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1.
Summary Due to the strong variation of the Asian monsoon, many countries in Asia often suffer from serious natural disasters. Droughts and floods appear in East China frequently related to the large anomalies of the two branches of East Asian monsoon. Based on rainfall data recorded by 336 Chinese stations in the 1980s, two distinctly opposite rainfall types over East China in summer (JJA) are discovered. Correspondly, 850 hPa anomalous wind fields in the Eastern Hemisphere are also possessed by two types of converse patterns in spring (MAM) and summer (JJA). The onset time and intensity of the Somali jet and the two branches of Southeast and Indian monsoon are quite different. Furthermore, in the 500 hPa geopotential height anomaly fields in spring and summer, the variations of the previous general atmospheric circulation (in spring) are closely correlated to the two kinds of conversely distributed rainfall in summer. These two types of rainfall are also related to two types of conversely distributed sea surface temperature anomaly (SSTA) in the equatorial Pacific and Indian Oceans. To investigate model capabilities refelecting the above observed features, eight numerical experiments are carried out using the IAP 2-L AGCM, with observed monthly mean global SSTs as external forcing and observed atmospheric data on February 15 as initial conditions. The simulated distributions of rainfall anomalies over East China in summer are in good accordance with observations. With conversely distributed SSTAs in the equatorial Pacific, the simulated 850 hPa anomalous wind fields and the 500 hPa geopotential height anomalies are also conversely distributed, and are closely related to the two types of simulated rainfall anomalies over East China. The cross equatorial wind varies in strength, space and time. The simulated distributions of anomalous 500 hPa geopotential height in spring and the anomalous wind at 850 hPa in spring and summer are quite similar to observations.With 10 Figures 相似文献
2.
East Asian summer monsoon simulation by a 20-km mesh AGCM 总被引：1，自引：0，他引：1
East Asian summer monsoon climate simulated by a global 20-km mesh atmospheric general circulation model (AGCM) forced by
the global sea surface temperature during the period 1979–1998 is investigated. In comparison with a lower resolution (180-km
mesh) model experiment, it is revealed that the 20-km mesh AGCM shows the superiority in simulating orographic rainfall not
only its location but also its amount. The Baiu frontal structure is also better simulated in the higher resolution model,
which leads to stronger Baiu rainfall. The 20-km model also shows more intense extremes in precipitation. Interannual variability
of June–August mean precipitation and seasonal march of the monsoon rain band are also investigated.
This paper is a contribution to the AMIP-CMIP Diagnostic Sub-project on General Circulation Model Simulation of the East Asian
Climate, coordinated by W.-C. Wang. 相似文献
3.
In this paper, a 5-level spectral AGCM is used to examine the sensitivity of simulated East Asian summer monsoon circulation
and rainfall to cumulus parameterization schemes. From the simulated results of East Asian monsoon circulations and rainfalls
during the summers of 1987 and 1995, it is shown that the Kuo’s convective parameterization scheme is more suitable for the
numerical simulation of East Asian summer monsoon rainfall and circulation. This may be due to that the cumulus in the rainfall
system is not strong in the East Asian monsoon region.
This paper is supported by the National Key Progranmme “96-908”. 相似文献
4.
Simulation of East Asian Summer Monsoon with IAP CGCM 总被引：1，自引：0，他引：1
ＳｉｍｕｌａｔｉｏｎｏｆＥａｓｔＡｓｉａｎＳｕｍｍｅｒＭｏｎｓｏｏｎｗｉｔｈＩＡＰＣＧＣＭＣｈｅｎＱｉｙｉｎｇ（陈起英），①ＹｕＹｏｎｇｑｉａｎｇ（俞永强）ａｎｄＧｕｏＹｕｆｕ（郭裕福）ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙｓｉｃｓ，Ｃｈ... 相似文献
5.
ＴｈｅＥｆｅｃｔｏｆＨｅａｔｉｎｇＡｎｏｍａｌｙｏｎｔｈｅＡｓｉａｎＣｉｒｃｕｌａｔｉｏｎ－ＡＧＣＭＥｘｐｅｒｉｍｅｎｔ①ＷａｎｇＨｕｉｊｕｎ（王会军）ＬＡＳＧ，ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙｓｉｃｓ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙ... 相似文献
6.
