检索结果-南通市图书馆

The onset and advance of the Asian summer monsoon

Science Bulletin 2006年第1期51卷 80-88页

作者： Lü Junmei1,2,4, ZHANG Qingyun1, TAO Shiyan1 & JU Jianhua3 1. State Key Laboratory of Numerical Modeling for Atmospheric Sci- ences and Geophysical Fluid Dynamics, institute of Atmospheric Physics, chinese Academy of sciences, beijing 100029, china 2. Department of Atmospheric sciences, Yunnan University, Kunming 650091, china 3. china Meteorological Administration Training Centre, beijing 100081, china 4. Graduate School of chinese Academy of sciences, beijing 100039, china State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Department of Atmospheric sciences Yunnan University Kunming 650091 China Graduate School of chinese Academy of sciences Beijing 100039 China china Meteorological Administration Training Centre Beijing 100081 China

Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the National Centers for Environmental Prediction/National Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South china Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2nd pentad of May.

关键词： Asian summer monsoon intraseasonal variability onset advance.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nontrivial homoclinic orbits for second-order singular and periodic Hamiltonian systems

引用

chinese Science Bulletin 1999年第2期44卷 123-129页

作者： LI Chengyue , FAN Tianyou TONG MingshengResearch Center of Materials Science, beijing institute of Technology, beijing 100081, china Department of Mathematics, Central University for Nationalities, beijing 100081, china Computer Center, beijing institute of Technology, beijing 100081, china Research Center of Materials Science Beijing Institute of Technology Beijing China Department of Mathematics Central University for Nationalities Beijing China Computer Center Beijing Institute of Technology Beijing China

The existence of nontrivial homoclinic orbits of periodic Hamiltonian systems: is proved, where q=（q1,q2,’',qn）, n>2; V（t, q）:R1×Rn\{e}→R1 is a potential With a singularity, i.e. -V（t, q）→+∞, as q→e. The m... 详细信息

关键词： Hamiltonian systems strong force condition homoclinic orbit.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigation on the skewness for independent component analysis

引用

Science china(Information sciences) 2011年第4期54卷 849-860页

作者： LIU ZhiYong & QIAO Hong institute of Automation,chinese Academy of sciences,beijing 100190,china 1. institute of Automation Chinese Academy of Sciences Beijing 100190 China

Skewness has received much less attention than kurtosis in the independent component analysis (ICA).In particular,the skewness seems to become a useless statistics after the kurtosis related one-bit-matching theorem was ***,as the non-Gaussianity of one signal comes mainly from skewness,it is intuitively understandable that its recovery should not rely on *** this paper we discuss the skewness based ICA,and show that any probability density function (pdf) with non-zero skewness can be employed by ICA for the recovery of the source with non-zero skewness,without needing to consider the skewness *** observation together with the one-bit-matching theorem provides a basic guideline for the model pdf design in ICA algorithm.

关键词： independent component analysis skewness kurtosis one-bit-matching theorem

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Water-vapor source shift of Xinjiang region during the recent twenty years

引用

Progress in Natural Science:Materials International 2007年第5期17卷 569-575页

作者： Dai Xingang , Li Weijing , Ma Zhuguo and Wang Ping (Key Laboratory of Regional Climate-Environment for Temperate East Asia, institute of Atmospheric Physics, chinese Academy of sciences, beijing 100029, china Laboratory for Climate Change, chinese Meteorological Administration, beijing 100081, china) [a]Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences Beijing China [b]Laboratory for Climate Change chinese Meteorological Administration Beijing China

