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

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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,{3. 2Graduate University of chinese academy of sciences, Beijing 100049,{3. 3.epartment of Atmospheric science, Sun Yat-Sen University, Guangzhou 510275,{3. 4National Climate center,{3. Meteorological Administration, Beijing 100080,{3. 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 >3.°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

Prediction model for spring dust weather frequency in North china

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science china Earth sciences 2008年第5期51卷 709-720页

作者： LANG XianMei center for Disastrous Climate Research and Prediction, Institute of Atmospheric physics, chinese academy of sciences, Beijing 100029,{3. center for Disastrous Climate Research and Prediction Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

It is of great social and scientific importance and also very difficult to make reliable prediction for dust weather frequency (DWF) in North china. In this paper, the correlation between spring DWF in Beijing and Tianjin observation stations, taken as examples in North china, and seasonally averaged surface air temperature, precipitation, Arctic Oscillation, Antarctic Oscillation, South Oscillation, near surface meridional wind and Eurasian westerly index is respectively calculated so as to construct a prediction model for spring DWF in North china by using these climatic factors. Two prediction models, i.e. model-I and model-II, are then set up respectively based on observed climate data and the 3.-year (1970 -2001) extra-seasonal hindcast experiment data as reproduced by the nine-level Atmospheric General Circulation Model developed at the Institute of Atmospheric {3. (IAP9L-AGCM). It is indicated that the correlation coefficient between the observed and predicted DWF reaches 0.93. in the model-I, suggesting a high prediction skill one season ahead. The corresponding value is high up to 0.948 for the subsequent model-II, which involves synchronous spring climate data reproduced by the IAP9L-AGCM relative to the model-I. The model-II can not only make more precise prediction but also can bring forward the lead time of real-time prediction from the model-I’s one season to half year. At last, the real-time predictability of the two models is evaluated. It follows that both the models display high prediction skill for both the interannual variation and linear trend of spring DWF in North china, and each is also featured by different advantages. As for the model-II, the prediction skill is much higher than that of original approach by use of the IAP9L-AGCM alone. Therefore, the prediction idea put forward here should be popularized in other regions in china where dust weather occurs frequently.

关键词： spring dust weather frequency prediction model iap9l-agcm hindcast experiment real-time prediction

Fluorescence dynamics of interactions between polyamide PyPyPyβDp and DNA

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science china Chemistry 2006年第1期49卷 75-80页

作者： ZHANG Huijuan1,2, WANG Jin3. WU Yishi1, YUAN Gu3. AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, chinese academy of sciences, Beijing 100080, china 2. School of Life science and Technology, Beijing Institute of Technology, Beijing 100081, china 3. College of Chemistry and Molecular Engineering, Peking University, Beijing 100080, china 4. center for Condensed Matter physics, Institute of physics, chinese academy of sciences, Beijing 100080, china Correspondence should be addressed to Ai Xicheng and Zhang Jianping 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. School of Life science and Technology Beijing Institute of Technology Beijing 100081 China 3. College of Chemistry and Molecular Engineering Peking University Beijing 100080 China 4. center for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The photophysical properties of the polyamide PyPyPyβDp (PPP) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of PPP are very sensitive to solvents. In TKMC buffer PPP exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity PPP showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 3. ps for PPP, which verified that PPP bound into the minor groove of DNA duplex.

关键词： polyamide (PPP), calf thymus DNA (ctDNA), time-resolved fluorescence spectroscopy, recognition dynamics.

Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

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science china Earth sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2 & LI YaoKun3.4 1National Marine Environmental Forecasting center, Beijing 100081, china 2First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, china 3.tate Key Laboratory of Numerical Modeling for Atmospheric {3. and Geophysical Fluid Dynamics, Institute of Atmospheric physics, chinese academy of sciences, Beijing 100029, china 4Graduate University of chinese academy of sciences, Beijing 100049, china 1. National Marine Environmental Forecasting center Beijing 100081 China2. First Institute of Oceanography State Oceanic Administration Qingdao 266061 China3. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China4. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

Simulation of freezing and melting of soil on the northeast Tibetan Plateau

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chinese science Bulletin 2011年第20期56卷 2145-2155页

作者： XIA Kun 1,2,3.LUO Yong 2,4,5 & LI WeiPing 2 1 Institute of Atmospheric physics,chinese academy of {3.,Beijing 100029,china 2National Climate center,china Meteorological Administration,Beijing 100081,china 3.raduate University of chinese academy of sciences,Beijing 100049,china 4 center for Earth System science,Tsinghua University,Beijing 100084,china 5Key Laboratory of Earth System Numerical Simulation,Ministry of Education,Beijing 100084,china Institute of Atmospheric physics Chinese Academy of Sciences National Climate center China Meteorological Administration Graduate University of chinese academy of sciences center for Earth System science Tsinghua University Key Laboratory of Earth

Using observational data spanning the period from February to December 2009 and recorded at the Suli station in Qinghai Province,the land-surface model CLM3.0 was employed to simulate the freezing and melting of *** results indicate that the simulated soil temperature is higher than the observed soil temperature and the ultimate thawing date is earlier than the observed date during the melting *** the freezing period,the simulated soil temperature is lower than the observed soil temperature and the ultimate freezing of the deep soil is earlier than that ***,the simulation of freezing is better than that of melting,and the simulation of a shallow layer is better than that of a deeper *** the original CLM3.0,it is assumed that frozen soil begins to melt when the soil temperature exceeds 0C,which is inconsistent with *** critical freeze-thaw temperature was calculated according to thermodynamics equations and the freeze-thaw condition was *** this work,the melting rate for frozen soil was reduced using the modified scheme,and the simulated soil temperature was lowered. Meanwhile,the refreezing of soil during the melting season was well simulated and more closely matched ***,it was found that the rates of melting and freezing differ,with the former being slower than the latter,but refreezing during the melting season is rather quick.