Wang Huijun 《大气科学进展》1997,14(1):81-86
A numerical experiment was done by using the IAP 9-Level AGCM to study the effects of radiation anomaly over East Asia on the Asian general circulation. The results show that the changes of Asian summer general circula-tion are remarkable in the Indian and China southwest monsoon, precipitation in India and the Yellow River and Huaihe River valley in China and area around the north Japan, the easterly anomaly of low-level zonal wind in the tropical Pacific and so on. 相似文献
7.
东亚夏季风降水和环流数值模拟对不同对流参数化方案的敏感性 总被引：4，自引：2，他引：4
A 5-level spectral AGCM (ImPKU-5LAGCM) is used to examine the sensitivity of the simulated results of the summer monsoon rainfall and circulation in East Asia to different cumulus parameterization schemes in the climatological-mean case and in the cases of weak and strong Asian summer monsoons,respectively. The results simulated with the Arakawa-Schubert＇s(hereafter A-S＇s), Kuo＇s and Manabe＇s cumulus parameterization schemes show that these simulated distributions of the summer monsoon rainfall and circulation in East Asia depend strongly on the cumulus parameterization schemes either in the climatological-mean case or in the cases of weak and strong Asian summer monsoons. From the simulated results, it might be shown that the Kuo scheme appears to be more suitable for the simulation of the summer monsoon rainfall and circulation in East Asia than the A-S scheme or the Manabe scheme, although the A-S scheme is somewhat better in the simulations of the tropical rainfall. This might be due to that the Kuo＇s cumulus parameterization scheme is able to reflect well the characteristics of rainfall cloud system in the East Asian summer monsoon region, where the rainfall system used to be a mixing of cumulus and stratus. 相似文献
8.
LIN Zhaohui WANG Huijun ZHOU Guangqing CHEN Hong LANG Xianmei ZHAO Yan ZENG Qingcun 《大气科学进展》2004,21(3):456-466
Recent advances in dynamical climate prediction at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP/CAS) during the last five years have been briefly described in this paper. Firstly,the second generation of the IAP dynamical climate prediction system (IAP DCP-II) has been described,and two sets of hindcast experiments of the summer rainfall anomalies over China for the periods of 1980-1994 with different versions of the IAP AGCM have been conducted. The comparison results show that the predictive skill of summer rainfall anomalies over China is improved with the improved IAP AGCM in which the surface albedo parameterization is modified. Furthermore, IAP DCP-II has been applied to the real-time prediction of summer rainfall anomalies over China since 1998, and the verification results show that IAP DCP-II can quite well capture the large scale patterns of the summer flood/drought situations over China during the last five years (1998-2002). Meanwhile, an investigation has demonstrated the importance of the atmospheric initial conditions on the seasonal climate prediction, along with studies on the influences from surface boundary conditions (e.g., land surface characteristics, sea surface temperature).Certain conclusions have been reached, such as, the initial atmospheric anomalies in spring may play an important role in the summer climate anomalies, and soil moisture anomalies in spring can also have a significant impact on the summer climate anomalies over East Asia. Finally, several practical techniques(e.g., ensemble technique, correction method, etc.), which lead to the increase of the prediction skill for summer rainfall anomalies over China, have also been illustrated. The paper concludes with a list of criticalre quirements needed for the further improvement of dynamical seasonal climate prediction. 相似文献
9.
Bhaskar Preethi Milind Mujumdar Amita Prabhu Ramesh Kripalani 《Asia-Pacific Journal of Atmospheric Sciences》2017,53(2):305-325
Coupled Model Inter-comparison Project Phase 5 (CMIP5) model outputs of the South and East Asian summer monsoon variability and their tele-connections are investigated using historical simulations (1861-2005) and future projections under the RCP4.5 scenario (2006-2100). Detailed analyses are performed using nine models having better representation of the recent monsoon teleconnections for the interactive Asian monsoon sub-systems. However, these models underestimate rainfall mainly over South Asia and Korea-Japan sector, the regions of heavy rainfall, along with a bias in location of rainfall maxima. Indeed, the simulation biases, underestimations of monsoon variability and teleconnections suggest further improvements for better representation of Asian monsoon in the climate models. Interestingly, the performance of Australian Community Climate and Earth System Simulator version 1.0 (ACCESS1.0) in simulating the annual cycle, spatial pattern of rainfall and multi-decadal variations of summer monsoon rainfall over South and East Asia appears to more realistic. In spite of large spread among the CMIP5 models, historical simulations as well as future projections of summer monsoon rainfall indicate multi-decadal variability. These rainfall variations, displaying certain epochs of more rainfall over South Asia than over East Asia and vice versa, suggest an oscillatory behaviour. Teleconnections between South and East Asian monsoon rainfall also exhibit a multi-decadal variation with alternate epochs of strengthening and weakening relationship. Furthermore, large-scale circulation features such as South Asian monsoon trough and north Pacific subtropical high depict zonal oscillatory behaviour with east-west-east shifts. Periods with eastward or westward extension of the Mascarene High, intensification and expansion of the upper tropospheric South Asian High are also projected by the CMIP5 models. 相似文献
10.