The aim of this paper is to investigate the climate water-vapor sources of Xinjiang region and their shifts during the past 20 years. First, the principle and steps are roughly regulated to seek the water-vapor sources. Second, the climate stationary water-vapor transport in troposphere is calculated to distinguish where the water vapor comes from by ERA-40 reanalysis. In addition, the collocation between the transport and the atmospheric column water vapor content is analyzed. The results show that the major vapor comes from the west side of Xinjiang for mid-month of seasons, apart from July while the water vapor comes from the north or northwest direction. The water vapor sources are different for different seasons, for example, the Caspian Sea and Mediterranean are the sources in January and April, the North Atlantic and the Arctic sea in July, and the Black Sea and Caspian Sea in October, respectively. In recent ten years more water vapor above Xinjiang comes from the high latitudes and the Arctic sea with global warming, and less from Mediterranean in comparison with the case of 1973—1986. In fact, the air over subtropics becomes dry and the anomalous water vapor transport direction turns to west or southwest during 1987—2000. By contrast, the air over middle and high latitudes is warmer and wetter than 14 years ago.

关键词： global warming water-vapor source water-vapor transport precipitable water Xinjiang climate inter-decadal change.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Low-frequency variability of the North Equatorial Current bifurcation in the past 40 years from SODA

引用

Acta Oceanologica Sinica 2011年第3期30卷 14-19页

作者： MENG Qingji WANG Fan LIU Na Key Laboratory of Ocean Circulation and Waves （KLOCAW） Chinese Academy of Sciences Qingdao 266071 China Graduate School of chinese Academy of sciences Beijing 100039 China National Marine Environmental Forecasting Center Beijing 100081 China

The low-frequency variability of the North Equatorial Current （NEC） bifurcation during 1958 to 2001 was investigated with the Simple Ocean Data Assimilation （SODA） 2.0.2 dataset. In agreement with recent observations, the NEC bifurcation latitude （NBL） shifted northward as depth increases, from about 12.7°N near the surface to about 17.1°N at depths around 500 m for the annual average. This study reveals that the interannual variations of NBL, with five years period, mainly focused on the upper 500 m with amplitude increasing as depth increased. The NBL shifted southward in the past 40 years, which was more significant in the subsurface at more than -0.02°/a. The NBL manifests itself in the transports of NMK （NEC-Mindanao Current （MC）-Kuroshio） system in strong relationship with MC （0.7） and Kuroshio （-0.7）. The EOF analysis of meridional velocity off the Philippine coast shows that the first mode, explaining 62% of variance and 5 years period, was highly correlated with the southward shift of NBL with coefficient at about 0.75. The southward shift of NBL consists with the weakening of MC and strengthening of Kuroshio, which exhibited linear trends at -0.24Sv/a and 0.11Sv/a. Both interannual variation and trend of NBL were closely related to the variation of NMK system.

关键词： North Equatorial Current bifurcation latitude interannual variation linear trend NEC-Mindanao Current-Kuroshio system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling the impact of Australian Plate drift on Southern Hemisphere climate and environment

引用

chinese Science Bulletin 2005年第14期50卷 1495-1502页

作者： ZHOU Botao1,5, ZHAO Ping2, JIAN Zhimin3 & HE Jinhai4 1. Nansen-Zhu International Research Center, institute of Atmospheric Physics, chinese Academy of sciences, beijing 100029, china 2. institute of Climate and Environment, chinese Academy of Meteoro- logical sciences, beijing 100081, china 3. Laboratory of Marine Geology, Tongji University, Shanghai 200092, china 4. Department of Atmospheric sciences, Nanjing institute of Meteorol- ogy, Nanjing 210044, china 5. Graduate School of the chinese Academy of sciences, beijing 100039, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of the chinese Academy of sciences Beijing 100039 China institute of Climate and Environment Chinese Academy of Meteorological Sciences Beijing 100081 China Laboratory of Marine Geology Tongji University Shanghai 200092 China Department of Atmospheric sciences Nanjing Institute of Meteorology Nanjing 210044 China

