台风登陆衰减后造成降水加强的概况   总被引：4，自引：3，他引：1  

姚丽娜  曾明剑  韩桂荣  韦晋  赵凯 《气象科学》2013,33(1):77-82

对1965-2008年101例登陆台风衰减后3d内仍存在较强降水的天气过程,运用客观分离方法及其改进方案,分离提取了台风降水(Tropical Cyclone Precipitation;TCP),结果表明:即使登陆台风衰减为热带低压或停编后,因台风系统的存在而产生高强度降水是一种普遍现象,仍旧是预报服务中需要高度关注的问题.采用气候趋势系数和功率谱等方法得到TCP及台风的气候特征:台风衰减点的位置分布具有很强的区域性,与南岭、武夷山脉的走势大致吻合;台风衰减后降水并非单纯性减少,随着时间的推移,空间分布具有向北、向西扩散的特点,特别是中纬度地区的江汉一江淮一带,仍然是防灾减灾的重点.对于衰减后降水反而加强的台风,防御重点可以有针对性地对登陆华南类和登陆华东类两类路径的台风展开.  相似文献   

Earth System Model FGOALS-s2: Coupling a dynamic global vegetation and terrestrial carbon model with the physical climate system model     

王军  包庆  刘屹岷  吴国雄  纪多颖 《大气科学进展》2013,30(6):1549-1559

Earth System Models （ESMs） are fundamental tools for understanding climate-carbon feedback. An ESM version of the Flexible Global Ocean-Atmosphere-Land System model （FGOALS） was recently developed within the IPCC AR5 Coupled Model Intercomparison Project Phase 5 （CMIP5） modeling framework, and we describe the development of this model through the coupling of a dynamic global vegetation and terrestrial carbon model with FGOALS-s2. The performance of the coupled model is evaluated as follows. The simulated global total terrestrial gross primary production （GPP） is 124.4 PgC yr-I and net pri- mary production （NPP） is 50.9 PgC yr-1. The entire terrestrial carbon pools contain about 2009.9 PgC, comprising 628.2 PgC and 1381.6 PgC in vegetation and soil pools, respectively. Spatially, in the tropics, the seasonal cycle of NPP and net ecosystem production （NEP） exhibits a dipole mode across the equator due to migration of the monsoon rainbelt, while the seasonal cycle is not so significant in Leaf Area Index （LAI）. In the subtropics, especially in the East Asian monsoon region, the seasonal cycle is obvious due to changes in temperature and precipitation from boreal winter to summer. Vegetation productivity in the northern mid-high latitudes is too low, possibly due to low soil moisture there. On the interannual timescale, the terrestrial ecosystem shows a strong response to ENSO. The model- simulated Nifio3.4 index and total terrestrial NEP are both characterized by a broad spectral peak in the range of 2-7 years. Further analysis indicates their correlation coefficient reaches -0.7 when NEP lags the Nifio3.4 index for about 1-2 months.  相似文献   

吉林省主汛期典型多雨年和少雨年成因对比分析     

纪玲玲  杨雪艳  张婷  姜红霞  马树庆 《气象与环境学报》2013,29(3):42-47

将1951-2011年吉林省主汛期降水量排名的前、后6位分别定义为多、少雨年,利用NCEP（2.5°×2.5°）再分析资料计算主汛期平均高度场、温度场、风场及比湿、涡度等物理量场;根据天气学原理和常规天气预报经验,对比分析主汛期典型多雨与少雨天气系统结构形态、分布位置、中心强度等特征。结果表明：500 hPa多雨年568等高线较少雨年平均偏南3个纬度,副热带高压588等高线较少雨年平均偏西7个经度偏北1个纬度;低层辐合高层辐散是多雨年的重要特征;850 hPa和700 hPa平均水汽含量多雨年明显多于少雨年;典型多雨年850 hPa风场贝加尔湖附近为单辐合中心,少雨年为双辐合中心。  相似文献   

A Research on the Imaging Strategy and Imaging Simulation of Toutatis in the Chang’e-2 Flyby Mission     

ZHAO Yu-hui  WANG Su  HU Shou-cun  JI Jiang-hui 《Chinese Astronomy and Astrophysics》2014