Simulation of the asian monsoon by IAP AGCM coupled with an advanced land surface model (IAP94) 总被引：3，自引：0，他引：3
ＳｉｍｕｌａｔｉｏｎｏｆｔｈｅＡｓｉａｎＭｏｎｓｏｏｎｂｙＩＡＰＡＧＣＭＣｏｕｐｌｅｄｗｉｔｈａｎＡｄｖａｎｃｅｄＬａｎｄＳｕｒｆａｃｅＭｏｄｅｌ（ＩＡＰ９４）ＺｅｎｇＱｉｎｇｃｕｎ（曾庆存）,ＤａｉＹｏｎｇｊｉｕ（戴永久）ａｎｄＸｕｅＦｅｎｇ（薛峰... 相似文献
11.
The role of various mountains in the Asian monsoon system is investigated by
AGCM simulations with different mountains. The comparison of the simulation
with Asian mountains (MAsia run) with the simulation without mountains (NM
run) reveals that the presence of the Asian mountains results in a stronger
South Asian summer monsoon (SASM), characterized by enhanced
lower-tropospheric westerly winds, upper-tropospheric easterly winds, and
stronger water vapor convergence. In East Asia, the southerly winds and
water vapor convergence are significantly strengthened in association with
the intensified zonal pressure gradient between the East Asian continent and
the Pacific Ocean. Both the dynamical and thermodynamic forcing of the
Tibetan Plateau play important role in strengthening the Asian summer
monsoon. In winter, the presence of Asian mountains significantly
strengthens the continental high, which leads to a stronger Asian winter
monsoon. The presence of African--Arabian mountains helps to intensify the
exchange of mass between the Southern Hemisphere and Northern Hemisphere by
strengthening the cross equatorial flows in the lower and upper troposphere
over East Africa.
Asian mountains also play a crucial role in the seasonal evolution of Asian
monsoons. In comparison with the NM run, the earlier onset and later
withdrawal of lower-tropospheric westerly winds can be found over South Asia
in the MAsia run, indicating a longer SASM period. The African--Arabian
mountains also moderately contribute to the seasonal variation of the South
Asian monsoon. In East Asia, the clear south-to-north march of the southerly
winds and subtropical rainfall starts to occur in early summer when the
effects of Asian mountains are considered. 相似文献
12.
Simulation of paleoclimate over East Asia at 6 ka BP and 21 ka BP by a regional climate model 总被引：5，自引：0，他引：5
Using a regional climate model with detailed land surface processes (RegCM2), East Asian monsoon climates at 6 ka BP and 21 ka BP are simulated by prescribing vegetation and employing paleovegetation respectively in order to examine land surface effects on East Asian climate system and the potential mechanisms for climate change. The RegCM2 with a 120 × 120 km2 resolution has simulated the enlargement of the seasonal cycle of insolation, the temperature rising the whole year, and the reduction of perpetual snow in high latitudes at 6 ka BP. The simulation shows the East Asian summer monsoon strengthening, precipitation and P–E increasing, and the monsoon rain belt shifting westwards and northwards. Effect of paleovegetation included in the modeling reduced surface albedo and caused an increase in the winter temperature, which led to weakening of the winter continental cold anticyclone over China. The results make the seasonal characteristics of simulated temperature changes in better agreement with the geological records, and are an improvement over previous simulations of Paleoclimate Modeling Intercomparison Project (PMIP). The RegCM2 simulated the 21 ka BP climate with lowered temperature throughout the year, and with precipitation reduced in most areas of East Asia (but increased in both the Tibetan Plateau and Central Asia). Low temperature over East Asia led to the strengthening of the East Asian winter monsoon and the shrinking of the summer monsoon. The effect of paleovegetation included in the experiment has enlarged the glacial climate influence in East Asia, which is closer to geological data than the PMIP simulations directly driven by insolation, glaciation and low CO2 concentration. 相似文献
13.
