利用T106数值预报产品作江西暴雨动态落区预报

首先将江西测站的降水插值到1°×1°的经纬度网格点上,然后利用1°×1°的T106数值预报产品,对江西网格点上的暴雨送行诊断分析与相关普查,最后建立了江西暴雨动态落区预报模式和动态落区预报流程。     

The Narryer Gneiss Complex of the Yilgarn Block, Western Australia: a segment of Archaean lower crust uplifted during Proterozoic orogeny

The Narryer Gneiss Complex of the Yilgarn Block is a key segment of the Western Australian Precambrian Shield. It is a regional granulite facies terrain comprised of predominantly quartzo-feldspathic gneisses derived from granitic intrusions c. 3.6–3.4 Ga old. Granulite facies metamorphism occurred c. 3.3 Ga ago, and conditions of 750–850°C and 7–10 kbar are estimated for the Mukalo Creek Area (MCA) near Errabiddy in the north. The P–T path of the MCA has been derived from metamorphic assemblages in younger rocks that intruded the gneisses during at least three subsequent events, and this path is supported by reaction coronas in the older gneisses. There is no evidence for uplift immediately following peak metamorphism of the MCA, and a period of isobaric cooling is inferred from the pressures recorded in younger rocks. Pressures and temperatures estimated from metadolerites, which intruded the older gneisses during ‘granite–greenstone’tectonism at about 2.6 Ga and during early Proterozoic thrusting show that the Errabiddy area remained in the lower crust, although it was probably reheated during the younger events. Isothermal uplift to upper crustal levels occurred at c. 1.6 Ga ago, and was followed by further deformation and patchy retrogression of high-grade assemblages. The effects of younger deformation, cooling and reheating can be discerned in the older gneisses, but as there has been no pervasive deformation or rehydration, the minerals and microstructures formed during early Archaean granulite facies metamorphism for the most part are retained. The MCA remained in the lower crust for about 1700 Ma following peak metamorphism and some event unrelated to the original metamorphism was required to exhume it. Uplift occurred during development of the Capricorn Orogen, when some 30–35 km were added to the crust beneath the Errabiddy area. The recognition of early Proterozoic thrusting, plus crustal thickening, suggests that the Capricorn Orogen is a belt of regional compression which resulted from convergence of the Yilgarn and Pilbara Cratons.     

Chloritoid–glaucophane schist in the north Qilian orogen, NW China: phase equilibria and P–T path from garnet zonation

Chloritoid–glaucophane‐bearing rocks are widespread in the high‐pressure belt of the north Qilian orogen, NW China. They are interbedded and cofacial with felsic schists originated from greywackes, mafic garnet blueschists and low‐T eclogites. Two representative chloritoid–glaucophane‐bearing assemblages are chloritoid + glaucophane + garnet + talc + quartz (sample Q5‐49) and chloritoid + glaucophane + garnet + phengite + epidote + quartz (sample Q5‐12). Garnet in sample Q5‐49 is coarse‐, medium‐ and fine‐grained and shows two types of zonation patterns. In pattern I, X_grs is constant as X_py rises, and in pattern II X_grs decreases as X_py rises. Phase equilibrium modelling in the NC(K)MnFMASH system with Thermocalc 3.25 indicates that pattern I can be formed during progressive metamorphism in lawsonite‐stable assemblages, while pattern II zonation can be formed with further heating after lawsonite has been consumed. Garnet growth in Q5‐49 is consistent with a continuous progressive metamorphic process from ～14.5 kbar at 470 °C to ～22.5 kbar at 560 °C. Garnet in sample Q5‐12 develops with pattern I zonation, which is consistent with a progressive metamorphic process from ～21 kbar at 540 °C to ～23.5 kbar at 580 °C with lawsonite present in the whole garnet growth. The latter sample shows the highest P–T conditions of the reported chloritoid–glaucophane‐bearing assemblages. Phase equilibrium calculation in the NCKFMASH system with a recent mixing model of amphibole indicates that chloritoid + glaucophane paragenesis does not have a low‐pressure limit of 18–19 kbar as previously suggested, but has a much larger pressure range from 7–8 to 27–30 kbar, with the low‐pressure part being within the stability field of albite.     

