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Advances in Atmospheric Sciences 2011年第3期28卷 492-510页

作者：林鹏飞刘海龙俞永强张学洪 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

The response of the upper-ocean temperatures and currents in the tropical Pacific to the spatial distribution of chlorophyll-a and its seasonal cycle is investigated using a coupled atmosphere-ocean model and a stand-alone oceanic general circulation *** spatial distribution of chlorophyll-a significantly influences the mean state of models in the tropical *** annual mean SST in the eastern equatorial Pacific decreases accompanied by a shallow thermocline and stronger currents because of shallow penetration depth of solar *** upwelling dominates the heat budget in that ***-ocean interaction processes can further amplify such changes. The seasonal cycle of chlorophyll-a can dramatically change ENSO period in the coupled *** introducing the seasonal cycle of chlorophyll-a concentration,the peak of the power spectrum becomes broad,and longer periods（3 years） are *** changes led to ENSO irregularities in the model. The increasing period is mainly due to the slow speed of Rossby waves,which are caused by the shallow mean thermocline in the northeastern Pacific.

关键词： chlorophyll-a concentration SST eastern equatorial Pacific ENSO

Paleoclimate Simulations of the Mid-Holocene and Last Glacial Maximum by FGOALS

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Advances in Atmospheric Sciences 2013年第3期30卷 684-698页

作者：郑伟鹏俞永强 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

Paleoclimate simulations of the mid-Holocene （MH） and Last Glacial maximum （LGM） by the latest versions of the Flexible Global Ocean-Atmosphere-Land System model, Spectral Version 2 and Grid-point Version 2 （FGOALS-s2 and g2） are evaluated in this study. The MH is characterized by changes of insolation induced by orbital parameters, and the LGM is a glacial period with large changes in greenhouse gases, sea level and ice sheets. For the MH, both versions of FGOALS simulate reasonable responses to the changes of insolation, such as the enhanced summer monsoon in African-Asian regions. Model differences can be identified at regional and seasonal scales. The global annual mean surface air temperature （TAS） shows no significant change in FGOALS-s2, while FGOALS-g2 shows a global cooling of about 0.7~C that is related with a strong cooling during boreal winter. The amplitude of ENSO is weaker in FGOALS-g2, which agrees with proxy data. For the LGM, FGOALS-g2 captures the features of the cold and dry glacial climate, including a global cooling of 4.6℃ and a decrease in precipitation by 10%. The ENSO is weaker at the LGM, with a tendency of stronger ENSO cold events. Sensitivity analysis shows that the Equilibrium Climate Sensitivity （ECS） estimated for FGOALS ranges between 4.23℃ and 4.59℃. The sensitivity of precipitation to the changes of TAS is -2.3%℃-1, which agrees with previous studies. FGOALS-g2 shows better simulations of the Atlantic Meridional Overturning Circulation （AMOC） and African summer monsoon precipitation in the MH when compared with FGOALS-gl.0; however, it is hard to conclude any improvements for the LGM.

关键词： paleoclimate FGOALS PMIP3 mid-Holocene LGM

A Simplified Scheme of the Generalized Layered Radiative Transfer Model

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Advances in Atmospheric Sciences 2007年第2期24卷 213-226页

作者：戴秋丹孙菽芬 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

In this paper, firstly, a simplified version （SGRTM） of the generalized layered radiative transfer model （GRTM） within the canopy, developed by us, is presented. It reduces the information requirement of inputted sky diffuse radiation, as well as of canopy morphology, and in turn saves computer resources. Results from the SGRTM agree perfectly with those of the GRTM. Secondly, by applying the linear superposition principle of the optics and by using the basic solutions of the GRTM for radiative transfer within the canopy under the condition of assumed zero soil reflectance, two sets of explicit analytical solutions of radiative transfer within the canopy with any soil reflectance magnitude are derived： one for incident diffuse, and the other for direct beam radiation. The explicit analytical solutions need two sets of basic solutions of canopy reflectance and transmittance under zero soil reflectance, run by the model for both diffuse and direct beam radiation. One set of basic solutions is the canopy reflectance αf （written as α1 for direct beam radiation） and transmittance βf （written as β1 for direction beam radiation） with zero soil reflectance for the downward radiation from above the canopy （i.e. sky）, and the other set is the canopy reflectance （αb） and transmittance βb for the upward radiation from below the canopy （i.e., ground）. Under the condition of the same plant architecture in the vertical layers, and the same leaf adaxial and abaxial optical properties in the canopies for the uniform diffuse radiation, the explicit solutions need only one set of basic solutions, because under this condition the two basic solutions are equal, i.e., αf = αb and βf = βb. Using the explicit analytical solutions, the fractions of any kind of incident solar radiation reflected from （defined as surface albedo, or canopy reflectance）, transmitted through （defined as canopy transmittance）, and absorbed by （defined as canopy absorptance） the canopy and other properties pertine

