林爱兰,Tim Li,李春晖,谷德军,郑彬,Jing Jia Luo. 2010. 印度洋海温年际异常与热带夏季季节内振荡的关系及其数值模拟研究[J]. 气象学报, 68(5):617-630, doi:10.11676/qxxb2010.061
印度洋海温年际异常与热带夏季季节内振荡的关系及其数值模拟研究
Relationships between interannual anomalies of sea surface temperature in the Indian Ocean and tropical boreal summer intraseasonal oscillations: Observations and simulations
投稿时间:2009-07-20  修订日期:2009-08-13
DOI:10.11676/qxxb2010.061
中文关键词:  印度洋海温, 热带夏季季节内振荡, 年际变化, 海气耦合数值模拟
英文关键词:Indian Ocean, Sea surface temperature, BSISO, Interannual variation, Simulation, Ocean atmosphere couple model
基金项目:Indian Ocean, Sea surface temperature, BSISO, Interannual variation, Simulation, Ocean atmosphere couple model
作者单位
林爱兰 中国气象局广州热带海洋气象研究所, 热带季风重点开放实验室, 广州, 510080 
Tim Li IPRC and Department of Meteorology, University of Hawaii, Honolulu, Hawaii
中国气象局广州热带海洋气象研究所, 热带季风重点开放实验室, 广州, 510080 
李春晖 中国气象局广州热带海洋气象研究所, 热带季风重点开放实验室, 广州, 510080 
谷德军 中国气象局广州热带海洋气象研究所, 热带季风重点开放实验室, 广州, 510080 
郑彬 中国气象局广州热带海洋气象研究所, 热带季风重点开放实验室, 广州, 510080 
Jing Jia Luo Frontier Research Center for Global Change, JAMSTEC, Yokohama, Japan 
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中文摘要:
      利用观测分析资料和SINTEX-F 海气耦合长时间(70年)数值模拟结果,分析了印度洋海温年际异常与热带夏季季节内振荡(BSISO)各种传播模态之间关系及其物理过程。结果表明,印度洋海温年际异常与热带BSISO关系密切,当印度洋为正(负)偶极子情况,中东印度洋北传BSISO减弱(加强);当印度洋为正(负)海盆异常(BWA)情况,印度洋—西太平洋赤道地区(40°E—180°)东传BSISO加强(减弱)。印度洋海温年际变化通过大气环流背景场和BSISO结构影响热带BSISO不同传播模态强度的年际变化。在负(正)偶极子年夏季,由于对流层大气垂直东风切变加强(减弱),对流扰动北侧的正压涡度、边界层水汽辐合加强更明显(不明显),导致形成BSISO较强(弱)的经向不对称结构,因此北传BSISO偏强(减弱)。印度洋BWA模态通过影响赤道西风背景以及海气界面热力交换,导致赤道东传BSISO强度产生变化。在正BWA年夏季,赤道地区西风较明显,当季节内振荡叠加在这种西风背景下,扰动中心的东侧(西侧)风速减弱(加强)更明显,海面蒸发及蒸发潜热减弱(加强)更明显,导致扰动中心的东侧(西侧)海温升高(降低)幅度更大,从而使边界层产生辐合(辐散)更强、水汽更多(少),因此赤道东传BSISO偏强;而在负BWA年,赤道地区西风背景减弱,以上物理过程受削弱使赤道东传BSISO偏弱。
英文摘要:
      Relationships between the interannual anomaly of sea surface temperature (SST) in the tropical Indian Ocean and the different propagation modes of tropical boreal summer intraseasonal oscillations (BSISO) as well as their physical processesare analyzed by using the observational data and long-term (70-year) simulation outputs based on the SINTEX-F ocean atmosphere coupled general circulation model. The results show that interannual SST anomaly over the Indian Ocean may significantly influence both the northward and eastward propagation of BSISO. The northward propagating BSISO over the central and eastern Indian Ocean weakens (strengthens) during the positive (negative) phase of the Indian Ocean dipole. The eastward propagating BSISO over the equatorial Indian Ocean and western Pacific (40°E-180°) strenthens (weakens) during the positive (negative) basin wide anomaly (BWA) condition. The interannual variations of SST in the tropical Indian Ocean affect the variation of the intensity of the different ropagating BSISO modes by modulating the atmospheric background circulation and structure of BSISO. During negative (positive) dipole summers, the increasing (decreasing) of easterly vertical shear in atmospheric troposphere reinforces (reduces) the barotropic vorticity and moisture convergence in the boundary layer at the northern side of the convection distrubance, resulting in a strong (week) meridional asymmetry of BSISO and thus in a stronger (weeker) northward propagating BSISO. The different BWA modes in the Indian Ocean impact the background of equatorial westerlies and thermodynamic exchanges across the air sea interface, causing changes in the intensity of equatorial eastward propagating BSISO. During the positive BWA summer, equatorial westerlies are stronger than the climatological mean. Under this stronger westerlies background, the weakening (strengthening) of wind speed east (west) of the disturbance center is distinct, and so is the evaporation, resulting in larger amplitude of SST increasing (decreasing) to the east (west). The larger amplitude of SST increasing (decreasing) leads to the stronger convergence (divergence) and much more (little) water vapor to the east (west). As a result, the equatorial eastward propagating BSISO is stronger during the positive BWA condition. During the negative BWA summer, equatorial westerlies are weaker than the climatological mean since the above physical process is weakened with the equatorial eastward propagating BSISO weaker.
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