报告题目1The Seasonal Alternate Roles of the North Pacific and the South Pacific in the Equatorial Pacific Zonal Winds and ENSO

报告人钟文秀,博士,中山大学大气科学学院特聘副研究员。2018年毕业于中国海洋大学,曾于2015-2017年赴澳大利亚联邦科学与工业研究院海洋与大气研究中心访问。主要从事热带海洋-大气相互作用、ENSO事件多样性和复杂性成因机制、季风-ENSO相互作用等相关气候动力学研究工作,研究成果发表在《Geophysical Research Letters》等地学主流期刊上,并担任《Frontiers in Climate(Predictions and Projections)》评审编辑。

报告摘要:Zonal wind fluctuations in the central-to-western equatorial Pacific (CWEP) profoundly promote ENSO events by involving in a series of multi-scale air-sea interactions. Using ensemble empirical mode decomposition method, we find that ENSO variance can be mostly attributed by the interannual component of CWEP zonal winds by leading two months. Thus, it is of great significant interest to understand the predictability of these ENSO-related winds. Our result shows that the North Pacific Oscillation and the South Pacific Oscillation alternatively fuel the CWEP zonal wind anomalies from the late boreal winter to the fall. These two subtropical boosters provide clues to the interannual changes in both the CWEP zonal winds and equatorial eastern Pacific sea surface temperatures. The seasonal component of equatorial Pacific is weakly correlated with ENSO, however, which is strongly associated with the East Asian winter monsoon and Australian cross-equatorial flow (CEF) during the boreal summer-fall. These monsoon-related westerly wind anomalies fade in March–April–May, potentially undermining the CWEP westerly winds and the predictability of ENSO in the boreal spring. The result also reflects that the tropical-extratropical interactions are seasonally alternate between the North Hemisphere and the South Hemisphere following the climatic annual cycle.

报告题目2Parameter optimization of marine biogeochemical model by using satellite and BGC-Argo observations in the northern South China Sea
报告人舒婵 2018研究生

报告摘要Marine biogeochemical models have been widely used to understand ecosystem dynamics and biogeochemical cycles. The model parameters are often adjusted based on sporadic in-situ measurements or satellite-derived total chlorophyll concentration at surface. The biogeochemical-Argo (BGC-Argo) float that is able to sample the ocean vertically and continuously provides a unique opportunity to constrain the model. We evaluate the value of assimilating BGC-Argo measurements and satellite-derived PFT data in a biogeochemical model in the northern South China Sea (SCS) by using a genetic algorithm. Using satellite data only does not give the best estimate of the vertical distributions of chlorophyll and POC, which are shown to be largely improved by combining with BGC-Argo data. As the dominant variability of phytoplankton in the northern SCS is at the seasonal timescale, we find that utilizing monthly averaged BGC-Argo profiles leads to the optimal fit between model outputs and measurements, which is better than using high-frequency measurements.





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主持人:张荣望 副研究员,鲁远征 助理研究员