题目：Influence of Region-dependent Error Growth on Predictability of Tropical Cyclone Track and Intensity in High-resolution HWRF Ensembles

报告摘要：

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.

个人简介：冯杰，复旦大学青年研究员，博士生导师，2015年毕业于中国科学院大学物理研究所。后在美国国家海洋大气局和俄克拉荷马大学从事博士后研究，并获得俄克拉荷马大学的项目研究员职位。2020年12月至今在复旦大学大气与海洋科学系担任研究员。主要研究方向为台风资料同化和数值预报、大气可预报性和集合预报。长期从事高影响天气的多源数据同化和集合预报的理论方法研究和技术发展。在国际知名期刊上发表多篇研究论文。担任中国青年地学论坛专题召集人。组织AOGS分会。组织Remote Sensing杂志专刊。入选2021年上海青年领军人才计划。

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

报告摘要：

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.

个人简介：王旭栋，复旦大学大气与海洋科学系博士后。于2021年获得南京信息工程大学气象学博士学位，2017-2019年美国加州大学圣迭戈分校Scripps海洋研究所联合培养博士生。主要研究方向为海气相互作用、大气季节内振荡和季风动力学等。