关键词：土壤温度冻结期青藏高原东北部模拟融化观测数据热力学方程表面模型

Sea surface temperature east of Australia:A predictor of tropical cyclone frequency over the western North Pacific?

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chinese science Bulletin 2011年第2期56卷 196-201页

作者： ZHOU BoTao 1,2 & CUI Xuan 3.1 National Climate center,china Meteorological Administration,Beijing 100081,china 2 Nansen-Zhu International Research center,Institute of Atmospheric physics,chinese academy of sciences,Beijing 100029,china 3.National Meteorological center,china Meteorological Administration,Beijing 100081,china National Climate center China Meteorological Administration Beijing China Nansen-Zhu International Research center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China National Meteorological center China Meteorological Administration Beijing China

The relationship between sea surface temperature (SST) east of Australia and tropical cyclone frequency over the western North Pacific (WNPTCF) is analyzed by use of observation *** WNPTCF from June to October is correlated negatively to spring SST east of *** the spring SST is in the positive phase,a cyclonic circulation anomaly in the upper troposphere and an anticyclonic circulation anomaly in the lower troposphere prevail over the western North Pacific from June to October,concurrent with an anomalous atmospheric subsidence and an enlarged vertical zonal wind *** conditions are unfavorable for tropical cyclone genesis,and thus WNPTCF *** negative phase of the spring SST east of Australia leads to more tropical cyclones over the western North *** spring SST east of Australia may give rise to simultaneous change in tropical atmospheric circulation via the teleconnection wave train,and then subsequently affect atmospheric circulation variation over the western North Pacific.

关键词：热带气旋北太平洋澳大利亚西部海面温度热带大气环流预测频率

Effects of gravity waves on the distributions of O_3.and OH in the mesopause region

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chinese science Bulletin 2001年第15期46卷 1265-1268页

作者： XU Jiyao & MA RuipingLaboratory for Space Weather, center for Space science and Applied Research, chinese academy of sciences, Beijing 100080,{3. Laboratory of Numeric Study of Heliospheric physics, chinese academy of sciences, Beijing 100080,{3. Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Laboratory of Numeric Study of Heliospheric physics Chinese Academy of Sciences Beijing China

A dynamical-photochemical model of atmospheric gravity waves is used to study the influences of gravity waves on distributions of atmospheric minor species through transportation and photochemical reactions. We mainly study the effect of gravity waves on the distributions of atmospheric trace gases through the nonlinear photochemical reactions. O3.and OH are taken as examples in this note. The calculations indicate that the effect of gravity waves on the distributions of atmospheric trace gases is mainly through the nonlinear photochemical reactions in the mesopause region. The contribution of the nonlinear photochemical reaction caused by gravity waves can exceed the nonlinear transportation and the eddy diffusion.

关键词： gravity wave photochemical reaction coupling between photochemistry and dynamics.

A theoretical analysis of optical-to-THz conversion efficiency via optical rectification

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science china(Technological sciences) 2008年第12期51卷 2080-2088页

作者： LI DeHua1,QI XiaoDong2 & LIU ShengGang3.1 Terahertz Institute of Shandong University of science & Technology,Qingdao 266510,china 2 Changchun Institute of Optics,Fine Mechanics and physics,{3. academy of sciences,Changchun 13.03.,china 3.Terahertz research center,Physical Electronics College,University of Electronics science,Chengdu 610054,china Terahertz Institute of Shandong University of science & Technology Qingdao 266510 China Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China Terahertz research center Physical Electronics College University of Electronics Science Chengdu 610054 China

A theoretical analysis of an ultra-short pulse converted to Terahertz radiation via optical rectification in nonlinear optical crystal is presented here;several factors that affect optical-to-THz conversion efficiencies are discussed;pulse durations affect the conversion efficiency effectively:when crystal length is equal to the optimal crystal length lc,optical-to-THz conversion efficiency is the highest,but for the periodically-inverted electro-optic crystals,conversion efficiency is almost proportional to the crystal length when absorption can be *** account of the absorption of crystals,effective length of crystal is Leff=0.63.α,there is no apparent increase of conversion efficiency and the conversion efficiency approaches to a constant eventually when the crystal length is increased.

关键词： optical rectification periodically inverted effective length conversion efficiency

The size effect on transport properties of colossal magnetoresistance materials La_(0.67)Ca_(0.3.)MnO_3

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science china(physics,Mechanics & Astronomy) 2008年第3期51卷 251-257页

作者： LI PeiGang1,2,LEI Ming1,2,GUO YanFeng2,GUO Xi2,CHEN LeiMing2, TANG WeiHua1,2,SONG PengYun3.& CHEN JinPing3.1 Department of physics,center for Optoelectronics Materials and Devices,Zhejiang Sci-Tech University,Hangzhou 3.0018,china 2 National Laboratory for Condensed Matter physics,Institute of physics,chinese academy of sciences,Beijing 100080,china 3.Department of physics,Peking University,Beijing 100875,china 1. Department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou 310018 China 2. National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 3. Department of physics Peking University Beijing 100875 China

High quality La0.67Ca0.3.MnO3.(LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO3.100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2 and 1.5 μm,the insulator-to-metal transition temperature (TP) keeps un-changed compared with the film. For the micro-bridges with width of 1 μm,the TP shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm,the insulator-to-metal transition disappears. The magnetoresistance be-havior of these micro-bridges was studied,and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced.

关键词： colossal magnetoresistance pulsed electron deposition electron beam lithography electrical transport properties