云南腾冲火山区地震/次声台阵建设

在中央级公益性科研院所基本科研业务专项《地震重点监视区地震与次声联合台阵探测对比试验》支持下,在云南腾冲火山区建设了一个由4个子台组成的三角形地震/次声台阵,首次将宽频带地震计及次声传感器联合部署在强地震活跃区及火山区。本文详细介绍了腾冲火山区地震/次声台阵的建设及其观测系统组成,特别是与次声观测有关的次声降噪滤波系统,并提出了下一步研究工作。     

Analysis of Digital Strong Motion Records of the M_S 8.0 Wenchuan Earthquake by the Network of Shaanxi Province

Records of the May 12,2008 MS8.0 Wenchuan,Sichuan,earthquake from 27 stations of Shaanxi Digital Strong Motion Network are processed and analyzed,including baseline adjustment of acceleration traces,filtering,and calculations of velocities,displacements and acceleration response spectra.The results show that direction energy radiation of the large earthquake and horizontal inhomogeneous medium along the wave traveling path might both have some effect on the scattering degree of the attenuation of PGAH,besides influence of local site conditions.For the same intensity,the ratios of PGA /PGV are commonly small,on average about 5,which indicates that long period components are rich in ground motion.Intensities for most sites of the stations are within Ⅴ～Ⅶ.The larger one among PGAE-W and PGAN-S is quite close to their PGAH,which is less than 10% in relative deviation.The dominated waves are surface waves.The thicker the soil overburden is,the stronger the surface wave will be and the longer the shaking will last.Local site conditions have strong effects on ground motion,especially those of thick sediment filled-in basins,as they can significantly amplify long-period components.     

A data assimilation-based method for optimizing parameterization schemes in a land surface process model

Optimizing the parameters of a land surface process model(LSPM) through data assimilation(DA) can not only improve and perfect the parameterization schemes in the LSPM through the physical mechanism, but also increase its regional adaptability and simulation capability. This has practical importance for improving simulation results and the climate-prediction capability of general circulation models(GCMs) and regional climate models(RCMs). This paper presents a DA-based method for optimizing the parameterization schemes in LSPMs. We optimize the unsaturated-soil water flow(Un SWF) model as an example by developing a soil-moisture assimilation scheme based on the Un SWF model and the extended Kalman filter(EKF) algorithm, and then combining them with the Variable Infiltration Capacity(VIC) model. Using a month as the assimilation window, we used the Shuffled Complex Evolution–University of Arizona(SCE-UA) algorithm to minimize the objective function through simulated and assimilated soil moisture, achieved the best fit with the given objective function measurement, and optimized the parameters of the Un SWF model, including the saturated-soil hydraulic conductivity, moisture content, matrix potential, and the Clapp and Hornberger constant. The optimal values of the model parameters were obtained during the DA period(the year 1986), and then the optimized parameters were used to improve the Un SWF model. Finally, numerical simulation experiments were carried out from 1986 to 1993 to evaluate the simulation capability of the improved model and to explore and realize the DA-based method for optimizing the soil water parameterization scheme in LSPMs. The experimental results indicated that the optimized model parameters improved and perfected the model based on the physical mechanism, and increased its simulation capability; the optimized model parameters had good temporal portability and their adaptability was stronger, achieving the aim of improving the model. Therefore, this method is reasonable and feasible. This paper provides a good reference for DA-based optimization of the parameterization schemes in LSPMs.     

利用古氧相和古生产力替代指标评价四川上寺剖面二叠系海相烃源岩

 中国具备良好的海相地层油气勘探前景,如何正确识别并合理评价海相烃源岩是中国海相盆地油 气勘探开发中亟待解决的关键问题。作者尝试利用多个微量元素分别作为古生产力和古氧相的综合替代指标, 来进行有效烃源岩评价。研究中利用四川广元上寺剖面二叠系中Mo,U ,V,Cu,Ni,Zn6个微量元素测试结 果,计算得到对应两组元素过剩值：Mo_xS ,U_XS ,v_xs 和Cu_xs,Ni_xs,Zn_xs;对这两组元素过剩值分别进行主成分分 析,得到两个系数- - -古生产力替代指标综合系数 （ 简称古生产力系数）和古氧相替代指标综合系数 （ 简称古 氧相系数） ,用以恢复海相烃源岩的古生产力和古氧相条件;将该系数与上寺剖面残余有机碳测试结果 （ THC含 量）进行相关性分析,依此确定古生产力和古氧相条件的定量等级划分。最终,根据该划分标准来判断上寺剖 面烃源岩的品质。利用古生产力和古氧相的综合替代指标方法可为海相烃源岩评价工作提供一些新思路。     

