Trend analysis and ARIMA modelling of pre-monsoon rainfall data for western India

Spatial and temporal variability of rainfall over different seasons influence physical, social and economic parameters. Pre-monsoon (March, April and May – MAM) rainfall over the country is highly variable. Since heat lows and convective rainfall in MAM have an impact on the intensity of the ensuing monsoons, hence the pre-monsoon period was chosen for the study. The pre-whitened Mann Kendall test was used to explore presence of rainfall trend during MAM. The results indicate presence of significant (at 10% level) increasing trend in two stations (Ajmer, Bikaner). The practical significance of the change in rainfall was also explored as percentage changes over long term mean, using Theil and Sen's median slope estimator. Forecast using univariate ARIMA model for pre-monsoon months indicates that there is a significant rise in the pre-monsoon rainfall over the northwest part of the country.     

碳酸盐岩油气藏缝洞单元多学科综合划分方法研究——以塔里木盆地轮古11井区为例

对于已进入开发中后期的碳酸盐岩缝洞型油气藏,进行缝洞单元精细研究非常重要。盲目部署加密井,很容易导致因为所在单元的储量已被动用而失利。本文采用的碳酸盐岩缝洞单元多学科综合划分方法是:在有井控制的地区,首先分析井间连通性,然后结合生产动态、常规解析试井、流体性质、数值试井等多学科资料确定缝洞单元边界;在无井控制的地区,影响连通性最重要的主控因素是储层本身的相互连通性,其次才是断裂和裂缝,这时可在连通性约束下进行储层和裂缝预测,并以此为主要依据确定缝洞单元边界。对塔里木盆地轮古油气田轮古11井区划分出80个缝洞单元,其中有55个为储量未动用单元(潜力单元),并部署了一些加密井,已钻的XW1井获得了成功,投产初期日产油95t,不含水。     

Variscan plate dynamics in the circum-carpathian area

Abstract

Magmatic and metamorphic events, imprinted in the crystalline rocks of the so-called core mountains inside the Alpine structure of the Inner Carpathians, allow the re-construction of the history of the Rheic Ocean opening, its development and its final closure. Intra-Carpathian core-mountains are the remnants of the continents that drifted away from Gondwana and docked, initially, with Baltica as part of Avalonia and later on as parts of the Gondwana-derived Armorica Terrane Group or as a separate micro-continent.

All magmatic suites, mafic and felsic, present in the Carpathians core mountains, show similarities to those found in the European Variscan Belt. All described- and dated metamorphic and magmatic events also have equivalents in the evolution of the Caledonian-Variscan Belts of Europe. The most pronounced feature of all Carpathian core mountains is the syn-collisional, multistage I/S granitoid magmatism (370-340 Ma) related to subduction, mafic-magma influx, extensional decompression and slab melting. That episode marked the Laurussia - Gondwana collision and closure of the Rheic Ocean, as in the whole of Central and Western Europe.

The Carpathian core-mountains, currently dispersed inside the Alpine mountain chain, can be considered the broken fragments of the eastern prolongation of the Variscan orogenic belts – possibly part of the Moldanubian Unit.     

2013年12月华东地区持续性霾天气成因分析

2013年12月华东地区发生历史罕见的超过20 d连续重度霾天气过程。本文利用NCEP/NCAR再分析资料、华东地区大气细颗粒浓度资料以及常规气象观测资料对此次天气过程的环流形势、持续机制和前期外强迫因子展开分析。结果表明，此次华东连续重度霾天气和东亚中高纬阻塞高压活动密切相关。2013年12月白令海到鄂霍茨克海阻塞活动加强导致东亚地区天气瞬变扰动异常偏弱，贝加尔湖东侧弱高空脊长时间维持，我国东部地区受弱偏北风影响，大气扩散条件较差，有利于华东本地大气细颗粒物积累和北方霾粒子向华东地区输送。进一步研究表明2013年12月鄂霍茨克海阻塞高压活动偏强可能和前期热带印度洋暖海温异常有关。     

Steady-state frictional geostrophic circulation in a one-layer ocean model with thermodynamics

The governing equations are developed for a steady-state frictional geostrophic inhomogeneous 1.5-layer ocean model, with horizontal velocity field that is linearly sheared in the vertical coordinate. We show that in the adiabatic, thermally non-diffusive limit there are an infinite number of solutions for the temperature and depth fields of the subtropical gyre even with the constraint of identical mass within each temperature range. In the non-adiabatic case, a unique subtropical gyre solution exists that can exhibit a temperature front, containing an unbounded meridional gradient, in the northwest corner of the solution domain. The role of mixing of enthalpy in the western boundary layer (WBL) region was investigated by comparing the two extreme cases of no mixing and complete mixing of enthalpy in this region. Also investigated was the dependence of the meridional heat transport on the air–sea heat exchange coefficient, κ. The temperature field was found to be strongly influenced by mixing. However, both qualitatively and quantitatively, the heat transport is similar in the model with and without mixing. The heat transport attains a single local maximum at κ=κ_c, that lies within values that are oceanographically relevant.     

