检索结果-南通市图书馆

Abrupt climate change and collapse of ancient civilizations at 2200BC-2000BC

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第10期15卷 46-52页

作者： WANG Shaowu (department of atmospheric Science, School of Physics, Peking university, Beijing 100871, China) department of atmospheric Science School of Physics Peking University Beijing 100871 China

Plentiful evidence of historical, archaeological and palaeoclimatic studies proved that an abrupt change from wetter to drier climate occurred over the Nile Valley,the Mesopotamia, the Indus Valley and Huanghe River Valley at 2200BC-2000BC. The abrupt change was developed based on the general lowering of temperature in the middle latitudes, and was a strong cold event since the beginning of the Megathermal (8.5-3.0 kaBP). Collapse of Nile civilization appeared at the First Intermediate Period (2181BC-204.BC). Civilization of Mesopotamia began collapse following the disintegration of Akkadian Empire. This process lasted to the foundation of Babylon Kingdom from 2200BC to 1900BC. Indus civilization abruptly fell off at 1800BC. A widespread alternation of archaeological cultures happened in China at ca. 2000BC except only in its central part. Longsheng culture was replaced by the Erlitou culture, which is now acknowledged in China as Xia Culture. Foundation of Xia Dynasty at 2070BC opened a new chapter in the development of Chinese civilization. Studies indicated that abrupt climate change may be caused by the weakening of the Thermohaline Circulation (THC).

关键词： 2200BC-2000BC abrupt climate change collapse of ancient civilization.

Vortex genesis over the Bay of Bengal in spring and its role in the onset of the Asian Summer Monsoon

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth sciences 2011年第1期54卷 1-9页

作者： WU GuoXiong1, GUAN Yue1,2, WANG TongMei3, LIU YiMin1, YAN JingHui4.& MAO JiangYu1 1 State Key Laboratory of Numerical Modeling for atmospheric sciences and Geophysical Fluid Dynamics (LASG), Institute of atmospheric Physics, Chinese Academy of sciences, Beijing 100029, China 2Graduate {4. of Chinese Academy of sciences, Beijing 10004., China 3department of atmospheric Science, Sun Yat-Sen {4., Guangzhou 510275, China 4.ational Climate Center, China Meteorological Administration, Beijing 100080, China 1. State Key Laboratory of Numerical Modeling for atmospheric sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Department of Atmospheric Science Sun Yat-Sen University Guangzhou 510275 China4. National Climate Center China Meteorological Administration Beijing 100080 China

Physical processes associated with onset of the 1998 Asian summer monsoon were examined in detail using multi-source datasets. We demonstrated that strong ocean-atmosphere-land interaction in the northern Indian Ocean and tropical Asian area during spring is a fundamental factor that induces the genesis and development of a monsoon onset vortex over the Bay of Bengal (BOB), with the vortex in turn triggering onset of the Asian summer monsoon. In spring, strong surface sensible heating over India and the Indochina Peninsula is transferred to the atmosphere, forming prominent in situ cyclonic circulation, with anticyclonic circulations over the Arabian Sea and northern BOB where the ocean receives abundant solar radiation. The corresponding surface winds along the North Indian Ocean coastal areas cause the ocean to produce the in situ offshore currents and upwelling, resulting in sea surface temperature (SST) cooling. With precipitation on the Indochina Peninsula increasing from late April to early May, the offshore current disappears in the eastern BOB or develops into an onshore current, leading to SST increasing. A southwest-northeast oriented spring BOB warm pool with SST >31°C forms in a band from the southeastern Arabian Sea to the eastern BOB. In early May, the Somali cross-equatorial flow forms due to the meridional SST gradient between the two hemispheres, and surface sensible heat over the African land surface. The Somali flow overlaps in phase with the anticyclone over the northern Arabian Sea in the course of its inertial fluctuation along the equator. The convergent cold northerlies on the eastern side of the anticyclone cause the westerly in the inertial trough to increase rapidly, so that enhanced sensible heat is released from the sea surface into the atmosphere. The cyclonic vorticity forced by such sensible heating is superimposed on the inertial trough, leading to its further increase in vorticity strength. Since atmospheric inertial motion is destr

关键词： air-sea interaction spring BOB warm pool monsoon onset vortex inertial oscillation Asian summer monsoon onset

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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. {4. of atmospheric sciences, Nanjing Institute of Meteorol- ogy, Nanjing 21004., 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 4.°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

Design of a new dynamical core for global atmospheric models based on some efficient numerical methods

