biota, is the smallest feathered dinosaur ever known. It has been described as a critical link between feathered dinosaurs and birds. Recent studies, including those of Anchiornis, Xiaotingia, Eosinopteryx and Aurornis, challenged Archaeopteryx as the most basal bird. The new Anchiornis huxleyi specimens that are described in this paper show some minor different characters compared to previously reported Anchiornis specimens, which has revised the character list of Anchiornis and indicates a different phylogenetic point from former opinions.     

A New Ootype of Dinosaur Egg (Faveoloolithidae: Duovallumoolithus shangdanensis oogen. et oosp. nov.) from the Late Cretaceous in the Shangdan Basin,Shaanxi Province,China

A new ootype collected from the Upper Cretaceous Lijiacun Formation in the Shangdan Basin, Shaanxi Province is described in this paper. Based on general external shape, size, eggshell thickness and honeycomb‐like eggshell microstructure, eggs are referable to the oofamily Faveoloolithidae. Compared with other members of Faveoloolithidae, specimens described in this paper show special characteristics: adjacent pores are usually separated by two eggshell units between which often develop interspaces; columnar eggshell units are relatively closely arranged in radial view. According to these characteristics, we erect a new oogenus and a new oospecies: Duovallumoolithus shangdanensis oogen. et oosp. nov. The new discovery expands the diversity of Faveoloolithidae.     

四川西昌盆地白垩纪恐龙足迹群的新发现

四川西昌盆地白垩系小坝组尚未发现骨骼化石记录,其白垩系恐龙动物群的信息全赖于足迹化石。2017年,在喜德县洛甘发现小坝组迄今最大型的恐龙足迹群。该足迹点保存了大量的兽脚类足迹。足迹保存条件较差,但具备了基本的形态学特征。总体来看,兽脚类足迹具有尺寸较小(8~13cm),中等中趾前凹(0.5~0.6)和第Ⅱ趾和第Ⅳ趾间较宽趾间角(70°~100°)的特征;少量足迹保存了跖骨垫。初步分析认为,洛甘兽脚类足迹与四川盆地夹关组的兽脚类足迹Eubrontes和Grallator形态类型相似,为两地在白垩纪中期具有类似的恐龙动物群的观点提供了新的证据。该发现对于西昌盆地的古气候、古地理和地层对比都具有重要的意义,足迹详细分类还有待进一步研究。     

Theropod assemblages and a new ichnotaxon Gigandipus chiappei ichnosp. nov. from the Jiaguan Formation,Lower Cretaceous of Guizhou Province,China

A newly discovered Jiaguan Formation(Lower Cretaceous) tracksite from the Linjiang region of Guizhou Province, China, reveals the first example of a Cretaceous track morphotype attributable to the non-avian theropod ichnogenus Gigandipus, here named Gigandipus chiappei ichnosp nov. The theropod dominated locality also reveals the second report of the avian theropod ichnogenus Wupus, one of the largest avian traces currently known from the Lower Cretaceous. The Linjiang site provides evidence to support previous interpretations of a distinctive Lower Cretaceous theropod-dominated ichnofauna that was widespread in China and East Asia and highlights the similarity between Lower Cretaceous theropod ichnotaxa in East Asia and those found in the Lower Jurassic both in East Asia and elsewhere. These similarities in turn create various ichnotaxonomic challenges familiar to researchers working on theropod tracks, and we recommend caution in the naming of new theropod ichnotaxa at the ichnogenus level.