For the Chang’e-2 extended mission of asteroid exploration, the illumination conditions for imaging the asteroid Toutatis are calculated in this paper according to the orbital parameters of both the Chang’e-2 detector and the asteroid, as well as the incident angles of sunlight. On this basis, it is suggested to take photographs after flyby, and the orientation of the camera's optical axis in the coordinate system deflned by Earth's mean equator and equinox at J2000.0 is proposed to be (118.02°, 22.03°). Based on the shape model of Toutatis determined by the foreign radar data, the orientation of the asteroid in the inertial space is calculated at the rendezvous time. Using the Oren-Nayar diffuse-reflection model and the relative positions among the sun, the asteroid, and the detector, together with the cameras orientation, the imaging simulations are performed on the starry sky background respectively at the distances of 300 km, 500 km, and 1000 km from the asteroid after flyby. The results of simulations are verified further by the optical images of Toutatis obtained in the mission.  相似文献   

Tidal Evolution of the Kepler Candidate Two-planet Systems     

DONG Yao  JI Jiang-hui 《Chinese Astronomy and Astrophysics》2014

The tidal evolution of ten Kepler candidate two-planet systems is investigated by using the general secular perturbation theory, and then a general picture of tidal evolution for these systems is described. Taking the KOI 1239 system as an example, the tidal effect of the system is studied in detail, the results indicate that the dissipative term of the tidal effect causes the attenuation of planets’ orbital eccentricities, and it plays a dominant role in the process of orbital evolution, however, the conservative term of the tidal effect and the relativistic effect may damp the excitation of the eccentricity of the inner planet under the secular perturbation of the outer planet. In addition, the process of tidal evolution is also affected by both the initial eccentricity of the outer planet and the planet's tidal dissipation coeffcient. At the same time, the numerical simulation on the tidal evolution of the KOI 1239 system is also made, and the numerical results are consistent with those of general secular perturbation theory.  相似文献   

国家1∶50000地形数据库的数据设计与建库     

商瑶玲  王东华  吉建培  刘建军 《地理信息世界》2006,(4)

国家基础地理信息系统1∶50000数据库是构建数字中国空间地理框架的重要组成部分,1∶50000地形数据库作为1∶50000数据库的重要数据内容,是数据内容复杂、建设难度最大的数据库。本文介绍了数据库在数据精度、数据质量和数据结构等方面的设计要求,同时对数据库建设的关键技术环节进行了介绍。  相似文献   

An Accessible Model of Dynamics and Cycle for Interstellar OH and H2O Maser Associations     

Hanping Liu  Jin Sun  T. Thissen 《Astrophysics and Space Science》2004,289(1-2):147-160

An accessible model for interstellar OH/H₂O maser associations is presented. It can be classified into radiative pumping model. It can close the dynamical cycle of H₂O and OH species, and can give an interpretation on interstellar OH/H₂O associations. A reasonable scheme for both regeneration and destruction of interstellar H₂O and OH molecules is argued. Our model has overcome the defects of former radiative models, and is compatible with astronomical conditions. It is shown that the rotational population of H₂O and OH in these regions is much less affected by collisions than by radiation. Some experiments have confirmed our proposal.  相似文献   

Cultivation of marine sponges   总被引：3，自引：0，他引：3  

曲翊 张卫李华  虞星炬 《中国海洋湖沼学报》2005,23(2):194-198

Sponges are the most primitive of multicellular animals, and are major pharmaceutical sources of marine secondary metabolites. A wide variety of new compounds have been isolated from sponges. In order to produce sufficient amounts of the compounds of the needed, it is necessary to obtain large amount of sponges.The production of sponge biomass has become a focus of marine biotechnology.  相似文献   

卫星数字图象处理与制图分析——以京津及邻区1:25万影象图的处理分析为例     

张晋  傅肃性  王恩尧 《地理研究》1987,6(2):14-20

利用计算机进行图象处理和彩色制印,编制了京津及邻区1:25万影象图。采用经数字处理的图象和制图分析等编改工艺,取得了高质量低成本的效果。  相似文献   

REDUCED GROWTH IN HYBRID TILAPIA (OREOCHROMIS MOSSAMBICUS×O. NILOTICUS) AT INTERMEDIATE STOCKING DENSITY     

王岩  崔奕波  杨云霞  蔡发盛 《中国海洋湖沼学报》2002,20(4)

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