关键词： generalized layered canopy radiative transfer model simplified model analytical solutions basic solutions adaxial abaxial leaf optical properties

An Assessment of Improvements in Global Monsoon Precipitation Simulation in FGOALS-s2

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Advances in Atmospheric Sciences 2014年第1期31卷 165-178页

作者： ZHANG Lixia ZHOU Tianjun State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

The performance of Version 2 of the Flexible Global Ocean-Atmosphere-Land System model （FGOALS-s2） in simulat ing global monsoon precipitation （GMP） was evaluated. Compared with FGOALS-sl, higher skill in simulating the annual modes of climatological tropical precipitation and interannual variations of GMP are seen in FGOALS-s2. The simulated domains of the northwestern Pacific monsoon （NWPM） and North American monsoon are smaller than in FGOALS-s 1. The main deficiency of FGOALS-s2 is that the NWPM has a weaker monsoon mode and stronger negatiw,＇ pattern in spring-fall asymmetric mode. The smaller NWPM domain in FGOALS-s2 is due to its simulated colder SST over the western Pacific warm pool. The relationship between ENSO and GMP is simulated reasonably by FGOALS-s2. However, the simulated precipitation anomaly over the South African monsoon region-South Indian Ocean during La Nina years is opposite to the observation. This results mainly from weaker warm SST anomaly over the maritime continent during La Nifia years, leading to stronger upper-troposphere （lower-troposphere） divergence （convergence） over the Indian Ocean, and artificial vertical as cent （descent） over the Southwest Indian Ocean （South African monsoon region）, inducing local excessive （deficient） rainfall. Comparison between the historical and pre-industrial simulations indicated that global land monsoon precipitation changes from 1901 to the 1970s were caused by internal variation of climate system. External forcing may have contributed to the increasing trend of the Australian monsoon since the 1980s. Finally, it shows that global warming could enhance GMR especially over the northern hemispheric ocean monsoon and southern hemispheric land monsoon.

关键词： global monsoon precipitation climate model annual mode climate change

Impacts of Two Types of Northward Jumps of the East Asian Upper-tropospheric Jet Stream in Midsummer on Rainfall in Eastern China

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Advances in Atmospheric Sciences 2013年第4期30卷 1224-1234页

作者：林中达 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

The East Asian upper-tropospheric jet stream （EAJS） typically jumps north of 45~N in midsummer. These annual northward jumps are mostly classified into two dominant types： the first type corresponds to the enhanced westerly to the north of the EAJS＇s axis （type A）, while the second type is related to the weakened westerly within the EAJS＇s axis （type B）. In this study, the impacts of these two types of northward jumps on rainfall in eastern China are investigated. Our results show that rainfall significantly increases in northern Northeast China and decreases in the Yellow River-Huaihe River valleys, as well as in North China, during the type A jump. As a result of the type B jump, rainfall is enhanced in North China and suppressed in the Yangtze River valley. The changes in rainfall in eastern China during these two types of northward jumps are mainly caused by the northward shifts of the ascending air flow that is directly related to the EAJS. Concurrent with the type A （B） jump, the EAJS-related ascending branch moves from the Yangtze-Huai River valley to northern Northeast （North） China when the EAJS＇s axis jumps from 40~N to 55~N （50~N）. Meanwhile, the type A jump also strengthens the Northeast Asian low in the lower troposphere, leading to more moisture transport to northern Northeast China. The type B jump, however, induces a northwestward extension of the lower-tropospheric western North Pacific subtropical high and more moisture transport to North China.