热带印度洋海温异常单、偶极模态及其相互作用

利用最近50多年的GISST和NCEP的OISST海表温度资料研究了印度洋海温变化的空间分布型和多重时间尺度及其相互作用.结果表明,热带印度洋海温主要存在两种空间分布型,即全海盆符号一致的单极和东、西部符号相反的偶极.单极既存在长期增暖趋势,也存在年际振荡;偶极则以年际变化为主.在去掉由EOF重建的单极后,热带印度洋东、西部海温表现为显著的反相关关系;对17次典型偶极子个例的分析表明,对偶极子本身而言,偶极子的演变更像是一种翘翘板似的局地振荡.单极在长期趋势和年际时间尺度上对偶极的影响是不同的.长期趋势缩短了偶极子的生命期,在冷期,印度洋海温经历了由负单极到正偶极再到负单极的演变,偶极子的异常信号最早出现在热带西印度洋;在暖期,印度洋海温经历了由正单极到正偶极再到正单极的演变,偶极子的异常信号最早出现在热带东印度洋.对年际时间尺度的变化而言,印度洋海温异常由负单极向正偶极再到正单极转换,偶极子位于一种单极向另一种单极的转换过程之中,在此过程中,印度洋海温表现为明显自西向东的传播特征.     

乌蒙山区生物资源持续历史的启示与保护发展的方向

乌蒙山区属古热带北缘,是海陆变迁的海岸线,生物演化至今,造就了丰富的生物资源。人类活动以来,历经了自取自用-半农耕-坝区开发-山区开发的历史时期。由于该区是多民族居住区,又处于国家统一、巩固西南边疆、通向边区的交通要道上,较先进的中原农耕方式最先在此试用。明、清两个朝代的移民与经营,全面开始了生物资源的利用。历代各族人民在适应生存的实践中,找到了持续稳定地增长和利用生物资源的方法。这些,既充满了对自然规律的认识和利用,也为进一步发展提供了技术支持。该区在长江和珠江上游的分水岭上,只有以生态建设为基础,施行保护优先于开发的持续生物资源利用,才能发挥持续性和获得最大效益。概述了上述问题,在生物资源可持续经营上,简要提出了需要研究的基础科学问题和培育新产业的几个方向,并探讨了适应今后持续发展的管理问题。     

大洋钻探与我国地球科学的发展

１９６８－１９８３年的深海钻探（ＤＳＤＰ）导致了地球科学的革命；１９８５年以来的大洋钻探（ＯＤＰ）正在把地球科学提升到地球系统演化的高度。本文从地壳与上地幔的成分、结构与动态和大洋与气候变化的原因与效应两方面简述了大洋钻探的学术成果与研究方向，指出大洋钻探与我国地球科学的密切关系。当前，世界上正在组织＂新世纪大洋钻探＂计划，我国是参与还是旁观？这将在很大程度上决定我国地球科学下世纪的前景。     

利用气象地温资料反演大地热流

利用气象台记录的深度为0.8m,1.6m和3.2m的月平均地温资料,进行Fourier频谱分析,得到定常波和子谐波（变化波）两部分.同时取地表以下为水平分层的均匀双层介质,建立数学模型,根据线性热传导和最优化理论对定常波以及子谐波的振幅谱和相位谱进行联合反演,计算气象台地表附近的定常地温梯度以及地表土壤的热扩散系数等物性参数,并据此计算该地的大地热流值.初步计算结果表明,上述方法得到的某些地区的大地热流值与传统的通过钻孔测量法得到的大地热流值符合得相当好.     

西北太平洋海面高度异常对热带气旋的响应

采用一种海面高度异常(Sea Level Anomaly,SLA)对热带气旋响应的合成分析方法,即根据热带气旋的路径位置和运动方向对海面高度异常进行插值、旋转和平均,得到不同热带气旋强度下,以热带气旋最佳路径点为原点的海面高度异常场.利用该方法,基于Aviso卫星高度计数据和中国气象局热带气旋最佳路径数据,得到了199...