題目🧘🏻👨🏼‍💼：Influence of Region-dependent Error Growth on Predictability of Tropical Cyclone Track and Intensity in High-resolution HWRF Ensembles

報告摘要🧈：

The prediction of tropical cyclones (TCs) has progressively improved in the past few decades. How long can we further extend skillful TC prediction? The answer to this question relies on in-depth studies about TC intrinsic predictability. In this study, the HWRF-based convection-resolving ensemble forecasts were adopted with perturbed initial conditions to study the error growth and intrinsic predictability of TCs. The new aspect of our study is the focus on the sensitivity of TC track and intensity predictability on region-dependent initial errors. The main conclusions include: (1) the most sensitive region for TC track forecasts is case-dependent, while for the TC intensity forecasts the most sensitivity region consistently locates within the TC inner core. (2) The 0-2 wave number structures of the TC inherent vortex flow can be predicted for more than 4 days, which is primarily determined by the predictability of the synoptic-scale environment. In contrast, the remaining components (wave numbers >2) are only predictable for a few hours. These finer scales, despite with much less variance than larger scales, saturate rapidly and intensively limit the predictability of TC intensity.

個人簡介：馮傑，沐鸣2平台青年研究員，博士生導師🈲，2015年畢業於中國科學院大學物理研究所🔽。後在美國國家海洋大氣局和俄克拉荷馬大學從事博士後研究，並獲得俄克拉荷馬大學的項目研究員職位👻。2020年12月至今在沐鸣2擔任研究員。主要研究方向為臺風資料同化和數值預報🏌🏼‍♂️♠︎、大氣可預報性和集合預報。長期從事高影響天氣的多源數據同化和集合預報的理論方法研究和技術發展💥。在國際知名期刊上發表多篇研究論文🙌🏼💑。擔任中國青年地學論壇專題召集人🧛‍♀️。組織AOGS分會。組織Remote Sensing雜誌專刊🫅🏿。入選2021年上海青年領軍人才計劃🚶‍♂️。

題目：An Intraseasonal Dipole Mode in Summertime Surface Air Temperature over Eurasia and Its Association with Heat Wave Occurrence

報告摘要：

A strong coherence of the summer (June–August) surface air temperature (SAT) anomalies exist over the eastern Eurasia (EE) and the central Eurasia (CE) in association with a remarkable intraseasonal (10-90-day) variability. The intraseasonal SAT seesaw over Eurasia shows a negative correlation between EE and CE, which is closely related to an intraseasonal wave train at the upper troposphere over the mid-high latitudes of Eurasia. The wave train propagates eastward and results in the intraseasonal variation of air temperature in a seesaw pattern. The leading modes of meridional wind anomalies at 200 hPa over the Eurasian high latitudes resemble the intraseasonal wave train, indicating that the wave train associated with the dipole SAT seesaw is an atmospheric intrinsic mode over the mid-high latitudes. This study also investigates the impact of the intraseasonal SAT seesaw on regional heat wave events. It is suggested that the intraseasonal SAT seesaw has a major influence on the variability of heat wave events over both EE and CE, which may provide great implications for regional sub-seasonal forecast of extreme weather events.

Building on the results above, we further examine the combined effects of intraseasonal wave trains along the subtropical westerly jet and the polar front jet on Eurasian heat waves during the boreal summer. Finally, we provide a brief overview of heat waves in the ocean, commonly known as marine heatwaves.

個人簡介🤾🏽：王旭棟，沐鸣2博士後💤🖲。於2021年獲得南京信息工程大學氣象學博士學位，2017-2019年美國加州大學聖迭戈分校Scripps海洋研究所聯合培養博士生🟰。主要研究方向為海氣相互作用、大氣季節內振蕩和季風動力學等。