The Flexible Global Ocean-Atmosphere-Land system model, Spectral Version 2: FGOALS-s2

The Flexible Global Ocean-Atmosphere-Land System model, Spectral Version 2 (FGOALS-s2) was used to simulate realistic climates and to study anthropogenic influences on climate change. Specifically, the FGOALS-s2 was integrated with Coupled Model Intercomparison Project Phase 5 (CMIP5) to conduct coordinated experiments that will provide valuable scientific information to climate research communities. The performances of FGOALS-s2 were assessed in simulating major climate phenomena, and documented both the strengths and weaknesses of the model. The results indicate that FGOALS-s2 successfully overcomes climate drift, and realistically models global and regional climate characteristics, including SST, precipitation, and atmospheric circulation. In particular, the model accurately captures annual and semi-annual SST cycles in the equatorial Pacific Ocean, and the main characteristic features of the Asian summer monsoon, which include a low-level southwestern jet and five monsoon rainfall centers. The simulated climate variability was further examined in terms of teleconnections, leading modes of global SST (namely, ENSO), Pacific Decadal Oscillations (PDO), and changes in 19th–20th century climate. The analysis demonstrates that FGOALS-s2 realistically simulates extra-tropical teleconnection patterns of large-scale climate, and irregular ENSO periods. The model gives fairly reasonable reconstructions of spatial patterns of PDO and global monsoon changes in the 20th century. However, because the indirect effects of aerosols are not included in the model, the simulated global temperature change during the period 1850–2005 is greater than the observed warming, by 0.6°C. Some other shortcomings of the model are also noted.     

Preliminary evaluations of FGOALS-g2 for decadal predictions

The Flexible Global Ocean-Atmosphere-Land System model, Grid-point Version 2 (FGOALS-g2) for decadal predictions, is evaluated preliminarily, based on sets of ensemble 10-year hindcasts that it has produced. The results show that the hindcasts were more accurate in decadal variability of SST and surface air temperature (SAT), particularly in that of Nin o3.4 SST and China regional SAT, than the second sample of the historical runs for 20th-century climate (the control) by the same model. Both the control and the hindcasts represented the global warming well using the same external forcings, but the control overestimated the warming. The hindcasts produced the warming closer to the observations. Performance of FGOALS-g2 in hindcasts benefits from more realistic initial conditions provided by the initialization run and a smaller model bias resulting from the use of a dynamic bias correction scheme newly developed in this study. The initialization consists of a 61-year nudging-based assimilation cycle, which follows on the control run on 01 January 1945 with the incorporation of observation data of upper-ocean temperature and salinity at each integration step in the ocean component model, the LASG IAP Climate System Ocean Model, Version 2 (LICOM2). The dynamic bias correction is implemented at each step of LICOM2 during the hindcasts to reduce the systematic biases existing in upper-ocean temperature and salinity by incorporating multi-year monthly mean increments produced in the assimilation cycle. The effectiveness of the assimilation cycle and the role of the correction scheme were assessed prior to the hindcasts.     

基于SRTM天气雷达净空环境评估算法误差分析

采用航天飞机雷达地形测绘使命(SRTM)高程数据对天气雷达净空环境进行评估,可有效提高雷达选址评估效率。利用人工测量数据和SRTM数据进行天气雷达净空环境评估对比试验,结果表明基于该数据的天气雷达净空环境评估算法总体与人工测量方法具有较好的一致性。采用方位矫正和距离矫正算法后,基于该数据的天气雷达净空环境评估算法精度明显提高。     

基于星间加速度法精确和快速确定GRACE地球重力场

本文基于星间加速度法(IRAM),利用预处理共轭梯度迭代法(PCCG)开展了地球重力场恢复的模拟研究.第一,通过9点Newton-Gregory插值法得到星问加速度,并联合星间距离、星间速度和星间加速度建立了卫星观测方程.第二,在120阶处,恢复GRACE-IRAM累计大地水准面的精度为7.215 cm.第三,分析了在...     