内蒙古地区T639气象要素预报性能评估检验

通过T639模式预报产品在内蒙古地区降水量、2 m温度、相对湿度和10 m风向、风速及降水过程预报效果的适用性研究,得出以下结论,温度和相对湿度预报的准确率较风向、风速明显偏高,温度和相对湿度预报的误差系统偏小,风速预报误差偏大的概率较大;降水量的预报准确率随降水等级增加而递减,对小雨而言,模式漏报率小于空报率,多报降水的偏差和少报降水的偏差相近。在预报要素空间分布上,风向预报的偏差顺时针偏转,其夹角小于45°,温度预报偏差总体偏小,相对湿度预报偏差由西向东表现为“+、-、+、-”的分布特征;小雨和中雨落区预报偏大,暴雨落区预报偏小;贝加尔湖冷涡强度的预报偏强,西太平洋副热带高压的强度预报偏弱,影响范围偏西偏北。     

2014年12月至2015年2月T639、ECMWF及日本模式中期预报性能检验

文章对2014年12月至2015年2月T639、ECMWF（文中简称EC）及日本数值模式的中期预报产品进行了对比分析和检验。结果表明：三个模式对亚洲中高纬环流形势的调整和演变及850 hPa温度转折性变化具有较好的中期预报性能,但都存在随时效增长的系统性偏差;对北方地区温度的预报, EC模式表现为预报较零场偏高,而T639模式表现为预报较零场偏低;对于海平面气压场,EC模式对冷空气前锋的预报与零场更加一致。     

2015年5月大气环流和天气分析

对2015年3—5月T639、ECMWF（文中简称EC）及日本数值模式中期预报产品进行了检验和对比。结果表明：三个模式对亚洲中高纬地区大尺度环流和850 hPa温度的演变和调整均具有较好的预报性能,EC模式对西风指数、850 hPa温度转折过程和变化幅度的预报略优于其他两个模式。对2015年3月31日至4月1日北方地区强沙尘暴天气过程的主要影响天气系统,三个模式预报能力相当,121 h时效都较好地预报出了地面冷高压,但强度和范围与实况有一定偏差。     

Diel patterns of mysid drift (Crustacea: Mysidacea) in the Taieri River estuary,New Zealand

Drifting mysids were sampled to determine diel activity, and whether mysid numbers vary with respect to inflowing and outflowing tides. Samples of drifting mysids were collected at the mouth of the Taieri River, New Zealand, over one 24‐h cycle using five replicate conical drift nets in January 1999. One‐night and 1‐day ebb and flood tide were each sampled. Four species of mysid Tenagomysis macropsis, T. novae‐zealandiae, T. robusta, and an apparently undescribed species of Gastrosaccus sp., were collected over the sampling period. One species, T. robusta, has not previously been collected from estuarine or riverine systems. The undescribed Gastrosaccus sp. was the most abundant of the four species. All four species were more abundant at night, with T. robusta and Gastrosaccus sp. being considerably more abundant in the drift on outflowing tides. In contrast, roughly equal numbers of T. macropsis and T. novae‐zealandiae were observed drifting in and out of the estuary at night.     

塔里木盆地巴楚地区T_7~4界面生屑灰岩微相分析及成岩作用研究

前人对塔里木盆地巴楚地区T74界面的研究主要以在地震反射剖面中大的不整合面形式为基础进行的,对界面具体的岩性、微相和成岩作用研究较少。位于塔里木盆地巴楚县东北方向一间房地区的T74露头剖面为上奥陶统与中—下奥陶统的分界面,岩性以生物碎屑泥粒灰岩和粒泥灰岩为主。镜下分析表明:T74界面生屑灰岩中生物碎屑以棘皮动物(主要为海百合碎片)和介形虫为主,其他生物碎屑包括腕足动物、软体动物、三叶虫、钙球粒、粗枝藻、龙介虫、有孔虫、海绵和苔藓等。通过镜下微相、C-O同位素以及X射线荧光等多种分析方法,认为T74界面地层沉积相为较温暖的低能陆棚相,后期经历了埋藏压实成岩作用、地层抬升后的淡水成岩作用和风化剥蚀作用等。岩石的缝合线发育,孔渗性较好,利于地下流体的运移和渗透,对中—下奥陶统的岩溶发育起着控制作用。     

磁测资料预处理中梯度改正问题探讨

在地质矿产调查、地球物理勘探中,高精度磁测以经济、实用、快捷等特点,在寻找铁磁类矿物及构造中被广泛应用,但在磁测工作中,资料预处理正常场梯度改正比较繁琐,误差又比较大,笔者通过论述和实列对比,指出了目前磁测规范中正常场梯度改正存在的问题,并对正常场梯度改正方法进行了一定的探讨,提出了精度较高的正常场梯度改正方法,同时还提出了一种快捷的磁异常计算方法,使得磁测资料预处理更加简便、准确。