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Computational stability of the forced dissipative nonlinear atmospheric equations

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Chinese Science Bulletin 1999年第10期44卷 949-952页

作者： LI Jianping and CHOU Jifan LASG , Institute of atmospheric Physics , Chinese Academy of sciences , Beijing 100080, china department of atmospheric sciences , lanzhou university , lanzhou 730000, china Beijing Meteorological College, Beijing 100081, china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China department of atmospheric sciences Lanzhou University Lanzhou China Beijing Meteorological College Beijing China

A new concept of computational quasi-stability (CQS) is introduced to study the computational stability (CS) of the forced dissipative nonlinear (FDN) evolution equations. Based on the concept, the CQS criterion of difference scheme of FDN atmospheric equations is obtained. So it provides the theoretical basis for designing the computational stable difference scheme of FDN atmospheric equations.

关键词： computational stability (CS) computational quasi-stability (CQS) operator equation difference scheme forced dissipative nonlinear (FDN) equations.

Effects of sunspot cycle length and CO_2 on air temperature along Qinghai-Xizang railway and air temperature's trend prediction

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Science china Earth sciences 2004年第z1期47卷 131-141页

作者： LI Dongliang, QUO Hui, WANG Wen & WEI LiCold & Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, lanzhou 730000, china department of atmospheric sciences, lanzhou university, lanzhou 730000, china Cold & Arid Regions Environmental and Engineering Research Institute Chinese Academy of Science Lanzhou China department of atmospheric sciences Lanzhou University Lanzhou China

There are well coherences between annual averaged air temperatures at every meteorological station along the Qinghai-Xizang railway, and its 10-year moving average correlation coefficient is 0.92. Thus, the regional averaged annual mean temperature series along the Qinghai-Xizang railway (Trw) from 1935 to 2000 are constructed. The investigation is suggested that: Trw had significant responses to the 5-year lagged sunspot cycle length (SCL) and 15-year lagged concentration of atmospheric carbon dioxide (CO2), and the correlation coefficients between them are -0.76 (SCL) and 0.88 (CO2), respectively. The future SCL is predicted by the model of average generated function constructed with its main cycles of 76a, 93a, 108a, 205a and 275a. The result shows that the SCL would be becoming longer in the first half of the 21st century, and then it could be becoming shorter in the second half of the 21st century. Based on the natural change of SCL and the effect of double CO2 concentration, Trw in the 21st century is forecasted. It could warm up about 0.50℃ in the first half of the 21st century compared with the last decade of last century. The mean maximum air temperature could be likely about 0.20℃ in July and from 0.40℃ to 1.10℃ in January. The annual air temperature difference would likely reduce 0.3-1.00℃. The probability of above predictions ranges from 0.64 to 0.73.

关键词： Qinghai-Xizang railway, annual mean air temperature, sunspot cycle length (SCL), atmospheric carbon dioxide concentration (CO2), prediction.

Dusty cloud radiative forcing derived from satellite data for middle latitude regions of East Asia

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Progress in Natural Science:Materials International 2006年第10期16卷 1084-1089页

作者： HUANG Jianping , WANG Yujie, WANG Tianhe and YI Yuhong ( College of atmospheric sciences, lanzhou university, lanzhou 730000, china Gansu Provincial Meteorological Bureau, lanzhou 730020, china) College of atmospheric sciences Lanzhou University Lanzhou 730000 China

The dusty cloud radiative forcing over the middle latitude regions of East Asia was estimated by using the 2-year (July 2002-June 2004) data of collocated clouds and the Earth's radiant energy system (CERES) scanner and moderate resolution imaging spectroradiometer (MODIS) from Aqua Edition IB SSF (single scanner footprint). The dusty cloud is defined as the cloud in dust storm environment or dust contaminated clouds. For clouds growing in the presence of dust, the instantaneous short-wave (SW) forcing at the top of the atmosphere (TOA) is about - 275. 7 W/m for cloud over dust (COD) region. The clouds developing in no-dust cloud (CLD) regions yield the most negative short-wave (SW) forcing ( - 311.0 W/m2), which is about 12.8% stronger than those in COD regions. For long-wave (LW) radiative forcing, the no-dust cloud (CLD) is around 102.8 W/m2 , which is 20% less than the LW forcing from COD regions. The instantaneous TOA net radiative forcing for the CLD region is about - 208.2 W/m2, which is 42.1 % larger than the values of COD regions. The existence of dust aerosols under clouds significantly reduces the cooling effect of clouds.

关键词： dust storm cloud radiative forcing global warming dust aerosol-cloud-climate interaction.

Advancement and prospect of short-term numerical climate prediction

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Chinese Science Bulletin 2001年第18期46卷 1497-1502页

作者： CHOU Jifan & XU Ming1. department of atmospheric sciences, lanzhou university, lanzhou 730000, china 2. Training Center of Chinese Meteorological Administration, Beijing 100081, china department of atmospheric sciences Lanzhou University Lanzhou China Training Center of Chinese Meteorological Administration Beijing China

The defects of present methods of short-term numerical climate prediction are discussed in this paper, and four challenging problems are put forward. Considering our under developed computer conditions, we should innovate in the approcuch of numerical climate prediction on the basis of our own achievements and experiences in the field of short-term numerical climate prediction. It is possibly an effective way to settle the present defects of short-term numerical climate prediction.