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2004年第z1期47卷 4-21页

作者： WANG Bin, WAN Hui, Jl Zhongzhen, ZHANG Xin, YU Rucong, YU Yongqiang & LIU HongtaoState Key Laboratory of Numerical Modeling for atmospheric sciences and Geophysical Fluid Dynamics, Institute of atmospheric Physics, Chinese Academy of sciences, Beijing 100029, China {4. of Computational Mathematics, Academy of Mathematics and System sciences, Peking university, Beijing 100871, China Chinese Acad Sci Inst Atmospher Phys State Key Lab Numer Modeling Atmospher Sci & Geop Beijing 100029 Peoples R China Peking Univ Acad Math & Syst Sci Dept Computat Math Beijing 100871 Peoples R China

A careful study on the integral properties of the primitive hydrostatic balance equations for baroclinic atmosphere is carried out, and a new scheme todesign the global adiabatic model of atmospheric dynamics ispresented. This scheme includes a method of weighted equal-areamesh and a fully discrete finite difference method with quadraticand linear conservations for solving the primitive equationsystem. Using this scheme, we established a new dynamical corewith adjustable high resolution acceptable to the availablecomputer capability, which can be very stable without anyfiltering and smoothing. Especially, some important integralproperties are kept unchanged, such as the anti-symmetries of thehorizontal advection operators and the vertical convectionoperator, the mass conservation, the effective energy conservationunder the standard stratification approximation, and so on. Somenumerical tests on the new dynamical core, respectively regardingits global conservations and its integrated performances inclimatic modeling, incorporated with the physical packagesfrom the Community atmospheric Model Version 2 (CAM2) of NationalCenter for atmospheric Research (NCAR), are included.

关键词： dynamical core, equal-area mesh, anti-symmetry, effective energy conservation.

THE PHASE RELATION BETWEEN ACCUMULATIVE EFFECT OF SOLAR ECLIPSE AND EL NINO

在线全文

学校读者我要写书评

暂无评论

南京大学学报(自然科学) 1999年第6期35卷 135-137页

作者： Lin Zhen Shan (department of atmospheric sciences, Nanjing university, 210093, Nanjing,PRC) 南京大学江苏南京 2 1 0 0 93

ＢｙａｎａｌｙｚｉｎｇａｌｌｔｈｅｄａｔａｏｆＥｌＮｉｎｏａｎｄｔｈｅｓｏｌａｒｅｃｌｉｐｓｅｓｆｒｏｍ194.ｔｏ1998,ｓｏｍｅｃｏｍｐｌｅｘｒｅｌａｔｉｏｎｓｂｅｔｗｅｅｎｔｈｅｓｏｌａｒｅｃｌｉｐｓｅｓａｎｄＥｌＮ... 详细信息

ＢｙａｎａｌｙｚｉｎｇａｌｌｔｈｅｄａｔａｏｆＥｌＮｉｎｏａｎｄｔｈｅｓｏｌａｒｅｃｌｉｐｓｅｓｆｒｏｍ194.ｔｏ1998,ｓｏｍｅｃｏｍｐｌｅｘｒｅｌａｔｉｏｎｓｂｅｔｗｅｅｎｔｈｅｓｏｌａｒｅｃｌｉｐｓｅｓａｎｄＥｌＮｉｎｏａｒｅｆｏｕｎｄａｓｆｏｌｌ?..

关键词： El Nino eclipse prediction

Annual precipitation fields secular variation over global land areas for 194.—2000

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第3期48卷 281-286页

作者： SHI Neng & CHEN Luweng department of atmospheric sciences, Nanjing Institute of Meteorology, Nanjing 21004., China department of atmospheric sciences Nanjing Institute of Meteorology Nanjing 210044 China

The secular variation over the global land an-nual precipitation (GLAP) fields for 194.—2000 is investi-gated. Evidence suggests that the GLAP abruptly reduced around 1978 and experienced a decrease of 0.54.mm/a, on average. Fuzzy clustering is used to group the annual pre-cipitation over commonly-used 36 latitudes belts into six belts for examining its secular variation. The results show that, except northern high-latitudes (60°—90°N) where it is slightly increased, the precipitation is decreased, especially in 35°N—35°S, and the diminution is the maximum of 0.98 mm/a at tropics. Moreover, identification of 194.—2000 flood/drought years on a global basis is made, showing no-ticeable interdecadal variations. During the years of warm (cold) events the precipitation decreases (increases) by 15.4.mm (14.4.mm) per year, on average. It can be assumed that global warming and frequent ENSO occurrences from the end of the 1970s maybe serve as the root cause of the dimi-nution.