关键词： northward jump East Asian upper-tropospheric jet stream eastern China rainfall Northeast Asian low western North Pacific subtropical high

Changes in Winter Stratospheric Circulation in CMIP5 Scenarios Simulated by the Climate System Model FGOALS-s2

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Advances in Atmospheric Sciences 2012年第6期29卷 1374-1389页

作者：任荣彩杨扬 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

Diagnosis of changes in the winter stratospheric circulation in the Fifth Coupled Model Intercomparison Project （CMIP5） scenarios simulated by the Flexible Global Ocean-Atmosphere-Land System model, second version spectrum （FGOALS-s2）, indicates that the model can generally reproduce the present climatology of the stratosphere and can capture the general features of its long-term changes during 1950-2000, including the global stratospheric cooling and the strengthening of the westerly polar jet, though the simulated polar vortex is much cooler, the jet is much stronger, and the projected changes are generally weaker than those revealed by observation data. With the increase in greenhouse gases （GHGs） effect in the historical simu- lation from 1850 to 2005 （called the HISTORICAL run） and the two future projections for Representative Concentration Pathways （called the RCP4.5 and RCP8.5 scenarios） from 2006 to 2100, the stratospheric response was generally steady, with an increasing stratospheric cooling and a strengthening polar jet ex- tending equatorward. Correspondingly, the leading oscillation mode, defined as the Polar Vortex Oscillation （PVO）, exhibited a clear positive trend in each scenario, confirming the steady strengthening of the polar vortex. However, the positive trend of the PVO and the strengthening of the polar jet were not accompa- nied by decreased planetary-wave dynamical heating, suggesting that the cause of the positive PVO trend and the polar stratospheric cooling trend is probably the radiation cooling effect due to increase in GHGs. Nevertheless, without the long-term linear trend, the temporal variations of the wave dynamic heating, the PVO, and the polar stratospheric temperature are still closely coupled in the interannual and decadal time scales.

关键词： simulated changes stratosphere CMIP5 FGOALS-s2

Dominant Patterns of Summer Rainfall Anomalies in East China during 1951-2006

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Advances in Atmospheric Sciences 2012年第4期29卷 695-704页

作者：叶红陆日宇 State Key laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

The dominant patterns of summer rainfall anomalies in East China were studied using Empirical Orthogonal Function （EOF） analysis. The results indicate that after the late 1970s, the first and second dominant patterns switched. During the period before the late 1970s, the spatial pattern of the first （second） dominant mode was the ＂Yangtze River pattern＂（the ＂South China pattern＂）, but this changed to the ＂South China pattern＂（the ＂Yangtze River pattern＂） after the late 1970s. This decadal change in the dominant patterns resulted from a significant decadal change in summer rainfall over South China after the late 1970s, i.e., a negative phase during 1978-1992 and a positive phase during 1993-2006. When the decadal variation of rainfall in East China is omitted from the analysis, the first and second dominant patterns represent the ＂Yangtze River pattern＂ and the ＂South China pattern＂, respectively. These results suggest that when decadal variation is included, the rainfall in China may be dominated by one mode during certain periods and by another in other periods. For the interannual variability when decadal variation is excluded, however, the first and second modes can be easily distinguished, and their order has been stable since at least 1951.

关键词： dominant patterns summer rainfall interannual variability South China decadal variation

The Significant Relationship between the Arctic Oscillation (AO) in December and the January Climate over South China

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Advances in Atmospheric Sciences 2011年第2期28卷 398-407页

作者：杨辉 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

Using NCEP/NCAR reanalysis data, the China rainfall and surface temperature data of the China Meteorological Administration, and the Arctic Oscillation （AO） indices of NOAA, the author investigates relationships between the AO and the precipitation and temperature over China. There exists a good relationship between the AO index in December and the succeeding January precipitation over South China, indicating that when the December AO index is positive （negative）, the January precipitation over South China increases （decreases）. A remarkable negative correlation between the December AO index and the January surface temperature also exists over South China, indicating that when the December AO index is positive （negative）, the January temperature over South China drops （rises）. The occurrence of this anomalous climate is related to the anomalies of the atmospheric circulation systems. The December AO greatly influences circulation anomalies in January. A positive phase of the AO is found to lead to a stronger subtropical jet over the south side from the Iran Plateau to the Tibetan Plateau. Consequently, it results in a deepening pressure trough around the Bay of Bengal, which transports the warm and wet air to South China continuously. The Siberian High in January is stronger and extends farther southeastward. It results in continual cold air at 1000 hPa pouring into South China, inducing low temperature. Cooperating with the trough of the Bay of Bengal, anomalous precipitation occurs over South China. For the negative phase of the December AO, the opposite situation is observed.