关键词： short-term climate numerical prediction defects innovation.

Strengthening of the boreal winter Hadley circulation and its connection with ENSO

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Progress in Natural Science:Materials International 2007年第11期17卷 1327-1333页

作者： Ma Jie1,2 and Li Jianping2(1. College of atmospheric sciences, lanzhou university, lanzhou 730000, china 2. LASG, Institute of atmospheric Physics, Chinese Academy of sciences, Beijing 100029, china) College of atmospheric sciences Lanzhou University Lanzhou 730000 China

Empirical orthogonal function (EOF) analysis is carried out for the year-to-year variability of the boreal winter (DJF) mass stream function of the mean meridional circulation (MMC) during the period 1948—2005. The results demonstrate that it is dominated by the equatorially asymmetric and symmetric modes. Further analysis shows that the former mode is linked with the boreal winter Hadley cell mainly on the decadal time-scale, and the latter on the interannual time-scale. The asymmetric mode index (AMI) with a clear upward trend contributes to the decadal strengthening of the boreal Hadley circulation, and is closely correlated with the tropical SST warming, especially in the region of Indo-west Pacific warm pool (INWP). Furthermore, the AMI also contributes to the abrupt change of the correlation coefficient between the boreal Hadley circulation and ENSO after 1976. The symmetric mode index (SMI) with robust and stable linkage with ENSO shows a significant interannual variability, suggesting that the variability of the Hadley circulation is mainly associated with ENSO on the interannual time-scale.

关键词： the Hadley circulation interannual time-scale decadal time-scale

Comparison of sensible and latent heat fluxes during the transition season over the western Tibetan Plateau from reanalysis datasets

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Progress in Natural Science:Materials International 2009年第6期19卷 719-726页

作者： Yang Cui, Chenghai Wang Disaster Reduction Key Laboratory of Gansu Province, College of atmospheric sciences, lanzhou university, lanzhou 730000, china Disaster Reduction Key Laboratory of Gansu Province College of Atmospheric Sciences Lanzhou University Lanzhou 730000 China

The sensible and latent heat fluxes during the transition season over the western Tibetan Plateau from the NCEP-1 (NCEP/NCAR Reanalysis 1), AR-Ⅱ (NCEP-DOE Reanalysis 2) and ERA40 reanalysis datasets were compared and analyzed. The results show that the phase change in soil moisture has a significant effect on the sensible and latent heat fluxes over the western Tibetan Plateau (TP) due to the freezing-thawing processes during the transition from the dry to the wet period. The uncertainties in the sensible and latent heat fluxes over the western TP are quite high in the reanalysis data, and depend largely on the success of the soil moisture simulations in the models. Improving the hydrological process simulations in the land-surface models in seasonally frozen ground and in the active frozen soil layer may be an effective way of enhancing the reliability of the surface heat fluxes from the reanalysis data over the Tibetan Plateau.

关键词： Western Tibetan Plateau Surface heat fluxes Reanalysis data Transition season Freezing-thawing process

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 university, Kunming 650091, china Institute of atmospheric Physics Chinese Academy of Sciences Beijing China department of atmospheric Science Yunnan University Kunming 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 -0.42 and -0.49 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 effects of different sea surface temperature distributions over the western Pacific on the summer monsoon properties

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Acta Oceanologica Sinica 1993年第4期12卷 535-547页

作者： Qian Yongfu department of atmospheric sciences, Nanjing university, Nanjing 210008, china Dept. of atmospheric sciences Nanjing Univ. Nanjing 21008 China. China

A modified and improved primitive equation numerical model with p-sigma incorporated vertical coordinates is used to simulate the effects of different sea surface temperature distributions over the western Pacific on the summer monsoon properties. The different sea surface temperature (SST) distributions are automatically generated in the time integrations by using two different SST models, one of which is called the deep ocean model (DOM) and the other the shallow ocean model (SOM). The SST generated by the DOM has the distribution pattern of the initial SST which is similar to the pattern in the cold water years over the western Pacific, while the SST generated by the SOM has the pattern similar to that in the warm water years. The differences between the experimental results by using DOM and SOM are analyzed in detail. The analyses indicate that the most basic and important characteristics of the summer monsoon climate can be simulated successfully in both experiments, that means the climatic properties in the monsoonal climate regions are mainly determined by the seasonal heating, the contrast between the land and the sea, the topography, and the physical properties of the underlying surfaces. However, the differences between the two experiments tell us that the climatic properties in the summer monsoon regions in the cold water year and the warm water year do differ from each other in details. In the warm water year, the thermal contrast between the land and the sea becomes weaker. Over the warm water area, the upward motions are induced and the dynamical conditions favorable for the convective activities are formed, the Somali low-level cross equatorial current is somewhat weakened, while the cross equatorial currents, east of 90°E, are strongly strengthened, the precipitation amount in the tropical regions largely increases, and the precipitation over the coastal regions increases, too. However the precipitation over the southeast china and its coastal area d

关键词： Sea surface temperature anomaly monsoon climate modelling computational models of SST

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