中国科学院 | 大气所 | 网站地图 | 加入收藏
首 页  | | | 论文论著 | | 科学传播 | English  
  新闻信息
最新消息
新闻搜索
最新消息 您当前所在的位置: 首页 > 新闻信息 > 最新消息
Dr. Nicholas Klingaman(Univ. Reading)在我室报告
来源:LASG    访问次数:    更新时间:2017-3-23

The Madden-Julian oscillation in the Super-Parameterized CAM: Air-sea interactions and the role of ENSO

Dr. Nicholas Klingaman
University of Reading

2017年3月23日(星期四)10:00
科研楼303会议室

Abstract

The Super-Parameterized Community Atmospheric Model (SPCAM) is a shining light among contemporary models in the dark abyss of simulated tropical variability, particularly for the Madden-Julian oscillation (MJO).  In atmosphere-only mode, SPCAM simulates a robust MJO, which grows stronger when SPCAM is coupled to a dynamical ocean (SPCCSM).  However, SPCCSM shows similar cold tropical SST errors to those that degrade the representation of the MJO in other models, such as the Met Office model.  The representation of air-sea interactions in SPCCSM is rather poor -- the diurnal cycle is absent and the top ocean layer is 10 metres thick, both of which limit the amplitude and propagation of the MJO in other GCMs.  This raises the question of how SPCCSM manages to produce such an excellent MJO.

We employ a framework in which SPCAM is coupled to an ocean mixed-layer model, which allows the ocean mean state to be controlled.  Under the observed ocean mean state, air-sea interactions only slightly improve the MJO in SPCAM; MJO activity remains below the level seen in SPCCSM.  The SPCCSM ocean mean state substantially weakens the MJO, in contradiction to the strong MJO seen in the SPCCSM simulation itself.  By sub-sampling the SPCCSM simulation, it is clear that SPCCSM produces a robust MJO only in El Niño years, when the warm tropical Pacific SST anomalies cancel the cold mean-state bias.  We confirm this in our mixed-layer ocean configuration, concluding that sub-seasonal air-sea interactions are not important to the MJO in SPCAM.

These results suggest that experiments targeting air-sea interactions in the MJO must control for the effect of inter-annual variability on simulated tropical sub-seasonal variability.

 
© 1997-2010 大气科学和地球流体力学数值模拟国家重点实验室 版权所有 京ICP备06004370号
北京9804信箱LASG 邮编:100029 传真:82995172