The seasonal variations of the Asian monsoon were explored by applying the atmospheric general circulation model R42L9 that was developed recently at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP/CAS). The 20-yr (1979-1998) simulation was done using the prescribed 20-yr monthly SST and sea-ice data as required by Atmospheric Model Intercomparison Project (AMIP)Ⅱ in the model. The monthly precipitation and monsoon circulations were analyzed and compared with the observations to validate the model‘s performance in simulating the climatological mean and seasonal variations of the Asian monsoon. The results show that the model can capture the main features of the spatial distribution and the temporal evolution of precipitation in the Indian and East Asian monsoon areas. The model also reproduced the basic patterns of monsoon circulation. However, some biases exis tin this model. The simulation of the heating over the Tibetan Plateau in summer was too strong. The overestimated heating caused a stronger East Asian monsoon and a weaker Indian monsoon than the observations. In the circulation fields, the South Asia high was stronger and located over the Tibetan Plateau. The western Pacific subtropical high was extended westward, which is in accordance with the observational results when the heating over the Tibetan Plateau is stronger. Consequently, the simulated rainfall around this area and in northwest China was heavier than in observations, but in the Indian monsoon area and west Pacific the rainfall was somewhat deficient. 相似文献
14.
Influence of the Mascarene High and Australian High on the Summer Monsoon in East Asia： Ensemble Simulation 总被引：11，自引：0，他引：11
By using a nine-level atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP 9L AGCM), two sets of numerical experiments are carried out to investigate the influence of the Mascarene high (MH) and Australian high (AH) over the southern subtropics upon the East Asian summer monsoon circulation and summer precipitation in East Asia. The use of ensemble statistics is adopted to reduce the simulation errors. The result shows that with the intensification of MH, the Somali low-level jet is significantly enhanced together with the summer monsoon circulation in the tropical Asia and western Pacific region. Furthermore, the anticyclonic anomaly in the tropical western Pacific to the east of the Philippines may induce a weak East-Asia-Pacific teleconnection pattern. In the meantime,geopotential height in the Tropics is enhanced while it is reduced over most regions of mid-high latitudes,thus the northwestern Pacific subtropical high at 500 hPa extends southwestward, resulting in more rainfall in southern China and less rainfall in northern China. A similar anomaly pattern of the atmospheric circulation systems is found in the experiment of the intensification of AH. On the other hand, because the cross-equatorial currents associated with AH are much weaker than the Somali jet, the anomaly magnitude caused by the intensification of AH is generally weak, and the influence of AH on summer rainfall in China seems to be localized in southern China. Comparison between the two sets of experiments indicates that MH plays a crucial role in the interactions of general atmospheric circulation between the two hemispheres. 相似文献
15.
16.
Ｉ．ＩＮＴＲＯＤＵＣＴＩＯＮＥａｓｔＡｓｉａｉｓｓｉｔｕａｔｅｄｉｎｔｈｅｅａｓｔｅｒｎｐａｒｔｏｆｔｈｅＥｕｒａｓｉａｎｃｏｎｔｉｎｅｎｔｗｈｅｒｅｔｈｅｈｕｇｅＴｉｂｅｔａｎＰｌａｔｅａｕｅｘｉｓｔｓ．Ｆａｃｉｎｇｅａｓｔａｎｄｓｏｕｔｈｅａｓｔ... 相似文献
17.
This study evaluates the simulation of the coherent circulation structure correspond to the changes of mid-summer (July–August) rainfall over eastern China (30°–40° N, 110°–120° E) in high-resolution NCAR CAM5. Forced by historical sea surface temperatures (SSTs), the NCAR CAM5 reasonably reproduces coherent changes of temperature and large-scale circulations, corresponding to the changes in rainfall. Results show that when the rainfall decreases over eastern China, the model reproduces a remarkable warm center in the upper troposphere with an anomalous anticyclone appears above and an increase in anomalous westerlies to its north. An anomalous anticyclone also occurs in the lower troposphere, along with anomalous southerlies to its east which indicates strengthening of the East Asian summer monsoon. Both the circulation changes in the upper and lower troposphere favor a decrease in precipitation over central eastern China. There were also good correlations between the simulated upper-tropospheric temperature and other large-scale circulation changes. There are some deficiencies in the NCAR CAM5 simulations in terms of the changes in magnitude and location of the rainfall centers. However, in general, the model reasonably reproduced the coherent configuration of the large-scale circulation patterns and surface rainfall. This study further confirms that the climate variations across East Asia most likely arise from a regional response to global climate change. The well-simulated configuration by NCAR CAM5 also indicates the reliability of the model and its potential to reveal the mechanisms driving the coherent changes of the East Asian summer monsoon system. 相似文献
18.