关键词： Arctic Oscillation precipitation surface temperature large-scale circulation

Oceanic Climatology in the Coupled Model FGOALS-g2: Improvements and Biases

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Advances in Atmospheric Sciences 2013年第3期30卷 819-840页

作者：林鹏飞俞永强刘海龙 State Key laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical fluid dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

The present study examines simulated oceanic climatology in the Flexible Global Ocean-Atmosphere- Land System model, Grid-point Version 2 （FGOALS-g2） forced by historical external forcing data. The oceanic temperatures and circulations in FGOALS-g2 were found to be comparable to those observed, and substantially improved compared to those simulated by the previous version, FGOALS-gl.0. Compared with simulations by FGOALS-gl.0, the shallow mixed layer depths were better captured in the eastern Atlantic and Pacific Ocean in FGOALS-g2. In the high latitudes of the Northern Hemisphere, the cold biases of SST were about 1℃-5℃ smaller in FGOALS-g2. The associated sea ice distributions and their seasonal cycles were more realistic in FGOALS-g2. The pattern of Atlantic Meridional Overturning Circulation （AMOC） was better simulated in FGOALS-g2, although its magnitude was larger than that found in observed data. The simulated Antarctic Circumpolar Current （ACC） transport was about 140 Sv through the Drake Passage, which is close to that observed. Moreover, Antarctic Intermediate Water （AAIW） was better captured in FGOALS-g2. However, large SST cold biases （〉3℃） were still found to exist around major western boundary currents and in the Barents Sea, which can be explained by excessively strong oceanic cold advection and unresolved processes owing to the coarse resolution. In the Indo-Pacific warm pool, the cold biases were partly related to the excessive loss of heat from the ocean. Along the eastern coast in the Atlantic and Pacific Oceans, the warm biases were due to overestimation of shortwave radiation. In the Indian Ocean and Southern Ocean, the surface fresh biases were mainly due to the biases of precipitation. In the tropical Pacific Ocean, the surface fresh biases （〉2 psu） were mainly caused by excessive precipitation and oceanic advection. In the Indo-Pacific Ocean, fresh biases were also found to dominate in the upper 1000 m, except in the northeastern Indian Ocea

关键词： FGOALS-g2 oceanic climatology temperature salinity ocean circulation

Numerical study on the gas-kinetic high-order schemes for solving Boltzmann model equation

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Science China(Physics,Mechanics & Astronomy) 2011年第9期54卷 1687-1701页

作者： LI ZhiHui PENG AoPing ZHANG HanXin DENG XiaoGang National laboratory for Computational fluid dynamics Beifing 100191 China China Aerodynamics Research and Development Center Mianyang 621000 China

The high-order compact finite difference technique is introduced to solve the Boltzmann model equation, and the gas-kinetic high-order schemes are developed to simulate the different kinetic model equations such as the BGK model, the Shakhov model and the Ellipsoidal Statistical (ES) model in this paper. The methods are tested for the one-dimensional unsteady shock-tube problems with various Knudsen numbers, the inner flows of normal shock wave for different Mach numbers, and the two-dimensional flows past a circular cylinder and a NACA 002 airfoil to verify the reliability of the present high-order algorithm and simulate gas transport phenomena covering various flow regimes. The computed results are found in good agreement both with the theoretical prediction from continuum to rarefied gas dynamics, the related DSMC solutions, and with the experimental results. The numerical effect of the schemes with the different precision and the different types of Boltzmann collision models on the computational efficiency and computed results is investigated and analyzed. The numerical experience indicates that an approach developing and applying the gas-kinetic high-order algorithm is feasible for directly solving the Boltzmann model equation.

关键词： Boltzmann model equation velocity distribution function high-order compact scheme discrete velocity ordinate method gas-kinetic high order accurate algorithm