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Numerical study of rapid cyclogenesis over sea

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Acta Oceanologica Sinica 1989年第1期8卷 51-62页

作者： Du Jun and Yu Zhihao department of atmospheric sciences, Nanjing university, Nanjing, China Dept. of atmospheric sciences Nanjing Univ Nanjing China. China

A five-layer primitive equation model was used in the study of rapid cyclogenesis over sea. The numerical simulations show that'the Tibetan Plateau, large-scale baroclinicity and heat flux from the sea surface are the three important agents to produce cyclonic vorticity along the east coast of China. The diagnostic computation of a 24.h control simulation indicates that the nonlinear vorticity advec-tion, baroclinicity and diabatic heating are also responsible for the development of the extratropical cyclones over seas.

关键词： Numerical study of rapid cyclogenesis over sea over

North Pacific sea ice cover, a predictor for the Western North Pacific typhoon frequency?

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Science China Earth sciences 2007年第8期50卷 1251-1257页

作者： FAN Ke Institute of atmospheric Physics, Chinese Academy of sciences, Beijing 100029, China department of atmospheric Science, Yun-nan {4., Kunming 650091, China 1. Institute of atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. department of atmospheric Science Yunnan University Kunming 650091 China

The relationship between the sea ice cover in the North Pacific and the typhoon frequency has been studied in this paper. It follows that the index for the sea ice cover in the North Pacific (ISA) both in December-January-February (DJF) and in March-April-May (MAM) is negatively correlated with annual typhoon number over the western North Pacific (TNWNP) during 1965―2004. with correlation coeffi-cients of -0.4. and -0.4. respectively (above 99% significant level). Large sea ice cover in the North Pacific tends to decrease TNWNP. Positive ISA (MAM) is associated with the tropical circulation and SST anomalies in the North Pacific, which may lead to unfavorable dynamic and thermal conditions for typhoon genesis over WNP from June to October (JJASO). The variability of the atmospheric circula-tion over the North Pacific, associated with the ISA anomaly in MAM is connected to the tropical at-mospheric circulation variability in MAM via the teleconnection wave train. Besides, as the tropical circulation has strong seasonal persistency from the MAM to JJASO, thus, the ISA in MAM-related variability of the tropical atmospheric circulation as well as the SST can affect the typhoon activity over the western North Pacific.

关键词： typhoon sea ice cover North Pacific teleconnection

The onset and advance of the Asian summer monsoon

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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.

Numerical simulation of influence of the anomalies of theCentral-eastern Equatorial Pacific SST and Arctic seaice cover in summer on the atmospheric circulation

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Acta Oceanologica Sinica 1992年第3期11卷 401-411页

作者： Yang Xiuqun and Huang Shisong department of atmospheric sciences, Nanjing university, Nanjing 210008, China

A series of numerical experiments have been conducted with a perpetual July, nine-level general circulation spectral model to determine the effect of variation of the Arctic sea ice cover extent and the joint effect of anomalies of both the Arctic sea ice cover and the Central-eastern Equatorial Pacific sea surface temperature on the summer general circulation. Results show that the two factors,anomalously large extent of the Arctic sea ice cover and anomalously warm sea surface temperature over the Central-eastern Equatorial Pacific Ocean, play substantially the equal role in the effect on the summer general circulation, and either of them can notably induce the atmospheric anomalies. The main dynamical processes determining the effect of the Arctic sea ice and the equatorial SST anomalies are associated with two leading teleconnection patterns, i. e. the Asia North/American and Eurasian patterns observed in atmosphere. The results presented in this paper again prove that the general circulation is fundamentally motivated by the non-uniform heating between the equator and the pole on the rotating earth.

关键词： Numerical simulation of influence of the anomalies of theCentral-eastern Equatorial Pacific SST and Arctic seaice cover in summer on the atmospheric circulation SST

Estimating surface evapotranspiration using combined MODIS and CBERS-02 data

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Science China(Technological sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2, LIU Qinhuo1, TANG Yong1,3, TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2, ZHENG Hongsheng4.& CHEN Jiayi4.1. State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of sciences, Beijing 100101, China 2. Research Center for Remote Sensing and GIS, department of Geography, Beijing Normal university, Beijing 100875, China 3. Graduate university of Chinese Academy of sciences, Beijing 100039, China 4. department of atmospheric Physics, Peking university, Beijing 100871, China 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02 data were used to produce land use class of Baiyangdian area, Hebei Province, China in the autumn of 2004. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

Debating about the climate warming

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Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2, ZHAO Zongci2, DONG Wenje2 and YANG Bao3 (1.department of atmospheric sciences, School of Physics, Peking university, Beijing 100871, China 2. Laboratory for Climate Studies, China Meteorological Administration, Beijing 100081, China 3. Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of sciences, lanzhou 730000, China) [a] department of atmospheric sciences School of Physics Peking University Beijing China [b] Laboratory for Climate Studies China Meterological Administration Beijing China [c] Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2) All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3) The warming from 1975 to 2000 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 20th century.