Using a global atmosphere-ocean coupled model with the present-day and 14 MaB.P. oceanic topogra- phy respectively, two experiments are implemented to inves- tigate the effect of different locations of Australian Plate on the atmospheric circulation in middle-high latitudes of the Southern Hemisphere. The results show that when Austra- lian Plate lay south at 14 MaB.P., both anticyclone circula- tions in the subtropical oceans and cyclone circulation around 60°-70°S are strengthened. Subtropical highs and circumpolar low pressure appear stronger, which results in much stronger Antarctic Oscillation and shorter period of Antarctic Oscillation Index (AOI) at 14 MaB.P. The rainfall and the surface air temperature also change correspondingly. The precipitation decreases around 40°S and increases around 60°-70°S, and the surface air temperature rises in high latitudes of the South Pacific and descends over the Weddell Sea and its north side. Besides, due to the changes of the temperatures and winds, Antarctic sea ice coverage also changes with its increasing in the Ross Sea and its west re- gions and decreasing in the Weddell Sea.

关键词：半球气候地球环球澳大利亚漂流物海洋地形学

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Anti-saturation block adaptive quantization algorithm for SAR raw data compression over the whole set of saturation degrees

引用

Progress in Natural Science:Materials International 2009年第8期19卷 1003-1009页

作者： Haiming Qi , Weidong Yu institute of Electronics, chinese Academy of sciences, beijing 100190, china [a]institute of Electronics Chinese Academy of Sciences Beijing 100190 China

In order to improve the performance of block adaptive quantization (BAQ) when the output of the analog to digital converter (ADC) is saturated, this paper proposes an anti-saturation BAQ algorithm. First, the concept of the standard deviation of the output signal (SDOS) of the ADC is proposed. Also, unlike traditional normalization processing, SDOS is used and the mapping between SDOS and the average signal magnitude is deduced. Second, the saturation term is introduced to the Lloyd–Max quantizer and an optimal non-uniform scalar quantizer for saturated SAR raw data quantization is proposed. After this, the implementation scheme for the proposed algorithm using an FPGA is analyzed in detail. Third, the relationships among the saturation degree of the signal, the peak-topeak value of the ADC, standard deviation of the input and output signal of the ADC and the average signal magnitude are deduced. Based on these relationships, a power compensation decoder is designed for encoding. Numerical experiment results based on ERS-1 and the simulated data show that the performance of the proposed algorithm is better than that of BAQ.

关键词： Synthetic aperture radar (SAR) Raw data compression Block adaptive quantization (BAQ) Anti-saturation

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Simulation of the future change of East Asian monsoon climate using the IPCC SRES A2 and B2 scenarios

引用

chinese Science Bulletin 2003年第10期48卷 1024-1030页

作者： BUEH Cholaw LASG, institute of Atmospheric Physics, chinese Academy of sciences, beijing 100029, china LASG Institute of Atmospheric Physics Chinese Academy of Sciences China

In this paper, we applied the newest emission scenarios of the sulfur and greenhouse gases, i.e. Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 and B2 scenarios, to investigating the change of the East Asian climate in the last three decades of the 21st century with an atmosphere-ocean coupled general circulation model. The global warming enlarges the land-sea thermal contrast and, hence, enhances (reduces) the East Asian summer (winter) monsoon circulation. The precipitation from the Yangtze and Huaihe river valley to North china increases significantly. In particular, the strong rainfall increase over North china implies that the East Asian rainy area would expand northward. In addition, from the southeastern coastal area to North china, the rainfall would increase significantly in September, implying that the rainy period of the East Asian monsoon would be prolonged about one month. In July, August and September, the interannual variability of the precipitation enhances evidently over North china, meaning a risk of flooding in the future.