青藏块体东北缘潜在强震震源研究

依据单一力源模型的基本原理 ,利用青藏块体东北缘多年来水准观测垂直位移资料 ,反演该区 2 0a来中强地震的潜在震源力学参数与未来可能的危险区域 ,得到 :①如果确定所选研究区仅有一个等价强震力源 ,反演的强震力源与实际震中符合度较好 ,这对中强地震地点的预测有一定的参考价值 ;②在青藏块体东北缘6级左右的地震 ,比较合理的可研究范围一般为震源有效半径的 1 0倍 ,对应的等价力源的量级约为 1 0 1 1 N ;③从 1 995～ 2 0 0 0年的分区模拟结果看 ,在祁连的中段存在一个潜在的等价强震力源 (1× 1 0 1 1 N) ;另外 ,在青海与甘肃南部交界处存在一个潜在的等价强震力源 ,该力源深度为 5km ,大小达到 5× 1 0 1 1 N。     

Stability and long-range correlation of air temperature in the Heihe River Basin

Journal of Geographical Sciences - Air temperature (AT) is a subsystem of a complex climate. Long-range correlation (LRC) is an important feature of complexity. Our research attempt to evaluate...     

辽河干流上游流域土地利用对土壤颗粒分形维数影响

分析了辽河干流典型风沙区林地、草地和农田土壤颗粒的分形维数空间分布特征。结果表明：土壤颗粒分形维数总体表现为农田高于林地和草地,且在农田土壤30~50 cm深度时达到最大值（2.58）,在草地土壤0~10 cm出现最小值（2.26）;在林地土壤中随深度增加而减小,在草地和农田土壤中随深度增加而增加。土壤分形维数均与粉粒含量极显著正相关（P<0.01）。农田更有利于土壤细小颗粒的形成,改良土壤质地,土壤结构相对较好,其次是林地,草地相对较差。     

天空辐射计观测2006年春季北京地区气溶胶光学特性的研究

利用2006年3～5月天空辐射计观测数据反演得到北京地区春季大气气溶胶光学性质参数,包括大气气溶胶光学厚度(0.5μm)、Angstrm指数、单次散射反射比和粒子谱分布特征。结果表明:北京地区春季气溶胶平均光学厚度0.67,Angstrm指数0.54,单次散射比0.88,粒子吸收性质较弱,粒子谱呈双峰形,以粗粒子为主,粗、细模态粒子粒径分别集中在0.17μm和7.7μm左右。相比2004年此次观测期间气溶胶粒径较大,粒子体积浓度较高,散射作用在其消光特性中的比重略有下降。光学厚度日变化呈单峰型,日间单次散射比随时间逐渐递减,Angstrm指数在上午递减趋势明显,午后变得稳定。对同时观测的天空辐射计与CE-318不同波长光学厚度结果进行比较,结果显示两者得到的光学厚度相关性很好,各波长小时平均结果的相对误差小于7%。     

一次带有雷电现象的冬季雪暴中尺度探测分析

对2009年11月9日北京市一次伴随雷电的局地暴雪过程的中小尺度特征进行了分析。采用了风廓线雷达资料、微波辐射计资料、自动气象站资料、多普勒天气雷达资料和卫星资料,对此次降雪的精细时空结构进行了分析,通过天气尺度及中小尺度分析,探讨了冬季对流产生的原因。结果表明:此次过程为华北回流天气过程,西南暖湿空气在低层冷空气之上产生高架对流和雷电天气,对流的触发机制是中空扰动。     

地闪资料在LAPS云分析中的应用研究

为进一步研究闪电活动特征,利用ADTD闪电定位资料、静止气象卫星葵花八号等气象资料,对2016年7月20日一次强对流天气过程中的闪电活动进行分析,探讨闪电活动与LAPS云分析场的关系,探索地闪资料在LAPS云分析中的应用。结果表明,地闪活动集中区域对应着强降水区,降水峰值与闪电活动峰值为重合的现象;大部分闪电发生处于对流云系影响范围之内且对应了中高层次的云顶性质;在LAPS云分析场中地闪活动频繁的区域,云柱更为厚实且出现了更为强烈的上升运动,水汽也更为充沛,闪电活动与积雨云的对应关系不仅可以反向验证卫星反演的云分类产品,也可以对LAPS三维云场进行订正和调整,并作为多源数据融合云分析的补充资料。