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| 热带大气季节内振荡的季节性特征及其在SAMIL-R42L9中的表现 |
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贾小龙1,2, 李崇银2,3
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1.国家气候中心, 北京, 100081;2.中科院大气所大气科学和地球流体力学数值模拟国家重点实验室, 北京, 100029;3.解放军理工大学气象学院, 江苏, 南京, 211101
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| 摘要: |
| 分析了NCEP资料和SAMIL-R42L9中热带大气季节内(30～60天)振荡(ISO)的季节变化特征及其与平均气候场季节变化的关系。NCEP资料的分析表明:热带地区大气ISO在空间分布上存在明显的季节变化,大气ISO的季节变化与平均背景场的季节变化有明显的一致性。在空间分布上,热带大气ISO的活动对暖的SST、强的对流活动、西风、强的降水和低层水汽辐合有很强的依赖性。大气环流模式SAMIL-R42L9基本能够再现热带大气ISO空间分布上的季节转换特征,尤其在动力场(纬向风)上表现得最为明显。但对基本气候态季节变化的模拟,对不同的物理量有明显的差异。模式结果表明:热带大气ISO动力因子的季节性比热力因子的季节性对平均背景场的依赖性更大,模式不能很好地反映NCEP资料表现出来的ISO对平均背景场的强依赖性,同时也说明热带大气ISO的季节性可能并不完全依赖于平均背景场的季节变化。 |
| 关键词: 热带大气季节内振荡(ISO) 季节变化 气候背景 大气环流模式 |
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| 基金项目:国家自然科学基金(40575027;40675051);中科院创新项目(KZCX3-sw-226)共同资助 |
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| SEASONAL VARIATIONS OF THE TROPICAL INTRASEASONAL OSCILLATION AND ITS REPRODUCTION IN SAMIL-R42L9 |
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JIA Xiao-long1,2, LI Chong-yin2,3
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1.National Climate Center, Beijing 100081, China;2.State Key Laboratory of Numerical Modeling for Atmospheric Science and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 100029, China;3.Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101, China
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| Abstract: |
| Seasonal variations of the tropical intraseasonal oscillation(ISO) and relationship to seasonal variation of the climate background are studied by using NCEP/NCAR reanalysis data and output of SAMIL-R42L9. Analysis of NCEP data shows that spatial distribution of the tropical ISO has obvious seasonal variations,which are well consistent with the seasonal variation of climate background. The activity of the tropical ISO is,to a great extent,dependent on warm SST,strong convection,zonal western wind,strong precipitation and low-level moisture convergence. Main characteristics of the seasonal variations of the tropical ISO are captured by SAMIL-R42L9. Simulations of seasonal variation of climate background vary greatly with different variables. Results of SAMIL-R42L9 indicate that the seasonal variations of the tropical ISO in dynamical fields are more depended on climate background than in heating fields and SAMIL-R42L9 cannot represent well the strong dependence of the ISO on the climate background present in NCEP/NCAR reanalysis data. It also suggests that seasonal variations of the ISO do not completely depend on that of climate background. |
| Key words: tropical intraseasonal oscillation seasonal variation climate background GCM |