关键词：模拟亚洲东方季风气侯变化大气循环模型

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Meteorological observations on Mount Everest in 2005

引用

Progress in Natural Science:Materials International 2007年第7期17卷 828-837页

作者： Xie Aihong~(1**) Qin Dahe~1 Ren Jiawen~1 Qin Xiang~1 Xiao Cunde~(1,2) Hou Shugui~1 Kang Shichang~(1,3) Yang Xingguo~(1,4) Jiang Youyan~1 (1.Key Laboratory of Cryosphere and Environment,Cold and Arid Regions Environment and Engineering Research institute,chinese Academy of sciences,Lanzhou 730000,china 2.chinese Academy of Meteorological Science,beijing 100081,china 3.institute of Tibetan Plateau Research,chinese Academy of sciences,beijing 100085,china 4.Gansu Provincial Meteorological Bureau,Lanzhou 730000,china) [a]Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environment and Engineering Research Institute Chinese Academy of Sciences Lanzhou China [b]chinese Academy of Metoorological Science Beijing China [c]institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China [d]Gansu Provincial Meteorological Bureau Lanzhou China

Mount Everest,the highest point on the Earth is often referred to as the earth's third pole as such the place is relatively inaccessible and little is known about its *** April 2005,an automatic weather station was installed at the mountain's North Col(6523 m a.s.l.).According to the observational 10-minute mean and daily records,the meteorological characteristics were analyzed. All the meteorological elements displayed obvious diurnal variations during May 1 to July 22,*** monthly variation of daily meteo- rological elements on Mount Everest coincided with that on Dingri,the closest routine meteorological station,with the high correlation co- efficients of 0.928,0.877,0.682,0.755,0.826 and 0.676(n=83,p485 and 0.487(n=83,p<0.001),*** other weather events on Mount Everest lagged one-day be- hind those on ***,forecasting of the weather events on Mount Everest from pressure on Dingri was more reliable than those from the other meteorological *** conclusions are much important for research on meteorology and climate changes in the region.

关键词： Mount Everest meteorological observation Dingri County radiation air temperature relative humidity air pressure wind

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Identification of novel SINEs from Cyprinidae and their evolutionary significance

引用

Progress in Natural Science:Materials International 2007年第3期17卷 270-279页

作者： HAN Yawei, HE Slumping and CHEN Yiyu ( institute of Hydrobiology, chinese Academy of sciences, Wuhan 430072, china. Graduate School, chinese Academy of sciences, beijing 100039, china) [a]institute of Hydrobiology Chinese Academy of Sciences Wuhan China [b]Graduate School Chinese Academy of Sciences Beijing China

Short interspersed nuclear elements (SINEs) are widespread among eukaryotic genomes. They are repetitive DNA sequences that have been amplified by retrotransposition. In this study, a class of SINEs were isolated from the Opsariichthys bidens genome, and named Opsar. Sequence analysis confirmed that Opsar is a new class of typical SINEs derived from tRNA molecules. With the tRNA-derived region of Opsar and through BLASTN search, we further identified Zb-SINEs from the zebrafish genome, which includes two groups: Zb-SINE-A and Zb-SINE-B. The Zb-SINE-A. group comprises subfamilies of -Al--A5, and the Zb-SINE-B group is a dimer of the tRNA -derived region and shares a similar dimeric composition to Alu. Zb-SINEs are composed of three distinct regions: a 5’ end tRNA-derived region, a tRNA-unrelated region and a 3’ end AT-rich region. The flanking regions are AT rich. The average length of Zb-SINEs elements is about 340 bp. Zb-SINEs account for as much as 0.1 % of the whole zebrafish genome. About 70% of the Zb-SINEs are on chromosomes 11, 18, and 19. These Zb-SINEs were characterized by PCR and dot hybridization. The distribution pattern of Zb-SINEs in genome strongly supports the master genes model. The tRNA-derived regions of Opsar and Zb-SINEs were compared with the tRNAAla gene, and they showed 76% similarity, indicating that Opsar and Zb-SINEs originated from an inactive tRNA sequence or a tRNA -like sequence. In view of the evolutionary status of zebrafish in the Cyprinidae, we deduced that Zb-SINEs were a very old class of interspersed sequences.

关键词： short interspersed nuclear elements (SINEs) master gene model Opsar Zb-SINEs and Cyprinidae.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：