A Possible Impact of Cooling over the Tibetan Plateau on the Mid-Holocene East Asian Monsoon Climate 总被引：5，自引：3，他引：5
By using a 9-level global atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP9L-AGCM) under the Chinese Academy of Sciences, the authors investigated the response of the East Asian monsoon climate to changes both in orbital forcing and the snow and glaciers over the Tibetan Plateau at the mid-Holocene, about 6000 calendar years before the present (6 kyr BP). With the Earth’s orbital parameters appropriate for the mid-Holocene, the IAP9L-AGCM computed warmer and wetter conditions in boreal summer than for the present day. Under the precondition of continental snow and glacier cover existing over part of the Tibetan Plateau at the mid-Holocene, the authors examined the regional climate response to the Tibetan Plateau cooling. The simulations indicated that climate changes in South Asia and parts of central Asia as well as in East Asia are sensitive to the Tibetan Plateau cooling at the mid-Holocene, showing a significant decrease in precipitation in northern India, northern China and southern Mongolia and an increase in Southeast Asia during boreal summer. The latter seems to correspond to the weakening, southeastward shift of the Asian summer monsoon system resulting from reduced heat contrast between the Eurasian continent and the Pacific and Indian Oceans when a cooling over the Tibetan Plateau was imposed. The simulation results suggest that the snow and glacier environment over the Tibetan Plateau is an important factor for mid-Holocene climate change in the areas highly influenced by the Asian monsoon. 相似文献
19.
A possible role of solar radiation and ocean in the mid-Holocene East Asian monsoon climate 总被引：8，自引：5，他引：3
An atmospheric general circulation model (AGCM) and an oceanic general circulation model (OGCM) are asynchronously coupled to simulate the climate of the mid-Holocene period. The role of the solar radiation and ocean in the mid-Holocene East Asian monsoon climate is analyzed and some mechanisms are revealed. At the forcing of changed solar radiation induced by the changed orbital parameters and the changed SST simulated by the OGCM, compared with when there is orbital forcing alone, there is more precipitation and the monsoon is stronger in the summer of East Asia, and the winter temperature increases over China. These agree better with the reconstructed data. It is revealed that the change of solar radiation can displace northward the ITCZ and the East Asia subtropical jet, which bring more precipitation over the south of Tibet and North and Northeast China. By analyzing the summer meridional latent heat transport, it is found that the influence of solar radiation change is mainly to increase the convergence of atmosphere toward the land, and the influence of SST change is mainly to transport more moisture to the sea surface atmosphere. Their synergistic effect on East Asian precipitation is much stronger than the sum of their respective effects. 相似文献
20.
青藏高原增暖对东亚夏季风的影响——大气环流模式数值模拟研究 总被引：7，自引：4，他引：3
20世纪50年代以来,随着全球海表面温度年代际变化和全球变暖现象的出现,东亚夏季风降水和环流场也出现相应的年代际变化。是什么原因引起这个长期的变化趋势？研究表明青藏高原增暖可能是导致东亚夏季风年代际变化的重要因子之一。为了能够更好地理解青藏高原地表状况对下游东亚季风的影响,作者使用德国马普气象研究所大气环流模式（ECHAM）进行一系列数值试验。在两组敏感性试验中,通过改变高原上的地表反照率从而达到改变地表温度的目的。数值试验结果表明:青藏高原增暖有助于增强对流层上层的南亚高压、高原北侧西风急流和高原南侧东风急流以及印度低空西南季风;与此同时,东亚地区低层西南气流水汽输送增强。高原增暖后降水场的变化表现为:印度西北部季风降水增加,长江中下游以及朝鲜半岛梅雨降水增多;在太平洋副热带高压控制下的西北太平洋地区和孟加拉湾东北部,季风降水减少。对数值模拟结果的初步诊断分析表明:在感热加热和对流引起的潜热加热相互作用下,南亚高压强度加强,东亚夏季低层西南季风增大、梅雨锋降水增强,高原东部对流层上层的副热带气旋性环流增加,以及对流层低层的西太平洋副热带高压增强。另外,在青藏高原增暖的背景下,孟加拉湾地区季风降水减弱。本项研究有助于更好地理解东亚夏季风年代际变化特征和未来气候变化趋势。 相似文献