关键词：全球降水长期变化年降水 ENSO 陆地 194.-2000年

Effects of salinity on methane gas hydrate system

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2007年第11期50卷 1733-1745页

作者： YANG DingHui1 & XU WenYue2 1 department of Mathematical sciences, Tsinghua university, Beijing 100084. China 2 School of Earth & atmospheric sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA 1. department of Mathematical sciences Tsinghua University Beijing 100084 China 2. School of Earth & atmospheric sciences Georgia Institute of Technology Atlanta GA 30332 USA

Using an approximately analytical formation, we extend the steady state model of the pure methane hydrate system to include the salinity based on the dynamic model of the methane hydrate system. The top and bottom boundaries of the methane hydrate stability zone (MHSZ) and the actual methane hy-drate zone (MHZ), and the top of free gas occurrence are determined by using numerical methods and the new steady state model developed in this paper. Numerical results show that the MHZ thickness becomes thinner with increasing the salinity, and the stability is lowered and the base of the MHSZ is shifted toward the seafloor in the presence of salts. As a result, the thickness of actual hydrate occur-rence becomes thinner compared with that of the pure water case. On the other hand, since lower solubility reduces the amount of gas needed to form methane hydrate, the existence of salts in sea-water can actually promote methane gas hydrate formation in the hydrate stability zone. Numerical modeling also demonstrates that for the salt-water case the presence of methane within the field of methane hydrate stability is not sufficient to ensure the occurrence of gas hydrate, which can only form when the methane concentration dissolved in solution with salts exceeds the local methane solubility in salt water and if the methane flux exceeds a critical value corresponding to the rate of diffusive methane transport. In order to maintain gas hydrate or to form methane gas hydrate in marine sedi-ments, a persistent supplied methane probably from biogenic or thermogenic processes, is required to overcome losses due to diffusion and advection.

关键词： methane gas hydrate,solubility,stability of hydrate,salinity,phase equilibrium

An OGCM Simulation of Seasonal and Interannual Variabilities in the Surface-Layer Pacific of the Equatorial Band

在线全文

学校读者我要写书评

暂无评论

Advances in atmospheric sciences 2002年第2期19卷 219-235页

作者： Boyin Huang and Zhengyu Liu department of atmospheric and Oceanic sciences, university of Wisconsin-Madison 1225 W. Dayton St., Madison, WI-53706, U.S.A. department of Earth Atmospheric and Planetary Sciences Massachusetts Institute of Technology Room 54-1721 77 Massachusetts Ave. 02139 Cambridge MA USA department of atmospheric and Oceanic sciences University of Wisconsin-Madison 1225 W. Dayton St. 53706 Madison WI USA

The heat budget is analyzed in the surface-layer (0-50 m) Pacific of the equatorial band (10°S-10°N), using the simulation of an ocean general circulation model from 194. to 1993. The analysis indicates that downward net surface heat flux from the atmosphere and ocean advective heat fluxes play distinct roles in seasonal and interannual variabilities of surface-layer ocean temperature. The surface heat flux dominantly determines the ocean temperature in the seasonal time-scale. But, it has a negative feedback to the ocean temperature in the interannual time-scale. The interannual variability of ocean temperature is largely associated with the cold advection from off-equatorial divergent flow in the central Pacific and from upwelling in the cold tongue. Both the surface heat flux and ocean advective heat fluxes are important to the ocean temperature during an El Nino event. The ocean. advective heat fluxes are further associated with local westward trade wind in the central Pacific. These results are largely consistent with some regional observational analyses.

关键词： Seasonal variability Interannual variability Heat flux

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第12期15卷 1110-1116页

作者： LIU Gang,LI Xin,JIANG Weimei and LI Min department of atmospheric sciences,Nanjing university,Nanjing 210093,China Beijing Municipal Environmental Protection Bureau,Beijing 10004.,China department of atmospheric sciences Nanjing University Nanjing 210093 China. Beijing Municipal Environmental Protection Bureau Beijing 100044 China

The S-L (She and Leveque) scaling law,also named the hierarchical similarity theory,has been extensively tested for the turbulence made in the laboratory,but seldom been tested for the turbulence in the atmospheric boundary layer (ABL).In this paper, the S-L scaling law is applied to the turbulence in the ABL observed under unstably stratified conditions and over different types of underlying *** results of analyses show that over this type of homogeneous and flat underlying surface,such as the underlying surface in HUBEX (Huaihe River Basin Energy and Water Cycle Experiment),vertical speed and temperature fields well satisfy the S-L scaling *** the turbulence over the homogeneous but rather rough underlying surface of forest and under unstably stratified conditions in PFRD (Park Falls Ranger District of the Chequamegon National Forest,Wisconsin,USA),the analyses show that the vertical speed and temperature fields sometimes conform sometimes do not conform to the S-L scaling ***,at a time,either both of the vertical speed and temperature fields conform to the S-L scaling law,or both of them do *** speed fields in both of the field experiments do not satisfy the S-L scaling *** new explanation of the above-mentioned phenomena is given.

关键词： atmospheric turbulence Reynolds number S-L scaling law in the atmospheric turbulence boundary layer processes nonlinear dynamics