利用X射线脉冲星进行同步定位/授时的可观性分析

将星载时钟钟差增广为状态向量,根据非线性系统的可观性秩条件判据,从理论上证明了利用X射线脉冲星进行同步定位/授时是可观的,为X射线脉冲星自主导航的工程应用提供了理论依据。     

广东省天堂铜铅锌多金属矿床矽卡岩矿物学特征及其地质意义

天堂矿床是粤西地区以泥盆系上统天子岭组灰岩为围岩的大型矽卡岩型铜铅锌多金属矿床,矿体呈似层状、层状、透镜状、不规则状等产出在矽卡岩和矽卡岩化大理岩中,矿区发育石榴子石、透辉石、绿帘石、硅灰石、绿泥石等蚀变矿物,金属矿物主要包括黄铜矿、黄铁矿、方铅矿和闪锌矿等。本文以主要矽卡岩矿物为研究对象,利用电子探针技术对其矿物学特征进行研究。电子探针分析结果表明:天堂铜铅锌多金属矿床矽卡岩属于交代矽卡岩中典型的钙矽卡岩。石榴子石以钙铝榴石-钙铁榴石系列为主,从早到晚具有从钙铝榴石为主到钙铁榴石为主的演化趋势,说明成矿流体由酸性向碱性演化。辉石以透辉石为主,石榴子石和辉石的矿物组分分别为Adr4.60~96.47Grs2.10~94.28(Prp+Sps)0.41~3.88和Di88.51~95.09Hd3.31~9.76Jo0.28~3.98,其较大的成分变化特征反映出矽卡岩不是在一个完全封闭的平衡条件下形成的。帘石主要为绿帘石,含有少量的黝帘石。矿物成分分析表明辉石的Mn/Fe比值和矿化金属元素存在一定的联系。通过矽卡岩矿物学特征分析,进一步证实天堂铜铅锌多金属矿床是花岗岩类岩浆交代灰岩而形成的典型矽卡岩型矿床。     

中国豫西寒武系馒头组叠层石的沉积特征及其古环境意义

中国豫西寒武系馒头组一、二段共出露9层叠层石,占寒武纪18层叠层石中的50%,且其特征明显、形态多样,可分为圆柱状、波状、半球状和围绕竹叶状砾屑灰岩生长的叠层石等4大类8小类。本文在逐层分析豫西寒武系馒头组一、二段叠层石相序特征的基础上,通过对不同类型叠层石的宏观、中观形态特征及伴生的其它沉积特征进行详细描述,并以巴哈马Highborne Cays现代海相叠层石的生长环境和前寒武纪叠层石的沉积环境等为佐证,建立了豫西寒武系馒头组8小类11种不同叠层石的沉积环境分布模式,其中潮上带以近水平状叠层石为主,少量为缓波状、小柱状和含水平状薄泥层的叠层石;潮间带上部以缓波状、小柱状和含水平状薄泥层的叠层石为主,少量锥柱状叠层石;潮间带中部以圆柱状叠层石为主,含扁平状核形石和竹叶状砾屑,少量为锥柱状和围绕竹叶状砾屑生长的叠层石;潮间带下部至潮下带以含圆形核形石的圆柱状和半球状叠层石为主,少量含核形石的倒锥状叠层石。海平面的变化即水动力条件是叠层石生长类型变化的决定因素。     

基于多源空间数据的淮河流域洪涝灾害监测评估

提出了综合利用被动微波卫星、中等空间分辨率光学卫星、高空间分辨率光学卫星和雷达卫星等遥感数据,地理数据,以及水文和气象等多源空间数据的洪涝灾害监测评估方法。并以2007年淮河流域洪涝灾害监测为例,快速获取了全流域洪涝灾害的时空变化特征信息,以及淮河干流区域的最大淹没面积及淹没历时数据,实现了重点区域灾情的精细监测和量化评估。结果表明,该方法充分利用多源空间数据,保证下垫面洪涝灾情信息的及时获取,克服了传统调查统计方法的不足,在2007年淮河流域防洪减灾服务中发挥了重要作用。     

基于新型能量插值法精确建立GRACE-only地球重力场模型

本文基于新型能量插值法,利用美国喷气推进实验室(JPL)公布的2008年的GRACE-Level-1B实测数据,反演了120阶GRACE地球重力场.首先,由于GPS轨道测量精度相对较低,通过将K波段测距仪高精度的星间距离观测量插值引入双星动能差中,进而建立了新型能量插值卫星观测方程.其次,详细对比分析了2点、4点、6点和8点能量插值观测方程对地球重力场反演精度的影响.研究结果表明:基于最优的信噪比,6点能量插值公式有利于提高120阶GRACE地球重力场的反演精度.最后,基于美国、欧洲和澳大利亚的GPS/水准观测数据检验了本文新建立的WHIGG-GEGM03S地球重力场模型的正确性和有效性.