A study on dynamical features of air-sea coupling waves in the tropics

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Acta Oceanologica Sinica 1993年第3期12卷 379-393页

作者： Yang Xiuqun and Huang Shisong department of atmospheric sciences, Nanjing university, Nanjing 210008, China

The dynamical features of air-sea coupling waves and their stabilities in a simple coupled air-sea model in the tropics have been studied with respect to interaction occurring among different types of the free waves in the o-cean and in the atmosphere. It is pointed out that there exist a stable and an unstable air-sea interaction modes in the tropical coupled system , respectively. The propagation of the unstable mode relies greatly on the zonal space scale, i. e. only for wave length ranging from 5 000 km to 10 000 km can the disturbance unstably move slowly eastward. The waves that slowly propagate unstably eastward agree well with the observational facts. Finally,it is also proposed that the interaction between Kelvin wave in one medium and Rossby wave in another medium is a necessary condition for the occurrence of destabilization of the coupled air-sea system in the tropics.

关键词： Air-sea interaction coupling waves features

A quasi-geostrophic wavelet-spectrum model for barotropic atmosphere and its numerical solution

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Progress in Natural Science:Materials International 2004年第11期 48-54页

作者： DAI Xingang 1,2*, WANG Ping 3 and CHOU Jifan 2 (1. Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of atmospheric Physics, Chinese Academy of sciences, START Regional Center for Temperate East Asia, Beijing 100029, China 2. department of atmospheric sciences, lanzhou university, lanzhou 730000, China 3. College of Physics, Peking university, Beijing 100871, China) KeyLaboratoryofRegionalClimate-EnvironmentforTemperateEastAsia InstituteofAtmosphericPhysicsChineseAcademyofSciencesSTARTRegionalCenterforTemperateEastAsiaBeijing100029China CollegeofPhysics PekingUniversity.Beijing100871China departmentofatmosphericsciences LanzhouUniversityLanzhou730000.China

A quasi-geostrophic wavelet-spectrum model of barotropic atmosphere has been constructed by wavelet-Galerkin method with the periodic orthogonal wavelet bases. In this study a wavelet grid-spectrum transform method is designed to decrease the tremendous computation of the nonlinear interaction term in the model, and a two-dimensional Helmholtz equation from the model in a wavelet spectrum form is derived, and a solution with high precision under the periodic boundary condition is obtained. The numerical investigation manifests that the wavelet-spectrum model (WSM) could keep on running for a long time under the forcing of heating and topography. Although its numerical solution is compatible with the grid model (GM), the WSM is of a higher precision and faster convergence rate than GM's. A stationary solution comes forth when the model is forced only by the surface heating, whereas a quasi-periodic oscillation with a period about 15 days appears as considering the topography in the model. The latter oscillation, to some extent, is very similar to the Rossby index cycle of atmosphere over middle and high latitudes.

关键词： plane barotropic atmosphere wavelet-spectrum model wavelet grid-spectrum transform.

Application of long-range correlation and multi-fractal analysis for the depiction of drought risk

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Chinese Physics B 2016年第1期25卷 831-837页

作者：侯威颜鹏程李淑萍涂刚胡经国 National Climate Center Beijing 100081China College of atmospheric sciences Lanzhou UniversityLanzhou 730000China Jilin Meteorological Science Institute Changchun 130062China department of Physics Yangzhou university Yangzhou 225002China

By using the multi-fractal detrended fluctuation analysis method, we analyze the nonlinear property of drought in southwestern China. The results indicate that the occurrence of drought in southwestern China is multi-fractal and long- range correlated, and these properties are indifferent to timescales. A power-law decay distribution well describes the return interval of drought events and the auto-correlation. Furthermore, a drought risk exponent based on the multi-fractal property and the long-range correlation is presented. This risk exponent can give useful information about whether the drought may or may not occur in future, and provide a guidance function for preventing disasters and reducing damage.

关键词： multi-fractal detrended fluctuation analysis return intervals drought risk